Direct trans-activation of the human cyclin D2 gene by the oncogene product Tax of human T-cell leukemia virus type I.

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Huang, Y; Ohtani, K; Iwanaga, R; Matsumura, Y; Nakamura, M

2001-03-01

Cyclins are one of the pivotal determinants regulating cell cycle progression. We previously reported that the trans-activator Tax of human T-cell leukemia virus type I (HTLV-I) induces endogenous cyclin D2 expression along with cell cycle progression in a resting human T-cell line, Kit 225, suggesting a role of cyclin D2 in Tax-mediated cell cycle progression. The cyclin D2 gene has a typical E2F binding element, raising the possibility that induction of cyclin D2 expression is a consequence of cell cycle progression. In this study, we examined the role and molecular mechanism of induction of the endogenous human cyclin D2 gene by Tax. Introduction of p19(INK4d), a cyclin dependent kinase (CDK) inhibitor of the INK4 family specific for D-type CDK, inhibited Tax-mediated activation of E2F, indicating requirement of D-type CDK in Tax-mediated activation of E2F. Previously indicated E2F binding element and two NF-kappaB-like binding elements in the 1.6 kbp cyclin D2 promoter fragment had little, if any, effect on responsiveness to Tax. We found that trans-activation of the cyclin D2 promoter by Tax was mainly mediated by a newly identified NF-kappaB-like element with auxiliary contribution of a CRE-like element residing in sequences downstream of -444 which were by themselves sufficient for trans-activation by Tax. These results indicate that Tax directly trans-activates the cyclin D2 gene, resulting in growth promotion and perhaps leukemogenesis through activation of D-type CDK.

Cyclin A regulates a cell-cycle-dependent expression of CKAP2 through phosphorylation of Sp1

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Kang, Du-Seock; Hong, Kyeong-Man; Park, Joobae; Bae, Chang-Dae

2012-01-01

Highlights: ► We identified a GC box and a CHR element in human CKAP2 minimal promoter. ► The CHR element repressed the CKAP2 minimal promoter activity at the G1/S phase. ► The GC box was essential for the basic promoter activity of human CKAP2. ► The GC box was also essential for the cyclic expression of human CKAP2. ► The phosphorylation of Sp1, mediated by Cyclin A, underlies the cyclic expression. -- Abstract: CKAP2 plays crucial roles in proper chromosome segregation and maintaining genomic stability. CKAP2 protein showed cell-cycle-dependent expression, which reached a maximum level at the G2/M phase and disappeared at the onset of G1 phase. To elucidate the mechanisms underlying cell cycle-dependent expression of CKAP2, we cloned and analyzed the human CKAP2 promoter. The upstream 115-bp region from the transcription start site was sufficient for minimal CKAP2 promoter activity. We identified 2 regulatory sequences; a CHR (−110 to −104 bp) and a GC box (−41 to −32 bp). We confirmed Sp1 bound to the GC box using a supershift assay and a ChIP assay. Mutation in the GC box resulted in a near complete loss of CKAP2 promoter activity while mutation in the CHR decreased the promoter activity by 50%. The CHR mutation showed enhanced activity at the G1/S phase, but still retained cyclic activity. The Chromatin IP revealed that the amount of Sp1 bound to the GC box gradually increased and reached a maximum level at the G2/M phase. The amount of Sp1 bound to the GC box was greatly reduced when Cyclin A was depleted, which was restored by adding Cyclin A/Cdk2 complex back into the nuclear extracts. Together, we concluded that the GC box was responsible for the cyclic activity of human CKAP2 promoter through the phosphorylation of Sp1, possibly by Cyclin A/Cdk complex.

Induced ICER Iγ down-regulates cyclin A expression and cell proliferation in insulin-producing β cells

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Inada, Akari; Weir, Gordon C.; Bonner-Weir, Susan

2005-01-01

We have previously found that cyclin A expression is markedly reduced in pancreatic β-cells by cell-specific overexpression of repressor inducible cyclic AMP early repressor (ICER Iγ) in transgenic mice. Here we further examined regulatory effects of ICER Iγ on cyclin A gene expression using Min6 cells, an insulin-producing cell line. The cyclin A promoter luciferase assay showed that ICER Iγ directly repressed cyclin A gene transcription. In addition, upon ICER Iγ overexpression, cyclin A mRNA levels markedly decreased, thereby confirming an inhibitory effect of ICER Iγ on cyclin A expression. Suppression of cyclin A results in inhibition of BrdU incorporation. Under normal culture conditions endogenous cyclin A is abundant in these cells, whereas ICER is hardly detectable. However, serum starvation of Min6 cells induces ICER Iγ expression with a concomitant very low expression level of cyclin A. Cyclin A protein is not expressed unless the cells are in active DNA replication. These results indicate a potentially important anti-proliferative effect of ICER Iγ in pancreatic β cells. Since ICER Iγ is greatly increased in diabetes as well as in FFA- or high glucose-treated islets, this effect may in part exacerbate diabetes by limiting β-cell proliferation

Cyclin D1 Expression and Its Correlation with Histopathological Differentiation in Oral Squamous Cell Carcinoma

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Swati Saawarn

2012-01-01

Full Text Available Background. Cyclin D1 regulates the G1 to S transition of cell cycle. Its deregulation or overexpression may lead to disturbance in the normal cell cycle control and tumour formation. Overexpression of cyclin D1 has been reported in various tumors of diverse histogenesis. This case control retrospective study was carried out to study the immunohistochemical reactivity and expression of cyclin D1 and its association with site, clinical staging, and histopathological differentiation of oral squamous cell carcinoma (OSCC. Methods. Forty formalin-fixed paraffin-embedded tissue blocks of biopsy specimens of oral squamous cell carcinoma were immunohistochemically evaluated for expression of cyclin D1. Results. Cyclin D1 expression was seen in 45% cases of OSCC. It did not correlate with site and clinical staging. Highest expression was seen in well-differentiated, followed by moderately differentiated, and poorly differentiated squamous cell carcinomas, with a statistically significant correlation. Conclusion. Cyclin D1 expression significantly increases with increase in differentiation.

Limited prognostic value of tissue protein expression levels of cyclin E in Danish ovarian cancer patients

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Heeran, Mel C; Høgdall, Claus K; Kjaer, Susanne K

2012-01-01

The primary objective of this study was to assess the expression of cyclin E in tumour tissues from 661 patients with epithelial ovarian tumours. The second was to evaluate whether cyclin E tissue expression levels correlate with clinico-pathological parameters and prognosis of the disease. Using...... tissue arrays (TA), we analysed the cyclin E expression levels in tissues from 168 women with borderline ovarian tumours (BOT) (147 stage I, 4 stage II, 17 stage III) and 493 Ovarian cancer (OC) patients (127 stage I, 45 stage II, 276 stage III, 45 stage IV). Using a 10% cut-off level for cyclin E......-off value showed that cyclin E had no independent prognostic value. In conclusion, we found cyclin E expression in tumour tissue to be of limited prognostic value to Danish OC patients....

Cyclin K and cyclin D1b are oncogenic in myeloma cells

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Renoir Jack-Michel

2010-05-01

Full Text Available Abstract Background Aberrant expression of cyclin D1 is a common feature in multiple myeloma (MM and always associated with mantle cell lymphoma (MCL. CCND1 gene is alternatively spliced to produce two cyclin D1 mRNA isoforms which are translated in two proteins: cyclin D1a and cyclin D1b. Both isoforms are present in MM cell lines and primary cells but their relative role in the tumorigenic process is still elusive. Results To test the tumorigenic potential of cyclin D1b in vivo, we generated cell clones derived from the non-CCND1 expressing MM LP-1 cell line, synthesizing either cyclin D1b or cyclin K, a structural homolog and viral oncogenic form of cyclin D1a. Immunocompromised mice injected s.c. with LP-1K or LP-1D1b cells develop tumors at the site of injection. Genome-wide analysis of LP-1-derived cells indicated that several cellular processes were altered by cyclin D1b and/or cyclin K expression such as cell metabolism, signal transduction, regulation of transcription and translation. Importantly, cyclin K and cyclin D1b have no major action on cell cycle or apoptosis regulatory genes. Moreover, they impact differently cell functions. Cyclin K-expressing cells have lost their migration properties and display enhanced clonogenic capacities. Cyclin D1b promotes tumorigenesis through the stimulation of angiogenesis. Conclusions Our study indicates that cyclin D1b participates into MM pathogenesis via previously unrevealed actions.

Prognostic significance of cyclin D1 protein expression and gene amplification in invasive breast carcinoma.

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Angela B Ortiz

Full Text Available The oncogenic capacity of cyclin D1 has long been established in breast cancer. CCND1 amplification has been identified in a subset of patients with poor prognosis, but there are conflicting data regarding the predictive value of cyclin D1 protein overexpression. This study was designed to analyze the expression of cyclin D1 and its correlation with CCND1 amplification and their prognostic implications in invasive breast cancer. By using the tissue microarray technique, we performed an immunohistochemical study of ER, PR, HER2, p53, cyclin D1, Ki67 and p16 in 179 invasive breast carcinoma cases. The FISH method was performed to detect HER2/Neu and CCND1 amplification. High cyclin D1 expression was identified in 94/179 (52% of invasive breast cancers. Cyclin D1 overexpression and CCND1 amplification were significantly associated (p = 0.010. Overexpression of cyclin D1 correlated with ER expression, PR expression and Luminal subtypes (p<0.001, with a favorable impact on overall survival in the whole series. However, in the Luminal A group, high expression of cyclin D1 correlated with shorter disease-free survival, suggesting that the prognostic role of cyclin D1 depends on the molecular subtype. CCND1 gene amplification was detected in 17 cases (9% and correlated significantly with high tumor grade (p = 0.038, high Ki-67 protein expression (p = 0.002, and the Luminal B subtype (p = 0.002. Patients with tumors with high amplification of CCND1 had an increased risk of recurrence (HR = 2.5; 95% CI, 1.2-4.9, p = 0.01. These findings suggest that CCND1 amplification could be useful for predicting recurrence in invasive breast cancer.

Cyclin H expression is increased in GIST with very-high risk of malignancy

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Dorn, Julian; Spatz, Hanno; Schmieder, Michael; Barth, Thomas FE; Blatz, Annette; Henne-Bruns, Doris; Knippschild, Uwe; Kramer, Klaus

2010-01-01

Risk estimation of gastrointestinal stromal tumours (GIST) is based on tumour size and mitotic rate according to the National Institutes of Health consensus classification. The indication for adjuvant treatment of patients with high risk GIST after R 0 resection with small molecule inhibitors is still a controversial issue, since these patients represent a highly heterogeneous population. Therefore, additional prognostic indicators are needed. Here, we evaluated the prognostic value of cyclin H expression in GIST. In order to identify prognostic factors of GIST we evaluated a single centre cohort of ninety-five GIST patients. First, GISTs were classified with regard to tumour size, mitotic rate and localisation according to the NIH consensus and to three additional suggested risk classifications. Second, Cyclin H expression was analysed. Of ninety-five patients with GIST (53 female/42 male; median age: 66.78a; range 17-94a) risk classification revealed: 42% high risk, 20% intermediate risk, 23% low risk and 15% very low risk GIST. In patients with high risk GIST, the expression of cyclin H was highly predictive for reduced disease-specific survival (p = 0.038). A combination of cyclin H expression level and high risk classification yielded the strongest prognostic indicator for disease-specific and disease-free survival (p ≤ 0.001). Moreover, in patients with tumour recurrence and/or metastases, cyclin H positivity was significantly associated with reduced disease-specific survival (p = 0.016) regardless of risk-classification. Our data suggest that, in addition to high risk classification, cyclin H expression might be an indicator for 'very-high risk' GIST

Expression of cyclin A in A549 cell line after treatment with arsenic trioxide

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Agnieszka Żuryń

2015-12-01

Full Text Available Background: Arsenic trioxide (ATO is an effective drug used in acute promyelocytic leukemia (AML. Many reports suggest that ATO can also be applied as an anticancer agent for solid tumors in the future. The influence of arsenic trioxide on the expression of different cell cycle regulators is poorly recognized. The purpose of the current study is to investigate how arsenic trioxide affects cyclin A expression and localization in the A549 cell line.Materials and methods: Morphological and ultrastructural changes in A549 cells were observed using light and transmission electron microscopes. Cyclin A localization was determined by immunofluorescence. Image-based cytometry was applied to evaluate the effect of arsenic trioxide on apoptosis and the cell cycle. Expression of cyclin A mRNA was quantified by real-time PCR.Results: After treatment with arsenic trioxide, increased numbers of cells with cytoplasmic localization of cyclin A were observed. The doses of 10 and 15 μM ATO slightly reduced expression of cyclin A mRNA. The apoptotic phenotype of cells was poorly represented, and the Tali imagebased cytometry analysis showed low percentages of apoptotic cells. The A549 population displayed an enriched fraction of cells in G0/G1 phase in the presence of 5μM ATO, whereas starting from the higher concentrations of the drug, i.e. 10 and 15 μM ATO, the G2/M fraction was on the increase.Discussion: Low expression of cyclin A in the A549 cell line may constitute a potential factor determining arsenic trioxide resistance. It could be hypothesized that the observed alterations in cyclin A expression/distribution may correlate well with changes in cell cycle regulation in our model, which in turn determines the outcome of the treatment.

The validity of immunocytochemical expression of cyclin D1 in fine needle aspiration cytology of breast carcinoma

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Ezzat, N.; Hafez, N.

2012-01-01

Purpose: The aim of this work is to study the validity of cyclin D1 expression, a cell Fenac; cycle regulatory protein, on (fine needle aspiration cytology) FNAC samples in patients with breast Breast carcinoma; carcinoma using immunostaining technique. Cyclin D1 Patient and methods: This is a study done on 70 patients with primary breast carcinoma, presented to Cytology Unit, Pathology Department, National Cancer Institute, Cairo University. They underwent preoperative FNAC and diagnosed as breast carcinoma. The cytologic and tissue section slides were subjected to cyclin D1 immunocytochemical staining. Only the nuclear immunoreactivity for cyclin D1 was considered specific. The rate of concordance, and discordance, and kappa value were calculated. Relation between cytologic expression of cyclin D1 and different clinico pathologic parameters was evaluated. Results: Cyclin D1 immunocytochemical expression was observed in 53/70 cases (75.7%) in cytologic smears. In histologic sections of the corresponding cases, cyclin D1 was detected in 48/70 cases (68.6%). The concordance rate of cyclin D1 expression in the FNA and histologic sections was 87.1% while the discordance rate was 12.9%. Kappa showed a value of 0.65. A statistically significant relation was found between cyclin D1 immunocytochemical expression and hormonal status as well as nuclear grade. Conclusion: Cyclin D1 immunocytochemical expression can be performed successfully on cytologic samples with a high concordance rate and agreement with histologic results. This can help in determining tumor biology, and plan for patients treatment. The marker showed a significant relation with hormone receptor status and nuclear grade

miR-340 inhibits glioblastoma cell proliferation by suppressing CDK6, cyclin-D1 and cyclin-D2

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Li, Xuesong; Gong, Xuhai; Chen, Jing; Zhang, Jinghui; Sun, Jiahang; Guo, Mian

2015-01-01

Glioblastoma development is often associated with alteration in the activity and expression of cell cycle regulators, such as cyclin-dependent kinases (CKDs) and cyclins, resulting in aberrant cell proliferation. Recent studies have highlighted the pivotal roles of miRNAs in controlling the development and growth of glioblastoma. Here, we provide evidence for a function of miR-340 in the inhibition of glioblastoma cell proliferation. We found that miR-340 is downregulated in human glioblastoma tissue samples and several established glioblastoma cell lines. Proliferation and neurosphere formation assays revealed that miR-340 plays an oncosuppressive role in glioblastoma, and that its ectopic expression causes significant defect in glioblastoma cell growth. Further, using bioinformatics, luciferase assay and western blot, we found that miR-340 specifically targets the 3′UTRs of CDK6, cyclin-D1 and cyclin-D2, leading to the arrest of glioblastoma cells in the G0/G1 cell cycle phase. Confirming these results, we found that re-introducing CDK6, cyclin-D1 or cyclin-D2 expression partially, but significantly, rescues cells from the suppression of cell proliferation and cell cycle arrest mediated by miR-340. Collectively, our results demonstrate that miR-340 plays a tumor-suppressive role in glioblastoma and may be useful as a diagnostic biomarker and/or a therapeutic avenue for glioblastoma. - Highlights: • miR-340 is downregulated in glioblastoma samples and cell lines. • miR-340 inhibits glioblastoma cell proliferation. • miR-340 directly targets CDK6, cyclin-D1, and cyclin-D2. • miR-340 regulates glioblastoma cell proliferation via CDK6, cyclin-D1 and cyclin-D2

miR-340 inhibits glioblastoma cell proliferation by suppressing CDK6, cyclin-D1 and cyclin-D2

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Li, Xuesong; Gong, Xuhai [Department of Neurology, Daqing Oilfield General Hospital, Daqing, Heilongjiang 163001 (China); Chen, Jing [Department of Neurology, Daqing Longnan Hospital, Daqing, Heilongjiang, 163001 China (China); Zhang, Jinghui [Department of Cardiology, The Fourth Hospital of Harbin City, Harbin, Heilongjiang 150026 (China); Sun, Jiahang [Department of Neurosurgery, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086 (China); Guo, Mian, E-mail: guomian_hyd@163.com [Department of Neurosurgery, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086 (China)

2015-05-08

Glioblastoma development is often associated with alteration in the activity and expression of cell cycle regulators, such as cyclin-dependent kinases (CKDs) and cyclins, resulting in aberrant cell proliferation. Recent studies have highlighted the pivotal roles of miRNAs in controlling the development and growth of glioblastoma. Here, we provide evidence for a function of miR-340 in the inhibition of glioblastoma cell proliferation. We found that miR-340 is downregulated in human glioblastoma tissue samples and several established glioblastoma cell lines. Proliferation and neurosphere formation assays revealed that miR-340 plays an oncosuppressive role in glioblastoma, and that its ectopic expression causes significant defect in glioblastoma cell growth. Further, using bioinformatics, luciferase assay and western blot, we found that miR-340 specifically targets the 3′UTRs of CDK6, cyclin-D1 and cyclin-D2, leading to the arrest of glioblastoma cells in the G0/G1 cell cycle phase. Confirming these results, we found that re-introducing CDK6, cyclin-D1 or cyclin-D2 expression partially, but significantly, rescues cells from the suppression of cell proliferation and cell cycle arrest mediated by miR-340. Collectively, our results demonstrate that miR-340 plays a tumor-suppressive role in glioblastoma and may be useful as a diagnostic biomarker and/or a therapeutic avenue for glioblastoma. - Highlights: • miR-340 is downregulated in glioblastoma samples and cell lines. • miR-340 inhibits glioblastoma cell proliferation. • miR-340 directly targets CDK6, cyclin-D1, and cyclin-D2. • miR-340 regulates glioblastoma cell proliferation via CDK6, cyclin-D1 and cyclin-D2.

The Role of Cyclins and Cyclins Inhibitors in the Multistep Process of HPV-Associated Cervical Carcinoma

International Nuclear Information System (INIS)

Bahnassy, A.A.; Mokhtar, N.M.; Zekri, A.; Alam El-Din, H.M.; Aboubaker, A.A.; Kamel, K.; El-Sabah, M.T.

2006-01-01

Background: Human papillomavirus (HPV) types 16 and 18 are associated with cervical carcinogenesis. This is possibly achieved through an interaction between HPV oncogenic proteins and some cell cycle regulatory genes. However, the exact pathogenetic mechanisms are not well defined yet. Methods: We investigated 110 subjects (43 invasive squamous cell carcinoma [ISCC], 38 CIN Ill, II CIN II, 18 CIN I) confirmed to be positive for HPV 16 and/or 18 as well as 20 normal cervical tissue (NCT) samples for abnormal expression of cyclin DJ, cyclin E, CDK4, cyclin inhibitors (p2Jwa/; p27, pI6/NK4A) and Ki-67 using immunohistochemistry and differential PCR techniques. Results: There was a significant increase in the expression of Ki-67, cyclin E, CDK4, pJ6/NK4A (p=0003, 0.001,0.001) and a significant decrease in p27K1P/ from NCT to ISCC (p=0.003). There was a significant correlation between altered expression of p27K1P I and p 161NK4A (p KIpl (ρ=0.011) in all studied groups In ISCC, there was significant relationship between standard clinico-pathological prognostic factors and high Ki-67 index, increased cyclin D J and cyclin E, reduced p2 7Kip / and p21 waf Conclusion: I) Aberrations involving p27K/P 1, cyclin E, CDK4 and pJ6/NK4A are considered early events in HPV 16 and IS-associated cervical carcinogenesis (CINI and lI), whereas cyclin DI aberrations are late events (CINIII and ISCC). 2) immunohistochemical tests for pJ61NK4A and cyclin E could help in early diagnosis of cervical carcinoma. 3) Only FIGO stage, cyclin DI, p27K1P1 and Ki-67 are independent prognostic factors that might help in predicting outcome of cervical cancer palients

Gene structure, expression, and DNA methylation characteristics of sea cucumber cyclin B gene during aestivation.

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Zhu, Aijun; Chen, Muyan; Zhang, Xiumei; Storey, Kenneth B

2016-12-05

The sea cucumber, Apostichopus japonicus, is a good model for studying environmentally-induced aestivation by a marine invertebrate. One of the central requirements of aestivation is the repression of energy-expensive cellular processes such as cell cycle progression. The present study identified the gene structure of the cell cycle regulator, cyclin B, and detected the expression levels of this gene over three stages of the annual aestivation-arousal cycle. Furthermore, the DNA methylation characteristics of cyclin B were analyzed in non-aestivation and deep-aestivation stages of sea cucumbers. We found that the cyclin B promoter contains a CpG island, three CCAAT-boxes and three cell cycle gene homology regions (CHRs). Application of qRT-PCR analysis showed significant downregulation of cyclin B transcript levels during deep-aestivation in comparison with non-aestivation in both intestine and longitudinal muscle, and these returned to basal levels after arousal from aestivation. Methylation analysis of the cyclin B core promoter revealed that its methylation level showed significant differences between non-aestivation and deep-aestivation stages (p<0.05) and interestingly, a positive correlation between Cyclin B transcripts expression and methylation levels of the core promoter was also observed. Our findings suggest that cell cycle progression may be reversibly arrested during aestivation as indicated by the changes in cyclin B expression levels and we propose that DNA methylation is one of the regulatory mechanisms involved in cyclin B transcriptional variation. Copyright © 2016 Elsevier B.V. All rights reserved.

The 3' untranslated region of the cyclin B mRNA is not sufficient to enhance the synthesis of cyclin B during a mitotic block in human cells.

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Dominik Schnerch

Full Text Available Antimitotic agents are frequently used to treat solid tumors and hematologic malignancies. However, one major limitation of antimitotic approaches is mitotic slippage, which is driven by slow degradation of cyclin B during a mitotic block. The extent to which cyclin B levels decline is proposed to be governed by an equilibrium between cyclin B synthesis and degradation. It was recently shown that the 3' untranslated region (UTR of the murine cyclin B mRNA contributes to the synthesis of cyclin B during mitosis in murine cells. Using a novel live-cell imaging-based technique allowing us to study synthesis and degradation of cyclin B simultaneously at the single cell level, we tested here the role of the human cyclin B 3'UTR in regulating cyclin B synthesis during mitosis in human cells. We observed that the cyclin B 3'UTR was not sufficient to enhance cyclin B synthesis in human U2Os, HeLa or hTERT RPE-1 cells. A better understanding of how the equilibrium of cyclin B is regulated in mitosis may contribute to the development of improved therapeutic approaches to prevent mitotic slippage in cancer cells treated with antimitotic agents.

Cannabinoids Regulate Bcl-2 and Cyclin D2 Expression in Pancreatic β Cells.

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Jihye Kim

Full Text Available Recent reports have shown that cannabinoid 1 receptors (CB1Rs are expressed in pancreatic β cells, where they induce cell death and cell cycle arrest by directly inhibiting insulin receptor activation. Here, we report that CB1Rs regulate the expression of the anti-apoptotic protein Bcl-2 and cell cycle regulator cyclin D2 in pancreatic β cells. Treatment of MIN6 and βTC6 cells with a synthetic CB1R agonist, WIN55,212-2, led to a decrease in the expression of Bcl-2 and cyclin D2, in turn inducing cell cycle arrest in G0/G1 phase and caspase-3-dependent apoptosis. Additionally, genetic deletion and pharmacological blockade of CB1Rs after injury in mice led to increased levels of Bcl-2 and cyclin D2 in pancreatic β cells. These findings provide evidence for the involvement of Bcl-2 and cyclin D2 mediated by CB1Rs in the regulation of β-cell survival and growth, and will serve as a basis for developing new therapeutic interventions to enhance β-cell function and growth in diabetes.

Anticancer activity of calyx of Diospyros kaki Thunb. through downregulation of cyclin D1 via inducing proteasomal degradation and transcriptional inhibition in human colorectal cancer cells.

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Park, Su Bin; Park, Gwang Hun; Song, Hun Min; Son, Ho-Jun; Um, Yurry; Kim, Hyun-Seok; Jeong, Jin Boo

2017-09-05

Although it has been reported to contain high polyphenols, the pharmacological studies of the calyx of Diospyros kaki Thunb (DKC) have not been elucidated in detail. In this study, we elucidated anti-cancer activity and potential molecular mechanism of DKC against human colorectal cancer cells. Anti-cell proliferative effect of 70% ethanol extracts from the calyx of Diospyros kaki (DKC-E70) was evaluated by MTT assay. The effect of DKC-E70 on the expression of cyclin D1 in the protein and mRNA level was evaluated by Western blot and RT-PCR, respectively. DKC-E70 suppressed the proliferation of human colorectal cancer cell lines such as HCT116, SW480, LoVo and HT-29. Although DKC-E70 decreased cyclin D1 expression in protein and mRNA level, decreased level of cyclin D1 protein by DKC-E70 occurred at the earlier time than that of cyclin D1 mRNA, which indicates that DKC-E70-mediated downregulation of cyclin D1 protein may be a consequence of the induction of degradation and transcriptional inhibition of cyclin D1. In cyclin D1 degradation, we found that cyclin D1 downregulation by DKC-E70 was attenuated in presence of MG132. In addition, DKC-E70 phosphorylated threonine-286 (T286) of cyclin D1 and T286A abolished cyclin D1 downregulation by DKC-E70. We also observed that DKC-E70-mediated T286 phosphorylation and subsequent cyclin D1 degradation was blocked in presence of the inhibitors of ERK1/2, p38 or GSK3β. In cyclin D1 transcriptional inhibition, DKC-E70 inhibited the expression of β-catenin and TCF4, and β-catenin/TCF-dependent luciferase activity. Our results suggest that DKC-E70 may downregulate cyclin D1 as one of the potential anti-cancer targets through cyclin D1 degradation by T286 phosphorylation dependent on ERK1/2, p38 or GSK3β, and cyclin D1 transcriptional inhibition through Wnt signaling. From these findings, DKC-E70 has potential to be a candidate for the development of chemoprevention or therapeutic agents for human colorectal cancer.

Prevalence and clinical implications of cyclin D1 expression in diffuse large B-cell lymphoma (DLBCL) treated with immunochemotherapy

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Ok, Chi Young; Xu-Monette, Zijun Y; Tzankov, Alexandar

2014-01-01

oncogene E3 ubiquitin protein ligase (MDM2), MDM4, and tumor protein 53 (TP53) were rare or absent. Gene expression profiling did not reveal any striking differences with respect to cyclin D1 in DLBCL. CONCLUSIONS: Compared with patients who had cyclin D1-negative DLBCL, men were more commonly affected......1-positive according to immunohistochemistry were also assessed for rearrangements of the cyclin D1 gene (CCND1) using fluorescence in situ hybridization. Gene expression profiling was performed to compare patients who had DLBCL with and without cyclin D1 expression. RESULTS: In total, 30 patients...... (2.1%) who had DLBCL that expressed cyclin D1 and lacked CCND1 gene rearrangements were identified. Patients with cyclin D1-positive DLBCL had a median age of 57 years (range, 16.0-82.6 years). There were 23 males and 7 females. Twelve patients (40%) had bulky disease. None of them expressed CD5. Two...

HuR cytoplasmic expression is associated with increased cyclin A expression and poor outcome with upper urinary tract urothelial carcinoma

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Liang, Peir-In; Shiue, Yow-Ling; Huang, Hsuan-Ying; Hsu, Han-Ping; Chen, Li-Tzon; Lin, Ching-Yih; Tai, Chein; Lin, Chun-Mao; Li, Chien-Feng; Li, Wei-Ming; Wang, Yu-Hui; Wu, Ting-Feng; Wu, Wen-Ren; Liao, Alex C; Shen, Kun-Hung; Wei, Yu-Ching; Hsing, Chung-Hsi

2012-01-01

HuR is an RNA-binding protein that post-transcriptionally modulates the expressions of various target genes implicated in carcinogenesis, such as CCNA2 encoding cyclin A. No prior study attempted to evaluate the significance of HuR expression in a large cohort with upper urinary tract urothelial carcinomas (UTUCs). In total, 340 cases of primary localized UTUC without previous or concordant bladder carcinoma were selected. All of these patients received ureterectomy or radical nephroureterectomy with curative intents. Pathological slides were reviewed, and clinical findings were collected. Immunostaining for HuR and cyclin A was performed and evaluated by using H-score. The results of cytoplasmic HuR and nuclear cyclin A expressions were correlated with disease-specific survival (DSS), metastasis-free survival (MeFS), urinary bladder recurrence-free survival (UBRFS), and various clinicopathological factors. HuR cytoplasmic expression was significantly related to the pT status, lymph node metastasis, a higher histological grade, the pattern of invasion, vascular and perineurial invasion, and cyclin A expression (p = 0.005). Importantly, HuR cytoplasmic expression was strongly associated with a worse DSS (p < 0.0001), MeFS (p < 0.0001), and UBRFS (p = 0.0370) in the univariate analysis, and the first two results remained independently predictive of adverse outcomes (p = 0.038, relative risk [RR] = 1.996 for DSS; p = 0.027, RR = 1.880 for MeFS). Cyclin A nuclear expression was associated with a poor DSS (p = 0.0035) and MeFS (p = 0.0015) in the univariate analysis but was not prognosticatory in the multivariate analyses. High-risk patients (pT3 or pT4 with/without nodal metastasis) with high HuR cytoplasmic expression had better DSS if adjuvant chemotherapy was performed (p = 0.015). HuR cytoplasmic expression was correlated with adverse phenotypes and cyclin A overexpression and also independently predictive of worse DSS and MeFS, suggesting its roles in

Inverse relationship between TCTP/RhoA and p53/ /cyclin A/actin expression in ovarian cancer cells Inverse relationship between TCTP/RhoA and p53/ /cyclin A/actin expression in ovarian cancer cells

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Malgorzata Kloc

2012-10-01

Full Text Available The translationally controlled tumor protein (TCTP plays a role in cell growth, cell cycle and cancer
progression. TCTP controls negatively the stability of the p53 tumor suppressor protein and interacts with the
cellular cytoskeleton. The deregulation of the actin and cytokeratin cytoskeleton is responsible for the increased
migratory activity of tumor cells and is linked with poor patient outcome. Recent studies indicate that cyclin A,
a key regulator of cell cycle, controls actin organization and negatively regulates cell motility via regulation of RhoA
expression. We studied the organization of actin and cytokeratin cytoskeleton and the expression of TCTP, p53,
cyclin A, RhoA and actin in HIO180 non-transformed ovarian epithelial cells, and OVCAR3 and SKOV3 (expressing
low level of inducible p53 ovarian epithelial cancer cells with different metastatic potential. Immunostaining
and ultrastructural analyses illustrated a dramatic difference in the organization of the cytokeratin and actin
filaments in non-transformed versus cancer cell lines. We also determined that there is an inverse relationship between
the level of TCTP/RhoA and actin/p53/cyclin A expression in ovarian cancer cell lines. This previously unidentified
negative relationship between TCTP/RhoA and actin/p53/cyclin A may suggest that this interaction is linked
with the high aggressiveness of ovarian cancers.The translationally controlled tumor protein (TCTP plays a role in cell growth, cell cycle and cancer
progression. TCTP controls negatively the stability of the p53 tumor suppressor protein and interacts with the
cellular cytoskeleton. The deregulation of the actin and cytokeratin cytoskeleton is responsible for the increased
migratory activity of tumor cells and is linked with poor patient outcome. Recent studies indicate that cyclin A,
a key regulator of cell cycle, controls actin organization

The dual role of cyclin C connects stress regulated gene expression to mitochondrial dynamics

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Randy Strich

2014-09-01

Full Text Available Following exposure to cytotoxic agents, cellular damage is first recognized by a variety of sensor mechanisms. Thenceforth, the damage signal is transduced to the nucleus to install the correct gene expression program including the induction of genes whose products either detoxify destructive compounds or repair the damage they cause. Next, the stress signal is disseminated throughout the cell to effect the appropriate changes at organelles including the mitochondria. The mitochondria represent an important signaling platform for the stress response. An initial stress response of the mitochondria is extensive fragmentation. If the damage is prodigious, the mitochondria fragment (fission and lose their outer membrane integrity leading to the release of pro-apoptotic factors necessary for programmed cell death (PCD execution. As this complex biological process contains many moving parts, it must be exquisitely coordinated as the ultimate decision is life or death. The conserved C-type cyclin plays an important role in executing this molecular Rubicon by coupling changes in gene expression to mitochondrial fission and PCD. Cyclin C, along with its cyclin dependent kinase partner Cdk8, associates with the RNA polymerase holoenzyme to regulate transcription. In particular, cyclin C-Cdk8 repress many stress responsive genes. To relieve this repression, cyclin C is destroyed in cells exposed to pro-oxidants and other stressors. However, prior to its destruction, cyclin C, but not Cdk8, is released from its nuclear anchor (Med13, translocates from the nucleus to the cytoplasm where it interacts with the fission machinery and is both necessary and sufficient to induce extensive mitochondria fragmentation. Furthermore, cytoplasmic cyclin C promotes PCD indicating that it mediates both mitochondrial fission and cell death pathways. This review will summarize the role cyclin C plays in regulating stress-responsive transcription. In addition, we will detail

Cardiac insulin-like growth factor-1 and cyclins gene expression in canine models of ischemic or overpacing cardiomyopathy.

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Mahmoudabady, Maryam; Mathieu, Myrielle; Touihri, Karim; Hadad, Ielham; Da Costa, Agnes Mendes; Naeije, Robert; Mc Entee, Kathleen

2009-10-09

Insulin-like growth factor-1 (IGF-1), transforming growth factor beta (TGFbeta) and cyclins are thought to play a role in myocardial hypertrophic response to insults. We investigated these signaling pathways in canine models of ischemic or overpacing-induced cardiomyopathy. Echocardiographic recordings and myocardial sampling for measurements of gene expressions of IGF-1, its receptor (IGF-1R), TGFbeta and of cyclins A, B, D1, D2, D3 and E, were obtained in 8 dogs with a healed myocardial infarction, 8 dogs after 7 weeks of overpacing and in 7 healthy control dogs. Ischemic cardiomyopathy was characterized by moderate left ventricular systolic dysfunction and eccentric hypertrophy, with increased expressions of IGF-1, IGF-1R and cyclins B, D1, D3 and E. Tachycardiomyopathy was characterized by severe left ventricular systolic dysfunction and dilation with no identifiable hypertrophic response. In the latter model, only IGF-1 was overexpressed while IGF-1R, cyclins B, D1, D3 and E stayed unchanged as compared to controls. The expressions of TGFbeta, cyclins A and D2 were comparable in the 3 groups. The expression of IGF-1R was correlated with the thickness of the interventricular septum, in systole and diastole, and to cyclins B, D1, D3 and E expression. These results agree with the notion that IGF-1/IGF-1R and cyclins are involved in the hypertrophic response observed in cardiomyopathies.

Lysine-specific demethylase 2A expression is associated with cell growth and cyclin D1 expression in colorectal adenocarcinoma.

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Cao, Lin-Lin; Du, Changzheng; Liu, Hangqi; Pei, Lin; Qin, Li; Jia, Mei; Wang, Hui

2018-04-01

Lysine-specific demethylase 2A (KDM2A), a specific H3K36me1/2 demethylase, has been reported to be closely associated with several types of cancer. In this study, we aimed to investigate the expression and function of KDM2A in colorectal adenocarcinoma. A total of 215 colorectal adenocarcinoma specimens were collected, and then subjected to immunohistochemistry assay to evaluate the expression levels of KDM2A, cyclin D1 and other proteins in colorectal adenocarcinoma tissues. Real-time polymerase chain reaction, Western blot, and other molecular biology methods were used to explore the role of KDM2A in colorectal adenocarcinoma cells. In this study, we report that the expression level of KDM2A is high in colorectal adenocarcinoma tissues, and this high expression promotes the proliferation and colony formation of colorectal adenocarcinoma cells, as demonstrated by KDM2A knockdown experiments. In addition, the expression of KDM2A is closely associated with cyclin D1 expression in colorectal adenocarcinoma tissues and cell lines. Our study reveals a novel role for high-expressed KDM2A in colorectal adenocarcinoma cell growth, and that the expression of KDM2A is associated with that of cyclin D1 in colorectal adenocarcinoma.

Active Component of Danshen (Salvia miltiorrhiza Bunge, Tanshinone I, Attenuates Lung Tumorigenesis via Inhibitions of VEGF, Cyclin A, and Cyclin B Expressions

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Yu-Tang Tung

2013-01-01

Full Text Available Tanshinone I (T1 and tanshinone II (T2 are the major diterpenes isolated from Danshen (Salvia miltiorrhiza Bunge. Three human lung adenocarcinoma cell lines, A549, CL1-0, and CL1-5, were treated with T1 and T2 for the in vitro antitumor test. Results showed that T1 was more effective than T2 in inhibiting the growth of lung cancer cells via suppressing the expression of VEGF, Cyclin A, and Cyclin B proteins in a dose-dependent manner. Moreover, a transgenic mice model of the human vascular endothelial growth factor-A165 (hVEGF-A165 gene-induced pulmonary tumor was further treated with T1 for the in vivo lung cancer therapy test. T1 significantly attenuated hVEGF-A165 overexpression to normal levels of the transgenic mice (Tg that were pretreated with human monocytic leukemia THP-1 cell-derived conditioned medium (CM. It also suppressed the formation of lung adenocarcinoma tumors (16.7% compared with two placebo groups (50% for Tg/Placebo and 83.3% for Tg/CM/Placebo; P<0.01. This antitumor effect is likely to slow the progression of cells through the S and G2/M phases of the cell cycle. Blocking of the tumor-activated cell cycle pathway may be a critical mechanism for the observed antitumorigenic effects of T1 treatment on vasculogenesis and angiogenesis.

Human T-cell leukemia virus type 1 Tax and cell cycle progression: role of cyclin D-cdk and p110Rb.

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Neuveut, C; Low, K G; Maldarelli, F; Schmitt, I; Majone, F; Grassmann, R; Jeang, K T

1998-06-01

Human T-cell leukemia virus type 1 is etiologically linked to the development of adult T-cell leukemia and various human neuropathies. The Tax protein of human T-cell leukemia virus type I has been implicated in cellular transformation. Like other oncoproteins, such as Myc, Jun, and Fos, Tax is a transcriptional activator. How it mechanistically dysregulates the cell cycle is unclear. Previously, it was suggested that Tax affects cell-phase transition by forming a direct protein-protein complex with p16(INK4a), thereby inactivating an inhibitor of G1-to-S-phase progression. Here we show that, in T cells deleted for p16(INK4a), Tax can compel an egress of cells from G0/G1 into S despite the absence of serum. We also show that in undifferentiated myocytes, expression of Tax represses cellular differentiation. In both settings, Tax expression was found to increase cyclin D-cdk activity and to enhance pRb phosphorylation. In T cells, a Tax-associated increase in steady-state E2F2 protein was also documented. In searching for a molecular explanation for these observations, we found that Tax forms a protein-protein complex with cyclin D3, whereas a point-mutated and transcriptionally inert Tax mutant failed to form such a complex. Interestingly, expression of wild-type Tax protein in cells was also correlated with the induction of a novel hyperphosphorylated cyclin D3 protein. Taken together, these findings suggest that Tax might directly influence cyclin D-cdk activity and function, perhaps by a route independent of cdk inhibitors such as p16(INK4a).

Effects of prostratin on Cyclin T1/P-TEFb function and the gene expression profile in primary resting CD4+ T cells

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Rice Andrew P

2006-10-01

Full Text Available Abstract Background The latent reservoir of human immunodeficiency virus type 1 (HIV-1 in resting CD4+ T cells is a major obstacle to the clearance of infection by highly active antiretroviral therapy (HAART. Recent studies have focused on searches for adjuvant therapies to activate this reservoir under conditions of HAART. Prostratin, a non tumor-promoting phorbol ester, is a candidate for such a strategy. Prostratin has been shown to reactivate latent HIV-1 and Tat-mediated transactivation may play an important role in this process. We examined resting CD4+ T cells from healthy donors to determine if prostratin induces Cyclin T1/P-TEFb, a cellular kinase composed of Cyclin T1 and Cyclin-dependent kinase-9 (CDK9 that mediates Tat function. We also examined effects of prostratin on Cyclin T2a, an alternative regulatory subunit for CDK9, and 7SK snRNA and the HEXIM1 protein, two factors that associate with P-TEFb and repress its kinase activity. Results Prostratin up-regulated Cyclin T1 protein expression, modestly induced CDK9 protein expression, and did not affect Cyclin T2a protein expression. Although the kinase activity of CDK9 in vitro was up-regulated by prostratin, we observed a large increase in the association of 7SK snRNA and the HEXIM1 protein with CDK9. Using HIV-1 reporter viruses with and without a functional Tat protein, we found that prostratin stimulation of HIV-1 gene expression appears to require a functional Tat protein. Microarray analyses were performed and several genes related to HIV biology, including APOBEC3B, DEFA1, and S100 calcium-binding protein genes, were found to be regulated by prostratin. Conclusion Prostratin induces Cyclin T1 expression and P-TEFb function and this is likely to be involved in prostratin reactivation of latent HIV-1 proviruses. The large increase in association of 7SK and HEXIM1 with P-TEFb following prostratin treatment may reflect a requirement in CD4+ T cells for a precise balance between

Cyclin D3 interacts with human activating transcription factor 5 and potentiates its transcription activity

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Liu Wenjin; Sun Maoyun; Jiang Jianhai; Shen Xiaoyun; Sun Qing; Liu Weicheng; Shen Hailian; Gu Jianxin

2004-01-01

The Cyclin D3 protein is a member of the D-type cyclins. Besides serving as cell cycle regulators, D-type cyclins have been reported to be able to interact with several transcription factors and modulate their transcriptional activations. Here we report that human activating transcription factor 5 (hATF5) is a new interacting partner of Cyclin D3. The interaction was confirmed by in vivo coimmunoprecipitation and in vitro binding analysis. Neither interaction between Cyclin D1 and hATF5 nor interaction between Cyclin D2 and hATF5 was observed. Confocal microscopy analysis showed that Cyclin D3 could colocalize with hATF5 in the nuclear region. Cyclin D3 could potentiate hATF5 transcriptional activity independently of its Cdk4 partner. But Cyclin D1 and Cyclin D2 had no effect on hATF5 transcriptional activity. These data provide a new clue to understand the new role of Cyclin D3 as a transcriptional regulator

Automated image analysis of cyclin D1 protein expression in invasive lobular breast carcinoma provides independent prognostic information.

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Tobin, Nicholas P; Lundgren, Katja L; Conway, Catherine; Anagnostaki, Lola; Costello, Sean; Landberg, Göran

2012-11-01

The emergence of automated image analysis algorithms has aided the enumeration, quantification, and immunohistochemical analyses of tumor cells in both whole section and tissue microarray samples. To date, the focus of such algorithms in the breast cancer setting has been on traditional markers in the common invasive ductal carcinoma subtype. Here, we aimed to optimize and validate an automated analysis of the cell cycle regulator cyclin D1 in a large collection of invasive lobular carcinoma and relate its expression to clinicopathologic data. The image analysis algorithm was trained to optimally match manual scoring of cyclin D1 protein expression in a subset of invasive lobular carcinoma tissue microarray cores. The algorithm was capable of distinguishing cyclin D1-positive cells and illustrated high correlation with traditional manual scoring (κ=0.63). It was then applied to our entire cohort of 483 patients, with subsequent statistical comparisons to clinical data. We found no correlation between cyclin D1 expression and tumor size, grade, and lymph node status. However, overexpression of the protein was associated with reduced recurrence-free survival (P=.029), as was positive nodal status (Pinvasive lobular carcinoma. Finally, high cyclin D1 expression was associated with increased hazard ratio in multivariate analysis (hazard ratio, 1.75; 95% confidence interval, 1.05-2.89). In conclusion, we describe an image analysis algorithm capable of reliably analyzing cyclin D1 staining in invasive lobular carcinoma and have linked overexpression of the protein to increased recurrence risk. Our findings support the use of cyclin D1 as a clinically informative biomarker for invasive lobular breast cancer. Copyright © 2012 Elsevier Inc. All rights reserved.

Insulin Promotes the Proliferation of Human Umbilical Cord Matrix-Derived Mesenchymal Stem Cells by Activating the Akt-Cyclin D1 Axis

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Peng Li

2017-01-01

Full Text Available Background. The functions of insulin in mesenchymal stem cells (MSC remain poorly understood. Methods. MSC from human umbilical cord matrix (UCM cultured in serum-free media (SFM with or without insulin were subjected to various molecular biological analyses to determine their proliferation and growth states, expression levels of Akt-cyclin D1 signaling molecules, and in vitro differentiation capacities. Results. Insulin accelerated the G1-S cell cycle progression of UCM-MSC and significantly stimulated their proliferation and growth in SFM. The pro-proliferative action of insulin was associated with augmented cyclin D1 and phosphorylated Akt expression levels. Akt inactivation remarkably abrogated insulin-induced increases in cyclin D1 expression and cell proliferation, indicating that insulin enhances the proliferation of UCM-MSC via acceleration of the G1-S transition mediated by the Akt-cyclin D1 pathway. Additionally, the UCM-MSC propagated in SFM supplemented with insulin exhibited similar specific surface antigen profiles and differentiation capacities as those generated in conventional media containing fetal bovine serum. Conclusions. These findings suggest that insulin acts solely to promote UCM-MSC proliferation without affecting their immunophenotype and differentiation potentials and thus have important implications for utilizing insulin to expand clinical-grade MSC in vitro.

CyclinD1, CDK4, and P21 expression by IEC-6 cells in response to NiTi alloy and polymeric biomaterials

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Wang, Zhanhui; Yan, Jun; Zheng, Qi; Wang, Zhigang

2012-01-01

In order to investigate how cells recognize biomaterials, mRNA that was expressed in attached Intestinal epithelial cells (IEC-6) on various suture substrates was evaluated. The expressed cell cycle regulators (cyclin D1, CDK4 and p21) mRNA were then isolated and detected using the real time- polymerase chain reaction (PCR) method. As a result, cyclin D1 gene expression was affected by cell-polymer adhesion and was associated with cell proliferation. In addition, CDK4 gene expression was affected by cell proliferation rather than by cell-biomaterial interaction. The p21 mRNA gene expression was higher in cells on more hydrophilic surfaces than on hydrophobic surfaces. Further, the cyclin D1, CDK4 and p21 gene expression were also influenced by the surface chemistry of suture materials. We concluded that the expression of cyclin D1, CDK4 and p21 mRNA was a powerful method for studying cell-biomaterial interactions or the evaluation of the carcinogenic activity of biomaterials. - Highlights: ►We evaluated the effects of biomaterials on the cyclin D1, CDK4 and p21 expression. ►Cell-polymer adhesion and cell proliferation affected cyclin D1 and CDK4 expression. ►The p21 expression was higher on more hydrophilic surfaces than on hydrophobic. ►They were also influenced by surface chemistry of biomaterials.

Cyclin-dependent kinase 5 regulates degranulation in human eosinophils.

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Odemuyiwa, Solomon O; Ilarraza, Ramses; Davoine, Francis; Logan, Michael R; Shayeganpour, Anooshirvan; Wu, Yingqi; Majaesic, Carina; Adamko, Darryl J; Moqbel, Redwan; Lacy, Paige

2015-04-01

Degranulation from eosinophils in response to secretagogue stimulation is a regulated process that involves exocytosis of granule proteins through specific signalling pathways. One potential pathway is dependent on cyclin-dependent kinase 5 (Cdk5) and its effector molecules, p35 and p39, which play a central role in neuronal cell exocytosis by phosphorylating Munc18, a regulator of SNARE binding. Emerging evidence suggests a role for Cdk5 in exocytosis in immune cells, although its role in eosinophils is not known. We sought to examine the expression of Cdk5 and its activators in human eosinophils, and to assess the role of Cdk5 in eosinophil degranulation. We used freshly isolated human eosinophils and analysed the expression of Cdk5, p35, p39 and Munc18c by Western blot, RT-PCR, flow cytometry and immunoprecipitation. Cdk5 kinase activity was determined following eosinophil activation. Cdk5 inhibitors were used (roscovitine, AT7519 and small interfering RNA) to determine its role in eosinophil peroxidase (EPX) secretion. Cdk5 was expressed in association with Munc18c, p35 and p39, and phosphorylated following human eosinophil activation with eotaxin/CCL11, platelet-activating factor, and secretory IgA-Sepharose. Cdk5 inhibitors (roscovitine, AT7519) reduced EPX release when cells were stimulated by PMA or secretory IgA. In assays using small interfering RNA knock-down of Cdk5 expression in human eosinophils, we observed inhibition of EPX release. Our findings suggest that in activated eosinophils, Cdk5 is phosphorylated and binds to Munc18c, resulting in Munc18c release from syntaxin-4, allowing SNARE binding and vesicle fusion, with subsequent eosinophil degranulation. Our work identifies a novel role for Cdk5 in eosinophil mediator release by agonist-induced degranulation. © 2014 John Wiley & Sons Ltd.

Therapeutic effects of lentivirus-mediated shRNA targeting of cyclin D1 in human gastric cancer

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Seo, Jin-Hee; Jeong, Eui-Suk; Choi, Yang-Kyu

2014-01-01

Gastric cancer is the second most common cause of cancer-related death in males and the fourth in females. Traditional treatment has poor prognosis because of recurrence and systemic side effects. Therefore, the development of new therapeutic strategies is an important issue. Lentivirus-mediated shRNA stably inhibits target genes and can efficiently transduce most cells. Since overexpressed cyclin D1 is closely related to human gastric cancer progression, inhibition of cyclin D1 using specific targeting could be an effective treatment method of human gastric cancer. The therapeutic effect of lentivirus-mediated shRNA targeting of cyclin D1 (ShCCND1) was analyzed both in vitro and in vivo experiments. In vitro, NCI-N87 cells with downregulation of cyclin D1 by ShCCND1 showed significant inhibition of cell proliferation, cell motility, and clonogenicity. Downregulation of cyclin D1 in NCI-N87 cells also resulted in significantly increased G1 arrest and apoptosis. In vivo, stable NCI-N87 cells expressing ShCCND1 were engrafted into nude mice. Then, the cancer-growth inhibition effect of lentivirus was confirmed. To assess lentivirus including ShCCND1 as a therapeutic agent, intratumoral injection was conducted. Tumor growth of the lentivirus-treated group was significantly inhibited compared to growth of the control group. These results are in accordance with the in vitro data and lend support to the mitotic figure count and apoptosis analysis of the tumor mass. The lentivirus-mediated ShCCND1 was constructed, which effectively inhibited growth of NCI-N87-derived cancer both in vitro and in vivo. The efficiency of shRNA knockdown and variation in the degree of inhibition is mediated by different shRNA sequences and cancer cell lines. These experimental results suggest the possibility of developing new gastric cancer therapies using lentivirus-mediated shRNA

The expression status of TRX, AR, and cyclin D1 correlates with clinicopathological characteristics and ER status in breast cancer.

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Huang, Weisun; Nie, Weiwei; Zhang, Wenwen; Wang, Yanru; Zhu, Aiyu; Guan, Xiaoxiang

2016-01-01

The ER signaling pathway plays a critical role in breast cancer. ER signaling pathway-related proteins, such as TRX, AR, and cyclin D1, may have an important function in breast cancer. However, the ways that they influence breast cancer development and progression are still unclear. A total of 101 Chinese female patients diagnosed with invasive ductal breast adenocarcinoma were retrospectively enrolled in the study. The expression levels of TRX, AR, and cyclin D1 were detected by immunohistochemistry and analyzed via correlation with clinicopathological characteristics and the expression status of ER, PR, and HER2. The expression status of TRX, AR, and cyclin D1 was not associated with the patient's age, menopausal status, tumor size, or histological differentiation (P>0.05), but was positively correlated with ER and PR (PTRX-positive patients were also HER2-positive (P=0.003). Of AR- or cyclin D1-positive patients, most had relatively earlier I-II tumor stage (P=0.005 and P=0.047, respectively) and no metastatic lymph node involvement (P=0.008 and P=0.005, respectively). TRX was found to be positively correlated with ER and PR expression, whereas it was negatively correlated with HER2 expression. In addition, we found that the positive expression of AR and cyclin D1 was correlated with lower TNM stage and fewer metastatic lymph nodes, and it was more common in ER-positive breast cancer than in the basal-like subtype. This may indicate that AR and cyclin D1 are good predictive and prognostic factors and closely interact with ER signaling pathway. Further studies will be necessary to investigate the response and clinical outcomes of treatment targeting TRX, AR, and cyclin D1.

Human amniotic fluid stem cells (hAFSCs expressing p21 and cyclin D1 genes retain excellent viability after freezing with (dimethyl sulfoxide DMSO

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Shiva Gholizadeh-Ghaleh Aziz

2018-04-01

Full Text Available Human amniotic fluid stem cells (hAFSCs have features intermediate between embryonic and adult SCs, can differentiate into lineages of all three germ layers, and do not develop into tumors in vivo. Moreover, hAFSCs can be easily obtained in routine procedures and there is no ethical or legal limitations regarding their use for clinical and experimental applications. The aim of this study was to assess the effect of slow freezing/thawing and two different concentrations of DMSO (10% DMSO + 90% fetal bovine serum [FBS] and 5% DMSO + 95% FBS on the survival of hAFSCs. hAFSCs were obtained from 5 pregnant women during amniocentesis at 16–22 weeks of gestation. The expression of pluripotency markers (Octamer-binding transcription factor 4 [Oct4] and NANOG by reverse transcription polymerase chain reaction and cell surface markers (cluster of differentiation [CD31], CD44, CD45, and CD90 by flow cytometry was analyzed before and after the slow-freezing. Cell viability was assessed by trypan blue exclusion or MTT assay. Quantitative mRNA expression of Oct4, NANOG, cyclin D1 and p21 was determined by real-time PCR before and after the slow-freezing. Pluripotency of hAFSCs was confirmed by NANOG and POU5F1 (Oct4 gene expression before and after slow-freezing. All hAFSC cultures were positive for CD44 and CD90. A higher viability of hAFSCs was observed after freezing with 90% FBS + 10% DMSO. There was increased expression of NANOG and decreased expression of POU5F1 gene after freezing, compared to control cells (before freezing. DMSO and the process of freezing did not significantly change the expression of p21 and cyclin D1 genes in hAFSCs. Overall, our results indicate the applicability of slow-freezing and DMSO in cryopreservation of SCs.

Misexpression of cyclin B3 leads to aberrant spermatogenesis.

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Refik-Rogers, Jale; Manova, Katia; Koff, Andrew

2006-09-01

Mus musculus cyclin B3 is an early meiotic cyclin that is expressed in leptotene and zygotene phases during gametogenesis. In order to determine whether downregulation of cyclin B3 at zygotene-pachytene transition was important for normal spermatogenesis, we investigated the consequences of expressing H. sapiens cyclin B3 after zygotene in mouse testes. Prolonging expression of cyclin B3 until the end of meiosis led to a reduction in sperm counts and disruption of spermatogenesis in four independent lines of transgenic mice. There were three distinct morphological defects associated with the ectopic expression of cyclin B3. Seminiferous tubules were either depleted of germ cells, had an abnormal cell mass in the lumen, or were characterized by the presence of abnormal round spermatids. These defects were associated with increased apoptosis in the testes. These results suggest that downregulation of cyclin B3 at the zygotene-pachytene transition is required to ensure normal spermatogenesis.

Glucose Regulates Cyclin D2 Expression in Quiescent and Replicating Pancreatic β-Cells Through Glycolysis and Calcium Channels

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Salpeter, Seth J.; Klochendler, Agnes; Weinberg-Corem, Noa; Porat, Shay; Granot, Zvi; Shapiro, A. M. James; Magnuson, Mark A.; Eden, Amir; Grimsby, Joseph; Glaser, Benjamin

2011-01-01

Understanding the molecular triggers of pancreatic β-cell proliferation may facilitate the development of regenerative therapies for diabetes. Genetic studies have demonstrated an important role for cyclin D2 in β-cell proliferation and mass homeostasis, but its specific function in β-cell division and mechanism of regulation remain unclear. Here, we report that cyclin D2 is present at high levels in the nucleus of quiescent β-cells in vivo. The major regulator of cyclin D2 expression is glucose, acting via glycolysis and calcium channels in the β-cell to control cyclin D2 mRNA levels. Furthermore, cyclin D2 mRNA is down-regulated during S-G2-M phases of each β-cell division, via a mechanism that is also affected by glucose metabolism. Thus, glucose metabolism maintains high levels of nuclear cyclin D2 in quiescent β-cells and modulates the down-regulation of cyclin D2 in replicating β-cells. These data challenge the standard model for regulation of cyclin D2 during the cell division cycle and suggest cyclin D2 as a molecular link between glucose levels and β-cell replication. PMID:21521747

Negative effect of cyclin D1 overexpression on recurrence-free survival in stage II-IIIA lung adenocarcinoma and its expression modulation by vorinostat in vitro.

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Lee, Eunju; Jin, DongHao; Lee, Bo Bin; Kim, Yujin; Han, Joungho; Shim, Young Mog; Kim, Duk-Hwan

2015-12-17

This study was aimed at identifying prognostic biomarkers for stage II-IIIA non-small cell lung cancer (NSCLC) according to histology and at investigating the effect of vorinostat on the expression of these biomarkers. Expression levels of cyclin D1, cyclin A2, cyclin E, and p16 proteins that are involved in the G1-to-S phase progression of cell cycle were analyzed using immunohistochemistry in formalin-fixed paraffin-embedded tissues from 372 samples of stage II-IIIA NSCLC. The effect of vorinostat on the expression of these proteins, impacts on cell cycle, and histone modification was explored in lung cancer cells. Abnormal expression of cyclin A2, cyclin D1, cyclin E, and p16 was found in 66, 47, 34, and 51 % of 372 cases, respectively. Amongst the four proteins, only cyclin D1 overexpression was significantly associated with poor recurrence-free survival (adjusted hazard ratio = 1.87; 95 % confidence interval = 1.12 - 2.69, P = 0.02) in adenocarcinoma but not in squamous cell carcinoma (P = 0.44). Vorinostat inhibited cell cycle progression to the S-phase and induced down-regulation of cyclin D1 in vitro. The down-regulation of cyclin D1 by vorinostat was comparable to a siRNA-mediated knockdown of cyclin D1 in A549 cells, but vorinostat in the presence of benzo[a]pyrene showed a differential effect in different lung cancer cell lines. Cyclin D1 down-regulation by vorinostat was associated with the accumulation of dimethyl-H3K9 at the promoter of the gene. The present study suggests that cyclin D1 may be an independent prognostic factor for recurrence-free survival in stage II-IIIA adenocarcinoma of lung and its expression may be modulated by vorinostat.

C/EBP{delta} targets cyclin D1 for proteasome-mediated degradation via induction of CDC27/APC3 expression.

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Pawar, Snehalata A; Sarkar, Tapasree Roy; Balamurugan, Kuppusamy; Sharan, Shikha; Wang, Jun; Zhang, Youhong; Dowdy, Steven F; Huang, A-Mei; Sterneck, Esta

2010-05-18

The transcription factor CCAAT/enhancer binding protein delta (C/EBPdelta, CEBPD, NFIL-6beta) has tumor suppressor function; however, the molecular mechanism(s) by which C/EBPdelta exerts its effect are largely unknown. Here, we report that C/EBPdelta induces expression of the Cdc27 (APC3) subunit of the anaphase promoting complex/cyclosome (APC/C), which results in the polyubiquitination and degradation of the prooncogenic cell cycle regulator cyclin D1, and also down-regulates cyclin B1, Skp2, and Plk-1. In C/EBPdelta knockout mouse embryo fibroblasts (MEF) Cdc27 levels were reduced, whereas cyclin D1 levels were increased even in the presence of activated GSK-3beta. Silencing of C/EBPdelta, Cdc27, or the APC/C coactivator Cdh1 (FZR1) in MCF-10A breast epithelial cells increased cyclin D1 protein expression. Like C/EBPdelta, and in contrast to cyclin D1, Cdc27 was down-regulated in several breast cancer cell lines, suggesting that Cdc27 itself may be a tumor suppressor. Cyclin D1 is a known substrate of polyubiquitination complex SKP1/CUL1/F-box (SCF), and our studies show that Cdc27 directs cyclin D1 to alternative degradation by APC/C. These findings shed light on the role and regulation of APC/C, which is critical for most cellular processes.

Six1 promotes proliferation of pancreatic cancer cells via upregulation of cyclin D1 expression.

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Zhaoming Li

Full Text Available Six1 is one of the transcription factors that act as master regulators of development and are frequently dysregulated in cancers. However, the role of Six1 in pancreatic cancer is not clear. Here we show that the relative expression of Six1 mRNA is increased in pancreatic cancer and correlated with advanced tumor stage. In vitro functional assays demonstrate that forced overexpression of Six1 significantly enhances the growth rate and proliferation ability of pancreatic cancer cells. Knockdown of endogenous Six1 decreases the proliferation of these cells dramatically. Furthermore, Six1 promotes the growth of pancreatic cancer cells in a xenograft assay. We also show that the gene encoding cyclin D1 is a direct transcriptional target of Six1 in pancreatic cancer cells. Overexpression of Six1 upregulates cyclin D1 mRNA and protein, and significantly enhances the activity of the cyclin D1 promoter in PANC-1 cells. We demonstrate that Six1 promotes cell cycle progression and proliferation by upregulation of cyclin D1. These data suggest that Six1 is overexpressed in pancreatic cancer and may contribute to the increased cell proliferation through upregulation of cyclin D1.

Vitex rotundifolia Fruit Suppresses the Proliferation of Human Colorectal Cancer Cells through Down-regulation of Cyclin D1 and CDK4 via Proteasomal-Dependent Degradation and Transcriptional Inhibition.

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Song, Hun Min; Park, Gwang Hun; Park, Su Bin; Kim, Hyun-Seok; Son, Ho-Jun; Um, Yurry; Jeong, Jin Boo

2018-01-01

Viticis Fructus (VF) as the dried fruit from Vitex rotundifolia L. used as a traditional medicine for treating inflammation, headache, migraine, chronic bronchitis, eye pain, and gastrointestinal infections has been reported to have antiproliferative effects against various cancer cells, including breast, lung and colorectal cancer cells. However, the molecular mechanisms by which VF mediates the inhibitory effect of the proliferation of cancer cells have not been elucidated in detail. In this study, we investigated the molecular mechanism of VF on the down-regulation of cyclin D1 and CDK4 level associated with cancer cell proliferation. VF suppressed the proliferation of human colorectal cancer cell lines such as HCT116 and SW480. VF induced decrease in cyclin D1 and CDK4 in both protein and mRNA levels. However, the protein levels of cyclin D1 and CDK4 were decreased by VF at an earlier time than the change of mRNA levels; rather it suppressed the expression of cyclin D1 and CDK4 via the proteasomal degradation. In cyclin D1 and CDK4 degradation, we found that Thr286 phosphorylation of cyclin D1 plays a pivotal role in VF-mediated cyclin D1 degradation. Subsequent experiments with several kinase inhibitors suggest that VF-mediated degradation of cyclin D1 may be dependent on GSK3[Formula: see text] and VF-mediated degradation of CDK4 is dependent on ERK1/2, p38 and GSK3[Formula: see text]. In the transcriptional regulation of cyclin D1 and CDK4, we found that VF inhibited Wnt activation associated with cyclin D1 transcriptional regulation through TCF4 down-regulation. In addition, VF treatment down-regulated c-myc expression associated CDK4 transcriptional regulation. Our results suggest that VF has potential to be a candidate for the development of chemoprevention or therapeutic agents for human colorectal cancer.

CARMA3 is overexpressed in colon cancer and regulates NF-κB activity and cyclin D1 expression

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Miao, Zhifeng; Zhao, Tingting; Wang, Zhenning; Xu, Yingying; Song, Yongxi; Wu, Jianhua; Xu, Huimian

2012-01-01

Highlights: ► CARMA3 expression is elevated in colon cancers. ► CARMA3 promotes proliferation and cell cycle progression in colon cancer cells. ► CARMA3 upregulates cyclinD1 through NF-κB activation. -- Abstract: CARMA3 was recently reported to be overexpressed in cancers and associated with the malignant behavior of cancer cells. However, the expression of CARMA3 and its biological roles in colon cancer have not been reported. In the present study, we analyzed the expression pattern of CARMA3 in colon cancer tissues and found that CARMA3 was overexpressed in 30.8% of colon cancer specimens. There was a significant association between CARMA3 overexpression and TNM stage (p = 0.0383), lymph node metastasis (p = 0.0091) and Ki67 proliferation index (p = 0.0035). Furthermore, knockdown of CARMA3 expression in HT29 and HCT116 cells with high endogenous expression decreased cell proliferation and cell cycle progression while overexpression of CARMA3 in LoVo cell line promoted cell proliferation and facilitated cell cycle transition. Further analysis showed that CARMA3 knockdown downregulated and its overexpression upregulated cyclin D1 expression and phospho-Rb levels. In addition, we found that CARMA3 depletion inhibited p-IκB levels and NF-κB activity and its overexpression increased p-IκB expression and NF-κB activity. NF-κB inhibitor BAY 11-7082 reversed the role of CARMA3 on cyclin D1 upregulation. In conclusion, our study found that CARMA3 is overexpressed in colon cancers and contributes to malignant cell growth by facilitating cell cycle progression through NF-κB mediated upregulation of cyclin D1.

c-Jun/AP-1 pathway-mediated cyclin D1 expression participates in low dose arsenite-induced transformation in mouse epidermal JB6 Cl41 cells

International Nuclear Information System (INIS)

Zhang Dongyun; Li Jingxia; Gao Jimin; Huang Chuanshu

2009-01-01

Arsenic is a well-documented human carcinogen associated with skin carcinogenesis. Our previous work reveals that arsenite exposure is able to induce cell transformation in mouse epidermal cell JB6 Cl41 through the activation of ERK, rather than JNK pathway. Our current studies further evaluate downstream pathway in low dose arsenite-induced cell transformation in JB6 Cl41 cells. Our results showed that treatment of cells with low dose arsenite induced activation of c-Jun/AP-1 pathway, and ectopic expression of dominant negative mutant of c-Jun (TAM67) blocked arsenite-induced transformation. Furthermore, our data indicated that cyclin D1 was an important downstream molecule involved in c-Jun/AP-1-mediated cell transformation upon low dose arsenite exposure, because inhibition of cyclin D1 expression by its specific siRNA in the JB6 Cl41 cells resulted in impairment of anchorage-independent growth of cells induced by low dose arsenite. Collectively, our results demonstrate that c-Jun/AP-1-mediated cyclin D1 expression is at least one of the key events implicated in cell transformation upon low dose arsenite exposure

Restrictions in cell cycle progression of adult vestibular supporting cells in response to ectopic cyclin D1 expression.

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Heidi Loponen

Full Text Available Sensory hair cells and supporting cells of the mammalian inner ear are quiescent cells, which do not regenerate. In contrast, non-mammalian supporting cells have the ability to re-enter the cell cycle and produce replacement hair cells. Earlier studies have demonstrated cyclin D1 expression in the developing mouse supporting cells and its downregulation along maturation. In explant cultures of the mouse utricle, we have here focused on the cell cycle control mechanisms and proliferative potential of adult supporting cells. These cells were forced into the cell cycle through adenoviral-mediated cyclin D1 overexpression. Ectopic cyclin D1 triggered robust cell cycle re-entry of supporting cells, accompanied by changes in p27(Kip1 and p21(Cip1 expressions. Main part of cell cycle reactivated supporting cells were DNA damaged and arrested at the G2/M boundary. Only small numbers of mitotic supporting cells and rare cells with signs of two successive replications were found. Ectopic cyclin D1-triggered cell cycle reactivation did not lead to hyperplasia of the sensory epithelium. In addition, a part of ectopic cyclin D1 was sequestered in the cytoplasm, reflecting its ineffective nuclear import. Combined, our data reveal intrinsic barriers that limit proliferative capacity of utricular supporting cells.

Restrictions in cell cycle progression of adult vestibular supporting cells in response to ectopic cyclin D1 expression.

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Loponen, Heidi; Ylikoski, Jukka; Albrecht, Jeffrey H; Pirvola, Ulla

2011-01-01

Sensory hair cells and supporting cells of the mammalian inner ear are quiescent cells, which do not regenerate. In contrast, non-mammalian supporting cells have the ability to re-enter the cell cycle and produce replacement hair cells. Earlier studies have demonstrated cyclin D1 expression in the developing mouse supporting cells and its downregulation along maturation. In explant cultures of the mouse utricle, we have here focused on the cell cycle control mechanisms and proliferative potential of adult supporting cells. These cells were forced into the cell cycle through adenoviral-mediated cyclin D1 overexpression. Ectopic cyclin D1 triggered robust cell cycle re-entry of supporting cells, accompanied by changes in p27(Kip1) and p21(Cip1) expressions. Main part of cell cycle reactivated supporting cells were DNA damaged and arrested at the G2/M boundary. Only small numbers of mitotic supporting cells and rare cells with signs of two successive replications were found. Ectopic cyclin D1-triggered cell cycle reactivation did not lead to hyperplasia of the sensory epithelium. In addition, a part of ectopic cyclin D1 was sequestered in the cytoplasm, reflecting its ineffective nuclear import. Combined, our data reveal intrinsic barriers that limit proliferative capacity of utricular supporting cells.

[Relationship between the expression of beta-cat, cyclin D1 and c-myc and the occurance and biological behavior of pancreatic cancer].

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Li, Yu-jun; Ji, Xiang-rui

2003-06-01

To study the relationship between the abnormal expression of beta-catenin (beta-cat) and the high expressions of cyclin D1 and c-myc and the occurance, proliferation, infiltration, metastasis and prognosis of pancreatic cancer, and to provide rational basis for the clinical diagnosis and treatment. Immunohistochemical PicTure trade mark was used to examine the expressions of beta-cat, cyclin D1 and c-myc in 47 cases of the cancerous tissue of pancreas, 12 cases of the pancreatic intraepithelial neoplasia and 10 cases of normal tissue of pancreas, respectively. Pancreatic cancer proliferation cell nuclear antigen (PCNA) was also tested as the index of the extent of proliferation of the pancreatic cancer. beta-cat was expressed normally in the 10 cases of the normal pancreatic tissue, while cyclin D1 and c-myc were negative. The expression rates of beta-cat, cyclin D1 and c-myc in the tissues of the pancreatic intraepithelial neoplasia and the pancreatic cancer had no significant difference [6/12 and 68.1% (32/47), 6/12 and 74.5% (35/47), 5/12 and 70.2% (33/47) respectively;P values were all more than 0.05]. The abnormal expression rate of beta-cat was significantly correlated to the metastasis of the pancreatic cancer and the one-year survival rate (both P 0.05). The expression rate of cyclin D1 was correlated with the proliferation of the pancreatic cancer and the extent of differentiation (both P 0.05). The expression rate of c-myc was not correlated with the size, the extent of proliferation, infiltration, metastasis, or one-year survival rate (both P > 0.05), but closely with the proliferation activity of the cancerous tissue of pancreas (P < 0.05). The abnormal expression of beta-cat and the high expressions of cyclin D1 and c-myc had a parallel relationship with the pancreatic intraepithelial neoplasia and pancreatic cancer (both P < 0.05, gamma = 1.000, 0.845, 0.437, 0.452). The abnormal expression of beta-cat activates cyclin D1 and c-myc, and results in the

Rb and FZR1/Cdh1 determine CDK4/6-cyclin D requirement in C. elegans and human cancer cells

NARCIS (Netherlands)

The, Inge; Ruijtenberg, Suzan; Bouchet, Benjamin P; Cristobal, Alba; Prinsen, Martine B W; van Mourik, Tim; Koreth, John; Xu, Huihong; Heck, Albert J R; Akhmanova, Anna; Cuppen, Edwin; Boxem, Mike; Muñoz, Javier; van den Heuvel, Sander

2015-01-01

Cyclin-dependent kinases 4 and 6 (CDK4/6) in complex with D-type cyclins promote cell cycle entry. Most human cancers contain overactive CDK4/6-cyclin D, and CDK4/6-specific inhibitors are promising anti-cancer therapeutics. Here, we investigate the critical functions of CDK4/6-cyclin D kinases,

BmCyclin B and BmCyclin B3 are required for cell cycle progression in the silkworm, Bombyx mori.

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Pan, Minhui; Hong, Kaili; Chen, Xiangyun; Pan, Chun; Chen, Xuemei; Kuang, Xiuxiu; Lu, Cheng

2013-04-01

Cyclin B is an important regulator of the cell cycle G2 to M phase transition. The silkworm genomic database shows that there are two Cyclin B genes in the silkworm (Bombyx mori), BmCyclin B and BmCyclin B3. Using silkworm EST data, the cyclin B3 (EU074796) gene was cloned. Its complete cDNA was 1665 bp with an ORF of 1536 bp derived from seven exons and six introns. The BmCyclin B3 gene encodes 511 amino acids, and the predicted molecular weight is 57.8 kD with an isoelectric point of 9.18. The protein contains one protein damage box and two cyclin boxes. RNA interference-mediated reduction of BmCyclin B and BmCyclin B3 expression induced cell cycle arrest in G2 or M phase in BmN-SWU1 cells, thus inhibiting cell proliferation. These results suggest that BmCyclin B and BmCyclin B3 are necessary for completing the cell cycle in silkworm cells.

Cyclin D1 negatively regulates the expression of differentiation genes in HT-29 M6 mucus-secreting colon cancer cells.

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Mayo, Clara; Mayol, Xavier

2009-08-28

HT-29 M6 colon cancer cells differentiate to a mucus-secreting phenotype in culture. We found that the pattern of cyclin D1 expression in HT-29 M6 cells did not correlate with instances of cell proliferation but was specifically induced during a dedifferentiation process following disaggregation of epithelial cell layers, even under conditions that did not allow cell cycle reentrance. Interestingly, ectopic expression of cyclin D1 in differentiated cells led to the inhibition of the transcriptional activity of differentiation gene promoters, such as the mucin MUC1. We thus propose that the overexpression of cyclin D1 found in colon cancer favours tumour dedifferentiation as one mechanism of tumour progression.

High glucose concentration induces endothelial cell proliferation by regulating cyclin-D2-related miR-98.

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Li, Xin-Xin; Liu, Yue-Mei; Li, You-Jie; Xie, Ning; Yan, Yun-Fei; Chi, Yong-Liang; Zhou, Ling; Xie, Shu-Yang; Wang, Ping-Yu

2016-06-01

Cyclin D2 is involved in the pathology of vascular complications of type 2 diabetes mellitus (T2DM). This study investigated the role of cyclin-D2-regulated miRNAs in endothelial cell proliferation of T2DM. Results showed that higher glucose concentration (4.5 g/l) significantly promoted the proliferation of rat aortic endothelial cells (RAOECs), and significantly increased the expression of cyclin D2 and phosphorylation of retinoblastoma 1 (p-RB1) in RAOECs compared with those under low glucose concentration. The cyclin D2-3' untranslated region is targeted by miR-98, as demonstrated by miRNA analysis software. Western blot also confirmed that cyclin D2 and p-RB1 expression was regulated by miR-98. The results indicated that miR-98 treatment can induce RAOEC apoptosis. The suppression of RAOEC growth by miR-98 might be related to regulation of Bcl-2, Bax and Caspase 9 expression. Furthermore, the expression levels of miR-98 decreased in 4.5 g/l glucose-treated cells compared with those treated by low glucose concentration. Similarly, the expression of miR-98 significantly decreased in aortas of established streptozotocin (STZ)-induced diabetic rat model compared with that in control rats; but cyclin D2 and p-RB1 levels remarkably increased in aortas of STZ-induced diabetic rats compared with those in healthy control rats. In conclusion, this study demonstrated that high glucose concentration induces cyclin D2 up-regulation and miR-98 down-regulation in the RAOECs. By regulating cyclin D2, miR-98 can inhibit human endothelial cell growth, thereby providing novel therapeutic targets for vascular complication of T2DM. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Obatoclax, a Pan-BCL-2 Inhibitor, Targets Cyclin D1 for Degradation to Induce Antiproliferation in Human Colorectal Carcinoma Cells.

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Or, Chi-Hung R; Chang, Yachu; Lin, Wei-Cheng; Lee, Wee-Chyan; Su, Hong-Lin; Cheung, Muk-Wing; Huang, Chang-Po; Ho, Cheesang; Chang, Chia-Che

2016-12-27

Colorectal cancer is the third most common cancer worldwide. Aberrant overexpression of antiapoptotic BCL-2 (B-cell lymphoma 2) family proteins is closely linked to tumorigenesis and poor prognosis in colorectal cancer. Obatoclax is an inhibitor targeting all antiapoptotic BCL-2 proteins. A previous study has described the antiproliferative action of obatoclax in one human colorectal cancer cell line without elucidating the underlying mechanisms. We herein reported that, in a panel of human colorectal cancer cell lines, obatoclax inhibits cell proliferation, suppresses clonogenicity, and induces G₁-phase cell cycle arrest, along with cyclin D1 downregulation. Notably, ectopic cyclin D1 overexpression abrogated clonogenicity suppression but also G₁-phase arrest elicited by obatoclax. Mechanistically, pre-treatment with the proteasome inhibitor MG-132 restored cyclin D1 levels in all obatoclax-treated cell lines. Cycloheximide chase analyses further revealed an evident reduction in the half-life of cyclin D1 protein by obatoclax, confirming that obatoclax downregulates cyclin D1 through induction of cyclin D1 proteasomal degradation. Lastly, threonine 286 phosphorylation of cyclin D1, which is essential for initiating cyclin D1 proteasomal degradation, was induced by obatoclax in one cell line but not others. Collectively, we reveal a novel anticancer mechanism of obatoclax by validating that obatoclax targets cyclin D1 for proteasomal degradation to downregulate cyclin D1 for inducing antiproliferation.

Inhibition of Rac1 activity induces G1/S phase arrest through the GSK3/cyclin D1 pathway in human cancer cells.

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Liu, Linna; Zhang, Hongmei; Shi, Lei; Zhang, Wenjuan; Yuan, Juanli; Chen, Xiang; Liu, Juanjuan; Zhang, Yan; Wang, Zhipeng

2014-10-01

Rac1 has been shown to regulate the cell cycle in cancer cells. Yet, the related mechanism remains unclear. Thus, the present study aimed to investigate the mechanism involved in the regulation of G1/S phase transition by Rac1 in cancer cells. Inhibition of Rac1 by inhibitor NSC23766 induced G1/S phase arrest and inhibited the proliferation of A431, SW480 and U2-OS cells. Suppression of GSK3 by shRNA partially rescued G1/S phase arrest and inhibition of proliferation. Incubation of cells with NSC23766 reduced p-AKT and inactivated p-GSK3α and p-GSK3β, increased p-cyclin D1 expression and decreased the level of cyclin D1 protein. Consequently, cyclin D1 targeting transcriptional factor E2F1 expression, which promotes G1 to S phase transition, was also reduced. In contrast, constitutive active Rac1 resulted in increased p-AKT and inactivated p-GSK3α and p-GSK3β, decreased p-cyclin D1 expression and enhanced levels of cyclin D1 and E2F1 expression. Moreover, suppression of GSK3 did not alter p-AKT or Rac1 activity, but decreased p-cyclin D1 and increased total cyclin D1 protein. However, neither Rac1 nor GSK3 inhibition altered cyclin D1 at the RNA level. Moreover, after inhibition of Rac1 or GSK3 following proteasome inhibitor MG132 treatment, cyclin D1 expression at the protein level remained constant, indicating that Rac1 and GSK3 may regulate cyclin D1 turnover through phosphorylation and degradation. Therefore, our findings suggest that inhibition of Rac1 induces cell cycle G1/S arrest in cancer cells by regulation of the GSK3/cyclin D1 pathway.

Rising cyclin-CDK levels order cell cycle events.

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Catherine Oikonomou

Full Text Available Diverse mitotic events can be triggered in the correct order and time by a single cyclin-CDK. A single regulator could confer order and timing on multiple events if later events require higher cyclin-CDK than earlier events, so that gradually rising cyclin-CDK levels can sequentially trigger responsive events: the "quantitative model" of ordering.This 'quantitative model' makes predictions for the effect of locking cyclin at fixed levels for a protracted period: at low cyclin levels, early events should occur rapidly, while late events should be slow, defective, or highly variable (depending on threshold mechanism. We titrated the budding yeast mitotic cyclin Clb2 within its endogenous expression range to a stable, fixed level and measured time to occurrence of three mitotic events: growth depolarization, spindle formation, and spindle elongation, as a function of fixed Clb2 level. These events require increasingly more Clb2 according to their normal order of occurrence. Events occur efficiently and with low variability at fixed Clb2 levels similar to those observed when the events normally occur. A second prediction of the model is that increasing the rate of cyclin accumulation should globally advance timing of all events. Moderate (<2-fold overexpression of Clb2 accelerates all events of mitosis, resulting in consistently rapid sequential cell cycles. However, this moderate overexpression also causes a significant frequency of premature mitoses leading to inviability, suggesting that Clb2 expression level is optimized to balance the fitness costs of variability and catastrophe.We conclude that mitotic events are regulated by discrete cyclin-CDK thresholds. These thresholds are sequentially triggered as cyclin increases, yielding reliable order and timing. In many biological processes a graded input must be translated into discrete outputs. In such systems, expression of the central regulator is likely to be tuned to an optimum level, as we

The human HECA interacts with cyclins and CDKs to antagonize Wnt-mediated proliferation and chemoresistance of head and neck cancer cells

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Dowejko, Albert, E-mail: Albert.Dowejko@klinik.uni-regensburg.de [Department of Oral and Maxillofacial Surgery, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg (Germany); Bauer, Richard; Bauer, Karin [Department of Oral and Maxillofacial Surgery, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg (Germany); Mueller-Richter, Urs D.A. [Department of Oral and Maxillofacial Plastic Surgery, University of Wuerzburg, Pleicherwall 2, 97070 Wuerzburg (Germany); Reichert, Torsten E. [Department of Oral and Maxillofacial Surgery, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg (Germany)

2012-03-10

There is a growing evidence that the human homologue of the Drosophila headcase (HECA) plays an important role in human carcinogenesis. So far specific protein interaction partners and affected signaling pathways of HECA are still elusive. In a recent study we showed that HECA overexpression in oral squamous-cell carcinoma (OSCC) keratinocytes has tumor suppressive effects resulting in a recuperation of cell cycle control concerning the entry and progression of S-phase, G2- and M-phase. Currently, quantitative RT-PCR and immunohistochemical analysis of primary tumor tissue from OSCC patients demonstrate that HECA expression is markedly decreased compared to normal control patients with abundant HECA expression. Additionally, there is nearly no HECA expression in OSCC metastases. Here, we show that HECA expression is negatively controlled by the Wnt-pathway and TCF4, a Wnt related transcription factor, binds to the HECA promoter. Furthermore, immunocytochemistry reveals colocalization of HECA with the cyclin dependent kinase CDK9. Immunoprecipitation experiments and proximity ligation assays further reveal an interaction of HECA with CDK2, CDK9, Cyclin A and Cyclin K, a direct transcriptional target of the p53 tumor suppressor. Silencing HECA in OSCC cell lines leads to a significant increase of cell division and a markedly increased resistance against the chemotherapeutic cisplatin. On the contrary, HECA overexpressing OSCC cell lines show decreased resistance of OSCC cells against cisplatin. Therefore, HECA could be considered as future therapeutic agent against Wnt-dependent tumor progression. -- Highlights: Black-Right-Pointing-Pointer HECA is a new cell cycle regulator with anti-tumor features in head and neck cancer. Black-Right-Pointing-Pointer During tumor progression HECA mRNA and protein expression decrease. Black-Right-Pointing-Pointer The HECA promotor is a direct target of the Wnt/beta-catenin/TCF-pathway. Black-Right-Pointing-Pointer The HECA protein

Cyclin D1 overexpression, cell cycle progression and radiosensitivity in MBP cells

International Nuclear Information System (INIS)

Wu Lijun; Yu Zengliang

2000-11-01

Clones that exhibited a minimum of 7-8 fold cyclin D1 level above the parent cell lines or the vector control were obtained after transfected with the entire coding sequence of human 1.1 kb cyclin D1 cDNA. Studies showed that there was no significant difference in Radiosensitivity between over-expressing cyclin D1 and control cultures from either mouse or human origin. Using flow cytometry to access cell cycle distribution in the exponentially growth cultures of MCF10F-D1-21 and MCF10F-V-3, it was found that there was a 50 percent increase in the proportion of G2/M phase cells and 5.3 percent decrease in the proportion of G0/G1 phase cells in MCF10F-D1-21 comparing with MCF10F-V-3, though they were with the same proportion of cells in S phase

Expression of Flk-1 and Cyclin D2 mRNA in the Myocardium of Rats with Doxorubicin-Induced Cardiomyopathy and after Treatment with Betulonic Acid Amide.

Science.gov (United States)

Mzhelskaya, M M; Klinnikova, M G; Koldysheva, E V; Lushnikova, E L

2017-10-01

The expression of VEGFR2 (Flk-1, according to immunohistochemistry) and of cyclin D2 mRNA (according to real-time PCR) in the myocardium of rats is studied in doxorubicin-induced cardiomyopathy and in response to betulonic acid amide. Doxorubicin alone and in combination with betulonic acid amide causes after 3 days a manifest reduction of cyclin D2 mRNA expression (by 38 and 63%, respectively), while injection of betulonic acid amide alone causes a 23-fold increase of cyclin D2 mRNA expression. An increase of cyclin D2 mRNA expression has been detected in all experimental groups after 14 days of experiment, the most pronounced in response to betulonic acid amide (63 times). The expression of Flk-1 in cardiomyocytes increases significantly in response to both chemical agents starting from day 3 of experiment. These results indicate that doxorubicin and betulonic acid amide induce cytoprotective reactions in the myocardium, first at the intracellular, then at the cellular levels.

Hath1 inhibits proliferation of colon cancer cells probably through up-regulating expression of Muc2 and p27 and down-regulating expression of cyclin D1.

Science.gov (United States)

Zhu, Dai-Hua; Niu, Bai-Lin; Du, Hui-Min; Ren, Ke; Sun, Jian-Ming; Gong, Jian-Ping

2012-01-01

Previous studies showed that Math1 homologous to human Hath1 can cause mouse goblet cells to differentiate. In this context it is important that the majority of colon cancers have few goblet cells. In the present study, the potential role of Hath1 in colon carcinogenesis was investigated. Sections of paraffin-embedded tissues were used to investigate the goblet cell population of normal colon mucosa, mucosa adjacent colon cancer and colon cancer samples from 48 patients. Hath1 and Muc2 expression in these samples were tested by immunohistochemistry, quantitative real-time reverse transcription -PCR and Western blotting. After the recombinant plasmid, pcDNA3.1(+)-Hath1 had been transfected into HT29 colon cancer cells, three clones were selected randomly to test the levels of Hath1 mRNA, Muc2 mRNA, Hath1, Muc2, cyclin D1 and p27 by quantitative real-time reverse transcription-PCR and Western blotting. Moreover, the proliferative ability of HT29 cells introduced with Hath1 was assessed by means of colony formation assay and xenografting. Expression of Hath1, Muc2, cyclin D1 and p27 in the xenograft tumors was also detected by Western blotting. No goblet cells were to be found in colon cancer and levels of Hath1 mRNA and Hath1, Muc2 mRNA and Muc2 were significantly down-regulated. Hath1 could decrease cyclin D1, increase p27 and Muc2 in HT29 cells and inhibit their proliferation. Hath1 may be an anti-oncogene in colon carcinogenesis.

Rsf-1 is overexpressed in non-small cell lung cancers and regulates cyclinD1 expression and ERK activity

International Nuclear Information System (INIS)

Li, Qingchang; Dong, Qianze; Wang, Enhua

2012-01-01

Highlights: ► Rsf-1 expression is elevated in non-small cell lung cancers. ► Rsf-1 depletion inhibits proliferation and increased apoptosis in lung cancer cells. ► Rsf-1 depletion decreases the level of cyclinD1 and phosphor-ERK expression. -- Abstract: Rsf-1 (HBXAP) was recently reported to be overexpressed in various cancers and associated with the malignant behavior of cancer cells. However, the expression of Rsf-1 in primary lung cancer and its biological roles in non-small cell lung cancer (NSCLC) have not been reported. The molecular mechanism of Rsf-1 in cancer aggressiveness remains ambiguous. In the present study, we analyzed the expression pattern of Rsf-1 in NSCLC tissues and found that Rsf-1 was overexpressed at both the mRNA and protein levels. There was a significant association between Rsf-1 overexpression and TNM stage (p = 0.0220) and poor differentiation (p = 0.0013). Furthermore, knockdown of Rsf-1 expression in H1299 and H460 cells with high endogenous Rsf-1 expression resulted in a decrease of colony formation ability and inhibition of cell cycle progression. Rsf-1 knockdown also induced apoptosis in these cell lines. Further analysis showed that Rsf-1 knockdown decreased cyclin D1 expression and phospho-ERK levels. In conclusion, Rsf-1 is overexpressed in NSCLC and contributes to malignant cell growth by cyclin D1 and ERK modulation, which makes Rsf-1 a candidate therapeutic target in lung cancer.

Promoter de-methylation of cyclin D2 by sulforaphane in prostate cancer cells

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Hsu Anna

2011-10-01

Full Text Available Abstract Sulforaphane (SFN, an isothiocyanate derived from cruciferous vegetables, induces potent anti-proliferative effects in prostate cancer cells. One mechanism that may contribute to the anti-proliferative effects of SFN is the modulation of epigenetic marks, such as inhibition of histone deacetylase (HDAC enzymes. However, the effects of SFN on other common epigenetic marks such as DNA methylation are understudied. Promoter hyper-methylation of cyclin D2, a major regulator of cell cycle, is correlated with prostate cancer progression, and restoration of cyclin D2 expression exerts anti-proliferative effects on LnCap prostate cancer cells. Our study aimed to investigate the effects of SFN on DNA methylation status of cyclin D2 promoter, and how alteration in promoter methylation impacts cyclin D2 gene expression in LnCap cells. We found that SFN significantly decreased the expression of DNA methyltransferases (DNMTs, especially DNMT1 and DNMT3b. Furthermore, SFN significantly decreased methylation in cyclin D2 promoter regions containing c-Myc and multiple Sp1 binding sites. Reduced methlyation of cyclin D2 promoter corresponded to an increase in cyclin D2 transcript levels, suggesting that SFN may de-repress methylation-silenced cyclin D2 by impacting epigenetic pathways. Our results demonstrated the ability of SFN to epigenetically modulate cyclin D2 expression, and provide novel insights into the mechanisms by which SFN may regulate gene expression as a prostate cancer chemopreventive agent.

Speeding through cell cycle roadblocks: Nuclear cyclin D1-dependent kinase and neoplastic transformation

Directory of Open Access Journals (Sweden)

Diehl J Alan

2008-09-01

Full Text Available Abstract Mitogenic induction of cyclin D1, the allosteric regulator of CDK4/6, is a key regulatory event contributing to G1 phase progression. Following the G1/S transition, cyclin D1 activation is antagonized by GSK3β-dependent threonine-286 (Thr-286 phosphorylation, triggering nuclear export and subsequent cytoplasmic degradation mediated by the SCFFbx4-αBcrystallin E3 ubiquitin ligase. Although cyclin D1 overexpression occurs in numerous malignancies, overexpression of cyclin D1 alone is insufficient to drive transformation. In contrast, cyclin D1 mutants refractory to phosphorylation-dependent nuclear export and degradation are acutely transforming. This raises the question of whether overexpression of cyclin D1 is a significant contributor to tumorigenesis or an effect of neoplastic transformation. Significantly, recent work strongly supports a model wherein nuclear accumulation of cyclin D1-dependent kinase during S-phase is a critical event with regard to transformation. The identification of mutations within SCFFbx4-αBcrystallin ligase in primary tumors provides mechanistic insight into cyclin D1 accumulation in human cancer. Furthermore, analysis of mouse models expressing cyclin D1 mutants refractory to degradation indicate that nuclear cyclin D1/CDK4 kinase triggers DNA re-replication and genomic instability. Collectively, these new findings provide a mechanism whereby aberrations in post-translational regulation of cyclin D1 establish a cellular environment conducive to mutations that favor neoplastic growth.

Cyclin D1 and Ewing's sarcoma/PNET: A microarray analysis.

Science.gov (United States)

Fagone, Paolo; Nicoletti, Ferdinando; Salvatorelli, Lucia; Musumeci, Giuseppe; Magro, Gaetano

2015-10-01

Recent immunohistochemical analyses have showed that cyclin D1 is expressed in soft tissue Ewing's sarcoma/peripheral neuroectodermal tumor (PNET) of childhood and adolescents, while it is undetectable in both embryonal and alveolar rhabdomyosarcoma. In the present paper, microarray analysis provided evidence of a significant upregulation of cyclin D1 in Ewing's sarcoma as compared to normal tissues. In addition, we confirmed our previous findings of a significant over-expression of cyclin D1 in Ewing sarcoma as compared to rhabdomyosarcoma. Bioinformatic analysis also allowed to identify some other genes, strongly correlated to cyclin D1, which, although not previously studied in pediatric tumors, could represent novel markers for the diagnosis and prognosis of Ewing's sarcoma/PNET. The data herein provided support not only the use of cyclin D1 as a diagnostic marker of Ewing sarcoma/PNET but also the possibility of using drugs targeting cyclin D1 as potential therapeutic strategies. Copyright © 2015 Elsevier GmbH. All rights reserved.

Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes.

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Roques, Magali; Wall, Richard J; Douglass, Alexander P; Ramaprasad, Abhinay; Ferguson, David J P; Kaindama, Mbinda L; Brusini, Lorenzo; Joshi, Nimitray; Rchiad, Zineb; Brady, Declan; Guttery, David S; Wheatley, Sally P; Yamano, Hiroyuki; Holder, Anthony A; Pain, Arnab; Wickstead, Bill; Tewari, Rita

2015-11-01

Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei.

Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes

KAUST Repository

Roques, Magali; Wall, Richard J.; Douglass, Alexander P.; Ramaprasad, Abhinay; Ferguson, David J. P.; Kaindama, Mbinda L.; Brusini, Lorenzo; Joshi, Nimitray; Rchiad, ‍ Zineb; Brady, Declan; Guttery, David S.; Wheatley, Sally P.; Yamano, Hiroyuki; Holder, Anthony A.; Pain, Arnab; Wickstead, Bill; Tewari, Rita

2015-01-01

Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei.

Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes

Science.gov (United States)

Ferguson, David J. P.; Kaindama, Mbinda L.; Brusini, Lorenzo; Joshi, Nimitray; Rchiad, Zineb; Brady, Declan; Guttery, David S.; Wheatley, Sally P.; Yamano, Hiroyuki; Holder, Anthony A.; Pain, Arnab; Wickstead, Bill; Tewari, Rita

2015-01-01

Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei. PMID:26565797

Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes

KAUST Repository

Roques, Magali

2015-11-13

Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei.

Tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induces cell proliferation in normal human bronchial epithelial cells through NFκB activation and cyclin D1 up-regulation

International Nuclear Information System (INIS)

Ho, Y.-S.; Chen, Chien-Ho; Wang, Y.-J.; Pestell, Richard G.; Albanese, Chris; Chen, R.-J.; Chang, M.-C.; Jeng, J.-H.; Lin, S.-Y.; Liang, Y.-C.; Tseng, H.; Lee, W.-S.; Lin, J.-K.; Chu, J.-S.; Chen, L.-C.; Lee, C.-H.; Tso, W.-L.; Lai, Y.-C.; Wu, C.-H.

2005-01-01

Cigarette smoke contains several carcinogens known to initiate and promote tumorigenesis as well as metastasis. Nicotine is one of the major components of the cigarette smoke and the 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a tobacco-specific carcinogen. Here, we demonstrated that NNK stimulated cell proliferation in normal human bronchial epithelial cells (NHBE) and small airway epithelial cells (SAEC). Cells exposed to NNK resulted in an increase in the level of cyclin D1 protein (as early as 3-6 h). Increased phosphorylation of the Rb Ser 795 was detected at 6-15 h after NNK treatment and thereby promoted cells entering into the S phase (at 15-21 h). The increased cyclin D1 protein level was induced through activation of the transcription factor, nuclear factor kB (NFκB), in the NHBE cells. Treatment of the NHBE cells with PD98059, an ERK1/2 (extracellular signal-regulated protein kinase)-specific inhibitor, specifically suppressed the NNK-induced IκBα phosphorylation at position 32 of the serine residue, suggesting that the ERK1/2 kinase was involved in the IκBα phosphorylation induced by NFκB activation. To determine whether the NNK-induced NFκB activation and cyclin D1 induction were also observed in vivo, A/J mice were treated with NNK (9.1 mg) for 20 weeks and the results showed a significant induction of cyclin D1 and NFκB translocation determined by immunoblotting analyses. We further demonstrated that the nicotine acetylcholine receptor (nAchR), which contains the α3-subunit, was the major target mediating NNK-induced cyclin D1 expression in the NHBE cells. In summary, our findings demonstrate for the first time that NNK could stimulate normal human bronchial cell proliferation through activation of the NFκB, which in turn up-regulated the cyclin D1 expression

A Human Long Non-Coding RNA ALT1 Controls the Cell Cycle of Vascular Endothelial Cells Via ACE2 and Cyclin D1 Pathway

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Wen Li

2017-10-01

Full Text Available Background/Aims: ALT1 is a novel long non-coding RNA derived from the alternatively spliced transcript of the deleted in lymphocytic leukemia 2 (DLEU2. To date, ALT1 biological roles in human vascular endothelial cells have not been reported. Methods: ALT1 was knocked down by siRNAs. Cell proliferation was analyzed by cck-8. The existence and sequence of human ALT1 were identified by 3’ rapid amplification of cDNA ends. The interaction between lncRNA and proteins was analyzed by RNA-Protein pull down assay, RNA immunoprecipitation, and mass spectrometry analysis. Results: ALT1 was expressed in human umbilical vein endothelial cells (HUVECs. The expression of ALT1 was significantly downregulated in contact-inhibited HUVECs and in hypoxia-induced, growth-arrested HUVECs. Knocking down of ALT1 inhibited the proliferation of HUVECs by G0/G1 cell cycle arrest. We observed that angiotensin converting enzyme Ⅱ(ACE2 was a direct target gene of ALT1. Knocking-down of ALT1 or its target gene ACE2 could efficiently decrease the expression of cyclin D1 via the enhanced ubiquitination and degradation, in which HIF-1α and protein von Hippel-Lindau (pVHL might be involved. Conclusion: The results suggested the human long non-coding RNA ALT1 is a novel regulator for cell cycle of HUVECs via ACE2 and cyclin D1 pathway.

A Study to investigate the role of p27 and Cyclin E immunoexpression as a prognostic factor in early breast carcinoma

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Chetty Runjan

2011-03-01

Full Text Available Abstract Background Cyclin E and p27 expression is easy to assess in human tissues by standard immunohistochemical techniques. Immunohistochemistry is cost effective, relatively easy to perform and will play more of a role in the future management of cancer. The aim of this study was to investigate the role of p27 and cyclin E immunoexpression as a prognostic factor in early breast carcinoma. Methods Cyclin E and p27 immunohistochemistry was performed on sixty six cases of breast carcinoma submitted over a five year period to the Division of Anatomical Pathology, Groote Schuur hospital; Whittaker and Associates; and PathCare. All tumours included in this study were less than 5 cm in diameter (pT1 and pT2 stage and all the patients had wide local excisions performed. Follow up information was obtained from patient folders in the Department of Radiation Oncology. Results There was no significant association of cyclin E and p27 expression with distant metastasis free survival (MFS for all invasive carcinomas in contrast to grade, lymph node spread and vascular invasion. However, there was a statistically significant direct association of cyclin E with distant metastases in all invasive carcinomas, in the subgroup of infiltrating duct carcinomas (IDC and in the node negative group when cyclin E was stratified as negative and positive (low/high. In this study of early breast carcinoma, only 9/66 cases showed cyclin E expression. Of these, four patients had distant metastases, one patient had a local recurrence and four patients were alive at last follow-up. Furthermore, cyclin E expression was significantly associated with grade, lymph node spread, oestrogen receptor status and histological type. None of the lobular carcinomas showed cyclin E positivity and only one case of lobular carcinoma presented with distant metastases. 59/66 cases were positive (low/high for p27 while seven cases were negative, 22 cases showed low expression and 37 cases

Cyclin D1, Id1 and EMT in breast cancer

International Nuclear Information System (INIS)

Tobin, Nicholas P; Sims, Andrew H; Lundgren, Katja L; Lehn, Sophie; Landberg, Göran

2011-01-01

Cyclin D1 is a well-characterised cell cycle regulator with established oncogenic capabilities. Despite these properties, studies report contrasting links to tumour aggressiveness. It has previously been shown that silencing cyclin D1 increases the migratory capacity of MDA-MB-231 breast cancer cells with concomitant increase in 'inhibitor of differentiation 1' (ID1) gene expression. Id1 is known to be associated with more invasive features of cancer and with the epithelial-mesenchymal transition (EMT). Here, we sought to determine if the increase in cell motility following cyclin D1 silencing was mediated by Id1 and enhanced EMT-features. To further substantiate these findings we aimed to delineate the link between CCND1, ID1 and EMT, as well as clinical properties in primary breast cancer. Protein and gene expression of ID1, CCND1 and EMT markers were determined in MDA-MB-231 and ZR75 cells by western blot and qPCR. Cell migration and promoter occupancy were monitored by transwell and ChIP assays, respectively. Gene expression was analysed from publicly available datasets. The increase in cell migration following cyclin D1 silencing in MDA-MB-231 cells was abolished by Id1 siRNA treatment and we observed cyclin D1 occupancy of the Id1 promoter region. Moreover, ID1 and SNAI2 gene expression was increased following cyclin D1 knock-down, an effect reversed with Id1 siRNA treatment. Similar migratory and SNAI2 increases were noted for the ER-positive ZR75-1 cell line, but in an Id1-independent manner. In a meta-analysis of 1107 breast cancer samples, CCND1 low /ID1 high tumours displayed increased expression of EMT markers and were associated with reduced recurrence free survival. Finally, a greater percentage of CCND1 low /ID1 high tumours were found in the EMT-like 'claudin-low' subtype of breast cancer than in other subtypes. These results indicate that increased migration of MDA-MB-231 cells following cyclin D1 silencing can be mediated by Id

Mutation analysis of the negative regulator cyclin G2 in gastric cancer

African Journals Online (AJOL)

Cyclin G2 is an unconventional cyclin which might have a potential negative role in carcinogenesis. In this study, the effect of cyclin G2 overexpression on gastric cell proliferation and expression levels of cyclin G2 in normal gastric cells and gastric cancer cells were investigated. Moreover, mutation analysis was performed ...

Regulation of proliferation in developing human tooth germs by MSX homeodomain proteins and cyclin-dependent kinase inhibitor p19INK4d.

Science.gov (United States)

Kero, Darko; Vukojevic, Katarina; Stazic, Petra; Sundov, Danijela; Mardesic Brakus, Snjezana; Saraga-Babic, Mirna

2017-10-02

Before the secretion of hard dental tissues, tooth germs undergo several distinctive stages of development (dental lamina, bud, cap and bell). Every stage is characterized by specific proliferation patterns, which is regulated by various morphogens, growth factors and homeodomain proteins. The role of MSX homeodomain proteins in odontogenesis is rather complex. Expression domains of genes encoding for murine Msx1/2 during development are observed in tissues containing highly proliferative progenitor cells. Arrest of tooth development in Msx knockout mice can be attributed to impaired proliferation of progenitor cells. In Msx1 knockout mice, these progenitor cells start to differentiate prematurely as they strongly express cyclin-dependent kinase inhibitor p19 INK4d . p19 INK4d induces terminal differentiation of cells by blocking the cell cycle in mitogen-responsive G1 phase. Direct suppression of p19 INK4d by Msx1 protein is, therefore, important for maintaining proliferation of progenitor cells at levels required for the normal progression of tooth development. In this study, we examined the expression patterns of MSX1, MSX2 and p19 INK4d in human incisor tooth germs during the bud, cap and early bell stages of development. The distribution of expression domains of p19 INK4d throughout the investigated period indicates that p19 INK4d plays active role during human tooth development. Furthermore, comparison of expression domains of p19 INK4d with those of MSX1, MSX2 and proliferation markers Ki67, Cyclin A2 and pRb, indicates that MSX-mediated regulation of proliferation in human tooth germs might not be executed by the mechanism similar to one described in developing tooth germs of wild-type mouse.

Potential gene regulatory role for cyclin D3 in muscle cells

Indian Academy of Sciences (India)

Using chromatin immunoprecipitation assays, we demonstrated that expression of cyclin D3 in undifferentiated myoblasts altered histone epigenetic marks at promoters of muscle-specific genes like MyoD, Pax7, myogenin and muscle creatine kinase but not non-muscle genes. Cyclin D3 expression also reduced the mRNA ...

The effect of the ginger on the apoptosis of hippochampal cells according to the expression of BAX and Cyclin D1 genes and histological characteristics of brain in streptozotocin male diabetic rats.

Science.gov (United States)

Molahosseini, A; Taghavi, M M; Taghipour, Z; Shabanizadeh, A; Fatehi, F; Kazemi Arababadi, M; Eftekhar Vaghefe, S H

2016-10-31

Diabetes is the most common endocrine disorder in humans with multiple complications including nervous system damages. The aim of the present study was to determine the effect of ginger extract on apoptosis of the neurons of hippocampus, via evaluation of BAX and Cyclin D1 and also histological analysis, in male diabetic rats. In this experimental study, 60 Wistar rats (220 ± 30gr) were conducted in 5 groups as follow: diabetic group treated with saline (group 1), normal group treated with saline (group 2), diabetic group treated with ginger (group 3), diabetic group treated with ginger-insulin (group 4), diabetic group treated with insulin (group 5). STZ (60 mg/kg) was intraperitoneally used to induce the diabetes. Expression levels of BAX and Cyclin D1 were examined using Real-Time PCR technique and the normality of neurons was evaluated using H&E staining method. The results showed that blood glucose level significantly decreased in group 4 when compared to group 1. In molecular analysis, there was no significant difference between groups regarding the expression of BAX gens, while, the expression of Cyclin D1 were significantly decreased in group 4 compared with group 1. Histological analysis revealed that pathological symptoms were lower in group 4 than the other diabetic groups. The results of present study showed that the ginger in addition to lowering blood sugar level, changes the expression of Cyclin D1 gene and histological characteristics in a positive manner. This means that the ginger may protects neurons of the hippocampus from apoptosis in diabetic patients.

MicroRNA-16 Modulates HuR Regulation of Cyclin E1 in Breast Cancer Cells

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Xun Guo

2015-03-01

Full Text Available RNA binding protein (RBPs and microRNAs (miRNAs or miRs are post-transcriptional regulators of gene expression that are implicated in development of cancers. Although their individual roles have been studied, the crosstalk between RBPs and miRNAs is under intense investigation. Here, we show that in breast cancer cells, cyclin E1 upregulation by the RBP HuR is through specific binding to regions in the cyclin E1 mRNA 3' untranslated region (3'UTR containing U-rich elements. Similarly, miR-16 represses cyclin E1, dependent on its cognate binding sites in the cyclin E1 3'UTR. Evidence in the literature indicates that HuR can regulate miRNA expression and recruit or dissociate RNA-induced silencing complexes (RISC. Despite this, miR-16 and HuR do not affect the other’s expression level or binding to the cyclin E1 3'UTR. While HuR overexpression partially blocks miR-16 repression of a reporter mRNA containing the cyclin E1 3'UTR, it does not block miR-16 repression of endogenous cyclin E1 mRNA. In contrast, miR-16 blocks HuR-mediated upregulation of cyclin E1. Overall our results suggest that miR-16 can override HuR upregulation of cyclin E1 without affecting HuR expression or association with the cyclin E1 mRNA.

Selective induction of cyclin B protein abrogates the G2 delay after irradiation

International Nuclear Information System (INIS)

Kao, G.; Muschel, R.J.; Maity, A.; Kunig, A.; McKenna, W.G.

1996-01-01

Purpose/Objective: Irradiation of tumor cells commonly results in G2 delay, which has been postulated to allow DNA repair and cell survival. The G2 delay after irradiation is also often marked in some cell lines by delayed expression of cyclin B protein, suggesting a role for cyclin B regulation. Investigations of these hypotheses however has been hampered by the inability to selectively perturb the G2 delay in a physiologic manner. Materials and Methods: We have devised a system, with which we are able to selectively induce cyclin B protein expression in vivo at specific points in the cell cycle, by transfecting Hela cells with an expression vector under control of a dexamethasone-inducible promoter. Experiments were subsequently performed by synchronizing, releasing, irradiating, inducing, and harvesting these cells through the cell cycle. Results: Irradiation with 5 Gy led to a pronounced G2 delay, reflected by markedly slowed progression into mitosis, concomitant with reduced expression of cyclin B protein. Induction of cyclin B after radiation in these cells abrogated the G2 delay by approximately doubling the rate at which the cells re-enter mitosis. Treatment of irradiated untransfected control cells with dexamethasone, in which cyclin B is not induced, led to minimal changes. Studies of effects of cyclin B induction on cyclin B localization (using immunofluorescence), cdc2 phosphorylation and activation will also be presented. Conclusion: This system should allow further investigations into fundamental mechanisms of cell cycle regulation after irradiation and DNA damage. This also provides direct evidence for the first time that cyclin B protein regulation may play a role in the G2 delay following irradiation in Hela cells, perhaps complementing phosphorylation events

p75NTR enhances PC12 cell tumor growth by a non-receptor mechanism involving downregulation of cyclin D2

International Nuclear Information System (INIS)

Fritz, Melinda D.; Mirnics, Zeljka K.; Nylander, Karen D.; Schor, Nina F.

2006-01-01

p75NTR is a member of the tumor necrosis superfamily of proteins which is variably associated with induction of apoptosis and proliferation. Cyclin D2 is one of the mediators of cellular progression through G1 phase of the cell cycle. The present study demonstrates the inverse relationship between expression of cyclin D2 and expression of p75NTR in PC12 cells. Induction of p75NTR expression in p75NTR-negative PC12 cells results in downregulation of cyclin D2; suppression of p75NTR expression with siRNA in native PC12 cells results in upregulation of cyclin D2. The effects of p75NTR on cyclin D2 expression are mimicked in p75NTR-negative cells by transfection with the intracellular domain of p75NTR. Cyclin-D2-positive PC12 cell cultures grow more slowly than cyclin-D2-negative cultures, and induction of expression of cyclin D2 slows the culture growth rate of cyclin-D2-negative cells. Finally, subcutaneous murine xenografts of cyclin-D2-negative, p75NTR-positive PC12 cells more frequently and more rapidly produce tumors than the analogous xenografts of cyclin-D2-positive, p75NTR-negative cells. These results suggest that p75NTR suppresses cyclin D2 expression in PC12 cells by a mechanism distinct from its function as a nerve growth factor receptor and that cyclin D2 expression decreases cell culture and xenografted tumor growth

Cyclin G2 suppresses estrogen-mediated osteogenesis through inhibition of Wnt/β-catenin signaling.

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Jinlan Gao

Full Text Available Estrogen plays an important role in the maintenance of bone formation, and deficiency in the production of estrogen is directly linked to postmenopausal osteoporosis. To date, the underlying mechanisms of estrogen-mediated osteogenic differentiation are not well understood. In this study, a pluripotent mesenchymal precursor cell line C2C12 was used to induce osteogenic differentiation and subjected to detection of gene expressions or to manipulation of cyclin G2 expressions. C57BL/6 mice were used to generate bilateral ovariectomized and sham-operated mice for analysis of bone mineral density and protein expression. We identified cyclin G2, an unconventional member of cyclin, is involved in osteoblast differentiation regulated by estrogen in vivo and in vitro. In addition, the data showed that ectopic expression of cyclin G2 suppressed expression of osteoblast transcription factor Runx2 and osteogenic differentiation marker genes, as well as ALP activity and in vitro extracellular matrix mineralization. Mechanistically, Wnt/β-catenin signaling pathway is essential for cyclin G2 to inhibit osteogenic differentiation. To the best of our knowledge, the current study presents the first evidence that cyclin G2 serves as a negative regulator of both osteogenesis and Wnt/β-catenin signaling. Most importantly, the basal and 17β-estradiol-induced osteogenic differentiation was restored by overexpression of cyclin G2. These results taken together suggest that cyclin G2 may function as an endogenous suppressor of estrogen-induced osteogenic differentiation through inhibition of Wnt/β-catenin signaling.

Suberoylanilide hydroxamic acid (SAHA) inhibits EGF-induced cell transformation via reduction of cyclin D1 mRNA stability

International Nuclear Information System (INIS)

Zhang, Jingjie; Ouyang, Weiming; Li, Jingxia; Zhang, Dongyun; Yu, Yonghui; Wang, York; Li, Xuejun; Huang, Chuanshu

2012-01-01

Suberoylanilide hydroxamic acid (SAHA) inhibiting cancer cell growth has been associated with its downregulation of cyclin D1 protein expression at transcription level or translation level. Here, we have demonstrated that SAHA inhibited EGF-induced Cl41 cell transformation via the decrease of cyclin D1 mRNA stability and induction of G0/G1 growth arrest. We found that SAHA treatment resulted in the dramatic inhibition of EGF-induced cell transformation, cyclin D1 protein expression and induction of G0/G1 growth arrest. Further studies showed that SAHA downregulation of cyclin D1 was only observed with endogenous cyclin D1, but not with reconstitutionally expressed cyclin D1 in the same cells, excluding the possibility of SAHA regulating cyclin D1 at level of protein degradation. Moreover, SAHA inhibited EGF-induced cyclin d1 mRNA level, whereas it did not show any inhibitory effect on cyclin D1 promoter-driven luciferase reporter activity under the same experimental conditions, suggesting that SAHA may decrease cyclin D1 mRNA stability. This notion was supported by the results that treatment of cells with SAHA decreased the half-life of cyclin D1 mRNA from 6.95 h to 2.57 h. Consistent with downregulation of cyclin D1 mRNA stability, SAHA treatment also attenuated HuR expression, which has been well-characterized as a positive regulator of cyclin D1 mRNA stability. Thus, our study identifies a novel mechanism responsible for SAHA inhibiting cell transformation via decreasing cyclin D1 mRNA stability and induction of G0/G1 growth arrest in Cl41 cells. -- Highlights: ► SAHA inhibits cell transformation in Cl41 cells. ► SAHA suppresses Cyclin D1 protein expression. ► SAHA decreases cyclin D1 mRNA stability.

Epigenetically altered miR-193b targets cyclin D1 in prostate cancer

International Nuclear Information System (INIS)

Kaukoniemi, Kirsi M; Rauhala, Hanna E; Scaravilli, Mauro; Latonen, Leena; Annala, Matti; Vessella, Robert L; Nykter, Matti; Tammela, Teuvo L J; Visakorpi, Tapio

2015-01-01

Micro-RNAs (miRNA) are important regulators of gene expression and often differentially expressed in cancer and other diseases. We have previously shown that miR-193b is hypermethylated in prostate cancer (PC) and suppresses cell growth. It has been suggested that miR-193b targets cyclin D1 in several malignancies. Here, our aim was to determine if miR-193b targets cyclin D1 in prostate cancer. Our data show that miR-193b is commonly methylated in PC samples compared to benign prostate hyperplasia. We found reduced miR-193b expression (P < 0.05) in stage pT3 tumors compared to pT2 tumors in a cohort of prostatectomy specimens. In 22Rv1 PC cells with low endogenous miR-193b expression, the overexpression of miR-193b reduced CCND1mRNA levels and cyclin D1 protein levels. In addition, the exogenous expression of miR-193b decreased the phosphorylation level of RB, a target of the cyclin D1-CDK4/6 pathway. Moreover, according to a reporter assay, miR-193b targeted the 3’UTR of CCND1 in PC cells and the CCND1 activity was rescued by expressing CCND1 lacking its 3’UTR. Immunohistochemical analysis of cyclin D1 showed that castration-resistant prostate cancers have significantly (P = 0.0237) higher expression of cyclin D1 compared to hormone-naïve cases. Furthermore, the PC cell lines 22Rv1 and VCaP, which express low levels of miR-193b and high levels of CCND1, showed significant growth retardation when treated with a CDK4/6 inhibitor. In contrast, the inhibitor had no effect on the growth of PC-3 and DU145 cells with high miR-193b and low CCND1 expression. Taken together, our data demonstrate that miR-193b targets cyclin D1 in prostate cancer

Endoglin inhibits ERK-induced c-Myc and cyclin D1 expression to impede endothelial cell proliferation

Energy Technology Data Exchange (ETDEWEB)

Pan, Christopher C.; Bloodworth, Jeffrey C. [Division of Pharmacology, Columbus, OH 43210 (United States); Mythreye, Karthikeyan [Duke University, Department of Medicine, Durham, NC 27708 (United States); Lee, Nam Y., E-mail: lee.5064@osu.edu [Division of Pharmacology, Columbus, OH 43210 (United States); Davis Heart and Lung Research Institute, Columbus, OH 43210 (United States)

2012-08-03

Highlights: Black-Right-Pointing-Pointer Endoglin inhibits ERK activation in endothelial cells. Black-Right-Pointing-Pointer Endoglin is a regulator of c-Myc and cyclin D1 expression. Black-Right-Pointing-Pointer {beta}-arrestin2 interaction with endoglin is required for ERK/c-Myc repression. Black-Right-Pointing-Pointer Endoglin impedes cellular proliferation by targeting ERK-induced mitogenic signaling. -- Abstract: Endoglin is an endothelial-specific transforming growth factor beta (TGF-{beta}) co-receptor essential for angiogenesis and vascular remodeling. Endoglin regulates a wide range of cellular processes, including cell adhesion, migration, and proliferation, through TGF-{beta} signaling to canonical Smad and Smad-independent pathways. Despite its overall pro-angiogenic role in the vasculature, the underlying mechanism of endoglin action is poorly characterized. We previously identified {beta}-arrestin2 as a binding partner that causes endoglin internalization from the plasma membrane and inhibits ERK signaling towards endothelial migration. In the present study, we examined the mechanistic role of endoglin and {beta}-arrestin2 in endothelial cell proliferation. We show that endoglin impedes cell growth through sustained inhibition of ERK-induced c-Myc and cyclin D1 expression in a TGF-{beta}-independent manner. The down-regulation of c-Myc and cyclin D1, along with growth-inhibition, are reversed when the endoglin/{beta}-arrestin2 interaction is disrupted. Given that TGF-{beta}-induced Smad signaling potently represses c-Myc in most cell types, our findings here show a novel mechanism by which endoglin augments growth-inhibition by targeting ERK and key downstream mitogenic substrates.

Control of cyclin C levels during development of Dictyostelium.

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David M Greene

2010-05-01

Full Text Available Cdk8 and its partner cyclin C form part of the mediator complex which links the basal transcription machinery to regulatory proteins. The pair are required for correct regulation of a subset of genes and have been implicated in control of development in a number of organisms including the social amoeba Dictyostelium discoideum. When feeding, Dictyostelium amoebae are unicellular but upon starvation they aggregate to form a multicellular structure which develops into a fruiting body containing spores. Cells in which the gene encoding Cdk8 has been deleted fail to enter aggregates due to a failure of early gene expression.We have monitored the expression levels of cyclin C protein during development and find levels decrease after the multicellular mound is formed. This decrease is triggered by extracellular cAMP that, in turn, is working in part through an increase in intracellular cAMP. The loss of cyclin C is coincident with a reduction in the association of Cdk8 with a high molecular weight complex in the nucleus. Overexpression of cyclin C and Cdk8 lead to an increased rate of early development, consistent with the levels being rate limiting.Overall these results show that both cyclin C and Cdk8 are regulated during development in response to extracellular signals and the levels of these proteins are important in controlling the timing of developmental processes. These findings have important implications for the role of these proteins in controlling development, suggesting that they are targets for developmental signals to regulate gene expression.

Basaloid Squamous Cell Carcinoma of the Head and Neck: Subclassification into Basal, Ductal, and Mixed Subtypes Based on Comparison of Clinico-pathologic Features and Expression of p53, Cyclin D1, Epidermal Growth Factor Receptor, p16, and Human Papillomavirus

Directory of Open Access Journals (Sweden)

Kyung-Ja Cho

2017-07-01

Full Text Available Background Basaloid squamous cell carcinoma (BSCC is a rare variant of squamous cell carcinoma with distinct pathologic characteristics. The histogenesis of BSCC is not fully understood, and the cancer has been suggested to originate from a totipotent primitive cell in the basal cell layer of the surface epithelium or in the proximal duct of secretory glands. Methods Twenty-six cases of head and neck BSCC from Asan Medical Center, Seoul, Korea, reported during a 14-year-period were subclassified into basal, ductal, and mixed subtypes according to the expression of basal (cytokeratin [CK] 5/6, p63 or ductal markers (CK7, CK8/18. The cases were also subject to immunohistochemical study for CK19, p53, cyclin D1, epidermal growth factor receptor (EGFR, and p16 and to in situ hybridization for human papillomavirus (HPV, and the results were clinico-pathologically compared. Results Mixed subtype (12 cases was the most common, and these cases showed hypopharyngeal predilection, older age, and higher expression of CK19, p53, and EGFR than other subtypes. The basal subtype (nine cases showed frequent comedo-necrosis and high expression of cyclin D1. The ductal subtype (five cases showed the lowest expression of p53, cyclin D1, and EGFR. A small number of p16- and/or HPV-positive cases were not restricted to one subtype. BSCC was the cause of death in 19 patients, and the average follow-up period for all patients was 79.5 months. Overall survival among the three subtypes was not significantly different. Conclusions The results of this study suggest a heterogeneous pathogenesis of head and neck BSCC. Each subtype showed variable histology and immunoprofiles, although the clinical implication of heterogeneity was not determined in this study.

Expression of a TGF-{beta} regulated cyclin-dependent kinase inhibitor in normal and immortalized airway epithelial cells

Energy Technology Data Exchange (ETDEWEB)

Tierney, L.A.; Bloomfield, C.; Johnson, N.F. [and others

1995-12-01

Tumors arising from epithelial cells, including lung cancers are frequently resistant to factors that regulate growth and differentiation in normal in normal cells. Once such factor is transforming growth factor-{Beta} (TGF-{Beta}). Escape from the growth-inhibitory effects of TGF-{Beta} is thought to be a key step in the transformation of airway epithelial cells. most lung cancer cell lines require serum for growth. In contrast, normal human bronchial epithelial (NHBE) cells are exquisitely sensitive to growth-inhibitory and differentiating effects of TGF-{Beta}. The recent identification of a novel cyclin-dependent kinase inhibitor, p15{sup INK4B}, which is regulated by TGF-{Beta}, suggests a mechanism by which TGF-{Beta} mediates growth arrest in NHBE cells. The purpose of this study was two-fold: (1) to determine if p15{sup INK4B} is induced by TGF-{Beta} in NHBE cells or immortalized bronchial epithelial (R.1) cells and if that induction corresponds to a G1/S cell-cycle arrest; (2) to determine the temporal relationship between p15{sup INK4B} induction, cell-cycle arrest, and the phosphorylation state of the pRB because it is thought that p15{sup INK4B} acts indirectly by preventing phosphorylation of the RB gene product. In this study, expression of p15{sup INK4B} was examined in NHBE cells and R.1 cells at different time intervals following TGF-{Beta} treatment. The expression of this kinase inhibitor and its relationship to the cell and the pRb phosphorylation state were examined in cells that were both sensitive (NHBE) and resistant (R.1) to the effects of TGF-{Beta}. These results suggest that the cyclin-dependent kinase inhibitor, p15{sup INK4B}, is involved in airway epithelial cell differentiation and that loss or reduction of expression plays a role in the resistance of transformed or neoplastic cells to the growth-inhibitory effects of TGF-{Beta}.

Targeting cyclin B1 inhibits proliferation and sensitizes breast cancer cells to taxol

International Nuclear Information System (INIS)

Androic, Ilija; Krämer, Andrea; Yan, Ruilan; Rödel, Franz; Gätje, Regine; Kaufmann, Manfred; Strebhardt, Klaus; Yuan, Juping

2008-01-01

Cyclin B1, the regulatory subunit of cyclin-dependent kinase 1 (Cdk1), is essential for the transition from G2 phase to mitosis. Cyclin B1 is very often found to be overexpressed in primary breast and cervical cancer cells as well as in cancer cell lines. Its expression is correlated with the malignancy of gynecological cancers. In order to explore cyclin B1 as a potential target for gynecological cancer therapy, we studied the effect of small interfering RNA (siRNA) on different gynecological cancer cell lines by monitoring their proliferation rate, cell cycle profile, protein expression and activity, apoptosis induction and colony formation. Tumor formation in vivo was examined using mouse xenograft models. Downregulation of cyclin B1 inhibited proliferation of several breast and cervical cancer cell lines including MCF-7, BT-474, SK-BR-3, MDA-MB-231 and HeLa. After combining cyclin B1 siRNA with taxol, we observed an increased apoptotic rate accompanied by an enhanced antiproliferative effect in breast cancer cells. Furthermore, control HeLa cells were progressively growing, whereas the tumor growth of HeLa cells pre-treated with cyclin B1 siRNA was strongly inhibited in nude mice, indicating that cyclin B1 is indispensable for tumor growth in vivo. Our data support the notion of cyclin B1 being essential for survival and proliferation of gynecological cancer cells. Concordantly, knockdown of cyclin B1 inhibits proliferation in vitro as well as in vivo. Moreover, targeting cyclin B1 sensitizes breast cancer cells to taxol, suggesting that specific cyclin B1 targeting is an attractive strategy for the combination with conventionally used agents in gynecological cancer therapy

BAFF induces spleen CD4+ T cell proliferation by down-regulating phosphorylation of FOXO3A and activates cyclin D2 and D3 expression

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Ji, Fang; Chen, Rongjing; Liu, Baojun; Zhang, Xiaoping; Han, Junli; Wang, Haining; Shen, Gang; Tao, Jiang

2012-01-01

Highlights: ► Firstly analyze the mechanism of BAFF and anti-CD3 co-stimulation on purified mouse splenic CD4 + T cells. ► Carrying out siRNA technology to study FOXO3A protein function. ► Helpful to understand the T cell especially CD4 + T cell‘s role in immunological reaction. -- Abstract: The TNF ligand family member “B cell-activating factor belonging to the TNF family” (BAFF, also called BLyS, TALL-1, zTNF-4, and THANK) is an important survival factor for B and T cells. In this study, we show that BAFF is able to induce CD4 + spleen T cell proliferation when co-stimulated with anti-CD3. Expression of phosphorylated FOXO3A was notably down-regulated and cyclins D2 and D3 were up-regulated and higher in the CD4 + T cells when treated with BAFF and anti-CD3, as assessed by Western blotting. Furthermore, after FOXO3A was knocked down, expression of cyclin D1 was unchanged, compared with control group levels, but the expression of cyclins D2 and D3 increased, compared with the control group. In conclusion, our results suggest that BAFF induced CD4 + spleen T cell proliferation by down-regulating the phosphorylation of FOXO3A and then activating cyclin D2 and D3 expression, leading to CD4 + T cell proliferation.

Cyclin D2 in the basal process of neural progenitors is linked to non-equivalent cell fates

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Tsunekawa, Yuji; Britto, Joanne M; Takahashi, Masanori; Polleux, Franck; Tan, Seong-Seng; Osumi, Noriko

2012-01-01

Asymmetric cell division plays an indispensable role during corticogenesis for producing new neurons while maintaining a self-renewing pool of apical progenitors. The cellular and molecular determinants favouring asymmetric division are not completely understood. Here, we identify a novel mechanism for generating cellular asymmetry through the active transportation and local translation of Cyclin D2 mRNA in the basal process. This process is regulated by a unique cis-regulatory sequence found in the 3′ untranslated region (3′UTR) of the mRNA. Unequal inheritance of Cyclin D2 protein to the basally positioned daughter cell with the basal process confers renewal of the apical progenitor after asymmetric division. Conversely, depletion of Cyclin D2 in the apically positioned daughter cell results in terminal neuronal differentiation. We demonstrate that Cyclin D2 is also expressed in the developing human cortex within similar domains, thus indicating that its role as a fate determinant is ancient and conserved. PMID:22395070

Targeting cyclin B1 inhibits proliferation and sensitizes breast cancer cells to taxol

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Strebhardt Klaus

2008-12-01

Full Text Available Abstract Background Cyclin B1, the regulatory subunit of cyclin-dependent kinase 1 (Cdk1, is essential for the transition from G2 phase to mitosis. Cyclin B1 is very often found to be overexpressed in primary breast and cervical cancer cells as well as in cancer cell lines. Its expression is correlated with the malignancy of gynecological cancers. Methods In order to explore cyclin B1 as a potential target for gynecological cancer therapy, we studied the effect of small interfering RNA (siRNA on different gynecological cancer cell lines by monitoring their proliferation rate, cell cycle profile, protein expression and activity, apoptosis induction and colony formation. Tumor formation in vivo was examined using mouse xenograft models. Results Downregulation of cyclin B1 inhibited proliferation of several breast and cervical cancer cell lines including MCF-7, BT-474, SK-BR-3, MDA-MB-231 and HeLa. After combining cyclin B1 siRNA with taxol, we observed an increased apoptotic rate accompanied by an enhanced antiproliferative effect in breast cancer cells. Furthermore, control HeLa cells were progressively growing, whereas the tumor growth of HeLa cells pre-treated with cyclin B1 siRNA was strongly inhibited in nude mice, indicating that cyclin B1 is indispensable for tumor growth in vivo. Conclusion Our data support the notion of cyclin B1 being essential for survival and proliferation of gynecological cancer cells. Concordantly, knockdown of cyclin B1 inhibits proliferation in vitro as well as in vivo. Moreover, targeting cyclin B1 sensitizes breast cancer cells to taxol, suggesting that specific cyclin B1 targeting is an attractive strategy for the combination with conventionally used agents in gynecological cancer therapy.

Cyclin B1 Destruction Box-Mediated Protein Instability: The Enhanced Sensitivity of Fluorescent-Protein-Based Reporter Gene System

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Chao-Hsun Yang

2013-01-01

Full Text Available The periodic expression and destruction of several cyclins are the most important steps for the exact regulation of cell cycle. Cyclins are degraded by the ubiquitin-proteasome system during cell cycle. Besides, a short sequence near the N-terminal of cyclin B called the destruction box (D-box; CDB is also required. Fluorescent-protein-based reporter gene system is insensitive to analysis because of the overly stable fluorescent proteins. Therefore, in this study, we use human CDB fused with both enhanced green fluorescent protein (EGFP at C-terminus and red fluorescent protein (RFP, DsRed at N-terminus in the transfected human melanoma cells to examine the effects of CDB on different fluorescent proteins. Our results indicated that CDB-fused fluorescent protein can be used to examine the slight gene regulations in the reporter gene system and have the potential to be the system for screening of functional compounds in the future.

Msx homeobox genes inhibit differentiation through upregulation of cyclin D1.

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Hu, G; Lee, H; Price, S M; Shen, M M; Abate-Shen, C

2001-06-01

During development, patterning and morphogenesis of tissues are intimately coordinated through control of cellular proliferation and differentiation. We describe a mechanism by which vertebrate Msx homeobox genes inhibit cellular differentiation by regulation of the cell cycle. We show that misexpression of Msx1 via retroviral gene transfer inhibits differentiation of multiple mesenchymal and epithelial progenitor cell types in culture. This activity of Msx1 is associated with its ability to upregulate cyclin D1 expression and Cdk4 activity, while Msx1 has minimal effects on cellular proliferation. Transgenic mice that express Msx1 under the control of the mouse mammary tumor virus long terminal repeat (MMTV LTR) display impaired differentiation of the mammary epithelium during pregnancy, which is accompanied by elevated levels of cyclin D1 expression. We propose that Msx1 gene expression maintains cyclin D1 expression and prevents exit from the cell cycle, thereby inhibiting terminal differentiation of progenitor cells. Our model provides a framework for reconciling the mutant phenotypes of Msx and other homeobox genes with their functions as regulators of cellular proliferation and differentiation during embryogenesis.

Cyclin G1 inhibits the proliferation of mouse endometrial stromal cell in decidualization

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Xu Qian

2017-01-01

Full Text Available Uterine stromal cell decidualization is a dynamic physiological process in which cell proliferation, differentiation and apoptosis are orchestrated and occur in a temporal and cell-specific manner. This process is important for successful embryo implantation. Many cell-cycle regulators are involved in decidualization. The protein cyclin G1 is a unique regulator of the cell cycle with dual functions in cell proliferation. It was reported that cyclin G1 is expressed in mouse uterine stromal cells during the period of peri-implantation. To prove the function of cyclin G1 in mouse uterine stromal cells during this period, immunohistochemistry was used to stain mouse uterine tissues on days 4-8 of pregnancy. The results showed obvious spatial and temporal expression of cyclin G1 in uterine stromal cells, and that it is expressed in the cells of the primary decidual zone (PDZ on day 5 and secondary decidual zone (SDZ on days 6 and 7, when the stromal cells experienced active proliferation and differentiation was initiated. Applying the decidualization model of cultured primary stromal cells in vitro, we further revealed that the expression of cyclin G1 is associated with decidualization of stromal cells induced by medroxyprogesterone acetate (MPA and estradiol-17β (E2. RNA interference was used for the knockdown of cyclin G1 in the induced decidual cells. Flow cytometry analysis indicated that the proportion of cells in the S stage was increased, and decreased in the G2/M phase. Our study indicates that cyclin G1, as a negative regulator of the cell cycle, plays an important role in the process of decidualization in mouse uterine stromal cells by inhibiting cell-cycle progression.

Glycogen synthase kinase 3 has a limited role in cell cycle regulation of cyclin D1 levels.

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Yang, Ke; Guo, Yang; Stacey, William C; Harwalkar, Jyoti; Fretthold, Jonathan; Hitomi, Masahiro; Stacey, Dennis W

2006-08-30

The expression level of cyclin D1 plays a vital role in the control of proliferation. This protein is reported to be degraded following phosphorylation by glycogen synthase kinase 3 (GSK3) on Thr-286. We recently showed that phosphorylation of Thr-286 is responsible for a decline in cyclin D1 levels during S phase, an event required for efficient DNA synthesis. These studies were undertaken to test the possibility that phosphorylation by GSK3 is responsible for the S phase specific decline in cyclin D1 levels, and that this event is regulated by the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway which controls GSK3. We found, however, that neither PI3K, AKT, GSK3, nor proliferative signaling activity in general is responsible for the S phase decline in cyclin D1 levels. In fact, the activity of these signaling kinases does not vary through the cell cycle of proliferating cells. Moreover, we found that GSK3 activity has little influence over cyclin D1 expression levels during any cell cycle phase. Inhibition of GSK3 activity by siRNA, LiCl, or other chemical inhibitors failed to influence cyclin D1 phosphorylation on Thr-286, even though LiCl efficiently blocked phosphorylation of beta-catenin, a known substrate of GSK3. Likewise, the expression of a constitutively active GSK3 mutant protein failed to influence cyclin D1 phosphorylation or total protein expression level. Because we were unable to identify any proliferative signaling molecule or pathway which is regulated through the cell cycle, or which is able to influence cyclin D1 levels, we conclude that the suppression of cyclin D1 levels during S phase is regulated by cell cycle position rather than signaling activity. We propose that this mechanism guarantees the decline in cyclin D1 levels during each S phase; and that in so doing it reduces the likelihood that simple over expression of cyclin D1 can lead to uncontrolled cell growth.

Transforming growth factor β inhibits platelet derived growth factor-induced vascular smooth muscle cell proliferation via Akt-independent, Smad-mediated cyclin D1 downregulation.

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Abel Martin-Garrido

Full Text Available In adult tissue, vascular smooth muscle cells (VSMCs exist in a differentiated phenotype, which is defined by the expression of contractile proteins and lack of proliferation. After vascular injury, VSMC adopt a synthetic phenotype associated with proliferation, migration and matrix secretion. The transition between phenotypes is a consequence of the extracellular environment, and in particular, is regulated by agonists such as the pro-differentiating cytokine transforming growth factor β (TGFβ and the pro-proliferative cytokine platelet derived growth factor (PDGF. In this study, we investigated the interplay between TGFβ and PDGF with respect to their ability to regulate VSMC proliferation. Stimulation of human aortic VSMC with TGFβ completely blocked proliferation induced by all isoforms of PDGF, as measured by DNA synthesis and total cell number. Mechanistically, PDGF-induced Cyclin D1 mRNA and protein expression was inhibited by TGFβ. TGFβ had no effect on PDGF activation of its receptor and ERK1/2, but inhibited Akt activation. However, constitutively active Akt did not reverse the inhibitory effect of TGFβ on Cyclin D1 expression even though inhibition of the proteasome blocked the effect of TGFβ. siRNA against Smad4 completely reversed the inhibitory effect of TGFβ on PDGF-induced Cyclin D1 expression and restored proliferation in response to PDGF. Moreover, siRNA against KLF5 prevented Cyclin D1 upregulation by PDGF and overexpression of KLF5 partially reversed TGFβ-induced inhibition of Cyclin D1 expression. Taken together, our results demonstrate that KLF5 is required for PDGF-induced Cyclin D1 expression, which is inhibited by TGFβ via a Smad dependent mechanism, resulting in arrest of VSMCs in the G1 phase of the cell cycle.

Transforming growth factor β inhibits platelet derived growth factor-induced vascular smooth muscle cell proliferation via Akt-independent, Smad-mediated cyclin D1 downregulation.

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Martin-Garrido, Abel; Williams, Holly C; Lee, Minyoung; Seidel-Rogol, Bonnie; Ci, Xinpei; Dong, Jin-Tang; Lassègue, Bernard; Martín, Alejandra San; Griendling, Kathy K

2013-01-01

In adult tissue, vascular smooth muscle cells (VSMCs) exist in a differentiated phenotype, which is defined by the expression of contractile proteins and lack of proliferation. After vascular injury, VSMC adopt a synthetic phenotype associated with proliferation, migration and matrix secretion. The transition between phenotypes is a consequence of the extracellular environment, and in particular, is regulated by agonists such as the pro-differentiating cytokine transforming growth factor β (TGFβ) and the pro-proliferative cytokine platelet derived growth factor (PDGF). In this study, we investigated the interplay between TGFβ and PDGF with respect to their ability to regulate VSMC proliferation. Stimulation of human aortic VSMC with TGFβ completely blocked proliferation induced by all isoforms of PDGF, as measured by DNA synthesis and total cell number. Mechanistically, PDGF-induced Cyclin D1 mRNA and protein expression was inhibited by TGFβ. TGFβ had no effect on PDGF activation of its receptor and ERK1/2, but inhibited Akt activation. However, constitutively active Akt did not reverse the inhibitory effect of TGFβ on Cyclin D1 expression even though inhibition of the proteasome blocked the effect of TGFβ. siRNA against Smad4 completely reversed the inhibitory effect of TGFβ on PDGF-induced Cyclin D1 expression and restored proliferation in response to PDGF. Moreover, siRNA against KLF5 prevented Cyclin D1 upregulation by PDGF and overexpression of KLF5 partially reversed TGFβ-induced inhibition of Cyclin D1 expression. Taken together, our results demonstrate that KLF5 is required for PDGF-induced Cyclin D1 expression, which is inhibited by TGFβ via a Smad dependent mechanism, resulting in arrest of VSMCs in the G1 phase of the cell cycle.

Cyclin D1 in ASM Cells from Asthmatics Is Insensitive to Corticosteroid Inhibition.

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Allen, Jodi C; Seidel, Petra; Schlosser, Tobias; Ramsay, Emma E; Ge, Qi; Ammit, Alaina J

2012-01-01

Hyperplasia of airway smooth muscle (ASM) is a feature of the remodelled airway in asthmatics. We examined the antiproliferative effectiveness of the corticosteroid dexamethasone on expression of the key regulator of G(1) cell cycle progression-cyclin D1-in ASM cells from nonasthmatics and asthmatics stimulated with the mitogen platelet-derived growth factor BB. While cyclin D1 mRNA and protein expression were repressed in cells from nonasthmatics in contrast, cyclin D1 expression in asthmatics was resistant to inhibition by dexamethasone. This was independent of a repressive effect on glucocorticoid receptor translocation. Our results corroborate evidence demonstrating that corticosteroids inhibit mitogen-induced proliferation only in ASM cells from subjects without asthma and suggest that there are corticosteroid-insensitive proliferative pathways in asthmatics.

Increased expression of cyclin B1 mRNA coincides with diminished G2-phase arrest in irradiated HeLa cells treated with staurosporine or caffeine

International Nuclear Information System (INIS)

Bernhard, E.J.; Maity, A.; McKenna, W.G.; Muschel, R.J.

1994-01-01

The irradiation of cells results in delayed progression through the G 2 phase of the cell cycle. Treatment of irradiated HeLa cells with caffeine greatly reduces the G 2 -phase delay, while caffeine does not alter progression of cells through the cell cycle in unirradiated cells. In this report we demonstrate that treatment of HeLa cells with the kinase inhibitor staurosporine, but not with the inhibitor H7, also results in a reduction of the G 2 -phase arrest after irradiation. Cell cycle progression in unirradiated cells is unaffected by 4.4 nM (2ng/ml) staurosporine, which releases the radiation-induced G 2 -phase arrest. In HeLa cells, the G 2 -phase delay after irradiation in S phase is accompanied by decreased expression of cyclin B1 mRNA. Coincident with the reduction in G 2 -phase delay, we observed an increase in cyclin B1 mRNA accumulation in irradiated, staurosporine-treated cells compared to cells treated with irradiation alone. Caffeine treatment of irradiated HeLa cells also resulted in an elevation in the levels of cyclin B1 message. These results support the hypothesis that diminished cyclin B1 mRNA levels influence G 2 -phase arrest to some degree. The findings that both staurosporine and caffeine treatments reverse the depression in cyclin B1 expression suggest that these two compounds may act on a common pathway of cell cycle control in response to radiation injury. 33 refs., 6 figs

Implications of caspase-dependent proteolytic cleavage of cyclin A1 in DNA damage-induced cell death

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Woo, Sang Hyeok; Seo, Sung-Keum [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, 215-4 Gongneung-dong, Nowon-gu, Seoul (Korea, Republic of); An, Sungkwan; Choe, Tae-Boo [Department of Microbiological Engineering, Kon-Kuk University, Gwangjin-gu, Seoul (Korea, Republic of); Hong, Seok-Il [Department of Laboratory Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, 215-4 Gongneung-dong, Nowon-gu, Seoul (Korea, Republic of); Lee, Yun-Han, E-mail: yhlee87@yuhs.ac [Department of Radiation Oncology, College of Medicine, Yonsei University, 250 Seongsan-no, Seodaemun-gu, Seoul (Korea, Republic of); Park, In-Chul, E-mail: parkic@kcch.re.kr [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, 215-4 Gongneung-dong, Nowon-gu, Seoul (Korea, Republic of)

2014-10-24

Highlights: • Caspase-1 mediates doxorubicin-induced downregulation of cyclin A1. • Active caspase-1 effectively cleaved cyclin A1 at D165. • Cyclin A1 expression is involved in DNA damage-induced cell death. - Abstract: Cyclin A1 is an A-type cyclin that directly binds to CDK2 to regulate cell-cycle progression. In the present study, we found that doxorubicin decreased the expression of cyclin A1 at the protein level in A549 lung cancer cells, while markedly downregulating its mRNA levels. Interestingly, doxorubicin upregulated caspase-1 in a concentration-dependent manner, and z-YAVD-fmk, a specific inhibitor of caspase-1, reversed the doxorubicin-induced decrease in cyclin A1 in A549 lung cancer and MCF7 breast cancer cells. Active caspase-1 effectively cleaved cyclin A1 at D165 into two fragments, which in vitro cleavage assays showed were further cleaved by caspase-3. Finally, we found that overexpression of cyclin A1 significantly reduced the cytotoxicity of doxorubicin, and knockdown of cyclin A1 by RNA interference enhanced the sensitivity of cells to ionizing radiation. Our data suggest a new mechanism for the downregulation of cyclin A1 by DNA-damaging stimuli that could be intimately involved in the cell death induced by DNA damage-inducing stimuli, including doxorubicin and ionizing radiation.

Cyclin D1 represses p300 transactivation through a cyclin-dependent kinase-independent mechanism.

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Fu, Maofu; Wang, Chenguang; Rao, Mahadev; Wu, Xiaofang; Bouras, Toula; Zhang, Xueping; Li, Zhiping; Jiao, Xuanmao; Yang, Jianguo; Li, Anping; Perkins, Neil D; Thimmapaya, Bayar; Kung, Andrew L; Munoz, Alberto; Giordano, Antonio; Lisanti, Michael P; Pestell, Richard G

2005-08-19

Cyclin D1 encodes a regulatory subunit, which with its cyclin-dependent kinase (Cdk)-binding partner forms a holoenzyme that phosphorylates and inactivates the retinoblastoma protein. In addition to its Cdk binding-dependent functions, cyclin D1 regulates cellular differentiation in part by modifying several transcription factors and nuclear receptors. The molecular mechanism through which cyclin D1 regulates the function of transcription factors involved in cellular differentiation remains to be clarified. The histone acetyltransferase protein p300 is a co-integrator required for regulation of multiple transcription factors. Here we show that cyclin D1 physically interacts with p300 and represses p300 transactivation. We demonstrated further that the interaction of the two proteins occurs at the peroxisome proliferator-activated receptor gamma-responsive element of the lipoprotein lipase promoter in the context of the local chromatin structure. We have mapped the domains in p300 and cyclin D1 involved in this interaction. The bromo domain and cysteine- and histidine-rich domains of p300 were required for repression by cyclin D1. Cyclin D1 repression of p300 was independent of the Cdk- and retinoblastoma protein-binding domains of cyclin D1. Cyclin D1 inhibits histone acetyltransferase activity of p300 in vitro. Microarray analysis identified a signature of genes repressed by cyclin D1 and induced by p300 that promotes cellular differentiation and induces cell cycle arrest. Together, our results suggest that cyclin D1 plays an important role in cellular proliferation and differentiation through regulation of p300.

VHL-mediated hypoxia regulation of cyclin D1 in renal carcinoma cells.

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Bindra, Ranjit S; Vasselli, James R; Stearman, Robert; Linehan, W Marston; Klausner, Richard D

2002-06-01

Renal cell carcinoma is associated with mutation of the von Hippel-Lindau (VHL) tumor suppressor gene. Cell lines derived from these tumors cannot exit the cell cycle when deprived of growth factors, and the ability to exit the cell cycle can be restored by the reintroduction of wild-type protein VHL (pVHL). Here, we report that cyclin D1 is overexpressed and remains inappropriately high in during contact inhibition in pVHL-deficient cell lines. In addition, hypoxia increased the expression of cyclin D1 specifically in pVHL-negative cell lines into which pVHL expression was restored. Hypoxic-induction of cyclin D1 was not observed in other pVHL-positive cell lines. This suggests a model whereby in some kidney cell types, pVHL may regulate a proliferative response to hypoxia, whereas the loss of pVHL leads to constitutively elevated cyclin D1 and abnormal proliferation under normal growth conditions.

BAFF induces spleen CD4{sup +} T cell proliferation by down-regulating phosphorylation of FOXO3A and activates cyclin D2 and D3 expression

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Ji, Fang; Chen, Rongjing [Department of Orthodontics, Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai (China); Liu, Baojun [Laboratory of Lung, Inflammation and Cancers, Huashan Hospital, Fudan University, Shanghai (China); Zhang, Xiaoping [Department of Nuclear Medicine, Shanghai 10th People' s Hospital, Tongji University School of Medicine, Shanghai 200072 (China); Han, Junli; Wang, Haining [Department of General Dentistry, Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai (China); Shen, Gang [Department of Orthodontics, Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai (China); Tao, Jiang, E-mail: taojiang2012@yahoo.cn [Department of General Dentistry, Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai (China)

2012-09-07

Highlights: Black-Right-Pointing-Pointer Firstly analyze the mechanism of BAFF and anti-CD3 co-stimulation on purified mouse splenic CD4{sup +} T cells. Black-Right-Pointing-Pointer Carrying out siRNA technology to study FOXO3A protein function. Black-Right-Pointing-Pointer Helpful to understand the T cell especially CD4{sup +} T cell's role in immunological reaction. -- Abstract: The TNF ligand family member 'B cell-activating factor belonging to the TNF family' (BAFF, also called BLyS, TALL-1, zTNF-4, and THANK) is an important survival factor for B and T cells. In this study, we show that BAFF is able to induce CD4{sup +} spleen T cell proliferation when co-stimulated with anti-CD3. Expression of phosphorylated FOXO3A was notably down-regulated and cyclins D2 and D3 were up-regulated and higher in the CD4{sup +} T cells when treated with BAFF and anti-CD3, as assessed by Western blotting. Furthermore, after FOXO3A was knocked down, expression of cyclin D1 was unchanged, compared with control group levels, but the expression of cyclins D2 and D3 increased, compared with the control group. In conclusion, our results suggest that BAFF induced CD4{sup +} spleen T cell proliferation by down-regulating the phosphorylation of FOXO3A and then activating cyclin D2 and D3 expression, leading to CD4{sup +} T cell proliferation.

The cyclin-dependent kinase inhibitor flavopiridol disrupts sodium butyrate-induced p21WAF1/CIP1 expression and maturation while reciprocally potentiating apoptosis in human leukemia cells.

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Rosato, Roberto R; Almenara, Jorge A; Cartee, Leanne; Betts, Vicki; Chellappan, Srikumar P; Grant, Steven

2002-02-01

Interactions between the cyclin-dependent kinase inhibitor flavopiridol (FP) and the histone deacetylase inhibitor sodium butyrate (SB) have been examined in human leukemia cells (U937) in relation to differentiation and apoptosis. Whereas 1 mM of SB or 100 nM of FP minimally induced apoptosis (4% and 10%, respectively) at 24 h, simultaneous exposure of U937 cells to these agents dramatically increased cell death (e.g., approximately 60%), reflected by both morphological and Annexin/propidium iodide-staining features, procaspase 3 activation, and poly(ADP-ribose) polymerase cleavage. Similar interactions were observed in human promyelocytic (HL-60), B-lymphoblastic (Raji), and T-lymphoblastic (Jurkat) leukemia cells. Coadministration of FP opposed SB-mediated accumulation of cells in G0G1 and differentiation, reflected by reduced CD11b expression, but instead dramatically increased procaspase-3, procaspase-8, Bid, and poly(ADP-ribose) polymerase cleavage, as well as mitochondrial damage (e.g., loss of mitochondrial membrane potential and cytochrome c release). FP also blocked SB-related p21WAF1-CIP1 induction through a caspase-independent mechanism and triggered the caspase-mediated cleavage of p27KIP1 and retinoblastoma protein. The latter event was accompanied by a marked reduction in retinoblastoma protein/E2F1 complex formation. However, FP did not modify the extent of SB-associated acetylation of histones H3 and H4. Treatment of cells with FP/SB also resulted in the caspase-mediated cleavage of Bcl-2 and caspase-independent down-regulation of Mcl-1. Levels of cyclins A, D1, and E, and X-linked inhibitor of apoptosis also declined in SB/FP-treated cells. Finally, FP/SB coexposure potently induced apoptosis in two primary acute myelogenous leukemia samples. Together, these findings demonstrate that FP, when combined with SB, induces multiple perturbations in cell cycle and apoptosis regulatory proteins, which oppose leukemic cell differentiation but instead

Differential expression of cyclin D1 in keratin-producing odontogenic cysts.

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Vera-Sirera, Beatriz; Forner-Navarro, Leopoldo; Vera-Sempere, Francisco

2015-01-01

The aim of the present study was to analyze the expression levels of Cyclin D1 (CCD1), a nuclear protein that plays a crucial role in cell cycle progression, in a series of keratin-producing odontogenic cysts. A total of 58 keratin-producing odontogenic cysts, diagnosed over ten years and classified according to the WHO 2005 criteria, were immunohistochemically analyzed in terms of CCD1 expression, which was quantified in the basal, suprabasal and intermediate/superficial epithelial compartments. The extent of immunostaining was measured as a proportion of total epithelial thickness. Quantified immunohistochemical data were correlated with clinicopathological features and clinical recurrence. Keratin-producing odontogenic cysts were classified as 6 syndromic keratocystic odontogenic tumors (S-KCOT), 40 sporadic or non-syndromic KCOT (NS-KCOT) and 12 orthokeratinized odontogenic cysts (OOC). Immunohistochemically, CCD1 staining was evident predominantly in the parabasal region of all cystic lesions, but among-lesion differences were apparent, showing a clear expansion of parabasal compartment especially in the S-KCOT, followed to a lesser extent in the NS-KCOT, and being much more reduced in the OOC, which had the greatest average epithelial thickness. The differential expression of CCD1 noted in the present study suggests that dysregulation of cell cycle progression from G1 to the S phase contributes to the different aggressiveness of these lesions. However, CCD1 expression levels did not predict NS-KCOT recurrence, which is likely influenced by factors unrelated to lesion biology.

Clinicopathological significance of p16, cyclin D1, Rb and MIB-1 levels in skull base chordoma and chondrosarcoma

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Jun-qi Liu

2015-09-01

Full Text Available Objective: To investigate the expression of p16, cyclin D1, retinoblastoma tumor suppressor protein (Rb and MIB-1 in skull base chordoma and chondrosarcoma tissues, and to determine the clinicopathological significance of the above indexes in these diseases. Methods: A total of 100 skull base chordoma, 30 chondrosarcoma, and 20 normal cartilage tissue samples were analyzed by immunohistochemistry. The expression levels of p16, cyclinD1, Rb and MIB-1 proteins were assessed for potential correlation with the clinicopathological features. Results: As compared to normal cartilage specimen (control, there was decreased expression of p16, and increased expression of cyclin D1, Rb and MIB-1 proteins, in both skull base chordoma and chondrosarcoma specimens. MIB-1 LI levels were significantly increased in skull base chordoma specimens with negative expression of p16, and positive expression of cyclin D1 and Rb (P  0.05. However, p16 and MIB-1 levels correlated with the intradural invasion, and expression of p16, Rb and MIB-1 correlated with the number of tumor foci (P < 0.05. Further, the expression of p16 and MIB-1 appeared to correlate with the prognosis of patients with skull base chordoma. Conclusions: The abnormal expression of p16, cyclin D1 and Rb proteins might be associated with the tumorigenesis of skull base chordoma and chondrosarcoma. Keywords: p16, Cyclin D1, Rb, MIB-1, Skull base chordoma, Skull base chondrosarcoma

Change in expression of cyclin G2 in kidney cancer cell and its significance.

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Cui, D W; Sun, G G; Cheng, Y J

2014-04-01

This study aims to analyze the expression and clinical significance of cyclin G2 (CCNG2) in kidney carcinoma, and the biological effect in its cell line by CCNG2 overexpression. Immunohistochemistry and western blot were used to analyze CCNG2 protein expression in 63 cases of kidney cancer and normal tissues to study the relationship between CCNG2 expression and clinical factors. CCNG2 lentiviral vector and empty vector were respectively transfected into kidney ACHN cell line. During immunohistochemistry, the level of CCNG2 protein expression was found to be significantly lower in kidney cancer tissue than normal tissues (P kidney cancer tissue was respectively found to be significantly lower than in normal tissues (P 0.05), but it was correlated with lymph node metastasis, clinic stage, and histological grade (P kidney cancer and correlated significantly with lymph node metastasis, clinical stage, histological grade, and poor overall survival, suggesting that CCNG2 may play important roles as a negative regulator to kidney cancer ACHN cell by promoting degradation of CDK2.

Cyclin D1 and mammary carcinoma: new insights from transgenic mouse models

International Nuclear Information System (INIS)

Sutherland, Robert L; Musgrove, Elizabeth A

2002-01-01

Cyclin D1 is one of the most commonly overexpressed oncogenes in breast cancer, with 45–50% of primary ductal carcinomas overexpressing this oncoprotein. Targeted deletion of the gene encoding cyclin D1 demonstrates an essential role in normal mammary gland development while transgenic studies provide evidence that cyclin D1 is a weak oncogene in mammary epithelium. In a recent exciting development, Yu et al. demonstrate that cyclin D1-deficient mice are resistant to mammary carcinomas induced by c-neu and v-Ha-ras, but not those induced by c-myc or Wnt-1. These findings define a pivotal role for cyclin D1 in a subset of mammary cancers in mice and imply a functional role for cyclin D1 overexpression in human breast cancer

Cyclin D-Cdk4 is regulated by GATA-1 and required for megakaryocyte growth and polyploidization.

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Muntean, Andrew G; Pang, Liyan; Poncz, Mortimer; Dowdy, Steven F; Blobel, Gerd A; Crispino, John D

2007-06-15

Endomitosis is a unique form of cell cycle used by megakaryocytes, in which the latter stages of mitosis are bypassed so that the cell can increase its DNA content and size. Although several transcription factors, including GATA-1 and RUNX-1, have been implicated in this process, the link between transcription factors and polyploidization remains undefined. Here we show that GATA-1-deficient megakaryocytes, which display reduced size and polyploidization, express nearly 10-fold less cyclin D1 and 10-fold increased levels of p16 compared with their wild-type counterparts. We further demonstrate that cyclin D1 is a direct GATA-1 target in megakaryocytes, but not erythroid cells. Restoration of cyclin D1 expression, when accompanied by ectopic overexpression of its partner Cdk4, resulted in a dramatic increase in megakaryocyte size and DNA content. However, terminal differentiation was not rescued. Of note, polyploidization was only modestly reduced in cyclin D1-deficient mice, likely due to compensation by elevated cyclin D3 expression. Finally, consistent with an additional defect conferred by increased levels of p16, inhibition of cyclin D-Cdk4 complexes with a TAT-p16 fusion peptide significantly blocked polyploidization of wild-type megakaryocytes. Together, these data show that GATA-1 controls growth and polyploidization by regulating cyclin D-Cdk4 kinase activity.

Cyclin D–Cdk4 is regulated by GATA-1 and required for megakaryocyte growth and polyploidization

Science.gov (United States)

Muntean, Andrew G.; Pang, Liyan; Poncz, Mortimer; Dowdy, Steven F.; Blobel, Gerd A.

2007-01-01

Endomitosis is a unique form of cell cycle used by megakaryocytes, in which the latter stages of mitosis are bypassed so that the cell can increase its DNA content and size. Although several transcription factors, including GATA-1 and RUNX-1, have been implicated in this process, the link between transcription factors and polyploidization remains undefined. Here we show that GATA-1–deficient megakaryocytes, which display reduced size and polyploidization, express nearly 10-fold less cyclin D1 and 10-fold increased levels of p16 compared with their wild-type counterparts. We further demonstrate that cyclin D1 is a direct GATA-1 target in megakaryocytes, but not erythroid cells. Restoration of cyclin D1 expression, when accompanied by ectopic overexpression of its partner Cdk4, resulted in a dramatic increase in megakaryocyte size and DNA content. However, terminal differentiation was not rescued. Of note, polyploidization was only modestly reduced in cyclin D1–deficient mice, likely due to compensation by elevated cyclin D3 expression. Finally, consistent with an additional defect conferred by increased levels of p16, inhibition of cyclin D-Cdk4 complexes with a TAT-p16 fusion peptide significantly blocked polyploidization of wild-type megakaryocytes. Together, these data show that GATA-1 controls growth and polyploidization by regulating cyclin D-Cdk4 kinase activity. PMID:17317855

Peroxisome proliferator-activated receptor α (PPARα mRNA expression in human hepatocellular carcinoma tissue and non-cancerous liver tissue

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Kurokawa Tsuyoshi

2011-12-01

Full Text Available Abstract Background Peroxisome proliferator-activated receptor α (PPARα regulates lipid metabolism in the liver. It is unclear, however, how this receptor changes in liver cancer tissue. On the other hand, mouse carcinogenicity studies showed that PPARα is necessary for the development of liver cancer induced by peroxisome proliferators, and the relationship between PPARα and the development of liver cancer have been the focus of considerable attention. There have been no reports, however, demonstrating that PPARα is involved in the development of human liver cancer. Methods The subjects were 10 patients who underwent hepatectomy for hepatocellular carcinoma. We assessed the expression of PPARα mRNA in human hepatocellular carcinoma tissue and non-cancerous tissue, as well as the expression of target genes of PPARα, carnitine palmitoyltransferase 1A and cyclin D1 mRNAs. We also evaluated glyceraldehyde 3-phosphate dehydrogenase, a key enzyme in the glycolytic system. Results The amounts of PPARα, carnitine palmitoyltransferase 1A and glyceraldehyde 3-phosphate dehydrogenase mRNA in cancerous sections were significantly increased compared to those in non-cancerous sections. The level of cyclin D1 mRNA tends to be higher in cancerous than non-cancerous sections. Although there was a significant correlation between the levels of PPARα mRNA and cyclin D1 mRNA in both sections, however the correlation was higher in cancerous sections. Conclusion The present investigation indicated increased expression of PPARα mRNA and mRNAs for PPARα target genes in human hepatocellular carcinoma. These results might be associated with its carcinogenesis and characteristic features of energy production.

Immunohistochemical comparison of cyclin D1 and P16 in odontogenic keratocyst and unicystic ameloblastoma

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Seyed Mohammad Razavi

2013-01-01

Conclusion: Cyclin D1 did show a higher staining intensity in UAs compared to the keratocysts, although the expression of P16 was similar in the studied groups. The invasive growth of OKC might be related to the state of expression of cyclin D1 and P16 in the epithelium of this cyst.

Cyc17, a meiosis-specific cyclin, is essential for anaphase initiation and chromosome segregation in Tetrahymena thermophila.

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Yan, Guan-Xiong; Dang, Huai; Tian, Miao; Zhang, Jing; Shodhan, Anura; Ning, Ying-Zhi; Xiong, Jie; Miao, Wei

2016-07-17

Although the role of cyclins in controlling nuclear division is well established, their function in ciliate meiosis remains unknown. In ciliates, the cyclin family has undergone massive expansion which suggests that diverse cell cycle systems exist, and this warrants further investigation. A screen for cyclins in the model ciliate Tetrahymena thermophila showed that there are 34 cyclins in this organism. Only 1 cyclin, Cyc17, contains the complete cyclin core and is specifically expressed during meiosis. Deletion of CYC17 led to meiotic arrest at the diakinesis-like metaphase I stage. Expression of genes involved in DNA metabolism and chromosome organization (chromatin remodeling and basic chromosomal structure) was repressed in cyc17 knockout matings. Further investigation suggested that Cyc17 is involved in regulating spindle pole attachment, and is thus essential for chromosome segregation at meiosis. These findings suggest a simple model in which chromosome segregation is influenced by Cyc17.

Cytoplasmic sequestration of cyclin D1 associated with cell cycle withdrawal of neuroblastoma cells

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Sumrejkanchanakij, Piyamas; Eto, Kazuhiro; Ikeda, Masa-Aki

2006-01-01

The regulation of D-type cyclin-dependent kinase activity is critical for neuronal differentiation and apoptosis. We recently showed that cyclin D1 is sequestered in the cytoplasm and that its nuclear localization induces apoptosis in postmitotic primary neurons. Here, we further investigated the role of the subcellular localization of cyclin D1 in cell cycle withdrawal during the differentiation of N1E-115 neuroblastoma cells. We show that cyclin D1 became predominantly cytoplasmic after differentiation. Targeting cyclin D1 expression to the nucleus induced phosphorylation of Rb and cdk2 kinase activity. Furthermore, cyclin D1 nuclear localization promoted differentiated N1E-115 cells to reenter the cell cycle, a process that was inhibited by p16 INK4a , a specific inhibitor of D-type cyclin activity. These results indicate that cytoplasmic sequestration of cyclin D1 plays a role in neuronal cell cycle withdrawal, and suggests that the abrogation of machinery involved in monitoring aberrant nuclear cyclin D1 activity contributes to neuronal tumorigenesis

The inhibition of LPS-induced splenocyte proliferation by ortho-substituted and microbially dechlorinated polychlorinated biphenyls is associated with a decreased expression of cyclin D2

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Smithwick, L. Ashley; Quensen, John F.; Smith, Andrew; Kurtz, David T.; London, Lucille; Morris, Pamela J.

2004-01-01

Immunological effects of polychlorinated biphenyls (PCBs) have been demonstrated in our laboratories with the preferential inhibition of lipopolysaccharide (LPS)-induced splenocyte proliferation by ortho-substituted PCB congeners. An investigation of the mechanism behind this immunotoxicity revealed an interruption in the progression of murine lymphocytes from G 0 /G 1 into S phase by Aroclor 1242 and the di-ortho-substituted congener, 2,2'-chlorobiphenyl (CB), whereas, a non-ortho-substituted congener, 4,4'-CB, did not affect cell cycle progression. This interruption of cell cycle progression by 2,2'-CB and Aroclor 1242 was associated with a decreased expression of the cell cycle regulatory protein, cyclin D2, while expression was not affected by exposure to the non-ortho-substituted 4,4'-CB. These results suggest the preferential inhibition of LPS-induced splenocyte proliferation by ortho-substituted congeners is a result of a decreased expression of cyclin D2, which leads to an interruption in cell cycle progression. In addition, PCB mixtures with an increased percentage of chlorines in the ortho position following an environmentally occurring degradation process inhibited LPS-induced proliferation, interrupted cell cycle progression, and decreased cyclin D2 expression. This study provides evidence for a mechanism of action of the immunological effects of ortho-substituted individual congeners as well as environmentally relevant mixtures enriched in congeners with this substitution pattern

The expression of cyclin-dependent kinase inhibitors p15, p16, p21, and p27 during ovarian follicle growth initiation in the mouse

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Bayrak Aykut

2003-05-01

Full Text Available Abstract Background Cyclins regulate the cell cycle in association with cyclin dependent kinases (CDKs. CDKs are under inhibitory control of cyclin dependent kinase inhibitors (CDKIs. Method In this study we tested the expression of CDKIs p15, p16, p21 and p27 by immunohistochemistry to determine the role of CDKIs in the initiation of primordial follicle growth. Ovaries were collected from 60-day-old cycling B6D2F1/J mice (n = 16. Results Expression of p15, p16, p21 and p27 did not vary in granulosa and theca cells by the follicle stage. However, p16 staining was stronger (++ in the oocytes of all primordial, and 57.4 ± 3.1% of primary follicles compared to the remaining primary and more advanced follicles (+. Interestingly, primary follicles with weaker (+ oocyte staining for p16 had significantly larger mean follicle diameter compared to the primary and primordial follicles with stronger (++ oocyte staining (55.6 ± 2.1 vs. 32.0 ± 1.0 and 26.5 ± 0.7 μm, respectively, p Conclusions These preliminary findings suggest that the initiation of oocyte growth, which seems to lead follicle growth, is associated with diminished p16 expression in the mouse ovary. Further studies are needed to investigate the factors that regulate the expression of p16 in the oocyte, which might also govern the initiation of primordial follicle growth.

The coffee diterpene kahweol suppresses the cell proliferation by inducing cyclin D1 proteasomal degradation via ERK1/2, JNK and GKS3β-dependent threonine-286 phosphorylation in human colorectal cancer cells.

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Park, Gwang Hun; Song, Hun Min; Jeong, Jin Boo

2016-09-01

Kahweol as a coffee-specific diterpene has been reported to exert anti-cancer properties. However, the mechanism responsible for the anti-cancer effects of kahweol is not fully understood. The main aim of this investigation was to determine the effect of kahweol on cell proliferation and the possible mechanisms in human colorectal cancer cells. Kahweol inhibited markedly the proliferation of human colorectal cancer cell lines such as HCT116, SW480. Kahweol decreased cyclin D1 protein level in HCT116 and SW480 cells. Contrast to protein levels, cyclin D1 mRNA level and promoter activity did not be changed by kahweol treatment. MG132 treatment attenuated kahweol-mediated cyclin D1 downregulation and the half-life of cyclin D1 was decreased in kahweol-treated cells. Kahweol increased phosphorylation of cyclin D1 at threonine-286 and a point mutation of threonine-286 to alanine attenuated cyclin D1 degradation by kahweol. Inhibition of ERK1/2 by PD98059, JNK by SP600125 or GSK3β by LiCl suppressed cyclin D1 phosphorylation and downregulation by kahweol. Furthermore, the inhibition of nuclear export by LMB attenuated cyclin D1 degradation by kahweol. In conclusion, kahweol-mediated cyclin D1 degradation may contribute to the inhibition of the proliferation in human colorectal cancer cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

Targeting the AKT/GSK3β/Cyclin D1/Cdk4 Survival Signaling Pathway for Eradication of Tumor Radioresistance Acquired by Fractionated Radiotherapy

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Shimura, Tsutomu; Kakuda, Satoshi; Ochiai, Yasushi; Kuwahara, Yoshikazu; Takai, Yoshihiro; Fukumoto, Manabu

2011-01-01

Purpose: Radioresistance is a major cause of treatment failure of radiotherapy (RT) in human cancer. We have recently revealed that acquired radioresistance of tumor cells induced by fractionated radiation is attributable to cyclin D1 overexpression as a consequence of the downregulation of GSK3β-dependent cyclin D1 proteolysis mediated by a constitutively activated serine-threonine kinase, AKT. This prompted us to hypothesize that targeting the AKT/GSK3β/cyclin D1 pathway may improve fractionated RT by suppressing acquired radioresistance of tumor cells. Methods and Materials: Two human tumor cell lines with acquired radioresistance were exposed to X-rays after incubation with either an AKT inhibitor, AKT/PKB signaling inhibitor-2 (API-2), or a Cdk4 inhibitor (Cdk4-I). Cells were then subjected to immunoblotting, clonogenic survival assay, cell growth analysis, and cell death analysis with TUNEL and annexin V staining. In vivo radiosensitivity was assessed by growth of human tumors xenografted into nude mice. Results: Treatment with API-2 resulted in downregulation of cyclin D1 expression in cells with acquired radioresistance. Cellular radioresistance disappeared completely both in vitro and in vivo with accompanying apoptosis when treated with API-2. Furthermore, inhibition of cyclin D1/Cdk4 by Cdk4-I was sufficient for abolishing radioresistance. Treatment with either API-2 or Cdk4-I was also effective in suppressing resistance to cis-platinum (II)-diamine-dichloride in the cells with acquired radioresistance. Interestingly, the radiosensitizing effect of API-2 was canceled by overexpression of cyclin D1 whereas Cdk4-I was still able to sensitize cells with cyclin D1 overexpression. Conclusion: Cyclin D1/Cdk4 is a critical target of the AKT survival signaling pathway responsible for tumor radioresistance. Targeting the AKT/GSK3β/cyclin D1/Cdk4 pathway would provide a novel approach to improve fractionated RT and would have an impact on tumor eradication in

Analysis of signal transducer and activator of transcription 3 (Stat 3) pathway in multiple myeloma: Stat 3 activation and cyclin D1 dysregulation are mutually exclusive events.

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Quintanilla-Martinez, Leticia; Kremer, Marcus; Specht, Katja; Calzada-Wack, Julia; Nathrath, Michaela; Schaich, Robert; Höfler, Heinz; Fend, Falko

2003-05-01

The signal transducer and activator of transcription molecules (Stats) play key roles in cytokine-induced signal transduction. Recently, it was proposed that constitutively activated Stat 3 (Stat 3 phosphorylated) contributes to the pathogenesis of multiple myeloma (MM) by preventing apoptosis and inducing proliferation. The study aim was to investigate Stat 3 activation in a series of multiple myeloma (MM) cases and its effect on downstream targets such as the anti-apoptotic proteins Bcl-xL, Mcl-1, and Bcl-2, and the cell-cycle protein cyclin D1. Forty-eight cases of MM were analyzed. Immunohistochemistry was performed on paraffin sections using antibodies against cyclin D1, Bcl-2, Bcl-xL, Mcl-1, p21, Stat 3, and Stat 3 phosphorylated (P). Their specificity was corroborated by Western blot analysis using eight human MM cell lines as control. The proliferation rate was assessed with the antibody MiB1. In addition, the mRNA levels of cyclin D1 and Stat 3 were determined by quantitative real-time reverse transcriptase-polymerase chain reaction of paraffin-embedded microdissected tissue. Three different groups determined by the expression of Stat 3P and cyclin D1 (protein and mRNA) were identified: group 1, Stat 3-activated (23 cases, 48%). All cases revealed nuclear expression of Stat 3P. No elevation of Stat 3 mRNA was identified in any of the cases. Three cases in this group showed intermediate to low cyclin D1 protein and mRNA expression. Group 2 included 15 (31%) cases with cyclin D1 staining and lack of Stat 3P. All cases showed intermediate to high levels of cyclin D1 mRNA expression. Group 3 included 10 (21%) cases with no expression of either cyclin D1 or Stat 3P. High levels of anti-apoptotic proteins Bcl-xL and Mcl-1 were identified in 89% and 100% of all cases, respectively. In contrast to Bcl-xL and Mcl-1, the expression of Bcl-2 showed an inverse correlation with proliferation rate (P: 0.0003). No significant differences were found between the three

Increased expression of cyclin B1 mRNA coincides with diminished G{sub 2}-phase arrest in irradiated HeLa cells treated with staurosporine or caffeine

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Bernhard, E.J.; Maity, A.; McKenna, W.G.; Muschel, R.J. [Univ. of Pennsylvania School of Medicine, Philadelphia, PA (United States)

1994-12-01

The irradiation of cells results in delayed progression through the G{sub 2} phase of the cell cycle. Treatment of irradiated HeLa cells with caffeine greatly reduces the G{sub 2}-phase delay, while caffeine does not alter progression of cells through the cell cycle in unirradiated cells. In this report we demonstrate that treatment of HeLa cells with the kinase inhibitor staurosporine, but not with the inhibitor H7, also results in a reduction of the G{sub 2}-phase arrest after irradiation. Cell cycle progression in unirradiated cells is unaffected by 4.4 nM (2ng/ml) staurosporine, which releases the radiation-induced G{sub 2}-phase arrest. In HeLa cells, the G{sub 2}-phase delay after irradiation in S phase is accompanied by decreased expression of cyclin B1 mRNA. Coincident with the reduction in G{sub 2}-phase delay, we observed an increase in cyclin B1 mRNA accumulation in irradiated, staurosporine-treated cells compared to cells treated with irradiation alone. Caffeine treatment of irradiated HeLa cells also resulted in an elevation in the levels of cyclin B1 message. These results support the hypothesis that diminished cyclin B1 mRNA levels influence G{sub 2}-phase arrest to some degree. The findings that both staurosporine and caffeine treatments reverse the depression in cyclin B1 expression suggest that these two compounds may act on a common pathway of cell cycle control in response to radiation injury. 33 refs., 6 figs.

Clinical significance of cyclin-dependent kinase inhibitor p27Kip1 expression and proliferation in non-Hodgkin's lymphoma

DEFF Research Database (Denmark)

Møller, Michael Boe; Skjødt, Karsten; Mortensen, Leif Spange

1999-01-01

The cyclin-dependent kinase inhibitor p27Kip1 is a negative cell cycle regulator linking extracellular growth-regulatory signals to the cell cycle machinery in G1. We investigated the pattern and prognostic value of p27Kip1 expression in a population-based group of 203 non-Hodgkin's lymphoma (NHL...... between p27Kip1 and Ki-67 expression. Low expression of p27Kip1, defined as nuclear p27Kip1 expression in lymphomas behaved differently as those with low p27Kip1...... expression tended to do better. Likewise, a high proliferation rate (Ki-67 >40%) was associated with poor survival in indolent and aggressive lymphomas. Multivariate analysis using the proportional hazards model showed that only p27Kip1, and not Ki-67, maintained independent prognostic significance...

A critical role for FBXW8 and MAPK in cyclin D1 degradation and cancer cell proliferation.

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Hiroshi Okabe

2006-12-01

Full Text Available Cyclin D1 regulates G1 progression. Its transcriptional regulation is well understood. However, the mechanism underlying cyclin D1 ubiquitination and its subsequent degradation is not yet clear. We report that cyclin D1 undergoes increased degradation in the cytoplasm during S phase in a variety of cancer cells. This is mediated by phosphorylation at Thr286 through the activity of the Ras/Raf/MEK/ERK cascade and the F-box protein FBXW8, which is an E3 ligase. The majority of FBXW8 is expressed in the cytoplasm during G1 and S phase. In contrast, cyclin D1 accumulates in the nucleus during G1 phase and exits into the cytoplasm in S phase. Increased cyclin D1 degradation is linked to association with FBXW8 in the cytoplasm, and enhanced phosphorylation of cyclin D1 through sustained ERK1/2 signaling. Depletion of FBXW8 caused a significant accumulation of cyclin D1, as well as sequestration of CDK1 in the cytoplasm. This resulted in a severe reduction of cell proliferation. These effects could be rescued by constitutive nuclear expression of cyclin D1-T286A. Thus, FBXW8 plays an essential role in cancer cell proliferation through proteolysis of cyclin D1. It may present new opportunities to develop therapies targeting destruction of cyclin D1 or its regulator E3 ligase selectively.

Glucose Induces Mouse β-Cell Proliferation via IRS2, MTOR, and Cyclin D2 but Not the Insulin Receptor

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Stamateris, Rachel E.; Sharma, Rohit B.; Kong, Yahui; Ebrahimpour, Pantea; Panday, Deepika; Ranganath, Pavana; Zou, Baobo; Levitt, Helena; Parambil, Nisha Abraham; O’Donnell, Christopher P.; García-Ocaña, Adolfo

2016-01-01

An important goal in diabetes research is to understand the processes that trigger endogenous β-cell proliferation. Hyperglycemia induces β-cell replication, but the mechanism remains debated. A prime candidate is insulin, which acts locally through the insulin receptor. Having previously developed an in vivo mouse hyperglycemia model, we tested whether glucose induces β-cell proliferation through insulin signaling. By using mice lacking insulin signaling intermediate insulin receptor substrate 2 (IRS2), we confirmed that hyperglycemia-induced β-cell proliferation requires IRS2 both in vivo and ex vivo. Of note, insulin receptor activation was not required for glucose-induced proliferation, and insulin itself was not sufficient to drive replication. Glucose and insulin caused similar acute signaling in mouse islets, but chronic signaling differed markedly, with mammalian target of rapamycin (MTOR) and extracellular signal–related kinase (ERK) activation by glucose and AKT activation by insulin. MTOR but not ERK activation was required for glucose-induced proliferation. Cyclin D2 was necessary for glucose-induced β-cell proliferation. Cyclin D2 expression was reduced when either IRS2 or MTOR signaling was lost, and restoring cyclin D2 expression rescued the proliferation defect. Human islets shared many of these regulatory pathways. Taken together, these results support a model in which IRS2, MTOR, and cyclin D2, but not the insulin receptor, mediate glucose-induced proliferation. PMID:26740601

Apoptosis, proliferation and p53, cyclin D1, and retinoblastoma gene expression in relation to radiation response in transitional cell carcinoma of the bladder

International Nuclear Information System (INIS)

Moonen, Luc; Ong, Francisca; Gallee, Maarten; Verheij, Marcel; Horenblas, Simon; Hart, Augustinus A.M.; Bartelink, Harry

2001-01-01

Purpose: To determine whether the apoptotic index, the Ki67 index, and the expression of the p53, cyclin D1, and retinoblastoma genes correlate with local control, overall survival, and time to distant metastases in invasive bladder cancer treated with external beam radiation. Methods and Materials: Paraffin-embedded pretreatment biopsies from 83 patients with invasive transitional cell carcinoma of the bladder were scored morphologically for apoptosis and immunohistochemically for Ki67, p53, cyclin D1, and retinoblastoma gene expression. Survival analysis methods were used to assess overall survival, local control, and freedom from distant metastases. A multiple proportional hazard (PH) regression analysis was performed to study the prognostic value of the above mentioned biologic parameters (all divided into two categories, except Ki67) in addition to classical prognostic factors such as T stage, histologic grade, multifocality of the tumor, and completeness of transurethral resection. All patients were treated with external beam radiation as sole treatment. Median follow-up for the 19 patients still living was 7.5 years. Results: Apoptotic index varied from 0% to 3.4% with a mean of 0.8% and a median of 0.6%. Ki67 index varied from 0% to 60% with a mean of 14% and a median of 12%. P53 protein was detectable in 61% of the tumors. Overexpression of cyclin D1 was observed in 39% of the tumors and loss of retinoblastoma protein in 23% of the tumors. High Ki67 index was found to be significantly associated with p53 expression (p=0.04) and cyclin D1 overexpression (p=0.023). Cyclin D1 overexpression was found more often in Rb-positive tumors than in Rb-negative tumors (p=0.006). Other associations between the markers are less clear. Biologic markers were not correlated with T stage or grade. In the PH analysis local control was found to be significantly better for tumors with wild-type p53 (p=0.028). Also, tumors with an apoptotic index above the median value (0

Identification of an hexapeptide that binds to a surface pocket in cyclin A and inhibits the catalytic activity of the complex cyclin-dependent kinase 2-cyclin A.

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Canela, Núria; Orzáez, Mar; Fucho, Raquel; Mateo, Francesca; Gutierrez, Ricardo; Pineda-Lucena, Antonio; Bachs, Oriol; Pérez-Payá, Enrique

2006-11-24

The protein-protein complexes formed between different cyclins and cyclin-dependent kinases (CDKs) are central to cell cycle regulation. These complexes represent interesting points of chemical intervention for the development of antineoplastic molecules. Here we describe the identification of an all d-amino acid hexapeptide, termed NBI1, that inhibits the kinase activity of the cyclin-dependent kinase 2 (cdk2)-cyclin A complex through selective binding to cyclin A. The mechanism of inhibition is non-competitive for ATP and non-competitive for protein substrates. In contrast to the existing CDKs peptide inhibitors, the hexapeptide NBI1 interferes with the formation of the cdk2-cyclin A complex. Furthermore, a cell-permeable derivative of NBI1 induces apoptosis and inhibits proliferation of tumor cell lines. Thus, the NBI1-binding site on cyclin A may represent a new target site for the selective inhibition of activity cdk2-cyclin A complex.

Growth inhibition of head and neck squamous cell carcinoma cells by sgRNA targeting the cyclin D1 mRNA based on TRUE gene silencing.

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Satoshi Iizuka

Full Text Available Head and neck squamous cell carcinoma (HNSCC exhibits increased expression of cyclin D1 (CCND1. Previous studies have shown a correlation between poor prognosis of HNSCC and cyclin D1 overexpression. tRNase ZL-utilizing efficacious gene silencing (TRUE gene silencing is one of the RNA-mediated gene expression control technologies that have therapeutic potential. This technology is based on a unique enzymatic property of mammalian tRNase ZL, which is that it can cleave any target RNA at any desired site by recognizing a pre-tRNA-like complex formed between the target RNA and an artificial small guide RNA (sgRNA. In this study, we designed several sgRNAs targeting human cyclin D1 mRNA to examine growth inhibition of HNSCC cells. Transfection of certain sgRNAs decreased levels of cyclin D1 mRNA and protein in HSC-2 and HSC-3 cells, and also inhibited their proliferation. The combination of these sgRNAs and cisplatin showed more than additive inhibition of cancer cell growth. These findings demonstrate that TRUE gene silencing of cyclin D1 leads to inhibition of the growth of HNSCC cells and suggest that these sgRNAs alone or combined with cisplatin may be a useful new therapy for HNSCCs.

High expression of BAG3 predicts a poor prognosis in human medulloblastoma.

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Yang, Dong; Zhou, Ji; Wang, Hao; Wang, Yutao; Yang, Ge; Zhang, Yundong

2016-10-01

Bcl2-associated athanogene 3 (BAG3), a co-chaperone of the heat shock protein (Hsp) 70, regulates various physiological and pathological processes. However, its role in human medulloblastoma has not been clarified. First of all, the expression of BAG3 was examined in formalin-fixed, paraffin-embedded specimens by immunohistochemical staining. And then, the prognostic role of BAG3 was analyzed in 51 medulloblastoma samples. Finally, the roles of BAG3 in the proliferation, migration, and invasion of Daoy medulloblastoma cell were investigated using a specific short hairpin RNA (shRNA). The expression of BAG3 in medulloblastoma tissues was higher than nontumorous samples. Furthermore, BAG3 overexpression significantly correlated with poor prognosis of patients with medulloblastoma. The overall survival and tumor-free survival in patients with BAG3 low expression were higher than high expression. Univariate and multivariate analysis showed that BAG3 overexpression was an independent prognostic marker for medulloblastoma. After the BAG3 knockdown, the Daoy cells exhibited decreased the ability to proliferate and form neurosphere. The preliminary mechanism study showed that overexpression of BAG3 might facilitate the cell cycle transition from G1 to S phase by modulating the cyclin-dependent kinase 2 (CDK2) and cyclin E expression. Additionally, we found that BAG3 might enhance the medulloblastoma cell migratory and invasive ability. In summary, BAG3 overexpression may regulate the survival and invasive properties of medulloblastoma and may serve as a potential therapy target for medulloblastoma.

SCF^{Cyclin F}-dependent degradation of CDC6 suppresses DNA re-replication

DEFF Research Database (Denmark)

Walter, David; Hoffmann, Saskia; Komseli, Eirini-Stavroula

2016-01-01

interact through defined sequence motifs that promote CDC6 ubiquitylation and degradation. Absence of Cyclin F or expression of a stable mutant of CDC6 promotes re-replication and genome instability in cells lacking the CDT1 inhibitor Geminin. Together, our work reveals a novel SCF(Cyclin F...

c-Jun induces apoptosis of starved BM2 monoblasts by activating cyclin A-CDK2

International Nuclear Information System (INIS)

Vanhara, Petr; Bryja, Vitezslav; Horvath, Viktor; Kozubik, Alois; Hampl, Ales; Smarda, Jan

2007-01-01

c-Jun is one of the major components of the activating protein-1 (AP-1), the transcription factor that participates in regulation of proliferation, differentiation, and apoptosis. In this study, we explored functional interactions of the c-Jun protein with several regulators of the G1/S transition in serum-deprived v-myb-transformed chicken monoblasts BM2. We show that the c-Jun protein induces expression of cyclin A, thus up-regulating activity of cyclin A-associated cyclin-dependent kinase 2 (CDK2), and causing massive programmed cell death of starved BM2cJUN cells. Specific inhibition of CDK2 suppresses frequency of apoptosis of BM2cJUN cells. We conclude that up-regulation of cyclin A expression and CDK2 activity can represent important link between the c-Jun protein, cell cycle machinery, and programmed cell death pathway in leukemic cells

Oncolytic adenovirus targeting cyclin E overexpression repressed tumor growth in syngeneic immunocompetent mice

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Cheng, Pei-Hsin; Rao, Xiao-Mei; Wechman, Stephen L.; Li, Xiao-Feng; McMasters, Kelly M.; Zhou, Heshan Sam

2015-01-01

Clinical trials have indicated that preclinical results obtained with human tumor xenografts in mouse models may overstate the potential of adenovirus (Ad)-mediated oncolytic therapies. We have previously demonstrated that the replication of human Ads depends on cyclin E dysregulation or overexpression in cancer cells. ED-1 cell derived from mouse lung adenocarcinomas triggered by transgenic overexpression of human cyclin E may be applied to investigate the antitumor efficacy of oncolytic Ads. Ad-cycE was used to target cyclin E overexpression in ED-1 cells and repress tumor growth in a syngeneic mouse model for investigation of oncolytic virotherapies. Murine ED-1 cells were permissive for human Ad replication and Ad-cycE repressed ED-1 tumor growth in immunocompetent FVB mice. ED-1 cells destroyed by oncolytic Ads in tumors were encircled in capsule-like structures, while cells outside the capsules were not infected and survived the treatment. Ad-cycE can target cyclin E overexpression in cancer cells and repress tumor growth in syngeneic mouse models. The capsule structures formed after Ad intratumoral injection may prevent viral particles from spreading to the entire tumor. The online version of this article (doi:10.1186/s12885-015-1731-x) contains supplementary material, which is available to authorized users

Modifications in cell cycle kinetics and in expression of G1 phase-regulating proteins in human amniotic cells after exposure to electromagnetic fields and ionizing radiation.

Science.gov (United States)

Lange, S; Viergutz, T; Simkó, M

2004-10-01

Low-frequency electromagnetic fields are suspected of being involved in carcinogenesis, particularly in processes that could be related to cancer promotion. Because development of cancer is associated with deregulated cell growth and we previously observed a magnetic field-induced decrease in DNA synthesis [Lange et al. (2002) Alterations in the cell cycle and in the protein level of cyclin D1p, 21CIP1, and p16INK4a after exposure to 50 HZ. MF in human cells. Radiat. Environ. Biophys.41, 131], this study aims to document the influence of 50 Hz, 1 mT magnetic fields (MF), with or without initial gamma-ionizing radiation (IR), on the following cell proliferation-relevant parameters in human amniotic fluid cells (AFC): cell cycle distribution, expression of the G1 phase-regulating proteins Cdk4, cyclin D1, p21CIP1 and p16INK4a, and Cdk4 activity. While IR induced a G1 delay and a dose-dependent G2 arrest, no discernible changes in cell cycle kinetics were observed due to MF exposure. However, a significant decrease in the protein expression of cyclin D1 and an increase in p21CIP1- and p16INK4a-expression could be detected after exposure to MF alone. IR-exposure caused an augmentation of p21CIP1- and p16INK4a- levels as well, but did not alter cyclin D1 expression. A slight diminution of Cdk4 activity was noticed after MF exposure only, indicating that Cdk4 appears not to act as a mediator of MF- or IR-induced changes in the cell cycle of AFC cells. Co-exposure to MF/IR affected neither cell cycle distribution nor protein expression or kinase activity additionally or synergistically, and therefore MF seems not to modify the mutagenic potency of IR.

Expression of Cyclin D1 protein and CCN DI with PNKP genes in peripheral blood mononuclear cells in clean-up worker of Chernobyl accident with different state of immune system

International Nuclear Information System (INIS)

Bazika, D.A.; Kubashko, A.V.; Yil'jenko, Yi.M.; Belyajev, O.A.; Pleskach, O.Ya.

2015-01-01

The investigate of Cyclin D1+cells levels changes, associated CCND1 and PNKP genes in peripheral blood mononuclear cells in cleanup workers of Chornobyl accident with different state of immune system in depends on the dose irradiation. Analyzed data of the nuclear controller of cell cycle- Cyclin D1 protein expression changes and related CCND1 and PNKP genes in peripheral blood mononuclear cells in cleanup workers Chornobyl accident with different status of immune system in remote period after exposure is represented. Reveled changes in expression of Cyclin D1+cells and regulation of related genes may point on possible radiation-associated firm molecular disturbances occurred during elimination of consequences of Chornobyl accident, that could be a potential basis for cell and humoral communicative links breach in immune system result ing in elevation of stochastic effects like oncopathology in cleanup workers of Chornobyl accident in remote peri od after exposure

Cyclin G2 is a centrosome-associated nucleocytoplasmic shuttling protein that influences microtubule stability and induces a p53-dependent cell cycle arrest

International Nuclear Information System (INIS)

Arachchige Don, Aruni S.; Dallapiazza, Robert F.; Bennin, David A.; Brake, Tiffany; Cowan, Colleen E.; Horne, Mary C.

2006-01-01

Cyclin G2 is an atypical cyclin that associates with active protein phosphatase 2A. Cyclin G2 gene expression correlates with cell cycle inhibition; it is significantly upregulated in response to DNA damage and diverse growth inhibitory stimuli, but repressed by mitogenic signals. Ectopic expression of cyclin G2 promotes cell cycle arrest, cyclin dependent kinase 2 inhibition and the formation of aberrant nuclei [Bennin, D. A., Don, A. S., Brake, T., McKenzie, J. L., Rosenbaum, H., Ortiz, L., DePaoli-Roach, A. A., and Horne, M. C. (2002). Cyclin G2 associates with protein phosphatase 2A catalytic and regulatory B' subunits in active complexes and induces nuclear aberrations and a G 1 /S-phase cell cycle arrest. J Biol Chem 277, 27449-67]. Here we report that endogenous cyclin G2 copurifies with centrosomes and microtubules (MT) and that ectopic G2 expression alters microtubule stability. We find exogenous and endogenous cyclin G2 present at microtubule organizing centers (MTOCs) where it colocalizes with centrosomal markers in a variety of cell lines. We previously reported that cyclin G2 forms complexes with active protein phosphatase 2A (PP2A) and colocalizes with PP2A in a detergent-resistant compartment. We now show that cyclin G2 and PP2A colocalize at MTOCs in transfected cells and that the endogenous proteins copurify with isolated centrosomes. Displacement of the endogenous centrosomal scaffolding protein AKAP450 that anchors PP2A at the centrosome resulted in the depletion of centrosomal cyclin G2. We find that ectopic expression of cyclin G2 induces microtubule bundling and resistance to depolymerization, inhibition of polymer regrowth from MTOCs and a p53-dependent cell cycle arrest. Furthermore, we determined that a 100 amino acid carboxy-terminal region of cyclin G2 is sufficient to both direct GFP localization to centrosomes and induce cell cycle inhibition. Colocalization of endogenous cyclin G2 with only one of two GFP-centrin-tagged centrioles, the

CDK1 inhibition facilitates formation of syncytiotrophoblasts and expression of human Chorionic Gonadotropin

KAUST Repository

Ullah, Rahim

2018-05-17

Aims The human placental syncytiotrophoblast (STB) cells play essential roles in embryo implantation and nutrient exchange between the mother and the fetus. STBs are polyploid which are formed by fusion of diploid cytotrophoblast (CTB) cells. Abnormality in STBs formation can result in pregnancy-related disorders. While a number of genes have been associated with CTB fusion the initial events that trigger cell fusion are not well understood. Primary objective of this study was to enhance our understanding about the molecular mechanism of placental cell fusion. Methods FACS and microscopic analysis was used to optimize Forskolin-induced fusion of BeWo cells (surrogate of CTBs) and subsequently, changes in the expression of different cell cycle regulator genes were analyzed through Western blotting and qPCR. Immunohistochemistry was performed on the first trimester placental tissue sections to validate the results in the context of placental tissue. Effect of Cyclin Dependent Kinase 1 (CDK1) inhibitor, RO3306, on BeWo cell fusion was studied by microscopy and FACS, and by monitoring the expression of human Chorionic Gonadotropin (hCG) by Western blotting and qPCR. Results The data showed that the placental cell fusion was associated with down regulation of CDK1 and its associated cyclin B, and significant decrease in DNA replication. Moreover, inhibition of CDK1 by an exogenous inhibitor induced placental cell fusion and expression of hCG. Conclusion Here, we report that the placental cell fusion can be induced by inhibiting CDK1. This study has a high therapeutic significance to manage pregnancy related abnormalities.

Expression of Peroxisome Proferator-Activated Receptor γ (PPARγ in Human Transitional Bladder Cancer and its Role in Inducing Cell Death

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You-Fei Guan

1999-10-01

Full Text Available The present study examined the expression and role of the thiazolidinedione (TZD-activated transcription factor, peroxisome proliferator-activated receptor γ (PPARγ, in human bladder cancers. In situ hybridization shows that PPARγ mRNA is highly expressed in all human transitional epithelial cell cancers (TCCa's studied (n=11. PPARγ was also expressed in five TCCa cell lines as determined by RNase protection assays and immunoblot. Retinoid X receptor α (RXRα, a 9-cis-retinoic acid stimulated (9-cis-RA heterodimeric partner of PPARγ, was also co-expressed in all TCCa tissues and cell lines. Treatment of the T24 bladder cancer cells with the TZD PPARγ agonist troglitazone, dramatically inhibited 3H-thymidine incorporation and induced cell death. Addition of the RXRα ligands, 9-cis-RA or LG100268, sensitized T24 bladder cancer cells to the lethal effect of troglitazone and two other PPARγ activators, ciglitazone and 15-deoxy-Δ12,14-PGJ2 (15dPGJ2. Troglitazone treatment increased expression of two cyclin-dependent kinase inhibitors, p21wAF1/CIP1 and p16INK4, reduced cyclin D1 expression, consistent with G1 arrest. Troglitazone also induced an endogenous PPARγ target gene in T24 cells, adipocyte-type fatty acid binding protein (A-FABP, the expression of which correlates with bladder cancer differentiation. In situ hybridization shows that A-FABP expression is localized to normal uroepithelial cells as well as some TCCa's. Taken together, these results demonstrate that PPARγ is expressed in human TCCa where it may play a role in regulating TCCa differentiation and survival, thereby providing a potential target for therapy of uroepithelial cancers.

F-box protein FBXL2 targets cyclin D2 for ubiquitination and degradation to inhibit leukemic cell proliferation

Science.gov (United States)

Chen, Bill B.; Glasser, Jennifer R.; Coon, Tiffany A.; Zou, Chunbin; Miller, Hannah L.; Fenton, Moon; McDyer, John F.; Boyiadzis, Michael

2012-01-01

Hematologic maligancies exhibit a growth advantage by up-regulation of components within the molecular apparatus involved in cell-cycle progression. The SCF (Skip-Cullin1-F-box protein) E3 ligase family provides homeostatic feedback control of cell division by mediating ubiquitination and degradation of cell-cycle proteins. By screening several previously undescribed E3 ligase components, we describe the behavior of a relatively new SCF subunit, termed FBXL2, that ubiquitinates and destabilizes cyclin D2 protein leading to G0 phase arrest and apoptosis in leukemic and B-lymphoblastoid cell lines. FBXL2 expression was strongly suppressed, and yet cyclin D2 protein levels were robustly expressed in acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL) patient samples. Depletion of endogenous FBXL2 stabilized cyclin D2 levels, whereas ectopically expressed FBXL2 decreased cyclin D2 lifespan. FBXL2 did not bind a phosphodegron within its substrate, which is typical of other F-box proteins, but uniquely targeted a calmodulin-binding signature within cyclin D2 to facilitate its polyubiquitination. Calmodulin competes with the F-box protein for access to this motif where it bound and protected cyclin D2 from FBXL2. Calmodulin reversed FBXL2-induced G0 phase arrest and attenuated FBXL2-induced apoptosis of lymphoblastoid cells. These results suggest an antiproliferative effect of SCFFBXL2 in lymphoproliferative malignancies. PMID:22323446

Sticky siRNAs targeting survivin and cyclin B1 exert an antitumoral effect on melanoma subcutaneous xenografts and lung metastases

International Nuclear Information System (INIS)

Kedinger, Valerie; Erbacher, Patrick; Bolcato-Bellemin, Anne-Laure; Meulle, Aline; Zounib, Omar; Bonnet, Marie-Elise; Gossart, Jean-Baptiste; Benoit, Elodie; Messmer, Melanie; Shankaranarayanan, Pattabhiraman; Behr, Jean-Paul

2013-01-01

Melanoma represents one of the most aggressive and therapeutically challenging malignancies as it often gives rise to metastases and develops resistance to classical chemotherapeutic agents. Although diverse therapies have been generated, no major improvement of the patient prognosis has been noticed. One promising alternative to the conventional therapeutic approaches currently available is the inactivation of proteins essential for survival and/or progression of melanomas by means of RNA interference. Survivin and cyclin B1, both involved in cell survival and proliferation and frequently deregulated in human cancers, are good candidate target genes for siRNA mediated therapeutics. We used our newly developed sticky siRNA-based technology delivered with linear polyethyleneimine (PEI) to inhibit the expression of survivin and cyclin B1 both in vitro and in vivo, and addressed the effect of this inhibition on B16-F10 murine melanoma tumor development. We confirm that survivin and cyclin B1 downregulation through a RNA interference mechanism induces a blockage of the cell cycle as well as impaired proliferation of B16-F10 cells in vitro. Most importantly, PEI-mediated systemic delivery of sticky siRNAs against survivin and cyclin B1 efficiently blocks growth of established subcutaneaous B16-F10 tumors as well as formation and dissemination of melanoma lung metastases. In addition, we highlight that inhibition of survivin expression increases the effect of doxorubicin on lung B16-F10 metastasis growth inhibition. PEI-mediated delivery of sticky siRNAs targeting genes involved in tumor progression such as survivin and cyclin B1, either alone or in combination with chemotherapeutic drugs, represents a promising strategy for melanoma treatment

Control of G1 in the developing Drosophila eye: rca1 regulates Cyclin A.

Science.gov (United States)

Dong, X; Zavitz, K H; Thomas, B J; Lin, M; Campbell, S; Zipursky, S L

1997-01-01

In the developing eye of Drosophila melanogaster, cells become synchronized in the G1 phase of the cell cycle just prior to the onset of cellular differentiation and morphogenesis. In roughex (rux) mutants, cells enter S phase precociously because of ectopic activation of a Cyclin A/Cdk complex in early G1. This leads to defects in cell fate and pattern formation, and results in abnormalities in the morphology of the adult eye. A screen for dominant suppressors of the rux eye phenotype led to the identification of mutations in cyclin A, string (cdc25), and new cell cycle genes. One of these genes, regulator of cyclin A (rca1), encodes a novel protein required for both mitotic and meiotic cell cycle progression. rca1 mutants arrest in G2 of embryonic cell cycle 16 with a phenotype very similar to cyclin A loss of function mutants. Expression of rca1 transgenes in G1 or in postmitotic neurons promotes Cyclin A protein accumulation and drives cells into S phase in a Cyclin A-dependent fashion.

Amplification and protein overexpression of cyclin D1: Predictor of occult nodal metastasis in early oral cancer.

Science.gov (United States)

Noorlag, Rob; Boeve, Koos; Witjes, Max J H; Koole, Ronald; Peeters, Ton L M; Schuuring, Ed; Willems, Stefan M; van Es, Robert J J

2017-02-01

Accurate nodal staging is pivotal for treatment planning in early (stage I-II) oral cancer. Unfortunately, current imaging modalities lack sensitivity to detect occult nodal metastases. Chromosomal region 11q13, including genes CCND1, Fas-associated death domain (FADD), and CTTN, is often amplified in oral cancer with nodal metastases. However, evidence in predicting occult nodal metastases is limited. In 158 patients with early tongue and floor of mouth (FOM) squamous cell carcinomas, both CCND1 amplification and cyclin D1, FADD, and cortactin protein expression were correlated with occult nodal metastases. CCND1 amplification and cyclin D1 expression correlated with occult nodal metastases. Cyclin D1 expression was validated in an independent multicenter cohort, confirming the correlation with occult nodal metastases in early FOM cancers. Cyclin D1 is a predictive biomarker for occult nodal metastases in early FOM cancers. Prospective research on biopsy material should confirm these results before implementing its use in routine clinical practice. © 2016 Wiley Periodicals, Inc. Head Neck 39: 326-333, 2017. © 2016 Wiley Periodicals, Inc.

Correlation of cytoplasmic beta-catenin and cyclin D1 overexpression during thyroid carcinogenesis around Semipalatinsk nuclear test site.

Science.gov (United States)

Meirmanov, Serik; Nakashima, Masahiro; Kondo, Hisayoshi; Matsufuji, Reiko; Takamura, Noboru; Ishigaki, Katsu; Ito, Masahiro; Prouglo, Yuri; Yamashita, Shunichi; Sekine, Ichiro

2003-06-01

The Semipalatinsk nuclear test site (SNTS), the Republic of Kazakhstan, has been contaminated by radioactive fallout. The alteration of oncogenic molecules in thyroid cancer around the SNTS was considered worthy of analysis because it presented the potential to elucidate the relationship between radiation exposure and thyroid cancer. This study aimed to analyze both beta-catenin and cyclin D1 expressions in thyroid carcinomas around the SNTS. We examined nine cases of chronic thyroiditis, eight cases of follicular adenomas, and 23 cases of papillary carcinomas. Immunohistochemically, all carcinomas displayed a strong cytosolic beta-catenin expression, while both chronic thyroiditis and follicular adenomas showed a significantly lower cytoplasmic beta-catenin (22.2% and 37.5%, respectively). No cyclin D1 immunoreactivity was evident in chronic thyroiditis. In contrast, 62.5% of follicular adenomas and 87.0% of papillary carcinoma showed cyclin D1 overexpression. Additionally, a strong correlation between cytoplasmic beta-catenin and cyclin D1 expression was suggested in thyroid tumors. This study revealed a higher prevalence of both aberrant beta-catenin expression and cyclin D1 overexpression in papillary thyroid cancers around the SNTS than sporadic cases. The analysis of the alteration of the Wnt signaling-related molecules in thyroid cancer around the SNTS may be important to gain an insight into radiation-induced thyroid tumorigenesis.

Fbw7α and Fbw7γ Collaborate To Shuttle Cyclin E1 into the Nucleolus for Multiubiquitylation

Science.gov (United States)

Bhaskaran, Nimesh; van Drogen, Frank; Ng, Hwee-Fang; Kumar, Raman; Ekholm-Reed, Susanna; Peter, Matthias

2013-01-01

Cyclin E1, an activator of cyclin-dependent kinase 2 (Cdk2) that promotes replicative functions, is normally expressed periodically within the mammalian cell cycle, peaking at the G1-S-phase transition. This periodicity is achieved by E2F-dependent transcription in late G1 and early S phases and by ubiquitin-mediated proteolysis. The ubiquitin ligase that targets phosphorylated cyclin E is SCFFbw7 (also known as SCFCdc4), a member of the cullin ring ligase (CRL) family. Fbw7, a substrate adaptor subunit, is expressed as three splice-variant isoforms with different subcellular distributions: Fbw7α is nucleoplasmic but excluded from the nucleolus, Fbw7β is cytoplasmic, and Fbw7γ is nucleolar. Degradation of cyclin E in vivo requires SCF complexes containing Fbw7α and Fbw7γ, respectively. In vitro reconstitution showed that the role of SCFFbw7α in cyclin E degradation, rather than ubiquitylation, is to serve as a cofactor of the prolyl cis-trans isomerase Pin1 in the isomerization of a noncanonical proline-proline bond in the cyclin E phosphodegron. This isomerization is required for subsequent binding and ubiquitylation by SCFFbw7γ. Here we show that Pin1-mediated isomerization of the cyclin E phosphodegron and subsequent binding to Fbw7γ drive nucleolar localization of cyclin E, where it is ubiquitylated by SCFFbw7γ prior to its degradation by the proteasome. It is possible that this constitutes a mechanism for rapid inactivation of phosphorylated cyclin E by nucleolar sequestration prior to its multiubiquitylation and degradation. PMID:23109421

Low-molecular-weight cyclin E: the missing link between biology and clinical outcome

International Nuclear Information System (INIS)

Akli, Said; Keyomarsi, Khandan

2004-01-01

Cyclin E, a key mediator of transition during the G 1 /S cellular division phase, is deregulated in a wide variety of human cancers. Our group recently reported that overexpression and generation of low-molecular-weight (LMW) isoforms of cyclin E were associated with poor clinical outcome among breast cancer patients. However, the link between LMW cyclin E biology in mediating a tumorigenic phenotype and clinical outcome is unknown. To address this gap in knowledge, we assessed the role of LMW isoforms in breast cancer cells; we found that these forms of cyclin E induced genomic instability and resistance to p21, p27, and antiestrogens in breast cancer. These findings suggest that high levels of LMW isoforms of cyclin E not only can predict failure to endocrine therapy but also are true prognostic indicators because of their influence on cell proliferation and genetic instability

Human cyclin T1 expression ameliorates a T-cell-specific transcriptional limitation for HIV in transgenic rats, but is not sufficient for a spreading infection of prototypic R5 HIV-1 strains ex vivo

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Littman Dan R

2009-01-01

Full Text Available Abstract Background Cells derived from native rodents have limits at distinct steps of HIV replication. Rat primary CD4 T-cells, but not macrophages, display a profound transcriptional deficit that is ameliorated by transient trans-complementation with the human Tat-interacting protein Cyclin T1 (hCycT1. Results Here, we generated transgenic rats that selectively express hCycT1 in CD4 T-cells and macrophages. hCycT1 expression in rat T-cells boosted early HIV gene expression to levels approaching those in infected primary human T-cells. hCycT1 expression was necessary, but not sufficient, to enhance HIV transcription in T-cells from individual transgenic animals, indicating that endogenous cellular factors are critical co-regulators of HIV gene expression in rats. T-cells from hCD4/hCCR5/hCycT1-transgenic rats did not support productive infection of prototypic wild-type R5 HIV-1 strains ex vivo, suggesting one or more significant limitation in the late phase of the replication cycle in this primary rodent cell type. Remarkably, we identify a replication-competent HIV-1 GFP reporter strain (R7/3 YU-2 Env that displays characteristics of a spreading, primarily cell-to-cell-mediated infection in primary T-cells from hCD4/hCCR5-transgenic rats. Moreover, the replication of this recombinant HIV-1 strain was significantly enhanced by hCycT1 transgenesis. The viral determinants of this so far unique replicative ability are currently unknown. Conclusion Thus, hCycT1 expression is beneficial to de novo HIV infection in a transgenic rat model, but additional genetic manipulations of the host or virus are required to achieve full permissivity.

D-type cyclins in adult human testis and testicular cancer

DEFF Research Database (Denmark)

Bartkova, J; Rajpert-de Meyts, E; Skakkebaek, N E

1999-01-01

D-type cyclins are proto-oncogenic components of the 'RB pathway', a G1/S regulatory mechanism centred around the retinoblastoma tumour suppressor (pRB) implicated in key cellular decisions that control cell proliferation, cell-cycle arrest, quiescence, and differentiation. This study focused...

Modulations of benzo[a]pyrene-induced DNA adduct, cyclin D1 and PCNA in oral tissue by 1,4-phenylenebis(methylene)selenocyanate

International Nuclear Information System (INIS)

Chen, Kun-Ming; Sacks, Peter G.; Spratt, Thomas E.; Lin, Jyh-Ming; Boyiri, Telih; Schwartz, Joel; Richie, John P.; Calcagnotto, Ana; Das, Arunangshu; Bortner, James; Zhao, Zonglin; Amin, Shantu; Guttenplan, Joseph; El-Bayoumy, Karam

2009-01-01

Tobacco smoking is an important cause of human oral squamous cell carcinoma (SCC). Tobacco smoke contains multiple carcinogens include polycyclic aromatic hydrocarbons typified by benzo[a]pyrene (B[a]P). Surgery is the conventional treatment approach for SCC, but it remains imperfect. However, chemoprevention is a plausible strategy and we had previously demonstrated that 1,4-phenylenebis(methylene)selenocyanate (p-XSC) significantly inhibited tongue tumors-induced by the synthetic 4-nitroquinoline-N-oxide (not present in tobacco smoke). In this study, we demonstrated that p-XSC is capable of inhibiting B[a]P-DNA adduct formation, cell proliferation, cyclin D1 expression in human oral cells in vitro. In addition, we showed that dietary p-XSC inhibits B[a]P-DNA adduct formation, cell proliferation and cyclin D1 protein expression in the mouse tongue in vivo. The results of this study are encouraging to further evaluate the chemopreventive efficacy of p-XSC initially against B[a]P-induced tongue tumors in mice and ultimately in the clinic.

Interphase APC/C-Cdc20 inhibition by cyclin A2-Cdk2 ensures efficient mitotic entry

DEFF Research Database (Denmark)

Hein, Jamin B; Nilsson, Jakob

2016-01-01

Proper cell-cycle progression requires tight temporal control of the Anaphase Promoting Complex/Cyclosome (APC/C), a large ubiquitin ligase that is activated by one of two co-activators, Cdh1 or Cdc20. APC/C and Cdc20 are already present during interphase but APC/C-Cdc20 regulation during...... this window of the cell cycle, if any, is unknown. Here we show that cyclin A2-Cdk2 binds and phosphorylates Cdc20 in interphase and this inhibits APC/C-Cdc20 activity. Preventing Cdc20 phosphorylation results in pre-mature activation of the APC/C-Cdc20 and several substrates, including cyclin B1 and A2......, are destabilized which lengthens G2 and slows mitotic entry. Expressing non-degradable cyclin A2 but not cyclin B1 restores mitotic entry in these cells. We have thus uncovered a novel positive feedback loop centred on cyclin A2-Cdk2 inhibition of interphase APC/C-Cdc20 to allow further cyclin A2 accumulation...

Involvement of cyclin K posttranscriptional regulation in the formation of Artemia diapause cysts.

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Yang Zhao

Full Text Available BACKGROUND: Artemia eggs tend to develop ovoviviparously to yield nauplius larvae in good rearing conditions; while under adverse situations, they tend to develop oviparously and encysted diapause embryos are formed instead. However, the intrinsic mechanisms regulating this process are not well understood. PRINCIPAL FINDING: This study has characterized the function of cyclin K, a regulatory subunit of the positive transcription elongation factor b (P-TEFb in the two different developmental pathways of Artemia. In the diapause-destined embryo, Western blots showed that the cyclin K protein was down-regulated as the embryo entered dormancy and reverted to relatively high levels of expression once development resumed, consistent with the fluctuations in phosphorylation of position 2 serines (Ser2 in the C-terminal domain (CTD of the largest subunit (Rpb1 of RNA polymerase II (RNAP II. Interestingly, the cyclin K transcript levels remained constant during this process. In vitro translation data indicated that the template activity of cyclin K mRNA stored in the postdiapause cyst was repressed. In addition, in vivo knockdown of cyclin K in developing embryos by RNA interference eliminated phosphorylation of the CTD Ser2 of RNAP II and induced apoptosis by inhibiting the extracellular signal-regulated kinase (ERK survival signaling pathway. CONCLUSIONS/SIGNIFICANCE: Taken together, these findings reveal a role for cyclin K in regulating RNAP II activity during diapause embryo development, which involves the post-transcriptional regulation of cyclin K. In addition, a further role was identified for cyclin K in regulating the control of cell survival during embryogenesis through ERK signaling pathways.

Inhibition of UBE2D3 expression attenuates radiosensitivity of MCF-7 human breast cancer cells by increasing hTERT expression and activity.

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Wenbo Wang

Full Text Available The known functions of telomerase in tumor cells include replenishing telomeric DNA and maintaining cell immortality. We have previously shown the existence of a negative correlation between human telomerase reverse transcriptase (hTERT and radiosensitivity in tumor cells. Here we set out to elucidate the molecular mechanisms underlying regulation by telomerase of radiosensitivity in MCF-7 cells. Toward this aim, yeast two-hybrid (Y2H screening of a human laryngeal squamous cell carcinoma radioresistant (Hep2R cDNA library was first performed to search for potential hTERT interacting proteins. We identified ubiquitin-conjugating enzyme E2D3 (UBE2D3 as a principle hTERT-interacting protein and validated this association biochemically. ShRNA-mediated inhibition of UBE2D3 expression attenuated MCF-7 radiosensitivity, and induced the accumulation of hTERT and cyclin D1 in these cells. Moreover, down-regulation of UBE2D3 increased hTERT activity and cell proliferation, accelerating G1 to S phase transition in MCF-7 cells. Collectively these findings suggest that UBE2D3 participates in the process of hTERT-mediated radiosensitivity in human breast cancer MCF-7 cells by regulating hTERT and cyclin D1.

Establishment of functioning human corneal endothelial cell line with high growth potential.

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Tadashi Yokoi

Full Text Available Hexagonal-shaped human corneal endothelial cells (HCEC form a monolayer by adhering tightly through their intercellular adhesion molecules. Located at the posterior corneal surface, they maintain corneal translucency by dehydrating the corneal stroma, mainly through the Na(+- and K(+-dependent ATPase (Na(+/K(+-ATPase. Because HCEC proliferative activity is low in vivo, once HCEC are damaged and their numbers decrease, the cornea begins to show opacity due to overhydration, resulting in loss of vision. HCEC cell cycle arrest occurs at the G1 phase and is partly regulated by cyclin-dependent kinase inhibitors (CKIs in the Rb pathway (p16-CDK4/CyclinD1-pRb. In this study, we tried to activate proliferation of HCEC by inhibiting CKIs. Retroviral transduction was used to generate two new HCEC lines: transduced human corneal endothelial cell by human papillomavirus type E6/E7 (THCEC (E6/E7 and transduced human corneal endothelial cell by Cdk4R24C/CyclinD1 (THCEH (Cyclin. Reverse transcriptase polymerase chain reaction analysis of gene expression revealed little difference between THCEC (E6/E7, THCEH (Cyclin and non-transduced HCEC, but cell cycle-related genes were up-regulated in THCEC (E6/E7 and THCEH (Cyclin. THCEH (Cyclin expressed intercellular molecules including ZO-1 and N-cadherin and showed similar Na(+/K(+-ATPase pump function to HCEC, which was not demonstrated in THCEC (E6/E7. This study shows that HCEC cell cycle activation can be achieved by inhibiting CKIs even while maintaining critical pump function and morphology.

Inhibitor of CDK interacting with cyclin A1 (INCA1) regulates proliferation and is repressed by oncogenic signaling

DEFF Research Database (Denmark)

Baumer, Nicole; Tickenbrock, Lara; Tschanter, Petra

2011-01-01

The cell cycle is driven by the kinase activity of cyclin/CDK complexes which is negatively regulated by CDK inhibitor proteins. Recently, we identified INCA1 as interaction partner and substrate of cyclin A1 in complex with CDK2. On a functional level, we identified a novel cyclin binding site...... in the INCA1 protein. INCA1 inhibited CDK2 activity and cell proliferation. The inihibitory effects depended on the cyclin-interacting domain. Mitogenic and oncogenic signals suppressed INCA1 expression, while it was induced by cell cycle arrest. We established a deletional mouse model that showed increased...... CDK2 activity in spleen with altered spleen architecture in Inca1-/- mice. Inca1-/- embryonic fibroblasts showed an increase in the fraction of S-phase cells. Furthermore, blasts from ALL and AML patients expressed significantly reduced INCA1 levels highlighting its relevance for growth control...

Neuron-derived orphan receptor 1 promoted human pulmonary artery smooth muscle cells proliferation.

Science.gov (United States)

Wang, Chang-Guo; Lei, Wei; Li, Chang; Zeng, Da-Xiong; Huang, Jian-An

2015-05-01

As a transcription factor of the nuclear receptor superfamily, neuron-derived orphan receptor 1 (NOR1) is induced rapidly in response to various extracellular stimuli. But, it is still unclear its role in pulmonary artery smooth muscle cells proliferation. Human PASMCs were cultured in vitro and stimulated by serum. The special antisense oligodeoxynucleotides (AS-ODNs) were used to knockdown human NOR1 gene expression. Real-time PCR and Western-blot were used to evaluate the gene expression and protein levels. Fetal bovine serum (FBS) induced human PASMCs proliferation in a dose dependent manner. Furthermore, FBS promoted NOR1 gene expression in a dose dependent manner and a time dependent manner. 10% FBS induced a maximal NOR1 mRNA levels at 2 h. FBS also induced a significant higher NOR1 protein levels as compared with control. The NOR1 over-expressed plasmid significantly promoted DNA synthesis and cells proliferation. Moreover, the special AS-ODNs against human NOR1 not only prevented NOR1 expression but also inhibited DNA synthesis and cells proliferation significantly. The NOR1 over-expression plasmid could up-regulate cyclin D1 expression markedly, but the AS-ODNs inhibited cyclin D1 expression significantly. So, we concluded that NOR1 could promote human PASMCs proliferation. Cyclin D1 might be involved in this process.

The p-ERK–p-c-Jun–cyclinD1 pathway is involved in proliferation of smooth muscle cells after exposure to cigarette smoke extract

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Li, Tianjia [Department of Vascular surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005 (China); Song, Ting [Nursing Department of Orthopedics 3rd Ward, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005 (China); Ni, Leng; Yang, Genhuan; Song, Xitao; Wu, Lifei [Department of Vascular surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005 (China); Liu, Bao, E-mail: liubao72@yahoo.com.cn [Department of Vascular surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005 (China); Liu, Changwei, E-mail: liucw@vip.sina.com [Department of Vascular surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005 (China)

2014-10-24

Highlights: • Smooth muscle cells proliferated after exposure to cigarette smoke extract. • The p-ERK, p-c-Jun, and cyclinD1 expressions increased in the process. • The p-ERK inhibitor, U0126, can reverse these effects. • The p-ERK → p-c-Jun → cyclinD1 pathway is involved in the process. - Abstract: An epidemiological survey has shown that smoking is closely related to atherosclerosis, in which excessive proliferation of vascular smooth muscle cells (SMCs) plays a key role. To investigate the mechanism underlying this unusual smoking-induced proliferation, cigarette smoke extract (CSE), prepared as smoke-bubbled phosphate-buffered saline (PBS), was used to induce effects mimicking those exerted by smoking on SMCs. As assessed by Cell Counting Kit-8 detection (an improved MTT assay), SMC viability increased significantly after exposure to CSE. Western blot analysis demonstrated that p-ERK, p-c-Jun, and cyclinD1 expression increased. When p-ERK was inhibited using U0126 (inhibitor of p-ERK), cell viability decreased and the expression of p-c-Jun and cyclinD1 was reduced accordingly, suggesting that p-ERK functions upstream of p-c-Jun and cyclinD1. When a c-Jun over-expression plasmid was transfected into SMCs, the level of cyclinD1 in these cells increased. Moreover, when c-Jun was knocked down by siRNA, cyclinD1 levels decreased. In conclusion, our findings indicate that the p-ERK–p-c-Jun–cyclinD1 pathway is involved in the excessive proliferation of SMCs exposed to CSE.

The p-ERK–p-c-Jun–cyclinD1 pathway is involved in proliferation of smooth muscle cells after exposure to cigarette smoke extract

International Nuclear Information System (INIS)

Li, Tianjia; Song, Ting; Ni, Leng; Yang, Genhuan; Song, Xitao; Wu, Lifei; Liu, Bao; Liu, Changwei

2014-01-01

Highlights: • Smooth muscle cells proliferated after exposure to cigarette smoke extract. • The p-ERK, p-c-Jun, and cyclinD1 expressions increased in the process. • The p-ERK inhibitor, U0126, can reverse these effects. • The p-ERK → p-c-Jun → cyclinD1 pathway is involved in the process. - Abstract: An epidemiological survey has shown that smoking is closely related to atherosclerosis, in which excessive proliferation of vascular smooth muscle cells (SMCs) plays a key role. To investigate the mechanism underlying this unusual smoking-induced proliferation, cigarette smoke extract (CSE), prepared as smoke-bubbled phosphate-buffered saline (PBS), was used to induce effects mimicking those exerted by smoking on SMCs. As assessed by Cell Counting Kit-8 detection (an improved MTT assay), SMC viability increased significantly after exposure to CSE. Western blot analysis demonstrated that p-ERK, p-c-Jun, and cyclinD1 expression increased. When p-ERK was inhibited using U0126 (inhibitor of p-ERK), cell viability decreased and the expression of p-c-Jun and cyclinD1 was reduced accordingly, suggesting that p-ERK functions upstream of p-c-Jun and cyclinD1. When a c-Jun over-expression plasmid was transfected into SMCs, the level of cyclinD1 in these cells increased. Moreover, when c-Jun was knocked down by siRNA, cyclinD1 levels decreased. In conclusion, our findings indicate that the p-ERK–p-c-Jun–cyclinD1 pathway is involved in the excessive proliferation of SMCs exposed to CSE

Value of cyclin A immunohistochemistry for cancer risk stratification in Barrett esophagus surveillance: A multicenter case-control study.

Science.gov (United States)

van Olphen, Sophie H; Ten Kate, Fiebo J C; Doukas, Michail; Kastelein, Florine; Steyerberg, Ewout W; Stoop, Hans A; Spaander, Manon C; Looijenga, Leendert H J; Bruno, Marco J; Biermann, Katharina

2016-11-01

The value of endoscopic Barrett esophagus (BE) surveillance based on histological diagnosis of low-grade dysplasia (LGD) remains debated given the lack of adequate risk stratification. The aim of this study was to evaluate the predictive value of cyclin A expression and to combine these results with our previously reported immunohistochemical p53, AMACR, and SOX2 data, to identify a panel of biomarkers predicting neoplastic progression in BE.We conducted a case-control study within a prospective cohort of 720 BE patients. BE patients who progressed to high-grade dysplasia (HGD, n = 37) or esophageal adenocarcinoma (EAC, n = 13), defined as neoplastic progression, were classified as cases and patients without neoplastic progression were classified as controls (n = 575). Cyclin A expression was determined by immunohistochemistry in all 625 patients; these results were combined with the histological diagnosis and our previous p53, AMACR, and SOX2 data in loglinear regression models. Differences in discriminatory ability were quantified as changes in area under the ROC curve (AUC) for predicting neoplastic progression.Cyclin A surface positivity significantly increased throughout the metaplasia-dysplasia-carcinoma sequences and was seen in 10% (107/1050) of biopsy series without dysplasia, 33% (109/335) in LGD, and 69% (34/50) in HGD/EAC. Positive cyclin A expression was associated with an increased risk of neoplastic progression (adjusted relative risk (RR) 2.4; 95% CI: 1.7-3.4). Increases in AUC were substantial for P53 (+0.05), smaller for SOX2 (+0.014), minor for cyclin A (+0.003), and none for AMARC (0.00).Cyclin A immunopositivity was associated with an increased progression risk in BE patients. However, compared to p53 and SOX2, the incremental value of cyclin A was limited. The use of biomarkers has the potential to significantly improve risk stratification in BE.

Accelerated Stem Growth Rates and Improved Fiber Properties of Loblolly Pine: Functional Analysis Of CyclinD from Pinus taeda

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Dr. John Cairney, School of Biology and Institute of Paper Science and Technology @ Georgia Tech, Georgia Institute of Technology; Dr. Gary Peter, University of Florida; Dr. Ulrika Egertsdotter, Dept. of Forestry, Virgina Tech; Dr. Armin Wagner, New Zealand Forest Research Institute Ltd. (Scion Research.)

2005-11-30

A sustained supply of low-cost, high quality raw materials is essential for the future success of the U.S. forest products industry. To maximize stem (trunk) growth, a fundamental understanding of the molecular mechanisms that regulate cell divisions within the cambial meristem is essential. We hypothesize that auxin levels within the cambial meristem regulate cyclin gene expression and this in turn controls cell cycle progression as occurs in all eukaryotic cells. Work with model plant species has shown that ectopic overexpression of cyclins promotes cell division thereby increasing root growth > five times. We intended to test whether ectopic overexpression of cambial cyclins in the cambial zone of loblolly pine also promotes cell division rates that enhance stem growth rates. Results generated in model annual angiosperm systems cannot be reliably extrapolated to perennial gymnosperms, thus while the generation and development of transgenic pine is time consuming, this is the necessary approach for meaningful data. We succeeded in isolating a cyclin D gene and Clustal analysis to the Arabidopsis cyclin D gene family indicates that it is more closely related to cyclin D2 than D1 or D3 Using this gene as a probe we observed a small stimulation of cyclin D expression in somatic embryo culture upon addition of auxin. We hypothesized that trees with more cells in the vascular cambial and expansion zones will have higher cyclin mRNA levels. We demonstrated that in trees under compressive stress where the rates of cambial divisions are increased on the underside of the stem relative to the top or opposite side, there was a 20 fold increase in the level of PtcyclinD1 mRNA on the compressed side of the stem relative to the opposite. This suggests that higher secondary growth rates correlate with PtcyclinD1 expression. We showed that larger diameter trees show more growth during each year and that the increased growth in loblolly pine trees correlates with more cell

Keratin14 mRNA expression in human pneumocytes during quiescence, repair and disease.

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Marco Confalonieri

Full Text Available The lung alveoli slowly self-renew pneumocytes, but their facultative regeneration capacity is rapidly efficient after an injury, so fibrosis infrequently occurs. We recently observed Keratin 14 (KRT14 expression during diffuse alveolar damage (DAD, but not in controls. We wonder if KRT14 may be a marker of pneumocyte transition from quiescence to regeneration. Quantitative PCR and Western blot analyses highlighted the presence of KRT14 (mRNA and protein only in human lung samples with DAD or interstitial lung disease (ILD. In the exponentially growing cell lines A549 and H441, the mRNA and protein levels of KRT14 peaked at day one after cell seeding and decreased at day two, opposite to what observed for the proliferation marker E2F1. The inverse relation of KRT14 versus E2F1 expression holds true also for other proliferative markers, such as cyclin E1 and cyclin D1. Of interest, we also found that E2F1 silencing caused cell cycle arrest and increased KRT14 expression, whilst E2F1 stimulation induced cell cycle progression and decreased KRT14. KRT14 also increased in proliferative pneumocytes (HPAEpiC just before transdifferentiation. Overall, our results suggest that KRT14 is a viable biomarker of pneumocyte activation, and repair/regeneration. The involvement of KRT14 in regenerative process may suggest a novel pharmaceutical target to accelerate lung repair.

MOLECULAR BASIS OF EPIDERMAL GROWTH FACTOR RECEPTOR AND CYCLIN E EXPRESSION INTERDEPENDENCE IN BASAL-LIKE SUBTYPE OF INVASIVE BREAST CARCINOMA.

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Mariamidze, A; Gogiashvili, L; Khardzeishvili, O; Javakhishvili, T; Makaridze, D

2018-03-01

Aim of the study was the simultaneous assessment of EGFR and Cyclin E in "basal-like" carcinoma group, in order to establish their interactivity in the aspect of the age and grade of the tumor, taking into account the common parallel HER2+ samples. The study involved postoperative and/or biopsy material (paraffin blocks) of 237 patients from archived data, who were operated due to breast cancer (National Cancer Center of Tbilisi, 2008-2012 years). In TNBC group and "basal-like" tumor subgroup expression of ESFR, Cyclin E and Cytokeratins 5/6 and 17 were shown advanced activity of processes and high dependence to patients age. Taking into account all above mentioned, the immunohistochemical profile of "basal-like" type of breast cancer is defined mostly by sensitivity to cytokeratins CK5,6/17 and EGFR. In addition, the defected synthesis and activity of the latter, which is actually observed in "basal-like" carcinoma, leads to increased malignancy grade and mitotic activity, which creates the phenotypic and group characteristics for this type of carcinomas overall.

Cyclin D1 affects epithelial–mesenchymal transition in epithelial ovarian cancer stem cell-like cells

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Jiao J

2013-06-01

Full Text Available Jie Jiao,1,4 Lu Huang,1 Feng Ye,1 MinFeng Shi,2 XiaoDong Cheng,3 XinYu Wang,3 DongXiao Hu,3 Xing Xie,3 WeiGuo Lu31Women's Reproductive Health Laboratory of Zhejiang Province, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, 2Department of Gynaecology and Obstetrics, Changhai Hospital, the Second Military Medical University, Shanghai, 3Women's Reproductive Health Laboratory of Zhejiang Province, Department of Gynecologic Oncology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, 4Department of Gynaecology and Obstetrics, Hangzhou First People's Hospital, Hangzhou, People's Republic of ChinaBackground: The association of cancer stem cells with epithelial–mesenchymal transition (EMT is receiving attention. We found in our previous study that EMT existed from CD24- phenotype cells to their differentiated cells. It was shown that cyclin D1 functioned in sustaining self-renewal independent of CDK4/CDK6 activation, but its effect on the EMT mechanism in ovarian cancer stem cells is unclear.Methods: The anchorage-independent spheroids from ovarian adenocarcinoma cell line 3AO were formed in a serum-free medium. CD24- and CD24+ cells were isolated by fluorescence-activated cell sorting. Cell morphology, viability, apoptosis, and migratory ability were observed. Stem-related molecule Bmi-1, Oct-4 and EMT-related marker E-cadherin, and vimentin expressions were analyzed. Cyclin D1 expression in CD24- phenotype enriched spheroids was knocked down with small interfering RNA, and its effects on cell proliferation, apoptosis, migration ability, and EMT-related phenotype after transfection were observed. Results: In our study, CD24- cells presented stronger proliferative, anti-apoptosis capacity, and migratory ability, than CD24+ cells or parental cells. CD24- cells grew with a scattered spindle-shape within 3 days of culture and transformed into a cobblestone-like shape, identical to CD24+ cells or parental cells at 7

The effect of miR-338-3p on HBx deletion-mutant (HBx-d382 mediated liver-cell proliferation through CyclinD1 regulation.

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Xiaoyu Fu

Full Text Available Hepatitis B Virus (HBV DNA integration and HBV X (HBx deletion mutation occurs in HBV-positive liver cancer patients, and C-terminal deletion in HBx gene mutants are highly associated with hepatocarcinogenesis. Our previous study found that the HBx-d382 deletion mutant (deleted at nt 382-400 can down-regulate miR-338-3p expression in HBx-expressing cells. The aim of the present study is to examine the role of miR-338-3p in the HBx-d382-mediated liver-cell proliferation.We established HBx-expressing LO2 cells by Lipofectamine 2000 transfection. A miR-338-3p mimics or inhibitor was transfected into LO2/HBx-d382 and LO2/HBx cells using miR-NC as a control miRNA. In silico analysis of potential miR-338-3p targets revealed that miR-338-3p could target the cell cycle regulatory protein CyclinD1. To confirm that CyclinD1 is negatively regulated by miR-338-3p, we constructed luciferase reporters with wild-type and mutated CyclinD1-3'UTR target sites for miR-338-3p binding. We examined the CyclinD1 expression by real-time PCR and western blot, and proliferation activity by flow cytometric cell cycle analysis, Edu incorporation, and soft agar colony.HBx-d382 exhibited enhanced proliferation and CyclinD1 expression in LO2 cells. miR-338-3p expression inhibited cell proliferation in LO2/HBx-d382 cells (and LO2/HBx cells, and also negatively regulated CyclinD1 protein expression. Of the two putative miR-338-3p binding sites in the CyclinD1-3'UTR region, the effect of miR-338-3p on the second binding site (nt 2397-2403 was required for the inhibition.miR-338-3p can directly regulate CyclinD1 expression through binding to the CyclinD1-3'UTR region, mainly at nt 2397-2403. Down-regulation of miR-338-3p expression is required for liver cell proliferation in both LO2/HBx and LO2/HBx-d382 mutant cells, although the effect is more pronounced in LO2/HBx-d382 cells. Our study elucidated a novel mechanism, from a new miRNA-regulation perspective, underlying the

Rictor regulates FBXW7-dependent c-Myc and cyclin E degradation in colorectal cancer cells

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Guo, Zheng [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, 1838 Guangzhou Dadao Bei, Guangzhou 510515 (China); Zhou, Yuning [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Evers, B. Mark [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Department of Surgery, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Wang, Qingding, E-mail: qingding.wang@uky.edu [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Department of Surgery, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States)

2012-02-10

Highlights: Black-Right-Pointing-Pointer Rictor associates with FBXW7 to form an E3 complex. Black-Right-Pointing-Pointer Knockdown of rictor decreases ubiquitination of c-Myc and cylin E. Black-Right-Pointing-Pointer Knockdown of rictor increases protein levels of c-Myc and cylin E. Black-Right-Pointing-Pointer Overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. Black-Right-Pointing-Pointer Rictor regulation of c-Myc and cyclin E requires FBXW7. -- Abstract: Rictor (Rapamycin-insensitive companion of mTOR) forms a complex with mTOR and phosphorylates and activates Akt. Activation of Akt induces expression of c-Myc and cyclin E, which are overexpressed in colorectal cancer and play an important role in colorectal cancer cell proliferation. Here, we show that rictor associates with FBXW7 to form an E3 complex participating in the regulation of c-Myc and cyclin E degradation. The Rictor-FBXW7 complex is biochemically distinct from the previously reported mTORC2 and can be immunoprecipitated independently of mTORC2. Moreover, knocking down of rictor in serum-deprived colorectal cancer cells results in the decreased ubiquitination and increased protein levels of c-Myc and cyclin E while overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. Genetic knockout of FBXW7 blunts the effects of rictor, suggesting that rictor regulation of c-Myc and cyclin E requires FBXW7. Our findings identify rictor as an important component of FBXW7 E3 ligase complex participating in the regulation of c-Myc and cyclin E protein ubiquitination and degradation. Importantly, our results suggest that elevated growth factor signaling may contribute to decrease rictor/FBXW7-mediated ubiquitination of c-Myc and cyclin E, thus leading to accumulation of cyclin E and c-Myc in colorectal cancer cells.

Rictor regulates FBXW7-dependent c-Myc and cyclin E degradation in colorectal cancer cells

International Nuclear Information System (INIS)

Guo, Zheng; Zhou, Yuning; Evers, B. Mark; Wang, Qingding

2012-01-01

Highlights: ► Rictor associates with FBXW7 to form an E3 complex. ► Knockdown of rictor decreases ubiquitination of c-Myc and cylin E. ► Knockdown of rictor increases protein levels of c-Myc and cylin E. ► Overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. ► Rictor regulation of c-Myc and cyclin E requires FBXW7. -- Abstract: Rictor (Rapamycin-insensitive companion of mTOR) forms a complex with mTOR and phosphorylates and activates Akt. Activation of Akt induces expression of c-Myc and cyclin E, which are overexpressed in colorectal cancer and play an important role in colorectal cancer cell proliferation. Here, we show that rictor associates with FBXW7 to form an E3 complex participating in the regulation of c-Myc and cyclin E degradation. The Rictor–FBXW7 complex is biochemically distinct from the previously reported mTORC2 and can be immunoprecipitated independently of mTORC2. Moreover, knocking down of rictor in serum-deprived colorectal cancer cells results in the decreased ubiquitination and increased protein levels of c-Myc and cyclin E while overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. Genetic knockout of FBXW7 blunts the effects of rictor, suggesting that rictor regulation of c-Myc and cyclin E requires FBXW7. Our findings identify rictor as an important component of FBXW7 E3 ligase complex participating in the regulation of c-Myc and cyclin E protein ubiquitination and degradation. Importantly, our results suggest that elevated growth factor signaling may contribute to decrease rictor/FBXW7-mediated ubiquitination of c-Myc and cyclin E, thus leading to accumulation of cyclin E and c-Myc in colorectal cancer cells.

p21/Cyclin E pathway modulates anticlastogenic function of Bmi-1 in cancer cells

Science.gov (United States)

Deng, Wen; Zhou, Yuan; Tiwari, Agnes FY; Su, Hang; Yang, Jie; Zhu, Dandan; Lau, Victoria Ming Yi; Hau, Pok Man; Yip, Yim Ling; Cheung, Annie LM; Guan, Xin-Yuan; Tsao, Sai Wah

2015-01-01

Apart from regulating stem cell self-renewal, embryonic development and proliferation, Bmi-1 has been recently reported to be critical in the maintenance of genome integrity. In searching for novel mechanisms underlying the anticlastogenic function of Bmi-1, we observed, for the first time, that Bmi-1 positively regulates p21 expression. We extended the finding that Bmi-1 deficiency induced chromosome breaks in multiple cancer cell models. Interestingly, we further demonstrated that knockdown of cyclin E or ectopic overexpression of p21 rescued Bmi-1 deficiency-induced chromosome breaks. We therefore conclude that p21/cyclin E pathway is crucial in modulating the anticlastogenic function of Bmi-1. As it is well established that the overexpression of cyclin E potently induces genome instability and p21 suppresses the function of cyclin E, the novel and important implication from our findings is that Bmi-1 plays an important role in limiting genomic instability in cylin E-overexpressing cancer cells by positive regulation of p21. PMID:25131797

Molecular evolution of cyclin proteins in animals and fungi

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Afonnikov Dmitry A

2011-07-01

Full Text Available Abstract Background The passage through the cell cycle is controlled by complexes of cyclins, the regulatory units, with cyclin-dependent kinases, the catalytic units. It is also known that cyclins form several families, which differ considerably in primary structure from one eukaryotic organism to another. Despite these lines of evidence, the relationship between the evolution of cyclins and their function is an open issue. Here we present the results of our study on the molecular evolution of A-, B-, D-, E-type cyclin proteins in animals and fungi. Results We constructed phylogenetic trees for these proteins, their ancestral sequences and analyzed patterns of amino acid replacements. The analysis of infrequently fixed atypical amino acid replacements in cyclins evidenced that accelerated evolution proceeded predominantly during paralog duplication or after it in animals and fungi and that it was related to aromorphic changes in animals. It was shown also that evolutionary flexibility of cyclin function may be provided by consequential reorganization of regions on protein surface remote from CDK binding sites in animal and fungal cyclins and by functional differentiation of paralogous cyclins formed in animal evolution. Conclusions The results suggested that changes in the number and/or nature of cyclin-binding proteins may underlie the evolutionary role of the alterations in the molecular structure of cyclins and their involvement in diverse molecular-genetic events.

NF-κB-dependent transcriptional upregulation of cyclin D1 exerts cytoprotection against hypoxic injury upon EGFR activation

International Nuclear Information System (INIS)

Chen, Zhi-Dong; Xu, Liang; Tang, Kan-Kai; Gong, Fang-Xiao; Liu, Jing-Quan; Ni, Yin; Jiang, Ling-Zhi; Hong, Jun; Han, Fang; Li, Qian; Yang, Xiang-Hong; Sun, Ren-Hua; Mo, Shi-Jing

2016-01-01

Apoptosis of neural cells is one of the main pathological features in hypoxic/ischemic brain injury. Nuclear factor-κB (NF-κB) might be a potential therapeutic target for hypoxic/ischemic brain injury since NF-κB has been found to be inactivated after hypoxia exposure, yet the underlying molecular mechanisms of NF-κB inactivation are largely unknown. Here we report that epidermal growth factor receptor (EGFR) activation prevents neuron-like PC12 cells apoptosis in response to hypoxia via restoring NF-κB-dependent transcriptional upregulation of cyclin D1. Functionally, EGFR activation by EGF stimulation mitigates hypoxia-induced PC12 cells apoptosis in both dose- and time-dependent manner. Of note, EGFR activation elevates IKKβ phosphorylation, increases IκBα ubiquitination, promotes P65 nuclear translocation and recruitment at cyclin D1 gene promoter as well as upregulates cyclin D1 expression. EGFR activation also abrogates the decrease of IKKβ phosphorylation, reduction of IκBα ubiquitination, blockade of P65 nuclear translocation and recruitment at cyclin D1 gene promoter as well as downregulation of cyclin D1 expression induced by hypoxia. Furthermore, NF-κB-dependent upregulation of cyclin D1 is instrumental for the EGFR-mediated cytoprotection against hypoxic apoptosis. In addition, the dephosphorylation of EGFR induced by either EGF siRNA transfection or anti-HB-EGF neutralization antibody treatment enhances hypoxic cytotoxicity, which are attenuated by EGF administration. Our results highlight the essential role of NF-κB-dependent transcriptional upregulation of cyclin D1 in EGFR-mediated cytoprotective effects under hypoxic preconditioning and support further investigation of EGF in clinical trials of patients with hypoxic/ischemic brain injury. - Highlights: • EGFR activation significantly decreases hypoxia-induced PC12 cells injury. • EGFR activation abrogates the transcriptional repression of cyclin D1 induced by hypoxia in a NF

NF-κB-dependent transcriptional upregulation of cyclin D1 exerts cytoprotection against hypoxic injury upon EGFR activation

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Chen, Zhi-Dong [Department of Critical Care Medicine, The First Affiliated Hospital of Huzhou Normal College, Huzhou 313000, Zhejiang (China); Xu, Liang [Department of Critical Care Medicine, Zhejiang Provincial People’s Hospital, Hangzhou 310000, Zhejiang (China); Tang, Kan-Kai [Department of Critical Care Medicine, The First Affiliated Hospital of Huzhou Normal College, Huzhou 313000, Zhejiang (China); Gong, Fang-Xiao; Liu, Jing-Quan; Ni, Yin; Jiang, Ling-Zhi; Hong, Jun; Han, Fang; Li, Qian; Yang, Xiang-Hong [Department of Critical Care Medicine, Zhejiang Provincial People’s Hospital, Hangzhou 310000, Zhejiang (China); Sun, Ren-Hua, E-mail: jqin168@hotmail.com [Department of Critical Care Medicine, Zhejiang Provincial People’s Hospital, Hangzhou 310000, Zhejiang (China); Mo, Shi-Jing, E-mail: msj860307@163.com [Department of Critical Care Medicine, Zhejiang Provincial People’s Hospital, Hangzhou 310000, Zhejiang (China)

2016-09-10

Apoptosis of neural cells is one of the main pathological features in hypoxic/ischemic brain injury. Nuclear factor-κB (NF-κB) might be a potential therapeutic target for hypoxic/ischemic brain injury since NF-κB has been found to be inactivated after hypoxia exposure, yet the underlying molecular mechanisms of NF-κB inactivation are largely unknown. Here we report that epidermal growth factor receptor (EGFR) activation prevents neuron-like PC12 cells apoptosis in response to hypoxia via restoring NF-κB-dependent transcriptional upregulation of cyclin D1. Functionally, EGFR activation by EGF stimulation mitigates hypoxia-induced PC12 cells apoptosis in both dose- and time-dependent manner. Of note, EGFR activation elevates IKKβ phosphorylation, increases IκBα ubiquitination, promotes P65 nuclear translocation and recruitment at cyclin D1 gene promoter as well as upregulates cyclin D1 expression. EGFR activation also abrogates the decrease of IKKβ phosphorylation, reduction of IκBα ubiquitination, blockade of P65 nuclear translocation and recruitment at cyclin D1 gene promoter as well as downregulation of cyclin D1 expression induced by hypoxia. Furthermore, NF-κB-dependent upregulation of cyclin D1 is instrumental for the EGFR-mediated cytoprotection against hypoxic apoptosis. In addition, the dephosphorylation of EGFR induced by either EGF siRNA transfection or anti-HB-EGF neutralization antibody treatment enhances hypoxic cytotoxicity, which are attenuated by EGF administration. Our results highlight the essential role of NF-κB-dependent transcriptional upregulation of cyclin D1 in EGFR-mediated cytoprotective effects under hypoxic preconditioning and support further investigation of EGF in clinical trials of patients with hypoxic/ischemic brain injury. - Highlights: • EGFR activation significantly decreases hypoxia-induced PC12 cells injury. • EGFR activation abrogates the transcriptional repression of cyclin D1 induced by hypoxia in a NF

Cell cycle regulation of the cyclin A gene promoter is mediated by a variant E2F site

DEFF Research Database (Denmark)

Schulze, A; Zerfass, K; Spitkovsky, D

1995-01-01

Cyclin A is involved in the control of S phase and mitosis in mammalian cells. Expression of the cyclin A gene in nontransformed cells is characterized by repression of its promoter during the G1 phase of the cell cycle and its induction at S-phase entry. We show that this mode of regulation...

Tumor suppressor BLU inhibits proliferation of nasopharyngeal carcinoma cells by regulation of cell cycle, c-Jun N-terminal kinase and the cyclin D1 promoter

International Nuclear Information System (INIS)

Zhang, Xiangning; Liu, Hui; Li, Binbin; Huang, Peichun; Shao, Jianyong; He, Zhiwei

2012-01-01

Tumor suppressor genes function to regulate and block tumor cell proliferation. To explore the mechanisms underlying the tumor suppression of BLU/ZMYND10 gene on a frequently lost human chromosomal region, an adenoviral vector with BLU cDNA insert was constructed. BLU was re-expressed in nasopharyngeal carcinoma cells by transfection or viral infection. Clonogenic growth was assayed; cell cycle was analyzed by flow cytometry-based DNA content detection; c-Jun N-terminal kinase (JNK) and cyclin D1 promoter activities were measured by reporter gene assay, and phosphorylation was measured by immunoblotting. The data for each pair of groups were compared with Student t tests. BLU inhibits clonogenic growth of nasopharyngeal carcinoma cells, arrests cell cycle at G1 phase, downregulates JNK and cyclin D1 promoter activities, and inhibits phosphorylation of c-Jun. BLU inhibits growth of nasopharyngeal carcinoma cells by regulation of the JNK-cyclin D1 axis to exert tumor suppression

Fluorescent peptide biosensor for probing the relative abundance of cyclin-dependent kinases in living cells.

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Laetitia Kurzawa

Full Text Available Cyclin-dependant kinases play a central role in coordinating cell growth and division, and in sustaining proliferation of cancer cells, thereby constituting attractive pharmacological targets. However, there are no direct means of assessing their relative abundance in living cells, current approaches being limited to antigenic and proteomic analysis of fixed cells. In order to probe the relative abundance of these kinases directly in living cells, we have developed a fluorescent peptide biosensor with biligand affinity for CDKs and cyclins in vitro, that retains endogenous CDK/cyclin complexes from cell extracts, and that bears an environmentally-sensitive probe, whose fluorescence increases in a sensitive fashion upon recognition of its targets. CDKSENS was introduced into living cells, through complexation with the cell-penetrating carrier CADY2 and applied to assess the relative abundance of CDK/Cyclins through fluorescence imaging and ratiometric quantification. This peptide biosensor technology affords direct and sensitive readout of CDK/cyclin complex levels, and reports on differences in complex formation when tampering with a single CDK or cyclin. CDKSENS further allows for detection of differences between different healthy and cancer cell lines, thereby enabling to distinguish cells that express high levels of these heterodimeric kinases, from cells that present decreased or defective assemblies. This fluorescent biosensor technology provides information on the overall status of CDK/Cyclin complexes which cannot be obtained through antigenic detection of individual subunits, in a non-invasive fashion which does not require cell fixation or extraction procedures. As such it provides promising perspectives for monitoring the response to therapeutics that affect CDK/Cyclin abundance, for cell-based drug discovery strategies and fluorescence-based cancer diagnostics.

Requirements of cyclin a for mitosis are independent of its subcellular localization.

Science.gov (United States)

Dienemann, Axel; Sprenger, Frank

2004-06-22

Cyclin A (CycA), the only essential mitotic cyclin in Drosophila, is cytoplasmic during interphase and accumulates in the nucleus during prophase. We show that interphase localization is mediated by Leptomycin B (LMB)-sensitive nuclear export. This is a feature shared with human CyclinB1, and it is assumed that nuclear accumulation is necessary for mitotic entry. Here, we tested if the unique mitotic function of CycA requires nuclear accumulation. We fused subcellular localization signals to CycA and tested their mitotic capability. Surprisingly, nuclear accumulation was not required, and even a membrane-tethered form of CycA was able to induce mitosis. We noted that Cyclin B (CycB) protein disappears prematurely in CycA mutants, reminiscent of rca1 mutants. Rca1 is an inhibitor of Fizzy-related-APC/C activity, and in rca1 mutants, mitotic cyclins are degraded in G2 of the 16(th) embryonic cell cycle. Overexpression of Rca1 can restore mitosis in CycA mutants, indicating that the mitotic failure of CycA mutants is caused by premature activation of the APC/C. The essential mitotic function of CycA is therefore not the activation of numerous mitotic substrates by Cdk1-dependent phosphorylation. Rather, CycA-dependent kinase activity is required to inhibit one inhibitor of mitosis, the Fzr protein.

Cyclin D1 in well differentiated thyroid tumour of uncertain malignant potential.

Science.gov (United States)

Lamba Saini, Monika; Weynand, Birgit; Rahier, Jacques; Mourad, Michel; Hamoir, Marc; Marbaix, Etienne

2015-04-18

Encapsulated follicular tumours with equivocal papillary thyroid carcinoma (PTC) type nuclear features continue to remain a challenge despite the recent attempts to classify these borderline lesions. The term 'well differentiated tumour of uncertain malignant potential (WDT-UMP)' was introduced to classify these tumours. The present study aimed to evaluate the role of a cell cycle regulator like cyclin D1 in these tumours along with assessment of other well established PTC markers like galectin-3, HBME-1, CK19. Thirteen cases of metastatic PTC, papillary microcarcinoma and follicular variant of PTC (FVPTC) were identified from a histological review of 510 cases. In addition, 13 cases of a subset of follicular adenomatoid nodules with focal areas showing nuclear features characteristic of PTC, identified as WDT-UMP, were also analyzed. Immunohistochemical analysis of galectin-3, HBME-1, CK19 and the proliferation markers Ki67 and cyclin D1 was performed. Lesions were analyzed for cyclin D1 gene amplification by fluorescent in-situ hybridization. All WDT-UMP lesions showed immunolabelling of cyclin D1, Ki67; 11/ 13 cases showed immunolabelling of CK19; 10/13 cases showed immunolabelling of HBME-1 and 4/13 cases showed immunolabelling of galectin-3. Surrounding benign adenomatoid areas showed no to faint focal staining in all thirteen cases of cyclin D1, HBME-1 and galectin-3. A low rate of cyclin D1 gene amplification was identified in a significant proportion of cells in the WDT-UMP lesions as compared to surrounding benign adenomatoid areas. Increased expression of cyclin D1 and amplification of its gene along with immunolabelling of HBME-1 in WDT-UMP lesions showing cytological features of papillary thyroid carcinoma within follicular adenomatoid nodules suggest that these areas could correspond to a precursor lesion of follicular variant of PTC. Overexpression of cyclin D1, associated with the amplification of the gene suggests that these WDT-UMP lesions are an

Cyclin D2 is a critical mediator of exercise-induced cardiac hypertrophy.

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Luckey, Stephen W; Haines, Chris D; Konhilas, John P; Luczak, Elizabeth D; Messmer-Kratzsch, Antke; Leinwand, Leslie A

2017-12-01

A number of signaling pathways underlying pathological cardiac hypertrophy have been identified. However, few studies have probed the functional significance of these signaling pathways in the context of exercise or physiological pathways. Exercise studies were performed on females from six different genetic mouse models that have been shown to exhibit alterations in pathological cardiac adaptation and hypertrophy. These include mice expressing constitutively active glycogen synthase kinase-3β (GSK-3βS9A), an inhibitor of CaMK II (AC3-I), both GSK-3βS9A and AC3-I (GSK-3βS9A/AC3-I), constitutively active Akt (myrAkt), mice deficient in MAPK/ERK kinase kinase-1 (MEKK1 -/- ), and mice deficient in cyclin D2 (cyclin D2 -/- ). Voluntary wheel running performance was similar to NTG littermates for five of the mouse lines. Exercise induced significant cardiac growth in all mouse models except the cyclin D2 -/- mice. Cardiac function was not impacted in the cyclin D2 -/- mice and studies using a phospho-antibody array identified six proteins with increased phosphorylation (greater than 150%) and nine proteins with decreased phosphorylation (greater than 33% decrease) in the hearts of exercised cyclin D2 -/- mice compared to exercised NTG littermate controls. Our results demonstrate that unlike the other hypertrophic signaling molecules tested here, cyclin D2 is an important regulator of both pathologic and physiological hypertrophy. Impact statement This research is relevant as the hypertrophic signaling pathways tested here have only been characterized for their role in pathological hypertrophy, and not in the context of exercise or physiological hypertrophy. By using the same transgenic mouse lines utilized in previous studies, our findings provide a novel and important understanding for the role of these signaling pathways in physiological hypertrophy. We found that alterations in the signaling pathways tested here had no impact on exercise performance. Exercise

Phosphorylation of Rad9 at serine 328 by cyclin A-Cdk2 triggers apoptosis via interfering Bcl-xL.

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Zhuo Zhan

Full Text Available Cyclin A-Cdk2, a cell cycle regulated Ser/Thr kinase, plays important roles in a variety of apoptoticprocesses. However, the mechanism of cyclin A-Cdk2 regulated apoptosis remains unclear. Here, we demonstrated that Rad9, a member of the BH3-only subfamily of Bcl-2 proteins, could be phosphorylated by cyclin A-Cdk2 in vitro and in vivo. Cyclin A-Cdk2 catalyzed the phosphorylation of Rad9 at serine 328 in HeLa cells during apoptosis induced by etoposide, an inhibitor of topoisomeraseII. The phosphorylation of Rad9 resulted in its translocation from the nucleus to the mitochondria and its interaction with Bcl-xL. The forced activation of cyclin A-Cdk2 in these cells by the overexpression of cyclin A,triggered Rad9 phosphorylation at serine 328 and thereby promoted the interaction of Rad9 with Bcl-xL and the subsequent initiation of the apoptotic program. The pro-apoptotic effects regulated by the cyclin A-Cdk2 complex were significantly lower in cells transfected with Rad9S328A, an expression vector that encodes a Rad9 mutant that is resistant to cyclin A-Cdk2 phosphorylation. These findings suggest that cyclin A-Cdk2 regulates apoptosis through a mechanism that involves Rad9phosphorylation.

Histone deacetylase inhibitor, Trichostatin A induces ubiquitin-dependent cyclin D1 degradation in MCF-7 breast cancer cells

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Charles Coombes R

2006-02-01

Full Text Available Abstract Background Cyclin D1 is an important regulator of G1-S phase cell cycle transition and has been shown to be important for breast cancer development. GSK3β phosphorylates cyclin D1 on Thr-286, resulting in enhanced ubiquitylation, nuclear export and degradation of the cyclin in the cytoplasm. Recent findings suggest that the development of small-molecule cyclin D1 ablative agents is of clinical relevance. We have previously shown that the histone deacetylase inhibitor trichostatin A (TSA induces the rapid ubiquitin-dependent degradation of cyclin D1 in MCF-7 breast cancer cells prior to repression of cyclin D1 gene (CCND1 transcription. TSA treatment also resulted in accumulation of polyubiquitylated GFP-cyclin D1 species and reduced levels of the recombinant protein within the nucleus. Results Here we provide further evidence for TSA-induced ubiquitin-dependent degradation of cyclin D1 and demonstrate that GSK3β-mediated nuclear export facilitates this activity. Our observations suggest that TSA treatment results in enhanced cyclin D1 degradation via the GSK3β/CRM1-dependent nuclear export/26S proteasomal degradation pathway in MCF-7 cells. Conclusion We have demonstrated that rapid TSA-induced cyclin D1 degradation in MCF-7 cells requires GSK3β-mediated Thr-286 phosphorylation and the ubiquitin-dependent 26S proteasome pathway. Drug induced cyclin D1 repression contributes to the inhibition of breast cancer cell proliferation and can sensitize cells to CDK and Akt inhibitors. In addition, anti-cyclin D1 therapy may be highly specific for treating human breast cancer. The development of potent and effective cyclin D1 ablative agents is therefore of clinical relevance. Our findings suggest that HDAC inhibitors may have therapeutic potential as small-molecule cyclin D1 ablative agents.

Gene expression of cyclin-dependent kinase inhibitors and effect of heparin on their expression in mice with hypoxia-induced pulmonary hypertension

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Yu Lunyin; Quinn, Deborah A.; Garg, Hari G.; Hales, Charles A.

2006-01-01

The balance between cell proliferation and cell quiescence is regulated delicately by a variety of mediators, in which cyclin-dependent kinases (CDK) and CDK inhibitors (CDKI) play a very important role. Heparin which inhibits pulmonary artery smooth muscle cell (PASMC) proliferation increases the levels of two CDKIs, p21 and p27, although only p27 is important in inhibition of PASMC growth in vitro and in vivo. In the present study we investigated the expression profile of all the cell cycle regulating genes, including all seven CDKIs (p21, p27, p57, p15, p16, p18, and p19), in the lungs of mice with hypoxia-induced pulmonary hypertension. A cell cycle pathway specific gene microarray was used to profile the 96 genes involved in cell cycle regulation. We also observed the effect of heparin on gene expression. We found that (a) hypoxic exposure for two weeks significantly inhibited p27 expression and stimulated p18 activity, showing a 98% decrease in p27 and 81% increase in p18; (b) other CDKIs, p21, p57, p15, p16, and p19 were not affected significantly in response to hypoxia; (c) heparin treatment restored p27 expression, but did not influence p18; (d) ERK1/2 and p38 were mediators in heparin upregulation of p27. This study provides an expression profile of cell cycle regulating genes under hypoxia in mice with hypoxia-induced pulmonary hypertension and strengthens the previous finding that p27 is the only CDKI involved in heparin regulation of PASMC proliferation and hypoxia-induced pulmonary hypertension

The transcription factor ATF3 is upregulated during chondrocyte differentiation and represses cyclin D1 and A gene transcription

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James Claudine G

2006-09-01

Full Text Available Abstract Background Coordinated chondrocyte proliferation and differentiation are required for normal endochondral bone growth. Transcription factors binding to the cyclicAMP response element (CRE are known to regulate these processes. One member of this family, Activating Tanscription Factor 3 (ATF3, is expressed during skeletogenesis and acts as a transcriptional repressor, but the function of this protein in chondrogenesis is unknown. Results Here we demonstrate that Atf3 mRNA levels increase during mouse chondrocyte differentiation in vitro and in vivo. In addition, Atf3 mRNA levels are increased in response to cytochalasin D treatment, an inducer of chondrocyte maturation. This is accompanied by increased Atf3 promoter activity in cytochalasin D-treated chondrocytes. We had shown earlier that transcription of the cell cycle genes cyclin D1 and cyclin A in chondrocytes is dependent on CREs. Here we demonstrate that overexpression of ATF3 in primary mouse chondrocytes results in reduced transcription of both genes, as well as decreased activity of a CRE reporter plasmid. Repression of cyclin A transcription by ATF3 required the CRE in the cyclin A promoter. In parallel, ATF3 overexpression reduces the activity of a SOX9-dependent promoter and increases the activity of a RUNX2-dependent promoter. Conclusion Our data suggest that transcriptional induction of the Atf3 gene in maturing chondrocytes results in down-regulation of cyclin D1 and cyclin A expression as well as activation of RUNX2-dependent transcription. Therefore, ATF3 induction appears to facilitate cell cycle exit and terminal differentiation of chondrocytes.

Stimulation of pancreatic beta-cell replication by incretins involves transcriptional induction of cyclin D1 via multiple signalling pathways

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Friedrichsen, Birgitte N; Neubauer, Nicole; Lee, Ying C

2006-01-01

pathways leading to mitosis by incretins and cytokines, respectively. The response to both GLP-1 and GIP was completely blocked by the protein kinase A (PKA) inhibitor, H89. In addition, the phosphoinositol 3-kinase (PI3K) inhibitor wortmannin and the mitogen-activated protein kinase kinase (MEK) inhibitor...... and we have previously demonstrated hGH-induced cyclin D2 expression in the insulinoma cell line, INS-1. GLP-1 time-dependently induced the cyclin D1 mRNA and protein levels in INS-1E, whereas the cyclin D2 levels were unaffected. However, minor effect of GLP-1 stimulation was observed on the cyclin D3 m......RNA levels. Transient transfection of a cyclin D1 promoter-luciferase reporter construct into islet monolayer cells or INS-1 cells revealed approximately a 2-3 fold increase of transcriptional activity in response to GLP-1 and GIP, and a 4-7 fold increase in response to forskolin. However, treatment...

The immune privilege of the eye: human retinal pigment epithelial cells selectively modulate T-cell activation in vitro

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Kaestel, Charlotte G; Lovato, Paola; Ødum, Niels

2005-01-01

PURPOSE: To examine the effect of human retinal pigment epithelial (RPE) cells on phytohemagglutinin (PHA) activation of T cells. METHODS: Resting peripheral blood lymphocytes (PBLs) were stimulated with PHA with or without the presence of gamma-irradiated RPE cells. Proliferation and the cell...... in cell culture supernatant was measured by ELISA. RESULTS: Human RPE cells were found to suppress PHA-induced proliferation, cyclin A, IL-2R-alpha and -gamma, and CD71 expression and decrease the production of IL-2; but RPE cells do not inhibit the PHA-induced expression of early activation markers CD69......, MHC class I and II, and of cyclin D of the PBLs. CONCLUSIONS: These results are the first to indicate that RPE cells impede generation of activated T cells by interfering with the induction of high-affinity IL-2R-alphabetagamma, IL-2 production, and the expression of CD71 and cyclin A....

Vitamin K2 and cotylenin A synergistically induce monocytic differentiation and growth arrest along with the suppression of c-MYC expression and induction of cyclin G2 expression in human leukemia HL-60 cells.

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Maniwa, Yasuhisa; Kasukabe, Takashi; Kumakura, Shunichi

2015-08-01

Although all-trans retinoic acid (ATRA) is a standard and effective drug used for differentiation therapy in acute promyelocytic leukemia, ATRA-resistant leukemia cells ultimately emerge during this treatment. Therefore, the development of new drugs or effective combination therapy is urgently needed. We demonstrate that the combined treatment of vitamin K2 and cotylenin A synergistically induced monocytic differentiation in HL-60 cells. This combined treatment also synergistically induced NBT-reducing activity and non-specific esterase-positive cells as well as morphological changes to monocyte/macrophage-like cells. Vitamin K2 and cotylenin A cooperatively inhibited the proliferation of HL-60 cells in short-term and long-term cultures. This treatment also induced growth arrest at the G1 phase. Although 5 µg/ml cotylenin A or 5 µM vitamin K2 alone reduced c-MYC gene expression in HL-60 cells to approximately 45% or 80% that of control cells, respectively, the combined treatment almost completely suppressed c-MYC gene expression. We also demonstrated that the combined treatment of vitamin K2 and cotylenin A synergistically induced the expression of cyclin G2, which had a positive effect on the promotion and maintenance of cell cycle arrest. These results suggest that the combination of vitamin K2 and cotylenin A has therapeutic value in the treatment of acute myeloid leukemia.

Initiation and termination of DNA replication during S phase in relation to cyclins D1, E and A, p21WAF1, Cdt1 and the p12 subunit of DNA polymerase δ revealed in individual cells by cytometry.

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Darzynkiewicz, Zbigniew; Zhao, Hong; Zhang, Sufang; Lee, Marietta Y W T; Lee, Ernest Y C; Zhang, Zhongtao

2015-05-20

During our recent studies on mechanism of the regulation of human DNA polymerase δ in preparation for DNA replication or repair, multiparameter imaging cytometry as exemplified by laser scanning cytometry (LSC) has been used to assess changes in expression of the following nuclear proteins associated with initiation of DNA replication: cyclin A, PCNA, Ki-67, p21(WAF1), DNA replication factor Cdt1 and the smallest subunit of DNA polymerase δ, p12. In the present review, rather than focusing on Pol δ, we emphasize the application of LSC in these studies and outline possibilities offered by the concurrent differential analysis of DNA replication in conjunction with expression of the nuclear proteins. A more extensive analysis of the data on a correlation between rates of EdU incorporation, likely reporting DNA replication, and expression of these proteins, is presently provided. New data, specifically on the expression of cyclin D1 and cyclin E with respect to EdU incorporation as well as on a relationship between expression of cyclin A vs. p21(WAF1) and Ki-67 vs. Cdt1, are also reported. Of particular interest is the observation that this approach makes it possible to assess the temporal sequence of degradation of cyclin D1, p21(WAF1), Cdt1 and p12, each with respect to initiation of DNA replication and with respect to each other. Also the sequence or reappearance of these proteins in G2 after termination of DNA replication is assessed. The reviewed data provide a more comprehensive presentation of potential markers, whose presence or absence marks the DNA replicating cells. Discussed is also usefulness of these markers as indicators of proliferative activity in cancer tissues that may bear information on tumor progression and have a prognostic value.

Molecular characterization and expression analysis of Cyclin B and Cell division cycle 2 in gonads of diploid and triploid bighead catfish, Clarias macrocephalus Günther, 1864

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Anyalak Wachirachaikarn

2017-04-01

Full Text Available This study investigated the differential expression of genes associated with reproduction in sterile triploid and normal diploid bighead catfish (Clarias macrocephalus Günther, 1864. The triploid fish were produced using cold shock and were reared in the same conditions as the diploid counterpart. The histomicrographs showed completely retarded triploid gonads across the samples aged 2–12 mth, whereas the gonads of the diploids were in developing stages during 2–4 mth, reached the early maturing stage at 6 mth, matured at 8 mth and showed signs of atresia at 10–12 mth. In parallel, the full-length cDNAs of cyclin B1 (CmCcnb1; 1539 bp in length with an open reading frame (ORF of 1194 bp corresponding to 397 amino acids and cell division cycle 2 (CmCdc2; 1355 bp, an ORF of 909 bp, 302 amino acids of bighead catfish (C. macrocephalus Günther, 1864 were isolated. Phylogenetic analysis revealed that the newly characterized CmCcnb1 should be regarded as a member of cyclin B1 rather than cyclin B2. The expression level of CmCcnb1 mRNA was limited in different stages of the ovaries and testes of triploids. In diploid ovaries, its expression was significantly higher than that in triploid ovaries in fish aged 2 mth (513.43 ± 82.22 fold and in fish aged 8 mth (2430.87 ± 900.06 fold. The CmCcnb1 level in the testes of diploids was significantly greater than that in triploids in fish aged 2 mth (928.85 ± 208.72 fold. Similarly, expression of CmCdc2 mRNA was also reduced in triploids. Its expression was significantly lower than that in diploid females aged 2 mth (7.66 ± 3.42 fold, 4 mth (59.42 ± 10.50 fold and 8 mth (42.74 ± 8.36 fold. In males, significantly greater expression of CmCdc2 was observed at age 6 mth (58.61 ± 34.64 fold and 8 mth (72.70 ± 4.36 fold diploids compared to triploids. The results illustrated that CmCcnb1 and CmCdc2 are functionally involved in oogenesis and spermatogenesis and reduced

Proteomic analysis of cell proliferation in a human hepatic cell line (HL-7702) induced by perfluorooctane sulfonate using iTRAQ

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Cui, Ruina; Zhang, Hongxia [Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 (China); Guo, Xuejiang [State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029 (China); Cui, Qianqian; Wang, Jianshe [Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 (China); Dai, Jiayin, E-mail: daijy@ioz.ac.cn [Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 (China)

2015-12-15

Highlights: • PFOS stimulates cell proliferation of human liver cell line (HL-7702). • Differential expressed proteins are identified by iTRAQ. • Most of differential proteins caused by PFOS are related to cell proliferation. • Up-regulation of cyclin/cdk by PFOS plays a role in driving cells into cell cycle. - Abstract: Perfluorooctane sulfonate (PFOS) is a commonly used and widely distributed perfluorinated compound proven to cause adverse health outcomes. However, how PFOS affects liver cell proliferation is not well understood. In this experiment, we exposed a human liver cell line (HL-7702) to 50 μM PFOS for 48 h and 96 h. We identified 52 differentially expressed proteins using a quantitative proteomic approach. Among them, 27 were associated with cell proliferation, including hepatoma-derived growth factor (Hdgf) and proliferation biomarkers Mk167 (Ki67) and Top2α. Results from MTT, cell counting, and cell cycle analysis showed low-dose PFOS (<200 μM) stimulated HL-7702 cell viability at 48 h and 96 h, reduced the G0/G1 percentage, and increased the S + G2/M percentage. Moreover, levels of Cyclin D1, Cyclin E2, Cyclin A2, Cyclin B1 and their partner Cdks were elevated, and the expression of regulating proteins like c-Myc, p53, p21 waf/cip1 and Myt1, as well as the phosphorylation levels of p-Wee1(S642), p-Chk1(S345) and p-Chk2(T68), were disturbed. We hypothesized that low-dose PFOS stimulated HL-7702 proliferation by driving cells into G1 through elevating cyclins/cdks expression, and by promoting cell cycle progression through altering other regulating proteins. This research will shed light on the mechanisms behind PFOS-mediated human hepatotoxicity.

Proteomic analysis of cell proliferation in a human hepatic cell line (HL-7702) induced by perfluorooctane sulfonate using iTRAQ

International Nuclear Information System (INIS)

Cui, Ruina; Zhang, Hongxia; Guo, Xuejiang; Cui, Qianqian; Wang, Jianshe; Dai, Jiayin

2015-01-01

Highlights: • PFOS stimulates cell proliferation of human liver cell line (HL-7702). • Differential expressed proteins are identified by iTRAQ. • Most of differential proteins caused by PFOS are related to cell proliferation. • Up-regulation of cyclin/cdk by PFOS plays a role in driving cells into cell cycle. - Abstract: Perfluorooctane sulfonate (PFOS) is a commonly used and widely distributed perfluorinated compound proven to cause adverse health outcomes. However, how PFOS affects liver cell proliferation is not well understood. In this experiment, we exposed a human liver cell line (HL-7702) to 50 μM PFOS for 48 h and 96 h. We identified 52 differentially expressed proteins using a quantitative proteomic approach. Among them, 27 were associated with cell proliferation, including hepatoma-derived growth factor (Hdgf) and proliferation biomarkers Mk167 (Ki67) and Top2α. Results from MTT, cell counting, and cell cycle analysis showed low-dose PFOS (<200 μM) stimulated HL-7702 cell viability at 48 h and 96 h, reduced the G0/G1 percentage, and increased the S + G2/M percentage. Moreover, levels of Cyclin D1, Cyclin E2, Cyclin A2, Cyclin B1 and their partner Cdks were elevated, and the expression of regulating proteins like c-Myc, p53, p21 waf/cip1 and Myt1, as well as the phosphorylation levels of p-Wee1(S642), p-Chk1(S345) and p-Chk2(T68), were disturbed. We hypothesized that low-dose PFOS stimulated HL-7702 proliferation by driving cells into G1 through elevating cyclins/cdks expression, and by promoting cell cycle progression through altering other regulating proteins. This research will shed light on the mechanisms behind PFOS-mediated human hepatotoxicity.

Expression of proteins FGFR3, PI3K, AKT, p21Waf1/Cip1 and cyclins D1 and D3 in patients with T1 bladder tumours: clinical implications and prognostic significance.

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Blanca Pedregosa, A M; Sánchez-González, Á; Carrasco Valiente, J; Ruiz García, J M; Gómez Gómez, E; López Beltrán, A; Requena Tapia, M J

2017-04-01

To determine the differential protein expression of biomarkers FGFR3, PI3K (subunits PI3Kp110α, PI3KClassIII, PI3Kp85), AKT, p21Waf1/Cip1 and cyclins D1 and D3 in T1 bladder cancer versus healthy tissue and to study their potential role as early recurrence markers. This is a prospective study that employed a total of 67 tissue samples (55 cases of T1 bladder tumours that underwent transurethral resection and 12 cases of adjacent healthy mucosa). The protein expression levels were assessed using Western blot, and the means and percentages were compared using Student's t-test and the chi-squared test. The survival analysis was conducted using the Kaplan-Meier method and the log-rank test. Greater protein expression was detected for FGFR3, PI3Kp110α, PI3KClassIII, cyclins D1 and D3 and p21Waf1/Cip1 in the tumour tissue than in the healthy mucosa. However, these differences were not significant for PI3Kp85 and AKT. We observed statistically significant correlations between early recurrence and PI3Kp110α, PI3KClassIII, PI3Kp85 and AKT (P=.003, P=.045, P=.050 and P=.028, respectively), between the tumour type (primary vs. recurrence) and cyclin D3 (P=.001), between the tumour size and FGFR3 (P=.035) and between multifocality and cyclin D1 (P=.039). The survival analysis selected FGFR3 (P=.024), PI3Kp110α (P=.014), PI3KClassIII (P=.042) and AKT (P=.008) as markers of early-recurrence-free survival. There is an increase in protein expression levels in bladder tumour tissue. The overexpression of FGFR3, PI3Kp110α, PI3KClassIII and AKT is associated with increased early-recurrence-free survival for patients with T1 bladder tumours. Copyright © 2016 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

Casticin induced apoptotic cell death and altered associated gene expression in human colon cancer colo 205 cells.

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Shang, Hung-Sheng; Liu, Jia-You; Lu, Hsu-Feng; Chiang, Han-Sun; Lin, Chia-Hain; Chen, Ann; Lin, Yuh-Feng; Chung, Jing-Gung

2017-08-01

Casticin, a polymethoxyflavone, derived from natural plant Fructus Viticis exhibits biological activities including anti-cancer characteristics. The anti-cancer and alter gene expression of casticin on human colon cancer cells and the underlying mechanisms were investigated. Flow cytometric assay was used to measure viable cell, cell cycle and sub-G1 phase, reactive oxygen species (ROS) and Ca 2+ productions, level of mitochondria membrane potential (ΔΨ m ) and caspase activity. Western blotting assay was used to detect expression of protein level associated with cell death. Casticin induced cell morphological changes, decreased cell viability and induced G2/M phase arrest in colo 205 cells. Casticin increased ROS production but decreased the levels of ΔΨ m , and Ca 2+ , increased caspase-3, -8, and -9 activities. The cDNA microarray indicated that some of the cell cycle associated genes were down-regulated such as cyclin-dependent kinase inhibitor 1A (CDKN1A) (p21, Cip1) and p21 protein (Cdc42/Rac)-activated kinase 3 (PAK3). TNF receptor-associated protein 1 (TRAP1), CREB1 (cAMP responsive element binding protein 1) and cyclin-dependent kinase inhibitor 1B (CDKN1B) (p27, Kip1) genes were increased but matrix metallopeptidase 2 (MMP-2), toll-like receptor 4 (TLR4), PRKAR2B (protein kinase, cAMP-dependent, regulatory, type II, bet), and CaMK4 (calcium/calmodulin-dependent protein kinase IV) genes were inhibited. Results suggest that casticin induced cell apoptosis via the activation of the caspase- and/or mitochondria-dependent signaling cascade, the accumulation of ROS and altered associated gene expressions in colo 205 human colon cancer cells. © 2016 Wiley Periodicals, Inc.

[miR-497 suppresses proliferation of human cervical carcinoma HeLa cells by targeting cyclin E1].

Science.gov (United States)

Han, Jiming; Huo, Manpeng; Mu, Mingtao; Liu, Junjun; Zhang, Jing

2014-06-01

To evaluate the effect of miR-497 on proliferation of human cervical carcinoma HeLa cells and target relationship between miR-497 and cyclin E1 (CCNE1). Pre-miR-497 sequences were synthesized and cloned into pcDNATM6.2-GW to construct recombinant plasmid pcDNATM6.2-GW-pre-miR-497 and identified by real-time quantitative PCR (qRT-PCR). In addition, sequences of the wild-type CCNE1 (WT-CCNE1) and mutant CCNE1 (MT-CCNE1) were respectively cloned into pmirGLO vectors. MTT assay was used to explore the impact of miR-497 on the proliferation of HeLa cells. Furthermore, the target effect of miR-497 on the CCNE1 was identified by dual-luciferase reporter assay system, qRT-PCR and Western blotting. The recombinant plasmids pcDNATM6.2-GW-pre-miR-497 and pmirGLO-WT-CCNE1, pmirGLO-MT-CCNE1 were successfully constructed, and the miR-497 expression level in HeLa cells transfected with pre-miR-497 was significantly higher than that in the neg-miR group (PHeLa cells (PHeLa cells with pre-miR-497 transfection (PHeLa cells transfected with pre-miR-497 (PHeLa cells could suppress cell proliferation by targeting CCNE1.

Cyclin A degradation by primate cytomegalovirus protein pUL21a counters its innate restriction of virus replication.

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Nicolas Caffarelli

Full Text Available Cyclin A is critical for cellular DNA synthesis and S phase progression of the cell cycle. Human cytomegalovirus (HCMV can reduce cyclin A levels and block cellular DNA synthesis, and cyclin A overexpression can repress HCMV replication. This interaction has only been previously observed in HCMV as murine CMV does not downregulate cyclin A, and the responsible viral factor has not been identified. We previously reported that the HCMV protein pUL21a disrupted the anaphase-promoting complex (APC, but a point mutant abrogating this activity did not phenocopy a UL21a-deficient virus, suggesting that pUL21a has an additional function. Here we identified a conserved arginine-x-leucine (RxL cyclin-binding domain within pUL21a, which allowed pUL21a to interact with cyclin A and target it for proteasome degradation. Homologous pUL21a proteins from both chimpanzee and rhesus CMVs also contained the RxL domain and similarly degraded cyclin A, indicating that this function is conserved in primate CMVs. The RxL point mutation disabled the virus' ability to block cellular DNA synthesis and resulted in a growth defect similar to pUL21a-deficient virus. Importantly, knockdown of cyclin A rescued growth of UL21a-deficient virus. Together, these data show that during evolution, the pUL21a family proteins of primate CMVs have acquired a cyclin-binding domain that targets cyclin A for degradation, thus neutralizing its restriction on virus replication. Finally, the combined proteasome-dependent degradation of pUL21a and its cellular targets suggests that pUL21a may act as a novel suicide protein, targeting its protein cargos for destruction.

Regulation of Fumonisin B1 Biosynthesis and Conidiation in Fusarium verticillioides by a Cyclin-Like (C-Type) Gene, FCC1†

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Shim, Won-Bo; Woloshuk, Charles P.

2001-01-01

Fumonisins are a group of mycotoxins produced in corn kernels by the plant-pathogenic fungus Fusarium verticillioides. A mutant of the fungus, FT536, carrying a disrupted gene named FCC1 (for Fusarium cyclin C1) resulting in altered fumonisin B1 biosynthesis was generated. FCC1 contains an open reading frame of 1,018 bp, with one intron, and encodes a putative 319-amino-acid polypeptide. This protein is similar to UME3 (also called SRB11 or SSN8), a cyclin C of Saccharomyces cerevisiae, and contains three conserved motifs: a cyclin box, a PEST-rich region, and a destruction box. Also similar to the case for C-type cyclins, FCC1 was constitutively expressed during growth. When strain FT536 was grown on corn kernels or on defined minimal medium at pH 6, conidiation was reduced and FUM5, the polyketide synthase gene involved in fumonisin B1 biosynthesis, was not expressed. However, when the mutant was grown on a defined minimal medium at pH 3, conidiation was restored, and the blocks in expression of FUM5 and fumonisin B1 production were suppressed. Our data suggest that FCC1 plays an important role in signal transduction regulating secondary metabolism (fumonisin biosynthesis) and fungal development (conidiation) in F. verticillioides. PMID:11282612

E-type cyclins modulate telomere integrity in mammalian male meiosis.

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Manterola, Marcia; Sicinski, Piotr; Wolgemuth, Debra J

2016-06-01

We have shown that E-type cyclins are key regulators of mammalian male meiosis. Depletion of cyclin E2 reduced fertility in male mice due to meiotic defects, involving abnormal pairing and synapsis, unrepaired DNA, and loss of telomere structure. These defects were exacerbated by additional loss of cyclin E1, and complete absence of both E-type cyclins produces a meiotic catastrophe. Here, we investigated the involvement of E-type cyclins in maintaining telomere integrity in male meiosis. Spermatocytes lacking cyclin E2 and one E1 allele (E1+/-E2-/-) displayed a high rate of telomere abnormalities but can progress to pachytene and diplotene stages. We show that their telomeres exhibited an aberrant DNA damage repair response during pachynema and that the shelterin complex proteins TRF2 and RAP2 were significantly decreased in the proximal telomeres. Moreover, the insufficient level of these proteins correlated with an increase of γ-H2AX foci in the affected telomeres and resulted in telomere associations involving TRF1 and telomere detachment in later prophase-I stages. These results suggest that E-type cyclins are key modulators of telomere integrity during meiosis by, at least in part, maintaining the balance of shelterin complex proteins, and uncover a novel role of E-type cyclins in regulating chromosome structure during male meiosis.

Anti-inflammatory drugs suppress proliferation and induce apoptosis through altering expressions of cell cycle regulators and pro-apoptotic factors in cultured human osteoblasts

International Nuclear Information System (INIS)

Chang, J.-K.; Li, C.-J.; Liao, H.-J.; Wang, C.-K.; Wang, G.-J.; Ho, M.-L.

2009-01-01

It has been reported that anti-inflammatory drugs (AIDs) inhibited bone repair in animal studies, and suppressed proliferation and induced cell death in rat osteoblast cultures. In this study, we further investigated the molecular mechanisms of AID effects on proliferation and cell death in human osteoblasts (hOBs). We examined the effects of dexamethasone (10 -7 and 10 -6 M), non-selective non-steroidal anti-inflammatory drugs (NSAIDs): indomethacin, ketorolac, piroxicam and diclofenac (10 -5 and 10 -4 M), and COX-2 inhibitor: celecoxib (10 -6 and 10 -5 M) on proliferation, cytotoxicity, cell death, and mRNA and protein levels of cell cycle and apoptosis-related regulators in hOBs. All the tested AIDs significantly inhibited proliferation and arrested cell cycle at G0/G1 phase in hOBs. Celecoxib and dexamethasone, but not non-selective NSAIDs, were found to have cytotoxic effects on hOB, and further demonstrated to induce apoptosis and necrosis (at higher concentration) in hOBs. We further found that indomethacin, celecoxib and dexamethasone increased the mRNA and protein expressions of p27 kip1 and decreased those of cyclin D2 and p-cdk2 in hOBs. Bak expression was increased by celecoxib and dexamethasone, while Bcl-XL level was declined only by dexamethasone. Furthermore, the replenishment of PGE1, PGE2 or PGF2α did not reverse the effects of AIDs on proliferation and expressions of p27 kip1 and cyclin D2 in hOBs. We conclude that the changes in expressions of regulators of cell cycle (p27 kip1 and cyclin D2) and/or apoptosis (Bak and Bcl-XL) by AIDs may contribute to AIDs caused proliferation suppression and apoptosis in hOBs. This effect might not relate to the blockage of prostaglandin synthesis by AIDs

Expression of factors and key components associated with the PI3K signaling pathway in colon cancer.

Science.gov (United States)

Chen, Hua; Gao, Junyi; Du, Zhenhua; Zhang, Xuequn; Yang, Fei; Gao, Wei

2018-04-01

The pathophysiology of colorectal cancer (CRC) has not been fully elucidated. The dysregulation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway frequently contributes to the tumorigenesis and progression of human cancer. The aim of the present study was to explore the expression and clinical significance of a number of associated factors and key components of the PI3K signaling pathway, including phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (p110α), phosphorylated protein kinase B (p-Akt) Ser473, p-mammalian target of rapamycin (mTOR) Ser2448, cyclin D1, cyclin dependent kinase (CDK)4, RELA proto-oncogene, nuclear factor-κβ subunit (p65), Ras and extracellular signal-regulated kinase (ERK)1/2 in human CRC. The expression of target proteins was detected using immunohistochemistry (IHC) in 65 CRC cases and 15 colonic adenoma cases. The association between the expression of target proteins and clinical pathological parameters was analyzed using a χ 2 test. IHC results revealed that the expression of all target proteins was significantly increased in CRC tissues compared with in colonic adenoma tissues (P0.05). Cyclin D1, CDK4 and Ras were revealed to be expressed significantly higher in poorly differentiated CRC compared with moderately differentiated CRC (Pcancer tissues with lymph node metastasis compared with cancer tissues without lymph node metastasis (P<0.05). These results suggest that the target proteins may all participate in the tumorigenesis of CRC. Furthermore, cyclin D1, CDK4, Ras, p65 and ERK1/2 may be important in the progression of CRC. The results of the present study may provide novel predictive factors and therapeutic targets for CRC.

Deficiency of the Cyclin-Dependent Kinase Inhibitor, CDKN1B, Results in Overgrowth and Neurodevelopmental Delay

Science.gov (United States)

Grey, William; Izatt, Louise; Sahraoui, Wafa; Ng, Yiu-Ming; Ogilvie, Caroline; Hulse, Anthony; Tse, Eric; Holic, Roman; Yu, Veronica

2013-01-01

Germline mutations in the cyclin-dependent kinase inhibitor, CDKN1B, have been described in patients with multiple endocrine neoplasia (MEN), a cancer predisposition syndrome with adult onset neoplasia and no additional phenotypes. Here, we describe the first human case of CDKN1B deficiency, which recapitulates features of the murine CDKN1B knockout mouse model, including gigantism and neurodevelopmental defects. Decreased mRNA and protein expression of CDKN1B were confirmed in the proband's peripheral blood, which is not seen in MEN syndrome patients. We ascribed the decreased protein level to a maternally derived deletion on chromosome 12p13 encompassing the CDKN1B locus (which reduced mRNA expression) and a de novo allelic variant (c.-73G>A) in the CDKN1B promoter (which reduced protein translation). We propose a recessive model where decreased dosage of CDKN1B during development in humans results in a neuronal phenotype akin to that described in mice, placing CDKN1B as a candidate gene involved in developmental delay. PMID:23505216

A novel pyrazolo[1,5-a]pyrimidine is a potent inhibitor of cyclin-dependent protein kinases 1, 2, and 9, which demonstrates antitumor effects in human tumor xenografts following oral administration.

Science.gov (United States)

Heathcote, Dean A; Patel, Hetal; Kroll, Sebastian H B; Hazel, Pascale; Periyasamy, Manikandan; Alikian, Mary; Kanneganti, Seshu K; Jogalekar, Ashutosh S; Scheiper, Bodo; Barbazanges, Marion; Blum, Andreas; Brackow, Jan; Siwicka, Alekasandra; Pace, Robert D M; Fuchter, Matthew J; Snyder, James P; Liotta, Dennis C; Freemont, Paul S; Aboagye, Eric O; Coombes, R Charles; Barrett, Anthony G M; Ali, Simak

2010-12-23

Cyclin-dependent protein kinases (CDKs) are central to the appropriate regulation of cell proliferation, apoptosis, and gene expression. Abnormalities in CDK activity and regulation are common features of cancer, making CDK family members attractive targets for the development of anticancer drugs. Here, we report the identification of a pyrazolo[1,5-a]pyrimidine derived compound, 4k (BS-194), as a selective and potent CDK inhibitor, which inhibits CDK2, CDK1, CDK5, CDK7, and CDK9 (IC₅₀= 3, 30, 30, 250, and 90 nmol/L, respectively). Cell-based studies showed inhibition of the phosphorylation of CDK substrates, Rb and the RNA polymerase II C-terminal domain, down-regulation of cyclins A, E, and D1, and cell cycle block in the S and G₂/M phases. Consistent with these findings, 4k demonstrated potent antiproliferative activity in 60 cancer cell lines tested (mean GI₅₀= 280 nmol/L). Pharmacokinetic studies showed that 4k is orally bioavailable, with an elimination half-life of 178 min following oral dosing in mice. When administered at a concentration of 25 mg/kg orally, 4k inhibited human tumor xenografts and suppressed CDK substrate phosphorylation. These findings identify 4k as a novel, potent CDK selective inhibitor with potential for oral delivery in cancer patients.

Evolutionarily conserved transcription factor Apontic controls the G1/S progression by inducing cyclin e during eye development

KAUST Repository

Liu, Qingxin

2014-06-16

During Drosophila eye development, differentiation initiates in the posterior region of the eye disk and progresses anteriorly as a wave marked by the morphogenetic furrow (MF), which demarcates the boundary between anterior undifferentiated cells and posterior differentiated photoreceptors. However, the mechanism underlying the regulation of gene expression immediately before the onset of differentiation remains unclear. Here, we show that Apontic (Apt), which is an evolutionarily conserved transcription factor, is expressed in the differentiating cells posterior to the MF. Moreover, it directly induces the expression of cyclin E and is also required for the G1-to-S phase transition, which is known to be essential for the initiation of cell differentiation at the MF. These observations identify a pathway crucial for eye development, governed by a mechanism in which Cyclin E promotes the G1-to-S phase transition when regulated by Apt.

Evolutionarily conserved transcription factor Apontic controls the G1/S progression by inducing cyclin e during eye development

KAUST Repository

Liu, Qingxin; Wang, Xianfeng; Ikeo, Kazuho; Hirose, Susumu; Gehring, Walter Jakob; Gojobori, Takashi

2014-01-01

During Drosophila eye development, differentiation initiates in the posterior region of the eye disk and progresses anteriorly as a wave marked by the morphogenetic furrow (MF), which demarcates the boundary between anterior undifferentiated cells and posterior differentiated photoreceptors. However, the mechanism underlying the regulation of gene expression immediately before the onset of differentiation remains unclear. Here, we show that Apontic (Apt), which is an evolutionarily conserved transcription factor, is expressed in the differentiating cells posterior to the MF. Moreover, it directly induces the expression of cyclin E and is also required for the G1-to-S phase transition, which is known to be essential for the initiation of cell differentiation at the MF. These observations identify a pathway crucial for eye development, governed by a mechanism in which Cyclin E promotes the G1-to-S phase transition when regulated by Apt.

Cell-cycle regulatory proteins in human wound healing

DEFF Research Database (Denmark)

Bartkova, Jirina; Grøn, Birgitte; Dabelsteen, Erik

2003-01-01

Proper healing of mucosal wounds requires careful orchestration of epithelial cell migration and proliferation. To elucidate the molecular basis of the lack of cellular proliferation in the migrating 'epithelial tongue' during the re-epithelialization of oral mucosal wounds, the expression of cell......-cycle regulators critical for G(1)-phase progression and S-phase entry was here analysed immunohistochemically. Compared to normal human mucosa, epithelia migrating to cover 2- or 3-day-old wounds made either in vivo or in an organotypic cell culture all showed loss of the proliferation marker Ki67 and cyclins D(1......) and A, and reduced expression of cyclins D(3) and E, the cyclin D-dependent kinase 4 (CDK4), the MCM7 component of DNA replication origin complexes and the retinoblastoma protein pRb. Among the CDK inhibitors (CKIs), p16ink4a and p21Cip1 were moderately increased and decreased, respectively, whereas...

Phosphorylation of pRb by cyclin D kinase is necessary for development of cardiac hypertrophy

DEFF Research Database (Denmark)

Hinrichsen, Rebecca; Hansen, A.H.; Haunsø, S.

2008-01-01

/6-phosphorylated retinoblastoma protein (pRb) during hypertrophy and expression of an unphosphorylatable pRb mutant impaired hypertrophic growth in cardiomyocytes. Transcription factor E2F was activated by hypertrophic elicitors but activation was impaired by pharmacological inhibition of cyclin D-cdk4...

Melittin restores PTEN expression by down-regulating HDAC2 in human hepatocelluar carcinoma HepG2 cells.

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Hui Zhang

Full Text Available Melittin is a water-soluble toxic peptide derived from the venom of the bee. Although many studies show the anti-tumor activity of melittin in human cancer including glioma cells, the underlying mechanisms remain elusive. Here the effect of melittin on human hepatocelluar carcinoma HepG2 cell proliferation in vitro and further mechanisms was investigated. We found melittin could inhibit cell proliferation in vitro using Flow cytometry and MTT method. Besides, we discovered that melittin significantly downregulated the expressions of CyclinD1 and CDK4. Results of western Blot and Real-time PCR analysis indicated that melittin was capable to upregulate the expression of PTEN and attenuate histone deacetylase 2 (HDAC2 expression. Further studies demonstrated that knockdown of HDAC2 completely mimicked the effects of melittin on PTEN gene expression. Conversely, it was that the potential utility of melittin on PTEN expression was reversed in cells treated with a recombinant pEGFP-C2-HDAC2 plasmid. In addition, treatment with melittin caused a downregulation of Akt phosphorylation, while overexpression of HDAC2 promoted Akt phosphorylation. These findings suggested that the inhibitory of cell growth by melittin might be led by HDAC2-mediated PTEN upregulation, Akt inactivation, and inhibition of the PI3K/Akt signaling pathways.

Ionizing Radiation–Inducible miR-27b Suppresses Leukemia Proliferation via Targeting Cyclin A2

Energy Technology Data Exchange (ETDEWEB)

Wang, Bo; Li, Dongping; Kovalchuk, Anna; Litvinov, Dmitry; Kovalchuk, Olga, E-mail: olga.kovalchuk@uleth.ca

2014-09-01

Purpose: Ionizing radiation is a common carcinogen that is important for the development of leukemia. However, the underlying epigenetic mechanisms remain largely unknown. The goal of the study was to explore microRNAome alterations induced by ionizing radiation (IR) in murine thymus, and to determine the role of IR-inducible microRNA (miRNA/miR) in the development of leukemia. Methods and Materials: We used the well-established C57BL/6 mouse model and miRNA microarray profiling to identify miRNAs that are differentially expressed in murine thymus in response to irradiation. TIB152 human leukemia cell line was used to determine the role of estrogen receptor–α (ERα) in miR-27b transcription. The biological effects of ectopic miR-27b on leukemogenesis were measured by western immunoblotting, cell viability, apoptosis, and cell cycle analyses. Results: Here, we have shown that IR triggers the differential expression of miR-27b in murine thymus tissue in a dose-, time- and sex-dependent manner. miR-27b was significantly down-regulated in leukemia cell lines CCL119 and TIB152. Interestingly, ERα was overexpressed in those 2 cell lines, and it was inversely correlated with miR-27b expression. Therefore, we used TIB152 as a model system to determine the role of ERα in miR-27b expression and the contribution of miR-27b to leukemogenesis. β-Estradiol caused a rapid and transient reduction in miR-27b expression reversed by either ERα-neutralizing antibody or ERK1/2 inhibitor. Ectopic expression of miR-27b remarkably suppressed TIB152 cell proliferation, at least in part, by inducing S-phase arrest. In addition, it attenuated the expression of cyclin A2, although it had no effect on the levels of PCNA, PPARγ, CDK2, p21, p27, p-p53, and cleaved caspase-3. Conclusion: Our data reveal that β-estradiol/ERα signaling may contribute to the down-regulation of miR-27b in acute leukemia cell lines through the ERK1/2 pathway, and that miR-27b may function as a tumor

Ionizing Radiation–Inducible miR-27b Suppresses Leukemia Proliferation via Targeting Cyclin A2

International Nuclear Information System (INIS)

Wang, Bo; Li, Dongping; Kovalchuk, Anna; Litvinov, Dmitry; Kovalchuk, Olga

2014-01-01

Purpose: Ionizing radiation is a common carcinogen that is important for the development of leukemia. However, the underlying epigenetic mechanisms remain largely unknown. The goal of the study was to explore microRNAome alterations induced by ionizing radiation (IR) in murine thymus, and to determine the role of IR-inducible microRNA (miRNA/miR) in the development of leukemia. Methods and Materials: We used the well-established C57BL/6 mouse model and miRNA microarray profiling to identify miRNAs that are differentially expressed in murine thymus in response to irradiation. TIB152 human leukemia cell line was used to determine the role of estrogen receptor–α (ERα) in miR-27b transcription. The biological effects of ectopic miR-27b on leukemogenesis were measured by western immunoblotting, cell viability, apoptosis, and cell cycle analyses. Results: Here, we have shown that IR triggers the differential expression of miR-27b in murine thymus tissue in a dose-, time- and sex-dependent manner. miR-27b was significantly down-regulated in leukemia cell lines CCL119 and TIB152. Interestingly, ERα was overexpressed in those 2 cell lines, and it was inversely correlated with miR-27b expression. Therefore, we used TIB152 as a model system to determine the role of ERα in miR-27b expression and the contribution of miR-27b to leukemogenesis. β-Estradiol caused a rapid and transient reduction in miR-27b expression reversed by either ERα-neutralizing antibody or ERK1/2 inhibitor. Ectopic expression of miR-27b remarkably suppressed TIB152 cell proliferation, at least in part, by inducing S-phase arrest. In addition, it attenuated the expression of cyclin A2, although it had no effect on the levels of PCNA, PPARγ, CDK2, p21, p27, p-p53, and cleaved caspase-3. Conclusion: Our data reveal that β-estradiol/ERα signaling may contribute to the down-regulation of miR-27b in acute leukemia cell lines through the ERK1/2 pathway, and that miR-27b may function as a tumor

Oct-1 potentiates CREB-driven cyclin D1 promoter activation via a phospho-CREB- and CREB binding protein-independent mechanism.

Science.gov (United States)

Boulon, Séverine; Dantonel, Jean-Christophe; Binet, Virginie; Vié, Annick; Blanchard, Jean-Marie; Hipskind, Robert A; Philips, Alexandre

2002-11-01

Cyclin D1, the regulatory subunit for mid-G(1) cyclin-dependent kinases, controls the expression of numerous cell cycle genes. A cyclic AMP-responsive element (CRE), located upstream of the cyclin D1 mRNA start site, integrates mitogenic signals that target the CRE-binding factor CREB, which can recruit the transcriptional coactivator CREB-binding protein (CBP). We describe an alternative mechanism for CREB-driven cyclin D1 induction that involves the ubiquitous POU domain protein Oct-1. In the breast cancer cell line MCF-7, overexpression of Oct-1 or its POU domain strongly increases transcriptional activation of cyclin D1 and GAL4 reporter genes that is specifically dependent upon CREB but independent of Oct-1 DNA binding. Gel retardation and chromatin immunoprecipitation assays confirm that POU forms a complex with CREB bound to the cyclin D1 CRE. In solution, CREB interaction with POU requires the CREB Q2 domain and, notably, occurs with CREB that is not phosphorylated on Ser 133. Accordingly, Oct-1 also potently enhances transcriptional activation mediated by a Ser133Ala CREB mutant. Oct-1/CREB synergy is not diminished by the adenovirus E1A 12S protein, a repressor of CBP coactivator function. In contrast, E1A strongly represses CBP-enhanced transactivation by CREB phosphorylated on Ser 133. Our observation that Oct-1 potentiates CREB-dependent cyclin D1 transcriptional activity independently of Ser 133 phosphorylation and E1A-sensitive coactivator function offers a new paradigm for the regulation of cyclin D1 induction by proliferative signals.

Identification of Cyclin A Binders with a Fluorescent Peptide Sensor.

Science.gov (United States)

Pazos, Elena; Mascareñas, José L; Vázquez, M Eugenio

2016-01-01

A peptide sensor that integrates the 4-dimethylaminophthalimide (4-DMAP) fluorophore in a short cyclin A binding sequence displays a large fluorescence emission increase upon interacting with the cyclin A Binding Groove (CBG). Competitive displacement assays of this probe allow the straightforward identification of peptides that interact with the CBG, which could potentially block the recognition of CDK/cyclin A kinase substrates.

Cyclin F suppresses B-Myb activity to promote cell cycle checkpoint control

DEFF Research Database (Denmark)

Klein, Ditte Kjærsgaard; Hoffmann, Saskia; Ahlskog, Johanna K

2015-01-01

an important role in checkpoint control following ionizing radiation. Cyclin F-depleted cells initiate checkpoint signalling after ionizing radiation, but fail to maintain G2 phase arrest and progress into mitosis prematurely. Importantly, cyclin F suppresses the B-Myb-driven transcriptional programme...... that promotes accumulation of crucial mitosis-promoting proteins. Cyclin F interacts with B-Myb via the cyclin box domain. This interaction is important to suppress cyclin A-mediated phosphorylation of B-Myb, a key step in B-Myb activation. In summary, we uncover a regulatory mechanism linking the F-box protein...

Cyclin-dependent kinase inhibitor 3 is overexpressed in hepatocellular carcinoma and promotes tumor cell proliferation

International Nuclear Information System (INIS)

Xing, Chunyang; Xie, Haiyang; Zhou, Lin; Zhou, Wuhua; Zhang, Wu; Ding, Songming; Wei, Bajin; Yu, Xiaobo; Su, Rong; Zheng, Shusen

2012-01-01

Highlights: ► CDKN3 is commonly overexpressed in HCC and is associated with poor clinical outcome. ► Overexpression of CDKN3 could stimulate the proliferation of HCC cells by promoting G1/S transition. ► CDKN3 could inhibit the expression of p21 in HCC cells. ► Overexpression of CDKN3 has no effect on apoptosis and invasion of HCC cells. ► We identified 61 genes co-expressed with CDKN3, and BIRC5 was located at the center of the co-expression network. -- Abstract: Cyclin-dependent kinase inhibitor 3 (CDKN3) belongs to the protein phosphatases family and has a dual function in cell cycling. The function of this gene has been studied in several kinds of cancers, but its role in human hepatocellular carcinoma (HCC) remains to be elucidated. In this study, we found that CDKN3 was frequently overexpressed in both HCC cell lines and clinical samples, and this overexpression was correlated with poor tumor differentiation and advanced tumor stage. Functional studies showed that overexpression of CDKN3 could promote cell proliferation by stimulating G1-S transition but has no impact on cell apoptosis and invasion. Microarray-based co-expression analysis identified a total of 61 genes co-expressed with CDKN3, with most of them involved in cell proliferation, and BIRC5 was located at the center of CDKN3 co-expression network. These results suggest that CDKN3 acts as an oncogene in human hepatocellular carcinoma and antagonism of CDKN3 may be of interest for the treatment of HCC.

A conserved cyclin-binding domain determines functional interplay between anaphase-promoting complex-Cdh1 and cyclin A-Cdk2 during cell cycle progression

DEFF Research Database (Denmark)

Lukas, C; Kramer, E R; Peters, J M

2001-01-01

Periodic activity of the anaphase-promoting complex (APC) ubiquitin ligase determines progression through multiple cell cycle transitions by targeting cell cycle regulators for destruction. At the G(1)/S transition, phosphorylation-dependent dissociation of the Cdh1-activating subunit inhibits...... the APC, allowing stabilization of proteins required for subsequent cell cycle progression. Cyclin-dependent kinases (CDKs) that initiate and maintain Cdh1 phosphorylation have been identified. However, the issue of which cyclin-CDK complexes are involved has been a matter of debate, and the mechanism...... of how cyclin-CDKs interact with APC subunits remains unresolved. Here we substantiate the evidence that mammalian cyclin A-Cdk2 prevents unscheduled APC reactivation during S phase by demonstrating its periodic interaction with Cdh1 at the level of endogenous proteins. Moreover, we identified...

Differential Control of Growth, Apoptotic Activity, and Gene Expression in Human Breast Cancer Cells by Extracts Derived from Medicinal Herbs Zingiber officinale

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Ayman I. Elkady

2012-01-01

Full Text Available The present study aimed to examine the antiproliferative potentiality of an extract derived from the medicinal plant ginger (Zingiber officinale on growth of breast cancer cells. Ginger treatment suppressed the proliferation and colony formation in breast cancer cell lines, MCF-7 and MDA-MB-231. Meanwhile, it did not significantly affect viability of nontumorigenic normal mammary epithelial cell line (MCF-10A. Treatment of MCF-7 and MDA-MB-231 with ginger resulted in sequences of events marked by apoptosis, accompanied by loss of cell viability, chromatin condensation, DNA fragmentation, activation of caspase 3, and cleavage of poly(ADP-ribose polymerase. At the molecular level, the apoptotic cell death mediated by ginger could be attributed in part to upregulation of Bax and downregulation of Bcl-2 proteins. Ginger treatment downregulated expression of prosurvival genes, such as NF-κB, Bcl-X, Mcl-1, and Survivin, and cell cycle-regulating proteins, including cyclin D1 and cyclin-dependent kinase-4 (CDK-4. On the other hand, it increased expression of CDK inhibitor, p21. It also inhibited the expression of the two prominent molecular targets of cancer, c-Myc and the human telomerase reverse transcriptase (hTERT. These findings suggested that the ginger may be a promising candidate for the treatment of breast carcinomas.

Cyclin D expression in plutonium-induced lung tumors in F344 rats

Energy Technology Data Exchange (ETDEWEB)

Hahn, F.F.; Kelly, G. [SouthWest Scientific Resources, Inc., Albuquerque, NM (United States)

1995-12-01

The genetic mechanisms responsible for {alpha}-radiation-induced lung cancer in rats following inhalation of {sup 239}Pu is an ongoing area of research in our laboratory. Previous studies have examined the status of the p53 gene by immunohistochemistry. Only two tumors (2/26 squamous cell carcinomas) exhibited detectable levels of p53 products. Both were the result of mutations in codons 280 and 283. More recent studies of X-ray-induced lung tumors in rats showed a similar lack of involvement of p53. In conclusion, we found that {alpha}-radiation-induced rat lung tumors have a high incidence (31 of 39) of cyclin D{sub 1} overexpression.

Serous tubal intraepithelial carcinoma upregulates markers associated with high-grade serous carcinomas including Rsf-1 (HBXAP), cyclin E and fatty acid synthase.

Science.gov (United States)

Sehdev, Ann Smith; Kurman, Robert J; Kuhn, Elisabetta; Shih, Ie-Ming

2010-06-01

Serous tubal intraepithelial carcinoma (STIC) has been proposed as a precursor for many pelvic high-grade serous carcinomas. Our previous analysis of the ovarian cancer genome identified several genes with oncogenic potential that are amplified and/or overexpressed in the majority of high-grade serous carcinomas. Determining whether these genes are upregulated in STICs is important in further elucidating the relationship of STICs to high-grade serous carcinomas and is fundamental in understanding the molecular pathogenesis of high-grade serous carcinomas. In this study, 37 morphologically defined STICs were obtained from 23 patients with stage IIIC/IV high-grade serous carcinomas. Both STICs and the high-grade serous carcinomas were analyzed for expression of Rsf-1 (HBXAP), cyclin E, fatty acid synthase (FASN) and mucin-4. In addition, they were examined for expression of established markers including p53, Ki-67 and p16. We found that diffuse nuclear p53 and p16 immunoreactivity was observed in 27 (75%) of 36 and 18 (55%) of 33 STICs, respectively, whereas an elevated Ki-67 labeling index (>or=10%) was detected in 29 (78%) of 37 STICs. Cyclin E nuclear staining was seen in 24 (77%) of 35 STICs, whereas normal tubal epithelial cells were all negative. Increased Rsf-1 and FASN immunoreactivity occurred in 63%, and 62% of STICs, respectively, compared with adjacent normal-appearing tubal epithelium. Interestingly, only one STIC showed increased mucin-4 immunoreactivity. Carcinomas, when compared with STICs, overexpressed p16, Rsf-1, cyclin E and FASN in a higher proportion of cases. In conclusion, STICs express several markers including Rsf-1, cyclin E and FASN in high-grade serous carcinomas. In contrast, mucin-4 immunoreactivity either did not change or was reduced in most STICs. These results suggest that overexpression of Rsf-1, cyclin E and FASN occurs early in tumor progression.

p75 Neurotrophin Receptor Suppresses the Proliferation of Human Gastric Cancer Cells

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Haifeng Jin

2007-06-01

Full Text Available Identifying an effective therapeutic target is pivotal in the treatment of gastric cancer. In this study, we investigated the expression of p75 neurotrophin receptor (p75NTR in gastric cancer and the impact of its alteration on tumor growth. p75NTR expression was absent or significantly decreased in 212 cases of gastric cancers compared with the normal gastric mucosa (P < .05. Moreover, p75NTR expression was also lost or significantly decreased in various human gastric cancer cell lines. p75NTR inhibited in vitro growth activities and caused dramatic attenuation of tumor growth in animal models by induction of cell cycle arrest. Upregulation of p75NTR led to downregulation of cyclin A, cyclin D1, cyclin E, cyclin-dependent kinase 2, p-Rb, and PCNA, but to upregulation of Rb and p27 expressions. Conversely, downregulating p75NTR with specific siRNA yielded inverse results. The rescue of tumor cells from cell cycle progression by a death domain-deleted dominant-negative antagonist of p75NTR (Δp75NTR showed that the death domain transduced antiproliferative activity in a ligandindependent manner and further demonstrated the inhibitive effect of p75NTR on growth in gastric cancer. Therefore, we provided evidence that p75NTR was a potential tumor suppressor and may be used as a therapeutic target for gastric cancer.

Foci of cyclin A2 interact with actin and RhoA in mitosis.

Science.gov (United States)

Loukil, Abdelhalim; Izard, Fanny; Georgieva, Mariya; Mashayekhan, Shaereh; Blanchard, Jean-Marie; Parmeggiani, Andrea; Peter, Marion

2016-06-09

Cyclin A2 is a key player in the regulation of the cell cycle. Its degradation in mid-mitosis depends primarily on the ubiquitin-proteasome system (UPS), while autophagy also contributes. However, a fraction of cyclin A2 persists beyond metaphase. In this work, we focus on cyclin A2-rich foci detected in mitosis by high resolution imaging and analyse their movements. We demonstrate that cyclin A2 interacts with actin and RhoA during mitosis, and that cyclin A2 depletion induces a dramatic decrease in active RhoA in mitosis. Our data suggest cyclin A2 participation in RhoA activation in late mitosis.

The comparison of nuclear ubiquitous casein and cyclin-dependent kinases substrate (NUCKS) with Ki67 proliferation marker expression in common skin tumors.

Science.gov (United States)

Zduniak, Krzysztof; Agrawal, Siddarth; Symonowicz, Krzysztof; Jurczyszyn, Kamil; Ziółkowski, Piotr

2014-03-01

Nuclear ubiquitous casein and cyclin-dependent kinases substrate (NUCKS) is a chromosomal protein of unknown function. Its amino acid composition and structure of its DNA binding domain resemble those of high mobility group A (HMGA) proteins which are associated with various malignancies. Since changes in expression of HMGA are considered as a marker of tumor progression, it is possible that similar changes in expression of NUCKS could be a useful tool in diagnosis of malignant skin tumors. To investigate this assumption we used specific antibodies against NUCKS for immunohistochemistry of squamous (SCC) and basal cell carcinoma (BCC) as well as keratoacanthoma (KA). We found high expression of NUCKS in nuclei of SCC and BCC cells which exceeded expression of the well-known proliferation marker Ki67. Expression of NUCKS in benign KA was much below that of malignant tumors. With the present study and based on our previous experience we would like to suggest the NUCKS protein as a novel proliferation marker for immunohistochemical evaluation of formalin-fixed and paraffin-embedded skin tumor specimens. We would like to emphasize that NUCKS abundance in malignant skin tumors is higher than that of the well-known proliferation marker Ki67, thus allowing more precise assessment of tumor proliferation potential.

Effect of irradiation on cell cycle, cell death and expression of its related proteins in normal human oral keratinocytes

International Nuclear Information System (INIS)

Kang, Mi Ae; Heo, Min Suk; Lee, Sam Sun; Oh, Sung Ook; Choi, Soon Chul; Park, Tae Won; Lee, Sul Mi; Jeon, In Seong

2003-01-01

To investigate the radiosensitivity of the normal human oral keratinocytes (NHOK), and the effect of irradiation on cell cycle and protein expression. To evaluate the radiosensitivity of NHOK, the number of colonies and cells were counted after irradiation and the SF2 (survival fraction as 2 Gy) value, and the cell survival curve fitted on a linear-quadratic model were obtained. LDH analysis was carried out to evaluate the necrosis of NHOK at 1, 2,3, and 4 days after 2, 10, and 20 Gy irradiation. Cell cycle arrest and the induction of apoptosis were analyzed using flow cytometry at 1, 2, 3, and 4 days after 2, 10, and 20 Gy irradiation. Finally, proteins related cell cycle arrest and apoptosis were analysed by Western blot. The number of survival cell was significantly decreased in a dose-dependent manner. The cell survival curve showed SF2, α, and β values to be 0.568, 0.209, and 0.020 respectively. At 20 Gy irradiated cells showed higher optical density than the control group. After irradiation, apoptosis was not observed but G2 arrest was observed in the NHOK cells. 1 day after 10 Gy irradiation, the expression of p53 remained unchanged, the p21 WAF1/Cip1 increased and the mdm2 decreased. The expression of bax, bcl-2, cyclin B1, and cyclin D remained unchanged. These results indicate that NHOK responds to irradiation by G2 arrest, which is possibly mediated by the expression of p21 WAF1/Cip1 , and that cell necrosis occurs by high dose irradiation.

The G1/S Specific Cyclin D2 Is a Regulator of HIV-1 Restriction in Non-proliferating Cells

Science.gov (United States)

Badia, Roger; Pujantell, Maria; Riveira-Muñoz, Eva; Puig, Teresa; Torres-Torronteras, Javier; Martí, Ramón; Clotet, Bonaventura; Ampudia, Rosa M.; Ballana, Ester

2016-01-01

Macrophages are a heterogeneous cell population strongly influenced by differentiation stimuli that become susceptible to HIV-1 infection after inactivation of the restriction factor SAMHD1 by cyclin-dependent kinases (CDK). Here, we have used primary human monocyte-derived macrophages differentiated through different stimuli to evaluate macrophage heterogeneity on cell activation and proliferation and susceptibility to HIV-1 infection. Stimulation of monocytes with GM-CSF induces a non-proliferating macrophage population highly restrictive to HIV-1 infection, characterized by the upregulation of the G1/S-specific cyclin D2, known to control early steps of cell cycle progression. Knockdown of cyclin D2, enhances HIV-1 replication in GM-CSF macrophages through inactivation of SAMHD1 restriction factor by phosphorylation. Co-immunoprecipitation experiments show that cyclin D2 forms a complex with CDK4 and p21, a factor known to restrict HIV-1 replication by affecting the function of the downstream cascade that leads to SAMHD1 deactivation. Thus, we demonstrate that cyclin D2 acts as regulator of cell cycle proteins affecting SAMHD1-mediated HIV-1 restriction in non-proliferating macrophages. PMID:27541004

The Malaria Parasite Cyclin H Homolog PfCyc1 Is Required for Efficient Cytokinesis in Blood-Stage Plasmodium falciparum.

Science.gov (United States)

Robbins, Jonathan A; Absalon, Sabrina; Streva, Vincent A; Dvorin, Jeffrey D

2017-06-13

All well-studied eukaryotic cell cycles are driven by cyclins, which activate cyclin-dependent kinases (CDKs), and these protein kinase complexes are viable drug targets. The regulatory control of the Plasmodium falciparum cell division cycle remains poorly understood, and the roles of the various CDKs and cyclins remain unclear. The P. falciparum genome contains multiple CDKs, but surprisingly, it does not contain any sequence-identifiable G 1 -, S-, or M-phase cyclins. We demonstrate that P. falciparum Cyc1 (PfCyc1) complements a G 1 cyclin-depleted Saccharomyces cerevisiae strain and confirm that other identified malaria parasite cyclins do not complement this strain. PfCyc1, which has the highest sequence similarity to the conserved cyclin H, cannot complement a temperature-sensitive yeast cyclin H mutant. Coimmunoprecipitation of PfCyc1 from P. falciparum parasites identifies PfMAT1 and PfMRK as specific interaction partners and does not identify PfPK5 or other CDKs. We then generate an endogenous conditional allele of PfCyc1 in blood-stage P. falciparum using a destabilization domain (DD) approach and find that PfCyc1 is essential for blood-stage proliferation. PfCyc1 knockdown does not impede nuclear division, but it prevents proper cytokinesis. Thus, we demonstrate that PfCyc1 has a functional divergence from bioinformatic predictions, suggesting that the malaria parasite cell division cycle has evolved to use evolutionarily conserved proteins in functionally novel ways. IMPORTANCE Human infection by the eukaryotic parasite Plasmodium falciparum causes malaria. Most well-studied eukaryotic cell cycles are driven by cyclins, which activate cyclin-dependent kinases (CDKs) to promote essential cell division processes. Remarkably, there are no identifiable cyclins that are predicted to control the cell cycle in the malaria parasite genome. Thus, our knowledge regarding the basic mechanisms of the malaria parasite cell cycle remains unsatisfactory. We

FOXL2-induced follistatin attenuates activin A-stimulated cell proliferation in human granulosa cell tumors

Energy Technology Data Exchange (ETDEWEB)

Cheng, Jung-Chien; Chang, Hsun-Ming; Qiu, Xin; Fang, Lanlan; Leung, Peter C.K., E-mail: peter.leung@ubc.ca

2014-01-10

Highlights: •Activin A stimulates cell proliferation in KGN human granulosa cell tumor-derived cell line. •Cyclin D2 mediates activin A-induced KGN cell proliferation. •FOXL2 induces follistatin expression in KGN cells. •FOXL2-induced follistatin attenuates activin A-stimulated KGN cell proliferation. -- Abstract: Human granulosa cell tumors (GCTs) are rare, and their etiology remains largely unknown. Recently, the FOXL2 402C > G (C134W) mutation was found to be specifically expressed in human adult-type GCTs; however, its function in the development of human GCTs is not fully understood. Activins are members of the transforming growth factor-beta superfamily, which has been shown to stimulate normal granulosa cell proliferation; however, little is known regarding the function of activins in human GCTs. In this study, we examined the effect of activin A on cell proliferation in the human GCT-derived cell line KGN. We show that activin A treatment stimulates KGN cell proliferation. Treatment with the activin type I receptor inhibitor SB431542 blocks activin A-stimulated cell proliferation. In addition, our results show that cyclin D2 is induced by treatment with activin A and is involved in activin A-stimulated cell proliferation. Moreover, the activation of Smad signaling is required for activin A-induced cyclin D2 expression. Finally, we show that the overexpression of the wild-type FOXL2 but not the C134W mutant FOXL2 induced follistatin production. Treatment with exogenous follistatin blocks activin A-stimulated cell proliferation, and the overexpression of wild-type FOXL2 attenuates activin A-stimulated cell proliferation. These results suggest that FOXL2 may act as a tumor suppressor in human adult-type GCTs by inducing follistatin expression, which subsequently inhibits activin-stimulated cell proliferation.

The ATM and ATR inhibitors CGK733 and caffeine suppress cyclin D1 levels and inhibit cell proliferation

International Nuclear Information System (INIS)

Alao, John P; Sunnerhagen, Per

2009-01-01

The ataxia telangiectasia mutated (ATM) and the ATM- related (ATR) kinases play a central role in facilitating the resistance of cancer cells to genotoxic treatment regimens. The components of the ATM and ATR regulated signaling pathways thus provide attractive pharmacological targets, since their inhibition enhances cellular sensitivity to chemo- and radiotherapy. Caffeine as well as more specific inhibitors of ATM (KU55933) or ATM and ATR (CGK733) have recently been shown to induce cell death in drug-induced senescent tumor cells. Addition of these agents to cancer cells previously rendered senescent by exposure to genotoxins suppressed the ATM mediated p21 expression required for the survival of these cells. The precise molecular pharmacology of these agents however, is not well characterized. Herein, we report that caffeine, CGK733, and to a lesser extent KU55933, inhibit the proliferation of otherwise untreated human cancer and non-transformed mouse fibroblast cell lines. Exposure of human cancer cell lines to caffeine and CGK733 was associated with a rapid decline in cyclin D1 protein levels and a reduction in the levels of both phosphorylated and total retinoblastoma protein (RB). Our studies suggest that observations based on the effects of these compounds on cell proliferation and survival must be interpreted with caution. The differential effects of caffeine/CGK733 and KU55933 on cyclin D1 protein levels suggest that these agents will exhibit dissimilar molecular pharmacological profiles

Acquired radioresistance of cancer and the AKT/GSK3β/cyclin D1 overexpression cycle

International Nuclear Information System (INIS)

Shimura, Tsutomu

2011-01-01

Fractionated radiotherapy (RT) is widely used in cancer therapy for its advantages in the preservation of normal tissues. However, repopulation of surviving tumor cells during fractionated RT limits the efficacy of RT. In fact, repopulating tumors often acquire radioresistance and this is the major cause of failure of RT. We have recently demonstrated that human tumor cells acquire radioresistance when exposed to fractionated radiation (FR) of X-rays every 12 hours for 1 month. The acquired radioresistance was associated with overexpression of cyclin D1, a result of a series of molecular changes; constitutive activation of DNA-PK and AKT with concomitant down-regulation of glycogen synthase kinase-3β (GSK3β) which results in suppression of cyclin D1 proteolysis. Aberrant cyclin D1 overexpression in S-phase induced DNA double strand breaks which activated DNA-PK and established the vicious cycle of cycling D1 overexpression. This overexpression of cyclin D1 is responsible for the radioresistance phenotype of long-term FR cells, since this phenotype was completely abrogated by treatment of FR cells by the AKT/PKB signaling inhibitor (API-2), an AKT inhibitor or by a Cdk4 inhibitor. Thus, targeting the AKT/GSK3β/cyclin D1/Cdk4 pathway can be an efficient modality to suppress acquired radioresistance of tumor cells. In this article, I overview the newly discovered molecular mechanisms underlying acquired radioresistance of tumor cells induced by FR, and propose a strategy for eradication of tumors using fractionated RT by overcoming tumor radioresistance. (author)

Gene expression response of A253 human salivary cell line to radiation, Cis-Pt, and EGF

International Nuclear Information System (INIS)

Woloschak, G.; Paunesku, T.; Mittal, B.; Dyck, P.; Pauloski, B.; Rademaker, A.; Logemann, J.; Quigg, R.

2003-01-01

We are interested in long and short term effects of head and neck cancers treatment, and prior to the studies of patient samples, experiments were designed to observe treatment effects in cultured cells, and examine gene expression profiles from A253 human salivary cells (derived from a head and neck tumor) following exposure to gamma-rays, cisplatin (cis-Pt), and a combination of either with epidermal growth factor (EGF) treatment. A253 cells were treated by: 2 Gy or 10 Gy of γ-rays (Cs137 source, 77 cGy/min), Cis-Pt at 50 μ/mL, and EGF at 40 ng/mL. RNAs were processed and hybridized with Affymetrix Hu95A arrays according to the manufacturer's instructions. Data were scanned and analyzed and we found significant differences in the expression patterns of numerous genes were observed. Some of the more interesting genes are: Requeim [a protein required for apoptosis]; Cyclin D1 (prad1/bcl1) [a cyclin that can function as an oncogene]; FK506 Binding Protein [which may be competing with TGF-beta type I receptor for binding with FK506 thus acting against this powerful immunosuppressant]; Thioredoxin (TXN) [an oxidoreductase with multiple in vitro substrates, including ribonuclease, choriogonadotropins, coagulation factors, glucocorticoid receptor, and insulin]; Glutathione Peroxidase (GPX) [whose role in protection against oxidative stress was long ago well documented]; Aquaporin 3 (AQP3) [protein with a water-channel function that was confirmed by functional expression in Xenopus oocytes]; Eukaryotic Initiation Factor 1A (EIF1A) [a translation factor, proposed as a candidate gene for Turner syndrome]; and finally Insulin-like Growth Factor-Binding Protein 6 (IGFBP6) [an autocrine growth inhibitor shown to inhibit growth of HaCat cells and other keratinocyte cell lines

Transcriptional activation of cyclin-dependent kinase inhibitor, p21waf1 gene by treatment with a differentiation inducing agent, vesnarinone in a human salivary gland cancer cell line.

Science.gov (United States)

Omotehara, F; Nakashiro, K; Uchida, D; Hino, S; Fujimori, T; Kawamata, H

2003-03-01

Recently, a new concept for cancer therapy termed "tumor dormancy therapy" has been proposed. The concept of this therapy is to prolong the survival time of cancer patients while maintaining their quality of life. We have been developing a differentiation-inducing therapy, which is included in the tumor dormancy therapy, for salivary gland cancer. In this study, we examined the effect of a differentiation-inducing drug, Vesnarinone on the growth of several cancer cells, and examined the molecular mechanism by which Vesnarinone induces the cyclin dependent kinase inhibitor, p21waf1 in the cancer cells. Vesnarinone significantly suppressed the growth of TYS (salivary gland cancer cells), PC3 (prostate cancer cells), and A431 (squamous cell cancer cells). Furthermore, Vesnarinone dose-dependently enhanced the expression of p21waf1 mRNA in TYS cells. Using the luciferase reporter assay it was found that the enhancement of p21waf1 mRNA expression by Vesnarinone was through direct transcriptional activation of the p21waf1 promoter. Thus, analyzing the molecular mechanisms of differentiation inducing drugs may lead to the development of a new therapeutic strategy for several human malignancies, including salivary gland cancer.

The Rts1 regulatory subunit of protein phosphatase 2A is required for control of G1 cyclin transcription and nutrient modulation of cell size.

Directory of Open Access Journals (Sweden)

Karen Artiles

2009-11-01

Full Text Available The key molecular event that marks entry into the cell cycle is transcription of G1 cyclins, which bind and activate cyclin-dependent kinases. In yeast cells, initiation of G1 cyclin transcription is linked to achievement of a critical cell size, which contributes to cell-size homeostasis. The critical cell size is modulated by nutrients, such that cells growing in poor nutrients are smaller than cells growing in rich nutrients. Nutrient modulation of cell size does not work through known critical regulators of G1 cyclin transcription and is therefore thought to work through a distinct pathway. Here, we report that Rts1, a highly conserved regulatory subunit of protein phosphatase 2A (PP2A, is required for normal control of G1 cyclin transcription. Loss of Rts1 caused delayed initiation of bud growth and delayed and reduced accumulation of G1 cyclins. Expression of the G1 cyclin CLN2 from an inducible promoter rescued the delayed bud growth in rts1Delta cells, indicating that Rts1 acts at the level of transcription. Moreover, loss of Rts1 caused altered regulation of Swi6, a key component of the SBF transcription factor that controls G1 cyclin transcription. Epistasis analysis revealed that Rts1 does not work solely through several known critical upstream regulators of G1 cyclin transcription. Cells lacking Rts1 failed to undergo nutrient modulation of cell size. Together, these observations demonstrate that Rts1 is a key player in pathways that link nutrient availability, cell size, and G1 cyclin transcription. Since Rts1 is highly conserved, it may function in similar pathways in vertebrates.

Localization of two mammalian cyclin dependent kinases during mammalian meiosis

NARCIS (Netherlands)

Ashley, T.; Walpita, D.; de rooij, D. G.

2001-01-01

Mammalian meiotic progression, like mitotic cell cycle progression, is regulated by cyclins and cyclin dependent kinases (CDKs). However, the unique requirements of meiosis (homologous synapsis, reciprocal recombination and the dual divisions that segregate first homologues, then sister chromatids)

Cyclin D3 interacts with vitamin D receptor and regulates its transcription activity

International Nuclear Information System (INIS)

Jian Yongzhi; Yan Jun; Wang Hanzhou; Chen Chen; Sun Maoyun; Jiang Jianhai; Lu Jieqiong; Yang Yanzhong; Gu Jianxin

2005-01-01

D-type cyclins are essential for the progression through the G1 phase of the cell cycle. Besides serving as cell cycle regulators, D-type cyclins were recently reported to have transcription regulation functions. Here, we report that cyclin D3 is a new interacting partner of vitamin D receptor (VDR), a member of the superfamily of nuclear receptors for steroid hormones, thyroid hormone, and the fat-soluble vitamins A and D. The interaction was confirmed with methods of yeast two-hybrid system, in vitro binding analysis and in vivo co-immunoprecipitation. Cyclin D3 interacted with VDR in a ligand-independent manner, but treatment of the ligand, 1,25-dihydroxyvitamin D3, strengthened the interaction. Confocal microscopy analysis showed that ligand-activated VDR led to an accumulation of cyclin D3 in the nuclear region. Cyclin D3 up-regulated transcriptional activity of VDR and this effect was counteracted by overexpression of CDK4 and CDK6. These findings provide us a new clue to understand the transcription regulation functions of D-type cyclins

Selective anticancer activity of a hexapeptide with sequence homology to a non-kinase domain of Cyclin Dependent Kinase 4

Directory of Open Access Journals (Sweden)

Agarwala Usha

2011-06-01

Full Text Available Abstract Background Cyclin-dependent kinases 2, 4 and 6 (Cdk2, Cdk4, Cdk6 are closely structurally homologous proteins which are classically understood to control the transition from the G1 to the S-phases of the cell cycle by combining with their appropriate cyclin D or cyclin E partners to form kinase-active holoenzymes. Deregulation of Cdk4 is widespread in human cancer, CDK4 gene knockout is highly protective against chemical and oncogene-mediated epithelial carcinogenesis, despite the continued presence of CDK2 and CDK6; and overexpresssion of Cdk4 promotes skin carcinogenesis. Surprisingly, however, Cdk4 kinase inhibitors have not yet fulfilled their expectation as 'blockbuster' anticancer agents. Resistance to inhibition of Cdk4 kinase in some cases could potentially be due to a non-kinase activity, as recently reported with epidermal growth factor receptor. Results A search for a potential functional site of non-kinase activity present in Cdk4 but not Cdk2 or Cdk6 revealed a previously-unidentified loop on the outside of the C'-terminal non-kinase domain of Cdk4, containing a central amino-acid sequence, Pro-Arg-Gly-Pro-Arg-Pro (PRGPRP. An isolated hexapeptide with this sequence and its cyclic amphiphilic congeners are selectively lethal at high doses to a wide range of human cancer cell lines whilst sparing normal diploid keratinocytes and fibroblasts. Treated cancer cells do not exhibit the wide variability of dose response typically seen with other anticancer agents. Cancer cell killing by PRGPRP, in a cyclic amphiphilic cassette, requires cells to be in cycle but does not perturb cell cycle distribution and is accompanied by altered relative Cdk4/Cdk1 expression and selective decrease in ATP levels. Morphological features of apoptosis are absent and cancer cell death does not appear to involve autophagy. Conclusion These findings suggest a potential new paradigm for the development of broad-spectrum cancer specific therapeutics with

Differential control of growth, apoptotic activity and gene expression in human colon cancer cells by extracts derived from medicinal herbs, Rhazya stricta and Zingiber officinale and their combination.

Science.gov (United States)

Elkady, Ayman I; Hussein, Rania Abd El Hamid; Abu-Zinadah, Osama A

2014-11-07

To investigate the effects of extracts from Rhazya stricta (R. stricta) and Zingiber officinale (Z. officinale) on human colorectal cancer cells. Human colorectal cancer cells (HCT116) were subjected to increasing doses of crude alkaloid extracts from R. stricta (CAERS) and crude flavonoid extracts from Z. officinale (CFEZO). Cells were then harvested after 24, 48 or 72 h and cell viability was examined by trypan blue exclusion dye test; clonogenicity and soft agar colony-forming assays were also carried out. Nuclear stain (Hoechst 33342), acridine orange/ethidium bromide double staining, agarose gel electrophoresis and comet assays were performed to assess pro-apoptotic potentiality of the extracts. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR), using gene-specific primers and Western blot analyses were performed to assess the impact of CAERS and CFEZO on the expression levels of key regulatory proteins in HCT116 cells. Treatment with a combination of CAERS and CFEZO synergistically suppressed the proliferation, colony formation and anchorage-independent growth of HCT116 cells. Calculated IC50, after 24, 48 and 72 h, were 70, 90 and 130 μg/mL for CAERS, 65, 85 and 120 μg/mL for CFEZO and 20, 25 and 45 μg/mL for both agents, respectively. CAERS- and CFEZO-treated cells exhibited morphologic and biochemical features of apoptotic cell death. The induction of apoptosis was associated with the release of mitochondrial cytochrome c, an increase in the Bax/Bcl-2 ratio, activation of caspases 3 and 9 and cleavage of poly ADP-ribose polymerase. CAERS and CFEZO treatments downregulated expression levels of anti-apoptotic proteins including Bcl-2, Bcl-X, Mcl-1, survivin and XIAP, and upregulated expression levels of proapoptotic proteins such as Bad and Noxa. CAERS and CFEZO treatments elevated expression levels of the oncosuppressor proteins, p53, p21 and p27, and reduced levels of the oncoproteins, cyclin D1, cyclin/cyclin-dependent kinase-4 and

miR-338-3p Is Down-Regulated by Hepatitis B Virus X and Inhibits Cell Proliferation by Targeting the 3′-UTR Region of CyclinD1

Directory of Open Access Journals (Sweden)

Xiaoyu Fu

2012-07-01

Full Text Available Hepatitis B virus X protein (HBx is recognized as an oncogene in hepatocellular carcinoma (HCC. HBx regulates microRNA expression, including down-regulating miR-338-3p in LO2 cells. Here, we investigated miR-338-3p function in HBx-mediated hepatocarcinogenesis. In 23 HBV-infected HCC clinical patient tumor and adjacent non-tumor control tissues, 17 and 19 tumors expressed HBx mRNA and protein, respectively. When considered as a group, HBV-infected HCC tumors had lower miR-338-3p expression than controls; however, miR-338-3p was only significantly down-regulated in HBx-positive tumors, indicating that HBx inversely correlated with miR-338-3p. Functional characterization of miR-338-3p indicated that miR-338-3p mimics inhibited cell proliferation by inducing cell cycle arrest at the G1/S phase as assessed by EdU and cell cycle assays in HBx-expressing LO2 cells. CyclinD1, containing two putative miR-338-3p targets, was confirmed as a direct target using 3′-UTR luciferase reporter assays from cells transfected with mutated binding sites. Mutating the 2397–2403 nt binding site conferred the greatest resistance to miR-338-3p suppression of CyclinD1, indicating that miR-338-3p suppresses CyclinD1 at this site. Overall, this study demonstrates that miR-338-3p inhibits proliferation by regulating CyclinD1, and HBx down-regulates miR-338-3p in HCC. This newly identified miR-338-3p/CyclinD1 interaction provides novel insights into HBx-mediated hepatocarcinogenesis and may facilitate therapeutic development against HCC.

Deciphering the binding behavior of flavonoids to the cyclin dependent kinase 6/cyclin D complex.

Directory of Open Access Journals (Sweden)

Jingxiao Zhang

Full Text Available Flavonoids, a class of natural compounds with variable phenolic structures, have been found to possess anti-cancer activities by modulating different enzymes and receptors like CDK6. To understand the binding behavior of flavonoids that inhibit the active CDK6, molecular dynamics (MD simulations were performed on six inhibitors, chrysin (M01, fisetin (M03, galangin (M04, genistein (M05, quercetin (M06 and kaempferol (M07, complexed with CDK6/cyclin D. For all six flavonoids, the 3'-OH and 4'-OH of B-ring were found to be favorable for hydrogen bond formation, but the 3-OH on the C-ring and 5-OH on the A-ring were unfavorable, which were confirmed by the MD simulation results of the test molecule, 3', 4', 7-trihydroxyflavone (M15. The binding efficiencies of flavonoids against the CDK6/cyclin D complex were mainly through the electrostatic (especially the H-bond force and vdW interactions with residues ILE19, VAL27, ALA41, GLU61, PHE98, GLN103, ASP163 and LEU152. The order of binding affinities of these flavonoids toward the CDK6/cyclin D was M03 > M01 > M07 > M15 > M06 > M05 > M04. It is anticipated that the binding features of flavonoid inhibitors studied in the present work may provide valuable insights for the development of CDK6 inhibitors.

Cell type-specific translational repression of Cyclin B during meiosis in males.

Science.gov (United States)

Baker, Catherine Craig; Gim, Byung Soo; Fuller, Margaret T

2015-10-01

The unique cell cycle dynamics of meiosis are controlled by layers of regulation imposed on core mitotic cell cycle machinery components by the program of germ cell development. Although the mechanisms that regulate Cdk1/Cyclin B activity in meiosis in oocytes have been well studied, little is known about the trans-acting factors responsible for developmental control of these factors in male gametogenesis. During meiotic prophase in Drosophila males, transcript for the core cell cycle protein Cyclin B1 (CycB) is expressed in spermatocytes, but the protein does not accumulate in spermatocytes until just before the meiotic divisions. Here, we show that two interacting proteins, Rbp4 and Fest, expressed at the onset of spermatocyte differentiation under control of the developmental program of male gametogenesis, function to direct cell type- and stage-specific repression of translation of the core G2/M cell cycle component cycB during the specialized cell cycle of male meiosis. Binding of Fest to Rbp4 requires a 31-amino acid region within Rbp4. Rbp4 and Fest are required for translational repression of cycB in immature spermatocytes, with Rbp4 binding sequences in a cell type-specific shortened form of the cycB 3' UTR. Finally, we show that Fest is required for proper execution of meiosis I. © 2015. Published by The Company of Biologists Ltd.

Disrupted G1 to S phase clearance via cyclin signaling impairs liver tissue repair in thioacetamide-treated type 1 diabetic rats

International Nuclear Information System (INIS)

Devi, Sachin S.; Mehendale, Harihara M.

2005-01-01

Previously we reported that a nonlethal dose of thioacetamide (TA, 300 mg/kg) causes 90% mortality in type 1 diabetic (DB) rats because of irreversible acute liver injury owing to inhibited hepatic tissue repair, primarily due to blockage of G 0 to S phase progression of cell division cycle. On the other hand, DB rats receiving 30 mg TA/kg exhibited equal initial liver injury and delayed tissue repair compared to nondiabetic (NDB) rats receiving 300 mg TA/kg, resulting in a delay in recovery from liver injury and survival. The objective of the present study was to test the hypothesis that impaired cyclin-regulated progression of G 1 to S phase of the cell cycle may explain inhibited liver tissue repair, hepatic failure, and death, contrasted with delayed liver tissue repair but survival observed in the DB rats receiving 300 in contrast to 30 mg TA/kg. In the TA-treated NDB rats sustained MAPKs and cyclin expression resulted in higher phosphorylation of retinoblastoma (pRb), explaining prompt tissue repair and survival. In contrast, DB rats receiving the same dose of TA (300 mg/kg) exhibited suppressed MAPKs and cyclin expression that led to inhibition of pRb, inhibited tissue repair, and death. On the other hand, DB rats receiving 30 mg TA/kg exhibited delayed up regulation of MAPK signaling that delayed the expression of CD1 and pRb, explaining delayed stimulation of tissue repair observed in this group. In conclusion, the hepatotoxicant TA has a dose-dependent adverse effect on cyclin-regulated pRb signaling: the lower dose causes a recoverable delay, whereas the higher dose inhibits it with corresponding effect on the ultimate outcomes on hepatic tissue repair; this dose-dependent adverse effect is substantially shifted to the left of the dose response curve in diabetes

Resveratrol Suppresses Growth and Migration of Myelodysplastic Cells by Inhibiting the Expression of Elevated Cyclin D1 (CCND1).

Science.gov (United States)

Zhou, Wei; Xu, Shilin; Ying, Yi; Zhou, Ruiqing; Chen, Xiaowei

2017-11-01

Myelodysplastic syndromes (MDS) are a group of heterogeneous diseases characterized by poorly formed blood cells. We wanted to elucidate the underlying molecular mechanism to better determine pathogenesis, prognosis, diagnosis, and treatment for patients with MDS. We compared gene expression levels between normal and MDS tissue samples by immunohistochemical analysis. We studied the proliferation, survival, and migration of MDS cells using the EDU assay, colony formation, and transwell assays. We assessed the apoptotic rate and cell cycle status using flow cytometry and Hoechst staining. Finally, we evaluated RNA and protein expressions using polymerase chain reaction and Western blots, respectively. We found that resveratrol suppressed SKM-1 (an advanced MDS cell line) proliferation in a dose-dependent manner. Consistent with this finding, the EDU and colony formation assays also showed that resveratrol inhibited SKM-1 growth. Moreover, flow cytometry and Hoechst 33258 staining demonstrated that resveratrol induced apoptosis and a change in cell cycle status in SKM-1 cells, while the transwell assay showed that resveratrol reduced the migratory ability of SKM-1 cells. Resveratrol also decreased the expression of CCND1 (a gene that encodes the cyclin D1 protein) and increased expressions of KMT2A [lysine (K)-specific methyltransferase 2A] and caspase-3, suggesting that resveratrol exerts its effect by regulating CCND1 in SKM-1 cells. In addition, a combination of resveratrol and the PI3K/AKT inhibitor LY294002 exhibited a stronger inhibitory effect on the SKM-1 cells, compared with resveratrol alone. Our study proved that resveratrol suppresses SKM-1 growth and migration by inhibiting CCND1 expression. This finding provides novel insights into the pathogenesis of MDS and might help develop new diagnosis and treatment for patients with MDS.

Ran GTPase protein promotes human pancreatic cancer proliferation by deregulating the expression of Survivin and cell cycle proteins

International Nuclear Information System (INIS)

Deng, Lin; Lu, Yuanyuan; Zhao, Xiaodi; Sun, Yi; Shi, Yongquan; Fan, Hongwei; Liu, Changhao; Zhou, Jinfeng; Nie, Yongzhan; Wu, Kaichun; Fan, Daiming; Guo, Xuegang

2013-01-01

Highlights: •Overexpression of Ran in pancreatic cancer was correlated with histological grade. •Downregulation of Ran could induce cell apoptosis and inhibit cell proliferation. •The effects were mediated by cell cycle proteins, Survivin and cleaved Caspase-3. -- Abstract: Ran, a member of the Ras GTPase family, has important roles in nucleocytoplasmic transport. Herein, we detected Ran expression in pancreatic cancer and explored its potential role on tumour progression. Overexpressed Ran in pancreatic cancer tissues was found highly correlated with the histological grade. Downregulation of Ran led to significant suppression of cell proliferation, cell cycle arrest at the G1/S phase and induction of apoptosis. In vivo studies also validated that result. Further studies revealed that those effects were at least partly mediated by the downregulation of Cyclin A, Cyclin D1, Cyclin E, CDK2, CDK4, phospho-Rb and Survivin proteins and up regulation of cleaved Caspase-3

Signal transducer and activator of transcription 5 activation is sufficient to drive transcriptional induction of cyclin D2 gene and proliferation of rat pancreatic beta-cells

DEFF Research Database (Denmark)

Friedrichsen, Birgitte N; Richter, Henrijette E; Hansen, Johnny A

2003-01-01

in a time-dependent manner by hGH in INS-1 cells. Inhibition of protein synthesis by coincubation with cycloheximide did not affect the hGH-induced increase of cyclin D2 mRNA levels at 4 h. Expression of a dominant negative STAT5 mutant, STAT5aDelta749, partially inhibited cyclin D2 protein levels. INS-1...... cells transiently transfected with a cyclin D2 promoter-reporter construct revealed a 3- to 5-fold increase of transcriptional activity in response to hGH stimulation. Furthermore, coexpression of a constitutive active STAT5 mutant (either CA-STAT5a or CA-STAT5b) was sufficient to drive transactivation...

Regulation of sonic hedgehog-GLI1 downstream target genes PTCH1, Cyclin D2, Plakoglobin, PAX6 and NKX2.2 and their epigenetic status in medulloblastoma and astrocytoma

International Nuclear Information System (INIS)

Shahi, Mehdi H; Afzal, Mohammad; Sinha, Subrata; Eberhart, Charles G; Rey, Juan A; Fan, Xing; Castresana, Javier S

2010-01-01

The Sonic hedgehog (Shh) signaling pathway is critical for cell growth and differentiation. Impairment of this pathway can result in both birth defects and cancer. Despite its importance in cancer development, the Shh pathway has not been thoroughly investigated in tumorigenesis of brain tumors. In this study, we sought to understand the regulatory roles of GLI1, the immediate downstream activator of the Shh signaling pathway on its downstream target genes PTCH1, Cyclin D2, Plakoglobin, NKX2.2 and PAX6 in medulloblastoma and astrocytic tumors. We silenced GLI1 expression in medulloblastoma and astrocytic cell lines by transfection of siRNA against GLI1. Subsequently, we performed RT-PCR and quantitative real time RT-PCR (qRT-PCR) to assay the expression of downstream target genes PTCH1, Cyclin D2, Plakoglobin, NKX2.2 and PAX6. We also attempted to correlate the pattern of expression of GLI1 and its regulated genes in 14 cell lines and 41 primary medulloblastoma and astrocytoma tumor samples. We also assessed the methylation status of the Cyclin D2 and PTCH1 promoters in these 14 cell lines and 58 primary tumor samples. Silencing expression of GLI1 resulted up-regulation of all target genes in the medulloblastoma cell line, while only PTCH1 was up-regulated in astrocytoma. We also observed methylation of the cyclin D2 promoter in a significant number of astrocytoma cell lines (63%) and primary astrocytoma tumor samples (32%), but not at all in any medulloblastoma samples. PTCH1 promoter methylation was less frequently observed than Cyclin D2 promoter methylation in astrocytomas, and not at all in medulloblastomas. Our results demonstrate different regulatory mechanisms of Shh-GLI1 signaling. These differences vary according to the downstream target gene affected, the origin of the tissue, as well as epigenetic regulation of some of these genes

Rational design of a cyclin A fluorescent peptide sensor.

Science.gov (United States)

Pazos, Elena; Pérez, Miguel; Gutiérrez-de-Terán, Hugo; Orzáez, Mar; Guevara, Tatiana; Mascareñas, José L; Vázquez, M Eugenio

2011-10-26

We report the design and development of a fluorescent sensor specifically designed to target cyclin A, a protein that plays a key role in the regulation of the cell cycle. Computational studies provide a molecular picture that explains the observed emission increase, suggesting that the 4-DMAP fluorophore in the peptide is protected from the bulk solvent when inserted into the hydrophobic binding groove of cyclin A.

The prognostic implication of the expression of EGFR, p53, cyclin D1, Bcl-2 and p16 in primary locally advanced oral squamous cell carcinoma cases: a tissue microarray study.

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Solomon, Monica Charlotte; Vidyasagar, M S; Fernandes, Donald; Guddattu, Vasudev; Mathew, Mary; Shergill, Ankur Kaur; Carnelio, Sunitha; Chandrashekar, Chetana

2016-12-01

Oral squamous cell carcinomas comprise a heterogeneous tumor cell population with varied molecular characteristics, which makes prognostication of these tumors a complex and challenging issue. Thus, molecular profiling of these tumors is advantageous for an accurate prognostication and treatment planning. This is a retrospective study on a cohort of primary locally advanced oral squamous cell carcinomas (n = 178) of an Indian rural population. The expression of EGFR, p53, cyclin D1, Bcl-2 and p16 in a cohort of primary locally advanced oral squamous cell carcinomas was evaluated. A potential biomarker that can predict the tumor response to treatment was identified. Formalin-fixed paraffin-embedded tumor blocks of (n = 178) of histopathologically diagnosed cases of locally advanced oral squamous cell carcinomas were selected. Tissue microarray blocks were constructed with 2 cores of 2 mm diameter from each tumor block. Four-micron-thick sections were cut from these tissue microarray blocks. These tissue microarray sections were immunohistochemically stained for EGFR, p53, Bcl-2, cyclin D1 and p16. In this cohort, EGFR was the most frequently expressed 150/178 (84%) biomarker of the cases. Kaplan-Meier analysis showed a significant association (p = 0.038) between expression of p53 and a poor prognosis. A Poisson regression analysis showed that tumors that expressed p53 had a two times greater chance of recurrence (unadjusted IRR-95% CI 2.08 (1.03, 4.5), adjusted IRR-2.29 (1.08, 4.8) compared with the tumors that did not express this biomarker. Molecular profiling of oral squamous cell carcinomas will enable us to categorize our patients into more realistic risk groups. With biologically guided tumor characterization, personalized treatment protocols can be designed for individual patients, which will improve the quality of life of these patients.

Differentiation-inducing factor-1 induces cyclin D1 degradation through the phosphorylation of Thr286 in squamous cell carcinoma

International Nuclear Information System (INIS)

Mori, Jun; Takahashi-Yanaga, Fumi; Miwa, Yoshikazu; Watanabe, Yutaka; Hirata, Masato; Morimoto, Sachio; Shirasuna, Kanemitsu; Sasaguri, Toshiyuki

2005-01-01

Differentiation-inducing factors (DIFs) are morphogens which induce cell differentiation in Dictyostelium. We reported that DIF-1 and DIF-3 inhibit proliferation and induce differentiation in mammalian cells. In this study, we investigated the effect of DIF-1 on oral squamous cell carcinoma cell lines NA and SAS, well differentiated and poorly differentiated cell lines, respectively. Although DIF-1 did not induce the expression of cell differentiation makers in these cell lines, it inhibited the proliferation of NA and SAS in a dose-dependent manner by restricting the cell cycle in the G 0 /G 1 phase. DIF-1 induced cyclin D1 degradation, but this effect was prevented by treatment with lithium chloride and SB216763, the inhibitors of glycogen synthase kinase-3β (GSK-3β). Depletion of endogenous GSK-3β by RNA interference also attenuated the effect of DIF-1 on cyclin D1 degradation. Therefore, we investigated the effect of DIF-1 on GSK-3β and found that DIF-1 dephosphorylated GSK-3β on Ser 9 and induced the nuclear translocation of GSK-3β, suggesting that DIF-1 activated GSK-3β. Then, we examined the effect of DIF-1 on cyclin D1 mutants (Thr286Ala, Thr288Ala, and Thr286/288Ala). We revealed that Thr286Ala and Thr286/288Ala mutants were highly resistant to DIF-1-induced degradation compared with wild-type cyclin D1, indicating that the phosphorylation of Thr 286 was critical for cyclin D1 degradation induced by DIF-1. These results suggest that DIF-1 induces degradation of cyclin D1 through the GSK-3β-mediated phosphorylation of Thr 286

The Drosophila PNG kinase complex regulates the translation of cyclin B.

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Vardy, Leah; Orr-Weaver, Terry L

2007-01-01

The Drosophila PAN GU (PNG) kinase complex regulates the developmental translation of cyclin B. cyclin B mRNA becomes unmasked during oogenesis independent of PNG activity, but PNG is required for translation from egg activation. We find that although polyadenylation of cyclin B augments translation, it is not essential, and a fully elongated poly(A) is not required for translation to proceed. In fact, changes in poly(A) tail length are not sufficient to account for PNG-mediated control of cyclin B translation and of the early embryonic cell cycles. We present evidence that PNG functions instead as an antagonist of PUMILIO-dependent translational repression. Our data argue that changes in poly(A) tail length are not a universal mechanism governing embryonic cell cycles, and that PNG-mediated derepression of translation is an important alternative mechanism in Drosophila.

Lebein, a snake venom disintegrin, suppresses human colon cancer cells proliferation and tumor-induced angiogenesis through cell cycle arrest, apoptosis induction and inhibition of VEGF expression.

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Zakraoui, Ons; Marcinkiewicz, Cezary; Aloui, Zohra; Othman, Houcemeddine; Grépin, Renaud; Haoues, Meriam; Essafi, Makram; Srairi-Abid, Najet; Gasmi, Ammar; Karoui, Habib; Pagès, Gilles; Essafi-Benkhadir, Khadija

2017-01-01

Lebein, is an heterodimeric disintegrin isolated from Macrovipera lebetina snake venom that was previously characterized as an inhibitor of ADP-induced platelet aggregation. In this study, we investigated the effect of Lebein on the p53-dependent growth of human colon adenocarcinoma cell lines. We found that Lebein significantly inhibited LS174 (p53wt), HCT116 (p53wt), and HT29 (p53mut) colon cancer cell viability by inducing cell cycle arrest through the modulation of expression levels of the tumor suppression factor p53, cell cycle regulating proteins cyclin D1, CDK2, CDK4, retinoblastoma (Rb), CDK1, and cyclin-dependent kinase inhibitors p21 and p27. Interestingly, Lebein-induced apoptosis of colon cancer cells was dependent on their p53 status. Thus, in LS174 cells, cell death was associated with PARP cleavage and the activation of caspases 3 and 8 while in HCT116 cells, Lebein induced caspase-independent apoptosis through increased expression of apoptosis inducing factor (AIF). In LS174 cells, Lebein triggers the activation of the MAPK ERK1/2 pathway through induction of reactive oxygen species (ROS). It also decreased cell adhesion and migration to fibronectin through down regulation of α5β1 integrin. Moreover, Lebein significantly reduced the expression of two angiogenesis stimulators, Vascular Endothelial Growth Factor (VEGF) and Neuropilin 1 (NRP1). It inhibited the VEGF-induced neovascularization process in the quail embryonic CAM system and blocked the development of human colon adenocarcinoma in nude mice. Overall, our work indicates that Lebein may be useful to design a new therapy against colon cancer. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Impact of 9p deletion and p16, Cyclin D1, and Myc hyperexpression on the outcome of anaplastic oligodendrogliomas.

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Karine Michaud

Full Text Available To study the presence of 9p deletion and p16, cyclin D1 and Myc expression and their respective diagnostic and prognostic interest in oligodendrogliomas.We analyzed a retrospective series of 40 consecutive anaplastic oligodendrogliomas (OIII from a single institution and compared them to a control series of 10 low grade oligodendrogliomas (OII. Automated FISH analysis of chromosome 9p status and immunohistochemistry for p16, cyclin D1 and Myc was performed for all cases and correlated with clinical and histological data, event free survival (EFS and overall survival (OS.Chromosome 9p deletion was observed in 55% of OIII (22/40 but not in OII. Deletion was highly correlated to EFS (median = 29 versus 53 months, p<0.0001 and OS (median = 48 versus 83 months, p<0.0001 in both the total cohort and the OIII population. In 9p non-deleted oligodendrogliomas, p16 hyperexpression correlated with a shorter OS (p = 0.02 in OII and p = 0.0001 in OIII whereas lack of p16 expression was correlated to a shorter EFS and OS in 9p deleted OIII (p = 0.001 and p = 0.0002 respectively. Expression of Cyclin D1 was significantly higher in OIII (median expression 45% versus 14% for OII, p = 0.0006 and was correlated with MIB-1 expression (p<0.0001, vascular proliferation (p = 0.002, tumor necrosis (p = 0.04 and a shorter EFS in the total cohort (p = 0.05. Hyperexpression of Myc was correlated to grade (median expression 27% in OII versus 35% in OIII, p = 0.03, and to a shorter EFS in 9p non-deleted OIII (p = 0.01.Chromosome 9p deletion identifies a subset of OIII with significantly worse prognosis. The combination of 9p status and p16 expression level identifies two distinct OIII populations with divergent prognosis. Hyperexpression of Bcl1 and Myc appears highly linked to anaplasia but the prognostic value is unclear and should be investigated further.

Structural and functional analysis of cyclin D1 reveals p27 and substrate inhibitor binding requirements.

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Liu, Shu; Bolger, Joshua K; Kirkland, Lindsay O; Premnath, Padmavathy N; McInnes, Campbell

2010-12-17

An alternative strategy for inhibition of the cyclin dependent kinases (CDKs) in antitumor drug discovery is afforded through the substrate recruitment site on the cyclin positive regulatory subunit. Critical CDK substrates such as the Rb and E2F families must undergo cyclin groove binding before phosphorylation, and hence inhibitors of this interaction also block substrate specific kinase activity. This approach offers the potential to generate highly selective and cell cycle specific CDK inhibitors and to reduce the inhibition of transcription mediated through CDK7 and 9, commonly observed with ATP competitive compounds. While highly potent peptide and small molecule inhibitors of CDK2/cyclin A, E substrate recruitment have been reported, little information has been generated on the determinants of inhibitor binding to the cyclin groove of the CDK4/cyclin D1 complex. CDK4/cyclin D is a validated anticancer drug target and continues to be widely pursued in the development of new therapeutics based on cell cycle blockade. We have therefore investigated the structural basis for peptide binding to its cyclin groove and have examined the features contributing to potency and selectivity of inhibitors. Peptidic inhibitors of CDK4/cyclin D of pRb phosphorylation have been synthesized, and their complexes with CDK4/cyclin D1 crystal structures have been generated. Based on available structural information, comparisons of the cyclin grooves of cyclin A2 and D1 are presented and provide insights into the determinants for peptide binding and the basis for differential binding and inhibition. In addition, a complex structure has been generated in order to model the interactions of the CDKI, p27(KIP)¹, with cyclin D1. This information has been used to shed light onto the endogenous inhibition of CDK4 and also to identify unique aspects of cyclin D1 that can be exploited in the design of cyclin groove based CDK inhibitors. Peptidic and nonpeptidic compounds have been

A cyclin-dependent kinase inhibitor, dinaciclib in preclinical treatment models of thyroid cancer.

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Shu-Fu Lin

Full Text Available We explored the therapeutic effects of dinaciclib, a cyclin-dependent kinase (CDK inhibitor, in the treatment of thyroid cancer.Seven cell lines originating from three pathologic types of thyroid cancer (papillary, follicular and anaplastic were studied. The cytotoxicity of dinaciclib was measured using a lactate dehydrogenase assay. The expression of proteins associated with cell cycle and apoptosis was assessed using Western blot analysis and immunofluorescence microscopy. Cell cycle distribution was measured by flow cytometry and immunofluorescence microscopy. Apoptosis and caspase-3 activity were measured by flow cytometry and fluorometric assay. Mice bearing flank anaplastic thyroid cancer (ATC were treated with intraperitoneal injections of dinaciclib.Dinaciclib inhibited thyroid cancer cell proliferation in a dose-dependent manner. Dinaciclib had a low median-effect dose (≤ 16.0 nM to inhibit cell proliferation in seven thyroid cancer cell lines. Dinaciclib decreased CDK1, cyclin B1, and Aurora A expression, induced cell cycle arrest in the G2/M phase, and induced accumulation of prophase mitotic cells. Dinaciclib decreased Mcl-1, Bcl-xL and survivin expression, activated caspase-3 and induced apoptosis. In vivo, the growth of ATC xenograft tumors was retarded in a dose-dependent fashion with daily dinaciclib treatment. Higher-dose dinaciclib (50 mg/kg caused slight, but significant weight loss, which was absent with lower-dose dinaciclib (40 mg/kg treatment.Dinaciclib inhibited thyroid cancer proliferation both in vitro and in vivo. These findings support dinaciclib as a potential drug for further studies in clinical trials for the treatment of patients with refractory thyroid cancer.

MicroRNA-193b represses cell proliferation and regulates cyclin D1 in melanoma.

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Chen, Jiamin; Feilotter, Harriet E; Paré, Geneviève C; Zhang, Xiao; Pemberton, Joshua G W; Garady, Cherif; Lai, Dulcie; Yang, Xiaolong; Tron, Victor A

2010-05-01

Cutaneous melanoma is an aggressive form of human skin cancer characterized by high metastatic potential and poor prognosis. To better understand the role of microRNAs (miRNAs) in melanoma, the expression of 470 miRNAs was profiled in tissue samples from benign nevi and metastatic melanomas. We identified 31 miRNAs that were differentially expressed (13 up-regulated and 18 down-regulated) in metastatic melanomas relative to benign nevi. Notably, miR-193b was significantly down-regulated in the melanoma tissues examined. To understand the role of miR-193b in melanoma, functional studies were undertaken. Overexpression of miR-193b in melanoma cell lines repressed cell proliferation. Gene expression profiling identified 314 genes down-regulated by overexpression of miR-193b in Malme-3M cells. Eighteen of these down-regulated genes, including cyclin D1 (CCND1), were also identified as putative miR-193b targets by TargetScan. Overexpression of miR-193b in Malme-3M cells down-regulated CCND1 mRNA and protein by > or = 50%. A luciferase reporter assay confirmed that miR-193b directly regulates CCND1 by binding to the 3'untranslated region of CCND1 mRNA. These studies indicate that miR-193b represses cell proliferation and regulates CCND1 expression and suggest that dysregulation of miR-193b may play an important role in melanoma development.

Perinatal exposure to BDE-99 causes decreased protein levels of cyclin D1 via GSK3β activation and increased ROS production in rat pup livers.

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Blanco, Jordi; Mulero, Miquel; Domingo, Jose L; Sanchez, Domènec J

2014-02-01

We here examined the potential liver toxicity in rat pups from dams exposed during the gestational and lactation periods to 2,2',4,4',5-pentabromodiphenyl ether (BDE-99). Dams were exposed to 0, 1, and 2mg/kg/day of BDE-99 from gestation day 6 to postnatal day 21. When the pups were weaning, the liver from 1 pup of each litter was excised to evaluate oxidative stress markers and the messenger RNA (mRNA) expression of multiple cytochrome P450 (CYP) isoforms. To determine whether thyroid hormone (TH) was disrupted, the protein and mRNA expressions of several TH receptor (TR) isoforms, as well as the protein levels of cyclin D1 and the phosphorylated protein kinases Akt and glycogen synthase kinase 3 beta (GSK3β), were evaluated. Perinatal exposure to BDE-99 produced decreased levels of cyclin D1 in rat pup livers. A decrease in the active form of Akt and an increase in the active form of GSK3β were observed. The decreased Akt pathway may be due to a potential disruption of the nongenomic actions of TH by BDE-99 and its metabolites. This possible TH disruption was noted as a decrease in TR isoforms expression. By contrast, we observed an upregulation of CYP2B1 gene expression, which is correlated with an increase in reactive oxygen species production. This outcome indicates activation of the nuclear constitutive androstane receptor, which could induce the expression of other enzymes capable of metabolizing TH. The present findings support the hypothesis that perinatal exposure to PBDEs, at levels found in humans, may have serious implications for metabolic processes in rat pup livers.

Reduced hepatic tumor incidence in cyclin G1-deficient mice

DEFF Research Database (Denmark)

Jensen, Michael Rugaard; Factor, Valentina M; Fantozzi, Anna

2003-01-01

found that the p53 levels in the cyclin G1-deficient mice are 2-fold higher that in wild-type mice. Moreover, we showed that treatment of mice with the alkylating agent 1,4-bis[N,N'-di(ethylene)-phosphamide]piperazine (Dipin), followed by partial hepatectomy, decreased G1-S transition in cyclin G1-null...

Targeting CCl4 -induced liver fibrosis by RNA interference-mediated inhibition of cyclin E1 in mice.

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Bangen, Jörg-Martin; Hammerich, Linda; Sonntag, Roland; Baues, Maike; Haas, Ute; Lambertz, Daniela; Longerich, Thomas; Lammers, Twan; Tacke, Frank; Trautwein, Christian; Liedtke, Christian

2017-10-01

Initiation and progression of liver fibrosis requires proliferation and activation of resting hepatic stellate cells (HSCs). Cyclin E1 (CcnE1) is the regulatory subunit of the cyclin-dependent kinase 2 (Cdk2) and controls cell cycle re-entry. We have recently shown that genetic inactivation of CcnE1 prevents activation, proliferation, and survival of HSCs and protects from liver fibrogenesis. The aim of the present study was to translate these findings into preclinical applications using an RNA interference (RNAi)-based approach. CcnE1-siRNA (small interfering RNA) efficiently inhibited CcnE1 gene expression in murine and human HSC cell lines and in primary HSCs, resulting in diminished proliferation and increased cell death. In C57BL/6 wild-type (WT) mice, delivery of stabilized siRNA using a liposome-based carrier targeted approximately 95% of HSCs, 70% of hepatocytes, and 40% of CD45 + cells after single injection. Acute CCl 4 -mediated liver injury in WT mice induced endogenous CcnE1 expression and proliferation of surviving hepatocytes and nonparenchymal cells, including CD45 + leukocytes. Pretreatment with CcnE1-siRNA reverted CcnE1 induction to baseline levels of healthy mice, which was associated with reduced liver injury, diminished proliferation of hepatocytes and leukocytes, and attenuated overall inflammatory response. For induction of liver fibrosis, WT mice were challenged with CCl 4 for 4-6 weeks. Co-treatment with CcnE1-siRNA once a week was sufficient to continuously block CcnE1 expression and cell-cycle activity of hepatocytes and nonparenchymal cells, resulting in significantly ameliorated liver fibrosis and inflammation. Importantly, CcnE1-siRNA also prevented progression of liver fibrosis if applied after onset of chronic liver injury. Therapeutic targeting of CcnE1 in vivo using RNAi is feasible and has high antifibrotic activity. (Hepatology 2017;66:1242-1257). © 2017 by the American Association for the Study of Liver Diseases.

Involvement of cyclin D1/CDK4 and pRb mediated by PI3K/AKT pathway activation in Pb2+-induced neuronal death in cultured hippocampal neurons

International Nuclear Information System (INIS)

Li Chenchen; Xing Tairan; Tang Mingliang; Yong Wu; Yan Dan; Deng Hongmin; Wang Huili; Wang Ming; Chen Jutao; Ruan Diyun

2008-01-01

Lead (Pb) is widely recognized as a neurotoxicant. One of the suggested mechanisms of lead neurotoxicity is apoptotic cell death. And the mechanism by which Pb 2+ causes neuronal death is not well understood. The present study sought to examine the obligate nature of cyclin D1/cyclin-dependent kinase 4 (CDK4), phosphorylation of its substrate retinoblastoma protein (pRb) and its select upstream signal phosphoinositide 3-kinase (PI3K)/AKT pathway in the death of primary cultured rat hippocampal neurons evoked by Pb 2+ . Our data showed that lead treatment of primary hippocampal cultures results in dose-dependent cell death. Inhibition of CDK4 prevented Pb 2+ -induced neuronal death significantly but was incomplete. In addition, we demonstrated that the levels of cyclin D1 and pRb/p107 were increased during Pb 2+ treatment. These elevated expression persisted up to 48 h, returning to control levels after 72 h. We also presented pharmacological and morphological evidences that cyclin D1/CDK4 and pRb/p107 were required for such kind of neuronal death. Addition of the PI3K inhibitor LY294002 (30 μM) or wortmannin (100 nM) significantly rescued the cultured hippocampal neurons from death caused by Pb 2+ . And that Pb 2+ -elicited phospho-AKT (Ser473) participated in the induction of cyclin D1 and partial pRb/p107 expression. These results provide evidences that cell cycle elements play a required role in the death of neurons evoked by Pb 2+ and suggest that certain signaling elements upstream of cyclin D1/CDK4 are modified and/or required for this form of neuronal death

Role of cyclins in controlling progression of mammalian spermatogenesis

OpenAIRE

WOLGEMUTH, DEBRA J.; MANTEROLA, MARCIA; VASILEVA, ANA

2013-01-01

Cyclins are key regulators of the mammalian cell cycle, functioning primarily in concert with their catalytic partners, the cyclin-dependent kinases (Cdks). While their function during mitosis in somatic cells has been extensively documented, their function during both mitosis and meiosis in the germ line is poorly understood. From the perspective of cell cycle regulation there are several aspects of mammalian spermatogenesis that suggest unique modes of regulation and hence, possible unique ...

Identification of extracellular signal-regulated kinase 3 as a new interaction partner of cyclin D3

International Nuclear Information System (INIS)

Sun Maoyun; Wei Yuanyan; Yao Luyang; Xie Jianhui; Chen Xiaoning; Wang Hanzhou; Jiang Jianhai; Gu Jianxin

2006-01-01

Cyclin D3, like cyclin D1 and D2 isoforms, is a crucial component of the core cell cycle machinery in mammalian cells. It also exhibits its unique properties in many other physiological processes. In the present study, using yeast two-hybrid screening, we identified ERK3, an atypical mitogen-activated protein kinase (MAPK), as a cyclin D3 binding partner. GST pull-down assays showed that cyclin D3 interacts directly and specifically with ERK3 in vitro. The binding of cyclin D3 and ERK3 was further confirmed in vivo by co-immunoprecipitation assay and confocal microscopic analysis. Moreover, carboxy-terminal extension of ERK3 was responsible for its association with intact cyclin D3. These findings further expand distinct roles of cyclin D3 and suggest the potential activity of ERK3 in cell proliferation

Direct binding of the N-terminus of HTLV-1 tax oncoprotein to cyclin-dependent kinase 4 is a dominant path to stimulate the kinase activity.

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Li, Junan; Li, Hongyuan; Tsai, Ming-Daw

2003-06-10

The involvement of Tax oncoprotein in the INK4-CDK4/6-Rb pathway has been regarded as a key factor for immortalization and transformation of human T-cell leukemia virus 1 (HTLV-1) infected cells. In both p16 -/- and +/+ cells, expression of Tax has been correlated with an increase in CDK4 activity, which subsequently increases the phosphorylation of Rb and drives the infected cells into cell cycle progression. In relation to these effects, Tax has been shown to interact with two components of the INK4-CDK4/6-Rb pathway, p16 and cyclin D(s). While Tax competes with CDK4 for p16 binding, thus suppressing p16 inhibition of CDK4, Tax also binds to cyclin D(s) with concomitant increases in both CDK4 activity and the phosphorylation of cyclin D(s). Here we show that both Tax and residues 1-40 of the N-terminus of Tax, Tax40N, bind to and activate CDK4 in vitro. In the presence of INK4 proteins, binding of Tax and Tax40N to CDK4 counteracts against the inhibition of p16 and p18 and acts as the major path to regulate Tax-mediated activation of CDK4. We also report that Tax40N retains the transactivation ability. These results of in vitro studies demonstrate a potentially novel, p16-independent route to regulate CDK4 activity by the Tax oncoprotein in HTLV-1 infected cells.

Expression of the p16{sup INK4a} tumor suppressor gene in rodent lung tumors

Energy Technology Data Exchange (ETDEWEB)

Swafford, D.S.; Tesfaigzi, J.; Belinsky, S.A.

1995-12-01

Aberrations on the short arm of chromosome 9 are among the earliest genetic changes in human cancer. p16{sup INK4a} is a candidate tumor suppressor gene that lies within human 9p21, a chromosome region associated with frequent loss of heterozygosity in human lung tumors. The p16{sup INK4a} protein functions as an inhibitor of cyclin D{sub 1}-dependent kinases that phosphorylate the retinoblastoma (Rb) tumor suppressor gene product enabling cell-cycle progression. Thus, overexpression of cyclin D{sub 1}, mutation of cyclin-dependent kinase genes, or loss of p16{sup INK4a} function, can all result in functional inactivation of Rb. Inactivation of Rb by mutation or deletion can result in an increase in p16{sup INK4a} transcription, suggesting that an increased p16{sup INK4a} expression in a tumor cell signals dysfunction of the pathway. The p16{sup (INK4a)} gene, unlike some tumor suppressor genes, is rarely inactivated by mutation. Instead, the expression of this gene is suppressed in some human cancers by hypermethylation of the CpG island within the first exon or by homozygous deletion: 686. Chromosome losses have been observed at 9p21 syntenic loci in tumors of the mouse and rat, two species often used as animal models for pulmonary carcinogenesis. Expression of p16{sup INK4a} is lost in some mouse tumor cell lines, often due to homozygous deletion. These observations indicate that p16{sup INK4a} dysfunction may play a role in the development of neoplasia in rodents as well as humans. The purpose of the current investigation was to define the extent to which p16{sup INK4a} dysfunction contributes to the development of rodent lung tumors and to determine the mechanism of inactivation of the gene. There is no evidence to suggest a loss of function of the p16{sup INK4a} tumor suppressor gene in these primary murine lung tumors by mutation, deletion, or methylation.

Mantle cell lymphoma pathogenesis: another turn of the screw to cyclin D1 overexpression

OpenAIRE

Albero Gallego, Robert

2017-01-01

[eng] Mantle cell lymphoma (MCL) is an aggressive lymphoid neoplasm derived from mature B cells characterized by the presence of the t(11;14)(q13;q32) translocation that leads to the overexpression of Cyclin D1. Cyclin D1 plays a well-established role in G1/S progression, although other functions including transcription or DNA damage response (DDR) can be regulated by this cyclin. Therefore, the main goal of this thesis is the characterization of the cyclin D1 non-canonical function in MCL a...

Mantle cell lymphoma pathogenesis: another turn of the screw to cyclin D1 overexpression

OpenAIRE

Albero Gallego, Robert

2017-01-01

Mantle cell lymphoma (MCL) is an aggressive lymphoid neoplasm derived from mature B cells characterized by the presence of the t(11;14)(q13;q32) translocation that leads to the overexpression of Cyclin D1. Cyclin D1 plays a well-established role in G1/S progression, although other functions including transcription or DNA damage response (DDR) can be regulated by this cyclin. Therefore, the main goal of this thesis is the characterization of the cyclin D1 non-canonical function in MCL and lymp...

Estrogen receptor beta signaling inhibits PDGF induced human airway smooth muscle proliferation.

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Ambhore, Nilesh Sudhakar; Katragadda, Rathnavali; Raju Kalidhindi, Rama Satyanarayana; Thompson, Michael A; Pabelick, Christina M; Prakash, Y S; Sathish, Venkatachalem

2018-04-20

Airway smooth muscle (ASM) cell hyperplasia driven by persistent inflammation is a hallmark feature of remodeling in asthma. Sex steroid signaling in the lungs is of considerable interest, given epidemiological data showing more asthma in pre-menopausal women and aging men. Our previous studies demonstrated that estrogen receptor (ER) expression increases in asthmatic human ASM; however, very limited data are available regarding differential roles of ERα vs. ERβ isoforms in human ASM cell proliferation. In this study, we evaluated the effect of selective ERα and ERβ modulators on platelet-derived growth factor (PDGF)-stimulated ASM proliferation and the mechanisms involved. Asthmatic and non-asthmatic primary human ASM cells were treated with PDGF, 17β-estradiol, ERα-agonist and/or ERβ-agonist and/or G-protein-coupled estrogen receptor 30 (GPR30/GPER) agonist and proliferation was measured using MTT and CyQuant assays followed by cell cycle analysis. Transfection of small interfering RNA (siRNA) ERα and ERβ significantly altered the human ASM proliferation. The specificity of siRNA transfection was confirmed by Western blot analysis. Gene and protein expression of cell cycle-related antigens (PCNA and Ki67) and C/EBP were measured by RT-PCR and Western analysis, along with cell signaling proteins. PDGF significantly increased ASM proliferation in non-asthmatic and asthmatic cells. Treatment with PPT showed no significant effect on PDGF-induced proliferation, whereas WAY interestingly suppressed proliferation via inhibition of ERK1/2, Akt, and p38 signaling. PDGF-induced gene expression of PCNA, Ki67 and C/EBP in human ASM was significantly lower in cells pre-treated with WAY. Furthermore, WAY also inhibited PDGF-activated PCNA, C/EBP, cyclin-D1, and cyclin-E. Overall, we demonstrate ER isoform-specific signaling in the context of ASM proliferation. Activation of ERβ can diminish remodeling in human ASM by inhibiting pro-proliferative signaling pathways

Modulation of Cyclins, p53 and Mitogen-Activated Protein Kinases Signaling in Breast Cancer Cell Lines by 4-(3,4,5-Trimethoxyphenoxybenzoic Acid

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Kuan-Han Lee

2014-01-01

Full Text Available Despite the advances in cancer therapy and early detection, breast cancer remains a leading cause of cancer-related deaths among females worldwide. The aim of the current study was to investigate the antitumor activity of a novel compound, 4-(3,4,5-trimethoxyphenoxybenzoic acid (TMPBA and its mechanism of action, in breast cancer. Results indicated the relatively high sensitivity of human breast cancer cell-7 and MDA-468 cells towards TMPBA with IC50 values of 5.9 and 7.9 µM, respectively compared to hepatocarcinoma cell line Huh-7, hepatocarcinoma cell line HepG2, and cervical cancer cell line Hela cells. Mechanistically, TMPBA induced apoptotic cell death in MCF-7 cells as indicated by 4',6-diamidino-2-phenylindole (DAPI nuclear staining, cell cycle analysis and the activation of caspase-3. Western blot analysis revealed the ability of TMPBA to target pathways mediated by mitogen-activated protein (MAP kinases, 5' adenosine monophosphate-activated protein kinase (AMPK, and p53, of which the concerted action underlined its antitumor efficacy. In addition, TMPBA induced alteration of cyclin proteins’ expression and consequently modulated the cell cycle. Taken together, the current study underscores evidence that TMPBA induces apoptosis in breast cancer cells via the modulation of cyclins and p53 expression as well as the modulation of AMPK and mitogen-activated protein kinases (MAPK signaling. These findings support TMPBA’s clinical promise as a potential candidate for breast cancer therapy.

Characterisation of cell cycle arrest and terminal differentiation in a maximally proliferative human epithelial tissue: Lessons from the human hair follicle matrix.

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Purba, Talveen S; Brunken, Lars; Peake, Michael; Shahmalak, Asim; Chaves, Asuncion; Poblet, Enrique; Ceballos, Laura; Gandarillas, Alberto; Paus, Ralf

2017-09-01

Human hair follicle (HF) growth and hair shaft formation require terminal differentiation-associated cell cycle arrest of highly proliferative matrix keratinocytes. However, the regulation of this complex event remains unknown. CIP/KIP family member proteins (p21 CIP1 , p27 KIP1 and p57 KIP2 ) regulate cell cycle progression/arrest, endoreplication, differentiation and apoptosis. Since they have not yet been adequately characterized in the human HF, we asked whether and where CIP/KIP proteins localise in the human hair matrix and pre-cortex in relation to cell cycle activity and HF-specific epithelial cell differentiation that is marked by keratin 85 (K85) protein expression. K85 expression coincided with loss or reduction in cell cycle activity markers, including in situ DNA synthesis (EdU incorporation), Ki-67, phospho-histone H3 and cyclins A and B1, affirming a post-mitotic state of pre-cortical HF keratinocytes. Expression of CIP/KIP proteins was found abundantly within the proliferative hair matrix, concomitant with a role in cell cycle checkpoint control. p21 CIP1 , p27 KIP1 and cyclin E persisted within post-mitotic keratinocytes of the pre-cortex, whereas p57 KIP2 protein decreased but became nuclear. These data imply a supportive role for CIP/KIP proteins in maintaining proliferative arrest, differentiation and anti-apoptotic pathways, promoting continuous hair bulb growth and hair shaft formation in anagen VI. Moreover, post-mitotic hair matrix regions contained cells with enlarged nuclei, and DNA in situ hybridisation showed cells that were >2N in the pre-cortex. This suggests that CIP/KIP proteins might counterbalance cyclin E to control further rounds of DNA replication in a cell population that has a propensity to become tetraploid. These data shed new light on the in situ-biography of human hair matrix keratinocytes on their path of active cell cycling, arrest and terminal differentiation, and showcase the human HF as an excellent, clinically

Automated Quantitative Analysis of p53, Cyclin D1, Ki67 and pERK Expression in Breast Carcinoma Does Not Differ from Expert Pathologist Scoring and Correlates with Clinico-Pathological Characteristics

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Cass, Jamaica D. [Division of Cancer Biology and Genetics, Cancer Research Institute, Queen’s University, Kingston K7L 3N6 (Canada); Varma, Sonal [Department of Pathology and Molecular Medicine, Queen’s University, Kingston K7L 3N6 (Canada); Day, Andrew G. [Kingston General Hospital, Kingston K7L 2V7 (Canada); Sangrar, Waheed [Division of Cancer Biology and Genetics, Cancer Research Institute, Queen’s University, Kingston K7L 3N6 (Canada); Rajput, Ashish B. [Department of Pathology and Molecular Medicine, Queen’s University, Kingston K7L 3N6 (Canada); Raptis, Leda H.; Squire, Jeremy [Division of Cancer Biology and Genetics, Cancer Research Institute, Queen’s University, Kingston K7L 3N6 (Canada); Madarnas, Yolanda [Department of Oncology, Queen’s University, Kingston K7L 3N6 (Canada); SenGupta, Sandip K. [Department of Pathology and Molecular Medicine, Queen’s University, Kingston K7L 3N6 (Canada); Elliott, Bruce E., E-mail: elliottb@queensu.ca [Division of Cancer Biology and Genetics, Cancer Research Institute, Queen’s University, Kingston K7L 3N6 (Canada); Department of Pathology and Molecular Medicine, Queen’s University, Kingston K7L 3N6 (Canada)

2012-07-18

There is critical need for improved biomarker assessment platforms which integrate traditional pathological parameters (TNM stage, grade and ER/PR/HER2 status) with molecular profiling, to better define prognostic subgroups or systemic treatment response. One roadblock is the lack of semi-quantitative methods which reliably measure biomarker expression. Our study assesses reliability of automated immunohistochemistry (IHC) scoring compared to manual scoring of five selected biomarkers in a tissue microarray (TMA) of 63 human breast cancer cases, and correlates these markers with clinico-pathological data. TMA slides were scanned into an Ariol Imaging System, and histologic (H) scores (% positive tumor area x staining intensity 0–3) were calculated using trained algorithms. H scores for all five biomarkers concurred with pathologists’ scores, based on Pearson correlation coefficients (0.80–0.90) for continuous data and Kappa statistics (0.55–0.92) for positive vs. negative stain. Using continuous data, significant association of pERK expression with absence of LVI (p = 0.005) and lymph node negativity (p = 0.002) was observed. p53 over-expression, characteristic of dysfunctional p53 in cancer, and Ki67 were associated with high grade (p = 0.032 and 0.0007, respectively). Cyclin D1 correlated inversely with ER/PR/HER2-ve (triple negative) tumors (p = 0.0002). Thus automated quantitation of immunostaining concurs with pathologists’ scoring, and provides meaningful associations with clinico-pathological data.

Automated Quantitative Analysis of p53, Cyclin D1, Ki67 and pERK Expression in Breast Carcinoma Does Not Differ from Expert Pathologist Scoring and Correlates with Clinico-Pathological Characteristics

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Cass, Jamaica D.; Varma, Sonal; Day, Andrew G.; Sangrar, Waheed; Rajput, Ashish B.; Raptis, Leda H.; Squire, Jeremy; Madarnas, Yolanda; SenGupta, Sandip K.; Elliott, Bruce E.

2012-01-01

There is critical need for improved biomarker assessment platforms which integrate traditional pathological parameters (TNM stage, grade and ER/PR/HER2 status) with molecular profiling, to better define prognostic subgroups or systemic treatment response. One roadblock is the lack of semi-quantitative methods which reliably measure biomarker expression. Our study assesses reliability of automated immunohistochemistry (IHC) scoring compared to manual scoring of five selected biomarkers in a tissue microarray (TMA) of 63 human breast cancer cases, and correlates these markers with clinico-pathological data. TMA slides were scanned into an Ariol Imaging System, and histologic (H) scores (% positive tumor area x staining intensity 0–3) were calculated using trained algorithms. H scores for all five biomarkers concurred with pathologists’ scores, based on Pearson correlation coefficients (0.80–0.90) for continuous data and Kappa statistics (0.55–0.92) for positive vs. negative stain. Using continuous data, significant association of pERK expression with absence of LVI (p = 0.005) and lymph node negativity (p = 0.002) was observed. p53 over-expression, characteristic of dysfunctional p53 in cancer, and Ki67 were associated with high grade (p = 0.032 and 0.0007, respectively). Cyclin D1 correlated inversely with ER/PR/HER2-ve (triple negative) tumors (p = 0.0002). Thus automated quantitation of immunostaining concurs with pathologists’ scoring, and provides meaningful associations with clinico-pathological data

TSA-induced JMJD2B downregulation is associated with cyclin B1-dependent survivin degradation and apoptosis in LNCap cells.

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Zhu, Shan; Li, Yueyang; Zhao, Li; Hou, Pingfu; Shangguan, Chenyan; Yao, Ruosi; Zhang, Weina; Zhang, Yu; Tan, Jiang; Huang, Baiqu; Lu, Jun

2012-07-01

Histone deacetylase (HDAC) inhibitors are emerging as a novel class of anti-tumor agents and have manifested the ability to induce apoptosis of cancer cells, and a significant number of genes have been identified as potential effectors responsible for HDAC inhibitor-induced apoptosis. However, the mechanistic actions of these HDAC inhibitors in this process remain largely undefined. We here report that the treatment of LNCap prostate cancer cells with HDAC inhibitor trichostatin A (TSA) resulted in downregulation of the Jumonji domain-containing protein 2B (JMJD2B). We also found that the TSA-mediated decrease in survivin expression in LNCap cells was partly attributable to downregulation of JMJD2B expression. This effect was attributable to the promoted degradation of survivin protein through inhibition of Cyclin B1/Cdc2 complex-mediated survivin Thr34 phosphorylation. Consequently, knockdown of JMJD2B enhanced TSA-induced apoptosis by regulating the Cyclin B1-dependent survivin degradation to potentiate the apoptosis pathways. Copyright © 2012 Wiley Periodicals, Inc.

CD274 promotes cell cycle entry of leukemia-initiating cells through JNK/Cyclin D2 signaling

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Xia Fang

2016-11-01

Full Text Available Abstract Background CD274 (programmed death ligand 1, also known as B7H1 is expressed in both solid tumors and hematologic malignancies and is of critical importance for the escape of tumor cells from immune surveillance by inhibiting T cell function via its receptor, programmed death 1 (PD-1. Increasing evidence indicates that functional monoclonal antibodies of CD274 may potently enhance the antitumor effect in many cancers. However, the role of CD274 in leukemia-initiating cells (LICs remains largely unknown. Methods We established an MLL-AF9-induced acute myeloid leukemia (AML model with wild-type (WT and CD274-null mice to elucidate the role of CD274 in the cell fates of LICs, including self-renewal, differentiation, cell cycle, and apoptosis. RNA sequencing was performed to reveal the potential downstream targets, the results of which were further validated both in vitro and in vivo. Results In silico analysis indicated that CD274 level was inversely correlated with the overall survival of AML patients. In Mac-1+/c-Kit+ mouse LICs, CD274 was expressed at a much higher level than in the normal hematopoietic stem cells (HSCs. The survival of the mice with CD274-null leukemia cells was dramatically extended during the serial transplantation compared with that of their WT counterparts. CD274 deletion led to a significant decrease in LIC frequency and arrest in the G1 phase of the cell cycle. Interestingly, CD274 is not required for the maintenance of HSC pool as shown in our previous study. Mechanistically, we demonstrated that the levels of both phospho-JNK and Cyclin D2 were strikingly downregulated in CD274-null LICs. The overexpression of Cyclin D2 fully rescued the loss of function of CD274. Moreover, CD274 was directly associated with JNK and enhanced the downstream signaling to increase the Cyclin D2 level, promoting leukemia development. Conclusions The surface immune molecule CD274 plays a critical role in the proliferation of LICs

Cyclin A2 promotes DNA repair in the brain during both development and aging.

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Gygli, Patrick E; Chang, Joshua C; Gokozan, Hamza N; Catacutan, Fay P; Schmidt, Theresa A; Kaya, Behiye; Goksel, Mustafa; Baig, Faisal S; Chen, Shannon; Griveau, Amelie; Michowski, Wojciech; Wong, Michael; Palanichamy, Kamalakannan; Sicinski, Piotr; Nelson, Randy J; Czeisler, Catherine; Otero, José J

2016-07-01

Various stem cell niches of the brain have differential requirements for Cyclin A2. Cyclin A2 loss results in marked cerebellar dysmorphia, whereas forebrain growth is retarded during early embryonic development yet achieves normal size at birth. To understand the differential requirements of distinct brain regions for Cyclin A2, we utilized neuroanatomical, transgenic mouse, and mathematical modeling techniques to generate testable hypotheses that provide insight into how Cyclin A2 loss results in compensatory forebrain growth during late embryonic development. Using unbiased measurements of the forebrain stem cell niche, we parameterized a mathematical model whereby logistic growth instructs progenitor cells as to the cell-types of their progeny. Our data was consistent with prior findings that progenitors proliferate along an auto-inhibitory growth curve. The growth retardation inCCNA2-null brains corresponded to cell cycle lengthening, imposing a developmental delay. We hypothesized that Cyclin A2 regulates DNA repair and that CCNA2-null progenitors thus experienced lengthened cell cycle. We demonstrate that CCNA2-null progenitors suffer abnormal DNA repair, and implicate Cyclin A2 in double-strand break repair. Cyclin A2's DNA repair functions are conserved among cell lines, neural progenitors, and hippocampal neurons. We further demonstrate that neuronal CCNA2 ablation results in learning and memory deficits in aged mice.

Regulation of sonic hedgehog-GLI1 downstream target genes PTCH1, Cyclin D2, Plakoglobin, PAX6 and NKX2.2 and their epigenetic status in medulloblastoma and astrocytoma

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Eberhart Charles G

2010-11-01

Full Text Available Abstract Background The Sonic hedgehog (Shh signaling pathway is critical for cell growth and differentiation. Impairment of this pathway can result in both birth defects and cancer. Despite its importance in cancer development, the Shh pathway has not been thoroughly investigated in tumorigenesis of brain tumors. In this study, we sought to understand the regulatory roles of GLI1, the immediate downstream activator of the Shh signaling pathway on its downstream target genes PTCH1, Cyclin D2, Plakoglobin, NKX2.2 and PAX6 in medulloblastoma and astrocytic tumors. Methods We silenced GLI1 expression in medulloblastoma and astrocytic cell lines by transfection of siRNA against GLI1. Subsequently, we performed RT-PCR and quantitative real time RT-PCR (qRT-PCR to assay the expression of downstream target genes PTCH1, Cyclin D2, Plakoglobin, NKX2.2 and PAX6. We also attempted to correlate the pattern of expression of GLI1 and its regulated genes in 14 cell lines and 41 primary medulloblastoma and astrocytoma tumor samples. We also assessed the methylation status of the Cyclin D2 and PTCH1 promoters in these 14 cell lines and 58 primary tumor samples. Results Silencing expression of GLI1 resulted up-regulation of all target genes in the medulloblastoma cell line, while only PTCH1 was up-regulated in astrocytoma. We also observed methylation of the cyclin D2 promoter in a significant number of astrocytoma cell lines (63% and primary astrocytoma tumor samples (32%, but not at all in any medulloblastoma samples. PTCH1 promoter methylation was less frequently observed than Cyclin D2 promoter methylation in astrocytomas, and not at all in medulloblastomas. Conclusions Our results demonstrate different regulatory mechanisms of Shh-GLI1 signaling. These differences vary according to the downstream target gene affected, the origin of the tissue, as well as epigenetic regulation of some of these genes.

Toona Sinensis Extracts Induced Cell Cycle Arrest and Apoptosis in the Human Lung Large Cell Carcinoma

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Cheng-Yuan Wang

2010-02-01

Full Text Available Toona sinensis extracts have been shown to exhibit anti-cancer effects in human ovarian cancer cell lines, human promyelocytic leukemia cells and human lung adenocarcinoma. Its safety has also been confirmed in animal studies. However, its anti-cancer properties in human lung large cell carcinoma have not been studied. Here, we used a powder obtained by freeze-drying the super-natant of centrifuged crude extract from Toona sinensis leaves (TSL-1 to treat the human lung carcinoma cell line H661. Cell viability was evaluated by the 3-(4-,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide assay. Flow cytometry analysis revealed that TSL-1 blocked H661 cell cycle progression. Western blot analysis showed decreased expression of cell cycle proteins that promote cell cycle progression, including cyclin-dependent kinase 4 and cyclin D1, and increased the expression of proteins that inhibit cell cycle progression, including p27. Furthermore, flow cytometry analysis showed that TSL-1 induced H661 cell apoptosis. Western blot analysis showed that TSL-1 reduced the expression of the anti-apoptotic protein B-cell lymphoma 2, and degraded the DNA repair protein, poly(ADP-ribose polymerase. TSL-1 shows potential as a novel therapeutic agent or for use as an adjuvant for treating human lung large cell carcinoma.

Addition of rituximab to chemotherapy overcomes the negative prognostic impact of cyclin E expression in diffuse large B-cell lymphoma

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Frei, E; Visco, C; Xu-Monette, Z Y

2013-01-01

High levels of cyclin E (CCNE) are accompanied by shorter survival in cyclophosphamide, hydroxydaunorubicin, oncovin and prednisone (CHOP)-treated diffuse large B-cell lymphomas (DLBCL), independent of the international prognostic index (IPI). Data on the prognostic role of CCNE in the 'rituximab...

[Effects of Biejiajian Pills on Wnt signal pathway signal molecules β-catenin/TCF4 complex activities and downstream proteins cyclin D1 and MMP-2 in hepatocellular carcinoma cells].

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Wen, Bin; Sun, Haitao; He, Songqi; Cheng, Yang; Jia, Wenyan; Fan, Eryan; Pang, Jie

2014-12-01

To study the effect of Biejiajian Pills on Wnt signal pathway and the mechanisms underlying its action to suppress the invasiveness of hepatocellular carcinoma. HepG2 cells cultured in the serum of rats fed with Biejiajian Pills for 48 h were examined for β-catenin expression using immunofluorescence, β-catenin/TCF4 complex activity with luciferase, and expressions of the downstream proteins cyclin D1 and MMP-2 using qRT-PCR. Biejiajian Pills-treated sera significantly reduced the expressions of cytoplasmic and nuclear β-catenin protein, cyclin D1 and MMP-2 proteins and lowered the activities of β-catenin/TCF4 complex. Biejiajian Pills may serve as a potential anti-tumor agent, whose effect might be mediated by inhibiting the Wnt/β-catenin pathway.

Tumor necrosis factor-alpha inhibits differentiation of myogenic cells in human urethral rhabdosphincter.

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Shinohara, Mayuka; Sumino, Yasuhiro; Sato, Fuminori; Kiyono, Tohru; Hashimoto, Naohiro; Mimata, Hiromitsu

2017-06-01

To examine the inhibitory effects of tumor necrosis factor-α on myogenic differentiation of human urethral rhabdosphincter cells. A rhabdosphincter sample was obtained from a patient who underwent total cystectomy. To expand the lifespan of the primary cultured cells, rhabdosphincter myogenic cells were immortalized with mutated cyclin-dependent kinase 4, cyclin D1 and telomerase. The differential potential of the cells was investigated. The transfected human rhabdosphincter cells were induced for myogenic differentiation with recombinant human tumor necrosis factor-α and/or the tumor necrosis factor-α antagonist etanercept at different concentrations, and activation of signaling pathways was monitored. Human rhabdosphincter cells were selectively cultured for at least 40 passages. Molecular analysis confirmed the expression of myosin heavy chain, which is a specific marker of differentiated muscle cells, significantly increased after differentiation induction. Although tumor necrosis factor-α treatment reduced the myosin heavy chain expression in a concentration-dependent manner, etanercept inhibited this suppression. Tumor necrosis factor-α suppressed phosphorylation of protein kinase B and p38, whereas etanercept pretreatment promoted phosphorylation and myosin heavy chain expression in a concentration-dependent manner. Tumor necrosis factor-α inhibits differentiation of urethral rhabdosphincter cells in part through the p38 mitogen-activated protein kinase and phosphoinositide 3-kinase pathways. Inhibition of tumor necrosis factor-α might be a useful strategy to treat stress urinary incontinence. © 2017 The Japanese Urological Association.

SUMO modification of Stra13 is required for repression of cyclin D1 expression and cellular growth arrest.

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Yaju Wang

Full Text Available Stra13, a basic helix-loop-helix (bHLH transcription factor is involved in myriad biological functions including cellular growth arrest, differentiation and senescence. However, the mechanisms by which its transcriptional activity and function are regulated remain unclear. In this study, we provide evidence that post-translational modification of Stra13 by Small Ubiquitin-like Modifier (SUMO dramatically potentiates its ability to transcriptionally repress cyclin D1 and mediate G(1 cell cycle arrest in fibroblast cells. Mutation of SUMO acceptor lysines 159 and 279 located in the C-terminal repression domain has no impact on nuclear localization; however, it abrogates association with the co-repressor histone deacetylase 1 (HDAC1, attenuates repression of cyclin D1, and prevents Stra13-mediated growth suppression. HDAC1, which promotes cellular proliferation and cell cycle progression, antagonizes Stra13 sumoylation-dependent growth arrest. Our results uncover an unidentified regulatory axis between Stra13 and HDAC1 in progression through the G(1/S phase of the cell cycle, and provide new mechanistic insights into regulation of Stra13-mediated transcriptional repression by sumoylation.

Impaired liver regeneration is associated with reduced cyclin B1 in natural killer T cell-deficient mice.

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Ben Ya'acov, Ami; Meir, Hadar; Zolotaryova, Lydia; Ilan, Yaron; Shteyer, Eyal

2017-03-23

It has been shown that the proportion of natural killer T cells is markedly elevated during liver regeneration and their activation under different conditions can modulate this process. As natural killer T cells and liver injury are central in liver regeneration, elucidating their role is important. The aim of the current study is to explore the role of natural killer T cells in impaired liver regeneration. Concanvalin A was injected 4 days before partial hepatectomy to natural killer T cells- deficient mice or to anti CD1d1-treated mice. Ki-67 and proliferating cell nuclear antigen were used to measure hepatocytes proliferation. Expression of hepatic cyclin B1 and proliferating cell nuclear antigen were evaluated by Western Blot and liver injury was assessed by ALT and histology. Natural killer T cells- deficient or mice injected with anti CD1d antibodies exhibited reduced liver regeneration. These mice were considerably resistant to ConA-induced liver injury. In the absence of NKT cells hepatic proliferating cell nuclear antigen and cyclin B1 decreased in mice injected with Concanvalin A before partial hepatectomy. This was accompanied with reduced serum interleukin-6 levels. Natural killer T cells play an important role in liver regeneration, which is associated with cyclin B1 and interleukin-6.

Frequency of polymorphisms and protein expression of cyclin-dependent kinase inhibitor 1A (CDKN1A in central nervous system tumors

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Mev Dominguez Valentin

Full Text Available CONTEXT AND OBJECTIVE: Genetic investigation of central nervous system (CNS tumors provides valuable information about the genes regulating proliferation, differentiation, angiogenesis, migration and apoptosis in the CNS. The aim of our study was to determine the prevalence of genetic polymorphisms (codon 31 and 3' untranslated region, 3'UTR and protein expression of the cyclin-dependent kinase inhibitor 1A (CDKN1A gene in patients with and without CNS tumors. DESIGN AND SETTING: Analytical cross-sectional study with a control group, at the Molecular Biology Laboratory, Pediatric Oncology Department, Hospital das Clínicas de Ribeirão Preto. METHODS: 41 patients with CNS tumors and a control group of 161 subjects without cancer and paires for sex, age and ethnicity were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP. Protein analysis was performed on 36 patients with CNS tumors, using the Western Blotting technique. RESULTS: The frequencies of the heterozygote (Ser/Arg and polymorphic homozygote (Arg/Arg genotypes of codon 31 in the control subjects were 28.0% and 1.2%, respectively. However, the 3'UTR site presented frequencies of 24.2% (C/T and 0.6% (T/T. These frequencies were not statistically different (P > 0.05 from those seen in the patients with CNS tumors (19.4% and 0.0%, codon 31; 15.8% and 2.6%, 3'UTR site. Regarding the protein expression in ependymomas, 66.67% did not express the protein CDKN1A. The results for medulloblastomas and astrocytomas were similar: neither of them expressed the protein (57.14% and 61.54%, respectively. CONCLUSION: No significant differences in protein expression patterns or polymorphisms of CDKN1A in relation to the three types of CNS tumors were observed among Brazilian subjects.

Cyclin D1-AR Crosstalk: Potential Implications for Therapeutic Response in Prostate Cancer

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2013-06-01

metastatic androgen-independent prostate cancer. Clin Cancer Res 2004; 10: 924–928. 12 Toogood PL, Harvey PJ, Repine JT, Sheehan DJ, VanderWel SN, Zhou H et...al. Discovery of a potent and selective inhibitor of cyclin-dependent kinase 4/6. J Med Chem 2005; 48: 2388–2406. 13 Fry DW, Harvey PJ, Keller PR...cyclin- dependent kinase 6 specific inhibition. J Med Chem 2006; 49: 3826–3831. 58 Lim JT, Mansukhani M, Weinstein IB. Cyclin-dependent kinase 6

Expression of p16(INK4A) gene in human pituitary tumours.

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Machiavelli, Gloria; Cotignola, Javier; Danilowicz, Karina; Carbonara, Carolina; Paes de Lima, Andrea; Basso, Armando; Bruno, Oscar Domingo; Szijan, Irene

2008-01-01

Pituitary adenomas comprise 10-15% of primary intracranial tumours but the mechanisms leading to tumour development are yet to be clearly established. The retinoblastoma pathway, which regulates the progression through the cell cycle, is often deregulated in different types of tumours. We studied the cyclin-dependent kinase inhibitor p16(INK4A) gene expression at mRNA level in human pituitary adenomas. Forty-six tumour specimens of different subtypes, 21 clinically non-functioning, 12 growth hormone-secreting, 6 prolactin-secreting, 6 adrenocorticotropin-secreting, and 1 thyrotropin-secreting tumours were studied. All clinically non-functioning and most of the hormone-secreting tumours were macroadenomas (38/46). The RT-PCR assay and electrophoresis of the PCR-products showed that p16(INK4A) mRNA was undetectable in: 62% of non-functioning, 8% of growth hormone-secreting, 17% of prolactin-secreting and 17% of adrenocorticotropin-secreting adenomas. Forty percent of all macroadenomas and 25% of microadenomas had negative p16(INK4A) mRNA, the latter results suggest that the absence of p16(INK4A) product might be an early event in tumours with no expression of this suppressor gene. Within the non-functioning adenomas 63% were "null cell" and 37% were positive for some hormone, both subgroups showed similar percentage of cases with absence of p16(INK4A) mRNA. Our results show that clinically non-functioning macroadenomas have impaired p16(INK4A) expression in a clearly higher proportion than any other pituitary tumour subtype investigated. Other regulatory pathways may be implicated in the development of tumours with positive p16(INK4A) expression.

Sulforaphane, a Dietary Isothiocyanate, Induces G2/M Arrest in Cervical Cancer Cells through CyclinB1 Downregulation and GADD45β/CDC2 Association

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Ya-Min Cheng

2016-09-01

Full Text Available Globally, cervical cancer is the most common malignancy affecting women. The main treatment methods for this type of cancer include conization or hysterectomy procedures. Sulforaphane (SFN is a natural, compound-based drug derived from dietary isothiocyanates which has previously been shown to possess potent anti-tumor and chemopreventive effects against several types of cancer. The present study investigated the effects of SFN on anti-proliferation and G2/M phase cell cycle arrest in cervical cancer cell lines (Cx, CxWJ, and HeLa. We found that cytotoxicity is associated with an accumulation of cells in the G2/M phases of the cell-cycle. Treatment with SFN led to cell cycle arrest as well as the down-regulation of Cyclin B1 expression, but not of CDC2 expression. In addition, the effects of GADD45β gene activation in cell cycle arrest increase proportionally with the dose of SFN; however, mitotic delay and the inhibition of proliferation both depend on the dosage of SFN used to treat cancer cells. These results indicate that SFN may delay the development of cancer by arresting cell growth in the G2/M phase via down-regulation of Cyclin B1 gene expression, dissociation of the cyclin B1/CDC2 complex, and up-regulation of GADD45β proteins.

Coating independent cytotoxicity of citrate- and PEG-coated silver nanoparticles on a human hepatoma cell line.

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Bastos, Verónica; Ferreira-de-Oliveira, José M P; Carrola, Joana; Daniel-da-Silva, Ana L; Duarte, Iola F; Santos, Conceição; Oliveira, Helena

2017-01-01

The antibacterial potential of silver nanoparticles (AgNPs) resulted in their increasing incorporation into consumer, industrial and biomedical products. Therefore, human and environmental exposure to AgNPs (either as an engineered product or a contaminant) supports the emergent research on the features conferring them different toxicity profiles. In this study, 30nm AgNPs coated with citrate or poly(ethylene glycol) (PEG) were used to assess the influence of coating on the effects produced on a human hepatoma cell line (HepG2), namely in terms of viability, apoptosis, apoptotic related genes, cell cycle and cyclins gene expression. Both types of coated AgNPs decreased cell proliferation and viability with a similar toxicity profile. At the concentrations used (11 and 5μg/mL corresponding to IC50 and ~IC10 levels, respectively) the amount of cells undergoing apoptosis was not significant and the apoptotic related genes BCL2 (anti-apoptotic gene) and BAX (pro-apoptotic gene) were both downregulated. Moreover, both AgNPs affected HepG2 cell cycle progression at the higher concentration (11μg/mL) by increasing the percentage of cells in S (synthesis phase) and G2 (Gap 2 phase) phases. Considering the cell-cycle related genes, the expression of cyclin B1 and cyclin E1 genes were decreased. Thus, this work has shown that citrate- and PEG-coated AgNPs impact on HepG2 apoptotic gene expression, cell cycle dynamics and cyclin regulation in a similar way. More research is needed to determine the properties that confer AgNPs at lower toxicity, since their use has proved helpful in several industrial and biomedical contexts. Copyright © 2016. Published by Elsevier B.V.

The Role of Cyclin D1 in the Chemoresistance of Mantle Cell Lymphoma

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2017-09-01

AWARD NUMBER: W81XWH-15-1-0297 TITLE: The Role of Cyclin D1 in the Chemoresistance of Mantle Cell Lymphoma PRINCIPAL INVESTIGATOR: Vu Ngo...AND SUBTITLE The Role of Cyclin D1 in the Chemoresistance of Mantle Cell Lymphoma 5a. CONTRACT NUMBER The Role of Cyclin D1 in the Chemoresistance of...Mantle Cell Lymphoma 5b. GRANT NUMBER GRANT1173 9905 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Vu Ngo 5e. TASK NUMBER E

The human cyclin B1 protein modulates sensitivity of DNA mismatch repair deficient prostate cancer cell lines to alkylating agents.

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Rasmussen, L J; Rasmussen, M; Lützen, A; Bisgaard, H C; Singh, K K

2000-05-25

DNA damage caused by alkylating agents results in a G2 checkpoint arrest. DNA mismatch repair (MMR) deficient cells are resistant to killing by alkylating agents and are unable to arrest the cell cycle in G2 phase after alkylation damage. We investigated the response of two MMR-deficient prostate cancer cell lines DU145 and LNCaP to the alkylating agent MNNG. Our studies reveal that DU145 cancer cells are more sensitive to killing by MNNG than LNCaP. Investigation of the underlying reasons for lower resistance revealed that the DU145 cells contain low endogenous levels of cyclin B1. We provide direct evidence that the endogenous level of cyclin B1 modulates the sensitivity of MMR-deficient prostate cancer cells to alkylating agents.

Isolation of a dinoflagellate mitotic cyclin by functional complementation in yeast

International Nuclear Information System (INIS)

Bertomeu, Thierry; Morse, David

2004-01-01

Dinoflagellates are parasite with permanently condensed chromosomes that lack histones and whose nuclear membrane remains intact during mitosis. These unusual nuclear characters have suggested that the typical cell cycle regulators might be slightly different than those in more typical eukaryotes. To test this, a cyclin has been isolated from the dinoflagellate Gonyaulax polyedra by functional complementation in cln123 mutant yeast. This GpCyc1 sequence contains two cyclin domains in its C-terminal region and a degradation box typical of mitotic cyclins. Similar to other dinoflagellate genes, GpCyc1 has a high copy number, with ∼5000 copies found in the Gonyaulax genome. An antibody raised against the N-terminal region of the GpCYC1 reacts with a 68 kDa protein on Western blots that is more abundant in cell cultures enriched for G2-phase cells than in those containing primarily G1-phase cells, indicating its cellular level follows a pattern expected for a mitotic cyclin. This is the first report of a cell cycle regulator cloned and sequenced from a dinoflagellate, and our results suggest control of the dinoflagellate cell cycle will be very similar to that of other organisms

Role of immunoexpression of cyclin D1, D3, retinoblastoma (Rb mutant and clinical risk factors on complete mole as risk factors of persistent mole

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Yudi M Hidayat

2015-10-01

Full Text Available Introduction: Changes in complete hydatidiform mole (CHM that become persistent are difficult to handle because the malignant pathogenesis of CHM is still unclear. The growth of abnormal cells in CHM is thought to be caused by cell cycle abnormalities. Some components that play a role in this phase include cyclin D and retinoblastoma (Rb. The aim of our study was to determine the role of clinical risk factors, as well as cyclin D1, cyclin D3 and Rb-protein, in the occurrence of persistent moles. Materials and Method: This study involves 68 CHM cases at Dr. Hasan Sadikin Hospital from 2007–2011. The protein expression of cyclin D1, cyclin D3, and Rb were determined by immunohistochemistry. The results were analyzed by comparing the two groups of CHM that became persistent to those that returned to normal, as determined by a Mochizuki regression curve assessment. Results: 20 cases (29% of CHM became persistent and that 48 cases (71% returned to normal. Significant clinical variables were age (p 0.05. Conclusion: There is a strong relationship between clinical risk factors of age, excessive proliferation histopathology, serum βhCG levels ≥100,000 mU/mL, cyclin D1 and Rb mutations with the incidence of persistent moles after the evacuation of the CHM. We proposed a model to predict the risks of persistent moles with a cut-off point of 2.384, which can be used as a reference for patients with CHM.

Characterization of cyclin-dependent kinases and Cdc2/Cdc28 kinase subunits in Trichomonas vaginalis.

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Amador, Erick; López-Pacheco, Karla; Morales, Nataly; Coria, Roberto; López-Villaseñor, Imelda

2017-04-01

Cyclin-dependent kinases (CDKs) have important roles in regulating key checkpoints between stages of the cell cycle. Their activity is tightly regulated through a variety of mechanisms, including through binding with cyclin proteins and the Cdc2/Cdc28 kinase subunit (CKS), and their phosphorylation at specific amino acids. Studies of the components involved in cell cycle control in parasitic protozoa are limited. Trichomonas vaginalis is the causative agent of trichomoniasis in humans and is therefore important in public health; however, some of the basic biological processes used by this organism have not been defined. Here, we characterized proteins potentially involved in cell cycle regulation in T. vaginalis. Three genes encoding protein kinases were identified in the T. vaginalis genome, and the corresponding recombinant proteins (TvCRK1, TvCRK2, TvCRK5) were studied. These proteins displayed similar sequence features to CDKs. Two genes encoding CKSs were also identified, and the corresponding recombinant proteins were found to interact with TvCRK1 and TvCRK2 by a yeast two-hybrid system. One putative cyclin B protein from T. vaginalis was found to bind to and activate the kinase activities of TvCRK1 and TvCRK5, but not TvCRK2. This work is the first characterization of proteins involved in cell cycle control in T. vaginalis.

PARK2 orchestrates cyclins to avoid cancer

Czech Academy of Sciences Publication Activity Database

Bartek, Jiří; Hodný, Zdeněk

2014-01-01

Roč. 46, č. 6 (2014), s. 527-528 ISSN 1061-4036 Institutional support: RVO:68378050 Keywords : PARK2 * G1/S-phase cyclin * cancer Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 29.352, year: 2014

RBP-J-interacting and tubulin-associated protein induces apoptosis and cell cycle arrest in human hepatocellular carcinoma by activating the p53–Fbxw7 pathway

International Nuclear Information System (INIS)

Wang, Haihe; Yang, Zhanchun; Liu, Chunbo; Huang, Shishun; Wang, Hongzhi; Chen, Yingli; Chen, Guofu

2014-01-01

Highlights: • RITA overexpression increased protein expression of p53 and Fbxw7 and downregulated the expression of cyclin D1, cyclin E, CDK2, Hes-1 and NF-κB p65. • RITA can significantly inhibit the in vitro growth of SMMC7721 and HepG2 cells. • RITA exerts tumor-suppressive effects in hepatocarcinogenesis through induction of G0/G1 cell cycle arrest and apoptosis and suggest a therapeutic application of RITA in HCC. - Abstract: Aberrant Notch signaling is observed in human hepatocellular carcinoma (HCC) and has been associated with the modulation of cell growth. However, the role of Notch signaling in HCC and its underlying mechanism remain elusive. RBP-J-interacting and tubulin-associated (RITA) mediates the nuclear export of RBP-J to tubulin fibers and downregulates Notch-mediated transcription. In this study, we found that RITA overexpression increased protein expression of p53 and Fbxw7 and downregulated the expression of cyclin D1, cyclin E, CDK2, Hes-1 and NF-κB p65. These changes led to growth inhibition and induced G0/G1 cell cycle arrest and apoptosis in SMMC7721 and HepG2 cells. Our findings indicate that RITA exerts tumor-suppressive effects in hepatocarcinogenesis through induction of G0/G1 cell cycle arrest and apoptosis and suggest a therapeutic application of RITA in HCC

Differential regulation of cyclin-dependent kinase inhibitors in neuroblastoma cells

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Qiao, Lan [Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Department of Pharmaceutical Sciences, Jilin University, Changchun 130021 (China); Paul, Pritha; Lee, Sora [Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Qiao, Jingbo [Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Wang, Yongsheng [Department of Pharmaceutical Sciences, Jilin University, Changchun 130021 (China); Chung, Dai H., E-mail: dai.chung@vanderbilt.edu [Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232 (United States)

2013-05-31

Highlights: •GRP-R signaling differentially regulated the expression of p21 and p27. •Silencing GRP/GRP-R downregulated p21, while p27 expression was upregulated. •Inhibition of GRP/GRP-R signaling enhanced PTEN expression, correlative to the increased expression of p27. •PTEN and p27 co-localized in cytoplasm and silencing PTEN decreased p27 expression. -- Abstract: Gastrin-releasing peptide (GRP) and its receptor (GRP-R) are highly expressed in undifferentiated neuroblastoma, and they play critical roles in oncogenesis. We previously reported that GRP activates the PI3K/AKT signaling pathway to promote DNA synthesis and cell cycle progression in neuroblastoma cells. Conversely, GRP-R silencing induces cell cycle arrest. Here, we speculated that GRP/GRP-R signaling induces neuroblastoma cell proliferation via regulation of cyclin-dependent kinase (CDK) inhibitors. Surprisingly, we found that GRP/GRP-R differentially induced expressions of p21 and p27. Silencing GRP/GRP-R decreased p21, but it increased p27 expressions in neuroblastoma cells. Furthermore, we found that the intracellular localization of p21 and p27 in the nuclear and cytoplasmic compartments, respectively. In addition, we found that GRP/GRP-R silencing increased the expression and accumulation of PTEN in the cytoplasm of neuroblastoma cells where it co-localized with p27, thus suggesting that p27 promotes the function of PTEN as a tumor suppressor by stabilizing PTEN in the cytoplasm. GRP/GRP-R regulation of CDK inhibitors and tumor suppressor PTEN may be critical for tumoriogenesis of neuroblastoma.

Differential regulation of cyclin-dependent kinase inhibitors in neuroblastoma cells

International Nuclear Information System (INIS)

Qiao, Lan; Paul, Pritha; Lee, Sora; Qiao, Jingbo; Wang, Yongsheng; Chung, Dai H.

2013-01-01

Highlights: •GRP-R signaling differentially regulated the expression of p21 and p27. •Silencing GRP/GRP-R downregulated p21, while p27 expression was upregulated. •Inhibition of GRP/GRP-R signaling enhanced PTEN expression, correlative to the increased expression of p27. •PTEN and p27 co-localized in cytoplasm and silencing PTEN decreased p27 expression. -- Abstract: Gastrin-releasing peptide (GRP) and its receptor (GRP-R) are highly expressed in undifferentiated neuroblastoma, and they play critical roles in oncogenesis. We previously reported that GRP activates the PI3K/AKT signaling pathway to promote DNA synthesis and cell cycle progression in neuroblastoma cells. Conversely, GRP-R silencing induces cell cycle arrest. Here, we speculated that GRP/GRP-R signaling induces neuroblastoma cell proliferation via regulation of cyclin-dependent kinase (CDK) inhibitors. Surprisingly, we found that GRP/GRP-R differentially induced expressions of p21 and p27. Silencing GRP/GRP-R decreased p21, but it increased p27 expressions in neuroblastoma cells. Furthermore, we found that the intracellular localization of p21 and p27 in the nuclear and cytoplasmic compartments, respectively. In addition, we found that GRP/GRP-R silencing increased the expression and accumulation of PTEN in the cytoplasm of neuroblastoma cells where it co-localized with p27, thus suggesting that p27 promotes the function of PTEN as a tumor suppressor by stabilizing PTEN in the cytoplasm. GRP/GRP-R regulation of CDK inhibitors and tumor suppressor PTEN may be critical for tumoriogenesis of neuroblastoma

The HTLV-1 Tax protein binding domain of cyclin-dependent kinase 4 (CDK4 includes the regulatory PSTAIRE helix

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Grassmann Ralph

2005-09-01

Full Text Available Abstract Background The Tax oncoprotein of human T-cell leukemia virus type 1 (HTLV-1 is leukemogenic in transgenic mice and induces permanent T-cell growth in vitro. It is found in active CDK holoenzyme complexes from adult T-cell leukemia-derived cultures and stimulates the G1- to-S phase transition by activating the cyclin-dependent kinase (CDK CDK4. The Tax protein directly and specifically interacts with CDK4 and cyclin D2 and binding is required for enhanced CDK4 kinase activity. The protein-protein contact between Tax and the components of the cyclin D/CDK complexes increases the association of CDK4 and its positive regulatory subunit cyclin D and renders the complex resistant to p21CIP inhibition. Tax mutants affecting the N-terminus cannot bind cyclin D and CDK4. Results To analyze, whether the N-terminus of Tax is capable of CDK4-binding, in vitro binding -, pull down -, and mammalian two-hybrid analyses were performed. These experiments revealed that a segment of 40 amino acids is sufficient to interact with CDK4 and cyclin D2. To define a Tax-binding domain and analyze how Tax influences the kinase activity, a series of CDK4 deletion mutants was tested. Different assays revealed two regions which upon deletion consistently result in reduced binding activity. These were isolated and subjected to mammalian two-hybrid analysis to test their potential to interact with the Tax N-terminus. These experiments concurrently revealed binding at the N- and C-terminus of CDK4. The N-terminal segment contains the PSTAIRE helix, which is known to control the access of substrate to the active cleft of CDK4 and thus the kinase activity. Conclusion Since the N- and C-terminus of CDK4 are neighboring in the predicted three-dimensional protein structure, it is conceivable that they comprise a single binding domain, which interacts with the Tax N-terminus.

Senescence and quiescence in adipose-derived stromal cells: Effects of human platelet lysate, fetal bovine serum and hypoxia.

Science.gov (United States)

Søndergaard, Rebekka Harary; Follin, Bjarke; Lund, Lisbeth Drozd; Juhl, Morten; Ekblond, Annette; Kastrup, Jens; Haack-Sørensen, Mandana

2017-01-01

Adipose-derived stromal cells (ASCs) are attractive sources for cell-based therapies. The hypoxic niche of ASCs in vivo implies that cells will benefit from hypoxia during in vitro expansion. Human platelet lysate (hPL) enhances ASC proliferation rates, compared with fetal bovine serum (FBS) at normoxia. However, the low proliferation rates of FBS-expanded ASCs could be signs of senescence or quiescence. We aimed to determine the effects of hypoxia and hPL on the expansion of ASCs and whether FBS-expanded ASCs are senescent or quiescent. ASCs expanded in FBS or hPL at normoxia or hypoxia until passage 7 (P7), or in FBS until P5 followed by culture in hPL until P7, were evaluated by proliferation rates, cell cycle analyses, gene expression and β-galactosidase activity. hPL at normoxia and hypoxia enhanced proliferation rates and expression of cyclins, and decreased G0/G1 fractions and expression of p21 and p27, compared with FBS. The shift from FBS to hPL enhanced cyclin levels, decreased p21 and p27 levels and tended to decrease G0/G1 fractions. Hypoxia does not add to the effect of hPL during ASC expansion with regard to proliferation, cell cycle regulation and expression of cyclins, p21 and p27. hPL rejuvenates FBS-expanded ASCs with regard to cell cycle regulation and expression of cyclins, p21 and p27. This indicates a reversible arrest. Therefore, we conclude that ASCs expanded until P7 are not senescent regardless of culture conditions. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Cyclin Y Is Involved in the Regulation of Adipogenesis and Lipid Production.

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Weiwei An

Full Text Available A new member of the cyclin family cyclin Y (CCNY is involved in the regulation of various physiological processes. In this study, the role of CCNY in energy metabolism was characterized. We found that compared with wild-type (WT mice, Ccny knockout (KO mice had both lower body weight and lower fat content. The Ccny KO mice also had a higher metabolic rate, resisted the stress of a high-fat diet, and were sensitive to calorie restriction. The expression levels of UCP1 and PGC1α were significantly higher in the brown adipose tissue (BAT of the Ccny KO mice than that of the WT littermate controls, whereas there was no significant difference in BAT weight between the WT and the Ccny KO mice. In addition, the down-regulation of Ccny resulted in suppression of white adipocyte differentiation both in vivo and in vitro, while the expression of Ccny was up-regulated by C/EBPα. Furthermore, both hepatocytes and HepG2 cells that were depleted of Ccny were insensitive to insulin stimulation, consistent with the significant inhibition of insulin sensitivity in the liver of the Ccny KO mice, but no significant changes in WAT and muscle, indicating that CCNY is involved in regulating the hepatic insulin signaling pathway. The hepatic insulin resistance generated by Ccny depletion resulted in down-regulation of the sterol-regulatory element-binding protein (SREBP1 and fatty acid synthase (FASN. Together, these results provide a new link between CCNY and lipid metabolism in mice, and suggest that inhibition of CCNY may offer a therapeutic approach to obesity and diabetes.

MLL5, a trithorax homolog, indirectly regulates H3K4 methylation, represses cyclin A2 expression, and promotes myogenic differentiation

Science.gov (United States)

Sebastian, Soji; Sreenivas, Prethish; Sambasivan, Ramkumar; Cheedipudi, Sirisha; Kandalla, Prashanth; Pavlath, Grace K.; Dhawan, Jyotsna

2009-01-01

Most cells in adult tissues are nondividing. In skeletal muscle, differentiated myofibers have exited the cell cycle permanently, whereas satellite stem cells withdraw transiently, returning to active proliferation to repair damaged myofibers. We have examined the epigenetic mechanisms operating in conditional quiescence by analyzing the function of a predicted chromatin regulator mixed lineage leukemia 5 (MLL5) in a culture model of reversible arrest. MLL5 is induced in quiescent myoblasts and regulates both the cell cycle and differentiation via a hierarchy of chromatin and transcriptional regulators. Knocking down MLL5 delays entry of quiescent myoblasts into S phase, but hastens S-phase completion. Cyclin A2 (CycA) mRNA is no longer restricted to S phase, but is induced throughout G0/G1, with activation of the cell cycle regulated element (CCRE) in the CycA promoter. Overexpressed MLL5 physically associates with the CCRE and impairs its activity. MLL5 also regulates CycA indirectly: Cux, an activator of CycA promoter and S phase is induced in RNAi cells, and Brm/Brg1, CCRE-binding repressors that promote differentiation are repressed. In knockdown cells, H3K4 methylation at the CCRE is reduced, reflecting quantitative global changes in methylation. MLL5 appears to lack intrinsic histone methyl transferase activity, but regulates expression of histone-modifying enzymes LSD1 and SET7/9, suggesting an indirect mechanism. Finally, expression of muscle regulators Pax7, Myf5, and myogenin is impaired in MLL5 knockdown cells, which are profoundly differentiation defective. Collectively, our results suggest that MLL5 plays an integral role in novel chromatin regulatory mechanisms that suppress inappropriate expression of S-phase-promoting genes and maintain expression of determination genes in quiescent cells. PMID:19264965

Regulation of the retinoblastoma protein-related p107 by G1 cyclin complexes

NARCIS (Netherlands)

Beijersbergen, R.L.; Carlée, L.; Kerkhoven, R.M.; Bernards, R.A.

1995-01-01

The orderly progression through the cell cycle is mediated by the sequential activation of several cyclin/cyclin-dependent kinase (cdk) complexes. These kinases phosphorylate a number of cellular substrates, among which is the product of the retinoblastoma gene, pRb. Phosphorylation of pRb in late

Phosphorylation of the Transient Receptor Potential Ankyrin 1 by Cyclin-dependent Kinase 5 affects Chemo-nociception

OpenAIRE

Hall, Bradford E.; Prochazkova, Michaela; Sapio, Matthew R.; Minetos, Paul; Kurochkina, Natalya; Binukumar, B. K.; Amin, Niranjana D.; Terse, Anita; Joseph, John; Raithel, Stephen J.; Mannes, Andrew J.; Pant, Harish C.; Chung, Man-Kyo; Iadarola, Michael J.; Kulkarni, Ashok B.

2018-01-01

Cyclin-dependent kinase 5 (Cdk5) is a key neuronal kinase that is upregulated during inflammation, and can subsequently modulate sensitivity to nociceptive stimuli. We conducted an in silico screen for Cdk5 phosphorylation sites within proteins whose expression was enriched in nociceptors and identified the chemo-responsive ion channel Transient Receptor Potential Ankyrin 1 (TRPA1) as a possible Cdk5 substrate. Immunoprecipitated full length TRPA1 was shown to be phosphorylated by Cdk5 and th...

Retroviruses Hijack Chromatin Loops to Drive Oncogene Expression and Highlight the Chromatin Architecture around Proto-Oncogenic Loci

Science.gov (United States)

Pattison, Jillian M.; Wright, Jason B.; Cole, Michael D.

2015-01-01

The majority of the genome consists of intergenic and non-coding DNA sequences shown to play a major role in different gene regulatory networks. However, the specific potency of these distal elements as well as how these regions exert function across large genomic distances remains unclear. To address these unresolved issues, we closely examined the chromatin architecture around proto-oncogenic loci in the mouse and human genomes to demonstrate a functional role for chromatin looping in distal gene regulation. Using cell culture models, we show that tumorigenic retroviral integration sites within the mouse genome occur near existing large chromatin loops and that this chromatin architecture is maintained within the human genome as well. Significantly, as mutagenesis screens are not feasible in humans, we demonstrate a way to leverage existing screens in mice to identify disease relevant human enhancers and expose novel disease mechanisms. For instance, we characterize the epigenetic landscape upstream of the human Cyclin D1 locus to find multiple distal interactions that contribute to the complex cis-regulation of this cell cycle gene. Furthermore, we characterize a novel distal interaction upstream of the Cyclin D1 gene which provides mechanistic evidence for the abundant overexpression of Cyclin D1 occurring in multiple myeloma cells harboring a pathogenic translocation event. Through use of mapped retroviral integrations and translocation breakpoints, our studies highlight the importance of chromatin looping in oncogene expression, elucidate the epigenetic mechanisms crucial for distal cis-regulation, and in one particular instance, explain how a translocation event drives tumorigenesis through upregulation of a proto-oncogene. PMID:25799187

Cyclin-like F-box protein plays a role in growth and development of the three model species Medicago truncatula, Lotus japonicus, and Arabidopsis thaliana

Directory of Open Access Journals (Sweden)

Boycheva I

2015-08-01

Full Text Available Irina Boycheva,1 Valya Vassileva,2 Miglena Revalska,1 Grigor Zehirov,2 Anelia Iantcheva1 1Department of Functional Genetics Legumes, 2AgroBioInstitute, Department of Plant Stress Molecular Biology, Institute of Plant Physiology and Genetics, Sofia, Bulgaria Abstract: In eukaryotes, F-box proteins are one of the main components of the SCF complex that belongs to the family of ubiquitin E3 ligases, which catalyze protein ubiquitination and maintain the balance between protein synthesis and degradation. In the present study, we clarified the role and function of the gene encoding cyclin-like F-box protein from Medicago truncatula using transgenic plants of the model species M. truncatula, Lotus japonicas, and Arabidopsis thaliana generated by Agrobacterium-mediated transformation. Morphological and transcriptional analyses combined with flow cytometry and histochemistry demonstrated the participation of this protein in many aspects of plant growth and development, including processes of indirect somatic embryogenesis and symbiotic nodulation. The cyclin-like F-box gene showed expression in all plant organs and tissues comprised of actively dividing cells. The observed variations in root and hypocotyl growth, leaf and silique development, ploidy levels, and leaf parameters in the obtained transgenic lines demonstrated the effects of this gene on organ development. Furthermore, knockdown of cyclin-like F-box led to accumulation of higher levels of the G2/M transition-specific gene cyclin B1:1 (CYCB1:1, suggesting its possible role in cell cycle control. Together, the collected data suggest a similar role of the cyclin-like F-box protein in the three model species, providing evidence for the functional conservation of the studied gene. Keywords: cyclin-like F-box, model legumes, Arabidopsis thaliana, plant growth, plant development, cell cycle

Copy Number Defects of G1-Cell Cycle Genes in Neuroblastoma are Frequent and Correlate with High Expression of E2F Target Genes and a Poor Prognosis

NARCIS (Netherlands)

Molenaar, Jan J.; Koster, Jan; Ebus, Marli E.; van Sluis, Peter; Westerhout, Ellen M.; de Preter, Katleen; Gisselsson, David; Øra, Ingrid; Speleman, Frank; Caron, Huib N.; Versteeg, Rogier

2012-01-01

The tightly controlled network of cell cycle genes consists of a core of cyclin dependent kinases (CDKs) that are activated by periodically expressed cyclins. The activity of the cyclin-CDK complexes is regulated by cyclin dependent kinase inhibitors (CDKIs) and multiple signal transduction routes

Piperlongumine decreases cell proliferation and the expression of cell cycle-associated proteins by inhibiting Akt pathway in human lung cancer cells.

Science.gov (United States)

Seok, Jin Sil; Jeong, Chang Hee; Petriello, Michael C; Seo, Han Geuk; Yoo, Hyunjin; Hong, Kwonho; Han, Sung Gu

2018-01-01

Piperlongumine (PL) is an alkaloid of a pepper plant found in Southeast Asia. PL is known to induce selective toxicity towards a variety of cancer cell types. To explore the possible anti-lung cancer effects of PL, A549 cells were treated with PL (0-40 μM) for 24 h. Alterations in the expression of cell cycle-associated proteins (cyclin D1, cyclin-dependent kinase 4 (CDK4), CDK6 and retinoblastoma (Rb)) and intracellular signaling molecules (extracellular signal receptor-activated kinase 1/2 (ERK1/2), Akt, p38 and nuclear factor-κB (NF-κB)) were examined in cells following treatment of PL using Western blot analysis. Results showed that proliferation of cells were significantly decreased by PL in a dose-dependent manner. Flow cytometry results demonstrated increased number of cells in G1 phase in PL (40 μM)-treated group. Reactive oxygen species was significantly increased in cells treated with PL at 20-40 μM. The expression of cyclin D1, CDK4, CDK6 and p-Rb were markedly decreased in cells treated with PL at 40 μM. Treatment of cells with PL suppressed phosphorylation of Akt but increased ERK1/2 phosphorylation. Treatment of PL significantly decreased nuclear translocation of NF-κB p65 in cells. These results suggest that PL possesses antiproliferative properties in A549 cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

microRNA-365, down-regulated in colon cancer, inhibits cell cycle progression and promotes apoptosis of colon cancer cells by probably targeting Cyclin D1 and Bcl-2.

Science.gov (United States)

Nie, Jing; Liu, Lin; Zheng, Wei; Chen, Lin; Wu, Xin; Xu, Yingxin; Du, Xiaohui; Han, Weidong

2012-01-01

Deregulated microRNAs participate in carcinogenesis and cancer progression, but their roles in cancer development remain unclear. In this study, miR-365 expression was found to be downregulated in human colon cancer tissues as compared with that in matched non-neoplastic mucosa tissues, and its downregulation was correlated with cancer progression and poor survival in colon cancer patients. Functional studies revealed that restoration of miR-365 expression inhibited cell cycle progression, promoted 5-fluorouracil-induced apoptosis and repressed tumorigenicity in colon cancer cell lines. Furthermore, bioinformatic prediction and experimental validation were used to identify miR-365 target genes and indicated that the antitumor effects of miR-365 were probably mediated by its targeting and repression of Cyclin D1 and Bcl-2 expression, thus inhibiting cell cycle progression and promoting apoptosis. These results suggest that downregulation of miR-365 in colon cancer may have potential applications in prognosis prediction and gene therapy in colon cancer patients.

Knockdown of stat3 expression by RNAi inhibits in vitro growth of human ovarian cancer

International Nuclear Information System (INIS)

Zhao, Shu-Hua; Zhao, Fan; Zheng, Jing-Ying; Gao, Li-Fang; Zhao, Xue-Jian; Cui, Man-Hua

2011-01-01

The aim of the study was to investigate the suppressive effects of pSilencer2.1-U6-siRNA-stat3 recombinant plasmids on the growth of ovarian cancer in vitro. Three pairs of DNA template (stat3-1, stat3-2, stat3-3) specific for different target sites on stat3 mRNA were synthesized to reconstruct pSilencer2.1-U6-siRNA-stat3s, which were transfected into SKOV3 cells. The expressions of STAT3, BcL-2, cyclin D1 and C-myc in these cells were detected by Western blot and Northern blot. The cell cycle and the growth were determined by flow cytometry (FCM) and MTT assay, respectively. Cell apoptosis was determined by TUNEL staining. Of the three siRNAs, only siRNA targeting stat3-3 markedly suppressed the protein expression of stat3 in SKOV3 cells; MTT assay and FCM showed that transfection of stat3-3 siRNA could significantly suppress the growth of SKOV3 cells and arrest the cell cycle in vitro. TUNEL staining also showed massive apoptosis in SKOV3 cells transfected with stat3-3 siRNA. pSilencer2.1-U6-siRNA-stat3-3 can significantly inhibit the STAT3 expression in human ovarian cancer cells resulting in the inhibition of the cancer growth and the increase of apoptosis of cancer cells

Baicalein induces G1 arrest in oral cancer cells by enhancing the degradation of cyclin D1 and activating AhR to decrease Rb phosphorylation

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Cheng, Ya-Hsin, E-mail: yhcheng@mail.cmu.edu.tw [Department of Physiology, School of Medicine, China Medical University, Taichung 40402, Taiwan, ROC (China); Li, Lih-Ann; Lin, Pinpin; Cheng, Li-Chuan [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Miaoli 35053, Taiwan, ROC (China); Hung, Chein-Hui [Graduate Institute of Clinical Medicine Sciences, Chang Gung University, Puizi City, Chiayi 613, Taiwan, ROC (China); Chang, Nai Wen [Department of Biochemistry, School of Medicine, China Medical University, Taichung, Taiwan, ROC (China); Lin, Chingju [Department of Physiology, School of Medicine, China Medical University, Taichung 40402, Taiwan, ROC (China)

2012-09-15

Baicalein is a flavonoid, known to have anti-inflammatory and anti-cancer effects. As an aryl hydrocarbon receptor (AhR) ligand, baicalein at high concentrations blocks AhR-mediated dioxin toxicity. Because AhR had been reported to play a role in regulating the cell cycle, we suspected that the anti-cancer effect of baicalein is associated with AhR. This study investigated the molecular mechanism involved in the anti-cancer effect of baicalein in oral cancer cells HSC-3, including whether such effect would be AhR-mediated. Results revealed that baicalein inhibited cell proliferation and increased AhR activity in a dose-dependent manner. Cell cycle was arrested at the G1 phase and the expression of CDK4, cyclin D1, and phosphorylated retinoblastoma (pRb) was decreased. When the AhR was suppressed by siRNA, the reduction of pRb was partially reversed, accompanied by a decrease of cell population at G1 phase and an increase at S phase, while the reduction of cyclin D1 and CDK4 did not change. This finding suggests that the baicalein activation of AhR is indeed associated with the reduction of pRb, but is independent of the reduction of cyclin D1 and CDK4. When cells were pre-treated with LiCl, the inhibitor of GSK-3β, the decrease of cyclin D1 was blocked and the reduction of pRb was recovered. The data indicates that in HSC-3 the reduction of pRb is both mediated by baicalein through activation of AhR and facilitation of cyclin D1 degradation, which causes cell cycle arrest at the G1 phase, and results in the inhibition of cell proliferation. -- Highlights: ► Baicalein causes the G1 phase arrest by decreasing Rb phosphorylation. ► Baicalein modulates AhR-mediated cell proliferation. ► Both AhR activation and cyclin D1 degradation results in hypophosphorylation of Rb. ► Baicalein facilitates cyclin D1 degradation by signalling the GSK-3β pathway.

Perfusion of veins at arterial pressure increases the expression of KLF5 and cell cycle genes in smooth muscle cells

International Nuclear Information System (INIS)

Amirak, Emre; Zakkar, Mustafa; Evans, Paul C.; Kemp, Paul R.

2010-01-01

Vascular smooth muscle cell (VSMC) proliferation remains a major cause of veno-arterial graft failure. We hypothesised that exposure of venous SMCs to arterial pressure would increase KLF5 expression and that of cell cycle genes. Porcine jugular veins were perfused at arterial or venous pressure in the absence of growth factors. The KLF5, c-myc, cyclin-D and cyclin-E expression were elevated within 24 h of perfusion at arterial pressure but not at venous pressure. Arterial pressure also reduced the decline in SM-myosin heavy chain expression. These data suggest a role for KLF5 in initiating venous SMCs proliferation in response to arterial pressure.

Toll-like receptor 7 regulates pancreatic carcinogenesis in mice and humans

Science.gov (United States)

Ochi, Atsuo; Graffeo, Christopher S.; Zambirinis, Constantinos P.; Rehman, Adeel; Hackman, Michael; Fallon, Nina; Barilla, Rocky M.; Henning, Justin R.; Jamal, Mohsin; Rao, Raghavendra; Greco, Stephanie; Deutsch, Michael; Medina-Zea, Marco V.; Saeed, Usama Bin; Ego-Osuala, Melvin O.; Hajdu, Cristina; Miller, George

2012-01-01

Pancreatic ductal adenocarcinoma is an aggressive cancer that interacts with stromal cells to produce a highly inflammatory tumor microenvironment that promotes tumor growth and invasiveness. The precise interplay between tumor and stroma remains poorly understood. TLRs mediate interactions between environmental stimuli and innate immunity and trigger proinflammatory signaling cascades. Our finding that TLR7 expression is upregulated in both epithelial and stromal compartments in human and murine pancreatic cancer led us to postulate that carcinogenesis is dependent on TLR7 signaling. In a mouse model of pancreatic cancer, TLR7 ligation vigorously accelerated tumor progression and induced loss of expression of PTEN, p16, and cyclin D1 and upregulation of p21, p27, p53, c-Myc, SHPTP1, TGF-β, PPARγ, and cyclin B1. Furthermore, TLR7 ligation induced STAT3 activation and interfaced with Notch as well as canonical NF-κB and MAP kinase pathways, but downregulated expression of Notch target genes. Moreover, blockade of TLR7 protected against carcinogenesis. Since pancreatic tumorigenesis requires stromal expansion, we proposed that TLR7 ligation modulates pancreatic cancer by driving stromal inflammation. Accordingly, we found that mice lacking TLR7 exclusively within their inflammatory cells were protected from neoplasia. These data suggest that targeting TLR7 holds promise for treatment of human pancreatic cancer. PMID:23023703

A phase i study of the cyclin-dependent kinase 4/6 inhibitor ribociclib (LEE011) in patients with advanced solid tumors and lymphomas

NARCIS (Netherlands)

Infante, Jeffrey R.; Cassier, Philippe A.; Gerecitano, John F.; Witteveen, Petronella O.; Chugh, Rashmi; Ribrag, Vincent; Chakraborty, Abhijit; Matano, Alessandro; Dobson, Jason R.; Crystal, Adam S.; Parasuraman, Sudha; Shapiro, Geoffrey I.

2016-01-01

Purpose: Ribociclib (an oral, highly specific cyclin-dependent kinase 4/6 inhibitor) inhibits tumor growth in preclinical models with intact retinoblastoma protein (Rb+). This first-in-human study investigated the MTD, recommended dose for expansion (RDE), safety, preliminary activity,

Antitumor Effects of Flavopiridol on Human Uterine Leiomyoma In Vitro and in a Xenograft Model

Science.gov (United States)

Lee, Hyun-Gyo; Baek, Jong-Woo; Shin, So-Jin; Kwon, Sang-Hoon; Cha, Soon-Do; Park, Won-Jin; Chung, Rosa; Choi, Eun-Som; Lee, Gun-Ho

2014-01-01

Dysregulated cyclin-dependent kinases (CDKs) are considered a potential target for cancer therapy. Flavopiridol is a potent CDK inhibitor. In this study, the antiproliferative effect of the flavonoid compound flavopiridol and its mechanism in human uterine leiomyoma cells were investigated. The present study focused on the effect of flavopiridol in cell proliferation and cell cycle progression in primary cultured human uterine leiomyoma cells. Cell viability and cell proliferation assays were conducted. Flow cytometry was performed to determine the effect of flavopiridol on cell cycle. The expression of cell cycle regulatory-related proteins was evaluated by Western blotting. Cell viability and proliferation of uterine leiomyoma cells were significantly reduced by flavopiridol treatment in a dose-dependent manner. Flow cytometry results showed that flavopiridol induced G1 phase arrest. Flavopiridol-induced growth inhibition in uterine leiomyoma cells was associated with increased expression of p21cip/wafl and p27kip1 in a dose-dependent manner. Downregulation of CDK2/4 and Cyclin A with a concomitant increase in dephosphorylation of retinoblastoma was observed. This study demonstrates that flavopiridol inhibits cell proliferation by initiating G1 cell cycle arrest in human uterine leiomyoma. We also found that flavopiridol is effective in inhibiting xenografted human uterine leiomyoma growth. These results indicate that flavopiridol could prove to be a promising chemopreventive and therapeutic agent for human uterine leiomyoma. PMID:24572052

miR-24 and miR-205 expression is dependent on HPV onco-protein expression in keratinocytes

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McKenna, Declan J., E-mail: dj.mckenna@ulster.ac.uk [Biomedical Sciences Research Institute, University of Ulster, Coleraine, Co. Derry BT52 1SA (United Kingdom); Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen' s University Belfast, Belfast BT9 7BL (United Kingdom); Patel, Daksha, E-mail: d.patel@qub.ac.uk [Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen' s University Belfast, Belfast BT9 7BL (United Kingdom); McCance, Dennis J., E-mail: d.mccance@qub.ac.uk [Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Science, Queen' s University Belfast, Belfast BT9 7BL (United Kingdom)

2014-01-05

A screen of microRNA (miRNA) expression following differentiation in human foreskin keratinocytes (HFKs) identified changes in several miRNAs, including miR-24 and miR-205. We investigated how expression of Human Papilloma Virus Type-16 (HPV16) onco-proteins E6 and E7 affected expression of miR-24 and miR-205 during proliferation and differentiation of HFKs. We show that the induction of both miR-24 and miR-205 observed during differentiation of HFKs is lost in HFKs expressing E6 and E7. We demonstrate that the effect on miR-205 is due to E7 activity, as miR-205 expression is dependent on pRb expression. Finally, we provide evidence that miR-24 effects in the cell may be due to targeting of cyclin dependent kinase inhibitor p27. In summary, these results indicate that expression of both miR-24 and miR-205 are impacted by E6 and/or E7 expression, which may be one mechanism by which HPV onco-proteins can disrupt the balance between proliferation and differentiation in keratinocytes. - Highlights: • miR-24 and miR-205 are induced during keratinocyte differentiation. • This induction is lost in keratinocytes expressing HPV onco-proteins E6 and E7. • miR-205 is dependent upon pRb expression. • miR-24 targets p27 in cycling keratinocytes.

miR-24 and miR-205 expression is dependent on HPV onco-protein expression in keratinocytes

International Nuclear Information System (INIS)

McKenna, Declan J.; Patel, Daksha; McCance, Dennis J.

2014-01-01

A screen of microRNA (miRNA) expression following differentiation in human foreskin keratinocytes (HFKs) identified changes in several miRNAs, including miR-24 and miR-205. We investigated how expression of Human Papilloma Virus Type-16 (HPV16) onco-proteins E6 and E7 affected expression of miR-24 and miR-205 during proliferation and differentiation of HFKs. We show that the induction of both miR-24 and miR-205 observed during differentiation of HFKs is lost in HFKs expressing E6 and E7. We demonstrate that the effect on miR-205 is due to E7 activity, as miR-205 expression is dependent on pRb expression. Finally, we provide evidence that miR-24 effects in the cell may be due to targeting of cyclin dependent kinase inhibitor p27. In summary, these results indicate that expression of both miR-24 and miR-205 are impacted by E6 and/or E7 expression, which may be one mechanism by which HPV onco-proteins can disrupt the balance between proliferation and differentiation in keratinocytes. - Highlights: • miR-24 and miR-205 are induced during keratinocyte differentiation. • This induction is lost in keratinocytes expressing HPV onco-proteins E6 and E7. • miR-205 is dependent upon pRb expression. • miR-24 targets p27 in cycling keratinocytes

Effect of increased HoxB4 on human megakaryocytic development

International Nuclear Information System (INIS)

Zhong, Yiming; Sullenbarger, Brent; Lasky, Larry C.

2010-01-01

Research highlights: → HoxB4 overexpression in human TF1 cells increased the expression of CD61 and CD41a. → HoxB4 fusion protein enhanced megakaryocytic development of CD34 + cord blood cells. → Ectopic HoxB4 increased Tpo receptor expression and decreased c-Myb expression. → HoxB4 RNA silencing increased c-Myb expression and decreased Fli-1 expression. -- Abstract: In order to produce clinically useful quantities of platelets ex vivo we may need to firstly enhance early self-renewal of hematopoietic stem cells (HSCs) and/or megakaryocyte (Mk) progenitors. The homeodomain transcription factor HoxB4 has been shown to be an important regulator of stem cell renewal and hematopoiesis; however, its effect on megakaryopoiesis is unclear. In this study, we investigated the effect of HoxB4 overexpression or RNA silencing on megakaryocytic development in the human TF1 progenitor cell line; we then used recombinant tPTD-HoxB4 fusion protein to study the effect of exogenous HoxB4 on megakaryocytic development of human CD34 positively-selected cord blood cells. We found that ectopic HoxB4 in TF1 cells increased the antigen expression of CD61and CD41a, increased the gene expression of thrombopoietin receptor (TpoR), Scl-1, Cyclin D1, Fog-1 and Fli-1 while it decreased c-Myb expression. HoxB4 RNA silencing in TF1 cells decreased the expression of CD61 and CD41a and decreased Fli-1 expression while it increased the expression of c-Myb. Recombinant tPTD-HoxB4 fusion protein increased the percentages and absolute numbers of CD41a and CD61 positive cells during megakaryocytic differentiation of CD34 positively-selected cord blood cells and increased the numbers of colony-forming unit-megakaryocyte (CFU-Mk). Adding tPTD-HoxB4 fusion protein increased the gene expression of TpoR, Cyclin D1, Fog-1 and Fli-1 while it inhibited c-Myb expression. Our data suggest that increased HoxB4 enhanced early megakaryocytic development in human TF1 cells and CD34 positively-selected cord

Effect of increased HoxB4 on human megakaryocytic development

Energy Technology Data Exchange (ETDEWEB)

Zhong, Yiming [Department of Pathology, The Ohio State University, Columbus, OH (United States); Program in Molecular, Cellular, and Developmental Biology, The Ohio State University, Columbus, OH (United States); Sullenbarger, Brent [Department of Pathology, The Ohio State University, Columbus, OH (United States); Lasky, Larry C., E-mail: Lasky.4@osu.edu [Department of Pathology, The Ohio State University, Columbus, OH (United States); Program in Molecular, Cellular, and Developmental Biology, The Ohio State University, Columbus, OH (United States)

2010-07-30

Research highlights: {yields} HoxB4 overexpression in human TF1 cells increased the expression of CD61 and CD41a. {yields} HoxB4 fusion protein enhanced megakaryocytic development of CD34{sup +} cord blood cells. {yields} Ectopic HoxB4 increased Tpo receptor expression and decreased c-Myb expression. {yields} HoxB4 RNA silencing increased c-Myb expression and decreased Fli-1 expression. -- Abstract: In order to produce clinically useful quantities of platelets ex vivo we may need to firstly enhance early self-renewal of hematopoietic stem cells (HSCs) and/or megakaryocyte (Mk) progenitors. The homeodomain transcription factor HoxB4 has been shown to be an important regulator of stem cell renewal and hematopoiesis; however, its effect on megakaryopoiesis is unclear. In this study, we investigated the effect of HoxB4 overexpression or RNA silencing on megakaryocytic development in the human TF1 progenitor cell line; we then used recombinant tPTD-HoxB4 fusion protein to study the effect of exogenous HoxB4 on megakaryocytic development of human CD34 positively-selected cord blood cells. We found that ectopic HoxB4 in TF1 cells increased the antigen expression of CD61and CD41a, increased the gene expression of thrombopoietin receptor (TpoR), Scl-1, Cyclin D1, Fog-1 and Fli-1 while it decreased c-Myb expression. HoxB4 RNA silencing in TF1 cells decreased the expression of CD61 and CD41a and decreased Fli-1 expression while it increased the expression of c-Myb. Recombinant tPTD-HoxB4 fusion protein increased the percentages and absolute numbers of CD41a and CD61 positive cells during megakaryocytic differentiation of CD34 positively-selected cord blood cells and increased the numbers of colony-forming unit-megakaryocyte (CFU-Mk). Adding tPTD-HoxB4 fusion protein increased the gene expression of TpoR, Cyclin D1, Fog-1 and Fli-1 while it inhibited c-Myb expression. Our data suggest that increased HoxB4 enhanced early megakaryocytic development in human TF1 cells and CD34

Inhibition of proliferation and differentiation and promotion of apoptosis by cyclin L2 in mouse embryonic carcinoma P19 cells

International Nuclear Information System (INIS)

Zhuo, Lili; Gong, Jie; Yang, Rong; Sheng, Yanhui; Zhou, Lei; Kong, Xiangqing; Cao, Kejiang

2009-01-01

Cyclin L2 (CCNL2) is a novel member of the cyclin gene family. In a previous study, we demonstrated that CCNL2 expression was upregulated in ventricular septum tissues from patients with ventricular septal defect compared to healthy controls. In the present study, we established a stable CCNL2-overexpressing P19 cell line that can differentiate to myocardial cells when treated with 1% dimethyl sulfoxide (DMSO). Our data showed that stable CCNL2-overexpressing P19 cells were less differentiated after treatment with 1% DMSO and that expression of myocardial cell differentiation-related genes (such as cardiac actin, GATA4, Mef2C, Nkx2.5, and BNP) were reduced compared to vector-only transfected P19. Moreover, P19 cells overexpressing the CCNL2 gene had a reduced growth rate and a remarkably decreased S phase. We also found that these cells underwent apoptosis, as detected by two different apoptosis assays. The anti-apoptotic Bcl-2 protein was also downregulated in these cells. In addition, real-time PCR analysis revealed that expression of Wnt and β-catenin was suppressed and GSK3β was induced in the CCNL2-overexpressing P19 cells. These data suggest that overexpression of CCNL2 inhibited proliferation and differentiation of mouse embryonic carcinoma P19 cells and induced them to undergo apoptosis, possibly through the Wnt signal transduction pathway.

Roles of human papillomavirus infection and stathmin in the pathogenesis of sinonasal inverted papilloma.

Science.gov (United States)

Lin, Hai; Lin, Dong; Xiong, Xi-Sheng

2016-02-01

The purpose of this study was to investigate roles of human papillomavirus (HPV) infection and stathmin in sinonasal inverted papilloma (SNIP). HPV DNA detection was performed by the fluorescence-based polymerase chain reaction (PCR) method. Stathmin protein expression was investigated by the immunohistochemistry method and mRNA expression of stathmin, Kif2a, and cyclin D1 were assessed by real-time PCR in SNIP and control subjects. The positive rate of HPV DNA detected in SNIP was about 53.6% (15 of 28). Recurrent cases showed a higher rate of HPV infection compared with initial cases and higher Krouse stage (T3 + T4) cases showed higher rate of HPV infection than lower Krouse stage (T1 + T2) cases. Stronger expression of stathmin, Kif2a, and cyclin D1 were observed in SNIP, especially HPV(+) SNIP. HPV infection was closely associated with recurrence and progression of SNIP. Stathmin is a valuable prognostic marker and could be considered as a therapeutic target in patients with SNIP. © 2015 Wiley Periodicals, Inc.

Increased arylhydrocarbon receptor expression offers a potential therapeutic target for pancreatic cancer.

Science.gov (United States)

Koliopanos, Alexander; Kleeff, Jörg; Xiao, Yi; Safe, Stephen; Zimmermann, Arthur; Büchler, Markus W; Friess, Helmut

2002-09-05

The arylhydrocarbon receptor (AhR) was initially identified as a member of the adaptive metabolic and toxic response pathway to polycyclic aromatic hydrocarbons and to halogenated dibenzo-p-dioxins and dibenzofurans. In the present study, we sought to determine the functional significance of the AhR pathway in pancreatic carcinogenesis. AhR expression was analysed by Northern blotting. The exact site of AhR expression was analysed by in situ hybridization and immunohistochemistry. The effects of TCDD and four selective AhR agonists on pancreatic cancer cell lines were investigated by growth assays, apoptosis assays, and induction of the cyclin-dependent kinase inhibitor p21. There was strong AhR mRNA expression in 14 out of 15 pancreatic cancer samples, weak expression in chronic pancreatitis tissues, and faint expression in all normal pancreata. In pancreatic cancer tissues, AhR mRNA and protein expression were localized in the cytoplasm of pancreatic cancer cells. TCDD and the four AhR agonists inhibited pancreatic cancer cell growth in a dose-dependent manner, and decreased anchorage-independent cell growth. DAPI staining did not reveal nuclear fragmentation and CYP1A1 and was not induced by TCDD and AhR agonists. In contrast, TCDD and AhR agonists induced the expression of the cyclin-dependent kinase inhibitor p21. In conclusion, the relatively non-toxic AhR agonists caused growth inhibition in pancreatic cancer cells with high AhR expression levels via cell cycle arrest. In addition, almost all human pancreatic cancer tissues expressed this receptor at high levels, suggesting that these or related compounds may play a role in the therapy of pancreatic cancer in the future.

Nascent histamine induces α-synuclein and caspase-3 on human cells

Energy Technology Data Exchange (ETDEWEB)

Caro-Astorga, Joaquín; Fajardo, Ignacio; Ruiz-Pérez, María Victoria; Sánchez-Jiménez, Francisca; Urdiales, José Luis, E-mail: jlurdial@uma.es

2014-09-05

Highlights: • Nascent histamine alters cyclin expression pattern. • Nascent histamine increases expression of α-synuclein. • Nascent histamine activates caspase-3. - Abstract: Histamine (Hia) is the most multifunctional biogenic amine. It is synthetized by histidine decarboxylase (HDC) in a reduced set of mammalian cell types. Mast cells and histaminergic neurons store Hia in specialized organelles until the amine is extruded by exocytosis; however, other immune and cancer cells are able to produce but not store Hia. The intracellular effects of Hia are still not well characterized, in spite of its physiopathological relevance. Multiple functional relationships exist among Hia metabolism/signaling elements and those of other biogenic amines, including growth-related polyamines. Previously, we obtained the first insights for an inhibitory effect of newly synthetized Hia on both growth-related polyamine biosynthesis and cell cycle progression of non-fully differentiated mammalian cells. In this work, we describe progress in this line. HEK293 cells were transfected to express active and inactive versions of GFP-human HDC fusion proteins and, after cell sorting by flow cytometry, the relative expression of a large number of proteins associated with cell signaling were measured using an antibody microarray. Experimental results were analyzed in terms of protein–protein and functional interaction networks. Expression of active HDC induced a cell cycle arrest through the alteration of the levels of several proteins such as cyclin D1, cdk6, cdk7 and cyclin A. Regulation of α-synuclein and caspase-3 was also observed. The analyses provide new clues on the molecular mechanisms underlying the regulatory effects of intracellular newly synthetized Hia on cell proliferation/survival, cell trafficking and protein turnover. This information is especially interesting for emergent and orphan immune and neuroinflammatory diseases.

Skeletal Muscle Estrogen Receptor Activation in Response to Eccentric Exercise Up-Regulates Myogenic-Related Gene Expression Independent of Differing Serum Estradiol Levels Occurring during the Human Menstrual Cycle.

Science.gov (United States)

Haines, Mackenzie; McKinley-Barnard, Sarah K; Andre, Thomas L; Gann, Josh J; Hwang, Paul S; Willoughby, Darryn S

2018-03-01

This study sought to determine if the differences in serum estradiol we have previously observed to occur during the mid-follicular (MF) and mid-luteal (ML) phases of the female menstrual cycle could be attributed to estrogen-induced receptor activation and subsequent effects on myogenic-related genes which may otherwise impact muscle regeneration in response to eccentric exercise. Twenty-two physically-active females (20.9 ± 1.4 years, 63.5 ± 9.0 kg, 1.65 ± 0.08 m) underwent an eccentric exercise bout of the knee extensors during the MF and ML phases of their 28-day menstrual cycle. Prior to (PRE), at 6 (6HRPOST), and 24 (24HRPOST) hours post-exercise for each session, participants had muscle biopsies obtained. Skeletal muscle estradiol and estrogen receptor-α (ER-α) content and ER-DNA binding were determined with ELISA. Real-time PCR was used to assess ER-α, Myo-D, and cyclin D1 mRNA expression. Data were analyzed utilizing a 2 x 3 repeated measures univariate analyses of variance (ANOVA) for each criterion variable (p ≤ .05). Skeletal muscle estradiol levels were not significantly impacted by either menstrual phase (p > 0.05); however, both ER-α mRNA and protein were significantly increased during MF (p < 0.05). ER-DNA binding and Myo-D mRNA expression increased significantly in both menstrual phases in response to exercise but were not different from one another; however, cyclin D1 mRNA expression was significantly greater during MF. This study demonstrates that skeletal muscle ER-α activation in response to eccentric exercise up-regulates myogenic-related gene expression independent of serum estradiol levels occurring during the human menstrual cycle.

Cyclin D1 and p22ack1 play opposite roles in plant growth and development

International Nuclear Information System (INIS)

Cho, Jeong Woo; Park, Sun Chung; Shin, Eun Ah; Kim, Chong Ki; Han, Woong; Sohn, Soo-In; Song, Pill Soon; Wang, Myeong Hyeon

2004-01-01

The plant cell division cycle, a highly coordinated process, is continually regulated during the growth and development of plants. In this report, we demonstrate how two cell-cycle regulators act together to control cell proliferation in transgenic Arabidopsis. To identify potential cyclin dependent kinase regulators from Arabidopsis, we employed an two-hybrid screening system to isolate genes encoding G1 specific cyclin-interacting proteins. One of these, p22 ack1 , which encodes a novel 22 kDa protein, binds to cyclin D1. Overexpression of p22 ack1 in transgenic Arabidopsis resulted in growth retardation due to a strong inhibition of cell division in the leaf primordial and meristematic tissue. The leaf shape of p22 ack1 transgenic Arabidopsis was altered from oval in wild-type to dentate. Wild-type phenotype was successfully restored in F1 hybrids by cross-hybridizing the p22 ackl Arabidopsis mutants with cyclin D1. Taken together, these results suggest that p22 ack1 and cyclin D1, which act antagonistically, are major rate-limiting factors for cell division in the leaf meristem

Altered expression of the cell cycle regulatory protein cyclin D1 in the rat dentate gyrus after adrenalectomy-induced granular cell lass

NARCIS (Netherlands)

Postigo, JA; Van der Werf, YD; Korf, J; Krugers, HJ

1998-01-01

The loss of dentate gyrus (DG) granular cells after removal of the rat adrenal glands (ADX) is mediated by a process that is apoptotic in nature. The present study was initiated to compare changes in the immunocytochemical distribution of the cell-cycle regulatory protein cyclin D1, which has been

Altered gene expression in human placentas after IVF/ICSI.

Science.gov (United States)

Nelissen, Ewka C M; Dumoulin, John C M; Busato, Florence; Ponger, Loïc; Eijssen, Lars M; Evers, Johannes L H; Tost, Jörg; van Montfoort, Aafke P A

2014-12-01

Is gene expression in placental tissue of IVF/ICSI patients altered when compared with a spontaneously conceived group, and are these alterations due to loss of imprinting (LOI) in the case of imprinted genes? An altered imprinted gene expression of H19 and Pleckstrin homology-like domain family A member 2 (PHLDA2), which was not due to LOI, was observed in human placentas after IVF/ICSI and several biological pathways were significantly overrepresented and mostly up-regulated. Genomic imprinting plays an important role in placental biology and in placental adaptive responses triggered by external stimuli. Changes in placental development and function can have dramatic effects on the fetus and its ability to cope with the intrauterine environment. An increased frequency of placenta-related problems as well as an adverse perinatal outcome is seen in IVF/ICSI derived pregnancies, but the role of placental epigenetic deregulation is not clear yet. In this prospective cohort study, a total of 115 IVF/ICSI and 138 control couples were included during pregnancy. After applying several exclusion criteria (i.e. preterm birth or stillbirth, no placental samples, pregnancy complications or birth defects), respectively, 81 and 105 placentas from IVF/ICSI and control pregnancies remained for analysis. Saliva samples were collected from both parents. We quantitatively analysed the mRNA expression of several growth-related imprinted genes [H19, insulin-like growth factor 2 (IGF2), PHLDA2, cyclin-dependent kinase inhibitor 1C (CDKN1C), mesoderm-specific transcript homolog (MEST) isoform α and β by quantitative PCR] after standardization against three housekeeping genes [Succinate dehydrogenase A (SDHA), YWHAZ and TATA-binding protein (TBP)]. A quantitative allele-specific expression analysis of the differentially expressed imprinted genes was performed to investigate LOI, independent of the mechanism of imprinting. Furthermore, a microarray analysis was carried out (n = 10 in

Effect of Flavopiridol on Radiation-induced Apoptosis of Human Laryngeal and Lung Cancer Cells

International Nuclear Information System (INIS)

Kim, Suzy; Kwon, Eun Kyung; Lee, B. S.; Lee, Seung Hee; Park, B. S.; Wu, Hong Gyun

2007-01-01

Purpose: To investigate the flavopiridol effect on radiation-induced apoptosis and expression of apoptosisrelated genes of human laryngeal and lung cancer cells. Materials and Methods: A human laryngeal cancer cell line, AMC-HN3 and a human lung cancer cell line, NCI-H460, were used in the study. The cells were divided into four groups according to the type of treatment: 1) control groups; 2) cells that were only irradiated; 3) cells treated only with flavopiridol; 4) cells treated with flavopiridol and radiation simultaneously. The cells were irradiated with 10 Gy of X-rays using a 4 MV linear accelerator. Flavopiridol was administered to the media at a concentration of 100 nM for 24 hours. We compared the fraction of apoptotic cells of each group 24 hours after the initiation of treatment. The fraction of apoptotic cells was detected by measurement of the sub-G1 fractions from a flow cytometric analysis. The expression of apoptosis-regulating genes, including cleaved caspase-3, cleaved PARP (poly (ADP-ribose) polymerase), p53, p21, cyclin D1, and phosphorylated Akt (protein kinase B) were analyzed by Western blotting. Results: The sub-G1 fraction of cells was significantly increased in the combination treatment group, as compared to cells exposed to radiation alone or flavopiridol alone. Western blotting also showed an increased expression of cleaved caspase-3 and cleaved PARP expression in cells of the combination treatment group, as compared with cells exposed to radiation alone or flavopiridol alone. Treatment with flavopiridol down regulated cyclin D1 expression of both cell lines but its effect on p53 and p21 expression was different according to each individual cell line. Flavopiridol did not affect the expression of phophorylated Akt in both cell lines. Conclusion: Treatment with flavopiridol increased radiation-induced apoptosis of both the human laryngeal and lung cancer cell lines. Flavopiridol effects on p53 and p21 expression were different according

Functional Role of Cyclin-Dependent Kinase 5 in the Regulation of Melanogenesis and Epidermal Structure.

Science.gov (United States)

Dong, Changsheng; Yang, Shanshan; Fan, Ruiwen; Ji, Kaiyuan; Zhang, Junzhen; Liu, Xuexian; Hu, Shuaipeng; Xie, Jianshan; Liu, Yu; Gao, Wenjun; Wang, Haidong; Yao, Jianbo; Smith, George W; Herrid, Muren

2017-10-23

The mammalian integumentary system plays important roles in body homeostasis, and dysfunction of melanogenesis or epidermal development may lead to a variety of skin diseases, including melanoma. Skin pigmentation in humans and coat color in fleece-producing animals are regulated by many genes. Among them, microphthalmia-associated transcription factor (MITF) and paired-box 3 (PAX3) are at the top of the cascade and regulate activities of many important melanogenic enzymes. Here, we report for the first time that cyclin-dependent kinase 5 (Cdk5) is an essential regulator of MITF and PAX3. Cdk5 knockdown in mice causes a lightened coat color, a polarized distribution of melanin and hyperproliferation of basal keratinocytes. Reduced expression of Keratin 10 (K10) resulting from Cdk5 knockdown may be responsible for an abnormal epidermal structure. In contrast, overexpression of Cdk5 in sheep (Ovis aries) only produces brown patches on a white background, with no other observable abnormalities. Collectively, our findings show that Cdk5 has an important functional role in the regulation of melanin production and transportation and in normal development of the integumentary system.

MINA controls proliferation and tumorigenesis of glioblastoma by epigenetically regulating cyclins and CDKs via H3K9me3 demethylation.

Science.gov (United States)

Huang, M-Y; Xuan, F; Liu, W; Cui, H-J

2017-01-19

It is generally known that histone demethylases regulate gene transcription by altering the methylate status on histones, but their roles in cancers and the underlying molecular mechanisms still remain unclear. MYC-induced nuclear antigen (MINA) is reported to be a histone demethylase and highly expressed in many cancers. Here, for the first time, we show that MINA is involved in glioblastoma carcinogenesis and reveal the probable mechanisms of it in cell-cycle control. Kaplan-Meier analysis of progression-free survival showed that high MINA expression was strongly correlated with poor outcome and advancing tumor stage. MINA knockdown significantly repressed the cell proliferation and tumorigenesis abilities of glioblastoma cells in vitro and in vivo that were rescued by overexpressing the full-length MINA afterwards. Microarray analysis after knockdown of MINA revealed that MINA probably regulated glioblastoma carcinogenesis through the predominant cell-cycle pathways. Further investigation showed that MINA deficiency led to a cell-cycle arrest in G1 and G2 phases. And among the downstream genes, we found that cyclins and cyclin-dependent kinases were directly activated by MINA via the demethylation of H3K9me3.

Novel arylazopyrazole inhibitors of cyclin-dependent kinases

Czech Academy of Sciences Publication Activity Database

Jorda, Radek; Schütznerová, E.; Cankař, P.; Brychtová, Veronika; Navrátilová, Jana; Kryštof, Vladimír

2015-01-01

Roč. 23, č. 9 (2015), s. 1975-1981 ISSN 0968-0896 R&D Projects: GA ČR GAP305/12/0783; GA ČR GA14-19590S; GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : Cyclin-dependent kinases * Inhibitor * Cell cycle Subject RIV: CE - Biochemistry Impact factor: 2.923, year: 2015

A decrease in cyclin B1 levels leads to polyploidization in DNA damage-induced senescence.

Science.gov (United States)

Kikuchi, Ikue; Nakayama, Yuji; Morinaga, Takao; Fukumoto, Yasunori; Yamaguchi, Naoto

2010-05-04

Adriamycin, an anthracycline antibiotic, has been used for the treatment of various types of tumours. Adriamycin induces at least two distinct types of growth repression, such as senescence and apoptosis, in a concentration-dependent manner. Cellular senescence is a condition in which cells are unable to proliferate further, and senescent cells frequently show polyploidy. Although abrogation of cell division is thought to correlate with polyploidization, the mechanisms underlying induction of polyploidization in senescent cells are largely unclear. We wished, therefore, to explore the role of cyclin B1 level in polyploidization of Adriamycin-induced senescent cells. A subcytotoxic concentration of Adriamycin induced polyploid cells having the features of senescence, such as flattened and enlarged cell shape and activated beta-galactosidase activity. In DNA damage-induced senescent cells, the levels of cyclin B1 were transiently increased and subsequently decreased. The decrease in cyclin B1 levels occurred in G2 cells during polyploidization upon treatment with a subcytotoxic concentration of Adriamycin. In contrast, neither polyploidy nor a decrease in cyclin B1 levels was induced by treatment with a cytotoxic concentration of Adriamycin. These results suggest that a decrease in cyclin B1 levels is induced by DNA damage, resulting in polyploidization in DNA damage-induced senescence.

An activation domain within the walleye dermal sarcoma virus retroviral cyclin protein is essential for inhibition of the viral promoter

International Nuclear Information System (INIS)

Rovnak, Joel; Hronek, Brett W.; Ryan, Sean O.; Cai, Sumin; Quackenbush, Sandra L.

2005-01-01

Walleye dermal sarcoma virus (WDSV) is a complex retrovirus associated with seasonal dermal sarcomas. Developing tumors have low levels of accessory gene transcripts, A1 and B, and regressing tumors have high levels of full-length and spliced transcripts. Transcript A1 encodes a retroviral cyclin (rv-cyclin) with limited homology to host cyclins. The rv-cyclin is physically linked to components of the transcriptional co-activator complex, Mediator, and regulates transcription. In walleye fibroblasts, it inhibits the WDSV promoter independently of cis-acting DNA sequences. The rv-cyclin activates transcription from GAL4 promoters when fused to the GAL4 DNA binding domain. A 30 a.a. activation domain in the carboxy region can be inactivated by single point mutations, and these mutations diminish the ability of the rv-cyclin to inhibit the WDSV promoter. When fused to glutathione S-transferase, the rv-cyclin, its carboxy region, and the activation domain pull down components of transcription complexes from nuclear extracts, and pulldown is lost by mutation of the activation domain

Structural basis of divergent cyclin-dependent kinase activation by Spy1/RINGO proteins

Energy Technology Data Exchange (ETDEWEB)

McGrath, Denise A.; Fifield, Bre-Anne; Marceau, Aimee H.; Tripathi, Sarvind; Porter, Lisa A.; Rubin, Seth M. (UCSC); (Windsor)

2017-06-30

Cyclin-dependent kinases (Cdks) are principal drivers of cell division and are an important therapeutic target to inhibit aberrant proliferation. Cdk enzymatic activity is tightly controlled through cyclin interactions, posttranslational modifications, and binding of inhibitors such as the p27 tumor suppressor protein. Spy1/RINGO (Spy1) proteins bind and activate Cdk but are resistant to canonical regulatory mechanisms that establish cell-cycle checkpoints. Cancer cells exploit Spy1 to stimulate proliferation through inappropriate activation of Cdks, yet the mechanism is unknown. We have determined crystal structures of the Cdk2-Spy1 and p27-Cdk2-Spy1 complexes that reveal how Spy1 activates Cdk. We find that Spy1 confers structural changes to Cdk2 that obviate the requirement of Cdk activation loop phosphorylation. Spy1 lacks the cyclin-binding site that mediates p27 and substrate affinity, explaining why Cdk-Spy1 is poorly inhibited by p27 and lacks specificity for substrates with cyclin-docking sites. We identify mutations in Spy1 that ablate its ability to activate Cdk2 and to proliferate cells. Our structural description of Spy1 provides important mechanistic insights that may be utilized for targeting upregulated Spy1 in cancer.

Cyclin E-induced S phase without activation of the pRb/E2F pathway

DEFF Research Database (Denmark)

Lukas, J; Herzinger, T; Hansen, Klaus

1997-01-01

In cells of higher eukaryotes, cyclin D-dependent kinases Cdk4 and Cdk6 and, possibly, cyclin E-dependent Cdk2 positively regulate the G1- to S-phase transition, by phosphorylating the retinoblastoma protein (pRb), thereby releasing E2F transcription factors that control S-phase genes. Here we...

Tumors initiated by constitutive Cdk2 activation exhibit transforming growth factor beta resistance and acquire paracrine mitogenic stimulation during progression

DEFF Research Database (Denmark)

Corsino, P.; Davis, B.; Law, M.

2007-01-01

Cyclin D1/cyclin-dependent kinase 2 (Cdk2) complexes are present at high frequency in human breast cancer cell lines, but the significance of this observation is unknown. This report shows that expression of a cyclin D1-Cdk2 fusion protein under the control of the mouse mammary tumor virus (MMITV...

A novel transcript of cyclin-dependent kinase-like 5 (CDKL5) has an alternative C-terminus and is the predominant transcript in brain.

Science.gov (United States)

Williamson, Sarah L; Giudici, Laura; Kilstrup-Nielsen, Charlotte; Gold, Wendy; Pelka, Gregory J; Tam, Patrick P L; Grimm, Andrew; Prodi, Dionigio; Landsberger, Nicoletta; Christodoulou, John

2012-02-01

The X-linked cyclin-dependent kinase-like 5 (CDKL5) gene is an important molecular determinant of early-onset intractable seizures with infantile spasms and Rett syndrome-like phenotype. The gene encodes a kinase that may influence components of molecular pathways associated with MeCP2. In humans there are two previously reported splice variants that differ in the 5' untranslated exons and produce the same 115 kDa protein. Furthermore, very recently, a novel transcript including a novel exon (16b) has been described. By aligning both the human and mouse CDKL5 proteins to the orthologs of other species, we identified a theoretical 107 kDa isoform with an alternative C-terminus that terminates in intron 18. In human brain and all other tissues investigated except the testis, this novel isoform is the major CDKL5 transcript. The detailed characterisation of this novel isoform of CDKL5 reveals functional and subcellular localisation attributes that overlap greatly, but not completely, with that of the previously studied human CDKL5 protein. Considering its predominant expression in the human and mouse brain, we believe that this novel isoform is likely to be of primary pathogenic importance in human diseases associated with CDKL5 deficiency, and suggest that screening of the related intronic sequence should be included in the molecular genetic analyses of patients with a suggestive clinical phenotype.

Gefitinib and luteolin cause growth arrest of human prostate cancer PC-3 cells via inhibition of cyclin G-associated kinase and induction of miR-630.

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Minami A Sakurai

Full Text Available Cyclin G-associated kinase (GAK, a key player in clathrin-mediated membrane trafficking, is overexpressed in various cancer cells. Here, we report that GAK expression is positively correlated with the Gleason score in surgical specimens from prostate cancer patients. Embryonic fibroblasts from knockout mice expressing a kinase-dead (KD form of GAK showed constitutive hyper-phosphorylation of the epidermal growth factor receptor (EGFR. In addition to the well-known EGFR inhibitors gefitinib and erlotinib, the dietary flavonoid luteolin was a potent inhibitor of the Ser/Thr kinase activity of GAK in vitro. Co-administration of luteolin and gefitinib to PC-3 cells had a greater effect on cell viability than administration of either compound alone; this decrease in viability was associated with drastic down-regulation of GAK protein expression. A comprehensive microRNA array analysis revealed increased expression of miR-630 and miR-5703 following treatment of PC-3 cells with luteolin and/or gefitinib, and exogenous overexpression of miR-630 caused growth arrest of these cells. GAK appears to be essential for cell death because co-administration of gefitinib and luteolin to EGFR-deficient U2OS osteosarcoma cells also had a greater effect on cell viability than administration of either compound alone. Taken together, these findings suggest that GAK may be a new therapeutic target for prostate cancer and osteosarcoma.

Spatial Reorganization of the Endoplasmic Reticulum during Mitosis Relies on Mitotic Kinase Cyclin A in the Early Drosophila Embryo

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Bergman, Zane J.; Mclaurin, Justin D.; Eritano, Anthony S.; Johnson, Brittany M.; Sims, Amanda Q.; Riggs, Blake

2015-01-01

Mitotic cyclin-dependent kinase with their cyclin partners (cyclin:Cdks) are the master regulators of cell cycle progression responsible for regulating a host of activities during mitosis. Nuclear mitotic events, including chromosome condensation and segregation have been directly linked to Cdk activity. However, the regulation and timing of cytoplasmic mitotic events by cyclin:Cdks is poorly understood. In order to examine these mitotic cytoplasmic events, we looked at the dramatic changes in the endoplasmic reticulum (ER) during mitosis in the early Drosophila embryo. The dynamic changes of the ER can be arrested in an interphase state by inhibition of either DNA or protein synthesis. Here we show that this block can be alleviated by micro-injection of Cyclin A (CycA) in which defined mitotic ER clusters gathered at the spindle poles. Conversely, micro-injection of Cyclin B (CycB) did not affect spatial reorganization of the ER, suggesting CycA possesses the ability to initiate mitotic ER events in the cytoplasm. Additionally, RNAi-mediated simultaneous inhibition of all 3 mitotic cyclins (A, B and B3) blocked spatial reorganization of the ER. Our results suggest that mitotic ER reorganization events rely on CycA and that control and timing of nuclear and cytoplasmic events during mitosis may be defined by release of CycA from the nucleus as a consequence of breakdown of the nuclear envelope. PMID:25689737

Knockdown of ZFR suppresses cell proliferation and invasion of human pancreatic cancer

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Xiaolan Zhao

Full Text Available BACKGROUND: Zinc finger RNA binding protein (ZFR is involved in the regulation of growth and cancer development. However, little is known about ZFR function in pancreatic cancer. METHODS: Herein, to investigate whether ZFR is involved in tumor growth, Oncomine microarray data was firstly used to evaluate ZFR gene expression in human pancreatic tumors. Then short hairpin RNA (shRNA targeting ZFR was designed and delivered into PANC-1 pancreatic cancer cells to knock down ZFR expression. Cell viability, cell proliferation and cell cycle analysis after ZFR knockdown were determined by MTT, colony forming and FACS, respectively. In addition, cell migration and invasion were assessed using the Transwell system. RESULTS: The expression of ZFR was significantly higher in pancreatic tumors than normal pancreas tissues by Oncomine database analysis. Knockdown of ZFR by shRNA-expressing lentivirus significantly decreased the viability and invasion ability of pancreatic cancer cells. Moreover, FACS analysis showed that knockdown of ZFR in PANC-1 cells caused a significant cell cycle arrest at G0/G1 phase. Furthermore, knockdown of ZFR decreased the levels of CDK2, CDK4, CyclinA and CyclinD1 and enhanced the expression of p27, which has evidenced by qRT-PCR and Western blot analysis. CONCLUSIONS: Knockdown of ZFR might provide a novel alternative to targeted therapy of pancreatic cancer and deserves further investigation.

Down-regulation of hTERT and Cyclin D1 transcription via PI3K/Akt and TGF-β pathways in MCF-7 Cancer cells with PX-866 and Raloxifene

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Peek, Gregory W. [Department of Biology, University of Alabama at Birmingham, Birmingham, AL (United States); Tollefsbol, Trygve O., E-mail: trygve@uab.edu [Department of Biology, University of Alabama at Birmingham, Birmingham, AL (United States); Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL (United States); Comprehensive Center for Healthy Aging, University of Alabama at Birmingham, Birmingham, AL (United States); Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL (United States); Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL (United States)

2016-05-15

Human telomerase reverse transcriptase (hTERT) is the catalytic and limiting component of telomerase and also a transcription factor. It is critical to the integrity of the ends of linear chromosomes and to the regulation, extent and rate of cell cycle progression in multicellular eukaryotes. The level of hTERT expression is essential to a wide range of bodily functions and to avoidance of disease conditions, such as cancer, that are mediated in part by aberrant level and regulation of cell cycle proliferation. Value of a gene in regulation depends on its ability to both receive input from multiple sources and transmit signals to multiple effectors. The expression of hTERT and the progression of the cell cycle have been shown to be regulated by an extensive network of gene products and signaling pathways, including the PI3K/Akt and TGF-β pathways. The PI3K inhibitor PX-866 and the competitive estrogen receptor ligand raloxifene have been shown to modify progression of those pathways and, in combination, to decrease proliferation of estrogen receptor positive (ER+) MCF-7 breast cancer cells. We found that combinations of modulators of those pathways decreased not only hTERT transcription but also transcription of additional essential cell cycle regulators such as Cyclin D1. By evaluating known expression profile signatures for TGF-β pathway diversions, we confirmed additional genes such as heparin-binding epidermal growth factor-like growth factor (HB EGF) by which those pathways and their perturbations may also modify cell cycle progression. - Highlights: • PX-866 and raloxifene affect the PI3K/Akt and TGF-β pathways. • PX-866 and raloxifene down-regulate genes up-regulated in cancer. • PX-866 and raloxifene decrease transcription of hTERT and Cyclin D1. • Pathological transcription signatures can identify new defense mechanisms.

Aspirin regulation of c-myc and cyclinD1 proteins to overcome tamoxifen resistance in estrogen receptor-positive breast cancer cells.

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Cheng, Ran; Liu, Ya-Jing; Cui, Jun-Wei; Yang, Man; Liu, Xiao-Ling; Li, Peng; Wang, Zhan; Zhu, Li-Zhang; Lu, Si-Yi; Zou, Li; Wu, Xiao-Qin; Li, Yu-Xia; Zhou, You; Fang, Zheng-Yu; Wei, Wei

2017-05-02

Tamoxifen is still the most commonly used endocrine therapy drug for estrogen receptor (ER)-positive breast cancer patients and has an excellent outcome, but tamoxifen resistance remains a great impediment to successful treatment. Recent studies have prompted an anti-tumor effect of aspirin. Here, we demonstrated that aspirin not only inhibits the growth of ER-positive breast cancer cell line MCF-7, especially when combined with tamoxifen, but also has a potential function to overcome tamoxifen resistance in MCF-7/TAM. Aspirin combined with tamoxifen can down regulate cyclinD1 and block cell cycle in G0/G1 phase. Besides, tamoxifen alone represses c-myc, progesterone receptor (PR) and cyclinD1 in MCF-7 cell line but not in MCF-7/TAM, while aspirin combined with tamoxifen can inhibit the expression of these proteins in the resistant cell line. When knocking down c-myc in MCF-7/TAM, cells become more sensitive to tamoxifen, cell cycle is blocked as well, indicating that aspirin can regulate c-myc and cyclinD1 proteins to overcome tamoxifen resistance. Our study discovered a novel role of aspirin based on its anti-tumor effect, and put forward some kinds of possible mechanisms of tamoxifen resistance in ER-positive breast cancer cells, providing a new strategy for the treatment of ER-positive breast carcinoma.

Alteronol induces cell cycle arrest and apoptosis via increased reactive oxygen species production in human breast cancer T47D cells.

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Ren, Boxue; Li, Defang; Si, Lingling; Ding, Yangfang; Han, Jichun; Chen, Xiaoyu; Zheng, Qiusheng

2018-04-01

Emerging evidence showed that alteronol has a potential antitumour effect in several tumour cells. However, the antitumour effect of alteronol on breast cancer has not been reported. This study investigated the mechanisms of alteronol-induced cell proliferation inhibition in human breast cancer T47D cells. After treatment with alteronol, T47D cell proliferation was examined by MTT assay. The cell cycle distribution, cell apoptosis, reactive oxygen species level and mitochondrial membrane potential were evaluated via flow cytometry. Next, the protein levels of cyclin B1, cdc2, p21, p-cyclin B1, p-cdc2, p53, Bax, Bcl-2 and cytochrome c were analysed using Western blot analysis. Meanwhile, the mRNA levels of cyclin B1, cdc2, p21 and p53 were examined by qRT-PCR. Our data showed that alteronol inhibited the proliferation of T47D cells via inducing G2-phase arrest and cell apoptosis. Compared with control group, alteronol significantly increased ROS level and triggered mitochondrial dysfunction in alteronol-treated T47D cells. Further studies showed that the mRNA and protein levels of cdc2 and cyclin B1 were downregulated, while the mRNA and protein levels of p21, p53, p-cyclin B1, p-cdc2 and cytochrome c were upregulated. In addition, the expression level of Bax was increased, and the expression level of Bcl-2 was decreased. Alteronol induced T47D cell cycle arrest and cell apoptosis through increasing ROS production and triggering mitochondrial dysfunction, and subsequently inhibiting T47D cell proliferation. © 2018 Royal Pharmaceutical Society.

Cadmium modifies the cell cycle and apoptotic profiles of human breast cancer cells treated with 5-fluorouracil.

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Asara, Yolande; Marchal, Juan A; Carrasco, Esther; Boulaiz, Houria; Solinas, Giuliana; Bandiera, Pasquale; Garcia, Maria A; Farace, Cristiano; Montella, Andrea; Madeddu, Roberto

2013-08-12

Industrialisation, the proximity of factories to cities, and human work activities have led to a disproportionate use of substances containing heavy metals, such as cadmium (Cd), which may have deleterious effects on human health. Carcinogenic effects of Cd and its relationship with breast cancer, among other tumours, have been reported. 5-Fluorouracil (5-FU) is a fluoropyrimidine anticancer drug used to treat solid tumours of the colon, breast, stomach, liver, and pancreas. The purpose of this work was to study the effects of Cd on cell cycle, apoptosis, and gene and protein expression in MCF-7 breast cancer cells treated with 5-FU. Cd altered the cell cycle profile, and its effects were greater when used either alone or in combination with 5-FU compared with 5-FU alone. Cd significantly suppressed apoptosis of MCF-7 cells pre-treated with 5-FU. Regarding gene and protein expression, bcl2 expression was mainly upregulated by all treatments involving Cd. The expression of caspase 8 and caspase 9 was decreased by most of the treatments and at all times evaluated. C-myc expression was increased by all treatments involving Cd, especially 5-FU plus Cd at the half time of treatment. Cd plus 5-FU decreased cyclin D1 and increased cyclin A1 expression. In conclusion, our results indicate that exposure to Cd blocks the anticancer effects of 5-FU in MCF-7 cells. These results could have important clinical implications in patients treated with 5-FU-based therapies and who are exposed to high levels of Cd.

Cadmium Modifies the Cell Cycle and Apoptotic Profiles of Human Breast Cancer Cells Treated with 5-Fluorouracil

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Roberto Madeddu

2013-08-01

Full Text Available Industrialisation, the proximity of factories to cities, and human work activities have led to a disproportionate use of substances containing heavy metals, such as cadmium (Cd, which may have deleterious effects on human health. Carcinogenic effects of Cd and its relationship with breast cancer, among other tumours, have been reported. 5-Fluorouracil (5-FU is a fluoropyrimidine anticancer drug used to treat solid tumours of the colon, breast, stomach, liver, and pancreas. The purpose of this work was to study the effects of Cd on cell cycle, apoptosis, and gene and protein expression in MCF-7 breast cancer cells treated with 5-FU. Cd altered the cell cycle profile, and its effects were greater when used either alone or in combination with 5-FU compared with 5-FU alone. Cd significantly suppressed apoptosis of MCF-7 cells pre-treated with 5-FU. Regarding gene and protein expression, bcl2 expression was mainly upregulated by all treatments involving Cd. The expression of caspase 8 and caspase 9 was decreased by most of the treatments and at all times evaluated. C-myc expression was increased by all treatments involving Cd, especially 5-FU plus Cd at the half time of treatment. Cd plus 5-FU decreased cyclin D1 and increased cyclin A1 expression. In conclusion, our results indicate that exposure to Cd blocks the anticancer effects of 5-FU in MCF-7 cells. These results could have important clinical implications in patients treated with 5-FU-based therapies and who are exposed to high levels of Cd.

Cadmium Modifies the Cell Cycle and Apoptotic Profiles of Human Breast Cancer Cells Treated with 5-Fluorouracil

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Asara, Yolande; Marchal, Juan A.; Carrasco, Esther; Boulaiz, Houria; Solinas, Giuliana; Bandiera, Pasquale; Garcia, Maria A.; Farace, Cristiano; Montella, Andrea; Madeddu, Roberto

2013-01-01

Industrialisation, the proximity of factories to cities, and human work activities have led to a disproportionate use of substances containing heavy metals, such as cadmium (Cd), which may have deleterious effects on human health. Carcinogenic effects of Cd and its relationship with breast cancer, among other tumours, have been reported. 5-Fluorouracil (5-FU) is a fluoropyrimidine anticancer drug used to treat solid tumours of the colon, breast, stomach, liver, and pancreas. The purpose of this work was to study the effects of Cd on cell cycle, apoptosis, and gene and protein expression in MCF-7 breast cancer cells treated with 5-FU. Cd altered the cell cycle profile, and its effects were greater when used either alone or in combination with 5-FU compared with 5-FU alone. Cd significantly suppressed apoptosis of MCF-7 cells pre-treated with 5-FU. Regarding gene and protein expression, bcl2 expression was mainly upregulated by all treatments involving Cd. The expression of caspase 8 and caspase 9 was decreased by most of the treatments and at all times evaluated. C-myc expression was increased by all treatments involving Cd, especially 5-FU plus Cd at the half time of treatment. Cd plus 5-FU decreased cyclin D1 and increased cyclin A1 expression. In conclusion, our results indicate that exposure to Cd blocks the anticancer effects of 5-FU in MCF-7 cells. These results could have important clinical implications in patients treated with 5-FU-based therapies and who are exposed to high levels of Cd. PMID:23941782

Therapeutically targeting cyclin D1 in primary tumors arising from loss of Ini1

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Smith, Melissa E.; Cimica, Velasco; Chinni, Srinivasa; Jana, Suman; Koba, Wade; Yang, Zhixia; Fine, Eugene; Zagzag, David; Montagna, Cristina; Kalpana, Ganjam V.

2011-01-01

Rhabdoid tumors (RTs) are rare, highly aggressive pediatric malignancies with poor prognosis and with no standard or effective treatment strategies. RTs are characterized by biallelic inactivation of the INI1 tumor suppressor gene. INI1 directly represses CCND1 and activates cyclin-dependent kinase (cdk) inhibitors p16Ink4a and p21CIP. RTs are exquisitely dependent on cyclin D1 for genesis and survival. To facilitate translation of unique therapeutic strategies, we have used genetically engineered, Ini1+/− mice for therapeutic testing. We found that PET can be used to noninvasively and accurately detect primary tumors in Ini1+/− mice. In a PET-guided longitudinal study, we found that treating Ini1+/− mice bearing primary tumors with the pan-cdk inhibitor flavopiridol resulted in complete and stable regression of some tumors. Other tumors showed resistance to flavopiridol, and one of the resistant tumors overexpressed cyclin D1, more than flavopiridol-sensitive cells. The concentration of flavopiridol used was not sufficient to down-modulate the high level of cyclin D1 and failed to induce cell death in the resistant cells. Furthermore, FISH and PCR analyses indicated that there is aneuploidy and increased CCND1 copy number in resistant cells. These studies indicate that resistance to flavopiridol may be correlated to elevated cyclin D1 levels. Our studies also indicate that Ini1+/− mice are valuable tools for testing unique therapeutic strategies and for understanding mechanisms of drug resistance in tumors that arise owing to loss of Ini1, which is essential for developing effective treatment strategies against these aggressive tumors. PMID:21173237

PPARγ1 phosphorylation enhances proliferation and drug resistance in human fibrosarcoma cells

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Pang, Xiaojuan; Shu, Yuxin; Niu, Zhiyuan; Zheng, Wei; Wu, Haochen [State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing (China); Lu, Yan, E-mail: luyan@nju.edu.cn [State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing (China); Shen, Pingping, E-mail: ppshen@nju.edu.cn [State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing (China); Model Animal Research Center (MARC), Nanjing University, Nanjing (China)

2014-03-10

Post-translational regulation plays a critical role in the control of cell growth and proliferation. The phosphorylation of peroxisome proliferator-activated receptor γ (PPARγ) is the most important post-translational modification. The function of PPARγ phosphorylation has been studied extensively in the past. However, the relationship between phosphorylated PPARγ1 and tumors remains unclear. Here we investigated the role of PPARγ1 phosphorylation in human fibrosarcoma HT1080 cell line. Using the nonphosphorylation (Ser84 to alanine, S84A) and phosphorylation (Ser84 to aspartic acid, S84D) mutant of PPARγ1, the results suggested that phosphorylation attenuated PPARγ1 transcriptional activity. Meanwhile, we demonstrated that phosphorylated PPARγ1 promoted HT1080 cell proliferation and this effect was dependent on the regulation of cell cycle arrest. The mRNA levels of cyclin-dependent kinase inhibitor (CKI) p21{sup Waf1/Cip1} and p27{sup Kip1} descended in PPARγ1{sup S84D} stable HT1080 cell, whereas the expression of p18{sup INK4C} was not changed. Moreover, compared to the PPARγ1{sup S84A}, PPARγ1{sup S84D} up-regulated the expression levels of cyclin D1 and cyclin A. Finally, PPARγ1 phosphorylation reduced sensitivity to agonist rosiglitazone and increased resistance to anticancer drug 5-fluorouracil (5-FU) in HT1080 cell. Our findings establish PPARγ1 phosphorylation as a critical event in human fibrosarcoma growth. These findings raise the possibility that chemical compounds that prevent the phosphorylation of PPARγ1 could act as anticancer drugs. - Highlights: • Phosphorylation attenuates PPARγ1 transcriptional activity. • Phosphorylated PPARγ1 promotes HT1080 cells proliferation. • PPARγ1 phosphorylation regulates cell cycle by mediating expression of cell cycle regulators. • PPARγ1 phosphorylation reduces sensitivity to agonist and anticancer drug. • Our findings establish PPARγ1 phosphorylation as a critical event in HT1080

Cell cycle gene expression under clinorotation

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Artemenko, Olga

2016-07-01

Cyclins and cyclin-dependent kinase (CDK) are main regulators of the cell cycle of eukaryotes. It's assumes a significant change of their level in cells under microgravity conditions and by other physical factors actions. The clinorotation use enables to determine the influence of gravity on simulated events in the cell during the cell cycle - exit from the state of quiet stage and promotion presynthetic phase (G1) and DNA synthesis phase (S) of the cell cycle. For the clinorotation effect study on cell proliferation activity is the necessary studies of molecular mechanisms of cell cycle regulation and development of plants under altered gravity condition. The activity of cyclin D, which is responsible for the events of the cell cycle in presynthetic phase can be controlled by the action of endogenous as well as exogenous factors, but clinorotation is one of the factors that influence on genes expression that regulate the cell cycle.These data can be used as a model for further research of cyclin - CDK complex for study of molecular mechanisms regulation of growth and proliferation. In this investigation we tried to summarize and analyze known literature and own data we obtained relatively the main regulators of the cell cycle in altered gravity condition.

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay.

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Cui, Heying; Loftus, Kyle M; Noell, Crystal R; Solmaz, Sozanne R

2018-05-03

Cyclin-dependent kinase 1 (Cdk1) is a master controller for the cell cycle in all eukaryotes and phosphorylates an estimated 8 - 13% of the proteome; however, the number of identified targets for Cdk1, particularly in human cells is still low. The identification of Cdk1-specific phosphorylation sites is important, as they provide mechanistic insights into how Cdk1 controls the cell cycle. Cell cycle regulation is critical for faithful chromosome segregation, and defects in this complicated process lead to chromosomal aberrations and cancer. Here, we describe an in vitro kinase assay that is used to identify Cdk1-specific phosphorylation sites. In this assay, a purified protein is phosphorylated in vitro by commercially available human Cdk1/cyclin B. Successful phosphorylation is confirmed by SDS-PAGE, and phosphorylation sites are subsequently identified by mass spectrometry. We also describe purification protocols that yield highly pure and homogeneous protein preparations suitable for the kinase assay, and a binding assay for the functional verification of the identified phosphorylation sites, which probes the interaction between a classical nuclear localization signal (cNLS) and its nuclear transport receptor karyopherin α. To aid with experimental design, we review approaches for the prediction of Cdk1-specific phosphorylation sites from protein sequences. Together these protocols present a very powerful approach that yields Cdk1-specific phosphorylation sites and enables mechanistic studies into how Cdk1 controls the cell cycle. Since this method relies on purified proteins, it can be applied to any model organism and yields reliable results, especially when combined with cell functional studies.

Overexpression of p53 activated by small activating RNA suppresses the growth of human prostate cancer cells

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Ge Q

2016-01-01

Full Text Available Qiangqiang Ge,1,* Chenghe Wang,2,* Yajun Ruan,1,* Zhong Chen,1 Jihong Liu,1 Zhangqun Ye1 1Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 2Department of Urology, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, People’s Republic of China *These authors contributed equally to this work Abstract: Previous research has reported that a particular double-stranded RNA, named dsP53-285, has the capacity to induce expression of the tumor suppressor gene TP53 in chimpanzee cells by targeting its promoter. Usually, it is the wild-type p53 protein, rather than mutants, which exhibits potent cancer-inhibiting effects. In addition, nonhuman primates, such as chimpanzees, share almost identical genome sequences with humans. This prompted us to speculate whether dsP53-285 can trigger wild-type p53 protein expression in human prostate cancer (PCa cells and consequently suppress cell growth. The human PCa cell lines LNCaP and DU145 were transfected with dsP53-285 for 72 hours. Compared with the dsControl and mock transfection groups, expression of both p53 messenger RNA and p53 protein was significantly enhanced after dsP53-285 transfection, and this enhancement was followed by upregulation of p21, which indirectly indicated that dsP53-285 induced wild-type p53 expression. Moreover, overexpression of wild-type p53 mediated by dsP53-285 downregulated the expression of Cyclin D1 and cyclin-dependent kinase 4/6, thereby inducing PCa cell cycle arrest in G0/G1 phase and then inhibiting cell proliferation and clonogenicity. More importantly, dsP53-285 suppressed PCa cells mainly by modulating wild-type p53 expression. In conclusion, our study provides evidence that dsP53-285 can significantly stimulate wild-type p53 expression in the human PCa cell lines LNCaP and DU145 and can exert potent antitumor effects. Keywords: p53, small activating RNA, prostate

EDAG promotes the expansion and survival of human CD34+ cells.

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Ke Zhao

Full Text Available EDAG is multifunctional transcriptional regulator primarily expressed in the linloc-kit+Sca-1+ hematopoietic stem cells (HSC and CD34+ progenitor cells. Previous studies indicate that EDAG is required for maintaining hematopoietic lineage commitment balance. Here using ex vivo culture and HSC transplantation models, we report that EDAG enhances the proliferative potential of human cord blood CD34+ cells, increases survival, prevents cell apoptosis and promotes their repopulating capacity. Moreover, EDAG overexpression induces rapid entry of CD34+ cells into the cell cycle. Gene expression profile analysis indicate that EDAG knockdown leads to down-regulation of various positive cell cycle regulators including cyclin A, B, D, and E. Together these data provides novel insights into EDAG in regulation of expansion and survival of human hematopoietic stem/progenitor cells.

Menadione induces G2/M arrest in gastric cancer cells by down-regulation of CDC25C and proteasome mediated degradation of CDK1 and cyclin B1

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Lee, Min Ho; Cho, Yoonjung; Kim, Do Hyun; Woo, Hyun Jun; Yang, Ji Yeong; Kwon, Hye Jin; Yeon, Min Ji; Park, Min; Kim, Sa-Hyun; Moon, Cheol; Tharmalingam, Nagendran; Kim, Tae Ue; Kim, Jong-Bae

2016-01-01

Menadione (vitamin K3) has been reported to induce apoptotic cell death and growth inhibition in various types of cancer cells. However, involvement of menadione in cell cycle control has not been considered in gastric cancer cells yet. In the current study, we have investigated whether menadione is involved in the cell cycle regulation and suppression of growth in gastric cancer cells. In the cell cycle analysis, we found that menadione induced G2/M cell cycle arrest in AGS cells. To elucidate the underlying mechanism, we investigated the cell cycle regulatory molecules involved in the G2/M cell cycle transition. After 24 h of menadione treatment, the protein level of CDK1, CDC25C and cyclin B1 in AGS cells was decreased in a menadione dose-dependent manner. In the time course experiment, the protein level of CDC25C decreased in 6 h, and CDK1and cyclin B1 protein levels began to decrease after 18 h of menadione treatment. We found that mRNA level of CDC25C decreased by menadione treatment in 6 h. Menadione did not have an influence on mRNA level of CDK1 and cyclin B1 though the protein levels were decreased. However, the decreased protein levels of CDK1 and cyclin B1 were recovered by inhibition of proteasome. Collectively, these results suggest that menadione inhibits growth of gastric cancer cells by reducing expression of CDC25C and promoting proteasome mediated degradation of CDK1 and cyclin B1 thereby blocking transition of the cell cycle from G2 phase to M phase. PMID:28077999

IL-21 Receptor Expression in Human Tendinopathy

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Abigail L. Campbell

2014-01-01

Full Text Available The pathogenetic mechanisms underlying tendinopathy remain unclear, with much debate as to whether inflammation or degradation has the prominent role. Increasing evidence points toward an early inflammatory infiltrate and associated inflammatory cytokine production in human and animal models of tendon disease. The IL-21/IL-21R axis is a proinflammatory cytokine complex that has been associated with chronic inflammatory diseases including rheumatoid arthritis and inflammatory bowel disease. This project aimed to investigate the role and expression of the cytokine/receptor pair IL-21/IL-21R in human tendinopathy. We found significantly elevated expression of IL-21 receptor message and protein in human tendon samples but found no convincing evidence of the presence of IL-21 at message or protein level. The level of expression of IL-21R message/protein in human tenocytes was significantly upregulated by proinflammatory cytokines (TNFα/IL-1β in vitro. These findings demonstrate that IL-21R is present in early human tendinopathy mainly expressed by tenocytes and macrophages. Despite a lack of IL-21 expression, these data again suggest that early tendinopathy has an inflammatory/cytokine phenotype, which may provide novel translational targets in the treatment of tendinopathy.

Resveratrol induces cell cycle arrest and apoptosis in human eosinophils from asthmatic individuals.

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Hu, Xin; Wang, Jing; Xia, Yu; Simayi, Mihereguli; Ikramullah, Syed; He, Yuanbing; Cui, Shihong; Li, Shuang; Wushouer, Qimanguli

2016-12-01

Eosinophils exert a number of inflammatory effects through the degranulation and release of intracellular mediators, and are considered to be key effector cells in allergic disorders, including asthma. In order to investigate the regulatory effects of the natural polyphenol, resveratrol, on eosinophils derived from asthmatic individuals, the cell counting Kit‑8 assay and flow cytometry analysis were used to determine cell proliferation and cell cycle progression in these cells, respectively. Cellular apoptosis was detected using annexin V-fluorescein isothiocyanate/propidium iodide double‑staining. The protein expression levels of p53, p21, cyclin‑dependent kinase 2 (CDK2), cyclin A, cyclin E, Bim, B‑cell lymphoma (Bcl)‑2 and Bcl‑2‑associated X protein (Bax) were measured by western blot analysis following resveratrol treatment. The results indicated that resveratrol effectively suppressed the proliferation of eosinophils from asthmatic patients in a concentration‑ and time‑dependent manner. In addition, resveratrol was observed to arrest cell cycle progression in G1/S phase by increasing the protein expression levels of p53 and p21, and concurrently reducing the protein expression levels of CDK2, cyclin A and cyclin E. Furthermore, resveratrol treatment significantly induced apoptosis in eosinophils, likely through the upregulation of Bim and Bax protein expression levels and the downregulation of Bcl‑2 protein expression. These findings suggested that resveratrol may be a potential agent for the treatment of asthma by decreasing the number of eosinophils.

Fisetin induces G2/M phase cell cycle arrest by inactivating cdc25C-cdc2 via ATM-Chk1/2 activation in human endometrial cancer cells

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Zhan-Ying Wang

2015-06-01

Full Text Available Endometrial cancer is one of the most prevalent gynaecological malignancies where, currently available therapeutic options remain limited. Recently phytochemicals are exploited for their efficiency in cancer therapy. The present study investigates the anti-proliferative effect of fisetin, a flavonoid on human endometrial cancer cells (KLE and Hec1 A. Fisetin (20-100 µM effectively reduced the viability of Hec1 A and KLE cells and potentially altered the cell population at G2/M stage. Expression levels of the cell cycle proteins (cyclin B1, p-Cdc2, p-Cdc25C, p-Chk1, Chk2, p-ATM, cyclin B1, H2AX, p21 and p27 were analyzed. Fisetin suppressed cyclin B1 expression and caused inactiva-tion of Cdc25C and Cdc2 by increasing their phosphorylation levels and further activated ATM, Chk1 and Chk2. Increased levels of p21 and p27 were observed as well. These results suggest that fisetin induced G2/M cell cycle arrest via inactivating Cdc25c and Cdc2 through activation of ATM, Chk1 and Chk2.

Human Eosinophils Express Functional CCR7

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Ueki, Shigeharu; Estanislau, Jessica; Weller, Peter F.

2013-01-01

Human eosinophils display directed chemotactic activity toward an array of soluble chemokines. Eosinophils have been observed to migrate to draining lymph nodes in experimental models of allergic inflammation, yet it is unknown whether eosinophils express CCR7, a key chemokine receptor in coordinating leukocyte trafficking to lymph nodes. The purpose of this study is to demonstrate expression of CCR7 by human eosinophils and functional responses to CCL19 and CCL21, the known ligands of CCR7. Human eosinophils were purified by negative selection from healthy donors. CCR7 expression of freshly purified, unstimulated eosinophils and of IL-5–primed eosinophils was determined by flow cytometry and Western blot. Chemotaxis to CCL19 and CCL21 was measured in transwell assays. Shape changes to CCL19 and CCL21 were analyzed by flow cytometry and microscopy. Calcium fluxes of fluo-4 AM–loaded eosinophils were recorded by flow cytometry after chemokine stimulation. ERK phosphorylation of CCL19- and CCL21-stimulated eosinophils was measured by Western blot and Luminex assay. Human eosinophils expressed CCR7 as demonstrated by flow cytometry and Western blots. Eosinophils exhibited detectable cell surface expression of CCR7. IL-5–primed eosinophils exhibited chemotaxis toward CCL19 and CCL21 in a dose-dependent fashion. Upon stimulation with CCL19 or CCL21, IL-5–primed eosinophils demonstrated dose-dependent shape changes with polarization of F-actin and exhibited calcium influxes. Finally, primed eosinophils stimulated with CCL19 or CCL21 exhibited increased phosphorylation of ERK in response to both CCR7 ligands. We demonstrate that human eosinophils express CCR7 and have multipotent responses to the known ligands of CCR7. PMID:23449735

Modulation of human melanoma cell proliferation and apoptosis by hydatid cyst fluid of Echinococcus granulosus

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Gao X

2018-03-01

Full Text Available Xiang-Yang Gao,1,* Guang-Hui Zhang,2,* Li Huang3 1Department of Laboratory Medicine, Pu’er People’s Hospital, Pu’er, 2Department of Clinical Laboratory, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 3Department of General Surgery, Shanghai General Hospital, Shanghai, China *These authors contributed equally to this work Objective: The objective of this paper was to assess the effects of hydatid cyst fluid (HCF of Echinococcus granulosus on melanoma A375 cell proliferation and apoptosis.Methods: A375 cells were classified into five groups by in vitro culture: normal group, control group, 10% HCF group, 20% HCF group and 30% HCF group. Trypan blue staining method was employed to detect the toxicity of HCF. Effects of different concentrations of HCF on melanoma A375 cell proliferation at different time points were evaluated using the 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay. Flow cytometry and propidium iodide (PI staining were used to detect cell cycle, and Annexin-V/PI double staining method was used to determine A375 cell apoptotic rate. Western blotting was applied to detect the expression of phosphorylated extracellular regulated protein kinases, proliferating cell nuclear antigen (PCNA, cell-cycle-related proteins (cyclin A, cyclin B1, cyclin D1 and cyclin E and apoptosis-related proteins (Bcl-2, Bax and caspase-3.Results: HCF with a high concentration was considered as atoxic to A375 cells. HCF promoted A375 cell proliferation, and the effects got stronger with an increase in concentrations but was retarded after reaching a certain range of concentrations. HCF increased phosphorylation level and expression of extracellular regulated protein kinase, as well as PCNA expression. HCF also promoted the transferring progression of A375 cells from the G0/G1 phase to the S phase to increase the cell number in S phase and increased the expression of cyclin A, cyclin D1 and

Regenerating human muscle fibres express GLUT3 protein

DEFF Research Database (Denmark)

Gaster, M; Beck-Nielsen, H; Schrøder, H D

2002-01-01

The presence of the GLUT3 glucose transporter protein in human muscle cells is a matter of debate. The present study was designed to establish whether GLUT3 is expressed in mature human skeletal muscle fibres and, if so, whether its expression changes under different conditions, such as metabolic...... muscle fibres, nor did metabolic stress, training or de- and re-innervation induce GLUT3 expression, while a few GLUT3 expressing fibres were seen in some cases of polymyositis. In contrast, GLUT4 was expressed in all investigated muscle fibres. GLUT3 immunoreactivity was found in perineural...... and endoneural cells, indicating that GLUT3 is important for glucose transport into nerves through the perineurium. Taken together, these data suggest that GLUT3 expression is restricted to regenerating muscle fibres and nerves in adult human muscle. Although the significance of GLUT3 in adult human muscle...

DYRK1A-mediated Cyclin D1 Degradation in Neural Stem Cells Contributes to the Neurogenic Cortical Defects in Down Syndrome

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Sònia Najas

2015-02-01

Full Text Available Alterations in cerebral cortex connectivity lead to intellectual disability and in Down syndrome, this is associated with a deficit in cortical neurons that arises during prenatal development. However, the pathogenic mechanisms that cause this deficit have not yet been defined. Here we show that the human DYRK1A kinase on chromosome 21 tightly regulates the nuclear levels of Cyclin D1 in embryonic cortical stem (radial glia cells, and that a modest increase in DYRK1A protein in transgenic embryos lengthens the G1 phase in these progenitors. These alterations promote asymmetric proliferative divisions at the expense of neurogenic divisions, producing a deficit in cortical projection neurons that persists in postnatal stages. Moreover, radial glial progenitors in the Ts65Dn mouse model of Down syndrome have less Cyclin D1, and Dyrk1a is the triplicated gene that causes both early cortical neurogenic defects and decreased nuclear Cyclin D1 levels in this model. These data provide insights into the mechanisms that couple cell cycle regulation and neuron production in cortical neural stem cells, emphasizing that the deleterious effect of DYRK1A triplication in the formation of the cerebral cortex begins at the onset of neurogenesis, which is relevant to the search for early therapeutic interventions in Down syndrome.

Positive selection on gene expression in the human brain

DEFF Research Database (Denmark)

Khaitovich, Philipp; Tang, Kun; Franz, Henriette

2006-01-01

Recent work has shown that the expression levels of genes transcribed in the brains of humans and chimpanzees have changed less than those of genes transcribed in other tissues [1] . However, when gene expression changes are mapped onto the evolutionary lineage in which they occurred, the brain...... shows more changes than other tissues in the human lineage compared to the chimpanzee lineage [1] , [2] and [3] . There are two possible explanations for this: either positive selection drove more gene expression changes to fixation in the human brain than in the chimpanzee brain, or genes expressed...... in the brain experienced less purifying selection in humans than in chimpanzees, i.e. gene expression in the human brain is functionally less constrained. The first scenario would be supported if genes that changed their expression in the brain in the human lineage showed more selective sweeps than other genes...

Hyaluronic acid enhances proliferation of human amniotic mesenchymal stem cells through activation of Wnt/β-catenin signaling pathway

Energy Technology Data Exchange (ETDEWEB)

Liu, Ru-Ming; Sun, Ren-Gang; Zhang, Ling-Tao; Zhang, Qing-Fang; Chen, Dai-Xiong [Guizhou Center for Translational Medicine, Affiliated Hospital of Zunyi Medical University, 149 Dalian Road, Zunyi 563000 (China); Zhong, Jian-Jiang, E-mail: jjzhong@sjtu.edu.cn [State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240 (China); Xiao, Jian-Hui, E-mail: jhxiao@yahoo.com [Guizhou Center for Translational Medicine, Affiliated Hospital of Zunyi Medical University, 149 Dalian Road, Zunyi 563000 (China)

2016-07-15

This study investigated the pro-proliferative effect of hyaluronic acid (HA) on human amniotic mesenchymal stem cells (hAMSCs) and the underlying mechanisms. Treatment with HA increased cell population growth in a dose- and time-dependent manner. Analyses by flow cytometry and immunocytochemistry revealed that HA did not change the cytophenotypes of hAMSCs. Additionally, the osteogenic, chondrogenic, and adipogenic differentiation capabilities of these hAMSCs were retained after HA treatment. Moreover, HA increased the mRNA expressions of wnt1, wnt3a, wnt8a, cyclin D1, Ki-67, and β-catenin as well as the protein level of β-catenin and cyclin D1 in hAMSCs; and the nuclear localization of β-catenin was also enhanced. Furthermore, the pro-proliferative effect of HA and up-regulated expression of Wnt/β-catenin pathway-associated proteins - wnt3a, β-catenin and cyclin D1 in hAMSCs were significantly inhibited upon pre-treatment with Wnt-C59, an inhibitor of the Wnt/β-catenin pathway. These results suggest that HA may positively regulate hAMSCs proliferation through regulation of the Wnt/β-catenin signaling pathway. - Highlights: • Hyaluronic acid (HA) could promote the proliferation of hAMSCs. • HA treatment dose not affect the pluripotency of hAMSCs. • HA increases hAMSCs proliferation through activation of Wnt/β-catenin signaling.

Proteasome LMP2/β1i subunit as biomarker for human uterine leiomyosarcoma

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Takuma Hayashi

2014-02-01

Full Text Available Uterine leiomyosarcoma (Ut-LMS develops more frequently in the myometrium of the uterine body than in the uterine cervix. Although the development of gynecological tumors is often correlated with the secretion of female hormones that of Ut-LMS does not, and its risk factor(s remain unknown. Importantly, a diagnostic biomarker that can distinguish malignant tumor Ut-LMS from benign tumor leiomyoma (LMA, has yet to be established. Therefore, the risk factor(s associated with Ut-LMS need to be examined in order to establish a diagnosis and clinical treatment method. Mice with a homozygous deficiency for the proteasome b-ring subunit, low-molecular mass polypeptide (LMP2/b1i spontaneously develop Ut-LMS, with a disease prevalence of ~40% by 14 months of age. In recent studies, we showed that LMP2/b1i expression was absent in human Ut-LMS, but present in other human uterine mesenchymal tumors including uterine LMA. Moreover, LMP2/b1i is also known to negatively regulate human Ut-LMS tumorigenesis. Additional experiments furthermore revealed the differential expression of cyclin E and calponin h1 in human uterine mesenchymal tumors. Therefore, LMP2/b1i is a potential diagnostic biomarker when combined with the candidate molecules, cyclin E and calponin h1 for human Ut-LMS, and may be a targeted molecule for a new therapeutic approach.---------------------------------------------Cite this article as: Hayashi T, Horiuchi A Aburatani H, Ishiko O, Yaegashi N, Kanai Y, Zharhary D, Tonegawa S, Konishi I. Proteasome LMP2/ß1i subunit as biomarker for human uterine leiomyosarcoma. Int J Cancer Ther Oncol 2014; 2(1:02018.DOI: http://dx.doi.org/10.14319/ijcto.0201.8

Restoration of cyclin D2 has an inhibitory potential on the proliferation of LNCaP cells

International Nuclear Information System (INIS)

Kobayashi, Takashi; Nakamura, Eijiro; Shimizu, Yosuke; Terada, Naoki; Maeno, Atsushi; Kobori, Go; Kamba, Tomomi; Kamoto, Toshiyuki; Ogawa, Osamu; Inoue, Takahiro

2009-01-01

Despite well known oncogenic function of G1-S cell-cycle progression, cyclin D2 (CCND2) is often silenced epigenetically in prostate cancers. Here we show that CCND2 has an inhibitory potential on the proliferation of androgen receptor (AR)-dependent prostate cancer LNCaP cells. Forced expression of CCND2 suppressed the proliferative ability and induced cell death in LNCaP cells in a cdk-independent manner. Knocking down CCND2 restored the proliferation of LNCaP subclones with relatively high CCND2 expression and low proliferative profiles. Immunoprecipitation using deletion mutants of CCND2 indicated that a central domain of CCND2 is required for binding to AR. A deletion mutant lacking the central domain failed to hinder LNCaP cells. Collectively, our results indicated that CCND2 inhibits cell proliferation of AR-dependent prostate cancer through the interaction with AR. Our study suggests that restoration of CCND2 expression potentially prevents the carcinogenesis of prostate cancer, which is mostly AR-dependent in the initial settings.

Origin of cells cultured in vitro from human breast carcinomas traced by cyclin D1 and HER2/neu FISH signal numbers

Czech Academy of Sciences Publication Activity Database

Matoušková, Eva; Kudláčková, Iva; Chaloupková, Alena; Brožová, Markéta; Netíková, I.; Veselý, Pavel

2005-01-01

Roč. 25, 2A (2005), s. 1051-1058 ISSN 0250-7005 R&D Projects: GA MZd(CZ) NR8145 Institutional research plan: CEZ:AV0Z50520514 Keywords : breast carcinomas * primary cultures of carcinoma cells * cyclin D1 and HER2/neu by FISH Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.604, year: 2005

Elevated p16ink4a Expression in Human Labial Salivary Glands as a Potential Correlate of Cognitive Aging in Late Midlife.

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Christiane Elisabeth Sørensen

Full Text Available The cell-cycle inhibitor and tumor suppressor cyclin dependent kinase inhibitor, p16ink4a, is one of the two gene products of the ink4a/ARF (cdkn2a locus on chromosome 9q21. Up-regulation of p16ink4a has been linked to cellular senescence, and findings from studies on different mammalian tissues suggest that p16ink4a may be a biomarker of organismal versus chronological age.The aim of this study was to examine the immunolocalization pattern of p16ink4a in human labial salivary gland (LSG tissue, and to analyze whether its expression level in LSGs is a peripheral correlate of cognitive decline in late midlife.The present study was a part of a study of causes and predictors of cognitive decline in middle-aged men in a Danish birth cohort. It is based on data from 181 male participants from the Danish Metropolit birth cohort, born in 1953, who were examined for age-associated alterations in cognition, dental health, and morphological and autonomic innervation characteristics of the LSGs. The participants were allocated to two groups based on the relative change in cognitive performance from young adulthood to late midlife. LSG biopsies were analyzed by qRT-PCR for the expression level of p16ink4a. Immunohistochemistry was performed on formalin-fixed, paraffin-embedded sections of LSGs.p16ink4a immunoreactivity was observed in LSG ductal, myoepithelial, and stromal cells, but not in acinar cells. The mean relative expression of p16ink4a in LSGs was higher in the group of participants with decline in cognitive performance. A logistic regression analysis revealed that the relative p16 expression was predictive of the participant's group assignment. A negative correlation was found between relative p16ink4a expression and the participant's standardized regression residuals from early adulthood to late midlife cognitive performance scores.p16ink4a expression in human LSGs may constitute a potential peripheral correlate of cognitive decline. Human labial

RITA inhibits growth of human hepatocellular carcinoma through induction of apoptosis.

Science.gov (United States)

Wang, Haihe; Chen, Guofu; Wang, Hongzhi; Liu, Chunbo

2013-01-01

RBP-J-interacting and tubulin-associated (RITA) is a novel RBP-J-interacting protein that downregulates Notch-mediated transcription. The current study focuses on the antitumor effect of RITA in human hepatocellular carcinoma (HCC) and aims to explore its molecular mechanism. Thirty paired HCC and adjacent non-tumoral liver samples were analyzed by real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). RITA overexpression was induced by transfection of a pcDNA3.1-Flag-RITA plasmid into HepG2 cells. RITA knockdown was achieved by siRNA transfection. mRNA and protein expression of target genes were quantified by qRT-PCR and Western blotting, respectively. Cell proliferation and apoptosis were measured using MTT assay and flow cytometry. Our results demonstrate that adjacent nontumoral liver samples exhibited increased RITA expression compared to HCC tissues (p RITA levels were associated with tumor differentiation status. Overexpression of RITA suppressed cell proliferation and promoted early apoptosis, while its silencing promoted cell growth dramatically (p RITA overexpression upregulated p53 and reduced cyclin E levels, whereas silencing of RITA had the opposite effect on p53 and cyclin E expression. Our in vitro results represent the first evidence that RITA might suppress tumor growth and induce apoptosis in HCCs, and may be a potent antitumoral agent for HCC treatment that deserves further exploration.

Deregulation of the RB pathway in human testicular germ cell tumours

DEFF Research Database (Denmark)

Bartkova, Jirina; Lukas, Claudia; Sørensen, Claus S

2003-01-01

Deregulation of the RB pathway is shared by most human malignancies. Components upstream of the retinoblastoma tumour suppressor (pRB), namely the INK4 family of cyclin-dependent kinase (CDK) inhibitors, the D-type cyclins, their partner kinases CDK4/CDK6, and pRB as their critical substrate...

Glucose transporter expression in human skeletal muscle fibers

DEFF Research Database (Denmark)

Gaster, M; Handberg, A; Beck-Nielsen, H

2000-01-01

, but its expression is markedly reduced around birth and is further reduced to undetectable levels within the first year of life; 2) GLUT-3 protein expression appears at 18 wk of gestation and disappears after birth; and 3) GLUT-4 protein is diffusely expressed in muscle cells throughout gestation, whereas...... after birth, the characteristic subcellular localization is as seen in adult muscle fibers. Our results show that GLUT-1, GLUT-3, and GLUT-4 seem to be of importance during muscle fiber growth and development. GLUT-5 protein was undetectable in fetal and adult skeletal muscle fibers. In adult muscle...... amplification (TSA) technique to detect the localization of glucose transporter expression in human skeletal muscle. We found expression of GLUT-1, GLUT-3, and GLUT-4 in developing human muscle fibers showing a distinct expression pattern. 1) GLUT-1 is expressed in human skeletal muscle cells during gestation...

Human Empathy, Personality and Experience Affect the Emotion Ratings of Dog and Human Facial Expressions

Science.gov (United States)

Kujala, Miiamaaria V.; Somppi, Sanni; Jokela, Markus; Vainio, Outi; Parkkonen, Lauri

2017-01-01

Facial expressions are important for humans in communicating emotions to the conspecifics and enhancing interpersonal understanding. Many muscles producing facial expressions in humans are also found in domestic dogs, but little is known about how humans perceive dog facial expressions, and which psychological factors influence people’s perceptions. Here, we asked 34 observers to rate the valence, arousal, and the six basic emotions (happiness, sadness, surprise, disgust, fear, and anger/aggressiveness) from images of human and dog faces with Pleasant, Neutral and Threatening expressions. We investigated how the subjects’ personality (the Big Five Inventory), empathy (Interpersonal Reactivity Index) and experience of dog behavior affect the ratings of dog and human faces. Ratings of both species followed similar general patterns: human subjects classified dog facial expressions from pleasant to threatening very similarly to human facial expressions. Subjects with higher emotional empathy evaluated Threatening faces of both species as more negative in valence and higher in anger/aggressiveness. More empathetic subjects also rated the happiness of Pleasant humans but not dogs higher, and they were quicker in their valence judgments of Pleasant human, Threatening human and Threatening dog faces. Experience with dogs correlated positively with ratings of Pleasant and Neutral dog faces. Personality also had a minor effect on the ratings of Pleasant and Neutral faces in both species. The results imply that humans perceive human and dog facial expression in a similar manner, and the perception of both species is influenced by psychological factors of the evaluators. Especially empathy affects both the speed and intensity of rating dogs’ emotional facial expressions. PMID:28114335

Human Empathy, Personality and Experience Affect the Emotion Ratings of Dog and Human Facial Expressions.

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Miiamaaria V Kujala

Full Text Available Facial expressions are important for humans in communicating emotions to the conspecifics and enhancing interpersonal understanding. Many muscles producing facial expressions in humans are also found in domestic dogs, but little is known about how humans perceive dog facial expressions, and which psychological factors influence people's perceptions. Here, we asked 34 observers to rate the valence, arousal, and the six basic emotions (happiness, sadness, surprise, disgust, fear, and anger/aggressiveness from images of human and dog faces with Pleasant, Neutral and Threatening expressions. We investigated how the subjects' personality (the Big Five Inventory, empathy (Interpersonal Reactivity Index and experience of dog behavior affect the ratings of dog and human faces. Ratings of both species followed similar general patterns: human subjects classified dog facial expressions from pleasant to threatening very similarly to human facial expressions. Subjects with higher emotional empathy evaluated Threatening faces of both species as more negative in valence and higher in anger/aggressiveness. More empathetic subjects also rated the happiness of Pleasant humans but not dogs higher, and they were quicker in their valence judgments of Pleasant human, Threatening human and Threatening dog faces. Experience with dogs correlated positively with ratings of Pleasant and Neutral dog faces. Personality also had a minor effect on the ratings of Pleasant and Neutral faces in both species. The results imply that humans perceive human and dog facial expression in a similar manner, and the perception of both species is influenced by psychological factors of the evaluators. Especially empathy affects both the speed and intensity of rating dogs' emotional facial expressions.

Characterization of human septic sera induced gene expression modulation in human myocytes

Science.gov (United States)

Hussein, Shaimaa; Michael, Paul; Brabant, Danielle; Omri, Abdelwahab; Narain, Ravin; Passi, Kalpdrum; Ramana, Chilakamarti V.; Parrillo, Joseph E.; Kumar, Anand; Parissenti, Amadeo; Kumar, Aseem

2009-01-01

To gain a better understanding of the gene expression changes that occurs during sepsis, we have performed a cDNA microarray study utilizing a tissue culture model that mimics human sepsis. This study utilized an in vitro model of cultured human fetal cardiac myocytes treated with 10% sera from septic patients or 10% sera from healthy volunteers. A 1700 cDNA expression microarray was used to compare the transcription profile from human cardiac myocytes treated with septic sera vs normal sera. Septic sera treatment of myocytes resulted in the down-regulation of 178 genes and the up-regulation of 4 genes. Our data indicate that septic sera induced cell cycle, metabolic, transcription factor and apoptotic gene expression changes in human myocytes. Identification and characterization of gene expression changes that occur during sepsis may lead to the development of novel therapeutics and diagnostics. PMID:19684886

Quality of human milk expressed in a human milk bank and at home.

Science.gov (United States)

Borges, Mayla S; Oliveira, Angela M de M; Hattori, Wallisen T; Abdallah, Vânia O S

2017-08-30

To evaluate the quality of the human milk expressed at home and at a human milk bank. This a retrospective, analytical, and observational study, performed by assessing titratable acidity records and the microbiological culture of 100 human milk samples expressed at home and at a human milk bank, in 2014. For the statistical analysis, generalized estimating equations (GEE) and the chi-squared test were used. When comparing the two sample groups, no significant difference was found, with 98% and 94% of the samples being approved among those collected at the milk bank and at home, respectively. No main interaction effect between local and titratable acidity records (p=0.285) was observed, and there was no statistically significant difference between the expected and observed values for the association between the collection place and the microbiological culture results (p=0.307). The quality of human milk expressed at home and at the milk bank are in agreement with the recommended standards, confirming that the expression of human milk at home is as safe as expression at the human milk bank, provided that the established hygiene, conservation, storage, and transport standards are followed. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Viral oncogene-induced DNA damage response is activated in Kaposi sarcoma tumorigenesis.

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Sonja Koopal

2007-09-01

Full Text Available Kaposi sarcoma is a tumor consisting of Kaposi sarcoma herpesvirus (KSHV-infected tumor cells that express endothelial cell (EC markers and viral genes like v-cyclin, vFLIP, and LANA. Despite a strong link between KSHV infection and certain neoplasms, de novo virus infection of human primary cells does not readily lead to cellular transformation. We have studied the consequences of expression of v-cyclin in primary and immortalized human dermal microvascular ECs. We show that v-cyclin, which is a homolog of cellular D-type cyclins, induces replicative stress in ECs, which leads to senescence and activation of the DNA damage response. We find that antiproliferative checkpoints are activated upon KSHV infection of ECs, and in early-stage but not late-stage lesions of clinical Kaposi sarcoma specimens. These are some of the first results suggesting that DNA damage checkpoint response also functions as an anticancer barrier in virally induced cancers.

Retinoblastoma pathway defects show differential ability to activate the constitutive DNA damage response in human tumorigenesis

DEFF Research Database (Denmark)

Tort, F.; Bartkova, J.; Sehested, M.

2006-01-01

culture models with differential defects of retinoblastoma pathway components, as overexpression of cyclin D1 or lack of p16(Ink4a), either alone or combined, did not elicit detectable DDR. In contrast, inactivation of pRb, the key component of the pathway, activated the DDR in cultured human or mouse...... with their hierarchical positions along the retinoblastoma pathway. Our data provide new insights into oncogene-evoked DDR in human tumorigenesis, with potential implications for individualized management of tumors with elevated cyclin D1 versus cyclin E, due to their distinct clinical variables and biological behavior....

The human ubiquitin-conjugating enzyme Cdc34 controls cellular proliferation through regulation of p27Kip1 protein levels

International Nuclear Information System (INIS)

Butz, Nicole; Ruetz, Stephan; Natt, Francois; Hall, Jonathan; Weiler, Jan; Mestan, Juergen; Ducarre, Monique; Grossenbacher, Rita; Hauser, Patrick; Kempf, Dominique; Hofmann, Francesco

2005-01-01

Ubiquitin-mediated degradation of the cyclin-dependent kinase inhibitor p27 Kip1 was shown to be required for the activation of key cyclin-dependent kinases, thereby triggering the onset of DNA replication and cell cycle progression. Although the SCF Skp2 ubiquitin ligase has been reported to mediate p27 Kip1 degradation, the nature of the human ubiquitin-conjugating enzyme involved in this process has not yet been determined at the cellular level. Here, we show that antisense oligonucleotides targeting the human ubiquitin-conjugating enzyme Cdc34 downregulate its expression, inhibit the degradation of p27 Kip1 , and prevent cellular proliferation. Elevation of p27 Kip1 protein level is found to be the sole requirement for the inhibition of cellular proliferation induced upon downregulation of Cdc34. Indeed, reducing the expression of p27 Kip1 with a specific antisense oligonucleotide is sufficient to reverse the anti-proliferative phenotype elicited by the Cdc34 antisense. Furthermore, downregulation of Cdc34 is found to specifically increase the abundance of the SCF Skp2 ubiquitin ligase substrate p27 Kip1 , but has no concomitant effect on the level of IkBα and β-catenin, which are known substrates of a closely related SCF ligase

The heat shock protein 90 inhibitor 17-AAG suppresses growth and induces apoptosis in human cholangiocarcinoma cells.

Science.gov (United States)

Zhang, Jianjun; Zheng, Zhichao; Zhao, Yan; Zhang, Tao; Gu, Xiaohu; Yang, Wei

2013-11-01

The aim of this study was to investigate the effects of 17-Allylamino-17-demethoxygeldanamycin (17-AAG), a heat shock protein 90 (HSP90) inhibitor, on the proliferation, cell cycle, and apoptosis of human cholangiocarcinoma (CCA) cells. Cell proliferation and cell cycle distribution were measured by the MTT assay and flow cytometry analysis, respectively. Induction of apoptosis was determined by flow cytometry and Hoechst staining. The expressions of cleaved poly ADP-ribose polymerase (PARP), Bcl-2, Survivin, and Cyclin B1 were detected by Western blot analysis. The activity of caspase-3 was also examined. We found that 17-AAG inhibited cell growth and induced G2/M cell cycle arrest and apoptosis in CCA cells together with the down-regulation of Bcl-2, Survivin and Cyclin B1, and the up-regulation of cleaved PARP. Moreover, increased caspase-3 activity was also observed in CCA cells treated with 17-AAG. In conclusion, our data suggest that the inhibition of HSP90 function by 17-AAG may provide a promising therapeutic strategy for the treatment of human CCA.

Quantitative Expression Analysis of APP Pathway and Tau Phosphorylation-Related Genes in the ICV STZ-Induced Non-Human Primate Model of Sporadic Alzheimer’s Disease

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Sang-Je Park

2015-01-01

Full Text Available The accumulation and aggregation of misfolded proteins in the brain, such as amyloid-β (Aβ and hyperphosphorylated tau, is a neuropathological hallmark of Alzheimer’s disease (AD. Previously, we developed and validated a novel non-human primate model for sporadic AD (sAD research using intracerebroventricular administration of streptozotocin (icv STZ. To date, no characterization of AD-related genes in different brain regions has been performed. Therefore, in the current study, the expression of seven amyloid precursor protein (APP pathway-related and five tau phosphorylation-related genes was investigated by quantitative real-time PCR experiments, using two matched-pair brain samples from control and icv STZ-treated cynomolgus monkeys. The genes showed similar expression patterns within the control and icv STZ-treated groups; however, marked differences in gene expression patterns were observed between the control and icv STZ-treated groups. Remarkably, other than β-secretase (BACE1 and cyclin-dependent kinase 5 (CDK5, all the genes tested showed similar expression patterns in AD models compared to controls, with increased levels in the precuneus and occipital cortex. However, significant changes in gene expression patterns were not detected in the frontal cortex, hippocampus, or posterior cingulate. Based on these results, we conclude that APP may be cleaved via the general metabolic mechanisms of increased α- and γ-secretase levels, and that hyperphosphorylation of tau could be mediated by elevated levels of tau protein kinase, specifically in the precuneus and occipital cortex.

Genetic effects on gene expression across human tissues

NARCIS (Netherlands)

Battle, Alexis; Brown, Christopher D.; Engelhardt, Barbara E.; Montgomery, Stephen B.; Aguet, François; Ardlie, Kristin G.; Cummings, Beryl B.; Gelfand, Ellen T.; Getz, Gad; Hadley, Kane; Handsaker, Robert E.; Huang, Katherine H.; Kashin, Seva; Karczewski, Konrad J.; Lek, Monkol; Li, Xiao; MacArthur, Daniel G.; Nedzel, Jared L.; Nguyen, Duyen T.; Noble, Michael S.; Segrè, Ayellet V.; Trowbridge, Casandra A.; Tukiainen, Taru; Abell, Nathan S.; Balliu, Brunilda; Barshir, Ruth; Basha, Omer; Bogu, Gireesh K.; Brown, Andrew; Castel, Stephane E.; Chen, Lin S.; Chiang, Colby; Conrad, Donald F.; Cox, Nancy J.; Damani, Farhan N.; Davis, Joe R.; Delaneau, Olivier; Dermitzakis, Emmanouil T.; Eskin, Eleazar; Ferreira, Pedro G.; Frésard, Laure; Gamazon, Eric R.; Garrido-Martín, Diego; Gewirtz, Ariel D. H.; Gliner, Genna; Gloudemans, Michael J.; Guigo, Roderic; Hall, Ira M.; Han, Buhm; He, Yuan

2017-01-01

Characterization of the molecular function of the human genome and its variation across individuals is essential for identifying the cellular mechanisms that underlie human genetic traits and diseases. The Genotype-Tissue Expression (GTEx) project aims to characterize variation in gene expression

Human Alpha Defensin 5 Expression in the Human Kidney and Urinary Tract

Science.gov (United States)

Porter, Edith; Bevins, Charles L.; DiRosario, Julianne; Becknell, Brian; Wang, Huanyu

2012-01-01

Background The mechanisms that maintain sterility in the urinary tract are incompletely understood. Recent studies have implicated the importance of antimicrobial peptides (AMP) in protecting the urinary tract from infection. Here, we characterize the expression and relevance of the AMP human alpha-defensin 5 (HD5) in the human kidney and urinary tract in normal and infected subjects. Methodology/Principal Findings Using RNA isolated from human kidney, ureter, and bladder tissue, we performed quantitative real-time PCR to show that DEFA5, the gene encoding HD5, is constitutively expressed throughout the urinary tract. With pyelonephritis, DEFA5 expression significantly increased in the kidney. Using immunoblot analysis, HD5 production also increased with pyelonephritis. Immunostaining localized HD5 to the urothelium of the bladder and ureter. In the kidney, HD5 was primarily produced in the distal nephron and collecting tubules. Using immunoblot and ELISA assays, HD5 was not routinely detected in non-infected human urine samples while mean urinary HD5 production increased with E.coli urinary tract infection. Conclusions/Significance DEFA5 is expressed throughout the urinary tract in non-infected subjects. Specifically, HD5 is expressed throughout the urothelium of the lower urinary tract and in the collecting tubules of the kidney. With infection, HD5 expression increases in the kidney and levels become detectable in the urine. To our knowledge, our findings represent the first to quantitate HD5 expression and production in the human kidney. Moreover, this is the first report to detect the presence of HD5 in infected urine samples. Our results suggest that HD5 may have an important role in maintaining urinary tract sterility. PMID:22359618

Expression and function of human hemokinin-1 in human and guinea pig airways.

Science.gov (United States)

Grassin-Delyle, Stanislas; Naline, Emmanuel; Buenestado, Amparo; Risse, Paul-André; Sage, Edouard; Advenier, Charles; Devillier, Philippe

2010-10-07

Human hemokinin-1 (hHK-1) and endokinins are peptides of the tachykinin family encoded by the TAC4 gene. TAC4 and hHK-1 expression as well as effects of hHK-1 in the lung and airways remain however unknown and were explored in this study. RT-PCR analysis was performed on human bronchi to assess expression of tachykinin and tachykinin receptors genes. Enzyme immunoassay was used to quantify hHK-1, and effects of hHK-1 and endokinins on contraction of human and guinea pig airways were then evaluated, as well as the role of hHK-1 on cytokines production by human lung parenchyma or bronchi explants and by lung macrophages. In human bronchi, expression of the genes that encode for hHK-1, tachykinin NK1-and NK2-receptors was demonstrated. hHK-1 protein was found in supernatants from explants of human bronchi, lung parenchyma and lung macrophages. Exogenous hHK-1 caused a contractile response in human bronchi mainly through the activation of NK2-receptors, which blockade unmasked a NK1-receptor involvement, subject to a rapid desensitization. In the guinea pig trachea, hHK-1 caused a concentration-dependant contraction mainly mediated through the activation of NK1-receptors. Endokinin A/B exerted similar effects to hHK-1 on both human bronchi and guinea pig trachea, whereas endokinins C and D were inactive. hHK-1 had no impact on the production of cytokines by explants of human bronchi or lung parenchyma, or by human lung macrophages. We demonstrate endogenous expression of TAC4 in human bronchi, the encoded peptide hHK-1 being expressed and involved in contraction of human and guinea pig airways.