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Aims:Non-small cell lung cancer (NSCLC) accounts for high lung cancer death that is mostly associated with advanced disease stage at diagnosis and resistance to chemotherapy. In the present study, we investigated whether xanthohumol, a prenylated flavonoid of hop plant, induces metastatic lung cancer H1299 cell death, and whether in combination with cisplatin there are additive effects. Methodology:H1299 cells were grown and treated with xanthohumol (6.25, 12.5, or 25 μM), cisplatin (12.5, 25, or 50 μM) and the combination of cisplatin and xanthohumol for 24 h. Cell viability, cell morphology, chromatin condensation, ɣH2AX, cPARP-1, capsase-3, p21WAF1/CIP1and p14ARFgenes were analyzed Results:Xanthohumol, cisplatin, and the combination of cisplatin and xanthohumol inhibited H1299 cells viability. Cisplatin growth inhibitory effects were potentiated by xanthohumol. Xanthohumol induced chromatin condensation and apoptosis and potentiated cisplatin’s effect vs cisplatin alone. Further investigation of growth inhibitory effects, xanthohumol alone induced γH2AX foci formation and the combination potentiated γH2AX foci formation. Cisplatin, xanthohumol at 25 μM, and the combination of cisplatin and xanthohumol at 6.25 and 12.5 μM increased cPARP-1 level. Active caspase-3 was increased by cisplatin, 12.5 μM of xanthohumol, and the combination of xanthohumol and cisplatin. Xanthohumol at 6.25 or 12.5 μM potentiated cisplatin effect on active caspase-3 and cPARP-1, respectively. Xanthohumol at 25 μM significtly induced the expression cell cycle control genes p21WAF1/CIP1and p14ARF. These results indicate that xanthohumol inhibits proliferation of H1299 cells and induces cell death through cleavage of PARP-1 and activation of caspase-3. The combination of cisplatin and xanthohumol potentiated cytotoxic effects of each other compound.Conclusion:The present study suggests that xanthohumol poses apoptotic effects and potentiates cisplatin’s growth inhibitory effects on metastatic lung cancer cells
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Aim To study the regulation mechanisms of deacetylase inhibitor SAHA in p21WAF1/CIP1 promoter acetylation in breast cancer MCF-7 cells.Methods We used quantitative real-time PCR, Western blot and DNA-ChIP to determine the effects on the regulation of cell cycle with SAHA treatment in MCF-7 cells.By DNA-ChIP, we assessed the acetylation level of p21WAF1/CIP1 promoter.Results SAHA significantly affected the expression of cell cycle-related factors, and induced the mRNA and protein expression of p21WAF1/CIP1.SAHA could adjust the acetylation level of p21WAF1/CIP1 promoter.Conclusion SAHA regulates the cell cycle progression by adjusting the acetylation level of p21WAF1/CIP1 promoter in MCF-7 cells.
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Aim To investigate the specific binding sites that histone deacetylases 1(HDAC1) and estrogen receptor α(ERα)can be recruited to regulate the transcriptional activity of p21WAF1/CIP1 promoter in the breast cancer MCF-7 cells, and to clarify the molecular mechanism of suberoylanilide hydroxamic acid(SAHA) and leptin regulating p21WAF1/CIP1 promoter function.Methods The breast cancer MCF-7 cells in logarithmic growth phase were starved with FBS free medium for 24 hours, and treated with 20 μmol·L-1 SAHA(SAHA group) or 0.625 nmol·L-1 leptin(Leptin group) for 24 hours.The cells that were cultured in complete RPMI 1640 medium without any treatment were assigned as control group(Basal group).The cell lysis was prepared and incubated respectively with anti-HDAC1 and anti-ERα antibody by chromatin-immunoprecipitation(ChIP) method overnight at 4℃.The DNA-ChIP was followed the manufacturer′s protocol for the assay.DNA fragments binding anti-HDAC1 and anti-ERα antibody were gathered and purified.The relative expression level of DNA fragments from TSS to the upstream of the p21WAF1/CIP1 promoter region(+2~-4 000 bp) binding with antibody was detected by real-time PCR and analyzed by 2-△△CT method.Results In basal group, HDAC1 and ERα had high affinity with the f1 and f8 fragments of p21WAF1/CIP1 promoter compared to the f4 fragment.In SAHA group, the binding ability of HDAC1 and ERα to the f1 and f8 fragments of p21WAF1/CIP1 promoter was significantly lower than that of the control, while reversing to reach the peak after leptin treatment.Conclusions HDAC1 and ERα can be recruited to p21WAF1/CIP1 promoter by the cell proliferation signal during the proliferation of breast cancer MCF-7 cells.The DNA f1(from 0 to-400 bp) and f8(from-2 800 to-3 200 bp) fragment in the upstream of p21WAF1/CIP1 promoter are the target functional region for the binding with HDAC1and ERα.
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Aim Toinvestigatethespecificbinding sites that HDAC1 can be recruited to regulate the tran-scriptional activity of p21 WAF1/CIP1 promoter in the breast cancer MCF-7 cells.Methods ThebreastcancerMCF-7 cells in logarithmic growth phase were starved with FBS free medium for 24 hours,and treated with 20 μmol·L-1 SAHA(S group)or 0. 625 nmol·L-1 Leptin(L group)for 24 hours,and the cells that were cultured in the complete RPMI 1640 medium without any treatment were assigned as control group (B group).The DNA-ChIP was followed the manufactur-er′s protocol for the assay.The cell lysis was prepared and incubated with anti-HDAC1 antibody overnight at 4℃.DNA fragments binding anti-HDAC1 antibody were gathered and purified.The relative expression level of DNA fragments from TSS to the upstream of the p21 WAF1/CIP1 promoter region(+2 ~-4000 bp)bind-ing with antibody was detected by Real-time PCR and analyzedby2-ΔΔCTmethod.Results InBgroup, HDAC1 had high affinity with the f1 and f 8 fragmentsof p21 WAF1/CIP1 promoter compared to the other fragemts,and showed the highest affinity with the f8 fragment.In S group,the binding ability of HDAC1 to the f1 ~f10 fragment of p21 WAF1/CIP1 promoter was sig-nificantly lower than that of the control.The binding activity of HDAC1 to f8 fragment was the lowest,while reversing to reach the peak after leptin treatment.Con-clusions HDAC1canberecruitedtop21WAF1/CIP1pro-moter by the cell proliferation signal during the prolifer-ation of breast cancer MCF-7 cells.The DNA fragment from -2800 to -3200 bp in the upstream of p21 WAF1/CIP1 promoter is the target functional region for the binding with HDAC1 .
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Objective To investigate the specific sites that estrogen receptor (ER)α could be recruited to in the p21WAF1/CIP1 promoter region to regulate its transcriptional activity in MCF-7 cells,and to clarify the molecular mechanism of suberoylanilide hydroxamic acid (SAHA) and leptin in the regulation of p21WAFI/CIP1 promoter function.Methods MCF-7 cells were starved by culturing them in fetal calf serum-free medium for 24 hours,and then treated with 20 μmol/L of 0.88 μL SAHA (SAHA group) or 0.625 nmol/L of 10 μL leptin (leptin group) for 24 hours,or cultured in complete RPMI-1640 medium (control group).Cell lysates were incubated with anti-ERα antibody for ChIP analysis.The relative expression levels of DNA fragments,ranging from the TSS to upstream of the p21WAF1/CIP1 promoter region (+2 to-4 000 bp),that bound the antibody were detected by real-time PCR.Results In the control group,the relative expression levels of f1,f2,and f8 DNA fragments that bound the antiERα antibody were two-fold higher than the relative expression of the f9 fragment (P ＜ 0.01).In the SAHA and leptin groups,the relative expression of f1 to f10 DNA fragment that bound anti-ERα antibody was significantly lower than that of the control.The binding affinity of ERα for the f8 fragment was the lowest (P ＜ 0.01) in the SAHA group,and it was significantly lower than that in the leptin group (P ＜ 0.01).Conclusion ERα could be recruited to the p21WAFI/CIP1 promoter via signaling pathways activated during the proliferation of breast cancer MCF-7 cells.Moreover,the DNA fragment ranging from-2 800 to-3 200 bp upstream of the p21 WAF1/CIP1 promoter is the target functional region for high-affinity binding with ERα.
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Objective To explore the effect of p21Waf1/Cip1 methylation changes on the process of cellular senescence .Methods Bisulfite sequencing was used to analyze the methylation changes of p21Waf1/Cip1 in the process of cellular senescence;p21Waf1/Cip1 ex‐pression was detected by RT‐PCR and Western‐blot ;Middle‐aged 2BS cells was treated by 5‐aza‐CdR and cellular senescence was detected by MTT and SA‐β‐Gal staining .Results Bisulfite sequencing analysis of p21Waf1/Cip1 promoter showed that CpGs were methylated by 1 .25% in the young 2BS cells ,by 27 .27% in the middle‐aged 2BS cells ,while only by 0 .64% in the senescent cells . The expression of p21Waf1/Cip1 was low in the young(28 PD) 2BS cells ,it increased first(35 PD) but decreased later in the middle‐aged(42 PD) cells .In the senescent 2BS cells ,p21Waf1/Cip1 expression was further increased .5‐aza‐CdR treatment resulted in de‐creased growth rate but increasedβ‐Gal staining of middle‐aged 2BS cells .Conclusion The process of cellular senescence is regula‐ted by the status of p21Waf1/Cip1 methylation ,and p21Waf1/Cip1 demethylation accelerates cellular senescence .
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Objective To study the effects of artesunate(ART)on estrogen receptor negative breast cancer cell line MDA-MB-231 and its mechanisms.Methods Treated with ART for 3 days,MDA-MB-231 cells proliferation was examined by MTT assay.The morphological and uhrastructural changes of MDA-MB-231 cells were observed under microscope and electronic microscope.Immunocytochemistry was used to detect the expression of Bax,mn23,Bcl-2,and P21 WAFl/CIPl.Results ART treatment led to a dose dependent inhibition of MDA-MB-231 cells.ART could change the morphology and ultrastructure of MDA-MB-231 cens.After treatment with ART(2μmol/L)for 72 hours,immunocytochemical staining showed that the expression of Bax,nm23,and P21WAF1/CIP1 was upregulated in comparison to the control group(P0.05).Conclusions ART shows an anti-proliferative effect on MDA-MB-231 cells.The mechanisms may be related to upregnlation of Bax,nm23 and P21WAF1/CIP1 expression.
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Antitumor effects of erythromycin and the related mechanism were investigated in the present study.Neuroblastoma cells (SH-SY5Y) were exposed to erythromycin at different concentrations for different durations.Cell proliferation was measured by cell counting,and cell viability was examined by MTT assay.Cell cycle phase distribution and the cytosolic calcium level were detected by flow cytometry.Mitochondrial membrane potential was measured by the JC-1 probe staining and fluorescent microscopy.The expression of an oncogene (c-Myc) and a tumor suppressor [p21 (WAF1/Cipl)] proteins was analyzed by using Western blotting.Erythromycin could inhibit the proliferation of SH-SY5Y cells in a concentration- and time-dependent manner.The cell cycle was arrested at S phase.Mitochon drial membrane potential collapsed and the cytosolic calcium was overloaded in SH-SY5Y cells when treated with erythromycin.The expression of c-Myc protein was down-regulated,while that of p21 (WAF1/Cip1) protein was up-regulated.It was concluded that erythromycin could restrain the proliferation of SH-SY5Y cells.The antitumor mechanism of erythromycin might involve regulating the expression ofc-Myc and p21 (WAF1/Cip1) proteins.
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In this paper, we provide evidence that both the mRNA and protein levels of the cyclin-dependent kinase (CDK) inhibitor p21WAF1/CDK-interacting protein 1 (Cip1) increase upon infection of A431 cells with Vaccinia virus (VACV). In addition, the VACV growth factor (VGF) seems to be required for the gene expression because infection carried out with the mutant virus VACV-VGF- revealed that this strain was unable to stimulate its transcription. Our findings are also consistent with the notion that the VGF-mediated change in p21WAF1/Cip1 expression is dependent on tyrosine kinase pathway(s) and is partially dependent on mitogen-activated protein kinase/extracellular-signal regulated kinase 1/2. We believe that these pathways are biologically significant because VACV replication and dissemination was drastically affected when the infection was carried out in the presence of the relevant pharmacological inhibitors.
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Humans , /metabolism , Vaccinia virus/physiology , Cell Line, Tumor , /genetics , Gene Expression Regulation, Viral/genetics , Mitogen-Activated Protein Kinases/metabolism , Protein-Tyrosine Kinases/genetics , Protein-Tyrosine Kinases/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Signal Transduction/genetics , Virus Replication/geneticsABSTRACT
BACKGROUND/AIMS: Gastric carcinoma is a major cause of morbidity and mortality in Korea. It evolves through dysplasia to an invasive adenocarcinoma. The carcinogenesis of dysplasia and adenocarcinoma in the stomach was investigated by examining the levels of mutant p53 protein, p21(waf1/cip1), and cyclin D1 expression in gastric dysplasia and invasive adenocarcinoma. METHODS: Formalin- fixed paraffin-embedded tumors were examined immunohistochemically using the monoclonal antibodies to the 53 protein, p21(waf1/cip1) and cyclin D1. RESULTS: Mutant p53 protein, p21(waf1/cip1) and cyclin D1 expression were found in 66.6% (12/18), 72.2% (13/18) and 33.8% (6/18) of dysplasia, and 45.0% (9/20), 15.0% (3/20) and 30.0% (6/20) of invasive adenocarcinoma, respectively. CONCLUSIONS: These results suggest that p21(waf1/cip1), which is controlled by the p53 protein, plays a more important role in the carcinogenesis of the stomach than cyclin D1.
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Adenocarcinoma , Antibodies, Monoclonal , Carcinogenesis , Cyclin D1 , Cyclins , Korea , Mortality , StomachABSTRACT
Objective To transfect a recombinant pcDNA3.1-DCN into HepG2 cells and detect the expressions of decorin(DCN) and p21WAF1/CIP1 so as to investigate the mechanism of tumor suppression of DCN.Methods HepG2 cells were divided into pcDNA3.1-dec-HepG2 group(transfected group) and pcDNA3.1-HepG2 group(control group).After the recombinant pcDNA3.1-DCN and pcDNA3.1 were transfected into HepG2 hepatoma cells by liposome,the stably transfected cell lines were established using G418 screening.RT-PCR method was used to detect the expressions of DCN and p21WAF1/ CIP1 mRNA;Western blotting method was used to detect the expressions of DCN and p21WAF1/CIP1 protein;immunohistochemistry was performed to detect the expression of DCN protein.Results Compared with control group,the expressions of DCN and p21WAF1/CIP1 mRNA were significantly increased in transfected group by RT-PCR(P
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BACKGROUND: The effect of genistein on different types of cells has been investigated. However, its effect on the nervous system is still unclear. The aim of the present work is to explore the effect of genistein on rat neuroblastoma B35 cells. METHODS: The effect of genistein on the proliferation of B35 cells, its cytotoxicity, the cell-cycle distribution, the ultra-structural changes and the induction of apoptosis were determined using MTT assay, LDH assay, Flow-cytometric analysis, transmission electron microscopy and Hoechst staining, respectively. Furthermore, Real-time quantitative RT-PCR and Western blotting were used to examine the transcriptional and post-translational alterations of the G2/M cell-cycle arrest marker cyclin-dependent kinase inhibitor p21(waf1/cip1) and the apoptosis-related genes after genistein treatment. RESULTS: Genistein significantly inhibits cell survival, slightly elevates the release of lactate dehydrogenase and induced apoptosis in B35 cells. Genistein increased the number of cells at S-phase and induced cells to accumulate at the G2/M phase. These G2/M arrested cells are associated with a marked up-regulation of p21(waf1/cip1) at both the mRNA and protein levels. We observed that genistein up-regulates pro-apoptotic Bax with concurrent down-regulation of the anti-apoptotic Bcl-2 protein. CONCLUSION: These observations suggest that the anticancer effect of genistein on B35 neuroblastoma cells is mediated through multiple cellular pathways including G2/M cell-cycle arrest and the induction of apoptosis.
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Animals , Rats , Apoptosis , Blotting, Western , Cell Cycle Checkpoints , Cell Cycle , Cell Survival , Down-Regulation , Genistein , L-Lactate Dehydrogenase , Microscopy, Electron, Transmission , Nervous System , Neuroblastoma , Phosphotransferases , RNA, Messenger , Up-RegulationABSTRACT
PURPOSE: The p21(Waf1/Cip1) protein inhibits the cell cycle by inhibiting the phosphorylation at the G1-->S check point, and the p27(Kip1) protein similarly performs the suppressor function by controlling the p27-mediated G1 arrest. In this study, we analysed the clinical status and survival rates in correlations with p21 and p27 expression patterns in gastric cancer. MATERIALS AND METHODS: Between 1993 and 1997, 192 patients who underwent surgeries in Catholic Medical Center were analysed retrospectively in this study. Immunohistochemical staining was performed and if the nuclei of the tumor cells were stained, we assumed those as positive results. Statistical analysis was based on clinicopathological findings and differences in survival rates. RESULTS: The expression rate of p27 was 28.1% and 15.6% in p21 each. The ratio of T1-2(80.0%) was significantly high in p21 (+), but the ratio of T3-4 (50.6%) was slightly high in p21 (-). There was no statistical significance regarding other factors. The results in p27 was not much different from expression rate of p21 in T-stage. In addition, p27 expression in diffuse type (91.3%) was higher than in intestinal type (62.7%) by Lauren's classification (P <0.05). Also, there was no statistical significance in other factors. In the correlation of p21 and p27, p27 was positive when p21 was positive (53.5%). Conversely, p27 was negative when p21 was negative (76.5%, p <0.05). In the p21 and p27 combination test, there was higher rate of T1-2 (87.5%) in p21 (+)/p27 (+), and higher rate of T3-4 (58.1%) in p21 (-)/p27 (-) (P <0.05). Results showed higher rate of intestinal type (100%) in p21 (+)/p27 (+), and diffuse type (87.0%) was dominant in p21 (-)/p27 (-) (P <0.05) by Lauren's classification. Moreover, there was no statistical significance in the 5-year survival rate in the expression of p21 and p27, and the 5-year survival rate was highest in the case of p21 (+)/p27 (+) without statistical significance. CONCLUSION: In our study, p21(Waf1/Cip1) and p27(Kip1) expressed similar patterns. The expression of p21(Waf1/Cip1) and p27(Kip1) affected the degree of invasiveness of the tumor, and. Combined examination result revealed the correlation of p21(Waf1/Cip1) and p27(Kip1) with Lauren's classification and depth of invasion of the tumor. However, we assumed that little difference between the survival rates depending on expression of p21(Waf1/Cip1) and p27(Kip1) has limited their value as predictable prognostic indicators.
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Humans , Cell Cycle , Classification , Phosphorylation , Retrospective Studies , Stomach Neoplasms , Survival RateABSTRACT
Objective To determine the expression of P53 and P21 (WAF1/CIP1) in thyroid carcinomas and its relationship with development and prognosis of the carcinoma. Methods 90 cases of thyroid tissues (60 thyroid carcinomas, 10 thyroid adenomas, 10 goitres and 10 normal thyroid tissues) were studied by SP immunohistochemical method. Results Positive immunoreactivity of P53 and P21(WAF1/CIP1) was found only in thyroid carcinomas. The positive rate of the P53 and P21 is 53.3% and 41.7% respectively. The positive-staining rates of P53 were higher in cases of undifferentiated carcinomas, positive metastasis lymph nodes or in stage Ⅲ, Ⅳ than those in the cases of well-differentiated, no metastasis lymph nodes, or in stage Ⅰ,Ⅱ. In addition, the positive-staining of P21(WAF1/CIP1) were lower in cases of undifferentiated carcinomas, positive metastasis lymph nodes or stage Ⅲ, Ⅳ than that in the cases of well-differentiated, no metastasis lymph nodes or in stage Ⅰ,Ⅱ. The P21 (WAF1/CIP1) expression rate in the P53 positive group was lower than that in the P53 negative group (P<0.05). Conclusion The expression of P21(WAF1/CIP1) protein in thyroid cancer is related to P53-depend pathway and P53-independent pathway, mainly the P53-depend pathway. Examination of expression of P53 and P21 (WAF1/ CIP1) proteins may be helpful to judge the thyroid cancers behavior and prognosis.
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BACKGROUND: The p53 gene is one of a family of tumor suppressor genes that have been implicated in the genesis of a wide variety of malignant neoplasms including several epithelial tumors of the skin, and its role in oncogenesis and tumor progression is thought to be of importance. p21Waf1/Cip1 is thought to mediate p53 signaling, induced by a DNA-damaged status, to arrest the cell cycle. The mechanism that controls p21Waf1/Cip1 expression has not been clearly elucidated yet. OBJECTIVE: To evaluate the expression pattern of p53 and p21Waf1/Cip1, and their correlations in several epithelial tumors of the skin. METHOD: We investigated the expression of p53 and p21Waf1/Cip1 proteins by a immunohistoc- hemical method on the formalin-fixed, paraffin-embedded tissue specimens of squamous cell carcinoma (SCC), basal cell carcinoma (BCC), Bowen's disease, actinic keratosis (AK) and porokeratosis. RESULTS: p21Waf1/Cip1 was expressed in 50% (5/10) of SCC, 10% (1/10) of BCC, 70% (7/10) of Bowen's disease, 80% (8/10) of AK, and 40% (4/10) of porokeratosis. An increased expression of p53 was found 90% (9/10) of SCC, 70% (7/10) of BCC, 60% (6/10) of Bowen's disease, 50% (5/10) of AK, and 40% (4/10) of porokeratosis. The expression level of p53 had a significantly positive correlation with the expression level of p21Waf1/Cip1 in Bowen's disease (p = 0.045). There was no correlation observed between the expression levels of these two markers in the other diseases mentioned above (p >0.05). CONCLUSION: This data suggest that decreased p21Waf1/Cip1 expression may have a role in epithelial tumors of the skin. However, our present study indicates that there are weak interrelationship between p53, p21Waf1/Cip1, and p53-independent pathways of p21Waf1/Cip1 induction in the skin. The mechanism of how they interact to promote tumorigenesis and its prognostic values in epithelial tumors of the skin remain to be elucidated.
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Humans , Bowen's Disease , Carcinogenesis , Carcinoma, Basal Cell , Carcinoma, Squamous Cell , Cell Cycle , Genes, p53 , Genes, Tumor Suppressor , Keratosis, Actinic , Porokeratosis , SkinABSTRACT
BACKGROUND: Cell cycle progression is governed by cell cycle regulators and inhibitors such as the cyclin dependent kinases (CDK), p27(Kip1), p21(WAF1/Cip1) and p53. The purpose of this study was to correlate expressions of p34(cdc2), p27(Kip1), p21(WAF1/Cip1) and p53 with the various clinicopathologic prognostic parameters of human breast cancers. METHODS: The paraffin-embedded tissue sections from 102 patients with human breast carcinomas were examined by performing immunohistochemical staining. The primary antibodies used for immunohistochemical staining were mouse monoclonal antibody to human p34(cdc2), p27(Kip1), p21(WAF1/Cip1), p53, ER and PR. RESULTS: The expression rates of p34(cdc2), p21(WAF1/Cip1) and p53 were 29.3%, 40.2% and 49.1% in breast carcinomas, respectively. In normal breast tissues, p34(cdc2), p21(WAF1/Cip1) and p53 were not expressed. The p34(cdc2) was expressed in the cytoplasm of cancer cells. The expression rate of p27(Kip1) was 29.3% in breast carcinomas and 100% in normal breast tissues, so the loss of p27(Kip1) expression in breast cancer was noted. The high expression of p21(WAF1/Cip1) in neoplastic cells was associated with the p53 expression (p=0.03). The expression of p27(Kip1) was correlated with that of the progesterone receptor (PR) (p=0.04) and the expression of p21(WAF1/Cip1) was correlated with that of positivity for estrogen receptor (ER) (p=0.04) and PR (p=0.04). No correlation was demonstrated between the mean patient survival and the expression rate of p34(cdc2), p27(Kip1), p21(WAF1/Cip1) and p53. CONCLUSIONS: The loss of the normal cell growth cycle by the abnormal expression of cyclin dependent kinases and their inhibitors and the steroid hormones may play an important role in human breast carcinogenesis. The p53 dependent p21(WAF1/Cip1) pathway, the p27(Kip1) protein loss and the cdc2 overexpression were important in development and progression of human breast cancer.
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Animals , Humans , Mice , Antibodies , Breast Neoplasms , Breast , Carcinogenesis , Cell Cycle , Cyclin-Dependent Kinases , Cytoplasm , Estrogens , Receptors, ProgesteroneABSTRACT
p21 WAF1/CIP1 gene is known for a most important cell cycle regulator as well as its roles in apoptosis and differentiation. This review focuses on p21 WAF1/CIP1 gene functions and its association with carcinogenesis. Better understanding of the structure and function of p21 WAF1/CIP1 gene may help to comprehend molecular mechanisms of cancers and to facilitate diagnosis and treatment of malignancy.
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One of the best approaches against cancer is prevention. Inactivation of the p53 or p16INK4a genes has been extensively reported in most human cancer cells. Both p53 and p16INK4a function as tumor suppressors. Therefore, functional restoration of these molecules is considered to be one of the most useful methods for cancer prevention and therapy. We have proposed a concept termed ‘gene-regulating chemoprevention and chemotherapy’ regarding the above pathway. This concept assumes that transcriptional regulation by drugs on tumor-suppressor genes, downstream target genes or functionally similar genes (for example, family genes) of the tumor-suppressor genes would contribute to the prevention of human malignancies. Histone deacetylase (HDAC) inhibitors have been shown to be potent inducers of growth arrest, differentiation and apoptotic cell death. Previously, we demonstrated that HDAC inhibitors, such as sodium butyrate and trichostatin A (TSA), transcriptionally induce the cyclin-dependent kinase inhibitor p21WAF1/Cip1, a downstream target gene of p53, in a p53-independent manner. Furthermore, we have recently shown that HDAC inhibitors activate Gadd45, another downstream target gene of p53, and p19INK4d, a gene functionally similar to p16INK4a. Our results, taken together with previous findings, suggest that HDAC inhibitors may be one of the most attractive and promising agents for ‘gene-regulating chemoprevention’ and ‘molecular-targeting prevention’ of cancer.
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Disease Prevention , Neoplasms , Chemoprevention , GenesABSTRACT
One of the best approaches against cancer is prevention. Inactivation of the p53 or p16(INK4a) genes has been extensively reported in most human cancer cells. Both p53 and p16(INK4a) function as tumor suppressors. Therefore, functional restoration of these molecules is considered to be one of the most useful methods for cancer prevention and therapy. We have proposed a concept termed 'gene-regulating chemoprevention and chemotherapy' regarding the above pathway. This concept assumes that transcriptional regulation by drugs on tumor-suppressor genes, downstream target genes or functionally similar genes (for example, family genes) of the tumor-suppressor genes would contribute to the prevention of human malignancies. Histone deacetylase (HDAC) inhibitors have been shown to be potent inducers of growth arrest, differentiation and apoptotic cell death. Previously, we demonstrated that HDAC inhibitors, such as sodium butyrate and trichostatin A (TSA), transcriptionally induce the cyclin-dependent kinase inhibitor p21(WAF1/Cip1), a downstream target gene of p53, in a p53-independent manner. Furthermore, we have recently shown that HDAC inhibitors activate Gadd45, another downstream target gene of p53, and p19(INK4d), a gene functionally similar to p16(INK4a). Our results, taken together with previous findings, suggest that HDAC inhibitors may be one of the most attractive and promising agents for 'gene-regulating chemoprevention' and 'molecular-targeting prevention' of cancer.
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BACKGROUND: Mature cystic teratoma is a common type of ovarian tumor. Although squamous cell carcinoma (SCC) is the most common carcinoma in malignant transformations of ovarian mature cystic teratomas, SCC arising in a mature teratoma is rare. METHODS: This paper reports four cases of invasive SCC, a case of an adenosquamous cell carcinoma and a case of a pure in situ SCC arising in a mature cystic teratoma including a clinicopathological evaluation and an immunohistochemical study of the p53 protein and p21WAF1/CIP1. RESULTS: The mean age of the patients was 60 years. The sizes of the mature cystic teratomas in all cases were greater than 7.5 cm in the largest diameter. Five cases showed the nuclear accumulation of the p53 protein with no p21WAF1/CIP1 immunoreactivity. The other case showed the nuclear accumulation of p21WAF1/CIP1 without p53 expression. There was a significant inverse relationship between the p53 protein level and p21WAF1/CIP1 expression. CONCLUSION: A clinicopathological evaluation showed that a SCC arising from a mature cystic teratoma must be included in a differential diagnosis when the patient is over 42 years of age and the size of a mature cystic teratoma is greater than 75 mm in the largest diameter. It is suggested that p53 overexpression is implicated in the malignant transformation, and the p21WAF1/CIP1 expression level is dependent on alterations in the level of the p53 protein in these tumors.