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【Objective】 To investigate the role of RRM2 in prostate cancer and the mechanism. 【Methods】 The data of prostate cancer expression profile were downloaded from The Cancer Genome Atlas (TCGA). The correlation between RRM2 expression and clinicopathological features and prognosis of prostate cancer was analyzed. The protein expressions of RRM2 in 55 cases of prostate cancer and 38 benign tissues were determined with immunohistochemistry (IHC). The effects of RRM2 on the biological process of prostate cancer were assessed with bioinformatic analysis. The biological process of RRM2 affecting the progression of prostate cancer was verified with Western blot and flow cytometry. 【Results】 RRM2 was highly expressed in prostate cancer, and the expression was positively correlated with the clinical stage, pathological grade and metastasis of prostate cancer (P<0.05). Higher RRM2 expression predicted poorer survival. RRM2 co-expression positively correlated genes were involved in cell cycle pathways, pyrimidine nucleotide metabolism, and biological processes such as RNA transport. Cell cycle pathways were significantly enriched. RRM2 was highly correlated with CDK1 and PCNA molecules. RRM2 knockdown reduced the protein expressions of CDK1 and PCNA in DU145 and LNCap cell lines, which were arrested in the G2/M phase. 【Conclusion】 RRM2 promotes tumor progression by interfering with G2/M cycle of prostate cancer cells.
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@#Objective To analyze the expression and clinical significance of cyclin-dependent kinase 1 (CDK1) in lung adenocarcinoma by bioinformatics. Methods Based on the gene expression data of lung adenocarcinoma patients in The Cancer Genome Atlas (TCGA), the differential expression of CDK1 in lung adenocarcinoma tissues and normal lung tissues was analyzed. The expression of CDK1 gene in lung adenocarcinoma was analyzed by UALCAN at different angles. Survival analysis of different levels of CDK1 gene expression in lung adenocarcinoma was performed using Kaplan-Meier Plotter. Correlation Cox analysis of CDK1 expression and overall survival was based on clinical data of lung adenocarcinoma in TCGA. Gene set enrichment analysis was performed on gene sequences related to CDK1 expression in clinical cases. The protein interaction network of CDK1 from Homo sapiens was obtained by STRING. CDK1-related gene proteins were obtained and analyzed by the web server Gene Expression Profiling Interactive Analysis (GEPIA). Results Based on the analysis of TCGA gene expression data, CDK1 expression in lung adenocarcinoma was higher than that in normal lung tissues. UALCAN analysis showed that high CDK1 expression may be associated with smoking. Survival analysis indicated that when CDK1 gene was highly expressed, patients with lung adenocarcinoma had a poor prognosis. Univariate and multivariate Cox regression analysis of CDK1 expression and overall survival showed that high CDK1 expression was an independent risk factor for survival of patients with lung adenocarcinoma. Gene set enrichment analysis revealed that high CDK1 expression was closely related to DNA replication, cell cycle, cancer pathway and p53 signaling pathway. Conclusion CDK1 may be a potential molecular marker for prognosis of lung adenocarcinoma. In addition, CDK1 regulation may play an important role in DNA replication, cell cycle, cancer pathway and p53 signaling pathway in lung adenocarcinoma.
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The Y-located testis-specific protein Y-encoded (TSPY) and its X-homologue TSPX originated from the same ancestral gene, but act as a proto-oncogene and a tumor suppressor gene, respectively. TSPY has specialized in male-specific functions, while TSPX has assumed the functions of the ancestral gene. Both TSPY and TSPX harbor a conserved SET/NAP domain, but are divergent at flanking structures. Specifically, TSPX contains a C-terminal acidic domain, absent in TSPY. They possess contrasting properties, in which TSPY and TSPX, respectively, accelerate and arrest cell proliferation, stimulate and inhibit cyclin B-CDK1 phosphorylation activities, have no effect and promote proteosomal degradation of the viral HBx oncoprotein, and exacerbate and repress androgen receptor (AR) and constitutively active AR variant, such as AR-V7, gene transactivation. The inhibitory domain has been mapped to the carboxyl acidic domain in TSPX, truncation of which results in an abbreviated TSPX exerting positive actions as TSPY. Transposition of the acidic domain to the C-terminus of TSPY results in an inhibitory protein as intact TSPX. Hence, genomic mutations/aberrant splicing events could generate TSPX proteins with truncated acidic domain and oncogenic properties as those for TSPY. Further, TSPY is upregulated by AR and AR-V7 in ligand-dependent and ligand-independent manners, respectively, suggesting the existence of a positive feedback loop between a Y-located proto-oncogene and male sex hormone/receptors, thereby amplifying the respective male oncogenic actions in human cancers and diseases. TSPX counteracts such positive feedback loop. Hence, TSPY and TSPX are homologues on the sex chromosomes that function at the two extremes of the human oncogenic spectrum.
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The Y-located testis-specific protein Y-encoded (TSPY) and its X-homologue TSPX originated from the same ancestral gene, but act as a proto-oncogene and a tumor suppressor gene, respectively. TSPY has specialized in male-specific functions, while TSPX has assumed the functions of the ancestral gene. Both TSPY and TSPX harbor a conserved SET/NAP domain, but are divergent at flanking structures. Specifically, TSPX contains a C-terminal acidic domain, absent in TSPY. They possess contrasting properties, in which TSPY and TSPX, respectively, accelerate and arrest cell proliferation, stimulate and inhibit cyclin B-CDK1 phosphorylation activities, have no effect and promote proteosomal degradation of the viral HBx oncoprotein, and exacerbate and repress androgen receptor (AR) and constitutively active AR variant, such as AR-V7, gene transactivation. The inhibitory domain has been mapped to the carboxyl acidic domain in TSPX, truncation of which results in an abbreviated TSPX exerting positive actions as TSPY. Transposition of the acidic domain to the C-terminus of TSPY results in an inhibitory protein as intact TSPX. Hence, genomic mutations/aberrant splicing events could generate TSPX proteins with truncated acidic domain and oncogenic properties as those for TSPY. Further, TSPY is upregulated by AR and AR-V7 in ligand-dependent and ligand-independent manners, respectively, suggesting the existence of a positive feedback loop between a Y-located proto-oncogene and male sex hormone/receptors, thereby amplifying the respective male oncogenic actions in human cancers and diseases. TSPX counteracts such positive feedback loop. Hence, TSPY and TSPX are homologues on the sex chromosomes that function at the two extremes of the human oncogenic spectrum.
Subject(s)
Humans , Male , Carcinogenesis/genetics , Cell Cycle Proteins/genetics , Chromosomes, Human, Y/genetics , DNA-Binding Proteins/genetics , Proto-Oncogene Mas , Testis/metabolismABSTRACT
This study aimed to study the inhibitory activities of flavonoids on cell cycle-dependent protein kinase (CDK1)and hepatoma cells BEL-7402.The CDK1 inhibitory activity of licorice flavonoids was evaluated by CDK1 reagent kit,and antiproliferaty activity in vitro was investgated by CCK-8 assay.Subcutaneous tumor model of liver cancer Bel-7402 was established in nude mice,which were then randomly divided into drug group,posi-tive drug group and blank control group.The mice in drug group were orally administrated with licorice flavonoids for continuous 18 days. The body weight and tumor size of mice were recorded every other day.The results demonstrated that these licorice flavonoids displayed potent efficacy against CDK1,specifically,isoliquiritigenin exhibited the most potent CDK1 inhibitory activity(IC50=0.05 ± 0.005 μmol/L),which was about 6-fold more potent than positive control flavopiridol(IC50=0.29 ± 0.230 μmol/L).Molecular docking studies revealed that isoliquiritigenin engaged in six hydrogen bonds with K33,E81,L83,S84,D86,D149 in CDK1,while flavopiridol only engaged in five hydrogen bonds with E81,L83,S84,Q132,D149.In vitro biological evaluation indicated that these licorice flavonoids displayed significant antiproliferative effects on Bel-7402 cancer cells.Among them, isoliquiritigenin showed the greatest potency against Bel-7402(IC50=0.7 ± 0.11 mol/L),which was 3-fold more potent than flavopiridol(2.4 ± 0.34 mol/L).In vivo biological evaluation showed that the LD50of isoliquiritigenin was 4.38 mg/kg,and could effectively inhibit the cell growth of liver cancer Bel-7402 in mice.
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PURPOSE: The cyclin-dependent kinase 1 (Cdk1) and cyclin B complex performs important roles in the transition from the G2 to M phase in the cell cycle through removal of inhibitory phosphates on Cdk1, and Cdc25B, which is a dual-specific phosphatase, mediates these dephosphorylation events. However, measuring Cdc25B activity by existing methods is hampered by inadequate nonspecific substrates and the need to use a radiolabeled isotope. The present study aimed to develop an improved method with which to properly measure Cdc25B activity using a novel nonradioisotopic assay and Cdc25B overexpression cell lines. MATERIALS AND METHODS: A nonradioisotopic Cdk1 kinase assay, based on Western blotting for retinoblastoma protein and histone H1, was used to analyze Cdc25B activity. Also, stable Cdc25B2 and Cdc25B3 overexpression HeLa cell lines were constructed using the tetracycline-regulated expression system and were applied as a tool for screening for inhibitors of Cdc25B. RESULTS: The present study developed and optimized a nonradioisotopic assay method to properly measure Cdc25B activity. Furthermore, we constructed stable Cdc25B2 and Cdc25B3 overexpression HeLa cell lines for the establishment of a strong assay system with which to evaluate the specificity of Cdc25B inhibitors under conditions similar to the intracellular environment. These methods were confirmed as useful tools for measuring Cdc25B activity. CONCLUSION: The nonradioisotopic Cdk1 kinase assay and Cdc25B overexpression cell lines developed in this study can be conveniently used as tools for screening inhibitors of Cdc25B phosphatase as anticancer drugs.
Subject(s)
Humans , Blotting, Western , CDC2 Protein Kinase , cdc25 Phosphatases , Cell Cycle , Cell Division , Cell Line , Cyclin B , HeLa Cells , Histones , Mass Screening , Methods , Phosphates , Retinoblastoma Protein , Sensitivity and SpecificityABSTRACT
AIM:To investigate the mechanism of the radiosensitizing effect of maximum non-cytotoxic doses of tetrandrine (Tet) on nasopharyngeal carcinoma cell lines CNE1 and CNE2.METHODS:The cells were treated with maximum non-cytotoxic doses of Tet (for CNE1 cells at 1.5 μmol/L and for CNE2 cells at 1.8 μmol/L),irradiation at 4 Gy,or combination of irradiation and maximum non-cytotoxic doses of Tet.The cell cycle distribution was analyzed by flow cytometry.The protein levels of γ-H2AX,cleaved caspase-3,p-CDC25C,CDK1,p-CDK1,cyclin B1,ERK and p-ERK were determined by Western blot.RESULTS:The expression of γ-H2AX was increased in CNE1 cells and CNE2 cells after combined treatment with irradiation and maximum non-cytotoxic doses of Tet.The percentages of CNE1 cells and CNE2 cells at G2/M phase in irradiation group were (18.09 ±0.42)％ and (18.48 ± 1.32)％,respectively,which were decreased to (15.88 ± 1.04) ％ and (13.80 ± 0.82) ％ in combined treatment group,respectively (P ＜ 0.05).Combined treatment enhanced the increase in the protein level of cleaved caspase-3 caused by irradiation.The protein levels of pCDC25C and p-CDK1 were increased in a dose-dependent manner by Tet treatment (P ＜ 0.05),while the expression of CDK1 showed no difference among different doses of Tet treatments.The protein levels of p-CDC25C,p-CDK1 and CDK1 showed no difference after the treatment with maximum non-cytotoxic doses of Tet.The combined treatment with irradiation and the maximum non-cytotoxic doses of Tet decreased the protein levels of p-CDC25C and p-CDK1 (P ＜0.05),increased the expression of cyclin B1,and had no influence on the expression of CDK1 （ P ＜0.05).The combined treatment resulted in an increase in the protein level of p-ERK1 (P ＜ 0.05).CONCLUSION:The maximum non-cytotoxic doses of Tet enhance the DNA damage and apoptosis in CNE1 cells and CNE2 cells caused by irradiation,and the mechanism might be associated with ending of G2/M arrest via activation of ERK/CDC25C/CDK1/cyclin B1 pathways.
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AIM:To investigate the mechanism of the radiosensitizing effect of maximum non-cytotoxic doses of tetrandrine (Tet) on nasopharyngeal carcinoma cell lines CNE1 and CNE2.METHODS:The cells were treated with maximum non-cytotoxic doses of Tet (for CNE1 cells at 1.5 μmol/L and for CNE2 cells at 1.8 μmol/L),irradiation at 4 Gy,or combination of irradiation and maximum non-cytotoxic doses of Tet.The cell cycle distribution was analyzed by flow cytometry.The protein levels of γ-H2AX,cleaved caspase-3,p-CDC25C,CDK1,p-CDK1,cyclin B1,ERK and p-ERK were determined by Western blot.RESULTS:The expression of γ-H2AX was increased in CNE1 cells and CNE2 cells after combined treatment with irradiation and maximum non-cytotoxic doses of Tet.The percentages of CNE1 cells and CNE2 cells at G2/M phase in irradiation group were (18.09 ±0.42)％ and (18.48 ± 1.32)％,respectively,which were decreased to (15.88 ± 1.04) ％ and (13.80 ± 0.82) ％ in combined treatment group,respectively (P ＜ 0.05).Combined treatment enhanced the increase in the protein level of cleaved caspase-3 caused by irradiation.The protein levels of pCDC25C and p-CDK1 were increased in a dose-dependent manner by Tet treatment (P ＜ 0.05),while the expression of CDK1 showed no difference among different doses of Tet treatments.The protein levels of p-CDC25C,p-CDK1 and CDK1 showed no difference after the treatment with maximum non-cytotoxic doses of Tet.The combined treatment with irradiation and the maximum non-cytotoxic doses of Tet decreased the protein levels of p-CDC25C and p-CDK1 (P ＜0.05),increased the expression of cyclin B1,and had no influence on the expression of CDK1 （ P ＜0.05).The combined treatment resulted in an increase in the protein level of p-ERK1 (P ＜ 0.05).CONCLUSION:The maximum non-cytotoxic doses of Tet enhance the DNA damage and apoptosis in CNE1 cells and CNE2 cells caused by irradiation,and the mechanism might be associated with ending of G2/M arrest via activation of ERK/CDC25C/CDK1/cyclin B1 pathways.
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Aim To study the effects of cycle arrest and molecular mechanism in human leukemia HL-60 cells induced by diallyl disulfide ( DADS ) . Methods Cell count, colony formation in soft agar experiments and flow cytometry analysis were employed to observe the DADS-induced cell growth inhibition and the effect of cycle arrest in HL-60 cells. The expressions of Chk1/2 and its downstream element in HL-60 cells were detected by Western blot. Results Cell count revealed that population doubling time increased to 35. 03 h and 71. 82 h, respectively, from 19. 14 h in HL-60 cells treated with 60 and 120 μmol·L-1 DADS ( P0. 05). The expression of Cdc25C, CyclinB1 and CDK1 decreased after treated with 60 μmol·L-1 DADS in a time-dependent manner ( P0. 05 ) . Conclusion DADS can in-hibit the proliferation of HL-60 cells, and induce G2/M arrest through Chk1/Cdc25 C/CyclinB1/CDK1 path-way.
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Purpose To study the expression of p53, p21 and Cdk1/p34cdc2 in the laryngeal cancer and its margin tissues and to ex-plore their relationship with local recurrence of laryngeal cancer. Methods A total of 85 patients with early laryngeal cancer were se-lected randomly during 2004 to 2010 in Tangshan Union Hospital, Hebei, China. SP immunohistochemical method was used to detect the expression of p53, p21 and Cdk1/p34cdc2 in the tumor and margin tissues. Pathological data were collected for follow-up. Results In more than 2 years of follow-up study, 14 of 85 patients with laryngeal cancer presented with recurrence (recurrent group), while 71 patients without recurrence (none recurrent group). The positive rate of p53 protein in laryngeal cancer and its margin tissues was 60. 0% and 36. 5%, respectively, the positive rate of p21 protein in laryngeal cancer and its margin tissues was 38. 8% and 21. 2%, respectively. The positive rate of Cdk1/ p34cdc2 in laryngeal cancer and its margin tissues was 70. 6% and 29. 4%, respectively. p53 protein in the surgical margin of the recurrent group and non recurrent group was 71. 4% and 29. 6% (P = 0. 003), that of p21 was 50. 0% and 15. 5%, (P =0. 004) and Cdk1/ p34cdc2 was 57. 1% and 23. 9% (P =0. 013), respectively. There was no correlation between expression of p53 with p21 protein and Cdk1/ p34cdc2 protein(P > 0. 05). Conclusion p53, p21 and Cdk1/ p34cdc2 may be involved in the occurrence, development and recurrence of laryngeal squamous cell carcinoma. Overexpression of p53, p21 and Cdk1/ p34Cdc2 in the surgical margin is closely related to local recurrence of laryngeal cancer.
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Purpose To detect the expression of Nek2, Plk1 and Cdk1 in gastric carcinoma and to explore their correlation with clini-copathological factors. Methods We used immunohistochemistry to detect the protein expression of Nek2, Plk1 and Cdk1 in 80 cases of gastric carcinoma. Results The positive rates of Nek2, Plk1 and Cdk1 expressions in 80 cases of gastric carcinoma were 64%, 79% and 85% respectively. While the positive rates of Nek2, Plk1 and Cdk1 expressions in 20 cases normal gastric tissue were 15%, 10% and 20% respectively,with statistical significance (P0. 05). The expression of Plk1 and Cdk1 had a correlation with tumor size, differentiation of gastric cancer, invasion depth, lymph node metastasis and TNM stage (P0. 05). There were significant associations between Nek2 and Plk1, Plk1 and Cdk1, Nek2 and Cdk1 expression (P <0. 01). Conclusions Abnormal expression of Nek2, Plk1 and Cdk1 might be one of the mechanisms of tumorigenesis, especially of abnormal tumour proliferation. They may represent new potential targets for therapeutic intervention.
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Aims: A substantial part of the genome is transcribed in non-coding RNAs. We review our finding of a long non-coding RNA (designated Heg) in mononuclear cells (MNC) and regulation of TSH receptor autoantibodies (TRAb). Results: The Heg RNA transcript in MNC is negatively correlated with TRAb in patients with early and untreated Graves’ disease. In treated patients and in controls Heg correlated negatively with CD14 mRNA. Transfection studies with fragments of Heg added to MNC (exogenous Heg) decreased CD14 mRNA in MNC and increased gene expression of RIG-I, TLR7 and IFN-γ. Heg is likely to activate TLR7 receptors. CD14 is a co-receptor of TLR7. Decrease in gene expression of CD14 after Heg is a sign of differentiation of MNC to dendritic cells. This may reduce surface expression of CD14, cytokine responses and the responsiveness to TSH receptor antigens. Thus the relationship between TRAb and lnc Heg RNA is most likely explained by receptor crossinterference. Cdk1 mRNA (an index of cell cycle activity) is positively related with TRAb. Cdk1 mRNA and TRAb but not Heg decreased significantly during antithyroid treatment. Cdk1 decreased to values below normal. Conclusion: Thus both Heg RNA and Cdk1 may regulate the level of TRAb but by two different mechanisms.
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Objective To investigate the phosphorylation and dephosphorylation of CDK1 based on the specific cell cycle apoptosis in Molt-4 cells and active variety of CDK1 in cell cycle specific apoptosis.Methods The exponential phase of growth Molt-4 cells (the human acute lymphoblastic leukemia cell line) were induced with dose response and time course of Camptothecin (CPT).The specific cell cycle apoptosis was detected with API method,then cell apoptosis was verified with post sorting confocal method.Meanwhile,the phosphorylation and dephosphorylation of CDK1 were detected by the protein electrophoretic analysis (Western blot).Results The specific cell cycle apoptosis occurred on exponential phase of growth Molt-4 cells after CPT treatment.When Molt-4 cells occured S-phase apoptosis, the apoptosis cell phosphorylation of CDK1-Thr161 band was more narrow than that of control cells, the apoptosis cell phosphorylation of CDK1-Thr15 band almost had the same band with control cells.Conclusion Cell apoptosis frequently developed in different cell cycle phase. API assay is quick and efficient method to analyze specific cell cycle apoptosis. When cell apoptosis take place in S-phase,the phosphorylation activity of CDK1 is inhibited.
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Objective: To investigate the effect of oridonin on G2/M phase arrest of human stomach cancer SGC-7901 cell growth in vitro and its molecular mechanism. Methods: The inhibition of oridonin on SGC-7901 cells was detected by MTT assay. Effect of oridonin on the phase distribution of SGC-7901 cell cycle was observed by flow cytometry (FCM). Western blotting was used to analyze the expression of Cdk1 and CyclinB1. Results: IC50 of oridonin on SGC-7901 cells was 15. 64 μmol/L. The effect of oridonin on SGC-7901 cells presented the increasing percentages of cells in G2/M phase as the concentration of oridonin increased. With the increase of oridonin dose, the expression of Cdk1 and CyclinB1 proteins was remarkably decreased. Conclusion: Oridonin can down-regulate the expression of Cdk1 and CyclinB1, which may be the mechanism of arresting SGC-7901 cells in G2/M phase.
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Aim To explore the effects of the Melittin on growth and cell cycle of SGC-7901 cells.Methods Growth inhibition effect of Melittin was evaluated using SRB in SGC-7901 cells in vitro;Melittin induced cell cycle arrest was investigated using flow cytometry assay;reverse transcription PCR(RT-PCR)was used to detect the associated protein mRNA of cell cycle.Results Proliferation activity of SGC-7901 cells was inhibited after treatment with Melittin(1,2,4,8,16,32×10~(-3) μg·L~(-1))(P<0.05 or P<0.01)for 24 h;Flowcytometry analysis revealed that SGC-7901 cells accumulated in the G_2/M phase after treatment with Melittin(4,8×10~(-3) μg·L~(-1))for 24 h;the expression of CylinB1,CDK1 and Cdc25c mRNA were decreased.Conclutions Proliferation activity of SGC-7901 cells was inhibited by Melittin,which may be related to the inhibitory effect of Melittin on associated protein transcription in the G_2/M stage of SGC-7901 cells.
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Objective:To investigate the mechanisms of genistein (GEN) affecting the chemosen- sitivity of human breast cancer cell line MDA-MB-453 to paclitaxel (PTX) in vitro. Method:HER2/neu- overexpressing breast cancer cells MDA-MB-453 were treated by GEN, PTX alone or combined in vitro. Cell cycle was measured by flow cytometry. The expression of HER2/neu protein was observed by immunocytochemistry and. Akt, p-Akt, cyclin B1 and CDK1 protein by Western blot. Results:Cell cycle of MDA-MB-453 cells was blocked at G1/S after treatment of GEN, while at G2/M after treatment with PTX alone. Both GEN and PTX did not change the expression of HER2/neu, total Akt and CDK1 in MDA-MB-453 cells, but GEN significantly decreased p-Akt and cyclin B1 level, and PTX obviously increased cyclinB1 level. GEN antagonized the effects of PTX on level of cyclin B1 protein and blockage of G2/M in MDA-MB-453 cells after treatment with GEN and PTX in combination. Conclusion:The antagonism effects of GEN on the increase of cyclin B1 and blockage of G2/M induced by PTX may be one of the mechanisms of GEN affecting the chemosensitivity of MDA-MB-453 cells to PYX.