Cyclin-dependent kinase 1 (CDK1) plays an essential role in cell cycle regulation.However,as mouse Cdk1embryos die early,the role of CDK1 in regulating the cell cycle and embryo development remains unclear.Here,we sho...Cyclin-dependent kinase 1 (CDK1) plays an essential role in cell cycle regulation.However,as mouse Cdk1embryos die early,the role of CDK1 in regulating the cell cycle and embryo development remains unclear.Here,we showed that zebrafish cdk1^(-/-)embryos exhibit severe microphthalmia accompanied by multiple defects in S phase entry,M phase progression,and cell differentiation but not in interkinetic nuclear migration.We identified Top2a as a potential downstream target and cyclin A2 and cyclin B1 as partners of Cdk1 in cell cycle regulation via an in silico analysis.While depletion of either cyclin A2 or Top2a led to the decreased S phase entry in zebrafish retinal cells,the depletion of cyclin B1 led to M phase arrest.Moreover,phosphorylation of Top2a at serine 1213 (S1213) was nearly abolished in both cdk1 and ccna2mutants,but not in ccnb1 mutants.Furthermore,overexpression of TOP2A^(S1213D),the phosphomimetic form of human TOP2A,rescued S phase entry and alleviated the microphthalmia defects in both cdk1^(-/-)and ccna2^(-/-)embryos.Taken together,our data suggest that Cdk1 interacts with cyclin A2 to regulate S phase entry partially through Top2a phosphorylation and interacts with cyclin B1 to regulate M phase progression.展开更多
Background： The ACTS-GC study had shown postoperative adiuvant therapy with S-1 improved survival of patients with locally advanced gastric cancer. Addition of oxaliplatin to S-1 is considered to be acceptable as one...Background： The ACTS-GC study had shown postoperative adiuvant therapy with S-1 improved survival of patients with locally advanced gastric cancer. Addition of oxaliplatin to S-1 is considered to be acceptable as one of the treatment options for gastric cancer patients after radical gastrectomy with D2 lymph node excision. Methods： We have commenced a randomized phase III trial in December 2016 to evaluate S-I plus oxaliplatin compared with S-1 alone in the adjuvant setting for locally advanced gastric cancer. A total of 564 patients will be accrued from 13 Chinese institutions in two years. The primary endpoint is 3-year relapse-free survival. The secondary endpoints are 5-year overall survival, proportion of patients who complete the postoperative chemotherapy and incidence of adverse events. Ethic and dissemination： The trial has been approved by the institutional review board of each participating institution and it was activated on December, 2016. The enrollment will be finished in December, 2018. Patient＇s follow-up will be ended until December, 2023. Trial registration： ClinicalTrials.gov, identifier： NCT02867839. Registered on August 4, 2016.展开更多
AIM： To evaluate whether the cellular proliferation rate in the large bowel epithelial cells is characterized by circadian rhythm. METHODS： Between January 2003 and December 2004, twenty patients who were diagnosed ...AIM： To evaluate whether the cellular proliferation rate in the large bowel epithelial cells is characterized by circadian rhythm. METHODS： Between January 2003 and December 2004, twenty patients who were diagnosed as suffering from primary, resectable, non-metastatic adenocarcinoma of the lower rectum, infiltrating the sphincter mechanism, underwent abdominoperineal resection, total mesorectal excision and permanent left iliac colostomy. In formalinfixed and paraffin-embedded biopsy specimens obtained from the colostomy mucosa every six hours （00：00, 06：00, 12：00, 18：00 and 24：00）, we studied the expression of G1 phase cyclins （D1 and E） as well as the expression of the G1 phase cyclin-dependent kinase （CDK） inhibitors p16 and p21 as indicators of cell cycle progres- sion in colonic epithelial cells using immunohistochemical methods. RESULTS： The expression of both cyclins showed a similar circadian fashion obtaining their lowest and highest values at 00：00 and 18：00, respectively （P〈 0.001）. A circadian rhythm in the expression of CDK inhibitor proteins p16 and p21 was also observed, with the lowest levels obtained at 12：00 and 18：00 （P〈0.001）, respectively. When the complexes cyclins D1-p21 and E-p21 were examined, the expression of the cyclins was adversely correlated to the p21 expression throughout the day. When the complexes the cyclins D1-p16 and E-p16 were examined, high levels of p16 expression were correlated to low levels of cyclin expression at 00：00, 06：00 and 24：00. Meanwhile, the highest expression levels of both cyclins were correlated to high levels of p16 expression at 18：00. CONCLUSION： Colonic epithelial cells seem to enter the G1 phase of the cell cycle during afternoon （between 12：00 and 18：00） with the highest rates obtained at 18：00. From a clinical point of view, the present results suggest that G1-phase specific anticancer therapies in afternoon might maximize their anti-tumor effect while minimizing toxicity.展开更多
Short-chain fatty acids(SCFAs)butyrate promote the postnatal rumen epithelial development and maturation in ruminants.However,molecular mechanisms of effects of butyrate on the bovine rumen epithelial cells(BRECs)prol...Short-chain fatty acids(SCFAs)butyrate promote the postnatal rumen epithelial development and maturation in ruminants.However,molecular mechanisms of effects of butyrate on the bovine rumen epithelial cells(BRECs)proliferation remain elusive.Therefore,purpose of this study was to investigate the effects of butyrate on the expression of genes and proteins at G0/G1 and S phase of BRECs cycle.Our results showed that BRECs treated with butyrate inhibited(P<0.05)the proliferation of BRECs,relatively to control.Flow cytometric assays revealed that butyrate triggers the BRECs cycle arrest at the G0/G1 phase.qRT-PCR analyses of mRNA level of genes involved in the G0/G1 phase of cell cycle showed that butyrate significantly upregulated(P<0.001)the expression of mRNA encoding p21^(Cip1)compared with control group,but it decreased(P<0.05)the mRNA levels of cyclin D1 and CDK4 genes at G0/G1 phase checkpoint compared with control.Moreover,Western blot also revealed that butyrate downregulated the expression of cyclin D3,CDK6,p-Rb,and E2F1 proteins involved in the modulation of G0/G1 phase of cell cycle.In conclusion,our results demonstrated that butyrate inhibits the proliferation of BRECs via downregulation of positive regulators at G0/G1 phase checkpoint.展开更多
Tetrahydroisoquinolines are known to have various biological effects, including antitumor activity. This study investigated the effect of 1-chloromethyl-6, 7-dimethoxy-3, 4-dihydro-1H-isoquinoline-2-sulfonic acid amid...Tetrahydroisoquinolines are known to have various biological effects, including antitumor activity. This study investigated the effect of 1-chloromethyl-6, 7-dimethoxy-3, 4-dihydro-1H-isoquinoline-2-sulfonic acid amide (CDST), a newly synthesized anticancer agent, on cellular differentiation and proliferation in HL-60 cells. Differentiation and proliferation of HL-60 cells were determined through expression of CD11b and CD14 surface antigens using flow cytometry and nitroblue tetrazolium (NBT) assay, and through analysis of cell cycle using propidium iodide staining, western blot analysis and immunoprecipitation, respectively. CDST induced the differentiation of HL-60, as shown by increased expression of differentiation surface antigen CD11b (but no significant change in CD14 expression) and increased NBT-reducing functional activity. DNA flow cytometry analysis indicated that CDST markedly induced a G0/G1 phase arrest of HL-60 cells. Subsequently, we examined the expre-ssion of G0/G1 phase cell cycle-related proteins, including cyclin-dependent kinases (CDKs), cyclins and cyclin dependent kinase inhibitors (CKIs), during the differentiation of HL-60. The levels of CDK2, CDK6, cyclin E and cyclin A were decreased, whereas steady-state levels of CDK4 and cyclin D1 were unaffected. The expression of the p27Kip1 was markedly increased by CDST, but not p21WAF1/Cip1. Moreover, CDST markedly enhanced the binding of p27Kip1 with CDK2 and CDK6, resulting in the reduced activity of both kinases. Taken together, these results demonstrate that CDST is capable of inducing cellular differentiation and growth inhibition through p27Kip1 protein-related G0/G1 phase arrest in HL-60 cells.展开更多
基金江西省自然科学基金项目(编号:20202BAB206075)江西省教育厅科技项目(编号:GJJ201202)江西中医药大学中西医结合一级学科平台(Discipline of Chinese and Western Integrative Medicine,Jiangxi University of Chinese Medicine)。
基金supported by grants from the National Key Research and Development Program of China (2017YFA0104600)the National Natural Science Foundation of China (31970767, 31771597 and 31571515)+1 种基金the National Basic Research Program of China (973 Program 2012CB966601 and 2013CB945300)the Ministry of Science and Technology of the People’s Republic of China (2011DFB30010)。
文摘Cyclin-dependent kinase 1 (CDK1) plays an essential role in cell cycle regulation.However,as mouse Cdk1embryos die early,the role of CDK1 in regulating the cell cycle and embryo development remains unclear.Here,we showed that zebrafish cdk1^(-/-)embryos exhibit severe microphthalmia accompanied by multiple defects in S phase entry,M phase progression,and cell differentiation but not in interkinetic nuclear migration.We identified Top2a as a potential downstream target and cyclin A2 and cyclin B1 as partners of Cdk1 in cell cycle regulation via an in silico analysis.While depletion of either cyclin A2 or Top2a led to the decreased S phase entry in zebrafish retinal cells,the depletion of cyclin B1 led to M phase arrest.Moreover,phosphorylation of Top2a at serine 1213 (S1213) was nearly abolished in both cdk1 and ccna2mutants,but not in ccnb1 mutants.Furthermore,overexpression of TOP2A^(S1213D),the phosphomimetic form of human TOP2A,rescued S phase entry and alleviated the microphthalmia defects in both cdk1^(-/-)and ccna2^(-/-)embryos.Taken together,our data suggest that Cdk1 interacts with cyclin A2 to regulate S phase entry partially through Top2a phosphorylation and interacts with cyclin B1 to regulate M phase progression.
基金supported by the National Science Foundation of China (No. 81374016 and 81402308)Beijing Municipal Science & Technology Commission (No. D141100000414002)
文摘Background： The ACTS-GC study had shown postoperative adiuvant therapy with S-1 improved survival of patients with locally advanced gastric cancer. Addition of oxaliplatin to S-1 is considered to be acceptable as one of the treatment options for gastric cancer patients after radical gastrectomy with D2 lymph node excision. Methods： We have commenced a randomized phase III trial in December 2016 to evaluate S-I plus oxaliplatin compared with S-1 alone in the adjuvant setting for locally advanced gastric cancer. A total of 564 patients will be accrued from 13 Chinese institutions in two years. The primary endpoint is 3-year relapse-free survival. The secondary endpoints are 5-year overall survival, proportion of patients who complete the postoperative chemotherapy and incidence of adverse events. Ethic and dissemination： The trial has been approved by the institutional review board of each participating institution and it was activated on December, 2016. The enrollment will be finished in December, 2018. Patient＇s follow-up will be ended until December, 2023. Trial registration： ClinicalTrials.gov, identifier： NCT02867839. Registered on August 4, 2016.
文摘AIM： To evaluate whether the cellular proliferation rate in the large bowel epithelial cells is characterized by circadian rhythm. METHODS： Between January 2003 and December 2004, twenty patients who were diagnosed as suffering from primary, resectable, non-metastatic adenocarcinoma of the lower rectum, infiltrating the sphincter mechanism, underwent abdominoperineal resection, total mesorectal excision and permanent left iliac colostomy. In formalinfixed and paraffin-embedded biopsy specimens obtained from the colostomy mucosa every six hours （00：00, 06：00, 12：00, 18：00 and 24：00）, we studied the expression of G1 phase cyclins （D1 and E） as well as the expression of the G1 phase cyclin-dependent kinase （CDK） inhibitors p16 and p21 as indicators of cell cycle progres- sion in colonic epithelial cells using immunohistochemical methods. RESULTS： The expression of both cyclins showed a similar circadian fashion obtaining their lowest and highest values at 00：00 and 18：00, respectively （P〈 0.001）. A circadian rhythm in the expression of CDK inhibitor proteins p16 and p21 was also observed, with the lowest levels obtained at 12：00 and 18：00 （P〈0.001）, respectively. When the complexes cyclins D1-p21 and E-p21 were examined, the expression of the cyclins was adversely correlated to the p21 expression throughout the day. When the complexes the cyclins D1-p16 and E-p16 were examined, high levels of p16 expression were correlated to low levels of cyclin expression at 00：00, 06：00 and 24：00. Meanwhile, the highest expression levels of both cyclins were correlated to high levels of p16 expression at 18：00. CONCLUSION： Colonic epithelial cells seem to enter the G1 phase of the cell cycle during afternoon （between 12：00 and 18：00） with the highest rates obtained at 18：00. From a clinical point of view, the present results suggest that G1-phase specific anticancer therapies in afternoon might maximize their anti-tumor effect while minimizing toxicity.
基金This study was supported by the National Natural Science Foundation of China(No.32002200)the Research Project of Natural Science Foundation of Jiangsu Province(BK20190898)China Agriculture Research System of MOF and MARA.
文摘Short-chain fatty acids(SCFAs)butyrate promote the postnatal rumen epithelial development and maturation in ruminants.However,molecular mechanisms of effects of butyrate on the bovine rumen epithelial cells(BRECs)proliferation remain elusive.Therefore,purpose of this study was to investigate the effects of butyrate on the expression of genes and proteins at G0/G1 and S phase of BRECs cycle.Our results showed that BRECs treated with butyrate inhibited(P<0.05)the proliferation of BRECs,relatively to control.Flow cytometric assays revealed that butyrate triggers the BRECs cycle arrest at the G0/G1 phase.qRT-PCR analyses of mRNA level of genes involved in the G0/G1 phase of cell cycle showed that butyrate significantly upregulated(P<0.001)the expression of mRNA encoding p21^(Cip1)compared with control group,but it decreased(P<0.05)the mRNA levels of cyclin D1 and CDK4 genes at G0/G1 phase checkpoint compared with control.Moreover,Western blot also revealed that butyrate downregulated the expression of cyclin D3,CDK6,p-Rb,and E2F1 proteins involved in the modulation of G0/G1 phase of cell cycle.In conclusion,our results demonstrated that butyrate inhibits the proliferation of BRECs via downregulation of positive regulators at G0/G1 phase checkpoint.
文摘Tetrahydroisoquinolines are known to have various biological effects, including antitumor activity. This study investigated the effect of 1-chloromethyl-6, 7-dimethoxy-3, 4-dihydro-1H-isoquinoline-2-sulfonic acid amide (CDST), a newly synthesized anticancer agent, on cellular differentiation and proliferation in HL-60 cells. Differentiation and proliferation of HL-60 cells were determined through expression of CD11b and CD14 surface antigens using flow cytometry and nitroblue tetrazolium (NBT) assay, and through analysis of cell cycle using propidium iodide staining, western blot analysis and immunoprecipitation, respectively. CDST induced the differentiation of HL-60, as shown by increased expression of differentiation surface antigen CD11b (but no significant change in CD14 expression) and increased NBT-reducing functional activity. DNA flow cytometry analysis indicated that CDST markedly induced a G0/G1 phase arrest of HL-60 cells. Subsequently, we examined the expre-ssion of G0/G1 phase cell cycle-related proteins, including cyclin-dependent kinases (CDKs), cyclins and cyclin dependent kinase inhibitors (CKIs), during the differentiation of HL-60. The levels of CDK2, CDK6, cyclin E and cyclin A were decreased, whereas steady-state levels of CDK4 and cyclin D1 were unaffected. The expression of the p27Kip1 was markedly increased by CDST, but not p21WAF1/Cip1. Moreover, CDST markedly enhanced the binding of p27Kip1 with CDK2 and CDK6, resulting in the reduced activity of both kinases. Taken together, these results demonstrate that CDST is capable of inducing cellular differentiation and growth inhibition through p27Kip1 protein-related G0/G1 phase arrest in HL-60 cells.
