Objective Cucurbitacins are the highly oxygenated tetracyclic triterpenes,which are predominantly found in the Cucurbitaceae family but are also present in several other families of the plant kingdom.A number of compo...Objective Cucurbitacins are the highly oxygenated tetracyclic triterpenes,which are predominantly found in the Cucurbitaceae family but are also present in several other families of the plant kingdom.A number of compounds of this group have been investigated for their cytotoxic,hepatoprotective,anti-inflammatory,cardiovascular and anti-diabetic activities.In China,the cucurbitacin preparation,which contains mostly cucurbitacin B and cucurbitacin E,has been clinically used for the treatment of the primary liver carcinoma.It has been previously reported that cucurbitacin E could produce cytotoxicity against a variety of cancer cells,and various mechanisms were implicated in its cytotoxic effect.The present study is to investigate the effect of cucurbitacin E on hepatoma cells in vitro and in vivo and to study their potential mechanisms of action.Methods The MTT assay was used to assess the viability of human HepG2 and BEL7402 hepatoma cells in vitro after treatment with different concentrations of cucurbitacin E.The cell cycle distribution was determined by flowcytometric analysis after propidium iodide(PI)staining.The cell cycle-related proteins were detected using western blotting analysis.Implanted mouse hepatoma H22 model was built to evaluate the growth inhibitory effect of cucurbitacin E in vivo in mice.Results Our studies found that cucurbitacin E(10-300 nM)produced anti-proliferative effect on human HepG2 and BEL7402 hepatoma cells in vitro without cytotoxicity.According to flowcytometric analysis,cucurbitacin E arrested the cell cycle at G2/M phase in both HepG2 and BEL7402 hepatoma cells after 24 h treatment.Cucurbitacin E induced the decrease in the level of CDK1 protein and the increase in the level of p21 protein,but had no effect on the levels of cyclin A,cyclin B1 and Cdc25C protein.In in vivo anti-tumor experiment,cucurbitacin E had significant inhibitory effects on the growth of mouse H22 hepatoma cells.Conclusions Cucurbitacin E inhibited the proliferation of hepatoma cells in vitro and in vivo,at least in part,through induction of cell cycle arrest at G2/M phase,which was mediated by concomitant upregulation of p21 and downregulation of CDK1.We consider that cucurbitacin E may be useful in the treatment of liver cancer.展开更多
Objective Flavans are a set of naturally occurring flavonoids possessing a 2-phenylchroman nucleus,which are widely distributed in the plant kingdom.A number of flavan compounds exhibit antitumor activities.In our pre...Objective Flavans are a set of naturally occurring flavonoids possessing a 2-phenylchroman nucleus,which are widely distributed in the plant kingdom.A number of flavan compounds exhibit antitumor activities.In our previous report,a straightforward synthetic procedure for 2(±)-7,8,3',4',5'-pentamethoxyflavan(PMF)was developed.To be more important,PMF showed growth inhibitory effect on various human tumor cell lines,especially against HL60 cells.In the present study,we aim to investigate the molecular mechanisms of action of PMF in HL60 cells.This is the first report of the molecular mechanisms on anti-tumor effect of flavan compounds.Methods Trypan blue exclusion experiment was used for cell growth inhibition assay.Cell apoptosis,cell cycle distribution and the mitochondrial membrane potential(MMP)were assessed by flowcytometric analysis after AO/EB,PI and Rh123 flurescence staining,respectively.Cell cycle-and apoptosis-related proteins were detected using western blotting analysis.Results PMF(1-30 μM)inhibited the growth of HL60 cells in a time-and concentration-dependent manner.Antiproliferative effect of PMF on HL60 cells was associated with G2/M cell cycle arrest,which was mediated by regulating the expression of p21,Cdc25C and cyclin A proteins and inhibiting the phosphorylation of Cdc2 at Thr161.The prolonged PMF treatment also induced apoptosis of HL60 cells,which was characterized by DNA fragmentation,cleavage of poly(ADP-ribose)polymerase,caspase-3,caspase-8 and caspase-9,changes of Bcl-2 and Bax expression and a decrease in the mitochondrial membrane potential(MMP).Furthermore,caspase-3 inhibitor,not caspase-8 inhibitor and caspase-9 inhibitor,completely blocked PMF-caused apoptosis.Conclusions PMF inhibited the growth of HL60 cells via induction of G2/M arrest and apoptosis.Blockade of cell cycle was associated with the downregulation of Cdc2 complex activity.Both death receptor and mitochondrial apoptotic pathways explained PMF-caused apoptosis.展开更多
Objective： Squamous esophageal carcinoma is highly prevalent in developing countries, especially in China. Tu Bei Mu （TBM）, a traditional folk medicine, has been used to treat esophageal squamous cell carcinoma （E...Objective： Squamous esophageal carcinoma is highly prevalent in developing countries, especially in China. Tu Bei Mu （TBM）, a traditional folk medicine, has been used to treat esophageal squamous cell carcinoma （ESCC） for a long term. tubeimoside I （TBMS1） is the main component of TBM, exhibiting great anticancer potential. In this study, we investigated the mechanism of TBMS1 cytotoxic effect on EC109 cells. Methods： Comparative nuclear proteomic approach was applied in the current study and we identified several altered protein spots. Further biochemical studies were carried out to detect the mitochondrial membrane potential, cell cycle and corresponding proteins＇ expression and location. Results： Subcellular proteomic study in the nucleus from EC109 cells revealed that altered proteins were associated with mitochondrial function and cell proliferation. Further biochemical studies showed that TBMSl-induced molecular events were related to mitochondria-induced intrinsic apoptosis and P21-cyclin B 1/cdc2 complex-related G2/M cell cycle arrest. Conclusions： Considering the conventional application of TBM in esophageal cancer, TBMS1 therefore may have a great potential as a chemotherapeutic drug candidate for ESCC.展开更多
OBJECTIVE Chronic kidney disease(CKD)has become a global public health problem with 10%-15%incidence rate,and inhibiting the renal interstitial fibrosis is considered to be a potential strategy to delay the progressio...OBJECTIVE Chronic kidney disease(CKD)has become a global public health problem with 10%-15%incidence rate,and inhibiting the renal interstitial fibrosis is considered to be a potential strategy to delay the progression of CKD.Z-Guggulsterone(Z-GS),an active compound from derived from Commiphora mukul,has been proved to be effective in various diseases.The present study aimes to determine the protective effect and the molecular mechanism of Z-GS on renal fibrosis.METHODS Unilateral ureteral obstruction(UUO)mice and hypoxia-induced HK-2 cells were used to simulate renal fibrosis in vitro and in vivo,respectively.The mice and cells were treated with different doses of Z-GS to observe the pharmacological action.Renal function,including Scr,BUN,and UA,were detected by commercial kits.H&E and Masson staining were performed to observe histopathological changes of kidney.Cell viability and LDH release of HK-2 cells were detected by commercial kits.Cell cycle distribution and apoptosis rate were analyzed by flow cytometry.Fibrosis markers were detected by immunohistochemistry and immunofluorescence analysis.Cell cycle related proteins and Klotho/p53 signaling were analyzed by Western blotting.RESULTS The results showed that Z-GS decreased the rise of Scr,BUN,and UA and lightened renal histopathological injury,which were induced by UUO.Besides,Z-GS administration alleviated renal fibrosis in mice by inhibiting the expressions ofα-SMA,TGF-βand collagenⅣ,and delayed G2/M cell cycle arrest by promoting the expressions of CDK1 and cyclinD1/B1 rate.Experiments in vitro indicated that Z-GS treatment significantly increased the cell viability while decreased the LDH release in hypoxia-induced HK-2 cells.In addition,hypoxia induced fibrosis and G2/M cycle arrest in HK-2 cells were retarded by Z-GS.The study of its possible mechanism exhibited that Z-GS treatment increased the level of Klotho and inhibited P53 level.Nevertheless,the effect of Z-GS on Klotho/P53 signaling was reversed by siRNA-Klotho.Moreover,siRNA-Klotho treatment eliminated the effects of Z-GS on G2/M cell cycle arrest and fibrosis.CONCLUSION This study clarified that Z-GS alleviated renal fibrosis and G2/M cycle arrest through Klotho/P53 signaling pathway.People who have suffered CKD may potentially benefit from treatment with Z-GS.展开更多
As a cell cycle regulator, the Myb-related CDC5 protein was reported to be essential for the G2 phase of the cell cycle in yeast and animals, but little is known about its function in plants. Here we report the functi...As a cell cycle regulator, the Myb-related CDC5 protein was reported to be essential for the G2 phase of the cell cycle in yeast and animals, but little is known about its function in plants. Here we report the functional characterization of the CDC5 gene in Arabidopsis thaliana. Arabidopsis CDC5 （AtCDC5） is mainly expressed in tissues with high cell division activity, and is expressed throughout the entire process of embryo formation. The AtCDC5 loss-of-function mutant is embryonic lethal. In order to investigate the function of AtCDC5 in vivo, we generated AtCDC5-RNAi plants in which the expression of AtCDC5 was reduced by RNA interference. We found that the G2 to M （G2/M） phase transition was affected in the AtCDC5-RNAi plants, and that endoreduplication was increased. Additionally, the maintenance of shoot apical meristem （SAM） function was disturbed in the AtCDC5-RNAi plants, in which both the WUSCHEL （WUS）- CLAVATA （CLV） and the SHOOT MERISTEMLESS （STM） pathways were impaired. In situ hybridization analysis showed that the expression of STMwas greatly reduced in the shoot apical cells of the AtCDC5-RNAi plants. Moreover, cyclinB1 or Histone4 was found to be expressed in some of these cells when the transcript of STM was undetectable. These results suggest that AtCDC5 is essential for the G2/M phase transition and may regulate the function of SAM by controlling the expression ofSTMand WUS.展开更多
Objective To explore the role of p21 in ionizing radiation-induced changes in protein levels during the G2/M transition and long-term G2 arrest.Methods Protein expression levels were assessed by western blot in the hu...Objective To explore the role of p21 in ionizing radiation-induced changes in protein levels during the G2/M transition and long-term G2 arrest.Methods Protein expression levels were assessed by western blot in the human uveal melanoma 92-1 cells after treatment with ionizing radiation.Depletion of p21 was carried out by employing the siR NA technique.Cell cycle distribution was determined by flow cytometry combined with histone H3 phosphorylation at Ser28,an M-phase marker.Senescence was assessed by senescenceassociated-β-galactosidase（SA-β-gal） staining combined with Ki67 staining,a cell proliferation marker.Results Accompanying increased p21,the protein levels of G2/M transition genes declined significantly in 92-1 cells irradiated with 5 Gy of X-rays.Furthermore,these irradiated cells were blocked at the G2 phase followed by cellular senescence.Depletion of p21 rescued radiation-induced G2 arrest as demonstrated by the upregulation of G2/M transition kinases,as well as the high expression of histone H3 phosphorylated at Ser28.Knockdown of p21 resulted in entry into mitosis of irradiated 92-1 cells.However,cells with serious DNA damage failed to undergo cytokinesis,leading to the accumulation of multinucleated cells.Conclusion Our results indicated that p21 was responsible for the downregulation of G2/M transition regulatory proteins and the bypass of mitosis induced by irradiation.Downregulation of p21 by siR NA resulted in G2-arrested cells entering into mitosis with serious DNA damage.This is the first report on elucidating the role of p21 in the bypass of mitosis.展开更多
Objective: To study cell cycle retardation, apoptosis and the expression of antioncogene p57kip2 by radioactive rays in nasopharyngeal carcinoma cells. Methods: Cell cycle retardation, apoptosis and cell survival rate...Objective: To study cell cycle retardation, apoptosis and the expression of antioncogene p57kip2 by radioactive rays in nasopharyngeal carcinoma cells. Methods: Cell cycle retardation, apoptosis and cell survival rate induced by radioac- tive rays were tested by the methods of flow cytometry and MTT method. The expression of antioncogene p57kip2 was detected by immunohistochemistry and Western blot. Results: After irradiation, G1 phase had no obvious retardation, S phase showed transient delay. There was a positive correlation between irradiation dosage and retardation strength in G2/M phase (P < 0.01). Peak value appeared at 24 h after 12 Gy irradiation, then decreased. There was a positive correlation between apop- tosis incidence and irradiation dosage or after-irradiation time extention (P < 0.01). There was a negative correlation between cell survival rate and irradiation dosage or apoptosis incidence (P < 0.01). The expression of p57kip2 protein was up-regulated along with the prolongation of time and dosage after irradiation (P < 0.01). Conclusion: G2/M phase arrest, apoptosis and the up-regulation of the expression of p57kip2 protein all can reflect predict the radiosensitivity of nasopharyngeal carcinoma cells.展开更多
Objective:To investigate the effects and mechanisms of genistein on the gene expression in the Wnt pathway in acute leukemia(AL)cells.Methods:The expression of Wnt pathway genes and cell cycle-related genes were analy...Objective:To investigate the effects and mechanisms of genistein on the gene expression in the Wnt pathway in acute leukemia(AL)cells.Methods:The expression of Wnt pathway genes and cell cycle-related genes were analyzed in two AL cell lines.Pyrophosphate sequencing was performed to determine the methylation degree.Then,the enrichment of H4K20mel and H3K9ac was determined using ChIP-qPCR.Flow cytometry was used to analyze the cell cycle.Results:The IC_(50) of genistein in the two AL cell lines was lower than that for the bone marrow mesenchymal stem cell line.Genistein upregulated H4K20mel,KMT5A and Wnt suppressor genes,including Wnt5a,and downregulated the downstream target genes of Wnt,such as c-myc and β-catenin.The methylation degree and H3K9ac enrichment in the Wnt5a promoter region remained unchanged.However,the enrichment of H4K20mel in the Wnt5a promoter and coding regions increased.In addition,genistein upregulated Phospho-cdc2,Mytl,Cyclin A,Cyclin E2,p21 and Phospho-histone H3,but downregulated Phospho-weel.Cell cycle arrest was induced in the G2/M phase.Conclusion:Genistein inhibits the activation of the Wnt pathway by promoting the expression of Wnt5a through the activation of KMT5A and enrichment of H4K20mel in the Wnt5a gene promoter and coding regions,rather than demethylation.Genistein also blocks the cell cycle in the G2/M phase.Therefore,genistein is a potential anti-leukemia drug.展开更多
文摘Objective Cucurbitacins are the highly oxygenated tetracyclic triterpenes,which are predominantly found in the Cucurbitaceae family but are also present in several other families of the plant kingdom.A number of compounds of this group have been investigated for their cytotoxic,hepatoprotective,anti-inflammatory,cardiovascular and anti-diabetic activities.In China,the cucurbitacin preparation,which contains mostly cucurbitacin B and cucurbitacin E,has been clinically used for the treatment of the primary liver carcinoma.It has been previously reported that cucurbitacin E could produce cytotoxicity against a variety of cancer cells,and various mechanisms were implicated in its cytotoxic effect.The present study is to investigate the effect of cucurbitacin E on hepatoma cells in vitro and in vivo and to study their potential mechanisms of action.Methods The MTT assay was used to assess the viability of human HepG2 and BEL7402 hepatoma cells in vitro after treatment with different concentrations of cucurbitacin E.The cell cycle distribution was determined by flowcytometric analysis after propidium iodide(PI)staining.The cell cycle-related proteins were detected using western blotting analysis.Implanted mouse hepatoma H22 model was built to evaluate the growth inhibitory effect of cucurbitacin E in vivo in mice.Results Our studies found that cucurbitacin E(10-300 nM)produced anti-proliferative effect on human HepG2 and BEL7402 hepatoma cells in vitro without cytotoxicity.According to flowcytometric analysis,cucurbitacin E arrested the cell cycle at G2/M phase in both HepG2 and BEL7402 hepatoma cells after 24 h treatment.Cucurbitacin E induced the decrease in the level of CDK1 protein and the increase in the level of p21 protein,but had no effect on the levels of cyclin A,cyclin B1 and Cdc25C protein.In in vivo anti-tumor experiment,cucurbitacin E had significant inhibitory effects on the growth of mouse H22 hepatoma cells.Conclusions Cucurbitacin E inhibited the proliferation of hepatoma cells in vitro and in vivo,at least in part,through induction of cell cycle arrest at G2/M phase,which was mediated by concomitant upregulation of p21 and downregulation of CDK1.We consider that cucurbitacin E may be useful in the treatment of liver cancer.
文摘Objective Flavans are a set of naturally occurring flavonoids possessing a 2-phenylchroman nucleus,which are widely distributed in the plant kingdom.A number of flavan compounds exhibit antitumor activities.In our previous report,a straightforward synthetic procedure for 2(±)-7,8,3',4',5'-pentamethoxyflavan(PMF)was developed.To be more important,PMF showed growth inhibitory effect on various human tumor cell lines,especially against HL60 cells.In the present study,we aim to investigate the molecular mechanisms of action of PMF in HL60 cells.This is the first report of the molecular mechanisms on anti-tumor effect of flavan compounds.Methods Trypan blue exclusion experiment was used for cell growth inhibition assay.Cell apoptosis,cell cycle distribution and the mitochondrial membrane potential(MMP)were assessed by flowcytometric analysis after AO/EB,PI and Rh123 flurescence staining,respectively.Cell cycle-and apoptosis-related proteins were detected using western blotting analysis.Results PMF(1-30 μM)inhibited the growth of HL60 cells in a time-and concentration-dependent manner.Antiproliferative effect of PMF on HL60 cells was associated with G2/M cell cycle arrest,which was mediated by regulating the expression of p21,Cdc25C and cyclin A proteins and inhibiting the phosphorylation of Cdc2 at Thr161.The prolonged PMF treatment also induced apoptosis of HL60 cells,which was characterized by DNA fragmentation,cleavage of poly(ADP-ribose)polymerase,caspase-3,caspase-8 and caspase-9,changes of Bcl-2 and Bax expression and a decrease in the mitochondrial membrane potential(MMP).Furthermore,caspase-3 inhibitor,not caspase-8 inhibitor and caspase-9 inhibitor,completely blocked PMF-caused apoptosis.Conclusions PMF inhibited the growth of HL60 cells via induction of G2/M arrest and apoptosis.Blockade of cell cycle was associated with the downregulation of Cdc2 complex activity.Both death receptor and mitochondrial apoptotic pathways explained PMF-caused apoptosis.
基金supported by the Natural Science Foundation of Fujian Province of China (No. 2011J05098)the Fundamental Research Funds for the Central Universities (No. 2011121055)+1 种基金Grants from the National Natural Science Foundation of China (No. 81202956)SRF for ROCS, SEM [2011]1568 and NSFC (No. 81102332)
文摘Objective： Squamous esophageal carcinoma is highly prevalent in developing countries, especially in China. Tu Bei Mu （TBM）, a traditional folk medicine, has been used to treat esophageal squamous cell carcinoma （ESCC） for a long term. tubeimoside I （TBMS1） is the main component of TBM, exhibiting great anticancer potential. In this study, we investigated the mechanism of TBMS1 cytotoxic effect on EC109 cells. Methods： Comparative nuclear proteomic approach was applied in the current study and we identified several altered protein spots. Further biochemical studies were carried out to detect the mitochondrial membrane potential, cell cycle and corresponding proteins＇ expression and location. Results： Subcellular proteomic study in the nucleus from EC109 cells revealed that altered proteins were associated with mitochondrial function and cell proliferation. Further biochemical studies showed that TBMSl-induced molecular events were related to mitochondria-induced intrinsic apoptosis and P21-cyclin B 1/cdc2 complex-related G2/M cell cycle arrest. Conclusions： Considering the conventional application of TBM in esophageal cancer, TBMS1 therefore may have a great potential as a chemotherapeutic drug candidate for ESCC.
基金National Natural Science Foundation of China(82003982)Natural Science Foundation of Gansu Province(20JR5RA591+1 种基金20JR10R015)and Special Cultivation Project of the 940th Hospital(2021yxky026)。
文摘OBJECTIVE Chronic kidney disease(CKD)has become a global public health problem with 10%-15%incidence rate,and inhibiting the renal interstitial fibrosis is considered to be a potential strategy to delay the progression of CKD.Z-Guggulsterone(Z-GS),an active compound from derived from Commiphora mukul,has been proved to be effective in various diseases.The present study aimes to determine the protective effect and the molecular mechanism of Z-GS on renal fibrosis.METHODS Unilateral ureteral obstruction(UUO)mice and hypoxia-induced HK-2 cells were used to simulate renal fibrosis in vitro and in vivo,respectively.The mice and cells were treated with different doses of Z-GS to observe the pharmacological action.Renal function,including Scr,BUN,and UA,were detected by commercial kits.H&E and Masson staining were performed to observe histopathological changes of kidney.Cell viability and LDH release of HK-2 cells were detected by commercial kits.Cell cycle distribution and apoptosis rate were analyzed by flow cytometry.Fibrosis markers were detected by immunohistochemistry and immunofluorescence analysis.Cell cycle related proteins and Klotho/p53 signaling were analyzed by Western blotting.RESULTS The results showed that Z-GS decreased the rise of Scr,BUN,and UA and lightened renal histopathological injury,which were induced by UUO.Besides,Z-GS administration alleviated renal fibrosis in mice by inhibiting the expressions ofα-SMA,TGF-βand collagenⅣ,and delayed G2/M cell cycle arrest by promoting the expressions of CDK1 and cyclinD1/B1 rate.Experiments in vitro indicated that Z-GS treatment significantly increased the cell viability while decreased the LDH release in hypoxia-induced HK-2 cells.In addition,hypoxia induced fibrosis and G2/M cycle arrest in HK-2 cells were retarded by Z-GS.The study of its possible mechanism exhibited that Z-GS treatment increased the level of Klotho and inhibited P53 level.Nevertheless,the effect of Z-GS on Klotho/P53 signaling was reversed by siRNA-Klotho.Moreover,siRNA-Klotho treatment eliminated the effects of Z-GS on G2/M cell cycle arrest and fibrosis.CONCLUSION This study clarified that Z-GS alleviated renal fibrosis and G2/M cycle arrest through Klotho/P53 signaling pathway.People who have suffered CKD may potentially benefit from treatment with Z-GS.
基金Acknowledgments The authors thank Dr Liying Du （Peking University, China） for technical help on the flow cytometric analysis. The authors also thank Dr Zhongchi Liu （University of Maryland, USA）, Dr Chun-Ming Liu （Institute of Botany CAS, China）, Dr Terry Matthew （University of Southampton, UK）, Professor Daochun Kong （Peking University, China） and Dr Naomi Nakayama （Yale University, USA） for critical comments and valuable discussion. This work was supported by the National Natural Science Foundation of China （GN 30625002 to L-J Qu）.
文摘As a cell cycle regulator, the Myb-related CDC5 protein was reported to be essential for the G2 phase of the cell cycle in yeast and animals, but little is known about its function in plants. Here we report the functional characterization of the CDC5 gene in Arabidopsis thaliana. Arabidopsis CDC5 （AtCDC5） is mainly expressed in tissues with high cell division activity, and is expressed throughout the entire process of embryo formation. The AtCDC5 loss-of-function mutant is embryonic lethal. In order to investigate the function of AtCDC5 in vivo, we generated AtCDC5-RNAi plants in which the expression of AtCDC5 was reduced by RNA interference. We found that the G2 to M （G2/M） phase transition was affected in the AtCDC5-RNAi plants, and that endoreduplication was increased. Additionally, the maintenance of shoot apical meristem （SAM） function was disturbed in the AtCDC5-RNAi plants, in which both the WUSCHEL （WUS）- CLAVATA （CLV） and the SHOOT MERISTEMLESS （STM） pathways were impaired. In situ hybridization analysis showed that the expression of STMwas greatly reduced in the shoot apical cells of the AtCDC5-RNAi plants. Moreover, cyclinB1 or Histone4 was found to be expressed in some of these cells when the transcript of STM was undetectable. These results suggest that AtCDC5 is essential for the G2/M phase transition and may regulate the function of SAM by controlling the expression ofSTMand WUS.
基金supported by the National Natural Science Foundation of China[No.U1232125,31270895]the International Science&Technology Cooperation Program of China[No.2015DFR30940]
文摘Objective To explore the role of p21 in ionizing radiation-induced changes in protein levels during the G2/M transition and long-term G2 arrest.Methods Protein expression levels were assessed by western blot in the human uveal melanoma 92-1 cells after treatment with ionizing radiation.Depletion of p21 was carried out by employing the siR NA technique.Cell cycle distribution was determined by flow cytometry combined with histone H3 phosphorylation at Ser28,an M-phase marker.Senescence was assessed by senescenceassociated-β-galactosidase（SA-β-gal） staining combined with Ki67 staining,a cell proliferation marker.Results Accompanying increased p21,the protein levels of G2/M transition genes declined significantly in 92-1 cells irradiated with 5 Gy of X-rays.Furthermore,these irradiated cells were blocked at the G2 phase followed by cellular senescence.Depletion of p21 rescued radiation-induced G2 arrest as demonstrated by the upregulation of G2/M transition kinases,as well as the high expression of histone H3 phosphorylated at Ser28.Knockdown of p21 resulted in entry into mitosis of irradiated 92-1 cells.However,cells with serious DNA damage failed to undergo cytokinesis,leading to the accumulation of multinucleated cells.Conclusion Our results indicated that p21 was responsible for the downregulation of G2/M transition regulatory proteins and the bypass of mitosis induced by irradiation.Downregulation of p21 by siR NA resulted in G2-arrested cells entering into mitosis with serious DNA damage.This is the first report on elucidating the role of p21 in the bypass of mitosis.
文摘Objective: To study cell cycle retardation, apoptosis and the expression of antioncogene p57kip2 by radioactive rays in nasopharyngeal carcinoma cells. Methods: Cell cycle retardation, apoptosis and cell survival rate induced by radioac- tive rays were tested by the methods of flow cytometry and MTT method. The expression of antioncogene p57kip2 was detected by immunohistochemistry and Western blot. Results: After irradiation, G1 phase had no obvious retardation, S phase showed transient delay. There was a positive correlation between irradiation dosage and retardation strength in G2/M phase (P < 0.01). Peak value appeared at 24 h after 12 Gy irradiation, then decreased. There was a positive correlation between apop- tosis incidence and irradiation dosage or after-irradiation time extention (P < 0.01). There was a negative correlation between cell survival rate and irradiation dosage or apoptosis incidence (P < 0.01). The expression of p57kip2 protein was up-regulated along with the prolongation of time and dosage after irradiation (P < 0.01). Conclusion: G2/M phase arrest, apoptosis and the up-regulation of the expression of p57kip2 protein all can reflect predict the radiosensitivity of nasopharyngeal carcinoma cells.
基金supported by grants from the National Natural Science Foundation of China(No.81800167)the Natural Science Foundation of Fujian Province(No.2017J05132)+4 种基金the Fujian Provincial Health Technology Project(No.2018-ZQN-40)the Start-up Fund Project of Fujian Medical University(No.2016QH020)the Construction Project of Fujian Medical Center of Hematology(No.Min201704)the National and Fujian Provincial Key Clinical Specialty Discipline Construction Program,ChinaClinical Research Center for Hematological Malignancies of Fujian Province.
文摘Objective:To investigate the effects and mechanisms of genistein on the gene expression in the Wnt pathway in acute leukemia(AL)cells.Methods:The expression of Wnt pathway genes and cell cycle-related genes were analyzed in two AL cell lines.Pyrophosphate sequencing was performed to determine the methylation degree.Then,the enrichment of H4K20mel and H3K9ac was determined using ChIP-qPCR.Flow cytometry was used to analyze the cell cycle.Results:The IC_(50) of genistein in the two AL cell lines was lower than that for the bone marrow mesenchymal stem cell line.Genistein upregulated H4K20mel,KMT5A and Wnt suppressor genes,including Wnt5a,and downregulated the downstream target genes of Wnt,such as c-myc and β-catenin.The methylation degree and H3K9ac enrichment in the Wnt5a promoter region remained unchanged.However,the enrichment of H4K20mel in the Wnt5a promoter and coding regions increased.In addition,genistein upregulated Phospho-cdc2,Mytl,Cyclin A,Cyclin E2,p21 and Phospho-histone H3,but downregulated Phospho-weel.Cell cycle arrest was induced in the G2/M phase.Conclusion:Genistein inhibits the activation of the Wnt pathway by promoting the expression of Wnt5a through the activation of KMT5A and enrichment of H4K20mel in the Wnt5a gene promoter and coding regions,rather than demethylation.Genistein also blocks the cell cycle in the G2/M phase.Therefore,genistein is a potential anti-leukemia drug.
