结肠癌细胞系SW480对不同化疗药物化疗敏感性的研究(英文)

Objective:The aim of this study was to investigate the sensitivity of chemotherapeutic agents 5-FU,cisplatin(DDP) or TAXOL on colon cancer cell line SW480 with different methods,to find out the best examine time period for further study of chemotherapeutic sensitivities.Methods:The SW480 cell was treated with 5-FU(200μg/mL),DDP(150μg/mL) or TAXOL(50μg/mL) respectively for 4h,8h or 12h.MTT assay was used to examine the cell survival rate,Annexin V/PI assay was used to analysis the apoptosis rate,Western Blot assay was applied to examine the expression of apoptotic protein.Results:(1) Results of MTT assay showed that the survival rate of SW480 cells at 4h,8h or 12h was:5-FU(200μg/mL)96.0%±8.2%,85.4%±7.8%,74.4% ±10.2%(P<0.05);DDP(150μg/mL) 99.0%±6.4%,88.7%±4.7%(P<0.05),46.9%±2.6%(P<0.01);TAXOL(50μg/mL) 51.5%±4.2%(P<0.01),31.9%±3.1%,17.6%±2.3%,or blank group 97.2%±5.8%,98.7%±7.2%,97.5%±7.5% respectively.(2) The apoptosis rate of cancer cells at 4h,8h or 12h was:control group:3.4%±0.2%,6.2%±0.4%,7.0%±0.5%;5-FU(200μg/mL) 4.0%±0.3%,4.8%±0.4%,7.7%±0.7%;DDP(150μg/mL) 8.5%±0.9%,18.6%±1.6%(P<0.05),67.0%±6.2%(P<0.01);or TAXOL(50μg/mL) 32.0%±5.2%(P<0.01),76.6%±8.5%,94.0% ±8.2%,respectively.(3) Western Blot assay showed that the expression of apoptosis associated protein.PARP,X-linked inhibitor of apoptasis(XIAP),Caspase-9 and Bcl-xL were changed.Conclusion:The sensitivity of chemotherapy could be assessed by MTT assay,Annexin V/PI assay and Western Blot.The best examine time of the three chemotherapuc agents was 5-FU(200μg/mL):>12h,DDP(150μg/mL):8-12h,or TAXOL(50μg/mL):<4h.

Cytarabine and paclitaxel exhibit different cell-cycle specificities in different cell growing status

Objective:To investigate the cell-cycle specificities of cytarabine and paclitaxel in different growing status of target cell.Methods:Using flow cytometry,we tested the cell-cycle specificities of cytarabine and paclitaxel on acute lymphocyte leukemia cell line Molt-4 in different growing status and on clinical acute lymphocyte leukemia specimens in vitro as well as in leu-kemia patients in vivo.Results:Cytarabine induced S phase specific cell-cycle blockage and apoptosis in exponentially growing Molt-4,but showed G0/G1 phase specificity in high-density cultured Molt-4 and in clinical specimens.Paclitaxel induced G2/M phase specific cell-cycle blockage and apoptosis in exponential Molt-4,but showed G0/G1 phase specificity in high-density cultured Molt-4 and S phase specificity in clinical specimens.In the first day of clinical chemotherapy,cytarabine induced G0/G1 with a little S phase apoptosis in leukemia cells of acute lymphocyte leukemia patient in vivo.Cytarabine plus paclitaxel together had almost the same effect in the second day.Conclusion:The cell-cycle effects of cytarabine and paclitaxel were different in different target cell growing status.It should be noted that the in vivo effect of these agents may be different from people usually anticipated during clinical chemotherapy.So the combined chemotherapeutic regimens may need to be redesigned.

Epidermal growth factor enhances chemosensitivityof colon cancer by inducing cancer stem cells toenter the cell cycle

Objective The aim of the study was to investigate whether colon cancer stem cells induced by epidermal growth factor(EGF) to enter the cell cycle enhanced the chemosensitivity of colon cancer.Methods In vitro,EGF was used to stimulate the entry of human colon cancer HCT116 cells into the cell cycle.Before and after treatment with EGF,CD133+ HCT116 cells were collected and flow cytometry was conducted to determine the apoptosis rate based on the 5-Fu and Ki-67 expression rates.The cell cycle distribution of the two groups was also determined.In vivo,a subcutaneous xenograft model of HCT116 human colon cancer cell lines in nude mice was established.The nude mice were divided into two groups and treated with EGF and 5-Fu,respectively.Differences in the growth of implanted tumors revealed the efficiency of cycle-induction combined chemotherapy.Results(1) After EGF stimulation,the S-G2/M proportion of CD133+ HCT116 cells and Ki67 expression were increased,indicating that more cancer stem cells entered the cell cycle and promoted proliferation;(2) After EGF stimulation,CD133+ HCT116 cells showed a higher apoptosis rate induced by 5-Fu.(3) Animal experiments showed that the group subjected to combined treatment with EGF and 5-Fu had smaller tumor sizes compared to the group treated with 5-Fu alone.Conclusion EGF enhanced tumor sensitivity to chemotherapeutic drugs,likely by promoting tumor stem cells to enter the cell cycle.

The role of CDK1 siRNA interference in cell cycle and cell apoptosis

In the present report,cyclin-dependent kinase1(CDK1)siRNA was transfected into cells to silence the CDK1 gene expression and study its role in the cell cycle and cell apoptosis.The siRNA targeting CDK1 gene was chemically synthesized and transfected into Hela cells by lipofectamine 2000.The expression levels of CDK1 gene and protein were examined by real-time quantitative polymerase chain reaction(PCR)and Western blot,respectively.The cell cycle was analyzed by using DNA content analysis byflow cytometry.Cell apoptosis was detected by the Annexin V/PI method.The morphological changes of transfected cells were examined under the microscopy by Wright-Giemsa stain.CDK1 gene was successfully silenced by its siRNA,and the CDK1 protein expression level was decreased significantly,especially from 48th h to 60th h after transfection.The DNA content analysis showed that transfection of CDK1 siRNA led to cells accumulating in G2/M phase.There was no significant difference in the apoptotic rate between transfected cells and the control cells after transfection of CDK1 siRNA for 48 or 60 h.More double nucleus or multinucleus cells could be seen under the microscopy among the transfected cells.The decreased CDK1 expression by siRNA silencing gave rise to cell cycle arrest in G2/M phase but did not induce apoptosis.