Radioresistance Impact Of MCF-7 Cells/cancer Stem Cell Subpopulation To CHK1/2 Signaling Pathway Inhibition

Partâ… :Radiosensitivity impact of MCF-7 cells to CHK1/2 signaling pathway inhibitionObjective: To determine the radiosensitivity of MCF-7 cells to DNA damage checkpoint CHK1/2 signaling pathway inhibitior.Methods: Using western blot detection of pCHK1/2 expression change of MCF-7 cells to DBH(CHK1/2 inhibitior)-radiotherapy;MTT application to proliferation diversity of MCF-7 cells after DBH-radiotherapy.Results: DBH to the breast cancer cell line MCF-7 has no significant toxicity.The radiotherapy can increase pCHK1/2, with which the radiation dose is positively correlated (P <0.01).pCHK1 and pCHK2 can be regulated down by DBH-radiotherapy (P <0.01),with which the radiation dose is positively correlated (P <0.05). The down-rate of pCHK1/2 has no significant correlation with radiotherapy before and after DBH, which prove that DBH as a efficacy inhibitior is relatively stable;Low-dose radiotherapy combined with DBH achieve even more than high-dose alone in MCF-7 apoptosis rate (P <0.01), which prove that the inhibition of cell cycle checkpoints CHK1/2 molecules signaling pathway can depress cell DNA damage repair significantly.Conclusion: The inhibition of CHK1/2 molecule signaling pathway can promote radiosensitivity of MCF-7 cells. Partâ…¡:Radioresistance impact of MCF-7 cells to CHK1/2 signaling pathway inhibitionObjective: To determine the radioresistance of MCF-7 breast cancer stem cells to DNA damage checkpoint CHK1/2 signaling pathway inhibitior.Methods:Flow cytometry to detect the ratio of CD44+CD24- (cancer stem cells) population of MCF-7 cells after different radiotherapy doses;Immunofluorescence to determin influence of DBH - radiotherapy with regard to the ratio of CD44+CD24- population in MCF-7 cells.Results:The radiotherapy can increase the proportion of CD44+CD24- (cancer stem cells) population of MCF-7 cells which is positively correlated with the radiation dose and the culture time (P <0.05). DBH- radiotherapy which display the stable relatively effect can be significantly reduced the proportion of CD44+CD24- population of MCF-7 cells . The down-rate is positivly correlated with the culture time (P <0.05) and had more obvious differences after three days culture (P <0.01).Conclusion: The inhibition of CHK1/2 molecule signaling pathway can reverse radioresistance of MCF-7 breast cancer stem cell population .