Influence Of Different Timing Intervals Between NP Chemotherapy And Radiotherapy Upon MCF-7 Breast Cancer Cell

Objictive:To evaluate the effect of the treatment by vinovelbine(NVB) and cisplatin(DDP) with radiation at different timing intervals on the radiosensitivity and apoptosis of human breast cancer cell MCF-7. Methods:Six groups(at the interval of 0h, 4h, 12h, 36h, 48h, 72h between chemotherapy and radiotherapy)were studied by cologenic formation assay. Cologenic formation assay was used for cell survival curves in vitro. The difference of radio sensitivities was calculated by the comparition and statistic of SF data. In addition, the effect of different timing intervals between chemotherapy and radiotherapy on cell cycle distribution and apoptosis induction in MCF-7 cells was also studied. Quantitation of the apopotic cells was performed by Flow cytometry measurements. For the qualitative detection, fluorescence microscopy analysis was used.Results: 1)NP chemotherapy can reduce adriamycin resistance MCF-7 cell SF data and indicate AUC dependence; 2) The six groups have different SF data, it is the lowest one at the intervals 12h group, the middest one at Oh groups, and the higgest one at48, 72h groups when the radiation dose is 8 Gy.3) In some degree, the different SF data of the six groups can been explained by the different percentage accumulation of G2/M phase at different timing caused by the NP chemotherapy. 4)Apoptosis index after chemotherapy increase with time extending, but the changes of apoptosis index seem not correlate with the SF differences.Conclusion:The different timing intervals between NP chemotherapy and radiotherapy affect the radiosensitivity of MCF-7 cells, but those changes according to the interactive of cycle distribution and apoptosis et al.