Cisplatin Repressed Growth Of Breast Cancer Cells Through Autophagy Pathway

Objective Autophagy, also termed as type II programmed cell death(programmed cell death,PCD). Chemotherapy plays an important role in cancer therapy. However, the mechanism is not fully understood. In the present study, we investigated whether the cytotoxic effects of chemotherapeutics against breast cancer cells could be due to the induction of autophagy.Methods : Proliferation was determined by MTT(3-[4,5-dimethyltiazol-2-yl] 2,5-diphenyl-tetrazolium bromide).Formation of LC3 punctate was visualized by using the Ds Red-LC3 reporter. Cell cycle was tested by flow cytometry.To verify whether the growth inhibition induced by chemotherapeutics was executed through an autophagy dependent manner, we investigated the effect of 3-MA, a classic autophagy inhibitor, on the cytotoxicity of chemotherapeutics.Expressions of autophagy-related genes,The expression level of autophagy related gene(ATG) in breast cancer cell lines were determined by Real time-PCR.Results1. Epirubcin, MTX, CTX and cisplatin repressed the growth of MDA-MB-231 and MDA-MB-453 breast cell in a dose-dependent and time-dependent manner。2. By using the Ds Red-LC3 reporter, the increased formation of LC3 punctate was observed following the treatment with cisplatin, but not by other chemotherapeutics, suggesting cisplatin could induce autophagy in breast cancer cells.3. 3-MA had no effect on epirubcin, MTX and CTX, consisting with undetectable autophagy by these chemotherapeutics. 3-MA attenuated the cytotoxicity of cisplatin against breast cancer cells.4. Cisplatin induced G2/M cell cycle arrest in breast cancer cells.5. Real-time PCR revealed that cisplatin up-regulated multiple autophagy-related genes, including AMBRA1, ATG3, ATG4 C, ATG4 D, ATG5, ATG7, ATG13, ATG14, ATG16L2, Beclin1, DRAM1, GABARAP, GABARAPL1, GABARAPL2, HDAC6, IRGM, MAP1LC3 B and ULK1.Conclusion In our study, we have proved that epirubcin, MTX, CTX and cisplatin repressed growth of MDA-MB-231 and MDA-MB-453 cells through dose- and time-dependent manner. Among these chemotherapeutics, only cisplatin triggered autophagy, which could be due to up-regulation of multiple autophagy-related genes. Cisplatin arrested cell cycle in G2/M phase and fulfilled cytotoxicity through an autophagy pathway dependent manner.