Study Of The Effect And Mechanism Of Crude Extracts Of Prunella Vulgaris On The Breast Cancer Cells Proliferation And Drug Resistance

ObjectiveThe primary hurdle for effective cancer chemotherapy has been the intrinsic or acquired resistance of cancer cells to a variety of anticancer agents with distinct chemical structures or mechanisms of action, a phenomenon known as drug resistance. It is one of the major causes of failures of chemotherapy of human malignancies . With many effective components obtained from Chinese traditional medicines, more and more researchers realized the unique characteristics of Chinese traditional medicimes, because they can not only modulate and enhance the body's immunity functions, but also play the distinct roles of increase effect and decrease toxicity. Prunella vulgaris is a kind of anticancer traditional medicines in common use. The main components of Prunella vulgaris are triterpene and its glycosides, sterin and its glycosides, flavonoids, 2 - benzopyrone et al, and these components possess extensive biological activities. In this study, human breast cancer cell adriamycin sensitive cells MCF - 7/S and adriamycin resistance cells MCF - 7/R were selected to study the effect and mechanism of PVC on the proliferation of MCF - 7/S cells and MCF - 7/R cells and the drug resistance of MCF -7/R cells to adriamycin.MethodsThe traditional medicine Prunella vulgaris was extracted by Aqueous Extract and Alcohol Depesit. Inhibition and IC₅₀ values of PVC on MCF - 7/S cells and MCF - 7/R cells, and the reverse effects on MCF - 7/R cells were assayed byMTT assays. The expressions of apoptosis related protein p53 and breast cancer resistant protein ( BCRP) were measured by Western Blot.ResultWith the toxic dose, PVC can inhibite the proliferation and induce the apoptosis of MCF - 7/S cells and MCF - 7/R cells. The inhibition of PVC was dose/time - dependent. IC50values of MCF - 7/S cells and MCF - 7/R cells to PVC were 81.12 ±5.12 and 77.73 ±5.2, respectively. Treated with the dose of 50, lOOmg/ml PVC for 48h, the expressions of p53 in MCF -7/S cells and MCF -7/R cells were decreased.With the non -toxic dose, PVC can reverse the drug resistance of MCF -7/R cells to adriamycin. Under the dose of 11. 87 ±0. 53mg/ml, PVC had no effects on the proliferations of MCF - 7/R cells and the survival rates of MCF -7/R cells was above 95%. The non - toxic dose of PVC to MCF -7/R cells was 12.5mg/ml. Treated with 12. 5mg/ml PVC, the IC50( jxg/ml) of MCF -7/R cells to adriamycin was decreased from 52. 81 to 28. 78, the reverse factor ( RF) was 1. 83, and the expression of BCRP was decreased and the expression of p53 was increased.ConclusionWith the toxic dose, PVC can inhibite the proliferation of MCF - 7/S cells and MCF - 7/R cells in the manner of dose/time - dependent and induce the apoptosis of MCF - 7/S cells and MCF - 7/R cells;With the non - toxic dose, PVC can reverse the drug resistance of MCF - 7/R cells to adriamycin which was related with decreasing the over - expression of BCRP and increasing the expression of p53.