PGRMC1Take Part In The Regulation Of Chemotherapy Sensitivity In Breast Cancer Cell

Breast cancer is one of the most common malignant tumors that pose female health risk. According to the epidemic investigation, its incidence ratio has remarkable rise in recent years. The onset of stroke has a trend of attacking young adults, especially under the aged25to35. In recent ten years, the average increasing ratio rose almost10.7%. The second peak for the desease is between55to65years old. Breast cancer has become the first or second female malignant tumor in some large or middle cities which is one of the main reasons of woman death. Early diagnosis and treatment is of significance for prolong the survival and improving life quality. It is the hot problem to find the indexes of metastasis, drug-resistance and so on biological behaviour with the molecular biologic methods. It had been shown that tumor developement is the result of multi-genes involving and influence of one another on many stages. Genetic mutations lead to cell malignant proliferation without any limitation, which is the character of tumor. Presently there are plenty of research of breast cancer genes and their influence factors which has become the focus of recent breast cancer research, which attracted more and more attention. Many studies confirmed that classical estrogen receptor ER-α was positive in50-80%breast cancer samples. It is a good phenomenon of prognosis including ratio of cell proliferation, tumor differentiation, histologic evidence. Moreover, it is the key factor to decide whether to accept endocrine therapy. But it also indicated that high risk of metasitesis, which is positive correlated with metasitasis on bone, cartilage and reproductive system. For ER-α negative patients, the brain and liver metasitasis occurred more common. Neubauer coolected tissue sections from16cryopreserved breast cancer tumors(eight ER positive and eight ER negative) and differentially analyzed by multiplex imaging of two-dimensional PAGE gels using54cm isoelectric focusing. Differentially detected spots of Progesterone Receptor Membrane Component1(PGRMC1) were shown to differ in phosphorylation status by differential two dimensional polyacrylamide gel electrophoresis of phosphatase-treated tumor proteins. Two of three spots of PGRMC1were more abundant in estrogen receptor negative tumors. PGRMC1promotes cell survival and damage resistance, involved in drug metabolism, cholesterol synthesis and hormone synthesis and turnover. PGRMC1is an attractive target for therapeutic intervention in cancer and related malignancies. In our paper, the expression of PGRMC1in breast cancer was verified by immunohistochemical method analysis of paraffin sections. PGRMC1-positive expression and breast cancer clinical pathology count including stage, grade, drug-sensitivity, follow-up materials and so on. Data using Fisher’s exact test,χ2test, Log-rank test and Kaplan-Meier method was judged the mutual relations of PGRMC1expression with clinical parameters and survival rate of patients. P<0.05was considered statistically significant. The PGRMC1expression was positive in37(61.67%) of60breast cancer. PGRMC1positive expression was signifcantly corresponding to lymph node metastasis (P=0.015), TNM stage (P=0.018) and overall survival rate (Log-rank=15.638; P=0.0001), but not to age (P=0.375), tumor size (P=0.288) and histological grade (P=0.526). PGRMC1was an independent prognostic factor by multivariate survival analysis(P=0.002).Together with its clinical role in inducing tumor chemo-resistance, we deeper study how did the PGRMC1take part in the drug sensitivity regulation in vitro. According to the design rule of siRNA, we Design and chemical synthesis two siRNAs targeting PGRMC1, and transfect into high invasive breast cancer cell line MDA-MB-231and low invasive cell line MCF-7by lipofectin2000. Detected the mRNA and protein of PGRMC1by RT-PCR and Western blot method. The siRNA-GFP is positive control, and the untreated group is blank control. The drug sensitivity of DTX was detected by CCK8method before and after transfection siRNA-PGRMC1. Treated breast cancer cell lines with half of IC50DTX, and detected cell cycle, apoptotic ratio, ROS level by FCM after stained by PI, annexin V and DCFH-DA respectively. After stained by JC-1, detected the membrane potential of mitochondrion by immunofluorescence method. All data were pointed as average values and standard deviations and analyzed by anova and t test. The numerical simulation manifests that siRNAl and2can inhibited more than70%level of the expression of PGRMC1both on mRNA and protein significantly in both high and low invasive breast cell lines. The viability of cancer cells were decreased and drug sensitivity increased with PGRMC1inhibiting. After inhibiton of PGRMC1, the cell was arrested on G2stage. Comparing with the control group, the apoptosis ratio increased with ROS level. Conclusion:PGRMC1play important role in regulating the viability and drug resistance of breast cancer.Based on our preliminary research, we gain the conclusion that chemodrug induced mitochondrial apoptotic pathway activated would significantly strengthened, after silencing the expression of PGRMC1. We also detected the miRs expression in breast cancer cell with above treatment by microarray. The result suggested that miR-128is the key factor in this function. We predicted that the mitochondrial apoptotic protein Bax is one of its targets. It was verified by Luciferase Report Assay. We detected miR-128and bax in breast cancer cell line MCF-7and MDA-MB-231, then transfected miR-128precursor(mimic) or ASO(inhibitor) into them. With the change of miR-128and bax level, the chemosensitivity of MCF-7and MDA-MB-231cell were regulated respectively. But it is unknown why miR-128was reduced after inhibiton of PGRMC1gene.The purpose of our study was to evaluating the significance of the expression of PGRMC-1in breast carcinom. How does it participate the carcinogenesis, development and chemo-resistance of breast cancer. We can draw some conlusion from our study that the level of PGRMC1was negative related with prognosis of breast cancer, if it was silednced the chemo-sensitivity will up-regulated. PGRMC1is a candidate therapeutic biomarker for breast cancer.Conclusion:PGRMC1play important role in regulating the viability and drug resistance of breast cancer.