DEGs Screening And The Effects Of PAIP1 On Biological Behaviors Of Breast Cancer

Background:Breast cancer is the most common invasive cancer in women, and genetic alteration is one of the major risk factors for the development and progression of breast cancer. Improving clinical outcomes will require a better understanding of the genetic alteration and finding which target will respond to therapies.Objectives:To identify differentially expressed genes (DEGs) in breast cancer by genechip microarray and HCS (High Contents Screening) analysis. Identify the role and mechanism of these DEGs in breast cancer development and progression in vitro. Then verify whether the DEGs were able to predict breast cancer prognosis. Finally, provide an effective molecular biomarker and therapeutic target for breast cancer.Materials and methods:1) DEGs between 20 breast cancer and paired normal breast tissues were detected by genechip microarray analysis. Then Real-time PCR and HCS analysis was performed in MDA-MB-231 breast cancer cells to validate DEGs in breast cancer.2) Target gene was knocked down by lentivirus transfection, and then the effect in cell proliferation, apoptosis and cell cycle was detected in MDA-MB-231 cells. Genechip microarray was performed to compare MDA-MB-231 cells and the cells transfected with lentivirus, to identify the DEGs and altered signaling pathway. Real-time PCR and western blot was performed to verify downstream molecular.3) PAIP1 protein expression in 119 cases of breast cancer and normal tissues were detected by immunohistochemical method, and the correlations between abnormal expression of protein and clinicopathological characteristics were also analyzed. The survival analysis was used to verify the value of evaluation of target protein in prognosis of the patient.Results:1) Genechip microarray analysis showed that 1,997 genes had significantly (p<0.05) altered expression compared with normal breast tissues, with 1,054 genes being up regulated and 943 genes down regulated. Further, real-time PCR and HCS analysis showed that PAIP1. HSDL2. WDR67 have the largest potential to be a new biomarker or therapeutic target for breast cancer.2) Knocking down of PAIP1 significantly inhibited cell proliferation, induced cell cycle arrest and cell apoptosis. Gene microarray analysis identified differentially regulated gene following PAIP1 alteration were significantly linked to cell cycle, apoptosis, proliferation, and cell metabolism. In addition, Real-time PCR and western blot analysis showed that knocking down of PAIP1 significantly down regulated MYD88, CDK6, and up regulated IL-1B protein expression.3) IHC and IF analysis showed that PAIP1 was mainly expressed in cytopalsm. IHC analysis showed that the positive rates of PAIP1 in breast cancer tissues (60.5%) was significantly higher than in normal breast tissues (17.5%), and were related with clinical stage, pathological grade; Survival analysis showed that abnormal expression of PAIP1 was closely related with breast cancer survival (p<0.05), whereas in the late clinical stage and PR (+) status, PAIP1 over expression was closely related to bad prognosis (p< 0.05).Conclusions:1) PAIP1, HSDL2 and WDR67 were important DEGs in breast cancer progression.2) PAIP1 significantly induced breast cancer cell proliferation, cancer cell mitosis and inhibited apoptosis in vitro, and the mechanism might be related to down regulation of IL-1B, and up regulation of MYD88, CDK6.3) PAIP1 can be used as a biomarker to predict poor prognosis of breast cancer, and new target gene for breast cancer therapy.