Expression Of IQGAP2 In Breast Cancer And Its Effect On Biological Behavior Of Triple Negative Breast Cancer Cells

Background Breast cancer is a malignant tumor in the breast epithelium.It is one of the most common malignant tumors in women,with the second highest mortality rate.Because of the high heterogeneity of breast cancer,different molecular subtypes of breast cancer patients have different prognosis.According to immunohistochemistry and/or gene expression profiling,breast cancer was allocated to luminal type,HER-2 positive and triple negative.Among them,the effective targeted therapy of triple-negative breast cancer(TNBC)was lacked and and the prognosis was poor.Therefore,it is important to explore the specific mechanism of TNBC development and improve the prognosis of patients with TNBC.IQGAP2 is a member of the IQGAPs family,and its loss of expression plays a role in promoting the development of hepatocellular carcinoma,gastric cancer,ovarian cancer and prostate cancer.At present,the expression and function of IQGAP2 in breast cancer have not been reported.Aim To investigate the expression of IQGAP2 in breast cancer and the effect of silencing IQGAP2 on proliferation,migration and invasion of triple negative breast cancer cells in vitro.Methods 1.UALCAN database was used to analyze the expression of IQGAP2 in normal breast tissue and different molecular subtypes of breast cancer.2.Triple negative breast cancer cell line SUM159 was used to transfect si RNA(si IQGAP2)targeting the IQGAP2 gene,and interference efficiency was detected by q RT-PCR and western blot.3.Effect of interfering IQGAP2 expression on cell viability of triple negative breast cancer cell line SUM159 was observed by cell viability experiment.4.Effect of interfering IQGAP2 expression on cell migration and invasion ability of triple negative breast cancer cell line SUM159 was observed through cell migration and invasion experiments.Result 1)UALCAN database was used to analyze and compare the expression levels of IQGAP2 in 114 normal breast tissues and 1097 breast cancer tissues,and the results showed that the median expression level of IQGAP2 in normal breast cancer tissues was 27.772,significantly higher than the median expression level of IQGAP2 in breast cancer tissues(P< 0.01).2)According to the molecular classification of breast cancer,Luminal type 566 cases of breast cancer,HER-2 expression type of 37 cases of breast cancer,116 cases TNBC,comparison between groups IQGAP2 expression level the median value,which type Luminal breast cancer IQGAP2 expression level in the median value is 17.981,positive HER-2 breast cancer IQGAP2 expression level in the median value is 14.143,were higher than in TNBC IQGAP2 expression level the median value of 5.707(P< 0.01).3)q RT-PCR and western blot results showed that m RNA and protein expression levels of si IQGAP2 were significantly reduced in SUM159,a triple negative breast cancer cell(P<0.01).4)In SUM159 cells,the results of cell viability assay showed that the cell viability was significantly increased after si IQGAP2 transfection(P<0.01).5)In SUM159 cells,the results of cell migration and invasion assay showed that the cell migration and invasion were significantly enhanced after si IQGAP2 transfection(P<0.01).Conclusion IQGAP2 may be involved in the regulation of biological behaviors of triple-negative breast cancer,and may be a potential marker for the diagnosis and prognosis in triple-negative breast cancer patients.