Cytopathology and Histopathology

Biography

Biography: Guoxiong Xu

Abstract

Breast cancer is the most common malignant tumor and the second leading cause of cancer death in women worldwide. Among all breast cancer cases, invasive ductal carcinoma (IDC) is the most common type of breast cancer that accounts for more than 70% of total diagnosed cases. Pyridoxine 5'-phosphate oxidase (PNPO) is a converting enzyme for pyridoxal 5'-phosphate (PLP), an active form of vitamin B6, which serves as a co-factor for more than 140 enzymes that participate many metabolic reactions. However, the biological function of PNPO in human breast IDC remains unclear. Furthermore, a regulatory mechanism of PNPO is not fully understood. Recently, we evaluate the biological function and regulatory mechanism of PNPO in human IDC. We found that PNPO was associated with IDC development and was correlated with the overall survival of patients. Loss-of-function assays showed that PNPO affected breast cancer cell proliferation, migration, invasion, colony formation, cell cycle, and apoptosis. Interestingly, we found a microRNA response element in PNPO and lncRNA MALAT1 transcripts for miR-216b-5p. Dual-luciferase reporter assays confirmed the binding of miR-216b-5p to PNPO and MALAT1. Targeting MALAT1 resulted in the alteration of the expression level of miR-216b-5p and PNPO mRNA. The change of miR-216b-5p level affected PNPO expression, indicating that PNPO was regulated by MALAT1 via miR-216b-5p. These results reveal a regulatory mechanism of competing endogenous RNAs in breast cancer.