BAP31 promotes breast cancer progression by interaction with SERCA2

Background: B-Cell receptor-associated protein 31 (BAP31) is a resident chaperone protein in the endoplasmic reticulum. It was observed herein that a higher expression of BAP31 mRNA was associated with a worse prognosis in breast cancer patients. Methods: Breast cancer cells and normal breast tissue cells were used to confirm how BAP31 influences the progress of breast cancer both in vivo and vitro. Western blots and qRT-PCR assays supported the changes. Results: Depletion of BAP31 in breast cancer cells increased apoptosis and decreased the capacities of proliferation, colony formation and invasion. BAP31 was observed to be associated with SERCA2, a sarco/endoplasmic reticulum Ca2+-ATPase. Depletion of BAP31 decreased endoplasmic reticulum Ca 2+ storage with resultant ER stress and breast cancer cell death; which required BAP31 association with SERCA2 . Conclusion: Hence, these findings have demonstrated that BAP31 enhanced the viability, oncogenicity and motility of breast cancer cells by modulation of endoplasmic reticulum Ca2+ homeostasis. Thus, BAP31 promotes progression of breast cancer.