Abstract 278: Role of ATPIF1 in glioblastoma cell survival and metabolism

Abstract The ATPase inhibitory factor 1 (ATPIF1) is a 12 kDa protein that inhibits the mitochondrial F1Fo-ATP synthase in the F1domain. It reverses the mitochondrial ATP synthase complex's function, contributing to the onset of oncogenesis. The overexpression of ATPIF1 in various cancers has recently attracted greater attention; however, its biological significance in human pathology, specifically cancer, remains unknown. Based on immunohistochemistry and Western blot analysis of glioblastoma (GBM) patient specimens, we found ATPIF1 is highly expressed in GBMs. Here we showed that mitochondrial fractions of silencing ATPIF1 in U-87 and U251 cells showed decreased expression of ATPIF1, ATP5A, and ATPG1-G2-G3. Next, we showed that manipulation of ATPIF1 showed increased Reactive Oxygen Species (ROS) and Caspase3/7 activity levels compared to untreated cells. ATPIF1 knockdown further caused cell cycle arrest at the G₀/G1stage, and FITC Annexin V analysis showed increased apoptosis. Increased glucose uptake is associated with aggressive oncological behavior, and here we found elevated levels of TCA metabolites in ATPIF1 knockdown cells. ATPIF1 silenced cells had a shift in extracellular acidification rate, accompanied by a simultaneous increase in proton leak, according to the metabolic analysis performed by Seahorse bio-analyzer. Overall, these observations suggest ATPIF1 plays a key role in the progression of GBM. However, further research is needed to verify the precise mechanisms by which ATPIF1 functions in GBM. Citation Format: Maheedhara Reddy Guda, Nelli Mnatsakanyan, Daniel Morris, Swapna Asuthkar, Andrew J. Tsung, Kiran Velpula. Role of ATPIF1 in glioblastoma cell survival and metabolism [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 278.