AP2α negatively regulates PDHA1 in cervical cancer cells to promote aggressive features and aerobic glycolysis in vitro and in vivo

Abstract

Objective: As a gate-keeper enzyme link, pyruvate dehydrogenase E1 subunit alpha (PDHA1) functions as a key regulator during glycolysis and the mitochondrial citric acid cycle, which has been reported in several tumors. Nevertheless, the effects of PDHA1 on biological behaviors and metabolism remain unclear in cervical cancer (CC) cells. The study aims to explore the PDHA1 effects on glucose metabolism in CC cells and its possible mechanism.

Methods: We first determined the expression levels of PDHA1 and activating protein 2 alpha (AP2α) as a PDHA1 potential transcription factor. The effects of PDHA1 in vivo were evaluated through a subcutaneous xenograft mouse model. Cell Counting Kit-8 assay, 5-ethynyl-2'-deoxyuridine (EdU) labeling assay, Transwell invasion assay, wound healing assay, Terminal deoxynucleotidyl transferase dUTP nick end labeling assay and flow cytometry were performed in CC cells. Oxygen consumption rate (OCR) levels were determined to reflect aerobic glycolysis level in gastric cancer cells. Reactive oxygen species (ROS) level was measured with 2', 7'-dichlorofluorescein diacetate kit. The relationship between PDHA1 and AP2α was examined by conducting chromatin immunoprecipitation assay and electrophoretic mobility shift assay.

Results: In CC tissues and cell lines, PDHA1 was downregulated, while AP2α was upregulated. Overexpression of PDHA1 remarkedly inhibited the proliferation, invasion and migration of CC cells, and tumor growth in vivo, as well as promoted OCR, apoptosis and ROS production. Moreover, AP2α directly bound to PDHA1 within suppressor of cytokine signaling 3 promoter region to negatively regulate PDHA1 expression level. What is more, PDHA1 knockdown could effectively reversed the AP2α silencing-mediated suppressive effects on cell proliferation, invasion, migration, and the promotive effects of AP2α knockdown on OCR, apoptosis and ROS production.

Conclusions: Our findings demonstrate that AP2α negatively regulated PDHA1 via binding to PDHA1 gene promoter to promote malignant CC cell behaviors, which may provide a potential approach for CC therapeutics.

Keywords: Cytokines; Glycolysis; Neoplasms; Pyruvates.