Abstract 4421: IGF2 regulates mitochondrial cell energy phenotype and biogenesis in TNBC cells

Triple-negative breast cancer (TNBC) is very aggressive, resistant to chemotherapy and more likely to relapse, causing the worst prognosis. African American (AA) women suffer higher incidence and mortality of TNBC due to the expression of high levels of Insulin Growth Factor 2 (IGF2) which promotes tumor progression, metastasis, and chemoresistance. Also, it has been established that functional mitochondria and mitochondrial DNA (mtDNA) are essential for cancer cell growth. Mutations and/or reductions in mtDNA copy number that alter the Oxidative Phosphorylation (OXPHOS) physiology are common features of TNBC. We have demonstrated that mtDNA content is lower in CRL-2335 AA TNBC cell line when compared to the CRL-2335 IGF2 knockout cell line. Thus, we propose that IGF2 regulates the mtDNA content. This study was designed to demonstrate if IGF2 regulates mitochondrial genes to determine the cell energy phenotype. An XFp analyzer was used to study the mitochondrial function in terms of OCR (Oxygen Consumption Rate/Mitochondrial Respiration) and ECAR (Extracellular Acidification Rate/ Glycolysis) in the wild type and IGF2 stable knockout of CRL-2335 AA TNBC cells. Real Time PCR was performed to study the gene expression pattern of IGF2, PGC1α and PGC1β. PGC1α and PGC1β are critical genes in the regulation of the mitochondrial biogenesis, thus, they are important in the cellular metabolic phenotype. Utilizing the Seahorse metabolic system we assessed cell energy phenotype and alterations in terms of mitochondrial respiration rate (OCR) % and Glycolysis (ECAR) %. Our preliminary results showed that the overall OCR and ECAR of the stressed CRL-2335 AA TNBC cells was altered according to the levels of IGF-II expressed. Furthermore, the results demonstrated that there was a metabolic shift in the CRL-2335 AA TNBC cells towards the glycolytic pathway when IGF2 was knockout in comparison to the wild type CRL-2335 cells. Also, IGF2 knockout cells showed higher gene expression rate of PGC1β as compared to the wild type. The above data confirms that IGF2 plays a critical role in determining the cell energy phenotype. Citation Format: Maria L. Pagan, Vinodh Kumar Radhakrishnan, Daisy De Leon. IGF2 regulates mitochondrial cell energy phenotype and biogenesis in TNBC cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4421. doi:10.1158/1538-7445.AM2017-4421