Insulin-like growth factor 1 signaling is essential for mitochondrial biogenesis and mitophagy in cancer cells

• Published in: The Journal of biological chemistry 2017-10, Vol.292 (41), p.16983-16998
• Main Authors: Lyons, Amy, Coleman, Michael, Riis, Sarah, Favre, Cedric, O'Flanagan, Ciara H., Zhdanov, Alexander V., Papkovsky, Dmitri B., Hursting, Stephen D., O'Connor, Rosemary
• Format: Article
• Language: English
• Subjects: cancer biology; cancer therapy; Carrier Proteins - genetics; Carrier Proteins - metabolism; cell metabolism; cell signaling; cell surface receptor; Cell Survival - genetics; drug resistance; Humans; insulin-like growth factor (IGF); Insulin-Like Growth Factor I - genetics; Insulin-Like Growth Factor I - metabolism; MCF-7 Cells; Membrane Proteins - genetics; Membrane Proteins - metabolism; mitochondria; Mitochondria - genetics; Mitochondria - metabolism; Mitochondrial Dynamics; Mitophagy; Molecular Bases of Disease; Neoplasm Proteins - genetics; Neoplasm Proteins - metabolism; Neoplasms - genetics; Neoplasms - metabolism; Neoplasms - pathology; NF-E2-Related Factor 2 - genetics; NF-E2-Related Factor 2 - metabolism; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha - genetics; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha - metabolism; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins - metabolism; Receptor, IGF Type 1; Receptors, Somatomedin - genetics; Receptors, Somatomedin - metabolism; RNA-Binding Proteins; Signal Transduction; Tumor Suppressor Proteins - genetics; Tumor Suppressor Proteins - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M117.792838

Mitochondrial activity and metabolic reprogramming influence the phenotype of cancer cells and resistance to targeted therapy. We previously established that an insulin-like growth factor 1 (IGF-1)-inducible mitochondrial UTP carrier (PNC1/SLC25A33) promotes cell growth. This prompted us to investigate whether IGF signaling is essential for mitochondrial maintenance in cancer cells and whether this contributes to therapy resistance. Here we show that IGF-1 stimulates mitochondrial biogenesis in a range of cell lines. In MCF-7 and ZR75.1 breast cancer cells, IGF-1 induces peroxisome proliferator–activated receptor γ coactivator 1β (PGC-1β) and PGC-1α–related coactivator (PRC). Suppression of PGC-1β and PRC with siRNA reverses the effects of IGF-1 and disrupts mitochondrial morphology and membrane potential. IGF-1 also induced expression of the redox regulator nuclear factor-erythroid-derived 2-like 2 (NFE2L2 alias NRF-2). Of note, MCF-7 cells with acquired resistance to an IGF-1 receptor (IGF-1R) tyrosine kinase inhibitor exhibited reduced expression of PGC-1β, PRC, and mitochondrial biogenesis. Interestingly, these cells exhibited mitochondrial dysfunction, indicated by reactive oxygen species expression, reduced expression of the mitophagy mediators BNIP3 and BNIP3L, and impaired mitophagy. In agreement with this, IGF-1 robustly induced BNIP3 accumulation in mitochondria. Other active receptor tyrosine kinases could not compensate for reduced IGF-1R activity in mitochondrial protection, and MCF-7 cells with suppressed IGF-1R activity became highly dependent on glycolysis for survival. We conclude that IGF-1 signaling is essential for sustaining cancer cell viability by stimulating both mitochondrial biogenesis and turnover through BNIP3 induction. This core mitochondrial protective signal is likely to strongly influence responses to therapy and the phenotypic evolution of cancer.