SGLT2 inhibitor promotes mitochondrial dysfunction and ER-phagy in colorectal cancer cells
Camilla Anastasio, Isabella Donisi, Vitale Del Vecchio, Antonino Colloca, Luigi Mele, Celestino Sardu, Raffaele Marfella, Maria Luisa Balestrieri, Nunzia D’Onofrio
Abstract
BACKGROUND: Sodium-glucose transporter 2 (SGLT2) inhibitors (iSGLT2) are approved medications for type 2 diabetes. Recent studies indicate that iSGLT2 inhibit the growth of some cancer cells. However, the mechanism(s) remains to be fully elucidated. METHODS: The SGLT2 levels were determined in normal colon CCD 841 CoN and, HCT 116, HT-29, SW480 and LoVo colorectal cancer (CRC) cell lines by quantitative real-time PCR and western blot. The effect of iSGLT2 canagliflozin on cell proliferation was examined using CCK-8, as its role on CRC cells metabolism and tumorigenesis has been evaluated by XF HS Seahorse Bioanalyzer and flow cytometric analyses. Transient gene silencing experiments and analysis of protein-protein interaction network were conducted to evaluate the SGLT2 molecular targets in CRC cells. RESULTS: Data showed that the treatment with iSGLT2 (50 µM) for 72 h induced cell cycle arrest (p < 0.001), impaired glucose and energetic metabolism (p < 0.001), promoted apoptotic cell death and ER stress flowing into autophagy (p < 0.001) in HCT 116 and HT-29 cells. These cellular events were accompanied by sirtuin 3 (SIRT3) upregulation (p < 0.01), as also supported by SIRT3 transient silencing experiments resulting in the attenuation of the effects of iSGLT2 on the cellular metabolic/energetic alterations and the induction of programmed cell death. The identification and validation of dipeptidyl peptidase 4 (DPP4) as potential common target of SGLT2 and SIRT3 were also assessed. CONCLUSIONS: These results deepened knowledge on the iSGLT2 contribution in limiting CRC tumorigenesis unveiling the SGLT2/SIRT3 axis in the cytotoxic mechanisms.