SKF-96365 activates cytoprotective autophagy to delay apoptosis in colorectal cancer cells through inhibition of the calcium/CaMKIIγ/AKT-mediated pathway

• SKF-96365 activates autophagy to delay apoptosis in colorectal cancer cells.
• CaMKIIγ couples SOCE to the downstream AKT/mTOR signaling cascade.
• Ca2+/CaMKIIγ/AKT regulates apoptosis and autophagy simultaneously in cancer cells.
• SKF-96365 plus autophagy inhibitor represents a promising strategy for CRC patients.

Store-operated Ca2+ entry (SOCE) inhibitors are emerging as an attractive new generation of anti-cancer drugs. Here, we report that SKF-96365, an SOCE inhibitor, exhibits potent anti-neoplastic activity by inducing cell-cycle arrest and apoptosis in colorectal cancer cells. In the meantime, SKF-96365 also induces cytoprotective autophagy to delay apoptosis by preventing the release of cytochrome c (cyt c) from the mitochondria into the cytoplasm. Mechanistically, SKF-96365 treatment inhibited the calcium/calmodulin-dependent protein kinase IIγ (CaMKIIγ)/AKT signaling cascade in vitro and in vivo. Overexpression of CaMKIIγ or AKT abolished the effects of SKF-96365 on cancer cells, suggesting a critical role of the CaMKIIγ/AKT signaling pathway in SFK-96365-induced biological effects. Moreover, Hydroxychloroquine (HCQ), an FDA-approved drug used to inhibit autophagy, could significantly augment the anti-cancer effect of SFK-96365 in a mouse xenograft model. To our best knowledge, this is the first report to demonstrate that calcium/CaMKIIγ/AKT signaling can regulate apoptosis and autophagy simultaneously in cancer cells, and the combination of the SOCE inhibitor SKF-96365 with autophagy inhibitors represents a promising strategy for treating patients with colorectal cancer.