Sodium butyrate-induced autophagy in colorectal cancer unveils the Ca²⁺/CaMKKβ signaling pathway as a potential therapeutic target

Abstract

Abstract Colorectal cancer’s autophagy process is facilitated by sodium butyrate (NaB), but the mechanism remains unclear. This study aimed to elucidate the effects and underlying mechanisms of NaB-induced autophagy in colorectal cancer cells. In colorectal cancer cells, NaB has been shown to upregulate the expression of autophagy-related proteins, including microtubule-associated protein 1 A/1B-light chain 3 (LC3), thereby promoting autophagosome formation. Furthermore, NaB induces the activation of Ca 2+ /calmodulin-dependent kinase kinase β (CaMKKβ), AMP-activated protein kinase α (AMPKα), and acetyl-CoA carboxylase (ACC). Moreover, inhibiting CaMKKβ with STO-609 or downregulating CaMKKβ expression using RNA interference significantly attenuated the autophagic effect induced by NaB in colorectal cancer cells, leading to reduced expression of phosphorylated CaMKKβ, AMPKα, and ACC proteins. Furthermore, sequestering cytoplasmic calcium has been found to diminish NaB-induced autophagy and partially inhibit the activation of CaMKKβ, AMPKα, and ACC proteins. The findings indicate that NaB stimulates autophagy in colorectal cancer cells by modulating Ca 2+ /CaMKKβ signaling pathways.