Smilax glabra Flavonoids Inhibit AMPK Activation and Induce Ferroptosis in Obesity-Associated Colorectal Cancer.

Smilax glabra flavonoids (SGF), the active components of Smilax glabra Roxb., have been demonstrated to exhibit antioxidant activity and metabolic benefits in obesity, leading us to further explore their antitumor effects in obesity-related colorectal cancer (CRC). This study investigated the antiproliferative effects of SGF on obesity-related CRC by using a murine colon adenocarcinoma MC38 cell line. The underlying mechanisms were further explored via RNA-Seq and bioinformatics analysis in combination with experimental validation. SGF was proven to possess cytotoxic effects against MC38 cells, indicated by the inhibition of proliferation and migration, especially in an adipocyte-rich environment. In line with this, SGF exhibited much stronger antiproliferative effects on MC38-transplanted tumors in obese mice. Transcriptomics analysis showed that the cytotoxic effects of SGF might be related to the AMPK pathway and ferroptosis. On this basis, SGF was confirmed to induce ferroptosis and dictate ferroptosis sensitivity in a high-fat context mimicked by a two-step conditioned medium (CM) transfer experiment or a Transwell coculture system. The results of Western blotting validated that SGF suppressed the phosphorylation of AMPK, accompanied by alterations in the biomarkers of ferroptosis. These results demonstrate that SGF exerts in vitro and in vivo antiproliferative effects in obesity-associated CRC through inhibiting AMPK activation, thereby driving ferroptosis.