Modified Banxia Xiexin Decoction promotes mitochondrial fission in colon cancer cells by inhibiting the CHD6-TMEM65 axis.

[ETHNOPHARMACOLOGICAL RELEVANCE] The Chinese herbal medicine Banxia Xiexin Decoction (BXD) and its modified version (mBXD) are traditional polyherbal formulations used to treat gastrointestinal diseases. Increasing evidence indicates that mBXD exhibits distinct anti-cancer properties; however, the mechanisms through which it modulates mitochondrial dynamics to inhibit colon cancer remain unclear.

[AIMS OF THE STUDY] To investigate the mechanisms by which mBXD suppresses colon cancer by regulating mitochondrial fusion-fission dynamics.

[MATERIALS AND METHODS] The chemical composition of mBXD was analyzed using UPLC-MS/MS. A subcutaneous CT26 colon cancer model was established and treated with mBXD. mBXD drug-containing serum was prepared and applied to HCT116 and CT26 cells. Tumor volume, small-animal live imaging, and histopathological features were evaluated. The effects of mBXD on mitochondria were examined through mitochondrial ultrastructure analysis, JC-1 detection, and assessment of ATP concentration and ROS levels. WB and qPCR were performed to determine the expression of molecules associated with the CHD6-TMEM65 axis and mitochondrial dynamics.

[RESULTS] The main components of mBXD were identified as flavonoids and alkaloids. These compounds significantly inhibited tumor growth, with higher concentrations of mBXD drug-containing serum reducing the survival, invasion, and migration of HCT116 and CT26 cells. Moreover, mBXD markedly promoted mitochondrial fission in cancer cells, reduced ATP levels, and induced ROS accumulation. It significantly upregulated DRP1 expression while inhibiting CHD6 and TMEM65, with no notable effect on OPA1.

[CONCLUSIONS] The chemical constituents of mBXD mainly comprise flavonoids and alkaloids. These components markedly inhibit the growth of subcutaneous tumors in CT26 colon cancer-bearing mice and suppress the viability, invasiveness, and migratory capacity of HCT116 and CT26 cells. The underlying mechanism may involve the promotion of mitochondrial fission in cancer cells through inhibition of the CHD6-TMEM65 axis, ultimately leading to apoptosis. Nonetheless, the present study has certain limitations. The precise mechanisms by which mBXD induces mitochondrial fission and inhibits the CHD6-TMEM65 axis warrant further investigation in future research.