Homocapsaicin II induce ferroptosis in colorectal cancer cells via cholesterol-centrosome amplification-multipolarity...

Homocapsaicin II (Hp II), a natural product abundantly found in Capsicum annuum L., is a structural analog of capsaicin. Traditionally, capsaicin is utilized for managing digestive disorders and analgesic applications. Although emerging evidence suggests anti-cancer properties of capsaicin and its analogs, the specific anti-tumor properties and mechanisms of Hp II remain completely unexplored. Our study demonstrates that Hp II suppresses colorectal cancer progression via ferroptosis induction, both in vitro and in vivo.

Anti-cancer activity of Hp II was assessed using colorectal cancer cell lines (in vitro) and subcutaneous tumor xenografts in nude mice (in vivo). Potential protein targets were identified through bioinformatic profiling, with KIF11 validated as a direct binding partner via epoxy-activated sepharose 6B-Hp II pull-down assays and microscale thermophoresis (MST). Ferroptotic mechanisms were dissected using molecular and cellular approaches, including intercellular free Fe²⁺ and lipid peroxidation quantification.

Hp II was found to target KIF11 in this study. It bound to KIF11 and stabilized it by reducing its ubiquitination. Increased levels of KIF11 promoted cholesterol production, leading to centrosome amplification (CA). Additionally, KIF11 played a role in centrosome separation, contributing to multipolarity. Ultimately, Cholesterol-induced CA and KIF11-mediated multipolarity synergy led to ferroptosis. This was supported by elevated levels of free Fe²⁺ and lipid peroxidation, a decreased GSH/GSSG ratio, and changes in the protein levels of ferroptosis markers ACSL5 and STEAP3 (upregulated) as well as FTH1 and GPX4 (downregulated).

In summary, Hp II acts as a dual-pathway inducer targeting both cholesterol-driven CA and KIF11-mediated centrosome separation to trigger ferroptosis. These findings position Hp II-KIF11 as a metabolic-mitotic ferroptosis regulator, connecting cholesterol metabolism, centrosome dynamics, and oxidative cell death.