Exploiting a subtype-specific mitochondrial vulnerability for successful treatment of colorectal peritoneal metastases

Peritoneal metastases (PM) in colorectal cancer (CRC) present a significant challenge due to limited treatment options and poor patient prognosis. While cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) offers curative potential for selected patients, its overall benefit remains limited compared to surgery alone. In this study we show that the majority of CRC-PM represent the CMS4-subtype. Despite CRS-HIPEC treatment, CMS4 patients had high rates of recurrent disease and mortality, indicating limited effectiveness of the treatment. To explore alternative treatment approaches, we queried large-scale compound screens and discovered the copper (Cu)-ionophore elesclomol (ES) as a highly effective agent against CMS4-specific disease models. ES exhibited rapid and selective cytotoxicity against CMS4 cells by targeting the oxidative phosphorylation machinery. CMS4 cells had reduced absolute mitochondrial content and lower expression of genes involved in oxidative phosphorylation, making them vulnerable to ES-induced cytotoxicity. Short exposures to ES combined with Cu (ES-Cu) resulted in near-complete growth inhibition of cancer cells, suggesting its potential for HIPEC-like intra-abdominal treatment procedures. Furthermore, ES-Cu demonstrated efficacy in preclinical models of PM, including CRC-PM and ovarian cancer organoids, and a HIPEC rat model of PM. These findings highlight ES-Cu as promising candidate for the local treatment of CRC-PM, with broader implications for other cancer types characterized by high incidence of PM.