Driver gene KRAS aggravates cancer-associated stroke outcomes

The incidence of cancer-associated stroke has increased with the prolonged survival times of cancer patients. Recent genetic studies have led to progress in cancer therapeutics, but relationships between oncogenic mutations and stroke remain elusive. Here, we focused on the driver gene KRAS, which is the predominant RAS isoform mutated in multiple cancer types, in cancer associated stroke study. KRAS^G13D/- and parental human colorectal carcinoma HCT116 cells were inoculated into mice that were then subjected to a photochemically-induced thrombosis model to establish ischemic stroke. We found that cancer inoculation exacerbated neurological deficits after stroke. Moreover, mice inoculated with KRAS^G13D/- cells showed worse neurological deficits after stroke compared with mice inoculated with parental cells. Stroke promoted tumor growth, and the KRAS^G13D/- allele enhanced this growth. Brain RNA sequencing analysis and serum ELISA showed that chemokines and cytokines mediating pro-inflammatory responses were upregulated in mice inoculated with KRAS^G13D/- cells compared with those inoculated with parental cells. STAT3 phosphorylation was promoted following ischemic stroke in the KRAS^G13D/- group compared with in the parental group, and STAT3 inhibition significantly ameliorated stroke outcomes by mitigating microglia/macrophage polarization. Finally, we compared the prognosis and mortality of colorectal cancer patients with or without stroke onset between 1 January 2007 and 31 December 2020 using a hospital-based cancer registry and found that colorectal cancer patients with stroke onset within 3 months after cancer diagnosis had a worse prognosis. Our work suggests an interplay between KRAS and ischemic stroke that may offer insight into future treatments for cancer-associated stroke.