HapA protease targets PAR-1/2 to modulate ERK signalling and reduce cancer cell viability.

Recent studies reveal that Vibrio cholerae secretes virulence factors impacting host cell viability, though their effects on cancer cells remain unclear. However, the bacterial components and mechanisms influencing cancer cells remain largely unknown. This study investigated the effects of V. cholerae mutants lacking secreted proteins on carcinoma cells. We identified the hemagglutinin zinc-metalloprotease HapA as the main factor reducing cancer cell viability. HapA cleaves protease-activated receptors 1 and 2 on epithelial cancer cells at unique sites, unlike human proteases. This cleavage triggers an early and transient activation of the kinases MEK and ERK. Transient MEK and ERK activation initiates caspase 7, leading to apoptosis and reduced viability in epithelial cancer cells. Our findings underscore the significance of human protease-activated receptors as targets for bacterial protease HapA. Furthermore, we demonstrate that selective cleavage of PAR-1/2 by HapA adjusts MEK-ERK signalling dynamics, suggesting potential new avenues for the development of novel anticancer therapies. Understanding how pathogens like V. cholerae interact with cancer cells sheds light on potential mechanisms underlying cancer progression and suggests new therapeutic targets for cancer treatment.