Microtubule disruption and apoptotic induction by Vibrio cholerae haemagglutinin protease: Implications for anticancer therapy in colon and gastric tumours.

Background and objectives Drug resistance and off-target toxicity remain major challenges in cancer therapy. Due to rapid proliferating nature of malignant cells, microtubule-targeting agents (MTAs) are widely used for chemotherapy, although their clinical efficacy is often limited by drug resistance and adverse effects. Objective of this study was to identify a novel therapeutic agent capable of selectively targeting microtubules in cancer cells while minimising toxicity to normal cells. Present study evaluates the chemotherapeutic potential of Vibrio cholerae haemagglutinin protease (HAP) as a novel MTA for gastric and colon cancers by investigating its role in microtubule degradation and apoptosis induction. Methods Effects of HAP were evaluated in human gastric and colon cancer cells using cellular and molecular assays. Time-dependent live-cell imaging was employed to assess HAP internalisation and co-localisation within intracellular organelles. Explant cultures derived from human tumour tissues were used to replicate the tumour microenvironment and validate therapeutic responses. Results HAP treatment activated protease-activated receptor 1 (PAR1), which is overexpressed in malignant cells, leading to an increase in intracellular reactive oxygen species (ROS) and facilitated HAP internalisation. Once internalised, HAP induced microtubule degradation through four mechanisms: ROS-mediated degradation of MAP2 and tau, destabilising microtubule network; enhancing tubulin-PARKIN interaction, enabling microtubule ubiquitination; and activation of lysosomal and proteasomal pathways to degrade microtubules. Collectively these events triggered apoptotic cascades in cancer cells and explant tissues, while normal healthy cells remained unaffected. Interpretation and conclusions HAP demonstrates strong potential as a selective anticancer therapeutic by inducing microtubule degradation and apoptosis without compromising viability of normal cells.