Vitexicarpin suppresses malignant progression of colorectal cancer through affecting c-Myc ubiquitination by targeting IMPDH2.

ABSTRACT

BACKGROUND: Colorectal cancer (CRC) is the second most common cause of cancer-related mortality and is characterised by extensive invasive and metastatic potential. Previous studies have shown that vitexicarpin extracted from the fruits of Vitex rotundifolia can impede tumour progression. However, the molecular mechanisms involved in CRC treatment are still not fully established. PURPOSE: Our study aimed to investigate the anticancer activity, targets, and molecular mechanisms of vitexicarpin in CRC hoping to provide novel therapies for patients with CRC. STUDY DESIGN/METHODS: The impact of vitexicarpin on CRC was assessed through various experiments including MTT, clone formation, EDU, cell cycle, and apoptosis assays, as well as a tumour xenograft model. CETSA, label-free quantitative proteomics, and Biacore were used to identify the vitexicarpin targets. WB, Co-IP, Ubiquitination assay, IF, molecular docking, MST, and cell transfection were used to investigate the mechanism of action of vitexicarpin in CRC cells. Furthermore, we analysed the expression patterns and correlation of target proteins in TCGA and GEPIA datasets and clinical samples. Finally, wound healing, Transwell, tail vein injection model, and tissue section staining were used to demonstrate the antimetastatic effect of vitexicarpin on CRC in vitro and in vivo. RESULTS: Our findings demonstrated that vitexicarpin exhibits anticancer activity by directly binding to inosine monophosphate dehydrogenase 2 (IMPDH2) and that it promotes c-Myc ubiquitination by disrupting the interaction between IMPDH2 and c-Myc, leading to epithelial-mesenchymal transition (EMT) inhibition. Vitexicarpin hinders the migration and invasion of CRC cells by reversing EMT both in vitro and in vivo. Additionally, these results were validated by the overexpression and knockdown of IMPDH2 in CRC cells. CONCLUSION: These results demonstrated that vitexicarpin regulates the interaction between IMPDH2 and c-Myc to inhibit CRC proliferation and metastasis both in vitro and in vivo. These discoveries introduce potential molecular targets for CRC treatment and shed light on new mechanisms for c-Myc regulation in tumours.