Targeting Bmi1 for Enhancing Anoikis Sensitivity and Inhibiting Metastasis in Colorectal Cancer.

Abstract

Patients diagnosed with advanced metastatic colorectal cancer (CRC) confront a bleak prognosis characterized by low survival rates. Anoikis, the programmed apoptosis resistance exhibited by metastatic cancer cells, is a crucial factor in this scenario. We employed bulk flow cytometry and RT-qPCR assays, conducted in vivo experiments with mice and zebrafish, and analyzed patient tissues to examine the effects of the B cell-specific Moloney murine leukemia virus insertion site 1 (Bmi1)-midkine (MDK) axis on the cellular response to anoikis. Bmi1 is pivotal in tumorigenesis. This study elucidated the involvement of Bmi1 in conferring anoikis resistance in CRC and explored its downstream targets associated with metastasis. Elevated levels of Bmi1 expression correlated with distant metastasis in CRC. Suppression of Bmi1 significantly diminished the metastatic potential of CRC cells. Inhibition of Bmi1 led to an increase in the proportion of apoptotic SW620 cells detached from the matrix. This effect was further enhanced by the addition of irinotecan, a topoisomerase I inhibitor. Furthermore, Bmi1 was found to synergize with MDK in modulating CRC viability, with consistent expression patterns observed in in vivo models and clinical tissue specimens. In summary, Bmi1 acted as a regulator of CRC metastatic capability by conferring anoikis resistance. Additionally, it collaborated with MDK to facilitate invasion and distant metastasis. Targeting Bmi1 may offer a promising adjunctive therapeutic strategy when administering traditional chemotherapy regimens to patients with advanced CRC.