This new research, published in the Genes & Diseases journal by a team from the South China University of Technology School of Medicine, investigated the mechanistic role of the chloride channel accessory 4 (CLCA4) in governing CRC stemness and its potential to sensitise tumours to immunotherapy.

Clinical cohort analyses and extensive in vitro experiments revealed that CLCA4 expression is significantly downregulated in chemoresistant CRC cells and CD133⁺/CD44⁺ colorectal CSCs, with this deficiency strongly correlating with advanced tumour progression and poor patient survival.

By establishing stable CLCA4-overexpressing CRC cell lines, researchers demonstrated a dramatic reduction in tumorsphere formation, cell motility, and the expression of core stemness genes such as Bmi-1 and Oct4.

Mass spectrometry and immunoprecipitation analyses identified the underlying molecular mechanism, revealing that CLCA4 directly interacts with vimentin to promote its degradation, which subsequently inactivates the FAK signalling pathway.

This targeted suppression of the vimentin-FAK axis critically halts CSC self-renewal and expansion.

Conversely, restoring vimentin or activating FAK successfully reversed the tumour-suppressive effects of CLCA4, confirming this highly specific signalling network.

Remarkably, in vivo mouse xenograft and liver metastasis models confirmed that elevating CLCA4 expression not only impaired tumour growth but also profoundly reshaped the tumour immune microenvironment, sensitising CRC to anti-PD-1 immunotherapy.

CLCA4 overexpression triggered the secretion of the chemokine CXCL10, leading to a massive infiltration of cytotoxic CD8⁺ T cells and transforming the tumours from an immunosuppressive to an immunostimulatory state.

Consequently, the combination of CLCA4 overexpression and anti-PD-1 therapy significantly reduced both primary tumour volume and hepatic metastatic lesions compared to monotherapy alone.

While these collective data robustly highlight the vital role of targeting CSC properties to overcome adaptive immune resistance, additional studies are necessary to translate these findings into clinical applications.

In conclusion, this study identifies CLCA4 as a dual-function regulator that suppresses CSC-driven tumour progression while simultaneously enhancing anti-tumour immunity.

Targeting the CLCA4 signalling axis may offer a promising therapeutic strategy to overcome resistance and improve immunotherapy outcomes in colorectal cancer.

Source: Compuscript Ltd