USP7 facilitates deubiquitination of LRRC42 in colorectal cancer to accelerate tumorigenesis and augment Wnt/β-catenin signaling.

Colorectal cancer is a prevalent malignancy with an increasing incidence worldwide. Leucine-rich repeat-containing protein 42 (LRRC42) is known to be dysregulated in tumor tissues, yet its role in colorectal cancer remains largely unexplored. Herein, the function of LRRC42 in colorectal cancer was investigated using clinical samples, cellular experiments, animal models, and multiple omics techniques. The results demonstrated that LRRC42 was highly expressed in colorectal cancer tissues and was associated with poor clinical outcomes. Silencing LRRC42 suppressed cell proliferation, induced G0/G1 phase arrest, and promoted apoptosis by reducing Bcl2 expression while elevating the expression of Bax, cleaved PARP and cleaved caspase 3. Conversely, LRRC42 overexpression exhibited the opposite effects. Consistent findings were observed in vivo. Additionally, ubiquitin specific peptidase 7 was identified as a potential LRRC42-interacting protein through immunoprecipitation-mass spectrometry, with ubiquitin specific peptidase 7 stabilizing LRRC42 expression by promoting its deubiquitination. Notably, LRRC42 overexpression partially reversed the effects of ubiquitin specific peptidase 7 silencing on tumor cell proliferation and apoptosis. mRNA sequencing analysis revealed that differentially expressed genes in LRRC42 overexpressing cells were linked to Wnt signaling pathway, suggesting that LRRC42 overexpression may activate this pathway. Furthermore, LRRC42 was proved to elevate the levels of ki67, cyclin D1 and WNT3, while reducing the level of p-β-catenin. These findings suggest that LRRC42 perhaps serve as a potential oncogenic factor in colorectal cancer, regulated by ubiquitin specific peptidase 7 and capable of activating Wnt/β-catenin signaling pathway.