TP53INP2 (tumor protein p53-inducible nuclear protein 2), known as an autophagy protein, is essential for regulating transcription and starvation-induced autophagy, which plays a crucial role in the oncogenesis and progression of various cancers. The present study aims to investigate the expression pattern, function and prognostic value of TP53INP2 in colorectal cancer (CRC). Here, we report that low expression of TP53INP2 correlates with poor survival in CRC patients. TP53INP2 was significantly downregulated in CRC tissues compared with adjacent tissues. As the malignancy of CRC progresses, the expression level of TP53INP2 gradually decreased. Knockdown of TP53INP2 promoted CRC cell proliferation and tumor growth in mice. Mechanistically, TP53INP2 deficiency decreased phosphorylation of β-catenin on S33, S37, and T41, resulting in increased accumulation of β-catenin and enhanced nuclear translocation and transcriptional activity. Moreover, we further demonstrated that TP53INP2 sequestered TIM50, thereby inhibiting its activation of β-catenin. Taken together, our findings indicate that the downregulation of TP53INP2 promotes CRC progression by activating β-catenin and suggest that TP53INP2 may be a candidate therapeutic target for CRC.
Keywords: Colorectal cancer; TIM50; TP53INP2; Tumor progression; β-catenin.
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