TCOF1 promotes the colorectal cancer progression by stabilizing β-catenin.

Colorectal cancer (CRC) is one of the highest mortality rates worldwide, and various studies reported to the occurrence of CRC. In particular, the Wnt/β-catenin pathway is known to be a major factor in the progression of CRC and β-catenin involved in the expression of its downstream target genes. We searched for TCOF1 through sliver staining to identify a new binding partner for β-catenin and to investigate the role of the gene involved in CRC. Treacle Ribosome Biogenesis Factor 1 (TCOF1) is a nucleolar protein that regulates the transcription of ribosomal DNA (rDNA). There are many reports of genetic studies on TCOF1 mutations and defects, but its function in CRC remains unknown. We demonstrated that TCOF1 and β-catenin expression in tissue microarray (TMA) containing 101 individual CRC and 17 adjacent normal samples. Additionally, the effects of TCOF1 knockdown or overexpression were examined proliferation, colony formation assay, western blot, and quantitative real-time PCR (qRT-PCR). TCOF1 knockdown or overexpression regulates cell proliferation about three-fold and the phosphorylation of β-catenin, cyclin D1 expression levels. Besides, we discovered the mechanism through which TCOF1 regulates the stability of β-catenin was involved in degradation through proteasome using ubiquitination assay. Finally, we confirmed the interaction of TCOF1 with the tankyrase inhibitor NVP-TNKS656, which destabilizes β-catenin through in vitro and in vivo. Collectively, this study shows that significantly correlation was observed that TCOF1 and β-catenin were risk factor for tumor progression. The stability of β-catenin via regulating TCOF1 expression could be a potential strategy for therapeutic with CRC.