Knockdown of tripartite motif 59 (TRIM59) inhibits proliferation in cholangiocarcinoma via the PI3K/AKT/mTOR signalling pathway.

AIM

We analysed multiple microarray datasets in the Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus (GEO) DataSets for messenger RNAs (mRNAs) whose expression is apparently increased in human cholangiocarcinoma (CCA) samples, compared with that in the adjacent normal biliary epithelial tissue. The results revealed that the expression of tripartite motif-containing 59 (TRIM59) was significantly increased in the CCA tissue samples. TRIM59 is a member of the tripartite motif (TRIM) protein family, which contains a highly conserved N-terminal-an interesting new gene (RING) domain regulating transcriptional factors and tumorigenesis. In the present study, we investigated the effects of TRIM59 expression on tumour growth in CCA.

MATERIALS AND METHODS

After analyzing the microarray datasets from the TCGA database and GEO DataSets, we screened out 291 target genes, which are significantly overexpressed in CCA tissues, and TRIM59 was one of them. The quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), Western blotting, and immunohistochemistry were performed to determine the expression of TRIM59 in CCA tissues (n = 65) and cell lines. Kaplan-Meier survival analysis was conducted to assess the prognosis of TRIM59 in patients with CCA. A specific siRNA (siRNA-1008) was used to inhibit the expression of TRIM59 in HCCC9810 and HUCCT1 cell lines. The effects of TRIM59 silencing on cell proliferation were assessed by the CCK-8, colony-formation, and EDU incorporation assays. Furthermore, the effects of TRIM59 knockdown on cell apoptosis and cell cycle were determined by flow cytometry. The in vivo effects were evaluated using a mouse tumorigenic model. Western blotting was also performed to verify the relationship between knockdown of TRIM59 and activation of the PI3K/AKT/mTOR pathway.

RESULTS

TRIM59 was highly expressed in CCA tissues. The knockdown of TRIM59 obviously reduced the proliferation and colony formation abilities of CCA cells in vitro and in vivo. Furthermore, the cell apoptosis analysis results showed that TRIM59 silencing apparently promoted CCA cell apoptosis by the mitochondrial pathway. Our preliminary results indicate that the down-regulation of TRIM59 levels might restrict the PI3K/AKT/mTOR signalling pathway.

CONCLUSIONS

Our study revealed that TRIM59 is up-regulated in CCA tissues and cell lines and promoted CCA cell proliferation, possibly by affecting the PI3K/AKT/mTOR signalling pathway.