BioProject

Hepatocellular carcinoma (HCC) is a frequent cancer with poor prognosis and with limited possibilities for anti-cancer treatment. More...

Hepatocellular carcinoma (HCC) is a frequent cancer with poor prognosis and with limited possibilities for anti-cancer treatment. Evidence has recently accumulated suggesting that multiple signaling pathways are activated in human cancer. It has been recently shown by exosome sequencing of HCC that 161 putative driver genes are associated with 11 recurrently altered pathways, suggesting that we need to inhibit these multiple pathways for HCC therapy. THOC5, a member of transcription/export (TREX) complex, that plays a role in less than 1% of mRNA processing in normal cells such as fibroblasts or macrophages, is not required for maintenance of mature hepatocytes. In this study, we have examined the role of THOC5 in human HCC. Enhanced THOC5 expression was not observed in differentiation grading 1 (G1) human HCC, but 78% of G2 and G3 exhibited increased levels of THOC5. Furthermore, the 50% depletion of THOC5 in hepatocellular carcinoma cell lines, Huh7 and HepG2 causes lipid accumulation and apoptosis. Transcriptome analysis using THOC5 depleted Huh7 and HepG2 cells revealed that 1049 and 837 genes were downregulated upon depletion of THOC5 in Huh7 and HepG2 cells, respectively. Among these genes, 396 were commonly downregulated in both cell lines. Some of these, such as tissue inhibitor of metalloproteinase 3 (TIMP3), tripartite motif containing 24 (TRIM24), ribosomal protein S6 kinase polypeptide 3 (RPS6KA3) and transmembrane emp24-like trafficking protein 10 (TMED10) are known to be fine tuners for several signal transduction pathways. The expression of these proteins was correlated with the THOC5 expression level in HCC. To inhibit multiple signaling pathways we are currently examining the effects of a combination of siRNAs against THOC5 target genes in HCC cell lines. Our data suggest that THOC5, which controls a set of genes that are involved in HCC malignancy can be a potential biomarker for HCC. In addition, THOC5 target gene, TMED10 may also be a novel biomarker of HCC. Furthermore, the suppression of the THOC5 gene per se or multiple THOC5 target genes may represent a novel strategy for cancer therapy. Overall design: Huh7 and HepG2 cells were infected with lentiviral THOC5 and control shRNAs. Five days after infection, total RNAs were isolated and subjected to microarray analysis. Less...