Project description: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.

Project description: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. 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.

Project description:THOC5, a member of the mRNA export complex, is essential for hematopoiesis in vivo and is required for CSF-1 induced macrophage differentiation, thereby playing a key role in the mRNA export of immediate early genes induced by CSF-1 stimulation. Hematopoiesis, growth, differentiation, and commitment to a restricted lineage are guided by a timely expressed set of cytokine receptors and their down-stream transcription factor genes. Transcriptional control mechanisms of gene expression during differentiation were mainly studied by focusing on the cis- and trans-element in promoters, however, the role of mRNA export machinery during differentiation have not been adequately examined. A member of the mRNA export complex, THOC5 which is a substrate for the macrophage-colony stimulating factor (CSF-1) receptor, ATM kinase, or protein kinase C, is an essential element in the maintenance of hematopoiesis in adult mice. Using tamoxifen inducible THOC5 knockout mice, we show here that the depletion of THOC5 impaired myeloid differentiation, but does not influence terminally differentiated organs. Furthermore, an in vitro study showed that the depletion of THOC5 in bone marrow cells results in abnormal CSF-1 induced macrophage differentiation. Transcriptome analysis using cytoplasmic RNA derived from macrophages reveals that only 99 genes were down-regulated 3 days after the depletion of THOC5, however, immediate early genes induced by CSF-1 stimulation, such as Ets family genes, and regulators of myeloid differentiation HoxA1, Id1, Id3 were THOC5 direct target mRNAs, suggesting that THOC5 plays a key role in myeloid differentiation. In each of two biological experiments (called rep1 and rep2 below) six different cytoplasmic RNA samples were generated from bone marrow derived macrophages. These different samples (conditions) correspond to: 1) Cells from ERT2 Cre control mice at day 0, 2) Cells from ERT2 Cre control mice at day 3 of differentiation, 3) Cells from ERT2 Cre control mice at day 3 of differentiation stimulated with tamoxifen, 4) Cells from ERT2 Cre Thoc5 (flox/flox) mice at day 0, 5) Cells from ERT2 Cre Thoc5 (flox/flox) mice at day 3 of differentiation, 6) Cells from ERT2 Cre Thoc5 (flox/flox) mice at day 3 of differentiation stimulated with tamoxifen. Day 0 samples of a given genotype were utilized as common reference in two microarrays and were accordingly co-hydridized against both 3-days differentiated samples (treated or none with tamoxifen) of the same genotype and biological experiment. Thus, four dual-color microarrays from each of the two biological replicate series were performed (giving rise to 8 dual-color microarrays in total). The complete set of microarrays from the second biological experiment (rep2) was performed with inverted labeling directions (dye-swap approach).

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THOC5 controls 3´end-processing of immediate early genes via interaction with CPSF100

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