Abstract 3829: TCIRG1, T-cell immune regulator 1, functions as a metastatic enhancing gene in liver tumorigenesis

Recurrence and metastasis are a major challenge in the management of hepatocellular carcinoma (HCC) patients after HCC resection. In order to identify metastatic molecular signature, we performed comparative gene expression profiling analysis with recurred HCC tissues from HCC patients who underwent partial or total hepatectomy and non-metastatic primary HCC. From this, we were able to recapitulate molecular signatures associate with HCC recurrence, and found that TCIRG1 (T-Cell Immune Regulator 1) was one of the aberrantly overexpressed gene elements in recurred HCC patients with total hepatectomy. We then observed that TCIRG1 is significantly overexpressed in TCGA-LIHC (Liver Hepatocellular Carcinoma Dataset of The Cancer Genome Atlas), and high expression of TCIRG1 was significantly associated with poor prognosis of HCC patients in 5-year disease-free. TCIRG1 knockdown suppressed tumor cell growth and proliferation in Huh7 and SNU475, liver cancer cell lines. From flow cytometric analysis for cell cycle analysis and cell death, we observed that TCIRG1 knockdown caused a significant increase of G1/S phase, and also induced programmed cell death processing in liver cancer cells. TCIRG1 knockdown also reduced the metastatic potential of HCC cells by selectively regulating epithelial-mesenchymal transition (EMT) regulatory proteins, E-cadherin, N-cadherin, Vimentin, Fibronectin, Snail and Slug, in liver cancer cells. In addition, sustained expression of TCIRG1 in liver cancer cell line reduced tumor growth rate in mouse xenograft model. Moreover, targeted-disruption of TCIRG1 significantly attenuated the metastatic potential of ras-transformed NIH-3T3 cells in vitro and in vivo. In conclusion, our findings suggest that TCIRG1 functions as metastatic enhancing gene by modulating cellular growth, death, and EMT in liver cancer cells providing TCIRG1 as a therapeutic target for the treatment of liver malignancy and metastasis. Citation Format: Hee Doo Yang, Jung Woo Eun, Qingyu Shen, Hyung Seok Kim, Sang Yean Kim, Suk Woo Nam. TCIRG1, T-cell immune regulator 1, functions as a metastatic enhancing gene in liver tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3829. doi:10.1158/1538-7445.AM2017-3829