Genome wide effects of lithium on hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is the third most common cause of cancer mortality worldwide. Many studies have reported that hepatic stem cells are responsible for hepatocarcinogenesis. In this study, we did a thorough investigation to find out the genome wide and biological effects of lithium on HuH-7 cell line. Lithium caused proliferation inhibition on HCC cell lines, also reduced adhesion, increased motility and invasion in HuH-7 cells. The transcriptome analysis revealed the majority of lithium regulated genes related to metabolism and cell cycle. Importantly, effect of lithium on genes related to pluripotency and differentiation and the motility/invasion assays indicated that lithium treated cells gained a more pluripotent phenotype. We prove that LGR5 is a target gene of Wnt/b-catenin signalling in HCC which is known colon cancer stem cell marker. In addition, with using EpCAM and CD133 surface markers, we isolated HpCSC's from HuH-7 cell line and showed that this subpopulation have high pluripotency genes compared to the cells without these markers. Besides, we observed that EpCAM+/CD133+ cells were act similar to lithium treated cells. In this regard, EpCAM+/CD133+ cells were less proliferative and adhesive also more motile than EpCAM-/CD133- cells. We show that the EpCAM-/CD133- cells were sensitive to lithium similar to HuH-7 parental cells, whereas proliferation, motility and adhesion behavior of EpCAM+/CD133+ cells did not effected by lithium. Our study indicated that Wnt/b-catenin pathway effect metabolism and reprogrammed HpCSC?like properties and and it is of great importance that this is considered when developing new therapeutic strategies. Key Words; HCC, Lithium, HpCSC, Wnt/b-catenin signalling pathway