LX2-CM promotes proliferation, invasion and migration of liver cancer cells by activating c-Myc

Lejun Lin^1,#, Zhiying Xu^1,#, Bofeng Cao^2,*

¹Department of Nuclear Medicine, The Affiliated Yantai Yuhuangding Hospital of Qingdao University Medical College, Yantai, PR China - ²Department of Radiology, The Affiliated Yantai Yuhuangding Hospital of Qingdao University Medical College, Yantai, PR China

Objective: This study examines the mechanism of an LX2-conditioned medium (LX2-CM) in promoting the proliferation, invasion and migration of liver cancer cells. 

Methods: Human liver cancer cells HepG2 and hepatic stellate cells LX2 were cultured to obtain LX2-CM. The experiment was divided into a control group (DMEM-CM), control and medicated group (DMEM-CM with ERK1/2 pathway blocker U0126), research group (LX2-CM), and research and medicated group (LX2-CM with U0126), in which dimethyl sulfoxide was added to both the control and research groups, U0126 was added to the control and medicated group, and the research and medicated group was protected from light for 1.5 h. The transwell experiment was used to detect the changes in cell invasion ability and migration ability. The expression levels of vimentin, p-ERK1/2 and c-Myc of each group were measured using western blotting. 

Results: With the increase of U0126 concentration, the cell proliferation ability of both medicated groups showed a downward trend. Compared with the LX2-CM group, the cell proliferation ability of the DMEM group was significantly reduced at U0126 concentrations of 0 μmol/L, 5 μmol/L and 15 μmol/L (P<0.01). When the U0126 concentration was 25 μmol/L, the cells proliferative capacity in the DMEM group was significantly reduced compared with the LX2-CM group, but the difference between the two groups was not statistically significant (P>0.05). Compared with the control group, the cell invasion and metastasis ability of the control and medicated group were significantly reduced but were significantly improved in the research group (P<0.05). Compared with the research group, the cell invasion and metastasis ability of the research and medicated group were significantly reduced (P<0.05). The results of the western blotting showed that compared with the control group, the expression levels of vimentin, p-ERK1/2 and c-Myc in the control and medicated group were significantly reduced, and the levels in the research group significantly increased (P<0.05). Finally, compared with the research group, the expression levels of vimentin, p-ERK1/2 and c-Myc in the research and medicated group were significantly reduced (P<0.05). 

Conclusion: LX2-CM can activate c-Myc and can significantly promote the proliferation, invasion and migration of hepatocellular carcinoma cells, which may be closely related to the ERK1/2 signalling pathway.