Targeted therapy of hepatocellular carcinoma via systemic injection of mesenchymal stem cells modified by NK4 in nude mice

Abstract

Objective To investigate anti-tumor effect of mesenchymal stem cells (MSCs) modified by NK4 on hepatocellular carcinoma. Methods MSCs modified by NK4 (LV-NK4-MSCs) were conducted by lentiviral transduction. Western blotting and enzyme linked immunosorbent assay (ELISA) were performed to analyze the expression level of NK4. SMMC-7721, MHCC-97H and HepG2 were supplemented with supernatant of LV-NK4-MSCs to observe the effect of NK4 on proliferation and apoptosis of hepatocellular carcinoma (HCC) cell lines. SMMC-7721 were used to establish an HCC subcutaneous mouse model. LV-NK4-MSCs were injected into tumor-bearing mice to visualize the distribution of MSCs in vivo. Tumor volume and survival time were monitored. ELISA was performed to detect the intratumoral level and plasma level of NK4. The expression of CD34, proliferation cell nuclear antigen (Ki-67) and vascular endothelial growth factor (VEGF) was analyzed by immunohistochemistry assay. Results LV-NK4-MSCs were conducted by lentiviral transduction and could secrete NK4 effectively. NK4 could inhibit the proliferation of three hepatocellular carcinoma (HCC) cells and promote apoptosis. MSCs mainly migrated to tumor site, rather than normal tissues. The intratumoral NK4 level in LV-NK4-MSCs group was higher than that in control group [(379.80±16.83) pg/ml vs. (29.68±5.59) pg/ml, P=0.021]. Tumor volume and the expression of CD34, Ki-67 and VEGF in the mice treated with LV-NK4-MSCs were significantly decreased than that in the control group [(211.40±14.13) mm3 vs. (457.70±93.74) mm3,P=0.009]. The median survival of mice treated with LV-NK4-MSCs was higher than that in the control group. Conclusion MSCs modified by NK4 could inhibit the proliferation of HCC cells. LV-NK4-MSCs could migrate to the tumor site in vivo, inhibit tumor growth and prolong survival. Key words: NK4; Hepatocellular carcinoma; Mesenchymal stem cells; Nude mice