Effect of human mesenchymal stem cells on hepatoma cell line

Human mesenchymal stem cells (hMSCs) are mostly studied for their potential clinical use. Little is known about the underlying molecular mechanisms that link hMSCs to the targeted inhibition of tumor cells. The present study was conducted to evaluate the tumor suppressive effects of human mesenchymal stem cells (hMSCs) on human hepatoma cell line (HepG2) and their signaling mechanisms. To fulfill this objective, the influence of hMSCs on genes concerned with apoptosis, mitogenesis as well as on the proliferation of HepG2 cell line was investigated using either hMSCs-conditioned or using hMSCs and HepG2 co-culture conditioned media. Cell survival was evaluated using cell proliferation (MTT) assay kit. Gene expression of survivin, proliferating cell nuclear antigen (PCNA), β-Catenin, telomerase and VEGF was assessed by real time reverse transcription-polymerase chain reaction (RT-PCR). HpG2 cells cultured with either hMSCs-conditioned media or with hMSCs&HepG2 co-culture conditioned media showed decreased proliferation and decreased expression of survivin, PCNA, β-Catenin and telomerase. However, both media had increased expression of VEGF. Treatment of HepG2 cells by either hMSCs conditioned media or by hMSCs and HepG2 co-culture condition media led to a significant decrease in cell proliferation and down regulation of genes concerned with antiapoptosis, mitogenesis, and cell proliferation. This indicates that hMSCs can suppress tumorigenesis through factors produced in their conditioned media.