Experimental Studies On Anticancer Effect Of Oncostatin M Combined With Salinomycin On Liver Cancer Stem Cells

Hepatocellular carcinoma(HCC) is one of the most common and fatal tumors in the world. HCC affects more than a million people each year and ranks third in cancer mortality worldwide. HCC is not sensitive to chemotherapy and radiotherapy. It is easy to recur after surgery, and has a poor prognosis.Therefore, it is urgent to develop a new treatment strategies for HCC. The emergence of cancer stem cells’ theory has opened up a new way for the treatment of HCC. Cancer stem cells is a little cell subsets in the cancer cells. They has the ability of self-renewal and divide infinitely.They are more resistant to chemotherapy and radiotherapy than the ordinary cancer cells and related to tumor recurrence and regeneration closely. Therefore, targeting removal of cancer stem cells may be the key to cure tumor. At present, differentiation therapy, one of the therapies targeted cancer stem cells, has more research.Oncostatin M(OSM) is a multifunctional regulatory factor. The study found that OSM can induce the differentiation of liver cancer stem cells and increase the sensitivity to the traditional chemotherapeutic agent 5-fluorouracil(5Fu).Salinomycin(Sal) is a veterinary antibiotic. In recent year, It has received more and more attentions due to its inhibition of cancer stem cells. Studies have shown that salinomycin can reduce the proliferation of liver cancer cells and induce apoptosis,while lowering the percentage of CD133~+ cell subpopulations. In this study, we isolated CD133~+ Hep G2 cells as the source of liver cancer stem cells by immunomagnetic beads technique and investigate whether combination OSM and Sal could induce the differentiation of liver cancer stem cells significantly.Results show that CD133~+ Hep G2 cells were cultivated in the serum-free DMEM/F12 medium with the 20ng/ml EGF, 20ng/ml b FGF and 2% B27. The cells were suspended and formed tumor microspheres gradually, the clone formed as well as in the soft agar medium, which then adhered to grow in serum medium. OSM, Sal,combination OSM and Sal treatment were given to the liver cancer stem cells, results show that the combination group inhibited the growth and the invasion ability of livercancer stem cells significantly; We detected apoptosis by Annexin-V-FITC stain, JC-1and Western Blot, and found that combination OSM and Sal received more apoptotic cells, caused a bigger decrease of mitochondrial membrane potentia and more expression of caspase3 than either OSM or Sal, these suggest that combination OSM and Sal could induce more apoptotic cells; Further, we detected the differentiation associated markers of liver cancer stem cell, results show that combination OSM and Sal can decrease the expression of CD133 and some special gene of cancer stem cells,produce a higher level of AFP and a lower level of ALB significantly, these suggest that combination OSM and Sal could induce more differentiation of liver cancer stem cells.Taken together, our data suggest the treatment of combination OSM and Sal could efficiently inhibite the growth of liver cancer stem cells significantly, induced more differentiation of liver cancer stem cells, promote more apoptotic cells. Our finding provides a new way for targeting therapy of liver cancer stem cells.