Role of ursolic acid chalcone, a synthetic analogue of ursolic acid, in inhibiting the properties of CD133(+) sphere-forming cells in liver stem cells.

The expression of CD133 decreases with differentiation of tumor cell, indicating that CD133 is a specific marker for isolation and identification of CSCs. In the present study the effect of Ursolic acid chalcone (UAC) on CD133+ hepatocellular carcinoma cell (HCC CSCs) differentiation, their self-renewal, tumorigenic capacity and sensitivity to chemotherapeutic drugs was studied. The results demonstrated that UAC inhibits the expression of CD133+ in a dose and time-dependent manner in PLC/PRF/5 and Huh7 HCC cells. The inhibition was significant at 50 μM and on day 8. The percentage of CD133+ cells decreased from an initial 59.3% in PLC/PRF/5 to 37.1% and 78.2% in Huh7 to 59.2% on treatment with UAC. There was inhibition of Oct4, Tert, Bmi1, β-catenin, ABCG2, and tumor sphere-related gene Ep300. In addition it also decreased number of CK19-positive cells and increased number of CK8/18-positive cells. UAC treatment caused a decrease in self-renewal capability and increase in sensitivity to doxorubicin and vincristine drugs in CD133+ HCC CSCs. Therefore, UAC can be a potent therapeutic agent to target differentiation of CSC in HCC.