Glycycoumarin Sensitizes Liver Cancer Cells to ABT-737 by Targeting De Novo Lipogenesis and TOPK-Survivin Axis

Glycycoumarin (GCM) is a representative of bioactive coumarin compounds isolated from licorice, an edible and medicinal plant widely used for treating various diseases including liver diseases. The purpose of the present study is to examine the possibility of GCM as a sensitizer to improve the efficacy of BH3 mimetic ABT-737 against liver cancer. Three liver cancer cell lines (HepG2, Huh-7 and SMMC-7721) were used to evaluate the in vitro combinatory effect of ABT-737/GCM. HepG2 xenograft model was employed to assess the in vivo efficacy of ABT-737/GCM combination. Results showed that GCM was able to significantly sensitize liver cancer cells to ABT-737 in both in vitro and in vivo models. The enhanced efficacy by the combination of ABT-737 and GCM was attributed to the inactivation of T-LAK cell-originated protein kinase (TOPK)-survivin axis and inhibition of de novo lipogenesis. Our findings have identified induction of TOPK-survivin axis as a novel mechanism rendering cancer cells resistant to ABT-737. In addition, ABT-737-induced platelet toxicity was attenuated by the combination. The findings of the present study implicate that bioactive coumarin compound GCM holds great potential to be used as a novel chemo-enhancer to improve the efficacy of BH3 mimetic-based therapy.