Systems analysis identifies endothelin 1 axis blockade for enhancing the anti-tumor effect of multikinase inhibitor.

Multikinase inhibitors, such as sorafenib, are used for the treatment of advanced carcinomas but the response shows limited efficacy or varies a lot with patients. Here we adopted the systems approach combined with high-throughput data analysis to discover key mechanism embedded in the drug response. When analyzing the transcriptomic data from the Cancer Cell Line Encyclopedia (CCLE) database, endothelin 1 (EDN1) was enriched in cancer cells with low responsiveness to sorafenib. We found that the level of EDN1 is higher in the tissue and blood of hepatocellular carcinoma (HCC) patients showing poor response to sorafenib. In vitro experiment showed that EDN1 not only induces activation of angiogenic-promoting pathways in HCC cells but also stimulates proliferation and migration. Moreover, EDN1 is related with poor responsiveness to sorafenib by mitigating unfolded protein response (UPR), which was validated in both transcriptomic data analysis and in silico simulation. Finally, we found that endothelin receptor B (EDNRB) antagonists can enhance the efficacy of sorafenib in both HCC cells and xenograft mouse models. Our findings provide that EDN1 is a novel diagnostic marker for sorafenib responsiveness in HCC and a basis for testing macitentan, which is currently used for pulmonary artery hypertension, in combination with sorafenib in advanced HCC patients.