Sorafenib-Encapsulated Liposomes to Activate Hypoxia-Sensitive Tirapazamine for Synergistic Chemotherapy of Hepatocellular Carcinoma

Combination therapy with the synergistic effect is an effective way in cancer chemotherapy. Herein, an antiangiogenic sorafenib (SOR) and hypoxia-activated prodrug tirapazamine (TPZ)-coencapsulated liposome (Lip(TPZ/SOR)) is prepared for chemotherapy of hepatocellular carcinoma (HCC). SOR is a multi-target tyrosine kinase inhibitor that can inhibit tumor cell proliferation and angiogenesis. The antiangiogenesis effect of SOR can reduce oxygen supply and aggravate tumor hypoxia, which is able to activate hypoxia-sensitive prodrug TPZ, exhibiting the synergistic antitumor effect. Lip(TPZ/SOR) at different molar ratios of TPZ and SOR can significantly inhibit the proliferation of hepatocellular carcinoma cells. The mole ratio of TPZ and SOR was optimized to 2:1, which exhibited the best synergetic antitumor effect. The synergistic antitumor mechanism of SOR and TPZ was also investigated in vivo. After treated with SOR, the number of vessels was decreased, and the degree of hypoxia was aggravated in tumor tissues. What is more, in the presence of SOR, TPZ could be activated to inhibit tumor growth. The combination of TPZ and SOR exhibited an excellent synergistic antitumor effect. This research not only provides an innovative strategy to aggravate tumor hypoxia to promote TPZ activation but also paints a blueprint about a new nanochemotherapy regimen for the synergistic chemotherapy of HCC, which has excellent biosafety and bright clinical application prospects.