凋亡诱导配体TRAIL能特异性清除肿瘤细胞，但其重组蛋白稳定性差，靶向性弱，且肿瘤常抵抗TRAIL的凋亡诱导。利用阿霉素等药物能致敏肿瘤细胞，但也可导致非特异毒性。双硫仑DSF具有良好的安全性和高效的抗肿瘤活性，其在体内还能靶向瘤体富集。申请人前期以特异性识别PDGFRβ的人工抗体Z与TRAIL重组，制备了新型融合蛋白Z-TRAIL。通过靶向肿瘤新生血管周细胞，显著增强了对瘤体的药物递送。令人振奋的是DSF能协同增强Z-TRAIL的活性，且具有肿瘤细胞特异性。不仅如此，Z-TRAIL修饰PLGA纳米载体，能增强载体对肿瘤的主动靶向，并可共递送DSF协同杀伤肿瘤细胞。本项目拟进一步将二者联合，明确DSF协同Z-TRAIL的作用和机制；优化Z-TRAIL/DSF共递送纳米体系；评估其药代动力学和药效学。若获实施，将有望推出高效、安全和长效的共递送靶向纳米药物组合，克服肿瘤对TRAIL的抵抗。

Exhibition of superior and tumor-specific cytotoxicity is an ideal goal for anticancer therapy. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) belongs to tumor necrosis factor superfamily. TRAIL is able to induce apoptosis in tumor cells by engagement with its cognate death receptors while sparing normal cells. However, the lack of the stability as well as the tumor-homing ability of the recombinant soluble TRAIL impairs the antitumor effects in vivo. Importantly, it is well established that many tumor cells especially primary tumors are resistant towards TRAIL-induced apoptosis. Combining TRAIL with standard chemotherapeutic agents can bypass TRAIL resistance and sensitize tumor cells to TRAIL-induced apoptosis, but also lead to potential systematic toxicity.. Disulfiram (DSF) is a broad spectrum of cancer-killing agent with high therapeutic tolerability. Recently, a study released by Nature has confirmed up the drugs’ anticancer effects and also revealed the mechanism. The researchers found the metabolites of DSF preferentially accumulated in xenografted tumors and blocked the machinery for protein degradation and turnover inside tumor cells. This sparked our interest in comparison of the mechanism with that of TRAIL. Consequently, we presume that DSF can yield synergistic anticancer activity with TRAIL. To prove this hypothesis, we constructed and produced a tumor-homing TRAIL variant, designated Z-TRAIL, by fusion of TRAIL with an affibody recognizing PDGFRβ on pericytes of tumor vessels. We found co-treatment with Z-TRAIL and DSF rendered DSF able to synergize with this ligand and selectively enhanced cytotoxicity in tumor cells. Meanwhile, covalently attaching Z-TRAIL on the surface of PLGA nanoparticles not only facilitated particles’ active tumor-targeting ability, but also exhibited synergistic cytotoxicity in tumor cells by co-delivery of surface-displayed Z-TRAIL with DSF. Therefore, in this project, we will further investigate the reinforcing anticancer activity and the mechanism when co-delivery of Z-TRAIL with DSF to TRAIL-resistant tumor cells. Subsequently, we will optimize the drug dose and ratio of Z-TRAIL to DSF in nanoparticles and evaluate their pharmacokinetics and pharmacodynamics in vivo. We believe that the co-delivery nanoparticles will yield superior and long-lasting antitumor effects as well as good safety profile in vivo, and overcome TRAIL resistance to tumor cells.