ASLAN-002

Efferocytosis of apoptotic cancer cells by tumor-associated macrophages or other phagocytes is reported to promote tumor immunosuppression by preventing them from secondary necrosis, which would lead to the release of intracellular components and thus enhanced immunogenicity. Therefore, current apoptosis-inducing cancer treatments (e.g., chemotherapy and radiotherapy) are less satisfactory in eliciting antitumor immunity. Herein, a nanoparticulate inhibitor of efferocytosis is prepared by encapsulating BMS777607, a hydrophobic inhibitor of receptors in macrophages responsible for phosphatidylserine-dependent efferocytosis, with biocompatible poly(lactic-co-glycolic acid) and its amphiphilic derivatives. The yielded nano-BMS can inhibit the efferocytosis of apoptotic cancer cells, thus redirecting them to immunogenic secondary necrosis. As a result, intratumorally injected nano-BMS is capable of activating both innate and adaptive antitumor immunity to achieve greatly improved therapeutic responses, when synergized with nonimmunogenic chemotherapy by cisplatin, immunogenic chemotherapy by oxaliplatin, or radiotherapy by external beams. Moreover, we further demonstrate that the inhalation of nano-BMS could significantly promote the efficacy of cisplatin chemotherapy to suppress tumor lung metastases. Therefore, this study highlights a general strategy to potentiate the immunogenicity of different cancer treatments by suppressing efferocytosis-propelled tumor immunosuppression, showing tremendous clinical potential in rescuing existing cancer therapies for more effective treatment.

Cancer is a leading cause of death in humans. Molecular targeted therapy for cancer has become a research hotspot as it is associated with low toxicity and high efficiency. In this study, a total of 36 derivatives of 4-(4-aminophenoxy)pyridinamide were designed and synthesized, based on the analysis of the binding patterns of cabozantinib and BMS-777607 to MET protein. Most target compounds exhibited moderate to excellent antiproliferative activity against three different cell lines (A549, HeLa and MCF-7). A total of 7 compounds had stronger inhibitory activities than cabozantinib, and the IC₅₀ value of the most promising compound 46 was 0.26 μM against the A549 cells, which was 2.4 times more active than that of cabozantinib. The structure-activity relationship of the target compounds was analyzed and summarized, and the action mechanism was discussed. The acridine orange (AO) staining assay and cell cycle apoptosis revealed that compound 46 dose-dependently induced apoptosis of A549 cells, and blocked the cells mainly in G0/G1 phase. The IC₅₀ value of compound 46 on c-Met kinase was 46.5 nM. Further docking studies and molecular dynamics simulations signaled that compound 46 formed four key hydrogen bonds to c-Met kinase, and these key amino acids played a major role in binding free energy. In addition, compound 46 also showed good pharmacokinetic characteristics in rats. In conclusion, compound 46 is a promising antitumor agent.