The insufficient activation and impaired effector functions of T cells in the immunosuppressive tumor microenvironment (TME) substantially reduces the immunostimulatory effects of radiotherapy. Herein, a multifunctional nanoradiosensitizer is established by integrating molecularly engineered aptamer precursors into cisplatin-loaded liposomes for enhancing radio-immunotherapy of solid tumors. Exposure to ionizing radiation (IR) following the nanoradiosensitizer treatment would induce pronounced immunogenic death (ICD) of tumor cells through cisplatin-mediated radiosensitization while also trigger the detachment of the aptamer precursors, which further self-assemble into PD-L1/PD-1-bispecific aptamer-based T cell engagers (CA) through the bridging effect of tumor-derived ATP to direct T cell binding onto tumor cells in the post-IR TME in a spatial-temporally programmable manner. The CA-mediated post-IR tumor-T cell engagement could override the immunosuppressive barriers in TME and enhance T cell-mediated recognition and elimination of tumor cells while minimizing systemic toxicities. Overall, this work offers an innovative approach to enhance the radio-immunotherapeutic efficacy in the clinics.
Yan Chen,Ming Zhang,Zhifang Liu,Ning Zhang,Qingpeng Wang
Tumor microenvironment (TME) is a pivotal factor driving the tumor metastasis and leading to the failure of tumor therapy. Here, a series of ursodeoxycholic acid platinum(IV) conjugates with potency in remodeling the TME through suppressing JAK2/STAT3 signaling was developed. A candidate was screened out, which displayed potent antiproliferative and antimetastatic performance both in vitro and in vivo. It displayed superior pharmacokinetic properties compared to cisplatin. Serious DNA injury was induced, and then mitochondria-mediated apoptosis was initiated through the Bcl-2/Bax/Caspase3 pathway. The JAK2/STAT3 and TGF-β1 signaling pathways were remarkably inhibited, and pro-death autophagy was subsequently promoted. The inflammatory and hypoxic TME was suppressed by downregulating COX-2, MMP9, and HIF-1α, which resulted in inhibited angiogenesis in tumors by inhibiting the HIF-1α/VEGFA axis. Additionally, the immunosuppressive TME was reversed by blocking the immune checkpoint PD-L1, further improving the density of CD3+ and CD8+ tumor-infiltrating lymphocytes, and promoting macrophage polarization from M2- to M1-type.
Kai Xie,Xing-Yun Lu,Hou Zhu,Lin-Yuan Zhu,Rong-Tao Li,Rui-Rong Ye
A series of Ir(III)–naproxen (NPX) conjugates with the molecular formula [Ir(C^N)2bpy(4-CH2ONPX-4′-CH2ONPX)](PF6) (Ir-NPX-1–3) were designed and synthesized, including C^N = 2-phenylpyridine (ppy, Ir-NPX-1), 2-(2-thienyl)pyridine (thpy, Ir-NPX-2) and 2-(2,4-difluorophenyl)pyridine (dfppy, Ir-NPX-3). Cytotoxicity tests showed that Ir-NPX-1–3 exhibited excellent antitumor activity, especially in A549R cells. The cellular uptake experiment showed that the complexes were mainly localized in mitochondria, and induced apoptosis in A549R cells by damaging the structure and function of mitochondria. The main manifestations are a decrease in the mitochondrial membrane potential (MMP), an increase in reactive oxygen species (ROS) levels, and cell cycle arrest. Furthermore, Ir-NPX-1–3 could inhibit the migration and colony formation of cancer cells, demonstrating potential anti-metastatic ability. Finally, the anti-inflammatory and immunological applications of Ir-NPX-1–3 were verified. The downregulation of cyclooxygenase-2 (COX-2) and programmed death-ligand 1 (PD-L1) expression levels and the release of immunogenic cell death (ICD) related signaling molecules such as damage-associated molecular patterns (DAMPs) (cell surface calreticulin (CRT), high mobility group box 1 (HMGB1), and adenosine triphosphate (ATP)) indicate that these Ir(III) –NPX conjugates are novel ICD inducers with synergistic effects in multiple anti-tumor pathways.
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