Lei Lei,Wenbin Dai,Jinchao Zhao,Angfeng Jiang,Haisheng Peng,Qiao Jin,Xiaojing Li,Zhe Tang
Photodynamic therapy (PDT) is a promising cancer therapy modality by generating reactive oxygen species (ROS) and triggering immunogenic cell death. However, the therapeutic effect of PDT is strongly limited by tumor hypoxia and immunosuppressive landscape. Herein, a pH-sensitive nanosized covalent–organic polymer (COP), composed of the photosensitizer porphyrin and pyruvate kinase inhibitor vitamin K3 (VK3), is designed to overcome these issues. The signal transducer and activator of transcription 3 (STAT3) inhibitor WP1066 is further encapsulated into COPs to form a WP1066-loaded COP (TVW). As an inhibitor of pyruvate kinase, VK3 can reduce intracellular oxygen consumption by inhibiting the glycolytic pathway, leading to the alleviation of the tumor hypoxic microenvironment. The relief of tumor hypoxia by VK3 enhances photodynamic cytotoxicity by generating more ROS. Meanwhile, STAT3 acts as a major regulator of PD-L1, a key inhibitor that promotes immune escape. WP1066 effectively inhibits the expression of STAT3 and reduces PD-L1 expression, thereby significantly inhibiting tumor immune escape and enhancing antitumor efficacy in a synergistic manner. The antitumor capacity of photodynamic immunotherapy is extensively investigated in a murine subcutaneous hepatocellular carcinoma model. This photo-immunotherapy may provide an effective combination regimen for the efficient treatment of solid tumors such as hepatocellular carcinoma.
Tumor hypoxia is a critical driver of cancer progression, metastasis, and therapy resistance, posing significant challenges in effective cancer treatment. Hypoxia-activable prodrugs offer a promising strategy to target tumors in low-oxygen conditions, but their efficacy is often hindered by intrinsic properties and extrinsic cues. In this study, we developed a dual-prodrug nanoassembly system (CPPA) composed of a hypoxia-triggerable camptothecin (CPT)-based dimeric prodrug (CP) and a lipid-conjugated STAT3 antisense oligonucleotide (ASO) prodrug (PA), aiming to enhance tumor-targeted chemotherapy and overcome the immune evasion within the tumor microenvironment. The CPPA self-assemble into stable nanomicelle capable of co-delivering both agents directly to the tumor site, where the hypoxia-triggered release of CPT induces immunogenic cell death (ICD) while STAT3 inhibition enhances immune response. In murine breast cancer models, CPPA demonstrated superior therapeutic efficacy by improving tumor cell killing, promoting immune cell infiltration, and modulating the immunosuppressive tumor microenvironment. This combination therapy not only reversed drug resistance but also prevented the formation of the pre-metastatic niche, significantly inhibiting tumor progression and metastasis. These findings highlight the potential of CPPA as an effective strategy for enhancing cancer immunotherapy, offering a promising approach to address the complex challenges of tumor hypoxia, immune evasion, and resistance to chemotherapy.