1. Intratumoral injection of mRNA encoding survivin in combination with STAT3 inhibitor stattic enhances antitumor effects.
- Author
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Li M, Xie Y, Zhang J, Zhou X, Gao L, He M, Liu X, Miao X, Liu Y, Cao R, Jia Y, Zeng Z, and Liu L
- Subjects
- Animals, Cell Line, Tumor, Injections, Intralesional, Myeloid-Derived Suppressor Cells immunology, Myeloid-Derived Suppressor Cells drug effects, Tumor Microenvironment drug effects, Mice, Female, Reactive Oxygen Species metabolism, CD8-Positive T-Lymphocytes immunology, Cell Proliferation, Inhibitor of Apoptosis Proteins genetics, Inhibitor of Apoptosis Proteins antagonists & inhibitors, Humans, Tumor Burden drug effects, Signal Transduction, Survivin genetics, Survivin antagonists & inhibitors, STAT3 Transcription Factor genetics, STAT3 Transcription Factor antagonists & inhibitors, STAT3 Transcription Factor metabolism, Mice, Inbred BALB C, RNA, Messenger genetics, Colonic Neoplasms therapy, Colonic Neoplasms immunology, Colonic Neoplasms pathology, Colonic Neoplasms genetics, Cyclic S-Oxides pharmacology
- Abstract
Intratumoral delivery of mRNA encoding immunostimulatory molecules can initiate a robust, global antitumor response with little side effects by enhancing local antigen presentation in the tumor and the tumor draining lymph node. Neoantigen-based mRNA nanovaccine can inhibit melanoma growth in mice by intratumoral injection. Myeloid-derived suppressor cells (MDSCs) suppress antitumor immune responses by secreting immunosuppressive agents, such as reactive oxygen species (ROS). Suppression of STAT3 activity by stattic may reduce MDSC-mediated immunosuppression in the TME and promote the antitumor immune responses. In this study, in vitro transcribed mRNA encoding tumor antigen survivin was prepared and injected intratumorally in BALB/c mice bearing subcutaneous colon cancer tumors. In vivo studies demonstrated that intratumoral survivin mRNA therapy could induce antitumor T cell response and inhibit tumor growth of colon cancer. Depletion of CD8
+ T cells could significantly inhibit survivin mRNA-induced antitumor effects. RT-qPCR and ELISA analysis indicated that survivin mRNA treatment led to increased expression of receptor activator nuclear factor-κB ligand (RANKL). In vitro experiment showed that MDSCs could be induced from mouse bone marrow cells by RANKL and RANKL-induced MDSCs could produce high level of ROS. STAT3 inhibitor stattic suppressed activation of STAT3 and NF-κB signals, thereby inhibiting expansion of RANKL-induced MDSCs. Combination therapy of survivin mRNA and stattic could significantly enhance antitumor T cell response, improve long-term survival and reduce immunosuppressive tumor microenvironment compared to each monotherapy. In addition, combined therapy resulted in a significantly reduced level of tumor cell proliferation and an obviously increased level of tumor cell apoptosis in CT26 colon cancer-bearing mice, which could be conducive to inhibit the tumor growth and lead to immune responses to released tumor-associated antigens. These studies explored intratumoral mRNA therapy and mRNA-based combined therapy to treat colon cancer and provide a new idea for cancer therapy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)- Published
- 2024
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