Oncolytic peptide LTX-315 plus an anti-CTLA-4 antibody induces a synergistic anti-cancer immune response in residual tumors after radiofrequency ablation of hepatocellular carcinoma

Abstract Preventing tumor recurrence after radiofrequency ablation (RFA) of malignant solid tumors with large size or in high-risk locations represents a great challenge. In this study, we explored the feasibility of using oncolytic peptide LTX-315 plus an anti-cytotoxic T lymphocyte antigen-4 (CTLA...

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Main Authors: Bo Sun, Jiayun Liu, Xiaocui Liu, Jing Li, Guilin Zhang, Tao Sun, Chuansheng Zheng, Xuefeng Kan
Format: Article
Language:English
Published: Nature Publishing Group 2025-04-01
Series:Cell Death and Disease
Online Access:https://doi.org/10.1038/s41419-025-07622-z
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author Bo Sun
Jiayun Liu
Xiaocui Liu
Jing Li
Guilin Zhang
Tao Sun
Chuansheng Zheng
Xuefeng Kan
author_facet Bo Sun
Jiayun Liu
Xiaocui Liu
Jing Li
Guilin Zhang
Tao Sun
Chuansheng Zheng
Xuefeng Kan
author_sort Bo Sun
collection DOAJ
description Abstract Preventing tumor recurrence after radiofrequency ablation (RFA) of malignant solid tumors with large size or in high-risk locations represents a great challenge. In this study, we explored the feasibility of using oncolytic peptide LTX-315 plus an anti-cytotoxic T lymphocyte antigen-4 (CTLA-4) antibody for inhibiting residual tumors after RFA of hepatocellular carcinoma (HCC). In in vitro experiment, the CD8+T cells from Hepa1-6 tumors, after being subjected to three different treatments (control, iRFA, iRFA + LTX-315), were extracted and were then co-cultured with Hepa1-6 cells and an anti-CTLA-4 antibody. The enzyme-linked immunospot, flow cytometry, and cell counting kit-8 assay were employed to assess the cytotoxicity of extracted CD8+T cells on Hepa1-6 cells. In in vivo experiment, different murine orthotopic HCC models were variously treated by: (1) pseudo iRFA + phosphate-buffered saline (PBS); (2) iRFA + PBS; (3) iRFA + LTX-315; (4) iRFA + anti-CTLA-4 antibody; and (5) iRFA + LTX-315 + anti-CTLA-4 antibody. The treatment effects were compared among different groups and were pathologically confirmed. The possible mechanisms of the combination treatment (LTX-315+anti-CTLA-4 antibody) for residual tumors after iRFA of HCC were explored. LTX-315 significantly reduced the PD-1 expression and significantly increased CTLA-4 expression of CD8+T cells in residual tumors, and additional treatment of anti-CTLA-4 antibody could significantly enhance the cytotoxicity of CD8+T cells for Hepa1-6 cells in vitro experiments. Compared with the other treatments, the combined treatment of LTX-315 with anti-CTLA-4 antibody achieved a better tumor response and longer survival, and it could synergistically activate the cGAS-STING pathway and elicit an immunogenic cell death, leading to a strong anti-tumor immunity after iRFA of HCC. The immunosuppressive microenvironment of residual tumors was significantly improved by the combination therapy with a significantly increased ratio of M1-like tumor-associated macrophages to M2-like tumor-associated macrophages, a significantly decreased infiltration of regulatory T cells and myeloid-derived suppressor cells, and a significantly lower expression of PD-1 and CTLA-4. Overall, the results of this study demonstrated that LTX-315 plus anti-CTLA-4 antibody could synergistically improve the immunosuppressive microenvironment of residual tumors and induce a strong anti-tumor immunity after iRFA of HCC. This combination treatment strategy may offer a new alternative to reduce the tumor recurrence after RFA of malignant solid tumors with large sizes or in high-risk locations.
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spelling doaj-art-8faf49d50c0d4b35b8e20c6ada361b5c2025-08-20T03:10:10ZengNature Publishing GroupCell Death and Disease2041-48892025-04-0116111410.1038/s41419-025-07622-zOncolytic peptide LTX-315 plus an anti-CTLA-4 antibody induces a synergistic anti-cancer immune response in residual tumors after radiofrequency ablation of hepatocellular carcinomaBo Sun0Jiayun Liu1Xiaocui Liu2Jing Li3Guilin Zhang4Tao Sun5Chuansheng Zheng6Xuefeng Kan7Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyDepartment of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyDepartment of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyDepartment of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyDepartment of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyDepartment of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyDepartment of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyDepartment of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyAbstract Preventing tumor recurrence after radiofrequency ablation (RFA) of malignant solid tumors with large size or in high-risk locations represents a great challenge. In this study, we explored the feasibility of using oncolytic peptide LTX-315 plus an anti-cytotoxic T lymphocyte antigen-4 (CTLA-4) antibody for inhibiting residual tumors after RFA of hepatocellular carcinoma (HCC). In in vitro experiment, the CD8+T cells from Hepa1-6 tumors, after being subjected to three different treatments (control, iRFA, iRFA + LTX-315), were extracted and were then co-cultured with Hepa1-6 cells and an anti-CTLA-4 antibody. The enzyme-linked immunospot, flow cytometry, and cell counting kit-8 assay were employed to assess the cytotoxicity of extracted CD8+T cells on Hepa1-6 cells. In in vivo experiment, different murine orthotopic HCC models were variously treated by: (1) pseudo iRFA + phosphate-buffered saline (PBS); (2) iRFA + PBS; (3) iRFA + LTX-315; (4) iRFA + anti-CTLA-4 antibody; and (5) iRFA + LTX-315 + anti-CTLA-4 antibody. The treatment effects were compared among different groups and were pathologically confirmed. The possible mechanisms of the combination treatment (LTX-315+anti-CTLA-4 antibody) for residual tumors after iRFA of HCC were explored. LTX-315 significantly reduced the PD-1 expression and significantly increased CTLA-4 expression of CD8+T cells in residual tumors, and additional treatment of anti-CTLA-4 antibody could significantly enhance the cytotoxicity of CD8+T cells for Hepa1-6 cells in vitro experiments. Compared with the other treatments, the combined treatment of LTX-315 with anti-CTLA-4 antibody achieved a better tumor response and longer survival, and it could synergistically activate the cGAS-STING pathway and elicit an immunogenic cell death, leading to a strong anti-tumor immunity after iRFA of HCC. The immunosuppressive microenvironment of residual tumors was significantly improved by the combination therapy with a significantly increased ratio of M1-like tumor-associated macrophages to M2-like tumor-associated macrophages, a significantly decreased infiltration of regulatory T cells and myeloid-derived suppressor cells, and a significantly lower expression of PD-1 and CTLA-4. Overall, the results of this study demonstrated that LTX-315 plus anti-CTLA-4 antibody could synergistically improve the immunosuppressive microenvironment of residual tumors and induce a strong anti-tumor immunity after iRFA of HCC. This combination treatment strategy may offer a new alternative to reduce the tumor recurrence after RFA of malignant solid tumors with large sizes or in high-risk locations.https://doi.org/10.1038/s41419-025-07622-z
spellingShingle Bo Sun
Jiayun Liu
Xiaocui Liu
Jing Li
Guilin Zhang
Tao Sun
Chuansheng Zheng
Xuefeng Kan
Oncolytic peptide LTX-315 plus an anti-CTLA-4 antibody induces a synergistic anti-cancer immune response in residual tumors after radiofrequency ablation of hepatocellular carcinoma
Cell Death and Disease
title Oncolytic peptide LTX-315 plus an anti-CTLA-4 antibody induces a synergistic anti-cancer immune response in residual tumors after radiofrequency ablation of hepatocellular carcinoma
title_full Oncolytic peptide LTX-315 plus an anti-CTLA-4 antibody induces a synergistic anti-cancer immune response in residual tumors after radiofrequency ablation of hepatocellular carcinoma
title_fullStr Oncolytic peptide LTX-315 plus an anti-CTLA-4 antibody induces a synergistic anti-cancer immune response in residual tumors after radiofrequency ablation of hepatocellular carcinoma
title_full_unstemmed Oncolytic peptide LTX-315 plus an anti-CTLA-4 antibody induces a synergistic anti-cancer immune response in residual tumors after radiofrequency ablation of hepatocellular carcinoma
title_short Oncolytic peptide LTX-315 plus an anti-CTLA-4 antibody induces a synergistic anti-cancer immune response in residual tumors after radiofrequency ablation of hepatocellular carcinoma
title_sort oncolytic peptide ltx 315 plus an anti ctla 4 antibody induces a synergistic anti cancer immune response in residual tumors after radiofrequency ablation of hepatocellular carcinoma
url https://doi.org/10.1038/s41419-025-07622-z
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