Microwave ablation combined with anti-PD-1/CTLA-4 therapy induces an antitumor immune response to renal cell carcinoma in a murine model

Microwave ablation of non-small cell lung cancer enhances local T-cell abundance and alters monocyte interactions

BACKGROUND

Minimally invasive thermal therapies show great prospect in non-small cell lung cancer (NSCLC) treatment. However, changes in immune cell populations following microwave ablation (MWA) in NSCLC microenvironment are not fully revealed.

OBJECTIVE

The present study was conducted to identify changes in immune cell populations and analyse dysregulated genes in immune cells after MWA in NSCLC microenvironment.

METHODS

The patients received fractionated MWA in two treatments separated by 3 weeks. Tumor biopsy samples were obtained through core-needle biopsy before each fractionated MWA procedure at the same site and used for single-cell RNA sequencing with the 10x Genomics pipeline.

RESULTS

A total of 9 major cell types were identified after MWA, which include neutrophils, T cells, B cells, monocytes, epithelial cells, chondrocytes, macrophages, tissue stem cells, and endothelial cells. After MWA, the tumor tissue exhibited an increased proportion of T cells. MWA altered gene expression in each cell cluster at the single-cell level. Cell trajectory analysis revealed that the cells at the starting point were most like T helper cells, naïve T cells, and regulatory T cells; they then developed into anergic T cells, T follicular cells, natural killer T cells, T memory cells, and exhausted T cells, and finally ended as γδ T cells and cytotoxic T cells. Moreover, after MWA, more interaction between monocytes and T cells (or B cells) were identified.

CONCLUSIONS

MWA increases local T-cell abundance and alters monocyte interactions, thereby reshaping the tumor microenvironment. This study lays a foundation for investigating dysregulated genes that may contribute to the MWA-induced immune response in NSCLC.

WHAT IS ALREADY KNOWN ON THIS TOPIC

Thermal ablation may change the immune profiles of patients by activating various steps in the cancer immunity cycle. However, changes in immune cell populations following MWA of NSCLC have not been fully reported.

WHAT THIS STUDY ADDS

After MWA, an increase in interactions between monocytes and T cells intratumorally was observed, which promoted antitumor immunity.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY

The current study illuminates the MWA-caused systemic immune response in NSCLC, which may help to identify the dysregulated genes involved in the MWA-caused immune response.

Microwave ablation combined with immune checkpoint inhibitor enhanced the antitumor immune activation and memory in rechallenged tumor mouse model

Microwave ablation (MWA) is a super minimally invasive therapeutic approach that has been widely applied in the treatment of non-small cell lung cancer (NSCLC). Although MWA can elicit antitumor immune responses, these immune responses are not relatively steady and insufficient to completely clear recurrence tumor cells within the body. Immunotherapy monotherapy has shown low clinical efficacy in the treatment of advanced NSCLC. MWA combined with immune checkpoint inhibitors (ICIs) is a promising therapeutic approach. However, the mechanism of synergic effect remains elusive. In this study, we have conducted a retrospective analysis of the clinical outcomes of MWA combined with ICIs, finding that the combinational therapy yielded superior Objective Response Rate and longer Progression-Free Survival. In preclinical models, we established a tumor rechallenged model to address post-MWA recurrence and to delve into the underlying mechanisms of the combined therapy. We observed that the combined treatment (MWA + PD-L1 blockade therapy) effectively addressed the issue of tumor recurrence in tumor rechallenged model. The combinational therapy increased the function and percentage of CD8+ tumor-infiltrating lymphocytes, enhanced the functionality of CD8+ T cells within tumor-draining lymph nodes (TdLNs), and elevated the proportion of T central memory cells. Additionally, the combined treatments promoted the proportion of Migration Dendritic Cells type 1 (Mig DC1) within TdLNs, thereby enhancing their activation potential. Notably, FTY720-mediated blockade of lymphocyte egress abolished the therapeutic benefits, confirming TdLNs-dependent systemic immunity. Moreover, the efficacy of the combinational therapy depended on the migration of T cells from TdLNs to tumor site. In summary, we proposed a potentially effective combined treatment regimen and have elucidated the underlying cellular mechanisms that underpin its efficacy.

Local-region treatment comparison following conversion therapy of hepatocellular carcinoma: a period and age-dependent analysis

Background

Transarterial chemoembolization (TACE) is a potential conversion therapeutic strategy for unresectable hepatocellular carcinoma (uHCC). However, therapeutic options following conversion therapy are still controversial.

Objectives

This study aimed to compare the efficacy and safety of surgical resection (SR) and microwave ablation (MWA) after TACE conversion therapy for uHCC.

Design

A retrospective, multi-institutional study.

Methods

From June 2008 to October 2022, 8842 consecutive uHCC patients underwent initial TACE at 15 hospitals were identified. Among them, 1348 eligible patients who received TACE conversion therapy were included. The propensity score matching (PSM) was applied to reduce selection bias. To explore the effect of age on conversion therapy, a therapeutic factor analysis with age change was performed. The overall survival (OS) and disease-free survival (DFS) were compared using the Kaplan-Meier method with the log-rank test.

Results

After PSM 1:1, 542 patients in the MWA group were matched with those in the SR group. SR demonstrated better long-term survival outcomes (median OS, 10.6 vs 5.8 years, HR:1.83, 95% CI: 1.48-2.25, p < 0.001 and median DFS, 3.2 vs 2.5 years, HR: 1.27, 95% CI:1.09-1.49, p = 0.003) than MWA. There was an improvement in the 5-year DFS rate for MWA from 17.1% during 2009-2016 to 37.3% during 2017-2022, becoming comparable to the 40.8% of SR (p = 0.129). When the uHCC patients downstage met Milan criteria, the long-term OS and DFS were comparable between two groups (both, p > 0.05). SR presents an OS advantage over MWA at the age (years) of 45-54 (p = 0.036), 55-65 (p = 0.001), and >65 (p < 0.001), except <45(p = 0.140).

Conclusion

MWA might be acceptable as an alternative to SR in first-line therapeutic scheme after TACE conversion therapy for uHCC, especially, for the aged <45 years cohorts.

Preclinical study of TLR stimulation combined PD-1 antibody enhance the therapeutic effect of microwave ablation on NSCLC

PURPOSE

The purpose of this study was to investigate the therapeutic efficacy of the combination of microwave ablation (MWA) with immune checkpoints blockade and TLR9 stimulation in the treatment of non-small cell lung cancer (NSCLC) using the C57BL/6 tumor-bearing mice model.

MATERIALS AND METHODS

Tumor-bearing mice were treated with MWA, programmed cell death protein1 blockade (PD-1) plus MWA (MWA + P), TLR9 agonist CpG ODNs and MWA (MWA + C), PD-1 blockade and CpG ODNs (P + C), MWA plus PD-1 blockade and CpG ODNs (MWA + P + C), or untreated. Survival time was evaluated with the Kaplan-Meyer method comparing survival curves by log-rank test. On day 15 after MWA, ten mice from the combination therapy group received tumor rechallenge with LLC cells and the volumes of rechallenge tumor were calculated every 5 days. Immune cells were identified by immunohistochemistry and flow cytometry, and the concentrations of IFN-γ、TNF-α and TGF-β were identified by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The MWA + P + C combination therapy significantly prolonged tumor-bearing mice survival and reduced tumor size compared to untreated group, MWA group, MWA + P group, M + C group, P + C group. The combination therapy also protected most surviving mice from LLC tumor rechallenge. CD8 + T-cell in tumor and spleen were remarkably induced by MWA + P + C and Treg cell further diminished by combination therapy. Both tumor necrosis factor-alpha (TNF-α) and interferon-gama (IFN-γ) concentrations in plasma were significantly elevated in the combination therapy group compared to other groups, while transforming growth factor Beta (TGF-β) was reduced.

CONCLUSION

MWA combined with immune checkpoints blockade and TLR stimulation could significantly enhance antitumor efficacy with augmented specific immune responses, and the combination therapy is a promising approach to treat non-small cell lung cancer (NSCLC).

Inhibition of CTLA-4 accelerates atherosclerosis in hyperlipidemic mice by modulating the Th1/Th2 balance via the NF-κB signaling pathway

Objective

Though an increased risk of atherosclerosis is associated with anti-CTLA-4 antibody therapy, the underlying mechanisms remain unclear.

Methods

C57BL/6 mice were treated with anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibody twice a week for 4 weeks, after being injected with AAV8-PCSK9 and fed a Paigen diet (PD). The proportion of aortic plaque and lipid accumulation were assessed using Oil Red O staining, while the morphology of atherosclerotic lesions was analyzed with hematoxylin and eosin staining. Collagen content was evaluated through Picrosirius Red (PSR) staining, while inflammatory cell infiltration was examined with immunofluorescence staining. CD4+ T cells secreting IFN-γ and IL-4, which represent Th1 and Th2 cells respectively, were detected by flow cytometry and real-time PCR. Protein levels of p-IκBα, IκBα, p-p65, and p65 were determined by Western blot.

Results

Inhibiting CTLA-4 exacerbated PD-induced plaque progression and promoted CD4+ T cell infiltration in the aortic root. The anti-CTLA-4 antibody promoted CD4+ T cell differentiation toward the Th1 type, as indicated by an increase in the Th1/Th2 ratio. Compared to the anti-IgG group, treatment with anti-CTLA-4 antibody significantly elevated the protein levels of p-IκBα and p-p65, as well as the mRNA levels of TNF-α, IL-6, ICAM-1, and VCAM-1. Inhibiting the NF-κB signaling pathway attenuated the overall pathological phenotype induced by the anti-CTLA-4 antibody treatment.

Conclusion

Anti-CTLA-4 treatment promotes the progression of atherosclerosis by activating NF-κB signaling and modulating the Th1/Th2 balance. Our results provide a rationale for preventing and/or treating atherosclerosis accelerated by anti-CTLA-4 antibody therapy in cancer patients.

Blocking CTLA-4 promotes pressure overload-induced heart failure via activating Th17 cells

Targeting cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) with specific antibody offers long-term benefits for cancer immunotherapy but can cause severe adverse effects in the heart. This study aimed to investigate the role of anti-CTLA-4 antibody in pressure overload-induced cardiac remodeling and dysfunction. Transverse aortic constriction (TAC) was used to induce cardiac hypertrophy and heart failure in mice. Two weeks after the TAC treatment, mice received anti-CTLA-4 antibody injection twice a week at a dose of 10 mg/kg body weight. The administration of anti-CTLA-4 antibody exacerbated TAC-induced decline in cardiac function, intensifying myocardial hypertrophy and fibrosis. Further investigation revealed that anti-CTLA-4 antibody significantly elevated systemic inflammatory factors levels and facilitated the differentiation of T helper 17 (Th17) cells in the peripheral blood of TAC-treated mice. Importantly, anti-CTLA-4 mediated differentiation of Th17 cells and hypertrophic phenotype in TAC mice were dramatically alleviated by the inhibition of interleukin-17A (IL-17A) by an anti-IL-17A antibody. Furthermore, the C-X-C motif chemokine receptor 4 (CXCR4) antagonist AMD3100, also reversed anti-CTLA-4-mediated cardiotoxicity in TAC mice. Overall, these results suggest that the administration of anti-CTLA-4 antibody exacerbates pressure overload-induced heart failure by activating and promoting the differentiation of Th17 cells. Targeting the CXCR4/Th17/IL-17A axis could be a potential therapeutic strategy for mitigating immune checkpoint inhibitors-induced cardiotoxicity.

Immunomodulatory effects of microwave ablation on malignant tumors

Image-guided thermal ablation (IGTA) is an important treatment modality for interventional oncology. It is widely used for the treatment of solid tumors, such as liver, lung, breast, kidney, and thyroid cancers. IGTA include radiofrequency ablation, microwave ablation (MWA), cryoablation, and laser ablation. Compared with other energy sources, MWA has the advantage of a large ablative volume, short ablative time, and a low heat sink effect. MWA can also induce antitumor immunity; however, only a minority of patients derive a clinical benefit from it. Based on these data, the combination of MWA and immunotherapy has emerged as a promising new direction for cancer treatment. This review article focuses on current research on the combination of MWA and immunotherapy. The status of immune activation and related studies involving MWA for the treatment of various malignant tumors are discussed.

Immunostimulatory effects of thermal ablation: Challenges and future prospects

ABSTRACT

This literature explores the immunostimulatory effects of thermal ablation in the tumor microenvironment, elucidating the mechanisms such as immunogenic cell death, tumor-specific antigens, and damage-associated molecular patterns. Furthermore, it outlines critical issues associated with thermal ablation-induced immunostimulatory challenges and offers insights into future research avenues and potential therapeutic strategies.

Synergizing Thermal Ablation Modalities with Immunotherapy: Enough to Induce Systemic Antitumoral Immunity?

Thermal ablation modalities (cryoablation, radiofrequency ablation, and microwave ablation) have long been noted to occasionally induce a systemic antitumoral response. With the widespread use of checkpoint inhibitors, there is a significant interest in whether thermal ablation can promote immune system tumor recognition and increase checkpoint inhibitor response rates. In this review, we examine the current state of preclinical and clinical evidence examining the combination of checkpoint inhibitor therapies and thermal ablation modalities as well as discuss remaining the unanswered questions and directions for future research.

Inducing the Abscopal Effect in Liver Cancer Treatment: The Impact of Microwave Ablation Power Levels and PD-1 Antibody Therapy

Microwave ablation (MWA) is an effective treatment for liver cancer (LC), but its impact on distant tumors remains to be fully elucidated. This study investigated the abscopal effects triggered by MWA treatment of LC, at different power levels and with or without combined immune checkpoint inhibition (ICI). We established a mouse model with bilateral subcutaneous LC and applied MWA of varied power levels to ablate the right-sided tumor, with or without immunotherapy. Left-sided tumor growth was monitored to assess the abscopal effect. Immune cell infiltration and distant tumor neovascularization were quantified via immunohistochemistry, revealing insights into the tumor microenvironment and neovascularization status. Th1- and Th2-type cytokine concentrations in peripheral blood were measured using ELISA to evaluate systemic immunological changes. It was found that MWA alone, especially at lower power, promoted distant tumor growth. On the contrary, combining high-power MWA with anti-programmed death (PD)-1 therapy promoted CD8+ T-cell infiltration, reduced regulatory T-cell infiltration, upregulated a Th1-type cytokine (TNF-α) in peripheral blood, and inhibited distant tumor growth. In summary, combining high-power MWA with ICI significantly enhances systemic antitumor immune responses and activates the abscopal effect, offering a facile and robust strategy for improving treatment outcomes.