A Novel Multi-Mode Thermal Therapy for Colorectal Cancer Liver Metastasis: A Pilot Study

Immune dynamics shaping pre-metastatic and metastatic niches in liver metastases: from molecular mechanisms to therapeutic strategies

Liver metastases are commonly detected in the advanced stages of various malignant tumors, representing a significant clinical challenge. Throughout the process of liver metastases formation, immune cells play a pivotal role, particularly in the pre-metastatic and metastatic niches within the liver. Immune cells establish extensive and intricate interactions with tumor cells and other components in the liver, collectively promoting and sustaining the growth of liver metastases. Despite the limited efficacy of existing therapeutic modalities against some advanced liver metastases, novel immune-based treatment approaches are continuously being explored and validated. Building on the systematic elucidation of the immunosuppressive characteristics of liver metastases, we explored the potential of novel immunotherapies applicable to patients with liver metastases from multiple dimensions.

IFNγ at the early stage induced after cryo-thermal therapy maintains CD4+ Th1-prone differentiation, leading to long-term antitumor immunity

Introduction

Recently, more and more research illustrated the importance of inducing CD4+ T helper type (Th)-1 dominant immunity for the success of tumor immunotherapy. Our prior studies revealed the crucial role of CD4+ Th1 cells in orchestrating systemic and durable antitumor immunity, which contributes to the satisfactory outcomes of the novel cryo-thermal therapy in the B16F10 tumor model. However, the mechanism for maintaining the cryo-thermal therapy-mediated durable CD4+ Th1-dominant response remains uncovered. Additionally, cryo-thermal-induced early-stage CD4+ Th1-dominant T cell response showed a correlation with the favorable prognosis in patients with colorectal cancer liver metastasis (CRCLM). We hypothesized that CD4+ Th1-dominant differentiation induced during the early stage post cryo-thermal therapy would affect the balance of CD4+ subsets at the late phase.

Methods

To understand the role of interferon (IFN)-γ, the major effector of Th1 subsets, in maintaining long-term CD4+ Th1-prone polarization, B16F10 melanoma model was established in this study and a monoclonal antibody was used at the early stage post cryo-thermal therapy for interferon (IFN)-γ signaling blockade, and the influence on the phenotypic and functional change of immune cells was evaluated.

Results

IFNγ at the early stage after cryo-thermal therapy maintained long-lasting CD4+ Th1-prone immunity by directly controlling Th17, Tfh, and Tregs polarization, leading to the hyperactivation of Myeloid-derived suppressor cells (MDSCs) represented by abundant interleukin (IL)-1β generation, and thereby further amplifying Th1 response.

Discussion

Our finding emphasized the key role of early-phase IFNγ abundance post cryo-thermal therapy, which could be a biomarker for better prognosis after cryo-thermal therapy.

Survival Analysis for Multimode Ablation Using Self-Adapted Deep Learning Network Based on Multisource Features

Novel multimode thermal therapy by freezing before radio-frequency heating has achieved a desirable therapeutic effect in liver cancer. Compared with surgical resection, ablation treatment has a relatively high risk of tumor recurrence. To monitor tumor progression after ablation, we developed a novel survival analysis framework for survival prediction and efficacy assessment. We extracted preoperative and postoperative MRI radiomics features and vision transformer-based deep learning features. We also combined the immune features extracted from peripheral blood immune responses using flow cytometry and routine blood tests before and after treatment. We selected features using random survival forest and improved the deep Cox mixture (DCM) for survival analysis. To properly accommodate multitype input features, we proposed a self-adapted fully connected layer for locally and globally representing features. We evaluated the method using our clinical dataset. Of note, the immune features rank the highest feature importance and contribute significantly to the prediction accuracy. The results showed a promising C$^{\mathit{td}}$-index of 0.885 $\pm$ 0.040 and an integrated Brier score of 0.041 $\pm$ 0.014, which outperformed state-of-the-art method combinations of survival prediction. For each patient, individual survival probability was accurately predicted over time, which provided clinicians with trustable prognosis suggestions.

Exploration of the impact of multimode thermal therapy versus radiofrequency ablation on CD8+ T effector cells of liver malignancies based on single cell transcriptomics

Introduction

Multimode thermal therapy (MTT) is an innovative interventional therapy developed for the treatment of liver malignancies. When compared to the conventional radiofrequency ablation (RFA), MTT typically offers improved prognosis for patients. However, the effect of MTT on the peripheral immune environment and the mechanisms underlying the enhanced prognosis have yet to be explored. The aim of this study was to further investigate the mechanisms responsible for the difference in prognosis between the two therapies.

Methods

In this study, peripheral blood samples were collected from four patients treated with MTT and two patients treated with RFA for liver malignancies at different time points before and after the treatment. Single cell sequencing was performed on the blood samples to compare and analyze the activation pathways of peripheral immune cells following the MTT and RFA treatment.

Results

There was no significant effect of either therapy on the composition of immune cells in peripheral blood. However, the differential gene expression and pathway enrichment analysis demonstrated enhanced activation of T cells in the MTT group compared to the RFA group. In particular, there was a remarkable increase in TNF-α signaling via NF-κB, as well as the expression of IFN-α and IFN-γ in the CD8⁺ effector T (CD8⁺ Teff) cells subpopulation, when compared to the RFA group. This may be related to the upregulation of PI3KR1 expression after MTT, which promotes the activation of PI3K-AKT-mTOR pathway.

Conclusion

This study confirmed that MTT could more effectively activate peripheral CD8⁺ Teff cells in patients compared with RFA and promote the effector function, thus resulting in a better prognosis. These results provide a theoretical basis for the clinical application of MTT therapy.

Combining all-trans retinoid acid treatment targeting myeloid-derived suppressive cells with cryo-thermal therapy enhances antitumor immunity in breast cancer

Targeting myeloid-derived suppressive cells (MDSCs) has been considered a potential strategy in tumor therapy. However, a single drug targeting MDSCs remains a challenge in the clinic. An increasing number of studies have shown that combination agents targeting MDSCs and immunotherapy may provide exciting new insights and avenues to explore in tumor therapy. In our previous study, a novel cryo-thermal therapy was developed for metastatic tumors that systematically activate innate and adaptive immunity. Moreover, cryo-thermal therapy was shown to dramatically decrease the levels of MDSCs and induce their differentiation toward potent antigen-presenting cells. However, the therapeutic effects of cryo-thermal therapy on the 4T1 mouse breast cancer model were still not satisfactory because of the high level of MDSCs before and after treatment. Therefore, in this study, we combined cryo-thermal therapy with all-trans retinoid acid (ATRA), a small molecule drug that can induce the inflammatory differentiation of MDSCs. We found that combination therapy notably upregulated the long-term survival rate of mice. Mechanically, combination therapy promoted the phenotype and functional maturation of MDSCs, efficiently decreasing suppressive molecule expression and inhibiting glutamine and fatty acid metabolism. Moreover, MDSCs at an early stage after combination therapy significantly decreased the proportions of Th2 and Treg subsets, which eventually resulted in Th1-dominant CD4⁺ T-cell differentiation, as well as enhanced cytotoxicity of CD8⁺ T cells and natural killer cells at the late stage. This study suggests a potential therapeutic strategy for combination ATRA treatment targeting MDSCs with cryo-thermal therapy to overcome the resistance of MDSC-induced immunosuppression in the clinic.

Th1-Dominant CD4+ T Cells Orchestrate Endogenous Systematic Antitumor Immune Memory After Cryo-Thermal Therapy

Recent studies suggest that highly activated, polyfunctional CD4⁺ T cells are incredibly effective in strengthening and sustaining overall host antitumor immunity, promoting tumor-specific CD4⁺ T-cell responses and effectively enhancing antitumor immunity by immunotherapy. Previously, we developed a novel cryo-thermal therapy for local tumor ablation and achieved long-term survival rates in several tumor models. It was discovered that cryo-thermal therapy remodeled the tumor microenvironment and induced an antigen-specific CD4⁺ T-cell response, which mediated stronger antitumor immunity in vivo. In this study, the phenotype of bulk T cells in spleen was analyzed by flow cytometry after cryo-thermal therapy and both CD4⁺ Th1 and CD8⁺ CTL were activated. In addition, by using T-cell depletion, isolation, and adoptive T-cell therapy, it was found that cryo-thermal therapy induced Th1-dominant CD4⁺ T cells that directly inhibited the growth of tumor cells, promoted the maturation of MDSCs via CD4⁺ T-cell-derived IFN-γ and enhanced the cytotoxic effector function of NK cells and CD8⁺ T cells, and promoted the maturation of APCs via cell-cell contact and CD4⁺ T-cell-derived IFN-γ. Considering the multiple roles of cryo-thermal-induced Th1-dominant CD4⁺ T cells in augmenting antitumor immune memory, we suggest that local cryo-thermal therapy is an attractive thermo-immunotherapy strategy to harness host antitumor immunity and has great potential for clinical application.

Complications Risk Assessment and Imaging Findings of Thermal Ablation Treatment in Liver Cancers: What the Radiologist Should Expect

One of the major fields of application of ablation treatment is liver tumors. With respect to HCC, ablation treatments are considered as upfront treatments in patients with early-stage disease, while in colorectal liver metastases (CLM), they can be employed as an upfront treatment or in association with surgical resection. The main prognostic feature of ablation is the tumor size, since the goal of the treatment is the necrosis of all viable tumor tissue with an adequate tumor-free margin. Radiofrequency ablation (RFA) and microwave ablation (MWA) are the most employed ablation techniques. Ablation therapies in HCC and liver metastases have presented a challenge to radiologists, who need to assess response to determine complication-related treatment. Complications, defined as any unexpected variation from a procedural course, and adverse events, defined as any actual or potential injury related to the treatment, could occur either during the procedure or afterwards. To date, RFA and MWA have shown no statistically significant differences in mortality rates or major or minor complications. To reduce the rate of major complications, patient selection and risk assessment are essential. To determine the right cost-benefit ratio for the ablation method to be used, it is necessary to identify patients at high risk of infections, coagulation disorders and previous abdominal surgery interventions. Based on risk assessment, during the procedure as part of surveillance, the radiologists should pay attention to several complications, such as vascular, biliary, mechanical and infectious. Multiphase CT is an imaging tool chosen in emergency settings. The radiologist should report technical success, treatment efficacy, and complications. The complications should be assessed according to well-defined classification systems, and these complications should be categorized consistently according to severity and time of occurrence.