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BackgroundThe characteristics of the tumor immunosuppressive microenvironment represent a major challenge that limits the efficacy of immunotherapy. Our previous results suggested that cryo-thermal therapy, a tumor ablation system developed in our laboratory, promotes macrophage M1-type polarization and the complete maturation of DCs to remodel the immunosuppressive environment. However, the cells that respond promptly to CTT have not yet been identified. CTT can cause extensive cell death and the release of danger-associated molecular patterns and antigens. Neutrophils are the first white blood cells recruited to sites of damage and acute inflammation. Therefore, we hypothesized that neutrophils are the initial cells that respond to CTT and are involved in the subsequent establishment of antitumor immunity.MethodsIn this study, we examined the kinetics of neutrophil recruitment after CTT via flow cytometry and immunofluorescence staining and explored the effect of neutrophils on the establishment of systemic antitumor immunity by in vivo neutrophil depletion and in vitro co-culture assays.ResultsWe found that CTT led to a rapid and strong proinflammatory neutrophil response, which was essential for the long-term survival of mice. CTT-induced neutrophils promoted the activation of monocytes via reactive oxygen species and further upregulated the expression of IFN-γ and cytotoxic molecules in T and NK cells. Adoptive neutrophil transfer further enhanced the antitumor efficacy of CTT in tumor models of spontaneous and experimental metastasis.ConclusionThese results reveal the important role of neutrophil‒monocyte interactions in the development of anti-tumor immunity and highlight that CTT could be used as an immunotherapy for targeting neutrophils and monocytes to enhance antitumor immunity.

IntroductionRecently, 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.MethodsTo 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.ResultsIFNγ 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.DiscussionOur 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.

The Environmental Lapse Rate (ELR) depicts how the temperature near the surface varies with altitude and can be used for temperature downscaling coarse resolution data and for understanding boundary layer processes. We calculated the ELR using ERA5 reanalysis data, examined its temporal and larger-scale spatial variability, and found a prevalent seasonal ELR cycle over the Arctic. There are extensive positive ELR values resulting from pervasive inversions over most of the Arctic in winter; hence, we also explored the possible factors that lead to inversions in polar regions. Our results can serve as a reference for future research on the inversions in different morphological regions at different pressure levels. By improving the characterization of the ELR, we obtain a more explicit representation of the vertical temperature variation across the Arctic region and examine potential trends in ELR over time. Our results challenge the commonly assumed fixed ELR values that are typically used in the Arctic region in, for example, correcting ice-core temperature reconstructions or estimating higher-resolution runoff from land ice.

Background Myeloid‐derived suppressor cells (MDSCs) can potently inhibit T-cell activity, promote growth and metastasis of tumor and contribute to resistance to immunotherapy. Targeting MDSCs to alleviate their protumor functions and immunosuppressive activities is intimately associated with cancer immunotherapy. Natural killer (NK) cells can engage in crosstalk with multiple myeloid cells to alter adaptive immune responses, triggering T-cell immunity. However, whether the NK-cell-MDSC interaction can modulate the T-cell immune response requires further study. Cryo-thermal therapy could induce the maturation of MDSCs by creating an acute inflammatory environment to elicit a CD4+ Th1-dominant immune response, but the mechanism regulating this process remains unclear.Methods NK cells were depleted and NKG2D was blocked with monoclonal antibodies in vivo. MDSCs, NK cells and T cells were assessed by flow cytometry and isolated by magnetic-activated cell sorting (MACS). MDSCs and NK cells were cocultured with T cells to determine their immunological function. The transcriptional profiles of MDSCs were measured by qRT-PCR and RNA-sequencing. Isolated NK cells and MDSCs by MACS were cocultured to study the viability and maturation of MDSCs regulated by NK cells. TIMER was used to comprehensively examine the immunological, clinical, and genomic features of tumors.Results NK-cell activation after cryo-thermal therapy decreased MDSC accumulation and reprogrammed immunosuppressive MDSCs toward a mature phenotype to promote T cell antitumor immunity. Furthermore, we discovered that NK cells could kill MDSCs via the NKG2D-NKG2DL axis and promote MDSC maturation by interferon gamma (IFN-γ) in response to NKG2D. In addition, CD4+ Th1-dominant antitumor immune response was dependent on NKG2D, which promoted the major histocompatibility complex Ⅱ pathway of MDSCs. High activated NK-cell infiltration and NKG2D level in tumors were positively correlated with better clinical outcomes.Conclusions Cryo-thermal therapy induces effective CD4+ Th1-dominant antitumor immunity by activating NK cells to reprogram MDSCs, providing a promising therapeutic strategy for cancer immunotherapy.

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.

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 therapymediated 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 longlasting 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. [ABSTRACT FROM AUTHOR]