Nanosecond pulsed electric field stimulates CD103+ DC accumulation in tumor microenvironment via NK-CD103+ DC crosstalk.

CD103+ DC is crucial for antitumor immune response. As a promising local therapy on cancers, nanosecond pulsed electric field (nsPEF) has been widely reported to stimulate anti-tumor immune response, but the underlying relationship between intratumoral CD103+ DC and nsPEF treatment remains enigmatic. Here, we focused on the behavior of CD103+ DC in response to nsPEF treatment and explored the underlying mechanism. We found that the nsPEF treatment led to the activation and accumulation of CD103+ DC in tumor. Depletion of CD103+ DC via Batf3-/- mice demonstrated CD103+ DC was necessary for intratumoral CD8+ T cell infiltration and activation in response to nsPEF treatment. Notably, NK cells recruited CD103+ DC into nsPEF-treated tumor through CCL5. Inflammatory array revealed CD103+ DC-derived IL-12 mediated the CCL5 secretion in NK cells. In addition, the boosted activation and infiltration of intratumoral CD103+ DC were abolished by cGAS-STING pathway inhibition, following IL-12 and CCL5 decreasing. Furthermore, nsPEF treatment promoting CD103+ DC-mediated antitumor response enhanced the effects of CD47 blockade strategy. Together, this study uncovers an unprecedented role for CD103+ DC in nsPEF treatment-elicited antitumor immune response and elucidates the underlying mechanisms.

Nanosecond Pulsed Electric Field Induces an Antitumor Effect in Triple-Negative Breast Cancer via CXCL9 Axis Dependence in Mice.

Triple-negative breast cancer (TNBC) is a refractory tumor, and therapeutic options are very limited. Local ablation has been applied recently. Chemokines play a critical role in the recruitment of immune cells into ablative tumors. Nanosecond pulsed electric field (nsPEF) shows potential anti-tumor efficacy, but the mechanism for maintaining the immune effect is not very clear. Here, we applied nsPEF for treating 4T1 breast cancer cells in vitro. RNA sequencing (RNA-seq) was applied. Anti-CXCL9 was used alone or combined with nsPEF to treat triple-negative breast cancer in mice. We demonstrated that nsPEF effectively induced cell apoptosis and inhibited the growth and metastasis of triple-negative breast cancer. An immune effect, especially chemotaxis, was activated by nsPEF. The number of infiltrated CD8+ T cells was increased significantly. We found that the inhibition of residual breast cancer growth by nsPEF was dependent on the CXCL9 axis. In conclusion, our work demonstrated that nsPEF effectively ablated the tumor, aroused an immune response, and inhibited residual breast cancer growth via CXCL9 axis dependence in mice.

Targeting neuropilin-1 abolishes anti-PD-1-upregulated regulatory T cells and synergizes with 4-1BB agonist for liver cancer treatment.

BACKGROUND AIMS: Regulatory T cells (Tregs) are an obstacle to PD-1 blockade-mediated antitumor efficacy. However, the behaviors of Tregs response to anti-PD-1 in HCC and the characteristics of Tregs tissue adaptation from peripheral lymphoid tissues to the tumor are still unclear. APPROACH RESULTS: Here, we determine that PD-1 monotherapy potentially augments the accumulation of tumor CD4 + Tregs. Mechanistically, anti-PD-1 mediates Tregs proliferation in lymphoid tissues rather than in the tumor. Increased peripheral Tregs burden replenishes intratumoral Tregs, raising the ratio of intratumoral CD4 + Tregs to CD8 + T cells. Subsequently, single-cell transcriptomics revealed that neuropilin-1 (Nrp-1) supports Tregs migration behavior, and the genes of Crem and Tnfrsf9 regulate the behaviors of the terminal suppressive Tregs. Nrp-1 + 4-1BB - Tregs stepwise develop to the Nrp-1 - 4-1BB + Tregs from lymphoid tissues into the tumor. Moreover, Treg-restricted Nrp1 depletion abolishes anti-PD-1-upregulated intratumoral Tregs burden and synergizes with the 4-1BB agonist to enhance the antitumor response. Finally, a combination of the Nrp-1 inhibitor and the 4-1BB agonist in humanized HCC models showed a favorable and safe outcome and evoked the antitumor effect of the PD-1 blockade. CONCLUSION: Our findings elucidate the potential mechanism of anti-PD-1-mediated intratumoral Tregs accumulation in HCC and uncover the tissue adaptation characteristics of Tregs and identify the therapeutic potential of targeting Nrp-1 and 4-1BB for reprogramming the HCC microenvironment.

Lenvatinib enhances antitumor immunity by promoting the infiltration of TCF1+ CD8+ T cells in HCC via blocking VEGFR2.

Lenvatinib is the favorable treatment for advanced hepatocellular carcinoma (HCC), and it is currently undergoing phase III clinical trials. However, the specific effects of lenvatinib on PD1+ CD8+ T cells in HCC microenvironment have not been systematically studied. Here, we established an orthotopic hepa1-6 mouse model treated with lenvatinib to investigate CD8+ T cells' role in the tumor and spleen. We found an increasing proportion of TCF-1+ in PD1+ CD8+ T cells and proliferation of PD1+ CD8+ T cells after lenvatinib treatment. Meanwhile, lenvatinib treatment upregulated the expression of granzyme B on PD1+ CD8+ T cells both in vitro and in vivo. Lenvatinib activated the endogenous mTOR pathway of exhausted CD8+ T cells, and mTOR pathway blockade eliminated the antitumor effect of lenvatinib and function of PD1+ CD8+ T cells. The effects of the mTOR pathway on PD1+ CD8+ T cells after lenvatinib treatment were mediated by VEGFR2 inhibition. Overall, our work provides insight into the mechanism of lenvatinib's antitumor efficacy through exhausted CD8+ T cells in HCC treatment.

Disulfiram/Copper Induces Immunogenic Cell Death and Enhances CD47 Blockade in Hepatocellular Carcinoma.

Some chemotherapeutic agents have been found to enhance antitumor immunity by inducing immunogenic cell death (ICD). The combination of disulfiram (DSF) and copper (Cu) has demonstrated anti-tumor effects in a range of malignancies including hepatocellular carcinoma (HCC). However, the potential of DSF/Cu as an ICD inducer and whether it can enhance the efficacy of the immune checkpoint blockade in HCC remains unknown. Here, we showed that DSF/Cu-treated HCC cells exhibited characteristics of ICD in vitro, such as calreticulin (CRT) exposure, ATP secretion, and high mobility group box 1 (HMGB1) release. DSF/Cu-treated HCC cells elicited significant immune memory in a vaccination assay. DSF/Cu treatment promoted dendritic cell activation and maturation. The combination of DSF/Cu and CD47 blockade further facilitated DC maturation and subsequently enhanced CD8+ T cell cytotoxicity. Mechanically, DSF/Cu promoted the nuclear accumulation and aggregation of nuclear protein localization protein 4 (NPL4) to inhibit the ubiquitin-proteasome system; thus, inducing endoplasmic reticulum (ER) stress. The inhibition of NPL4 induced ICD-associated damage-associated molecular patterns. Collectively, our findings demonstrated that DSF/Cu-induced ICD-mediated immune activation in HCC enhanced the efficacy of CD47 blockade.

Combination with Toll-like receptor 4 (TLR4) agonist reverses GITR agonism mediated M2 polarization of macrophage in Hepatocellular carcinoma.

The glucocorticoid-induced tumor necrosis factor receptor (GITR) agonistic antibody (DTA-1) has been proved to elicit robust immune response in various kinds of tumors. However, only a few of the HCC patients could benefit from it, and the mechanism of DTA-1 resistance remains unknown. Here, we measured GITR expression in different immunocytes in HCC microenvironment, and we observed that tumor-infiltrating regulatory T cells (Ti-Tregs) significantly expressed GITR, which were associated with poor prognosis. Meanwhile, we analyzed the variation of tumor-infiltrating immune components and associated inflammation response after DTA-1 treatment in orthotopic liver cancer model of mice. Surprisingly, DTA-1 treatment reduced the infiltration of Tregs but failed to activate CD8+ T cells and elicit antitumor efficacy. In particular, DTA-1 treatment enforced alternative M2 polarization of macrophage, and macrophage depletion could enhance DTA-1-mediated antitumor efficacy in HCC. Mechanistically, macrophage M2 polarization attributed to the IL-4 elevation induced by Th2 immune activation in the treatment of DTA-1, resulting in DTA-1 resistance. Furthermore, Toll-like receptor 4 (TLR4) agonist could diminish the macrophage (M2) polarization and reverse the M2-mediated DTA-1 resistance, eliciting robust antitumor effect in HCC. Our finding demonstrated that the TLR4 agonist synergized with DTA-1 was a potential strategy for HCC treatment.

Blocking CD47 promotes antitumour immunity through CD103+ dendritic cell-NK cell axis in murine hepatocellular carcinoma model.

BACKGROUND & AIMS: The CD47-signal regulatory protein α (SIRPα) axis inhibits dendritic cell (DC) phagocytosis and contributes to immune evasion. However, the behaviour of DCs and the potential crosstalk between DCs and natural killer (NK) cells in the hepatocellular carcinoma (HCC) microenvironment after CD47 blockade remain unclear. METHODS: The infiltration of CD103+ DCs and NK cells were analysed by immunohistochemistry and immunofluorescence in both human and murine HCC specimens. An orthotopic liver tumour model was used to evaluate the function of the CD103+ DC-NK cell axis after CD47 blockade in vivo in wild-type, Rag1-/-, Batf3-/-, and STING1-/- mice. Phagocytosis assays were performed in CD103+ DC and HCC cell lines. CD103+ DC-derived cytokines were analysed by chemokine array. Spleen-derived NK cells in C57BL/6J mice were used to evaluate cytotoxic functions in vitro. RESULTS: Higher CD47 expression was associated with worse prognosis in patients with HCC. CD47 blockade enhanced antitumour efficacy by stimulating the CD103+ DC-NK cell axis. The hypoxic microenvironment promoted CD47 blockade-induced tumour DNA phagocytosis by CD103+ DCs. By releasing IL-12 and CXCL9, activated CD103+ DCs induced the recruitment of NK cells with upregulated expression of granzyme B, NKG2D, interferon-γ, and tumour necrosis factor-α and downregulated expression of NKG2A. The antitumour effects of CD47 blockade could be abolished by cyclic GMP-AMP synthase (cGAS)-STING pathway inhibition. CONCLUSIONS: In addition to the classical DC-T cell axis, CD47 blockade significantly enhanced the ability of CD103+ DCs to take up tumour DNA, resulting in the stimulation of the cGAS-STING pathway, which promoted the infiltration and activation of NK cells in liver cancer. LAY SUMMARY: Hypoxia (low oxygen levels) is prevalent in the hepatocellular carcinoma microenvironment and promotes the phagocytosis (ingestion and elimination) of tumour DNA by CD103+ dendritic cells (a type of immune cell). Blockade of the cell surface protein CD47 resulted in activation of CD103+ dendritic cells which led to the recruitment and activation of natural killer cells (a different immune cell). When activated, these cells exhibit an antitumour effect.

Self-assembly nanovaccine containing TLR7/8 agonist and STAT3 inhibitor enhances tumor immunotherapy by augmenting tumor-specific immune response.

BACKGROUND: Cancer vaccines are a promising strategy for cancer immunotherapy. Cancer vaccines elicits a specific cytotoxic immune response to tumor antigens. However, the efficacy of traditional peptide-based cancer vaccines is limited due to the inefficient delivery of antigens and adjuvants to dendritic cells (DCs). Therefore, it is necessary to develop a novel rationally designed cancer vaccine to maximize its desired effects. METHODS: A Self-assembling Vehicle-free Multi-component Antitumor nanoVaccine (SVMAV) was constructed by using an unsaturated fatty acid docosahexaenoic acid (DHA)-conjugated antigen and R848 (a Toll-like receptor 7/8 agonist) to encapsulate stattic (a signal transducer and activator of transcription 3 inhibitor). The characteristics of SVMAV were investigated. The ability of SVMAV to promote DC functions was examined by in vitro analysis. The antitumor effects of SVMAV and its combination with antiprogrammed cell death protein 1 antibody (aPD-1) were also investigated in vivo. The potential application of SVMAV for neoantigen-targeted, personalized cancer vaccines was examined in an orthotopic hepatocellular carcinoma model. RESULTS: The obtained SVMAV efficiently migrated into lymph nodes and primed CD8+ T cells for exert neoantigen-specific killing by promoting the antigen uptake by DCs, stimulating DC maturation, and enhancing antigen cross-presentation, due to the simultaneous delivery of the antigen, R848 and stattic. SVMAV could not only yield a robust antitumor effect for primary melanoma allografts, but also exert a protective effect for lung metastases. Moreover, combination treatment of SVMAV and aPD-1 exerted synergistic antitumor activity and extended the survival duration of melanoma-bearing mice. Notably, a cell line-specific neoantigen-based SVMAV was designed according to predicted neoantigens for Hepa1-6 cells to examine the potential application of SVMAV for personalized cancer vaccine. Encouragingly, neoantigen-specific SVMAV achieved stronger antitumor activity than aPD-1 in an orthotopic hepatocellular cancer model established with Hepa1-6 cells. CONCLUSIONS: In summary, this study offers an efficient codelivery platform for neoantigens and immunoregulatory compounds to enhance immune responses during cancer immune therapy.

Tumor Immune Microenvironment Characterization in Hepatocellular Carcinoma Identifies Four Prognostic and Immunotherapeutically Relevant Subclasses.

PURPOSE: The tumor microenvironment (TME) plays a critical role in the pathogenesis of hepatocellular carcinoma (HCC). However, underlying compositions and functions that drive the establishment and maintenance of the TME classifications are less-well understood. METHODS: A total of 766 HCC patients from three public cohorts were clustered into four immune-related subclasses based on 13 TME signatures (11 immune-related cells and 2 immune-related pathways) calculated by MCP-counter. After analyzing the landscapes of functional annotation, methylation, somatic mutation, and clinical characteristics, we built a TME-based Support Vector Machine of 365 patients (discovery phase) and 401 patients (validation phase). We applied this SVM model on another two independent cohorts of patients who received sorafenib/pembrolizumab treatment. RESULTS: About 33% of patients displayed an immune desert pattern. The other subclasses were different in abundance of tumor infiltrating cells. The Immunogenic subclass (17%) associated with the best prognosis presented a massive T cell infiltration and an activation of immune checkpoint pathway. The 13 TME signatures showed a good potential to predict the TME classification (average AUC = 88%). Molecular characteristics of immunohistochemistry from Zhejiang cohort supported our SVM classification. The optimum response to pembrolizumab (78%) and sorafenib (81%) was observed in patients belonging to the Immunogenic subclass. CONCLUSIONS: The HCC patients from distinct immune subclass showed significant differences in clinical prognosis and response to personalized treatment. Based on tumor transcriptome data, our workflow can help to predict the clinical outcomes and to find appropriate treatment strategies for HCC patients.