Immune Checkpoint Blockade Research Articles

Tumor targeting peptide TMTP1 modified Antigen capture Nano-vaccine combined with chemotherapy and PD-L1 blockade effectively inhibits growth of ovarian cancer

The mortality of ovarian cancer (OC) has long been the highest among gynecological malignancies. Although OC is considered to be an immunogenic tumor, the effect of immunotherapy is not satisfactory. The immunosuppressive microenvironment is one reason for this, and the absence of recognized effective antigens for vaccines is another. Chemotherapy, as one of the most commonly used treatment for OC, can produce chemotherapy-associated antigens (CAAs) during treatment and show the effect of in situ vaccine. Herein, we designed an antigen capture nano-vaccine NP-TP1@M-M with tumor targeting peptide TMTP1 and dendritic cell (DC) receptor mannose assembled on the surface and adjuvant monophosphoryl lipid A (MPLA) encapsulated in the core of poly (D, L-lactide-co-glycolide) (PLGA) nanoparticles. PLGA itself possessed the ability of antigen capture. TMTP1 was a tumor-homing peptide screened by our research team, which held extensive and excellent tumor targeting ability. After these modifications, NP-TP1@M-M could capture and enrich more tumor-specific antigens after chemotherapy, stimulate DC maturation, activate the adaptive immunity and combined with immune checkpoint blockade to maximize the release of the body’s immune potential, providing an eutherapeutic strategy for the treatment of OC.

Nanoscale Metal-Organic Layer Reprograms Cellular Metabolism to Enhance Photodynamic Therapy and Antitumor Immunity.

Abnormal cancer metabolism causes hypoxic and immunosuppressive tumor microenvironment (TME), which limits the antitumor efficacy of photodynamic therapy (PDT). Herein, we report a photosensitizing nanoscale metal-organic layer (MOL) with anchored 3-bromopyruvate (BrP), BrP@MOL, as a metabolic reprogramming agent to enhance PDT and antitumor immunity. BrP@MOL inhibited mitochondrial respiration and glycolysis to oxygenate tumors and reduce lactate production. This metabolic reprogramming enhanced reactive oxygen species generation during PDT and reshaped the immunosuppressive TME to enhance antitumor immunity. BrP@MOL-mediated PDT inhibited tumor growth by >90 % with 40 % of mice being tumor-free, rejected tumor re-challenge, and prevented lung metastasis. Further combination with immune checkpoint blockade potently regressed the tumors with >98 % tumor inhibition and 80 % of mice being tumor-free.

Nanoscale Metal‐Organic Layer Reprograms Cellular Metabolism to Enhance Photodynamic Therapy and Antitumor Immunity

AbstractAbnormal cancer metabolism causes hypoxic and immunosuppressive tumor microenvironment (TME), which limits the antitumor efficacy of photodynamic therapy (PDT). Herein, we report a photosensitizing nanoscale metal–organic layer (MOL) with anchored 3‐bromopyruvate (BrP), BrP@MOL, as a metabolic reprogramming agent to enhance PDT and antitumor immunity. BrP@MOL inhibited mitochondrial respiration and glycolysis to oxygenate tumors and reduce lactate production. This metabolic reprogramming enhanced reactive oxygen species generation during PDT and reshaped the immunosuppressive TME to enhance antitumor immunity. BrP@MOL‐mediated PDT inhibited tumor growth by >90 % with 40 % of mice being tumor‐free, rejected tumor re‐challenge, and prevented lung metastasis. Further combination with immune checkpoint blockade potently regressed the tumors with >98 % tumor inhibition and 80 % of mice being tumor‐free.

Investigation of a tamoxifen-RACK7/KDM5C-IFN-I axis for ER+ breast cancer immunomodulation.

9 Background: ER+ breast cancer patients generally have good prognosis. However, significant relapse rates (i.e., hormone drugs, Tamoxifen/TMX) and the poor response to immune checkpoint blockade (ICB) remain critical issues to be addressed. Thus, exploration of anti-ICB resistant mechanisms and alternative targets is needed to improve therapeutic efficacy. Methods: To investigate potential cross-resistant mechanisms between hormone and ICB therapy, ER+ cell lines T47D and MCF7 cells were chronically-treated with TMX for 6 months, and subjected to RNA-Seq and pathway enrichment analysis. Dysregulation of identified factors were validated via western blotting, RT-qPCR, and flow cytometry. Target factors were then inhibited or depleted by shRNA knockdown (KD) or small-compound inhibition. Identified ICB resistance mechanisms were further elaborated by in vitro co-culture assays, syngeneic mouse models, and immune-profiling of tumor microenvironment (TME). Results: Chronic exposure to TMX activates Type I interferon (IFN-I) signaling, induces IFN I-stimulated gene (ISG) expression, and downregulates the H3K4 demethylase and ISG repressor complex known as RACK7/KDM5C. Chronic TMX also upregulates CEACAM1, a well-known ligand for the immune checkpoint receptor TIM3. Results prompt us to evaluate whether loss of RACK7 combined with TMX treatment may modulate a lymphocyte-attractive (via IFN-I), but T-cell exhaustive (via CEACAM1-TIM3) TME. Indeed, in vitro treatment of TMX under RACK7-KD conditions triggers STING upregulation, TBK1 hyperphosphorylation, and a more pronounced activation of ISGs and CEACAM1. In vivo, TMX combined with RACK7-KD enhances tumor growth in the TS/A (ER+) syngeneic mouse model, while immune-profiling reveal that this combination promotes lymphocyte infiltration with a higher population of terminally exhausted CD8+ T-cells in the TME. Conclusions: Our data demonstrate that the TMX-induced activation of cGAS/STING pathway and RACK7 downregulation coordinately shape the IFN-I and immune checkpoint signaling axes in ER+ breast cancer. This TMX–RACK7–IFN-I regulatory network promotes a lymphocyte-attractive TME via IFN-I signaling activation, whereas induction of inhibitory ligands renders T-cells to be terminally-exhausted and unable to kill tumors. These findings highlight the potential use of TMX’s STING-agonistic effect in re-shaping the “cold” breast cancer TME, and the use of combined TMX and anti-TIM3 or anti-CEACAM1 blockade to improve ICB therapy.

Prognostic and immunological significance of tertiary lymphoid structures in nasopharyngeal carcinoma.

220 Background: Tertiary lymphoid structures (TLSs) are ectopic lymphoid tissues found in non-lymphoid organs, characterized by the presence of CD20+ B cell follicles adjacent to a T cell zone. Their presence has been associated with improved survival in various tumor types. However, the role of TLSs in nasopharyngeal carcinoma (NPC) remains unclear. In this study, we investigated the prognostic and immunological significance of TLSs in NPC patients. Methods: The investigation involved a discovery cohort (n = 145) comprising NPC patients diagnosed at Sun Yat-sen University Cancer Center between July 2010 and December 2016, with pretreatment primary tumor samples collected. An independent validation cohort included 150 NPC patients with gene expression profiles, among whom Hematoxylin & Eosin (H&E)-stained slides were available for 95 patients. The primary endpoint of this study is overall survival, defined as the duration of time from diagnosis until death from any cause. The presence of TLSs was assessed on H&E and CD20-stained slides. Analyses of tumor-infiltrating immune cell subsets, differentially expressed genes, and BCR/TCR clonotypes were performed to explore the association between TLSs and the anti-tumor immune response. A molecular definition of TLSs was proposed and assessed for its prognostic value across multiple cohorts. Results: The presence of TLSs was independently associated with a favorable overall survival (hazard ratio [HR], 0.26; 95% confidence interval [CI], 0.07-0.94; log-rank p = 0.04), surpassing the significance of B cell density in multivariate analysis (HR, 0.83; 95% CI, 0.38-1.79, log-rank p = 0.63). These findings were corroborated in the independent validation cohort. TLSs positively correlated with multiple immune-related pathways and a higher proportion of functionally mature immune cells. Notably, the counts of BCR and TCR clonotypes showed a significant positive correlation with the TLSs score. We proposed a TLSs gene signature and demonstrated its prognostic relevance across multiple cohorts, including patients treated with immune checkpoint blockade. Conclusions: TLSs exhibit heightened immune activity and indicate improved survival outcomes in NPC patients. A TLSs gene signature was proposed and demonstrated its prognostic relevance across multiple cohorts, indicating potential guidance for treatment decisions in cancer.

Unsupervised clustering of brain tumor leukocytes to reveal atypical lymphoid cell subsets.

25 Background: The brain tumor immune microenvironment (TiME) is characterised by suppression of tumor-infiltrating leukocytes. The lymphocyte niche activity is particularly downregulated within this TiME milieu. Methods: Here, using data-driven approaches in flow cytometry and RNA sequencing analysis, we aimed at dissecting leukocyte cell types infiltrating human brain tumor TiME. Results: Unsupervised clustering provided T lymphocyte subsets including double-negative (CD3+CD4- CD8-) T cells (DNT). Our DNT phenotype was validated with an independent dataset, suggesting DNT to be compatible with γδ T cell phenotype. In our cohort, myeloid immune cell frequencies were associated with malignancy type as previously reported, while a gliosarcoma notably presented unexpectedly high lymphocyte frequencies. Consistently, double-positive (CD4+ CD8+) T cells (DPT) had higher frequency in the gliosarcoma than other tumors. The flow cytometry results were supported by transcriptome patterns and the activity of immune-related genes in these tumors. Conclusions: Our findings feature the benefit of data-driven approaches for brain TiME lymphocyte analysis, and show that primary brain tumors can entail atypical lymphocyte subsets like DNTs and DPT cells. Unbiased lymphocyte characterisation can potentially outline novel targets for immune checkpoint blockade therapy.

A Two-Pronged Nanostrategy of Iron Metabolism Disruption to Synergize Tumor Therapy by Triggering the Paraptosis-Apoptosis Hybrid Pathway.

Iron metabolism has emerged as a promising target for cancer therapy; however, the innate metabolic compensatory capacity of cancer cells significantly limits the effectiveness of iron metabolism therapy. Herein, bioactive gallium sulfide nanodots (GaSx), with dual functions of "reprogramming" and "interfering" iron metabolic pathways, were successfully developed for tumor iron metabolism therapy. The constructed GaSx nanodots ingeniously harness hydrogen sulfide (H2S) gas, which is released in response to the tumor microenvironment, to reprogram the inherent transferrin receptor 1 (TfR1)-ferroportin 1 (FPN1) iron metabolism axis in cancer cells. Concurrently, the gallium ions (Ga3+) derived from GaSx act as a biochemical "Trojan horse", mimicking the role of iron and displacing it from essential biomolecular binding sites, thereby influencing the fate of cancer cells. By leveraging the dual mechanisms of Ga3+-mediated iron disruption and H2S-facilitated reprogramming of iron metabolic pathways, GaSx prompted the initiation of a paraptosis-apoptosis hybrid pathway in cancer cells, leading to marked suppression of tumor proliferation. Importantly, the dysregulation of iron metabolism induced by GaSx notably increased tumor cell susceptibility to both chemotherapy and immune checkpoint blockade (ICB) therapy. This study underscores the therapeutic promise of gas-based interventions and metal ion interference strategies for the tumor metabolism treatment.

Tumor-associated macrophage clusters linked to immunotherapy in a pan-cancer census

Transcriptional heterogeneity of tumor-associated macrophages (TAMs) has been investigated in individual cancers, but the extent to which these states transcend tumor types and represent a general feature of cancer remains unclear. We performed pan-cancer single-cell RNA sequencing analysis across nine cancer types and identified distinct monocyte/TAM composition patterns. Using spatial analysis from clinical study tissues, we assessed TAM functions in shaping the tumor microenvironment (TME) and influencing immunotherapy. Two specific TAM clusters (pro-inflammatory and pro-tumor) and four TME subtypes showed distinct immunological features, genomic profiles, immunotherapy responses, and cancer prognosis. Pro-inflammatory TAMs resided in immune-enriched niches with exhausted CD8+ T cells, while pro-tumor TAMs were restricted to niches associated with a T-cell-excluded phenotype and hypoxia. We developed a machine learning model to predict immune checkpoint blockade response by integrating TAMs and clinical data. Our study comprehensively characterizes the common features of TAMs and highlights their interaction with the TME.

COX inhibition with anti-PD-1 in advanced dMMR colorectal cancer: Improving antigen presentation?

dMMR tumors, which have high tumor mutational and neoantigen burdens, are highly responsive to immune checkpoint blockade. Wu etal.1 showed that combining COX inhibitors with PD-1 blockade could be a safe and effective treatment option for dMMR metastatic colorectal cancer. The study highlights the potential of this combination therapy in achieving deep and long-lasting responses in dMMR colorectal cancers.

Predictive Signatures for Responses to Checkpoint Blockade in Small-Cell Lung Cancer in Second-Line Therapy Do Not Predict Responses in First-Line Patients.

Although immune checkpoint blockade (ICB) is currently approved for the treatment of extensive-stage small-cell lung cancer (SCLC) in combination with chemotherapy, relatively few patients have demonstrated durable clinical benefit (DCB) to these therapies. Biomarkers predicting responses are needed. Biopsies from 35 SCLC patients treated with ICB were subjected to transcriptomic analysis; gene signatures were assessed for associations with responses. Twenty-one patients were treated with ICB in the first-line setting in combination with platinum-based chemotherapy; fourteen patients were treated in the second-line setting with ICB alone. DCB after ICB in SCLC in the second-line setting (3 of 14 patients) was associated with statistically higher transcriptomic levels of genes associated with inflammation (p = 0.003), antigen presentation machinery (p = 0.03), interferon responses (p < 0.05), and increased CD8 T cells (p = 0.02). In contrast, these gene signatures were not significantly different in the first-line setting. Our data suggest that responses to ICB in SCLC in the second-line setting can be predicted by the baseline inflammatory state of the tumor; however, this strong association with inflammation was not seen in the first-line setting. We postulate that chemotherapy alters the immune milieu allowing a response to ICB. Other biomarkers will be needed to predict responses in first-line therapy patients.

Linoleoyl-lysophosphatidylcholine suppresses immune-related adverse events due to immune checkpoint blockade.

Immune related adverse events (irAEs) after immune checkpoint blockade (ICB) therapy occur in a significant proportion of cancer patients. To date, the circulating mediators of ICB-irAEs remain poorly understood. Using non-targeted mass spectrometry, here we identify the circulating bio-active lipid linoleoyl-lysophosphatidylcholine (LPC 18:2) as a modulator of ICB-irAEs. In three independent human studies of ICB treatment for solid tumor, loss of circulating LPC 18:2 preceded the development of severe irAEs across multiple organ systems. In both healthy humans and severe ICB-irAE patients, low LPC 18:2 was found to correlate with high blood neutrophilia. Reduced LPC 18:2 biosynthesis was confirmed in preclinical ICB-irAE models, and LPC 18:2 supplementation in vivo suppressed neutrophilia and tissue inflammation without impacting ICB anti-tumor response. Results indicate that circulating LPC 18:2 suppresses human ICB-irAEs, and LPC 18:2 supplementation may improve ICB outcomes by preventing severe inflammation while maintaining anti-tumor immunity.

Tertiary lymphoid structures in anticancer immunity.

Tertiary lymphoid structures (TLS) are transient ectopic lymphoid aggregates where adaptive antitumour cellular and humoral responses can be elaborated. Initially described in non-small cell lung cancer as functional immune lymphoid structures associated with better clinical outcome, TLS have also been found in many other carcinomas, as well as melanomas and sarcomas, and associated with improved response to immunotherapy. The manipulation of TLS as a therapeutic strategy is now coming of age owing to the likely role of TLS in the improved survival of patients with cancer receiving immune checkpoint inhibitor treatment. TLS have also garnered considerable interest as a predictive biomarker of the response to antitumour therapies, including immune checkpoint blockade and, possibly, chemotherapy. However, several important questions still remain regarding the definition of TLS in terms of both their cellular composition and functions. Here, we summarize the current views on the composition of TLS at different stages of their development. We also discuss the role of B cells and T cells associated with TLS and their dialogue in mounting antibody and cellular antitumour responses, as well as some of the various mechanisms that negatively regulate antitumour activity of TLS. The prognostic value of TLS to the clinical outcome of patients with cancer and the relationship between TLS and the response to therapy are then addressed. Finally, we present some preclinical evidence that favours the idea that manipulating the formation and function of TLS could lead to a potent next-generation cancer immunotherapy.

ALDH1A1 promotes immune escape of tumor cells through ZBTB7B-glycolysis pathway

The primary impediment to the success of immunotherapy lies in the immune evasion orchestrated by tumors, contributing to the suboptimal overall response rates observed. Despite this recognition, the intricacies of the underlying mechanisms remain incompletely understood. Through preliminary detection of clinical patient tissues, we have found that ALDH1A1 was a key gene for the prognosis of cancer patients and tumor glycolysis. In vitro experiments and tumor formation in nude mice suggested that targeting ALDH1A1 could inhibit tumor growth. Through further analysis of xenograft tumor models in immune-normal mice and flow cytometry, we found that deficiency in ALDH1A1 could promote immune system suppression of tumors in vivo. Specifically, RNA-seq analysis, combined with qPCR and western blot, identified the transcription factor ZBTB7B as downstream of ALDH1A1. The binding sites of the transcription factor ZBTB7B on the LDHA promoter region, which is responsible for regulating the rate-limiting enzyme gene LDHA in glycolysis, were determined using luciferase reporter gene detection and Chip-qPCR, respectively. In addition, the increased SUMOylation of ZBTB7B stabilized its transcriptional activity. Further in vivo and in vitro experiments confirmed that the combination of targeting ALDH1A1 and ZBTB7B with immune checkpoint inhibitors could synergistically inhibit tumors in vivo. Finally, after conducting additional verification of patient tissue and clinical data, we have confirmed the potential translational value of targeting ALDH1A1 and ZBTB7B for tumor immunotherapy. These results emphasize the potential translational significance of targeting ALDH1A1 and ZBTB7B in the realm of tumor immunotherapy. The convergence of ALDH1A1 inhibition and immune checkpoint blockade, particularly with PD-L1/PD-1 mAb, presents a compelling avenue for curtailing tumor immune escape.

53BP1 loss elicits cGAS-STING-dependent antitumor immunity in ovarian and pancreatic cancer

53BP1 nucleates the anti-end resection machinery at DNA double-strand breaks, thereby countering BRCA1 activity. Loss of 53BP1 leads to DNA end processing and homologous recombination in BRCA1-deficient cells. Consequently, BRCA1-mutant tumors, typically sensitive to PARP inhibitors (PARPi), become resistant in the absence of 53BP1. Here, we demonstrate that the ‘leaky’ DNA end resection in the absence of 53BP1 results in increased micronuclei and cytoplasmic double-stranded DNA, leading to activation of the cGAS-STING pathway and pro-inflammatory signaling. This enhances CD8+ T cell infiltration, activates macrophages and natural killer cells, and impedes tumor growth. Loss of 53BP1 correlates with a response to immune checkpoint blockade (ICB) and improved overall survival. Immunohistochemical assessment of 53BP1 in two malignancies, high grade serous ovarian cancer and pancreatic ductal adenocarcinoma, which are refractory to ICBs, reveals that lower 53BP1 levels correlate with an increased adaptive and innate immune response. Finally, BRCA1-deficient tumors that develop resistance to PARPi due to the loss of 53BP1 are susceptible to ICB. Therefore, we conclude that 53BP1 is critical for tumor immunogenicity and underpins the response to ICB. Our results support including 53BP1 expression as an exploratory biomarker in ICB trials for malignancies typically refractory to immunotherapy.

26 Applying single cell RNA sequencing of sarcomatoid renal cell carcinoma for the development of a novel transcriptomic biomarker to predict immunotherapy response

Abstract Background Renal cell carcinoma with sarcomatoid features (sRCC) is a unique kidney cancer subtype associated with aggressive biology and poor clinical outcomes. Intriguingly, sRCC has recently exhibited preferential responsiveness to immune checkpoint blockade (ICB) therapies. Within the RCC population, however, there currently is a paucity of biomarkers predictive for ICB response, representing a critical unmet clinical need for optimal therapy selection. Therefore, we sought to derive a transcriptomic signature from sRCC samples encapsulating this paradoxical hyper-aggression and ICB-responsiveness to identify RCC patients most likely to benefit from ICB irrespective of sarcomatoid feature presence. Methods Nephrectomy specimens from patients with RCC were processed for single cell RNA sequencing (scRNAseq). Clustering was performed and annotated tumor cells were computationally isolated. Tumor cell counts were aggregated and differential expression between sRCC and non-sRCC cases was performed. Genes significantly upregulated in sRCC were next filtered against differential gene expression data of sRCC vs non-sRCC from three clinical RCC datasets (TCGA, CheckMate, &amp; Javelin101) to identify genes enriched in sRCC across scRNAseq and bulk RNA sequencing. The prognostic and predictive features of this gene signature were then assessed in cohorts of patients with RCC receiving ICB. Results In total, 73,123 unique cells from 18 RCC patients (10 sRCC; 8 clear cell RCC) were analyzed by scRNAseq, including 5,386 tumor cells. Differential gene expression of tumor clones revealed 20 genes significantly enriched in sRCC relative to ccRCC. Filtering against public differential gene expression data resulted in 10 genes included within the final Sarcomatoid Signature (SS). SS expression scores for clinical specimens were calculated by single-sample gene set enrichment analysis. SS scores were significantly enriched in sRCC patient tumors across TCGA KIRC, CheckMate, and IMmotion151 datasets (p&amp;lt;0.001 for all cohorts). Within TCGA KIRC, SS scores were significantly increased in patients with nuclear grade 4 (p&amp;lt;0.001) and metastatic (p&amp;lt;0.001) disease, while stratification by median SS score revealed worsened overall (HR=2.19, p&amp;lt;0.001) and disease-free (HR=2.08, p&amp;lt;0.001) survival among SS-high patients. Amongst the CheckMate cohort (including patient samples from the CheckMate-010 &amp; CheckMate-025 trials), SS-high patients experienced improved progression free survival (PFS) when treated with nivolumab relative to everolimus (HR=0.70, p=0.055), whereas no difference was seen between therapies in the SS-low patient population (HR=0.98, p=0.9). In the IMmotion151 trial, which was not utilized for gene filtering and signature refinement and thus represents an independent validation cohort, SS-high patients experienced reduced PFS duration (HR=1.39, p&amp;lt;0.001) irrespective of treatment arm. However, SS-high patients experienced improved objective response rates with the ICB-containing atezolizumab/bevacizumab regimen compared to sunitinib (p&amp;lt;0.001) and relative to SS-low patients receiving atezolizumab/bevacizumab (p=0.028) (Figure 1). Within the SS-high population, patients experienced prolonged PFS with atezolizumab/bevacizumab (HR=0.70, p=0.003) relative to sunitinib whereas no PFS difference between arms was seen in the SS-low population (HR=1.01, p&amp;gt;0.99). Conclusions This novel SS derived from scRNAseq demonstrates negative prognostic yet positive predictive value for ICB response. In a domain currently void of efficacious biomarkers, the SS, upon prospective validation, may assist in optimal therapy selection for patients with RCC.

58 Tumor immune microenvironment determinants of response to Lenvatinib and aPD-1 blockade in clear cell renal cell carcinoma

Abstract Background Combinations of immune checkpoint blockade (ICB) and anti-angiogenesis tyrosine kinase inhibitors (TKI) are the mainstay of metastatic ccRCC front-line treatment, but heterogenous responses and lack of biomarkers strongly emphasizes the need to understand RCC-specific mechanisms of effective treatment-related anti-tumor immunity. Although prior work consistently highlights tumor associated macrophages (TAMs) in RCC prognosis and treatment response, TAM targeting has yet to experimentally assessed as a viable treatment sensitizer. Methods We therefore assessed the impact of TAM depletion using a clinical-grade colony stimulating factor receptor-1 inhibitor (CSF1Ri) on ICB or TKI sensitivity in a spontaneous mouse model of ccRCC with inducible kidney-specific Vhl, p53 and Rb1 deletions (KVpR). Mice were randomized to receive either no treatment, single agent Lenvatinib (TKI), aPD-1, or combinations with CSF1Ri. We longitudinally monitored a total of 307 tumors from 96 mice using magnetic resonance imaging (MRI) and collected responding and non-responding tumors for single cell RNA sequencing (scRNAseq) to elucidate the underlying mechanisms of response. Results Surprisingly we found that TAM depletion abolished aPD-1 response, with no effect on Lenvatinib response. ScRNAseq analyses suggest that CSF1R selectively depletes antigen presenting TAMs, leading to a striking loss of T cell infiltration. This suggests that TAMs, rather than dendritic cells as shown in other cancer types, may play a dominant role in eliciting T cells during aPD-1 therapy in RCC. On the other hand, Lenvatinib, which elicited a stronger T cell response than aPD-1, was associated with significant increases in cDC1 and plasma cells in responders, together suggesting that these two treatment modalities may operate through distinct antigen-presenting cells. Also unexpectedly, we found that both Lenvatinib and CSF1Ri induced severe intratumor hypoxia, which is typically associated with poor outcomes in most cancers. We identify a hypoxic niche-specific TAM subset that when abundant at baseline is predictive for poor response to ICB/TKI combos across multiple RCC trials, but post-treatment seems to capture hypoxia-mediated tumor cell death in responders in mouse and humans. We therefore wondered whether high levels of existing tumor hypoxia would exacerbate TKI-induced hypoxia leading to worst outcomes and found that in two novel RCC syngeneic models with high-baseline hypoxia, TKI indeed augments metastatic disease. Conclusions Our results offer mechanistic insight into the failure of CSF1R-based TAM depletion approaches in clinical trials and presents cautionary evidence against the use of hypoxia-inducing agents in tumors with high-baseline hypoxia. We show that TKI and ICB-induce distinct TME and hypoxia-related changes which require further study. More generally our study strongly emphasizes the importance of developing mechanism-guided clinical biomarkers. DOD CDMRP Funding: yes

An engineered self-biomineralized oncolytic adenovirus induces effective antitumor immunity and synergizes with immune checkpoint blockade.

Oncolytic adenoviruses (oADV) are promising cancer treatment agents. However, in vivo hepatic sequestration and the host immunological response against the agents limit the therapeutic potential of oADVs. Herein, we present a combined, rational design method for improving oADV infection efficiency, immunogenicity, and treatment efficacy by self-biomineralization. We integrated the biomimetic nucleopeptide W6p into the capsid of oADV using reverse genetics, allowing calcium phosphate mineralization to be biologically induced on the surface of oADV under physiological conditions, resulting in a mineral exterior. This self-biomineralized, modified oADV (oADV-W6-CaP) enhanced infection efficiency and therapeutic efficacy in coxsackie and adenovirus receptor (CAR)-negative cancer cells while protecting them against neutralization by pre-existing neutralizing antibodies. In subcutaneous mouse tumor models, systemic injection of oADV-W6-CaP demonstrated improved antitumor effectiveness, which was associated with increased T-cell infiltration and CD8+ T-cell activation. In addition, the anticancer immune response elicited by oADV-W6-CaP was dependent on CD8+ T cells, which mediated long-term immunological memory and systemic antitumor immunity against the same tumor. Finally, the addition of PD-1 or CD47 inhibition boosted the anticancer effects of oADV-W6-CaP and raised the rate of complete tumor clearance in tumor-bearing animals. The self-biomineralized oADV shifted the suppressive tumor microenvironment from a "cold" state to a "hot" state and synergized with immune checkpoint blockade to exert outstanding tumoricidal effects, demonstrating promising potential for cancer immunotherapy.

NaCe0.7FX:Gd0.1,Tb0.2 nanoscintillator as a new sonosensitizer for potentiating cancer sonodynamic-immune therapy

Trends in sonodynamic therapy (SDT) have stimulated greater research efforts toward the development of novel sonosensitizers due to their crucial roles in increasing reactive oxygen species (ROS). Herein, a new scintillator, NaCe0.7FX:Gd0.1,Tb0.2, was explored as an ultrasmall inorganic sonosensitizer for glutathione (GSH) depletion-enhanced SDT of cancer. Specifically, fluorine vacancy-donated defective NaCe0.7FX:Gd0.1,Tb0.2 scintillating nanodots (ScNDs) were prepared via a high-temperature reaction method. PEGylated ScNDs, namely ScND-PEG, exhausted GSH at first, which further augmented the sonodynamic performance of ROS generation. In vitro studies demonstrated that US-irradiated ScND-PEG exerted significant cytotoxicity on CT26 tumor cells by triggering immunogenic cell death (ICD). In vivo studies revealed that ScND-PEG-mediated enhanced SDT substantially inhibited tumor development by activating cytotoxic T lymphocytes and secreting antitumor proinflammatory cytokines. With the assistance of immune checkpoint blockade (ICB), improved antitumor outcomes were further obtained with prolonged survival time. Notably, no significant acute or chronic toxicity occurred during our treatment schedule based on ScND-PEG. Overall, our findings paved the way for identifying a new kind of ScND-based inorganic sonosensitizer as a reserve, which might open up new opportunities for advancing sonodynamic-immune oncotherapy.

25 Enrichment of tertiary lymphoid structures provides novel insight into mediators of anti-tumor immune activity in sarcomatoid renal cell carcinoma

Abstract Background Renal cell carcinoma (RCC) comprises various histological subtypes, with clear cell RCC (ccRCC) being the most prevalent histotype. RCC with sarcomatoid features (sRCC) is a unique kidney cancer subtype associated with aggressive biological features and poor clinical outcomes that can arise from multiple RCC histologies, most commonly ccRCC. While clinically aggressive, sRCC paradoxically has also demonstrated preferential responsiveness to immune checkpoint blockade (ICB) therapies in subgroup analyses of multiple phase III trials. However, the mediators of this immune sensitivity are largely unknown. We therefore applied transcriptomic techniques to identify orchestrators of immune activity within the sRCC tumor microenvironment (TME). Methods Nephrectomy specimens from patients with sRCC and ccRCC were procured for single cell RNA sequencing (scRNAseq). Clustering and dimensionality reduction were performed, and cell populations were annotated based on expression of canonical lineage markers. Immune populations (CD8+ T cells, CD4+ T cells, B/plasma cells, myeloid cells) were computationally extracted and differential gene expression between sRCC- and ccRCC-derived cells within each subpopulation was performed. Gene expression programs enriched in sRCC samples by scRNAseq were validated on publicly available bulk gene expression data comparing sRCC to ccRCC. Spatial transcriptomics were performed on sRCC tumor sections using the 10X Visium platform. Results Across 18 RCC specimens (10 sRCC; 8 ccRCC), 73,123 cells were analyzed by scRNAseq. Within the CD8+ T cell compartment, CXCL13 was the most significantly enriched nuclear-encoded gene in sRCC samples (log 2-fold change=1.29; q&amp;lt;0.001). CXCL13 was also significantly enriched in CD4+ T cells from sRCC (q&amp;lt;0.001), suggesting enhanced presence of follicular T cells within the sRCC TME. As follicular T cells function in support of B cells, we next interrogated the B lymphocyte population. sRCC samples were enriched for mature B cell and plasma cells, with a five-fold increase in the relative abundance of plasma cells compared to ccRCC samples. Immune deconvolution of patient-derived RNA sequencing from the IMmotion 151 trial revealed a significant increase in the predicted proportion of B lymphocytes (including plasma cells) within the sRCC TME relative to ccRCC (p=0.034). Further, over 20 B lymphocyte activation and maturation pathways were consistently enriched (q&amp;lt;0.25) in sRCC across clinical datasets (Javelin101, CheckMate, and TCGA KIPAN), including Signaling by the B Cell Receptor, Positive Regulation of B Cell Activation, and Immunoglobulin Production Involved in Immunoglobulin Mediated Immune Response, amongst others. B lymphocytes mediate anti-tumor immunity through antibody dependent cellular cytotoxicity (ADCC), and thus the phagocytic effectors of ADCC were interrogated. Myeloid populations differentially expressed FCγR3A in sRCC vs ccRCC (q&amp;lt;0.001), which was recapitulated in bulk gene expression populations (q=0.002, 0.12, and 1.08x10-4 in Javelin101, CheckMate, and TCGA cohorts, respectively). Given the enrichment of follicular T cell and differentiated B lymphocyte programs, we explored the presence of tertiary lymphoid structures (TLS) in sRCC. Two distinct TLS signatures – the 12 Chemokine Score and the TLS Imprint Signature – were significantly enriched in sRCC vs ccRCC across RCC patient datasets (Figure 1). Furthermore, spatial transcriptomics were applied to H&amp;E slides of sRCC to successfully identify the presence of TLS by expression of TLS-associated genes adjacent to sarcomatoid regions. Conclusions TLS, which have previously been associated with response to ICB in RCC (Meylan et al. Immunity. 2022), are transcriptomically enriched for in sRCC, paralleling an observed increase in CXCL13-expressing T cells and differentiated B lymphocytes. Together, TLS and their constituents offer a previously unexplored mediator of immunosurveillance in the sRCC TME that may underlie the paradoxical responsiveness to ICB seen within this population clinically.

Microspheres-mediated magnetic thermal ablation combined with immune checkpoint blockade therapy for liver cancer

Hepatocellular carcinoma (HCC) are some of the most difficult malignant tumors to treat, due to their high rates of metastasis and recurrence. Image-guided percutaneous ablation, which serves as an important means in HCC treatment. However, drawbacks such as puncture injury, metastasis, and a limited ablation range still exist. Therefore, A highly effective and non-invasive magnetic thermal ablation (MTA) scheme for HCC was proposed by precisely embolizing magnetic microspheres into tumor-feeding arteries. In this study, polyacrylamide (PAM) and ferric oxide (Fe3O4) were utilized to prepare uniformly sized PAM@Fe3O4 microspheres with excellent eddy current heating effects. Additionally, a combined approach of MTA and immunotherapy was suggested. MTA combined with immune checkpoint blockade therapy efficiently ablated primary tumors and inhibited simulated metastatic tumors in mice. Further arterial embolization experiments in rabbit ears and renal arteries demonstrated the effective retention of PAM@Fe3O4 microspheres in blood vessels for MTA. Finally, we successfully applied PAM@Fe3O4 microspheres for efficient MTA therapy in a rabbit VX2 in situ liver tumor model. The aim of research is to provide new strategies for clinical HCC treatment, promoting the transition from image-guided percutaneous minimally invasive ablation to noninvasive ablation. This significant transition holds the potential for clinical applicability.