Immune Checkpoint Blockade Research Articles

PD-L1 blockade immunotherapy rewires cancer-induced emergency myelopoiesis.

Immune checkpoint blockade (ICB) immunotherapy has revolutionized cancer treatment, demonstrating exceptional clinical responses in a wide range of cancers. Despite the success, a significant proportion of patients still fail to respond, highlighting the existence of unappreciated mechanisms of immunotherapy resistance. Delineating such mechanisms is paramount to minimize immunotherapy failures and optimize the clinical benefit. In this study, we treated tumour-bearing mice with PD-L1 blockage antibody (aPD-L1) immunotherapy, to investigate its effects on cancer-induced emergency myelopoiesis, focusing on bone marrow (BM) hematopoietic stem and progenitor cells (HSPCs). We examined the impact of aPD-L1 treatment on HSPC quiescence, proliferation, transcriptomic profile, and functionality. Herein, we reveal that aPD-L1 in tumour-bearing mice targets the HSPCs in the BM, mediating their exit from quiescence and promoting their proliferation. Notably, disruption of the PDL1/PD1 axis induces transcriptomic reprogramming in HSPCs, observed in both individuals with Hodgkin lymphoma (HL) and tumour-bearing mice, shifting towards an inflammatory state. Furthermore, HSPCs from aPDL1-treated mice demonstrated resistance to cancer-induced emergency myelopoiesis, evidenced by a lower generation of MDSCs compared to control-treated mice. Our findings shed light on unrecognized mechanisms of action of ICB immunotherapy in cancer, which involves targeting of BM-driven HSPCs and reprogramming of cancer-induced emergency myelopoiesis.

Bidirectional regulation of the cGAS-STING pathway in the immunosuppressive tumor microenvironment and its association with immunotherapy.

Adaptive anti-tumor immunity is currently dependent on the natural immune system of the body. The emergence of tumor immunotherapy has improved prognosis and prolonged the survival cycle of patients. Current mainstream immunotherapies, including immune checkpoint blockade, chimeric antigen receptor T-cell immunotherapy, and monoclonal antibody therapy, are linked to natural immunity. The cGAS-STING pathway is an important natural immunity signaling pathway that plays an important role in fighting against the invasion of foreign pathogens and maintaining the homeostasis of the organism. Increasing evidence suggests that the cGAS-STING pathway plays a key role in tumor immunity, and the combination of STING-related agonists can significantly enhance the efficacy of immunotherapy and reduce the emergence of immunotherapeutic resistance. However, the cGAS-STING pathway is a double-edged sword, and its activation can enhance anti-tumor immunity and immunosuppression. Immunosuppressive cells, including M2 macrophages, MDSC, and regulatory T cells, in the tumor microenvironment play a crucial role in tumor escape, thereby affecting the immunotherapy effect. The cGAS-STING signaling pathway can bi-directionally regulate this group of immunosuppressive cells, and targeting this pathway can affect the function of immunosuppressive cells, providing new ideas for immunotherapy. In this study, we summarize the activation pathway of the cGAS-STING pathway and its immunological function and elaborate on the key role of this pathway in immune escape mediated by the tumor immunosuppressive microenvironment. Finally, we summarize the mainstream immunotherapeutic approaches related to this pathway and explore ways to improve them, thereby providing guidelines for further clinical services.

Tumor specific in situ synthesis of therapeutic agent for precision cancer therapy

BackgroundTraditional chemotherapeutic agents suffer from a lack of selectivity, poor targeting ability, and drug resistance. Developing tumor-specific therapies is crucial for precisely eliminating tumors while circumventing toxicity to normal tissues. Disulfiram (DSF), an FDA-approved drug for treating alcohol dependence, exhibits antitumor effect by forming complexes with copper ions (Cu(DDC)2). Here, we developed a Cu-doped polydopamine-based nanosystem (DSF@CuPDA-PEGM) to achieve in situ generation of toxic Cu(DDC)2.ResultsIn cancer cells with elevated H2O2 contents, CuPDA responsively degrades to release Cu ions and DSF, allowing on-site synthesis of Cu(DDC)2 with potent antitumor activity. DSF@CuPDA-PEGM exhibits excellent therapeutic efficacy against both drug-sensitive and drug-resistant cancer cells while minimizing toxicity to noncancerous cells. Moreover, DSF@CuPDA-PEGM promotes the immune response by inducing cancer cell immunogenic death, thereby augmenting anti-PD-1-based immune checkpoint blockade therapy.ConclusionA tumor-specifically degradable Cu-doped polydopamine-based nanosystem is developed to achieve in situ synthesis of antitumor compounds, providing a promising approach to precisely eliminate tumors and heighten chemo-immunotherapy.Graphical

IMMUNE AND MOLECULAR CORRELATES OF RESPONSE TO IMMUNOTHERAPY REVEALED BY BRAIN-METASTATIC MELANOMA MODELS.

Despite the promising results of immune checkpoint blockade (ICB) therapy, outcomes for patients with brain metastasis (BrM) remain poor. Identifying resistance mechanisms has been hindered by limited access to patient samples and relevant preclinical models. Here, we developed two mouse melanoma BrM models that recapitulate the disparate responses to ICB seen in patients. We demonstrate that these models capture the cellular and molecular complexity of human disease and reveal key factors shaping the tumor microenvironment and influencing ICB response. BR1-responsive tumor cells express inflammatory programs that polarize microglia into reactive states, eliciting robust T cell recruitment. In contrast, BR3-resistant melanoma cells are enriched in neurological programs and exploit tolerance mechanisms to maintain microglia homeostasis and limit T cell infiltration. In humans, BR1 and BR3 expression signatures correlate positively or negatively with T cell infiltration and BrM patient outcomes, respectively. Our study provides clinically relevant models and uncovers mechanistic insights into BrM ICB responses, offering potential biomarkers and therapeutic targets to improve therapy efficacy.

CTLA4 blockade abrogates KEAP1/STK11-related resistance to PD-(L)1 inhibitors.

For patients with advanced non-small-cell lung cancer (NSCLC), dual immune checkpoint blockade (ICB) with CTLA4 inhibitors and PD-1 or PD-L1 inhibitors (hereafter, PD-(L)1 inhibitors) is associated with higher rates of anti-tumour activity and immune-related toxicities, when compared with treatment with PD-(L)1 inhibitors alone. However, there are currently no validated biomarkers to identify which patients willbenefit from dual ICB1,2. Here we show that patients with NSCLC who have mutations in the STK11 and/or KEAP1 tumour suppressor genes derived clinical benefit from dual ICB with the PD-L1 inhibitor durvalumab and the CTLA4 inhibitor tremelimumab, but not from durvalumab alone, when added to chemotherapy in the randomized phase III POSEIDON trial3. Unbiased genetic screens identified loss of both of these tumour suppressor genes as independent drivers of resistance to PD-(L)1 inhibition, and showed that loss of Keap1 was the strongest genomic predictor of dual ICB efficacy-a finding that was confirmed in several mouse models of Kras-driven NSCLC. In both mouse models and patients, KEAP1 and STK11 alterations were associated with an adverse tumour microenvironment, which was characterized by a preponderance of suppressive myeloid cells and the depletion of CD8+ cytotoxic T cells, but relative sparing of CD4+ effector subsets. Dual ICB potently engaged CD4+ effector cells and reprogrammed the tumour myeloid cell compartment towards inducible nitric oxide synthase (iNOS)-expressing tumoricidal phenotypes that-together with CD4+ and CD8+ T cells-contributed to anti-tumour efficacy. These data support the use of chemo-immunotherapy with dual ICB to mitigate resistance to PD-(L)1 inhibition in patients with NSCLC who have STK11 and/or KEAP1 alterations.

Riluzole Enhancing anti-PD-1 Efficacy by Activating cGAS/STING Signaling in Colorectal Cancer.

Colorectal cancer is the second leading cause of cancer mortality in the US. Although immune checkpoint blockade therapies including anti-PD-1/PD-L1 have been successful in treating a subset of colorectal cancer patients, response rates remain low. We have found that riluzole, a well-tolerated FDA-approved oral medicine for treating amyotrophic lateral sclerosis, increased intratumoral CD8+ T cells and suppressed tumor growth of colon cancer cells in syngeneic immune competent mice. Riluzole-mediated tumor suppression was dependent on the presence of CD8+ T cells. Riluzole activates the cytosolic DNA sensing cGAS/STING pathway in colon cancer cells, resulting in increased expression of interferon β (IFNβ) and IFNβ-regulated genes including CXCL10. Inhibition of ATM, but not ATR, resulted in a synergistic increase in IFNβ expression, suggesting that riluzole induces ATM-mediated damage response that contribute to cGAS/STING activation. Depletion of cGAS or STING significantly attenuated riluzole-induced expression of IFNβ and CXCL10 as well as increase of intratumoral CD8+ T cells and suppression of tumor growth. These results indicate that riluzole-mediated tumor infiltration of CD8+ T cells and attenuation of tumor growth is dependent on tumor cell intrinsic STING activation. To determine whether riluzole treatment primes the tumor microenvironment for immune checkpoint modulation, riluzole was combined with anti-PD-1 treatment. This combination showed greater efficacy than either single agent, and strongly suppressed tumor growth in vivo. Taken together, our studies indicate that riluzole activates cGAS/STING-mediated innate immune responses, which might be exploited to sensitize colorectal tumors to anti-PD-1/PD-L1 therapies. .

The impact of demographics and socioeconomic status on the receipt of immunotherapy for stage III melanoma

BackgroundThere is limited data examining potential disparities in the receipt of immunotherapy among patients with stage III melanoma. MethodsWe performed a retrospective cohort review using the National Cancer Database (NCDB) including adult patients with stage III melanoma between 2004 and 2017. We compared receipt of immunotherapy based on demographic and socioeconomic factors for patients diagnosed 2004–2014 and 2016–2017, before and after FDA approval of immune checkpoint blockade. Results12,099 patients were included. The proportion of stage III patients who received immunotherapy significantly increased over time, from 24.0 % in 2004–2014 to 43.7 % in 2016–2017 (p < 0.001). There was a significant difference in patients who receive immunotherapy based on age (p < 0.001), insurance (p < 0.001), facility location (p < 0.001).On multivariable analysis, increased odds of immunotherapy receipt were found in patients with diagnosis in 2016–2017 (adjusted odds ratio (aOR) 3.3, 95 % CI 2.9–3.7), younger age (65–80 years aOR 0.43, 95 % CI 0.35–0.52), Hispanic ethnicity (aOR 1.5, 95 % CI 1.1–2.1), and private insurance (not insured aOR 0.67, 95 % CI 0.52–0.85). ConclusionsAlthough narrowing, gaps persist in the receipt of immunotherapy after FDA approval. Understanding disparities in the receipt of immunotherapy will aid in understanding barriers to treatment and ensuring patients have equitable access to advanced care.

Use pembrolizumab may cause acute and severe adverse reactions: a case report and review

Introduction: Immune checkpoint inhibitors (ICIs) have emerged as pivotal therapeutics for personalized cancer treatment. Programmed death protein receptor 1/ligand 1 (PD-1/PD-L1) inhibitors represent the most extensively utilized immune checkpoint blockade agents. Among these, pembrolizumab has gained approval for advanced cancer management. By engaging with PD-1 on T cells, pembrolizumab orchestrates the immune response against tumor cells; however, it is also associated with a spectrum of adverse events, including an infrequent manifestation of fulminant type 1 diabetes. Case presentation: ICIs-induced fulminant type 1 diabetes mellitus (FT1DM) in breast cancer patients has been rarely documented. To provide further evidence of such adverse events, this paper presents the case of a 58-year-old Chinese patient with breast cancer and multi-organ metastasis, who had no prior history of diabetes. Following five courses of pembrolizumab, she developed severe fulminant type 1 diabetes accompanied by ketoacidosis. Discussion: Pembrolizumab is commonly utilized in the treatment of patients with advanced cancer. While it offers significant benefits to patients, it can also lead to numerous adverse reactions, with immune-related diabetes being the most prevalent among them as a result of pembrolizumab usage. Conclusions: FT1DM complicated with ketoacidosis represents a critical and potentially life-threatening medical condition, necessitating immediate attention. Our case study underscores the inherent risks associated with pembrolizumab administration and offers valuable insights for its safe utilization in patients.

Two-dimensional coordination risedronate-manganese nanobelts as adjuvant for cancer radiotherapy and immunotherapy

The irradiated tumor itself represents an opportunity to establish endogenous in situ vaccines. However, such in situ cancer vaccination (ISCV) triggered by radiation therapy (RT) alone is very weak and hardly elicits systemic anticancer immunity. In this study, we develop two-dimensional risedronate-manganese nanobelts (RMn-NBs) as an adjuvant for RT to address this issue. RMn-NBs exhibit good T2 magnetic resonance imaging performance and enhanced Fenton-like catalytic activity, which induces immunogenic cell death. RMn-NBs can inhibit the HIF-1α/VEGF axis to empower RT and synchronously activate the cGAS/STING pathway for promoting the secretion of type I interferon, thereby boosting RT-triggered ISCV and immune checkpoint blockade therapy against primary and metastatic tumors. RMn-NBs as a nano-adjuvant for RT show good biocompatibility and therapeutic efficacy, presenting a promising prospect for cancer radiotherapy and immunotherapy.

Towards a framework for predicting immunotherapy outcome: a hybrid multiscale mathematical model of immune response to vascular tumor growth.

Studying tumor immune microenvironment (TIME) is pivotal to understand the mechanism and predict the outcome of cancer immunotherapy. Systems biology mathematical models can consider and control various factors of TIME and therefore explore the anti-tumor immune response meticulously. However, the role of tumor vasculature in the recruitment of T cells and the mechanism of T cell migration through TIME have not been studied comprehensively. In this work, we developed a hybrid discrete-continuum multi-scale model to study TIME. The mathematical model includes angiogenesis and T cell recruitment via tumor vasculature. Moreover, solid tumor growth, vascular growth and remodeling, interstitial fluid flow, hemodynamics, and blood rheology are all considered in the model. In addition, different aspects of T cells, including their migration, proliferation, subtype conversion, and interaction with tumor cells are thoroughly included. The model reproduces spatiotemporal distribution of tumor infiltrating T cells that mimics histopathological patterns. Furthermore, TIME model robustly recapitulates different phases of tumor immunoediting. We also examined a number of biomarkers to predict the outcome of immune checkpoint blockade (ICB) treatment. The results demonstrated that although tumor mutational burden (TMB) may predict non-responders to ICB, a combination of different biomarkers is essential to predict the majority of the responders. Based on our results, the ICB response rate varies significantly from 28 to 89% depending on the values of different parameters, even in the cases with high TMB.

Alternative splicing of PBRM1 mediates resistance to PD-1 blockade therapy in renal cancer.

Alternative pre-mRNA splicing (AS) is a biological process that results in proteomic diversity. However, implications of AS alterations in cancer remain poorly understood. Herein, we performed a comprehensive AS analysis in cancer driver gene transcripts across fifteen cancer types and found global alterations in inclusion rates of the PBAF SWI/SNF chromatin remodeling complex subunit Polybromo 1 (PBRM1) exon 27 (E27) in most types of cancer tissues compared with those in normal tissues. Further analysis confirmed that PBRM1 E27 is excluded by the direct binding of RBFOX2 to intronic UGCAUG elements. In addition, the E27-included PBRM1 isoform upregulated PD-L1 expression via enhanced PBAF complex recruitment to the PD-L1 promoter. PBRM1wild-type patients with clear cell renal cell carcinoma were resistant to PD-1 blockade therapy when they expressed low RBFOX2 mRNA levels. Overall, our study suggests targeting of RBFOX2-mediated AS of PBRM1 as a potential therapeutic strategy for immune checkpoint blockade.

Polymeric nanocarrier via metabolism regulation mediates immunogenic cell death with spatiotemporal orchestration for cancer immunotherapy

The limited efficacy of cancer immunotherapy occurs due to the lack of spatiotemporal orchestration of adaptive immune response stimulation and immunosuppressive tumor microenvironment modulation. Herein, we report a nanoplatform fabricated using a pH-sensitive triblock copolymer synthesized by reversible addition-fragmentation chain transfer polymerization enabling in situ tumor vaccination and tumor-associated macrophages (TAMs) polarization. The nanocarrier itself can induce melanoma immunogenic cell death (ICD) via tertiary amines and thioethers concentrating on mitochondria to regulate metabolism in triggering endoplasmic reticulum stress and upregulating gasdermin D for pyroptosis as well as some features of ferroptosis and apoptosis. After the addition of ligand cyclic arginine-glycine-aspartic acid (cRGD) and mannose, the mixed nanocarrier with immune adjuvant resiquimod encapsulation can target B16F10 cells for in situ tumor vaccination and TAMs for M1 phenotype polarization. In vivo studies indicate that the mixed targeting nanoplatform elicits tumor ICD, dendritic cell maturation, TAM polarization, and cytotoxic T lymphocyte infiltration and inhibits melanoma volume growth. In combination with immune checkpoint blockade, the survival time of mice is markedly prolonged. This study provides a strategy for utilizing immunoactive materials in the innate and adaptive immune responses to augment cancer therapy.

Immune Checkpoint Blockade Therapies Efficacy and Toxicity in Patients With Impaired Renal Function in Metastatic Bladder Cancer

BackgroundIn this study, we reported the real-life results of data from impaired renal patients with urothelial carcinoma who were treated with ICTs. MethodsThe patients were categorized into 3 different groups GFR ≥60mL/min (normal), 60mL/min-30mL/min (low), and less than 30 mL/min (very low) based on GFR. The primary endpoints were the overall response rate (ORR), overall survival (OS), duration of response with ICT, and safety. Median follow-up and OS were estimated by using the Kaplan-Meier method. ResultsOne hundred-five (60.3%) of patients were GFR normal, 26.4% were GFR low with 30mL/min-60mL/min, and 13.2% were very low group. ORR for GFR normal, low and very low groups were 36% (n = 38), 26% (n = 12) and %31 (7); P = .2, respectively. The median duration of response for GFR normal, low and very low groups were 47.2 months (95% CI, 24.5-51.4), 33.1 months (95% CI, 26.9-47), and 23.5 months (95% CI, 12.2-43.7); P = .01, respectively. The Median OS rate for GFR normal, low and very low groups were 11.9 (7.2-16.5) months, 4.7 (1.8-7.7) and 6.8 (1.1-13.6) months, P = .015, respectively. In addition, GFR <60 ml/min HR = 1.6; 95% CI 1.12-1.80; P = .02, maintained a significant association with OS in multivariate analysis. ConclusionsLong-term follow-up of real-world data confirms that the overall survival rate and durable response rate with ICT were higher in patients with GFR >60mL/min. On the other hand, we demonstrated that ICT was effective and a durable response seen in a group of patients with renal inpairement who did not have an effective systemic treatment option.

Tumor necrosis factor superfamily signaling: life and death in cancer.

Immune checkpoint inhibitors have shaped the landscape of cancer treatment. However, many patients either do not respond or suffer from later progression. Numerous proteins can control immune system activity, including multiple tumor necrosis factor (TNF) superfamily (TNFSF) and TNF receptor superfamily (TNFRSF) members; these proteins play a complex role in regulating cell survival and death, cellular differentiation, and immune system activity. Notably, TNFSF/TNFRSF molecules may display either pro-tumoral or anti-tumoral activity, or even both, depending on tumor type. Therefore, TNF is a prototype of an enigmatic two-faced mediator in oncogenesis. To date, multiple anti-TNF agents have been approved and/or included in guidelines for treating autoimmune disorders and immune-related toxicities after immune checkpoint blockade for cancer. A confirmed role for the TNFSF/TNFRSF members in treating cancer has proven more elusive. In this review, we highlight the cancer-relevant TNFSF/TNFRSF family members, focusing on the death domain-containing and co-stimulation members and their signaling pathways, as well as their complicated role in the life and death of cancer cells.

Aristolochic acid-related renal cell carcinoma exhibits a distinct tumor-immune microenvironment favoring response to immune checkpoint blockade.

Immune checkpoint blockade (ICB) is currently the standard of care for metastatic renal cell carcinoma (RCC), but treatment responses remain unpredictable. Aristolochic acid (AA), a prevalent supplement additive in Taiwan, has been associated with RCC and induces signature mutations, although its effect on the tumor-immune microenvironment (TIME) is unclear. We aimed to investigate the immune profile of AA-positive RCCs and explore its potential role as a susceptible candidate for ICB. Tissue samples from 22 patients with clear cell RCC (ccRCC) were collected for whole-exome sequencing to determine the genetic features and AA mutational signature (the discovery cohort). The corresponding RNA was sent for NanoString PanCancer IO 360 gene expression analysis to explore the immunological features. The formalin-fixed, parafilm-embedded slides of ccRCCs were sent for multiplex immunohistochemistry/immunofluorescence stain using Vectra system to evaluate the TIME. Tissues from two patients with metastatic RCC demonstrating complete response to ICB were sent for studies to validate the findings (the index patients). The results showed that AA mutational signatures with high tumor mutational burden (TMB) were present in 31.81% of the tumors in the discovery cohort. Three distinct clusters were observed through NanoString analysis. Clusters 1 and 3 were composed mainly of AA-positive RCCs. Cluster 3 RCCs exhibited higher tumor inflammation signature scores and higher immune cell type scores. Vectra analysis revealed a higher percentage of CD15+ and BATF3+ cells in cluster 1, whereas the percentage of CD8+ cells was potentially higher in cluster 3. Strong AA mutational signatures were found in the tumors of two index patients, and both were grouped to cluster 3. In conclusion, AA may induce higher TMB and alter the immune microenvironment in RCCs, which makes the tumors more susceptible to ICB. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Development of a Mammalian Cell Line for Stable Production of Anti-PD-1.

Background/Objectives: Immune checkpoint blockade, particularly targeting the programmed cell death 1 (PD-1) receptor, is a promising strategy in cancer immunotherapy. The interaction between PD-1 and its ligands, PD-L1 and PD-L2, is crucial in immune evasion by tumors. Blocking this interaction with monoclonal antibodies like Nivolumab can restore anti-tumor immunity. This study aims to develop a stable expression system for Nivolumab-based anti-PD-1 in the Chinese Hamster Ovary (CHO) DG44 cell line using two different expression vector systems with various signal sequences. Methods: The heavy chain (HC) and light chain (LC) of Nivolumab were cloned into two expression vectors, pOptiVEC and pcDNA3.3. Each vector was engineered with two distinct signal sequences, resulting in the creation of eight recombinant plasmids. These plasmids were co-transfected into CHO DG44 cells in different combinations, allowing for the assessment of stable antibody production. Results: Both pOptiVEC and pcDNA3.3 vectors were successful in stably integrating and expressing the Nivolumab-based anti-PD-1 antibody in CHO DG44 cells. This study found that the choice of signal sequence significantly influenced the quantity of antibodies produced. The optimization of production conditions further enhanced antibody yield, indicating the potential for large-scale production. Conclusions: This study demonstrates that both pOptiVEC and pcDNA3.3 expression systems are effective for the stable production of Nivolumab-based anti-PD-1 in CHO DG44 cells. Signal sequences play a critical role in determining the expression levels, and optimizing production conditions can further increase antibody yield, supporting future applications in cancer immunotherapy.

Aberrant cytoplasmic expression of UHRF1 restrains the MHC-I-mediated anti-tumor immune response

Immunotherapy successfully complements traditional cancer treatment. However, primary and acquired resistance might limit efficacy. Reduced antigen presentation by MHC-I has been identified as potential resistance factor. Here we show that the epigenetic regulator ubiquitin-like with PHD and ring finger domains 1 (UHRF1), exhibits altered expression and aberrant cytosolic localization in cancerous tissues, where it promotes MHC-I ubiquitination and degradation. Cytoplasmic translocation of UHRF1 is induced by its phosphorylation on a specific serine in response to signals provided by factors present in the tumor microenvironment (TME), such as TGF-β, enabling UHRF1 to bind MHC-I. Downregulation of MHC-I results in suppression of the antigen presentation pathway to establish an immune hostile TME. UHRF1 inactivation by genetic deletion synergizes with immune checkpoint blockade (ICB) treatment and induces an anti-tumour memory response by evoking low-affinity T cells. Our study adds to the understanding of UHRF1 in cancer immune evasion and provides a potential target to synergize with immunotherapy and overcome immunotherapeutic resistance.

Immunogenic cell death signatures from on-treatment tumor specimens predict immune checkpoint therapy response in metastatic melanoma

Melanoma is a highly malignant form of skin cancer that typically originates from abnormal melanocytes. Despite significant advances in treating metastatic melanoma with immune checkpoint blockade (ICB) therapy, a substantial number of patients do not respond to this treatment and face risks of recurrence and metastasis. This study collected data from multiple datasets, including cohorts from Riaz et al., Gide et al., MGH, and Abril-Rodriguez et al., focusing on on-treatment samples during ICB therapy. We used the single-sample gene set enrichment analysis (ssGSEA) method to calculate immunogenic cell death scores (ICDS) and employed an elastic network algorithm to construct a model predicting ICB efficacy. By analyzing 18 ICD gene signatures, we identified 9 key ICD gene signatures that effectively predict ICB treatment response for on-treatment metastatic melanoma specimens. Results showed that patients with high ICD scores had significantly higher response rates to ICB therapy compared to those with low ICD scores. ROC analysis demonstrated that the AUC values for both the training and validation sets were around 0.8, indicating good predictive performance. Additionally, survival analysis revealed that patients with high ICD scores had longer progression-free survival (PFS). This study used an elastic network algorithm to identify 9 ICD gene signatures related to the immune response in metastatic melanoma. These gene features can not only predict the efficacy of ICB therapy but also provide references for clinical decision-making. The results indicate that ICD plays an important role in metastatic melanoma immunotherapy and that expressing ICD signatures can more accurately predict ICB treatment response and prognosis for on-treatment metastatic melanoma specimens, thus providing a basis for personalized treatment.

Rapid Assessment of Biomarkers on Single Extracellular Vesicles Using "Catch and Display" on Ultrathin Nanoporous Silicon Nitride Membranes.

Extracellular vesicles (EVs) are particles released from cells that facilitate intercellular communication and have tremendous diagnostic and therapeutic potential. Bulk assays lack the sensitivity to detect rare EV subsets relevant to disease, and while single EV analysis techniques remedy this, they are often undermined by complicated detection schemes and prohibitive instrumentation. To address these issues, a microfluidic technique for EV characterization called "catch and display for liquid biopsy (CAD-LB)" is proposed. In this method, minimally processed samples are pipette-injected and fluorescently labeled EVs are captured in the nanopores of an ultrathin membrane. This enables the rapid assessment of EV number and biomarker colocalization by light microscopy. Here, nanoparticles are used to define the accuracy and dynamic range for counting and colocalization. The same assessments are then made for purified EVs and for unpurified EVs in plasma. Biomarker detection is validated using CD9 and Western blot analysis to confirm that CAD-LB accurately reports relative protein expression levels. Using unprocessed conditioned media,CAD-LB captures the known increase in EV-associated ICAM-1 following endothelial cell cytokine stimulation. Finally, to demonstrate CAD-LB's clinical potential, EV biomarkers indicative of immunotherapy responsiveness are successfully detected in the plasma of bladder cancer patients treated with immune checkpoint blockade.

TIMP1 mediates astrocyte-dependent local immunosuppression in brain metastasis acting on infiltrating CD8+ T cells.

Immunotherapies against brain metastases have shown clinical benefits when applied to asymptomatic patients, but they are largely ineffective in symptomatic cases for unknown reasons. Here we dissect the heterogeneity in metastasis-associated astrocytes using scRNAseq and report a population that blocks the antitumoral activity of infiltrating T cells. This pro-tumoral activity is mediated by the secretion of TIMP1 from a cluster of pSTAT3+ astrocytes that acts on CD63+ CD8+ T cells to modulate their function. Using genetic and pharmacologic approaches in mouse and human brain metastasis models, we demonstrate that combining immune checkpoint blockade antibodies with the inhibition of astrocyte-mediated local immunosuppression may benefit patients with symptomatic brain metastases. We further reveal that the presence of TIMP1 in liquid biopsies provides a biomarker to select patients for this combined immunotherapy. Overall, our findings demonstrate an unexpected immunomodulatory role for astrocytes in brain metastases with clinical implications.