Cancer Immune Response Research Articles

Liposomal Nω-hydroxy-l-norarginine, a proof-of-concept: Arginase inhibitors can be incorporated in liposomes while retaining their therapeutic activity ex vivo

Cancer immunotherapy has evolved significantly over the last decade, with therapeutics targeting the adaptive immune system showing exciting effects in clinics. Yet, the modulation of the innate immune system, particularly the tumor-associated innate immune cells which are an integral part of immune responses in cancer, remains less understood. The arginase 1 (Arg1) pathway is a pivotal metabolic pathway that tumor-associated innate immune cells exploit to create an immunosuppressive tumor microenvironment, leading to the evasion of immune surveillance. The inhibition of Arg1 presents a therapeutic opportunity to reverse this immunosuppression, and Nω‑hydroxy-l-norarginine (nor-NOHA) has emerged as a potent arginase inhibitor with promising in vivo efficacy. However, the rapid systemic clearance of nor-NOHA poses a significant challenge for its therapeutic application. This study pioneers the encapsulation of nor-NOHA in liposomes, aiming to enhance its bioavailability and prolong its inhibitory activity against Arg1. Historically, the extensive interaction between innate immune cells and nanoparticles has been one of the biggest drawbacks in nanomedicine. Here we seek to utilize this effect and deliver liposomal nor-NOHA to the arginase 1 expressing innate immune cells. We systematically investigated the effect of lipid composition, acyl chain length, manufacturing and loading methodology on the encapsulation efficiency (EE%) and release profile of nor-NOHA. Our results indicate that while the manufacturing method and lipid acyl chain length do not significantly impact EE%, they crucially influence the release kinetics of nor-NOHA, with longer acyl chains demonstrating a more sustained release of nor-NOHA from liposomes enabling continuous inhibition of Arg1. Our findings suggest that liposomal nor-NOHA retains its functional inhibitory activity and could offer improved pharmacokinetic properties, making it a compelling base for iterations for further innovative cancer immunotherapeutic strategies in preclinical and clinical evaluations.

The role of calcium homeostasis in modulating the immune response in cancer and infectious diseases

Calcium homeostasis is a pivotal determinant of physiological processes, particularly in cellular signaling and immune system regulation. This balance is crucial for modulating immune responses in the context of both infectious and oncological diseases. Disruptions in calcium homeostasis have been shown to influence disease progression, immune efficacy, and treatment outcomes. Our study investigates the critical role of calcium homeostasis in shaping the immune response to cancer and infectious diseases through a comprehensive literature review. The electronic databases Scopus, Google Scholar, and PubMed were utilized to gather relevant studies, identified using key terms such as "calcium homeostasis," "immune response," "cancer," and "infectious diseases." Emerging evidence underscores that calcium levels directly impact immune cell function, including the activation of immune effector cells, cytokine production, and the orchestration of the overall immune response. These processes are critical to the body's ability to combat infections and malignancies. Aberrant calcium signaling may lead to compromised immune defense mechanisms, negatively affecting the outcomes of therapeutic interventions. In cancer, for example, altered calcium homeostasis can suppress immune surveillance, while in infectious diseases, it can hinder the immune system's capacity to clear pathogens. Our review highlights that the pathophysiology of both cancer and infectious diseases is tightly interwoven with calcium regulation, suggesting a promising avenue for therapeutic targeting. Modulating calcium homeostasis may enhance immune functionality, thereby improving treatment efficacy. By restoring calcium balance, novel therapeutic approaches could be developed to optimize immune responses and bolster clinical outcomes across a range of diseases. Further research is warranted to elucidate the precise molecular mechanisms linking calcium homeostasis and immune regulation, with the goal of refining future therapeutic strategies. Maintaining calcium equilibrium is thus essential for the advancement of effective treatments in both cancer and infectious disease contexts.

Wnt/B-catenin activation and TP53 mutations associate with distinct immune profiles in advanced thyroid cancer.

Anaplastic thyroid carcinomas (ATCs) and poorly differentiated thyroid carcinomas (PDTCs) exhibit distinct immune-related gene expression profiles. Most ATCs are characterized by active immune interactions (hot or altered immunosuppressed immunophenotypes), while PDTCs are largely immunologically inert (cold immunophenotypes). This study aimed to elucidate the mechanisms driving these divergent immunological fates, focusing on the Wnt/β-catenin pathway and TP53 mutations. Our data reveal that ATCs frequently harbor TP53 mutations (83.3%), which correlate with a hot immunophenotype, characterized by high expression of β-catenin-regulated cytokine CCL4 and recruitment of CD103+ dendritic cells. Conversely, PDTCs, with a lower incidence of TP53 mutations (12.5%), often exhibit a cold immunophenotype. In cold cancers and PDTCs, β-catenin is overexpressed suggesting that Wnt/β-catenin pathway activation drives immune exclusion through CCL4 downregulation.Further analysis indicated that loss of p53 function is inversely correlated with β-catenin expression. P53-mutated cancers showed significantly higher expression of CCL4 and densities of CD103+ dendritic cells compared to their p53-wild-type counterparts. Additionally, p53-mutated ATCs expressed a higher number of immune-related genes, supporting the role of p53 loss in activating immune responses in cancer. Our study indicates a potential correlation between the activation of the Wnt/β-catenin pathway and the development of cold thyroid cancers, which may be mediated by the suppression of CCL4 expression. Concurrently, mutations in the p53 gene appear to be linked with the occurrence of hot thyroid cancers. While these associations are compelling, they are based on observational data. Experimental research is necessary to determine the causal relationships underlying these findings.

Chitinase 3-like-1 Inhibits Innate Antitumor and Tissue Remodeling Immune Responses by Regulating CD47-SIRPα- and CD24-Siglec10-Mediated Phagocytosis.

Innate immune responses such as phagocytosis are critically linked to the generation of adaptive immune responses against the neoantigens in cancer and the efferocytosis that is essential for homeostasis in diseases characterized by lung injury, inflammation, and remodeling as in chronic obstructive pulmonary disease (COPD). Chitinase 3-like-1 (CHI3L1) is induced in many cancers where it inhibits adaptive immune responses by stimulating immune checkpoint molecules (ICPs) and portends a poor prognosis. CHI3L1 is also induced in COPD where it regulates epithelial cell death. In this study, we demonstrate that pulmonary melanoma metastasis inhibits macrophage phagocytosis by stimulating the CD47-SIRPα and CD24-Siglec10 phagocytosis checkpoint pathways while inhibiting macrophage "eat me" signals from calreticulin and HMGB1. We also demonstrate that these effects on macrophage phagocytosis are associated with CHI3L1 stimulation of the SHP-1 and SHP-2 phosphatases and inhibition of the accumulation and phosphorylation of cytoskeleton-regulating nonmuscle myosin IIa. This inhibition of innate immune responses such as phagocytosis provides a mechanistic explanation for the ability of CHI3L1 to stimulate ICPs and inhibit adaptive immune responses in cancer and diseases such as COPD. The ability of CHI3L1 to simultaneously inhibit innate immune responses, stimulate ICPs, inhibit T cell costimulation, and regulate a number of other oncogenic and inflammation pathways suggests that CHI3L1-targeted therapeutics are promising interventions in cancer, COPD, and other disorders.

Non-Coding RNAs and Innate Immune Responses in Cancer.

Non-coding RNAs (ncRNAs) and the innate immune system are closely related, acting as defense mechanisms and regulating gene expression and innate immunity. Both are modulators in the initiation, development and progression of cancer. We aimed to review the major types of ncRNAs, including small interfering RNAs (siRNAs), microRNAs (miRNAs), piwi-interacting RNAs (piRNAs), and long non-coding RNAs (lncRNAs), with a focus on cancer, innate immunity, and inflammation. We found that ncRNAs are closely related to innate immunity, epigenetics, chronic inflammation, and cancer and share properties such as inducibility, specificity, memory, and transfer. These similarities and interrelationships suggest that ncRNAs and modulators of trained immunity, together with the control of chronic inflammation, can be combined to develop novel therapeutic approaches for personalized cancer treatment. In conclusion, the close relationship between ncRNAs, the innate immune system, and inflammation highlights their importance in cancer pathways and their potential as targets for novel therapeutic strategies.

Regulatory T cells: masterminds of immune equilibrium and future therapeutic innovations.

Regulatory T cells (Tregs), a subset of CD4+T cells marked by the expression of the transcription factor forkhead box protein 3 (Foxp3), are pivotal in maintaining immune equilibrium and preventing autoimmunity. In our review, we addressed the functional distinctions between Foxp3+Tregs and other T cells, highlighting their roles in autoimmune diseases and cancer. We uncovered the dual nature of Tregs: they prevented autoimmune diseases by maintaining self-tolerance while contributing to tumor evasion by suppressing anti-tumor immunity. This study underscored the potential for targeted therapeutic strategies, such as enhancing Treg activity to restore balance in autoimmune diseases or depleting Foxp3+Tregs to augment anti-tumor immune responses in cancer. These insights laid the groundwork for future research and clinical applications, emphasizing the critical role of Foxp3+Tregs in immune regulation and the advancement of next-generation immunotherapies.

Pan-cancer analysis identifies venous thromboembolism-related genes F3, PLAT, and C1S as potential prognostic biomarkers for glioblastoma and lower grade glioma

Venous thromboembolism (VTE) is a prevalent complication among patients with cancer, contributing significantly to morbidity and mortality. However, the relationship between VTE-related genes (VRGs) and their potential impact on prognosis, immune response, and therapeutic targets in various cancer types remains unclear. Based on the coagulation and complement pathways, we identified hub VRGs that play a role in regulating the immune response in cancer. Specifically, coagulation factor III (F3), plasminogen activator (PLAT) and complement C1s (C1S) were identified as genes that exhibit high expression levels, positively correlating with tumor stemness and copy number variations, while inversely correlating with methylation levels, in particular cancer types. Pan-cancer survival analysis revealed detrimental effects of these VRGs in several cancer types, notably in glioblastoma and lower grade glioma (GMBLGG). Further analysis using receiver operating characteristic (ROC) curves demonstrated a high accuracy of F3, PLAT and C1S in predicting outcomes in GBMLGG, with area under the curve (AUC) values ranging from 0.78 to 0.9. Validation of the prognostic value of these three genes in GMBLGG was conducted using an independent Gene Expression Omnibus (GEO) dataset. Additionally, gene–drug association analysis identified ciclosporin, ouabain and 6- mercaptopurine, which all exhibit immunosuppressive properties, as potential therapeutic options for tumor patients exhibiting high F3, PLAT or C1S expression, respectively. In summary, our findings provide a bioinformatics perspective on VRGs in pan-cancer, highlighting the pivotal roles of F3, PLAT and C1S, which could potentially be therapeutically exploited and targeted in several cancers, especially in GBMLGG.

Characterization of an expanded set of assays for immunomodulatory proteins using targeted mass spectrometry

Immunotherapies are revolutionizing cancer care, but many patients do not achieve durable responses and immune-related adverse events are difficult to predict. Quantifying the hundreds of proteins involved in cancer immunity has the potential to provide biomarkers to monitor and predict tumor response. We previously developed robust, multiplexed quantitative assays for immunomodulatory proteins using targeted mass spectrometry, providing measurements that can be performed reproducibly and harmonized across laboratories. Here, we expand upon those efforts in presenting data from a multiplexed immuno-oncology (IO)-3 assay panel targeting 43 peptides representing 39 immune- and inflammation-related proteins. A suite of novel monoclonal antibodies was generated as assay reagents, and the fully characterized antibodies are made available as a resource to the community. The publicly available dataset contains complete characterization of the assay performance, as well as the mass spectrometer parameters and reagent information necessary for implementation of the assay. Quantification of the proteins will provide benefit to correlative studies in clinical trials, identification of new biomarkers, and improve understanding of the immune response in cancer.

Structural Modifications of Covalent Cathepsin S Inhibitors: Impact on Affinity, Selectivity, and Permeability.

Cathepsin S (catS) is a member of the cysteine protease family with limited tissue distribution, which is predominantly found in antigen-presenting cells. Due to overexpression and overactivity of catS in numerous cancers, inhibition of catS is supposed to improve the antitumor response. Here, we explore the potential of small-molecule catS inhibitors emphasizing their in vitro pharmacodynamics and pharmacokinetics. Membrane permeability of selected inhibitors was measured with a Parallel Artificial Membrane Permeation Assay and correlated to calculated physicochemical parameters and inhibition data. The binding kinetics and inhibition types of potent and selective new inhibitors with unexplored warheads were investigated. Our unique approach involves reversible masking of these potent warheads, allowing for further customization without compromising affinity or selectivity. The most promising inhibitors in this study include covalent aldehyde and ketone derivatives reversibly masked as hydrazones as potential candidates for therapeutic interventions targeting catalytic enzymes and modulating the immune response in cancer.

Multifaceted roles of PD-1 in tumorigenesis: From immune checkpoint to tumor cell-intrinsic function.

Programmed cell death 1 (PD-1), a key immune checkpoint receptor, has been extensively studied for its role in regulating immune responses in cancer. However, recent research has unveiled a complex and dual role for PD-1 in tumorigenesis. While PD-1 is traditionally associated with immune cells, this article explores its expression in various cancer cells and its impact on cancer progression. PD-1's functions extend beyond immune regulation, as it has been found to both promote and suppress tumor growth, depending on the cancer type. These findings have significant implications for the future of cancer treatment and our understanding of the immune response in the context of cancer. This article calls for further research into the multifaceted roles of PD-1 to optimize its therapeutic potential and improve patient outcomes in the fight against cancer.

CRISPR/Cas9 screen reveals that targeting TRIM34 enhances ferroptosis sensitivity and augments immunotherapy efficacy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent malignancy characterized by complex heterogeneity and drug resistance. Resistance to ferroptosis is closely related to the progression of HCC. While HCC tumors vary in their sensitivity to ferroptosis, the precise factors underlying this heterogeneity remain unclear. In this study, we sought to elucidate the mechanisms that contribute to ferroptosis resistance in HCC. Whole-genome CRISPR/Cas9 screen using a subtoxic concentration (IC20) of ferroptosis inducer erastin in the HCC cell line Huh7 revealed TRIM34 as a critical driver of ferroptosis resistance in HCC. Further investigation revealed that TRIM34 suppresses ferroptosis in HCC cells, promoting their proliferation, migration, and invasion both in vitro and in vivo. Furthermore, TRIM34 expression is elevated in HCC tumor tissues, correlating with a poor prognosis. Mechanistically, TRIM34 directly interacts with Up-frameshift 1 (UPF1), a core component of the nonsense-mediated mRNA decay (NMD) pathway, to promote its ubiquitination and degradation. This interaction suppresses GPX4 transcript degradation, thus promoting the protein levels of this critical ferroptosis suppressor in HCC. In light of the close crosstalk between ferroptosis and the adaptive immune response in cancer, HCC cells with targeting knockdown of TRIM34 exhibited an improved response to anti-PD-1 treatment. Taken together, the TRIM34/UPF1/GPX4 axis mediates ferroptosis resistance in HCC, thereby promoting malignant phenotypes. Targeting TRIM34 may thus represent a promising new strategy for HCC treatment.

Prognostic effect of TCF1+ CD8+ T cell and TOX+ CD8+ T cell infiltration in lung adenocarcinoma.

Recent studies have highlighted the pivotal roles of T cell transcription factors TCF-1 and TOX in modulating the immune response in cancer, with TCF-1 maintaining CD8+ T cell stemness and TOX promoting T cell exhaustion. The prognostic significance of these factors in lung adenocarcinoma (LUAD) remains a critical area of investigation. The retrospective study included 191 patients with LUAD who underwent surgery, of whom 83% were in stages II and III. These patients were divided into exploratory (n = 135) and validation (n = 56) groups based on the time of diagnosis. Multiplex fluorescence immunohistochemistry was used to examine the infiltration levels of CD8+ T cells, TCF1+ CD8+ T cells, and TOX+ CD8+ T cells. The percentage of CD8+ T cells in tumor was markedly lower than that in stroma (p < 0.05). In tumor-draining lymph nodes (TDLNs) invaded by tumor, the proportion of stem-like TCF1+ CD8+ T cells was significantly decreased (p < 0.01). Importantly, higher infiltration levels of CD8+ T cells and TCF1+ CD8+ T cells were associated with improved disease-free survival (DFS) (p = 0.009 and p = 0.006, respectively) and overall survival (OS) (p = 0.018 and p = 0.010, respectively). This study underscores the potential of TCF1+ CD8+ T cells as prognostic biomarkers in LUAD, providing insights into the tumor immune microenvironment and guiding future therapeutic strategies.

Abstract 4514: Discovery of potent and orally bioavailable degraders of HPK1 based on a novel HPK1 binder

Abstract Background: Proteolysis targeting chimeras (PROTACs) are novel structures designed to target a protein of interest (POI) for ubiquitination and degradation, leading to the selective reduction in the expression levels of the POI. Hematopoietic progenitor kinase 1 (HPK1) is considered a promising target for tumor immunotherapy. PROTAC-involved disruption of HPK1 protein activity enhanced the treatment efficacy of CAR-T-cell-based immunotherapies in different solid tumors and mouse models. Thus, targeting HPK1 by PROTAC to restore T-cell activity is an attractive approach to induce a greater immune responses in cancer. Results: We designed and synthesized a series of HPK1 degraders by tethering our previously discovered novel HPK1 inhibitor with CRBN binder through various linkage. The most potent PROTAC effectively degrades HPK1 proteins in the Ramous cell in a dose-dependent manner and achieves DC50 value &amp;lt;50 nM. The maximum degradation (D max ) values achieved are &amp;gt;90%. Our PROTAC showed EC50 value &amp;lt;100 nM for IL-2 and IFNγ production. PK studies revealed a low clearance, high plasma exposure and oral bioavailability in mice and rats. Furthermore, our PROTAC is shown to induce robust and statistically significant tumor growth inhibition in the MC38 and CT26 syngeneic model with increased T cell signatures observed within the tumor. The PROTAC in combination with anti-PD1 also resulted in robust anti-tumor activity with TGI &amp;gt; 90%. The 14 days DRF experiment shows that the compound has a great safety window(&amp;gt;200 folds). Conclusion: We show here that a potent oral HPK1 degrader demonstrates strong immune cell activation and robust anti-tumor activity in mouse syngeneic tumor models, as a single agent and in combination with anti-PD1. Further evaluation of these potent degraders in additional in vivo studies will continue to build upon our mechanistic understanding of HPK1 degradation as a novel immunomodulatory approach for anti-tumor immunity. Citation Format: Zhimin Zhang, Mengqiang Wu, Ling Wang, Xi Yang, Zhiping Zhang, Liubin Guo, Hao Pan, Mengting Zhao, Linli Wang, Sirui Liu, Zhao Dong, Chunhua Jiang, Haowen Zheng, Dongzhou Liu. Discovery of potent and orally bioavailable degraders of HPK1 based on a novel HPK1 binder [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4514.

Abstract 7517: Integrating in situ proximity ligation assay for PD1-PDL1 interaction with multiplexed immunofluorescence imaging

Abstract Background: Programmed cell death protein 1 (PD1) and its ligand PD-L1 are pivotal components of the immune checkpoint machinery, playing a crucial role in the regulation of immune responses in cancer. The interaction between PD1 and PD-L1 is a significant therapeutic target in oncology, as its inhibitors have shown improved outcomes across a variety of malignancies. However, the treatment response to immunotherapies such as pembrolizumab has shown a modest response (~30%) in previous studies. This could be explained by the lack of molecular insight pertaining to the interaction of PD1 on T-cells and PD-L1 in the tumor cells in malignant tissues at the time of clinical diagnosis. The recent development of in situ Proximity Ligation Assay (isPLA), marks a significant advancement in the field. This method allows for the visualization of direct protein interactions within tissues, for example between PD1 and PD-L1. This adds an important layer of information compared to multiplexed immunofluorescence, which is useful for deep phenotyping of cell types in a tissue but lacks the ability to detect direct interactions between specific cells. Methods: PD-L1-PD1 interactions in human FFPE tonsil and bladder cancer tissue were identified using the NaveniFlex Tissue Atto647N kit, following the guidelines provided by the manufacturer. This method is capable of detecting proteins within a proximity of less than 40 nm, utilizing oligonucleotide-antibody conjugates that generate an enhanced fluorescent signal. After completing the Naveni® detection process, we performed multiplexed immunofluorescence (IF) using the Phenocycler platform and a panel of 14 barcoded antibodies, to generate isPLA and multiplexed IF data on the same tissue section. Results &amp; Discussion: We have successfully established an automated workflow for the isPLA protocol. In this work, we aim to continue this effort and combine the isPLA, with downstream highly multiplexed immunofluorescence using the Phenocycler platform. We have generated proof of concept data for the successful integration of the two methods, using tonsil and bladder cancer tissue to detect protein interactions between PD1 and PD-L1, as well as phenotypic profiling of the tumor microenvironment with a 14 plex panel. This panel allows us to phenotype the relevant cell types (B cells, dendritic cells, T cells, macrophages, tumor cells and their proliferation status) and subsets of T-cells like cytotoxic CD8+ cells. The integration of the isPLA and multiplexed IF is poised to significantly advance our understanding of the TME and hopefully aid in patient stratification for immune checkpoint inhibition therapy. The clinical significance of this method integration will later be explored in a retrospective cohort of muscle invasive bladder cancer, receiving immune checkpoint inhibition therapy with pembrolizumab as a second line treatment. Citation Format: Tony Ullman, David Krantz, Hampus Elofsson, Carolina Oses Sepulveda, Agata Zieba-Wicher, Päivi Östling, Anders Ullén, Subham Basu, Charlotte Stadler. Integrating in situ proximity ligation assay for PD1-PDL1 interaction with multiplexed immunofluorescence imaging [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7517.

Abstract B023: The role of ribosomal protein L22 in regulating the immune landscape in mismatch repair deficient endometrial cancers

Abstract The purpose of this study is to identify novel mechanisms of immune evasion in mismatch repair deficient endometrial cancers. Despite having a hypermutated phenotype that is proposed to lead to the accumulation of many neoantigens for immune recognition, our group has found that mismatch repair deficient endometrial cancers characterized by MLH1 protein loss display large variations in the number of tumors infiltrating CD8+ T cells (TILs) across different tumors. To better understand how variations in TILs arise in mismatch repair deficient endometrial cancers, we utilized human endometrial cancer samples from the UNCseq cohort. Immunohistochemistry (IHC) was used to identify expression patterns in proteins of interest across mismatch repair deficient endometrial cancers. To determine how expression patterns of proteins of interest correlate with TILs in our patient samples, Definiens Tissue Studio was utilized to quantify immunofluorescent CD8+ TILs in our mismatch repair deficient endometrial cancer cohort. Although upregulation of programmed death ligand 1 (PD-L1) expression is often cited as an explanation for low TILs, analysis of human data by our group shows that PD-L1 expression does not correlate with TIL numbers in mismatch repair deficient endometrial cancers. Interestingly, The Cancer Genome Atlas (TCGA) data reported that ribosomal protein L22 (RPL22) is mutated in ~50% of mismatch repair deficient endometrial cancers. We analyzed RPL22 by IHC and found that it was lost in 52% of our human mismatch repair deficient endometrial cancer cohort. Loss of various ribosomal proteins can alter translation efficiency of proteins critical for promoting immunosurveillance and the immune response in cancer. In our cohort, mismatch repair deficient endometrial cancers that have lost expression of RPL22 have lower numbers of CD8+ TILs. Preliminary data also show that human endometrial cancer cell lines that do not express RPL22 also do not express beta-2-microglobulin (β2M), a component of the major histocompatibility complex I (MHC-I) molecules that is necessary for neoantigen presentation to CD8+ T cells. Thus, we hypothesize that RPL22 loss in mismatch repair deficient endometrial cancers results in decreased translation of β2M and CD8+ T cell evasion. Moving forward, we speculate that RPL22 could be utilized as a predictive biomarker for immunotherapy response in mismatch repair deficient endometrial cancers. Citation Format: Macy L. Osborne, Hannah Atkins, Andrew B. Gladden, Russell R. Broaddus. The role of ribosomal protein L22 in regulating the immune landscape in mismatch repair deficient endometrial cancers [abstract]. In: Proceedings of the AACR Special Conference on Endometrial Cancer: Transforming Care through Science; 2023 Nov 16-18; Boston, Massachusetts. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(5_Suppl):Abstract nr B023.

Lysosomal processing of sulfatide analogs alters target NKT cell specificity and immune responses in cancer.

In a structure-function study of sulfatides that typically stimulate type II NKT cells, we made an unexpected discovery. We compared analogs with sphingosine or phytosphingosine chains and 24-carbon acyl chains with 0-1-2 double bonds (C or pC24:0, 24:1, or 24:2). C24:1 and C24:2 sulfatide presented by the CD1d monomer on plastic stimulated type II, not type I, NKT cell hybridomas, as expected. Unexpectedly, when presented by bone marrow-derived DCs (BMDCs), C24:2 reversed specificity to stimulate type I, not type II, NKT cell hybridomas, mimicking the corresponding β-galactosylceramide (βGalCer) without sulfate. C24:2 induced IFN-γ-dependent immunoprotection against CT26 colon cancer lung metastases, skewed the cytokine profile, and activated conventional DC subset 1 cells (cDC1s). This was abrogated by blocking lysosomal processing with bafilomycin A1, or by sulfite blocking of arylsulfatase or deletion of this enyzme that cleaves off sulfate. Thus, C24:2 was unexpectedly processed in BMDCs from a type II to a type I NKT cell-stimulating ligand, promoting tumor immunity. We believe this is the first discovery showing that antigen processing of glycosylceramides alters the specificity for the target cell, reversing the glycolipid's function from stimulating type II NKT cells to stimulating type I NKT cells, thereby introducing protective functional activity in cancer. We also believe our study uncovers a new role for antigen processing that does not involve MHC loading but rather alteration of which type of cell is responding.

Immune Assessment Today: Optimizing and Standardizing Efforts to Monitor Immune Responses in Cancer and Beyond.

As part of a symposium, current and former directors of Immune Monitoring cores and investigative oncologists presented insights into the past, present and future of immune assessment. Dr. Gnjatic presented a classification of immune monitoring technologies ranging from universally applicable to experimental protocols, while emphasizing the need for assay harmonization. Dr. Obeng discussed physiologic differences among CD8 T cells that align with anti-tumor responses. Dr. Lyerly presented the Soldano Ferrone lecture, commemorating the passionate tumor immunologist who inspired many, and covered a timeline of monitoring technology development and its importance to immuno-oncology. Dr. Sonabend presented recent achievements in glioblastoma treatment, accentuating the range of monitoring techniques that allowed him to refine patient selection for clinical trials. Dr. Guevara-Patiño focused on hypoxia within the tumor environment and stressed that T cell viability is not to be confused with functionality. Dr. Butterfield accentuated monitoring of dendritic cell metabolic (dys)function as a determinant for tumor vaccine success. Lectures were interspersed with select abstract presentations. To summarize the concepts, Dr. Maecker from Stanford led an informative forum discussion, pointing towards the future of immune monitoring. Immune monitoring continues to be a guiding light towards effective immunotherapeutic strategies.

β1-Adrenergic receptor stimulation modulates immune response in cancer: a role for β-blockers in antineoplastic treatment?

β1-Adrenergic receptor stimulation modulates immune response in cancer: a role for β-blockers in antineoplastic treatment?

Potential cGAS-STING pathway functions in DNA damage responses, DNA replication and DNA repair

The major innate immune responder to the DNA of pathogens is the cyclic GMP-AMP (cGAMP) synthase (cGAS) - stimulator of interferon genes (STING) pathway. Most prominently, the outcome of cGAS signalling is the activation of inflammatory transcription through interferon regulatory factor 3 (IRF3) and nuclear factor kappa B (NF-kB). In addition, the cGAS-STING pathway can lead to the direct modulation of cellular processes independently of transcription, such as activation of autophagy. Under unperturbed conditions, several mechanisms are in place to prevent the activation of cGAS by self-DNA, chiefly its sequestration on chromatin, which interferes with binding to stimulatory DNA. However, under conditions of genotoxic stress and chromosomal instability, this inhibition breaks down, resulting in the activation of cGAS, which drives sterile inflammation, as well as cell fate and immune responses in cancer. Recently, several studies have suggested that cGAS, STING, or downstream pathway components can also regulate the DNA damage response, DNA damage checkpoint signalling, DNA repair and DNA replication. Here, I review these proposed mechanisms, and discuss some unanswered questions relating to them.

Laser-Activatable In Situ Vaccine Enhances Cancer-Immunity Cycle.

The immune response in cancer reflects a series of carefully regulated events; however, current tumor immunotherapies typically address a single key aspect to enhance anti-tumor immunity. In the present study, a nanoplatform (Fe3 O4 @IR820@CpG)-based immunotherapy strategy that targets the multiple key steps in cancer-immunity cycle is developed: 1) promotes the release of tumor-derived proteins (TDPs), including tumor-associated antigens and pro-immunostimulatory factors), in addition to the direct killing effect, by photothermal (PTT) and photodynamic therapy (PDT); 2) captures the released TDPs and delivers them, together with CpG (a Toll-like receptor 9 agonist) to antigen-presenting cells (APCs) to promote antigen presentation and T cell activation; 3) enhances the tumor-killing ability of T cells by combining with anti-programmed death ligand 1 antibody (α-PD-L1), which collectively advances the outstanding of the anti-tumor effects on colorectal, liver and breast cancers. The broad-spectrum anti-tumor activity of Fe3 O4 @IR820@CpG with α-PD-L1 demonstrates that optimally manipulating anti-cancer immunity not singly but as a group provides promising clinical strategies.