Current Immune Therapies Research Articles

Abstract 3618: High-avidity BCMA CAR and high-affinity, non-cleavable CD16 Fc receptor incorporated in off-the-shelf CAR T cells promote multi-antigen targeting and durable anti-tumor cytotoxicity in the treatment of multiple myeloma

Abstract Immune cell therapy has proven highly effective for the treatment of multiple myeloma (MM). However, key challenges remain that include disease relapse, limited patient access, and inability to effectively combine with existing standard-of-care therapies. Rapid progress in the development of off-the-shelf, multiplexed-engineered, induced pluripotent stem cell (iPSC)-derived cell therapies enables large-scale manufacture of immune cells incorporating multiple novel synthetic controls of cell function to improve cell fitness, enhance cell function, and enable synergistic combination with existing effective therapies such as CD38-targeted antibody (mAb) therapy. We have developed an iPSC-derived chimeric antigen receptor T (CAR-iT) cell therapy that uniquely leverages elements of both adaptive and innate immunity by incorporating a BCMA-targeted CAR (BCMA-CAR) derived from a scFv domain exhibiting high-binding affinity in the low nanomolar range, and a high-affinity, non-cleavable CD16 (hnCD16) Fc receptor to enable antibody-dependent cellular cytotoxicity with mAb therapy. The genetic deletion of CD38 gene was also incorporated to eliminate the possibility for CD38-mediated fratricide, and genetic deletion of TRAC gene was introduced to remove the potential risk of graft-versus-host disease in an allogeneic setting. These CAR iT cells, which were generated from a clonally-derived iPSC line, demonstrated homogenous expression of each genetic edit (>95% BCMA-CAR and hnCD16; <1% CD38 and TCR surface expression). Using a stringent, disseminated xenograft mouse model of multiple myeloma, MM.1S, which was allowed to achieve complete systemic engraftment during the initial 4 days, treatment with BCMA-CAR iT cells demonstrated comparable tumor cell clearance (p=0.0024 vs. vehicle at Day 17) to primary BCMA-CAR T cells (p=0.002 vs. vehicle). In combination with a CD38-targeted mAb to exploit hnCD16 and biallelic CD38 KO, BCMA-CAR iT cells are capable of dual-antigen targeting to address antigen escape and promote durable tumor control. To this end, a single dose of BCMA-CAR iT cells combined with daratumumab exhibited near complete TGI for the duration of the study (p<0.0001 vs. vehicle at Day 37). Together, these studies demonstrate CAR iT cells incorporating a high-avidity BCMA CAR and high-affinity, non-cleavable CD16 Fc receptor can uniquely leverage elements of both adaptive and innate immunity and can be combined with CD38-targeted mAb to potentially outcompete primary BCMA CAR T cells. As these CAR iT cells can be administered off-the-shelf, key challenges associated with current immune cell therapy, such as patient access and inability to synergize with standard-of-care therapies, can be addressed for the treatment of relapsed/refractory MM. Citation Format: John Reiser, Alison O'Connor, Bryan Hancock, Spas Markov, Brian Groff, Alma Gutierrez, Miguel Meza, Mark Jelcik, Yijia Pan, Alex Garcia, Bobby Goulding, Matthew Denholtz, Tom Lee, Ramzey Abujarour, Ryan Bjordahl, Armin Rehm, Raedun Clarke, Jode Goodridge, Bahram Valamehr. High-avidity BCMA CAR and high-affinity, non-cleavable CD16 Fc receptor incorporated in off-the-shelf CAR T cells promote multi-antigen targeting and durable anti-tumor cytotoxicity in the treatment of multiple myeloma [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 3618.

Aqueous Macrophages Contribute to Conserved CCL2 and CXCL10 Gradients in Uveitis

Uveitis is a heterogenous group of inflammatory eye disease for which current cytokine-targeted immune therapies are effective for only a subset of patients. We hypothesized that despite pathophysiologic nuances that differentiate individual disease states, all forms of eye inflammation might share common mechanisms for immune cell recruitment. Identifying these mechanisms is critical for developing novel, broadly acting therapeutic strategies. Experimental study. Biospecimens from patients with active or inactive uveitis and healthy controls. Protein concentration and single cell gene expression were assessed in aqueous fluid biopsies and plasma samples from deidentified patients with uveitis or healthy controls. The concentration of 31 inflammatory proteins was measured in all aqueous samples, as well as plasma samples from patients with active uveitis. Chemokine and cytokine ligand and receptor expression were assessed in individual cell types from aqueous biopsies obtained from patients with active uveitis. We identified 6 chemokines that were both elevated in active uveitis compared with controls and enriched in aqueous compared with plasma during active uveitis (C-C motif chemokine ligand [CCL]2, C-X-C motif chemokine ligand [CXCL]10, CXCL9, CXCL8, CCL3, and CCL14), forming potential gradients for migration of immune cells from the blood to the eye. Of these, CCL2 and CXCL10 were consistently enriched in the aqueous of all patients in our cohort, as well as in a larger cohort of patients from a previously published study. These data suggest that CCL2 and CXCL10 are key mediators in immune cell migration to the eye during uveitis. Next, single cell RNA sequencing suggested that macrophages contribute to aqueous enrichment of CCL2 and CXCL10 during human uveitis. Finally, using chemokine ligand and receptor expression mapping, we identified a broad signaling network for macrophage-derived CCL2 and CXCL10 in human uveitis. These data suggest that ocular macrophages may play a central role, via CCL2 and CXCL10 production, in recruiting inflammatory cells to the eye in patients with uveitis. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Tumor-intrinsic RGS1 potentiates checkpoint blockade response via ATF3-IFNGR1 axis

ABSTRACT Background Non-responsiveness is a major barrier in current cancer immune checkpoint blockade therapies, and the mechanism has not been elucidated yet. Therefore, it is necessary to discover the mechanism and biomarkers of tumor immunotherapeutic resistance. Methods Bioinformatics analysis was performed based on CD8+ T cell infiltration in multiple tumor databases to screen out genes related to anti-tumor immunity. Associations between Regulator of G-protein signaling 1 (RGS1) and IFNγ-STAT1 signaling, and MHCI antigen presentation pathway were examined by RT-qPCR, western blotting, and flow cytometry. The modulatory mechanisms of RGS1 were investigated via CHIP-qPCR and dual-luciferase assay. The clinical and therapeutic implications of RGS1 were comprehensively investigated using tumor cell lines, mouse models, and clinical samples receiving immunotherapy. Results RGS1 was identified as the highest gene positively correlated with immunogenicity among RGS family. Inhibition of RGS1 in neoplastic cells dampened anti-tumor immune response and elicited resistance to immunotherapy in both renal and lung murine subcutaneous tumors. Mechanistically, RGS1 enhanced the binding of activating transcription factor 3 (ATF3) to the promoter of interferon gamma receptor 1 (IFNGR1), activated STAT1 and the subsequent expression of IFNγ-inducible genes, especially CXCL9 and MHC class I (MHCI), thereby influenced CD8+ T cell infiltration and antigen presentation and processing. Clinically, lower expression level of RGS1 was associated with resistance of PD1 inhibition therapy and shortened progression-free survival among 21 NSCLC patients receiving immunotherapy. Conclusions Together, these findings uncover a novel mechanism that elicits immunotherapy resistance and highlight the function of tumor-intrinsic RGS1, which brings new insights for future strategies to sensitize anti-PD1 immunotherapy.

Immune-based therapies in diffuse large B-cell lymphoma

ABSTRACT Introduction Diffuse large B-cell lymphoma (DLBCL) is an aggressive and clinically heterogeneous malignancy originating from B-cells with up to 40% of patients experiencing primary refractory disease or relapse after first-line treatment. However, the past 5 years have seen a flurry of new drug approvals for DLBCL anchored upon new immune therapies, including chimeric antigen receptor (CAR) T-cells and antibody-based therapies. Areas covered This article summarizes recent advances in the treatment of DLBCL, including in the first line and relapsed and refractory setting (second-line and beyond). A literature search was conducted for publications relevant to the immunotherapeutic approach to DLBCL from 2000 through March 2023 within PubMed and articles were reviewed. The search terms were immunotherapy, monoclonal antibodies, chimeric antigen receptor modified T-cell (CAR-T), and classification of DLBCL. Relevant clinical trials and pre-clinical studies exploring the strengths and weaknesses of current immune therapies against DLBCL were chosen. We additionally explored how intrinsic differences amongst DLBCL subtype biology and endogenous host immune recruitment contribute to variable therapeutic efficacy. Expert Opinion Future treatments will minimize chemotherapy exposure and be chosen by underlying tumor biology, paving the way for the promise of chemotherapeutic free regimens and improved outcomes for poor-risk subgroups.

Abstract 4263: Anti-Siglec 7 antibody displays potent anti-tumor immunity and demonstrates improved tumor control in combination with anti-PD1 in ovarian cancer

Abstract High grade serous ovarian cancer (OC) and ovarian carcinosarcoma, referred as “Cold” tumors have restricted treatment choices and being associated with high mortality. Current immune checkpoint inhibitors (CPIs) have had modest impact for OC treatment; with anti PD-1/PD-L1 single therapies reported response rates of 4-15%. Accordingly, additional approaches are important for these patients. Natural killer (NK) cells represent an important subset of effector lymphocytes with strategic approaches for maximizing NK reactivity to target OC are likely important. Of interest, an inhibitory receptor and glyco immune checkpoint- Siglec 7 is expressed on 100% of peripheral blood and umbilical cord NK cells. We have generated antibodies against Siglec 7 through an optimized human Siglec 7 DNA/protein immunization approach in humanized next generation transgenic mice. By high throughput flow screening, we identified several Siglec 7 antibodies and down selected relevant clones. A unique clone DB7.2 was highly specific for Siglec 7. We demonstrated the ability of DB7.2 (human IgG1) to activate NK cells and induce OC cell killing using xCELLigence RTCA for in vivo OC challenge studies. DB7.2 (1μg/ml) bound to >90% of NK cells including both CD56dim and CD56bright subsets, evaluated in the PBMCs of multiple donors. It showed strong binding to recombinant Siglec 7 and Siglec 7 transduced HEK293T but not to wild type 293T cells supporting specificity. DB7.2 induced specific killing of multiple OC lines (OVCAR3&10,TOV21G, CaOV3, OVISE, PEO4) carrying different mutations; BRCA1&2, AKT, TP53, PIK3CA, BRAF etc. and resistant against a wide array of cancer drug targets; HSP90, HDAC, MTORC, DNA alkylating agents, EGFR, PARP, PI3K, and WEE1. Tumor killing was indicated to be mediated via enhanced secretion of soluble Fas, perforin, granulysin as well as granzyme A. Of note, OVISE (BRCA1mutated) and PEO4 (BRCA2 mutated, PARPi resistant) were susceptible to DB7.2 killing with EC50- 82.67 and 68.67 nM respectively. A single dose of in vivo expressed DB7.2 significantly reduced the tumor burden in an OVISE challenged humanized mice model enhancing median survival by 57 days. As OCs are highly diverse in nature and likely to require combinatorial approaches for simultaneous targeting of immune pathways; we combined DB7.2 with anti-PD1 for further investigation. In xCELLigence assay, anti-PD1 demonstrated killing of PEO4 cells with EC50 680 nM. The combination of anti PD-1 with DB7.2 showed further enhancement of OC killing in the presence of human PBMCs. This is the first demonstration of the impact of Siglec 7 targeting mAb alone as well as in combination with anti-PD1 (NK and T cell CPIs) studied for targeting OC or any human tumor. These studies have important implications for tumor therapy and provide a novel non T cell CPI potential approach to augment current immune therapy strategies. Citation Format: Devivasha Bordoloi, Abhijeet J. Kulkarni, Opeyemi S. Adeniji, M Betina Pampena, Pratik S. Bhojnagarwala, Shushu Zhao, Elizabeth M. Parzych, Rugang Zhang, Michael R. Betts, Mohamed Abdel-Mohsen, David B. Weiner. Anti-Siglec 7 antibody displays potent anti-tumor immunity and demonstrates improved tumor control in combination with anti-PD1 in ovarian cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4263.

342 The Implications of High Expression of VISTA, a Negative Check Point Regulator, on Prognosis Across Malignant Solid Tumors: a Systematic Review and Meta-Analysis

OBJECTIVES/GOALS: Targeting the V-domain immunoglobulin suppressor of T cell activation (VISTA) signaling pathway has been suggested as a promising approach for overcoming resistance to current immune checkpoint therapies in advanced cancer. This review will synthesize the rapidly-expanding literature on VISTA protein expression on prognosis in various cancers. METHODS/STUDY POPULATION: To determine the prognostic significance of high VISTA expression across treatment-naïve malignant tumors, a systematic review and meta-analysis will be performed of published cohort studies which measured VISTA protein expression on solid tumors. Primary and secondary outcome endpoints of overall survival (OS) and disease-specific survival (DSS) will be compared across cohort studies using a random effects model to calculate pooled hazard ratios (HRs) for each time-to-event end point with 95% CIs. For articles that only provide Kaplan-Meier (KM) curves, the Engauge Digitizer software will be used to measure the time and survival probability coordinates on the KM curves to estimate the HRs. Correlations of VISTA expression and clinicopathological characteristics will be evaluated by pooled risk ratios. RESULTS/ANTICIPATED RESULTS: A search of 4 electronic databases including Pubmed, Embase, Web of Science and Cochrane resulted in 5578 publications of which 66 containing a broad spectrum of malignant solid tumors will undergo full-text review for study inclusion. Tumor types most represented with at least 3 articles include lung, pancreas, skin, head & neck, colorectal, mesothelioma, cervix, soft tissue, breast, liver and ovarian. Our working hypothesis is that the pooled HR for high VISTA expression on overall survival will be approaching 1.0 given conflicting reports across the cancer literature. Risk of bias will be assessed across studies. Quantifications of heterogeneity will be assessed by visual exploration of forest plots as well as by multiple statistical metrics including the Q statistic and the I²coefficient. DISCUSSION/SIGNIFICANCE: The results of this systematic review and meta-analysis will provide a more comprehensive understanding of VISTA’s prognostic role both across all malignant tumors and for subgroups of similar tumor types which may impact the types of tumors and tumor microenvironments selected for early trials of anti-VISTA therapy.

In-situ clickable prodrug nanoplatform locally activates T lymphocytes to potentiate cancer immunotherapy

The immune-excluded tumors (IETs) respond marginally to current immune blockade therapy due to the presence of pathophysiological barriers to restrict intratumoral infiltration of the cytotoxic T lymphocytes (CTLs). In this study, to improve the immunotherapy of the IETs, we proposed an in-situ clickable prodrug nanoplatform composed of two sets of acidity-activatable nanoparticles (NPs) for combinatory treatment. The first set of the NPs, namely precursor NPs, could be activated with the extracellular tumor acidity to label tumor extracellular milieu with dibenzocyclooctyne (DBCO) and indocyanine green, which performed florescence imaging-guided photothermal ablation of the extracellular matrix, thereby recruiting the tumor-infiltrating CTLs. The second set of NPs (i.e., the secondary NPs) were functionalized with azide groups, and specifically accumulated at the tumor site via bioorthogonal click reaction with DBCO. The secondary NPs were deshelled with matrix metalloproteinase-2 and activated in the endocytic acidic microenvironment for intracellular release of the BRD4 inhibitor JQ1. Sequential administration of the precursor and the secondary NPs, effectively promoted intratumoral infiltration of CTLs, suppressed PD-L1 upregulation, and was effective for regression 4T1 breast tumor growth, a model of the IETs. This study utilizing the tumor microenvironment-activatable in-situ click chemistry might provide an unprecedented modality to potentiate immunotherapy of the IETs.

A narrative review of immune checkpoint mechanisms and current immune checkpoint therapy

A narrative review of immune checkpoint mechanisms and current immune checkpoint therapy

Latent autoimmune diabetes in adults: a focus on β-cell protection and therapy.

Latent autoimmune diabetes in adults (LADA) is a heterogeneous disease sharing some phenotypic, genetic, and immunological features with both type 1 and 2 diabetes. Patients with LADA have a relatively slow autoimmune process and more residual islet β-cell function at onset, allowing a time window to protect residual islet β cells and delay or inhibit disease progression. It is crucial to discover various heterogeneous factors affecting islet β-cell function for precise LADA therapy. In this review, we first describe the natural history of LADA. Thereafter, we summarize β-cell function-related heterogeneous factors in LADA, including the age of onset, body mass index, genetic background, and immune, lifestyle, and environmental factors. In parallel, we evaluate the impact of current hypoglycemic agents and immune intervention therapies for islet β-cell protection. Finally, we discuss the opportunities and challenges of LADA treatment from the perspective of islet β-cell function protection.

Liver Immunology, Immunotherapy, and Liver Cancers: Time for a Rethink?

The complex immune system of the liver has a major role in tumor surveillance, but also partly explains why current immune therapies are poorly effective against liver cancers. Known primarily for its tolerogenic capacity, the hepatic immune repertoire also comprises diverse populations of armored immune cells with tumor surveillant roles. In healthy people, these work together to successfully identify malignant cells and prevent their proliferation, thus halting tumor formation. When frontline hepatic immune surveillance systems fail, compromised hepatic immunity, driven by obesity, infection, or other pathological factors, allows primary or secondary liver cancers to develop. Tumor growth promotes the normal tolerogenic immunological milieu of the liver, perhaps explaining why current immunotherapies fail to work. This review explores the complex local liver immune system with the hope of identifying potential therapeutic targets needed to best overcome immunological barriers in the liver to create an environment no longer hostile to immunotherapy for the treatment of liver cancer.

Patterns of immunological reactions in the pathogenesis of chronic heart failure: review

The immune system is essential for maintaining the homeostasis. At present, there is convincing evidence for participation of the immune system in the pathogenesis of cardiovascular pathology, including the final step of cardiovascular continuum, heart failure. Objective difficulties in understanding subtle processes of loss of the normal cardiac structure and function are based on the diversity of pathogenetic factors of development and progression of chronic heart failure (CHF) and the involvement of most organs and body systems. Russian and international scientists actively study issues of immune homeostasis, including the efficacy of current immune therapy. At the same time, available reports are largely uncompiled and reflect isolated parts of the immunopathogenesis of cardiovascular diseases. This review focuses on comprehensive elucidation of major patterns of immune processes in the CHF pathogenesis to form an integral view of the problem under study.

Characterization of m6A RNA Methylation Regulators Predicts Survival and Immunotherapy in Lung Adenocarcinoma.

N6-methyladenosine (m6A) RNA modification is a reversible mechanism that regulates eukaryotic gene expression. Growing evidence has demonstrated an association between m6A modification and tumorigenesis and response to immunotherapy. However, the overall influence of m6A regulators on the tumor microenvironment and their effect on the response to immunotherapy in lung adenocarcinoma remains to be explored. Here, we comprehensively analyzed the m6A modification patterns of 936 lung adenocarcinoma samples based on 24 m6A regulators. First, we described the features of genetic variation in these m6A regulators. Many m6A regulators were aberrantly expressed in tumors and negatively correlated with most tumor-infiltrating immune cell types. Furthermore, we identified three m6A modification patterns using a consensus clustering method. m6A cluster B was preferentially associated with a favorable prognosis and enriched in metabolism-associated pathways. In contrast, m6A cluster A was associated with the worst prognosis and was enriched in the process of DNA repair. m6A cluster C was characterized by activation of the immune system and a higher stromal cell score. Surprisingly, patients who received radiotherapy had a better prognosis than patients without radiotherapy only in the m6A cluster C group. Subsequently, we constructed an m6A score model that qualified the m6A modification level of individual samples by using principal component analysis algorithms. Patients with high m6A score were characterized by enhanced immune cell infiltration and prolonged survival time and were associated with lower tumor mutation burden and PD-1/CTLA4 expression. The combination of the m6A score and tumor mutation burden could accurately predict the prognosis of patients with lung adenocarcinoma. Furthermore, patients with high m6A score exhibited greater prognostic benefits from radiotherapy and immunotherapy. This study demonstrates that m6A modification is significantly associated with tumor microenvironment diversity and prognosis. A comprehensive evaluation of m6A modification patterns in single tumors will expand our understanding of the tumor immune landscape. In addition, our m6A score model demonstrated that the level of immune cell infiltration plays a significant role in cancer immunotherapy and provides a basis to increase the efficiency of current immune therapies and promote the clinical success of immunotherapy.

Metabolic preconditioning in CD4+ T cells restores inducible immune tolerance in lupus-prone mice.

Autoimmune disease has presented an insurmountable barrier to restoration of durable immune tolerance. Previous studies indicate that chronic therapy with metabolic inhibitors can reduce autoimmune inflammation, but it remains unknown whether acute metabolic modulation enables permanent immune tolerance to be established. In an animal model of lupus, we determined that targeting glucose metabolism with 2-deoxyglucose (2DG) and mitochondrial metabolism with metformin enables endogenous immune tolerance mechanisms to respond to tolerance induction. A 2-week course of 2DG and metformin, when combined with tolerance-inducing therapy anti-CD45RB, prevented renal deposition of autoantibodies for 6 months after initial treatment and restored tolerance induction to allografts in lupus-prone mice. The restoration of durable immune tolerance was linked to changes in T cell surface glycosylation patterns, illustrating a role for glycoregulation in immune tolerance. These findings indicate that metabolic therapy may be applied as a powerful preconditioning to reinvigorate tolerance mechanisms in autoimmune and transplant settings that resist current immune therapies.

Estrogens and the Schrödinger's Cat in the Ovarian Tumor Microenvironment.

Simple SummaryOvarian cancer is a complex pathology for which we require effective screening and therapeutical strategies. Apart from the cancer cell portion, there exist plastic immune and non-immune cell populations, jointly constituting the context-adaptive tumor microenvironment, which is pivotal in tumorigenesis. Estrogens might be synthesized in the ovarian tumor tissue and actively contribute to the shaping of an immunosuppressive microenvironment. Current immune therapies have limited effectiveness as a multitude of factors influence the outcome. A thorough understanding of the ovarian cancer biology is crucial in the efforts to reestablish homeostasis.Ovarian cancer is a heterogeneous disease affecting the aging ovary, in concert with a complex network of cells and signals, together representing the ovarian tumor microenvironment. As in the “Schrödinger’s cat” thought experiment, the context-dependent constituents of the—by the time of diagnosis—well-established tumor microenvironment may display a tumor-protective and -destructive role. Systemic and locally synthesized estrogens contribute to the formation of a pro-tumoral microenvironment that enables the sustained tumor growth, invasion and metastasis. Here we focus on the estrogen biosynthetic and metabolic pathways in ovarian cancer and elaborate their actions on phenotypically plastic, estrogen-responsive, aging immune cells of the tumor microenvironment, altogether highlighting the multicomponent-connectedness and complexity of cancer, and contributing to a broader understanding of the ovarian cancer biology.

HCG18 Participates in Vascular Invasion of Hepatocellular Carcinoma by Regulating Macrophages and Tumor Stem Cells.

ObjectivesTo identify key genes involved in vascular invasion in hepatocellular carcinoma (HCC), to describe their regulatory mechanisms, and to explore the immune microenvironment of HCC.MethodologyIn this study, the genome, transcriptome, and immune microenvironment of HCC were assessed by using multi-platform data from The Cancer Genome Atlas (n = 373) and GEO data (GSE149614). The key regulatory networks, transcription factors and core genes related to vascular invasion and prognosis were explored based on the CE mechanism. Survival analysis and gene set enrichment were used to explore pathways related to vascular invasion. Combined with single-cell transcriptome data, the distribution of core gene expression in various cells was observed. Cellular communication analysis was used to identify key cells associated with vascular invasion. Pseudo-temporal locus analysis was used to explore the regulation of core genes in key cell phenotypes. The influence of core genes on current immune checkpoint therapy was evaluated and correlations with tumor stem cell scores were explored.ResultsWe obtained a network containing 1,249 pairs of CE regulatory relationships, including 579 differential proteins, 28 non-coding RNAs, and 37 miRNAs. Three key transcription factors, ILF2, YBX1, and HMGA1, were identified, all regulated by HCG18 lncRNA. ScRNAseq showed that HCG18 co-localized with macrophages and stem cells. CIBERSORTx assessed 22 types of immune cells in HCC and found that HCG18 was positively correlated with M0 macrophages, while being negatively correlated with M1 and M2 macrophages, monocytes, and dendritic cells. Cluster analysis based on patient prognosis suggested that regulating phenotypic transformation of macrophages could be an effective intervention for treating HCC. At the same time, higher expression of HCG18, HMGA1, ILF2, and YBX1 was associated with a higher stem cell score and less tumor differentiation. Pan cancer analysis indicated that high expression of HCG18 implies high sensitivity to immune checkpoint therapy.ConclusionHCG18 participates in vascular invasion of HCC by regulating macrophages and tumor stem cells through three key transcription factors, YBX1, ILF2, and HMGA1.

MiRNAs and lncRNAs as Novel Therapeutic Targets to Improve Cancer Immunotherapy.

Simple SummaryCancer onset and progression are promoted by high deregulation of the immune system. Recently, major advances in molecular and clinical cancer immunology have been achieved, offering new agents for the treatment of common tumors, often with astonishing benefits in terms of prolonged survival and even cure. Unfortunately, most tumors are still resistant to current immune therapy approaches, and basic knowledge of the resistance mechanisms is eagerly awaited. We focused our attention on noncoding RNAs, a class of RNA that regulates many biological processes by targeting selectively crucial molecular pathways and that, recently, had their role in cancer cell immune escape and modulation of the tumor microenvironment identified, suggesting their function as promising immunotherapeutic targets. In this scenario, we point out that noncoding RNAs are progressively emerging as immunoregulators, and we depict the current information on the complex network involving the immune system and noncoding RNAs and the promising therapeutic options under investigation. Novel opportunities are emerging from noncoding-RNAs for the treatment of immune-refractory tumors.Immunotherapy is presently one of the most promising areas of investigation and development for the treatment of cancer. While immune checkpoint-blocking monoclonal antibodies and chimeric antigen receptor (CAR) T-cell-based therapy have recently provided in some cases valuable therapeutic options, the goal of cure has not yet been achieved for most malignancies and more efforts are urgently needed. Noncoding RNAs (ncRNA), including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), regulate several biological processes via selective targeting of crucial molecular signaling pathways. Recently, the key roles of miRNA and lncRNAs as regulators of the immune-response in cancer have progressively emerged, since they may act (i) by shaping the intrinsic tumor cell and microenvironment (TME) properties; (ii) by regulating angiogenesis, immune-escape, epithelial-to-mesenchymal transition, invasion, and drug resistance; and (iii) by acting as potential biomarkers for prognostic assessment and prediction of response to immunotherapy. In this review, we provide an overview on the role of ncRNAs in modulating the immune response and the TME. We discuss the potential use of ncRNAs as potential biomarkers or as targets for development or clinical translation of new therapeutics. Finally, we discuss the potential combinatory approaches based on ncRNA targeting agents and tumor immune-checkpoint inhibitor antibodies or CAR-T for the experimental treatment of human cancer.

MAL2 drives immune evasion in breast cancer by suppressing tumor antigen presentation.

Immune evasion is a pivotal event in tumor progression. To eliminate human cancer cells, current immune checkpoint therapy is set to boost CD8+ T cell-mediated cytotoxicity. However, this action is eventually dependent on the efficient recognition of tumor-specific antigens via T cell receptors. One primary mechanism by which tumor cells evade immune surveillance is to downregulate their antigen presentation. Little progress has been made toward harnessing potential therapeutic targets for enhancing antigen presentation on the tumor cell. Here, we identified MAL2 as a key player that determines the turnover of the antigen-loaded MHC-I complex and reduces the antigen presentation on tumor cells. MAL2 promotes the endocytosis of tumor antigens via direct interaction with the MHC-I complex and endosome-associated RAB proteins. In preclinical models, depletion of MAL2 in breast tumor cells profoundly enhanced the cytotoxicity of tumor-infiltrating CD8+ T cells and suppressed breast tumor growth, suggesting that MAL2 is a potential therapeutic target for breast cancer immunotherapy.

New cancer therapies. Are haematopoietic cell transplants a dead duck?

Recent therapy advances for haematological cancers including new drugs and targeted and immune therapies raise the question whether there is a future for haematopoietic cell transplants. Although encouraging, the survival improvements achieved with these new modalities in persons who might otherwise receive a transplant are modest. Furthermore, these modalities are likely to be complementary, not competitive. For example, randomised trials in multiple myeloma, the most common transplants, indicate an ongoing role for transplant despite new anti-myeloma drugs. Targeted therapies in myeloid cancers are estimated to be effective in only about 10 percent of persons with these cancers. The potential impact of current immune therapies on transplant activity is also limited because: (1) they predominately target B-cell rather than myeloid cancers; (2) many successful immune therapy recipients subsequently receive a transplant; (3) considerable data indicate much of the efficacy of allotransplants results from allogeneic rather than cancer-specific immunity not expected to operate with current immune therapies; and (4) they are at an early development stage with unknown long-term safety and efficacy. These data suggest an ongoing role for haematopoietic cell transplants in diverse haematological and genetic disorders.

Abstract IA18: Metabolic impact on cancer immunity

Abstract We have studied the crosstalk among immune cell subsets, including myeloid cells, and tumor (stem) cells in the tumor microenvironment, and its impact on tumor progression, tumor immunity, and therapy. Our research efforts demonstrate that the tumor microenvironment comprises immune cells that have been reprogrammed by active tumor-mediated processes to defeat tumor immunity and promote tumor progression in a highly effective manner. These studies, including the first demonstration of PD-L1 expression, regulation, and blockade in the human cancer microenvironment, have helped define the nature of immune responses in the cancer microenvironment, form the concept of immunosuppressive networks in the cancer microenvironment, and provide significant insights into designing current immune therapies to treat cancer patients. In this talk, I focus on cancer metabolic impact on regulatory T cells and effector T cells. (a) Regulatory T cells and oxidative stress in the cancer microenvironment: Using ovarian cancer as an example, we found that tumor Treg cells undergo apoptosis and such apoptotic Treg cells abolish spontaneous and PD-L1 blockade-mediated antitumor T-cell immunity. Biochemical and functional analyses identify that adenosine, but not typical suppressive factors such as PD-L1, CTLA4, TGF-β, IL-35, and IL-10, contributes to apoptotic Treg cell-mediated immunosuppression. Mechanistically, apoptotic Treg cells release and convert a large amount of ATP to adenosine via CD39 and CD73, and mediate immunosuppression via the adenosine and A2A pathway. Treg cell apoptosis is attributed to their weak NRF2-associated antioxidant system and high vulnerability to free oxygen species in the tumor microenvironment. Thus, the data support a model wherein tumor Treg cells sustain and amplify their suppressor capacity by inadvertent death via oxidative stress. The work highlights the oxidative pathway as a metabolic checkpoint controlling Treg cell behavior and affecting cancer checkpoint therapeutic efficacy. (b) Effector T cells and glutamate-cystine metabolism in the cancer microenvironment: In patients with ovarian cancer and melanoma, and in multiple tumor-bearing mouse models, we find that immunotherapy-activated CD8+ T cells sensitize tumor cell ferroptosis. Mechanistically, IFNg released from CD8+ T cells downregulates expression of SLC3A2 and SLC7A11, two subunits of glutamate-cystine antiporter system xc-, restrains tumor cell cystine uptake, and as a consequence, promotes tumor cell lipid peroxidation and ferroptosis. In preclinical models, depletion of cyst(e)ine by cyst(e)inase in combination with checkpoint blockade synergistically enhances T cell-mediated antitumor immunity and induces tumor cell ferroptosis. Expression of glutamate-cystine antiporter system xc- is negatively associated with CD8+ T-cell signature, IFNg expression, and cancer patient outcome. Transcriptome analyses before and during nivolumab therapy reveal that clinical benefits correlate with reduced expression of SLC3A2 and increased IFNg and CD8. Thus, T cell-promoted tumor ferroptosis is a novel antitumor mechanism. Targeting tumor ferroptosis pathway constitutes a therapeutic approach in combination with checkpoint blockade. Citation Format: Weiping Zou. Metabolic impact on cancer immunity [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr IA18.

Immunotherapy in Glioblastoma: Current Shortcomings and Future Perspectives.

Glioblastomas are aggressive, fast-growing primary brain tumors. After standard-of-care treatment with radiation in combination with temozolomide, the overall prognosis of newly diagnosed patients remains poor, with a 2-year survival rate of less than 20%. The remarkable survival benefit gained with immunotherapy in several extracranial tumor types spurred a variety of experimental intervention studies in glioblastoma patients. These ranged from immune checkpoint inhibition to vaccinations and adoptive T cell therapies. Unfortunately, almost all clinical outcomes were universally disappointing. In this perspective, we provide an overview of immune interventions performed to date in glioblastoma patients and re-evaluate their performance. We argue that shortcomings of current immune therapies in glioblastoma are related to three major determinants of resistance, namely: low immunogenicity; immune privilege of the central nervous system; and immunosuppressive micro-environment. In this perspective, we propose strategies that are guided by exact shortcomings to sensitize glioblastoma prior to treatment with therapies that enhance numbers and/or activation state of CD8 T cells.