CTLA-4 Checkpoint Research Articles

BTLA transcriptomic expression correlates with high levels of PD-1, PD-L2, and CTLA-4 checkpoints and with its ligand, HVEM, across diverse solid cancers.

e14641 Background: B and T lymphocyte attenuator (BTLA) is an immune checkpoint that is highly expressed on tumor-specific T cells and has been shown to be upregulated in several cancer types. The binding of BTLA to its ligand herpesvirus entry mediator (HVEM, also known as TNFRSF14) inhibits activation and proliferation of T lymphocytes, leading to decreased tumor killing. Early clinical trials of BTLA inhibitors are ongoing with preliminary results showing modest effects in advanced solid tumors. More recent clinical data suggests that combination checkpoint therapy with anti-BTLA and anti-PD-1 treatment provides greater benefit compared to monotherapy in patients with lymphoma. Methods: We analyzed RNA expression levels of 397 genes in various solid tumor types from 514 patients with various types of solid tumors seen at University of San Diego (UCSD), Moores Cancer Center. RNA expression was quantified at a CLIA-approved laboratory Omniseq (https://www.omniseq.com). Transcript abundance was normalized to internal housekeeping gene profiles and ranked (0-100 percentile) in a standardized manner to a reference population of 735 tumors spanning 35 histologies. We analyzed tumors with “High” (75-100 percentile rank) BTLA expression profiles. Odds ratio for high BTLA expression was calculated and multivariate analysis was utilized to determine significant correlations for multiple genes. Results: A total of 96 (18.7%) tumors had high BTLA (>75) expression across 32 different histologies. Cancers with the highest proportion of BTLA expression were small intestine (42%), breast (31%), pancreatic (29%), stomach (24%), neuroendocrine (20%), lung (20%), head and neck (17%) and colorectal (13%). There was significant association for BTLA and high PD-1 (p < 0.001), high CTLA-4 (p < 0.001), high PD-L2 (p = 0.05) and its ligand HVEM (p < 0.01). There was no significant association between BTLA expression and PD-L1, gender or stomach, neuroendocrine, head and neck, and lung histologies. Conclusions: High BTLA expression was found in a large number of tumor samples and significantly associated with other immune checkpoints with FDA-approved drugs. Furthermore, HVEM expression (ligand for BTLA) significantly correlates with high BTLA transcriptome levels. The BTLA/HVEM pathway has been associated with suppression of T cell-mediated anti-tumor activity and resistance to anti-PD-1 immunotherapy leading to poor clinical outcomes. The utilization of combination checkpoint therapy involving BTLA inhibitors and specific checkpoint blockade is currently being explored. Our results suggest that patient selection based on the RNA expression level of immune markers matched to corresponding immunotherapy agent, rather than a population-based approach, may be ideal for optimizing treatment response.

Single-cell RNA and T cell receptor (TCR) sequencing in patients with HPV-positive head and neck squamous cell carcinoma (HNSCC) after induction CTLA4 and PD-1 immune checkpoint blockade (ICB).

6056 Background: Combination CTLA-4 and PD-1 ICB results in durable responses in patients with recurrent and metastatic HNSCC and therefore justifies further investigation in the induction or neoadjuvant setting. Methods: We investigated features of the tumor immune microenvironment (TIME) associated with MHR after induction CTLA-4 and PD-1 ICB in patients with newly diagnosed HPV-positive HNSCC. Tumor samples were collected at baseline and on treatment from 31 patients enrolled in a phase 2 trial of a 6-week cycle of CTLA-4 and PD-1 ICB induction followed by dose/volume-adapted IMRT (50-66Gy) concurrent with cycle 2. Tumors were evaluated for histological response and single-cell RNA sequencing (scRNA-seq) and scTCR-seq were performed on the 10X genomics platform. After stringent clustering and annotation of scRNA-seq data, 76,319 CD8+ and 78,622 CD4+ T cells with paired TCR sequence data were evaluable for transcriptomic, TCR repertoire and clonotype differentiation analysis. Results: Percent reduction in tumor viability on histology correlated significantly with reduction in tumor cell proportion in scRNA-seq data (R2= 0.7). Thirteen (48%) of 27 patients with paired samples (missing data due to COVID) had MHR, defined as ≤10% residual tumor viability on ICB treatment. Through TCR tracing, over 100 T cell clonotypes that expanded significantly (p < 0.05, Fisher’s exact) post-ICB were identified. Highly expanded clonotypes resided mainly in exhausted CD8+ T cell clusters and exhibited a tissue resident memory (TRM) phenotype. Examination of their functional states revealed a variety of T cell modulatory trajectories, including reverse transition from exhausted to less exhausted states and from memory to functional states. When compared to patients without MHR, those with MHR had significantly higher ICB-induced TCR clonotype expansion (p = 0.025, Wilcoxon), reductions of activated Tregs (p = 0.003, Wilcoxon) and terminally exhausted CD8+ T cells (p = 0.003, Wilcoxon), and increase of polyfunctional CD8+ T cells (p = 0.014, Wilcoxon). A lasso regression model associated T cell expansion, basal 7-gene TRM and 5-gene effector scores, and on-treatment proliferation score and effector cell proportion with percent reduction in tumor viability (R2 = 0.66). Conclusions: In HPV-HNSCC, induction CTLA4 and PD1 ICB lead to extensive reinvigoration of CD8+ T cell clonotypes with both an exhausted and TRM phenotype, revealing a high degree of plasticity of distinct T cell clones. Paired RNA and TCR profiling facilitated identification of potentially tumor reactive and ICB-responsive T cells and clonotypes and identified several TIME features associated with tumor cell death. Clinical trial information: NCT03799445 .

KYNU-related transcriptome profile and clinical outcome from 2994 breast tumors

The Catabolism of tryptophan modulates the immunosuppressive microenvironment in tumors. KYNU (Kynureninase) served as an enzyme involved in amino acid tryptophan catabolism through the kynurenine pathway. The molecular and clinical characteristics of KYNU remain unclear, and the impact of KYNU on the immune response has not been reported until now. We analyzed large-scale transcriptome data and related clinical information on 2994 breast cancer patients to characterize KYNU's role in breast cancer. There was a strong correlation between KYNU expression and major molecular and clinical characteristics, and it was more likely to be overexpressed in patients with higher malignancy subtypes. Inflammatory and immune responses were strongly correlated with KYNU. KYNU was also associated with immune modulators at the pan-cancer level, particularly its potential synergistic role with other immune checkpoints in breast cancer. KYNU expression was linked to the malignancy grade of breast cancer and predicted poorer outcomes. Tryptophan catabolism might play an important role in modulating the tumor immune microenvironment through KYNU. More significantly, KYNU might synergize with CTLA4, PDL2, IDO1, and other immune checkpoints, contributing to the development of combination cancer immunotherapy targeting KYNU and other checkpoints. As far as we are aware, this is the biggest and most thorough study describing KYNU's role in breast cancer.

Molecular characterization of nectin-4 in non-small cell lung cancer subtypes.

e21119 Background: Nectin-4 (Nectin cell adhesion molecule-4) is a tumor associated antigen overexpressed in multiple solid tumor types. Studies show that over 60% of NSCLC are nectin-4 overexpressed. As enfortumab vedotin, an antibody-drug conjugate directed against nectin-4, has been FDA approved for advanced urothelial carcinoma, this holds treatment implications. Here, we investigated nectin-4 expression in NSCLC subtypes. Methods: 27,607 NSCLC tumors were tested for whole transcriptome sequencing (WTS, NovaSeq) and NextGen DNA sequencing (592 gene panel or whole exome sequencing, WES) at Caris Life Sciences (Phoenix, AZ). Tumors were analyzed overall in quartiles by nectin-4 expression (Q4-greatest, Q1-least) and further analyzed in the adenocarcinoma (AD) and squamous carcinoma (SQ) cohorts. PD-L1 expression was tested by IHC (Dako 22C3). Immune cell populations were estimated by QuanTISeq. Statistical significance was determined using Chi-square/Fisher-Exact/Mann-Whitney U tests and adjusted for multiple comparisons (q < 0.05). Results: We saw significantly greater expression of nectin-4 in SQ (median TPM- 15.68) versus AD tumors (median TPM - 9.88) (p < 0.05). We saw a greater prevalence of NFE2L2, STK11, ERBB2 mutations and genomic loss of heterozygosity (LOH) but a lower percentage of PD-L1+ tumors in Q4 vs Q1 tumors (all q-value < 0.05, Table 1). mRNA expression of immune checkpoints PDL1, CTLA4, CD80, CD86, HAVCR2, and IDO1 was increased in Q4 tumors (1.1-1.3-fold, all q < 0.05). Q4 tumors had reduced estimates of M1 macrophages, regulatory T cells (Tregs), and CD8+ T cells and increased estimates of neutrophils and NK cells. The association of nectin-4 expression with the immune landscapes of AD and SQ was similar. Q4 tumors in AD and SQ displayed increased expression of the above-mentioned immune checkpoints (q < 0.05). In AD and SQ, estimates of M1 macrophages, Tregs, and CD8+ T cells were reduced, but neutrophils and NK cells were increased in Q4 tumors (q < 0.05). The pattern of molecular alterations was different in AD and SQ. While KEAP1, STK11 and ERBB2 mutations were significantly enriched in AD Q4 tumors, NFE2L2 mutations were significantly enriched in SQ Q4 tumors (Table 1). Prevalence of LOH was higher and PD-L1+ tumors was lower in Q4 tumors in both AD and SQ (Table 1). Conclusions: NFE2L2 alterations in SQ and STK11, KEAP1 mutations in AD, which are associated with poor immunotherapy (IO) response, were enriched in Q4 tumors. This suggests that the immune landscape associated with high nectin-4 expression in NSCLC may be driven by the dysregulated KEAP1-NFE2L2 pathway. Targeted therapy towards nectin-4 may benefit these NSCLC subtypes that do not respond well to IO. [Table: see text]

F.2 Multiplatform molecular analysis of vestibular schwannoma reveals two robust subgroups with distinct microenvironment

Background: Vestibular schwannoma (VS) is the most common tumour of the cerebellopontine angle and poses a significant morbidity for patients. While many exhibit benign behaviour, others have a more aggressive nature. There is a need for a better understanding of the molecular landscape, and important subgroups therein, of this disease. Methods: We select all VS from our tumour bank with both methylation and RNA profiling. Unsupervised clustering methods were used to define two distinct molecular subgroups of VS which were explored using computational techniques including bulk deconvolution analysis, gene pathway enrichment analysis, and drug repurposing analysis. Methylation data from two other cohorts were used to validate our findings. Results: A total of 75 tumours were analyzed. Consensus clustering and similarity network fusion defined two subgroups (“immunogenic” and “proliferative”) with significant differences in immune, stroma, and tumour cell abundance. Gene network analysis and computational drug repurposing found critical differences in targets of immune checkpoint inhibition PD-1 and CTLA-4, the MEK pathway, and the epithelial-to-mesenchymal transition program with associated candidate drug targets, suggesting a need for subgroup-specific treatment/trial design in the future. Conclusions: We leverage computational tools with multi-omic molecular data to define two robust subgroups of vestibular schwannoma with differences in microenvironment and therapeutic vulnerabilities.

Immunogenomic Landscape of Neuroendocrine Prostate Cancer.

Patients with neuroendocrine prostate cancer (NEPC) are often managed with immunotherapy regimens extrapolated from small-cell lung cancer (SCLC). We sought to evaluate the tumor immune landscape of NEPC compared with other prostate cancer types and SCLC. In this retrospective study, a cohort of 170 patients with 230 RNA-sequencing and 104 matched whole-exome sequencing data were analyzed. Differences in immune and stromal constituents, frequency of genomic alterations, and associations with outcomes were evaluated. In our cohort, 36% of the prostate tumors were identified as CD8+ T-cell inflamed, whereas the remaining 64% were T-cell depleted. T-cell-inflamed tumors were enriched in anti-inflammatory M2 macrophages and exhausted T cells and associated with shorter overall survival relative to T-cell-depleted tumors (HR, 2.62; P < 0.05). Among all prostate cancer types in the cohort, NEPC was identified to be the most immune depleted, wherein only 9 out of the 36 total NEPC tumors were classified as T-cell inflamed. These inflamed NEPC cases were enriched in IFN gamma signaling and PD-1 signaling compared with other NEPC tumors. Comparison of NEPC with SCLC revealed that NEPC had poor immune content and less mutations compared with SCLC, but expression of checkpoint genes PD-L1 and CTLA-4 was comparable between NEPC and SCLC. NEPC is characterized by a relatively immune-depleted tumor immune microenvironment compared with other primary and metastatic prostate adenocarcinoma except in a minority of cases. These findings may inform development of immunotherapy strategies for patients with advanced prostate cancer.

Effects of SMC1A on immune microenvironment and cancer stem cells in colon adenocarcinoma.

Our previous study suggested that SMC1 has significant functions in colorectal cancer (CRC). However, few reports have shown the effects of structural maintenance of chromosomes 1 (SMC1A) on the immune microenvironment and tumor stem cells. The Cancer Genome Atlas (TCGA) database, CPTAC database, Human Protein Atlas (HPA) database, the Cancer Cell Line Encyclopedia (CCLE) and Tumor Immune Single-cell Hub were used. Flow cytometry and immunohistochemical analysis were checked for immune infiltration on MC38 mice model. Human CRC tissues were tested with RT-qPCR. The mRNA and protein levels of SMC1A were increased in colon adenocarcinoma (COAD) samples.SMC1A was associated with DNA activity. Interestingly, SMC1A was highly expressed in many types of immune cells at single-cell levels. Moreover, the high expression of SMC1A was positively correlated with immune infiltration, and immunohistochemical analysis showed that SMC1A was positively associated with CD45 expression in MC38 mice model. Also, the percentage of IL4+ CD4+ T cells (Th2) and FoxP3+ CD4+ T cells (Tregs) was significantly higher in the SMC1A overexpression group than in control by flow cytometry assay in vivo. SMC1A expression could affect the proliferation of T cells in the mice model. The mutation and somatic cell copy number variation (SCNV) of SMC1A were also associated with immune cell infiltration. In addition to SMC1A in the "hot" T-cell inflammatory microenvironment of colon cancer, SMC1A also positively correlates with the immune checkpoint genes CD274, CTLA4, and PDCD1 in colon adenocarcinoma (COAD) samples. Furthermore, we also found that SMC1A plays a positive correlation with the induction of cancer stem cells (CSCs). Our results also showed that miR-23b-3p binds SMC1A. SMC1A may be a bidirectional target switch that simultaneously regulates the immune microenvironment and tumor stem cells. Moreover, SMC1A may be a biomarker for the prediction of immune checkpoint inhibitor (ICI) therapy.

A new prediction model of hepatocellular carcinoma based on N7-methylguanosine modification

PurposeHepatocellular carcinoma (HCC) is a kind of primary liver cancer. It is a common malignant tumor of digestive system that is difficult to predict the prognosis of patients. As an important epigenetic modification, N7 methyl guanosine (m7G) is indispensable in gene regulation. This regulation may affect the development and occurrence of cancer. However, the prognosis of long non coding RNAs (lncRNAs) in HCC is limited, especially how m7G-related lncRNAs regulate the development of HCC has not been reported.MethodsThe Cancer Genome Atlas (TCGA) provides us with the expression data and corresponding clinical information of HCC patients we need. We used a series of statistical methods to screen four kinds of m7G-related lncRNAs related to HCC prognosis and through a series of verifications, the results were in line with our expectations. Finally, we also explored the IC50 difference and correlation analysis of various common chemotherapy drugs.ResultOur study identified four differentially expressed m7g-related lncRNAs associated with HCC prognosis. Survival curve analysis showed that high risk lncRNAs would lead to poor prognosis of HCC patients. M7G signature's AUC was 0.789, which shows that the prognosis model we studied has certain significance in predicting the prognosis of HCC patients. Moreover, our study found that different risk groups have different immune and tumor related pathways through gene set enrichment analysis. In addition, many immune cell functions are significantly different among different risk groups, such as T cell functions, including coordination of type I INF response and coordination of type II INF response. The expression of PDCD1, HHLA2, CTLA-4 and many other immune checkpoints in different risk groups is also different. Additionally, we analyzed the differences of IC50 and risk correlation of 15 chemotherapeutic drugs among different risk groups.ConclusionA novel lncRNAs associated with m7G predicts the prognosis of HCC.

Secondary IgA Nephropathy and IgA-Associated Nephropathy: A Systematic Review of Case Reports.

Primary (pIgAN), secondary IgA nephropathy (sIgAN), and IgA-associated nephropathy can be distinguished. While pIgAN has been thoroughly studied, information about the etiology of sIgAN remains scarce. As concerns sIgAN, several studies suggest that different etiologic factors play a role and ultimately lead to a pathophysiologic process similar to that of pIgAN. In this article, we review a vast number of cases in order to determine the novel putative underlying diseases of sIgAN. Moreover, updates on the common pathophysiology of primary disorders and sIgAN are presented. We identified liver, gastrointestinal, oncological, dermatological, autoimmune, and respiratory diseases, as well as infectious, iatrogenic, and environmental factors, as triggers of sIgAN. As novel biological therapies for listed underlying diseases emerge, we suggest implementing drug-induced sIgAN as a new significant category. Clinicians should acknowledge the possibility of sIgAN progression in patients treated with TNF-α inhibitors, IL-12/IL-23-inhibitors, immune checkpoint inhibitors, CTLA-4, oral anticoagulants, thioureylene derivatives, and anti-vascular endothelial growth factor drugs.

Abstract 6633: T regulatory cell subsets in colorectal cancer: friends or foes

Abstract T cells in the tumor microenvironment (TME) have diverse roles in anti-tumor immunity. Different T cell subsets may have opposing roles in tumor progression, especially in inflammatory cancers such as colorectal cancer (CRC). In different series of studies, we performed extensive characterization and critical analyses of T regulatory cell (Treg)-related markers and key inhibitory immune checkpoints (ICs) in CD4+ and CD8+ T cell subsets in the TME and periphery of CRC patients. We found a significant increase in levels of CD4+FoxP3+Helios+ T cells, which represent potentially highly immunosuppressive Tregs, in the TME. Additionally, tumor-infiltrating CD4+ T cells upregulated PD-1, CTLA-4, TIM-3 and LAG-3 immune checkpoints. CTLA-4, TIM-3, and LAG-3 were mainly co-expressed on FoxP3+Helios+ Tregs in the TME. Additionally, we found that FoxP3 expression and ICs including PD-1, CTLA-4, TIM-3, and LAG-3 were significantly upregulated in tumor-infiltrating CD8+ T cells. We then investigated associations between different tumor-infiltrating CD4+ and CD8+ T cell subpopulations and disease-free survival (DFS). Interestingly, a high frequency of circulating CD4+FoxP3+ Tregs was associated with poorer DFS, while higher frequency of these cells in the TME was associated with better DFS. Additionally, high frequencies of circulating CD4+FoxP3+Helios+ Tregs and tumor-infiltrating CD4+FoxP3-Helios- T cells were associated with poorer DFS. Moreover, a high frequency of CD4+FoxP3+Helios-PD-1+ Tregs in circulation was associated with worse DFS. In contrast, high frequencies of CD4+TIM-3+ T cells, FoxP3+Helios+TIM-3+ Tregs, and FoxP3-Helios+TIM-3+ CD4+ T cells in circulation were associated with longer DFS. Additionally, we found that high levels of certain circulating CD8+ T cell subsets (TIM-3+, FoxP3-Helios-TIM-3+ and FoxP3-Helios+TIM-3+ cells) were associated with longer DFS. In the TME, elevated levels of CD25+ and TIM-3+ CD8+ T cells, and FoxP3+Helios-TIM-3+ CD8+ Tregs were associated with better DFS. These data show that circulating and tumor-infiltrating immune checkpoint-expressing CD4+ and CD8+ Treg/T cell subsets play different roles in disease prognoses, and certain subsets could serve as independent predictive biomarkers in CRC patients. Citation Format: Eyad Elkord. T regulatory cell subsets in colorectal cancer: friends or foes [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 6633.

Abstract 6424: Immune characteristics and anti-PD-1-induced reinvigoration capacity of tumor-infiltrating lymphocytes in ovarian clear cell carcinoma relative to high-grade serous ovarian carcinoma

Abstract Recent clinical trials have demonstrated the potential efficacy of immune checkpoint inhibitors (ICIs) for ovarian clear cell carcinoma (OCCC). However, little is known about the immune characteristics of OCCC. In this study, we aimed to investigate the distinct immune characteristics of tumor-infiltrating lymphocytes (TILs) in OCCC to high-grade serous ovarian carcinoma (HGSOC). We isolated peripheral blood mononuclear cells (PBMCs) and TILs from patients with epithelial ovarian cancer. The expression of immune checkpoint receptors and T-cell transcription factors of TILs in OCCC (n=26) and HGSOC patients (n=44) were accessed using flow cytometry. TILs were ex vivo stimulated with anti-CD3 in the presence of anti-PD-1 and/or anti-CTLA-4, and their proliferation was assessed to predict response to ICIs. CD8 TILs and tumor-infiltrating regulatory T cells (Tregs) exhibited higher expression of immune checkpoint receptors, including PD-1, CTLA-4, and 4-1BB, compared to PBMCs. Tregs were more infiltrated in advanced/recurrent stage than early stage OCCC. However, immune characteristics of CD8 TILs and Tregs were not significantly different regardless of stage. When we compared the characteristics of TILs in OCCC (n=26) with those in HGSOC (n=44), the expression of PD-1 on CD8 TILs was significantly lower in OCCC than in HGSOC. The frequencies of PD-1highCD8 TILs and PD-1+TOX+CD8 TILs were also lower in OCCC than HGSOC. In ex vivo assay (n=19), 9 cases responded to anti-PD-1 in terms of enhanced proliferation capacity of CD8 TILs. In addition, when anti-CTLA-4 was added to anti-PD-1, an additional increase in proliferation of CD8 TILs was observed in patients who responded to anti-PD-1. Responders to anti-PD-1 had significantly lower frequencies of effector Tregs in the TILs than non-responders. Overall, CD8 TIL in OCCC was found to be less exhausted than HGSOC in terms of PD-1 and TOX expressions. Tumor-infiltrating Tregs affected on reinvigoration ability of CD8 TILs upon ICIs treatment in OCCC. This study provides the rationale and evidence for establishing the optimal strategies for ICIs treatment in patients with OCCC. Citation Format: Junsik Park, Yong Jae Lee, Jung Chul Kim, Jung-Yun Lee. Immune characteristics and anti-PD-1-induced reinvigoration capacity of tumor-infiltrating lymphocytes in ovarian clear cell carcinoma relative to high-grade serous ovarian carcinoma. [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 6424.

Abstract 4615: Differential immune characteristics and anti-PD-1-induced reinvigoration capacity of tumor-infiltrating lymphocytes according to ProMisE classifier in endometrial cancer

Abstract Endometrial cancer (EC), one of the most common gynecological malignancies, has been gradually increasing worldwide. The Cancer Genome Atlas endometrial collaborative project discovered 4 distinct prognostic genomic subtypes, and the Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE) was developed: POLE-mutated, mismatch repair deficiency (MMR-D), non-specific molecular profile (NSMP), and p53-abnormal (p53abn). In the era of immunotherapy, immune checkpoint inhibitors (ICIs) become a definite management of EC, both as single agent or in combination with other targeted agents. However, the characteristics of the tumor immune microenvironment according to molecular classification in EC are not well known. This study was conducted to identify distinct immune properties of tumor infiltrating lymphocytes (TILs) according to molecular classification in EC and find optimal therapeutic targets in each molecular subtypes. We isolated peripheral blood mononuclear cells (PBMCs) and TILs from 81 patients with EC. The expression of immune checkpoint receptors and T-cell transcription factors of TILs were examined using flow cytometry. Sixty-six patients were evaluated according to the ProMisE algorithm based on sequencing for the presence of POLE mutations, immunohistochemistry for MMR proteins and p53 (POLE-mut, n=6; MMR-D, n=17; p53abn, n=20; NSMP, n=23). Tumors were categorized into one of the four molecular subtypes. TILs were ex vivo stimulated with anti-CD3 in the presence of anti-PD-1, and their proliferation was assessed to predict ICI-induced reinvigoration capacity of CD8 TILs. Comparing T-cell transcription factors (TCF-1 and TOX), CD8 TILs showed higher expression of TOX, and lower expression of TCF-1. When comparing the immune characteristics of TILs according to molecular subtypes, Tregs of POLE-mut showed significantly lower expression of CTLA-4 and Ki-67 than that of MMR-D. In addition, CD8 TILs of MMR-D showed higher expression of immune checkpoint receptors, including PD-1, CTLA-4, and TIM-3, and lower expression of TCF-1 than those of p53abn. CD8+TILs of p53abn showed significantly higher expression of CD226 than those of MMR-D. In particular, the frequency of antigen reactive CD39+CD103+CD8 T cells significantly lower in p53abn than in MMR-D. CD8 TILs of NSMP showed higher expression of TOX than those of MMR-D. In ex vivo T cell proliferation assay (n=49), 80.0% POLE-mut (4 of 5), 46.2% MMR-D (6 of 13), 35.7% p53abn (5 of 14) and 35.36% NSMP (6 of 17) showed enhanced proliferation of CD8 TILs upon anti-PD-1 treatment. In endometrial cancer, TILs showed distinct immune properties according to ProMisE classification. Further study is needed to develop optimal treatment targets for the p53abn and NSMP subtype, which is non-immunogenic and hardly reinvigorated by ICIs. Citation Format: Jung Chul Kim, Junsik Park, Yong Jae Lee, Sunghoon Kim, Sang Wun Kim, Jung-Yun Lee. Differential immune characteristics and anti-PD-1-induced reinvigoration capacity of tumor-infiltrating lymphocytes according to ProMisE classifier in endometrial 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 4615.

Abstract 1199: Discovery of subtype-specific and therapy associated effects on the tumor immune microenvironment in pediatric neuroblastoma

Abstract Background: Neuroblastoma (NB) is the 3rd most common childhood cancer and accounts for 15% of all pediatric cancer deaths. Recently, immunotherapy using monoclonal antibodies targeting GD2 have improved survival rates for some patients with NB. Unfortunately, this response is not uniform, suggesting an incomplete understanding of the underlying immune biology. Large-scale sequencing of patient tumors have suggested that NB has diverse immune microenvironments (TMEs), which are associated with MYCN-amplification (A) and patient outcomes. These results need to be further validated, specifically to determine whether the infiltrating immune cells can interact with tumor cells and if the TME is impacted by therapeutic pressures. We hypothesized the TME is dynamic, changing with therapy, influenced by molecular subtype, and associated with patient outcomes. Methods: To better understand the NB TME, we obtained 93 clinically annotated tumors from 72 pediatric patients with NB, consisting of high-risk primary and metastatic tumors both pre- and post- chemotherapy. We designed multiplexed antibody panels targeting immune cells and performed either imaging mass cytometry (IMC) (n = 46) or NanoString GeoMx DSP (n = 47). Results: We identified 4 different immune cell types (CD8, CD4, myeloid, and NK cells) and confirmed that MYCN-non amplified (NA) tumors display higher frequencies of lymphocytes including CD4 (p &amp;lt; 0.003) and CD8 (p &amp;lt; 0.005) T-cells. Using nearest neighbors’ analysis, we found that CD4 cells are closer to tumor (p = 6.24E-16) and CD8 T-cells (p = 7.55E-11) in MYCN-NA tumors compared to MYCN-A. However, in MYCN-NA tumors, myeloid cells are also closer to tumor, (p = 1.71E-68), CD4 (p = 4.72E-58), and CD8 T-cells (p = 1.27E-70). Furthermore, we find that all immune cell subsets are further away from tumor cells independently of subtype following exposure to chemotherapy, and that there is a decrease (p = 0.0091) in the number of myeloid cells in MYCN-NA tumors, but not MYCN-A. Interestingly, we also observed an increased expression of the immune checkpoints CTLA-4 (p = 0.043) and the exhaustion marker TIM-3 (p = 2.05E-5), but not PD-1, PD-L1, or PD-L2, post chemotherapy, suggesting blockade of CTLA-4 or TIM-3 could improve response to therapy in these patients. Notably, high expression of CD56, a marker for both NK cells and NB, was associated with increased overall survival, indicating a potential role of NK cells in improving outcomes. Conclusions: Using two independent protein-based profiling methods, we investigated the TME in clinically annotated patient NBs. We discovered that the TME in NB varies with tumor subtype and changes with chemotherapy. We find that there is an upregulation of immune check point markers post chemotherapy. These results can inform future trials to optimize the timing and specificity of novel immunotherapeutic approaches for these high-risk patients. Citation Format: Katherine E. Masih, Zahin Islam, Paul Aiyetan, Ben J. Somerville, Igor B. Kuznetsov, William Bocik, Daniel R. Catchpoole, Jun S. Wei, Javed Khan. Discovery of subtype-specific and therapy associated effects on the tumor immune microenvironment in pediatric neuroblastoma [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 1199.

Impaired tolerance to the autoantigen LL-37 in acute coronary syndrome.

LL-37 is the only member of the cathelicidin family of antimicrobial peptides in humans and is an autoantigen in several autoimmune diseases and in acute coronary syndrome (ACS). In this report, we profiled the specific T cell response to the autoimmune self-antigen LL-37 and investigated the factors modulating the response in peripheral blood mononuclear cells (PBMCs) of healthy subjects and ACS patients. The activation induced marker (AIM) assay demonstrated differential T cell profiles characterized by the persistence of CD134 and CD137, markers that impair tolerance and promote immune effector and memory response, in ACS compared to Controls. Specifically, CD8+CD69+CD137+ T cells were significantly increased by LL-37 stimulation in ACS PBMCs. T effector cell response to LL-37 were either HLA dependent or independent as determined by blocking with monoclonal antibody to either Class-I HLA or Class-II HLA. Blocking of immune checkpoints PD-1 and CTLA-4 demonstrated the control of self-reactive T cell response to LL-37 was modulated predominantly by CTLA-4. Platelets from healthy controls down-modulated CD8+CD69+CD137+ T cell response to LL-37 in autologous PBMCs. CD8+CD69+CD137+ T cell AIM profile negatively correlated with platelet count in ACS patients. Our report demonstrates that the immune response to the autoantigen LL-37 in ACS patients is characterized specifically by CD8+CD69+CD137+ T cell AIM profile with persistent T cell activation and the generation of immunologic memory. The results provide potentially novel insight into mechanistic pathways of antigen-specific immune signaling in ACS.

Inappropriate Expression of PD-1 and CTLA-4 Checkpoints in Myeloma Patients Is More Pronounced at Diagnosis: Implications for Time to Progression and Response to Therapeutic Checkpoint Inhibitors.

Multiple myeloma (MM) is a hematologic malignancy characterized by severely profound immune dysfunction. Therefore, the efficacy of drugs targeting the immune environments, such as immune checkpoint inhibitors (ICIs), is of high clinical importance. However, several clinical trials evaluating ICIs in MM in different therapeutic combinations revealed underwhelming results showing a lack of clinical efficacy and excessive side effects. The underlying mechanisms of resistance to ICIs observed in the majority of MM patients are still under investigation. Recently, we demonstrated that inappropriate expression of PD-1 and CTLA-4 on CD4 T cells in active MM is associated with adverse clinical outcomes and treatment status. The aim of the current study was to determine the usefulness of immune checkpoint expression assessment as a predictive biomarker of the response to therapeutic inhibitors. For this purpose, along with checkpoint expression estimated by flow cytometry, we evaluated the time to progression (TTP) of MM patients at different clinical stages (disease diagnosis and relapse) depending on the checkpoint expression level; the cut-off point (dividing patients into low and high expressors) was selected based on the median value. Herein, we confirmed the defective levels of regulatory PD-1, CTLA-4 receptors, and the CD69 marker activation in newly diagnosed (ND) patients, whereas relapsed/refractory patients (RR) exhibited their recovered values and reactivity. Additionally, substantially higher populations of senescent CD4+CD28- T cells were found in MM, primarily in NDMM subjects. These observations suggest the existence of two dysfunctional states in MM CD4 T cells with the predominance of immunosenescence at disease diagnosis and exhaustion at relapse, thus implying different responsiveness to the external receptor blockade depending on the disease stage. Furthermore, we found that lower CTLA-4 levels in NDMM patients or higher PD-1 expression in RRMM patients may predict early relapse. In conclusion, our study clearly showed that the checkpoint level in CD4 T cells may significantly affect the time to MM progression concerning the treatment status. Therefore, when considering novel therapies and potent combinations, it should be taken into account that blocking PD-1 rather than CTLA-4 might be a beneficial form of immunotherapy for only a proportion of RRMM patients.

CARD11 gain-of-function mutation drives cell-autonomous accumulation of PD-1+ ICOShigh activated T cells, T-follicular, T-regulatory and T-follicular regulatory cells.

Germline CARD11 gain-of-function (GOF) mutations cause B cell Expansion with NF-κB and T cell Anergy (BENTA) disease, whilst somatic GOF CARD11 mutations recur in diffuse large B cell lymphoma (DLBCL) and in up to 30% of the peripheral T cell lymphomas (PTCL) adult T cell leukemia/lymphoma (ATL), cutaneous T cell lymphoma (CTCL) and Sezary Syndrome. Despite their frequent acquisition by PTCL, the T cell-intrinsic effects of CARD11 GOF mutations are poorly understood. Here, we studied B and T lymphocytes in mice with a germline Nethyl-N-nitrosourea (ENU)-induced Card11M365K mutation identical to a mutation identified in DLBCL and modifying a conserved region of the CARD11 coiled-coil domain recurrently mutated in DLBCL and PTCL. Our results demonstrate that CARD11.M365K is a GOF protein that increases B and T lymphocyte activation and proliferation following antigen receptor stimulation. Germline Card11M365K mutation was insufficient alone to cause B or T-lymphoma, but increased accumulation of germinal center (GC) B cells in unimmunized and immunized mice. Card11M365K mutation caused cell-intrinsic over-accumulation of activated T cells, T regulatory (TREG), T follicular (TFH) and T follicular regulatory (TFR) cells expressing increased levels of ICOS, CTLA-4 and PD-1 checkpoint molecules. Our results reveal CARD11 as an important, cell-autonomous positive regulator of TFH, TREG and TFR cells. They highlight T cell-intrinsic effects of a GOF mutation in the CARD11 gene, which is recurrently mutated in T cell malignancies that are often aggressive and associated with variable clinical outcomes.

Abstract P2-20-07: Immunotherapy becomes a treatment option in cryoablated Luminal A breast cancers

Abstract Background: Most breast cancers are not inherently immunogenic, and as a result are difficult to treat with immunotherapy. However, recent research has shown that triple-negative breast cancer (TNBC) and HER-2 positive (HER2) breast cancers can stimulate some level of an immune response. In contrast, the most common form of breast cancer, the luminal A (hormone receptor-positive (HR+)/HER-2 negative), has shown low involvement of tumor-infiltrating lymphocytes (TILs) and low expression of immune checkpoint inhibitors specifically programmed death-ligand-1 (PD-L1). Cryoablation, the destruction of cells using ultra-low temperatures, has been used as a primary treatment method for benign breast tumors and is in clinical trials to evaluate its use for invasive breast cancer. A secondary effect of cryoablation is the release of cellular proteins that can function as neoantigens and are in their native folded state We hypothesize that release of these native neoantigens might trigger an immune response capable of preventing/reducing metastasis and local relapse. In this pilot study, we evaluated biopsy material, cryoablated specimens and sentinel lymph nodes (SLN) from patients enrolled in the ACOSOG Z1072 trial at Lankenau Medical Center (LMC) [N=18] with cancers &amp;lt; 2 cm. Responses were compared to patients treated with surgical resection. Methods: After obtaining IRB approval for retrospective analyses of specimens from the ACOSOG Z1072 trial, these samples were evaluated with immunohistochemistry (IHC) using commercially available antibodies and standard techniques to determine changes in CD4, CD8, CD20, CD21, CD1c levels, as well as the immune checkpoint regulators PD-1, PD-L1 and CTLA-4, and the immune modulator IDO1. Patient samples included biopsy, surgical material, and SLN collected from the patients and were compared with patients of similar age, tumor characteristics and time to surgery. Per the ACOSOG trial protocol, tumors had to be surgically removed within 28 days of cryoablation, but the exact time was left to the surgeon’s discretion. Participating surgeons at LMC preferred to remove tumors on average 24.7 days after ablation resulting in an average time from diagnosis to surgical removal of 43.3 days. Results: Cryoablation of the tumors resulted in coagulative necrosis presenting as a gelatinous mass surrounded by a fibrous capsule. The ACOSOG trial demonstrated effective cryoablation-induced destruction of ER+ invasive ductal carcinoma lesions in 92% of patients (N=86). On IHC staining of the cryoablated samples, more CD8+ lymphocytes were identified compared to CD4+, which was consistent with pattern among non-cryoablated tumors, albeit to a lesser degree. Though no difference in percentage of PD-1 positive cells were observed between treatment modalities, positive cells in cryoablated tumors had mostly moderate-to-strong staining. We observed a 20% increase in cells positive for PD-L1 after cryoablation with predominantly strong staining. Though IDO1 had fewer positive cells in the tumor mass, the expression in SLN was higher with nearly all cells exhibiting strong staining. Compared to the patients who were treated with surgery alone, the SLNs of cryo patients had higher levels of CD20+ B cells as well as CD21+ follicular dendritic cells. CTLA-4 was seen sporadically, but with a slight preference for the surgery patients. Conclusion: We show that cryoablation of breast cancer lesions in vivo can induce an immune response in HR+ tumors, turning an immunogenically cold tumor into an immunogenically hot, tumor potentially responsive to check-point inhibitors and immune modulators. Possibly providing less toxic treatment options for elderly patients and/or patients with comorbidities All local cryo patients in the clinical trial are currently disease-free (F/U 5 - 13years), while 1 surgical patient is alive with late recurrence (11 years post-surgery). Citation Format: Zachary Aukers, Jonah Klein, Vincent Ciocca, Vlasta Zemba-Palko, Jennifer Sabol, Robin Ciocca, Laura Mandik-Nayak, Ned Carp, Margaretha Wallon. Immunotherapy becomes a treatment option in cryoablated Luminal A breast cancers [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-20-07.

Abstract PD2-10: MiR-150 expression in breast cancer cells attract infiltration of lymphocytes to tumor microenvironment and is associated with better survival of the patients

Abstract MicroRNA (miRNA) are known as a key player in tumor biology and is shown to epigenetically regulate a large number of protein-coding genes, including tumor-related genes. MiR-150, a hematopoietic cell-specific miRNA, has been suggested to have various effects on cell proliferation, differentiation, apoptosis, migration, and invasion. However, there has been no study that investigated the role of miR-150 in the tumor microenvironment (TME) of breast cancer patients. We hypothesized that miR-150 expressed in breast cancer cells attract infiltration of lymphocytes to tumor microenvironment and is associated with better survival of the patients. In silico analyses of 1961 breast cancer patients were performed using multiple independent large cohorts, and in vitro studies by overexpressing miR-150 using its mimic in triple negative breast cancer (TNBC) cell lines were conducted. We found that miR-150 expression in patient breast tumors were strongly correlated with immune-related gene set scores, Allograft rejection, IL6/JAK/STAT3 signaling, Interferon-γ response, Inflammatory response, IL2/STAT5 signaling, and complement, in Hallmark collection of gene set variation analyses consistently in both METABRIC and TCGA cohorts (all spearman’s rank correlation coefficient (r) &amp;gt; 0.50, all p &amp;lt; 0.01). MiR-150 expression was also strongly correlated with cytolytic activity (CYT) score in both cohorts (r = 0.824 and 0.786, respectively, both p &amp;lt; 0.01). Furthermore, miR-150 expression was significantly correlated with infiltrating fraction of CD8+ T cells (r = 0.799 and 0.525, respectively), CD4+ memory T cells (r = 0.759 and 0.656, respectively), dendritic cells (r = 0.735 and 0.696, respectively), and B cells (r = 0.759 and 0.576, respectively), as well as mRNA expression of major immune checkpoint molecules, including PD-1, CTLA4, IDO1, TIGIT, BTLA, and LAG3, in both cohorts (all r &amp;gt; 0.50, and all p &amp;lt; 0.01). MiR-150 expression in triple negative breast cancer (TNBC) was the highest among the subtypes (both p &amp;lt; 0.001). MiR-150 expression level was significantly correlated with Nottingham histologic grade (both p &amp;lt; 0.001). MiR-150 high tumor enriched not only immune-related gene sets but also apoptosis, KRAS signaling up, MTORC1, and p53 pathway by gene set enrichment analysis in both cohorts. High miR-150 expression patients were significantly associated with better overall survival (OS) in both cohorts (p &amp;lt; 0.001 and p = 0.030, respectively). Subgroup analysis revealed that a high miR-150 was associated with better OS in ER-positive/HER2-negative breast cancer in both cohorts (p = 0.002 and 0.044, respectively), and in TNBC in the METABRIC cohort (p = 0.006). Unexpectedly, overexpression of miR-150 by its mimic shown no significant effect on cell proliferation, migration, nor invasion consistently in two TNBC cell lines. On the other hand, overexpression of miR-150 by its mimic significantly attracted Jurkart immortalized lymphocytes consistently in two cell lines, which effect was abolished by addition of miR-150 inhibitor. Finally, we found that mimic overexpression of miR-150 significantly expressed multiple cytokines and multiple inflammatory signaling pathways which at least partially explained the increased attraction of T cells in patient samples and in vitro condition. In conclusion, miR-150 expression in breast cancer cells may be associated with better patient survival outcomes by attracting and activating immune cells in breast cancer TME. Citation Format: Masanori Oshi, Aparna Maiti, Raj.G Vaghjiani, Rongrong Wu, Li Yan, Akimitsu Yamada, Nitai Hait, Takashi Ishikawa, Itaru Endo, Kazuaki Takabe, Yoshihisa Tokumaru. MiR-150 expression in breast cancer cells attract infiltration of lymphocytes to tumor microenvironment and is associated with better survival of the patients [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD2-10.

Kynureninase Upregulation Is a Prominent Feature of NFR2-Activated Cancers and Is Associated with Tumor Immunosuppression and Poor Prognosis.

The nuclear factor erythroid 2-related factor 2 (NRF2) pathway is frequently activated in various cancer types. Aberrant activation of NRF2 in cancer is attributed to gain-of-function mutations in the NRF2-encoding gene NFE2L2 or a loss of function of its suppressor, Kelch-like ECH-associated protein 1 (KEAP1). NRF2 activation exerts pro-tumoral effects in part by altering cancer cell metabolism. Previously, we reported a novel mechanism of NRF2 tumoral immune suppression through the selective upregulation of the tryptophan-metabolizing enzyme kynureninase (KYNU) in lung adenocarcinoma. In the current study, we explored the relevance of NRF2-mediated KYNU upregulation across multiple cancer types. Specifically, using a gene expression dataset for 9801 tumors representing 32 cancer types from The Cancer Genome Atlas (TCGA), we demonstrated that elevated KYNU parallels increased gene-based signatures of NRF2-activation and that elevated tumoral KYNU mRNA expression is strongly associated with an immunosuppressive tumor microenvironment, marked by high expression of gene-based signatures of Tregs as well as the immune checkpoint blockade-related genes CD274 (PDL-1), PDCD1 (PD-1), and CTLA4, regardless of the cancer type. Cox proportional hazard models further revealed that increased tumoral KYNU gene expression was prognostic for poor overall survival in several cancer types, including thymoma, acute myeloid leukemia, low-grade glioma, kidney renal papillary cell carcinoma, stomach adenocarcinoma, and pancreatic ductal adenocarcinoma (PDAC). Using PDAC as a model system, we confirmed that siRNA-mediated knockdown of NRF2 reduced KYNU mRNA expression, whereas activation of NFE2L2 (the coding gene for NRF2) through either small-molecule agonists or siRNA-mediated knockdown of KEAP1 upregulated KYNU in PDAC cells. Metabolomic analyses of the conditioned medium from PDAC cell lines revealed elevated levels of KYNU-derived anthranilate, confirming that KYNU was enzymatically functional. Collectively, our study highlights the activation of the NRF2-KYNU axis as a multi-cancer phenomenon and supports the relevance of tumoral KYNU as a marker of tumor immunosuppression and as a prognostic marker for poor overall survival.

CTLA-4 inhibition facilitates follicular T and B cell interaction and the production of tumor-specific antibodies.

Immune checkpoint inhibitors (ICIs) induce activation and expansion of cytotoxic T cells. To depict a comprehensive immune cell landscape reshaped by the CTLA-4 checkpoint inhibitor, we performed single-cell RNA sequencing in a mouse syngeneic tumor transplant model. After CTLA-4 inhibition, tumor regression was accompanied by massive immune cell expansion, especially in T and B cells. We found that B cells in tumor transplant represented follicular, germinal center and plasma B cells, some of which shared identical B cell receptor clonotypes and possessed tumor reactivity. Furthermore, the posttreatment tumor contained a tertiary lymphoid-like structure with intermingled T and B cells. These data suggest germinal center formation within the tumor mass and in situ differentiation of tumor-specific plasma cells. Taken together, our data provide a panoramic view of the immune microenvironment after CTLA-4 inhibition and suggest a role for tumor-specific B cells in antitumor immunity.