Immune Checkpoint Blockade Immunotherapy Research Articles

NOTCH3 is a Prognostic Factor and Is Correlated With Immune Tolerance in Gastric Cancer.

IntroductionAlthough traditional treatments confer survival benefits to patients with gastric cancer (GC), many patients experience relapse soon after postoperative adjuvant therapy. Immune-related mechanisms play an important role in GC, and immunotherapeutic strategies are considered to be a promising direction for the treatment of GC. Thus, our study aimed to investigate the expression and prognostic significance of immune-related genes in GC.MethodsFormalin-fixed, paraffin-embedded samples were collected from 48 resectable GC patients. The transcriptome data of the tumor immune microenvironment were assessed using an immuno-oncology 395-gene panel RNA sequencing platform. The prognostic value of the 395 genes was analyzed and validated in the KM plotter and GEPIA databases. The data from The Cancer Genome Atlas (TCGA, downloaded from UCSC Xena repository) and Tumor IMmune Estimation Resource (TIMER) were used to evaluate the correlations between prognostic factors and immune signatures.ResultsAmong the 395 genes, NOTCH3 was identified as a good prognostic factor for GC patients. Its prognostic value was also suggested in both our GC cohort from Zhongshan Hospital and the public databases (KM plotter and GEPIA database). Mechanistically, high NOTCH3 expression correlated with a lower infiltration of activated CD8+ T cells and a higher infiltration of immunosuppressive cells including Tregs and M2 macrophages in the tumor microenvironment. Moreover, high NOTCH3 expression was accompanied by the increased expression of a series of immune checkpoint inhibitors, resulting in a dampened immune response. Interestingly, NOTCH3 expression had a negative association with well-documented predictive biomarkers of immune checkpoint blockade (ICB) immunotherapy, including tumor mutation burden (TMB), gene expression profiling (GEP) score and innate anti-PD-1 resistance (IPRES) signature.ConclusionThese findings uncovered a new mechanism by which NOTCH3 participates in the immune tolerance of GC, implying the potential of NOTCH3 as a therapeutic target or predictive marker for GC patients.

A mathematical model for the quantification of a patient's sensitivity to checkpoint inhibitors and long-term tumour burden.

A large proportion of patients with cancer are unresponsive to treatment with immune checkpoint blockade and other immunotherapies. Here, we report a mathematical model of the time-course of tumour responses to immune-checkpoint inhibitors. The model takes into account intrinsic tumour-growth rates, the rates of immune activation and of tumour–immune-cell interactions, and the efficacy of immune-mediated tumour killing. For 124 patients, four cancer types and two immunotherapy agents, the model reliably described the immune responses and final tumour burden across all different cancers and drug combinations examined. In validation cohorts from four clinical trials of checkpoint inhibitors (with a total of 177 patients), the model accurately stratified the patients according to reduced or increased long-term tumour burden. We also provide model-derived quantitative measures of treatment sensitivity for specific drug–cancer combinations. The model can be used to predict responses to therapy and to quantify specific drug–cancer sensitivities in individual patients.

A genomic signature for accurate classification and prediction of clinical outcomes in cancer patients treated with immune checkpoint blockade immunotherapy

Tumor mutational burden (TMB) is associated with clinical response to immunotherapy, but application has been limited to a subset of cancer patients. We hypothesized that advanced machine-learning and proper modeling could identify mutations that classify patients most likely to derive clinical benefits. Training data: Two sets of public whole-exome sequencing (WES) data for metastatic melanoma. Validation data: One set of public non-small cell lung cancer (NSCLC) data. Least Absolute Shrinkage and Selection Operator (LASSO) machine-learning and proper modeling were used to identify a set of mutations (biomarker) with maximum predictive accuracy (measured by AUROC). Kaplan–Meier and log-rank methods were used to test prediction of overall survival. The initial model considered 2139 mutations. After pruning, 161 mutations (11%) were retained. An optimal threshold of 0.41 divided patients into high-weight (HW) or low-weight (LW) TMB groups. Classification for HW-TMB was 100% (AUROC = 1.0) on melanoma learning/testing data; HW-TMB was a prognostic marker for longer overall survival. In validation data, HW-TMB was associated with survival (p = 0.0057) and predicted 6-month clinical benefit (AUROC = 0.83) in NSCLC. In conclusion, we developed and validated a 161-mutation genomic signature with “outstanding” 100% accuracy to classify melanoma patients by likelihood of response to immunotherapy. This biomarker can be adapted for clinical practice to improve cancer treatment and care.

An immune risk score with potential implications in prognosis and immunotherapy of metastatic melanoma

Melanoma is a highly aggressive cancer with a poor prognosis. We found that immune response played important roles in melanoma metastasis by GSEA analysis. Therefore, we constructed the immune risk score (IRS) by the LASSO-COX analysis in the sequencing metastatic samples from the TCGA database. Then, initial diagnosis patients with metastasis were selected as the test cohort. Importantly, we adopted overall survival (OS) as the survival outcome for initial diagnosis patients, while adopting the observed survival interval (OBS) as the survival outcome for sequencing samples which could avoid biologically meaningless associations. We found that the IRS had high power for predicting 2, 3 and 5-year survival in training (AUC = 0.70, 0.69 and 0.68) and test cohorts (AUC = 0.72, 0.70 and 0.65). The IRS was significantly associated with prognosis both in the metastatic samples (HR = 1.60, 95% CI = 1.16–2.19) and patients with metastasis (HR = 2.89, 95% CI = 1.69–4.53). we further used other independent melanoma cohorts from the GEO databases to confirm the reliability and validity of the IRS (P < 0.01 in all cohorts). The practical nomogram was also built using the IRS and clinical information with high c-index both in training (0.76, 95%CI = 0.72–0.80) and test cohorts (0.72, 95%CI = 0.65–0.79). Finally, IRS showed the predictive value of survival outcome and response of immunotherapy patients, and increased the predictive ability of current immune checkpoint gene markers. In conclusion, the IRS can serve as a potential biomarker for prognosis and responsiveness to immune checkpoint blockade immunotherapy in metastatic melanoma patients.

Abstract 1563: Prediction of immune-checkpoint blockade response in gastrointestinal cancer patients using a machine learning-based RNA signature

Abstract Background: Currently, the objective response rate of immune checkpoint blockade (ICB) immunotherapy in gastrointestinal (GI) cancers was still unsatisfying, underscoring the urgent need for the development of novel biomarkers. To date, candidate biomarkers in GI cancers include microsatellite instability (MSI), tumor mutational burden (TMB), program death ligand 1 (PD-L1) expression, and RNA signatures associated with T cell-inflamed tumor microenvironment. Here, aiming to precisely capture the pre-existing “responsive feature” in GI cancers, we adopted a machine learning strategy based on RNA expression profiling data. Methods: This retrospective study included 96 metastatic GI patients treated with ICBs, who were randomly assigned into the discovery (75%) and validation (25%) cohorts. All formalin-fixed paraffin-embedded (FFPE) tumor specimens were subjected to the 395-plex immune oncology (IO)-related gene target sequencing. Based on the RNA profiling data of patients with durable clinic benefit (DCB) or no durable benefit (NDB), a linear support vector machine (linearSVM) strategy was applied for predictive model construction. Results: Notably, the linearSVM strategy helps construct a 24-gene RNA signature (IO-score) for discriminating DCB and NDB, which comprises genes involving in tumor antigen, tumor suppressor/oncogene, lymphocyte markers, interferon and checkpoint signaling pathways. In specific, patients with higher IO-score demonstrated stronger DCB rates than lower IO-score (discovery cohort: 92.0% [23 of 25] vs. 4.3% [2 of 47], P &amp;lt; 0.001; validation cohort: 85.7% [6 of 7] vs. 17.6% [3 of 17], Fisher's exact test, P =0.004). Moreover, compared with IO-score low subgroup, IO-score high subgroup displayed improved overall survival (discovery cohort: hazard ratio (HR), 0.29; 95% CI, 0.15-0.56; P =0.003; validation cohort: HR, 0.32, 95% CI, 0.10-1.05, P =0.04) as well as progression free survival (discovery cohort: HR, 0.22; 95% CI, 0.13-0.38; P &amp;lt;0.001; validation cohort: HR, 0.23, 95% CI, 0.09-0.60, P =0.007). Importantly, IO-score reveals a higher predictive value in both cohorts (discovery: area under the receiver operating characteristic curve (AUC)=0.97, 95% CI, 0.93-1.0; validation: AUC=0.74, 95% CI, 0.51-0.97), when compared with TMB-High (AUC=0.69, 95% CI, 0.57-0.80), MSI-High (AUC=0.59, 95% CI, 0.45-0.73) and PD-L1 positivity (AUC=0.52, 95% CI, 0.37-0.67). Conclusion: The machine learning methodologies offer a promising approach for capturing the pre-existing “responsive feature” in both tumor and infiltrating immune cells. The novel RNA signature, IO-score, may help facilitate individualized management in immunotherapy in GI cancer patients. A larger cohort study would be useful to optimize the cutoff value of IO-score. Citation Format: Lin Shen, Henghui Zhang, Zhihao Lu, Huan Chen, Xi Jiao, Wei Zhou, Shuang Li, Ying Yang, Dandan Liang. Prediction of immune-checkpoint blockade response in gastrointestinal cancer patients using a machine learning-based RNA signature [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1563.

Abstract 1622: Microsatellite instability causes colorectal cancer cell death to trigger anti-tumor immune response

Abstract Colorectal cancer (CRC) is the second leading cause of cancer deaths in the western world. Approximately 15% of CRCs have defects in DNA mismatch repair (MMR) genes, which lead to frequent mutations in repetitive genomic sequences known as microsatellites. This kind of genomic instability, referred to as microsatellite instability (MSI), contributes to the emergence of highly immunogenic neoantigen peptides that can stimulate an antitumor response. As such, a subset of CRC patients with deficient MMR has a positive response to immune checkpoint blockade immunotherapy. However, the molecular basis of MSI-induced antitumor immune response is not well understood. To address this issue, we used CRISPR to genetically inactivate MutL homolog 1 (MLH1), a key MMR protein, in two microsatellite stable (MSS) murine colorectal cancer cell lines, CT26 and MC-38, which enabled us to directly compare isogenic MSI and MSS tumors in mice with an immuno-deficient or -competent microenvironment. The growth of MLH1-KO cells was comparable to the parental cells in immunocompromised mice. Upon transplantation into syngeneic, immunocompetent mice, the parental CT26 and MC-38 tumors rapidly proliferate. In contrast, the MLH1-KO tumors grew poorly under the same conditions, which was accompanied by apoptotic cell death, upregulation of inflammatory cytokines, and tumor infiltration of CD8+ T lymphocytes. Blocking apoptosis by caspase inhibition suppressed cytokine induction and T lymphocyte infiltration, suggesting a key role of apoptosis in triggering an antitumor immune response. Our current efforts are towards elucidating the mechanism of cell death and defining the associated immune signatures. Ultimately, a better understanding of the immunological consequences of MSI status in CRCs may help to develop more effective CRC therapies. Citation Format: Darleny Y. Lizardo, Yi-Jun Wang, Liheng Yang, Jian Yu, Lin Zhang. Microsatellite instability causes colorectal cancer cell death to trigger anti-tumor immune response [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1622.

Recent advance of nanosized drug delivery systems targeting immune checkpoints for combination cancer immunotherapy

Immune checkpoint blockade (ICB) therapy has gained increasing attention due to its remarkable therapeutic performance. However, its therapeutic performance was highly impaired by the low immunogenicity of the tumors, insufficient intratumoral infiltration of the T lymphocytes, and the immunosuppressive tumor microenvironment. To address the challenge of current ICB therapy, nanosized drug delivery systems have been extensively exploited to deliver various immune modulators (e.g., chemotherapeutics, photosensitizers, and immune checkpoint inhibitors) for improved ICB therapy. In this review, we provide a brief overview of the recent advance of nanosized drug delivery systems for combination ICB immunotherapy. We also discuss the challenges and provide perspectives for the clinical translation of nanosized drug delivery systems for cancer immunotherapy.

A pan-cancer analysis of ARID1A as a potential biomarker for immune checkpoint therapy.

3540 Background: AT-rich interactive domain 1A (ARID1A), encoding a subunit of the BAF (SWI/SNF) chromatin remodeling complex, is correlated with the origination and progress of tumor. Previous research on ARID1A gene revealed that ARID1A deficiency was associated with mismatch repair (MMR) and higher tumor mutation burden (TMB) level in cancer, which might cooperate with immune checkpoint blockade therapy. Methods: Next generation sequencing (NGS) data of 10336 pan-cancer patients were obtained from the MSK-IMPACT Clinical Sequencing cohort (MSKCC). NGS data of 15849 pan-cancer patients from Chinese clinical dataset were analyzed to explore the association between ARID1A gene mutation and TMB. TMB was defined as total number of somatic non-synonymous mutations in coding region. 853 advanced NSCLC patients from two independent cohorts (OAK study cohort and POPLAR study cohort) were used to analyze the correlation between ARID1A alteration and the efficacy of immune checkpoint blockade immunotherapies (ICIs). Results: In total, 8.62% (891/10336) of pan-cancer patients in MSKCC harbored ARID1A mutation and 8.47% (3188/37628) in Chinese cohort. In MSKCC cohort, the highest ARID1A mutation frequency tumor type was endometrial cancer (31.64%, 69/218), bladder cancer (26.95%, 114/423) and hepatobiliary cancer (17.18%, 61/355) come in second and third, respectively. While in Chinese cohort, the top three ARID1A mutation frequency tumor types were endometrial cancer (39.29%, 88/224), gastric carcinoma (17.80%, 318/1787) and urothelial carcinoma (17.18%, 83/483), respectively. ARID1A gene mutation was also associated with higher TMB in the Chinese pan-cancer cohort (P &lt; 0.0001). The highest medium TMB level of ARID1A mutation tumor type was Urothelial carcinoma with 18.63 Muts/Mb (n = 65). In addition, the TMB level and prognositic analysis were performed on patients in two independent NSCLC cohorts with ICIs, TMB level of ARID1A mutant group was higher than wild-type group with significant difference (P &lt; 0.0001). The overall survival (OS) of ARID1A mutation group were significantly shorter than wild-type group (OS, median, 6.80 vs 10.28 months; HR, 1.47; P = 0.0474), and a decreasing trend on progression-free survival (PFS) without significant difference (median, 1.46 vs 2.99 months; HR, 1.27; P = 0.1584). Conclusions: The results indicated that ARID1A gene mutation was associated with a higher TMB level in Chinese pan-cancer patients, and patients harboring these genes mutations might easily benefit from ICIs.

Hepatocellular carcinoma with ARID1A mutation is associated with higher TMB and poor survival.

e16667 Background: Hepatocellular carcinoma (HCC) is a heterogeneous disease that lacks molecular predictors of response to available treatments. AT-rich interactive domain 1A (ARID1A), a SWI/SNF chromatin remodeling gene, is commonly mutated in human cancers and hypothesized to be a tumor suppressor gene. In recent years, immune checkpoint blockade immunotherapies (ICIs) are promising therapies for multiple cancers including HCC, and tumor mutation burden (TMB) was an important biomarker to predict the efficacy of ICIs. Besides, previous research reported that ARID1A deficiency was associated with mismatch repair (MMR) in cancer, and may cooperated with ICIs. Methods: Whole exome sequencing data of 10336 pan-cancer patients including 353 HCC patients was obtained from the Cancer Genome Altas (TCGA). Next generation sequencing (NGS) data of 15849 pan-cancer patients including 1926 HCC patients from Chinese clinical dataset were analyzed to explore the correlation between ARID1A gene mutation and TMB. TMB was defined as total number of somatic non-synonymous mutations in coding region. Prognostic data of 136 HCC patients were obtained from the MSK-IMPACT Clinical Sequencing Cohort (MSKCC). Results: In total, 8.62% (891/10336) of pan-cancer patients in TCGA harboring ARID1A mutation and 8.47% (3188/37628) in Chinese cohort, while mutant percentage of HCC was 9.35% (33/353) in TCGA, 9.03% (174/1926) in Chinese cohort, the alternation frequency of ARID1A in two cohorts was no significant difference (P = 0.3334). The medium TMB level of ARID1A mutant group was higher than wild-type group with significant difference both in Chinese pan-cancer and HCC (medium TMB level, P &lt; 0.0001). Results of 18 kinds of ARID1A mutated tumors patients in TCGA cohort indicated that ARID1A mutation was an independent risk factor in liver cancer affecting overall survival (OS, HR 2.43, 95% IC 1.07-5.54, P = 0.0286). Besides, Kaplan-Meier analysis was performed on HCC patients in MSKCC cohort, ARID1A statue resulted in significantly shorter OS (median, 12.2 vs 21.43 months; HR 2.5; P = 0.0092). Conclusions: The results indicated that ARID1A gene mutation was a poor prognostic factor in hepatocellular carcinoma, and these mutational states were associated with higher TMB level, which might be a potential positive biomarker of immunotherapy.

ST2 as checkpoint target for colorectal cancer immunotherapy.

Immune checkpoint blockade immunotherapy delivers promising clinical results in colorectal cancer (CRC). However, only a fraction of cancer patients develop durable responses. The tumor microenvironment (TME) negatively impacts tumor immunity and subsequently clinical outcomes. Therefore, there is a need to identify other checkpoint targets associated with the TME. Early-onset factors secreted by stromal cells as well as tumor cells often help recruit immune cells to the TME, among which are alarmins such as IL-33. The only known receptor for IL-33 is stimulation 2 (ST2). Here we demonstrated that high ST2 expression is associated with poor survival and is correlated with low CD8+ T cell cytotoxicity in CRC patients. ST2 is particularly expressed in tumor-associated macrophages (TAMs). In preclinical models of CRC, we demonstrated that ST2-expressing TAMs (ST2+ TAMs) were recruited into the tumor via CXCR3 expression and exacerbated the immunosuppressive TME; and that combination of ST2 depletion using ST2-KO mice with anti-programmed death 1 treatment resulted in profound growth inhibition of CRC. Finally, using the IL-33trap fusion protein, we suppressed CRC tumor growth and decreased tumor-infiltrating ST2+ TAMs. Together, our findings suggest that ST2 could serve as a potential checkpoint target for CRC immunotherapy.

A vaccine-based nanosystem for initiating innate immunity and improving tumor immunotherapy

The unsatisfactory response rate of immune checkpoint blockade (ICB) immunotherapy severely limits its clinical application as a tumor therapy. Here, we generate a vaccine-based nanosystem by integrating siRNA for Cd274 into the commercial human papillomavirus (HPV) L1 (HPV16 L1) protein. This nanosystem has good biosafety and enhances the therapeutic response rate of anti-tumor immunotherapy. The HPV16 L1 protein activates innate immunity through the type I interferon pathway and exhibits an efficient anti-cancer effect when cooperating with ICB therapy. For both resectable and unresectable breast tumors, the nanosystem decreases 71% tumor recurrence and extends progression-free survival by 67%. Most importantly, the nanosystem successfully induces high response rates in various genetically modified breast cancer models with different antigen loads. The strong immune stimulation elicited by this vaccine-based nanosystem might constitute an approach to significantly improve current ICB immunotherapy.

Immune-related long noncoding RNA signature for predicting survival and immune checkpoint blockade in hepatocellular carcinoma.

Long noncoding RNAs (lncRNAs) show multiple functions, including immune response. Recently, the immune-related lncRNAs have been reported in some cancers. We first investigated the immune-related lncRNA signature as a potential target in hepatocellular carcinoma (HCC) survival. The training set (n = 368) and the independent external validation cohort (n = 115) were used. Immune genes and lncRNAs coexpression were constructed to identify immune-related lncRNAs. Cox regression analyses were perfumed to establish the immune-related lncRNA signature. Regulatory roles of this signature on cancer pathways and the immunologic features were investigated. The correlation between immune checkpoint inhibitors and this signature was examined. In this study, the immune-related lncRNA signature was identified in HCC, which could stratify patients into high- and low-risk groups. This immune-related lncRNA signature was correlated with disease progression and worse survival and was an independent prognostic biomarker. Our immune-related lncRNA signature was still a powerful tool in predicting survival in each stratum of age, gender, and tumor stage. This signature mediated cell cycle, glycolysis, DNA repair, mammalian target of rapamycin signaling, and immunologic characteristics (i.e., natural killer cells vs. Th1 cells down, etc). This signature was associated with immune cell infiltration (i.e., macrophages M0, Tregs, CD4 memory T cells, and macrophages M1, etc.,) and immune checkpoint blockade (ICB) immunotherapy-related molecules (i.e., PD-L1, PD-L2, and IDO1). Our findings suggested that the immune-related lncRNA signature had an important value for survival prediction and may have the potential to measure the response to ICB immunotherapy. This signature may guide the selection of the immunotherapy for HCC.

IL36 Cooperates With Anti-CTLA-4 mAbs to Facilitate Antitumor Immune Responses.

Despite the great impact on long-term survival of some cancer patients, the immune checkpoint blockade (ICB) therapy is limited by its low response rates for most cancers. There is a pressing need for novel combination immunotherapies that overcome the resistance to current ICB therapies. Cytokines play a pivotal role in tumor immunotherapy by helping initiating and driving antitumor immune responses. Here, we demonstrated that, besides conventional CD4+ and CD8+ T cells, IL36 surprisingly increased the number of tumor-infiltrating regulatory T (Treg) cells in vivo and enhanced proliferation of Tregs in vitro. Administration of CTLA-4 monoclonal antibodies (mAbs) strongly enhanced IL36-stimulated antitumor activities through depletion of Tregs. In addition, a cancer gene therapy using the IL36-loaded nanoparticles in combination with CTLA-4 mAbs additively reduced lung metastasis of breast tumor cells. We further showed that the combined therapy of CTLA-4 mAbs and IL36 led to an increase in proliferation and IFN-γ production by CD4+ and CD8+ T cells when compared to single therapy with CTLA-4 mAbs or IL36. Collectively, our findings demonstrated a new combination therapy that could improve the clinical response to ICB immunotherapy for cancer.

Abstract B06: Immune inhibitory receptors restrain hyperactivated effector T cells in the tumor microenvironment

Abstract The immune checkpoint blockade (ICB) immunotherapy of cancer has prolonged overall survival for some patients; however, the response rates are still low. Rational design of combination therapy targeting multiple immune checkpoint inhibitors promises to significantly improve the current ICB therapy. TIM-3 and LAG3 are highly expressed in the tumoral-infiltrating lymphocytes (TIL) and monoclonal antibodies targeting these immune inhibitors have been subjected to intensive clinical development. However, the underlying mechanisms are not fully understood. In order to dissect the mechanisms, we first systematically examined Tim-3 expression in immune cells in mouse tumors. We found Tim-3 was expressed in large portions of Treg, CD4, CD8 T cells, DC1, M1, and MDSC. Administration of a none-depleting Tim-3 antibody alone did not affect tumor progress, but combination treatment with Tim-3 and PD-1 mAbs resulted in a synergistic antitumor efficacy. Mechanistically, treatment with either Tim-3 mAbs or PD-1/Tim-3 mAbs led to a decrease of Treg in the tumor microenvironment (TME). In addition, Tim-3 mAbs and PD-1 mAbs either alone or synergistically increased IFN-γ and granzymes production by CD4+ and CD8+ TIL. Interestingly, combined treatment with Tim-3 and PD-1 mAbs greatly increased the expression of Lag3 in TIL, suggesting induction of hyperactivated effector T cells is associated with increased level of checkpoint inhibitory molecules. We further found that the antitumor efficacy with triple combination of PD-1, Tim-3, and Lag3 mAbs was much greater than double combination. Our data demonstrated that checkpoint inhibitors are genetically encoded to control the graded activation of effector T cells and simultaneous blockade of several inhibitors is necessary to fully unleash the power of immunotherapy of cancer. Citation Format: Binfeng Lu, Min Yang, Wenwen Du, Wensi Zhai, Runzi Sun, Cuihua Yue, Jingting Jiang. Immune inhibitory receptors restrain hyperactivated effector T cells in the tumor microenvironment [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B06.

Abstract IA15: Vascular reprogramming for enhancing cancer immunotherapy

Abstract Immune checkpoint blockade can reinvigorate the tumor-antagonizing functions of T cells and be potentially curative, but the majority of the tumors are either refractory or become resistant to the treatment. Among various parameters, the lack of pre-existing T-cell infiltrates may determine tumor refractoriness to immune checkpoint blockade and other cancer immunotherapies. Increasing data indicate that angiogenic blood vessels can limit the infiltration and functionality of T cells in tumors. For example, high intratumoral VEGFA levels make the tumor blood vessels dysfunctional and poorly permissive to T-cell extravasation, in part through the downregulation of T-cell adhesion molecules on the vascular endothelium. Besides VEGFA, angiopoietin-2 (ANGPT2) also induces abnormal tumor angiogenesis. Accordingly, combined blockade of VEGFA and ANGPT2 reprograms the tumor blood vessels to a form that is conducive to improved T-cell activation and trafficking and enhances tumor response to both immune checkpoint blockade (anti-PD-1) and agonistic CD40 antibodies in several genetically defined mouse cancer models. In my lecture I will discuss the applications, prospects, and current limitations of antiangiogenic immunotherapies. Citation Format: Michele De Palma. Vascular reprogramming for enhancing cancer immunotherapy [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr IA15.

Abstract No. 712 Sequential magnetic resonance imaging image-guided local immune checkpoint blockade immunotherapy using multifunctional carriers with cabazitaxel chemotherapy for the treatment of prostate cancer

Abstract No. 712 Sequential magnetic resonance imaging image-guided local immune checkpoint blockade immunotherapy using multifunctional carriers with cabazitaxel chemotherapy for the treatment of prostate cancer

Checkpoint molecules coordinately restrain hyperactivated effector T cells in the tumor microenvironment

ABSTRACT The immune checkpoint blockade (ICB) immunotherapy has prolonged overall survival for cancer patients but the response rates are low. The resistance to ICB is likely due to compensatory upregulation of additional immune inhibitory molecules. In this study, we first systematically examined Tim-3 expression in immune cells in mouse tumors and found that Tim-3 was specifically up-regulated in a large number of Treg, conventional CD4+, CD8+ T cells, dendritic cell 1 (DC1), and macrophage 1 (M1) in the tumor microenvironment (TME). Interestingly, Tim-3+ T cells in the TME were phenotypically effector but not “exhausted” T cells because Tim-3+ PD-1+ CD8+ T cells had a higher number of mitochondria, greater levels of glycolysis, and higher tumor-specific cytolytic activities compared to Tim-3− PD-1− CD8+ T cells. The combination treatment with Tim-3 and PD-1 mAbs resulted in a synergistic antitumor activity but also increased the expression of Lag-3 and GITR in TIL, demonstrating cross-regulation between multiple checkpoint molecules. Furthermore, we found that the antitumor efficacy with triple combination of Tim-3, PD-1, and Lag3 mAbs was much greater than any two antibodies. Mechanistically, we demonstrated that simultaneous targeting of Tim-3, PD-1, and Lag-3 cooperatively increased the levels of granzyme B and tumor-specific cytolytic activities of CD8+ TIL. Our data indicate that multiple checkpoint molecules are coordinately upregulated to inhibit the function of hyperactivated T cells in the TME and requirement for the simultaneous blockade of PD-1, Tim-3 and Lag3 for cancer treatment.

Listeria-based hepatocellular carcinoma vaccine facilitates anti-PD-1 therapy by regulating macrophage polarization.

Recently, patients with advanced cancers have been benefited greatly from immune checkpoint blockade immunotherapy. However, immune checkpoint blockade is still suboptimal in HCC treatment and more immune modifications are needed to achieve an efficient therapeutic goal. Here, we investigated the combined administration of a Listeria-based HCC vaccine, Lmdd-MPFG, and the anti-PD-1 immune checkpoint blockade antibody. We found that Lmdd-MPFG promoted the expression of PD-L1 in HCC cells but resensitized the tumor local T cell to respond to the anti-PD-1 immunotherapy. Mechanistically, the Lmdd-MPFG vaccine activates the NF-κB pathway in the tumor-associated macrophages (TAMs) through the TLR2 and MyD88 pathway, and recruits p62 to activate the autophagy pathway. The overall effect is skewing the TAMs from M2-polarized TAMs into the M1-polarized TAMs. Most importantly, it skewed the cytokine profiles into antitumor one in the tumor microenvironment (TME). This change restores the T-cell reactivity to the anti-PD-1 blockade. Our results suggested that Lmdd-MPFG combined with PD-1 blockade exerted synergistic antitumor effects through modifying TAMs in the TME and removing T-cell inhibitory signals, thereby providing a new potential strategy for HCC treatment.

Immunoglobulin somatic hypermutation has clinical impact in DLBCL and potential implications for immune checkpoint blockade and neoantigen-based immunotherapies

BackgroundDiffuse large B-cell lymphoma (DLBCL) harbors somatic hypermutation (SHM) in the immunoglobulin heavy chain and light chain variable region genes, IGHV and IGK/LV. Recent studies have revealed that IGV SHM creates neoantigens that activate T-cell responses against B-cell lymphoma.MethodsTo determine the clinical relevance of IGV SHM in DLBCL treated with standard immunochemotherapy, we performed next-generation sequencing of the immunoglobulin variable regions and complementarity determining region 3 (CDR3) for 378 patients with de novo DLBCL. The prognostic effects of IGV SHM and ongoing SHM or intra-clonal heterogeneity were analyzed in the training (192 patients), validation (186 patients), and overall DLBCL cohorts. To gain mechanistic insight, we analyzed the predicted IG-derived neoantigens’ immunogenicity potential, determined by the major histocompatibility complex-binding affinity and the frequency-of-occurrence of T cell-exposed motifs (TCEMs) in a TCEM repertoire derived from human proteome, microbiome, and pathogen databases. Furthermore, IGV SHM was correlated with molecular characteristics of DLBCL and PD-1/L1 expression in the tumor microenvironment assessed by fluorescent multiplex immunohistochemistry.ResultsSHM was commonly found in IGHV and less frequently in IGK/LV. High levels of clonal IGHV SHM (SHMhigh) were associated with prolonged overall survival in DLBCL patients, particularly those without BCL2 or MYC translocation. In contrast, long heavy chain CDR3 length, the presence of IGHV ongoing SHM in DLBCL, and high clonal IGK/LV SHM in germinal center B-cell–like (GCB)-DLBCL were associated with poor prognosis. These prognostic effects were significant in both the training and validation sets. By prediction, the SHMhigh groups harbored more potentially immune-stimulatory neoantigens with high binding affinity and rare TCEMs. PD-1/L1 expression in CD8+ T cells was significantly lower in IGHV SHMhigh than in SHMlow patients with activated B-cell–like DLBCL, whereas PD-1 expression in CD4+ T cells and PD-L1 expression in natural killer cells were higher in IGK/LV SHMhigh than in SHMlow patients with GCB-DLBCL. PD-L1/L2 (9p24.1) amplification was associated with high IGHV SHM and ongoing SHM.ConclusionsThese results show for the first time that IGV SHMhigh and ongoing SHM have prognostic effects in DLBCL and potential implications for PD-1/PD-L1 blockade and neoantigen-based immunotherapies.

15-PGDH regulated PD-1/PD-L1 immune checkpoint blockade immunotherapy in colon cancer is a TNF-α dependent phenomenon

15-PGDH regulated PD-1/PD-L1 immune checkpoint blockade immunotherapy in colon cancer is a TNF-α dependent phenomenon