Antitumor T-cell Immunity Research Articles

Durable Suppression of Acquired MEK Inhibitor Resistance in Cancer by Sequestering MEK from ERK and Promoting Antitumor T-cell Immunity.

MAPK targeting in cancer often fails due to MAPK reactivation. MEK inhibitor (MEKi) monotherapy provides limited clinical benefits but may serve as a foundation for combination therapies. Here, we showed that combining a type II RAF inhibitor (RAFi) with an allosteric MEKi durably prevents and overcomes acquired resistance among cancers with KRAS, NRAS, NF1, BRAF non-V600, and BRAF V600 mutations. Tumor cell-intrinsically, type II RAFi plus MEKi sequester MEK in RAF complexes, reduce MEK/MEK dimerization, and uncouple MEK from ERK in acquired-resistant tumor subpopulations. Immunologically, this combination expands memory and activated/exhausted CD8+ T cells, and durable tumor regression elicited by this combination requires CD8+ T cells, which can be reinvigorated by anti-PD-L1 therapy. Whereas MEKi reduces dominant intratumoral T-cell clones, type II RAFi cotreatment reverses this effect and promotes T-cell clonotypic expansion. These findings rationalize the clinical development of type II RAFi plus MEKi and their further combination with PD-1/L1-targeted therapy. SIGNIFICANCE: Type I RAFi + MEKi are indicated only in certain BRAF V600MUT cancers. In contrast, type II RAFi + MEKi are durably active against acquired MEKi resistance across broad cancer indications, which reveals exquisite MAPK addiction. Allosteric modulation of MAPK protein/protein interactions and temporal preservation of intratumoral CD8+ T cells are mechanisms that may be further exploited.This article is highlighted in the In This Issue feature, p. 521.

A Pilot Study of Galunisertib plus Stereotactic Body Radiotherapy in Patients with Advanced Hepatocellular Carcinoma.

TGFβ is a pleiotropic cytokine with immunosuppressive activity. In preclinical models, blockade of TGFβ enhances the activity of radiation and invokes T-cell antitumor immunity. Here, we combined galunisertib, an oral TGFβ inhibitor, with stereotactic body radiotherapy (SBRT) in patients with advanced hepatocellular carcinoma (HCC) and assessed safety, efficacy, and immunologic correlatives. Patients (n = 15) with advanced HCC who progressed on, were intolerant of, or refused sorafenib were treated with galunisertib (150 mg orally twice a day) on days 1 to 14 of each 28-day cycle. A single dose of SBRT (18-Gy) was delivered between days 15 to 28 of cycle 1. Site of index lesions treated with SBRT included liver (9 patients), lymph node (4 patients), and lung (2 patients). Blood for high-dimensional single cell profiling was collected. The most common treatment-related adverse events were fatigue (53%), abdominal pain (46.6%), nausea (40%), and increased alkaline phosphatase (40%). There were two instances of grade 2 alkaline phosphatase increase and two instances of grade 2 bilirubin increase. One patient developed grade 3 achalasia, possibly related to treatment. Two patients achieved a partial response. Treatment with galunisertib was associated with a decrease in the frequency of activated T regulatory cells in the blood. Distinct peripheral blood leukocyte populations detected at baseline distinguished progressors from nonprogressors. Nonprogressors also had increased CD8+PD-1+TIGIT+ T cells in the blood after treatment. We found galunisertib combined with SBRT to be well tolerated and associated with antitumor activity in patients with HCC. Pre- and posttreatment immune profiling of the blood was able to distinguish patients with progression versus nonprogression.

Antitumor T-cell Immunity Contributes to Pancreatic Cancer Immune Resistance.

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer death in the United States. Pancreatic tumors are minimally infiltrated by T cells and are largely refractory to immunotherapy. Accordingly, the role of T-cell immunity in pancreatic cancer has been somewhat overlooked. Here, we hypothesized that immune resistance in pancreatic cancer was induced in response to antitumor T-cell immune responses and that understanding how pancreatic tumors respond to immune attack may facilitate the development of more effective therapeutic strategies. We now provide evidence that T-cell-dependent host immune responses induce a PDAC-derived myeloid mimicry phenomenon and stimulate immune resistance. Three KPC mouse models of pancreatic cancer were used: the mT3-2D (Kras+/LSL-G12D; Trp53+/LSL-R172H; Pdx1-Cre) subcutaneous and orthotopic models, as well as the KP1 (p48-CRE/LSL-Kras/Trp53 flox/flox ) subcutaneous model. KPC cancer cells were grown in immunocompetent and immunodeficient C57BL/6 mice and analyzed to determine the impact of adaptive immunity on malignant epithelial cells, as well as on whole tumors. We found that induced T-cell antitumor immunity, via signal transducer and activator of transcription 1 (STAT1), stimulated malignant epithelial pancreatic cells to induce the expression of genes typically expressed by myeloid cells and altered intratumoral immunosuppressive myeloid cell profiles. Targeting the Janus Kinase (JAK)/STAT signaling pathway using the FDA-approved drug ruxolitinib overcame these tumor-protective responses and improved anti-PD-1 therapeutic efficacy. These findings provide future directions for treatments that specifically disable this mechanism of resistance in PDAC.

Boosting anti-PD-1 therapy with metformin-loaded macrophage-derived microparticles

The main challenges for programmed cell death 1(PD-1)/PD-1 ligand (PD-L1) checkpoint blockade lie in a lack of sufficient T cell infiltration, tumor immunosuppressive microenvironment, and the inadequate tumor accumulation and penetration of anti-PD-1/PD-L1 antibody. Resetting tumor-associated macrophages (TAMs) is a promising strategy to enhance T-cell antitumor immunity and ameliorate tumor immunosuppression. Here, mannose-modified macrophage-derived microparticles (Man-MPs) loading metformin (Met@Man-MPs) are developed to efficiently target to M2-like TAMs to repolarize into M1-like phenotype. Met@Man-MPs-reset TAMs remodel the tumor immune microenvironment by increasing the recruitment of CD8+ T cells into tumor tissues and decreasing immunosuppressive infiltration of myeloid-derived suppressor cells and regulatory T cells. More importantly, the collagen-degrading capacity of Man-MPs contributes to the infiltration of CD8+ T cells into tumor interiors and enhances tumor accumulation and penetration of anti-PD-1 antibody. These unique features of Met@Man-MPs contribute to boost anti-PD-1 antibody therapy, improving anticancer efficacy and long-term memory immunity after combination treatment. Our results support Met@Man-MPs as a potential drug to improve tumor resistance to anti-PD-1 therapy.

Low-Dose JAK3-Inhibition Improves Anti-Tumor T-Cell Immunity and Immunotherapy Efficacy

Terminal T-cell exhaustion poses a significant barrier to effective anti-cancer immunotherapy efficacy with current drugs aimed at reversing exhaustion being limited. Recent investigations into the molecular drivers of T-cell exhaustion have led to the identification of chronic IL-2 receptor (IL-2R) – STAT5 pathway signaling in mediating T-cell exhaustion. We targeted the key downstream IL-2R-intermediate Janus kinase (JAK) 3 using a clinically relevant highly specific JAK3-inhibitor (JAK3i; PF-06651600) which potently inhibited STAT5-phosphorylation in vitro. Whereas pulsed high-dose JAK3i administration inhibited anti-tumor T-cell immunity, low-dose chronic JAK3i significantly improved T-cell responses and decreased tumor load in mouse models of solid cancer. Low-dose JAK3i combined with cellular and peptide vaccine strategies further decreased tumor load compared to both monotherapies alone. Collectively, these results identify JAK3 as a novel and promising target for combination immunotherapy.

IGFBP2 promotes tumor progression by inducing alternative polarization of macrophages in pancreatic ductal adenocarcinoma through the STAT3 pathway.

Tumor-associated macrophages (TAMs) represent the M2-like phenotype with potent immunosuppressive activity, and play a pro-tumor role in pancreatic ductal adenocarcinoma (PDAC) biology. In this study, we investigated the role of the insulin-like growth factor binding protein 2 (IGFBP2) as a determinant of TAM polarity. Clinical data revealed that the levels of IGFBP2 correlated with M2 TAMs accumulation and disease progression in human PDAC. In vivo mouse model experiments showed that IGFBP2 promoted an immunosuppressive microenvironment and tumor growth in a macrophage dependent manner. Bioinformatics analysis of PDAC transcriptomes revealed a significant association between IGFBP2 expression and M2 macrophage polarization and signal transducer and activator of transcription 3 (STAT3) activation. Mechanistic investigations demonstrated that IGFBP2 augmented the expression and secretion of IL-10 through STAT3 activation in PDAC cells, which induced TAM polarization toward an M2 phenotype. IGFBP2-polarized M2 macrophages significantly increased Tregs infiltration and impaired antitumor T-cell immunity in a mouse model. Thus, our investigations have illuminated the IGFBP2 signaling pathway that contributes to the macrophage-based immunosuppressive microenvironment in PDAC, suggesting that blocking the IGFBP2 axis constitutes a potential treatment strategy to reset TAM polarization toward an antitumor state in PDAC.

Neoantigen Detection in Postoperative Colorectal Cancer Patients by Next-Generation Sequencing and Liquid Chromatography-Mass Spectrometry

Background/Aims: The new antigens are considered to be the best targets for anti-tumor T-cell immunity and individualized cancer immunotherapy strategies. The aim of this study is to explore tumor-specific neoantigen peptides produced by exon mutations of differentially expressed genes in postoperative colorectal cancer and their bioinformatics characteristics. Methods: The whole-genome sequencing of the tumor and paracancerous tissues and human leukocyte antigen class I (HLA-I) alleles of the tumor tissues was first detected by nextgeneration sequencing (NGS), tumor nascent antigen peptides were then predicted and identified according to exon mutations using liquid chromatography-mass spectrometry (LC-MS), and finally the affinity of nascent peptides with respective HLA I was calculate using NETMHC 4.0 Server. Differentially expressed genes producing neoantigens in colorectal cancer tissues were detected and the relationship between these genes and immune cells was screened through TIMER website. The mutation frequency and type of these genes were explored through CBioPortal website. The relationship between these genes and disease-free survival (DFS) and overall survival (OS) in colorectal cancer patients was explored through GEPIA website. Results: A total of 7 tumor-specific neoantigen peptides were identified from 4 patients, of which 3 showed certain affinity with HLA I. Frame-shift deletion, non frame-shift insertion and non frame-shift deletion were three main mutation types of exons. Most of the above-mentioned genes were differentially expressed in colorectal cancer, and some genes tended to express Individually in colorectal cancer. In addition to the type and amount of immune cells infiltrated in the tumor stroma, the expression intensity of these genes was also correlated with DFS and OS of colorectal cancer patients. Conclusion: The above results suggest that the type and number of tumor-specific neoantigens may be related to DFS and OS in postoperative colorectal cancer patients, and help predict the risk of postoperative recurrence, metastasis and prognosis.

Overcoming primary and acquired resistance to anti-PD-L1 therapy by induction and activation of tumor-residing cDC1s

The ability of cancer cells to ensure T-cell exclusion from the tumor microenvironment is a significant mechanism of resistance to anti-PD-1/PD-L1 therapy. Evidence indicates crucial roles of Batf3-dependent conventional type-1 dendritic cells (cDC1s) for inducing antitumor T-cell immunity; however, strategies to maximize cDC1 engagement remain elusive. Here, using multiple orthotopic tumor mouse models resistant to anti-PD-L1-therapy, we are testing the hypothesis that in situ induction and activation of tumor-residing cDC1s overcomes poor T-cell infiltration. In situ immunomodulation with Flt3L, radiotherapy, and TLR3/CD40 stimulation induces an influx of stem-like Tcf1+ Slamf6+ CD8+ T cells, triggers regression not only of primary, but also untreated distant tumors, and renders tumors responsive to anti-PD-L1 therapy. Furthermore, serial in situ immunomodulation (ISIM) reshapes repertoires of intratumoral T cells, overcomes acquired resistance to anti-PD-L1 therapy, and establishes tumor-specific immunological memory. These findings provide new insights into cDC1 biology as a critical determinant to overcome mechanisms of intratumoral T-cell exclusion.

Bispecific Targeting of PD-1 and PD-L1 Enhances T-cell Activation and Antitumor Immunity.

The programmed cell death protein 1 receptor (PD-1) and programmed death ligand 1 (PD-L1) coinhibitory pathway suppresses T-cell-mediated immunity. We hypothesized that cotargeting of PD-1 and PD-L1 with a bispecific antibody molecule could provide an alternative therapeutic approach, with enhanced antitumor activity, compared with monospecific PD-1 and PD-L1 antibodies. Here, we describe LY3434172, a bispecific IgG1 mAb with ablated Fc immune effector function that targets both human PD-1 and PD-L1. LY3434172 fully inhibited the major inhibitory receptor-ligand interactions in the PD-1 pathway. LY3434172 enhanced functional activation of T cells in vitro compared with the parent anti-PD-1 and anti-PD-L1 antibody combination or respective monotherapies. In mouse tumor models reconstituted with human immune cells, LY3434172 therapy induced dramatic and potent antitumor activity compared with each parent antibody or their combination. Collectively, these results demonstrated the enhanced immunomodulatory (immune blockade) properties of LY3434172, which improved antitumor immune response in preclinical studies, thus supporting its evaluation as a novel bispecific cancer immunotherapy.

CDK4/6 inhibition enhances antitumor efficacy of chemotherapy and immune checkpoint inhibitor combinations in preclinical models and enhances T-cell activation in patients with SCLC receiving chemotherapy.

BackgroundCombination treatment with chemotherapy and immune checkpoint inhibitors (ICIs) has demonstrated meaningful clinical benefit to patients. However, chemotherapy-induced damage to the immune system can potentially diminish the efficacy of chemotherapy/ICI combinations. Trilaciclib, a highly potent, selective and reversible cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor in development to preserve hematopoietic stem and progenitor cells and immune system function during chemotherapy, has demonstrated proof of concept in recent clinical trials. Furthermore, CDK4/6 inhibition has been shown to augment T-cell activation and antitumor immunity in preclinical settings. Therefore, addition of trilaciclib has the potential to further enhance the efficacy of chemotherapy and ICI combinations.MethodsIn murine syngeneic tumor models, a schedule of 3 weekly doses of trilaciclib was combined with chemotherapy/ICI regimens to assess the effect of transient CDK4/6 inhibition on antitumor response and intratumor T-cell proliferation and function. Peripheral T-cell status was also analyzed in patients with small cell lung cancer (SCLC) treated with chemotherapy with or without trilaciclib to gain insights into the effect of transient exposure of trilaciclib on T-cell activation.ResultsPreclinically, the addition of trilaciclib to chemotherapy/ICI regimens enhanced antitumor response and overall survival compared with chemotherapy and ICI combinations alone. This effect is associated with the modulation of the proliferation and composition of T-cell subsets in the tumor microenvironment and increased effector function. Transient exposure of trilaciclib in patients with SCLC during chemotherapy treatment both preserved and increased peripheral lymphocyte counts and enhanced T-cell activation, suggesting that trilaciclib not only preserved but also enhanced immune system function.ConclusionsTransient CDK4/6 inhibition by trilaciclib was sufficient to enhance and prolong the duration of the antitumor response by chemotherapy/ICI combinations, suggesting a role for the transient cell cycle arrest of tumor immune infiltrates in remodeling the tumor microenvironment. These results provide a rationale for combining trilaciclib with chemotherapy/ICI regimens to improve antitumor efficacy in patients with cancer.

The PD-1/PD-L1-Checkpoint Restrains T cell Immunity in Tumor-Draining Lymph Nodes

PD-1/PD-L1-checkpoint blockade therapy is generally thought to relieve tumor cell-mediated suppression in the tumor microenvironment but PD-L1 is also expressed on non-tumor macrophages and conventional dendritic cells (cDCs). Here we show in mouse tumor models that tumor-draining lymph nodes (TDLNs) are enriched for tumor-specific PD-1+ Tcells which closely associate with PD-L1+ cDCs. TDLN-targeted PD-L1-blockade induces enhanced anti-tumor Tcell immunity by seeding the tumor site with progenitor-exhausted Tcells, resulting in improved tumor control. Moreover, we show that abundant PD-1/PD-L1-interactions in TDLNs of nonmetastatic melanoma patients, but not those in corresponding tumors, associate with early distant disease recurrence. These findings point at a critical role for PD-L1 expression in TDLNs in governing systemic anti-tumor immunity, identifying high-risk patient groups amendable to adjuvant PD-1/PD-L1-blockade therapy.

Adoptive T Cell Therapy Targeting Different Gene Products Reveals Diverse and Context-Dependent Immune Evasion in Melanoma

Tumor immune escape limits durable responses to Tcell therapy. Here, we examined how regulation and function of gene products that provide the target epitopes for CD8+ Tcell anti-tumor immunity influence therapeutic efficacy and resistance. We used a CRISPR-Cas9-based method (CRISPitope) in syngeneic melanoma models to fuse the same model CD8+ Tcell epitope to the C-termini of different endogenous gene products. Targeting melanosomal proteins or oncogenic CDK4R24C (Cyclin-dependent kinase 4) by adoptive cell transfer (ACT) of the same epitope-specific CD8+ Tcells revealed diverse genetic and non-genetic immune escape mechanisms. ACT directed against melanosomal proteins, but not CDK4R24C, promoted melanoma dedifferentiation, and increased myeloid cell infiltration. CDK4R24C antigen persistence was associated with an interferon-high and T-cell-rich tumor microenvironment, allowing for immune checkpoint inhibition as salvage therapy. Thus, the choice of target antigen determines the phenotype and immune contexture of recurrent melanomas, with implications to the design of cancer immunotherapies.

Intratumoral TIGIT+ CD8+ T-cell infiltration determines poor prognosis and immune evasion in patients with muscle-invasive bladder cancer

BackgroundT-cell immunoglobulin and ITIM domain (TIGIT) is identified as a novel checkpoint receptor that can facilitate immune escape via mediating T-cell exhaustion in tumors. However, the clinical significance and immune...

Abstract A10: Constitutive HIF activity enhances T-cell antitumor immunity and memory T-cell formation in the murine adoptive cell therapy model

Abstract Purpose: To determine if unrestrained hypoxia inducible factor (HIF) activity in CD8 T cells improves antitumor response. Methods: CD8 T cells were isolated from von Hippel Lindau (VHL)-deficient (VHL KO) mice, which have unrepressed HIF1 and HIF2 activity, as well as from VHL/HIF1/HIF2 triple-deficient (TKO) and WT mice. Following in vitro activation, T cells were transferred to melanoma (B16) tumor-bearing mice and monitored for tumor progression and survival. In other studies, activated VHL KO and TKO CD8 cells were mixed with WT CD8 cells and transferred to B16 or adenocarcinoma (MC38) tumor-bearing mice; after 7-10 days, donor T cells were analyzed from tumors, spleens, and draining lymph nodes (LN). Results: Single transfer of VHL KO CD8 T cells to B16 tumor-bearing mice resulted in delayed tumor growth and prolonged survival compared to transfer of CD8 T cells from TKO or WT donors. Co-transfer of VHL KO cells with WT cells into B16 tumor-bearing mice resulted in superior accumulation of VHL KO cells in all tissues including tumors. In contrast, mixed transfer of TKO cells with WT cells to B16 tumor-bearing mice resulted in poorer accumulation of TKO cells in all tissues including tumors. VHL KO tumor-infiltrating lymphocytes (TILs) had superior expression of tissue resident memory (TRM) phenotype markers CD103 and CD69 compared to WT and TKO TILs. Similarly in the MC38 tumor model, VHL KO cells showed improved accumulation in all tissues compared to WT cells. Conclusions: Here we demonstrate that VHL deletion in CD8 T cells results in superior efficacy in delaying tumor growth and improving recipient survival, greater accumulation in multiple solid tumor models, and increased development of the TRM phenotype. Further, TKO recipients demonstrated increased tumor growth, reduced survival, reduced TIL numbers, and absence of TRM phenotype following adoptive transfer, confirming the HIF dependency of the VHL-deletion phenotype. Taken together, these data demonstrate that T cells with constitutive HIF activity provide a more robust antitumor response. Therefore, manipulation of HIF regulation could offer new tools for enhanced T-cell efficacy in adoptive cellular therapy for solid tumors. Citation Format: Colette R. Lauhan, Deborah Witherden, Ilkka Liikanan, Ananda Goldrath. Constitutive HIF activity enhances T-cell antitumor immunity and memory T-cell formation in the murine adoptive cell therapy model [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr A10.

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.

Case report: Minimal change disease and acute interstitial nephritis in a patient with Hodgkin’s lymphoma treated with nivolumab

Programmed cell death receptor-1 blocking antibodies and cytotoxic T-lymphocyte–associated antigen-4 blocking antibodies are referred to as checkpoint inhibitors and are used in cancer immunotherapy. While enhancing T-cell antitumor immunity, checkpoint inhibitors can also cause immune-mediated nephrotoxicities, manifesting mostly in acute kidney injury. Cytotoxic T-lymphocyte–associated antigen-4 blockade was associated with acute interstitial nephritis with variable degrees of podocyte effacement, minimal change disease, and membranous nephropathy. Conversely, programmed cell death receptor-1 blockade has mostly been associated with acute interstitial nephritis, with or without various glomerular diseases. In particular, cases of minimal change disease were reported with programmed cell death receptor-1 blockade, including two cases of minimal change disease reported in Hodgkin’s lymphoma and one with mesothelioma, in addition to one case of focal segmental glomerulosclerosis after treatment of renal cell carcinoma. We report a case of acute interstitial nephritis and minimal change disease in a patient with Hodgkin’s lymphoma treated with nivolumab and discuss pathophysiological hypotheses. The association of minimal change disease with Hodgkin’s lymphoma is well-recognized and may be related to c-mip protein and/or CD80. The checkpoint pathway likely triggers the auto-immune, T-cell-mediated, minimal change disease associated with Hodgkin’s lymphoma; however, this pathogenic process may also involve a programmed cell death receptor-1– fyn-c-mip interaction or a PD-L1–CD80 cross-talk at both T-cell and podocyte level.

Sa1466 EUS HAS THE POTENTIAL TO EVALUATE MEMBERS OF THE TUMOR NECROSIS FACTOR (TNF) SUPERFAMILY AND IDENTIFY DRUG TARGETS ON AN INDIVIDUAL PDAC PATIENT BASIS TO GUIDE PRECISION IMMUNE-ONCOLOGY ELIGIBILITY

The FDA has approved use of the programmed cell death-1 (PD-1) inhibitor, pembrolizumab, in MSI-High solid tumors. This is a rare event among pancreas ductal adenocarcinoma (PDAC) patients, occurring at a frequency of 0.8%. In order to decipher if other cancer immunotherapy targets are potential therapies for PDAC patients, the Tumor Necrosis Factor (TNF) Receptor Superfamily has gained prominence, due to its ability to activate antitumor T-cell immunity. Members include CD70, TNFSF4 (OX-40L) and TNFRSF9 (41BB). It is important to develop strategies to aid patient selection criteria to guide therapeutic decision-making for clinical trials. We sought to determine if EUS fine needle biopsy (FNB) treatment naïve PDAC specimens are suitable to evaluate the TNF Superfamily, and in turn identify potential targets on an individual patient basis. The cohort of 13 EUS FNB patient specimens, 7 of whom with ≥ stage III disease, a CA19-9 level of 227.5 (IQR 58-605) U/ml and overall mortality of 77% at 22.2 (IQR 13.4-36.1) months was evaluated by the Nanostring nCounter® PanCancer Immune Profiling Panel. This is a highly multiplexed mRNA gene expression panel designed to quantitate the expression of 770 genes. A ≥ 2-fold change in expression when compared to pancreas control tissue was deemed to be reflective of altered expression. The digital mRNA profiling panel revealed that 44.8% and 10% of evaluated genes had either increased or reduced expression, when compared to normal pancreas controls. Of the 30 TNF Superfamily gene members evaluated, 17 (56.7%) and 1 (3.3%) were up and downregulated in PDAC and 4 (13.3%) were each up and down regulated in surgical resection chronic pancreatitis specimens (n=3), respectively. (Figure 1) TNFRSF10C (alias TRAILR3) and TNFRSF11B (alias Osteoprotegerin) expressions were elevated in 12 (92.3%) PDAC specimens x12.2-fold (range x1.8 – x36.2 fold) and x6.5-fold (range x1.8 – x40.9 fold), respectively. CD70, an immune checkpoint, had a tumor-restricted expression pattern and was upregulated in 10 (77%) PDAC patients (x3.2-fold) but downregulated in chronic pancreatitis (x-4.23-fold). (Figure 2) EUS has a central role in guiding precision immune-oncology eligibility for clinical care and clinical trials. Using digital mRNA profiling, CD70 had a tumor-restricted expression pattern and was identified in 77% of PDAC patient specimens. Therefore, this suggests that such patients may be sensitive to monoclonal antibody therapy that targets and neutralizes CD70.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Remodeling Translation Primes CD8+ T-cell Antitumor Immunity.

The requisites for protein translation in T cells are poorly understood and how translation shapes the antitumor efficacy of T cells is unknown. Here we demonstrated that IL15-conditioned T cells were primed by the metabolic energy sensor AMP-activated protein kinase to undergo diminished translation relative to effector T cells. However, we showed that IL15-conditioned T cells exhibited a remarkable capacity to enhance their protein translation in tumors, which effector T cells were unable to duplicate. Studying the modulation of translation for applications in cancer immunotherapy revealed that direct ex vivo pharmacologic inhibition of translation elongation primed robust T-cell antitumor immunity. Our work elucidates that altering protein translation in CD8+ T cells can shape their antitumor capability.

Resveratrol targets PD-L1 glycosylation and dimerization to enhance antitumor T-cell immunity.

New strategies to block the immune evasion activity of programmed death ligand-1 (PD-L1) are urgently needed. When exploring the PD-L1-targeted effects of mechanistically diverse metabolism-targeting drugs, exposure to the dietary polyphenol resveratrol (RSV) revealed its differential capacity to generate a distinct PD-L1 electrophoretic migration pattern. Using biochemical assays, computer-aided docking/molecular dynamics simulations, and fluorescence microscopy, we found that RSV can operate as a direct inhibitor of glyco-PD-L1-processing enzymes (α-glucosidase/α-mannosidase) that modulate N-linked glycan decoration of PD-L1, thereby promoting the endoplasmic reticulum retention of a mannose-rich, abnormally glycosylated form of PD-L1. RSV was also predicted to interact with the inner surface of PD-L1 involved in the interaction with PD-1, almost perfectly occupying the target space of the small compound BMS-202 that binds to and induces dimerization of PD-L1. The ability of RSV to directly target PD-L1 interferes with its stability and trafficking, ultimately impeding its targeting to the cancer cell plasma membrane. Impedance-based real-time cell analysis (xCELLigence) showed that cytotoxic T-lymphocyte activity was notably exacerbated when cancer cells were previously exposed to RSV. This unforeseen immunomodulating mechanism of RSV might illuminate new approaches to restore T-cell function by targeting the PD-1/PD-L1 immunologic checkpoint with natural polyphenols.

Ubi Maior Minor Cessat.

This article is a tribute to Eli Sercarz and draws on his proposal of a hierarchical order of T-cell determinants in antigen presentation and T-cell activation. Here I revisit the concept of dominance and crypticity in the context of lymphocyte cooperation in the generation of the adaptive immune response, with emphasis on Th-Th cooperation. The remarks made in this article serve as a basis for a reassessment of the unresponsiveness of self-tumor antigens and how to leverage cryptic T-cell determinants operationally to generate antitumor T-cell immunity.