Effect Of Immune Checkpoint Blockade Research Articles

Causal relationships between gut microbiota and programmed cell death protein 1/programmed cell death-ligand 1: A bidirectional Mendelian randomization study.

Multiple clinical studies have indicated that the gut microbiota influences the effects of immune checkpoint blockade (ICB) therapy comprising PD-1/PD-L1 inhibitors, but the causal relationship is unclear. Because of numerous confounders, many microbes related to PD-1/PD-L1 have not been identified. This study aimed to determine the causal relationship between the microbiota and PD-1/PD-L1 and identify possible biomarkers for ICB therapy. We used bidirectional two-sample Mendelian randomization with two different thresholds to explore the potential causal relationship between the microbiota and PD-1/PD-L1 and species-level microbiota GWAS to verify the result. In the primary forward analysis, genus_Holdemanella showed a negative correlation with PD-1 [βIVW = -0.25; 95% CI (-0.43 to -0.07); PFDR = 0.028] and genus_Prevotella9 showed a positive correlation with PD-1 [βIVW = 0.2; 95% CI (0.1 to 0.4); PFDR = 0.027]; order_Rhodospirillales [βIVW = 0.2; 95% CI (0.1 to 0.4); PFDR = 0.044], family_Rhodospirillaceae [βIVW = 0.2; 95% CI (0 to 0.4); PFDR = 0.032], genus_Ruminococcaceae_UCG005 [βIVW = 0.29; 95% CI (0.08 to 0.5); PFDR = 0.028], genus_Ruminococcus_gnavus_group [βIVW = 0.22; 95% CI (0.05 to 0.4); PFDR = 0.029], and genus_Coprococcus_2 [βIVW = 0.4; 95% CI (0.1 to 0.6); PFDR = 0.018] were positively correlated with PD-L1; and phylum_Firmicutes [βIVW = -0.3; 95% CI (-0.4 to -0.1); PFDR = 0.031], family_ClostridialesvadinBB60group [βIVW = -0.31; 95% CI (-0.5 to -0.11), PFDR = 0.008], family_Ruminococcaceae [βIVW = -0.33; 95% CI (-0.58 to -0.07); PFDR = 0.049], and genus_Ruminococcaceae_UCG014 [βIVW = -0.35; 95% CI (-0.57 to -0.13); PFDR = 0.006] were negatively correlated with PD-L1. The one significant species in further analysis was species_Parabacteroides_unclassified [βIVW = 0.2; 95% CI (0-0.4); PFDR = 0.029]. Heterogeneity (P > 0.05) and pleiotropy (P > 0.05) analyses confirmed the robustness of the MR results.

Biodegradable MnO2-based gene-engineered nanocomposites for chemodynamic therapy and enhanced antitumor immunity.

Immune checkpoint blockade (ICB) is emerging as a promising therapeutic approach for clinical treatment against various cancers. However, ICB based monotherapies still suffer from low immune response rate due to the limited and exhausted tumor-infiltrating lymphocytes as well as tumor immunosuppressive microenvironment. In this work, the cell membrane with surface displaying PD-1 proteins (PD1-CM) was prepared for immune checkpoint blockade, which was further combined with multifunctional and biodegradable MnO2 for systematic and robust antitumor therapy. The MnO2-based gene-engineered nanocomposites can catalyze the decomposition of abundant H2O2 in TME to generate O2, which can promote the intratumoral infiltration of T cells, and thus improve the effect of immune checkpoint blockade by PD-1 proteins on PD1-CM. Furthermore, MnO2 in the nanocomposites can be completely degraded into Mn2+, which can catalyze the generation of highly toxic hydroxyl radicals for chemodynamic therapy, thereby further enhancing the therapeutic effect. In addition, the prepared nanocomposites possess the advantages of low cost, easy preparation and good biocompatibility, which are expected to become promising agents for combination immunotherapy.

Identification of a tumour immune barrier in the HCC microenvironment that determines the efficacy of immunotherapy

The tumour microenvironment (TME) is a crucial mediator of cancer progression and therapeutic outcome. The TME subtype correlates with patient response to immunotherapy in multiple cancers. Most previous studies have focused on the role of different cellular components in the TME associated with immunotherapy efficacy. However, the specific structure of the TME and its role in immunotherapy efficacy remain largely unknown. We combined spatial transcriptomics with single-cell RNA-sequencing and multiplexed immunofluorescence to identify the specific spatial structures in the TME that determine the efficacy of immunotherapy in patients with hepatocellular carcinoma (HCC) receiving anti-PD-1 treatment. We identified a tumour immune barrier (TIB) structure, a spatial niche composed of SPP1+ macrophages and cancer-associated fibroblasts (CAFs) located near the tumour boundary, which is associated with the efficacy of immune checkpoint blockade. Furthermore, we dissected ligand‒receptor networks among malignant cells, SPP1+ macrophages, and CAFs; that is, the hypoxic microenvironment promotes SPP1 expression, and SPP1+ macrophages interact with CAFs to stimulate extracellular matrix remodelling and promote TIB structure formation, thereby limiting immune infiltration in the tumour core. Preclinically, the blockade of SPP1 or macrophage-specific deletion of Spp1 in mice led to enhanced efficacy of anti-PD-1 treatment in mouse liver cancer, accompanied by reduced CAF infiltration and increased cytotoxic T-cell infiltration. We identified that the TIB structure formed by the interaction of SPP1+ macrophages and CAFs is related to immunotherapy efficacy. Therefore, disruption of the TIB structure by blocking SPP1 may be considered a relevant therapeutic approach to enhance the therapeutic effect of immune checkpoint blockade in HCC. Only a limited number of patients with hepatocellular carcinoma (HCC) benefit from tumour immunotherapy, which significantly hinders its application. Herein, we used multiomics to identify the spatial structure of the tumour immune barrier (TIB), which is formed by the interaction of SPP1+ macrophages and cancer-associated fibroblasts in the HCC microenvironment. This structure constrains immunotherapy efficacy by limiting immune cell infiltration into malignant regions. Preclinically, we revealed that blocking SPP1 or macrophage-specific deletion of Spp1 in mice could destroy the TIB structure and sensitize HCC cells to immunotherapy. These results provide the first key steps towards finding more effective therapies for HCC and have implications for physicians, scientists, and drug developers in the field of HCC.

A RIPK3-independent role of MLKL in suppressing parthanatos promotes immune evasion in hepatocellular carcinoma

Mixed lineage kinase domain-like (MLKL) is widely accepted as an executioner of necroptosis, in which MLKL mediates necroptotic signaling and triggers cell death in a receptor-interacting protein kinase 3 (RIPK3)-dependent manner. Recently, it is increasingly noted that RIPK3 is intrinsically silenced in hepatocytes, raising a question about the role of MLKL in hepatocellular carcinoma (HCC). This study reports a previously unrecognized role of MLKL in regulating parthanatos, a programmed cell death distinct from necroptosis. In HCC cells with intrinsic RIPK3 deficiency, knockout of MLKL impedes the orthotopic tumor growth, activates the anti-tumor immune response and enhances the therapeutic effect of immune checkpoint blockade in syngeneic HCC tumor models. Mechanistically, MLKL is required for maintaining the endoplasmic reticulum (ER)-mitochondrial Mg2+ dynamics in HCC cells. MLKL deficiency restricts ER Mg2+ release and mitochondrial Mg2+ uptake, leading to ER dysfunction and mitochondrial oxidative stress, which together confer increased susceptibility to metabolic stress-induced parthanatos. Importantly, pharmacological inhibition of poly(ADP-ribose) polymerase to block parthanatos restores the tumor growth and immune evasion in MLKL-knockout HCC tumors. Together, our data demonstrate a new RIPK3-independent role of MLKL in regulating parthanatos and highlight the role of MLKL in facilitating immune evasion in HCC.

Releasing the restraints of Vγ9Vδ2 T-cells in cancer immunotherapy.

Vγ9Vδ2 T-cells are a subset of T-cells with a crucial role in immunosurveillance which can be activated and expanded by multiple means to stimulate effector responses. Little is known about the expression of checkpoint molecules on this cell population and whether the ligation of these molecules can regulate their activity. The aim of this study was to assess the expression of both activatory and inhibitory receptors on Vγ9Vδ2 T-cells to assess potential avenues of regulation to target with immunotherapy. Expression of various activatory and inhibitory receptors was assessed on Vγ9Vδ2 T-cells by flow cytometry following activation and expansion using zoledronic acid (ZA) and Bacillus Calmette-Guérin (BCG). Expression of these markers and production of effector molecules was also examined following co-culture with various tumour cell targets. The effect of immune checkpoint blockade on Vγ9Vδ2 T-cells was also explored. Vγ9Vδ2 T-cells expressed high levels of activatory markers both at baseline and following stimulation. Vγ9Vδ2 T-cells expressed variable levels of inhibitory checkpoint receptors with many being upregulated following stimulation. Expression of these markers is further modulated upon co-culture with tumour cells with changes reflecting activation and effector functions. Despite their high expression of inhibitory receptors when cultured with tumour cells expressing cognate ligands there was no effect on Vδ2+ T-cell cytotoxic capacity or cytokine production with immune checkpoint blockade. Our work suggests the expression of checkpoint receptors present on Vγ9Vδ2 T-cells which may provide a mechanism with the potential to be utilised by tumour cells to subvert Vγ9Vδ2 T-cell cytotoxicity. This work suggests important candidates for blockade by ICI therapy in order to increase the successful use of Vγ9Vδ2 T-cells in immunotherapy.

Immune Checkpoint Inhibitors and Infection: What Is the Interplay?

Immune checkpoint molecules are receptors expressed on immune cells, especially T-cells, which activate immunosuppressive pathways and lead them to a state known as T-cell exhaustion. Immune checkpoint inhibitors (ICIs) constitute a group of specific antibodies that target these molecules, restoring T-cell effector function. Several ICIs have already been approved by the FDA as therapeutic options for certain malignancies. However, evidence in the literature remains unclear regarding the possible risk of infection in patients receiving this treatment. A thorough examination of existing literature was carried out to investigate whether the use of ICIs increases the likelihood of specific infections and to explore the potential beneficial effects of ICIs on the treatment of infections. Our review found most infectious complications are related to immunosuppressive therapy for immune-related adverse events caused by checkpoint blockade. Current evidence shows that ICIs per se do not seem to generally increase the risk of infection, yet they might increase susceptibility to certain infections, such as tuberculosis. On the other hand, reinvigoration of immune responses triggered by ICIs might play a significant role in pathogen clearance, establishing a possible positive impact of ICIs, especially on chronic infectious diseases, such as HIV infection. Data from preclinical models are limited and larger clinical trials are warranted to shed more light on the effect of immune checkpoint blockade on specific pathogens.

Phase Ib/II study of nivolumab combined with palliative radiation therapy for bone metastasis in patients with HER2-negative metastatic breast cancer

Radiation therapy (RT) can enhance the abscopal effect of immune checkpoint blockade. This phase I/II study investigated the efficacy and safety of nivolumab plus RT in HER2-negative metastatic breast cancer requiring palliative RT for bone metastases. Cohort A included luminal-like disease, and cohort B included both luminal-like and triple-negative disease refractory to standard systemic therapy. Patients received 8 Gy single fraction RT for bone metastasis on day 0. Nivolumab was administered on day 1 for each 14-day cycle. In cohort A, endocrine therapy was administered. The primary endpoint was the objective response rate (ORR) of the unirradiated lesions. Cohorts A and B consisted of 18 and 10 patients, respectively. The ORR was 11% (90% CI 4–29%) in cohort A and 0% in cohort B. Disease control rates were 39% (90% CI 23–58%) and 0%. Median progression-free survival was 4.1 months (95% CI 2.1–6.1 months) and 2.0 months (95% CI 1.2–3.7 months). One patient in cohort B experienced a grade 3 adverse event. Palliative RT combined with nivolumab was safe and showed modest anti-tumor activity in cohort A. Further investigations to enhance the anti-tumor effect of endocrine therapy combined with RT plus immune checkpoint blockade are warranted.Trial registration number and date of registration UMIN: UMIN000026046, February 8, 2017; ClinicalTrials.gov: NCT03430479, February 13, 2018; Date of the first registration: June 22, 2017.

Overexpression of SMS in the tumor microenvironment is associated with immunosuppression in hepatocellular carcinoma.

Disorders of polyamine metabolism may contribute to the development of hepatocellular carcinoma (HCC), but the precise mechanism remains unknown. This study reports that spermine synthase (SMS), an enzyme involved in polyamine biosynthesis, is overexpressed in HCC and not associated with hepatitis virus infection in HCC patients. The results of analyzing the clinical data of HCC patients showed that SMS level as a categorical dependent variable was related to clinicopathological features of poor prognosis. Furthermore, the Kaplan-Meier survival analysis and ROC curve indicated that increased SMS level is associated with poor survival rate in HCC and may be a potential biomarker to discriminate HCC tissues. However, SMS overexpression limited the therapeutic effect of immune checkpoint blockade (ICB), which seemed to be related to the immunosuppressive effect of the HCC immune microenvironment formed by higher mRNA transcript levels of immune checkpoints and higher infiltration levels of immunosuppressive cells. In samples with high and low SMS expression, functional enrichment analysis of the differentially expressed genes (DEGs) showed that SMS may be linked to the occurrence and development of HCC by affecting a variety of immune-related pathways, such as Intestinal immune network for IgA production, Fc gamma R-mediated phagocytosis, Antigen processing and presentation, Th1 and Th2 cell differentiation. Subsequently, analysis of the co-expression network of SMS in the liver hepatocellular carcinoma (LIHC) cohort revealed that SMS has a broad impact on multiple important immune- and metabolic-related processes in HCC. In summary, SMS is a promising biomarker to differentiate the prognosis, immune characteristics, and holds promise as a potential target for ICB therapy to improve HCC.

First-in-Class Histone Acetyltransferase (HAT) Activator, YF2, Modulates Immune Evasion in DLBCL, Enhancing the Effects of Immune Checkpoint Blockade

We reported the discovery of YF2, a EP300 (p300) and CREBBP (CBP) HAT activator which demonstrates selective cytotoxicity in HAT-mutated DLBCL cell lines and induces histone acetylation in vitro and in vivo. Recently, we have focused on the role of HAT induction in regulating immune response in DLBCLs. CBP has been shown to function as an enhancer that regulates GC B-cell fate by controlling antigen presentation and terminal differentiation. HAT mutations are linked to reduced MHC-II HLA transcripts due to decreased acetylation at the promoter regions which leads to decreased GC B:T cell entanglement and derangements in the GC reaction. Numerous studies have reported the effect of epigenetic drugs on antigen presentation. This response is caused by disruption of the BLC6/SMRT/HDAC3 repressor complex which co-occupies enhancers in the MHC Class II loci. Previously, we demonstrated YF2 induced p300 mediated acetylation of BCL6; abrogating its activity. More recently, we demonstrated through RNA-seq that prolonged treatment of YF2 upregulated the expression of several MHC Class I-II genes resulting in the upregulation of the immune regulation signaling pathway. Further, treatment with YF2 up-regulated MHC-I and -II expression in a dose dependent manner. In addition to regulating immune response, BCL6 is a master regulator of GC formation. We hypothesize that induction of HATs will modulate immune response in splenic and circulating B and T-cells. Immunized BALB/c mice were treated with saline or 50mg/kg YF2 for 10 days. Spleen and blood samples were analyzed by flow cytometry. We observed a significant reduction in splenic weight, B-cell frequency, and GCs formation in YF2 treated mice. YF2 treatment increased the frequency of mature and transitional B-cells in the spleen. Further, YF2 treatment reduced light zone and increased dark zone cells in the spleen. YF2 treatment also increased the frequency of plasma cells and plasmablast. MHC-I and -II expression was significantly upregulated in YF2 treated mice. YF2 exposure resulted in an increase of PD-L1hi B-cells. Lastly, circulating B-cells showed significant increase in MHC-II expression following YF2 treatment. In splenic T-cells, we observed a reduction in CD4+ helper T-cells and an increase in CD8+ cytotoxic T-cells in YF2 treated mice. YF2 caused a reduction in naïve CD4+ cells and an increase in the frequency of central and effector memory cells Lastly, we examined the frequency of inhibitory molecules PD1, TIGIT, CD226, Lag3, and VISTA. PD-1, TIGIT, and CD226 were upregulated with YF2 treatment in CD4+ cells and CD226 was upregulated in CD8+ cells. Together, these results demonstrate YF2 is able to modulate immune response in B and T-cells. DLBCLs are known to have limited sensitivity to checkpoint blockade with PD-1 and PD-L1 inhibitors due to low PD-L1 and PD-1 expression which is in part driven by HAT mutations and overexpression of BCL6; which regulates PD-L1. We hypothesize that combination treatment of YF2 and PD-1 inhibitor in the immunocompetent syngeneic A20 mouse tumor xenograft model will result in decreased tumorigenicity and improved survival in mice. Xenografted and immunized BALBc mice were treated with saline, YF2, PD-1 inhibitor, or a combination of YF2 and PD-1 inhibitor for 28 days. We observed, a significant reduction in tumor volume in both the PD-1 and combination treated groups. Kaplan-Meier analysis showed an increase in median survival for all treatment with the combination treatment resulting in the greatest increase in median survival vs. control (Fig A). Spatial analysis was performed using the 10x Visium platform and sc-RNA-seq to examine the tumor microenvironment in control and YF2 treated mouse tumor samples (Fig B). We observed a more aggressive phenotype in the untreated tumors as well as an increase in the number of distinct clusters indicating a more heterogenous tumor population. Lastly, PBMCs from patient samples were isolated and treated with YF2. Compared to healthy donor patients, YF2 induced cytotoxicity across various lymphoma subtype. Normal PBMCs were not affected by treatment. Based on the success of YF2 in the preclinical setting, the use of this first-in-class drug for treatment of lymphoma was approved to proceed in clinical studies in patients with relapsed/refractory lymphoma. Patient samples will be collected and analyzed for immune response. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Atezolizumab plus tivozanib for immunologically cold tumor types: theIMMCO-1 trial.

Immune checkpoint inhibitor therapy represents a significant advance in cancer care. The interaction between PD-1 and PD-L1 induces immune tolerance and the inhibition of this interaction is an effective treatment strategy for numerous malignancies. Despite its demonstrated potential, immunotherapy is not clinically effective in immunogenically 'cold' tumors such as pancreatic cancer, prostate cancerand neuroendocrine tumors. Through the inhibition of VEGF, it may be possible to potentiate the effect of immune checkpoint blockade in tumors that have traditionally shown a lack of clinical response to immunotherapy. This signal-seeking, single-arm, prospectiveclinical trial aims to determine the objective response oftivozanib and atezolizumab in advanced immunogenically cold solid tumors. Clinical Trial Registration: NCT05000294 (ClinicalTrials.gov).

Target tumor microenvironment by innate T cells.

The immunosuppressive tumor microenvironment (TME) remains one of the most prevailing barriers obstructing the implementation of effective immunotherapy against solid-state cancers. Eminently composed of immunosuppressive tumor associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) among others, the TME attenuates the effects of immune checkpoint blockade and adoptive cell therapies, mandating a novel therapy capable of TME remediation. In this review we explore the potential of three innate-like T cell subsets, invariant natural killer T (iNKT), mucosal-associated invariant T (MAIT) cells, and gamma delta T (γδT) cells, that display an intrinsic anti-TAM/MDSC capacity. Exhibiting both innate and adaptive properties, innate-like T cell types express a subset-specific TCR with distinct recombination, morphology, and target cell recognition, further supplemented by a variety of NK activating receptors. Both NK activating receptor and TCR activation result in effector cell cytotoxicity against targeted immunosuppressive cells for TME remediation. In addition, innate-like T cells showcase moderate levels of tumor cell killing, providing dual antitumor and anti-TAM/MDSC function. This latent antitumor capacity can be further bolstered by chimeric antigen receptor (CAR) engineering for recognition of tumor specific antigens to enhance antitumor targeting. In contrast with established CAR-T cell therapies, adoption of these innate-like cell types provides an enhanced safety profile without the risk of graft versus host disease (GvHD), due to their non-recognition of mismatched major histocompatibility complex (MHC) molecules, for use as widely accessible, allogeneic “off-the-shelf” cancer immunotherapy.

A novel immune cell signature for predicting osteosarcoma prognosis and guiding therapy.

Dysregulation of immune cell infiltration in the tumor microenvironment contributes to the progression of osteosarcoma (OS). In the present study, we explored genes related to immune cell infiltration and constructed a risk model to predict the prognosis of and guide therapeutic strategies for OS. The gene expression profile of OS was obtained from TARGET and Gene Expression Omnibus, which were set as the discovery and verification cohorts. CIBERSORT and Kaplan survival analyses were used to analyze the effects of immune cells on the overall survival rates of OS in the discovery cohort. Differentially expressed gene (DEG) analysis and protein–protein interaction (PPI) networks were used to analyze genes associated with immune cell infiltration. Cox regression analysis was used to select key genes to construct a risk model that classified OS tissues into high- and low-risk groups. The prognostic value of the risk model for survival and metastasis was analyzed by Kaplan–Meier survival analyses, receiver operating characteristic curves, and immunohistochemical experiments. Immunological characteristics and response effects of immune checkpoint blockade (ICB) therapy in OS tissues were analyzed using the ESTIMATE and Tumor Immune Dysfunction and Exclusion algorithms, while sensitivity for both targeted and chemotherapy drugs was analyzed using the OncoPredict algorithm. It was demonstrated that the high infiltration of resting dendritic cells in OS tissues was associated with poor prognosis. A total of 225 DEGs were found between the high- and low-infiltration groups of OS tissues, while 94 genes interacted with others. Through COX analyses, among these 94 genes, four genes (including AOC3, CDK6, COL22A1, and RNASE6) were used to construct a risk model. This risk model showed a remarkable prognostic value for survival rates and metastasis in both the discovery and verification cohorts. Even though a high microsatellite instability score was observed in the high-risk group, the ICB response in the high-risk group was poor. Furthermore, using OncoPredict, we found that the high-risk group OS tissues were resistant to seven drugs and sensitive to 25 drugs. Therefore, our study indicates that the resting dendritic cell signature constructed by AOC3, CDK6, COL22A1, and RNASE6 may contribute to predicting osteosarcoma prognosis and thus therapy guidance.

Aerobic glycolysis promotes tumor immune evasion by hexokinase2-mediated phosphorylation of IκBα

High expression of PD-L1 in tumor cells contributes to tumor immune evasion. However, whether PD-L1 expression in tumor cells is regulated by the availability of nutrients is unknown. Here, we show that in human glioblastoma cells, high glucose promotes hexokinase (HK) 2 dissociation from mitochondria and its subsequent binding and phosphorylation of IκBα at T291. This leads to increased interaction between IκBα and μ-calpain protease and subsequent μ-calpain-mediated IκBα degradation and NF-κB activation-dependent transcriptional upregulation of PD-L1 expression. Expression of IκBα T291A in glioblastoma cells blocked high glucose-induced PD-L1 expression and promoted CD8+ Tcell activation and infiltration into the tumor tissue, reducing brain tumor growth. Combined treatment with an HK inhibitor and an anti-PD-1 antibody eliminates tumor immune evasion and remarkably enhances the anti-tumor effect of immune checkpoint blockade. These findings elucidate a novel mechanism underlying the upregulation of PD-L1 expression mediated by aerobic glycolysis and underscore the roles of HK2 as a glucose sensor and a protein kinase in regulation of tumor immune evasion.

Immune phenotypes and checkpoint molecule expression of clonally expanded lymph node-infiltrating T cells in classical Hodgkin lymphoma

Lymph node-infiltrating T cells have been of particular interest in classical Hodgkin lymphoma (cHL). High rates of complete therapeutic responses to antibody-mediated immune checkpoint blockade, even in relapsed/refractory patients, suggest the existence of a T cell-dominated, antigen-experienced, functionally inhibited and lymphoma-directed immune microenvironment. We asked whether clonally expanded T cells (1) were detectable in cHL lymph nodes, (2) showed characteristic immune phenotypes, and (3) were inhibited by immune checkpoint molecule expression. We applied high-dimensional FACS index sorting and single cell T cell receptor αβ sequencing to lymph node-infiltrating T cells from 10 treatment-naïve patients. T cells were predominantly CD4+ and showed memory differentiation. Expression of classical immune checkpoint molecules (CTLA-4, PD-1, TIM-3) was generally low (< 12.0% of T cells) and not different between CD4+ and CD8+ T cells. Degrees of clonal T cell expansion varied between patients (range: 1–18 expanded clones per patient) and was almost exclusively restricted to CD8+ T cells. Clonally expanded T cells showed non-naïve phenotypes and low checkpoint molecule expression similar to non-expanded T cells. Our data suggest that the therapeutic effects of immune checkpoint blockade require mechanisms in addition to dis-inhibition of pre-existing lymphoma-directed T cell responses. Future studies on immune checkpoint blockade-associated effects will identify molecular T cell targets, address dynamic aspects of cell compositions over time, and extend their focus beyond lymph node-infiltrating T cells.

Abstract 5503: Tumor-resilient T-cell signatures identify cellular therapy response biomarkers and reveal FIBP inhibition as an immunotherapy potentiator

Abstract Despite breakthroughs in cancer immunotherapy, most tumor-reactive T cells cannot persist in solid tumors due to an immunosuppressive environment. We developed Tres (Tumor-resilient T cell), a computational model and web server that utilizes single-cell transcriptomic data to identify signatures of T cells that are resilient to immunosuppressive signals, such as TGFβ, TRAIL, and PGE2. Analyzing transcriptomic data from pretreatment or pre-manufacture patient samples, Tres reliably predicts the clinical effectiveness of immune checkpoint blockade or adoptive cell transfer in melanoma, lung, and B-cell malignancies. Further, Tres identified FIBP as the top negative marker of tumor-resilient T cells across many cancers. FIBP knockouts in murine and human CD8 T cells significantly enhanced T-cell mediated cancer-killing and adoptive cell therapy by limiting cholesterol metabolism, which otherwise inhibits effector T-cell function. These results demonstrate Tres’s utility in identifying clinical biomarkers of T-cell effectiveness and potential therapeutic targets for enhancing immunotherapies in solid tumors. Citation Format: Peng Jiang, Yu Zhang. Tumor-resilient T-cell signatures identify cellular therapy response biomarkers and reveal FIBP inhibition as an immunotherapy potentiator [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5503.

Abstract CT009: Phase II trial of perioperative pembrolizumab plus capecitabine and oxaliplatin followed by adjuvant pembrolizumab for resectable gastric and gastroesophageal junction (GC/GEJ) adenocarcinoma

Abstract Background: Perioperative therapy for locally advanced (LA) GC/GEJ adenocarcinoma is standard of care. Although immune checkpoint blockade (ICB) following chemoradiotherapy and resection significantly improves disease free survival (DFS) for esophageal cancer, the effectiveness of ICB together with chemotherapy in LA GC/GEJ cancer is unknown. Methods: This is a multicenter, single-arm, phase II clinical trial of pembrolizumab 200 mg every 3 weeks with capecitabine 625 mg/m2 twice daily and oxaliplatin 130 mg/m2 every 3 weeks (CAPOX) in patients with resectable GC/GEJ adenocarcinoma. Subjects with ECOG PS of 0-1 received CAPOX with pembrolizumab for 3 cycles prior to and 3 cycles following surgery with an additional cycle of pembrolizumab just prior to surgery and 12 months of maintenance pembrolizumab following adjuvant chemoimmunotherapy. The primary endpoint was pathologic complete response (pCR) rate. The study had 80% power to detect an increase in pCR rate from 3% to 15% with a one-sided alpha of 0.05. Secondary endpoints included overall response rate, DFS, and overall survival (OS). This study was registered with ClinicalTrials.gov (NCT02918162). Results: Between 02/10/2017 and 06/17/2021, 36 patients were enrolled with 34 (21 gastric and 13 GEJ) evaluable for efficacy. The median age was 65 years and 17 (50%) patients had an ECOG PS of 1. In total, 29 (85%) patients underwent resection. Seven patients achieved a pCR (20.6% of evaluable patients and 24.1% of those who underwent resection). An additional 6 (17.6%) patients achieved a near CR and 8 (23.5%) demonstrated a significant treatment effect on pathologic review. One patient was deemed unfit for surgery, 2 expired prior to surgery, and 2 were found to have metastatic disease during surgery. At the time of data cut-off, the median follow-up was 19 mo. Of those who underwent resection, 4 (13.7%) experienced disease recurrence and 5 (17.2%) expired. The probability of survival at 1 and 2 years was 0.91 (0.82-1.0) and 0.80 (0.64-0.99), respectively. The median DFS and OS have not been reached. Of the 35 patients who received treatment, treatment related adverse events (AEs) of grade greater than or equal to 3 were reported in 18 (51%) patients. Grade greater than or equal to 3 immune-related AEs were reported in 10 (29%) patients. Three grade 5 AEs occurred, two possibly treatment-related (gastric hemorrhage and gastric perforation) and one unrelated to treatment (cardiac arrest). Conclusion: In LA GC/GEJ adenocarcinoma, the combination CAPOX and pembrolizumab resulted in a pCR rate of 20.6%. The combination was well tolerated and 85.3% of patients underwent surgical resection. This trial met its primary endpoint supporting further investigation of this regimen as an alternative for patients who are unlikely to tolerate triple combination chemotherapy. Correlative studies are in progress. Citation Format: Alexander Grenander Raufi, Shing Lee, Michael May, Armando Del Portillo, Naomi Sender, Sarah Sta Ana, Katarzyna Gautier, Emily Alouani, Haeseong Park, Paul Oberstein, Manish Shah, Gulam A. Manji. Phase II trial of perioperative pembrolizumab plus capecitabine and oxaliplatin followed by adjuvant pembrolizumab for resectable gastric and gastroesophageal junction (GC/GEJ) adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT009.

Abstract 2073: Childhood vaccine-specific CD4+T cell recall coordinates antitumor type I and II immunity

Abstract A recombinant poliovirus (rPV) derived from the live-attenuated Sabin oral polio vaccine strain, is being tested in multi-institutional phase II clinical trials for recurrent glioblastoma (NCT04479241); unresectable, anti-PD-1 refractory melanoma (NCT04577807); and bladder cancer and head and neck squamous cell carcinomas (NCT04690699) in combination with PD-1/PD-L1 blockade. rPV capsid is identical to that of childhood polio vaccines, against which public health mandated vaccination is near universal. In non-vaccinated mice, rPV mediates antitumor efficacy in a replication-dependent manner via engaging innate inflammation and antitumor T cells. Accordingly, it was anticipated that pre-existing immunity to rPV impedes antitumor therapy. Strikingly, despite curtailing intratumor viral replication, prior polio vaccination in mice substantially bolstered the antitumor efficacy of rPV relative to mice vaccinated with a control antigen (KLH). Intratumor recall responses induced by polio and tetanus antigens also delayed tumor growth. Recall antigen therapy was associated with marked intratumor influx of eosinophils, PD1 and Granzyme B expressing type 2 innate lymphoid cells (ILC2s), conventional CD4+ T cells, and increased expression of IFN-γ, TNF, and Granzyme B in tumor infiltrating T cells. The antitumor efficacy of polio recall antigen was mediated by CD4+ T cells, partially depended upon both CD8+ T cells and eosinophils, and was independent of B cells. Intratumor polio and tetanus recall antigen therapy bolstered the antitumor function of tumor-specific OT-I CD8+ T cells, indicating that intratumor CD4+ T cell recall provides help to antitumor CD8+ T cells. Recall antigen therapy complemented antitumor effects of immune checkpoint blockade and innate stimulating immunotherapy. This work reveals that childhood vaccine-specific CD4+ T cells hold cancer immunotherapy potential and represent a novel mechanism to simultaneously engage both type I and II antitumor immunity. Citation Format: Michael Clavon Brown, Zachary P. Mckay, Yuanfan Yang, Darell D. Bigner, Smita K. Nair, Matthias Gromeier. Childhood vaccine-specific CD4+T cell recall coordinates antitumor type I and II immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2073.

Abstract 1326: Loss of p53 sensitizes tumor cells to immune checkpoint blockade therapy via upregulation of IL-33

Abstract Recent studies suggest p53 contributes to poor survival in the context of immune checkpoint blockade (ICB). Mutations to p53 significantly improve the response rate to PD-1 ICB in lung cancer patients. Tumor-derived IL-33 is required for the anti-tumor immune response and efficacy of ICB. However, the relationship between p53 and IL-33 during ICB is unknown. In this study, we characterize the role of the p53/IL-33 axis in regulating the response of the tumor microenvironment to ICB. We use CRISPR-Cas9 to delete Trp53 from murine MC38 colon adenocarcinoma. Deletion of Trp53 and PD-1 ICB synergistically inhibits tumor growth. Il33 is upregulated in the Trp53-deficient and treated tumor cells, and its expression increases with time and response to treatment. Cd4+ and Cd8+ T cell infiltration increases adjacent to IL-33 expressing tumor cells, while Treg infiltration is decreased. Simultaneous deletion of Il33 in MC38 tumors reverses the efficacy PD-1 ICB. Trp53-deficient MC38 in ST2-/- (IL-33 receptor) mice also show no response to PD-1 ICB. Our findings depict a novel mechanism by which the loss of p53 in tumors treated with ICB unleashes the expression of tumoral IL-33 and induces downstream signaling. p53 mutations may be a double-edged sword for cancer, i.e. the loss of the tumor suppressor initially facilitates tumorigenesis, but eventual buildup of mutations and activation of damage pathways, such as NF-kB, leads to upregulation of danger signals in the tumor. These danger signals, such as IL-33, mediate the anti-tumor effect of ICB. Citation Format: David Shihong Gao, Yang Li, Jason Shoush, Runzi Sun, Binfeng Lu. Loss of p53 sensitizes tumor cells to immune checkpoint blockade therapy via upregulation of IL-33 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1326.

TIL classified to memory state are correlated with response to immune checkpoint blockade

Tumor reactivity mediated by tumor infiltrating lymphocytes (TILs) is one of the hallmarks of the clinical effect of immune checkpoint blockade (ICB). Jaiswal et al. used a functional genomics approach to better characterize TIL phenotypes predictive for response to ICB.1

A bioinformatics-based immune-related prognostic index for lung adenocarcinoma that predicts patient response to immunotherapy and common treatments

BackgroundThere is increasing evidence of the effectiveness of immune checkpoint blockade (ICB) therapy for the treatment of lung adenocarcinoma (LUAD). However, the benefits of ICB therapy vary among LUAD patients. Due to the research dimension, existing biomarkers, such as programmed death-ligand 1 (PD-L1) expression and tumor mutation burden (TMB), could not reflect the complex tumor environment, and had low prediction accuracy of ICB. Therefore, we aimed to uncover a prognostic biomarker that could also predict whether a patient would benefit from ICB therapy and other common treatments from multiple dimensions, so as to improve the prediction accuracy of pre-treatment patients.MethodsBased on the LUAD dataset retrieved from The Cancer Genome Atlas (TCGA) database, 50 immune-related hub genes were identified using weighted gene co-expression network analysis and univariate Cox regression analyses. An immune-related gene prognostic index (IRGPI) was constructed using a Cox proportional-hazards model based on 15 genes and validated using GSE72094 dataset. We tested its prognostic accuracy by Kaplan-Meier (K-M) survival curves of the two datasets and assessed its predictive power by comparing area under curve (AUC) of IRGPI with existing biomarkers. Subsequently, we analyzed the molecular and immune characteristics, and evaluated the benefits of ICB by PD-L1 expression and Tumor Immune Dysfunction and Exclusion (TIDE) analysis, predicted the inhibitory concentration 50 of common treatments drugs for two IRGPI score-related subgroups.ResultsPatients in the IRGPI-high subgroup had lower overall survival (OS) than patients in the IRGPI-low subgroup in K-M survival curve in two cohorts. And IRGPI has AUC values of 0.715, 0.724, and 0.743 in 1, 2, and 3 years, respectively. A higher tumor mutation burden and PD-L1 expression and the tumor microenvironment (TME) landscape demonstrated that IRGPI-high subgroup patients may respond better to ICB therapy. Genomics of Drug Sensitivity in Cancer (GDSC) analysis indicated that the IRGPI-high subgroup showed greater sensitivity to chemotherapy.ConclusionsIRGPI is a prospective biomarker for evaluating whether a patient will benefit from ICB therapy and other treatments, and distinguishing patients with different molecular and immune characteristics.