scholarly journals Molecular correlates of immune cytolytic subgroups in colorectal cancer by integrated genomics analysis

NAR Cancer ◽  
2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Constantinos Roufas ◽  
Ilias Georgakopoulos-Soares ◽  
Apostolos Zaravinos
Keyword(s):  
Colorectal Cancer ◽  
T Cells ◽  
Cd8 T Cells ◽  
Immune Checkpoint ◽  
Checkpoint Inhibitors ◽  
Cytolytic Activity ◽  
Immune Checkpoints ◽  
Patient Responsiveness ◽  
Immune Related Genes ◽  
Integrated Genomics

Abstract Although immune checkpoint inhibition (ICI) has shown promising results in metastatic dMMR/MSI-H colorectal cancer (CRC), the majority of pMMR/MSS patients do not respond to such therapies. To systematically evaluate the determinants of immune response in CRC, we explored whether patients with diverse levels of immune cytolytic activity (CYT) have different patterns of chromothripsis and kataegis. Analysis of CRC genomic data from the TCGA, indicated an excess of chromothriptic clusters among CYT-low colon adenocarcinomas, affecting known cancer drivers (APC, KRAS, BRAF, TP53 and FBXW7), immune checkpoints (CD274, PDCD1LG2, IDO1/2 and LAG3) and immune-related genes (ENTPD1, PRF1, NKG7, FAS, GZMA/B/H/K and CD73). CYT-high tumors were characterized by hypermutation, enrichment in APOBEC-associated mutations and kataegis events, as well as APOBEC activation. We also assessed differences in the most prevalent mutational signatures (SBS15, SBS20, SBS54 and DBS2) across cytolytic subgroups. Regarding the composition of immune cells in the tumor milieu, we found enrichment of M1 macrophages, CD8+ T cells and Tregs, as well as higher CD8+ T-cells/Tregs ratio among CYT-high tumors. CYT-high patients had higher immunophenoscores, which is predictive of their responsiveness if they were to be treated with anti-PD-1 alone or in combination with anti-CTLA-4 drugs. These results could have implications for patient responsiveness to immune checkpoint inhibitors.

scholarly journals 281 Measuring immune checkpoint inhibitor efficacy using primary patient-derived 3D spheroids

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A305-A305
Author(s):  
Kathryn Appleton ◽  
Katy Lassahn ◽  
Ashley Elrod ◽  
Tessa DesRochers
Keyword(s):  
T Cells ◽  
Cd8 T Cells ◽  
Immune Checkpoint ◽  
Checkpoint Inhibitors ◽  
Clinical Success ◽  
Single Cells ◽  
Granzyme B ◽  
Immune Checkpoints ◽  
Dependent Manner ◽  
Luminex Technology

BackgroundCancerous cells can utilize immune checkpoints to escape T-cell-mediated cytotoxicity. Agents that target PD-1, PD-L1 and CTLA4 are collectively deemed immune checkpoint inhibitors (ICIs), and many have been approved for treatment of non-small cell lung cancer (NSCLC) and melanoma. Unfortunately, many patients do not respond to these therapies and often experience disease progression. Immunohistochemistry assays to predict response to ICIs have been inconsistent in their readouts and often patients with low expression levels respond to ICIs. Understanding the determinants of ICI response in individual patients is critical for improving the clinical success of this drug class. Using patient-derived spheroids from NSCLC and melanoma primary tissue, we developed a multi-plexed assay for detecting ICI efficacy.MethodsNine NSCLC and 11 melanoma primary tumor samples were dissociated to single cells, classified for immune checkpoint expression and cell content by flow cytometry, and seeded for spheroid formation. Spheroids were treated with pembrolizumab, nivolumab, atezolizumab, ipilimumab or durvalumab across a range of concentrations and monitored for cytotoxicity at 24-hours and viability at 72-hours by multiplexing CellTox™ Green Cytotoxicity Assay and CellTiter-Glo® 3D Cell Viability Assay. IFNγ and granzyme B secretion was assessed using Luminex technology. ICI response was evaluated by determining the concentration-response relationship for all three read-outs.ResultsIncreased IFNγ and granzyme B were detected for every ICI in one or more patient samples. ICI-induced IFNγ secretion inversely correlated with PD-1+ immune cells. Durvalumab was significantly more cytotoxic for both NSCLC and melanoma spheroids compared to the other ICIs and significantly reduced spheroid viability with mean spheroid survival decreasing to 19.5% for NSCLC and 58.2% for melanoma. We evaluated if there was an association between durvalumab response and cell composition and found that percent spheroid survival significantly correlated with CD8+ T-cells for both NSCLC (r=-0.7920, p=0.0191) and melanoma (r=-0.6918, p=0.0390). Furthermore, CD8+ T-cells correlated with durvalumab-induced granzyme B secretion for NSCLC (r=-0.7645, p=0.0271) and melanoma (r=-0.7419, p=0.0221).ConclusionsIn this study we show ICI-specific increases in immune-related analytes in a concentration-dependent manner for NSCLC and melanoma patient-derived spheroids. We detected spheroid cytotoxicity following short term ICI treatment which closely mirrored decreased spheroid viability at a later timepoint. Finally, we can decipher response mechanisms as exemplified by durvalumab-induced granzyme B secretion correlating with the presence of CD8+ T-cells which results in reduced spheroid viability for both tested cancer indications.

Immune checkpoint and checkpoint inhibitors in hepatocellular carcinoma

2018 ◽  
Vol 1 (1) ◽  
pp. 28-32
Author(s):  
Piyawat Komolmit
Keyword(s):  
Hepatocellular Carcinoma ◽  
T Cells ◽  
Major Histocompatibility Complex ◽  
T Cell Receptor ◽  
Immune Checkpoint ◽  
Immune Checkpoint Inhibitors ◽  
Checkpoint Inhibitors ◽  
Cell Receptor ◽  
Immune Checkpoints ◽  
Histocompatibility Complex

การรักษามะเร็งด้วยแนวความคิดของการกระตุ้นให้ภูมิต้านทานของร่างกายไปทำลายเซลล์มะเร็งนั้น ปัจจุบันได้รับการพิสูจน์ชัดว่าวิธีการนี้สามารถหยุดยั้งการแพร่กระจายของเซลล์มะเร็ง โดยไม่ก่อให้เกิดภาวะแทรกซ้อนทางปฏิกิริยาภูมิต้านทานต่ออวัยวะส่วนอื่นที่รุนแรง สามารถนำมาใช้ทางคลินิกได้ ยุคของการรักษามะเร็งกำลังเปลี่ยนจากยุคของยาเคมีบำบัดเข้าสู่การรักษาด้วยภูมิต้านทาน หรือ immunotherapy ยากลุ่ม Immune checkpoint inhibitors โดยเฉพาะ PD-1 กับ CTLA-4 inhibitors จะเข้ามามีบทบาทในการรักษามะเร็งตับในระยะเวลาอันใกล้ จำเป็นแพทย์จะต้องมีความรู้ความเข้าใจในพื้นฐานของ immune checkpoints และยาที่ไปยับยั้งโมเลกุลเหล่านี้ Figure 1 เมื่อ T cells รับรู้แอนทิเจนผ่านทาง TCR/MHC จะมีปฏิกิริยาระหว่าง co-receptors หรือ immune checkpoints กับ ligands บน APCs หรือ เซลล์มะเร็ง ทั้งแบบกระตุ้น (co-stimulation) หรือยับยั้ง (co-inhibition) TCR = T cell receptor, MHC = major histocompatibility complex

scholarly journals Inhibition of the PI3K/mTOR Pathway in Breast Cancer to Enhance Response to Immune Checkpoint Inhibitors in Breast Cancer

2021 ◽  
Vol 22 (10) ◽  
pp. 5207
Author(s):  
Chi Yan ◽  
Jinming Yang ◽  
Nabil Saleh ◽  
Sheau-Chiann Chen ◽  
Gregory D. Ayers ◽  
...  
Keyword(s):  
Breast Cancer ◽  
T Cells ◽  
Tumor Growth ◽  
Cd8 T Cells ◽  
Immune Checkpoint ◽  
Immune Checkpoint Inhibitors ◽  
Checkpoint Inhibitors ◽  
Mtor Pathway ◽  
Complete Regression ◽  
Mtor Inhibition

Objectives: Inhibition of the PI3K/mTOR pathway suppresses breast cancer (BC) growth, enhances anti-tumor immune responses, and works synergistically with immune checkpoint inhibitors (ICI). The objective here was to identify a subclass of PI3K inhibitors that, when combined with paclitaxel, is effective in enhancing response to ICI. Methods: C57BL/6 mice were orthotopically implanted with syngeneic luminal/triple-negative-like PyMT cells exhibiting high endogenous PI3K activity. Tumor growth in response to treatment with anti-PD-1 + anti-CTLA-4 (ICI), paclitaxel (PTX), and either the PI3Kα-specific inhibitor alpelisib, the pan-PI3K inhibitor copanlisib, or the broad spectrum PI3K/mTOR inhibitor gedatolisib was evaluated in reference to monotherapy or combinations of these therapies. Effects of these therapeutics on intratumoral immune populations were determined by multicolor FACS. Results: Treatment with alpelisib + PTX inhibited PyMT tumor growth and increased tumor-infiltrating granulocytes but did not significantly affect the number of tumor-infiltrating CD8+ T cells and did not synergize with ICI. Copanlisib + PTX + ICI significantly inhibited PyMT growth and increased activation of intratumoral CD8+ T cells as compared to ICI alone, yet did not inhibit tumor growth more than ICI alone. In contrast, gedatolisib + ICI resulted in significantly greater inhibition of tumor growth compared to ICI alone and induced durable dendritic-cell, CD8+ T-cell, and NK-cell responses. Adding PTX to this regimen yielded complete regression in 60% of tumors. Conclusion: PI3K/mTOR inhibition plus PTX heightens response to ICI and may provide a viable therapeutic approach for treatment of metastatic BC.

scholarly journals Tumor and Peripheral Immune Status in Soft Tissue Sarcoma: Implications for Immunotherapy

Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3885
Author(s):  
Luana Madalena Sousa ◽  
Jani Sofia Almeida ◽  
Tânia Fortes-Andrade ◽  
Manuel Santos-Rosa ◽  
Paulo Freitas-Tavares ◽  
...  
Keyword(s):  
T Cells ◽  
Soft Tissue ◽  
Cd8 T Cells ◽  
Soft Tissue Sarcomas ◽  
Suppressor Cells ◽  
Response To Therapy ◽  
Immune Checkpoints ◽  
Soluble Factors ◽  
Lymphocyte To Monocyte Ratio ◽  
Immune Related Genes

Soft Tissue Sarcomas (STS) are a heterogeneous and rare group of tumors. Immune cells, soluble factors, and immune checkpoints are key elements of the complex tumor microenvironment. Monitoring these elements could be used to predict the outcome of the disease, the response to therapy, and lead to the development of new immunotherapeutic approaches. Tumor-infiltrating B cells, Natural Killer (NK) cells, tumor-associated neutrophils (TANs), and dendritic cells (DCs) were associated with a better outcome. On the contrary, tumor-associated macrophages (TAMs) were correlated with a poor outcome. The evaluation of peripheral blood immunological status in STS could also be important and is still underexplored. The increased lymphocyte-to-monocyte ratio (LMR) and neutrophil-to-lymphocyte ratio (NLR), higher levels of monocytic myeloid-derived suppressor cells (M-MDSCs), and Tim-3 positive CD8 T cells appear to be negative prognostic markers. Meanwhile, NKG2D-positive CD8 T cells were correlated with a better outcome. Some soluble factors, such as cytokines, chemokines, growth factors, and immune checkpoints were associated with the prognosis. Similarly, the expression of immune-related genes in STS was also reviewed. Despite these efforts, only very little is known, and much research is still needed to clarify the role of the immune system in STS.

scholarly journals 540 Baseline mTOR transcriptional signatures in CD8 T cells are associated with immune-related adverse events but not anti-tumor responses in patients receiving immune checkpoint inhibitors

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A570-A570
Author(s):  
Chen Zhao ◽  
Matthew Mule ◽  
Andrew Martins ◽  
Iago Pinal Fernandez ◽  
Renee Donahue ◽  
...  
Keyword(s):  
T Cells ◽  
Adverse Events ◽  
Tumor Immunity ◽  
Cd8 T Cells ◽  
Immune Checkpoint ◽  
Immune Checkpoint Inhibitors ◽  
Checkpoint Inhibitors ◽  
Effector Memory ◽  
Link Type ◽  
Anti Tumor Activity

BackgroundImmune checkpoint inhibitors (ICIs) have changed the cancer treatment landscape, but immune-related adverse events (irAEs) can affect a wide range of tissues in patients receiving ICIs. Severe irAEs can be life-threatening or fatal and prohibit patients from receiving further ICI treatment. While the clinical features of irAEs are well documented, the pathological mechanisms and predictive biomarkers are largely unknown. In addition, there is a critical need to preserve ICI-induced anti-tumor immunity while controlling for irAEs, which requires deciphering molecular and cellular signatures associated specifically with irAEs beyond those more generally linked to anti-tumor immunity.MethodsTo unbiasedly identify immune cells and states associated with irAEs, we applied CITE-seq to measure transcripts and surface proteins (83 protein markers) from PBMCs collected from patients with thymic epithelial tumors before and after treatment with an anti-PD-L1 antibody (avelumab, NCT01772004, NCT03076554).ResultsSamples from 9 patients were analyzed. No patient had a history of pre-existing paraneoplastic autoimmune disease. Anti-tumor activity was observed in all cases, and 5 patients had clinical and/or biochemical evidence of immune-related muscle inflammation (myositis with or without myocarditis). Multilevel models applied within highly resolved cell clusters revealed transcriptional states associated with ICI response and more uniquely with irAEs. A total of 190,000 cells were included in the analysis after quality control. Most notably, CD45RA+ effector memory CD8 T cells with an mTOR transcriptional signature were highly enriched at baseline and post treatment in patients with irAEs.ConclusionsOur findings suggest the potential therapeutic avenues by using mTOR inhibitors to dampen autoimmune responses while potentially sparing anti-tumor activity, to prevent treatment discontinuation and improve clinical outcomes for cancer patients treated with ICIs.AcknowledgementsThis research was supported in part by the Intramural Research Program of the NCI (the Center for Cancer Research), NIAID and NIAMS, and through a Cooperative Research and Development Agreement between the National Cancer Institute and EMD Serono.Trial RegistrationNCT01772004, NCT03076554Ethics ApprovalThis study is approved by NCI institutional review board.

scholarly journals 754 TIGIT-PVR is a key immune checkpoint and therapeutic target in HPV-positive head and neck squamous cell carcinomas

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A788-A788
Author(s):  
Xiuning Le ◽  
Minghao Dang ◽  
Venkatesh Hegde ◽  
Bo Jiang ◽  
Ravaen Slay ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Murine Model ◽  
Immune Checkpoint ◽  
Therapeutic Target ◽  
Therapeutic Efficacy ◽  
Cd8 T Cell ◽  
Immune Checkpoints ◽  
Rna Seq

BackgroundHuman papillomavirus (HPV)-positive head and neck squamous cell carcinoma (HPV+ HNSCC) is a disease that has moderate response to anti-PD-1/L1 immune checkpoint blockade, with the response rates less than 20% and median progression-free survival less than 3 months. A greater understanding of tumor intrinsic and extrinsic factors that restrict anti-tumor immunity in the tumor immune microenvironment (TIME) is needed to identify other immune checkpoints to enhance therapeutic efficacy.MethodsTwo cohorts (TCGA n=72 and a separate cohort n=84) of surgically resected, treatment-naïve HPV+ HNSCC with RNA-seq were analyzed to understand the immune features. In addition, single-cell RNA-seq and TCR-seq were performed on 18 cases to further delineate the immune molecules' interactions. An immune-competent murine HPV+ HNSCC model was used to preliminarily evaluate the therapeutic efficacy.ResultsIn two bulk-sequenced HPV+ HNSCC cohorts, TIGIT ligands PVR and NECTIN2 were found to associate with an epithelial-to-mesenchymal gene expression signature, suppression of IFNα and IFNγ signaling, a stromal-enriched or immune-excluded TIME, and poor survival. Single-cell RNA-seq of over 72,000 cells of HPV+ HNSCC revealed that the PVR/NECTIN ligand TIGIT was highly prevalent in T-cells (34%), significantly higher than PD1- (20%, p<0.01). There is an enrichment of cell-cell interactions mediated by TIGIT-PVR/NECTIN2 in the TIME of HPV+HNSCC versus normal tonsil. TIGIT was the most differentially upregulated immune checkpoint on clonally expanded CD8+T-cells and was abundant on antigen-experienced, tissue-resident memory CD8+T-cell and T-regulatory subsets. TIGIT ligands PVR, NECTIN1, and NECTIN2 were abundant on mature regulatory dendritic cells (DCs), immunosuppressive plasmacytoid (p)DCs, and macrophages, respectively. TIGIT and PD-1 co-blockade in the mEER syngeneic murine model significantly reduced tumor growth, improved survival, restored effector function of HPV16E7-specific CD8+T cells, natural killer cells, and DCs, and conferred tumor re-challenge protection.ConclusionsTIGIT-PVR/NECTIN receptors/ligands are more abundant than PD-1/L1 in the TIME of HPV+ HNSCC. Co-blockade of TIGIT and PD-1 immune checkpoints enhanced anti-tumor efficacy in a CD8+ T-cell-dependent manner and conferred long-term immune protection in a murine model. Our study nominates TIGIT as a therapeutic target for HPV+ HNSCC.

Association of KMT2C/D loss-of-function mutations with tumor infiltrating lymphocytes and response to immune checkpoint inhibitors in solid tumors.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 2587-2587
Author(s):  
Ruiqi Liu ◽  
Yanling Niu ◽  
Xin Zhang ◽  
Tonghui Ma
Keyword(s):  
Gene Expression ◽  
Colorectal Cancer ◽  
T Cells ◽  
Immune Checkpoint Inhibitors ◽  
Checkpoint Inhibitors ◽  
Tumor Infiltrating Lymphocytes ◽  
Loss Of Function ◽  
Cancer Types ◽  
Immune Related Genes ◽  
Infiltrating Lymphocytes

2587 Background: Dysregulation of HMTs plays an important role in tumorigenesis. KMT2C and KMT2D are enzymatically active scaffold proteins that form the core of mammalian COMPASS complexes, which methylate the histone 3 lysine 4. Both KMT2C and KMT2D are involved in the regulation of gene expression. Therefore, we explored the associations of KMT2C/D loss-of-function (LOF) mutations with the expression of immune-related genes, the levels of tumor infiltrating lymphocytes (TILs), and response to immune checkpoint inhibitors (ICIs). Methods: KMT2C/D LOF mutations were defined as nonsense, frameshift, splice site variants within consensus regions, start lost, and stop lost/gained variants. An ICIs treatment cohort from the MSKCC was used for exploring the associations between KMT2C/D LOF mutations and ICIs efficacy. The RNA-Seq data obtained from the TCGA cohort was used for analysis of gene expression and the levels of TILs using CIBERSORT. Results: In MSKCC pan-cancer dataset, patients with KMT2C/D LOF mutations had a relatively longer median overall survival (OS) compared to those with non-LOF mutations, although the result did not reach statistical significance (P = 0.0832). Then we analyzed the predictive roles of KMT2C/D LOF mutations for each cancer type. The results showed that the predictive role of KMT2C/D LOF mutations for the clinical efficacy of ICIs therapy was only observed in colorectal cancer (P = 0.045). However, we did not find the associations of KMT2C/D LOF mutations with ICIs efficacy in bladder cancer, breast cancer, melanoma, glioma, head and neck cancer, renal cell carcinoma, NSCLC, and esophagogastric cancer. Consistently, analysis of TILs in colorectal cancer revealed that KMT2C/D LOF was associated with increased infiltration of several types of immune cells, such as CD8+ T cells (P = 0.0001), activated NK cells (P = 0.0001), M1 macrophage (P = 0.0005), M2 macrophage (P = 0.0115), and neutrophils (P = 0.0209). Meanwhile, regulatory T cells (Tregs) (P = 0.0048) and M0 macrophage (P = 0.0043) were dramatically decreased in KMT2C/D LOF group for colorectal cancer. Moreover, there were no significant relationships between KMT2C/D LOF and the levels of TILs in other cancer types. Our data also demonstrated that KMT2C and KMT2D could regulate the expression of more than 30 immune-related genes in colorectal cancer. Conclusions: Our data indicated that KMT2C/D LOF mutations were significantly correlated with better outcomes of ICIs therapy in colorectal cancer, suggesting it can be as a useful predictor for response to ICIs in colorectal cancer. Meanwhile, we found the associations of KMT2C/D LOF with the levels of TILs in colorectal cancer, but not in other cancer types, indicating that the efficacy of ICIs was consistent with the levels of TILs.

scholarly journals A Systematic Review of the Tumor-Infiltrating CD8+ T-Cells/PD-L1 Axis in High-Grade Glial Tumors: Toward Personalized Immuno-Oncology

2021 ◽  
Vol 12 ◽  
Author(s):  
Mahdi Abdoli Shadbad ◽  
Zahra Asadzadeh ◽  
Negar Hosseinkhani ◽  
Afshin Derakhshani ◽  
Nazila Alizadeh ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Checkpoint ◽  
Response Rate ◽  
Checkpoint Inhibitors ◽  
Immune Checkpoints ◽  
Cancer Therapies ◽  
High Grade ◽  
Glial Tumors ◽  
Anti Cancer ◽  
The Impact

Based on preclinical findings, programmed death-ligand 1 (PD-L1) can substantially attenuate CD8+ T-cell-mediated anti-tumoral immune responses. However, clinical studies have reported controversial results regarding the significance of the tumor-infiltrating CD8+ T-cells/PD-L1 axis on the clinical picture and the response rate of patients with high-grade glial tumors to anti-cancer therapies. Herein, we conducted a systematic review according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statements to clarify the clinical significance of the tumor-infiltrating CD8+ T-cells/PD-L1 axis and elucidate the impact of this axis on the response rate of affected patients to anti-cancer therapies. Indeed, a better understanding of the impact of this axis on the response rate of affected patients to anti-cancer therapies can provide valuable insights to address the futile response rate of immune checkpoint inhibitors in patients with high-grade glial tumors. For this purpose, we systematically searched Scopus, Web of Science, Embase, and PubMed to obtain peer-reviewed studies published before 1 January 2021. We have observed that PD-L1 overexpression can be associated with the inferior prognosis of glioblastoma patients who have not been exposed to chemo-radiotherapy. Besides, exposure to anti-cancer therapies, e.g., chemo-radiotherapy, can up-regulate inhibitory immune checkpoint molecules in tumor-infiltrating CD8+ T-cells. Therefore, unlike unexposed patients, increased tumor-infiltrating CD8+ T-cells in anti-cancer therapy-exposed tumoral tissues can be associated with the inferior prognosis of affected patients. Because various inhibitory immune checkpoints can regulate anti-tumoral immune responses, the single-cell sequencing of the cells residing in the tumor microenvironment can provide valuable insights into the expression patterns of inhibitory immune checkpoints in the tumor micromovement. Thus, administrating immune checkpoint inhibitors based on the data from the single-cell sequencing of these cells can increase patients’ response rates, decrease the risk of immune-related adverse events development, prevent immune-resistance development, and reduce the risk of tumor recurrence.

IMMU-52. EFFECTS OF IMMUNE CHECKPOINT BLOCKADE ON ANTIGEN-SPECIFIC CD8+ T CELLS FOR USE IN ADOPTIVE CELLULAR THERAPY

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi104-vi104
Author(s):  
Elizabeth Ogando-Rivas ◽  
Paul Castillo ◽  
Noah Jones ◽  
Vrunda Trivedi ◽  
Jeffrey Drake ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cellular Therapy ◽  
Checkpoint Inhibitors ◽  
Cell Subset ◽  
Checkpoint Blockade ◽  
Immune Checkpoints ◽  
Effector Memory ◽  
Dependent Manner

Abstract BACKGROUND Adoptive T-cell therapies have been successfully used as treatment for patients diagnosed with advanced cancers. Unfortunately, for some refractory cancers, they have failed. To overcome this, checkpoint inhibitors have shown to rescue immune anti-tumor responses. We hypothesized that in-vitro checkpoint blockade during T-cell stimulation and expansion with RNA-pulsed dendritic cells may enhance the activity of antigen-specific T-cells and improve the efficacy of ACT platforms. METHODS Human PBMCs were isolated from CMV seropositive donors to generate DCs and pulsed them with CMVpp65-mRNA to educate T-cells in co-culture for 15-days. We targeted pp65 antigen which is ubiquitously expressed by glioblastoma cells. Three checkpoint blockade conditions were evaluated (anti-PD1, anti-Tim3 and anti-PD1+Tim3). IL2 was added every 3 days as well as the blockade antibodies. Immunephenotyping was performed on Day-0 and Day-15. Polyfunctional antigen specific responses were evaluated upon rechallenge with CMVpp65 peptides. RESULTS CMVpp65 activated CD8+ T-cells upregulate Lag3 and Tim3 (p= &lt; 0.0001). Tim3 blockade alone or in combination led to a significant upregulation of Lag3 expression on CD8+pp65Tetramer+ central memory, effector memory, and TEMRA T-cells. This latter T-cell subset uniquely maintain double-positive Tim3/Lag3 expression after blockade. In contrast, PD-1 blockade had minimal effects on Tim3 or Lag3 expression. In addition, IFN-g secretion was reduced in T-cells treated with Tim3 blockade in a dose-dependent manner (p= 0.004). CONCLUSION In this study, we have identified a potential activating component of Tim3 and linkage between Tim3 and Lag3 signaling upon blocking Tim3 axis during T-cell antigen presenting cell interactions that should be considered when targeting immune checkpoints for clinical use.

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