scholarly journals 1-Methylnicotinamide is an immune regulatory metabolite in human ovarian cancer

2020 ◽  
Author(s):  
Marisa K. Kilgour ◽  
Sarah MacPherson ◽  
Lauren Zacharias ◽  
Sarah Keyes ◽  
Brenna Pauly ◽  
...  

ABSTRACTImmune regulatory metabolites are key features of the tumor microenvironment (TME), yet with a few notable exceptions, their identities remain largely unknown. We uncovered the immune regulatory metabolic states and metabolomes of sorted tumor and stromal, CD4+, and CD8+ cells from the tumor and ascites of patients with high-grade serous ovarian cancer (HGSC) using high-dimensional flow cytometry and metabolomics supplemented with single cell RNA sequencing. Flow cytometry revealed that tumor cells show a consistently greater uptake of glucose than T cells, but similar mitochondrial activity. Cells within the ascites and tumor had pervasive metabolite differences, with a striking enrichment in 1-methylnicotinamide (MNA) in T cells infiltrating the tumor compared to ascites. Despite the elevated levels of MNA in T cells, the expression of nicotinamide N-methyltransferase, the gene encoding the enzyme that catalyses the transfer of a methyl group from S-adenosylmethionine to nicotinamide, was restricted to fibroblasts and tumor cells. Treatment of T cells with MNA resulted in an increase in T cell-mediated secretion of the tumor promoting cytokine tumor necrosis factor alpha. Thus, the TME-derived metabolite MNA contributes to an alternative and non-cell autonomous mechanism of immune modulation of T cells in HGSC. Collectively, uncovering the tumor-T cell metabolome may reveal metabolic vulnerabilities that can be exploited using T cell-based immunotherapies to treat human cancer.

2021 ◽  
Vol 7 (4) ◽  
pp. eabe1174
Author(s):  
Marisa K. Kilgour ◽  
Sarah MacPherson ◽  
Lauren G. Zacharias ◽  
Abigail E. Ellis ◽  
Ryan D. Sheldon ◽  
...  

Immune regulatory metabolites are key features of the tumor microenvironment (TME), yet with a few exceptions, their identities remain largely unknown. Here, we profiled tumor and T cells from tumor and ascites of patients with high-grade serous carcinoma (HGSC) to uncover the metabolomes of these distinct TME compartments. Cells within the ascites and tumor had pervasive metabolite differences, with a notable enrichment in 1-methylnicotinamide (MNA) in T cells infiltrating the tumor compared with ascites. Despite the elevated levels of MNA in T cells, the expression of nicotinamide N-methyltransferase, the enzyme that catalyzes the transfer of a methyl group from S-adenosylmethionine to nicotinamide, was restricted to fibroblasts and tumor cells. Functionally, MNA induces T cells to secrete the tumor-promoting cytokine tumor necrosis factor alpha. Thus, TME-derived MNA contributes to the immune modulation of T cells and represents a potential immunotherapy target to treat human cancer.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1633-1633
Author(s):  
Marcelo A. Navarrete ◽  
Benjamin Kisser ◽  
Hendrik J. Veelken

Abstract Abstract 1633 Introduction: The individual collection of epitopes within the variable regions of the unique immunoglobulin expressed by every mature B-cell lymphoma (idiotype, or Id) represents a tumor-specific antigen and lends itself as a target for therapeutic vaccination strategies. Immunization with tumor Id has the capacity to elicit polyclonal antibody responses as well as CD8+ and CD4+ T cells recognizing Id-derived peptides presented on class I and class II HLA molecules, respectively. Due to a perceived low immunogenicity of lymphoma-derived Id, most Id vaccines tested in clinical trials so far have been formulated as conjugates with the strongly immunogenic carrier keyhole limpet hemocyanin (KLH). In contrast, we have consistently observed high rates of humoral and cellular anti-Id immune responses in consecutive trials of active immunization with unconjugated recombinant Fab fragments of Id in indolent B-cell lymphomas (Bertinetti et al., Cancer Res. 2006; Navarrete et al., BLOOD 2011). We therefore hypothesized that Id Fab fragment might be intrinsically more immunogenic than entire Id Ig and tested this hypothesis by comparative in vitro experiments. Methods: Monocyte-derived dendritic cells (DC) where loaded with human monoclonal IgG, papain-digested Fab fragments, Fc fragments, or recombinant lymphoma-derived Fab fragments. Functional DC phenotypes were assessed by flow cytometry of crucial maturation and activation markers. IL-10 and IL-12 was measured in DC culture supernatants by ELISA. Antigen-loaded DC where subsequently used for priming of CFSE-labeled autologous peripheral blood mononuclear cells. Stimulated T cell populations were analyzed by multicolor flow cytometry. Results: Loading of DC with Fab, Fc, IgG, or mixtures of Fab and Fc fragments did not alter surface expression of CD11c, CD80, CD83, CD86, HLA-DR, PDL-1 and PDL-2 on DC. Likewise, the various antigens did not influence the cytokine release by DC during the loading or maturation process. DC loaded with isolated Fab fragments induced significantly higher proliferation of both CD4+ and CD8+ T cells than undigested IgG. The mean proliferation rate of CD4+ cells stimulated with Fab fragments was 18.5% versus 5.6% for undigested IgG stimulation (p=0.021); proliferation rates of CD8+ cells were 14.2% versus 6.2% (p=0.034). These results were reproduced for 4 different monoclonal IgGs tested on 4 different donors. The addition of Fc fragments to Fab reduced the proliferation rates of CD4+ and CD8+ cells to 10.2% and 8.6% respectively. In addition, DC loaded with undigested IgG induced a relative increase in the number of CD25high/FoxP3+ regulatory T cells compared with Fab stimulation (8.2% versus 1.4%; p<0.01). Conclusions: Isolated Fab fragments, i.e. the Id portions that contain the individual candidate antigenic epitopes of B-cell lymphomas, prime autologous T cells in vitro more efficiently than entire IgG. This finding is consistent with the high immune response rate against recombinant unconjugated Fab fragments observed in vivo in our clinical vaccination trials. Peptide sequences shared between Ig molecules that are predominantly located in the IgG Fc fragment appear to exert an inhibitory effect on T-cell priming. In accordance with our recent in vivo data in a syngeneic mouse model of Id vaccination (Warncke et al., Cancer Immunol. Immunother. 2011), this effect may be mediated by effective activation of Treg. Fab fragments therefore appear to be the more immunogenic and therefore preferable Ig antigenic format for active anti-Id immunotherapy. Furthermore, the inhibitory effects of IgG Fc offers a potential explanation for the recently reported lack of efficacy of Id vaccination in IgG-expressing follicular lymphomas in a randomized phase III trial, in which patients with IgM-expressing lymphomas, in contrast, had a significant benefit from Id vaccination in intention-to-treat analyses (Schuster et al., JCO 2011). Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4070-4070
Author(s):  
Harbani Malik ◽  
Ben Buelow ◽  
Udaya Rangaswamy ◽  
Aarti Balasubramani ◽  
Andrew Boudreau ◽  
...  

Introduction The restricted expression of CD19 in the B-cell lineage makes it an attractive target for the therapeutic treatment of B-cell malignancies. Many monoclonal antibodies and antibody drug conjugates targeting CD19 have been developed, including bispecific T-cell redirecting antibodies (T-BsAbs). In addition, anti-CD19 chimeric antigen receptor T-cells (CAR-T) have been approved to treat leukemia and lymphoma. However, despite the impressive depth of responses achieved by T-cell redirecting approaches such as T-BsAbs and CAR-T cells, toxicity from over-activation of T-cells remains a substantial limitation for this type of therapy, in particular neurotoxicity. In designing TNB-486, a novel CD19 x CD3 T-BsAb, we endeavored to retain activity against CD19-positive tumor cells while limiting the cytokine secretion thought to underlie toxicity from T-cell redirecting therapies. Utilizing TeneoSeek, a next generation sequencing (NGS)-based discovery pipeline that leverages in silico analysis of heavy chain only/fixed light chain antibody (HCA/Flic, respectively) sequences to enrich for antigen specific antibodies, we made a high affinity αCD19 HCA and a library of αCD3 Flic antibodies that showed a >2 log range of EC50s for T cell activation in vitro. Of note, the library contained a low-activating αCD3 that induced minimal cytokine secretion even at concentrations that mediated saturating T-cell dependent lysis of lymphoma cells (when paired with an αCD19 HCA). We characterized the relative efficacy and potential therapeutic window of this unique molecule, TNB-486, in vitro and in vivo and compared it to two strongly activating bispecific CD19 x CD3 antibodies similar to those currently available and in clinical development. Methods Affinity measurements of the αCD19 moiety were made via Biacore (protein) and flow cytometry (cell surface). Stability measurements were made by subjecting the molecule to thermal stress and the %aggregation was measured by Size Exclusion Chromatography. T-cell activation was measured via flow cytometry (CD69 and CD25 expression) and cytokine was measured by ELISA (IL-2, IL-6, IL-10, INF-ɣ, and TNFα) in vitro. Lysis of B-cell tumor cell lines (Raji, RI-1, and Nalm6) was measured via flow cytometry in vitro. In vivo, NOG mice were engrafted subcutaneously with NALM-6 or SUDHL-10 cells and intravenously with human peripheral blood mononuclear cells (huPBMC), and the mice treated with multiple doses of TNB-486 or negative or positive control antibody. Tumor burden was evaluated via caliper measurement. Pharmacodynamic/Pharmacokinetic (PK/PD) studies were performed in NOG mice. A pharmacokinetic (PK) study was performed in BALB/c mice, and a tolerability and PK study are ongoing in cynomolgus monkeys. Results TNB-486 bound to cell surface CD19 with single digit nanomolar affinity (~3nM). EC50s for cytotoxicity were in the single-digit nanomolar range for TNB-486, and sub-nanomolar for the strongly activating controls; TNB-486 maximum achievable lysis was identical to the positive controls. TNB-486 induced significantly less cytokine release for all cytokines tested compared to the positive controls even at doses saturating for tumor lysis. No off-target activation was observed in the absence of CD19 expressing target cells. In vivo, TNB-486 eradicated all CD19-positive tumors tested (NALM-6 and SUDHL10) at doses as little as 1µg administered every four days after tumors had reached ~200mm3. TNB-486 showed a PK profile consistent with other IgG molecules in mice (T1/2 ~6 days in mice). Conclusions TNB-486 induced comparable lysis of CD19-positive tumor cells as the strongly activating control bispecific antibodies while inducing significantly reduced cytokine secretion, even at doses saturating for tumor lysis in vitro. In vivo TNB-486 eradicated all tested CD19 positive tumor cell lines in established tumor models. No off-target binding was observed. In summary, TNB-486 shows promise as a lymphoma therapeutic differentiated from T-cell targeted therapies currently in the clinic and in clinical trials. Disclosures Malik: Teneobio, Inc.: Employment, Equity Ownership. Buelow:Teneobio, Inc.: Employment, Equity Ownership. Rangaswamy:Teneobio, Inc.: Employment, Equity Ownership. Balasubramani:Teneobio, Inc.: Employment, Equity Ownership. Boudreau:Teneobio, Inc.: Employment, Equity Ownership. Dang:Teneobio, Inc.: Employment, Equity Ownership. Davison:Teneobio, Inc.: Employment, Equity Ownership. Force Aldred:Teneobio, Inc.: Equity Ownership. Iyer:Teneobio, Inc.: Employment, Equity Ownership. Jorgensen:Teneobio, Inc.: Employment, Equity Ownership. Pham:Teneobio, Inc.: Employment, Equity Ownership. Prabhakar:Teneobio, Inc.: Employment, Equity Ownership. Schellenberger:Teneobio, Inc.: Employment, Equity Ownership. Ugamraj:Teneobio, Inc.: Employment, Equity Ownership. Trinklein:Teneobio, Inc.: Employment, Equity Ownership. Van Schooten:Teneobio, Inc.: Employment, Equity Ownership.


2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii362-iii363
Author(s):  
Samuel Rivero-Hinojosa ◽  
Melanie Grant ◽  
Aswini Panigrahi ◽  
Huizhen Zhang ◽  
Veronika Caisova ◽  
...  

Abstract T cell immunotherapies are promising new tools to combat high-risk subgroups of medulloblastoma without increasing the late effects burden. The ideal target antigen of an effective antitumor T-cell response is abundantly expressed by tumor cells but not by normal tissues, in order to limit off-target effects. Tumors translate a host of highly novel transcripts that are the result of aberrations in tumor DNA and the unmasking of alternative or novel exons. We developed a novel proteogenomic approach to identify tumor-restricted peptides and used them to select and expand T cells capable of mounting a tumor-specific cytotoxic immune response. Using RNA-seq and WGS data, we created personalized custom searchable databases containing predicted novel proteins from somatic mutations, novel junctions and fusion transcripts from 56 medulloblastoma tumors. By searching these databases with raw mass spectrometry data from paired medulloblastoma tumors, we identified tens of neoantigen peptides arising from the translation of tumor-specific transcripts; novel isoforms being the predominant source. We tested these peptides for their ability to select and expand autologous polyclonal populations of T cells and tested the immunogenicity of each individual peptide. Flow cytometry revealed populations of CD4+ and CD8+ cells with an activation profile marked by IFN-γ and TNF-α. Immunosuppressive marker profiles were also characterized. Using cytotoxicity assays, we demonstrated that tumor specific T cells can eliminate neoantigen bearing tumor cells. Thus, proteogenomics can identify immunogenic tumor specific peptides that can be used to create a personalized, targeted T cell therapy for children with high risk medulloblastoma.


2021 ◽  
Vol 22 (8) ◽  
pp. 3906
Author(s):  
Alessandra Rossi ◽  
Ilenia Pacella ◽  
Silvia Piconese

T cells undergo activation and differentiation programs along a continuum of states that can be tracked through flow cytometry using a combination of surface and intracellular markers. Such dynamic behavior is the result of transcriptional and post-transcriptional events, initiated and sustained by the activation of specific transcription factors and by epigenetic remodeling. These signaling pathways are tightly integrated with metabolic routes in a bidirectional manner: on the one hand, T cell receptors and costimulatory molecules activate metabolic reprogramming; on the other hand, metabolites modify T cell transcriptional programs and functions. Flow cytometry represents an invaluable tool to analyze the integration of phenotypical, functional, metabolic and transcriptional features, at the single cell level in heterogeneous T cell populations, and from complex microenvironments, with potential clinical application in monitoring the efficacy of cancer immunotherapy. Here, we review the most recent advances in flow cytometry-based analysis of gene expression, in combination with indicators of mitochondrial activity, with the aim of revealing and characterizing major metabolic pathways in T cells.


2020 ◽  
Vol 8 (Suppl 2) ◽  
pp. A47.2-A48
Author(s):  
E Criado-Moronati ◽  
A Gosselink ◽  
J Kollet ◽  
A Dzionek ◽  
B Heemskerk

BackgroundThe adoptive cell transfer (ACT) of tumor-infiltrating T lymphocytes (TILs) has shown remarkable results in patients with different cancer types. The antitumor effect of this therapy is mainly attributed to a small fraction of tumor-reactive T lymphocytes (TRLs) that recognize mutated peptides as well as overexpressed self-antigens. Therefore, the enrichment and expansion of TRLs constitutes a promising immunotherapy approach. However, the specific targeting of individual mutated antigens represents a daunting challenge for widespread therapeutic application. Alternatively, we hypothesize that TRLs could be identified and enriched by a surface marker (or combination thereof) in an antigen-independent manner as a result of the chronic antigen exposure and other factors present in the tumor microenvironment (TME).Materials and MethodsWe screened T cell activation and exhaustion markers, among others, on different tumor tissues using the MACSima™ Imaging Platform, an instrument for the highly multiplexed immunofluorescence imaging technology MICS (Multiparameter Imaging Cell Screen), enabling investigation of hundreds of markers on a single section. Moreover, flow cytometry and single-cell RNA sequencing analyses of T cells from tumor digests were performed to complement the characterization of TILs.ResultsThe MICS results highlighted the complexity of the TME, mainly composed of tumor cells, fibroblasts and endothelial vessels. In some cases, an extensive immune infiltrate consisted of T cells, plasma cells, some B cells and distinct myeloid cells was observed. Particularly, CD8 T cells from different tumor areas exhibited a tissue-resident memory phenotype with the expression of CD69, CD45RO or CD103. Activated/exhausted CD8 T cells were homogenously found across the imaged tumor areas. However, there was a tendency to find them in close proximity to tumor cells, especially for CD8 subsets expressing CD39 and other relevant markers, which may suggest the identification of tumor-reactive CD8 T cell populations. Flow cytometry data revealed the presence of similar T cell phenotypes in the patient´s TILs from tumor digests.ConclusionsThis imaging technology offers the possibility to study multiple parameters—including the localization—of relevant cells in the TME such as T cells. The phenotypic and functional characterization of different T cell subsets will allow the further investigation of their anti-tumor reactivity. Ultimately, the enrichment and expansion of the identified tumor-reactive T cell population hold great promises to improve the efficiency of T cell therapy against cancer.Disclosure InformationE. Criado-Moronati: A. Employment (full or part-time); Significant; Miltenyi Biotec B.V. & Co. KG. A. Gosselink: A. Employment (full or part-time); Significant; Miltenyi Biotec B.V. & Co. KG. J. Kollet: A. Employment (full or part-time); Significant; Miltenyi Biotec B.V. & Co. KG. A. Dzionek: A. Employment (full or part-time); Significant; Miltenyi Biotec B.V. & Co. KG. B. Heemskerk: A. Employment (full or part-time); Significant; Miltenyi Biotec B.V. & Co. KG.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A132-A132
Author(s):  
Yan Zhang ◽  
Anna Kozlowska ◽  
Jacqueline Fritz ◽  
Yingying Zhao ◽  
Claudia Palomino La Torre ◽  
...  

BackgroundWhile CAR-T have demonstrated potent activity against hematologic tumors, less success has been seen with solid tumors. Here we report generation of TSCM-enriched allogeneic MUC1-C-specific CAR T cells, P-MUC1C-ALLO1, with potential for a broad range of solid tumors. The proliferative capacity and metabolic profile of TSCM CAR-T are well-suited to activity in the solid tumor setting. MUC1 is comprised of an N-terminal subunit (MUC1-N) tethered to a C-terminal subunit (MUC1-C), forming a stable complex on the cell surface. During tumorigenesis, MUC1 becomes both overexpressed and hypo-glycosylated on many carcinomas. Furthermore, MUC1 undergoes proteolytic cleavage in the tumor microenvironment, leaving behind a proteolytic ‘stump’ of MUC1-C that is over-represented in cancer, making it an attractive therapeutic target.MethodsP-MUC1C-ALLO1 is manufactured using the piggyBac® DNA Delivery System for CAR insertion and the Cas-CLOVER™ Gene Editing System to knockout both the TCR and MHC class I proteins. The addition of a selectable marker within the transposon allows for selection of a fully CAR-positive population while any residual TCR-positive cells are removed at the end of production to prevent TCR-mediated GvHD. Lastly, inclusion of a proprietary ‘booster molecule’ in our allogeneic process further improves cell expansion, along with phenotype and function, and enables the production of up to hundreds of patient doses from a single manufacturing run.ResultsSignificant doses of P-MUC1C-ALLO1 products made from multiple healthy donors were achieved and comprised of an exceptionally high-percentage of desirable TSCM cells. Preclinical evaluation of these products showed potent tumor killing and cytokine secretion against MUC1-C-positive breast and ovarian tumor cell lines. P-MUC1C-ALLO1 demonstrates potent cytotoxicity against tumor cells, and minimal killing of normal MUC1-C-positive human primary cells. In a triple negative breast cancer xenograft model, MUC1C CAR-T eliminated established MDA-MB-468 tumor cells, mounted robust T cell expansion in peripheral blood and maintained a favorable TSCM percentage over time. Likewise, in an orthotopic ovarian cancer xenograft model, intraperitoneally administered MUC1C CAR-T eliminated established OVCAR3 cells to levels below the limit of detection. All together, these data demonstrated the efficacy of the MUC1C CAR-T cells and the robustness of the allogeneic platform.ConclusionsP-MUC1C-ALLO1 is an allogeneic TSCM CAR-T therapy that has a potential to treat multiple MUC1-expressing indications. P-MUC1C-ALLO1 displayed specificity for tumor vs. normal cells as well as in vivo efficacy against xenograft models of breast and ovarian cancer. This allogeneic cell therapy is advancing rapidly towards the clinic.


2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e17075-e17075 ◽  
Author(s):  
Henning De May ◽  
Sharina Palencia Desai ◽  
Ichiko Kinjyo ◽  
Jaryse Harris ◽  
Sarah Foster Adams

e17075 Background: Despite the correlation between tumor infiltrating lymphocytes and long-term survival, immune-based therapies have underperformed for the treatment of ovarian cancer. This is attributed to an immune suppressive intraperitoneal microenvironment. With evidence that T cell dysfunction in the ovarian tumor environment is not reflected peripherally, we hypothesized that anatomically restricted T cell subsets play a role in local disease regulation. High expression of integrin α4 (CD49d) is selectively seen on peritoneal T cells in patients and healthy mice. Here we tested whether CD49d(high) CD8 T cells also contribute to anti-tumor immunity in ovarian cancer models. Methods: Using a syngeneic immune competent model of high grade serous ovarian cancer (ID8ova), we evaluated the phenotype of CD49d(high) T cells at varying stages of intraperitoneal disease by flow cytometry. Antigen specificity was tested using a SIINFEKL/H-2Kb NIH tetramer assay. Results: CD49d is highly expressed by peritoneal CD8 T cells but not by splenocytes in tumor-bearing mice (29.8% vs. 3.3% of CD8 cells respectively). Supporting a role in anti-tumor immunity, 92% of tumor antigen-specific CD8 T cells in the peritoneal cavity expressed high CD49d. While the proportion of peritoneal CD8 cells that express high CD49d is similar in healthy and tumor-bearing mice, CD49d(high)CD8 cells upregulate the expression of co-inhibitory receptors with tumor progression. At late stages of the disease, PD-1, TIM3, and LAG3 are exclusively expressed by peritoneal CD49d(high) cells (range 94.7 +/- 3.05%). Consistent with our prior data, PD1+TIM3+LAG3+ CD8 T cells were not present in the spleen, confirming the anatomic specificity of this lymphocyte subset. Conclusions: These findings add to the accumulating evidence that tumor immunity is locally regulated and identify an IP specific subset of CD8 T cells that could be selectively targeted with immune checkpoint blockade. We predict that strategies directing immune therapy to the peritoneal tumor microenvironment will enhance treatment efficacy and limit off-target toxicities in women with ovarian cancer.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A557-A557
Author(s):  
Julian Lum ◽  
Marisa Kilgour ◽  
Sarah MacPherson ◽  
Lauren Zacharias ◽  
Sarah Keyes ◽  
...  

BackgroundImmune regulatory metabolites are key features of the tumor microenvironment (TME), yet with a few exceptions, their identities remain largely unknown. Importantly, little is known about the heterogeneity of metabolites that are present or absent in specimens from human tumors and immune compartments.MethodsHere, we profiled tumor and T cells from tumor and ascites of patients with high-grade serous carcinoma (HGSC) to uncover the metabolomes of these distinct TME compartments. We devised a stringent and robust protocol to enrich cell populations from surgically resected samples in patients with HGSC. We conducted mass spectrometry-based analysis and developed machine learning tools to highlight novel metabolites that are present in different cellular lineages of the tumor.ResultsCells within the ascites and tumor had pervasive metabolite differences, with a striking enrichment in 1-methylnicotinamide (MNA) in T cells infiltrating the tumor compared to ascites. Despite the elevated levels of MNA in T cells, the expression of nicotinamide N-methyltransferase, the enzyme that catalyzes the transfer of a methyl group from S-adenosylmethionine to nicotinamide, was restricted to fibroblasts and tumor cells. T cells treated with MNA stimulated secretion of the tumor promoting cytokine tumor necrosis factor alpha.ConclusionsOur studies provide the first catalogue of metabolites in patient-derived tumors and T cells. We found that TME-derived MNA contributes to the immune modulation of T cells and represents a potential immunotherapy target to treat human cancer.Ethics ApprovalThis study was approved by the University of British Columbia and BC Cancer Research Ethics Board (H07-00463).ConsentWritten informed consent was obtained from the patient to use the results of this study for educational purposes including publications. A copy of the written consent is on file and available for review by the Editor of this journal.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4550-4550 ◽  
Author(s):  
Tsvetelina Pentcheva-Hoang ◽  
David Torres ◽  
Tania Rodriguez ◽  
Ana Korngold ◽  
An Lu ◽  
...  

Abstract Introduction: Use of T cells engineered to express antigen-specific T cell receptors (TCRs) has shown promise as a cancer immunotherapy treatment; however, durable responses have been limited by poor T cell persistence and expansion in vivo. Additionally, MHC class I downregulation on tumor cells further reduces therapeutic efficacy. Therefore, we co-expressed in human T cells a novel, small molecule dimerizer (rimiducid)-dependent T cell "activation switch", called inducible MyD88/CD40 (iMC), along with tumor antigen-specific TCRs to regulate T cell activation and expansion, while upregulating MHC class I expression on tumor cells. Methods: Human T cells were activated with anti-CD3/CD28 and transduced with g-retroviruses encoding TCR α and β chains recognizing either the cancer-testes antigen PRAME (HLA-A*201-restricted SLLQHLIGL) or the B cell-specific transcriptional co-activator, Bob1/OBF-1 (HLA-B*702-restricted APAPTAVVL). Parallel "GoTCR" vectors co-expressed the αβ TCR and iMC, comprising signaling domains from MyD88 and CD40 fused in-frame with tandem rimiducid-binding FKBP12v36 domains. Proliferation, cytokine production and cytotoxicity of modified T cells was assessed using peptide-pulsed EGFPluc-expressing T2 cells (PRAME only) or PRAME+/Bob1+, HLA-A2+ HLA-B7+ EGFPluc-expressing U266 myeloma cells ± rimiducid (10 nM). MHC class I upregulation on tumor cells was measured using transwell assays and flow cytometry. In vitro tumor killing and T cell proliferation were analyzed using T cell and tumor coculture assays by either measuring loss of luciferase activity overnight or by flow cytometry over a period of 4-7 days. Finally, in vivo efficacy was determined using immune-deficient NSG mice engrafted i.v. with U266 cells and treated i.v. with 5x106-1x107 transduced T cells. iMC was activated in vivo by weekly or biweekly i.p. rimiducid injections (1-5 mg/kg). Tumor size and T cell expansion was measured using in vivo bioluminescence imaging and flow cytometry, respectively. Results: All vectors efficiently (~85%) transduced activated T cells and showed antigen-specific IFN-g production and cytolytic function against peptide-pulsed T2 cells and/or PRAME+Bob1+ U266 myeloma cells. However, both TCR ligation and rimiducid-dependent iMC costimulation were required for IL-2 production against PRAME peptide-pulsed T2 cells. Coculture assays against U266 cells showed that tumor elimination was optimized with concurrent rimiducid-driven iMC activation in both "GoPRAME" and "GoBob1" constructs, and this was accompanied by greatly increased IL-2 secretion and robust T cell proliferation (~ 50-fold vs PRAME or Bob1-specific TCRs alone). Further, iMC activation produced IFN-g independently of TCR ligation, which significantly increased MHC class I expression on tumor cells (~ 7-fold) relative to PRAME TCR-transduced T cells. In NSG mice engrafted with PRAME+ U266 myeloma tumors, GoPRAME TCR-modified T cells persisted for at least 81 days post-injection and prevented tumor growth, unlike any of the other T cell groups. Importantly, weekly rimiducid injection dramatically expanded iMC-PRAME TCR-expressing T cell numbers by ~1000-fold on day 81 post-injection compared to T cells expressing only the PRAME TCR (p < 0.001). Summary: iMC is a novel "Go" switch that utilizes rimiducid, a small molecule dimerizer, to provide costimulation to PRAME and Bob1-specific TCR-engineered T cells while sensitizing tumors to TCR-mediated recognition via cytokine-induced MHC I upregulation. These iMC-enhanced TCRs are prototypes of novel "GoTCR" engineered T cell therapies that may increase efficacy, safety and durability of adoptive T cell therapies. Disclosures Pentcheva-Hoang: Bellicum Pharmaceuticals: Employment. Torres:Bellicum Pharmaceuticals: Employment. Rodriguez:Bellicum Pharmaceuticals: Employment. Korngold:Bellicum Pharmaceuticals: Employment. Lu:Bellicum Pharmaceuticals: Employment. Crisostomo:Bellicum Pharmaceuticals: Employment. Moseley:Bellicum Pharmaceuticals: Employment, Membership on an entity's Board of Directors or advisory committees. Slawin:Bellicum Pharmaceuticals: Employment, Equity Ownership. Spencer:Bellicum Pharmaceuticals: Employment, Equity Ownership. Foster:Bellicum Pharmaceuticals: Employment.


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