513 CD26 enzymatic activity modulates efficient migration of adoptively transferred T cells to solid tumors

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A549-A549
Author(s):  
Megan Wyatt ◽  
Stefanie Bailey ◽  
Michelle Nelson ◽  
Hannah Knochelmann ◽  
Aubrey Smith ◽  
...  
Keyword(s):  
T Cells ◽  
Enzymatic Activity ◽  
Solid Tumors ◽  
Study Endpoint ◽  
Melanoma Tumor ◽  
Antitumor Response ◽  
Migration Assay ◽  
Specific Subset ◽  
Donor Cells

BackgroundThe inadequate ability of adoptively transferred T cells to eradicate solid tumors limits their use in treatments for patients afflicted with those cancers. Efforts to improve ACT for solid tumors aim to identify strategies that poise T cells for optimal response. We have previously identified a specific subset of CD4 T cells which express high levels of the ubiquitous ectoenzyme dipeptidyl peptidase-4 (DPP-4), also known as CD26, that produce a tremendous antitumor response in solid tumor models. We therefore sought to investigate the importance of CD26 on T cells destined for ACT.MethodsWe adoptively transferred tumor specific CD26+ T cells into melanoma tumor-bearing CD26-/- mice, and continuously blocked the CD26 enzymatic activity of the donor cells in vivo with sitagliptin, an established competitive inhibitor of CD26.ResultsTumors in sitagliptin-treated mice eventually reached study endpoint, while tumors untreated mice were regressed for 130+ days. Tumor infiltration of donor cells and host CD8 and CD4 cells was diminished with sitagliptin treatment. A 32-plex cytokine array of blood plasma revealed a diminished profile of cytokines and chemokines, indicating that the inflammatory response of the T cells was dampened with sitagliptin treatment. Further experiments characterized the ability of CD26+ T cells to respond to tumor trafficking signals with a transwell migration assay and found that sitagliptin treatment significantly impaired their migratory capacity. However, sitagliptin did not impair the ability of T cells to functionally respond to antigen.ConclusionsThese data suggest that the enzymatic activity of CD26 is important for the ability of T cells to migrate to the tumor site in order to mount an effective antitumor response. Further investigations into the mechanism behind the role of CD26 are ongoing.Ethics ApprovalThis study was approved by the Medical University of South Carolina’s IACUC, protocol #00488

scholarly journals Metabolic radiolabeling and in vivo PET imaging of cytotoxic T lymphocytes to guide combination adoptive cell transfer cancer therapy

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Dehua Lu ◽  
Yanpu Wang ◽  
Ting Zhang ◽  
Feng Wang ◽  
Kui Li ◽  
...  
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Solid Tumors ◽  
Cytotoxic T Lymphocytes ◽  
Pet Imaging ◽  
Stage Migration ◽  
Cell Transfer ◽  
Tumor Infiltration ◽  
Antitumor Effects

Abstract Background Adoptive T cell transfer-based immunotherapy yields unsatisfactory results in the treatment of solid tumors, partially owing to limited tumor infiltration and the immunosuppressive microenvironment in solid tumors. Therefore, strategies for the noninvasive tracking of adoptive T cells are critical for monitoring tumor infiltration and for guiding the development of novel combination therapies. Methods We developed a radiolabeling method for cytotoxic T lymphocytes (CTLs) that comprises metabolically labeling the cell surface glycans with azidosugars and then covalently conjugating them with 64Cu-1,4,7-triazacyclononanetriacetic acid-dibenzo-cyclooctyne (64Cu-NOTA-DBCO) using bioorthogonal chemistry. 64Cu-labeled control-CTLs and ovalbumin-specific CTLs (OVA-CTLs) were tracked using positron emission tomography (PET) in B16-OVA tumor-bearing mice. We also investigated the effects of focal adhesion kinase (FAK) inhibition on the antitumor efficacy of OVA-CTLs using a poly(lactic-co-glycolic) acid (PLGA)-encapsulated nanodrug (PLGA-FAKi). Results CTLs can be stably radiolabeled with 64Cu with a minimal effect on cell viability. PET imaging of 64Cu-OVA-CTLs enables noninvasive mapping of their in vivo behavior. Moreover, 64Cu-OVA-CTLs PET imaging revealed that PLGA-FAKi induced a significant increase in OVA-CTL infiltration into tumors, suggesting the potential for a combined therapy comprising OVA-CTLs and PLGA-FAKi. Further combination therapy studies confirmed that the PLGA-FAKi nanodrug markedly improved the antitumor effects of adoptive OVA-CTLs transfer by multiple mechanisms. Conclusion These findings demonstrated that metabolic radiolabeling followed by PET imaging can be used to sensitively profile the early-stage migration and tumor-targeting efficiency of adoptive T cells in vivo. This strategy presents opportunities for predicting the efficacy of cell-based adoptive therapies and for guiding combination regimens. Graphic Abstract

scholarly journals Cereblon harnesses Myc-dependent bioenergetics and activity of CD8+ T lymphocytes

Blood ◽  
2020 ◽  
Vol 136 (7) ◽  
pp. 857-870
Author(s):  
Rebecca S. Hesterberg ◽  
Matthew S. Beatty ◽  
Ying Han ◽  
Mario R. Fernandez ◽  
Afua A. Akuffo ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Ex Vivo ◽  
Cytolytic Activity ◽  
Central Metabolism ◽  
Melanoma Tumor ◽  
Drug Induced ◽  
Cell Effector

Abstract Immunomodulatory drugs, such as thalidomide and related compounds, potentiate T-cell effector functions. Cereblon (CRBN), a substrate receptor of the DDB1-cullin-RING E3 ubiquitin ligase complex, is the only molecular target for this drug class, where drug-induced, ubiquitin-dependent degradation of known “neosubstrates,” such as IKAROS, AIOLOS, and CK1α, accounts for their biological activity. Far less clear is whether these CRBN E3 ligase-modulating compounds disrupt the endogenous functions of CRBN. We report that CRBN functions in a feedback loop that harnesses antigen-specific CD8+ T-cell effector responses. Specifically, Crbn deficiency in murine CD8+ T cells augments their central metabolism manifested as elevated bioenergetics, with supraphysiological levels of polyamines, secondary to enhanced glucose and amino acid transport, and with increased expression of metabolic enzymes, including the polyamine biosynthetic enzyme ornithine decarboxylase. Treatment with CRBN-modulating compounds similarly augments central metabolism of human CD8+ T cells. Notably, the metabolic control of CD8+ T cells by modulating compounds or Crbn deficiency is linked to increased and sustained expression of the master metabolic regulator MYC. Finally, Crbn-deficient T cells have augmented antigen-specific cytolytic activity vs melanoma tumor cells, ex vivo and in vivo, and drive accelerated and highly aggressive graft-versus-host disease. Therefore, CRBN functions to harness the activation of CD8+ T cells, and this phenotype can be exploited by treatment with drugs.

scholarly journals In-Vivo Detection and Tracking of T Cells in Various Organs in a Melanoma Tumor Model by 19F-Fluorine MRS/MRI

PLoS ONE ◽  
2016 ◽  
Vol 11 (10) ◽  
pp. e0164557 ◽  
Author(s):  
Christine Gonzales ◽  
Hikari A. I. Yoshihara ◽  
Nahzli Dilek ◽  
Julie Leignadier ◽  
Melita Irving ◽  
...  
Keyword(s):  
T Cells ◽  
Tumor Model ◽  
Melanoma Tumor ◽  
Detection And Tracking ◽  
In Vivo Detection

scholarly journals Tracking Adoptive T Cell Therapy Using Magnetic Particle Imaging

2020 ◽  
Author(s):  
Angelie Rivera-Rodriguez ◽  
Lan B. Hoang-Minh ◽  
Andreina Chiu-Lam ◽  
Nicole Sarna ◽  
Leyda Marrero-Morales ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Solid Tumors ◽  
Magnetic Particle ◽  
Ex Vivo ◽  
Intraventricular Administration ◽  
Magnetic Particle Imaging ◽  
Particle Imaging ◽  
The Brain

ABSTRACTAdoptive cellular therapy (ACT) is a potent strategy to boost the immune response against cancer. ACT is an effective treatment for blood cancers, such as leukemias and lymphomas, but faces challenges treating solid tumors and cancers in locations like the brain. A critical step for success of ACT immunotherapy is achieving efficient trafficking of T cells to solid tumors, and the non-invasive and quantitative tracking of adoptively transferred T cell biodistribution would accelerate its development. Here, we demonstrate the use of Magnetic Particle Imaging (MPI) to non-invasively track ACT T cells in vivo. Labeling T cells with the superparamagnetic iron oxide nanoparticle tracer ferucarbotran did not affect T cell viability, phenotype, or cytotoxic function in vitro. Following ACT, ferucarbotran-labeled T cells were detected and quantified using MPI ex vivo and in vivo, in a mouse model of invasive brain cancer. Proof-of-principle in vivo MPI demonstrated its capacity to detect labeled T cells in lungs and liver after intravenous administration and to monitor T cell localization in the brain after intraventricular administration. Ex vivo imaging using MPI and optical imaging suggests accumulation of systemically administered ferucarbotran-labeled T cells in the brain, where MPI signal from ferucarbotran tracers and fluorescently tagged T cells were observed. Ex vivo imaging also suggest differential accumulation of nanoparticles and viable T cells in other organs like the spleen and liver. These results support the use of MPI to track adoptively transferred T cells and accelerate the development of ACT treatments for brain tumors and other cancers.

scholarly journals PD-L1 chimeric costimulatory receptor improves the efficacy of CAR-T cells for PD-L1-positive solid tumors and reduces toxicity in vivo

2020 ◽  
Author(s):  
Qibin Liao ◽  
Yunyu Mao ◽  
Huan He ◽  
Xiangqing Ding ◽  
Xiaoyan Zhang ◽  
...  
Keyword(s):  
T Cells ◽  
Solid Tumors ◽  
Jurkat T Cells ◽  
Costimulatory Receptor ◽  
Car T Cells ◽  
Car T ◽  
Engineered T Cells ◽  
Therapeutic Safety

Abstract Background: On-target off-tumor toxicity impedes the clinical application of chimeric antigen receptor-modified T cells (CAR-T cells) in the treatment of solid tumors. The combinatorial antigen recognition strategy can improve the therapeutic safety of CAR-T cells by targeting two different tumor-associated antigens (TAAs) using a CAR and a chimeric costimulatory receptor (CCR). Although programmed death-ligand 1 (PD-L1, also known as B7-H1) is expressed on multiple tumors, the potential of PD-L1 as a universal target for designing CCR remains unknown.Methods: A first-generation CD19 or HER2 CAR and a PD-L1 CCR containing the CD28 signaling domain were constructed and delivered into Jurkat T cells or primary T cells by a pseudotyped lentivirus. The release of cytokines, including IL-2, IFN-γ and TNF-α, was quantified using enzyme-linked immunosorbent assay (ELISA) kits or a cytometric bead array (CBA). The in vitro cytotoxicity of CAR-T cells was detected with a luciferase-based killing assay. The in vitro proliferation of CAR-T cells was assessed by flow cytometry. The therapeutic safety and efficacy of CAR-T cells was evaluated using a subcutaneous dual-tumor model in vivo.Results: Jurkat T cells or primary T cells expressing both the CD19/HER2 CAR and PD-L1 CCR produced higher levels of cytokines in the presence of CD19/HER2 and PD-L1 than in the presence of HER2/CD19. Compared to HER2-z-engineered T cells, HER2-z-PD-L1-28-engineered T cells had higher in vitro cytotoxicity potential against PD-L1-positive tumor cells. CD19/HER2-z-PD-L1-28-engineered T cells showed higher proliferation potential in the presence of CD19/HER2 and PD-L1 than in the absence of PD-L1. CD19/HER2-z-PD-L1-28-engineered T cells preferably destroyed xenograft tumors expressing CD19/HER2 and PD-L1 in vivo and did not significantly affect CD19/HER2-expressing tumors. The PD-L1 CCR improved the antitumor efficacy of low-affinity HER2 CAR-T cells against PD-L1-positive tumors expressing high levels of HER2.Conclusion: Our findings confirmed that PD-L1 can be used as a universal target antigen for designing CCR, improving the efficacy of CAR-T cells in the treatment of PD-L1-positive solid tumors but reducing toxicity within PD-L1-negative normal tissues expressing low levels of TAA in vivo.

scholarly journals NTLA5001, a T Cell Product Candidate with CRISPR-Based Targeted Insertion of a High-Avidity, Natural, WT1-Specific TCR, Shows Efficacy in In Vivo Models of AML and ALL

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 32-33
Author(s):  
Eliana Ruggiero ◽  
Dai Liu ◽  
Aaron Prodeus ◽  
Amy M Becker ◽  
Maxwell Foisey ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Board Of Directors ◽  
Solid Tumors ◽  
Cell Engineering ◽  
High Avidity ◽  
Engineering Process ◽  
Advisory Committees ◽  
Nog Mice

Adoptive cell therapy using T cells expressing transgenic (tg) tumor antigen-targeting T cell receptors (TCRs) has become an attractive modality to treat hematological and solid cancers due to a broader array of accessible targets relative to CAR-T cell therapies. However, high-avidity TCRs specific for shared oncogenic antigens are difficult to identify. In addition, manufacturing of TCR-redirected T cells with single TCR specificity is desired to avoid mispairings and competition with endogenous chains, which can negatively impact T cell specificity and TCR expression levels. This can be achieved with CRISPR/Cas9-mediated replacement of the endogenous TCR α and β chains, by knocking out the TRAC and TRBC genes and inserting the tgTCR into the TRAC locus. While CRISPR/Cas9 genome editing has been demonstrated to be highly efficient, simultaneous edits in different loci could result in increased translocations, potentially impairing the quality and safety of the cell product. Moreover, existing cell engineering technology negatively impacts T cell quality and yield. Here, we focused on engineering T cells with specificity for Wilms' Tumor 1 (WT1), a transcription factor overexpressed by a wide range of hematological and solid tumors, that has both, restricted expression on healthy tissues and a strong correlation with oncogenesis. By applying rapid isolation technologies of WT1-specific T cells from healthy donors, we identified a lead TCR to the WT137-45 epitope, restricted to the common human leukocyte antigen, HLA-A*02:01. T cells expressing this tgTCR showed nM avidity and killed leukemia cell lines and primary acute myeloid leukemia (AML) blasts at low effector-to-target cell ratios. Epitope specificity evaluation by alanine scanning suggested that the minimal peptide recognition sequence for this TCR is restricted to WT1. Further, the lead TCR was able to activate CD8+ and CD4+ T cells, which may be beneficial for T cell persistence. By developing an improved T cell engineering process, we have achieved multiple sequential gene edits in primary human T cells, leading to knockout of the endogenous TCR with up to 99% efficiency and insertion of tgTCRs into 55-80% of the cells. This cell engineering process is scalable, adaptable to a closed system, and results in marked improvements in T cell expansion, yield, stem cell memory phenotype and T cell polyfunctionality, such as cytotoxicity, cytokine release and proliferation in response to WT1+ target cells. Additionally, the high viability profile of the process readily allows for sequential CRISPR/Cas9 gene knockout in T cells, leading to near-complete endogenous TCR removal while limiting TRAC/TRBC translocation to levels close to those found in untreated cells. T cells engineered to express the lead TCR using this process resulted in potent anti-tumor activity in vivo. Disseminated primary AML patient derived xenograft and acute lymphoblastic leukemia (ALL) cell line models were established by intravenous injection of the tumor cells in NSG or NOG mice. Animals were treated subsequently with WT1-specific or control T cells. Almost complete tumor growth inhibition in the blood and bone marrow was noted in the primary AML model. In the fast growing ALL model, WT1-T cells significantly reduced tumor burden and increased survival compared to control groups, which could be further boosted in human IL-15-expressing NOG mice vs. standard NOG mice. No signs of graph-versus-host disease (GvHD) were observed during the course of the study, which is consistent with removal of the endogenous TCR. NTLA-5001 is being advanced into clinical development for AML immunotherapy. Given the expression of WT1 in many solid tumors, engineered WT1 TCR-T cells are being further explored in those indications. Disclosures Liu: Intellia Therapeutics: Current Employment. Prodeus:Intellia Therapeutics: Current Employment. Becker:Intellia Therapeutics: Current Employment. Foisey:Intellia Therapeutics: Current Employment. Balwani:Intellia Therapeutics: Current Employment. Dutta:Intellia Therapeutics: Current Employment. Zhang:Intellia Therapeutics: Current Employment. Arredouani:Intellia Therapeutics: Current Employment. McKee:Intellia Therapeutics: Current Employment. Ciceri:Intellia Therapeutics: Membership on an entity's Board of Directors or advisory committees. Sepp-Lorenzino:Intellia Therapeutics: Current Employment. Bonini:Kiadis: Membership on an entity's Board of Directors or advisory committees; Kite/Gilead: Membership on an entity's Board of Directors or advisory committees; Molmed: Membership on an entity's Board of Directors or advisory committees; Allogene: Membership on an entity's Board of Directors or advisory committees; Intellia Therapeutics: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Schultes:Intellia Therapeutics: Current Employment, Current equity holder in publicly-traded company.

173 An in vivo CRISPR/Cas9 screening platform to identify T cell enhancing edits in distinct solid tumor microenvironments

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A187-A187
Author(s):  
Amy Becker ◽  
Troy Luster ◽  
Ishina Balwani ◽  
Nachiket Shevale ◽  
Jingwei Sun ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Solid Tumors ◽  
Model Systems ◽  
Mouse Tumor ◽  
Target Discovery ◽  
Knock Out ◽  
Cell Therapies ◽  
Screening Platform

BackgroundChimeric antigen receptor (CAR)-based T cell therapy and other forms of adoptive cell therapies (ACTs) have shown remarkable success in the treatment of hematologic malignancies; however, reports of clinical activity in solid tumors are limited to date. One key therapeutic challenge presented by solid tumors is the immunosuppressive tumor microenvironment (TME). Adding to the complexity, it is becoming increasingly clear that TMEs are heterogeneous (broadly classified as ‘inflamed,’ ‘immune excluded’ and ‘immune dessert’), utilizing different mechanisms of immunosuppression. Instrumental to overcoming the barriers presented by solid tumors will be the development of T cells with immune- enhancing edits that improve penetration, potency and persistence, while also preventing exhaustion in hostile TMEs. T cells with these properties may help in the development of ACTs in solid tumors.MethodsCRISPR/Cas9-based functional genetic screens in T cells can enable prioritization of known targets and uncover novel targets to improve the design of genetically reprogrammed cell therapies, in an unbiased fashion. Most CRISPR screens to date have been performed in vitro with tumor cells due to the complexity of setting up CRISPR screens in primary T cells, particularly for in vivo target discovery. Here, we describe the development and careful optimization of an in vivo mouse CRISPR-screening platform to identify knock-out targets in primary T cells, with the goal of increasing T cell abundance and persistence in tumors with different TMEs. Using a mouse retroviral system to express single-guide RNA (sgRNA) libraries in T cells from Cas9 transgenic mice, we performed in vivo screens in syngeneic, fully immune-competent mouse tumor models.ResultsWe identified both known and potential novel regulators of T cell activation and persistence. Importantly, we have discovered knock-out targets that accumulate in multiple, distinct TMEs and other targets that are TME-specific. The use of sub-genomic- focused libraries allowed us to rapidly screen in multiple tumor model systems and reproducibly identify hits across individual mice.ConclusionsWe have developed a fully optimized an in vivo genetic screen, which could be a rich source for target discovery, and can enable identification of functional regulators of T cells for rapid incorporation into CRISPR-engineered T cell therapies for different solid TMEs.

scholarly journals Chemotaxis of Vδ2 T cells to the joints contributes to the pathogenesis of rheumatoid arthritis

2017 ◽  
Vol 76 (12) ◽  
pp. 2075-2084 ◽  
Author(s):  
Wen-Xiu Mo ◽  
Shan-Shan Yin ◽  
Hua Chen ◽  
Chen Zhou ◽  
Jia-Xin Zhou ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Flow Cytometry ◽  
T Cells ◽  
Disease Activity ◽  
Chemokine Receptors ◽  
Interferon Γ ◽  
Receptor Expression ◽  
Migration Assay ◽  
Tnf Α

ObjectivesTo explore the role of Vδ2 T cells in the pathogenesis of rheumatoid arthritis (RA).MethodsSixty-eight patients with RA, 21 patients with osteoarthritis and 21 healthy controls were enrolled in the study. All patients with RA fulfilled the 2010 American College of Rheumatology/European League Against Rheumatism criteria for RA. Peripheral Vδ2T population, chemokine receptor expression and proinflammatory cytokine secretion were quantified by flow cytometry. The infiltration of Vδ2 T cells within the synovium was examined by immunohistochemistry and flow cytometry. The effect of tumour necrosis factor (TNF)-α and interleukin (IL)-6 on Vδ2 T migration was determined by flow cytometry and transwell migration assay.ResultsPeripheral Vδ2T cells, but not Vδ1 T cells, were significantly lower in patients with RA, which was negatively correlated with disease activity gauged by Disease Activity Score in 28 joints. Vδ2 T cells from RA accumulated in the synovium and produced high levels of proinflammatory cytokines including interferon-γ and IL-17. Phenotypically, Vδ2 T cells from RA showed elevated chemotaxis potential and expressed high levels of chemokine receptors CCR5 and CXCR3, which was driven by increased serum TNF-α through nuclear factor kappa B signalling. In vivo, TNF-α neutralising therapy dramatically downregulated CCR5 and CXCR3 on Vδ2 T cells and repopulated the peripheral Vδ2 T cells in patients with RA.ConclusionsHigh levels of TNF-α promoted CCR5 and CXCR3 expression in Vδ2 T cells from RA, which potentially infiltrated into the synovium and played crucial roles in the pathogenesis of RA. Targeting Vδ2 T cells might be a potential approach for RA.

scholarly journals Cd8+ but Not Cd8− Dendritic Cells Cross-Prime Cytotoxic T Cells in Vivo

2000 ◽  
Vol 192 (12) ◽  
pp. 1685-1696 ◽  
Author(s):  
Joke M.M. den Haan ◽  
Sophie M. Lehar ◽  
Michael J. Bevan
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Mhc Class I ◽  
Cytotoxic T Lymphocyte ◽  
Cytotoxic T Cells ◽  
Class I ◽  
Specific Subset ◽  
Mhc Class I Molecules

Bone marrow–derived antigen-presenting cells (APCs) take up cell-associated antigens and present them in the context of major histocompatibility complex (MHC) class I molecules to CD8+ T cells in a process referred to as cross-priming. Cross-priming is essential for the induction of CD8+ T cell responses directed towards antigens not expressed in professional APCs. Although in vitro experiments have shown that dendritic cells (DCs) and macrophages are capable of presenting exogenous antigens in association with MHC class I, the cross-presenting cell in vivo has not been identified. We have isolated splenic DCs after in vivo priming with ovalbumin-loaded β2-microglobulin–deficient splenocytes and show that they indeed present cell-associated antigens in the context of MHC class I molecules. This process is transporter associated with antigen presentation (TAP) dependent, suggesting an endosome to cytosol transport. To determine whether a specific subset of splenic DCs is involved in this cross-presentation, we negatively and positively selected for CD8− and CD8+ DCs. Only the CD8+, and not the CD8−, DC subset demonstrates cross-priming ability. FACS® studies after injection of splenocytes loaded with fluorescent beads showed that 1 and 0.6% of the CD8+ and the CD8− DC subsets, respectively, had one or more associated beads. These results indicate that CD8+ DCs play an important role in the generation of cytotoxic T lymphocyte responses specific for cell-associated antigens.

scholarly journals 714 PD1 x TGFβR2 bispecifics selectively block TGFβR2 on PD1-positive T cells, promote T cell activation, and elicit an anti-tumor response in solid tumors

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A756-A756
Author(s):  
Gregory Moore ◽  
Suzanne Schubbert ◽  
Christine Bonzon ◽  
Kendra Avery ◽  
Rumana Rashid ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Solid Tumors ◽  
T Cell Activation ◽  
Tumor Response ◽  
Nsg Mice ◽  
Pd1 Blockade ◽  
Anti Tumor Activity

BackgroundTGFβ production by solid tumors and their microenvironment is a major mechanism used by tumors to avoid immunosurveillance. Blockade of TGFβ has been shown to promote an anti-tumor response; however, systemic blockade of TGFβ has also been associated with toxicity. We hypothesized that a PD1 x TGFβR2 bispecific antibody could selectively block the suppressive activity of TGFβ on tumor T cells and enhance their anti-tumor activity while avoiding the toxicity associated with systemic blockade.MethodsWe engineered bispecific antibodies that simultaneously engage PD1 and TGFβR2 using Xencor’s XmAb platform. The anti-TGFβR2 arm was tuned for optimal activity by introducing affinity-modulating amino acid substitutions. The activity of PD1 x TGFβR2 bispecifics was evaluated in vitro using a signaling assay to measure phosphorylated SMAD (pSMAD) by flow cytometry with exogenous TGFβ in unactivated and activated PBMC. In vivo activity was evaluated by monitoring the engraftment of human PBMC in NSG mice (huPBMC-NSG). Anti-tumor activity was assessed in huPBMC-NSG mice engrafted with established human cancer cell lines. Antibodies against other T cell targets were also incorporated into TGFβR2 bispecifics, and similarly evaluated in vitro and in vivo.ResultsPD1 x TGFβR2 bispecifics were confirmed to bind PD1 and block binding of TGFβ to TGFβR2. In vitro, we found that T cells from activated, serum-deprived PBMC exhibited robust induction of pSMAD in response to TGFβ, and PD1 x TGFβR2 bispecifics selectively inhibited pSMAD induction in PD1-positive T cells as demonstrated by over a 100-fold potency increase compared to an untargeted anti-TGFβR2 control. Additionally, we saw an enhancement of potency when evaluating blocking activity in activated (PD1-high) vs. unactivated (PD1-low) T cells. Similar selectivity was measured when comparing inhibition of pSMAD induction for activated T cells versus other PD1-negative, TGFβ-responsive immune cells. Intriguingly, TGFβR2 bispecifics incorporating antibodies against other T cell targets allowed for the targeting of a broader population of T cells while still conferring potent selectivity against target-negative cells. In vivo, treatment of huPBMC-NSG mice with TGFβR2 bispecifics promoted superior T cell engraftment and combined additively with PD1 blockade. Furthermore, TGFβR2 bispecific treatment of huPBMC-NSG mice containing established MDA-MB-231 triple-negative breast cancer tumors promoted an anti-tumor response that was also augmented with PD1 blockade.ConclusionsMultiple PD1 x TGFβR2 bispecifics were engineered to selectively block TGFβR2 on PD1-positive T cells and evaluated in vitro and in vivo. Compelling activity, including additivity with PD1 blockade, suggests that clinical development is warranted for the treatment of human malignancies.

Sign in / Sign up

Export Citation Format

Share Document