Project description:CAR-T cell therapy is effective in hematologic malignancies but not in solid tumors. In breast and lung cancer patients, CAR-T cells targeting ROR1 infiltrated tumors poorly and became dysfunctional. To test strategies for enhancing efficacy, we induced ROR1+ lung tumors in KrasLSL-G12D/+;p53fl/f mice. Murine ROR1 CAR-T cells transferred after lymphodepletion with cyclophosphamide (Cy) transiently controlled tumor growth but infiltrated tumors poorly and lost function, as observed in patients. Adding oxaliplatin (Ox) to the lymphodepletion regimen activated tumor macrophages to express T cell-recruiting chemokines, resulting in improved CAR-T cell infiltration, remodeling of the tumor microenvironment, and increased tumor sensitivity to anti-PD-L1. Combination therapy with Ox/Cy and anti-PD-L1 synergistically improved CAR-T mediated tumor control and survival, providing a strategy to improve CAR-T cell efficacy in the clinic.
Project description:CAR-T cell therapy is effective in hematologic malignancies but not in solid tumors. In breast and lung cancer patients, CAR-T cells targeting ROR1 infiltrated tumors poorly and became dysfunctional. To test strategies for enhancing efficacy, we induced ROR1+ lung tumors in KrasLSL-G12D/+;p53fl/f mice. Murine ROR1 CAR-T cells transferred after lymphodepletion with cyclophosphamide (Cy) transiently controlled tumor growth but infiltrated tumors poorly and lost function, as observed in patients. Adding oxaliplatin (Ox) to the lymphodepletion regimen activated tumor macrophages to express T cell-recruiting chemokines, resulting in improved CAR-T cell infiltration, remodeling of the tumor microenvironment, and increased tumor sensitivity to anti-PD-L1. Combination therapy with Ox/Cy and anti-PD-L1 synergistically improved CAR-T mediated tumor control and survival, providing a strategy to improve CAR-T cell efficacy in the clinic.
Project description:Targeting the PD-1/PD-L1 axis has transformed the field of immune-oncology. While conventional wisdom initially postulated that PD-L1 serves as the inert ligand for PD-1, an emerging body of literature suggests that PD-L1 has cell‑intrinsic functions in immune and cancer cells. In line with these studies, here we show that PD-L1 potently inhibits the type I interferon pathway in cancer cells. Hampered type I interferon responses in PD-L1-expressing cells resulted in enhanced infection with oncolytic viruses in cancer cells in vitro and in vivo. PD-L1 expression marks tumor explants from cancer patients that are best infected by oncolytic viruses. Agonistic antibodies targeting PD-L1 further reduced type I IFN responses and enhanced oncolytic virus infection. Mechanistically, PD-L1 suppressed type I interferon by promoting Warburg metabolism, characterized by enhanced glucose uptake and glycolysis rate. Lactate generated from glycolysis was the key metabolite responsible for inhibiting type I interferon responses and enhancing oncolytic virus infection in PD‑L1‑expressing cells. In addition to adding mechanistic insight into PD-L1 intrinsic function and showing that PD-L1 has a broader impact on immunity and cancer biology besides acting as a ligand for PD-1, our results will also help guide the numerous efforts currently ongoing to combine PD-L1 antibodies with oncolytic virotherapy in clinical trials.
Project description:CAR-T therapy has shown limited synergy with PD-1/PD-L1 blockade, but the mechanisms underlying resistance remain unclear. PD-1⁺TCF1⁺ stem-like T cells mediate responses to PD-1/PD-L1 blockade and are maintained by MHC-dependent interactions with DCs in tumor-draining lymph nodes (dLN). Because CAR-Ts recognize intact antigen, not peptide-MHC, their activation is confined to tumors, potentially preventing maintenance of this critical subset. In ROR1⁺ lung cancer models, ROR1-targeting CAR-Ts rapidly down-regulated TCF1, became exhausted, and were not enhanced by PD-L1 blockade. Overexpression of the AP-1 transcription factor c-Jun, but not BATF, enabled formation of PD-1⁺TCF1⁺ reservoirs in tumors, not dLN, but did not prevent exhaustion, as PD-1 induced post-transcriptional c-Jun down-regulation. Remarkably, PD-L1 blockade restored c-Jun levels, dramatically increased CAR-Ts, and enabled near-complete ROR1+ tumor clearance. These findings identify PD-1 as a suppressor of c-Jun and reveal that MHC-independent CAR-Ts can be engineered to establish intratumoral stem-like reservoirs that overcome resistance to PD-1 blockade.
Project description:CAR-T therapy has shown limited synergy with PD-1/PD-L1 blockade, but the mechanisms underlying resistance remain unclear. PD-1⁺TCF1⁺ stem-like T cells mediate responses to PD-1/PD-L1 blockade and are maintained by MHC-dependent interactions with DCs in tumor-draining lymph nodes (dLN). Because CAR-Ts recognize intact antigen, not peptide-MHC, their activation is confined to tumors, potentially preventing maintenance of this critical subset. In ROR1⁺ lung cancer models, ROR1-targeting CAR-Ts rapidly down-regulated TCF1, became exhausted, and were not enhanced by PD-L1 blockade. Overexpression of the AP-1 transcription factor c-Jun, but not BATF, enabled formation of PD-1⁺TCF1⁺ reservoirs in tumors, not dLN, but did not prevent exhaustion, as PD-1 induced post-transcriptional c-Jun down-regulation. Remarkably, PD-L1 blockade restored c-Jun levels, dramatically increased CAR-Ts, and enabled near-complete ROR1+ tumor clearance. These findings identify PD-1 as a suppressor of c-Jun and reveal that MHC-independent CAR-Ts can be engineered to establish intratumoral stem-like reservoirs that overcome resistance to PD-1 blockade.
Project description:CAR-T therapy has shown limited synergy with PD-1/PD-L1 blockade, but the mechanisms underlying resistance remain unclear. PD-1⁺TCF1⁺ stem-like T cells mediate responses to PD-1/PD-L1 blockade and are maintained by MHC-dependent interactions with DCs in tumor-draining lymph nodes (dLN). Because CAR-Ts recognize intact antigen, not peptide-MHC, their activation is confined to tumors, potentially preventing maintenance of this critical subset. In ROR1⁺ lung cancer models, ROR1-targeting CAR-Ts rapidly down-regulated TCF1, became exhausted, and were not enhanced by PD-L1 blockade. Overexpression of the AP-1 transcription factor c-Jun, but not BATF, enabled formation of PD-1⁺TCF1⁺ reservoirs in tumors, not dLN, but did not prevent exhaustion, as PD-1 induced post-transcriptional c-Jun down-regulation. Remarkably, PD-L1 blockade restored c-Jun levels, dramatically increased CAR-Ts, and enabled near-complete ROR1+ tumor clearance. These findings identify PD-1 as a suppressor of c-Jun and reveal that MHC-independent CAR-Ts can be engineered to establish intratumoral stem-like reservoirs that overcome resistance to PD-1 blockade.
Project description:CAR-T therapy has shown limited synergy with PD-1/PD-L1 blockade, but the mechanisms underlying resistance remain unclear. PD-1⁺TCF1⁺ stem-like T cells mediate responses to PD-1/PD-L1 blockade and are maintained by MHC-dependent interactions with DCs in tumor-draining lymph nodes (dLN). Because CAR-Ts recognize intact antigen, not peptide-MHC, their activation is confined to tumors, potentially preventing maintenance of this critical subset. In ROR1⁺ lung cancer models, ROR1-targeting CAR-Ts rapidly down-regulated TCF1, became exhausted, and were not enhanced by PD-L1 blockade. Overexpression of the AP-1 transcription factor c-Jun, but not BATF, enabled formation of PD-1⁺TCF1⁺ reservoirs in tumors, not dLN, but did not prevent exhaustion, as PD-1 induced post-transcriptional c-Jun down-regulation. Remarkably, PD-L1 blockade restored c-Jun levels, dramatically increased CAR-Ts, and enabled near-complete ROR1+ tumor clearance. These findings identify PD-1 as a suppressor of c-Jun and reveal that MHC-independent CAR-Ts can be engineered to establish intratumoral stem-like reservoirs that overcome resistance to PD-1 blockade.
Project description:Biomaterial-based implants encapsulating islets or β-cells are desirable regimens for type 1 diabetes (T1D). However, current implants are restricted by poor durable β-cell survival due to immune cell infiltration, graft fibrosis and hypoxia. Programmed cell death-ligand 1 (PD-L1) induces T cell exhaustion, consequently protecting β-cells from autoimmune attack. Herein, we report an implant encapsulating PD-L1-overexpressing-β-cell microspheres (PD-L1 β-MCSs) and Chlorella within alginate hydrogel to control hyperglycemia in T1D. Virtually, PD-L1-β-cell derived exosomes efficaciously induce T cell exhaustion and convert macrophages into M2 phenotype in vitro. And PD-L1 β-MCSs secrete insulin in response to changes in glucose concentration. Furthermore, PD-L1-β-cell microspheres artificial Pancreas (PD-L1-β-MCSs aPancreas) prominently relieve hyperglycemia with less CD4+ T cells, CD8+ T cells, and M1 macrophages infiltration, inflammation and fibrosis deposition. Intriguingly, Chlorella produces oxygen to relieve hypoxia and enables the PD-L1-β-MCSs aPancreas-transplanted mice to achieve sustained normoglycemia, which potentially benefit from both oxygen supplementation and exosomal PD-L1.
Project description:GPC2 and GD2 are validated CAR T cell targets in neuroblastoma, but durable responses remain limited. We profiled the surfaceome of neuroblastoma-derived extracellular vesicles (EVs) and assessed their impact on CAR T cell function. Neuroblastoma EVs displayed GPC2 and GD2, with minimal PD-L1, and were detected in blood from tumor-bearing mice and patients. These EVs directly activated paired CAR T cells, suggesting a role for a peripheral source of CAR antigen. To exploit this therapeutically, we engineered non-tumor-derived GPC2+ synthetic EVs (SyntEVs) as CAR T cell enhancers and armored them with either albumin- or GD2-binding domains. In mice harboring human neuroblastomas, serial infusion of armored SyntEVs following GPC2 CAR T cells enhanced tumor control by boosting peripheral CAR T cell persistence. Moreover, GD2-targeting SyntEVs decorated low-antigen tumor cells with GPC2, circumventing antigen downregulation. This SyntEV platform offers a versatile system to address the therapeutic limitations of CAR T cells in solid tumors.
Project description:The microtubule-stabilising drug paclitaxel has activity in relapsed ovarian cancer. However, resistance frequently develops. Oncolytic adenoviruses are a novel cancer therapy, and replicate selectively within and lyse malignant cells, leading to productive infection of neighbouring cells. We found increased efficacy of adenoviruses of multiple subtypes in paclitaxel-resistant ovarian cancer cells. There was increased expression of a key adenovirus receptor, CAR (coxsackie adenovirus receptor), due to increased transcription that resulted from histone modification. Moreover, CAR transcription increased in intraperitoneal xenografts with acquired paclitaxel resistance and in tumours from patients with paclitaxel-resistant ovarian cancer. Finally, we identified dysregulated cell cycle control as a second mechanism of increased adenovirus efficacy in paclitaxel-resistant ovarian cancer and that inhibition of CDK4/6 using PD-0332991 was able both to reverse paclitaxel resistance and reduce adenovirus efficacy. Thus, paclitaxel resistance increases oncolytic adenovirus efficacy via at least two separate mechanisms. Parental SKOV3 and paclitaxel-resistant SKOV3-TR cells were analysed in duplicate