Although adoptive T-cell therapy has shown remarkable clinical efficacy in haematological malignancies, its success in combating solid tumours has been limited. Here, we report that PTPN2 deletion in T cells enhances cancer immunosurveillance and the efficacy of adoptively transferred tumour-specific T cells. T-cellspecific PTPN2 deficiency prevented tumours forming in aged mice heterozygous for the tumour suppressor p53. Adoptive transfer of PTPN2-deficient CD8 + T cells markedly repressed tumour formation in mice bearing mammary tumours. Moreover, PTPN2 deletion in T cells expressing a chimeric antigen receptor (CAR) specific for the oncoprotein HER-2 increased the activation of the Src family kinase LCK and cytokine-induced STAT-5 signalling, thereby enhancing both CAR T-cell activation and homing to CXCL9/10expressing tumours to eradicate HER-2 + mammary tumours in vivo. Our findings define PTPN2 as a target for bolstering T-cellmediated anti-tumour immunity and CAR T-cell therapy against solid tumours.
Key Points• DIAPH1 (mDia1) is involved in both Rho-mediated actin polymerization and microtubule assembly and stability during proplatelet formation.Megakaryocytes are highly specialized precursor cells that produce platelets via cytoplasmic extensions called proplatelets. Proplatelet formation (PPF) requires profound changes in microtubule and actin organization. In this work, we demonstrated that DIAPH1 (mDia1), a mammalian homolog of Drosophila diaphanous that works as an effector of the small GTPase Rho, negatively regulates PPF by controlling the dynamics of the actin and microtubule cytoskeletons. Moreover, we showed that inhibition of both DIAPH1 and the Rho-associated protein kinase (Rock)/myosin pathway increased PPF via coordination of both cytoskeletons. We provide evidence that 2 major effectors of the Rho GTPase pathway (DIAPH1 and Rock/myosin II) are involved not only in Rho-mediated stress fibers assembly, but also in the regulation of microtubule stability and dynamics during PPF. (Blood. 2014;124(26):3967-3977)
Adenosine is an immunosuppressive factor that limits anti-tumor immunity through the suppression of multiple immune subsets including T cells via activation of the adenosine A2A receptor (A2AR). Using both murine and human chimeric antigen receptor (CAR) T cells, here we show that targeting A2AR with a clinically relevant CRISPR/Cas9 strategy significantly enhances their in vivo efficacy, leading to improved survival of mice. Effects evoked by CRISPR/Cas9 mediated gene deletion of A2AR are superior to shRNA mediated knockdown or pharmacological blockade of A2AR. Mechanistically, human A2AR-edited CAR T cells are significantly resistant to adenosine-mediated transcriptional changes, resulting in enhanced production of cytokines including IFNγ and TNF, and increased expression of JAK-STAT signaling pathway associated genes. A2AR deficient CAR T cells are well tolerated and do not induce overt pathologies in mice, supporting the use of CRISPR/Cas9 to target A2AR for the improvement of CAR T cell function in the clinic.
Although adoptive T‐cell therapy has shown remarkable clinical efficacy in haematological malignancies, its success in combating solid tumours has been limited. Here, we report that PTPN2 deletion in T cells enhances cancer immunosurveillance and the efficacy of adoptively transferred tumour‐specific T cells. T‐cell‐specific PTPN2 deficiency prevented tumours forming in aged mice heterozygous for the tumour suppressor p53. Adoptive transfer of PTPN2‐deficient CD8+ T cells markedly repressed tumour formation in mice bearing mammary tumours. Moreover, PTPN2 deletion in T cells expressing a chimeric antigen receptor (CAR) specific for the oncoprotein HER‐2 increased the activation of the Src family kinase LCK and cytokine‐induced STAT‐5 signalling, thereby enhancing both CAR T‐cell activation and homing to CXCL9/10‐expressing tumours to eradicate HER‐2+ mammary tumours in vivo. Our findings define PTPN2 as a target for bolstering T‐cell‐mediated anti‐tumour immunity and CAR T‐cell therapy against solid tumours.
The Johnstone laboratory receives research support from Roche, BMS, Astra-Zeneca and MecRx. RWJ is a scientific consultant and shareholder in MecRx. The McArthur laboratory receives non-financial support from Pfizer Oncology for supply of palbociclib.Research.
text of cancer, this may mean that tumor-specific T cell clones are sequestered. This has been shown in preclinical studies in melanoma, in which anti-RANKL rescued melanoma-specific T cells and enhanced anti-PD-1 (124). There are several clinical trials testing anti-RANKL plus anti-PD-1 in melanoma and non-small cell lung carcinoma (Supplemental Table 1), but no pediatric trials. This combination could potentially be very effective in pediatric osteosarcoma.Overall, many clinical trials are combining immune checkpoint inhibitors with immunomodulatory agents to improve response in adult cancers, but few trials in children. Once the safety and efficacy of these combinations are established, they will likely be extended to pediatric malignancies. This will result in new treatment combinations for childhood cancers that otherwise would be nonresponsive to immunotherapies, and will meaningfully improve patient outcomes.
Sarcomas are a diverse group of bone and soft tissue tumors that account for over 10% of childhood cancers. Outcomes are particularly poor for children with refractory, relapsed, or metastatic disease. Chimeric antigen receptor T (CAR T) cells are an exciting form of adoptive cell therapy that potentially offers new hope for these children. In early trials, promising outcomes have been achieved in some pediatric patients with sarcoma. However, many children do not derive benefit despite significant expression of the targeted tumor antigen. The success of CAR T cell therapy in sarcomas and other solid tumors is limited by the immunosuppressive tumor microenvironment (TME). In this review, we provide an update of the CAR T cell therapies that are currently being tested in pediatric sarcoma clinical trials, including those targeting tumors that express HER2, NY-ESO, GD2, EGFR, GPC3, B7-H3, and MAGE-A4. We also outline promising new CAR T cells that are in pre-clinical development. Finally, we discuss strategies that are being used to overcome tumor-mediated immunosuppression in solid tumors; these strategies have the potential to improve clinical outcomes of CAR T cell therapy for children with sarcoma.
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