Establishment of ganglioside GD2-expressing extranodal NK/T-cell lymphoma cell line with scRNA-seq analysis.

Extranodal natural killer (NK)/T-cell lymphoma, nasal type (ENKL), is characterized by Epstein-Barr virus infection and poor prognosis. We established a novel cell line, ENKL-J1, from bone marrow cells of an ENKL patient. We found that ENKL-J1 cells express the ganglioside GD2 (GD2) and that GD2-directed chimeric antigen receptor T cells exhibit cytotoxicity against ENKL-J1 cells, indicating that GD2 would be a suitable target of GD2-expressing ENKL cells. Targeted next-generation sequencing revealed TP53 and TET2 variants in ENKL-J1 cells. Furthermore, single-cell RNA sequencing in ENKL-J1 cells showed high gene-expression levels in the oncogenic signaling pathways JAK-STAT, NF-κB, and MAPK. Genes related to multidrug resistance (ABCC1), tumor suppression (ATG5, CRYBG1, FOXO3, TP53, MGA), anti-apoptosis (BCL2, BCL2L1), immune checkpoints (CD274, CD47), and epigenetic regulation (DDX3X, EZH2, HDAC2/3) also were expressed at high levels. The molecular targeting agents eprenetapopt, tazemetostat, and vorinostat efficiently induced apoptosis in ENKL-J1 cells in vitro. Furthermore, GD2-directed chimeric antigen receptor T cells showed cytotoxicity against ENKL-J1 cells in vivo. These findings not only contribute to understanding the molecular and genomic characteristics of ENKL; they also suggest new treatment options for patients with advanced or relapsed ENKL.

iPSC-derived hypoimmunogenic tissue resident memory T cells mediate robust anti-tumor activity against cervical cancer.

Functionally rejuvenated human papilloma virus-specific cytotoxic T lymphocytes (HPV-rejTs) generated from induced pluripotent stem cells robustly suppress cervical cancer. However, autologous rejT generation is time consuming, leading to difficulty in treating patients with advanced cancer. Although use of allogeneic HPV-rejTs can obviate this, the major obstacle is rejection by the patient immune system. To overcome this, we develop HLA-A24&-E dual integrated HPV-rejTs after erasing HLA class I antigens. These rejTs effectively suppress recipient immune rejection while maintaining more robust cytotoxicity than original cytotoxic T lymphocytes. Single-cell RNA sequencing performed to gain deeper insights reveal that HPV-rejTs are highly enriched with tissue resident memory T cells, which enhance cytotoxicity against cervical cancer through TGFßR signaling, with increased CD103 expression. Genes associated with the immunological synapse also are upregulated, suggesting that these features promote stronger activation of T cell receptor (TCR) and increased TCR-mediated target cell death. We believe that our work will contribute to feasible "off-the-shelf" T cell therapy with robust anti-cervical cancer effects.

Dual-antigen targeted iPSC-derived chimeric antigen receptor-T cell therapy for refractory lymphoma.

We generated dual-antigen receptor (DR) T cells from induced pluripotent stem cells (iPSCs) to mitigate tumor antigen escape. These cells were engineered to express a chimeric antigen receptor (CAR) for the antigen cell surface latent membrane protein 1 (LMP1; LMP1-CAR) and a T cell receptor directed to cell surface latent membrane protein 2 (LMP2), in association with human leucocyte antigen A24, to treat therapy-refractory Epstein-Barr virus-associated lymphomas. We introduced LMP1-CAR into iPSCs derived from LMP2-specific cytotoxic T lymphocytes (CTLs) to generate rejuvenated CTLs (rejTs) active against LMP1 and LMP2, or DRrejTs. All DRrejT-treated mice survived >100 days. Furthermore, DRrejTs rejected follow-up inocula of lymphoma cells, demonstrating that DRrejTs persisted long-term. We also demonstrated that DRrejTs targeting CD19 and LMP2 antigens exhibited a robust tumor suppressive effect and conferred a clear survival advantage. Co-operative antitumor effect and in vivo persistence, with unlimited availability of DRrejT therapy, will provide powerful and sustainable T cell immunotherapy.

iPSC-Derived Neoantigen-Specific CTL Therapy for Ewing Sarcoma.

The prognosis of Ewing sarcoma caused by EWS/FLI1 fusion is poor, especially after metastasis. Although therapy with CTLs targeted against altered EWS/FLI1 sequences at the gene break/fusion site may be effective, CTLs generated from peripheral blood are often exhausted because of continuous exposure to tumor antigens. We addressed this by generating induced pluripotent stem cell (iPSC)-derived functionally rejuvenated CTLs (rejT) directed against the neoantigen encoded by the EWS/FLI1 fusion gene. In this study, we examined the antitumor effects of EWS/FLI1-rejTs against Ewing sarcoma. The altered amino acid sequence at the break/fusion point of EWS/FLI1, when presented as a neoantigen, evokes an immune response that targets EWS/FLI1 + sarcoma. Although the frequency of generated EWS/FLI1-specific CTLs was only 0.003%, we successfully established CTL clones from a healthy donor. We established iPSCs from a EWS/FLI1-specific CTL clone and redifferentiated them into EWS/FLI1-specific rejTs. To evaluate cytotoxicity, we cocultured EWS/FLI1-rejTs with Ewing sarcoma cell lines. EWS/FLI1-rejTs rapidly and continuously suppressed the proliferation of Ewing sarcoma for >40 hours. Using a Ewing sarcoma xenograft mouse model, we verified the antitumor effect of EWS/FLI1-rejTs via imaging, and EWS/FLI1-rejTs conferred a statistically significant survival advantage. "Off-the-shelf" therapy is less destructive and disruptive than chemotherapy, and radiation is always desirable, particularly in adolescents, whom Ewing sarcoma most often affects. Thus, EWS/FLI1-rejTs targeting a Ewing sarcoma neoantigen could be a promising new therapeutic tool.

Sustainable Tumor-Suppressive Effect of iPSC-Derived Rejuvenated T Cells Targeting Cervical Cancers.

Immunotherapy utilizing induced pluripotent stem cell (iPSC) technology has great potential. Functionally rejuvenated cytotoxic T lymphocytes (CTLs) can survive long-term as young memory T cells in vivo, with continuous tumor eradication. Banking of iPSCs as an unlimited "off-the-shelf" source of therapeutic T cells may be feasible. To generate safer iPSCs, we reprogrammed human papilloma virus type 16 (HPV16) E6-specific CTLs by Sendai virus vector without cotransduction of SV40 large T antigen. The iPSCs efficiently differentiated into HPV16-specific rejuvenated CTLs that demonstrated robust cytotoxicity against cervical cancer. The tumor-suppressive effect of rejuvenated CTLs was stronger and more persistent than that of original peripheral blood CTLs. These rejuvenated HPV16-specific CTLs provide a sustained tumor-suppressive effect even for epithelial cancers and constitute promising immunotherapy for cervical cancer.

Dasatinib-induced anti-leukemia cellular immunity through a novel subset of CD57 positive helper/cytotoxic CD4 T cells in chronic myelogenous leukemia patients.

Dasatinib induces lymphocytosis of large granular lymphocytes (LGLs) in a proportion of patients with chronic myelogenous leukemia (CML), and is associated with better clinical outcomes. LGLs consist of cytotoxic T lymphocytes and natural killer cells; however, the context and phenotypic/functional features of each type of LGL are unknown. To better define features of these LGLs, we investigated lymphocytosis in CML patients treated with dasatinib. D57-positive and CD4-positive type I T-helper (Th) cells (CD57+ Th cells) rarely occur in CML patients without lymphocytosis and in healthy individuals; however, a substantial increase in the proportion of CD57+ Th cells was observed in CML patients treated with dasatinib. In addition, these cells showed appreciable levels of cytocidal activity via cytotoxic degranulation. Analysis of T-cell receptor α and ß sequences showed a skewed T-cell repertoire in the CD57+ Th cells. Furthermore, patients with LGLs and CD57+ Th lymphocytosis achieved stronger molecular responses than did those without lymphocytosis. While further studies are warranted, our observations suggest that dasatinib induces the expansion of CD57+ Th-LGLs, which may play a crucial role in the dasatinib-induced response against Philadelphia chromosome-positive leukemia.