Effectiveness of 4-1BB-costimulated HER2-targeted chimeric antigen receptor T cell therapy for synovial sarcoma

The effects of anti-lung cancer in nude mice by a fully human single-chain antibody against associated antigen Ts7TMR between A549 cells and Trichinella spiralis

Lung cancer is a dangerous disease that is lacking in an ideal therapy. Here, we evaluated the anti-lung cancer effect in nude mice of a fully human single-chain antibody (scFv) against the associated antigen 7 transmembrane receptor (Ts7TMR), which is also called G protein-coupled receptor, between A549 cells and Trichinella spiralis (T. spiralis). Our data showed that anti-Ts7TMR scFv could inhibit lung cancer growth in a dose-dependent manner, with a tumour inhibition rate of 59.1%. HE staining did not reveal any obvious tissue damage. Mechanistically, immunohistochemical staining revealed that the scFv down-regulated the expression of PCNA and VEGF in tumour tissues. Overall, this study found that anti-Ts7TMR scFv could inhibit A549 lung cancer growth by suppressing cell proliferation and angiogenesis, which may provide a new strategy for treating lung cancer.

Current advances and challenges in CAR T-Cell therapy for solid tumors: tumor-associated antigens and the tumor microenvironment

The past decade has witnessed ongoing progress in immune therapy to ameliorate human health. As an emerging technique, chimeric antigen receptor (CAR) T-cell therapy has the advantages of specific killing of cancer cells, a high remission rate of cancer-induced symptoms, rapid tumor eradication, and long-lasting tumor immunity, opening a new window for tumor treatment. However, challenges remain in CAR T-cell therapy for solid tumors due to target diversity, tumor heterogeneity, and the complex microenvironment. In this review, we have outlined the development of the CAR T-cell technique, summarized the current advances in tumor-associated antigens (TAAs), and highlighted the importance of tumor-specific antigens (TSAs) or neoantigens for solid tumors. We also addressed the challenge of the TAA binding domain in CARs to overcome off-tumor toxicity. Moreover, we illustrated the dominant tumor microenvironment (TME)-induced challenges and new strategies based on TME-associated antigens (TMAs) for solid tumor CAR T-cell therapy.

NKp44-based chimeric antigen receptor effectively redirects primary T cells against synovial sarcoma

BACKGROUND

T-cell receptor-engineered T-cell therapies have achieved promising response rates against synovial sarcoma in clinical trials, but their applicability is limited owing to the HLA matching requirement. Chimeric antigen receptor (CAR) can redirect primary T cells to tumor-associated antigens without requiring HLA matching. However, various obstacles, including the paucity of targetable antigens, must be addressed for synovial sarcoma. Ligands for natural killer (NK) cell-activating receptors are highly expressed by tumor cells.

METHODS

The surface expression of ligands for NK cell-activating receptors in synovial sarcoma cell lines was analyzed. We analyzed RNA sequencing data deposited in a public database to evaluate NKp44-ligand expression. Primary T cells retrovirally transduced with CAR targeting NKp44 ligands were evaluated for their functions in synovial sarcoma cells. Alterations induced by various stimuli, including a histone deacetylase inhibitor, a hypomethylating agent, inflammatory cytokines, and ionizing radiation, in the expression levels of NKp44 ligands were investigated.

RESULTS

Ligands for NKp44 and NKp30 were expressed in all cell lines. NKG2D ligands were barely expressed in a single cell line. None of the cell lines expressed NKp46 ligand. Primary synovial sarcoma cells expressed the mRNA of the truncated isoform of MLL5, a known cellular ligand for NKp44. NKp44-based CAR T cells specifically recognize synovial sarcoma cells, secrete interferon-γ, and exert suppressive effects on tumor cell growth. No stimulus altered the expression of NKp44 ligands.

CONCLUSION

NKp44-based CAR T cells can redirect primary human T cells to synovial sarcoma cells. CAR-based cell therapies may be an option for treating synovial sarcomas.