Publications by authors named "N Gkitsas"

Article Synopsis
  • Adenosine (Ado) plays a role in suppressing immune responses in tumors, and exhausted CD8 CAR-T cells express enzymes CD39 and CD73 that contribute to Ado production.
  • Researchers attempted to improve CAR-T cell effectiveness by knocking out these enzymes or an adenosine receptor, but saw only minor improvements.
  • However, overexpressing adenosine deaminase (ADA-OE) to convert Ado to inosine (INO) notably enhanced CAR-T cell function, stemness, and metabolic reprogramming, leading to superior CAR-T products suitable for clinical use.
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Background: Chimeric Antigen Receptor (CAR) T cells are now standard of care (SOC) for some patients with B cell and plasma cell malignancies and could disrupt the therapeutic landscape of solid tumors. However, access to CAR-T cells is not adequate to meet clinical needs, in part due to high cost and long lead times for manufacturing clinical grade virus. Non-viral site directed CAR integration can be accomplished using CRISPR/Cas9 and double-stranded DNA (dsDNA) or single-stranded DNA (ssDNA) via homology-directed repair (HDR), however yields with this approach have been limiting for clinical application (dsDNA) or access to large yields sufficient to meet the manufacturing demands outside early phase clinical trials is limited (ssDNA).

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Adenosine (Ado) mediates immune suppression in the tumor microenvironment and exhausted CD8 CAR T cells mediate Ado-induced immunosuppression through CD39/73-dependent Ado production. Knockout of CD39, CD73 or A2aR had modest effects on exhausted CAR T cells, whereas overexpression of Ado deaminase (ADA), which metabolizes Ado to inosine (INO), induced stemness features and potently enhanced functionality. Similarly, and to a greater extent, exposure of CAR T cells to INO augmented CAR T cell function and induced hallmark features of T cell stemness.

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Chimeric antigen receptor (CAR) T cell therapy has made significant strides in the treatment of B-cell malignancies, but its application in treating solid tumors still poses significant challenges. Particularly, the widespread use of viral vectors to deliver CAR transgenes into T cells comes with limitations, including high costs and regulatory restrictions, which hinder the translation of novel genetic engineering concepts into clinical applications. Non-viral methods, such as transposon/transposase and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas systems, offer promising alternatives for stable transgene insertion in CAR-T cells.

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Background: Chimeric antigen receptor (CAR) or T-cell receptor (TCR) engineered T-cell therapy has recently emerged as a promising adoptive immunotherapy approach for the treatment of hematologic malignancies and solid tumors. Multiparametric flow cytometry-based assays play a critical role in monitoring cellular manufacturing steps. Since manufacturing CAR/TCR T-cell products must be in compliance with current good manufacturing practices (cGMP), a standard or quality control for flow cytometry assays should be used to ensure the accuracy of flow cytometry results, but none is currently commercially available.

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