Development and optimization of a combinatorial CAR-T cell therapy for AML to overcome on target - off tumor responses

• Autores: Lydia Hörndler Gil
• Directores de la Tesis: Hisse Martien van Santen (dir. tes.)
• Lectura: En la Universidad Autónoma de Madrid ( España ) en 2024
• Idioma: inglés
• Número de páginas: 137
• Títulos paralelos:
  • Desarrollo y optimización de una terapia celular CAR-T combinatoria para la AML para superar las respuestas en el objetivo fuera del tumor
• Enlaces
  • Tesis en acceso abierto en: Biblos-e Archivo
• Resumen

  • Chimeric Antigen Receptor (CAR)-T cell therapy provides important clinical benefits in the treatment of various types of B cell lymphoma, leukemia and multiple myeloma, but successful implementation in the treatment of other types of cancer has yet to be achieved. Amongst the current limitations that stall wider use of CAR-T cell therapy is the difficulty in defining truly tumor-specific CAR-T cell targets. Currently approved CAR-T cell therapies are directed against tumor-associated targets, antigens that are expressed by a sizeable fraction of tumors of a given type but also by non-cancerous cells of the patients. This sharing of antigens gives rise to “on target – off tumor” responses that can have potentially severe side effects that can prohibit the use of this therapy.

    In the context of Acute Myeloid Leukemia (AML), a cancer that upon relapse has few efficacious treatment options and an unfavorable prognosis, the most explored tumor-associated CAR-T cell targets are CD33 and CD123. These proteins are also expressed by myeloid precursors and application of CAR-T cell therapies targeted only at these antigens can give rise to long term myelosuppression, limiting dose and/or duration of the treatment and thus its efficacy. The aim of this study is to explore a combinatorial approach for CAR-T cell therapy against AML, combining a new anti-CD33 CAR with an inhibitory Killer Cell Immunoglobulin-like Receptor (KIR) of the KIR2DL family that can discriminate between two mutually exclusive groups of HLA-C alleles. When patients undergo a bone marrow transplant, haploidentical donor - patient combinations allows selective expression of inhibiting HLA-C alleles on donor-derived myeloid precursors, allowing protection from attack by CD33 CAR-T cells.

    The first part of this thesis describes the successful generation of new, CD33-specific CARs and the selection, by means of in vitro and in vivo T cell activation and cytotoxicity assays, of the variant with the best functional profile. The second part provides evidence, obtained from in vitro T cell activation and cytotoxicity assays and a preclinical model of CD33-directed CAR-T cell immunotherapy, that the inhibitory KIR2DL can block CAR-T cell cytotoxic responses against myeloid leukemic cell lines in function of the HLA-C alleles expressed by these cell lines. It is also shown that this same HLA-C allele-dependent control mechanism is operative in the response of patient-derived, CAR+KIR-transduced T cells against their own AML blasts. Together, these data provide proof of concept of the feasibility to control CD33 CAR-T cell responses by means of an inhibitory KIR and delineate strategies to generate CAR-T cell therapies that selectively kill AML blasts