Biology subjects

Rahnama, R.

Publications and source records attributed to Rahnama, R..

3 recordsLinked to original sources

bioRxiv2026

Deep Learning-based Modeling Enhances Efficacy of Natural Ligand CAR Binders Targeting CD70

CD70 is well-recognized as a promising "pan-cancer: chimeric antigen receptor (CAR) T-cell target. Prior work has shown that a "natural ligand" (NL)-based CAR targeting CD70, employing its physiological interaction partner CD27, may have therapeutic advantages over antibody-based CARs. Yet while antibody-based CARs are routinely optimized by affinity maturation of their scFv, whether the binding sequence of an NL CAR can be engineered to improve its function remains unexplored. Here, we combined deep learning with physics-based modeling to redesign residues at the CD27:CD70 interface, identifying a CD27 variant, "N88A", which enhances the efficacy of CD70-targeting CAR T-cells across models of acute myeloid leukemia, multiple myeloma, and renal cell carcinoma. Biophysical approaches, including molecular dynamics simulations, support a mechanism of increased binder conformational freedom underlying potency enhancement. Our work presents CD27N88A CAR T-cells as a promising new therapeutic option and proposes that computational modeling could be applied to enhance efficacy of other NL-based immunotherapies.

cancer biology↗

bioRxiv2026

B7-H3-targeted natural killer cells effectively kill atypical teratoid / rhabdoid tumors and extend survival in orthotopic xenografts

BackgroundAtypical teratoid/rhabdoid tumors (AT/RTs) are the most common malignant CNS tumor in infants, and patients suffer from low survival rates and treatment-related morbidities. These tumors frequently overexpress the pan-cancer antigen B7-H3 (CD276), which can be targeted with immunotherapy. We hypothesized that adding a B7-H3-targeting cytotoxic chimeric antigen receptor (CAR) to NK cells can enhance killing against AT/RTs. MethodsWe designed a library of variable affinity B7-H3-targeted CARs, which were transduced into primary healthy donor-derived NK cells. We verified B7-H3 expression in a panel of AT/RT cell lines and further engineered luciferase and nuclear GFP-expressing AT/RT (CHLA-04, CHLA-06, BT12, BT37) as well as a CHLA-06-derived B7-H3 knockout. We tested CAR-NK cell functionality using in vitro co-culture cytotoxicity assays. We delivered anti-B7-H3 CAR-NK cells intratumorally or intracerebroventricularly (ICV) to AT/RT orthotopic xenografts and monitored for tumor growth and animal survival. ResultsB7-H3-targeted CAR-NK cells demonstrated target-specific cytotoxicity when compared to unmodified NK cells. Knockout of B7-H3 in target cells abolished the increased CAR-mediated target killing. When delivered intratumorally to CHLA-06 orthotopic xenograft-bearing mice, anti-B7-H3 CAR-NK cells eliminated tumor cells and prolonged survival. When CAR-NK cells were delivered ICV against a CNS disseminated tumor model of BT12, treated mice had significantly improved survival. ConclusionsAnti-B7-H3 CAR-NK cells effectively kill AT/RTs in multiple pre-clinical in vitro and in vivo models in an antigen-specific manner. Evidence of efficacy in translationally relevant models provides support for using B7-H3-targeting CAR-NK cells in high-risk AT/RT patients.

cancer biology↗

bioRxiv2021

Engineering CAR-NK cells to secrete IL15 sustains their anti-AML functionality, but is associated with systemic toxicities

BackgroundThe prognosis of patients with recurrent/refractory acute myelogenous leukemia (AML) remains poor and cell-based immunotherapies hold promise to improve outcomes. NK cells can elicit an anti-leukemic response via a repertoire of activating receptors that bind AML surface ligands. NK cell adoptive transfer is safe but thus far has shown limited anti-AML efficacy. Here, we aimed to overcome this limitation by engineering NK cells to express chimeric antigen receptors (CARs) to boost their anti-AML activity, and interleukin-15 (IL15) to enhance their persistence. MethodsWe characterized in detail NK cell populations expressing a panel of AML (CD123)-specific CARs and/or IL15 in vitro and in AML xenograft models. ResultsCARs with 2B4.{zeta} or 4-1BB.{zeta} signaling domains demonstrated greater cell surface expression and endowed NK cells with improved anti-AML activity in vitro. Initial in vivo testing revealed that only 2B4.{zeta} CAR-NK cells had improved anti-AML activity in comparison to untransduced (UTD) and 4-1BB.{zeta} CAR-NK cells. However, the benefit was transient due to limited CAR-NK cell persistence. Transgenic expression of secretory (s)IL15 in 2B4.{zeta} CAR and UTD NK cells improved their effector function in the setting of chronic antigen simulation in vitro. Multiparameter flow analysis after chronic antigen exposure identified the expansion of unique NK cell subsets. 2B4.{zeta}/sIL15 CAR and sIL15 NK cells maintained an overall activated NK cell phenotype. This was confirmed by transcriptomic analysis, which revealed a highly proliferative and activated signature in these NK cell groups. In vivo, 2B4.{zeta}/sIL15 CAR-NK cells had potent anti-AML activity in one model, while 2B4.{zeta}/sIL15 CAR and sIL15 NK cells induced lethal toxicity in a second model. ConclusionTransgenic expression of CD123-CARs and sIL15 enabled NK cells to function in the setting of chronic antigen exposure but was associated with systemic toxicities. Thus, our study provides the impetus to explore inducible and controllable expression systems to provide cytokine signals to AML-specific CAR-NK cells before embarking on early phase clinical testing. O_FIG O_LINKSMALLFIG WIDTH=161 HEIGHT=200 SRC="FIGDIR/small/461509v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@4d09eaorg.highwire.dtl.DTLVardef@1c61411org.highwire.dtl.DTLVardef@14f8097org.highwire.dtl.DTLVardef@8375ac_HPS_FORMAT_FIGEXP M_FIG C_FIG In BriefSecretion of IL15 from anti-CD123.2B4.CD3{zeta} CAR-NK cells enhances their activation and killing potential against Acute Myelogenous Leukemia, but carries the risk of severe systemic toxicity.

immunology↗