Biology subjects

Rosenkrans, Z. T.

Publications and source records attributed to Rosenkrans, Z. T..

3 recordsLinked to original sources

bioRxiv2024

Bispecific GD2 x B7-H3 Antibody Improves Tumor Targeting and Reduces Toxicity while Maintaining Efficacy for Neuroblastoma

The current treatment for neuroblastoma involves an immunotherapy regimen that includes a monoclonal antibody that recognizes disialoganglioside (GD2), expressed at high levels on neuroblastoma. GD2 is not present on most normal tissues but is expressed on nerves. Thus, anti-GD2 treatment causes substantial, dose-limiting, neuropathic pain. B7-H3 is overexpressed on multiple tumor types, including neuroblastoma, with minimal normal cell expression and is absent on nerves. We designed a bispecific antibody (bsAb) that requires simultaneous binding of these two tumor antigens to achieve tight-binding of tumor cells. Our preclinical research shows that when compared to an anti-GD2 monospecific antibody, the GD2xB7-H3 bsAb has improved tumor specificity with similar efficacy and reduced toxicity. Since this bsAb does not bind to nerves, it may be possible to administer increased or additional doses beyond the tolerable dose of monospecific anti-GD2 antibodies, which could improve therapeutic efficacy and quality of life for patients with neuroblastoma.

cancer biology↗

bioRxiv2024

Targeting both GD2 and B7-H3 using bispecific antibody improves tumor selectivity for GD2-positive tumors

ObjectivesDisialoganglioside 2 (GD2), overexpressed by cancers such as melanoma and neuroblastoma, is a tumor antigen for targeted therapy. The delivery of conventional IgG antibody technologies targeting GD2 is limited clinically by its co-expression on nerves that contributes to toxicity presenting as severe neuropathic pain. To improve the tumor selectivity of current GD2-targeting approaches, a next-generation bispecific antibody targeting GD2 and B7-H3 (CD276) was generated. MethodsDifferential expression of human B7-H3 (hB7-H3) was transduced into GD2+ B78 murine melanoma cells and confirmed by flow cytometry. We assessed the avidity and selectivity of our GD2-B7-H3 targeting bispecific antibodies (INV34-6, INV33-2, and INV36-6) towards GD2+/hB7-H3- B78 cells relative to GD2+/hB7-H3+ B78 cells using flow cytometry and competition binding assays, comparing results an anti-GD2 antibody (dinutuximab, DINU). The bispecific antibodies, DINU, and a non-targeted bispecific control (bsAb CTRL) were conjugated with deferoxamine for radiolabeling with Zr-89 (t1/2 = 78.4 h). Using positron emission tomography (PET) studies, we evaluated the in vivo avidity and selectivity of the GD2-B7-H3 targeting bispecific compared to bsAb CTRL and DINU using GD2+/hB7-H3+ and GD2+/hB7-H3- B78 tumor models. ResultsFlow cytometry and competition binding assays showed that INV34-6 bound with high avidity to GD2+/hB7-H3+ B78 cells with high avidity but not GD2+/hB7-H3+ B78 cells. In comparison, no selectivity between cell types was observed for DINU. PET in mice bearing the GD2+/hB7-H3- and GD2+/hB7-H3+ B78 murine tumor showed similar biodistribution in normal tissues for [89Zr]Zr-Df-INV34-6, [89Zr]Zr-Df-bsAb CTRL, and [89Zr]Zr-Df-DINU. Importantly, [89Zr]Zr-Df-INV34-6 tumor uptake was selective to GD2+/hB7-H3+ B78 over GD2+/hB7-H3- B78 tumors, and substantially higher to GD2+/hB7-H3+ B78 than the non-targeted [89Zr]Zr-Df-bsAb CTRL control. [89Zr]Zr-Df-DINU displayed similar uptake in both GD2+ tumor models, with uptake comparable to [89Zr]Zr-Df-INV34-6 in the GD2+/hB7-H3+ B78 model. ConclusionThe GD2-B7-H3 targeting bispecific antibodies successfully improved selectivity to cells expressing both antigens. This approach should address the severe toxicities associated with GD2-targeting therapies by reducing off-tumor GD2 binding in nerves. Continued improvements in bispecific antibody technologies will continue to transform the therapeutic biologics landscape. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=114 SRC="FIGDIR/small/595624v2_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@11afee9org.highwire.dtl.DTLVardef@1558607org.highwire.dtl.DTLVardef@1d23d6eorg.highwire.dtl.DTLVardef@1bf1d63_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2021

Investigating the in vivo biodistribution of extracellular vesicles isolated from various human cell sources using positron emission tomography

Noninvasive imaging is a powerful tool for understanding the in vivo behavior of drug delivery systems and successfully translating promising platforms into the clinic. Extracellular vesicles (EVs), nano-sized vesicles with a lipid bilayer produced by nearly all cell types, are emerging platforms for drug delivery. To date, the biodistribution of EVs has been insufficiently investigated, particularly using nuclear imaging-based modalities such as positron emission tomography (PET). Herein, we developed positron-emitting radiotracers to investigate the biodistribution of EVs isolated from various human cell sources using PET imaging. Chelator conjugation did not impact EVs size and subsequent radiolabeling was found to be highly efficient and stable with Zr-89 (t1/2 = 78.4 h). In vivo tracking of EVs isolated from bone marrow-derived mesenchymal stromal cells (BMSCs EVs), primary human macrophages (M{phi} EVs), and a melanoma cell line (A375 EVs) were performed in immunocompetent ICR mice. Imaging studies revealed excellent in vivo circulation for all EVs, with a half-life of approximately 12 h. Significantly higher liver uptake was observed for M{phi} EVs, evidencing the tissue tropism of EV and highlighting the importance of carefully choosing EVs cell sources for drug delivery applications. Conversely, the liver, spleen, and lung uptake of the BMSC EVs and A375 EVs was relatively low. We also investigated the impact of immunodeficiency on the biodistribution of BMSC EVs using NSG mice. The spleen uptake drastically increased in NSG mice, which could confound results of therapeutic studies employing this mouse models. Lastly, PET imaging studies in a melanoma tumor model demonstrated efficient tumor uptake of BMSC EVs following intravenous injection. Overall, these imaging studies evidenced the potential of EVs as carriers to treat a variety of diseases, such as cancer or in regenerative medicine applications, and the necessity to understand EVs tropism to optimize their therapeutic deployment.

bioengineering↗