Abstract 1655: Development of humanized diffuse large B-cell lymphoma mouse models
Authors: Mehdi Syed Hassan , Xu Ying-Zhi , Shultz Leonard , Kendrick Samantha , Yoon Donghoon 
Published: June 2022

Abstract
Diffuse Large B-cell Lymphoma (DLBCL) is a commonly diagnosed aggressive non-Hodgkin’s lymphoma, with ~40% of patients experiencing the refractory or relapsed disease. The development of alternative therapies that target molecular features defining these unresponsive tumors is an active area of research to advance the field and improve clinical management significantly. However, few DLBCL animal models exist to test the efficacy of newly developed treatments and are restricted to transgenic or xenograft mice that often fail to recapitulate its sub-classifications. We explored the utility of humanizing Nod-Scid-IL2Rγnull (NSG) strains with human cytokines to establish a pipeline for the rapid, reliable generation of in vivo DLBCL models. We transduced the well-established human DLBCL cells, U2932, with the luciferase (Luc)-EGFP gene, then sorted for GFP positivity. The 1 x 106 U2932-Luc cells were injected via tail-vein into eight 12-week-old mice of various humanized NSG strains (representing equal numbers of each sex). We assessed U2932-Luc cell engraftment and growth weekly in vivo imaging (IVIS 200 Imager). To further evaluate the organ-specific engraftment/progression of U2932-Luc in the mouse, a mouse was sacrificed weekly after 15 minutes of luciferin administration. The organs were extracted and scanned for ex vivo IVIS imaging. The spleen, lung, and liver were then fixed with 10% formalin and embedded in paraffin. Sections were stained with hematoxylin, eosin, and an anti-CD20 antibody to evaluate the tumor infiltration and expansion. Unlike the previously reported DLBCL humanized strain (MISTRG6) (Hashwah et al., 2019), we included the human IL-6 expressing mouse strain. We found that both the IL6 and IL6/SGM3 strains were highly permissive to DLBCL growth. The IL-6 strain exhibited a rapid expansion of U2932 cells relative to the IL-6/SGM3 mice. The IL-6 mice survived longer than IL-6/SGM3 mice. A significant difference between the median survivals of IL-6 and IL-6/SGM3 mice (i.e., 48 vs. 42 days) was observed (p &lt; 0.0482). The organ-specific evaluation demonstrated that U2932-Luc cells were initially engrafted and grew in the lung, liver, and spleen, subsequently found in the skeleton, ovary, and brain. Of note, we detected significant enlargements of the kidney, spleen, and ovary at the terminal stage. Our humanized mouse model approach of using U2932 human DLBCL cells transduced with the Luc gene in the NSG-IL-6 and NSG-IL-6/SGM3 mice reproduced the clinical features of an aggressive DLBCL that paralleled the original patient. This model will provide a new tool to enable the expansion of patient samples while overcoming the current limitations of DLBCL xenografts and transgenic mice. The ability to maintain the growth of patient-derived samples within clinically relevant locations has great potential to more accurately test patient-specific, personalized treatment strategies.
Citation Format: Syed Hassan Mehdi, Ying-Zhi Xu, Leonard Shultz, Samantha Kendrick, Donghoon Yoon. Development of humanized diffuse large B-cell lymphoma mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1655.