Abstract PR02: Aging-associated molecular and cellular alterations determine the biology and clinical characteristics of DLBCL in elderly patients
Authors: Zamponi Nahuel , Revuelta Maria Victoria , Marullo Rossella , Di Siervi Nicolas , Kotlov Nikita , Béguelin Wendy , Cerchietti Leandro 
Published: June 2024

Abstract
About 30% of DLBCLs occur in patients over 75 years old. Due to comorbidities, this potentially curable disease is treated with a reduced dose chemoimmunotherapy regimen, associated with worse response rates and outcomes than the standard approach. Our data indicates that even those able to tolerate full-dose treatments have comparatively worse outcomes. We found that DLBCLs in older patients are more frequently of the ABC-DLBCL subgroup, and their microenvironment (TME) has infiltration of inflammatory and immunosuppressed cells, both characteristics independently associated with chemoimmunotherapy resistance. These features may imply we are facing different biologically diseases. To investigate this, we developed aged DLBCL murine models by implanting three murine lymphoma cells (harboring Setd2/BCL2, Ezh2/BCL2 and Tp53 mutations) in the spleen of young (3-4 months) and aged (21-23 months) mice and monitoring tumor growth by in vivo imaging. We also performed an integrative characterization of the TME from young and aged mice by single cell RNA-sequencing (coding and BCR/TCR), immunophenotyping (flow cytometry) and (MS)-based proteomics. For these two different murine DLBCL cell lines utilized, aged mice had higher tumor burden and showed significantly worse survival than younger mice. In addition, DLBCL cells isolated from aged mice displayed higher clonality and the activation of pro-inflammatory transcriptional programs than DLBCL cells isolated from younger mice. Regarding non-malignant TME B cells, CD11c+ T-bet+ Zeb2+ age-associated B cells (AABs) were significantly more abundant in aged v young mice. AABs displayed a secretory phenotype and transcriptional up-regulation of genes associated with pro-inflammatory programs such as IL-6, Stat3 and Nfatc1. TME T cells showed profound changes including increased infiltration of Foxp3+ Tregs and Pd1+ Cd8+ T cells, as well as the appearance of Cd8+ Gzk+ aged-associated T cells (ATT). Aged mice presented alterations in the myeloid compartment with expansion of Cd45+ Cd11b+ cells. Moreover, the TME of aged mice was enriched in tumor-associated macrophages polarized towards a pro-inflammatory phenotype as well as more abundance of Ly6C+ Ly6G+ myeloid-derived suppressor cells (MDSC). Aged TMEs were also characterized by increased stiffness and extracellular matrix changes affecting collagen and proteoglycans. These TME changes, were associated with intrinsic signaling and transcriptional changes in lymphoma cells like increased activation of NF-kB pathway. Overall, these alterations were compatible with the TME of elderly DLBCL patients showing a global increase in the proportion of inflammatory and immunosuppressive (IN-LME) category (41% in 75-85 y.o. vs. 26% in 50-65 y.o.) and specifically in Tregs, MDSC and CD8 PD1HIGH cells in 75-85 y.o. This data indicates that low-grade chronic inflammation that has been associated with age-related diseases determines molecular and cellular characteristics of the DLBCL in the elderly population.
Citation Format: Nahuel Zamponi, Maria Victoria Revuelta, Rossella Marullo, Nicolas Di Siervi, Nikita Kotlov, Wendy Béguelin, Leandro Cerchietti. Aging-associated molecular and cellular alterations determine the biology and clinical characteristics of DLBCL in elderly patients [abstract]. In: Proceedings of the Fourth AACR International Meeting on Advances in Malignant Lymphoma: Maximizing the Basic-Translational Interface for Clinical Application; 2024 Jun 19-22; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(3_Suppl):Abstract nr PR02.