Dasari, Surendra

Abstract BCMA-directed CAR T-cell and T-cell engager (TCE) therapies produce high response rates in relapsed multiple myeloma, yet most patients progress. Prior work identified TNFRSF17 alterations mediating antigen escape in up to 43% of TCE progressions. To evaluate the generalizability of these findings and examine antigen-loss-independent resistance, we performed whole-exome sequencing on 32 paired pre- and post-treatment progression bone marrow samples from 15 patients (5 CAR T, 10 TCE); two patients received both agents. TNFRSF17 alterations were infrequent and restricted to TCE recipients (one concurrent frameshift and missense mutation; two heterozygous copy-number losses); no biallelic loss or CAR T-associated events were observed. In contrast, deleterious/loss-of-function variants in NF-κB, PI3K-AKT-mTOR, and MAPK/ERK pathways were universal in pre-treatment samples and acquired or clonally enriched in 80% of patients at progression. Acquired events included loss-of-function alterations in CYLD , activating mutations in KRAS , NRAS and BRAF , and acquired TP53 mutations. In this series, antigen escape via TNFRSF17 /BCMA alteration was uncommon. Instead, pre-existing, acquired and clonally enriched pathogenic variants in NF-κB, PI3K-AKT-mTOR and MAPK cascades, together with TP53 mutation, emerged as a frequent finding. These alterations suggest that deregulation of BCMA-downstream survival signaling, enhanced proliferative fitness, and elevation of apoptotic threshold constitute antigen-loss-independent mechanisms of resistance.

Abstract Germinal center (GC)-derived lymphomas arise within a specialized immune ecosystem, yet whether malignant cells direct its remodeling remains unclear. Integrating genomic, transcriptomic, spatial, and functional analyses across follicular lymphoma and diffuse large B-cell lymphoma, we define a developmental framework linking malignant B-cell differentiation state to tumor microenvironment (TME) organization. Rather than segregating by histology, lymphomas align along a shared differentiation continuum in which proliferative dark zone (DZ) states associate with immune-depleted TMEs, whereas post-GC/memory B-cell (MBC) states drive inflamed but immunosuppressed TMEs. Spatial profiling reveals collapse of GC architecture and emergence of suppressive myeloid niches along this trajectory. Single-cell lineage reconstruction uncovers a DZ-to-MBC developmental axis underlying lymphoma evolution. Genetic reprogramming in vivo demonstrates that malignant differentiation state is sufficient to instruct TME remodeling. Collectively, these findings establish malignant differentiation state as a causal determinant of immune architecture across GC-derived lymphomas and identify lineage-directed immune reprogramming as a potential therapeutic strategy.

Abstract Taxanes are frontline chemotherapeutics that stabilize microtubules, induce mitotic arrest, and drive tumor remission. However, their off-target effects in healthy tissues, most notably cutaneous axon degeneration underlying chemotherapy-induced peripheral neuropathy (CIPN), remain poorly understood. Here, we show that paclitaxel induces microtubule fasciculation in epidermal keratinocytes through the mitotic kinesin Eg5, thereby initiating CIPN. Mechanistically, paclitaxel enhances Eg5-dependent fasciculation of detyrosinated (stabilized) microtubules, which constrict and breach the nuclear lamina. This deformation triggers tension-dependent NADPH oxidase-mediated nuclear ROS (X-ROS) formation upstream of mmp13 transcription, a pathway we previously demonstrated drives sensory axon degeneration. Employing a cross-species framework spanning zebrafish, mice, human skin biopsies, and a breast adenocarcinoma cell line, we uncover a conserved paclitaxel–Eg5 mechanism leading to fasciculation of stable microtubules in both healthy epidermis and cancer cells. These findings highlight the dualistic nature of paclitaxel action and underscore the challenge of preserving anticancer efficacy while preventing neurotoxic side effects.

Abstract In this retrospective study, BRAF mutation status did not correlate with disease extent or (event-free) survival in 156 adults with Langerhans cell histiocytosis. BRAFV600E was associated with an increased incidence of second malignancies, often comprising hematological cancers, which may be clonally related.

Abstract Purpose: IgM monoclonal gammopathy of undetermined significance (MGUS) and Waldenström macroglobulinemia (WM) represent a disease spectrum with highly varied therapeutic management, ranging from observation to chemoimmunotherapy. The current classification relies solely on clinical features and does not explain the heterogeneity that exists within each of these conditions. Further investigation is warranted to shed light on the biology that may account for the clinical differences. Experimental Design: We used bone marrow (BM) clonal CD19+ and/or CD138+ sorted cells, matched BM supernatant, and peripheral blood serum from 32 patients (7 MGUS, 25 WM) to perform the first multi-omics approach including whole-exome sequencing, RNA sequencing, proteomics, metabolomics, and mass cytometry. Results: We identified three clusters with distinct pathway activation, immune content, metabolomic, and clinical features. Cluster 1 included only patients with WM and was characterized by transcriptional silencing of genes involved in cell cycle and immune response, enrichment of mitochondrial metabolism, infiltration of senescent T effector memory cells, and aggressive clinical behavior. Genetic/structural alterations of TNFAIP3 were distinct events of this cluster. Cluster 2 comprised both MGUS and WM patients with upregulation of inflammatory response, senescence and glycolysis signatures, increased activated T follicular helper and T regulatory cells, and indolent clinical behavior. Cluster 3 also included both MGUS and WM patients and exhibited intermediate features, including proliferative and inflammatory signaling, as well as glycolysis and mitochondrial metabolism. Conclusions: We have identified three distinct molecular clusters, suggesting a potential biologic classification that may have therapeutic implications.

As part of the Multiple Myeloma Research Foundation (MMRF) immune atlas pilot project, we compared immune cells of multiple myeloma bone marrow samples from 18 patients assessed by single-cell RNA sequencing (scRNA-seq), mass cytometry (CyTOF), and cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) to understand the concordance of measurements among single-cell techniques. Cell type abundances are relatively consistent across the three approaches, while variations are observed in T cells, macrophages, and monocytes. Concordance and correlation analysis of cell type marker gene expression across different modalities highlighted the importance of choosing cell type marker genes best suited to particular modalities. By integrating data from these three assays, we found International Staging System stage 3 patients exhibited decreased CD4+ T/CD8+ T cells ratio. Moreover, we observed upregulation of RAC2 and PSMB9, in natural killer cells of fast progressors compared with those of nonprogressors, as revealed by both scRNA-seq and CITE-seq RNA measurement. This detailed examination of the immune microenvironment in multiple myeloma using multiple single-cell technologies revealed markers associated with multiple myeloma rapid progression which will be further characterized by the full-scale immune atlas project. Significance: scRNA-seq, CyTOF, and CITE-seq are increasingly used for evaluating cellular heterogeneity. Understanding their concordances is of great interest. To date, this study is the most comprehensive examination of the measurement of the immune microenvironment in multiple myeloma using the three techniques. Moreover, we identified markers predicted to be significantly associated with multiple myeloma rapid progression.