Biology subjects

Zadro, A.

Publications and source records attributed to Zadro, A..

4 recordsLinked to original sources

bioRxiv2025

Targeting Aberrant FGFR Signaling with Infigratinib Enhances the Efficacy of BTK/PI3K Inhibitors and Bendamustine in Lymphoma Cells

BackgroundAberrant fibroblast growth factor receptor (FGFR) signaling sustains survival and drug tolerance in various cancers, including B-cell lymphomas. We profiled FGFR/FGF expression and evaluated the FGFR1-3 inhibitor infigratinib, both alone and in combination with standard agents, in models of mantle cell lymphoma (MCL), marginal zone lymphoma (MZL), and diffuse large B-cell lymphoma (DLBCL). MethodsTwenty-eight cell lines (MCL n=10; MZL n=7, including BTK/PI3K inhibitor-resistant derivatives; ABC-DLBCL n=3; GCB-DLBCL n=8) were tested by 72-h MTT assays for single-agent and fixed-ratio combination activity. Transcriptome profiling (4, 8, 12 h) was performed in MZL Karpas1718 cells treated with infigratinib (500 nM), ibrutinib (10 nM), or the combination. ResultsMCL preferentially expressed FGFR3/FGF9, whereas ABC-DLBCL and MZL expressed FGFR1/FGF2; FGFR1 was further enriched in resistant MZL models, consistent with autocrine activation. Infigratinib showed dose-dependent but modest single-agent activity across the panel (median IC50 3.58 M, indicating limited efficacy at clinically achievable exposures ([≤]500 nM). However, combinations were broadly synergistic: in MCL, infigratinib with ibrutinib (4/4 lines) and bendamustine (5/5) outperformed either agent alone, with weaker effects with rituximab (2/4). In MZL (parental and resistant), infigratinib synergized with ibrutinib (6/6), copanlisib (6/6), and idelalisib (4/6), restoring sensitivity in resistant derivatives; synergy occurred at infigratinib concentrations [≤]500 nM. Mechanistically, RNA-seq revealed largely distinct single-agent programs: ibrutinib suppressed BCR/NF-{kappa}B/inflammatory signaling, while infigratinib preferentially repressed E2F/MYC cell-cycle modules. In contrast, the combination concomitantly downregulated NF-{kappa}B pathways and abrogated MYC target signatures, with coordinated modulation of apoptosis and DNA-repair transcripts. ConclusionsFGFR1/3-driven autocrine signaling contributes to adaptive survival in MCL and MZL. Although infigratinib has limited single-agent activity, it potentiates BTK/PI3K inhibitors and bendamustine at clinically relevant concentrations and reverses acquired resistance, supporting biomarker-guided clinical evaluation of FGFR blockade in relapsed/refractory MCL and MZL.

cancer biology↗

bioRxiv2025

High-Throughput Screening Identifies PLK1 Inhibition as a Strategy to Potentiate BTK Blockade in Marginal Zone Lymphoma

B-cell receptor (BCR) signaling is a key therapeutic target in B-cell lymphomas, and Bruton tyrosine kinase inhibitors (BTKi) have demonstrated clinical efficacy in marginal zone lymphoma (MZL). However, the rate of complete remissions is relatively low, and resistance remains a significant clinical challenge, underscoring the need for novel combination strategies. To identify compounds that enhance the activity of BTKi and overcome resistance, we conducted a high-throughput screen of 1,695 compounds using a previously developed MZL model of acquired resistance to BTK and PI3K inhibitors derived from the Karpas1718 cell line. Thirty-three compounds showed single-agent anti-proliferative activity in the nanomolar range, both in the Karpas1718-resistant and parental cells. Based on their clinical potential in combination with BTKi, seven compounds were selected for further validation. The polo-like kinase 1 (PLK1) inhibitor rigosertib emerged as a top candidate, showing strong activity in both parental and BTKi-resistant cell lines. Combination treatment of rigosertib and BTKi zanubrutinib resulted in broad transcriptomic changes, characterized by the downregulation of pathways involved in B-cell activation, proliferation, and BCR signaling. Mechanistically, the combination reduced phosphorylation of key BCR pathway components and inhibited NF-{kappa}B nuclear translocation. These findings suggest that PLK1 inhibition can overcome BTKi resistance by further inhibiting BCR signaling through the canonical NF-{kappa}B pathway. Therefore, the dual pharmacological inhibition of BTK and PLK1 is a promising therapeutic approach for patients with MZL and warrants further preclinical and clinical investigations.

cancer biology↗

bioRxiv2025

A High-Throughput Bone Marrow 3D Co-Culture System to Develop Resistance to B Cell Receptor Signaling Targeted Agents in B Cell Non-Hodgkin Lymphoma

B cell receptor (BCR) signaling plays a central role in the pathogenesis of B cell lymphomas, making it a crucial therapeutic target. The advent of BCR-targeted inhibitors, particularly those directed at PI3K and BTK, has revolutionized treatment for B cell non-Hodgkin lymphoma (B-NHL). However, therapeutic resistance remains a significant clinical challenge. Increasing evidence suggests that the tumor microenvironment (TME), particularly the bone marrow (BM) microenvironment, is crucial in driving cancer progression and therapeutic resistance. The BM microenvironment provides a specialized niche where lymphoma cells can evade therapy through interactions with stromal cells and extracellular matrix (ECM) components. Bone marrow stromal cells (BMSCs) contribute significantly to this resistance. In this study, we developed an in vitro 3D model to better understand B cell lymphoma biology and drug resistance mechanisms. We co-cultured lymphoma cell lines with primary BMSCs in a 3D fibrin gel matrix using a high-throughput and automated system. Our results revealed that BMSCs modulate lymphoma cell growth and reduce their sensitivity to the PI3K inhibitor copanlisib and the BTK inhibitor ibrutinib. Furthermore, this model allowed us to identify IGFBP-3, Serpin E1, and PTX-3 as potential mediators of therapeutic resistance. These findings underscore the value of using 3D co-culture models in preclinical settings to more accurately study drug resistance, as they more closely simulate the BM microenvironments complexity than traditional 2D models, thus improving the predictive value of drug testing in B cell lymphomas. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=142 SRC="FIGDIR/small/632958v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@72bc6aorg.highwire.dtl.DTLVardef@afdda2org.highwire.dtl.DTLVardef@1fff494org.highwire.dtl.DTLVardef@11252cf_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOVisual AbstractC_FLOATNO C_FIG

cancer biology↗

bioRxiv2024

Enhancer lncRNA LOC730338 limits the innate immune response against lymphoma cells, inhibiting ADAR2-dependent alternative transcription.

Chronic antigenic stimulation is a central factor in the development of marginal zone lymphoma (MZL). While the pharmacological inhibition of the B-cell receptor (BCR) signaling by Brutons tyrosine kinase (BTK) inhibitors is initially effective, the development of resistance remains a challenge in treating MZL and other B-cell malignancies. Enhancer activation remodeling is a key epigenetic mechanism that enables tumor adaptation during therapy. The most active regulatory regions cluster in super-enhancers and produce enhancer RNAs (eRNAs), a class of unstable noncoding transcripts that primarily serve as scaffolds for chromatin looping. However, when stabilized, these eRNAs can evolve into long noncoding RNA (lncRNAs) with distinct functions. To investigate enhancer-associated long non-coding RNAs (elncRNAs) involved in shaping BCR pathway dependence, we conducted a CRISPR interference (CRISPRi) screen in MZL cells. We identified LOC730338, an elncRNA linked to A-to-I RNA editing, which we renamed ADARreg. ADARreg renders tumor cells refractory to BCR pathway inhibition by modulating ADAR2 nuclear translocation and altering RNA modification patterns in key regulatory isoforms through coordinated control of RNA stability and localization, as revealed through subcellular direct RNA sequencing (DRS). In addition, ADARreg induces an immune-suppressive transcriptional program, increasing the production of inhibitory cytokines and receptors that diminish NK cell-mediated cytotoxicity. Together, these findings uncover a novel role for elncRNAs in orchestrating immune evasion and provide a potential therapeutic strategy to overcome resistance in lymphoma and other immune-related diseases. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=116 SRC="FIGDIR/small/627805v2_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@1c3fa92org.highwire.dtl.DTLVardef@177b234org.highwire.dtl.DTLVardef@154a8fdorg.highwire.dtl.DTLVardef@122acfd_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIThe enhancer-associated long non-coding RNA ADARreg modulates RNA editing and alters the stability and localization of key immune-related transcripts, thereby enabling tumor immune evasion. C_LIO_LIADARreg has prognostic and therapeutic relevance, linking resistance mechanisms and immune modulation, which supports the development of RNA-based therapeutic strategies in cancer. C_LI

cancer biology↗