Abstract 313: Discovery of novel CXCR4 targeting compounds with antitumor activity in preclinical models of diffuse large B-cell lymphoma

The constitutive activation of CXC motif chemokine receptor 4 (CXCR4) is strongly implicated in tumor progression, metastasis, invasion, and chemotherapy resistance. In diffuse large B-cell lymphoma (DLBCL), the most common subtype of mature B-cell non-Hodgkin lymphoma, CXCR4 activation is associated with poor prognosis. Previous attempts to target CXCR4 in this disease using tetraamine-based inhibitors (CXCR4-i) have been limited by suboptimal pharmacological properties. Using structure-based drug design, we identified novel CXCR4-i candidates with potential anti-lymphoma activity. A library of 31 highly pure compounds was synthesized and evaluated for cytotoxicity in DLBCL cell lines via the MTT assay. Four compounds showed concentration-dependent antiproliferative effects, with 46-59% and 57-96% inhibition at 30 μM and 50 μM, respectively. The most potent compound, IQS-022, achieved up to 96% viability reduction at 50 μM, with an IC50 of 45.5 μM at 24 hours across seven DLBCL cell lines representing the ABC and GCB subtypes. In an immunocompetent chicken chorioallantoic membrane (CAM) DLBCL xenograft model, 50 μM IQS-022 reduced tumor area by 36.5% and decreased tumor B-cell infiltration in the heart and bone marrow by 54.7% and 74.2%, respectively. However, treatment led to >30% embryo weight loss, indicating limited selectivity, as corroborated by off-target effects in human peripheral blood mononuclear cells (PBMCs). To address this limitation, five new tetraamine derivatives were synthesized. Among these, IQS-036 demonstrated similar potency (IC50 = 38.14 μM at 24 hours) but significantly improved selectivity, reducing DLBCL cell viability by 52% at 30 μM while sparing PBMCs (10% viability reduction). Flow cytometry revealed that 94-97% of DLBCL cells underwent apoptosis after 24-hour exposure to 50 μM IQS-036, whereas the standard CXCR4-i, Plerixafor, showed minimal apoptogenic effects. IQS-036 exhibited concentration-dependent CXCR4 occupancy (64% at 20 μM) and decreased sensitivity in CRISPR-engineered NALM6-CXCR4KO cells compared to wild-type counterparts. In vivo, 30 μM IQS-036 inhibited tumor growth by 42% in NALM6-CXCR4WT xenografts without systemic toxicity, whereas CXCR4-knockout tumors were unresponsive. These findings establish CXCR4 as a viable therapeutic target in DLBCL and identify IQS-036 as a potent, selective, and specific CXCR4 inhibitor with significant antitumor activity in lymphoid neoplasms. Citation Format: Miranda Fernandez-Serrano, Nuria Profitos-Peleja, Judith Camalo-Vila, Miquel Martinez-Asensio, Jordi Teixido, Jose I. Borrell, Albert Gibert, Raimon Puig de la Bellacasa, Roger Estrada-Tejedor, Gael Roue. Discovery of novel CXCR4 targeting compounds with antitumor activity in preclinical models of diffuse large B-cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 313.