Direct Targeting of CXCR2 Receptor Inhibits Neuroblastoma Growth: An In Vitro Assessment

<b>Background</b>: This study addresses an important vulnerability in the treatment of high-risk neuroblastoma (NB). NB is characterized by high rates of metastasis, drug resistance, relapse, and treatment-related toxicities. Current treatments, which include intensive chemotherapy, surgical removal of tumors, and stem cell transplants, have less than 50 percent survival rates among high-risk NB patients, demonstrating the need for novel targeted treatment approaches. CXC chemokine receptor 2 (CXCR2), a G-protein-coupled receptor, has been implicated in promoting cancer cell proliferation, invasion, metastasis, angiogenesis, chemoresistance, and maintaining cancer stem cells. <b>Methods</b>: We analyzed transcriptomic data from 1464 primary NB patient samples to evaluate the prognostic significance of CXCR2 expression. Pharmacological inhibition of CXCR2 using SB225002, a selective small-molecule antagonist, was evaluated to determine its effects on cell growth, colony formation, apoptosis, and cell cycle progression in different NB cell lines. Three-dimensional (3D) spheroid models were used to examine tumor growth under physiologically relevant conditions. Mechanistic studies included gene expression analyses and immunoblot validation of key signaling regulators. <b>Results</b>: High CXCR2 expression was found to be inversely correlated with overall survival in patient datasets, suggesting a role in NB pathogenesis. Treatment with SB225002 significantly inhibited NB proliferation and colony formation while inducing apoptosis and cell cycle arrest in a dose-dependent manner. In 3D spheroid models, SB225002 significantly impaired spheroid formation and growth, confirming its potent anti-tumor efficacy. Mechanistically, CXCR2 blockade inhibited the expression of key pathway targets, including <i>GLIPR1</i>, <i>BACH2</i>, <i>JUN</i>, <i>CHEK1</i>, <i>AKT1</i>, and <i>CXCR2</i> itself. Immunoblot analysis confirmed significant inhibition of CXCR2 and GLIPR1 protein levels in response to SB225002 treatment. <b>Conclusions</b>: Taken together, our findings demonstrate that pharmacological inhibition of CXCR2 using SB225002 effectively inhibits NB tumor cell growth and tumorigenicity by modulating oncogenic signaling networks. This study provides strong evidence for elucidating CXCR2-targeted therapies as an attractive treatment option for NB. These findings support the development of CXCR2-targeted therapies for high-risk NB.