Formyl peptide receptor 2 activation by MR-39 inhibits glioblastoma cell proliferation and invasiveness through suppression of multiple oncogenic pathways

BACKGROUND: Glioblastoma (GBM) is the most common, aggressive and poor prognosis malignant brain tumor in adults, that is still orphan of effective medical treatments. The formyl peptide receptor 2 (FPR2), a G protein– coupled receptor implicated in inflammation and Cancer biology, has emerged as a potential therapeutic target, yet its role in GBM remains poorly defined. METHODS: We investigated the effects of MR-39, a novel selective FPR2 agonist, in three human GBM cell lines (U87MG, U138-MG, U251-MG). Antiproliferative effects were assessed via CCK-8 assays, cell counts, Ki67 immunostaining, and cell cycle analysis. The specificity of MR-39 was tested using the FPR2 antagonist WRW4 and siRNA-mediated knockdown. Whole-transcriptome analysis, RT-qPCR, Western Blot, woundhealing assays, in vitro tube formation assay, and hypoxia models were used to explore its impact on invasion, angiogenesis, and hypoxia-driven pathways. RESULTS: MR-39 significantly reduced proliferation in all GBM cell lines and induced a non-canonical, p53dependent S-phase arrest associated with the inhibition of both MAPK/ERK and Akt pathways. These effects were reversed by the FPR2 antagonist WRW4 or by FPR2 silencing. Transcriptomic and functional assays revealed downregulation of epithelial-to-mesenchymal transition (EMT) drivers, including Neuralcadherin (N-Cadherin), Snail Family Transcriptional Repressor 2 (Slug), Snail Family Transcriptional Repressor 1 (Snail), matrix metalloproteinase-2 (MMP2), fibronectin 1 (FN1), and increased Epithelialcadherin (E-cadherin) expression, resulting in impaired migration. MR-39 displays anti-angiogenic and anti-hypoxia related activities, indeed it is able to inhibit Vascular Endothelial Growth Factor (VEGF) and Vascular Endothelial-cadherin (VE-cadherin) expression, to disrupt endothelial network formation, and to attenuate Hypoxia Inducible Factor 1 Subunit Alpha (HIF-1α) stabilization under hypoxic conditions. Notably, MR-39 exhibited significant anti-inflammatory effects, as evidenced by the downregulation of pro-inflammatory genes, including Cyclooxygenase 2 (COX-2), Chemokine (C-X-C Motif) Ligand 7. (CXCL-7), Nuclear Factor Kappa B Subunit 1 (NFKB1), Interleukin 1 Beta (IL-1β), and Interleukin 6 (IL6), and the inhibition of NF-κB protein levels. CONCLUSION: This study identifies MR-39 as a potent modulator of FPR2, and identifies its mechanisms of action in GBM, such as anti-tumor activity, including S-phase arrest, inhibition of EMT, and suppression of both angiogenesis and hypoxic adaptation. By directing FPR2 signaling toward an anti-tumor profile, MR-39 represents a promising therapeutic candidate for GBM.