Neuropilin-2 Mediates Radioresistance in Nasopharyngeal Carcinoma via Wnt/β-Catenin Pathway.

PURPOSE: Neuropilin-2 (NRP2) is linked to poor prognosis in several malignant tumors. We elucidated the role of NRP2 in radiation resistance in nasopharyngeal carcinoma (NPC) and the underlying molecular pathways. MATERIAL AND METHODS: CNE-2R cells of NPC were used for NRP2 knockdown. Stable NRP2 knockdown was achieved using three siRNAs targeting distinct regions of the NRP2 gene. The effect of NRP2 knockdown was confirmed through qPCR for mRNA and Western blot (WB) for protein levels. Assays for cell viability and colony formation were conducted to assess cellular responses to NRP2 knockdown and ionizing radiation. Bioinformatics analyses, including differential expression and pathway enrichment using GEO datasets and GSEA analysis, were performed to elucidate the molecular mechanisms underlying NRP2 function. RESULTS: After NRP2 knockdown in CNE-2R cells, NRP2 expression was significantly lower compared to non-knockdown cells by qPCR and Western blot analysis. NRP2 downregulation in CNE-2R cells led to decreased proliferation and clonal numbers post-radiation in comparison to the control group (P < 0.001). Analysis of the GEO database exhibited that NRP2 expression was notably elevated in nasopharyngeal carcinoma tissues vs normal tissues (p = 0.012). GSEA analysis showed a notable enhancement of the Wnt/β-catenin signaling pathway in NPC, with NES = 1.647, p adjust = 0.049, and FDR = 0.038. The WB analysis indicated that NRP2 knockdown notably reduced the level of WNT3a, Axin2, Cyclin D1, p-GSK3β, and β-catenin in the Wnt/β-catenin pathway in comparison to the negative control group (p < 0.05), with GSK3β expression remaining unchanged. CONCLUSION: NRP2 is connected with radioresistance in NPC, potentially via Wnt/β-catenin pathway, and may be a potential therapeutic target.