Crosstalk of NPY and TGFβ orchestrates the signaling to facilitate perineural invasion of oral squamous cell carcinoma

Abstract Background Perineural invasion (PNI) frequently occurs in oral squamous cell carcinoma (OSCC) and predicts poor prognosis. Although PNI is increasingly recognised as a process driven by tumour-nerve crosstalk, the underlying molecular mechanisms remain unclear. We investigated the role of sympathetic nerve–derived neuropeptide Y (NPY) and its receptor NPY1R in OSCC PNI. Methods NPY/NPY1R expression was assessed in human OSCC tissues by immunostaining, qPCR, and TCGA data analysis. Functional studies using Cal27 and SCC9 cells included migration, invasion, and sphere assays. The causal role of NPY1R was tested by lentiviral knockdown/overexpression, validated in tongue orthotopic xenografts, and further examined by NPY1R pharmacological inhibition in vivo. Results NPY was enriched in the PNI microenvironment, and malignant OSCC expressed high NPY1R, particularly at invasive fronts. Mechanistically, NPY activated ERK and Smad2 via NPY1R, synergising with TGFβ signalling in tumour cells expressing TβRI. This crosstalk enhanced proliferation, invasion, and PNI in vivo. Importantly, NPY1R inhibition markedly reduced tumour growth, metastasis, and PNI. Conclusions We identify NPY-NPY1R-TGFβ crosstalk as a novel mechanism enabling OSCC to exploit neural signals for PNI, highlighting a promising therapeutic target to block neural invasion and improve patient outcomes.