Sympathetic modulation of tumor necrosis factor alpha-induced nociception in the presence of oral squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) causes more severe pain and psychological stress than other types of cancer. Despite clinical evidence linking pain, stress, and cancer progression, the underlying relationship between pain and sympathetic neurotransmission in oral cancer is unknown. We found that human HNSCC tumors and mouse tumor tissue are innervated by peripheral sympathetic and sensory nerves. Moreover, [beta]-adrenergic 1 and 2 receptors ([beta]-AR) are overexpressed in human oral cancer cell lines, and norepinephrine treatment increased [beta]-AR2 protein expression as well as cancer cell proliferation in vitro. We have recently demonstrated that inhibition of tumor necrosis factor alpha (TNF[alpha]) signaling reduces oral cancer-induced nociceptive behavior. Norepinephrine-treated cancer cell lines secrete more TNF[alpha] which, when applied to tongue-innervating trigeminal neurons, evoked a larger Ca2+ transient; TNF-TNFR inhibitor blocked the increase in the evoked Ca2+ transient. Using an orthotopic xenograft oral cancer model, we found that mice demonstrated significantly less orofacial cancer-induced nociceptive behavior during systemic [beta]-adrenergic inhibitory treatment with propranolol. Furthermore, chemical sympathectomy via guanethidine led to a significant reduction in tumor size and nociceptive behavior. We infer from these results that sympathetic signaling modulates oral cancer pain via TNF[alpha] secretion and tumorigenesis. Further investigation of the role of neuro-cancer communication in cancer progression and pain is warranted. (C) 2022 International Association for the Study of Pain.