Expression of substance P and neurokinin-1 receptor in nasopharyngeal carcinoma and their clinical significance

Abstract

Objective To investigate the expression of substance P (SP) and its receptor, neurokinin-1 receptor (NK-1R), in nasopharyngeal carcinoma (NPC) tissues and their correlation with the clinicopathological parameters of the patients. Methods Real-time fluorescence quantitative PCR (RT-qPCR) and Western blotting were used to detect the expression of SP and NK-1R mRNAs in the specimen of tumor tissues of NPC patients and normal tissues from patients with deviated nasal septum, and their protein expression and distribution in the tissues were observed using immunohistochemistry. Chi-square test was used to analyze the correlation of the expression of SP and NK-1R with the clinicopathological characteristics of the patients. CCK8 and Transwell assays were used to evaluate the effects of SP on the proliferation and invasion of HNE1 cells. Results The mRNA levels of SP and NK-1R were significantly increased in NPC tissues (7.96±1.75 and 7.12±1.54, respectively) as compared with the normal tissues (1.05±0.34, 1.04±0.2; P < 0.01); the protein expression of SP and NK-1R were also significantly upregulated in the NPC tissues (1.18±0.27 and 0.81±0.17, respectively) in comparison with the normal tissues (0.56±0.06, 0.48±0.05; P < 0.01). The positive expression rate of SP and NK-1R in the NPC tissues was 64% and 68%, respectively, significantly higher than the rates in normal tissues (11% and 22%, respectively; P < 0.01). The positive expression rates of SP and NK-1R were significantly higher in stage Ⅲ and stage Ⅳ NPC cases than in stage Ⅰ-Ⅱ cases (P < 0.05). Exogenous SP significantly enhanced the proliferation (P < 0.05) and invasion (P < 0.01) of HNE1 cells in vitro. Conclusion SP and NK-1R are over-expressed in NPC tissues, and their expression levels are correlated with the TNM stages of NPC, suggesting their value as potential new targets for diagnosis and treatment of NPC.

Keywords

• nasopharyngeal carcinoma
• substance p
• neurokinin-1 receptor