Tac2-N acts as a novel oncogene and promotes tumor metastasis via activation of NF-κB signaling in lung cancer

• Published in: Journal of experimental & clinical cancer research 2019-08, Vol.38 (1), p.319-10, Article 319
• Main Authors: Hao, Xianglin, Gao, Li-Yun, Zhang, Ning, Chen, Hongqiang, Jiang, Xiao, Liu, Wenbin, Ao, Lin, Cao, Jia, Han, Fei, Liu, Jinyi
• Format: Article
• Language: English
• Subjects: Animals; Cell Line, Tumor; Disease Models, Animal; Female; Heterografts; Humans; Kinases; Lung cancer; Lung Neoplasms - genetics; Lung Neoplasms - metabolism; Lung Neoplasms - pathology; Male; Metastasis; Mice; Neoplasm Metastasis; NF-kappa B - metabolism; NF-κB signaling pathway; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Oncogenes; Signal Transduction; Tac2-N; Transfection; Tumors
• ISSN: 1756-9966; 0392-9078; 1756-9966
• DOI: 10.1186/s13046-019-1316-7

High rates of recurrence and metastasis are the major cause of the poor outcomes for patients with lung cancer. In previous research, we have demonstrated that Tac2-N promotes tumor growth by suppressing p53 signaling in lung cancer. Beyond that, other biological functions and clinical significance of Tac2-N in lung cancer progression are still unknown. Tissue microarrays of 272 lung cancer patients were constructed to assess the association of Tac2-N expression and prognosis of lung cancer patients with different clinical stages. The protein expression of Tac2-N in metastatic and non-metastatic specimens were detected by IHC. In vitro migration and invasion and in vivo nude mice metastasis model were used to evaluate the effect of Tac2-N ectopic expression on metastasis capability of lung cancer cells. The downstream signaling pathway of Tac2-N was explored using luciferase reporter assays and WB. The expression of Tac2-N was associated with advanced stages, but not with early stages (P = 0.513). Tac2-N expression is sharply overexpressed in metastatic tumors compared with non-metastatic tumors. In vitro and in vivo assays suggested that Tac2-N facilitated migration and invasion of lung cancer cells in vitro and promoted tumor metastasis in vivo. Mechanistically, Tac2-N increased the degradation of IκB by promoting its phosphorylation, and subsequently activated NF-κB activity by facilitating the nuclear translocation of NF-κB and stimulating the transcription of targets, MMP7 and MMP9. Notably, the C2B domain of Tac2-N was crucial for Tac2-N to activate NF-κB signal. Blockage of NF-κB by shRNA or inhibitor attenuates the function of Tac2-N in the promotion of metastasis. Our study provided proof of principle to show that Tac2-N serves as a novel oncogene gene and plays an important role in the progression and metastasis of lung cancer.