NKX2-1-mediated p53 expression modulates lung adenocarcinoma progression via modulating IKKβ/NF-κB activation

// Po-Ming Chen 1 , Tzu-Chin Wu 2 , Ya-Wen Cheng 1 , Chih-Yi Chen 3  and Huei Lee 1 1 Graduate Institute of Cancer Biology and Drug Discovery, Taipei Medical University, Taipei City, Taiwan 2 Division of Chest Medicine, Department of Internal Medicine, Chung Shan Medical University Hospital, Taichung, Taiwan 3 Department of Surgery, China Medical University Hospital, Taichung, Taiwan Correspondence to: Huei Lee, email: // Keywords : NKX2-1, p53, IKKβ, lung adenocarcinoma Received : December 11, 2014 Accepted : March 04, 2015 Published : March 30, 2015 Abstract NKX2-1 plays a dual role in lung adenocarcinoma progression, but the underling mechanism is not fully understood. In the present study, we provide evidence that NKX2-1 directly regulates p53 transcription, and in turn, NKX2-1 elevates the mutant p53/NF-Y complex to up-regulate IKKβ transcription in p53-mutant cells, but NKX2-1-mediated wild-type p53 down-regulates IKKβ transcription via decreased Sp1 binding to IKKβ promoter in p53-WT cells. The IKKβ-mediated p65 nuclear localization and epithelial-to-mesenchymal transition (EMT) modulated by the NKX2-1/p53 axis is responsible for soft-agar growth, invasion, and xenograft tumour formation. Among patients, high-IKKβ mRNA tumours had higher prevalence in p53-mutant or nuclear p65 tumours than their counterparts, but not related with NKX2-1 mRNA expression. However, when tumours were divided into p53-WT and p53-mutant subgroups, NKX2-1 mRNA expression was negatively correlated with IKKβ mRNA in p53-WT subgroup, but positively related with IKKβ mRNA expression in p53-mutant subgroup. Kaplan-Meier and Cox regression analysis indicated that high NKX2-1 mRNA tumours exhibited poorer overall survival and relapse free survival than low NKX2-1 mRNA tumours in p53-WT subgroup, but the opposite was observed in p53-mutant subgroup. Therefore, we suggest that NKX2-1 as a tumour suppressor or a tumour promoter in lung adenocarcinoma progression is dependent on p53 status.