cAMP/CREB-regulated LINC00473 marks LKB1-inactivated lung cancer and mediates tumor growth
Zirong Chen, … , Frederic J. Kaye, Lizi Wu
Zirong Chen, … , Frederic J. Kaye, Lizi Wu
Published May 3, 2016
Citation Information: J Clin Invest. 2016;126(6):2267-2279. https://doi.org/10.1172/JCI85250.
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cAMP/CREB-regulated LINC00473 marks LKB1-inactivated lung cancer and mediates tumor growth

Abstract

The LKB1 tumor suppressor gene is frequently mutated and inactivated in non–small cell lung cancer (NSCLC). Loss of LKB1 promotes cancer progression and influences therapeutic responses in preclinical studies; however, specific targeted therapies for lung cancer with LKB1 inactivation are currently unavailable. Here, we have identified a long noncoding RNA (lncRNA) signature that is associated with the loss of LKB1 function. We discovered that LINC00473 is consistently the most highly induced gene in LKB1-inactivated human primary NSCLC samples and derived cell lines. Elevated LINC00473 expression correlated with poor prognosis, and sustained LINC00473 expression was required for the growth and survival of LKB1-inactivated NSCLC cells. Mechanistically, LINC00473 was induced by LKB1 inactivation and subsequent cyclic AMP–responsive element–binding protein (CREB)/CREB-regulated transcription coactivator (CRTC) activation. We determined that LINC00473 is a nuclear lncRNA and interacts with NONO, a component of the cAMP signaling pathway, thereby facilitating CRTC/CREB-mediated transcription. Collectively, our study demonstrates that LINC00473 expression potentially serves as a robust biomarker for tumor LKB1 functional status that can be integrated into clinical trials for patient selection and treatment evaluation, and implicates LINC00473 as a therapeutic target for LKB1-inactivated NSCLC.

Authors

Zirong Chen, Jian-Liang Li, Shuibin Lin, Chunxia Cao, Nicholas T. Gimbrone, Rongqiang Yang, Dongtao A. Fu, Miranda B. Carper, Eric B. Haura, Matthew B. Schabath, Jianrong Lu, Antonio L. Amelio, W. Douglas Cress, Frederic J. Kaye, Lizi Wu

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Figure 1

lncRNA profiling revealed that LINC00473 is induced by LKB1 loss in NSCLC cells.

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lncRNA profiling revealed that LINC00473 is induced by LKB1 loss in NSCL...
(A) Western blot analysis of expression of LKB1-WT or kinase-dead K78I mutant in transduced LKB1-null lung adenocarcinoma A549 cells. A549 cells infected with pBabe vector retroviruses were used as controls (Ctl). (B and C) Volcano plots show differentially expressed lncRNAs after expression of LKB1-WT (B) or LKB1-K78I mutant (C) in A549 cells by lncRNA microarray (V3.0) analysis. The cutoff criteria was an absolute fold-change of ≥2 and P < 0.05. (D) A volcano plot shows differentially expressed lncRNAs in two LKB1-null cell lines (A549 and H460) as compared with two LKB1-WT cell lines (H322 and H3123). (E) A heatmap shows expression levels of several LKB1-regulated protein-coding and noncoding genes measured in NanoString assays. (F and G) Two LINC00473 (Lnc473) transcript variants (tv1: NR_026860 and tv2: NR_026861) show significantly elevated expression in LKB1-mutant (Mut) groups as compared with LKB1-WT groups based on the NanoString assays. (H) CCLE data analysis identified NSCLC cell lines (n = 130) with outlier LINC00473 expression levels. (I) Enhanced LINC00473 expression was significantly associated with LKB1 mutations in CCLE NSCLC cell lines. See also Supplemental Figures 1–3 and Supplemental Tables 1–6.