BackgroundReprogrammed energy metabolism as an emerging hallmark of cancer has recently drawn special attention since it facilitate cell growth and proliferation. Recently, long noncoding RNAs (lncRNAs) have been served as key regulators implicated in tumor development and progression by promoting proliferation, invasion and metastasis. However, the associations of lncRNAs with cellular energy metabolism in lung cancer (LC) need to be clarified.MethodsHere, we conducted bioinformatics analysis and found insulin-like growth factor binding protein 4–1 (IGFBP4–1) as a new candidate lncRNA located in the upstream region of IGFBP4 gene. The expression levels of lnc-IGFBP4–1, mRNA levels of IGFBP4 in 159 paired lung cancer samples and adjacent, histological normal tissues by qRT-PCR. Over-expression and RNA interference (RNAi) approaches were adopted to investigate the biological functions of lnc-IGFBP4–1. The intracellular ATP level was measured using the Cell Titer-Glo Luminescent Cell Viability Assay kit, and changes in metabolic enzymes were examined in cancer cells and normal pulmonary epithelial cells with qRT-PCR.ResultsOur results showed that lnc-IGFBP4–1 was significantly up-regulated in LC tissues compared with corresponding non-tumor tissues (P < 0.01), and its expression level was significantly correlated with TNM stage (P < 0.01) and lymph node metastasis (P < 0.05). Further investigation showed that overexpression of lnc-IGFBP4–1 significantly promoted LC cell proliferation in vitro and in vivo, while downregulation of endogenous lnc-IGFBP4–1 could inhibited cell proliferation and induce apoptosis. Moreover, we found lnc-IGFBP4–1 could influences ATP production levels and expression of enzymes including HK2, PDK1 and LDHA, in addition, decline in both ATP production and these enzymes in response to 2-DG and 2-DG-combined Rho123, respectively, was observed in lnc-IGFBP4–1-overespressing LC cells, indicative of an enhanced aerobic glycolysis rate. Finally, lnc-IGFBP4–1 was observed to negatively correlate with gene IGFBP4, and lower expression level of IGFPB4 was found after lnc-IGFBP4–1-overexpression was transfected into PC9 cells, higher expression level of IGFPB4 was also found after lnc-IGFBP4–1-downregulation was transfected into GLC-82 cells, which indicates that IGFBP4 may exert its targeting function regulated by lnc-IGFBP4–1.ConclusionsTaken together, these findings provide the first evidence that lnc-IGFBP4–1 is significantly up-regulated in LC tissues and plays a positive role in cell proliferation and metastasis through possible mechanism of reprogramming tumor cell energy metabolism, which suggests that lnc-IGFBP4–1 may be a promising biomarker in LC development and progression and as a potential therapeutic target for LC intervention.Electronic supplementary materialThe online version of this article (10.1186/s12943-017-0722-8) contains supplementary material, which is available to authorized users.

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WW domain-containing oxidoreductase (WWOX) is a tumor suppressor that has been reported to lose function due to genetic alterations in several cancers. WWOX maps to the common chromosomal fragile site FRA16D and several copy number variations (CNVs) were found within this gene. In this study, we investigated the association between the CNVs of WWOX and lung cancer risk in four independent case-control studies, which are on 2942 lung cancer cases and 3074 cancer-free controls of southern, eastern and northern Chinese. A common CNV-67048 was genotyped by the Taqman real-time PCR, and its biological effect was accessed with protein expression and sequencing assays. We found that in comparison with the common 2-copy genotype, the carriers of loss variant genotypes (1-copy or 0-copy) had a significantly increased risk of lung cancer (adjusted OR = 1.39, 95% CI = 1.24-1.55, P = 9.01×10(-9)) in a dose-response manner (Ptrend = 1.12 × 10(-10)), and the WWOX protein expressions in lung cancer tissues were significantly lower (P = 0.036), accompanying a higher rate of exons absence (P = 0.021) in subjects with loss genotypes of CNV-67048. Our data suggest that the loss genotypes of CNV-67048 in WWOX predispose their carriers to lung cancer; this might be related with altered WWOX gene expression and exons absence in them.

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Recently, several genome-wide association studies (GWAS) have identified many susceptible single nucleotide polymorphisms (SNPs) for chronic obstructive pulmonary disease (COPD) and lung cancer which are two closely related diseases. Among those SNPs, some of them are shared by both the diseases, reflecting there is possible genetic similarity between the diseases. Here we tested the hypothesis that whether those shared SNPs are common predictor for risks or prognosis of COPD and lung cancer. Two SNPs (rs6495309 and rs1051730) located in nicotinic acetylcholine receptor alpha 3 (CHRNA3) gene were genotyped in 1511 patients with COPD, 1559 lung cancer cases and 1677 controls in southern and eastern Chinese populations. We found that the rs6495309CC and rs6495309CT/CC variant genotypes were associated with increased risks of COPD (OR = 1.32, 95% C.I. = 1.14–1.54) and lung cancer (OR = 1.57; 95% CI = 1.31–1.87), respectively. The rs6495309CC genotype contributed to more rapid decline of annual Forced expiratory volume in one second (FEV1) in both COPD cases and controls (P<0.05), and it was associated with advanced stages of COPD (P = 0.033); the rs6495309CT/CC genotypes conferred a poor survival for lung cancer (HR = 1.41, 95%CI = 1.13–1.75). The luciferase assays further showed that nicotine and other tobacco chemicals had diverse effects on the luciferase activity of the rs6495309C or T alleles. However, none of these effects were found for another SNP, rs1051730G>A. The data show a statistical association and suggest biological plausibility that the rs6495309T>C polymorphism contributed to increased risks and poor prognosis of both COPD and lung cancer.

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CD133 is a pivotal marker of cancer stem cells (CSCs), which is involved in tumorigenesis and cancer progression. Recent studies have identified CD133 to be a prognostic factor for cancer rested with its expression and genetic variants. Here, we hypothesized that the single nuclear polymorphisms (SNPs) in CD133 may be associated with lung cancer risk and prognosis. Based on three independent case-control analyses with a total of 2332 lung cancer cases and 2457 controls, the gene-based association analysis with 13 polymorphisms of CD133 suggested that CD133 is a susceptible gene for lung cancer (P = 0.043) and that the SNP rs2240688A>C in the 3'-untranslated region of CD133 is the most significant associated SNP with the risk of lung cancer (P = 0.020); further analysis showed that the rs2240688C variant genotypes (CA+CC) harbored a decreased risk of lung cancer (odds ratio = 0.80; 95% confidence interval (CI) = 0.72-0.90) and conferred a favorable survival for lung cancer patients (median survival time: 15 months) compared with AA genotype (median survival time: 11 months, log-rank test: P = 3.31 × 10(-6); Cox model: hazards ratio = 0.81, 95% CI = 0.70-0.94). Functional assays revealed that the rs2240688A to rs2240688C transition gained a new binding of the microRNA hsa-miR-135a/b and decreased the CD133 expression. Our data suggest that the functional polymorphism rs2240688A>C in CD133 is associated with lung cancer risk and survival. This SNP may be a functional biomarker to predict risk and prognosis of lung cancer.

Purpose: This study was implemented to investigate the associations between SNP in mature microRNA (miRNA) sequence and lung cancer prognosis and to verify the function of those SNP.Experimental Design: Eight SNPs (rs3746444T>C in hsa-mir-499, rs4919510C>G in hsa-mir-608, rs13299349G>A in hsa-mir-3152, rs12220909G>C in hsa-mir-4293, rs2168518G>A in hsamir-4513, rs8078913T>C in hsa-mir-4520a, rs11237828T>C in hsa-mir-5579, and rs9295535T>C in hsa-mir-5689) were analyzed in a southern Chinese population with 576 patients with lung cancer, and the significant results were validated in two additional cohorts of 346 and 368 patients, respectively. A series of experiments were performed to evaluate the relevancies of those potentially functional SNPs.Results: We found that the microRNA-499 rs3746444T>C polymorphism exhibited a consistently poor prognosis for patients with lung cancer in the discovery set [HR, 1.24; 95% confidence interval (CI), 1.02-1.49; P ¼ 0.028], in the validation set I (HR, 1.31; 95% CI, 1.01-1.71; P ¼ 0.048) and in the validation set II (HR, 1.45; 95% CI, 1.12-1.86; P ¼ 0.004). The adverse effect of CT/CC variants was more remarkable in patients receiving platinum-based chemotherapy. Further functional assays demonstrated that the rs3746444C variant allele influences the expression of several cancer-related genes and affects lung cancer cells' proliferation and tumor growth in vivo and in vitro via the cisplatinum resistance.Conclusion: Our findings suggested that the rs3746444T>C polymorphism in mature miR-499 sequence could contribute to poor prognosis by modulating cancer-related genes' expression and thus involve tumorigenesis and anti-chemotherapy, which may be a useful biomarker to predict lung cancer patients' prognosis.