BackgroundH19 was the first long non-coding RNA (lncRNA) to be confirmed. Recently, studies have suggested that H19 may participate in lung cancer (LC) development and progression. This study assessed whether single nucleotide polymorphisms (SNPs) in H19 are associated with the risk of LC in a Chinese population.MethodsA case-control study was performed, and H19 SNP rs217727 was analyzed in 555 lung cancer patients from two hospitals and 618 healthy controls to test the association between this SNP and the susceptibility to LC.ResultsThe A/A homozygous genotype of rs217727 was significantly associated with an increased LC risk (odds ratio (OR) = 1.661, 95% confidence interval (CI) = 1.155 to 2.388, P = 0.006). Significant associations remained after stratification by smoking status (P < 0.001). Furthermore, the A/A genotype had a higher risk of LC than those of G/G in the squamous cell carcinoma (OR = 2.022, P = 0.004) and adenocarcinoma (OR = 1.606, P = 0.045) subgroups.ConclusionsThe rs217727 SNP in lncRNA H19 was significantly associated with susceptibility to LC, particularly in squamous cell carcinoma and adenocarcinoma, and identified the homozygous A/A genotype as a risk factor for LC.

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MicroRNA-7 (miR-7) has been identified as a tumor suppressor in non-small cell lung cancer (NSCLC) and a radiosensitivity regulator. Numerous studies have revealed that specific protein 1 (SP1) plays a critical role in the tumorigenesis of various types of cancers and regulates radiosensitivity and tumor suppressor p53-binding protein 1 (TP53BP1), which plays an essential role in DNA repair. However, it is not clear whether miR-7 has a regulatory effect on SP1 and TP53BP1 in NSCLC. In the present study it was revealed that miR-7 directly binds to the 3′UTR of SP1, thereby suppressing SP1 expression to regulate radiosensitivity. Overexpression of miR-7 and SP1 and knockdown of miR-7 and SP1 were performed using lentiviral transfection. Protein and mRNA abundance of SP1 and TP53BP1 were determined using western blotting and RT-qPCR, respectively, while miR-7 binding to SP1 was validated using a luciferase reporter assay. Biological function analysis indicated that miR-7 negatively regulated SP1 and inhibited cell proliferation, migration, and invasion when combined with radiation. It was also revealed that the expression of TP53BP1 was positively regulated by SP1 or negatively regulated by miR-7. In conclusion, SP1 was a target of miR-7, and the decreased expression of SP1 resulting from miR-7 overexpression in NSCLC was vital for improving radiosensitivity in NSCLC cells. Moreover, SP1 expression was detected in 95 paired NSCLC and adjacent normal tissues, and it was determined that SP1 was significantly upregulated in NSCLC tissues and that its upregulation was correlated with the degree of tissue differentiation. Thus, SP1 and/or miR-7 may be potential molecular targets in NSCLC radiotherapy.