Objective:We aimed to detect the role of LINC00472 via regulating miR-24-3p and death effector domain-containing DNA-binding protein in lung adenocarcinoma.Methods:Long noncoding RNA, microRNA, and messenger RNA levels were determined using reverse transcription quantitative polymerase chain reaction. The expression of death effector domain-containing DNA-binding protein was determined using Western blot assay. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and colony formation assay were conducted to explore the proliferation of cells. The cell apoptosis was tested by flow cytometry assay. Target relationships between miR-24-3p, death effector domain-containing DNA-binding protein, and LINC00472 were validated by dual-luciferase reporter gene assay.Results:LINC00472 and death effector domain-containing DNA-binding protein were found to be underexpressed, whereas miR-24-3p was found overexpressed in lung adenocarcinoma cell lines and tissues. Both LINC00472 and death effector domain-containing DNA-binding protein can bind to miR-24-3p. Overexpression of LINC00472 led to higher death effector domain-containing DNA-binding protein level, demoting cell proliferation while promoting apoptosis. Overexpression of miR-24-3p reduced death effector domain-containing DNA-binding protein level, which facilitated cell proliferation and inhibited cell apoptosis, as well as to some extent restrained the effects of LINC00472. The high expression of miR-24-3p in tumor cells was negatively related to LINC00472 and death effector domain-containing DNA-binding protein, whereas the expression of LINC00472 and that of death effector domain-containing DNA-binding protein were positively correlated.Conclusion:Our findings suggested that LINC00472 contributed to the increase in lung adenocarcinoma cell apoptosis and the inhibition of proliferation via regulating miR-24-3p/DEDD, which might provide a novel insight into potential therapeutic approach for lung adenocarcinoma.

The correlation between the expression of DNA methyltransferase-1 (DNMT1) and estrogen receptor α (ERα), as well as the methylation status of ERα, was analyzed to investigate the clinical significance of DNMT1 and ERα in breast cancer. Substance P immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) were utilized to detect the protein and mRNA expression levels of DNMT1 and ERα in 112 breast cancer and 20 normal breast specimens. Methylation specific PCR was utilized to detect the methylation status of ERα in ERα-positive and -negative breast cancer specimens and 20 normal breast specimens. The results of the present study revealed that DNMT1 protein and mRNA levels were low in normal breast specimens (10.00 and 46.05%, respectively) and ERα-positive breast cancer specimens (15.00 and 48.68%, respectively), compared with increased levels in ERα-negative breast cancer specimens (81.11 and 88.89%, respectively; P<0.05). The methylation rate of ERα was highest in ERα-negative breast cancer specimens (86.11%) compared with normal breast specimens and ERα-positive breast cancer specimens (10.00 and 36.84%, respectively; P<0.05). Positive expression of ERα protein was observed to be associated with progesterone receptor expression (P<0.05), however, no such association was observed for age, menopause state, tumor size, number of positive nodes, Tumor-Node-Metastasis stage or tumor type (P>0.05). The protein and mRNA expression levels of DNMT1 were negatively correlated with ERα expression (P<0.05). DNMT1 expression was positively correlated with methylation of ERα (P<0.05), and was positively correlated with the methylation of CpG islands of ERα, indicating that the detection of DNMT1 expression may be significant for the diagnosis and typing of breast cancer.

Our main objective is probing the effect of methylation of CLEC14A on its expression and lung adenocarcinoma (LUAD) progression. Microarray analysis was utilized to screen out differentially downregulated genes with hypermethylation in LUAD tissues. The CLEC14A expression level was measured by western blot analysis and qRT-PCR. Methylation-specific-PCR was performed to evaluate methylation status of CLEC14A. The 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromid (MTT) assay was used to check the relation between CLEC14A expression and cell proliferation. Cell cycle, cell apoptosis, migration, and invasion were respectively detected by the flow cytometry assay, wound healing assay, and transwell assay. Tumor xenograft models were established for investigating the effect of CLEC14A on tumor formation. CLEC14A expression in LUAD tissues was impaired compared with that in adjacent tissues, and CLEC14A promoter was highly methylated in LUAD. Overexpressing CLEC14A or inhibiting the methylation level of CLEC14A in A549 and LTEP-a-2 cells impeded the duplication of LUAD cells, promoted apoptosis, attenuated cell migration, and invasion ability, and arrested cell cycle at the G0/G1 phase. Overexpression of CLEC14A inhibited tumorigenesis of LUAD cells in nude mice. The promoter of CLEC14A is methylated in LUAD, leading to downregulation of CLEC14A in LUAD. CLEC14A acts as an antitumor role in LUAD by suppressing cell proliferation, migration, invasion, promoting cell apoptosis, and reducing tumorigenicity in nude mice. Thus, the inhibition of CLEC14A methylation is a novel strategy for the clinic treatment of LUAD.