Figure 1.

Effect of cigarette smoke on the expression and promoter methylation of Leucine Zipper Down-Regulated in Cancer 1 (LDOC1) in human lung cells. (A) Locations of quantitative Methylation-Specific PCR (qMSP) primer pairs in the CpG island proximal to the LDOC1 transcription start site. (B–D) The promoter DNA methylation (upper in B, left in C and D) and the mRNA expression (bottom in B, right in C and D) of LDOC1 in lung cancer cell lines and BEAS-2B bronchial epithelial cells (B) or in the A549 lung adenocarcinoma(LADC) alveolar basal epithelial cell line with or without 5AzaC treatment (C) or in BEAS-2B cells after exposure to the indicated concentrations of cigarette smoke condensate (CSC) for 4 or 6 weeks (D) were measured using qMSP and qPCR, respectively. Dimethyl sulfoxide (DMSO) treatment was used as control. Universally methylated and unmethylated DNA (Chemicon) were used as positive (PC) and negative controls (NC) in qMSP, respectively. Data are presented as mean ± SD (n = 3), analyzed using a Student’s t-test. * p < 0.05; ** p < 0.01. (E) The DNA methylation profiles of LDOC1 in LADC [17] were obtained using TCGA.