DNA methylation profile during multistage progression of pulmonary adenocarcinomas

Abstract

Multiple genetic and epigenetic alterations are known to be involved in the carcinogenesis of peripheral pulmonary adenocarcinoma (ADC). However, epigenetic abnormalities have not been extensively investigated in the following multistage progression sequence: atypical adenomatous hyperplasia (AAH) to adenocarcinoma in situ (AIS), to invasive ADC. To determine the potential role of promoter methylation during ADC development of the lung, we examined methylation status in 20 normal, 20 AAH, 30 AIS, and 60 ADC lung tissues and compared methylation status among the lesions. The MethyLight assay was used to determine the methylation status of 18 CpG island loci, which were hypermethylated in ADC compared to noncancerous lung tissues. The mean number of methylated CpG island loci was significantly higher in ADC than in AAH and AIS, (p < 0.003 between ADC and AAH, p < 0.005 between ADC and AIS). Aberrant methylation of HOXA1, TMEFF2, and RARB was frequently observed in preinvasive lesions, including AAH and AIS. Furthermore, methylation of PENK, BCL2, RUNX3, DLEC1, MT1G, GRIN2B, CDH13, CCND2, and HOXA10 was significantly more frequent in invasive ADC than AAH or AIS. Our results indicate that epigenetic alterations are involved in the multistep progression of pulmonary ADC development, and aberrant CpG island methylation accumulates during multistep carcinogenesis. In addition, aberrant methylation of HOXA1, TMEFF2, and RARB occurred in preinvasive lesions, which indicates that epigenetic alterations of these genes are involved in the early stages of pulmonary ADC development. In contrast, hypermethylation of PENK, BCL2, RUNX3, DLEC1, MT1G, GRIN2B, CDH13, CCND2, and HOXA10 was more frequent in invasive ADC than in preinvasive lesions, which indicates that methylation of these genes occurs later during tumor invasion in the AAH-AIS-ADC sequence.

Promoter Methylation Profiles between Human Lung Adenocarcinoma Multidrug Resistant A549/Cisplatin (A549/DDP) Cells and Its Progenitor A549 Cells

“…30,31) RAS association domain family gene 1 (RASSF1) is a recently discovered RAS family-related gene that modulates multiple apoptotic and cell-cycle checkpoint pathways and promotes microtubule stability. RASSF1A, one isoform of RASSF1, has been identified as a tumour suppressor gene whose inactivation has been implicated in the development of many cancers, especially lung cancer.…”

Methylation of TMEFF2 Gene in Tissue and Serum DNA from Patients with Non-Small Cell Lung Cancer

“…In addition, it is likely that TMEFF2 methylation could be related to other environmental factors rather than tobacco smoking. Notably, the prevalence of TMEFF2 methylation in NSCLCs is approximately an intermediate value compared with the results of the two groups showing a 72% to 30% frequency in lung ACs (Chung et al, 2011;Suzuki et al, 2005). These discrepancies may be attributable to methodological or geographical differences.…”

“…Moreover, TMEFF2 is mapped to human chromosome 2q32.3, where frequent loss of heterozygosity is seen in various human tumors (Beder et al, 2003;Otsuka et al, 1996;Takita et al, 2001) and is frequently hypermethylated in various human cancers (Lin et al, 2011;Suzuki et al, 2005;Young et al, 2001). In particular, chip-based analysis has shown that TMEFF2 gene is identified to have a distinct methylation pattern in nonsmall cell lung cancers (NSCLCs) compared to normal tissues (Field et al, 2005), and TMEFF2 methylation has been reported to frequently occur in the precancerous lesion and early stage of lung adenocarcinoma (AC), such as atypical adenomatous hyperplasia and bronchioloaveolar cell carcinoma (Chung et al, 2011;Selamat et al, 2011). Importantly, aberrantly methylated markers identified in lung tissue samples can be detected in peripheral blood, providing a valuable approach to non-invasive screening for early detection of lung cancer (Bremnes et al, 2005).…”

Synergistic antineoplastic action of 5-aza-2'deoxycytidine (decitabine) in combination with different inhibitors of enhancer of zeste homolog 2 (EZH2) on human lung carcinoma cells

“…RUNX3 is frequently silenced by DNA hyper-methylation in many cancers, including lung cancer [39][40][41]. RUNX3 methylation correlates with clinical stage and degree of differentiation in NSCLC [42].…”