Downregulation of RECK by promoter methylation correlates with lymph node metastasis in non-small cell lung cancer.
In the present study, we addressed the molecular mechanism of the downregulation of reversion-inducing-cysteine-rich protein with Kazal motifs (RECK), a critical tumor suppressor that can potently inhibit angiogenesis and metastasis, in non-small cell lung cancer and its clinical significance. The methylation status of the RECK gene promoter was studied by methylation-specific polymerase chain reaction. RECK mRNA and protein levels were investigated by reverse transcription-polymerase chain reaction and western blot analysis. Downregulation of RECK was observed in 60% of the 55 tumors analyzed. Using methylation-specific polymerase chain reaction analysis methylation of the RECK promoter was detected in 63.6% (35/55) of the tumor tissues. A strong correlation between downregulation and promoter methylation was found in these tumors (P = 0.000005). More importantly, downregulation of RECK significantly correlated with lymph node metastasis (P = 0.038). Mutation of codon 12 of the K-ras gene was detected in 25.5% (14/55) of lung tumor tissues. Statistical analysis indicated that K-ras mutation was linked with RECK promoter methylation (P = 0.047) and downregulation (P = 0.023). Promoter methylation was also detected in human lung cancer cell lines, and the DNA methyltransferase inhibitor 5'-azacytidine reversed the expression of RECK and reduced the invasive ability of these cell lines. Collectively, our results suggest that downregulation of the metastasis suppressor RECK is caused by promoter methylation in non-small cell lung cancer and is associated with K-ras mutation and lymph node metastasis.
Chang
Huang-Chou
HC
Department of Chest Surgery, Kaohsiung Veterans General Hospital, 386, Ta-Chung 1st Road, Kaohsiung 813, Taiwan.
Cho
Chun-Yu
CY
Hung
Wen-Chun
WC
D000368:Aged; D020816:Amino Acid Motifs; D001374:Azacitidine / Q000494:pharmacology; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002460:Cell Line; D019175:DNA Methylation; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics*; D005260:Female; D058851:GPI-Linked Proteins; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000235:genetics; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D009361:Neoplasm Invasiveness; D011401:Promoter Regions, Genetic / Q000235:genetics*; D018631:ras Proteins / Q000235:genetics
D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; C115460:RECK protein, human; D018631:ras Proteins; D001374:Azacitidine