title: HOXA9 inhibits migration of lung cancer cells and its hypermethylation is associated with recurrence in non-small cell lung cancer.
abstract: This study was aimed at understanding the clinicopathological significance of HOXA9 hypermethylation in non-small cell lung cancer (NSCLC). HOXA9 hypermethylation was characterized in six lung cancer cell lines, and its clinicopathological significance was analyzed using methylation-specific PCR in 271 formalin-fixed paraffin-embedded tissues and 27 fresh-frozen tumor and matched normal tissues from 298 NSCLC patients, and Ki-67 expression was analyzed using immunohistochemistry. The promoter region of HOXA9 was highly methylated in six lung cancer cell lines, but not in normal bronchial epithelial cells. The loss of expression was restored by treatment of the cells with a demethylating agent, 5-aza-2'-deoxycytidine (5-Aza-dC). Transient transfection of HOXA9 into H23 lung cancer cells resulted in the inhibition of cell migration but not proliferation. Conversely, sequence-specific siRNA-mediated knockdown of HOXA9 enhanced cell migration. The mRNA levels of HOXA9 in 27 fresh-frozen tumor tissues were significantly lower than in matched normal tissues (P<0.0001; Wilcoxon signed-rank test). HOXA9 hypermethylation was found in 191 (70%) of 271 primary NSCLCs. HOXA9 hypermethylation was not associated with tumor size (P=0.12) and Ki-67 proliferation index (P=0.15). However, patients with HOXA9 hypermethylation had poor recurrence-free survival (hazard ratio=3.98, 95% confidence interval = 1.07-17.09, P=0.01) in never-smokers, after adjusting for age, sex, tumor size, adjuvant therapy, pathologic stage, and histology. In conclusion, the present study suggests that HOXA9 inhibits migration of lung cancer cells and its hypermethylation is an independent prognostic factor for recurrence-free survival in never-smokers with NSCLC.
authors.affiliation: Cancer Genomics Branch, Research Institute, National Cancer Center, Goyang-si, Korea.
authors.forename: Jung-Ah
authors.initials: JA
authors.lastname: Hwang
authors.affiliation: Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Korea.
authors.forename: Bo Bin
authors.initials: BB
authors.lastname: Lee
authors.affiliation: Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Korea.
authors.forename: Yujin
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Cancer Genomics Branch, Research Institute, National Cancer Center, Goyang-si, Korea.
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Hong
authors.affiliation: Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Young-Ho
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Joungho
authors.initials: J
authors.lastname: Han
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Young Mog
authors.initials: YM
authors.lastname: Shim
authors.affiliation: Cancer Genomics Branch, Research Institute, National Cancer Center, Goyang-si, Korea.
authors.forename: Chae-Yeong
authors.initials: CY
authors.lastname: Yoon
authors.affiliation: Cancer Genomics Branch, Research Institute, National Cancer Center, Goyang-si, Korea.
authors.forename: Yeon-Su
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Korea.
authors.forename: Duk-Hwan
authors.initials: DH
authors.lastname: Kim
mesh_terms: D000368:Aged; D001483:Base Sequence; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000473:pathology*; D045744:Cell Line, Tumor; D019175:DNA Methylation; D017931:DNA Primers; D005260:Female; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D016133:Polymerase Chain Reaction; D016019:Survival Analysis
chemical_list: D017931:DNA Primers; D018398:Homeodomain Proteins; C097899:homeobox protein HOXA9
keywords: HOXA9; hypermethylation; lung cancer; migration; recurrence