DNA methylation and histone modification regulate silencing of OPG during tumor progression
Journal
Journal of Cellular Biochemistry
Journal Volume
108
Journal Issue
1
Pages
315-325
Date Issued
2009
Author(s)
Abstract
The identification of molecules that are down-regulated in malignant phenotype is important for understanding tumor biology and their role in tumor suppression. We compared the expression profile of four normal nasal mucosal (NNM) epithelia and a series of nasopharyngeal cancinoma (NPC) cell lines using cDNA microarray and confirmed the actual expression of the selected genes, and found osteoprotegerin (OPG) to be ubiquitously deficient in NPC cells. We also found OPG to be down-regulated in various cancer cell lines, including oral, cervical, ovarian, lung, breast, pancreas, colon, renal, prostate cancer, and hepatoma. Administration of recombinant OPG (rOPG) brought about a reduction in cancer cell growth through apoptotic mechanism. We generated eleven monoclonal antibodies (MAbs) against OPG to study OPG's expression and biological functions in cancer cells. OPG was detected in the tumor stromal regions, but not in the cancer cell per se in surgical specimens of liver cancer. Quantitative reverse transcription-polymerase chain reaction (Q-RT-PCR) revealed that OPG was downregulated in NPC tissues compared with normal nasal polyp (NNP) tissues. In addition, we showed OPG silencing to be associated with promoter methylation as well as histone modifications. In OPG-silenced cancer cell lines, the OPG gene promoter CpG dinucleotides were highly methylated. Compared to normal cells, silenced OPG gene in cancer cells were found to have reduced histone 3 lysine 4 tri-methylation (H3K4me3) and increased histone 3 lysine 27 tri-methylation (H3K27me3). Taken together, these results suggest that OPG silencing in carcinoma cancer cells occurs through epigenetic repression. ? 2009 Wiley-Liss, Inc.
Subjects
Epigenetic silencing; Nasopharyngeal carcinoma; OPG; Tumor progression
SDGs
Other Subjects
histone H3; monoclonal antibody; osteoprotegerin; article; breast cancer; cancer cell culture; cancer growth; colon cancer; controlled study; DNA methylation; epigenetics; gene silencing; human; human cell; kidney cancer; liver cell carcinoma; lung cancer; mouth cancer; nasopharynx carcinoma; ovary cancer; pancreas cancer; priority journal; prostate cancer; protein processing; reverse transcription polymerase chain reaction; uterine cervix cancer; Cell Line, Tumor; DNA Methylation; Epigenesis, Genetic; Gene Expression Regulation, Neoplastic; Gene Silencing; Histones; Humans; Male; Methylation; Neoplasms; Osteoprotegerin; Prostatic Neoplasms
Type
journal article