SIP1 is downregulated in hepatocellular carcinoma by promoter hypermethylation
Author
Acun, T.
Oztas, E.
Yagci, T.
Yakicier, M.C.
Date
2011Source Title
BMC Cancer
Print ISSN
14712407
Volume
11
Language
English
Type
ArticleItem Usage Stats
214
views
views
178
downloads
downloads
Abstract
Background: Smad interacting protein-1 is a transcription factor that is implicated in transforming growth factor-β/bone morphogenetic protein signaling and a repressor of E-cadherin and human telomerase reverse transcriptase. It is also involved in epithelial-mesenchymal transition and tumorigenesis. However, genetic and epigenetic alterations of SIP1 have not been fully elucidated in cancers. In this study, we investigated mutations and promoter hypermethylation of the SIP1 gene in human hepatocellular carcinomas.Methods: SIP1 expression was analyzed in HCC cell lines and primary tumors in comparison to normal and non-tumor liver tissues by using semi-quantitative RT-PCR, quantitative real-time RT-PCR and immunohistochemistry. Mutation and deletion screening of the SIP1 gene were performed by direct sequencing in HCC-derived cells. Restoration of SIP1 expression was sought by treating HCC cell lines with the DNA methyl transferase inhibitor, 5-AzaC, and the histone deacetylase inhibitor, TSA. SIP1 promoter methylation was analyzed by the combined bisulfite restriction analysis assay in in silico-predicted putative promoter and CpG island regions.Results: We found that the expression of SIP1 was completely lost or reduced in five of 14 (36%) HCC cell lines and 17 of 23 (74%) primary HCC tumors. Immunohistochemical analysis confirmed that SIP1 mRNA downregulation was associated with decreased expression of the SIP1 protein in HCC tissues (82.8%). No somatic mutation was observed in SIP1 exons in any of the 14 HCC cell lines. Combined treatment with DNA methyl transferase and histone deacetylase inhibitors synergistically restored SIP1 expression in SIP1-negative cell lines. Analysis of three putative gene regulatory regions revealed tumor-specific methylation in more than half of the HCC cases.Conclusions: Epigenetic mechanisms contribute significantly to the downregulation of SIP1 expression in HCC. This finding adds a new level of complexity to the role of SIP1 in hepatocarcinogenesis. © 2011 Acun et al; licensee BioMed Central Ltd.
Keywords
azacitidinebisulfite
DNA methyltransferase inhibitor
histone deacetylase inhibitor
messenger RNA
Smad interacting protein 1
transcription factor
trichostatin A
unclassified drug
DNA methyltransferase
histone deacetylase inhibitor
homeodomain protein
hydroxamic acid
repressor protein
trichostatin A
ZEB2 protein, human
article
cancer cell culture
cancer tissue
computer model
controlled study
CpG island
DNA methylation
down regulation
drug potentiation
epigenetics
exon
gene deletion
gene mutation
gene sequence
human
human tissue
immunohistochemistry
liver
liver carcinogenesis
liver cell carcinoma
major clinical study
primary tumor
promoter region
protein expression
restriction mapping
reverse transcription polymerase chain reaction
somatic mutation
adult
aged
down regulation
drug antagonism
drug effect
female
gene expression regulation
genetic transcription
genetics
liver cell carcinoma
liver tumor
male
metabolism
middle aged
molecular genetics
nucleotide sequence
pathology
promoter region
tumor cell line
Adult
Aged
Aged, 80 and over
Azacitidine
Base Sequence
Carcinoma, Hepatocellular
Cell Line, Tumor
DNA Methylation
DNA Modification Methylases
DNA Mutational Analysis
Down-Regulation
Female
Gene Expression Regulation, Neoplastic
Histone Deacetylase Inhibitors
Homeodomain Proteins
Humans
Hydroxamic Acids
Liver Neoplasms
Male
Middle Aged
Molecular Sequence Data
Promoter Regions, Genetic
Repressor Proteins
Restriction Mapping
Transcription, Genetic
Young Adult
Permalink
http://hdl.handle.net/11693/21891Published Version (Please cite this version)
http://dx.doi.org/10.1186/1471-2407-11-223Collections
Related items
Showing items related by title, author, creator and subject.
-
Quantification of SLIT-ROBO transcripts in hepatocellular carcinoma reveals two groups of genes with coordinate expression
Avci, M. E.; Konu, O.; Yagci, T. (BioMed Central, 2008)Background: SLIT-ROBO families of proteins mediate axon pathfinding and their expression is not solely confined to nervous system. Aberrant expression of SLIT-ROBO genes was repeatedly shown in a wide variety of cancers, ... -
Genetics and epigenetics of liver cancer
Özen, Çiğdem; Yıldız, Gökhan; Dağcan, Alper Tunga; Çevik, Dilek; Örs, Ayşegül; Keleş, Umut; Topel, Hande; Öztürk, Mehmet (Elsevier, 2013)Hepatocellular carcinoma (HCC) represents a major form of primary liver cancer in adults. Chronic infections with hepatitis B (HBV) and C (HCV) viruses and alcohol abuse are the major factors leading to HCC. This deadly ... -
A resampling-based meta-analysis for detection of differential gene expression in breast cancer
Gur-Dedeoglu, B.; Konu, O.; Kir, S.; Ozturk, A. R.; Bozkurt, B.; Ergul, G.; Yulug, I.G. (BioMed Central, 2008)Background: Accuracy in the diagnosis of breast cancer and classification of cancer subtypes has improved over the years with the development of well-established immunohistopathological criteria. More recently, diagnostic ...