Aberrant methylation of the vascular endothelial growth factor receptor‐1 gene in prostate cancer

Abstract

Transcriptional silencing of cancer-related genes by DNA methylation is observed in various cancers. To identify genes controlled by methylation in prostate cancer, we used cDNA microarray analysis to investigate gene expression in prostate cancer cell lines LNCaP and DU145 treated with a methyltransferase inhibitor alone or together with a histone deacetylase inhibitor. We detected significant changes (3.4-5.7%) in gene expression in prostate cancer cell lines with the drug treatments. Among the affected genes, that for the vascular endothelial growth factor receptor 1 (VEGFR-1) was re-expressed in LNCaP and DU145 after the drug treatments. Bisulfite sequencing revealed the promoter and exon 1 of the VEGFR-1 to be hypermethylated in the cell lines. These results support the idea that methylation is associ- rostate cancer is not as commonly diagnosed in Japanese as in Caucasians or African-Americans, but the number of cases is increasing every year. Genetic alterations, such as point mutations, loss of heterozygosity, and homozygous deletions in many tumor suppressor genes, are associated with carcinogenesis.1) Many studies have provided evidence of such genetic alterations in prostate cancers.2) More recently, it has also been reported that inactivation of tumor suppressor genes by epigenetic promoter methylation plays an important role in carcinogenesis and tumor progression.3) DNA methylation, especially in CpG-rich 5′ regions, inhibits transcription by interfering with the initiation or by reducing the binding affinity of sequence-specific transcription factors. 4)In prostate cancer, inactivation by aberrant methylation has been reported for many genes, such as RARβ2, GSTP1, E-cadherin and RASSF1A. [5][6][7][8][9] Restriction landmark genomic scanning (RLGS), 9) methylated CpG island amplification (MCA)/ representational difference analysis (RDA), 10) methylation-sensitive (MS)/RDA, 11) and differential methylation hybridization (DMH) 12) have been employed to find genes whose expression is regulated by DNA methylation.To identify cancer-related genes controlled by epigenetic alteration in prostate cancer, we have performed screening by cDNA microarray analysis in prostate cancer cell lines treated with a methyltransferase or/and a histone deacetylase inhibitor. We detected significant re-expression of the vascular endothelial growth factor receptor 1 (VEGFR-1) gene in cells treated with drugs. VEGFR-1, also called Flt-1, is a tyrosine kinase receptor for VEGF which plays an important role in tumor angiogenesis and growth. 13,14) Several studies have pointed to altered expression and function of VEGF or its receptor (VEGFR-1, -2) in prostate cancer. In this study, we analyzed the methylation status of the 5′ region of VEGFR-1 in prostate cancer cell lines and primary prostate samples. Materials and MethodsCell lines and primary prostatic samples. Prostate cancer cell lines, LNCaP, DU145 and PC-3, were obtained from the American Type Tissue Culture Collection (Rockville, MD) and cultured in RPMI 1640 medium s...

The expression of VEGF receptor genes is concurrently influenced by epigenetic gene silencing of the genes and VEGF activation

“…A previous study suggested promoter hypermethylation of Flt-1 as a possible modulating factor for Flt-1 expression in prostatic cancer. 17 However, the relationship between promoter methylation and expression of VEGF, Flt-1 and KDR had not been well elucidated in other cancers. The present negative correlation between promoter hypermethylation and VEGFR gene expression supports a model of epigenetic control of VEGFR gene expression.…”

“…16 In a previous study, aberrant promoter methylation of VEGFR1, Flt-1, was reported in prostatic cancer. 17 However, the promoter methylation status of VEGF and the VEGFR genes has not been well elucidated in other cancer types. In the present study, we evaluated the promoter DNA methylation status and related expression levels of VEGF and the VEGFR genes in different cancer cell lines and primary solid cancers.…”

Tumour-stroma interactions between metastatic prostate cancer cells and fibroblasts

“…Moreover, an autocrine function of VEGF on prostate cancer cell proliferation has been suggested by the demonstration of the high affinity receptors VEGFR-1 and VEGFR-2 on prostate cancer cells (74,75). VEGFR-1 has been found to be slightly expressed in PC-3 but not expressed in LNCaP and DU-145 cells (76).…”

Epigenetic DNA-methylation regulation of genes coding for lipid raft-associated components: A role for raft proteins in cell transformation and cancer progression (Review)

“…We now know that VHL, VEGF and VEGF-R promoter activity is under the direct regulation of DNA-methylation (1,38,39,76). Ras oncogene induces a general demethylase activity in ras-transfected cells (77), promoting expression of many genes.…”