title: Alteration of the methylation status of tumor-promoting genes decreases prostate cancer cell invasiveness and tumorigenesis in vitro and in vivo.
abstract: We tested the hypothesis that cell invasiveness and tumorigenesis are driven by hypomethylation of genes involved in tumor progression. Highly invasive human prostate cancer cells PC-3 were treated with either the methyl donor S-adenosylmethionine (SAM) or methyl DNA-binding domain protein 2 antisense oligonucleotide (MBD2-AS). Both treatments resulted in a dose- and time-dependent inhibition of key genes, such as urokinase-type plasminogen activator (uPA), matrix metalloproteinase-2 (MMP-2), and vascular endothelial growth factor expression to decrease tumor cell invasion in vitro. No change in the levels of expression of genes already known to be methylated in late-stage prostate cancer cells, such as glutathione S-transferase P1 and androgen receptor, was seen. Inoculation of PC-3 cells pretreated with SAM and MBD2-AS into the flank of male BALB/c nu/nu mice resulted in the development of tumors of significantly smaller volume compared with animals inoculated with PC-3 cells treated with vehicle alone or MBD2 scrambled oligonucleotide. Immunohistochemical analysis of tumors showed the ability of SAM and MBD2-AS to significantly decrease tumoral uPA and MMP-2 expression along with levels of angiogenesis and survival pathway signaling molecules. Bisulfite sequencing analysis of tumoral genomic DNA showed that inhibition of both uPA and MMP-2 expression was due to methylation of their 5' regulatory region. These studies support the hypothesis that DNA hypomethylation controls the activation of multiple tumor-promoting genes and provide valuable insight into developing novel therapeutic strategies against this common disease, which target the demethylation machinery.
authors.affiliation: Department of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Shukeir
authors.forename: Pouya
authors.initials: P
authors.lastname: Pakneshan
authors.forename: Gaoping
authors.initials: G
authors.lastname: Chen
authors.forename: Moshe
authors.initials: M
authors.lastname: Szyf
authors.forename: Shafaat A
authors.initials: SA
authors.lastname: Rabbani
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000235:genetics* / Q000473:pathology; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics; D015536:Down-Regulation; D015316:Genetic Therapy / Q000379:methods; D006801:Humans; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D009361:Neoplasm Invasiveness; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000628:therapy; D016376:Oligonucleotides, Antisense / Q000235:genetics; D010960:Plasminogen Activators / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics; D011471:Prostatic Neoplasms / Q000098:blood supply / Q000235:genetics* / Q000473:pathology / Q000628:therapy*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D012436:S-Adenosylmethionine / Q000494:pharmacology; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics; D023041:Xenograft Model Antitumor Assays
chemical_list: D004268:DNA-Binding Proteins; C489325:MBD2 protein, human; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D012436:S-Adenosylmethionine; D010960:Plasminogen Activators; D020778:Matrix Metalloproteinase 2