title: Increased levels of DNA methyltransferases are associated with the tumorigenic             capacity of prostate cancer cells.
abstract: DNA methylation might be the earliest somatic genome changes in prostate             cancer that also play an important role in the process of tumor invasion, growth             and metastasis. In recent years, several inhibitors of DNA methyltransferases             (DNMTis) have been developed and evaluated in pre-clinical models and in clinical             trials. While these compounds are effective in the treatment of hematological             conditions, clinical trials in solid tumors and in prostate cancer have shown             limited or no efficacy. This may be attributed to inappropriate dose regimens             leading to toxicity-related adverse events. As with other anti-target compounds,             one of the obstacles encountered with DNMTis in prostate cancer could be the inability             to select patients for the clinical studies as well as the inability to monitor             the efficacy of the drug if not the conclusion of the study. Primary cultures             derived from human prostatic tissues harvested from patients with benign prostatic             hyperplasia (BPH) and prostate cancer (PCa) as well as neoplastic and non-neoplastic             prostate cell lines were tested for DNMT expression/activity and to monitor azacitidine             molecular efficacy. We observed that in primary cultures the levels of DNMT activity             as well as the protein levels of DNMT1, DNMT3a and DNMT3b were higher in cultures             derived from PCa compared to BPH tissue samples and significantly higher in cultures             derived from PCa with Gleason scores ≥7 compared to those observed in cultures             derived from Gleason scores <7. In addition, DNMT activity as well as DNMT1,             DNMT3a and DNMT3b levels were higher in PCa cell lines compared to their non-neoplastic             counterparts. Although DNMT activity was higher in high tumorigenic/aggressive             PCa cell lines compared to low tumorigenic/aggressive cell lines, only the levels             of DNMT3a and DNMT3b were significantly higher in the first group of cells, suggesting             that DNMT1 activity is related to the transition to non-neoplastic versus neoplastic             phenotype whereas the de novo methylation enzymes were mainly related to progression.             Nevertheless, the comparison in the more aggressive PC3 cell derivatives (PC3-LN4             cells) also possessed higher levels of DNMT1 compared to PC3 and PC3M from which             these cells were derived. Collectively, our results confirm previous data on the             increased methylation in more aggressive tumors supporting the use of DNMTis in             advanced prostate cancer. In addition, since glutathione S-transferase-π (GSTP1)             was re-expressed or its protein levels were increased after treatment with non-toxic             azacitidine doses and since GSTP1 can easily be measured in patient sera, the             monitoring of this protein may aide in the evaluation of therapy in future clinical             trials.
authors.affiliation: Department of Biotechnological and Applied Clinical Science,                     Laboratory of Radiobiology, University of L'Aquila, L'Aquila, Italy.
authors.forename: Giovanni Luca
authors.initials: GL
authors.lastname: Gravina
authors.forename: Guido
authors.initials: G
authors.lastname: Ranieri
authors.forename: Paola
authors.initials: P
authors.lastname: Muzi
authors.forename: Francesco
authors.initials: F
authors.lastname: Marampon
authors.forename: Andrea
authors.initials: A
authors.lastname: Mancini
authors.forename: Boris
authors.initials: B
authors.lastname: Di Pasquale
authors.forename: Luigi
authors.initials: L
authors.lastname: Di Clemente
authors.forename: Vincenza
authors.initials: V
authors.lastname: Dolo
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: D'Alessandro
authors.forename: Claudio
authors.initials: C
authors.lastname: Festuccia
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D001374:Azacitidine / Q000494:pharmacology; D063646:Carcinogenesis / Q000378:metabolism*; D045744:Cell Line, Tumor; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism*; D000090205:DNA Methyltransferase 3A; D004847:Epithelial Cells / Q000201:enzymology; D015870:Gene Expression / Q000187:drug effects; D051549:Glutathione S-Transferase pi / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008297:Male; D010641:Phenotype; D011467:Prostate / Q000201:enzymology; D011470:Prostatic Hyperplasia / Q000201:enzymology; D011471:Prostatic Neoplasms / Q000201:enzymology*; D000097584:DNA Methyltransferase 3B
chemical_list: D000964:Antimetabolites, Antineoplastic; D001374:Azacitidine; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; D051549:Glutathione S-Transferase pi; D000097584:DNA Methyltransferase 3B; C000717967:DNMT3A protein, human; C000619380:DNMT1 protein, human; C496556:GSTP1 protein, human