Hypermethylation of Cyclin D2 is associated with loss of mRNA expression and tumor development in prostate cancer.
D-type cyclins play a pivotal role in cell cycle regulation and their abnormal expression was associated with several human malignancies. To assess Cyclin D2 promoter methylation status and expression levels in prostate tissues, quantitative methylation-specific PCR and quantitative reverse transcription PCR assays were performed in a large series of prostate carcinomas, high-grade prostatic intraepithelial neoplasias (HGPIN), benign prostate hyperplasias (BPH), normal prostate tissue (NPT) samples, and prostate cancer (PCa) cell lines (before and after demethylating treatment). Methylation levels were correlated with mRNA expression levels and key clinicopathologic parameters. Cyclin D2 promoter methylation was found in 117/118 PCa, 38/38 HGPIN, 24/30 BPH, 11/11 NPT, and 4/4 cell lines. Methylation levels were significantly higher in PCa compared with HGPIN, NPT, and BPH (P<0.0001), correlating with tumor stage and Gleason score (r=0.29, P=0.0014; and r=0.32, P=0.0005, respectively). Conversely, Cyclin D2 mRNA levels were significantly lower in PCa (P<0.01) and a significant inverse correlation between Cyclin D2 methylation and expression levels was found in prostatic tissues (r=-0.61, P<0.000001). Demethylating treatment induced a substantial increase in Cyclin D2 mRNA in LNCaP cells whereas decreased levels were observed in DU-145 and PC-3 cells. We concluded that Cyclin D2 promoter methylation downregulates gene transcription and occurs with high frequency at low levels in normal, hyperplastic, and preneoplastic prostate tissues. Conversely, high Cyclin D2 methylation levels characterize invasive prostatic carcinoma, correlating with clinicopathologic features of tumor aggressiveness.
Henrique
Rui
R
Department of Pathology, Portuguese Oncology Institute, Porto, Rua Dr. Antonio Bernardino de Almeida, Porto, 4200-072, Portugal.
Costa
Vera Lúcia
VL
Cerveira
Nuno
N
Carvalho
André Lopes
AL
Hoque
Mohammad Obaidul
MO
Ribeiro
Franclim Ricardo
FR
Oliveira
Jorge
J
Teixeira
Manuel Rodrigues
MR
Sidransky
David
D
Jerónimo
Carmen
C
D000230:Adenocarcinoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D000328:Adult; D000368:Aged; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D056742:Cyclin D2; D016213:Cyclins / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation / Q000187:drug effects; D015254:DNA Modification Methylases / Q000037:antagonists & inhibitors; D000077209:Decitabine; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011401:Promoter Regions, Genetic; D011470:Prostatic Hyperplasia / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D019048:Prostatic Intraepithelial Neoplasia / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
C080336:CCND2 protein, human; D056742:Cyclin D2; D016213:Cyclins; D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D000077209:Decitabine; D015254:DNA Modification Methylases; D001374:Azacitidine