Specific tumour-associated methylation in normal human term placenta and first-trimester cytotrophoblasts.
Human placentation displays many similarities with tumourigenesis, including rapid cell division, migration and invasion, overlapping gene expression profiles and escape from immune detection. Recent data have identified promoter methylation in the Ras association factor and adenomatous polyposis coli tumour suppressor genes as part of this process. However, the extent of tumour-associated methylation in the placenta remains unclear. Using whole genome methylation data as a starting point, we have examined this phenomenon in placental tissue. We found no evidence for methylation of the majority of common tumour suppressor genes in term placentas, but identified methylation in several genes previously described in some human tumours. Notably, promoter methylation of four independent negative regulators of Wnt signalling has now been identified in human placental tissue and purified trophoblasts. Methylation is present in baboon, but not in mouse placentas. This supports a role for elevated Wnt signalling in primate trophoblast invasiveness and placentation. Examination of invasive choriocarcinoma cell lines revealed altered methylation patterns consistent with a role of methylation change in gestational trophoblastic disease. This distinct pattern of tumour-associated methylation implicates a coordinated series of epigenetic silencing events, similar to those associated with some tumours, in the distinct features of normal human placental invasion and function.
Novakovic
B
B
Developmental Epigenetics Research, Murdoch Children's Research Institute, Royal Children's Hospital, VIC 3052, Australia.
Rakyan
V
V
Ng
H K
HK
Manuelpillai
U
U
Dewi
C
C
Wong
N C
NC
Morley
R
R
Down
T
T
Beck
S
S
Craig
J M
JM
Saffery
R
R
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D019175:DNA Methylation; D004268:DNA-Binding Proteins; D051765:Early Growth Response Transcription Factors / Q000235:genetics; D005260:Female; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D009369:Neoplasms / Q000235:genetics / Q000473:pathology; D010215:Papio; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012097:Repressor Proteins / Q000235:genetics; D014327:Trophoblasts / Q000166:cytology / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000235:genetics; D000094742:Secreted Frizzled-Related Proteins
D051792:Basic Helix-Loop-Helix Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D051765:Early Growth Response Transcription Factors; D018960:Hyaluronan Receptors; D008565:Membrane Proteins; D012097:Repressor Proteins; D025521:Tumor Suppressor Proteins; C111028:EGR4 protein, human; C425208:PCLAF protein, human; C411762:RASSF1 protein, human; C109618:SFRP2 protein, human; D000094742:Secreted Frizzled-Related Proteins; C491094:SIM1 protein, human