Retrotransposon hypomethylation in melanoma and expression of a placenta-specific gene.
In the human placenta, DNA hypomethylation permits the expression of retrotransposon-derived genes that are normally silenced by methylation in somatic tissues. We previously identified hypomethylation of a retrotransposon-derived transcript of the voltage-gated potassium channel gene KCNH5 that is expressed only in human placenta. However, an RNA sequence from this placental-specific transcript has been reported in melanoma. This study examined the promoter methylation and expression of the retrotransposon-derived KCNH5 transcript in 25 melanoma cell lines to determine whether the acquisition of 'placental' epigenetic marks is a feature of melanoma. Methylation and gene expression analysis revealed hypomethylation of this retrotransposon in melanoma cell lines, particularly in those samples that express the placental KCNH5 transcript. Therefore we propose that hypomethylation of the placental-specific KCNH5 promoter is frequently associated with KCNH5 expression in melanoma cells. Our findings show that melanoma can develop hypomethylation of a retrotransposon-derived gene; a characteristic notably shared with the normal placenta.
Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand; Gravida: National Centre for Growth and Development, Auckland, New Zealand.
Erin C
EC
Macaulay
Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand; Gravida: National Centre for Growth and Development, Auckland, New Zealand.
Hester E
HE
Roberts
Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
Xi
X
Cheng
Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
Aaron R
AR
Jeffs
Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand.
Bruce C
BC
Baguley
Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand; Gravida: National Centre for Growth and Development, Auckland, New Zealand.
Ian M
IM
Morison
D045744:Cell Line, Tumor; D019175:DNA Methylation / Q000235:genetics*; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008545:Melanoma / Q000235:genetics / Q000378:metabolism; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011401:Promoter Regions, Genetic / Q000235:genetics; D018626:Retroelements / Q000235:genetics*
D051638:Ether-A-Go-Go Potassium Channels; C485729:KCNH5 protein, human; D018626:Retroelements