Polymorphisms and methylation of the reduced folate carrier in osteosarcoma.
High-dose methotrexate is a standard component in the treatment of osteogenic sarcoma. Impaired methotrexate uptake associated with decreased reduced folate carrier expression is a common mechanism of methotrexate resistance in osteogenic sarcoma samples. We investigated whether promoter methylation and polymorphisms in the 3' untranslated region are involved in regulating reduced folate carrier expression. In a cohort of 66 osteogenic sarcoma specimens, quantitative methylation-specific polymerase chain reaction and single-strand conformation polymorphism were performed. We found detectable levels of promoter methylation in 84.3% of samples. When related to the reduced folate carrier mRNA levels, a trend was observed that reduced folate carrier expression is lower in samples (median, 0.7) with greater than 10% DNA methylation as compared with those (median, 2.3) with less than 10% DNA methylation. The heterozygous polymorphisms of 2582 T/G and 2617C/T in the 3' untranslated region showed reduced folate carrier expression (median, 0.9) as compared with the wild-type 2582T and 2617C (median, 4.2). The data suggest promoter methylation and polymorphisms in the 3' untranslated region of the reduced folate carrier may be involved in its transcriptional regulation in osteogenic sarcoma. Further study is required to confirm this finding.
Department of Pediatrics and Molecular Pharmacology, The Albert Einstein College of Medicine, The Children's Hospital at Montefiore, 3415 Bainbridge Avenue, Rosenthal 3rd Floor, Bronx, NY 10467, USA.
Rui
R
Yang
Jing
J
Qin
Bang H
BH
Hoang
John H
JH
Healey
Richard
R
Gorlick
D000293:Adolescent; D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D019175:DNA Methylation; D005260:Female; D005492:Folic Acid / Q000235:genetics*; D006801:Humans; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics*; D008875:Middle Aged; D012516:Osteosarcoma / Q000235:genetics*; D018807:Polymorphism, Single-Stranded Conformational; D011401:Promoter Regions, Genetic / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D058978:Reduced Folate Carrier Protein; D014158:Transcription, Genetic / Q000502:physiology
D026901:Membrane Transport Proteins; D012333:RNA, Messenger; D058978:Reduced Folate Carrier Protein; C548699:SLC19A1 protein, human; D005492:Folic Acid