S-Space College of Medicine/School of Medicine (의과대학/대학원) Orthopedic Surgery (정형외과학전공) Journal Papers (저널논문_정형외과학전공)
Quantitative correlation between promoter methylation and messenger RNA levels of the reduced folate carrier
- Issue Date
- BioMed Central
- BMC Cancer 8:124-132
- Antineoplastic Agents/administration & dosage ; Breast Neoplasms/drug therapy/enzymology/genetics/pathology ; Cell Line, Tumor ; Down-Regulation ; Drug Resistance, Neoplasm/drug effects ; Drug Therapy ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Membrane Transport Proteins/*biosynthesis/*genetics ; Methotrexate/administration & dosage ; Osteosarcoma/drug therapy/enzymology/genetics/pathology ; RNA, Messenger/biosynthesis/*genetics ; DNA Methylation ; Promoter Regions, Genetic
- BACKGROUND: Methotrexate (MTX) uptake is mediated by the reduced folate carrier (RFC). Defective drug uptake in association with decreased RFC expression is a common mechanism of MTX resistance in many tumor types. Heavy promoter methylation was previously identified as a basis for the complete silencing of RFC in MDA-MB-231 breast cancer cells, its role and prevalence in RFC transcription regulation are, however, not widely studied. METHODS: In the current study, RFC promoter methylation was assessed using methylation specific PCR in a panel of malignant cell lines (n = 8), including MDA-MB-231, and M805, a MTX resistant cell line directly established from the specimen of a patient with malignant fibrohistocytoma, whom received multiple doses of MTX. A quantitative approach of real-time PCR for measuring the extent of RFC promoter methylation was developed, and was validated by direct bisulfite genomic sequencing. RFC mRNA levels were determined by quantitative real-time RT-PCR and were related to the extent of promoter methylation in these cell lines. RESULTS: A partial promoter methylation and RFC mRNA down-regulation were observed in M805. Using the quantitative approach, a reverse correlation (correlation coefficient = -0.59, p < 0.05) was identified between the promoter methylation and RFC mRNA levels in this a panel of malignant cell lines. CONCLUSION: This study further suggests that promoter methylation is a potential basis for MTX resistance. The quantitative correlation identified in this study implies that promoter methylation is possibly a mechanism involved in the fine regulation of RFC transcription.
- 1471-2407 (Electronic)