title: Intrinsic cisplatin resistance in lung and ovarian cancer cells propagating in medium acutely depleted of folate.
abstract: Many tumors develop intrinsic and/or acquired resistance to cisplatin. The purpose of the present study was to examine the influence of acute extracellular folate depletion prior to cisplatin treatment on the development of intrinsic cisplatin resistance. Lung and ovarian cancer cells were propagated in medium acutely depleted of folate and subsequently treated with cisplatin. The IC50 level for cisplatin, cell viability, cell proliferation, and global DNA methylation were determined. Gene expression profiling was performed using the Atlas Cancer 1.2 Array. Acute extracellular folate depletion resulted in the development of intrinsic cisplatin resistance. Cells propagating in medium acutely depleted of folate had a survival advantage compared to control cells when exposed to cisplatin, and thymidine supplementation did not reverse the intrinsic cisplatin resistance. cDNA microarray analysis revealed some novel genes associated with the development of intrinsic cisplatin resistance. Our report is the first to demonstrate that acute extracellular folate depletion results in intrinsic cisplatin resistance. If these results are confirmed by in vivo human studies, it would suggest that the folate status of the recipient of cisplatin might have an impact on response to that chemotherapeutic agent.
authors.affiliation: National Cancer Institute, Division of Cancer Prevention, Bethesda, MD 20892, USA.
authors.forename: Martin A
authors.initials: MA
authors.lastname: Whiteside
authors.forename: Chandrika J
authors.initials: CJ
authors.lastname: Piyathilake
authors.forename: Tamara M
authors.initials: TM
authors.lastname: Bushell
authors.forename: Gary L
authors.initials: GL
authors.lastname: Johanning
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology*; D003470:Culture Media / Q000737:chemistry; D019175:DNA Methylation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm; D005260:Female; D005492:Folic Acid / Q000494:pharmacology*; D005494:Folic Acid Deficiency; D020869:Gene Expression Profiling; D006801:Humans; D020128:Inhibitory Concentration 50; D008175:Lung Neoplasms / Q000188:drug therapy*; D046228:Microarray Analysis; D010051:Ovarian Neoplasms / Q000188:drug therapy*
chemical_list: D000970:Antineoplastic Agents; D003470:Culture Media; D005492:Folic Acid; D002945:Cisplatin