title: A proteomics-based translational approach reveals an antifolate resistance inherent in human plasma derived from blood donation.
abstract: The inhibition of dihydrofolate reductase (DHFR) by antifolates is a common practice both in cell culture and in chemotherapy. Surprisingly, antifolate resistance was also observed in cultured murine myeloma cells (SP2/0) in the presence of human plasma (HP); thus, we used a proteomic approach to identify novel plasma biomarker(s) for this condition. In contrast to the in vitro antifolate response, metabolic enzymes and translation machinery proteins were found to be up-regulated in the presence of HP. The antifolate resistance inherent in HP may be explained by a simultaneous promotion of cell proliferation and the maintenance of DNA integrity. Furthermore, the factor(s) was found to be extrinsic, heat stable and very small in size. Adenine, a supplemented additive in erythrocyte preservation, was subsequently identified as the contributing factor and exogenous addition in cultures reversed the cytotoxicity induced by antifolates. Importantly, adenine-containing blood components, which may provide enhanced survival to otherwise sensitive antifolate-targeted cells, showed a dose-dependent adverse effect in transfusion recipients receiving antifolate (methotrexate) medications. These findings not only highlight a previously unnoticed role of adenine, but also emphasize a novel mechanistic link between transfusion and subsequently reduced survival in patients taking methotrexate.
authors: Department of Microbiology and Immunology, National Chiayi University, Chiayi, Taiwan.
authors: Li-Te
authors: LT
authors: Chin
authors: Pei-Ru
authors: PR
authors: Huang
authors: Kuang-Yu
authors: KY
authors: Hu
authors: Nai-Kuei
authors: NK
authors: Huang
authors: Cheng-Di
authors: CD
authors: Chiu
authors: Ai-Ling
authors: AL
authors: Hour
authors: Hao-Ai
authors: HA
authors: Shui
authors: Chi-Hong
authors: CH
authors: Chu
authors: Han-Min
authors: HM
authors: Chen
mesh_terms: D000225:Adenine / Q000494:pharmacology; D000630:Aminopterin; D000818:Animals; D001793:Blood Preservation; D001798:Blood Proteins / Q000378:metabolism / Q000494:pharmacology*; D001803:Blood Transfusion; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D016000:Cluster Analysis; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance / Q000187:drug effects*; D004355:Drug Stability; D015180:Electrophoresis, Gel, Two-Dimensional; D005493:Folic Acid Antagonists / Q000494:pharmacology*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008727:Methotrexate; D051379:Mice; D011310:Preservatives, Pharmaceutical; D040901:Proteomics / Q000379:methods*; D012189:Retrospective Studies; D049490:Systems Biology / Q000379:methods*; D015854:Up-Regulation
chemical_list: D001798:Blood Proteins; D005493:Folic Acid Antagonists; D011310:Preservatives, Pharmaceutical; D000225:Adenine; D000630:Aminopterin; D008727:Methotrexate