Molecular Targets for Methotrexate

Fan, Chinan C.; Henderson, Gary B.; Vitols, Κ.S.; Huennekens, F.M.

doi:10.1016/b978-0-08-024384-9.50030-0

Cited by 3 publications

(4 citation statements)

References 11 publications

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“…These and earlier studies from the authors laboratory (6) and others (5,7,29) utilizing alternative methods of size estimation suggested that L1210 cell RFT exists in the plasma membrane as a 43-46-kDa protein in a form with little or no core oligosaccharides attached (14). In the latter case, this was concluded from an experiment examining (14) the effect of N-glycanase on the migration of stained purified RFT during SDS-PAGE. We have extended these studies in greater detail to show that immunologically delineated RFT has no detectable N-or Olinked oligosaccharides attached.…”

Section: Discussionmentioning

confidence: 78%

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Ligand-directed Immunoaffinity Purification and Properties of the One-carbon, Reduced Folate Transporter

Chiao

Yang

Roy

et al. 1995

Journal of Biological Chemistry

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Almost complete purification (> 95%) of the 46-kDa murine, one-carbon, reduced folate transporter (RFT) at a recovery of 20% was obtained by ligand-directed immunoaffinity fractionation from transporter overproducing L1210/R83 cells. These cells were labeled with the N-hydroxysuccinimide ester of [3H]aminopterin (AMT), the isolated plasma membrane alkaline washed to remove nonintegral membrane proteins, detergent-solubilized, and RFT-separated on an anti-AMT antibody-protein G-Sepharose column followed by preparative SDS-polyacrylamide gel electrophoresis. Anti-RFT antibody, subsequently derived, differentially blotted (L1210/R83 >> L1210/0) a 46-kDa protein during SDS-polyacrylamide gel electrophoresis of plasma membrane from L1210/R83 and L1210 cells and in L1210/R83 cells after trichloroacetic acid precipitation. In contrast to that reported for human tumor cells, glycosidase treatment of RFT revealed no common N- or O-linked core oligosaccharides associated with this protein. The same 46-kDa protein at different relative levels was revealed in a Western blot of plasma membrane from other murine tumors. Blotting of plasma membrane from methotrexate resistant, transport defective L1210 cell variants exhibited wild-type levels of a less electrophoretically mobile RFT or greater levels of the same 46-kDa RFT which could not be affinity labeled with N-hydroxysuccinimide-[3H]AMT. The same antibody differentially blotted a 83-kDa plasma membrane protein from human HL-60 and CCRF-CEM cells with different levels of reduced folate transport and affinity labeling of RFT, verifying the conserved nature of this protein consistent with earlier functional studies.

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Section: Discussionmentioning

confidence: 78%

“…In a preliminary report (14), a method for purification of the RFT from L1210 cells was recently described. These workers utilized affinity purification by streptavidin "capture" of the transporter labeled with a biotinylated folate analogue to obtain microgram amounts of the transporter.…”

mentioning

confidence: 99%

Ligand-directed Immunoaffinity Purification and Properties of the One-carbon, Reduced Folate Transporter

Chiao

Yang

Roy

et al. 1995

Journal of Biological Chemistry

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“…[17][18][19] One of the most effective strategies involves coupling a specific ligand on the hydrophilic segment of polymeric micelles, which was recognizable by specific receptors overexpressed on the surface of the cancer cell cytomembrane. 25,26 It is selectively overexpressed on the apical membrane surface of certain epithelial cells, especially for brain, kidney, lung, and breast cancer cells. 25,26 It is selectively overexpressed on the apical membrane surface of certain epithelial cells, especially for brain, kidney, lung, and breast cancer cells.…”

Section: Introductionmentioning

confidence: 99%

“…[20][21][22][23][24] The folate receptor is a glycosylphosphatidylinositol-linked membrane glycoprotein of 38 kDa found in caveolae, which is involved in the process of cellular accumulation of folate molecules via the potocytosis mechanism. 25,26 It is selectively overexpressed on the apical membrane surface of certain epithelial cells, especially for brain, kidney, lung, and breast cancer cells. The overexpression of folate receptors on many cells is conducive to the employment of folate as a potential targeting molecule for various ligand/ antibody-directed cancer therapeutics to enhance the drug delivery efficiency through folate receptor-mediated endocytosis.…”

Section: Introductionmentioning

confidence: 99%

DOX-encapsulated intelligent PAA-g-PEG/PEG–Fa polymeric micelles for intensifying antitumor therapeutic effect via active-targeted tumor accumulation

et al. 2015

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Stimuli-responsive targeted polymeric micelles as drug delivery systems have recently attracted significant attention for the treatment of various cancers, which could improve delivery efficiency by tumor-specific recognition via active targeting strategies. In this research, DOX-incorporated bioreducible polymeric micelles based on PAA-g-PEG/PEG-Fa conjugated polymers were prepared and characterized as nanocarriers for promoting intracellular anti-tumor drug delivery efficiency via folate receptor-mediated endocytosis. The anti-proliferative activity on cancer cells, biodistribution, active-/ passive-targeting efficiency, tumor growth inhibition efficiency, and biological toxicity were evaluated in vitro and in vivo. The MTT assay demonstrated that the DOX-encapsulated active-targeting PAA-g-PEG/ PEG-Fa micelles had much greater growth inhibition effect against 4T1 and KB than passive-targeting micelles. These active-targeting micelles showed superior tumor accumulation and excellent tumor growth inhibition effect as revealed by the fluorescence optical imaging technique and tumor volume change investigation, as well as the survival study of the tumor-bearing Balb/c mice. Furthermore, the active targeting micelles greatly decreased the toxicity of DOX on the heart and other organs. These potential results encouraged us to further optimize the molecular structure to achieve more excellent targeted therapeutic effect.

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