The Gene Expression Profiles of Medulloblastoma Cell Lines Resistant to Preactivated Cyclophosphamide
Authors: Bacolod, M. D.; Lin, S. M.; Johnson, S. P.; Bullock, N. S.; Colvin, M.; Bigner, D. D.; Friedman, H. S.
Source: Current Cancer Drug Targets, Volume 8, Number 3, May 2008 , pp. 172-179(8)
Publisher: Bentham Science Publishers
Abstract:
The total expression profiles of two medulloblastoma cell lines resistant to the preactivated form of cyclophosphamide (4-hydroperoxycyclophosphamide, 4-HC) were examined using the Affymetrix GeneChip U133A array. Our primary objective was to look for possible genes, other than the well-studied aldehyde dehydrogenases (ALDH) that may be involved in cyclophosphamide (CP) resistance in medulloblastomas. We present here the lists of the most highly upregulated [30 for D341 MED (4-HCR); 20 for D283 MED (4-HCR)] and downregulated [19 for D341 MED (4-HCR); 15 for D283 MED (4-HCR)] genes which may be involved in conferring CP-resistance to the two medullobalstoma cell lines. The lists of genes from the two sublines almost had no overlap, suggesting different mechanisms of CP-resistance. One of the most noteworthy upregulated gene is TAP1 [ 90-fold increase in D341 MED (4-HCR) relative to D341 MED ]. TAP1, a protein belonging to the ABC transporter family is normally involved in major histocompatibility class I (MHC I) antigen processing. This suggests the possible role of multidrug resistance (MDR), albeit atypical (which means it does not involve the usual MDR1 and MRP glycoproteins), in medulloblastoma's CP-resistance. Apart from TAP1, a number of other genes involved in MHC1 processing were upregulated in D341 MED (4HCR). D341 MED (4-HCR) also had a 20-fold increase in the expression of the aldo-keto reductase gene, AKR1B10, which may deactivate the reactive cyclophosphamide metabolite, aldophosphamide. For D283 MED (4-HCR), the most notable increase in expression is that of ALDH1B1, a member of the aldehyde dehydrogenase (ALDH) family of proteins.Keywords: Cyclophosphamide; drug resistance; medulloblastoma; brain tumor; oxazaphosphorine; aldehyde dehydrogenase; microarray; aldo-keto reductase
Document Type: Research article
DOI: http://dx.doi.org/10.2174/156800908784293631
Publication date: 2008-05-01
- Current Cancer Drug Targets aims to cover all the latest and outstanding developments on the medicinal chemistry, pharmacology, molecular biology, genomics and biochemistry of contemporary molecular drug targets involved in cancer, e.g. disease specific proteins, receptors, enzymes, genes.
Each issue of the journal contains a series of timely in-depth reviews written by leaders in the field covering a range of current topics on drug targets involved in cancer.
As the discovery, identification, characterization and validation of novel human drug targets for anti-cancer drug discovery continues to grow; this journal has become essential reading for all pharmaceutical scientists involved in drug discovery and development.
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- In this Subject: Oncology , Pharmacology
- By this author: Bacolod, M. D. ; Lin, S. M. ; Johnson, S. P. ; Bullock, N. S. ; Colvin, M. ; Bigner, D. D. ; Friedman, H. S.

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