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Series GSE9412 Query DataSets for GSE9412
Status Public on Dec 30, 2007
Title Transcriptional regulation of aldo-keto reductase 1C1 in human colon cancer cells resistant to methotrexate
Organism Homo sapiens
Experiment type Expression profiling by array
Summary The abstract of the associated publication (Selga E, Noé V, Ciudad CJ. Biochemical Pharmacology, 2008) is the following:

While studying differentially expressed genes between sensitive and 10-5 M Methotrexate (MTX) resistant HT29 human colon cancer cells, we identified some members of the aldo-keto reductase (AKR) superfamily. The study was followed with the member AKR1C1 (EC, validating its increase in mRNA and protein levels in MTX resistant cells. The genomic content for AKR1C1 remained unchanged between sensitive and resistant cells, thereby excluding a mechanism of AKR1C1 gene amplification. Thus, we cloned the AKR1C1 human promoter and performed luciferase experiments that revealed a transcriptional regulation of the gene in the resistant cells. Computational studies showed a putative binding site for the transcription factor Sp1. The co-transfection of Sp1 or Sp3 with different constructs of AKR1C1 promoter deletions, including and excluding the proximal GC-box, demonstrated a key role for these factors in regulating AKR1C1 transcriptional activity. Gel-shift assays revealed an increase in Sp1 and Sp3 binding in resistant compared to sensitive cells, without differences in Sp1 protein levels. Dephosphorylation of the extracts coincided with a decrease in Sp1 binding, which is consistent with a process of regulation of Sp1 by phosphorylation. We also investigated the possible relationship between AKR1C1 expression and MTX action. Overexpression of AKR1C1 counteracted the S-phase accumulation of cells and apoptosis caused by MTX treatment. This suggests a role of AKR1C1 in cell proliferation. Finally, overexpression of AKR1C1 in MTX sensitive HT29 cells conferred resistance to the chemotherapeutic agent and silencing of AKR1C1 by means of iRNA technology sensitized the cells to MTX.
Keywords: DHFR, Methotrexate, drug-resistance
Overall design Two cell lines are compared in the study, which are HT29 colon cancer cells sensitive to methotrexate and HT29 cells resistant to 10e-5M methotrexate. Six samples are provided, which correspond to triplicates of each cell line. The samples provided were subsequently normalyzed and analyzed using the specific software GeneSpring GX 7.3.1
Contributor(s) Selga E, Ciudad CJ, Noé V
Citation(s) 17945194
Submission date Oct 23, 2007
Last update date Dec 06, 2018
Contact name Carlos J Ciudad
Phone +34-93-403-4455
Organization name University of Barcelona
Department Biochemistry and Molecular Biology
Lab School of Pharmacy
Street address Av. Juan XXIII-27
City Barcelona
State/province Barcelona
ZIP/Postal code 08028
Country Spain
Platforms (1)
GPL571 [HG-U133A_2] Affymetrix Human Genome U133A 2.0 Array
Samples (6)
GSM239309 HT29 sensitive cells replicate 1
GSM239310 HT29 sensitive replicate 2
GSM239311 HT29 sensitive replicate 3
BioProject PRJNA103145

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Supplementary file Size Download File type/resource
GSE9412_RAW.tar 18.3 Mb (http)(custom) TAR (of CEL)
Processed data included within Sample table

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