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Modulation of gene expression and cell-cycle signaling pathways by the EGFR inhibitor gefitinib (Iressa) in rat urinary bladder cancer. Cancer Prev Res (Phila) 2012 Feb;5(2):248-59 PMID: 21982874

Pubmed ID

21982874

DOI

10.1158/1940-6207.CAPR-10-0363

Abstract

The epidermal growth factor receptor inhibitor Iressa has shown strong preventive efficacy in the N-butyl-N-(4-hydroxybutyl)-nitrosamine (OH-BBN) model of bladder cancer in the rat. To explore its antitumor mechanism, we implemented a systems biology approach to characterize gene expression and signaling pathways in rat urinary bladder cancers treated with Iressa. Eleven bladder tumors from control rats, seven tumors from rats treated with Iressa, and seven normal bladder epithelia were profiled by the Affymetrix Rat Exon 1.0 ST Arrays. We identified 713 downregulated and 641 upregulated genes in comparing bladder tumors versus normal bladder epithelia. In addition, 178 genes were downregulated and 96 genes were upregulated when comparing control tumors versus Iressa-treated tumors. Two coexpression modules that were significantly correlated with tumor status and treatment status were identified [r = 0.70, P = 2.80 × 10(-15) (bladder tumor vs. normal bladder epithelium) and r = 0.63, P = 2.00 × 10(-42) (Iressa-treated tumor vs. control tumor), respectively]. Both tumor module and treatment module were enriched for genes involved in cell-cycle processes. Twenty-four and twenty-one highly connected hub genes likely to be key drivers in cell cycle were identified in the tumor module and treatment module, respectively. Analysis of microRNA genes on the array chips showed that tumor module and treatment module were significantly associated with expression levels of let-7c (r = 0.54, P = 3.70 × 10(-8) and r = 0.73, P = 1.50 × 10(-65), respectively). These results suggest that let-7c downregulation and its regulated cell-cycle pathway may play an integral role in governing bladder tumor suppression or collaborative oncogenesis and that Iressa exhibits its preventive efficacy on bladder tumorigenesis by upregulating let-7 and inhibiting the cell cycle. Cell culture study confirmed that the increased expression of let-7c decreases Iressa-treated bladder tumor cell growth. The identified hub genes may also serve as pharmacodynamic or efficacy biomarkers in clinical trials of chemoprevention in human bladder cancer.

Author List

Lu Y, Liu P, Van den Bergh F, Zellmer V, James M, Wen W, Grubbs CJ, Lubet RA, You M

Authors

Michael James PhD Assistant Professor in the Surgery department at Medical College of Wisconsin
Pengyuan Liu PhD Adjunct Associate Professor in the Physiology department at Medical College of Wisconsin
Ming You MD, PhD Associate Provost, Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin




Scopus

2-s2.0-84863237623   12 Citations

MESH terms used to index this publication - Major topics in bold

Animals
Antineoplastic Agents
Biomarkers, Tumor
Blotting, Western
Cell Cycle
Cell Proliferation
ErbB Receptors
Female
Gene Expression Profiling
Gene Expression Regulation, Neoplastic
MicroRNAs
Oligonucleotide Array Sequence Analysis
Quinazolines
RNA, Messenger
Rats
Rats, Inbred F344
Real-Time Polymerase Chain Reaction
Signal Transduction
Urinary Bladder Neoplasms
jenkins-FCD Prod-353 9ccd8489072cb19f5b9f808bb23ed672c582f41e