An integrative genomic analysis revealed the relevance of microRNA and gene expression for drug-resistance in human breast cancer cells

Mol Cancer. 2011 Nov 3;10:135. doi: 10.1186/1476-4598-10-135.


Background: Acquisition of drug-resistance in cancer has led to treatment failure, however, their mechanisms have not been clarified yet. Recent observations indicated that aberrant expressed microRNA (miRNA) caused by chromosomal alterations play a critical role in the initiation and progression of cancer. Here, we performed an integrated genomic analysis combined with array-based comparative hybridization, miRNA, and gene expression microarray to elucidate the mechanism of drug-resistance.

Results: Through genomic approaches in MCF7-ADR; a drug-resistant breast cancer cell line, our results reflect the unique features of drug-resistance, including MDR1 overexpression via genomic amplification and miRNA-mediated TP53INP1 down-regulation. Using a gain of function study with 12 miRNAs whose expressions were down-regulated and genome regions were deleted, we show that miR-505 is a novel tumor suppressive miRNA and inhibits cell proliferation by inducing apoptosis. We also find that Akt3, correlate inversely with miR-505, modulates drug sensitivity in MCF7-ADR.

Conclusion: These findings indicate that various genes and miRNAs orchestrate to temper the drug-resistance in cancer cells, and thus acquisition of drug-resistance is intricately controlled by genomic status, gene and miRNA expression changes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis
  • Breast Neoplasms / drug therapy
  • Breast Neoplasms / genetics*
  • Cell Line, Tumor
  • Cell Proliferation
  • Docetaxel
  • Down-Regulation
  • Drug Resistance, Neoplasm / genetics*
  • Female
  • Gene Expression Regulation, Neoplastic*
  • Genome, Human
  • Humans
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism
  • Microarray Analysis
  • Proto-Oncogene Proteins c-akt / genetics
  • Proto-Oncogene Proteins c-akt / metabolism
  • Taxoids / pharmacology
  • Taxoids / therapeutic use


  • MIRN505 microRNA, human
  • MicroRNAs
  • Taxoids
  • Docetaxel
  • AKT3 protein, human
  • Proto-Oncogene Proteins c-akt