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Pharmacogenomic identification of novel determinants of response to chemotherapy in colon cancer

John Boyer1, Wendy L Allen, Estelle G McLean

  • 1Department of Oncology, Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland.

Cancer Research
|March 3, 2006
PubMed

Insights

This study identifies gene expression patterns in colorectal cancer cells resistant to 5-fluorouracil (5-FU) and oxaliplatin. These gene signatures may predict patient response to chemotherapy and serve as therapeutic targets.

Area of Science:

  • Genomics
  • Cancer Biology
  • Pharmacogenomics

Background:

  • Colorectal cancer (CRC) treatment often involves 5-fluorouracil (5-FU) and oxaliplatin.
  • Acquired resistance to these chemotherapeutic agents is a significant clinical challenge.
  • Identifying molecular markers of drug sensitivity and resistance is crucial for personalized CRC therapy.

Purpose of the Study:

  • To identify gene expression signatures associated with 5-FU and oxaliplatin resistance in HCT116 colorectal cancer cells.
  • To validate these signatures using quantitative real-time reverse transcription-PCR (RT-PCR).
  • To explore the functional role of specific identified genes in drug response.

Main Methods:

  • DNA microarray analysis to profile gene expression in drug-resistant and drug-sensitive HCT116 cells.
  • Bioinformatic analysis to identify differentially expressed genes.
  • Real-time RT-PCR to validate microarray findings.
  • Functional analysis of selected genes (PDF, calretinin, SSAT).

Main Results:

  • Identified distinct sets of genes constitutively dysregulated in drug-resistant cells and transiently altered upon acute drug exposure.
  • Validated microarray data with high concordance for gene expression trends (>82% for oxaliplatin, >85% for 5-FU).
  • Demonstrated strong correlations between microarray and RT-PCR measurements (R² > 0.63).
  • Functional analysis confirmed prostate-derived factor (PDF), calretinin, and spermidine/spermine N(1)-acetyl transferase (SSAT) as novel regulators of cytotoxic drug response.

Conclusions:

  • A novel microarray-based approach effectively identifies gene expression signatures related to drug response in colorectal cancer.
  • These identified genes may serve as predictive biomarkers for 5-FU and oxaliplatin sensitivity.
  • The findings highlight potential novel therapeutic targets for overcoming chemoresistance in CRC.

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