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Ex vivo reversal of chemoresistance by tariquidar (XR9576)

Federica Di Nicolantonio1, Louise A Knight, Sharon Glaysher

  • 1Translational Oncology Research Centre, Department of Histopathology, Queen Alexandra Hospital, Portsmouth PO6 3LY, UK.

Anti-Cancer Drugs
|October 1, 2004
PubMed

Insights

Tariquidar, a P-glycoprotein (P-gp) inhibitor, effectively reverses chemotherapy resistance in solid tumors. Combining tariquidar with cytotoxic drugs like doxorubicin and paclitaxel shows significant activity against P-gp expressing cancers.

Area of Science:

  • Oncology
  • Pharmacology
  • Molecular Biology

Background:

  • P-glycoprotein (P-gp) mediates resistance to multiple anticancer drugs.
  • Tariquidar is a novel P-gp inhibitor with demonstrated efficacy in preclinical models.
  • Drug resistance remains a significant challenge in solid tumor treatment.

Purpose of the Study:

  • To evaluate the efficacy of tariquidar in combination with cytotoxic agents against solid tumors.
  • To assess the impact of tariquidar on drug resistance mediated by P-gp.
  • To determine the correlation between P-gp expression and tariquidar's activity.

Main Methods:

  • ATP-based chemosensitivity assay (ATP-TCA) used to test drug combinations.
  • 37 solid tumor samples evaluated for chemosensitivity.
  • Immunohistochemistry used to determine P-gp expression in 16 tumor samples.

Main Results:

  • Tariquidar significantly reduced IC90 values for doxorubicin, paclitaxel, and vinorelbine.
  • Chemotherapy resistance was reversed in 70% of doxorubicin-treated, 22% of paclitaxel-treated, and 35% of vinorelbine-treated samples.
  • Positive P-gp expression correlated with improved cytotoxic activity upon tariquidar addition.

Conclusions:

  • Tariquidar effectively overcomes P-gp-mediated resistance in various solid tumors.
  • Combination therapy with tariquidar and chemotherapy warrants clinical investigation.
  • Tariquidar holds promise for improving treatment outcomes in P-gp-positive solid tumors.

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