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Drug-Induced Senescence in Liver Cells Promotes M2 Macrophage Polarization: Implications for Tyrosine Kinase Inhibitor-Associated Hepatotoxicity
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Lapatinib antagonizes multidrug resistance-associated protein 1-mediated multidrug resistance by inhibiting its

Shao-lin Ma1, Ya-peng Hu1, Fang Wang1

  • 1Collaborative Innovation Center for Cancer Medicine, State Key Laboratory of Oncology in South China, Cancer Center of Sun Yat-Sen University, Guangzhou, China.

Molecular Medicine (Cambridge, Mass.)
|August 9, 2014
PubMed

Insights

Lapatinib enhances chemotherapy efficacy in MRP1-overexpressing cancers by inhibiting the MRP1 transporter. This tyrosine kinase inhibitor improves drug accumulation without affecting AKT or ERK1/2 phosphorylation, offering new clinical possibilities.

Area of Science:

  • Oncology
  • Pharmacology
  • Molecular Biology

Background:

  • Lapatinib is a tyrosine kinase inhibitor for HER2-positive breast cancer.
  • ATP-binding cassette (ABC) transporters like ABCB1 and ABCG2 drive multidrug resistance (MDR).
  • The role of other efflux pumps, including MRP1, in lapatinib's efficacy is less understood.

Purpose of the Study:

  • To investigate lapatinib's impact on multidrug resistance-associated protein 1 (MRP1) and other drug efflux pumps.
  • To determine if lapatinib can overcome resistance mediated by MRP1, MRP2, MRP4, and LRP.
  • To elucidate the mechanism by which lapatinib affects MRP1 function.

Main Methods:

  • In vitro and in vivo studies using MRP1-overexpressing cells.
  • Assessing lapatinib's effect on the efficacy of conventional chemotherapeutic agents.
  • Measuring the intracellular accumulation of rhodamine 123 and doxorubicin.
  • Analyzing protein and mRNA expression levels of MRP1.
  • Evaluating AKT and ERK1/2 phosphorylation levels.

Main Results:

  • Lapatinib enhanced chemotherapeutic efficacy in MRP1-overexpressing cells but not in cells overexpressing MRP2, MRP4, or LRP.
  • Lapatinib increased intracellular accumulation of rhodamine 123 and doxorubicin in MRP1-overexpressing cells.
  • Lapatinib did not alter MRP1 protein or mRNA expression, nor AKT/ERK1/2 phosphorylation.

Conclusions:

  • Lapatinib inhibits MRP1 transport function, enhancing chemotherapy efficacy in MRP1-overexpressing cancers.
  • This mechanism operates independently of changes in AKT or ERK1/2 phosphorylation.
  • Findings support clinical trials combining lapatinib with conventional agents for MRP1-overexpressing cancers.

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