R-verapamil decreases anti-estrogen resistance in a breast cancer model

Anticancer Res. 1991 Mar-Apr;11(2):809-11.

Abstract

Drug resistance eventually limits the effectiveness of antiestrogens in breast cancer treatment. Pharmacological reversal of this refractoriness has been attempted with R-Verapamil, a well tolerated calcium channel blocker. This drug significantly decreased the incidence of lung foci after intravenous seeding of the R3230AC rat adenocarcinoma; this effect was correlated with reduction in the expression of P-glycoprotein. The simultaneous administration of antiestrogens with a non-toxic enantiomer of Verapamil was beneficial in the tumour model investigated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Adenocarcinoma / drug therapy*
  • Adenocarcinoma / pathology
  • Animals
  • Drug Resistance
  • Female
  • Isomerism
  • Liver / drug effects
  • Liver / enzymology
  • Liver / pathology
  • Liver Function Tests
  • Lung Neoplasms / prevention & control
  • Lung Neoplasms / secondary*
  • Mammary Neoplasms, Experimental / drug therapy*
  • Mammary Neoplasms, Experimental / pathology
  • Membrane Glycoproteins / analysis*
  • Rats
  • Rats, Inbred F344
  • Tamoxifen / therapeutic use*
  • Verapamil / therapeutic use*
  • Verapamil / toxicity

Substances

  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Membrane Glycoproteins
  • Tamoxifen
  • Verapamil