R-verapamil decreases anti-estrogen resistance in a breast cancer model.
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.
Sunnybrook Health Science Centre, University of Toronto, Ontario, Canada.
J A
JA
Kellen
A
A
Wong
E
E
Georges
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Ling
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000230:Adenocarcinoma / Q000188:drug therapy* / Q000473:pathology; D000818:Animals; D004351:Drug Resistance; D005260:Female; D007536:Isomerism; D008099:Liver / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D008111:Liver Function Tests; D008175:Lung Neoplasms / Q000517:prevention & control / Q000556:secondary*; D008325:Mammary Neoplasms, Experimental / Q000188:drug therapy* / Q000473:pathology; D008562:Membrane Glycoproteins / Q000032:analysis*; D051381:Rats; D011916:Rats, Inbred F344; D013629:Tamoxifen / Q000627:therapeutic use*; D014700:Verapamil / Q000627:therapeutic use* / Q000633:toxicity
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D008562:Membrane Glycoproteins; D013629:Tamoxifen; D014700:Verapamil