Small P-gp modulating molecules: SAR studies on tetrahydroisoquinoline derivatives.

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Colabufo NA, Berardi F, Cantore M, Perrone MG, Contino M, Inglese C, Niso M, Perrone R, Azzariti A, Simone GM, Porcelli L, Paradiso A

Small P-gp modulating molecules: SAR studies on tetrahydroisoquinoline derivatives.

Bioorg Med Chem. 2008 Jan 1;16(1):362-73. Epub 2007 Sep 25.

PubMed ID

17936633 [ View in PubMed

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Abstract

The development of small molecules as P-gp modulating agents and SAR studies on these ligands represented the aim of the present work. A series of 6,7-dimethoxytetrahydroisoquinoline derivatives was prepared and their ability to inhibit P-gp activity has been evaluated. The basic nucleus of these compounds, common to the best P-gp inhibitors such as Tariquidar and Elacridar, has been functionalized with no-basic moiety from our studied sigma receptor ligands displaying potent P-gp inhibition. The best results were obtained for compounds 3c and 3a (EC(50)=1.64 and 4.86 microM, respectively) and these results were remarkable because Elacridar showed in the same biological evaluation similar inhibitory activity (EC(50)=2 microM). SAR studies displayed that the removal of double bond on the spacer or its shifting into tetraline ring decreased the P-gp inhibiting activity. Moreover, the P-gp inhibition mechanism of tested compounds was investigated by three selected biological experiments. The results displayed that only compound 3c was P-gp inhibitor as Elacridar, while compound 3a and reference compounds Cyclosporin A and Verapamil modulated P-gp activity saturating the efflux pump as substrates. Flow cytometry studies carried out in Doxorubicin resistant breast cancer cell line (MCF7/Adr) confirmed that compound 3c increased Doxorubicin cell accumulation 5.7-fold. In addition, in MCF7/Adr, antiproliferative effect of 5 microM Doxorubicin shifted from 5% to 95% when co-administered with compound 3c (20 microM). The present study suggested a new class of small molecules displaying P-gp inhibitor activity differing from reference compounds Elacridar and Tariquidar for a simplified, and in the meantime, efficacious no-basic moiety.

DrugBank Data that Cites this Article

Drugs

Elacridar

Binding Properties

Drug	Target	Property	Measurement	pH	Temperature (°C)
Cyclosporine	P-glycoprotein 1	EC 50 (nM)	80000	N/A	N/A	Details
Elacridar	P-glycoprotein 1	EC 50 (nM)	2000	N/A	N/A	Details
Verapamil	P-glycoprotein 1	EC 50 (nM)	20000	N/A	N/A	Details