2-Phenylindole sulfamates: inhibitors of steroid sulfatase with antiproliferative activity in MCF-7 breast cancer cells

A number of 2-phenylindole sulfamates with lipophilic side chains in I - or 5-position of the indole were synthesized and evaluated as steroid sulfatase (estrone sulfatase) inhibitors. Most of the new sulfamates inhibited the enzymatic hydrolysis of estrone sulfate in MDA-MB 231 breast cancer cells with IC50 values between 2 nM and I muM. A favorable position for a long side chain is the nitrogen of a carbamoyl group at C-5 of the indole when the phenyl ring carries the sulfamate function. These derivatives inhibit gene activation in estrogen receptor (ER)-positive MCF-7 breast cancer cells in submicromolar concentrations and reduce cell proliferation with IC50 values of ca. I muM. All of the potent inhibitors were devoid of estrogenic activity and have the potential for in vivo application as steroid sulfatase inhibitors. (C) 2004 Elsevier Ltd. All rights reserved.