Synthesis of 1-substituted 3-(chloromethyl)-6-aminoindoline (6-amino-seco-CI) DNA minor groove alkylating agents and structure-activity relationships for their cytotoxicity.
A series of racemic 6-amino-seco-cyclopropylindole (seco-CI) compounds was prepared by coupling 1-(tert-butyloxycarbonyl)-3-(chloromethyl)-6-nitroindoline with appropriate acids, followed by nitro group reduction, and evaluated for cytotoxicity in AA8, UV4, EMT6, and SKOV3 cell lines. These compounds are of interest due to their close structural relationship to known AT-specific alkylating agents and cytotoxins and also for the possible construction of stable amine-based prodrugs designed for tumor-specific release. Variations included indole or furan side chains with different substituents, sulfonamide or carboxamide linkers, extension of the minor groove binding side chain to two subunits, and the use of a pyrroylacryloyl unit previously reported to give extremely potent analogues. The parent compound, with a trimethoxyindole side chain, was a moderately potent cytotoxin (IC50 = 0.34 microM in AA8 cells, 4 h exposure). A single 5-methoxy group on the indole minor groove binding unit was sufficient to maintain potency, and a series of dimethylaminoethoxy-substituted analogues retained the cytotoxicity of the parent compound, while providing increased aqueous solubility.
Auckland Cancer Society Research Centre, Department of Pathology, Faculty of Medicine and Health Science, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
J B
JB
Milbank
M
M
Tercel
G J
GJ
Atwell
W R
WR
Wilson
A
A
Hogg
W A
WA
Denny
D000818:Animals; D018906:Antineoplastic Agents, Alkylating / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D006224:Cricetinae; D004247:DNA / Q000378:metabolism*; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D051379:Mice; D051381:Rats; D012995:Solubility; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured
D018906:Antineoplastic Agents, Alkylating; D007211:Indoles; D004247:DNA