title: Syntheses and structure-activity relationships of the second-generation antitumor taxoids: exceptional activity against drug-resistant cancer cells.
abstract: A series of new 3'-(2-methyl-1-propenyl) and 3'-(2-methylpropyl) taxoids with modifications at C-10 was synthesized by means of the beta-lactam synthon method using 10-modified 7-(triethylsilyl)-10-deacetylbaccatin III derivatives. The new taxoids thus synthesized show excellent cytotoxicity against human ovarian (A121), non-small-cell lung (A549), colon (HT-29), and breast (MCF-7) cancer cell lines. All but one of these new taxoids possess better activity than paclitaxel and docetaxel in the same assay, i.e., the IC50 values of almost all the taxoids are in the subnanomolar level. It is found that a variety of modifications at C-10 is tolerated for the activity against normal cancer cell lines, but the activity against a drug-resistant human breast cancer cell line expressing MDR phenotype (MCF7-R) is highly dependent on the structure of the C-10 modifier. A number of the new taxoids exhibit remarkable activity (IC50 = 2.1-9.1 nM) against MCF7-R. Among these, three new taxoids, SB-T-1213 (4a), SB-T-1214 (4b), and SB-T-1102 (5a), are found to be exceptionally potent, possessing 2 orders of magnitude better activity than paclitaxel and docetaxel. The observed exceptional activity of these taxoids may well be ascribed to an effective inhibition of P-glycoprotein binding by the modified C-10 moieties. The new taxoid SB-T-1213 (4a) shows an excellent activity (T/C = 0% at 12.4 and 7.7 mg/kg/dose, log10 cell kill = 2.3 and 2.0, respectively) against B16 melanoma in B6D2F1 mice via intravenous administration.
authors.affiliation: Department of Chemistry, State University of New York at Stony Brook 11794-3400, USA.
authors.forename: I
authors.initials: I
authors.lastname: Ojima
authors.forename: J C
authors.initials: JC
authors.lastname: Slater
authors.forename: E
authors.initials: E
authors.lastname: Michaud
authors.forename: S D
authors.initials: SD
authors.lastname: Kuduk
authors.forename: P Y
authors.initials: PY
authors.lastname: Bounaud
authors.forename: P
authors.initials: P
authors.lastname: Vrignaud
authors.forename: M C
authors.initials: MC
authors.lastname: Bissery
authors.forename: J M
authors.initials: JM
authors.lastname: Veith
authors.forename: P
authors.initials: P
authors.lastname: Pera
authors.forename: R J
authors.initials: RJ
authors.lastname: Bernacki
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000138:chemical synthesis* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy; D000077143:Docetaxel; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D008546:Melanoma, Experimental / Q000188:drug therapy; D051379:Mice; D008819:Mice, Nude; D015394:Molecular Structure; D010051:Ovarian Neoplasms / Q000188:drug therapy; D017239:Paclitaxel / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000627:therapeutic use; D013329:Structure-Activity Relationship; D043823:Taxoids; D014407:Tumor Cells, Cultured
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000972:Antineoplastic Agents, Phytogenic; C101720:SB T-1102; C101718:SB T-1213; C101719:SB T-1214; D043823:Taxoids; D000077143:Docetaxel; D017239:Paclitaxel