title: Transport and cytotoxicity of paclitaxel, docetaxel, and novel taxanes in human breast cancer cells.
abstract: The resistance of tumors to classic taxanes (paclitaxel and docetaxel) presents problems in chemotherapy. Thus, new taxanes with higher antitumor activity in resistant tumors are synthesized. This study compared cytotoxicity and transport of paclitaxel and docetaxel with novel taxanes SB-T-1103, SB-T-1214, and SB-T-1216 in adriamycin-sensitive (MDA-MB-435) and -resistant (NCI/ADR-RES) human breast cancer cells. The cell lines examined differ in adriamycin transport, suggesting different expression of ABC membrane transporters. Reverse transcription-polymerase chain reaction revealed that NCI/ADR-RES cells expressed high levels of P-glycoprotein mRNA, which was absent in MDA-MB-435 cells, while the opposite was true for MRP2 mRNA. Both cell lines shared or differently expressed eight other ABC transporters and LRP. NCI/ADR-RES cells were 1,000-fold more resistant to paclitaxel and 600-fold more resistant to docetaxel in MTT assay than MDA-MB-435 cells, but almost equally sensitive to SB-T-1103, SB-T-1214, and SB-T-1216. This complied with the fact that NCI/ADR-RES cells absorbed almost 20-fold less [14C]paclitaxel, about 7-fold less docetaxel, and almost equal amounts of SB-T-1103, SB-T-1214, and SB-T-1216 as the MDA-MB-435 cells. Verapamil increased uptake of [14C]paclitaxel by NCI/ADR-RES cells 7-fold and decreased its efflux 2.5-fold; in contrast, it weakly influenced uptake and increased the efflux in MDA-MB-435 cells. SB-T-1103 and SB-T-1216 did not influence transport of paclitaxel, but SB-T-1214 decreased [14C]paclitaxel uptake in both cell lines indicating inhibition of uptake. This suggests that the novel taxanes are not inhibitors of P-glycoprotein. However, novel taxanes exert much higher activity on resistant tumor cells than classic taxanes and seem to be potential drugs for therapy in taxane-resistant tumors.
authors.affiliation: Cell Growth Control Laboratory, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, 142 00, Prague 4, Czech Republic.
authors.forename: Marie
authors.initials: M
authors.lastname: Ehrlichova
authors.forename: Radka
authors.initials: R
authors.lastname: Vaclavikova
authors.forename: Iwao
authors.initials: I
authors.lastname: Ojima
authors.forename: Antonella
authors.initials: A
authors.lastname: Pepe
authors.forename: Larisa V
authors.initials: LV
authors.lastname: Kuznetsova
authors.forename: Jin
authors.initials: J
authors.lastname: Chen
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Truksa
authors.forename: Jan
authors.initials: J
authors.lastname: Kovar
authors.forename: Ivan
authors.initials: I
authors.lastname: Gut
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D001943:Breast Neoplasms; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D000077143:Docetaxel; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D020128:Inhibitory Concentration 50; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism; D017239:Paclitaxel / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D043823:Taxoids / Q000494:pharmacology*; D013997:Time Factors; D014700:Verapamil / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000903:Antibiotics, Antineoplastic; D000972:Antineoplastic Agents, Phytogenic; D000077143:Docetaxel; D004317:Doxorubicin; D026901:Membrane Transport Proteins; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D017239:Paclitaxel; D012333:RNA, Messenger; D043823:Taxoids; D014700:Verapamil; C000715087:ABCC2 protein, human; C101719:SB T-1214