This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Song, I.-S. Articles by Kuo, M. T. Search for Related Content PubMed PubMed Citation Articles by Song, I.-S. Articles by Kuo, M. T.

Departments of ¹ Molecular Pathology and ² Experimental Therapeutics, University of Texas M.D. Anderson Cancer Center, Houston, Texas and ³ Department of Medical Oncology, Virginia Hospital, Miami, Florida

Requests for reprints: Macus Tien Kuo, Department of Molecular Pathology, University of Texas M.D. Anderson Cancer Center, Box 89, 1515 Holcombe Boulevard, Houston, TX 77030. Phone: 713-792-3256; Fax: 713-792-8424. E-mail: tkuo{at}mdanderson.org

Recent studies have shown that the mammalian high-affinity copper transporter encoded by Ctr1 is involved in the uptake of cisplatin. However, the roles of hCtr1 in cisplatin-sensitive and cisplatin-resistant mammalian cells have not been investigated. Here, we show that, of five cisplatin-resistant cell lines, only one (SR2) exhibited substantial reduction in hCtr1 expression as compared with that in its sensitive line small cell lung cancers (SCLC), whereas copper efflux transporters ATP7A and ATP7B were not significantly altered. SR2 exhibited cross-resistance to carboplatin but not to oxaliplatin. Transfection of expression hemagglutinin-tagged hCtr1 cDNA into SCLC and SR2 cells enhanced the uptake of copper, cisplatin, carboplatin, and oxaliplatin, suggesting that hCtr1 transporter can transport these platinum-based drugs. Whereas increased sensitivities to all these platinum drugs were observed in hCtr1-transfected SCLC cells, increased sensitivities to cisplatin and carboplatin but not to oxaliplatin were observed in hCtr1-transfected SR2 cells. These results suggest that SR2 acquired an additional unique intracellular resistance mechanism to oxaliplatin. Finally, using hCtr1 deletion mutants, we showed that the NH₂-terminal domain of hCtr1 was involved in transporting all these platinum-based antitumor agents. These results collectively show the importance of hCtr1 in the transport of platinum-based antitumor agents in cisplatin-sensitive and cisplatin-resistant variants.

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

⁴ I-S. Song et al., unpublished data.

Received 2/16/04; revised 9/10/04; accepted 10/14/04.