title: A thermally targeted elastin-like polypeptide-doxorubicin conjugate overcomes drug resistance.
abstract: The ability of cancer cells to become simultaneously resistant to different drugs, a trait known as multidrug resistance, remains a major obstacle for successful anticancer therapy. One major mechanism of resistance involves cellular drug efflux by expression of P-glycoprotein (P-gp), a membrane transporter with a wide variety of substrates. Anthracyclines are especially prone to induction of resistance by the P-gp mechanism. P-gp mediated resistance is often confronted by use of P-gp inhibitors, synthesis of novel analogs, or conjugating drugs to macromolecular carriers in order to circumvent the efflux mechanism. In this report, the effect of free and Elastin-like polypeptide (ELP) bound doxorubicin (Dox) on the viability of sensitive (MES-SA and MCF-7) and multidrug resistant (MES-SA/Dx5 and NCI/ADR-RES) human carcinoma cells was studied in vitro. The resistant MES-SA/Dx5 cells demonstrated about 70 times higher resistance to free Dox than the sensitive MES-SA cells, and the NCI/ADR-RES cells were about 30 fold more resistant than the MCF-7 cells. However, the ELP-bound Dox was equally cytotoxic in both sensitive and resistant cell lines. The ELP-bound Dox was shown to accumulate in MES-SA/Dx5 cells, as opposed to free Dox, which was rapidly pumped out by the P-gp transporter. Since ELP is a thermally responsive carrier, the effect of hyperthermia on the cytotoxicity of the ELP-Dox conjugate was investigated. Both cytotoxicity and apoptosis were enhanced by hyperthermia in the Dox resistant cells. The results suggest that ELP-Dox conjugates may provide a means to thermally target solid tumors and to overcome drug resistance in cancer cells.
authors.affiliation: Department of Biochemistry, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
authors.forename: Gene L
authors.initials: GL
authors.lastname: Bidwell
authors.forename: Aisha N
authors.initials: AN
authors.lastname: Davis
authors.forename: Izabela
authors.initials: I
authors.lastname: Fokt
authors.forename: Waldemar
authors.initials: W
authors.lastname: Priebe
authors.forename: Drazen
authors.initials: D
authors.lastname: Raucher
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D016503:Drug Delivery Systems; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D004549:Elastin / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D010455:Peptides / Q000737:chemistry*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000903:Antibiotics, Antineoplastic; D010455:Peptides; D004317:Doxorubicin; D004549:Elastin