title: Zidovudine induces the expression of cellular resistance affecting its antiviral activity.
abstract: We have previously shown that multidrug-resistant cells expressing the multidrug transporter P-glycoprotein are less sensitive to the antiviral activity of AZT. Subsequently, we addressed the question whether AZT itself is able to induce cellular resistance to the drug. Indeed, CEM cells propagated in the presence of increasing concentrations of AZT become resistant to the antigrowth and antiviral activity of AZT but do not express detectable level of P-glycoprotein. Sensitivity of these cells to other compounds, such as vinblastine, vincristine, ddI, and ddC remained unchanged, indicating that, in contrast to P-glycoprotein-positive cells, AZT-induced resistance is specific for AZT. Interestingly, in AZT-induced resistant cells the intracellular accumulation of AZT and exogenous deoxythymidine, as well as thymidine kinase activity, are significantly reduced when compared with the parental cell line. Our findings show that AZT itself may directly induce the expression of cellular mechanisms leading to the acquisition of specific cellular resistance that can affect its antiviral activity.
authors.affiliation: Institute of Virology, University La Sapienza, Rome, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Dianzani
authors.forename: G
authors.initials: G
authors.lastname: Antonelli
authors.forename: O
authors.initials: O
authors.lastname: Turriziani
authors.forename: E
authors.initials: E
authors.lastname: Riva
authors.forename: E
authors.initials: E
authors.lastname: Simeoni
authors.forename: C
authors.initials: C
authors.lastname: Signoretti
authors.forename: S
authors.initials: S
authors.lastname: Strosselli
authors.forename: M
authors.initials: M
authors.lastname: Cianfriglia
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004279:DNA, Viral / Q000096:biosynthesis; D004352:Drug Resistance, Microbial; D015497:HIV-1 / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D013936:Thymidine / Q000378:metabolism; D013937:Thymidine Kinase / Q000378:metabolism; D015215:Zidovudine / Q000493:pharmacokinetics / Q000494:pharmacology*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D004279:DNA, Viral; D015215:Zidovudine; D013937:Thymidine Kinase; D013936:Thymidine