10th International Workshop on Adverse Drug Reactions and Lipodystrophy in HIV 6-8 November 2008, London, UK

CLINICAL CONCENTRATIONS OF EFAVIRENZ (EFV) REDUCE CELLULAR PROLIFERATION AND VIABILITY IN SEVERAL HUMAN CELL LINES

Antiviral Therapy 2008; 13(Suppl. 4):A23 (abstract no. P-02)

N Apostolova¹, A Blas-García², D Ballesteros³, Y Gonzalez², A Morán², LJ Gómez-Sucerquia³ and JV Esplugues^1
1CIBERehd-University of Valencia, Valencia, Spain; ²University of Valencia, Valencia, Spain; ³Fundacion Juan Esplugues, Valencia, Spain

Efavirenz (EFV)-containing therapies have been related to several side effects including hepatotoxic events and chronic disorders in lipid metabolism, but the possible mechanisms underlying these effects have received very little study. We evaluated the cytotoxic effects of clinical (10–25 µM) and supraclinical (50 µM) concentrations of EFV in various human cellular models. MTT assays after 24 h of culture in the presence of the drug revealed reduced viability in the human hepatoma cell line Hep3B (significant for all three concentrations and calculated as 84.59 ±8.82% decrease for 50 µM EFV), human cervix carcinoma cell line HeLa (71.92 ±5.49% reduction for 50 µM EFV) and primary human umbilical vein endothelial cells (HUVEC; 96.76 ±0.27% reduction for 50 µM EFV). This result was corroborated with 3-day proliferation experiments in which Hep3B were exposed to different concentrations of EFV. A significant reduction (60.1 ±6.54% after 3 days) was detected with 25 µM EFV, whereas cytotoxicity (97.01 ±1.13% reduction) was observed with 50 µM; however, no changes were detected with 10 µM EFV. With the aim of analysing the mechanisms responsible for this diminished cellular viability, we performed bivariate annexin V/propidium iodide analysis of HeLa cells using static cytometry, and found that EFV-treated cells (4 and 8 h) presented features of late or advanced apoptosis. We also observed a dose-dependent translocation of two mitochondrial proapoptotic proteins, cytochrome c and AIF, in Hep3B cells after EFV treatment (4 h), which was accompanied by a significant reduction in the mitochondrial membrane potential (ΔΨ_m), as measured by TMRM fluorescence. Confocal fluorescence microscopy experiments revealed dose-dependent activation of caspase-3 and -9 and an absence of activation of caspase-8, pointing to EFV induction of the intrinsic (mitochondrial) apoptotic pathway. In conclusion, clinical concentrations of EFV can be cytotoxic and lead to activation of apoptotic programmes in common cellular models. This suggests that the therapeutic range of EFV is rather narrow and also that prolonged administration of this drug could result in highly active antiretroviral therapy-related mitochondrial dysfunction.

Download PDF of this abstract.

2008-11-06
P-02

Copyright © 2008 - International Medical Press Ltd. Reproduction of this abstract (other than one copy for personal reference) must be cleared through the Medical Editor, International Medical Press, 36 St Mary-at-Hill, London EC3R 8DU, United Kingdom.