Tenofovir Disoproxil (GS 4331) is a nucleotide reverse transcriptase inhibitor to treat HIV and chronic Hepatitis B.

Human renal proximal tubular epithelial cell line (HK-2)cells were grown for 48 h followed by 24 to 72 h exposure to 0-28.8 μM TFV or vehicle, phosphate buffered saline (PBS). MTT (MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) and Trypan blue indicated that TFV diminished cell viability at 24-72 h. TFV decreased ATP levels at 72 h when compared to vehicle, reflecting mitochondrial dysfunction. TFV increased the oxidative stress biomarkers of protein carbonylation and 4-hydroxynonenol (4-HNE) adduct formation. Tumor necrosis factor alpha (TNFα) was released into the media following exposure to 14.5 and 28.8 μM TFV. Caspase 3 and 9 cleavage was induced by TFV compared to vehicle at 72 h. HK-2 cells are a sensitive model for TFV cytotoxicity and suggest that mitochondrial stress and apoptosis occur in HK-2 cells treated with TFV[1].

Human immortalized epithelial HK-2 cells were grown in a keratinocyte-free media with 50 μg/mL bovine pituitary extract and 5 ng/mL recombinant epithelial growth factor from Invitrogen. Cells were grown in a warm humidified incubator with constant settings of 37 °C and 5% CO2. HK-2 cells were plated into six-well tissue culture plates (750,000 cells/mL) and allowed to grow for 48 h. Media was replaced and cells were treated with a final concentration of 0, 1.5, 3.0, 4.75, 14.5, or 28.8 μM TFV for 24, 48, or 72 h. The vehicle was an equal volume of phosphate buffered saline (PBS). Abacavir was prepared in sterile water and cells were treated for 24 h with 0, 1.5, 3 or 6 μM of abacavir to evaluate renal sensitivity to an agent recognized to be less nephrotoxic. Following the treatment period, cells were collected with Trypsin-EDTA (0.25%) for sample analysis[1].