Differential responses of human hepatocytes to the non-nucleoside HIV-1 reverse transcriptase inhibitor nevirapine

Abstract

-Nevirapine is a non-nucleoside reverse transcriptase (RT) inhibitor used for the treatment of AIDS and the prevention of mother-to-child transmission of HIV-1. Despite its therapeutic ben--ity. The present study examined the effects of nevirapine on cell growth and death in human hepatocyte HepG2 cells and THLE2 cells and the possible pathways involved in these effects. The concentrations of nevirapine inhibiting 50% cell growth were similar for both cell lines. Nevirapine (0-250 μM) treatment caused a slight increase in the amount of lactate dehydrogenase released into the medium. Apoptotic cell death did not contribute to the decrease in viable cells. Exposing of HepG2 cells to nevirapine caused cells, the percentage of cells in G1/G0 phase was increased and cellular senescence was induced in a concentration-dependent manner. Endogenous non-telomeric RT activity was not detected in either cell line. Western blot analysis indicated lower levels of p53 and phospho-p53 (ser15) in HepG2 cells as compared -ment. These data demonstrate that nevirapine inhibits cell growth, induces cell cycle arrest at different phases, and has different effects on cellular senescence in HepG2 cells and THLE2 cells. The differential responses appear to be related to differences in the basal levels of p53 in the HepG2 cells and THLE2 cells.

Nevirapine induced mitochondrial dysfunction in HepG2 cells

“…In a previous study we determined that the IC 50 of NVP in HepG2 cells was approximately 819 μM 13 , somewhat lower than the value determined by others 16 . Long term culture of cells with 819 μM NVP results in caspase 9 mediated cell death by week 3 of culture 13 .…”

Transcriptional profiling suggests that Nevirapine and Ritonavir cause drug induced liver injury through distinct mechanisms in primary human hepatocytes

“…The lower of the two concentrations chosen approximated the plasma threshold for clinical efficacy, and the higher dose was a low multiple of the C max . These were significantly below those which many culture systems typically use in their toxicity assessments(18). Fang and Beland(18) estimated an IC 50 of 813.7 μM for a 48 hour of Nevirapine which was almost six times the higher toxic concentration used in our study.…”

“…These were significantly below those which many culture systems typically use in their toxicity assessments(18). Fang and Beland(18) estimated an IC 50 of 813.7 μM for a 48 hour of Nevirapine which was almost six times the higher toxic concentration used in our study. Such high concentrations are useful for cytotoxicity metrics but may not reveal subtler pathway perturbations reflective of early mechanisms.…”

“…Non-flow systems, by virtue of their static nature, are also limited by the absence of circulation mediated effects such as oxygen and nutrient transport. Another factor undermining the physiological nature of drug response in these systems is that drug concentrations used are usually very different, often orders of magnitude higher, than the corresponding in vivo plasma or tissue concentrations achieving similar effects (18). The static nature of these systems also means that metabolites produced by the hepatocytes could build up over time in the interval between medium changes, and may not be reflective of physiological responses in vivo .…”

HIV-associated cellular senescence: A contributor to accelerated aging

“…HeLa cells treated with nevirapine underwent premature senescence that was associated with activation of the DNA damage response (Stefanidis et al, 2008). Nevirapine appears to have differential senescence induction capabilities because while it was able induce a growth arrest in both HepG2 cells and THLE2, an immortalized human liver cell line, senescence markers were only present in THLE2 cells (Fang and Beland, 2013). The relevance of these results towards HIV co-morbidities is uncertain because of the use of immortalized cell lines but to date no study has examined NNRTI senescence in primary cells.…”