Nevirapine induces growth arrest and premature senescence in human cervical carcinoma cells

The aim of this study was to assess the impact of nevirapine on a cervix carcinoma cell line.

HeLa cells were cultured in Dulbecco's modified Eagle medium supplemented with 20% fetal bovine serum at 37 degrees C and humidified 10% CO(2) in air. Nevirapine was purified from commercially available Viramune (Boehringer-Ingelheim), diluted in dimethyl sulfoxide (DMSO, Sigma-Aldrich) in 350 microMu final concentration and added to cell cultures 5 h after seeding. The same DMSO volume (0.2% final concentration) was added to controls.

We found that nevirapine treatment induces reversible growth arrest and produces morphological changes in treated cells. In contrast with previous reports the observed effects of nevirapine did not correlate with promotion of differentiation, but with induction of premature senescence. Premature senescence as a response to anti-tumour treatment is a common effect of the most anti-cancer chemotherapeutics. Nevirapine treated cells strongly accumulated SA-b-Gal activity and also expressed increased levels of p53 and p21 when analyzed via RT-PCR. In order to further explore the potent mechanisms of premature senescence induction we performed pChk2-Thr68 immunofluorescence analysis and found that nevirapine treated cells exhibited increased number of nuclear foci, indicating activated DNA damage response.

We propose that at least in HeLa cell line nevirapine treatment exerts an effect far from the differentiation process, by introducing the cells into premature senescence. Based on these data, the effects of RT inhibitors should be further investigated since they may represent an additional agent against human cancer.