Staurosporine-induced apoptosis of HPV positive and negative human cervical cancer cells from different points in the cell cycle

Abstract

In the present study, we compare the sensitivity of CaSki and HeLa cells (HPV positive, wild-type p53) and C33A cells (HPV negative, mutated p53) to a protein kinase inhibitor, the staurosporine (ST). We show that ST can reversibly arrest the three cervical-derived cell lines, either in G1 or in G2/M. Beyond certain ST concentrations or/and over 24 h exposure, the cells underwent apoptosis. This process took place in G1 and G2/M for C33A and CaSki plus HeLa cell lines, respectively. By using an in vitro cell-free system, we demonstrated that cytoplasmic extracts from apoptotic cells were sufficient to induce hallmarks of programmed cell death on isolated nuclei. Moreover, we found that only G2/M cytoplasmic extracts from viable CaSki and HeLa cells supplemented with ST, triggered apoptosis while exclusively G1 cytoplasmic fractions from C33A cells were efficient. Our study describes a possible involvement of the HPV infection or/and p53 status in this different ST-induced apoptosis susceptibility. Cell Death and Differentiation (2001) 8, 234 ± 244.

Differential regulation of survivin by p53 contributes to cell cycle dependent apoptosis

“…Bernard et al showed that the p53 activity might involve in the apoptotic susceptibility of HPV infected cells when they compared the HPV-positive cells containing wild type p53 with the HPV-negative cells containing mutated p53 [15]. Our results here demonstrated that the cell-cycle dependent apoptosis was related with the differential transregulation of p53 on the basis of the silencing of E6 and restoration of functional p53.…”

“…It was reported that cells treated with some antitumor agents had different susceptibility to apoptosis in a cell cycle related manner [14]. This cell cycle stage-dependent susceptibility to apoptosis was also found in cells treated with staurosporine [15] and arsenite [16]. This different susceptibility may be explained by the variety of the lesion severity and the repair ability to the lesion.…”

Human papillomaviruses type 16+ and 18+ cervical carcinoma cells are sensitive to staurosporine‐mediated apoptosis

“…Indeed, our ST treatment on CaSki and HeLa cells induced the proteolytic cleavage of 116 kDa PARP protein to yield the characteristic 85 kDa fragment. Finally, typical morphological changes have been observed in our apoptotic HPV-positive cancer cells, and previously described in detail (Bernard et al, 2001). …”

“…Recently, we have demonstrated that staurosporine (ST), an inhibitor of multiple protein kinases, induces apoptosis of CaSki and HeLa cells, which specifically appears from the G2/M cycle phase (Bernard et al, 2001). However, the mechanisms by which ST activates the apoptotic cascade are not well understood.…”

“…HPV16 positive CaSki and HPV18 positive HeLa cell lines, derived from human cervical carcinomas, were cultured and synchronized in G2/M, as we previously described (Bernard et al, 2001). Then, apoptosis was induced with 300 nM of ST (for details, see Bernard et al, 2001).…”