The caspases are primarily involved in the cleavage of PARP-1 into two fragments and this has become EX 527 cell line a general hallmark of apoptosis [25–29]. Results of Figure 4 (large panel) show a relevant immuno-positivity to PARP-1 in cells treated with PD166866 (24 hours 50 μM) which is also monitored in positive control cells where apoptosis was caused

by the administration of H2O2 (upper left panel). The overall conclusion is that the cells treated with the drug are found actually in a condition of advanced apoptosis. Figure 4 Accumulation Poly-ADP-Ribose-Polymerase (PARP) in cells treated with PD166866 evidenced by imuno-histochemistry. Cells were treated with the drug (50 μM for 24 hours) and processed by immuno-histochemical techniques JNK-IN-8 mw to visualize the intracellular accumulation of PARP. The dark nuclei indicate accumulation of this enzyme in treated cells (large panel). The immuno-reaction also occurs in positive control cells treated with H202 (left small panel) while it is almost absent in untreated control cells. These results indicate cell death. Discussion The family of Growth Factor Receptors (FGFR) is constituted by tyrosine kinases involved in a number of different cell functions ranging

from cell growth control to mytogenesis and differentiation. Consequently, the interruption of the tyrosine-kinase signal transduction is considered a powerful strategy to inhibit angiogenesis and tumor cell proliferation: therefore fibroblast growth factors and their high-affinity receptors play a crucial role for cell growth survival and maintenance. The interplay between growth factors and their receptors is indeed a very complex one; however, the overall emerging picture is that PD166866, as a tyrosine kinase inhibitor, is able to invalidate the protective action exerted by different

agents inducing apoptosis [30, 31]. SPTLC1 In any case, inhibition of the FGF receptors mediated by small molecules such as SU5402 and PD166866 have been recently shown to reduce growth, survival and motility, as well as clonogenic potential in non small cancer lung cell lines (SSCLC) [32]. The data reported here indicate that one of the cellular targets of the drug may be the membrane of the HeLa cells which is agreement with the membrane localization of the FGFR. The treatment with PD166866 apparently causes a mitochondrial deficit and an oxidative stress, as demonstrated respectively, by the MTT assay and by the increase of the intracellular concentration of malonyl-dihaldeyde. However, rationalizing how the drug could selleck chemicals activate these processes is not an easy task. In any case, the impact of PD166866 on the overall cell metabolism [11] cannot be disregarded as an element of serious perturbation of the cell homeostasis. It may be argued that apoptosis could not be the only death process activated by PD166866.