the expected effect of butyrate on the b catenin was obviously seen also after short periods of incubation. z DEVD fmk applied an identical action, but with less efficiency. Treatment of HepG2 cells with 2 mM butyrate also reduced the levels of both types of pRb, but the effect was small com-pared to that within HuH 6 cells. Finally, in Chang liver cells, butyrate induced a moderate lower Icotinib only in phospho pRb. Phosphorylation of pRb occurs in the G1 phase of cell cycle by activation of cyclin dependent kinases, which are serine/threonine kinases dependent on the existence of G1 phase cyclins. The experience of cyclin CDK complexes is inhibited by factors belonging to the Cip/kip family, such as for instance p21 and p27. As shown in Fig. 6, therapy of HuH 6 cells with 2 mM butyrate significantly reduced the amount of equally cyclins D and E. This effect was suppressed by z VADfmk and paid off by z DEVD fmk. But, treatment of HuH 6 cells with butyrate did not modify the amounts of CDK4 and CDK2 or those of p27 and p21. In spite of the essential role exerted from the solution of the tumor suppressor gene p53 in many apoptotic pathways, butyrate induced apoptosis is shown to Skin infection be independent of p53 in many systems. Our results demonstrate that therapy with butyrate caused a small reduction in p53 in both HuH 6 and HepG2 cells. Thus, in hepatoma cells also the butyrate effect seemed to be independent of p53. The members of the Bcl 2 family of proteins are essential regulators of apoptosis. In order to individuate the role exerted by these factors in butyrate caused apoptosis, we first ascertained the current presence of anti apoptotic factors with this family in the cell lines used in our experiments. We noticed that the anti apoptotic aspect Bcl 2 was undetectable in HuH 6 cells, while a low content was present in HepG2 cells. On the other hand, non tumor Chang liver cells exhibited a high content of the factor. We also analysed Bcl XL, a Bcl 2 homologue with antiapoptotic action, two services and products Ibrutinib ic50 of the Bcl X gene, and Bcl Xs, an as an alternative spliced variant of the Bcl X gene with pro apoptotic activity. In while Bcl X-s was undetectable, extracts of the three cell lines a group of 3-1 kDa corresponding to Bcl XL was obviously identified. Treatment of HuH 6 cells with 2 mM butyrate for 24 h induced a decrease in BclXL and the appearance of a 2-1 kDa band corresponding to Bcl Xs. After 48 h, the results were more evident, with a remarkable increase in the intensity of the 21 kDa band, while the amount of Bcl XL reduced to 30 % of control. The effects on Bcl X isoforms were also dependent on the measure of butyrate employed. The decrease in Bcl XL induced by butyrate was suppressed by the addition of z VAD fmk, a broad spectrum caspase inhibitor, and significantly reduced by z DEVDfmk, a selective inhibitor of caspase 3.