HH regulates embryonal patterning through gradients of its 3 isoforms, however, in some adult tissues HH is also responsible for homeostasis and has effects on cell proliferation and apoptosis. Most importantly, deregulated HH can also lead to cancer development [1, 22, 33] and cyclopamine, an inhibitor of the HH pathway, is able to reduce metastasis Selleckchem ATM Kinase Inhibitor [8, 9]. At 32˚C ts p53 adopts wt conformation and cells accumulate in G1 phase of the cell cycle. The ratio of cells in S phase was strongly reduced in all tested cells. The immortalized cells from young embryos (402/534) were

nearly completely arrested in G1 phase after 24 h at 32˚C, whereas the immortalized cells from older embryos (602/534) showed a reduction in S phase, but not in G2 phase pointing to a different regulation in both cell types. However, transformed cells

from oRECs showed a stronger response to the temperature shift. After shifting the cells back to 37˚C, transformed cells from oRECs re-entered the cell cycle much faster then buy EPZ-6438 transformed cells from yRECs. As expected, transformed cells entered the cell cycle more quickly than their immortalized counterparts. The most salient finding of our present work is the strong impact of the endogenous cell traits in o vs y RECs. Our results show that even strong oncogenes such as mutated c-Ha-RAS and mutated TP53 are not able to override the intrinsic cellular program. Taken together, our results show that MEK inhibitor transformed RECs from older embryos show a higher growth potential than their counterparts from yRECs and are less susceptible

to the action of CDK inhibitors. However, after inactivation of c-Ha-Ras with an inhibitor of farnesylation, also the transformed oRECs are strongly susceptible to growth inhibition by CDK inhibitors. If the phenotype of a certain tumor is known, this knowledge might help to develop a customized treatment for tumors with constitutively activated Ras. Acknowledgements The paper was partially AR-13324 datasheet supported by a grant from the Austrian Funding Agency FWF (P19894-B11). Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. References 1. Berman DM, Karhadkar SS, Maitra A, Montes De Oca R, Gerstenblith MR, Briggs K, Parker AR, Shimada Y, Eshleman JR, Watkins DN, Beachy PA (2003) Widespread requirement for Hedgehog ligand stimulation in growth of digestive tract tumours. Nature. 425(6960):846–851PubMedCrossRef 2. Bernstein C, Bernstein H, Payne CM, Garewal H (2002) DNA repair/pro-apoptotic dual-role proteins in five major DNA repair pathways: fail-safe protection against carcinogenesis. Mutat. Res. 511(2):145–178PubMedCrossRef 3. Blagosklonny MV (2002) P53: an ubiquitous target of anticancer drugs. Int. J.