We have suggested that hedgehog signaling exerts major survival signals in CCA by interaction with the cell cycle regulating serine/threonine Selleckchem ICG-001 kinase polo-like kinase (PLK) 2 (Fingas et al., Hepatology 2013;58:1362-74). The objective of this study was to examine how specifically PLK1/2/3 proteins are expressed in human CCA as compared to normal liver tissue. We also aimed to identify possible associations between PLK1/2/3
protein expression and clinicopath-ological factors. Methods: We employed intrahepatic CCA samples from 73 (prior to resection untreated) patients with surrounding normal liver tissue as well as human HUCCT-1, Mz CHA1 and KMCH-1 CCA cells for these studies. Immunohisto-chemistry for PLK1/2/3 was performed using tissue microar-rays generated from the most representative vital tumor areas. Results: PLK1/2/3-immunoreactive cancer cells were present in most of the human CCA samples. However, on the protein level only PLK1 and especially PLK3 but not PLK2 was expressed in significantly higher amounts within CCA cells as compared to normal liver tissue. Because fibroblast growth factor (FGF) can induce PLK3 expression and also is present
in CCA, we examined the C59 wnt mouse effect of FGF on PLK3 in three CCA cell lines by quantitative RT PCR. Indeed, rhFGF rapidly increased PLK3 mRNA expression in all CCA cell lines giving an explanation for the abundant PLK3 presence. Clinicopathologically, strong PLK3 expression was associated with decreased lymph/blood vessel infiltration (P = 0.021), whereas higher levels of PLK1 were correlated with larger CCA tumor sizes (P = 0.047) indicating that in contrast to PLK1, PLK3 might be a positive predictor of a favorable clinical course in patients with CCA. Consistent with this finding, strong PLK3 expression (P = 0.049) among other factors like low T status (pT1/2, P = 0.015) and reduced lymph/blood vessel infiltration (L/V0, P = 0.003) was associated with
prolonged overall survival in CCA patients. Finally, multivariate Cox regression analysis Dichloromethane dehalogenase only confirmed pT1/2 and L/V0 statuses as independent predictors of improved patient survival rates. Conclusions: The results suggest that especially PLK3 predominantly is expressed in CCA cells and that high PLK3 protein levels are associated with prolonged overall survival. These observations may have implications for prognosis prediction of human CCA. Disclosures: Gernot M. Kaiser – Grant/Research Support: Novartis, Pfizer, Astellas, Roche The following people have nothing to disclose: Benjamin Juntermanns, Svenja Sydor, Andreas Paul, Hideo A. Baba, Ali Canbay, Christian Dominik Fingas Background: Notch signal activation is related to various types of cancer growth and mediates cancer stem cells (CSCs). Anti-tumor therapies targeting CSCs are important for avoiding recurrence.