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Overexpression of far upstream element binding proteins: A mechanism regulating proliferation and migration in liver cancer cells
Author(s) -
Malz Mona,
Weber Achim,
Singer Stephan,
Riehmer Vera,
Bissinger Michaela,
Riener MarcOliver,
Longerich Thomas,
Soll Christopher,
Vogel Arndt,
Angel Peter,
Schirmacher Peter,
Breuhahn Kai
Publication year - 2009
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.23051
Subject(s) - stathmin , hccs , cell growth , biology , cancer research , microbiology and biotechnology , cell migration , microtubule , motility , cell , hepatocellular carcinoma , genetics
Abstract Microtubule‐dependent effects are partly regulated by factors that coordinate polymer dynamics such as the microtubule‐destabilizing protein stathmin (oncoprotein 18). In cancer cells, increased microtubule turnover affects cell morphology and cellular processes that rely on microtubule dynamics such as mitosis and migration. However, the molecular mechanisms deregulating modifiers of microtubule activity in human hepatocarcinogenesis are poorly understood. Based on profiling data of human hepatocellular carcinoma (HCC), we identified far upstream element binding proteins (FBPs) as significantly coregulated with stathmin. Coordinated overexpression of two FBP family members (FBP‐1 and FBP‐2) in >70% of all analyzed human HCCs significantly correlated with poor patient survival. In vitro , FBP‐1 predominantly induced tumor cell proliferation, while FBP‐2 primarily supported migration in different HCC cell lines. Surprisingly, reduction of FBP‐2 levels was associated with elevated FBP‐1 expression, suggesting a regulatory interplay of FBP family members that functionally discriminate between cell division and mobility. Expression of FBP‐1 correlated with stathmin expression in HCC tissues and inhibition of FBP‐1 but not of FBP‐2 drastically reduced stathmin at the transcript and protein levels. In contrast, further overexpression of FBP‐1 did not affect stathmin bioavailability. Accordingly, analyzing nuclear and cytoplasmic areas of HCC cells revealed that reduced FBP‐1 levels affected cell morphology and were associated with a less malignant phenotype. Conclusion: The coordinated activation of FBP‐1 and FBP‐2 represents a novel and frequent pro‐tumorigenic mechanism promoting proliferation (tumor growth) and motility (dissemination) of human liver cancer cells. FBPs promote tumor‐relevant functions by at least partly employing the microtubule‐destabilizing factor stathmin and represent a new potential target structure for HCC treatment. (H EPATOLOGY 2009.)