Expression and prognostic value of glutamate dehydrogenase in extrahepatic cholangiocarcinoma patients.

Glutamate dehydrogenase (GDH) produces a precursor to glutathione, an important molecule in maintaining cellular redox balance and the cancerous characteristics of tumor cells through intracellular signaling pathways. However, the underlying molecular mechanisms linking glutamate dehydrogenase and extrahepatic cholangiocarcinoma have not been elucidated yet. Herein, we examined GDH expression levels and evaluated its potential correlations with prognosis. Meanwhile, the therapeutic value of GDH targeting the Smad pathways in extrahepatic cholangiocarcinoma was explored. Immunohistochemical studies revealed that GDH expression level was correlated to CD34 expression, cellular differentiation, the presence or absence of capsular and vascular invasion, lymph node metastasis, neural invasion and patient age. Kaplan-Meier survival analysis and COX proportional hazards models demonstrated that the prognosis was closely associated with GDH expression, CD34 positivity, nerve infiltration and cell differentiation. GDH silencing significantly reduced the proliferation, migratory potential and invasive capability. We also demonstrated that GDH promoted cell proliferation and metastasis potentially through Smad-mediated induction of TGF-β signaling pathway. Therefore, GDH may be an important prognostic indicator and may provide a new target for novel treatments of extrahepatic cholangiocarcinoma.