The neurotrophic factor neurturin contributes toward an aggressive cancer cell phenotype, neuropathic pain and neuronal plasticity in pancreatic cancer.
Neurotrophic factors possess an emerging role in the pathophysiology of several gastrointestinal disorders, regulating innervation, pain sensation and disease-associated neuroplasticity. Here, we aimed at characterizing the role of the neurotrophic factor neurturin (NRTN) and its receptor glial-cell-line-derived neurotrophic factor receptor alpha-2 (GFRα-2) in pancreatic cancer (PCa) and pancreatic neuropathy. For this purpose, NRTN and GFRα-2 were studied in normal human pancreas and PCa tissues via immunohistochemistry, quantitative reverse transcription-polymerase chain reaction, immunoblotting and correlated to abdominal pain. The impact of NRTN/GFRα-2 on PCa cell (PCC) biology was investigated via exposure to hypoxia, 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide viability and matrigel invasion assays in native and specific small interfering RNA-silenced PCCs. To assess the influence of NRTN on pancreatic neuroplasticity and neural invasion (NI), its impact was explored via an in vitro 'neuroplasticity assay' and a 3D neural migration assay. NRTN and GFRα-2 demonstrated a site-specific upregulation in PCa, predominantly in nerves, PCCs and extracellular matrix. Patients with severe pain demonstrated higher intraneural GFRα-2 immunoreactivity than patients with no pain. PCa tissue and PCCs contained increased amounts of NRTN, which was suppressed under hypoxia. NRTN promoted PCC invasiveness, and silencing of NRTN limited both PCC proliferation and invasion. Depletion of NRTN from PCa tissue extracts and PCC supernatants decreased axonal sprouting in neuronal cultures but did not influence glial density. Silencing of NRTN in PCCs boosted NI. We conclude that increased NRTN/GFRα-2 in PCa seems to promote an aggressive PCC phenotype and neuroplasticity in PCa. Accelerated NI following NRTN suppression constitutes a novel explanation for the attraction of PCC to nerves in the hypoxic PCa tumor microenvironment.


CONCLUSIONS
PCa is characterized by intrapancreatic neuroplasticity and NI. Here, we show that PCC produce the neurotrophic factor NRTN, which reinforces their biological properties, triggers neuroplastic alterations, NI and influences pain sensation via the GFRα-2 receptor.
Department of Surgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, Munich D-81675, Germany and.
Kun
K
Wang
Ihsan Ekin
IE
Demir
Jan G
JG
D'Haese
Elke
E
Tieftrunk
Kristina
K
Kujundzic
Stephan
S
Schorn
Baocai
B
Xing
Timo
T
Kehl
Helmut
H
Friess
Güralp O
GO
Ceyhan
D015746:Abdominal Pain / Q000378:metabolism*; D000818:Animals; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005260:Female; D005727:Ganglia, Spinal / Q000187:drug effects / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology; D051101:Neurturin / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D010190:Pancreatic Neoplasms / Q000473:pathology* / Q000503:physiopathology*; D020033:Protein Isoforms / Q000378:metabolism; D051381:Rats
C494990:GFRA2 protein, human; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; C495053:NRTN protein, human; D051101:Neurturin; D020033:Protein Isoforms