The cannabinoid WIN 55,212-2 prevents neuroendocrine differentiation of LNCaP prostate cancer cells.
Neuroendocrine (NE) differentiation represents a common feature of prostate cancer and is associated with accelerated disease progression and poor clinical outcome. Nowadays, there is no treatment for this aggressive form of prostate cancer. The aim of this study was to determine the influence of the cannabinoid WIN 55,212-2 (WIN, a non-selective cannabinoid CB1 and CB2 receptor agonist) on the NE differentiation of prostate cancer cells.



NE differentiation of prostate cancer LNCaP cells was induced by serum deprivation or by incubation with interleukin-6, for 6 days. Levels of NE markers and signaling proteins were determined by western blotting. Levels of cannabinoid receptors were determined by quantitative PCR. The involvement of signaling cascades was investigated by pharmacological inhibition and small interfering RNA.



The differentiated LNCaP cells exhibited neurite outgrowth, and increased the expression of the typical NE markers neuron-specific enolase and βIII tubulin (βIII Tub). Treatment with 3 μM WIN inhibited NK differentiation of LNCaP cells. The cannabinoid WIN downregulated the PI3K/Akt/mTOR signaling pathway, resulting in NE differentiation inhibition. In addition, an activation of AMP-activated protein kinase (AMPK) was observed in WIN-treated cells, which correlated with a decrease in the NE markers expression. Our results also show that during NE differentiation the expression of cannabinoid receptors CB1 and CB2 dramatically decreases.



Taken together, we demonstrate that PI3K/Akt/AMPK might be an important axis modulating NE differentiation of prostate cancer that is blocked by the cannabinoid WIN, pointing to a therapeutic potential of cannabinoids against NE prostate cancer.
Department of System Biology, Biochemistry and Molecular Biology Unit, School of Medicine, Alcala University, Madrid, Spain.
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Morell
Department of System Biology, Biochemistry and Molecular Biology Unit, School of Medicine, Alcala University, Madrid, Spain.
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Bort
Division of Cell Signalling and Immunology, College of Life Sciences, University of Dundee, Dundee, Scotland, UK.
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Vara
Department of System Biology, Biochemistry and Molecular Biology Unit, School of Medicine, Alcala University, Madrid, Spain.
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Ramos-Torres
Department of System Biology, Biochemistry and Molecular Biology Unit, School of Medicine, Alcala University, Madrid, Spain.
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Rodríguez-Henche
Department of System Biology, Biochemistry and Molecular Biology Unit, School of Medicine, Alcala University, Madrid, Spain.
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Díaz-Laviada
D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000818:Animals; D048588:Benzoxazines / Q000494:pharmacology*; D015415:Biomarkers; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000187:drug effects*; D004195:Disease Models, Animal; D015870:Gene Expression; D006801:Humans; D008297:Male; D051379:Mice; D008954:Models, Biological; D009025:Morpholines / Q000494:pharmacology*; D009281:Naphthalenes / Q000494:pharmacology*; D018358:Neuroendocrine Tumors / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D043884:Receptor, Cannabinoid, CB1 / Q000235:genetics / Q000378:metabolism; D043885:Receptor, Cannabinoid, CB2 / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
D055372:AMP-Activated Protein Kinases; D048588:Benzoxazines; D015415:Biomarkers; D009025:Morpholines; D009281:Naphthalenes; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D043884:Receptor, Cannabinoid, CB1; D043885:Receptor, Cannabinoid, CB2; D058570:TOR Serine-Threonine Kinases; C070417:(3R)-((2,3-dihydro-5-methyl-3-((4-morpholinyl)methyl)pyrrolo-(1,2,3-de)-1,4-benzoxazin-6-yl)(1-naphthalenyl))methanone