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Pharm Res (2010) 27:21622174 DOI 10.1007/s11095-010-0219-2
RESEARCH PAPER
Decrease of Plasminogen Activator Inhibitor-1 May Contribute to the Anti-Invasive Action of Cannabidiol on Human Lung Cancer Cells
Robert Ramer & Anja Rohde & Jutta Merkord & Helga Rohde & Burkhard Hinz
Received: 15 February 2010 /Accepted: 8 July 2010 /Published online: 29 July 2010 # Springer Science+Business Media, LLC 2010
ABSTRACTPurpose Using human lung cancer cells, we evaluated the involvement of plasminogen activator inhibitor-1 (PAI-1) in the anti-invasive action of cannabidiol, a non-psychoactive cannabinoid.
Methods Invasion was quantified by a modified Boyden chamber assay. PAI-1 protein in cell culture media and PAI-1 mRNA were determined by immunoblotting and RT-PCR, respectively.
Results Cannabidiol caused a profound inhibition of A549 cell invasion, accompanied by a decreased expression and secretion of PAI-1. Cannabidiol's effects on PAI-1 secretion and invasion were suppressed by antagonists to CB1 and CB2 receptors as well as to transient receptor potential vanilloid 1. Recombinant human PAI-1 and PAI-1 siRNA led to a concentration-dependent up- and down-regulation of invasiveness, respectively, suggesting a crucial role of PAI-1 in A549 invasiveness. Evidence for a causal link between cannabidiol's effects on PAI-1 and invasion was provided by experiments showing a reversal of its anti-invasive action by addition of recombinant PAI-1 at non-proinvasive concentrations. Key data were confirmed in two other human lung cancer cell lines (H460, H358). In vivo, a significant downregulation of PAI-1 protein by cannabidiol was demonstrated in A549 xenografts. Conclusion Our data provide evidence for a hitherto unknown mechanism underlying the anti-invasive action of cannabidiol on human lung cancer cells.
KEY WORDS cannabidiol . lung cancer cells . matrigel invasion . plasminogen activator inhibitor-1
ABBREVIATIONSAM-251 N-(Piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide AM-630 (6-Iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indol-3-yl) (4-methoxyphenyl)methanoneCB1 cannabinoid receptor 1
CB2 cannabinoid receptor 2RT-PCR reverse transcriptase-polymerase chain reaction siRNA small-interfering RNATRPV1 transient receptor potential vanilloid 1WST-1 4-[3-(4-Iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1.6-benzene disulfonate
INTRODUCTION
Although the anti-tumorigenic effects of cannabinoids were described in 1975 (1), comprehensive studies on cannabinoids' possible use as anticancer drugs during the last decade provided stronger evidence for anti-proliferative (2,3), proapoptotic (4,5), anti-metastatic (6), and anti-angiogenic effects (7,8). Furthermore, recent data support the view that the endocannabinoid system contributes to endogenous antitumorigenic defence mechanisms (9) and that cannabinoid receptor antagonists may promote carcinogenesis in people who are at high risk of developing human colorectal cancers...