am-356 and Lung-Neoplasms

Cannabinoids, in addition to having palliative benefits in cancer therapy, have been associated with anticarcinogenic effects. Although the antiproliferative activities of cannabinoids have been intensively investigated, little is known about their effects on tumor invasion.. Matrigel-coated and uncoated Boyden chambers were used to quantify invasiveness and migration, respectively, of human cervical cancer (HeLa) cells that had been treated with cannabinoids (the stable anandamide analog R(+)-methanandamide [MA] and the phytocannabinoid delta9-tetrahydrocannabinol [THC]) in the presence or absence of antagonists of the CB1 or CB2 cannabinoid receptors or of transient receptor potential vanilloid 1 (TRPV1) or inhibitors of p38 or p42/44 mitogen-activated protein kinase (MAPK) pathways. Reverse transcriptase-polymerase chain reaction (RT-PCR) and immunoblotting were used to assess the influence of cannabinoids on the expression of matrix metalloproteinases (MMPs) and endogenous tissue inhibitors of MMPs (TIMPs). The role of TIMP-1 in the anti-invasive action of cannabinoids was analyzed by transfecting HeLa, human cervical carcinoma (C33A), or human lung carcinoma cells (A549) cells with siRNA targeting TIMP-1. All statistical tests were two-sided.. Without modifying migration, MA and THC caused a time- and concentration-dependent suppression of HeLa cell invasion through Matrigel that was accompanied by increased expression of TIMP-1. At the lowest concentrations tested, MA (0.1 microM) and THC (0.01 microM) led to a decrease in invasion (normalized to that observed with vehicle-treated cells) of 61.5% (95% CI = 38.7% to 84.3%, P < .001) and 68.1% (95% CI = 31.5% to 104.8%, P = .0039), respectively. The stimulation of TIMP-1 expression and suppression of cell invasion were reversed by pretreatment of cells with antagonists to CB1 or CB2 receptors, with inhibitors of MAPKs, or, in the case of MA, with an antagonist to TRPV1. Knockdown of cannabinoid-induced TIMP-1 expression by siRNA led to a reversal of the cannabinoid-elicited decrease in tumor cell invasiveness in HeLa, A549, and C33A cells.. Increased expression of TIMP-1 mediates an anti-invasive effect of cannabinoids. Cannabinoids may therefore offer a therapeutic option in the treatment of highly invasive cancers.

Topics: Arachidonic Acids; Biocompatible Materials; Cannabinoid Receptor Antagonists; Cannabinoids; Cell Movement; Collagen; Cytological Techniques; Down-Regulation; Dronabinol; Drug Combinations; Female; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; HeLa Cells; Humans; Immunoblotting; Laminin; Lung Neoplasms; Matrix Metalloproteinase 1; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Neoplasm Invasiveness; p38 Mitogen-Activated Protein Kinases; Protein Kinase Inhibitors; Proteoglycans; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Reverse Transcriptase Polymerase Chain Reaction; RNA, Small Interfering; Signal Transduction; Tissue Inhibitor of Metalloproteinase-1; Transfection; TRPV Cation Channels; Uterine Cervical Neoplasms

Increased COX-2 expression and elevated PGE2 have been associated with a poor prognosis in lung cancer. Cannabinoids have been known to exert some of their biological effects via modulation of prostaglandin production. We evaluated the impact of methanandamide on COX-2 expression, PGE2 production, and tumor growth in murine lung cancer. Methanandamide administration (5 mg/kg, four times/wk i.p.) resulted in an increased rate of tumor growth (P<0.01 compared with diluent treated controls). The CB1 and CB2 receptor antagonists, SR141716 and SR144528, did not block the methanandamide-mediated increase in tumor growth. In vivo, methanandamide treatment increased the production of PGE2 at the tumor site as well as in splenocytes. Consistent with these results, methanandamide increased PGE2 and COX-2 levels in murine lung cancer cells in vitro via a cannabinoid receptor-independent mechanism. The COX-2-specific inhibitor, SC58236, abrogated methanandamide induction of PGE2 production in vitro and blocked methanandamide-enhanced tumor growth in vivo. Furthermore, the p38/MAPK inhibitor, SB203528, and the p42/44 inhibitor, PD98059, blocked methanandamide-mediated induction of PGE2 and COX-2. These results suggest that methanandamide augments tumor growth by a cannabinoid receptor-independent pathway that is associated with the up-regulation of COX-2.

Topics: Animals; Arachidonic Acids; Cell Division; Cyclooxygenase 2; Dinoprostone; Isoenzymes; Lung Neoplasms; Mice; Models, Biological; Prostaglandin-Endoperoxide Synthases; Pyrazoles; Receptors, Cannabinoid; Spleen; Sulfonamides