Inhibition of cancer cell invasion by cannabinoids via increased expression of tissue inhibitor of matrix metalloproteinases-1

Use of cannabinoid receptor agonists in cancer therapy as palliative and curative agents

Cannabinoids (the active components of Cannabis sativa) and their derivatives have received renewed interest in recent years due to their diverse pharmacological activities. In particular, cannabinoids offer potential applications as anti-tumour drugs, based on the ability of some members of this class of compounds to limit cell proliferation and to induce tumour-selective cell death. Although synthetic cannabinoids may have pro-tumour effects in vivo due to their immunosuppressive properties, predominantly inhibitory effects on tumour growth and migration, angiogenesis, metastasis, and also inflammation have been described. Emerging evidence suggests that agonists of cannabinoid receptors expressed by tumour cells may offer a novel strategy to treat cancer. In this chapter we review the more recent results generating interest in the field of cannabinoids and cancer, and provide novel suggestions for the development, exploration and use of cannabinoid agonists for cancer therapy, not only as palliative but also as curative drugs.

Changes in the endocannabinoid system may give insight into new and effective treatments for cancer

The endocannabinoid system comprises specific cannabinoid receptors such as Cb1 and Cb2, the endogenous ligands (anandamide and 2-arachidonyl glycerol among others) and the proteins responsible for their synthesis and degradation. This system has become the focus of research in recent years because of its potential therapeutic value several disease states. The following review describes our current knowledge of the changes that occur in the endocannabinoid system during carcinogenesis and then focuses on the effects of anandamide on various aspects of the carcinogenic process such as growth, migration, and angiogenesis in tumors from various origins.

A critical review of the cannabinoid receptor as a drug target for obesity management

The discovery of cannabinoids, with the well-known stimulatory effect of Cannabis sativa on appetite, has offered a new drug target for obesity treatment. Cannabinoids act on two different receptors: CB1 receptors which are sited in the brain and many peripheral tissues, and CB2 receptors which are primarily found in immune system cells. Cannabinoid receptor antagonists act centrally by blocking CB1 receptors, thereby reducing food intake. Moreover, they probably also act peripherally by increasing thermogenesis and therefore energy expenditure, as has been suggested by animal experiments. Despite these promising mechanisms of action, recent clinical studies examining the effect of the two CB1 receptor antagonists rimonabant and taranabant showed that the attained weight loss did not exceed that attained with other currently approved anti-obesity medications. Moreover, potentially severe psychiatric adverse effects limit their clinical use. As several new CB1 receptor antagonists are presently undergoing development, it remains to be elucidated to what extent they differ in terms of efficacy and safety. This review primarily discusses how close cannabinoid receptor antagonists are to the ideal anti-obesity drug, with respect to their mechanisms of action, clinical effectiveness and safety.

Expression and function of fatty acid amide hydrolase in prostate cancer

The hydrolysis of endocannabinoids has profound effects on the function of the endocannabinoid signaling system in the regulation of prostate carcinoma cells. Prostate carcinoma cells exhibit a wide range of hydrolysis activity for 2-arachidonoylglycerol (2-AG), the major endocannabinoid. However, enzyme(s) responsible for 2-AG hydrolysis and their functions in prostate cancer have not been characterized. In this study, we demonstrated that fatty acid amide hydrolase (FAAH) was differentially expressed in normal and prostate carcinoma cells. In PC-3 cells, overexpression of FAAH resulted in increased FAAH protein, 2-AG hydrolysis, cell invasion and cell migration. Conversely, small-interfering RNA (siRNA) knockdown of FAAH in LNCaP cells decreased FAAH protein, 2-AG hydrolysis and cell invasion. Furthermore, CAY10401, a FAAH inhibitor, decreased cell invasion and it enhanced the reduction of invasion in FAAH siRNA-transfected LNCaP cells. Immunohistochemistry staining of commercial tissue microarrays (TMAs) demonstrated FAAH staining in 109 of 157 cores of prostate adenocarcinomas but weak staining in 1 of 8 cores of normal prostate tissues. These results suggest that FAAH regulates 2-AG hydrolysis and invasion of prostate carcinoma cells and is potentially involved in prostate tumorigenesis.

Expression of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 in pancreatic carcinoma and their clinical significances

AIM: To investigate the expression of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1), and their correlations with the metastasis and prognosis of pancreatic carcinoma.

METHODS: Immunohistochemical staining (SP method) was used to measure MMP-9 and TIMP-1 expression in 63 cases of pancreatic carcinoma, 11 cases of chronic pancreatitis (CP) and 6 cases of normal pancreas.

RESULTS: The expression of MMP-9 in pancreatic carcinoma was significantly higher than that in chronic pancreatitis and normal pancreas (58.7% vs 18.1%, 0.0%; both P < 0.05), while the expression of TIMP-1 pancreatic carcinoma was significantly lower than that in normal pancreas (46.0% vs 100.0%, P < 0.05). MMP-9 and TIMP-1 expression in pancreatic carcinoma were correlated with lymph node involvements and distant metastases (P < 0.05); however, they had no correlations with the sex, age of patients and histological staging.

CONCLUSION: MMP-9 and TIMP-1 may be associated with the metastasis of pancreatic carcinoma.