jwh-133 and Breast-Neoplasms

Cannabinoids, the active components of the hemp plant Cannabis sativa, along with their endogenous counterparts and synthetic derivatives, have elicited anti-cancer effects in many different in vitro and in vivo models of cancer. While the various cannabinoids have been examined in a variety of cancer models, recent studies have focused on the role of cannabinoid receptor agonists (both CB(1) and CB(2)) in the treatment of estrogen receptor-negative breast cancer. This review will summarize the anti-cancer properties of the cannabinoids, discuss their potential mechanisms of action, as well as explore controversies surrounding the results.

Topics: Animals; Antineoplastic Agents, Phytogenic; Benzoxazines; Breast Neoplasms; Cannabinoids; Cell Proliferation; Cell Survival; Female; Humans; Male; Morpholines; Naphthalenes; Neoplasms; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Receptors, Estrogen; Signal Transduction

The cannabinoid type 2 receptor (CB2) has previously been implicated as a regulator of tumor growth, bone remodeling, and bone pain. However, very little is known about the role of the skeletal CB2 receptor in the regulation of osteoblasts and osteoclasts changes associated with breast cancer. Here we found that the CB2-selective agonists HU308 and JWH133 reduced the viability of a variety of parental and bone-tropic human and mouse breast cancer cells at high micromolar concentrations. Under conditions in which these ligands are used at the nanomolar range, HU308 and JWH133 enhanced human and mouse breast cancer cell-induced osteoclastogenesis and exacerbated osteolysis, and these effects were attenuated in cultures obtained from CB2-deficient mice or in the presence of a CB2 receptor blocker. HU308 and JWH133 had no effects on osteoblast growth or differentiation in the presence of conditioned medium from breast cancer cells, but under these circumstances both agents enhanced parathyroid hormone-induced osteoblast differentiation and the ability to support osteoclast formation. Mechanistic studies in osteoclast precursors and osteoblasts showed that JWH133 and HU308 induced PI3K/AKT activity in a CB2-dependent manner, and these effects were enhanced in the presence of osteolytic and osteoblastic factors such as RANKL (receptor activator of NFκB ligand) and parathyroid hormone. When combined with published work, these findings suggest that breast cancer and bone cells exhibit differential responses to treatment with CB2 ligands depending upon cell type and concentration used. We, therefore, conclude that both CB2-selective activation and antagonism have potential efficacy in cancer-associated bone disease, but further studies are warranted and ongoing.

Topics: Animals; Blotting, Western; Bone Marrow Cells; Breast Neoplasms; Cannabinoids; Cell Line, Tumor; Cell Proliferation; Cells, Cultured; Coculture Techniques; Culture Media, Conditioned; Humans; MCF-7 Cells; Mice, Knockout; Osteoblasts; Osteoclasts; Osteogenesis; Osteolysis; Parathyroid Hormone; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; RANK Ligand; Receptor, Cannabinoid, CB2; Signal Transduction

Cannabinoids have been reported to possess antitumorogenic activity. Not much is known, however, about the effects and mechanism of action of synthetic nonpsychotic cannabinoids on breast cancer growth and metastasis. We have shown that the cannabinoid receptors CB1 and CB2 are overexpressed in primary human breast tumors compared with normal breast tissue. We have also observed that the breast cancer cell lines MDA-MB231, MDA-MB231-luc, and MDA-MB468 express CB1 and CB2 receptors. Furthermore, we have shown that the CB2 synthetic agonist JWH-133 and the CB1 and CB2 agonist WIN-55,212-2 inhibit cell proliferation and migration under in vitro conditions. These results were confirmed in vivo in various mouse model systems. Mice treated with JWH-133 or WIN-55,212-2 showed a 40% to 50% reduction in tumor growth and a 65% to 80% reduction in lung metastasis. These effects were reversed by CB1 and CB2 antagonists AM 251 and SR144528, respectively, suggesting involvement of CB1 and CB2 receptors. In addition, the CB2 agonist JWH-133 was shown to delay and reduce mammary gland tumors in the polyoma middle T oncoprotein (PyMT) transgenic mouse model system. Upon further elucidation, we observed that JWH-133 and WIN-55,212-2 mediate the breast tumor-suppressive effects via a coordinated regulation of cyclooxygenase-2/prostaglandin E2 signaling pathways and induction of apoptosis. These results indicate that CB1 and CB2 receptors could be used to develop novel therapeutic strategies against breast cancer growth and metastasis.

Topics: Animals; Apoptosis; Benzoxazines; Breast Neoplasms; Cannabinoids; Cell Cycle; Cell Growth Processes; Cell Line, Tumor; Cell Movement; Cyclooxygenase 2; Dinoprostone; Female; Humans; Immunohistochemistry; Lung Neoplasms; Male; Mammary Neoplasms, Experimental; Mice; Mice, Inbred C3H; Mice, SCID; Mice, Transgenic; Microscopy, Confocal; Morpholines; Naphthalenes; Neoplasm Metastasis; Neovascularization, Pathologic; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; RNA, Small Interfering; Signal Transduction; Transfection; Xenograft Model Antitumor Assays