Abstract Nonmelanoma skin cancer is one of the most common malignancies in humans. Different therapeutic strategies for the treatment of these tumors are currently being investigated. Given the growth-inhibiting effects of cannabinoids on gliomas and the wide tissue distribution of the two subtypes of cannabinoid receptors (CB(1) and CB(2)), we studied the potential utility of these compounds in anti-skin tumor therapy. Here we show that the CB(1) and the CB(2) receptor are expressed in normal skin and skin tumors of mice and humans. In cell culture experiments pharmacological activation of cannabinoid receptors induced the apoptotic death of tumorigenic epidermal cells, whereas the viability of...

The G protein-coupled receptors CB2 (CB2R) and GPR55 are overexpressed in cancer cells and human tumors. Because a modulation of GPR55 activity by cannabinoids has been suggested, we analyzed whether this receptor participates in cannabinoid effects on cancer cells. Here we show that CB2R and GPR55 form heteromers in cancer cells, that these structures possess unique signaling properties, and that modulation of these heteromers can modify the antitumoral activity of cannabinoids in vivo. These findings unveil the existence of previously unknown signaling platforms that help explain the complex behavior of cannabinoids and may constitute new targets for therapeutic intervention in oncology.

Endocannabinoids are now emerging as suppressors of key cell-signaling pathways involved in cancer cell growth, invasion, and metastasis. We have previously observed that the metabolically stable anandamide analog, 2-methyl-2'-F-anandamide (Met-F-AEA) can inhibit the growth of thyroid cancer in vivo. Our hypothesis was that the anti-tumor effect observed could be at least in part ascribed to inhibition of neo-angiogenesis. Therefore, the aim of this study was to assess the anti-angiogenic activity of Met-F-AEA, to investigate the molecular mechanisms underlying this effect and whether Met-F-AEA could antagonize tumor-induced endothelial cell sprouting. We show that Met-F-AEA inhibited bFGF-stimulated endothelial cell proliferation, in a dose-dependent manner, and also...

Fluorouracil is the main chemotherapeutic drug used for gastrointestinal cancers, which suffers the important problem of treatment resistance. There is little information whether cannabinoid agonists can be used as an alternative drug for fluorouracil-resistant gastric cancer cells. In this study, we investigated the effects of a cannabinoid agonist, WIN-55,212-2, on 5-fluorouracil (5-FU)-resistant human gastric cancer cells, to examine whether the cannabinoid agonist may be an alternative therapy. Survival of the 5-FUresistant gastric cancer cell line, SNU-620-5FU/1000, was not significantly reduced even by a high dose of 5-FU treatment. However, WIN-55,212-2 inhibited the proliferation of SNU-620-5FU/1000 and enhanced their apoptosis, as indicated by an increase...

Background: ErbB2-positive breast cancer is characterized by highly aggressive phenotypes and reduced responsiveness to standard therapies. Although specific ErbB2-targeted therapies have been designed, only a small percentage of patients respond to these treatments and most of them eventually relapse. The existence of this population of particularly aggressive and non-responding or relapsing patients urges the search for novel therapies. The purpose of this study was to determine whether cannabinoids might constitute a new therapeutic tool for the treatment of ErbB2-positive breast tumors. We analyzed their antitumor potential in a well established and clinically relevant model of ErbB2-driven metastatic breast cancer: the MMTV-neu mouse. We also...

The long history of the medicinal use of Cannabis sativa and, more recently, of its chemical constituents, the cannabinoids, suggests that also the endogenous ligands of cannabinoid receptors, the endocannabinoids, and, particularly, their derivatives may be used as therapeutic agents. Studies aimed at correlating the tissue and body fluid levels of endogenous cannabinoid-like molecules with pathological conditions have been started and may lead to identify those diseases that can be alleviated by drugs that either mimic or antagonize the action of these substances, or modulate their biosynthesis and degradation. Hints for the therapeutic applications of endocannabinoids, however, can be obtained also from our previous...

Cannabinoids, the active components of marijuana and their derivatives, inhibit tumor growth in animal models, but the mechanism of their anti-tumoral action in vivo is still unclear. Because the generation of a new vascular supply (angiogenesis) is causally involved in the progression of the majority of solid tumors, the aim of this study was to test whether cannabinoids inhibit tumor angiogenesis.

As a therapeutic agent, most people are familiar with the palliative effects of the primary psychoactive constituent of Cannabis sativa (CS), Δ9 -tetrahydrocannabinol (THC), a molecule active at both the cannabinoid 1 (CB1) and cannabinoid 2 (CB2) receptor subtypes. Through the activation primarily of CB1 receptors in the central nervous system, THC can reduce nausea, emesis and pain in cancer patients undergoing chemotherapy. During the last decade, however, several studies have now shown that CB1 and CB2 receptor agonists can act as direct antitumor agents in a variety of aggressive cancers. In addition to THC, there are many other cannabinoids found in CS, and...

In addition to the well-known palliative effects of cannabinoids on some cancer-associated symptoms, a large body of evidence shows that these molecules can decrease tumour growth in animal models of cancer. They do so by modulating key cell signalling pathways involved in the control of cancer cell proliferation and survival. In addition, cannabinoids inhibit angiogenesis and decrease metastasis in various tumour types in laboratory animals. In this review, we discuss the current understanding of cannabinoids as antitumour agents, focusing on recent discoveries about their molecular mechanisms of action, including resistance mechanisms and opportunities for their use in combination therapy. Those observations have already contributed...

Objectives: The endocannabinoid system is an endogenous lipid signalling network comprising arachidonic-acid-derived ligands, cannabinoid (CB) receptors, transporters and endocannabinoid degrading enzymes. The CB1 receptor is predominantly expressed in neurons but is also co-expressed with the CB2 receptor in peripheral tissues. In recent years, CB receptor ligands, including D 9 -tetrahydrocannabinol, have been proposed as potential anticancer agents. Key findings: This review critically discusses the pharmacology of CB receptor activation as a novel therapeutic anticancer strategy in terms of ligand selectivity, tissue specificity and potency. Intriguingly, antitumour effects mediated by cannabinoids are not confined to inhibition of cancer cell proliferation; cannabinoids also reduce angiogenesis, cell...