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Marijuana Cuts Lung Cancer Tumor Growth In Half, Study Shows
The active ingredient in marijuana cuts tumor growth in common lung cancer in half and significantly reduces the ability of the cancer to spread, say researchers at Harvard University who tested the chemical in both lab and mouse studies.
 They say this is the first set of experiments to show that the compound, Delta-tetrahydrocannabinol (THC), inhibits EGF-induced growth and migration in epidermal growth factor receptor (EGFR) expressing non-small cell lung cancer cell lines. Lung cancers that over-express EGFR are usually highly aggressive and resistant to chemotherapy. THC that targets cannabinoid receptors CB1 and CB2 is similar in function to endocannabinoids, which are cannabinoids that are naturally produced in the body and activate these receptors. The researchers suggest that THC or other designer agents that activate these receptors might be used in a targeted fashion to treat lung cancer. "The beauty of this study is that we are showing that a substance of abuse, if used prudently, may offer a new road to therapy against lung cancer," said Anju Preet, Ph.D., a researcher in the Division of Experimental Medicine. Acting through cannabinoid receptors CB1 and CB2, endocannabinoids (as well as THC) are thought to play a role in variety of biological functions, including pain and anxiety control, and inflammation. Although a medical derivative of THC, known as Marinol, has been approved for use as an appetite stimulant for cancer patients, and a small number of U.S. states allow use of medical marijuana to treat the same side effect, few studies have shown that THC might have anti-tumor activity, Preet says. The only clinical trial testing THC as a treatment against cancer growth was a recently completed British pilot study in human glioblastoma. In the present study, the researchers first demonstrated that two different lung cancer cell lines as well as patient lung tumor samples express CB1 and CB2, and that non-toxic doses of THC inhibited growth and spread in the cell lines. "When the cells are pretreated with THC, they have less EGFR stimulated invasion as measured by various in-vitro assays," Preet said. Then, for three weeks, researchers injected standard doses of THC into mice that had been implanted with human lung cancer cells, and found that tumors were reduced in size and weight by about 50 percent in treated animals compared to a control group. There was also about a 60 percent reduction in cancer lesions on the lungs in these mice as well as a significant reduction in protein markers associated with cancer progression, Preet says. Although the researchers do not know why THC inhibits tumor growth, they say the substance could be activating molecules that arrest the cell cycle. They speculate that THC may also interfere with angiogenesis and vascularization, which promotes cancer growth. Preet says much work is needed to clarify the pathway by which THC functions, and cautions that some animal studies have shown that THC can stimulate some cancers. "THC offers some promise, but we have a long way to go before we know what its potential is," she said. Cannabis (Marijuana) May Help Alleviate Allergic Skin Disease Administering a substance found in the cannabis plant can help the body's natural protective system alleviate an allergic skin disease (allergic contact dermatitis), an international group of researchers from Germany, Israel, Italy, Switzerland and the U.S. has found. Allergic contact dermatitis is caused by reaction to something that directly contacts the skin. Many different substances (allergens) can cause allergic contact dermatitis. Usually these substances cause no trouble for most people, but if the skin is sensitive or allergic to the substance, any exposure will produce a rash, which may become very severe. Allergic contact dermatitis affects about 5 percent of men and 11percent of women in industrialized countries and is one of the leading causes for occupational diseases. An article describing the work of the international research group, led by Dr Andreas Zimmer from the University of Bonn, was published recently in the journal Science. The article deals with alleviating allergic skin disease through what is called the endocannabinoid system. Among the members of the group is Prof. Raphael Mechoulam of the Hebrew University of Jerusalem School of Pharmacy. In earlier work, Prof.Mechoulam's research group at the Hebrew University isolated two naturally occurring cannabinoid (cannabis-like) components -- one from the brain, named anandamide (from the word ananda, meaning supreme joy in Sanskrit), and another from the intestines named 2-AG. These two cannabinoids, plus their receptors and various enzymes that are involved in the cannnabinoids' syntheses and degradations, comprise the endocannabinoid system. These materials have similar effects to those of the active components in hashish and marijuana, produced from the cannabis plant. Research by groups throughout the world has since shown that the endocannabinoid system is involved in many physiological processes, including the protective reaction of the mammalian body to a long list of neurological diseases, such as multiple sclerosis, Alzheimer's and Parkinson's. In the article in Science, the researchers detail how the endocannabinoid system serves as a major regulator of cutaneous (skin) contact hypersensitivity (CHS) in a mouse model. In this model, they showed, for example, that mice lacking cannabinoid receptors display exacerbated inflammatory skin responses to an allergen. Because the data indicate that enhanced activation of the endocannabinoid system may function to dampen the CHS response, the researchers administered cannabinoids such as tetrahydrocannabinol (THC), a constituent derived from the cannabis plant, to the experimental animals. They findings showed that the THC significantly decreased the allergic reaction in comparison to untreated mice. In order to better understand the molecular mechanism that may contribute to the increased CHS in cannabinoid-receptor deficient mice, the researchers performed a series of experiments which showed that mouse skin cells produce a specific chemical (a chemokine) which is involved in the annoying disease reaction. Activation of the endocannabinoid system in the skin upon exposure to a contact allergen lowers the allergic responses through modulating the production of this chemokine. The results thus clearly show a protective role for the endocannabinoid system in contact allergy in the skin and suggest that development of cannabinoid compounds based on elements produced from the cannabis plant could enhance therapeutic treatment for humans. Note: This story has been adapted from a news release issued by The Hebrew University of Jerusalem. Comments:
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