Investigations into the physiologic processes affected by the psychoactive constitutuents of marihuana [delta-9-tetrahydrocannabinol (delta-9-THC) and delta-8-tetrahydrocannabinol (delta-8-THC)] purified from Cannabis sativa are extensive (1).
However, only recently have attempts been made to elucidate the biochemical basis for their cytotoxic or cytostatic activity. Leuchtenberger et al. (2) demonstrated that human lung cultures exposed to marihuana smoke showed alterations in DNA synthesis, with the appearance of anaphase bridges. (me: Anaphase bridges are one example of cancer cell abnormalities. Chromosomes are pulled in opposite directions by the spindle apparatus. This can result in double strand breaks that recombine as aberrations.)
A preliminary report from this laboratory (9) indicated that the ability of delta-9-THC to interfere with normal cell functions might prove efficacious against neoplasms. (me: an abnormal mass of tissue.) This report represents an effort to test various cannabinoids in several in vivo and in vitro tumor systems to determine the kinds of tumors that are sensitive to these compounds and reveal their possible biochemical sites of action(s).
...Delta-9-THC, delta-8-THC, and cannabinol (CBN) all inhibited primary Lewis lung tumor growth, whereas cannabidiol (CBD) enhanced tumor growth.
Oral administration of 25, 50, or 100 mg delta-9-THC/kg inhibited primary tumor growth by 48, 72, and 75% respectively, when measured 12 days post tumor inoculation (table 1)
This paper, published more than 25 years ago, indicates that cannabis is a first-line cancer treatment. The reason this information is not widely available is that there is little to no profit for anyone (other than those suffering from cancer and the ones who love them) in this knowledge. Cannabis is a naturally-occurring substance whose properties may not be copyrighted.
Researchers at Harvard published a study in 2007 that indicates cannabis cuts lung cancer tumors by 50%.
Science News
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.
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.
Research in Spain, published in 2009, demonstrated the mechanism by which cannabis induces cancer cell death.
Journal of Clinical Investigation
Δ9-Tetrahydrocannabinol (THC), the main active component of marijuana (7), exerts a wide variety of biological effects by mimicking endogenous substances — the endocannabinoids — that bind to and activate specific cannabinoid receptors (8). One of the most exciting areas of research in the cannabinoid field is the study of the potential application of cannabinoids as antitumoral agents (9). Cannabinoid administration has been found to curb the growth of several types of tumor xenografts in rats and mice (9, 10).
Based on this preclinical evidence, a pilot clinical trial has been recently run to investigate the antitumoral action of THC on recurrent gliomas (11). Recent findings have also shown that the pro-apoptotic and tumor growth–inhibiting activity of cannabinoids relies on the upregulation of the transcriptional co-activator p8 (12) and its target the pseudo-kinase tribbles homolog 3 (TRB3) (13).
However, the mechanisms that promote the activation of this signaling route as well as the targets downstream of TRB3 that mediate its tumor cell–killing action remain elusive. In this study we found that ER stress–evoked upregulation of the p8/TRB3 pathway induced autophagy via inhibition of the Akt/mTORC1 axis and that activation of autophagy promoted the apoptotic death of tumor cells. The uncovering of this pathway, which we believe is novel, for promoting tumor cell death may have therapeutic implications in the treatment of cancer.
California Breast Cancer Research Program (from Molecular Cancer Therapeutics)
An anti-cancer agent with a low toxicity profile that can both inhibit cancer cell growth and metastasis would be extremely valuable clinically. We have discovered that cannabidiol (CBD), a non-psychotropic cannabinoid constituent of the plant Cannabis sativa, can inhibit the growth, migration and invasion of aggressive breast cancer cells in culture.
Cannabinoid compounds, in general, have low toxicity profiles. Furthermore, our preliminary research demonstrated that CBD is a novel inhibitor of a protein whose activity has been closely linked to the aggressiveness of human breast cancers; called inhibitor of DNA binding-1 (Id-1). Whether CBD can inhibit the spread of metastatic breast cancer in vivo (in the body), compared to cell culture conditions, has not been determined.
However, CBD has been demonstrated to inhibit aggressive human brain cancers in vivo. Understanding the mechanisms behind the anti-cancer activity of CBD may lead to the validation of new biological targets for diagnostics and therapies for breast cancer.
Combining Cannabinoids Enhances Inhibition of Brain Cancer Cells
The study was done at the California Pacific Medical Center by researchers who combined a non-psychoactive ingredient of marijauna, cannabidiol (CBD), with Δ9-tetrahyrdocannabinol (Δ9-THC), the primary psychoactive ingredient in Cannabis. The findings demonstrated the inhibitory effect of these two ingredients on brain cancer cells when used together.
“Our study not only suggests that combining these two compounds creates a synergistic effect,” says Sean McAllister, Ph.D., a scientist at CPMCRI and the lead author of the study. “but it also helps identify molecular mechanisms at work here, and that may lead to more effective treatments for glioblastoma and potentially other aggressive cancers.”
It would seem that "magic nature," as noted in the Michael Pollan quote here, does indeed have knowledge to impart.
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