Micro Blood Vessel
The three stages of cancer, so called because there is no pain or indication of its presence growing in the body’s organs. It is at the initiation and promotion stages-before cancer has spread, or metastasized-that cancer is most curable.
The first and most significant line of defense against any cancer is to prevent it. With 1 in 4 people in the United States developing cancer, obviously we are not doing a great job at that. From hundreds of studies, we now know that various natural substances can neutralize free radicals, reduce the inflammatory response, and block angiogenesis, thus interfering with the three stages of cancer development. It’s past time to turn that knowledge into action.
The use of compounds from plants in the treatment and prevention of many diseases predates recorded history. Modern medicine has continued to use plants themselves, such as foxglove, from which the heart drug digitalis is extracted, as well as to use biologically active plant molecules as a template for synthetic drugs. Between 2000 and 2005, more than twenty new anticancer drugs originating from plants or bacteria came on the market. One older example, Taxol, from the Pacific yew tree, is used for the treatment of breast, ovarian, and small cell lung cancers.
Xeno Factors and Cancer
Scientists have investigated natural plant products that might inhibit or prevent cancer since long. In these studies researchers demonstrated that a phytoalexin (a polyphenol xeno factor) could interfere with the three major stages of cancer production: it neutralized free radicals as an antioxidant in the initiation stage, acted as an antiinflammatory during the promotion stage, and inhibited the formation of new blood vessels supplying the tumor during the progression stage.
Experts suggest that resveratrol merits further investigation as a cancer chemopreventive agent in humans.
This publication sparked a huge response from other scientists, the media, and the public. Subsequently, hundreds of laboratories have investigated the molecular pathways and biological mechanisms of this and other polyphenols in relation to cancer protection.
Thousands of scientific papers have been published, and companies have been formed to develop these new natural forms of cancer treatment and prevention. Xeno factors are now being evaluated for the treatment of many cancers: prostate, colon, lung, breast, ovary; kidney, liver, pancreas, skin, thyroid, and blood (leukemia). Although extremely complex, these studies support the initial indication that many natural xeno factors can act in potent ways to help prevent cancer. Even more relevant are studies in which xeno factors are tested in live animals and people.
Skin cancers, caused by overexposure to the sun, particularly ultraviolet B radiation, are the most common cancer among humans, In a related animal study to determine whether resveratrol could decrease the damage caused by short-term ultraviolet sun exposure, a single application of resveratrol was placed on the skin of hairless mice. This Significantly blocked the increase in skin thickness and swelling typically seen with acute ultraviolet sun exposure.
There is now reason to believe that the xeno factor resveratrol may be the ultimate natural sunblock for both plants and animals, and may be useful in the treatment and prevention of some skin cancers,
Breast cancer, the most common cancer in women, represents 26 percent of all cancers and causes the death of forty thousand women in the United States each year. In one study, resveratrol was administered to mice by mouth starting seven days before they received a toxic agent that caused mammary cancer, After 69 days of treatment, the incidence of cancer in the mice receiving resveratrol was reduced by approximately 50 percent, The investigators concluded that since resveratrol delayed the occurrence of mammary tumors and suppressed tumor formation at early stages, it might be more effective in the initiation and promotion stage than in the progressive stage.
Prostate cancer is the second most frequently diagnosed cancer, and its incidence increases significantly with men’s age. Several xeno factors found in red grape skins, including catechin, epicatechin, quercetin, and resveratrol, have shown some effectiveness against prostate cancer. Grape skin extract, a rich source of resveratrol and other polyphenols, inhibited prostatic cancer growth up to 98 percent in a study on animals. It also has a direct action on the male hormone androgen, which is known to promote some forms of prostate cancer. Scientists appreciate this effect to the ability of resveratrol to interfere with tumor growth factors in the prostate.
Lung cancer accounts for approximately one-third of all cancer deaths in males and annually kills approximately 115,000 men and 100,000 women worldwide. Environmental factors such as smoking and pollution are the most important causes of lung cancer. As with breast cancer, studies using resveratrol and quercetin demonstrated that both had a significant effect on tumor growth and lung metastasis. In one group of animals, these xeno factors were administered for thirty-two days after implantation of malignant tumors. The results- Tumor growth was inhibited, and the formation of new capillaries at the site of the tumor was markedly reduced. ‘When these xeno factors were administered into the abdominal cavity to treat tumor cells placed there, the compounds reduced tumor volume by 42 percent and metastasis to the lungs by 56 percent .
Colorectal cancer, which is responsible for approximately 10 percent of all U.S. cancer deaths in both men and women, kills approximately fifty thousand people per year. In another animal study, resveratrol was administered via oral fluids for 100 days beginning ten days after administration of a colon cancer-inducing agent. Results suggested a definite protective effect by blocking DNA mutations, by activating immune cells, and by direct action on the genes that controlled cancer-cell: proliferation and progression.
Quercetin has also been studied, and it too showed specific oncogene inhibiting effects.
Liver cancer, which is less common but still fatal in 20000 cases annually, was also investigated. As in the other studies, resveratrol reduced the incidence of solid tumor growth, decreased metastasis, and appeared to be preventive as well.
Further research on resveratrol has shown that it also has promise for treating pancreatic cancer. During studies of malignant human pancreatic cancer cells treated with and without resveratrol, Scientists subjected the cells to ionizing radiation (radiation therapy). Their results were positive in two ways.
First, resveratrol appeared to act as a tumor sensitizer: that is, it made the malignant cells more sensitive to radiation therapy. It also made normal tissue less sensitive to radiation, and this lower sensitivity would help minimize the treatment’s adverse side effects. Second, the researchers believed that resveratrol enhanced the effects of chemotherapy.
Looking at these and other studies, we can come to several conclusions:
• Xeno factors such as resveratrol, quercetin, and other compounds found in red grape skins demonstrate efficacy in preventing cancer in many animal models.
• These molecules block all three mechanisms of cancer formation- initiation, promotion, and progression-through their antioxidant, anti-inflammatory, and antiangiogenic effects.
• Effective treatment and prevention by xeno factors have been demonstrated in animals with cancers of the breast, skin, esophagus, colon, prostate, lung, and liver.
Now we can see why the discovery of these polyphenolic phytochemicals and xenohormesis may be one of the most significant breakthroughs in the prevention of cancer. Xenohormetic molecules from stressed plants-in particular stressed red grape skins-activate our sirtuin enzymes in the absence of caloric restriction but with most of its benefits. Much needs to be learned about the molecular mechanisms by which sirtuin activation is cancer protective, but the hundreds of studies done independently on the sirtuin genes and enzymes and now on xeno factors are converging.
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