New Lab Evidence Suggests Preventive Effect Of Herbal Supplement In Prostate Cancer

DHEA is a natural circulating hormone and the body's production of it decreases with age. Men take DHEA as an over-the-counter supplement because it has been suggested that DHEA can reverse aging or have anabolic effects since it can be metabolized in the body to androgens. Increased consumption of dietary isoflavones is associated with a decreased risk of prostate cancer.Red clover (Trifolium pretense) is one source of isoflavones. Both supplements may have hormonal effects in the prostate and little is known about the safety of these supplements.

In a recent report in Cancer Prevention Research, a journal of the American Association for Cancer Research, researchers report that DHEA levels can be manipulated in cells in the laboratory to understand its effects.

Julia Arnold, Ph.D., a staff scientist at the National Center for Complementary and Alternative Medicine (NCCAM) at the National Institutes of Health, said more research is necessary in an environment where men and women concerned about health problems tend to self-prescribe based on information they find on the Internet.

Towards this end, the NCCAM laboratory is studying signaling between human prostate cancer cells and their supporting stromal cells as they grow together in laboratory culture. "DHEA effects in the prostate tissues may depend on how these two cells types 'talk to each other' and further, it may be potentially harmful in tissues containing inflammation or with early cancer lesions because the cells can induce DHEA to become more androgenic," said Arnold.

Combining DHEA with transforming growth factor beta-1 increased testosterone production in the stromal cells and prostate specific antigen protein secretion two to four-fold and gene expression up to 50-fold in the cancer cells. When these cell cultures were treated with red clover isoflavones, the androgenic effects of DHEA were reversed.

"Something is happening in the prostate tissue microenvironment that is illustrating a potential cancer prevention effect from this supplement," said Arnold.

Red clover isoflavones may modify androgenic effects in the prostate but much more work in the laboratory and clinic is needed to validate these effects.

This sort of laboratory manipulation will allow scientists to understand the basic prostate biology as well as learn cellular and molecular mechanisms of over-the-counter supplements and other botanical or herbal agents. Arnold said NCCAM will continue to study DHEA with other supplements to determine any cancer preventive effects.

Catching The Common Cold Virus Genome

A new study by Brigham Young University researchers on the virus behind nearly half of all cold infections explains how and where evolution occurs in the rhinovirus genome and what this means for possible vaccines."There are a lot of different approaches to treating the cold, none of which seem to be effective," said Keith Crandall, professor of biology and co-author of the study. "This is partly because we haven't spent a lot of time studying the virus and its history to see how it's responding to the human immune system and drugs."

The BYU team studied genomic sequences available online and used computer algorithms to estimate how the rhinovirus is related to other viruses.

According to Nicole Lewis-Rogers, a postdoctoral fellow in the Biology Department and lead author on the study, the rhinovirus is similar to the polio virus, whose vaccine was announced in 1955. But while the polio virus has just three subspecies, the rhinovirus has more than 100 subspecies, which continually evolve.

"These viruses could be under the same constraints and yet change differently," Lewis-Rogers said. "That's why it is so hard to create a vaccine."

Through a computer program developed at BYU, Lewis-Rogers' team was able to identify the parts of the virus genome that enable resistance to drugs and the human immune system.

The immune system does a good job of recognizing viral contaminants and getting rid of them, as do new drugs, but the rhinovirus has responded to these defenses by changing its genome so that it is not so easily recognized.

"The virus is evolving solutions against the immune system and drugs," Crandall said. "The more we can learn about how the virus evolves solutions, the better we can rid the body of these infections."

Understanding where change occurs in the virus genome will help virologists who work to design drugs that target the rhinovirus.

"If you've got 10,000 bits of information, this narrows it down to a handful," Lewis-Rogers said. "Here is where you can start looking."

Lewis-Rogers and Crandall hope scientists will use these insights to build better drugs to combat the virus in the most effective way.

The study is reported in the April issue of the journal Molecular Biology and Evolution. BYU undergraduate Matthew Bendall is also a co-author on the study, which was funded by the USDA. Bendall will next pursue a master's in bioinformatics at BYU.

Broccoli May Help Protect Against Respiratory Conditions Like Asthma

Here's another reason to eat your broccoli: UCLA researchers report that a naturally occurring compound found in broccoli and other cruciferous vegetables may help protect against respiratory inflammation that causes conditions like asthma, allergic rhinitis and chronic obstructive pulmonary disease.Published in the March edition of the journal Clinical Immunology, the research shows that sulforaphane, a chemical in broccoli, triggers an increase of antioxidant enzymes in the human airway that offers protection against the onslaught of free radicals that we breathe in every day in polluted air, pollen, diesel exhaust and tobacco smoke. A supercharged form of oxygen, free radicals can cause oxidative tissue damage, which leads to inflammation and respiratory conditions like asthma.

"This is one of the first studies showing that broccoli sprouts — a readily available food source — offered potent biologic effects in stimulating an antioxidant response in humans," said Dr. Marc Riedl, the study's principal investigator and an assistant professor of clinical immunology and allergy at the David Geffen School of Medicine at UCLA.

"We found a two- to three-fold increase in antioxidant enzymes in the nasal airway cells of study participants who had eaten a preparation of broccoli sprouts," Riedl said. "This strategy may offer protection against inflammatory processes and could lead to potential treatments for a variety of respiratory conditions."

The UCLA team worked with 65 volunteers who were given varying oral doses of either broccoli or alfalfa sprout preparations for three days. Broccoli sprouts are the richest natural source of sulforaphane; the alfalfa sprouts, which do not contain the compound, served as a placebo.

Rinses of nasal passages were collected at the beginning and end of the study to assess the gene expression of antioxidant enzymes in cells of the upper airways. Researchers found significant increases of antioxidant enzymes at broccoli sprout doses of 100 grams and higher, compared with the placebo group.

The maximum broccoli sprout dosage of 200 grams generated a 101-percent increase of an antioxidant enzyme called GSTP1 and a 199-percent increase of another key enzyme called NQO1.

"A major advantage of sulforaphane is that it appears to increase a broad array of antioxidant enzymes, which may help the compound's effectiveness in blocking the harmful effects of air pollution," Riedl said.

According to the authors, no serious side effects occurred in study participants receiving broccoli sprouts, demonstrating that this may be an effective, safe antioxidant strategy to help reduce the inflammatory impact of free radicals.

Riedl notes that more research needs to be done to examine the benefits of sulforaphane for specific respiratory conditions. It is too early to recommend a particular dosage.

Riedl recommends including broccoli and other cruciferous vegetables as part of a healthy diet.

The study was supported by the National Institutes of Health, the National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency.

Other study authors include Dr. Andrew Saxon of the Hart and Louis Lyon Laboratory, division of clinical immunology and allergy in the department of medicine at the David Geffen School of Medicine at UCLA, and Dr. David Diaz-Sanchez of the human studies division of the U.S. Environmental Protection Agency.