Compounds in broccoli, cauliflower, and watercress
block lung cancer progression.
FEB, 2008 zhion@zhion.com
A family of compounds found in cruciferous vegetables,
such as broccoli, cauliflower, and watercress, blocked
lung cancer progression in both animal studies and in
tests with human lung cancer cells.
Chemoprevention is regarded as one of the most promising
and realistic approaches in the prevention of human cancer.
Among naturally occurring products, sulfur-containing
compounds, especially garlic compounds and isothiocyanates,
represent two important and promising chemopreventive
families because of their potent chemopreventive effects in
various in vivo and in vitro models. In recent years, numerous
investigations have shown that sulfur-containing compounds
induce apoptosis in multiple cell lines and experimental
animals. [2]
What is Isothiocyanates?
Isothiocyanates are sulfur-containing compounds which are
largely responsible for the typical flavor of cruciferous
vegetables. In animals including humans they are conjugated
with glutathione; the first product of this reaction is a
dithiocarbamate, which can be ultimately metabolized to the
corresponding mercapturic acid, excreted in urine. [1]
What is the benefits of isothiocyanates or veggie diets?
Epidemiological studies on the relationship between cancer risk
with isothiocyanate intake or excretion have shown inverse
associations, mainly with lung cancer. The studies are also
consistent in reporting a gene-environment interaction, with a
stronger protective effect in persons null for the GSTM1 or
GSTT1 genotype. [1]
Recent study has shown its benefits on lung cancer.
The study's principal investigator Fung-Lung Chung, Ph.D.,
say the results, published in a set of papers in the September
15 issue of Cancer Research, suggest that these chemicals
— put into a veggie pill of sorts — might some day be used
to help current and former smokers ward off development of
lung cancer, the leading cause of cancer death in Americans.
One of the two new studies being reported was the first to
test whether these compounds, derived from naturally
occurring isothiocyanates, could have an impact on the stages
of cancer development specifically after exposure to cancer-
causing elements . To test that, the researchers induced lung
tumor development in experimental mice by exposing them to
tobacco carcinogens, and then they fed one group of mice the
veggie compounds. They found that, indeed, use of the
chemicals resulted in a reduced development of benign
(harmless) lung tumors to malignant tumors, compared to
mice that did not receive the compound.
The second new study looked at the effect of the same
compound on human lung cancer cells, which were forced to
grow quickly (as cancer does) because of insertion of a gene
known to be involved in cell growth and regulation. The
laboratory test showed that the derivative of isothiocyanate
significantly pushed the human lung cells to commit “suicide,
” compared to cells that did not have the gene, suggesting
that its use may stop fast growing lung cancer cells from the
outset. This study provides some insight onto “one of the
possible mechanisms of action” by which the compounds
may offer some protection against lung cancer development,
the researchers said.
These studies were continuation of a 20-year research effort
by Chung and his team, much of it conducted while Chung
was at the Institute for Cancer Prevention before moving to
Georgetown University Medical Center. The body of research
they have established on the connection between cruciferous
vegetables and lung cancer is one of the most detailed
available.
The study was funded by a grant from the National Institutes
of Health.
REFERENCES
[1] Bianchini F and Vainio H Isothiocyanates in cancer prevention. Drug Metab
Rev. 2004 Oct;36(3-4):655-67.[2] Wu X, Kassie F, and Mersch-Sundermann
V, Induction of apoptosis in tumor cells by naturally occurring sulfur-containing
compounds. Mutat Res. 2005 Mar;589(2):81-102. Epub 2005 Jan 4. [3] Laura
Cavender, Compounds Found in Veggies Can Block Lung Cancer Progression in
Experimental Studies, Georgetown University Medical Center , Press Release,
September 15, 2005
