Broccolis, the vegetable that
most mothers have to tell their children to finish at least once in their life
may contain potential superpowers involved in the suppression of tumors or
cancerous cells. Researchers have recently discovered that eating cruciferous
vegetables or plants of the cabbage family such as broccoli, cauliflower and watercress
helps prevent the cancerous cells in your body from being switched on.
According to current research and data, epigenetics plays an important role in
suppressing the harmful carcinogenic cells in an individual’s body. Epigenetics
refer to the study of how heritable gene expressions derived from environmental
factors and do not involve the alterations of the underlying primary DNA
sequence. This branch of science plays an important role in the
study of diseases and health issues as it explains how an individual’s diet,
habits and other environmental factors have the ability to alter or switch “on”
and “off” gene expressions.
Sulforaphane (SFN), a chemical
compound found in cruciferous vegetables is the factor responsible in
preventing cancer through the complex process of epigenetics. Researchers
of Clinical Epigenetics (Hsu et al. 2011) conducted a research
titled “Promoter
de-methylation of cyclin D2 by sulforaphane in prostate cancer cells” in an attempt to discover how the chemical
components of cruciferous vegetables epigenetically alter our gene expressions to
inhibit cancer.
Scientists have recently discovered that the
chemical compound sulforaphane alters gene expression through an epigenetic
process by acting as a dietary histone deacetylases (HDAC) inhibitor, a family
of enzymes that interferes with the normal function of genes that suppress tumors.
This chemical compound has been shown to do many significant tasks that helps
regulate gene expression in breast cancer, gastric cancer, colon cancer, etc. The
aim of this research is to evaluate the effects of SFN on epigenetic regulation
of cyclin D2 in prostate cancer cells. Firstly, let’s clarify some complicated terminologies.
Cyclin D2 is a family of protein that is known to regulate the progression of
cell cycle, mainly in the G1 and S phase of the cycle. If under any
circumstances the protein malfunctions, it could induce the abnormal growth of
bodily tissues. According to the research, Cyclin D2 has been identified in
several cancer cases as a proto-oncogene. Any over-expression or
under expression of the protein can bring about several types of cancer. DNA-methylation
is “a normal process of turning off genes, and it helps
control what DNA material gets read as part of genetic communication within
cells”. In addition, the results of the experiment indicate
that SFN is also capable of suppressing DNA methyltransferases (DNMTs), a type
of enzyme that controls the regulation of the gene expressions of cancerous
cells.
In
order to conduct the experiment, researchers utilized cells that were cultured
and treated in laboratories. The three types of cells used include benign
prostate hyperplasia (BPH-1) cells, androgen dependent prostate cancer
epithelial cells (LnCap) and androgen-independent prostate cancer epithelial
cells (PC3). Benign prostate hyperplasia cells refers to the enlargement of the
prostate gland common in elderly men, while androgen prostate cancer epithelial
cells are cells found along the body’s cavities that stimulates the development
and maintenance of male characteristics. After being treated with various chemicals,
the DNA sequence of each cell was amplified using quantitative polymerase chain
reaction. This type of PCR enables both detection and quantification of DNA
sequence. A series of diluted copies of the DNA sequence served as the standard
or benchmark for quantification. Next, researchers used what is known as the
western blot analysis, which is an analytical technique used to detect specific
proteins in a given sample of tissue.
After various treatments were applied to all cell types, data points were collected and statistical
difference between SFN treated cells and other treatments were determined and found
that the difference of results were statistically significant with a P value of
less than 0.05. During the experiment, the effects of SFN on the expressions of
DNMTs (DNMT1, DNMT3a and DNMT3b) were
tested BPH-1, LnCap and PC3 prostate cancer cells as mentioned before.
Cells were treated with different amounts of sulforaphane (15 um and 30 um) and
were tested for the DNMTs after 48 hours. Results of the experiment as presented
in the diagram above show that both doses of sulforaphane significantly
decreased DNMT1 and 3b mRNA expression. In LnCap cells, SFN
also decreased mRNA expressions of DNMT1
and 3b and DNMT1 protein expression.
Moreover, the experiment showed that sulforaphane decreased Cyclin D2 promoter
methylation.
As previously mentioned, DNA
methylation is the process of regulating gene expression by turning “on” and
“off” specific genes. A tightly regulated balance
exists in normal cells among these processes, but disruption of this balance
contributes to the development of cancer. Basically, what it comes down to is
that ingesting food products with SFN can prevent this malfunctioning of normal
cells as recent studies have shown that SFN contain chemo-preventative
properties such as HDAC and DMNT inhibitors. According to Emily Ho, an associate professor in the Linus Pauling, “DNA methylation
is a natural process, and when properly controlled is helpful. But when the
balance gets mixed up it can cause havoc, and that's where some of these
critical nutrients are involved. They help restore the balance." Findings of
this experiment provide promising insights into how sulforaphane (SFN) is
capable of epigenetically altering gene expression to prevent prostate cancer.
Credits:
- "Eat Your Broccoli: Another Mechanism Discovered by Which Sulforaphane Prevents Cancer." ScienceDaily. ScienceDaily, 28 Feb. 2012. Web. 30 Apr. 2012. <http://www.sciencedaily.com/releases/2012/02/120228140555.htm>.
- "Epigenetics: DNA Isn’t Everything." ScienceDaily. ScienceDaily, 12 Apr. 2009. Web. 30 Apr. 2012. <http://www.sciencedaily.com/releases/2009/04/090412081315.htm>.
- Hsu et al.: Promoter de-methylation of cyclin D2 by sulforaphane in prostate cancer cells. Clinical Epigenetics 2011 3:3/
- "Broccoli Fights Cancer by Clearing Bad Tumor Suppressors: Scientific American Podcast." Science News, Articles and Information. Web. 30 Apr. 2012. <http://www.scientificamerican.com/podcast/episode.cfm?id=broccoli-fights-cancer-by-clearing-11-01-27>.
- "How Broccoli Fights Cancer." Discovery News. Web. 30 Apr. 2012. <http://news.discovery.com/human/how-broccoli-fights-cancer-110310.html>.
- "Breasts, Broccoli and Cancer." Alternative & Natural Cancer Treatments-Cancer Treatment Alternatives Options-. Web. 30 Apr. 2012. <http://www.anoasisofhealing.com/breasts-broccoli-and-cancer>.
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ReplyDeleteYour blog was really informative and enjoyable to read, and after reading your blog, I learned more not only about broccoli and cancer, but also about epigenetics, which my topic, Alzheimer’s disease, is related to. When I conducted my own research, I originally thought that epigenetics could be influenced by our external environment only when we’re exposed to toxic substances which pervade our systems without us knowing it or being able to do anything about it. However, after reading your blog, I realized that epigenetics is far more easily influenced than that. To think that by simply eating broccoli and other plants of the cabbage family, one can inhibit enzymes that interfere with the function of tumor suppressing genes! By identifying the one miraculous chemical compound, Sulforaphane, scientists were able to find a way to stop cancer before it even affects people, which is truly great because it prevents people from having to go through the pain of chemotherapy or other cancer therapies which don’t even guarantee a full recovery. In the case of Alzheimer’s disease, scientists have yet to glean such useful information, having only recently discovered that epigenetics plays a role in causing the disease. However, I’m quite sure that one day we will be able to prevent or even cure Alzheimer’s disease as well, because even with such a deadly disease as cancer, we were able to make this much progress.
ReplyDeleteI also saw that the research study you chose utilized PCR in order to detect, quantify, and amplify the DNA sequences of each cell. This approach to analyzing DNA sequences was quite different from that used in the research study I chose, in that mine did not use PCR and instead used the brain tissue of deceased subjects. However, by using PCR so you could see the specific genes which you’re interested in, you are able to get a more precise picture than if you just tested for DNA methylation in general. These different methods for gaining information show the complexity of the scientific field of research—in order to test certain things, one must decide which of many different available approaches to take.
Although I would enjoy eating broccoli, a huge portion of children still detest it. So, using future technology, scientists might be able to discover the exact protein or enzyme that produces sulforaphane (SFN). After knowing the proteins that form this chemical, future scientist could go deeper into which hormones signal the protein to begin working and even deeper into the genetic sequence/fragments that forms the hormone and enzyme. Once all of these have been discovered, we might be able to extract this sequence, or even make this sequence from nothing, and splice it into a more worldwide common food source such as wheat and rice. All of these steps will be quite difficult, but one day if cancer research hits a stop where we cannot cure some of the most complicated cancerous cells, the SFN in the future that can be found in wheat could be what will save our lives.
ReplyDeleteThis article is very imformative and interesting to read. When it is said that the genetic disease can be prevented by a certain food, it becomes really interesting. I have been worried about getting cancers in my later life, but now i can prevent it by eatting broccolis or other cruciferous vegetables. However, i was confused at a point where it says a dietary histone deacetylases inhibitor is a family of enzymes that interferes with the normal function of genes that suppress tumors. If the genes suppress tumors, why is it interfered? Besides, i really enjoyed the details about the experiments that researchers conducted with cells.
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