Text / Li Luming
“The Atlantic” magazine once published a pair of 38-year-old identical twins – Monica and Erica’s story. In September 2015, Monica had intermediate stage breast cancer that had spread to the lymph nodes. Erica, however, had regular mammograms and ultrasounds, and no cancer cells were found. The twins have the same genes, why does one get cancer and the other doesn’t?
We have always believed that genes (DNA) determine everything regarding us. In fact, there is another key factor, which is the “switch” of genes. For example, genes determine that the twins have the same necklace, but the genetic switch determines whether he “wears” or “don’t wear it,” “when to wear it,” and “for how long.” The key to determining the on and off of this gene is the epigenetic factor.
Everyone’s DNA is fixed. The moment the sperm and egg fuse, the DNA is set. There are regarding 200 types of cells in the body, but each type of cell actually has the same DNA.
However, through the command of epigenetic factors, the same DNA can make different cells, such as heart cells, liver cells, etc. Again, the differences between these cells are enormous. Likewise, it can also promote the production or non-production of cancer cells.
There are regarding 50 trillion cells in the human body, and each cell contains regarding 180 centimeters of DNA. Such long pieces of DNA can fit into the nucleus of a cell because they choose to wrap around.
The shafts around which DNA is wound, we call histones. A single piece of DNA is wound around 30 million of these spools. The circular axes represent histones, and the lines around them are DNA (such as the DNA epigenetic mechanism diagram).
Epigenetic factors can bind to the “tails” of histones, or they can bind to DNA. Epigenetic factors (methyl groups) that stick to DNA can directly “turn off” genes.
Epigenetic factors also control how DNA wraps around histones. It allows genes to wrap tightly around histone proteins in a compressed state. At this point, gene expression is inhibited, the human body cannot read this part of the gene, and the gene is in a “off” state.
It also loosens DNA threads that are wrapped around histone spools. The unbound DNA is freed from inhibition, and the human body can read these opened DNA messages, that is, the gene is in an “on” state.
Changes in epigenetic factors may ultimately determine whether a person suffers from a certain disease. For example, if the epigenetic factor is turned off and the gene for a protein that suppresses cancer cannot be expressed, so that the protein is no longer produced, the tumor will grow. But the gene, if left turned on, might prevent tumors from developing.
You can’t change your genes. So, how can we turn on good genes and turn off bad genes, so that cancer does not occur?
Diet, tobacco and alcohol, drugs, psychological stress, and living environment will all affect epigenetic factors. They affect genes mainly in two ways – DNA methylation and histone modification.
A growing body of research is finding that diet is a key to controlling gene expression. A methyl group is an epigenetic factor that can enter cells through diet, and when it is marked on DNA, it is called DNA methylation.
Methyl groups can turn off genes. In normal cells, oncogenes are turned off by methyl groups and remain silent; tumor suppressor genes are not methylated, they are turned on. In cancer cells, the opposite is true.
Another way, histone modification, has a similar reason.
In short, when you eat foods that are beneficial for anti-cancer, no matter which way you affect genes, the ultimate purpose of their action is the same: “Turn off oncogenes and turn on tumor suppressor genes.”
these foods alter gene expression
1.Catechin
Teas are rich in catechins, of which green tea is the most abundant. Catechins are tea polyphenols, which are the most abundant bioactive compounds in green tea, accounting for more than 50% of the active compounds in green tea, and their anticancer effects have been widely studied.
The anticancer properties of catechins lie in their ability to block the methylation of tumor suppressor genes. Once these genes are hypermethylated, they become inactive and cannot play a role in suppressing cancer.
Ingestion of catechins can protect the activity of beneficial genes, so that cells can produce anti-cancer proteins to achieve the effect of resisting and treating cancer.
A study by researchers at the University of New Jersey, published in Cancer Research, demonstrated that catechins in green tea can inhibit DNA methylation and restart cancer in human colorectal, skin, esophageal, and prostate cancer cells. A tumor suppressor gene that was silenced by hypermethylation.
Another study, published in the journal Carcinogenesis, showed that catechins have the same regulatory effect on DNA methylation in skin cancer cells.
In addition, a large number of studies have proved that the intake of catechins has a significant inhibitory effect on cancer cells in the oral cavity, breast, stomach, ovary, and pancreas.
2. Resveratrol
Resveratrol is a plant polyphenol naturally present in grape skins. Fruits such as mulberries, cranberries, blueberries, and peanuts also contain resveratrol.
Resveratrol has antioxidant, anti-inflammatory and anticancer properties, and has effects on the control of cell division, growth and apoptosis, and cancer cell metastasis. The anti-proliferative properties of resveratrol have been validated in liver, skin, breast, prostate, lung and colorectal cancer cells.
Researchers at the University of Arizona found that resveratrol prevents epigenetic silencing of tumor suppressor proteins in breast cancer cells.
Scientists at the National Institutes of Health have experimentally confirmed that resveratrol can inhibit the expression of anti-apoptotic proteins in breast cancer cells, thereby inducing cancer cell apoptosis. Therefore, these researchers believe that resveratrol is an excellent choice for targeted therapy of breast cancer.
3. Isoflavones
Many people are not unfamiliar with soy isoflavones in soybeans and soy products. It is a kind of isoflavones. Isoflavones are also present in foods such as broad beans and kudzu.
Soy isoflavones are phytoestrogens. Its anticancer and anticancer properties are reflected in its effects on histone modifications and DNA methylation, thereby regulating gene transcription.
Studies have shown that soy isoflavones can restart the expression of tumor suppressor genes in prostate cancer cells. It has also been found that soy isoflavones and other isoflavones can modulate the expression of noncoding RNAs in several cancer cells.
Researchers at the University of Missouri conducted human anticancer trials using soy isoflavones. Genetic changes were assessed in 34 healthy postmenopausal women taking either 40 mg or 140 mg of isoflavones daily.
The results showed that taking isoflavones hypermethylated two breast cancer-related genes, which silenced these breast cancer genes.
4. Isothiocyanates
Isothiocyanate is a dietary fiber found in cruciferous vegetables (including broccoli, cabbage, cabbage, etc.). It inhibits cancer cell growth and exhibits the ability to promote cancer cell apoptosis.
Human experiments at Oregon State University show that eating 68 grams of broccoli can effectively inhibit the activity of histone deacetylase in peripheral blood mononuclear cells, thereby achieving the effect of preventing cancer.
In addition, researchers from another university in the United States have shown through cell culture that isothiocyanates can inhibit methyltransferase in breast cancer cells and inhibit the hTERT gene that is overexpressed in regarding 90% of cancers. .
In addition, there are various nutrients that can control and treat cancer. A review in the journal Epigenomics concluded that the following nutrients and foods can alter epigenetic factors in two ways:
Foods that fight cancer by modulating DNA methylation:
Selenium (Brazil Nut), Isothiocyanate (Broccoli), Catechin (Green Tea), Resveratrol (Grape), Isoflavones (Soybean).
Foods that fight cancer by modulating histone modifications:
Isoflavones (Soybean), Curcumin (Curry), Catechin (Green Tea), Resveratrol (Grape), Isothiocyanate (Croccoli), Selenium (Brazil Nut), Allyl Mercaptan (Garlic) . ◇