Herbal substance protects against chemo

Healthy cells could be protected against chemotherapeutic agents by herbal agents

08/04/2014

Depending on the type of cancer and the stage of the disease, chemotherapy is a standard cancer therapy. The patient is given chemotherapeutic agents that are intended to destroy cancer cells. However, a particularly unpleasant effect of these drugs for those affected is that they attack not only diseased cells but also healthy, rapidly dividing tissue. Therefore, many patients suffer from side effects such as hair loss and nausea.

Researchers at the German Cancer Research Center (DKFZ) have recently discovered a herbal compound that could protect healthy cells from the toxicity of chemotherapeutics while at the same time not reducing the damaging effect on cancer cells. The active ingredient is called "Rocaglamide", is purely vegetable and has been used for many years in Chinese medicine.

Herbal active ingredient rocaglamide could make chemotherapy more compatible
By discovering the protective effect of Rocaglamide on healthy cells, cancer therapy could become better tolerated for many patients in the future, writes the DKFZ in a statement. But further investigations are necessary.

Most chemotherapeutic agents cause damage to the DNA of rapidly dividing cells. This affects both cancer cells and healthy tissue. Drugs that exert their toxic effects only on degenerate, malignant cells, there is hardly any. In addition, it is not known whether these agents - unintentionally - also protect the cancer cells from the toxicity of the chemotherapeutic agents.

Many cancer patients suffer from hair loss during chemotherapy because they attack the hair follicle cells, nausea and vomiting as they damage the lining of the stomach and intestines, and other unpleasant, harmful side effects. That's why scientists have been looking for new drugs for a long time, which on the one hand protect healthy cells and on the other destroy cancer cells. „Rocaglamide was one of many herbal substances that we tested“, reports Min Li-Weber from the DKFZ, who led the study. „The active ingredient is derived from herbs and used for many years in Chinese medicine, for example against inflammation.“

The more herbal active ingredient, the greater the protection of healthy cells from chemotherapeutic agents
In the study, the researchers treated white blood cells from healthy donors with various chemotherapeutic agents. In addition, Rocaglamide was added in different concentrations. „The higher the amount of Rocaglamide, the more white blood cells have survived“, explains Li-Weber. However, according to DKFZ, the herbal active substance had no influence on the survival rate of the cancer cell lines used.

To find out if rocaglamide can prevent DNA damage to healthy cells, the researchers performed a comparison of cells, part of which was treated with the chemo-therapeutics and the drug and the other part with the chemo-treatment alone. „The damage was almost identical“, reports Michael Becker, first author of the study „This means, on the one hand, that rocaglamide does not directly prevent the effect of the chemotherapeutic agents. On the other hand, it also means that the drug itself does not cause DNA damage.“

Herbal ingredient blocks formation of protein
Further investigations showed that rocaglamide prevents the formation of the protein p53, which is also known as „Guardian of the genome“ and produced by cells with damaged DNA. The protein triggers above a certain limit the so-called programmed cell death, so that the cell dies. „Rocaglamide thus prevents healthy cells from forming the protein p53 after contact with a chemotherapeutic agent, thus activating programmed cell death“, Becker explains. „And because p53 is missing or defective in about half of all cancers in the cancer cells, rocaglamide did not affect the cancer cells in our tests.“ This would allow cancer patients without p53 in the tumors to benefit from the drug since rocaglamide would then protect only the healthy cells from the toxic effects of the chemotherapeutic agents. „Numerous experiments in other laboratories have shown that a short-term blocking of p53 does not lead to an increased risk of cancer“, Becker continues. „Whether this also applies to Rocaglamid, we want to find out next.“ The researcher has already put forward a hypothesis: „It could be that the cells have more time to repair their DNA damage.“

DKFZ celebrates 50 years of German cancer research
The DKFZ was founded in 1964 in Heidelberg. Since then, scientists have been researching new drugs, improved therapies and the mechanisms of cancer. On the occasion of the 50th anniversary of the DKFZ, CEO Otmar D. Wiestler pointed out the Center's great successes: „We are particularly proud of the successes of my predecessor Harald zur Hausen: his discovery that cervical cancer is caused by papillomaviruses was the basis for the development of a vaccine that will protect women from this serious disease in the future. This research was rightly crowned with the Nobel Prize.“ Also in the research of tumor stem cells, which was only established at the DKFZ in 2008, Wiestler reports that results will soon be available. (Ag)