27 May 2014

A low-calorie diet increases the effectiveness of cancer treatment

It is believed that following a balanced low-calorie diet can increase life expectancy. According to the results obtained by researchers at Thomas Jefferson University, such a diet can have other positive effects. One of them is to increase the effectiveness of breast cancer therapy.

According to the head of the study, Associate Professor Nicole Simone, a low-calorie diet triggers an epigenetic program that prevents metastasis. Experiments on a mouse model of thrice-negative breast cancer (one of the most aggressive forms of the disease) demonstrated that when animals were kept on a diet whose caloric content was 30% lower than the number of calories received by mice with unlimited access to food, the production of microRNA–17/20 decreased in malignant cells (microRNA is a type of RNA that regulates expression genes through epigenetic modifications of DNA.). The level of these molecules often increases with the metastasis of thrice-negative breast cancer.

Breast cancer patients often receive hormone therapy that blocks tumor growth and steroid medications to neutralize the side effects of chemotherapy. However, this can disrupt metabolism and lead to an increase in body weight. Recent studies have shown that the appearance of overweight in women reduces the effectiveness of standard breast cancer therapy and worsens the prognosis of the disease.

In earlier studies, the authors demonstrated that a low-calorie diet increases the effectiveness of antitumor radiotherapy. The aim of their latest work was to elucidate the molecular mechanisms underlying this phenomenon.

Experiments on mice have shown that during radiotherapy on the background of a low-calorie diet, the production of certain types of microRNAs, especially microRNA-17/20, sharply decreases in malignant tumor cells. This decrease, in turn, stimulates the synthesis of proteins that ensure the maintenance of a good state of the extracellular matrix. A fully functioning extracellular matrix forms a kind of capsule around the tumor, which makes it difficult for malignant cells to enter the bloodstream and spread through the body.

The identification of this mechanism has provided specialists with a new molecular target for the diagnosis of cancer prone to metastasis and, possibly, for the development of new antitumor drugs. Theoretically, a drug that suppresses the synthesis of microRNA-17/20 will have the same effect on the extracellular matrix as a low-calorie diet.

Currently, researchers are inviting patients with triple–negative breast cancer to participate in the CaReFOR clinical trial (from the English Calorie Restriction for Oncology Research - a low-calorie diet for cancer research). As part of the study, women undergoing radiotherapy for breast cancer treatment will simultaneously receive dietary recommendations aimed at reducing body weight. The aim of the study is to confirm the hypothesis formulated by the authors.

Article by L. Jin et al. The metastatic potential of triple-negative breast cancer is reduced via caloric restriction-mediated reduction of the miR-17~92 cluster is published in the journal Breast Cancer Research and Treatment.

Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Medical Xpress: Fighting cancer with dietary changes.


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