It’s a well-known fact that controlling one’s calorie consumption is the right way toward a healthier body and mind. New research suggests that reducing calorie intake not only improves longevity, it also helps in restricting certain effects of breast cancer in women. Experiments conducted on mice with triple negative breast cancer (TNBC) revealed that restricting the amount and types of food they were given, significantly reduced the spread of cancer cells.

The study was conducted by the department of Radiation Oncology at Thomas Jefferson University and published in Breast Cancer Research and Treatment. TNBC is quite aggressive and difficult to treat, as the tumors do not express genes responsible for producing certain receptors, which are targeted by chemotherapy. Also, microRNAs 17 and 20 (miR 17/20) have been found to play a crucial part in the metastasis of TNBC.

So, when mice were restricted of their food by 30 percent, the cancer cells produced less miR 17/20. Senior author and associate professor, Dr. Nicole Simone, said in a press release, "The diet turned on a epigenetic program that protected mice from metastatic disease.” 

Most women gain weight after chemotherapy and steroid treatments. The weight may increase further due to hormone therapy. The hormonal shift due to the treatments alters the metabolism, causing the patient to gain up to 10 lbs. in their first year of treatment. Recent research has suggested that cancer treatments may not have a desirable outcome in patients with excess weight, and weight gain during treatment has been known to exacerbate cancer’s spread. "That's why it's important to look at metabolism when treating women with cancer," Simone said in the release.

Some of Simone’s earlier work proved the effectiveness of radiation therapy in inhibiting cancerous cells when coupled with reduced calorie intake. In this study she attempted to understand the molecular pathways that are involved in this effect.

The researchers found that reducing calorie intake while giving radiation therapy to mice had an adverse effect on the production of microRNAs, which in turn resulted in reduced miR 17 and 20. This decrease resulted in increases in the production of proteins necessary for maintaining the extracellular matrix.

"Calorie restriction promotes epigenetic changes in the breast tissue that keep the extracellular matrix strong," Simone said in the release. "A strong matrix creates a sort of cage around the tumor, making it more difficult for cancer cells to escape and spread to new sites in the body."

The researchers believe that focusing miR 17 can be useful for diagnosing cancers that are more likely to metastasize, and for finding potential cures. A drug that directly affects miR 17’s production will have the same effect on the extracellular matrix as calorie restriction does. But since a drug will have the potential to target only a single molecular pathway such as miR 17 it may not be as effective as calorie restriction. 

Also, because TNBC depends on genetic predisposition and tends to be different in different women, calorie restriction may be more effective than drugs in changing the expression patterns of a large set of genes and destroying multiple targets at the same time, without the related toxicity. 

Simone is currently conducting human trials on participants who are part of the CaReFOR (Calorie Restriction for Oncology Research) trial. In a first of its kind approach, women undergoing breast cancer treatment are also getting nutritional advice for weight-loss in order to make their therapies more effective.