Cancer Drugs to Fight Obesity?

By: Matt Weik
IML Research Blog

It doesn’t happen often, but every once in a while, when researchers are investigating one piece of data, they come to discover something else that could be groundbreaking. When researchers at a Mayo Clinic were running cancer studies on mice, they discovered that the drugs used in the study were also causing considerable weight loss in the mice.  So, what does this mean when changing directions and looking at obesity as well?

Two Birds (or mice) with One Stone?

When the researchers were giving their experimental mice two “common cancer-fighting drugs” they realized that the obese mice they were using for the study lost a considerable amount of weight fairly quickly even when still consuming a diet high in fat and without any caloric constraints put in place. This is interesting as it appears that the drugs have a way of altering metabolic mechanisms.

Could this be the magic pill that everyone has been looking for where you can continue to be lazy, yet take a drug and lose weight without any effort or changes in diet or lifestyle habits?

One researcher stated, “We were surprised to observe that when morbidly obese mice were treated with certain cancer-fighting drugs, the drugs not only targeted their cancers, but also tended to spontaneously resolve their obesity—even with undiminished gorging on a high-fat diet.” The other researcher working on this study mentioned, “Two chemotherapy agents—methotrexate and cyclophosphamide—could be dosed to completely reverse obesity without detectable toxicity, even in mice without cancer.  Interestingly, these drugs are already used to treat some noncancerous conditions, such as rheumatoid arthritis.”  The immunologist in the study said, “The ease with which this weight loss was achieved in mice—even with continued caloric binging—is in stark contrast to the Herculean difficulties morbidly obese patients experience trying to preserve weight loss through dietary restraint.”

The researchers are trying to figure out exactly where the calories went in the body if they weren’t getting stored as fat. It is their belief that the excess calories might be going to the liver.  Their thought process on this was that through the cancer treatment, the drugs helped the liver process the excess calories.  The immunologist again stated, “Based on our composite data, it appears that methotrexate or cyclophosphamide can induce the livers of obese mice to burn off rather than accumulate excessive dietary fat. This results in desirable weight reduction instead of increased obesity, even with continued caloric binging.”

The finding at the Mayo Clinic is extremely intriguing as not only do the two drugs used for cancer help treat cancer itself, but now it might be a way for morbidly obese individuals to lose weight and get back down to a healthy range. Obviously, the research found here is using rodents rather than human subjects, therefore, more research needs to be done to see if the study yields the same results on humans.  But, this leaves the door open for what could be an amazing discovery.

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Sources: Cheryl E. Myers, Dominique B. Hoelzinger, Tiffany N. Truong, Lindsey A. Chew, Arpita Myles, Leena Chaudhuri, Jan B. Egan, Jun Liu, Sandra J. Gendler, Peter A. Cohen. Chemotherapy can induce weight normalization of morbidly obese mice despite undiminished ingestion of high fat diet. Oncotarget, 2017; DOI: 10.18632/oncotarget.14576  Mayo Clinic. “Researchers find cancer-fighting drugs help morbidly obese mice lose weight.” ScienceDaily. ScienceDaily, 17 January 2017. <>.