DPP-4 inhibitors linked with increased cancer metastasis in mouse study

A class of type 2 diabetes drugs called DPP-4 inhibitors may increase the risk of cancer metastasis according to a study which observed this effect in mice. Metastatsis is where a cancer spreads from one place in the body to another.
Patients on these diabetes medications should not be overly alarmed as these have not shown significantly increased rates of cancer in humans compared to other diabetes drug classes.
In their study, the research team tested the effects of the type 2 diabetes drugs Januvia (sitagliptin) and Onglyza (saxagliptin) along with alpha-lipoic acid. Alpha-lipoic acid is a supplement that is used in some countries to treat diabetic neuropathy, however, it is not commonly prescribed on the NHS.
The mice used in the study were engineered to have a high risk of developing cancer tumours. The study showed that the diabetes drugs did not increase he incidence of tumours developing, however, there was an increase in metastasis of existing tumors associated with the DPP-4 inhibitor drugs.
The researchers investigated NRF2, which is a protein that helps protect cells from oxidative damage which can lead to cancer. As with many proteins in the body, it is beneficial as long as it’s balance is not disturbed.
Some diabetes drugs have antioxidant effects and activate NRF2 which could unsteady the balance of the protein. The researchers hypothesise that by activating NRF2, this may allow certain cancers to migrate.
The researchers state: “It remains to be determined whether these findings will hold up in human patients, but it may be best to exercise caution when giving antioxidant drugs to patients at increased risk for cancer.”
The research team included researchers from the Third Military Medical University, Chongqing, China, the University of Arizona, USA and the University of Heidelberg Medical School, Germany.
The study is published in the Science Translational Medicine journal.