Tag: copper

Categories : Metabolic DisordersTags : Leave a comment

Metformin Found to Change Blood Metal Levels in Humans

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Although metformin is the most widely prescribed diabetes drug in the world, its mechanism of action is still not clear. Kobe University endocrinologist OGAWA Wataru has now made significant progress, finding that it changes blood metal levels in humans. Photo by Towfiqu Barbhuiya on Unsplash

The widely used diabetes drug metformin may achieve its effects by changing blood metal levels in humans. The Kobe University study is an important step in understanding the drug’s many actions and designing better ones in the future.

Metformin is the most widely prescribed diabetes drug in the world. Apart from lowering blood sugar levels, it is also known to have a broad range of beneficial side effects such as against tumours, inflammations and atherosclerosis. However, although it has been used for more than 60 years now, its mechanism of action is still not clear, hampering the development of even better drugs against these conditions.

Kobe University endocrinologist OGAWA Wataru says: “It is known that diabetes patients experience changes in the blood levels of metals such as copper, iron and zinc. In addition, chemical studies found that metformin has the ability to bind certain metals, such as copper, and recent studies showed that it is this binding ability that might be responsible for some of the drug’s beneficial effects. So, we wanted to know whether metformin actually affects blood metal levels in humans, which had not been clarified.” To do so, Ogawa and his team enlisted about 200 diabetes patients at Kobe University Hospital, half of which took metformin and half of which did not, in a study to analyse their blood serum levels for those metals and various metal deficiency indicators.

In the journal BMJ Open Diabetes Research & Care, the Kobe University team now published the first clinical evidence of altered blood metal levels in patients taking metformin. They showed that drug-taking patients have significantly lower copper and iron levels and heightened zinc levels. Ogawa says: “It is significant that we could show this in humans. Furthermore, since decreases in copper and iron concentrations and an increase in zinc concentration are all considered to be associated with improved glucose tolerance and prevention of complications, these changes may indeed be related to metformin’s action.”

Recently, Japan has approved the use of imeglimin, a new diabetes drug that is a derivative of metformin but that should not be able to bind metals the same way as its parent. “Imeglimin is thought to have a different method of action, and we are already conducting studies to compare the effects the two drugs have,” says Ogawa.

It is not just about understanding the current drugs, however. Ogawa explains the bigger picture, saying: “We need both clinical trials and animal experiments to pinpoint the causal relationship between the drug’s action and its effects. If such studies progress further, they may lead to the development of new drugs for diabetes and its complications by properly adjusting the metal concentrations in the body.”

Source: Kobe University

Categories : Cancer New Compounds and TreatmentsTags :

New Therapy Approach Robs Cancer Cells of their Vital Copper

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© Wiley-VCH, Credit: Angewandte Chemie

While toxic in high concentrations, copper is essential to life as a trace element. Many tumours require significantly more copper than healthy cells for growth – something which new cancer treatments might exploit this. In the journal Angewandte Chemie, a research team from the Max Planck Institute for Polymer Research has now introduced a novel method by which copper is effectively removed from tumours cells, killing them.

Copper is an essential cofactor for a variety of enzymes that play a role in the growth and development of cells. For example, copper ions are involved in antioxidant defence. Cells very strictly regulate the concentration and availability of copper ions. On the one hand, enough copper ions must be on hand; on the other, the concentration of free copper ions in the cytoplasm must be kept very low to avoid undesired side effects. Extracellular, doubly charged copper ions are reduced to singly charged copper, transported into the cell, stored in pools, and transferred to the biomolecules that require them on demand. To maintain the cellular copper equilibrium (homeostasis), cells have developed clever trafficking systems that use a variety of transporters, ligands, chaperones (proteins that help other complex proteins to fold correctly), and co-chaperones.

Because cancer cells grow and multiply much more rapidly, they have a significantly higher need for copper ions. Restricting their access to copper ions could be a new therapeutic approach. The problem is that it has so far not been possible to develop drugs that bind copper ions with sufficient affinity to “take them away” from copper-binding biomolecules.

In cooperation with the Stanford University School of Medicine (Stanford/CA, USA) and Goethe University Frankfurt/Main (Germany), Tanja Weil, Director of the Max Planck Institute for Polymer Research (Mainz) and her team have now successfully developed such a system. At the heart of their system are the copper-binding domains of the chaperone Atox1. The team attached a component to this peptide that promotes its uptake into tumour cells. An additional component ensures that the individual peptide molecules aggregate into nanofibres once they are inside the tumour cells. In this form, the fibre surfaces have many copper-binding sites in the right spatial orientation to be able to grasp copper ions from three sides with thiol groups (chelate complex). The affinity of these nanofibres for copper is so high that they also grab onto copper ions in the presence of copper-binding biomolecules. This drains the copper pools in the cells and deactivates the biomolecules that require copper. As a consequence, the redox equilibrium of the tumour cell is disturbed, leading to an increase in oxidative stress, which kills the tumour cell. In experiments carried out on cell cultures under special conditions, over 85% of a breast cancer cell culture died off after 72 hours while no cytotoxicity was observed for a healthy cell culture.

The research team hopes that some years in the future, these fundamental experiments will perhaps result in the development of useful methods for treating cancer.

Source: Wiley