2023-08-31 18:04:03
Vitamin C and other antioxidants stimulate the formation of new blood vessels in lung cancer tumors, warns a study published in «The Journal of Clinical Investigation».
The discovery supports the idea that dietary supplements containing antioxidants can accelerate tumor growth and metastasis.
“We have discovered that antioxidants activate a mechanism that causes cancerous tumors to form new blood vessels, which is surprising, since antioxidants were previously thought to have a protective effect,” says the researcher at the Instituto Karolinska (Suecia) Martin Bergö. «New blood vessels nourish tumors and can help them grow and spread».
Antioxidants neutralize oxygen free radicals, which can damage the body, and for this reason they are commonly found in dietary supplements. But too high doses can be harmful.
“Antioxidants in normal foods are not to be feared, but most people don’t need to add supplements,” Bergö says. In fact, she adds, “may be harmful to cancer patients and people at high risk of cancer».
This group had already shown that antioxidants such as vitamin C and E accelerate the growth and spread of lung cancer by stabilizing a protein called BACH1. BACH1 is activated when the level of oxygen free radicals decreases, which occurs, for example, when additional antioxidants are introduced through the diet or when spontaneous mutations in tumor cells activate endogenous antioxidants.
Now the researchers have been able to show that activation of BACH1 induces the formation of new blood vessels (angiogenesis).
Although it is known that low levels of oxygen (hypoxia) are required for the angiogenesis In cancerous tumors, the new mechanism identified by the researchers shows that tumors can also form new blood vessels in the presence of normal oxygen levels.
The study also shows that BACH1 is regulated in a similar way to the HIF-1α protein, a mechanism awarded the 2019 Nobel Prize in Physiology or Medicine that allows cells to adapt to changes in oxygen levels. HIF-1α and BACH1 work together in tumors, new research shows.
Our study opens the door to more effective ways to prevent angiogenesis in tumors
Ting Wang
Instituto Karolinska
“Many clinical trials have evaluated the efficacy of angiogenesis inhibitors, but the results have not been as successful as expected,” says Ting Wang. “Our study opens the door to more effective ways to prevent angiogenesis in tumors; for example, patients whose tumors exhibit high BACH1 levels might benefit more from antiangiogenic therapy than patients with low BACH1 levels.”
The scientists used various cell biology methods and concentrated most of their work on lung cancer tumors by studying organoids, small microtumors cultured from patients.
But they also analyzed mice and human breast and kidney tumor samples.
Tumors in which BACH1 was activated, either by ingesting antioxidants or by overexpression of the BACH1 gene, produced more new blood vessels and were highly sensitive to angiogenesis inhibitors.
“The next step is to examine in detail how oxygen and free radical levels can regulate the BACH1 protein, and we will continue to determine the clinical relevance of our results,” Ting Wang said. We will also carry out similar studies in other forms of cancer, such as breast, kidney, and skin».
#Beware #antioxidants #promote #tumor #growth