The newspaper said that the experiments conducted on mice with breast tumors revealed that they lived longer after the increased oxygen supply, which sheds new light on the “metastases” or the spread of the disease, as the cells separate from the original site and migrate through the body. This process greatly reduces the chances of a cure and has puzzled experts for decades. Little was known about why these groups of circulating cancer cells (CTCs) left in the first place. Lack of oxygen has now been identified as the driver.
In this context, the lead author of the study, Professor Nicolas Aceto from the University of Basel, Switzerland, said that it provides hope for improving strategies; This may include promoting the formation of blood vessels, which would carry more oxygen. This technique, called neovascularization therapy, worked in rodents. She likened it to the presence of people in a crowded bar or club, struggling to breathe and go out for fresh air.
Aceto’s team analyzed the amount of oxygen inside tumors in animals (such as those seen in humans), separating the cancer stem cells and their biological, molecular and cellular properties. They found different areas with different levels of gas, and cancer cells appeared that lacked oxygen, as blood vessels shrank. This included the core and oceanic regions. The groups that separated and spread out contained less oxygen, indicating that they would leave if they did not get enough of them.
Other tests showed that the oxygen-deprived CTC “crowds” are more dangerous than those with a normal content. They spread faster – and the mice died sooner.
“If the tumor does not have enough oxygen, the CTC groups, which have a particularly high ability to develop metastases, will separate,” Aceto said.
The results, published in Cell Reports, inspired the researchers to stimulate vascular growth in mice with drugs. When they injected it through the tail vein with blood vessels that boosted the protein in the arteries, the oxygen increased in the tumors. As expected, the number of separate CTC groups decreased, the mice formed fewer secondary tumors and the survival rate increased. But at the same time, the primary tumor has significantly increased in size.
“This is a provocative result. If we give the tumor enough oxygen, the cancer cells will have no reason to exit and spread. On the other hand, this speeds up the growth of the primary tumor,” Aceto said.
According to the researcher, the next challenge is to transfer the results to medical clinics, as the characteristics of tumors differ from patient to patient.
Scientists once tried to starve tumors, believing that a more stable blood supply would only help cancer spread.
“We expect that treatments aimed at reducing hypoxia may provide, alone or in combination with anti-cancer agents, a new opportunity to reduce the spread of metastatic cancer in breast cancer patients,” Aceto said.