The hormone that regulates the circadian cycle, melatonin, may help slow the growth of certain breast cancers, according to a study published in the journal PLOS One.
Scientists at the Henry Ford Hospital in Detroit, USA, in collaboration with the Foundation for Research in Sao Paulo (FAPESP), investigated the effects of melatonin on angiogenesis and the development of triple-negative breast cancer – both in cultured cells and in an animal model.
Angiogenesis, i.e. the process of blood vessel formation, plays a very important role in the course of neoplastic processes. The formation of vessels within tumors promotes their growth, as well as infiltration and metastasis.
Mice were treated with melatonin for 21 days. The drug was administered one hour before the lights were turned off. Melatonin is believed to be more effective when given before it enters the night mode as the tissues are then more susceptible to the effects of the hormone.
After 21 days, scientists conducted SPECT (Single Photon Emission Tomography) studies to see if the treatment affected the size of human cancer cells implanted in mice, and the process of blood vessel formation.
During the course of treatment, none of the treated mice lost weight or fell into a state of lethargy; on the contrary – they were more mobile without showing any irritability or aggression.
A reduction in tumor size was observed in the treated rodents, while in the control group the tumor size increased significantly. Fewer blood vessels have also formed in the area of the tumor. Similar results were obtained during tests on the cells themselves. (PAP)