ALERT: Sleep Apnea Linked to Increased Risk of Deadly Lung Cancer
A new study from the University of Chicago and University of Barcelona revealed that people who are suffering from intermittent hypoxia or an irregular lack of air caused by sleep apnea are more likely to develop advanced and deadly lung cancer.
The study, published in the journal Chest, showed that intermittent hypoxia promotes the release of circulating exosomes, increasing tumor growth. Exosomes are microscopic spheres that play a central role in cell-to-cell communication. They transport proteins, lipids, mRNA and miRNAs between cell. Previous study showed that exosomes are involved in promoting cancer cell growth. Increase in exosomes' numbers or their contents could lead to bigger tumors that metastasize more easily.
"Hypoxia can increase exosomal release and selectively modify exosome contents such as to enhance tumor proliferation and angiogenesis," explained David Gozal, MD, MBA, Department of Pediatrics, Pritzker School of Medicine, The University of Chicago, Chicago, IL and lead investigator of the study, in a press release. "We found the overall concentrations of plasma-isolated exosomes in IH-exposed mice were significantly increased."
For the study, the researchers analyzed the lung cancer tumor cell growth in mouse models. The researchers divided the mice into two groups. The first group experience regular breathing pattern, while the second group were exposed to intermittent hypoxia to stimulate sleep apnea.
The researchers found that mice exposed to intermittent hypoxia have increased numbers of cancer-friendly exosomes, which increases the speed of cancer cell replication and promotes the movement of cancer cells throughout the body. These process disrupts the endothelial barrier, increasing the likelihood of metastasize.
Additionally, the researchers found that exosomes extracted from the mice that were exposed to intermittent hypoxia promoted malignant cell properties in vitro. Furthermore, exosomes from actual patients with sleep apnea showed the same effects on human cancer cells in culture when compared with exosomes from the same patients after treatment of their sleep apnea with CPAP.
Their findings suggests that exosomes released due to sleep apnea may influence the tumor growth in lung cancer, increasing the risk of metastasize and even death.