While it may seem common knowledge that smoking is bad for your lungs, if and how ultrafine particles present in cigarette smoke impact the development and progression of lung cancer remains unclear. Working with animal models, researchers at Baylor College of Medicine sought to find how airborne ultrafine particles in smoke can change a host’s defense against lung cancer.
In a study published in the current edition of Science Advances, Dr. Cheng-Yen Chang, a postdoctoral fellow in Dr. Farrah Kheradmand’s lab in the Department of Medicine — Pulmonary at Baylor, and their team discovered that exposure to ultrafine particles alters the function of immune cells in the lungs, disabling their natural defense mechanism against tumors. They found that ultrafine particles change the cell’s primary energy source, creating new byproducts in the lungs. Accumulation of the new byproducts can decrease the host’s immune defense, allowing tumors to escape detection.
These particles are not just found in cigarette smoke; environmental and other natural fires also incompletely combust organic matter that generates ultrafine particles. Kheradmand and colleagues at Rice University had previously found that immune cells in the lungs of heavy smokers contain particles that they identified as nano-sized elemental carbon black.
“When we breathe, we inhale many particles of different sizes. They are lodged somewhere along the airways, like in the nose or trachea, depending on their size.”
“Ultrafine particles are so small they can navigate the respiratory system and deposit in the far distal part of the lung that is used for gas exchange — the process of breathing,” Kheradmand said. “It is at that point where these particles can collect and begin to alter the way lung immune cells function.”
The study illuminates how ultrafine particles promote cancer progression
Using two different mouse models of lung cancer, Chang was able to replicate the same type of exposure to ultrafine particles typically seen in a heavy smoker.
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