SAN FRANCISCO, July 5 (Xinhua) -- U.S. researchers are exploring the potential of an Food and Drug Administration (FDA)-approved drug for certain cancers to treat smoke-induced chronic obstructive pulmonary disease (COPD) that makes breathing difficult.

They found plerixafor, a drug used in stem cell therapy to treat certain cancers, may function as a protection against emphysema, a form of progressive lung disease resulting from many yeas of cigarette smoking, according to a study by American Physiological Society released Thursday.

Plerixafor is a medication that stimulates the immune system to release more of a type of stem cell, hematopoietic progenitor cells (HPCs), from the bone marrow into the bloodstream. It is used to treat cancers originating in the blood cells.

As stem cells have the potential to develop into different kinds of cells in the body and are capable of tissue repair, the researchers explored the effect of plerixafor on stem cell circulation and lung function in mice.

According to their observation, a group of mice exposed to cigarette smoke five days a week for 22 weeks recorded a decreased number of HPC populations in the bone marrow.

In contrast, the other group of mice that were exposed to the same amount of cigarette smoke but received regular treatment of plerixafor reported a greater amount of HPCs and showed no remarkable increase in the level of white blood cells, an indicator of illness.

The study supports the protective effects of plerixafor on smoke-induced lung injury as greater bone marrow mobilization expands HPC presence that helps lung cell repair.

The findings of the study were published ahead of print in the American Journal of Physiology -- Lung Cellular and Molecular Physiology.?