Lung cancer culprit could offer target for therapy, researchers report

DALLAS – Sept. 13, 2010 – A tiny molecule that spurs the progression of non-small-cell lung cancer could become a player in fighting the disease, say researchers at UT Southwestern Medical Center, who published a study on how the molecule behaves in mice in the Sept. 14 issue of Cancer Cell.

Scientists have known that the molecule microRNA-21, or miR-21, is present in overabundant quantities in human tumors, including non-small-cell lung cancer (NSCLC). Until now, however, it was unclear whether miR-21 contributed to the development of lung cancer, or whether it was simply an indicator of the presence of the disease.

	Findings by Drs. Eric Olson (left) and Mark Hatley indicate that overproducing the miR-21 molecule does not trigger lung cancer in rodents, but it does make it worse.

To find out, lead study author Dr. Mark Hatley, an instructor of pediatric hematology/oncology, and UT Southwestern colleagues used mice that had been altered specifically to harbor non-small-cell lung cancer. In some of these mice, they genetically engineered the animals to produce too much miR-21. In another group, they deleted the miR-21 gene altogether, which eliminated the molecule in the rodents.

In animals with cancer, the results showed that too much miR-21, or overexpression, promotes the formation, growth and survival of new tumors by turning off certain genes that normally allow cancer cells to die. In fact, at 18 weeks of age, the study group with overexpressed miR-21 had significantly more tumors than their lung-cancer-carrying littermates with normal levels of miR-21. Healthy rodents engineered to overexpress miR-21 did not develop cancer.