microRNA Expression Regulates Tumor Growth in Mouse Lung Cancer Model

At 18 weeks of age, mice with overexpressed miR-21 had significantly more tumors than NSCLC animals with normal levels of miR-21. On the other hand, overexpression of miR-21 by itself did not induce cancer formation in otherwise healthy animals.

The investigators determined that at the molecular level miR-21 promoted tumorigenesis by inhibiting tumor suppressors of the Ras/MEK/ERK pathway, which in turn inhibited apoptosis and allowed the cancer cells to grow. Cancer cells growing in mice with no miR-21 expression were more susceptible to certain kinds of chemotherapy, suggesting that inhibiting miR-21 in lung-cancer patients could be of therapeutic value.

"Methods currently exist to pharmacologically manipulate molecules like miR-21,” said senior author Dr. Eric Olson, professor of molecular biology at the University of Texas Southwestern Medical Center. "More research will be needed before we know whether this is applicable to humans, but it's possible that a drug designed to inhibit miR-21 could help keep cancer at bay.”

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University of Texas Southwestern Medical Center