Karen Handel, the former Susan G. Komen for the Cure executive at the center of last year's public clash with Planned Parenthood, says she'll be running for an open U.S. Senate seat in Georgia.

Handel's announcement Friday shakes up an already crowded contest among Republicans vying for the seat held by U.S. Sen. Saxby Chambliss, who is retiring next year. Three of Georgia's Republican congressmen have announced plans to run.

Handel, a former secretary of state, narrowly lost the GOP primary for governor in 2010 and is expected to tap quickly into her statewide network of supporters. Handel was a top Komen executive when the charity announced plans to cut off funding for Planned Parenthood. It later reversed course amid a public outcry, and Handel resigned earning support from conservatives.

Tags: Karen Handel, Jack Kingston, Saxby Chambliss, Paul Broun, elections, Phil Gingrey, 2014 election, senate race