After several weeks of clearance sales, the RadioShack store at Cabin John Shopping Center closed its doors on Monday as the company prepared for a likely bankruptcy filing. Several retailers are rumored to be interested in taking over empty RadioShack stores — including Sprint Corp. and Amazon, which is looking to open storefronts where customers can drop off and pick up their online orders. The RadioShack locations on Rockville Pike and at Westfield Montgomery Mall are still in business… for now.