Deep Blue Sea - Renny Harlin

A businessman sinks $200 million into a special project to help fight Alzheimer's disease. As part of this project, medical biologist Susan McAlester rather naughtily figures out a way to genetically enlarge shark brains, so that disease-battling enzymes can be harvested. However, the shark subjects become super smart and decide they don't much like being cooped up in pens and being stabbed with hypodermics, so they figure a way to break out and make for the open sea...