Cell Culture: Human embryonic kidney (HEK-293t) cells and Chinese Hamster Ovary (CHO) cells were provided graciously by the Ren Lab at Carnegie Mellon University. Human Cervical Cancer (HeLa) cells were graciously provided by the Wayne Lab at Carnegie Mellon University. A549, MDA-MB-231, and RAW264.7 cells were obtained from the American Type Culture Collection (ATCC). All cell lines, except CHO, were cultured with DMEM supplemented with 10% FBS and Antibiotic-Antimycotic. CHO cells were cultured in F12/DMEM (1:1) supplemented with 10% FBS and Antibiotic-Antimycotic. The cells were kept in a 100% humified atmosphere containing 5% CO2 at 37˚C. ATCC protocols were followed for culturing and handling.