passages.id: split_4_test_1172_passage
passages.type: progene_text
passages.text: Transient transfection of a constitutively active PI3 - kinase or an inducible Akt promoted myoblast viability in the absence of growth factors , while inhibition of PI3 - kinase activity by the drug LY294002 selectively blocked IGF - but not PDGF - mediated muscle cell survival .