LY294002 is a potent inhibitor of class I phosphoinositide 3-kinases (PI3Ks) [1, 2]. It is cell permeable and reversible, and selective against p110α, p110β, p110γ and p110δ, which acts on ATP binding site of the catalytic subunit.

PI3K family is divided into 3 classes: class I, II and III. LY294002 can inhibit 3 out of 4 isoforms of catalytic subunit of class I group. The IC50s for p110α, β andδ are 500 nM, 973 nM and 570 nM [3]. Even though it is less potent than wortmannin, other PI3K inhibitor, but it is more stable in solution. In addition, LY294002 is a reversible inhibitor whereas wortmannin acts irreversibly. [2]

PI3Ks signal through Akt, activates mTOR and inhibits Bad, leading to cell growth and proliferation. LY294002 potently inactivates PI3K class I catalytic subunit, resulting in induction of apoptosis and suppression of tumor cell growth in vitro and in vivo. [2, 4]

LY294002 is also a potent autophagy inhibitor by blocking autophagosome formation. [5]

Quantitative chemoproteomic profiling shows that LY294002 inhibits the BET bromodomain proteins BRD2, BRD3, and BRD4 with IC50 value of 1-2 μM. [6]