PIK-75 blocks production of PIP2 and/or PIP3, phosphorylation of Akt, and activation of mTORC1 in adipocytes and myotubes. PI 3-kinase (PI3K) catalyzes the synthesis of the second messengers PtdIns-(3)-P, PtdIns-(3,4)-P2, and PtdIns-(3,4,5)-P3. The PI 3-kinase family of enzymes is comprised of 15 members that are divided into three classes according to their structure, substrate specificity, and mode of regulation. In the class I PI 3-kinases, p110α is the primary PI 3-kinase isoform required for insulin signaling in adipocytes and myotubes and is frequently mutated in primary tumors. Small molecule inhibitors of p110α are of interest in cancer treatment research. PIK-75 is an imidazopyridine that selectively inhibits p110α with an IC50 value of 5.8 nM. PIK-75 inhibits p110γ and p110β considerably less effectively.
