Definition

An orally bioavailable, small molecule inhibitor of class I phosphoinositide 3-kinase (PI3K) isoforms and mammalian target of rapamycin kinase (mTOR), with potential anti-fibrotic, anti-inflammatory and antineoplastic activities. Upon oral administration, PI3K/mTOR inhibitor HEC 68498 targets and inhibits class I PI3K isoforms and mTOR kinase. This disrupts phosphorylation of substrates downstream of PI3K and mTOR and may result in apoptosis and growth inhibition in susceptible tumor cells and may inhibit inflammation and fibrosis. The PI3K/mTOR pathway is upregulated in a variety of tumor cells and plays a key role in promoting cancer cell proliferation, survival, motility and resistance to chemotherapy and radiotherapy. It also plays a key role in inflammation and fibrosis. mTOR, a serine/threonine kinase downstream of PI3K, may also be activated in a PI3K-independent fashion; therefore, this agent may be more potent than an agent that inhibits either PI3K or mTOR alone.