Selumetinib

The Ras-Raf-MEK-ERK signaling cascade is known to be activated in several types of cancer, and regulates the transcription of proteins involved in apoptosis. In addition, studies have shown that mutations of the Raf component of the pathway can contribute to chemotherapy drug resistance.

Ras as well as several kinases and phosphatases are responsible for regulating the Raf-MEK-ERK pathway. Often in cancers, Ras (a G-protein coupled receptor) is deregulated, allowing downstream signalling to proceed unchecked. Through several complex steps, Raf phosphorylates and activates MEK, which then phosphorylates and activates ERK. ERK is then able to exert its effects on several downstream targets.

As such, therapies inhibiting upstream components of this pathway have become attractive targets for cancer treatment. Selumetinib exerts its effects by selectively inhibiting MEK1 and MEK2 which can effectively blunt the pleiotropic effects of the Ras-Raf-MEK-ERK cascade. By inhibiting this oncogenic pathway, selumetinib reduces cell proliferation, and promotes pro-apoptotic signal transduction.