According to Wikipedia (October 5, 2011), hERG (the human Ether-à-go-go Related Gene) is a gene (KCNH2) that codes for a protein known as Kv11.1 potassium ion channel. This ion channel (sometimes simply denoted as 'hERG') is best known for its contribution to the electrical activity of the heart that coordinates the heart's beating (i.e., the hERG channel mediates the repolarizing IKr current in the cardiac action potential). When this channel's ability to conduct electrical current across the cell membrane is inhibited or compromised, either by application of drugs or by rare mutations in some families, it can result in a potentially fatal disorder called long QT syndrome; a number of clinically successful drugs in the market have had the tendency to inhibit hERG, and create a concomitant risk of sudden death, as an unwanted side effect, which has made hERG inhibition an important antitarget which must be avoided during drug development. therapeutic agents that can increase I(Kr)and are useful for LQT syndrome.
In the other words, hERG potassium channels are essential for normal electrical activity in the heart. Changes in the hERG gene lead to a long QT syndrome. LQT syndrome is a disorder causing arrhythmias. Arrhythmia can also be induced by certain drugs, hERG channels blockers. This unwanted effect is a common reason to cause drug failure in preclinical safety studies.
Picard S. (not Enterprise Captain Picard) and his group from Université de Caen,France, pointed out that almost all medicines withdrawn from the market because of life-threatening tachyarrhythmias (torsades-de-pointes) were hERG blockers and QT interval delayers.
Recently, Jehle J from Medical University Hospital, Germany, and co-workers reported that hERG K(+) channels are also expressed in a variety of cancer cells where they control cell proliferation and apoptosis. Thus, hERG K(+) channels may be a drug target in anticancer therapy.
