When that early step is blocked by 50 percent or more, a cell produces substantially less cholesterol. A fraction is siphoned off and used as molecular bolts to attach special signaling proteins to cell membranes. Statins not only reduce the supply of cholesterol, they also reduce the supply of isoprenoids. That, in turn, has a cascade of effects on the signals a cell sends to other cells, and to itself. They reduce the inflammation in plaques that makes them more likely to burst open and precipitate a heart attack.
Statins also alter the immune system in subtle ways.
Curiously, the drugs also trigger suicide in some cancer cells, including one type of leukemia, cervical cancer, and several tumors of children. So far, the anti-cancer effect has been seen only in laboratory studies, and only when cells are exposed to a drug at doses far higher than what people take to lower cholesterol. Studies are underway testing the safety of high-dose statin treatment in cancer patients. But the excitement is that because statins are on the market, we can fast-track their testing, unlike many of the other novel cancer drugs coming down the line. Not every once-touted action of the drugs has panned out.