Science News - May 5, 2012

proteins in the very chain reaction by which cholesterol and isoprenoids are produced. Prives and Freed-Pastor showed in cell-based experiments that adding a statin substantially impedes this disaster, limiting the ability of mutant p53 to switch on these genes. When the researchers treated breast cancer cells with Zocor in a lab, the cells died or showed slower growth.

There are other biological arguments in the case for statins against cancer. By thwarting isoprenoid production, Lipkin says, statins also disable a process that triggers activation of a proliferation molecule called Ras, which has been implicated in several cancers. Other evidence suggests that starving a tumor cell of cholesterol might slow runaway cell growth because cells use cholesterol as a building block for their fatty membranes.

Several studies have linked high cholesterol with prostate cancer risk, and there is molecular evidence that bottling up HMGCR thwarts this cancer. A 2008 study showed that prostate cancer cell lines exposed to statins are more apt to undergo stalled growth or programmed cell suicide than unexposed cells. “The prostate cancer data actually look pretty strong,” Lipkin says.

Men who underwent prostate removal for cancer were less likely to have a recurrence if they were on statins beforehand than men not getting the drugs, Johns Hopkins University researchers reported last year. While this population finding doesn’t prove cause and effect, “what we’re seeing does make sense in the biological data. It’s nice that it hangs together,” says Alison Mondul, an epidemiologist at the National Cancer Institute who coauthored the study while at Johns Hopkins.

Some say it ain’t so Inflammation and cancer aren’t the only conditions beyond the heart that statins might address. Recent studies suggest that statins might counteract dementia, cataracts, multiple sclerosis, Parkinson’s and depression. A National Institutes of Health website lists hundreds of clinical trials — finished, ongoing or still

25 Cancer blow a recent study shows that statins induced programmed cell death in three prostate cancer cell lines in the lab, suggesting a mechanism underlying the cancer-fighting effect seen in population studies.

Statins versus prostate cancer

100

Percent programmed cell death

control

75

Lovastatin simvastatin

50

0

PC3 Du145

Cancer cell line

source: a. hoque ET AL/CANCER EPIDEMIOL. BIOMARKERS PREV. 2008

LnCap

recruiting participants — that focus on statins’ impact outside of heart disease or stroke. But some scientists remain unconvinced that statins hold more wonder drug potential.

Beatrice Golomb, a physician and neurobiologist at the University of California, San Diego, notes that studies have found some pretty bad side effects associated with statins, including muscle pain and liver damage, as well as perhaps memory loss and diabetes. Such side effects, combined with the widespread prescribing of such drugs, have led to a backlash against statins among some scientists.

Golomb says population studies aren’t nearly adequate to outweigh these doubts. “This is a class of studies that should not be used for causal inferences of a drug and its outcomes,” she says, citing the “healthy-user effect.” People who obtain statins might have better insurance, more education and better access to health care than people who don’t get the drugs, skewing the outcomes.

But physician and epidemiologist Reimar Thomsen of Aarhus University in Denmark says that while the United States does have wide disparities in health coverage, Denmark doesn’t. His population study of statins and pneumonia included people covered by the same health system. “Everyone goes to the hospital for free — funded by taxes,” he says.

Factors such as the variation in
statins’ ability to permeate cell mem-
branes might explain some of the mixed
results seen in recent studies. What’s
more, some patients might be hardwired
to benefit more from statins than others,
Lipkin says. He cites a 2005 population
study that found that colorectal cancer
appears to be vulnerable to statins in
some people but not all.