Blood Pressure Drugs May Fight Lung Cancer

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Rather than testing ACE inhibitors themselves, the researchers injected half the mice with the angiotensin (1-7) hormone for a 28-day treatment period. The remaining mice received saline.

The experiment stimulated blood levels of angiotensin (1-7) in the mice to concentrations equivalent to those found in humans being treated with ACE inhibitors.

Subsequent dissections revealed that cox-2 levels diminished significantly in the treated mice, while lung tumors shrank by 30 percent. In contrast, tumors in mice receiving the saline solution grew to 2.5 times their pre-treatment size.

Gallagher and her colleagues uncovered no evidence of toxic side effects among the angiotensin (1-7) mice. The rodents displayed no apparent changes in body weight, heart rate or blood pressure, the researchers said.

They pointed out that negative side effects are a big concern, given that a class of drugs known as cox-2 inhibitors (which include Celebrex and the now-banned Vioxx and Bextra) have also been shown to reduce lung cancer risk. However, studies suggest that those drugs may carry an increased risk for cardiovascular complications such as heart attack, angina and stroke.

The authors said further study was needed to establish if higher doses of angiotensin (1-7) might be tolerated, or whether longer treatment periods might promote even more tumor reduction.

Gallagher said human trials are set to begin within two weeks. She added that if the current findings pan out, hormone-boosting drugs such as ACE inhibitors could ultimately play a significant role in lung cancer care, either as a stand-alone intervention or as part of a multi-pronged effort to combat the disease.

"One thing, too, we're hoping, is that we'll be able to apply these drugs in combination with other current therapies, so we can reduce the amount of chemotherapies being used," she said, "because, of course, chemotherapy has such toxic side effects. So, maybe in a combined cocktail, we'll be able to really improve people's quality of life."