Washington, Mar 2: A new study, conducted on mice, has found that compounds extracted from green vegetables like broccoli and cabbage could be a potent drug against melanoma, a type of skin cancer.

The study found that these compounds, when combined with selenium, target tumours more safely and effectively than conventional therapy.

"There are currently no drugs to target the proteins that trigger melanoma," said Gavin Robertson, associate professor of pharmacology, pathology and dermatology, Penn State College of Medicine.

"We have developed drugs from naturally occurring compounds that can inhibit the growth of tumours in mice by 50 to 60 percent with a very low dose," Robertson added.

Robertson and his colleagues previously showed the therapeutic potential of targeting the Akt3 protein in inhibiting the development of melanoma.

The search for a drug to block the protein led them to a class of compounds called isothiocyanates. These naturally occurring chemicals found in cruciferous vegetables are known to have certain cancer-fighting properties.

However, the potency of these compounds is so low that a successful drug would require large impractical amounts of these compounds. Instead, the Penn State researchers rewired the compounds by replacing their sulfur bonds with selenium.

The researchers believe that the result is a more potent drug that can be delivered intravenously in low doses.

"Selenium deficiency is common in cancer patients, including those diagnosed with metastatic melanoma. Besides, selenium is known to destabilize Akt proteins in prostate cancer cells," said Robertson

To study the effectiveness of the new drug, isoselenocyanate, researchers injected mice with 10 million cancer cells.

After six days, when the animals developed large tumours, they were divided into two groups and treated separately with either the vegetable compounds or the compounds supplemented with selenium.

"We found that the selenium-enhanced compounds significantly reduced the production of Akt3 protein and shut down its signaling network," said Robertson.

The modified compounds also reduced the growth of tumours by 60 percent, compared to the vegetable-based compounds alone.

When the researchers exposed three different human melanoma cell lines to the two compounds, the selenium-enhanced drug worked better on some cell lines than others. The efficiency was from 30 to 70 percent depending on the cell line.

The findings appear in the March edition of Clinical Cancer Research. (ANI)