Melanoma, the deadliest form of skin cancer, is responsible for more than 9,000 deaths in the United States per year. The disease often develops as a result of DNA damage caused by exposure to the harmful ultraviolet UVB light from the sun or from indoor tanning.
The problem with existing melanoma drugs that act on single proteins is they are only initially effective. Once the cancer cells' circuitry bypasses the protein that these drugs work on, resistance develops and the disease can recur.
Gavin Robertson, from the Penn State Hershey Melanoma Center, explained that the cancer cells may detour or take other pathways to bypass the closure initiated by existing drugs, much like drivers look for other roads when there is a traffic problem. Robertson and his colleagues are working on a potential solution to this problem, which could pave the way to a potent treatment for melanoma.
For their study published in the journal Molecular Cancer Therapeutics on March 31, Robertson and colleagues looked at 480 natural compounds and found that leelamine, a substance that can be extracted from the bark of pine trees, can potentially shut down protein pathways that allow melanoma cancer cells to multiply and spread.
Leelamine works by disrupting transport of cholesterol around cancer cells. Robertson said that this cholesterol is different from the cholesterol in the blood that causes cardiovascular diseases as this cannot be reduced or targeted with cholesterol-lowering drugs such as Lipitor. Cholesterol in cancer cells is crucial for their survival and since leelamine can shut down cholesterol transport and movement, the cancer cells would die.
"The mechanism of action of leelamine is mediated by disruption of cholesterol transport, causing decreased cellular proliferation and, consequently, leading to increased tumor cell apoptosis as well as decreased tumor vascularization," the researchers wrote.
The researchers have tested leelamine on mice with promising results but further studies are still needed to test the drug on humans.
Skin cancer is the most prevalent type of cancer in the U.S. and melanoma is considered the most dangerous of skin cancers. Individuals who have light skin color, those who have a family history of cancer, and people who are frequently exposed to UV rays have increased risks for skin cancer.
To reduce risks, the Centers for Disease Control and Prevention recommends use of sunscreen, use of clothing and accessories that can provide protection from the harmful rays of the sun, staying in the shade and avoiding indoor tanning.