Tel Aviv University researchers have discovered the mechanism by which melanoma metastasizes: The tumor releases vesicles filled with microRNA, a process that can be targeted with drugs.
According to the American Cancer Society, melanoma makes up only 1% of all skin cancer cases, but it causes the majority of skin cancer deaths.
"The threat of melanoma is not in the initial tumor that appears on the skin, but rather in its metastasis--in the tumor cells sent off to colonize in vital organs like the brain, lungs, liver and bones," said Dr. Carmit Levy of the Department of Human Molecular Genetics and Biochemistry at Tel Aviv University’s Sackler School of Medicine in a statement. "We have discovered how the cancer spreads to distant organs and found ways to stop the process before the metastatic stage."
It was previously known that melanomas develop in the epidermis, the outermost layer of skin. Early-stage melanoma is unable to metastasize because it has no blood vessels and no access to the body’s blood vessels, including some in the dermis. Levy’s team set out to uncover how the tumors eventually make this connection.
"We found that even before the cancer itself invades the dermis, it sends out tiny vesicles containing molecules of microRNA," Dr. Levy said. "These induce the morphological changes in the dermis in preparation for receiving and transporting the cancer cells. It then became clear to us that by blocking the vesicles, we might be able to stop the disease altogether."
The scientists sought chemicals to attack this process and landed on two: SB202190 inhibits the delivery of the vesicles from the tumor to the dermis, while U0126 wards off the changes in the dermis even after the vesicles have been released, according to the statement. Both tested well in the lab and could lead to potential drug candidates against the cancer.
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