BOSTON--Scientists at Dana-Farber Cancer Institute have uncovered a new role for a key cancer protein, a finding that could pave the way for more-effective radiation treatment of a variety of tumors.
Many cancers are driven in part by elevated levels of cyclin D1, which allow the cells to escape growth controls and proliferate abnormally. In the new research, reported in the June 9 issue of Nature, researchers discovered that cyclin D1 also helps cancer cells to quickly repair DNA damage caused by radiation treatments, making the tumors resistant to the therapy.
Based on this finding, the researchers made cancer cells more sensitive to several cancer drugs and to radiation by using a molecular tool to lower the cancer cells' cyclin D1 levels, said Peter Sicinski, MD, PhD, senior author of the report and a professor of genetics at Dana-Farber.
"This is the first time a cell cycle protein has been shown to be directly involved in DNA repair," said Siwanon Jirawatnotai, PhD, the lead author of the paper. "If we could come up with a strategy to inhibit cyclin D1, it might be very useful in treating a variety of cancers."
The gene for cyclin D1 is the second most-overexpressed gene found in human cancers, including breast cancer, colon cancer, lymphoma, melanoma, and prostate cancer. Cyclin D1's normal function in cellular growth control is to temporarily remove a molecular brake, allowing the cell to manufacture more DNA in preparation for cell division. When cyclin D1 is mutated or is overactivated by external growth signals, the cell may run out of control and proliferate in a malignant fashion.
The findings came in a series of experiments by Jirawatnotai, a post-doctoral fellow in the Sicinski lab. With the goal of uncovering details of cyclin D1's function in human cancer cells, Jirawatnotai broke open four types of cancer cells, isolated the cyclin D1 protein, and searched for other proteins with which it int
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Dana-Farber Cancer Institute