Spring Break
Small proteins mark blood vessel growth in solid tumors
Issue date: 9/25/08
Large-scale growth of blood vessels, what biologists call angiogenesis, is usually a bad sign. The unstructured growth and differentiation of new blood vessels often signifies the presence of a tumor, which requires a tremendous blood supply to bring it nutrients and oxygen.
Some cancer treatments work by blocking angiogenesis and subsequently starving the malignant tissue, an idea first introduced in the 1970s. But how does one halt the juggernaut of gargantuan, spontaneous vascular networks whose sole purpose for existence is feeding a cancerous tumor?
Hopkins researchers Emmanouil Karagiannis and Aleksander Popel, both from the biomedical engineering department, have addressed that question in a recent paper published in the Proceedings of the National Academy of Sciences on Sept. 16.
Their research focuses on developing methods for the identification of peptides - short proteins - that thwart the creation and mobility of endothelial cells which line blood vessels.
"In the current work, we have applied [a computational algorithm] in order to identify antiangiogenic peptides - peptides that inhibit the proliferation and migration of endothelial cells," Karagiannis said.
"During the last 30 years, approximately 40 peptides that inhibit angiogenesis have been identified. The way that those peptides were identified was through a time-consuming, low-yield and expensive methodology. Whole proteins that the investigators were thinking that they may regulate angiogenesis were processed experimentally with various enzymes, the proteases, that cleave proteins in smaller fragments and later these small fragments were screened for activity."
The methodology addressed by Karagiannis and Popel is computational, meaning it relies on heavy use of data processing rather than work in the laboratory. Part of this method uses information from BLAST, the Basic Local Alignment Search Tool, a free computer program that is available on the National Institutes of Health's website. Two other calculations, called the Smith-Waterman algorithm and a Monte Carlo filter, comb through this data to find bioactive peptides that can be as long as 25 amino acids.
Some cancer treatments work by blocking angiogenesis and subsequently starving the malignant tissue, an idea first introduced in the 1970s. But how does one halt the juggernaut of gargantuan, spontaneous vascular networks whose sole purpose for existence is feeding a cancerous tumor?
Hopkins researchers Emmanouil Karagiannis and Aleksander Popel, both from the biomedical engineering department, have addressed that question in a recent paper published in the Proceedings of the National Academy of Sciences on Sept. 16.
Their research focuses on developing methods for the identification of peptides - short proteins - that thwart the creation and mobility of endothelial cells which line blood vessels.
"In the current work, we have applied [a computational algorithm] in order to identify antiangiogenic peptides - peptides that inhibit the proliferation and migration of endothelial cells," Karagiannis said.
"During the last 30 years, approximately 40 peptides that inhibit angiogenesis have been identified. The way that those peptides were identified was through a time-consuming, low-yield and expensive methodology. Whole proteins that the investigators were thinking that they may regulate angiogenesis were processed experimentally with various enzymes, the proteases, that cleave proteins in smaller fragments and later these small fragments were screened for activity."
The methodology addressed by Karagiannis and Popel is computational, meaning it relies on heavy use of data processing rather than work in the laboratory. Part of this method uses information from BLAST, the Basic Local Alignment Search Tool, a free computer program that is available on the National Institutes of Health's website. Two other calculations, called the Smith-Waterman algorithm and a Monte Carlo filter, comb through this data to find bioactive peptides that can be as long as 25 amino acids.
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