The new mouse: Zebrafish's fluorescent green blood vessels allow cancer researcher to track growth

February 12 2008

TERRE HAUTE • With a small puff of air and a “yep” Mariam Alawoki successfully injected a gene function inhibitor into a zebrafish egg in a move that could be one step closer toward ending tumor growth in humans.

“If we do succeed in what we’re trying to find, it will be a big breakthrough for cancer and anti-angiogenesis research,” said Alawoki, an Indiana State University sophomore life sciences major from Lagos, Nigeria.

Cancer, like any other organ, needs blood. As tumors grow, they stimulate new blood vessels from other existing blood vessels through a process called angiogenesis. Once tumors access the bloodstream, they can grow and spread to other locations within the body in a process called metastasis, which is the most lethal aspect of cancer.

“If we can figure out how to stop blood vessels from growing toward tumors, we might be able to stop tumors from becoming cancer,” Indiana State assistant professor of life sciences Allan Albig said. “It probably isn’t going to kill the tumor altogether, but the idea is that if you can shrink tumors and stop tumors from metastasizing, you can manage the disease, kind of like a diabetic manages diabetes. In the interim, then, the tumor can be treated while it’s in a more or less dormant state.”

While the development of a drug that completely starves tumors by blocking angiogenesis is still years of research away, Albig is working toward that by using zebrafish sent to him by Stephen Ekker from the Mayo Clinic and raising them in ISU life sciences professor Gary Stuart’s fishery.

Albig hopes the specially developed zebrafish with fluorescent green blood vessels will give him a faster start off the blocks in testing the gene function inhibitors. Zebrafish, which are genetically similar to humans, have replaced mice for many researchers.

“The fish is a place where we can do the science quickly and for a fraction of the cost required to do similar experiments in mice,” he said. “To do the same thing on a mouse, essentially a mouse knock-out experiment, you’re probably looking at a year, which will cost lots of money and require highly trained people. In zebrafish, you can get knock-out results in five days or so, for an affordable price, and with graduate or undergraduate students doing much of the work.”

Albig’s research centers upon identifying molecules in extracellular spaces that regulate blood vessel growth and could be converted into anti-angiogenesis or anti-cancer medicines.

Albig and the students are moving through a list of genes to discover which ones are used in blood vessel growth. The fish Albig is using have been genetically altered to have fluorescent green blood vessels, which easily show up under a microscope and help Albig and his team monitor their growth.

“We’ve got a few molecules that we already know are important for angiogenesis, but most of them are essentially just on the blocks, just getting ready to go,” he said.

At Indiana State, the research begins in the fishery amid the hum and gurgle of hundreds of fish tanks with students collecting recently laid eggs that are half the size of a sesame seed.

“Zebrafish like to lay their eggs in the early morning as soon as the sun comes out,” said Kent Williams, a graduate student in life sciences from Evansville. “We’re in a controlled environment; the lights come on at 8:30 a.m.”

After the eggs are poured into one bowl, students then move to the microscope, which helps them to better see the eggs they are injecting with the protein, which is dyed red to aid in seeing if the egg was injected. With the aid of a capillary tube, shaped into an ultrafine needle, and a pneumatic pump to push the protein through the needle and into the eggs, the students set about their morning work.

Since the fish develop quickly, the students only have a few hours to inject each of the eggs.

“Within a day’s time, they’ve already taken on a shape that’s very fish like,” Williams said. “In five days’ time, they’re swimming around.”

Within five days of a female fish laying an egg, an injected baby fish is swimming around with the majority of its blood vessel development completed. Through examining the fish’s fluorescent green blood vessels under a microscope they can easily tell what impact the injection had upon them.

Later the hard work will begin, Albig said. That’s when they attempt to figure out how the protein controls the blood vessel growth.

“That’s a much more time-consuming, much more tedious, much more difficult kind of question to answer,” he said.

Then comes more and varied kinds of testing.

“Just because we find something that might control tumors in fish or in a mouse, that doesn’t necessarily mean it’s going to do anything in the human,” Albig said. “You have to start somewhere.”

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Contact: Allan Albig, Indiana State University, assistant professor of life sciences, may be contacted at 812-237- 8553 or at aalbig@isugw.indstate.edu

Writer: Jennifer Sicking, Indiana State University, assistant director of media relations, at 812-237-7972 or jsicking@indstate.edu

Photo: http://ISUphoto.smugmug.com/photos/253336549_jqevH-D.jpg

Cutline: The top photo shows the normal development of blood vessels in a zebrafish. The middle photo shows where blood vessel growth has been stopped in a zebrafish while the bottom photo shows the stimulated growth of blood vessels. Photos by Allan Albig.

Photo: http://ISUphoto.smugmug.com/photos/251926794_2Qg4A-D.jpg

Cutline: A zebrafish egg is injected with a gene function inhibitor. Photo by Allan Albig.

Photo: http://ISUphoto.smugmug.com/photos/248772288_HQjt3-D.jpg

Cutline: Allan Albig, Indiana State assistant professor of life sciences, examines zebrafish being raised inside a fishery at Indiana State University. Albig uses zebrafish to research gene function inhibitors as a step toward ending tumor growth in humans. Photo by Tony Campbell

Photo: http://ISUphoto.smugmug.com/photos/248773829_CxLWY-D.jpg

Cutline: Mariam Alawoki, an Indiana State University sophomore life sciences major from Nigeria, uses a microscope to inject a zebrafish egg with a gene function inhibitor. Photo by Tony Campbell

Photo: http://ISUphoto.smugmug.com/photos/248769603_V2xFS-D.jpg

Cutline: Kent Williams, an Indiana State University graduate student in life sciences from Evansville, works in the laboratory purifying proteins to use a gene function inhibitors. Photo by Tony Campbell

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Story Highlights

An ISU professor is injecting gene function inhibitor into zebrafish eggs in work attempting to stop blood vessel growth in tumors. By figuring out how to stop blood vessels from growing toward tumors, scientists could be able to stop tumors from becoming cancer.

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