Researchers at the University of East Anglia have completed several years work to find a compound that seems to block the movement of the pigment cells that give tadpoles their unique markings. Uncontrolled movement of pigment cells has been linked to cancer in both humans and frogs, which means skin cancer detection and prevention could be improved.
Melanoma cells in particular, are known to migrate (or move) through the body to the organs, causing secondary tumors that are one of the more high-risk forms of cancer.
Melanomas are one of the most dangerous types of skin cancer because they’re both invasive and resistant to treatment.
Malignant melanoma is responsible for 75% of all skin cancer deaths, and about 160,000 new cases (over 62,000 in the U.S.) of melanoma are diagnosed worldwide each year.
If research can learn how to block this process, perhaps cancer spread can be delayed or even halted altogether.
Despite the hopeful outlook, practical applications in terms of medications are likely still years away.
The compound used in this study was selected from 3,000, screened to see if they effected the pigment cells. The compound, known as NSC 84093, produced a visible change in the color markings on the tadpoles when used in very low concentrations. The continuous stripe along the back was replaced by a pattern of blocks of color along the back of the tadpole.
Biologist and lead researcher Grant Wheeler at the University of East Anglia said, “Forty of the compounds gave us an interesting difference which we wanted to follow up.”
Apparently its easy to look at the tadpole embryos and see the color change — so many compounds could be tested.
A chemist at the University saw that the structure of the compound they were using had properties that showed it could bind to a zinc molecule. A substance expressed by melanoma tumors, matrix metaloproteinases (MMP) thought to be involved with cell behavior such as migration, is zinc dependent.
The compound identified by the British researchers keeps the MMP from doing what comes naturally. The team saw changes to patterning on the tadpoles depending on the strength of the dose given.
And if you’re wondering what tadpoles can tell us about cancer, it helps to understand how much we have in common with the little critters. These simple creatures diverged from man a mere 360 million years ago, though they still have the same organs, molecules and physiology as we do.
This tells us that cancers in the frogs will develop and act just as they do in people.
What’s more, the tadpole that becomes the South African Clawed Frog, produces eggs all year round so supplies of subjects are plentiful.
The intriguing study appears in the January 2009 journal Chemistry & Biology and though there is still a lot of work to be done, if these preliminary results hold, we may be one step close to finding an effective skin cancer detection process and treatment for one of many invasive forms of cancer. The next step is to test the compound in other animals.