Could a study of sea urchins help scientists develop new cancer drugs?
The team showed that the sea urchin’s anatomy is not only physically but genetically analogous to humans’ anatomy.
By SONIA EPSTEINSea urchin skeletons are structurally similar to human blood vessels (Courtesy Haifa University)
Sea urchin skeletons may not be so different from human blood vessels, a new study from the University of Haifa finds, opening doors for cancer drug research and material science.Understanding the mechanism behind the development of sea urchin skeletons provides scientists with a genetic understanding of vertebrate blood-vessel formation, providing new possibilities for cancer researchers seeking to target metastasizing tissue.About 550 million years ago, sea urchins underwent a genetic change that gave them the blueprint they use to build their skeletons. This blueprint is analogous to one vertebrates use for building blood vessels, led by Dr. Smadar Ben-Tabou de-Leon of the Leon H. Charney School of Marine Sciences at Haifa University.The skeletons of these spiny marine creatures develop in tube-like structures: crystallized calcite is surrounded by a membrane, which is surrounded by cytoplasm, which is surrounded by another membrane. To the researchers, this structure was reminiscent of human blood vessels, which have similar tubular structures, but contain blood instead of calcite.The team showed that the sea urchin’s anatomy is not only physically but genetically analogous to humans’ anatomy. They exhibited that a key player in the development of vertebrate blood vessels, the vascular endothelial growth factor (VEGF) signaling pathway, also drives the development of sea urchin skeletons.The researchers injected two kinds of VEGF into the sea urchin larvae: one derived from sea urchins and one derived from humans. Both forms of the protein successfully acted on the skeleton-development process.Additionally, the team found that VEGF activates genes in sea urchin development that are similar to the genes controlling blood-vessel development in vertebrates and humans.For Ben-Tabou de-Leon, the findings present “a beautiful example,” of how a mutation millions of years ago transformed a genetic plan for creating blood vessels into a plan for absorbing minerals and constructing a skeleton.“In evolutionary terms, it seems that it is easier to modify an existing plan than to develop a completely new developmental plan,” she said. Scientists had previously postulated that organisms simultaneously developed different methods for constructing skeletons, rather than inheriting one process from a common ancestor. The team’s new insights into sea urchins’ biomineralization process, or skeleton-building process, lends support to that theory.The findings, recently published in the Proceedings of the National Academy of Sciences journal, could influence the work of scientists researching both material science and cancer drugs.“We would like to be able to fabricate minerals and shape them in the way that we want, but it’s very hard to do that,” Ben-Tabou de-Leon said. Studying how sea urchins build and bend stiff, calcite crystals into exquisite exoskeletons gives material science engineers the potential to harness that molecular power for their own work.In the realm of cancer research, understanding the VEGF pathway is crucial to understanding tumor growth, because VEGF controls the development of new blood vessels. Since blood vessels deliver oxygen to tumors and allow them to metastasize, drug developers could blaze new trails by targeting this pathway to deprive tumors of oxygen.“Our understanding of clinical studies and how molecular networks work comes a lot from developmental studies,” Ben-Tabou de-Leon. “What we did was a major first step, but still a first step.”