Drugs from the deep: Ocean bioprospecting

By Emily Rose Nelson, RJD Intern

Oceans cover over 70% of the earth’s surface. Some of the greatest biological diversity in the world is found in the seas. Over 200,000 species of invertebrates and algae have been identified, and this number is estimated to be only a small fraction of what is yet to be discovered. This immense biodiversity yields great chemical diversity. When working with potential pharmaceuticals this becomes extremely important, more chemically diverse substances are more suitable. The field of marine natural products is just over 40 years old and already over 15,000 chemical compounds have been identified as having biological function.

Many of these chemicals have cancer fighting potential. Many sessile organisms emit chemicals to prevent others from evading their space. Often times these chemicals are used to slow and prevent cell growth of surrounding sponges, etc. It is believed that the same chemicals these organisms let out when competing for space can be used to stop the uncontrolled division of cancer cells. Cancer treatment compounds have advanced quite a bit due to funding from the National Cancer Institute. Discodermolide is a polypeptide isolated from deep water sponges (Discodermia). This substance stops the reproduction of cancer cells by disrupting the microtubule network (partially responsible for movement of cells). Bryostatin, a substance released by some bryozoans, is believed to be particularly useful against leukemia and melanoma. The Caribbean mangrove tunicate produces a compound (Ecteinascidin-743 or ET-743) that has been tested in humans for the treatment of breast and ovarian cancers and found to be effective.

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