The Academy: May 2007

Published: Thursday, Aug 12, 2010
%u25BA Northwestern University

     Anti-Cancer Flavonoids Synthesized

Chemists at Northwestern University have devised a straightforward method to synthesize flavonoids that have anti-cancer properties. The new method, which utilizes only one simple catalyst, could pave the way for the development of new cancer therapies.

Flavonoids are a family of compounds made of more than 2,000 compounds with different chemical structures that are found abundantly in nature in things such as red wine, dark chocolate and soy. For years, organic chemists have been looking for an effective way to make flavanones, a type of flavonoid, in the lab. They haven’t been successful because of an inherent  complexity of the compounds: flavanones are chiral molecules, which come in two different arrangements that are mirror images of one other, each with very different effects. This is why most therapeutics molecules today that are chiral are made to be either “right-handed” or “left-handed.” A mixture of the two could be potentially dangerous. But so far, it had been hard to synthesize flavanones that were one-handed.

“[Our] work provides for the first time a reliable method for the synthesis of bioactive flavanones in the correct form,” Karl Scheidt, assistant professor of chemistry who led the work told Oncology & Biotech News. “Previous approaches did not solve the issues of chirality of these molecules. Since these compounds in the correct handedness have broad anti-tumor activity, we have provided an important tool in the discovery of new chemotherapies.”

To make their synthetic flavanones, Scheidt’s research team chose to imitate the chemical structures of flavanones in milk thistle, soy, grapefruit, and kosam—a root used in traditional Korean medicine. All of these flavanones are known to be anti-cancerous. The researchers adopted a trial and error process to find a suitable catalyst. After six months of testing more than 30 different catalysts in different conditions, they discovered that a catalyst derived from quinine, when added to other simple materials, created a one-handed molecule like the flavonoids found in nature. The researchers have synthesized 10 different kinds of flavanones; they outline their process in the April 4 issue of the Journal of the American Chemical Society.

Scheidt’s goal is to synthesize molecules that will fight prostate cancer. Some of the synthetic flavanones inhibit the ability of prostate cancer cells to move independently. By selectively modifying the molecules and adding specificity to them, he hopes to create better prostate cancer therapies. “A naturally occurring flavonoid may not have all the characteristics you want—it may not be potent enough, for example—but with chemistry you can go in and modify that structure, imbuing the molecule with more desirable traits, such as binding more effectively to a protein of interest or being less toxic to normal cells,” Scheidt said. “Many of the new medicines for the 21st century will undoubtedly be a direct result of combining the inspiration from natural products with the enabling power of synthetic organic chemistry.”

%u25BA University of Wisconsin - Madison

     Turning the Body's Immune System on Cancer

By  harnessing the body’s natural antibodies and immune responses, researchers at the University of Wisconsin-Madison have developed a way to effectively target and kill cancer cells. In cell-based experiments, the researchers’ system found and killed only the cells that had high levels of receptors known as integrins. Integrins are found on the surfaces of cancer cells and tumor vasculature and are important targets in cancer research. Compared to other tumor-homing agents, the new method did not kill healthy cells that did not express integrins.

A popular method to find tumor cells in the human body is to use cell-binding agents such as monoclonal antibodies, which are attracted to certain receptors found only on tumor cells and not on normal cells. Once the antibody finds the tumor cell, though, it binds strongly to the cell surface. This is not the way things work naturally in the body, said Laura Kiessling, a chemistry professor at UW-Madison, who led the work presented at the annual national American Chemical Society meeting on March 25. In the body, binding agents attach themselves weakly to target receptors. They only stick fast when several receptors are present on the cell surface simultaneously. This helps to reduce false positives, because if the agent mistakenly finds and adheres to a healthy cell, it can be easily displaced.

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Cancer Summaries and Commentaries™: Update from Atlanta: Advances in the Treatment of Chronic Lymphocytic LeukemiaFeb 28, 20190.5
Community Practice Connections™: 2nd Annual International Congress on Immunotherapies in Cancer™: Focus on Practice-Changing ApplicationFeb 28, 20192.0
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