In this micrograph of a surf clam oocyte, the centrosomes are located at the center of the two poles that appear as a black-and-white iron cross.

Clamming for a Cancer Cure

Robert Palazzo, professor and chair of biology, has solved a twofold problem with the help of the common surf clam. His work focuses on collecting and isolating the tiny centrosome — a little-known structure of a cell that plays a key role in cell replication. Palazzo’s research into the mechanisms of these minute structures could lead to new therapeutic cancer drugs.

In the mid-1980s, Palazzo found a source of centrosomes in the unfertilized eggs of the surf clam. He now has developed methods to isolate centrosomes on a large scale to study how they martial chromosomes to divide within a cell. Abnormal division of chromosomes is one theory of how cancer cells arise.

Each summer, Palazzo collects billions of clam eggs on the shallow ocean floor in Woods Hole, Mass., where he conducts centrosome research nearby at the Marine Biological Laboratory.

Scientists know the basic role of the centrosome is to organize the contents of a cell before and after cell replication begins. But because of its tiny size, one-tenth that of the average nucleus, researchers have had little luck in isolating enough of them to analyze the molecular mechanisms that control their function.

A healthy cell duplicates its original centrosome to establish two new cell centers, and to guide the movement of the cell’s chromosomes. When the centrosomes are in place, each set of chromosome pairs is split and the sister chromosomes move toward their respective centrosome to complete mitosis (cell division).

If a cell generates more than two centrosomes, however, the chromosomes could be disproportionately distributed to the new cells. This would result in abnormal numbers of chromosomes and genetic instability.

“In fact, many tumor cells do have more than two centrosomes,” Palazzo says. “The next step, therefore, is to find a way to prevent abnormal centrosome replication or prevent centrosome function in those tumor cells while minimizing damage to normally functioning cells in the same tissue.”