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Dec.
9, 2002 |
Clamming for a Cancer Cure
Robert Palazzo, chair of the biology department
at Rensselaer, has solved a twofold problem of collecting and
isolating the tiny centrosome — a little-known structure
of a cell that plays a key role in cell replication.
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| In this micrograph of surf clam oocyte, the
centrosomes are located at the center of the two poles that
appear as a black and white iron cross.
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The solution comes from an unlikely source —
the common surf clam. 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.
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"Many
tumor cells do have more than two centrosomes. 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."
—Robert Palazzo—
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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."
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