|
Comment on this article
How cancer spreads
July/August 2008
by Elizabeth Svoboda '03
Since early in his career, John Pawelek, a senior
research scientist at the Yale School of Medicine, has studied melanoma cells.
Now, thanks to an unlikely series of eureka moments, his specialized dermatologic
research has led to sweeping insights about the nature of malignancy itself.
Pawelek and dermatology department colleague Ashok Chakraborty have
demonstrated the workings of the mechanism behind metastasis, the deadly
process by which cancer cells spread to sites all over the body.
| |
Lynn Margulis believes that the cells in our bodies are hybrids of prototype human cells and ancient bacteria.
|
Pawelek's research detour began in the early 1990s,
when a couple of paragraphs in a melanoma journal article by three Czech
scientists caught his eye. "The article asked the theoretical question, 'Is
melanoma metastasis the result of cancer cells fusing with white blood cells?'"
he says. A largely overlooked cell fusion theory of metastasis was actually
first proposed in 1911 by German pathologist Otto Aichel, but the Czech idea
was "an epiphany for me" -- because white blood cells are capable of migrating
throughout the body.
Around the same time, Pawelek's son gave him a book
by evolutionary biology doyenne Lynn Margulis, who believes that the cells in
our bodies are hybrids of prototype human cells and ancient bacteria. Pawelek
was immediately struck by the fact that both Margulis and the journal article
he'd just read were proposing the union of different cell types. "I said to
myself, 'They're saying the same thing.'"
He contacted Margulis, who encouraged him to test the
white blood cell hypothesis post-haste. "She was so excited about it that she
called me at 7:30 on a Sunday morning, even though she didn't really know who I
was," he recalls.
Over the following decade, Pawelek began to explore
the fusion theory in the lab by creating an experimental strain of white blood
cells combined with tumor cells. When he and his colleagues implanted these
hybrid cells into mice, most of the mice quickly acquired metastatic cancer and
died. The team analyzed the molecules used in the artificial hybrid cells to
kick-start the metastasis process. To their surprise, these molecules were
strikingly similar to those produced by naturally occurring human metastatic
cells.
Findings like these, repeated in several
investigations over time and published in the May issue of Nature Reviews
Cancer, confirm
that the fusion theory has passed its first tests with flying colors.
"I think this theory will account for the bulk of
metastasis," Pawelek says. "It will provide a new way of looking at cancer
therapy, because now we have a whole different cancer mechanism to think
about." He plans future studies at bone-marrow transplant centers to document
exactly how white blood cells produced in human bone marrow fuse with the
nuclei of cancer cells.  |