When the space shuttle
Discovery blasts off on its next mission (scheduled Aug. 9), it will take
ovarian cancer into space for the first time.

Part of a joint project between University of South Florida
College of Medicine and the National Aeronautics and Space Administration,
the ovarian cancer cells are headed to the International Space Station
to grow for two weeks in a near-gravity-free environment. The goal is
to develop three-dimensional cancer cell clusters that function more like
cancer in humans than the two-dimensional cell cultures traditionally
grown in petri dishes.

For the last nine years, USF cell biologist Jeanne Becker,
PhD, has used NASA technology to grow human ovarian cancer cells in a
chamber simulating low gravity at her Tampa General Hospital laboratory.
The breakthrough 3-D model allows her to study how the tumor cells grow
and differentiate, and, more recently, to test the effectiveness of antihormonal
therapies in combating ovarian cancer.

Now Dr. Becker will have the chance to see the effect
of the true near-zero gravity of space on the study of ovarian cancer

“I believe,” Dr. Becker said, “that space-based technology
offers an incredibly exciting and extremely unique approach to understanding
the biology of this devastating women’s disease.”

In addition to the ovarian cancer cell line provided
by Dr. Becker, experiments with kidney epithelial cells, colon cancer
cells and neuroendocrine cells, supplied by three other investigators,
will be conducted in space. This will be the first set of cell culture
studies to be performed aboard the International Space Station.

Once the ovarian cancer tissue is preserved and flown
back to earth, the experimental results will be analyzed by Dr. Becker
in her lab at Tampa General and by NASA researchers at the Johnson Space
Center in Houston. Scientists hope the new knowledge will help them define
mechanisms in tumor cell development that can be targeted for treatment
in patients with ovarian cancer ã a disease typically not detected until
reaching advanced, often incurable stages.

In 1992, Dr. Becker was one of a dozen researchers to
begin studies using a revolutionary tissue culture chamber designed at
NASA’s Johnson Space Center. The chamber, known commercially as the rotating
wall vessel (RWV) bioreactor, is used today by more than 120 scientists
across the country in NASA-sponsored projects.

The RWV was developed to grow cells with minimal influence
of the earth’s gravity so that cells could be transported into space without
being subjected to destructive forces during launch and landing. This
low gravity, or microgravity, environment produces three-dimensional tumors
that look and behave more like tumors found inside the body than the flat,
two-dimensional layers of tumor cells grown in petri dishes and flasks.

Dr. Becker uses the RWV to create three-dimensional tissue
models for ovarian and breast tumors — two cancers extremely difficult
to grow outside the human body. She not only wants to better understand
how tumors develop, but also to discover ways genes might be altered to
kill the cancers. She is also measuring tumor sensitivity to chemotherapy
and antihormonal therapy.

The response of cells to a drug can be changed dramatically
by the way those cells are grown. Tumor cells grown three dimensionally
in the RWV are more drug resistant than when grown on a flat surface.
For example, the same dose of anti-cancer agent taxol that kills ovarian
cancer cells grown in a plastic dish will not kill all the cancerous cells
in the more complex 3-D model. “The remaining cells continue to grow,
mirroring what happens in patients who fail chemotherapy,” Dr. Becker

The challenge is finding ways to overcome persistent
drug resistance — the main problem of chemotherapy. “Ultimately,” Dr.
Becker said, “I’d like to use 3-D models for ovarian and breast cancer
to more reliably test new drugs and hormone therapies before they are
administered to patients. It could give physicians a better first shot
at predicting which treatments will work.”

In space researchers can grow larger, more advanced 3-D
cell masses and actually determine whether there is a difference in cell
function between microgravity on earth and the real thing. “We eventually
need to apply what we learn from microgravity studies at the cellular
level to animals and humans,” Dr. Becker said. “This can only be accomplished
by scientists on long space missions.