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Tumor Metastisis Study Now Underway

The “glow” of a GFP protein gene, implanted in nude mice, enables Stehlin researchers to track cancer growth and the effects of drug treatment.

Cancer is not a complacent disease – it is never content to stay in one spot. In fact, the defining characteristic of malignant cancer cells is their ability to break off from the body of a tumor, travel through blood or lymph systems and deposit and grow as a secondary tumor, in another part of the body. This process is called metastasis.

These diseased, migrating cells can be microscopic and difficult to detect as they
travel. The challenge has been to study patterns of metastasis, as they differ among
types of cancer and different types of tumors.

In 2005, the Stehlin Foundation embarked on a study to determine exactly how cancer spreads, or metastasizes, using its signature nude mice model.

The study utilizes Green Fluorescent Protein (GFP), which involves a gene capable of producing a fluorescent protein in the human cancer cells implanted into the mice. Under a blue light, the GFP gene causes the cells to emit a green glow.

This is the important part: Because the “green glow” characteristic is passed on from one generation of cancer cells to another, scientists can visualize growth and metastasis as it occurs by watching how the fluorescent light emitted from the mouse changes. The emitted light from both the original and secondary tumor sites can be localized and measured.

Searching for Results Today
When asked how this particular study came about, Constantine S.A. Markides, Ph.D. researcher at the Stehlin Foundation, explains that it was a decision based on the Foundation’s focus of looking for ways todirectly impact the quality of patient care.

Metastasis is a critical issue, because it is the secondary, or metastasized, tumors that are most often deadly in cancer patients. The approach of using GFP-carrying human cancer cells in the nude mice allows the Foundation to create metastasis and treatment conditions that closely parallel those of humans.

“Remember, different cancers spread in different patterns,” remarked Dr. Markides,
the Foundation’s chief pharmacologist. “Through this technology, we can, first,
establish how different cancers spread. Our immediate next step is to compare and
contrast the effectiveness of different drugs and drug combinations in treating primary
and metastatic cancer.

“Of course, the ultimate challenge is to determine whether it is possible to block the metastatic spread of a tumor.”

As of this spring the GFP cells were in culture, ready to be implanted into the mice. Dr. Markides expects that within 6-8 months the Foundation should be seeing the first results from the GFP Tumor Metastasis Study.

We’re very excited to see how our family of camptothecin drugs performsunder these conditions,” he said. “We believe their potential is extremely promising in reducing the growth and spread of human cancers.”


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