Researchers and clinicians develop effective treatments

Waging the War Against Cancer

M/Sylvester Comprehensive Cancer Center is in the midst of an aggressive expansion of laboratory and clinical research. Paired with other scientists at the School of Medicine, these researchers and clinicians are employing new weapons in the fight against cancer. Three such novel trials and treatments—available only in South Florida—are helping patients battle the disease.

Feed a Cold, Starve a Tumor

s tumors grow in the body, they mostly feed off of a parasitic blood supply for life-giving energy. But some cancer cells, like those in tumors without a normal blood supply or those in the center of a large tumor, can’t get enough oxygenated blood. As a consequence, this population of tumor cells grows more slowly. Since standard chemotherapy attacks cells that divide quickly, the slow-growing tumor cells survive.

Theodore J. Lampidis, Ph.D., suspected that there might be a way to target the slow-growing cells in a tumor through glycolysis—the process by which cells process sugar to maintain viability.

Lampidis, a professor of cell biology and anatomy, reasoned that since slow-growing tumor cells are in a microenvironment of low oxygen (hypoxia), they metabolize sugar less efficiently and need much more sugar to survive. Since the hypoxic tumor cells aggressively take in more sugar, if they are fed false sugars, their only energy source is cut off and they die.

“Feed a cold, starve a tumor,” says Lampidis.

Lampidis uses an analog of glucose, a false sugar—2-deoxyglucose (2-DG)—that has shown great promise against a variety of tumors in experimental models. It is now open as a phase I clinical trial, enrolling patients with certain non-small-cell lung cancers, head and neck tumors, and colorectal cancers.

The hope is this treatment could complement chemotherapy to wipe out the whole tumor by targeting the slow-growing hypoxic cells, instead of leaving them alive, undetected, and able to give rise to new fast-growing cells.

The Future is Bright

ecause of the sensitivity of some tumor locations, such as those inside the throat and in fragile lung tissue, surgeons may be reluctant to do procedures unless there is no choice. Patients at UM/Sylvester now have one more alternative— photodynamic therapy (PDT).

This noninvasive treatment uses light to treat shallow tumors in sensitive areas of the body that are difficult to reach with conventional surgery. “Cancer often starts on the surface before it grows deep in the mouth or throat,” says Francisco Civantos, M.D., F.A.C.S., a head and neck surgeon at UM/Sylvester.

The PDT system uses a non-thermal laser. Two days before treatment, the patient takes the medication Photofrin, which makes the body extremely light-sensitive. “The advantage of photodynamic therapy is that you shine the laser at the tumor and it can kill malignant cells in one shot,” Civantos explains.

There are some drawbacks. For example, patients must go to great lengths to avoid sunlight for up to six weeks, and there is discomfort after the procedure, which can inhibit the ability to swallow during recovery.

Smart Bomb in the War on Cancer

he body’s immune system is a weapon against disease, but it can’t always stand up to invaders like cancer. Painting a target with antibodies can help.

“There are natural killer cells that can recognize and destroy tumor cells that have been covered or labeled with an antibody that earmarks those cells for destruction,” says Joseph Rosenblatt, M.D., scientific director at UM/Sylvester.

Eckhard Podack, M.D., Ph.D., chair of the Department of Microbiology and Immunology, is studying a molecule, CD30, which is found on the surface of lymphoma cells but is rarely found on the surface of normal cells.

Podack derived a monoclonal antibody, C10, specifically selected to target CD30. The antibody was modified for human use into a biological, SGN-30. He is studying whether SGN-30 will tell the malignant cell to “switch off,” or kill itself, or attract natural killer cells to destroy tumor cells. Because the therapy is targeted, it should have fewer side effects than chemotherapy.

SGN-30 is now in a phase II clinical trial at UM/Sylvester, open to patients with Hodgkin’s disease and certain non-Hodgkin’s lymphomas and leukemia.

Illustration by Ron Chan
University of Miami Medicine Online
tool bar