Achilefu receives inaugural breast cancer research award

Samuel Achilefu, PhD, a scientist and inventor at Washington University School of Medicine in St. Louis, has been recognized as the first recipient of the Breast Cancer Research Program Distinguished Investigator Award, from the U.S. Department of Defense.

The award comes with $4.5 million to support his innovative work to use light to activate drugs and the immune system in the body. He is developing the approach as a safer and more effective way to treat breast cancer than currently available chemotherapy drugs.

Washington University scientists led by Samuel Achilefu, PhD, have devised a way to apply light-based therapy to deep tissues never before accessible (animated above). They delivered light directly to tumor cells, in the form of an imaging agent frequently used in PET scans. This light source, along with a novel cancer-targeting product and a chemotherapy drug, selectively kill cancer cells.

So-called photoimmunotherapy also has the potential to help those with breast cancer that has spread, which typically evolves to become resistant to chemotherapy. Metastatic disease is responsible for more than 90 percent of the 41,000 breast cancer deaths in the U.S. each year.

Washington University scientists led by Samuel Achilefu, PhD, have devised a way to apply light-based therapy to deep tissues never before accessible. They delivered light directly to tumor cells, in the form of an imaging agent frequently used in positron emission tomography (PET) scans. This light source, along with a novel cancer-targeting product and a chemotherapy drug, selectively kill cancer cells.

“The goal is to harness the power of light and cancer-specific tumor targeting strategy to effectively treat tumors while minimizing or even eliminating damage to neighboring healthy cells,” said Achilefu, the Michel M. Ter-Pogossian Professor of Radiology and a research member of Siteman Cancer Center. “By developing a better way to deliver existing drugs or new ones, we hope to extend and improve the lives of patients.”

The new award was established for “exceptionally talented researchers who have shown that they are leaders in their fields through extraordinary creativity, vision, and productivity,” according to the defense department.

Light has long been used to treat cancer, but phototherapy is effective only where light easily can reach. Previously, this limited its use to cancers of the skin and in areas of the body accessible with an endoscope, such as the gastrointestinal tract.

However, Achilefu and his team used a mouse model of cancer to devise a way to apply light-based therapy, called stimulated intracellular light therapy (SILT), to deep tissues never before accessible. Instead of shining an outside light, they delivered light directly to tumor cells, in the form of an imaging agent frequently used in PET scans. This light source, along with a novel cancer-targeting product and a chemotherapy drug – one that is a photosensitive source of free radicals that can be activated by the light – selectively kill cancer cells. The researchers did so using materials already approved for use in cancer patients. Further, the therapy destroys the cancer gradually, triggering an immune response that further enhances the attack on tumor cells.

The method is aimed at treating patients with many different types of breast cancer, including triple-negative breast cancer, which often doesn’t respond to conventional therapies. Achilefu also plans to explore whether light therapy can prevent a recurrence of breast cancer if it is used as an annual treatment.

Co-investigators are Katherine Weilbaecher, MD, a professor of medicine, and Robert Schreiber, PhD, the Alumni Endowed Professor of Pathology and Immunology, both at the School of Medicine.

Achilefu also is chief of the Optical Radiology Laboratory at Mallinckrodt Institute of Radiology and director of the Center for Multiple Myeloma Nanotherapy at the School of Medicine. He is the recipient of numerous awards, including the prestigious St. Louis Award, given to residents of the St. Louis area whose achievements reflect positively on the community.