By studying light-sensitive particles that latch onto cancer cells, a biomedical engineering researcher at The University of Texas at Austin and a medical physics expert at The University of Texas M. D. Anderson Cancer Center are developing a technique to clarify within one office visit whether someone’s cancer has spread from an original tumor.
The spread (metastasis) of tumor cells causes most cancer deaths. When cancer has metastasized, physicians often combine treatment of the original tumor with chemotherapy or other treatments to improve survival. But these whole-body treatments tax a person’s health, requiring tests to assure patients will benefit from added treatment.
Cancer cells usually spread first to structures near a tumor called lymph nodes. A commonly used test for cancer metastasis that can take two weeks to provide results involves injecting a blue dye and radioactive material into a cancer site to identify the first lymph node near a tumor, which may harbor metastatic cells. Removing this sentinel lymph node surgically determines the presence of cancer cells, but is invasive and carries risks. The long test timeframe also leaves families in temporary limbo about a loved one’s chance of surviving and the treatment road ahead.
Assistant professors Stanislav Emelianov and Konstantin Sokolov have received $1.3 million from the National Institutes of Health to develop technology involving a laser and ultrasound that would rapidly locate spreading cancer cells using injected nanoparticles. The approach could eventually eliminate the need for surgical lymph node removal, while providing quick cancer diagnoses. The researchers will engineer the gold-based nanoparticles to clump together on a specific molecule on cancer cell surfaces. The clumping causes the particles to absorb the red part of the color spectrum instead of absorbing the green part that isolated nanoparticles do when exposed to light.
“Using ultrasound imaging of the optical properties of tissue, we will be able to use the color change to turn these gold nanoparticles into molecularly specific nanosensors that highlight the precise location of cancer cells at depth,” Emelianov said.
Most cancer could be identified with this approach. Emelianov, Sokolov, and Dr. Ann Gillenwater, a head and neck surgeon at the Houston-based M.D. Anderson Cancer Center, will begin by spending four years testing the technology on head and neck cancers. They will test the technology in 3-dimensional, bioengineered tissue phantoms and human cancer cells grown in laboratory flasks, in small animals, and in a few cancer samples taken from human patients.
The nanoparticles they will study have an antibody attached to them that latches onto a protein found on the surface of all head and neck cancers. The researchers will see how well the nanoparticles attach to cancer cells that make it to the sentinel lymph node, part of a system of vessels and marble-sized structures (nodes) that collect fluid draining from tissues throughout the body.
Cancer cells use this lymph system as their highway to spread to new organs, so the presence and amount of cancer cells in the sentinel lymph node downstream from a tumor provide feedback on a cancer’s severity.
Note: Emelianov and Sokolov are Austin-based faculty in the interinstitutional Biomedical Engineering Department involving The University of Texas at Austin, The University of Texas M. D. Anderson Cancer Center, and The University of Texas Health Science Center in Houston.
