Cancer is a devious enemy. In lab tests, researchers have identified plenty of exciting genetic targets — weak links that should allow them to destroy tumors by halting production of a crucial enzyme, for example, or blocking a signal the cell needs to keep growing. All too often, however, these promising findings fizzle out in further testing.
That is because cancer cells can take advantage of multiple, redundant signaling pathways to avoid areas that come under attack. “Tumor cells will just figure out a way to bypass them,” said Eddy Yang, M.D., Ph.D., an associate scientist in the UAB Comprehensive Cancer Center and associate professor in the UAB Department of Radiation Oncology.
Mapping out the complex pathways involved in cancer and other diseases is a crucial step in finding better treatments — and identifying the best treatments for individual patients. If you know all the routes a tumor can use to evade attack, you can find therapies — or combinations of therapies — to block them all. Indeed, tracing cancer-related signaling pathways, and finding ways to use these insights to improve diagnosis and treatment decisions, is a major focus of research at the Cancer Center, Yang says. But spotting these pathways amid the information overload of a genomewide screening test can be extremely complex and time-consuming.
|nCounter: In Focus |
Targeting Crucial PathwaysNow, UAB researchers and clinicians have a new tool to investigate signaling pathways — and to translate their discoveries into clinic-ready diagnostic tests. The unique nCounter Analysis System, produced by Nanostring Laboratories, “is a platform to measure the expression of genes in a targeted manner,” Yang said. “Instead of looking at the whole genome, you can investigate anywhere from 48-800 genes at a time.” Researchers can zero in on certain pathways that they are studying, Yang explains, or they can use preset panels of previously identified cancer networks.
Yang directs the new UAB Nanostring Laboratory, which is open to investigators across campus. He is using the nCounter to pursue his own research in experimental treatments for breast, prostate, and head and neck cancers. “I’m very interested in understanding the pathways that make a tumor tick,” Yang said. “I want to know which ones make it resistant to therapy and which ones could actually make it more sensitive to treatment.” With the nCounter, Yang said, “we can look from a 10,000-foot perspective rather than from sea level. It’s an exciting technology.”
Another advantage of the nCounter is that, unlike other technologies, which may require whole molecules of high-quality RNA or amplification for analysis, the nCounter can gather information from small pieces of RNA. That means researchers can use it to look at pathways in tissue that is up to several decades old, retroactively verifying new patterns they have found instead of having to collect new samples for analysis. The nCounter can also perform a range of other tests, Yang says, including analysis of microRNAs, gene fusions and gene amplifications.
From Concept to ClinicThe nCounter is more than a research tool. It can run new diagnostic tests such as the ProSigna Assay, which gives clinicians an estimate of a patient’s likelihood of tumor recurrence based on which pathways are active in that patient. It is an excellent example of personalized medicine in action, Yang says. He envisions UAB researchers using the nCounter to develop novel tests to inform treatment decisions in cancer and other diseases. UAB is one of the first institutions nationwide with the ability to do both laboratory and clinical testing using the nCounter.
|“We hope to use the pattern of the pathway of genes to help guide therapy,” Yang said. “That’s the personalized medicine approach.”|
Yang and collaborator Andres Forero, M.D., senior scientist at the UAB Cancer Center, will use the nCounter as part of a clinical trial testing a new treatment approach against triple-negative breast cancer. The trial, which recently began enrolling patients, is testing two different drugs — a PARP inhibitor and an EGFR inhibitor — to block two different pathways used by these tumors.
“By blocking PARP, you block the ability of the tumors to repair DNA damage,” which should eventually result in cell death, Yang explains. But the tumors can take advantage of an alternate backup pathway to repair that damage, meaning PARP inhibitors alone are often ineffective. “By blocking EGFR, we will block that backup pathway,” Yang said. [To learn more about this study, call (205) 934-0309; visit the Clinical Trials section of the Comprehensive Cancer Center's website to see all current studies.]
Using the nCounter, the researchers will compare the pathways altered in patients who respond to the therapy with those in patients who aren’t helped by the combination. In the future, that could let them identify the most appropriate patients for this treatment with a simple test. “We hope to use the pattern of the pathway of genes to help guide therapy,” Yang said. “That’s the personalized medicine approach.”