Overcoming chemo resistance
Once diagnosed with the disease, many ovarian cancer patients receive platinum chemotherapy. Unfortunately, it doesn't work for all of them, which means some women suffer needlessly — with no disease-busting benefit.
Last year, Hutch clinical researcher Dr. Amanda Paulovich was tapped by the NCI to participate in a new project using targeted proteomics and genomics (i.e., “proteogenomics”) to help differentiate those who will respond from those who won’t — before any chemo is given.
“Fifteen to 20 percent of patients have tumors that never respond to this chemo,” said Paulovich, who is leading one of three multisite collaborations created by the NCI’s Proteogenomic Translational Research Centers initiative. “Their disease continues to progress. But by the time we figure this out, the patient is so sick they’re not eligible for a clinical trial. If you could predict this lack of response, you wouldn’t waste their time on chemo that doesn’t work. You’d get them into a clinical trial and find out how to treat those tumors.”
Proteogenomics — which integrates the study of the body’s proteins with genomic sequencing — is a promising new approach for identifying chemo-resistant patients ahead of time. This new type of sequencing may also help identify new biological targets that can be used in patients whose tumors become resistant to chemo over time, Paulovich said.
“The cancer genome on its own doesn’t encode all of the biological information on the tumor’s behavior,” she said. “Those genes are blueprints for making proteins, and proteins are what really effect how the cancer cells behave. You have to study not just DNA but the proteins.”
Her team’s analysis will bring together improved preclinical models — both human cell lines and patient-derived xenografts (i.e., mice implanted with human tumor cells) treated with platinum chemo — with genomic and proteomic analyses. Their hope is that looking at the entire network of proteins and genes provides more answers to the riddle of chemotherapy resistance.
“We have better preclinical models than we used to have, and we also have better technologies for looking at the cancer cells — in terms of the genome and the proteome,” she said. “The hope is to bring the novel tools into play and see if we can have better luck than folks have had in the past.”
Paulovich's team, which includes co-principal investigator Dr. Michael Birrer, a leading ovarian cancer researcher who heads the University of Alabama Comprehensive Cancer Center, has completed data collection on the preclinical models and is now starting its analysis. They’re also ramping up to do comparable studies in biopsies of human ovarian cancer.
“That’s the next wave,” she said. “Then we’ll combine the preclinical [mouse and cell line] information and [human] tumor analysis and see if we can identify any pathways and predictors. And then we’ll go on to validate anything that we find.”