Pancreatic cancer strikes less than 2% of the population, yet this brutal disease has one of the highest mortality rates among patients, witha mean survival time of only four to six months after diagnosis. Scientists hope that earlydetection will be the key to increasing patient survival rates, and Dr.Kimberly Kelly from the University of Virginia has dedicated her research tolearning more this deadly cancer. Within the year her team hopes to go toclinical trials with new biomarkers to target early indicators of the cancer,as well as stem cells left over after removal.
Kelly’s strategy begins with bacteriophages: viruses that bind to bacteria and cause them to create millions of copies of thevirus phage. In a technique developed some years ago, scientists attach arandom amino acid sequence to the bacteriophage which causes the host bacteriato also generate millions of random peptides. Kelly and her team take this zooof peptides and throw them up against pancreatic cancerous cells and see whatsticks. Peptides that “stick” to the cancer cells are chemically bound toproteins on the cell surface and become new biomarkers for those cells. This technique can be used for any cancer ordisease and requires very few lab resources, as the peptides can all competefor the cancer cells at the same time so they don’t need individual handling orindividual tissue samples. It’s also very fast. The trade off, says Kelly, isthat it may not find all of the cell surface proteins, but it will find the highexpressers. They’ve identified about thirty where there could be tens ofthousands on the cell surface.
After finding a group of desired peptides and producing themsynthetically, the team worked to attach marker molecules to the peptides. Thus,they can inject the patient with the peptide, which will bond to the cancercells, and the marker will appear in a scan of the patient. An iron oxidemolecule will appear in an MR scan, and an indium molecule will appear in aSPECT scan. The team is looking for cancer cells as well as cancer stem cellsand pre-cancer lesions. The lesions may help in early detection, while stemcells left behind after tumor removal are often what cause recurrence. Thistargeting of specific cells could provide information about what type oftreatment doctors should pursue in individual patients or eventually assist intargeted drug delivery.
Their progress is approaching a critical phase as they hopeto have the first human trials ready within a year. They are in the process ofcompleting preclinical trials and toxicology tests. The first steps will besmall; simply making sure the biomarkers work in humans, and then identifying pre-cancer lesions. Ultimately, she says, early detection and treatmentis the goal.