Scientists at the Cancer Therapy & Research Center (CTRC) have announced that they are looking at the role of proteins – with some promising results. A recent CTRC study demonstrated the potential of focusing on an individual's protein composition, and levels of certain proteins associated with particular cancers, to both predict cancer susceptibility and help determine the effective therapy for that individual.
The study shows a correlation between levels of certain proteins in human tumor cells and the effectiveness of two of the common chemotherapy drugs for lung, prostate and breast cancer.
Results of the study are published in the July-August issue of Cancer Genomics & Proteomics. Researchers tested docetaxel (Taxotere®) and paclitaxel (Taxol®), common cancer drugs that inhibit cell growth by stopping cell division. Docetaxel was found to be superior to paclitaxel in inhibiting growth of human lung and prostate cancer cells that had low levels of Bcl-2, an 'anti-death' protein that protects cancer cells and allows them to multiply.
Yet docetaxel was no more effective than paclitaxel against breast cancers, which showed high levels of Bcl-2. Current observation on notable impact of docetaxel in tumors with little Bcl-2 warrants further study of biomarkers for drug sensitivity as well as investigation of docetaxel in combination with drugs that reduce Bcl-2 levels, according to Izbicka.
The researchers also used a sensitive method for protein profiling to identify a potential biomarker for docetaxel response. "These early findings provide a proof of concept that through proteomic profiling we may be able to identify biomarkers that exist in certain cancer types and not others," explained Dr. Elzbieta Izbicka, of the CTRC's Institute for Drug Development. He adds, "By better understanding drug effects in cell culture and animal models of human cancers, there is incredible potential to find new opportunities for targeted drug development as well as detection and treatment of cancer based on protein profiling."
Further he said, "An individual's Bcl-2 level might turn out to be an important determinant of docetaxel sensitivity and therefore help determine the most effective course of therapy for that particular patient. Other biomarkers may be equally important." Proteomics is expected to be increasingly used in cancer diagnosis and treatment, which involves searching for proteins that may serve as biomarkers of early disease, of responsiveness to therapy, or of the likelihood of relapse after treatment, Izbicka said.