This gene transfer vector helps locate and destroy malignant breast cancer cells that have spread to the bone marrow by delivering tumor-suppressing genes or cytotoxic drugs to wherever they are needed in the patient’s body. In about 25 percent of breast cancers, a protein called HER2/neu is found at 100 times normal levels. This protein encourages cell growth, causing HER2/neu-overexpressing cancers to be particularly aggressive. The only drug that targets HER2/neu-positive cancer is Herceptin®, which is ineffective against metastasis into the bone marrow. Approximately 30 percent of breast cancer patients eventually develop bone marrow metastasis, and no targeted treatment exists for these individuals. Researchers at the University of Florida have engineered parvovirus B19 into a form that easily targets HER2/neu-positive cancer cells and can deliver various types of therapy, including drugs and beneficial genes. The $8.6-billion-dollar breast cancer market is expected to reach $10.9 billion by 2018. Herceptin® (trastuzumab), the best-selling breast cancer drug, generates $3.4 billion in annual revenue alone, indicating the market for this gene transfer vector is sizable.
A gene transfer vector for treating HER2/neu-overexpressing cancer metastases that have spread to the bone marrow
Gene vectors are vehicles, often viruses, that can transport genetic material into living organisms when one or more of their original genes are faulty or missing. University of Florida researchers have inserted certain sequences into the gene coding of parvovirus B19’s capsid to develop a gene transfer vector that specifically targets HER2/neu-positive cells. The modified virus can bind to cells high in HER2/neu. In this way, the treatment is localized to only those cells high in HER2/neu, limiting damage to healthy tissue. The vector can transport therapeutic agents and proteins, reporter proteins used to detect presence of cancer cells, tumor-suppressor genes, suicide genes and cytotoxic drugs.
