Researchers from the Georgia Cancer Center at Augusta University have developed a tripartite chimera molecule to treat some types of breast cancer.
The molecule is designed to decrease the expression of human epidermal growth factor receptor 2 (HER2), human epidermal growth factor receptor 3 (HER3) and epidermal growth factor receptor (EGFR) simultaneously.
These growth factors are known to be over-expressed in certain cancers, leading to the cancer becoming more aggressive and drug resistant in 20% to 30% of breast cancers.
Georgia Cancer Center bioengineer Dr Hongyan Liu said: “When HER2 is expressed in a cell, you’ll usually find high expression of HER3, too. As a bioengineer, I am developing the materials for cancer-targeted treatment. I have experience building multifunctional chimeras to target different types of genes associated with cancer cells.”
Called HER2 aptamer-EGFR siRNA-HER3 aptamer chimera, the new molecule is comprised of an EGFR-targeting component in the middle of the HER2 and HER3-targeting components.
The design is intended to allow the EGFR component to access its target within HER2- and HER3-expressing cells. All the three parts of the molecule possess anti-tumour activity.
The new chimera interferes with HER2 and HER3 signaling and ultimately leads to cancer cell death, as shown in the group’s recent publication in Molecular Therapy: Nucleic Acids.
The comparatively large size of the molecule means it avoids renal depletion, enabling long-term circulation.
Researchers are conducting further studies to assess if the molecule can work against breast cancers that are resistant to a HER2-targeting drug called Herceptin.
They expect that the molecule can be used to treat other cancers characterised by HER over-expression such as lung, head or neck cancer.