These aptamers, conjugated with N-heterocyclic carbene metal complexes, deliver therapeutic doses of the cytotoxic metal ion to targeted cancer cells. These complexes avoid toxicity to healthy cells while being highly effective for destruction of cancer cells. Malignant tissue growth accounted for approximately 7.5 million deaths worldwide in 2008, and that number is projected to increase to 13.2 million by 2030. Patient responses to specific drugs vary widely, calling for a more individualized treatment process. One potential approach to individualized treatment is to exploit cancer-specific biomarkers to deliver chemotherapeutic agents to the cancer cell. Available metal-based drugs are non-discriminatory, causing detrimental effects due to heavy metal buildup in the kidneys and liver, but University of Florida researchers have developed an NHC aptamer that specifically targets cancer cells and prevents dispersal of the metal ion to healthy cells in the body.
NHC metal complexes for cancer therapeutics and targeted drug delivery
Aptamers are formed by a relatively easy and reproducible DNA synthesis. Their molecular specificities are easily modified, they have low toxicity, and they are easily stored. Metal ions are highly toxic to cancer cells and combining them with aptamers provides an effective method of cancer treatment. Current metal-based drugs have detrimental side-effects due to heavy metal buildup in the kidneys and liver, but N-heterocyclic carbene aptamers are highly selective, targeting delivery only to specific cancer cells, thus requiring low dosages and reducing side effects. The aptamers target the cell surface of cancer cells and are internalized carrying the NHC metal ion that disrupts cell activity. The strong M-C bond of the NHC prevents the loss of the metal ion in the body prior to cell recognition.
