Evaluation of aptamers for targeted radiotherapy: Binding specificity and labelling with natural lutetium

Many cancer patients suffer from serious side effects when treated with external beam radiotherapy or chemotherapy because of damage to healthy tissues by lack of selectivity. In this regard, specific targeting of tumours through radiopharmaceuticals is increasingly considered as a promising strategy in oncology. Radiopharmaceuticals consist of a radionuclide coupled to a vector that specifically targets cancer-related molecules.
Aptamers are small (5-15 kDa) synthetic oligonucleotides (DNA or RNA) that possess several advantages compared to other vectors, such as an relatively easy and cheap chemical synthesis allowing the introduction of different chemical modifications, a selection possible against almost every target, a non-immunogenicity and a good tumour penetration. That is why aptamers are regarded as promising molecules for the development of radiopharmaceuticals.
An aptamer targeting the Human Epidermal growth factor Receptor 3 (HER3), which plays an important role in cancer development and progression, was chosen for the development of aptamer-based radiopharmaceuticals.