Identification of Circulating Tumor Cells in Patients with Lung Cancer using DNA Aptamers

BACKGROUND: Lung cancer (LC) is one of the most prevalent types of cancer, with mortality rates reaching 25% of all cancer-related deaths. The majority of patients are classified as stage IV at the time of diagnosis, a stage at which the probability of successful treatment is considerably low. Conventional diagnostic methods for lung cancer are expensive, labor-intensive, and highly invasive if a biopsy is performed. Consequently, liquid biopsy, which involves the extraction of circulating tumor cells from blood samples, has emerged as a pivotal area of research in oncology. AIM: To develop a method for the isolation and identification of circulating tumor cells in the peripheral blood of patients with lung cancer using DNA aptamers. MATERIALS AND METHODS: The study objects are lung cancer tissue, blood of patients with lung cancer and primary lung cancer cell culture. Gold-decorated magnetic nanoparticles and thiolated aptamers LC-17, LC-183 and LC-224 were used to isolate proteins. A hybrid of a thiol primer and a non-specific DNA sequence composed of two AG nucleotide repeats was used as a control. Mass spectrometry was performed using UltiMate 3000 nano-UHPLC system coupled with Orbitrap Fusion mass spectrometer (Thermo Scientific, USA). Circulating tumor cell counts were measured on CytoFLEX flow cytometer (Beckman Coulter, USA) after triple staining. Fluorescence microscopy was used for CSC visualization. RESULTS: The potential protein targets of the aptamers LC-17, LC-183, and LC-224 were identified. These aptamers were then used to isolate circulating tumor cells from the blood of patients with lung cancer. The identification of circulating tumor cells was performed using flow cytometry and fluorescence microscopy. CONCLUSIONS: The proposed method for the identification of circulating tumor cells through magnetic separation and flow cytometry provides a quantitative analysis of the target analyte, facilitated by the use of cell-specific lung cancer aptamers, including LC-17, LC-183, and LC-224, which exhibit high-affinity binding properties.