A novel anti-PD-L1 DNA aptamer, Apta35 enhances non-small cell lung cancer cell cytotoxicity and apoptosis through lung cancer-activated T lymphocytes

The prevalence of Programmed death ligand 1 (PD-L1) expression in the population of NSCLC patients and blocking the PD1/PD-L1 pathway by inhibiting the PD-1 receptor on immune cells or the PD-L1 ligand on tumour and/or immune cells can inhibit tumour growth. EFBALite algorithm that enables efficient and cost-effective selection of aptamers, expediting the process. Here, we present the development, computational validation, and in vitro analysis of NSCLC of DNA aptamers targeting PD-L1. The Gibbs free energy of two anti-PD-L1 aptamers, Apta35 and Apta90 with −3.06 and − 2.4 kcal/mol respectively. The docking score for Apta35 was −272.3 and 1171.765 for HDOCK and ZDOCK respectively. Further, the Apta35 was taken for the in vitro studies as it was more stable and incubated with NCI-H460. Initially, we confirmed the binding of the TAMRA-labelled Apta35 to the NCI-H460 cell surface through microscopic imaging and further confirmed through FACS analysis. Further experimental results showed that the Apta35 treated along with the act-T cells group reduced the percentage of viability (28 ± 3.5), increased toxicity, and reduced count of NCI-H460 cells when compared with the cells treated only with the act-T cells concerning the treatment to 50 nM concentration. In summary, targeting PD-L1 with a specific aptamer provides an innovative strategy for targeting NSCLC. Apta35 aptamer showed no significant toxicity in the BALB/c nude mice while it was injected every 2 days for a total of 12 days of treatment.