Pulmonary delivery of siRNA targeting EGFR and PD-L1 in in vivo traceable NSCLC models
Rico Chi Hang Man1,2, Susan Wai Sum Leung1, Jenny Ka Wing Lam1,3 & Gilbert O. Fruhwirth2
1 Laboratory of Macromolecular Drug Delivery, Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong SAR
2 Imaging Therapies and Cancer Group, Comprehensive Cancer Centre, School of Cancer and Pharmaceutical Sciences, Teaching Department of Biochemistry, Faculty of Life Sciences and Medicine, King’s College London, London, United Kingdom
3 Department of Pharmaceutics, UCL School of Pharmacy, University College London, London, United Kingdom
Summary
Non-small cell lung cancer (NSCLC) is the leading cause of cancer mortality globally. NSCLC is frequently associated with an up-regulation of epidermal growth factor receptor (EGFR) and programmed death-ligand 1 (PD-L1), where the former promotes tumour survival and the latter prevents cancer cells from immune detection. However, existing therapeutics, such as EGFR and PD-1/PD-L1 inhibitors or monoclonal antibodies are subject to drug resistance, poor response rate and tumour relapse, thereby limiting their efficacies. The development of an alternative therapeutic strategy for NSCLC is of the utmost urgency. Recently, small interfering RNA (siRNA) emerges as a novel anticancer therapeutic. It inhibits specific gene expression of proteins involved in tumorigenesis through RNA interference (RNAi). We aim to inhibit both EGFR and PD-L1 expressions using siRNAs to enhance NSCLC treatment outcome. To track the tumour progression following siRNA treatments, we successfully engineered and characterised two in vivo traceable NSCLC cell models, which express either luciferase (for 2D bioluminescence imaging) or NIS-TagRFP (for 3D radionuclide tomography). Furthermore, the expressions of EGFR and PD-L1 were significantly reduced in human lung cancer cells mediated by synthetic PEG12-KL4 peptide, which acts as an efficient siRNA delivery vector. More importantly, initial in vivo work demonstrated that the delivery of siRNA through intratracheal route was safe and effective in maximising siRNA concentration in the lungs. With the successfully validated in vivo traceable NSCLC lines, orthotopic NSCLC models will now serve to evaluate anti-tumour effects of siRNA treatment on EGFR and PD-L1 knockdown.
Key Message
This study successfully established and validated two in vivo traceable NSCLC cell lines. The expressions of EGFR and PD-L1 were significantly reduced in these NSCLC cells mediated by PEG12-KL4 peptide. Initial in vivo work also demonstrated that pulmonary administration was effective in attaining siRNA localisation in the lungs.