Targeting lung cancer with clinically relevant EGFR mutations using anti-EGFR RNA aptamer

A significant fraction of non-small cell lung cancer (NSCLC) cases are due to oncogenic mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR). Anti-EGFR antibodies have shown limited clinical benefit for NSCLC, whereas tyrosine kinase inhibitors (TKIs) are effective, but resistance ultimately occurs. The current landscape suggests that alternative ligands that target wild-type and mutant EGFRs are desirable for targeted therapy or drug delivery development. Here we evaluate NSCLC targeting using an anti-EGFR aptamer (MinE07). We demonstrate that interaction sites of MinE07 overlap with clinically relevant antibodies targeting extracellular domain III and that MinE07 retains binding to EGFR harboring the most common oncogenic and resistance mutations. When MinE07 was linked to an anti-c-Met aptamer, the EGFR/c-Met bispecific aptamer (bsApt) showed superior labeling of NSCLC cells in vitro relative to monospecific aptamers. However, dual targeting in vivo did not improve the recognition of NSCLC xenografts compared to MinE07. Interestingly, biodistribution of Cy7-labeled bsApt differed significantly from Alexa Fluor 750-labeled bsApt. Overall, our findings demonstrate that aptamer formulations containing MinE07 can target ectopic lung cancer without additional stabilization or PEGylation and highlights the potential of MinE07 as a targeting reagent for the recognition of NSCLC harboring clinically relevant EGFRs.

Development of Liposomal Vesicles for Osimertinib Delivery to EGFR Mutation-Positive Lung Cancer Cells

Osimertinib (OSI, AZD9291), is a third-generation, irreversible tyrosine kinase inhibitor (TKI) of the epidermal growth factor receptor (EGFR) that selectively inhibits both EGFR-TKI–sensitizing and EGFR T790M resistance mutations. OSI has been approved as a first-line treatment of EGFR-mutant lung cancer and for metastatic EGFR T790M-mutant non-small cell lung cancer. Liposome-based delivery of OSI can provide a new formulation of the drug that can be administered via alternative delivery routes (intravenous, inhalation). In this manuscript, we report for the first time development and characterization of liposomal OSI formulations with diameters of ca. 115 nm. Vesicles were composed of phosphatidylcholines with various saturation and carbon chain lengths, cholesterol and pegylated phosphoethanolamine. Liposomes were loaded with OSI passively, resulting in a drug being dissolved in the phospholipid matrix or actively via remote-loading leading to the formation of OSI precipitate in the liposomal core. Remotely loaded liposomes were characterized by nearly 100% entrapment efficacy and represent a depot of OSI. Passively-loaded vesicles released OSI following the Peppas-Sahlin model, in a mechanism combining drug diffusion and liposome relaxation. OSI-loaded liposomes composed of l-α-phosphatidylcholine (egg-PC) demonstrated a higher toxicity in non-small lung cancer cells with EGFR T790M resistance mutation (H-1975) when compared with free OSI. Developed OSI formulations did not show antiproliferative activity in vitro in healthy lung epithelial cells (MRC-5) without the EGFR mutation.