Abstract P91: Development of CEACAM6-Targeted Single-Domain Antibody-Functionalized Liposomal Doxorubicin for Targeted Therapy of Lung Cancer Brain Metastases

Abstract

Brain metastases in non-small cell lung cancer (NSCLC) pose a critical treatment hurdle due to the blood–brain barrier’s (BBB) restriction on drug delivery. While liposomal doxorubicin improves circulation and reduces toxicity, it lacks active targeting ability to reach the brain and bypass the BBB. We aim to overcome these limitations by developing single-domain antibodies (sdAbs) against carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6), a biomarker overexpressed in NSCLC brain metastases, and conjugating them to PEGylated liposomal doxorubicin. Liposomes were synthesized via solvent injection and subsequently extruded to achieve uniform particle size. Ammonium sulfate served as the aqueous phase to facilitate remote loading of doxorubicin. The CEACAM6-targeting 2A2 sdAb was expressed in E. coli, purified via affinity chromatography, and validated for specificity through ELISA and cytotoxicity assays. The 2A2 sdAb was conjugated to DSPE-PEG-Mal and the resulting micelles were post-inserted into preformed liposomal doxorubicin. Liposomal formulations were characterized for particle size, polydispersity index (PdI), zeta potential, and encapsulation efficiency. Preliminary data confirm high CEACAM6 expression in lung adenocarcinoma lines, successful purification of 2A2 sdAb, selective CEACAM6-dependent cytotoxicity mediated by 2A2 sdAb. Nanoparticle characterization confirms effective conjugation and formulation stability (100–120 nm; PdI 0.04–0.10; ζ –40 to –12 mV). These findings support the feasibility of CEACAM6-targeted liposomal doxorubicin as a promising strategy for NSCLC brain metastases. Ongoing studies will assess cellular uptake, targeting specificity, and biodistribution in vitro and in vivo.