Targeted Immunoliposomal Delivery of a 5-Fluorouracil Analog in EGFR-Expressing Pancreatic Cancer Models

Introduction Dysregulated epidermal growth factor receptor (EGFR) signaling is a key mechanism driving cancer progression and metastasis. Owing to its frequent overexpression in pancreatic cancer (PCa), EGFR has become a desirable molecular target for targeted therapies. XYZ-I-73 (N-(5-fluoro-2-oxo-1-(tetrahydrofuran-2-yl)-1,2-dihydropyrimidin-4-yl) dodecanamide), a structural analog of 5-fluorouracil (5-FU), has been previously synthesized and shown to exhibit cytotoxicity against PCa cells. Methods XYZ-I-73 was entrapped in liposomes via thin-film hydration and subsequently conjugated to EGFR antibodies to produce an immunoliposome formulation- Ab-XYZ-I-73LnP (where ‘Ab’ denotes antibody-conjugated and ‘LnP’ denotes liposomal nanoparticle). In vitro efficacy was assessed by measuring cell viability and apoptosis in MiaPaCa-2 and PANC-1 cells, while pharmacokinetics and antitumor efficacy were determined in a cell line-derived xenograft (CDX) mouse model. Results Ab-XYZ-I-73LnP exhibited a mean particle size of 143nm ± 2.3, PDI (0.37), and zeta potential -46.2 ± 1.3mV. In MiaPaCa-2 cells, Ab-XYZ-I-73LnP showed remarkably higher cytotoxicity than 5-FU in both 2D (IC 50 = 2.5 ± 0.9μM vs 13.2 ± 1.1μM) and 3D cultures (IC 50 = 8.1 ± 1.1μM vs 26.7 ± 1.1 μM). Similarly, in PANC-1 cells, Ab-XYZ-I-73LnP showed lower IC 50 values compared to 5-FU;2D (IC 50 = 2.9 ±1.1 μM vs 20.4±1.2 μM), 3D (IC 50 = 12.9 ± 0.6μΜ vs 37.1±0.9 μM). Pharmacokinetic analysis revealed a prolonged half-life for Ab-XYZ-I-73LnP compared with free 5-FU (t1/2 = 1.62 ± 0.03 h vs 0.49 ± 0.01 h, p < 0.001). There was about a 2-fold increase in the area under the curve (AUC) for Ab-XYZ-I-73LnP compared to 5-FU (AUC= 0.32 ± 0.04µg/(L*hr) vs 0.15 ± 0.02µg/(L*hr), p<0.01). Conclusion Overall, the study supports the formulation of an immunoliposome of modified 5-FU, which may significantly enhance drug bioavailability and therapeutic potential for the treatment of PCa.