Repurposing Niflumic Acid-Loaded PEGylated Cerosomes for Topical Solid Ehrlich's Carcinoma Management via...

Background/Objectives: Repurposing existing drugs may represent a promising strategy for effective cancer therapy. This study was the first to investigate the augmented antitumor therapeutic effect achieved by co-incorporating the NSAID Niflumic acid (NIF) with ceramides into PEGylated cerosomes (NIF-loaded PEG-CERs) in a novel platform that targets specifically the MAPK-ERK signaling pathway and miR-21-5p modulation. Methods: The prepared formulae were statistically optimized utilizing a full factorial design and the optimal formula (C5) was further incorporated into a topical gel and evaluated for ex vivo rat skin permeation, and tested in vivo in a subcutaneous solid Ehrlich carcinoma (SEC) mice model. Results: The optimal formula (C5) showed tubular elongated morphology with higher EE% (96.71 ± 0.0), lower vesicular size (VS) and PDI values, 292.95 ± 0.78 nm and 0.47 ± 0.0 respectively. A high ZP value (-37.5 ± 0.57 mV) was in accordance with stability results showing good stability of the optimal formula (C5). Permeability studies exhibited 2.02-fold higher skin permeation compared to pure NIF gel. A significant decrease in tumor volume and marked improvement in survival rate in SEC mice were confirmed by downregulation of EGFR, ERK1, ERK2, and miR-21-5p expression. Furthermore, an increase in total antioxidant capacity and caspase-3 levels was observed, accompanied by significant suppression in cyclin D1, MMP-2, COX-2, and MDA levels. Finally, histopathological analysis revealed the superior antitumor effect of C5 gel together with immunohistochemical assay showing the lowest BCL-2-positive staining, indicating the restoration of physiological apoptotic balance. Conclusions: Based on the previous findings, NIF-loaded PEG-CERs offer augmented therapeutic potential for efficient topical skin cancer management in an SEC mice model.