Development and Characterization of PEGylated β-Carotene-Loaded Liposomes as Radiosensitizers in HepG2 Hepatocellular Carcinoma Cells: In Vitro and In Silico Studies

INTRODUCTION: Hepatocellular Carcinoma (HCC) is a leading cause of cancer death with limited responsiveness to radiotherapy. β-Carotene has chemopreventive properties, but its clinical use is hindered by poor aqueous solubility and instability. This study developed PEGylated β-carotene-loaded liposomes (PEGLipo- β-Car) as a novel nanocarrier-based radiosensitizer and used in silico modeling to explore its molecular interactions. METHODS: PEG-Lipo-β-Car was prepared via thin-film hydration and characterized (TEM, DLS, FTIR, DSC). Cytotoxicity and radiosensitization were evaluated in HepG2 cells under γ-irradiation (0, 5, 10 Gy) using MTT assays, with synergy quantified via Combination Indices (CI). Molecular docking assessed β-carotene binding to PARP and ATM. RESULTS: PEG-Lipo-β-Car exhibited good colloidal stability (size: 143.4 ± 8.2 nm, PDI: 0.201, EE >94%). At 10 Gy irradiation, it reduced the IC50 from 29.78 to 0.57 μg/mL, a 52-fold enhancement with strong synergy (CI=0.019). Empty liposomes alone conferred significant radiosensitization (~30-fold). Docking revealed β- carotene binds the catalytic sites of PARP (-9.19 ± 0.37 kcal/mol) and ATM (-10.12 ± 0.36 kcal/mol). DISCUSSION: The observed radiobiological synergy may stem from a combined effect of carrier-mediated membrane perturbation and/or ROS amplification, coupled with the potential inhibition of DNA repair pathways by the delivered β-carotene. CONCLUSIONS: PEGylation enhances β-carotene's stability and radiosensitizing efficacy in HCC cells through a combined mechanism involving carrier effects and potential interference with PARP- and ATM-mediated DNA repair. PEG-Lipo-β-Car is a promising candidate for future preclinical evaluation in hepatocellular carcinoma radiotherapy.