Folate Receptor-Targeted Liposomes Loaded with Actinomycin X2 Enhance Antitumor Potency for HCCLM3 Hepatocellular Carcinoma Both In Vitro and In Vivo

Actinomycin X2 (Act.X2), an analog of actinomycin D produced by marine-derived actinomycete <i>Streptomyces sp.</i>, has shown promising antitumor activity. This study attempted to improve the delivery efficiency of Act.X2 through a targeted approach. We developed a folate (FA)-modified, Act.X2-loaded liposomal system (FA-Act.X2-Lips) to enhance its targeting specificity and antitumor efficacy against hepatocellular carcinoma (HCC). FA-Act.X2-Lips exhibited a uniform spherical morphology, an average particle size of approximately 139.85 nm, and an encapsulation efficiency of around 88.34%. Cytotoxicity assays demonstrated that FA-Act.X2-Lips have significantly higher cytotoxicity against HCCLM3 cells compared with the unmodified Act.X2-Lips. Additionally, an orthotopic HCC model in mice was established, and tail vein injections of FA-Act.X2-Lips were administered to study targeted drug delivery. Both in vitro targeting studies and in vivo fluorescent imaging assays demonstrated that FA-modified liposomes enhanced tumor-targeting efficiency. In terms of antitumor activity, FA-Act.X2-Lips significantly inhibited tumor growth in HCCLM3 tumor-bearing mice, compared with the free Act.X2 and unmodified Act.X2-Lips, while effectively inducing tumor cell apoptosis without notable toxicity to healthy tissues. The low toxicity profile of FA-Act.X2-Lips addresses a critical clinical limitation of conventional actinomycin-based therapies. These results suggest that FA-Act.X2-Lips hold a therapeutic potential for HCC treatment.