Delivery represents a major hurdle to the clinical advancement of oligonucleotide therapeutics for the treatment of disorders such as Duchenne muscular dystrophy (DMD). In this preliminary study, we explored the ability of 2′-O-methyl-phosphorothioate antisense oligonucleotides (ASOs) conjugated with lipophilic ursodeoxycholic acid (UDCA) to permeate across intestinal barriers in vitro by a co-culture system of non-contacting IEC-6 cells and DMD myotubes, either alone or encapsulated in exosomes. UDCA was used to enhance the lipophilicity and membrane permeability of ASOs, potentially improving oral bioavailability. Exosomes were employed due to their biocompatibility and ability to deliver therapeutic cargo across biological barriers. Exon skipping was evaluated in the DMD myotubes to reveal the targeting efficiency. Exosomes extracted from milk and wild-type myotubes loaded with 5′-UDC-3′Cy3-ASO and seeded directly on DMD myotubes appear able to fuse to myotubes and induce exon skipping, up to ~20%. Permeation studies using the co-culture system were performed with 5′-UDC-3′Cy3-ASO 51 alone or loaded in milk-derived exosomes. In this setting, only gymnotic delivery induced significant levels of exon skipping (almost 30%) implying a possible role of the intestinal cells in enhancing delivery of ASOs. These results warrant further investigations to elucidate the delivery of ASOs by gymnosis or exosomes.

Dihydroartemisinin (DHA), a first-line treatment for uncomplicated malaria, has demonstrated antitumor activity against a variety of human cancers, emphasizing its potential for repurposing as an anticancer agent. However, its short half-life and poor bioavailability hinder its application in cancer therapy. We previously demonstrated that the molecular hybridization of DHA with bile acids (BAs) enhances its anticancer activity by improving stability and reducing toxicity. Based on this rationale, here, we designed and synthesized a library of DHA-based hybrids through conjugation with ursodeoxycholic and chenodeoxycholic bile acids. Different conjugation sites and both cleavable and non-cleavable linkages were explored to enable a comprehensive structure–activity relationship analysis. The resulting BA-DHA hybrids were evaluated in vitro for their anticancer activity against HCT116 and RKO colorectal cancer cell lines. As a result of the synergistic effect of the linker type and conjugation site, the BA-DHA hybrids synthesized via click chemistry emerged as the most active compounds in both cell lines, displaying 2- to 20-fold higher activity than the parent DHA. Mechanistic investigations further revealed that the click-derived BA-DHA hybrids possess enhanced anticancer activity and antimetastatic potential, achieving comparable or even superior efficacy to the parent compound at markedly lower concentrations.