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Betulinic acid (3β-Hydroxy-20(29)-lupaene-28-oic acid, BA) has excellent anti-cancer activity but poor solubility and low bioavailability. To improve the antitumor activity of BA, a polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol (PVCL–PVA–PEG) graft copolymer (Soluplus) encapsulated BA micelle (Soluplus-BA) was fabricated. The Soluplus-BA micelles presented a mean size of 54.77 ± 1.26 nm and a polydispersity index (PDI) of 0.083. The MTT assay results showed that Soluplus-BA micelles increased the inhibitory effect of BA on MDA-MB-231 cells, mainly due to the enhanced accumulation of reactive oxygen species (ROS) and the destruction of mitochondrial membrane potential (MMP). Soluplus-BA micelles induced the DNA double-strand breaks (DSBs) as the γH2AX foci increased. Moreover, Soluplus-BA also inhibited the tube formation and migration of human umbilical vein endothelial cells (HUVECs), and inhibited the neovascularization of the chicken chorioallantoic membrane (CAM). This angiogenesis inhibitory effect may be accomplished by regulating the HIF-1/VEGF-FAK signaling pathway. The in vivo study confirmed the improved anti-tumor effect of Soluplus-BA and its inhibitory effect on angiogenesis, demonstrating the possibility of Soluplus-BA as an effective anti-breast cancer drug delivery system.

Antibacterial hydrogels are intensively studied as wound dressings. Silk fibroin (SF) is chemical crosslinked to glycyrrhizic acid (GA) and silver to fabricate a hydrogel dressing with both antibacterial and anti-inflammatory properties. The SF/Ag/GA hydrogel exhibits high water content with acceptable mechanical properties, combines the good biocompatibility and biodegradability of SF, the antibacterial activity of silver, and the anti-inflammatory property of GA, capable to promote tissue regeneration during wound healing process, offering great potential as an alternative for wound dressings.

Acute kidney injury (AKI) is the most common side effect of the anti-cancer drug cisplatin, and currently, no effective preventive measures are available in clinical practice. Oxidative stress and DNA damage mechanisms may be involved in cisplatin-induced AKI. In this study, we prepared Kolliphor HS15-based myricetin-loaded (HS15-Myr) nanomicelles and explored the mechanism of protection against cisplatininduced AKI. In vitro results showed that the HS15-Myr nanomicelles enhanced the antioxidant activity of myricetin (Myr) and inhibited cisplatin-induced proliferation inhibition of HK-2 cells. Moreover, the HS15-Myr nanomicelles inhibited cisplatin-induced reactive oxygen species accumulation, mitochondrial membrane potential reduction, and DNA damage, which might be related to the inhibition of the cyclic GMP−AMP synthase (cGAS)�stimulating interferon gene (STING) signaling pathway. In vivo results in mice showed that the significant reductions in body weight and renal indices and the increased blood urea nitrogen and serum creatinine levels induced by cisplatin could be significantly reversed by pretreating with the HS15-Myr nanomicelles. Furthermore, nanomicelle pretreatment significantly altered the activities of antioxidant enzymes (e.g., GSH, MDA, and SOD) induced by cisplatin. In addition, cisplatin-induced inflammatory responses in mouse kidney tissue were found to be inhibited by pretreatment with HS15-Myr nanomicelles, such as IL-1β and TNF-α expression. The nanomicelles also significantly inhibited cisplatin-induced activation of the DNA damage-cGAS−STING pathway in kidney tissues. Together, our findings suggest that Myr-loaded nanomicelles are potential nephroprotective drugs.

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