Global Identification of Anti-Melanoma Cellular Targets by Photochemically Induced Coupling of L-Shikonin Reactions on the Surface of Magnetic Particles

Background:L-Shikonin, an active component of Arnebia euchroma (Royle) Johnst., has remarkable pharmacological effects, particularly in its anti-tumour activity. Nonetheless, the specific targets and mechanisms of action remain to be further explored.Methods:A novel Fe3O4@L-Shikoninwas designed and synthesized in this study by linking Fe3O4andL-Shikoninthrough benzophenone. Fe3O4@L-Shikoninwas characterized using several techniques, including scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and drug removal methods, to determine the content ofL-Shikoninon the surface of the magnetic particles. Target hooking technology was utilized to identify the target proteins of the compound in melanoma. The synthesized Fe3O4@L-Shikoninwas co-incubated with A375 cell lysate, followed by the target proteins, which were purified by magnetic enrichment using magnetic microspheres and identified by high-resolution mass spectrometry.Results:AutoDock Vina software was employed for molecular docking analysis, where it was found thatL-Shikonintargets RPN1, CPEB4, and HNRNPUL1 proteins. Subsequently, A375 cells were treated withL-Shikoninat different concentrations (2.5, 5.0, 10.0 μM) for 48 h, and the expressions of the three proteins were observed. The results showed a significant reduction in the relative expression of CPEB4 in the high-dose group compared to the control group (p< 0.01). Moreover, the relative expression of HNRNPUL1 was decreased in the medium- and high-dose groups (p< 0.05).Conclusions:This study initially revealed from the source thatL-Shikoninmay regulate melanoma-specific markers, melanosomes, tyrosine kinases related to abnormal tyrosine metabolism, and melanoma through multiple targets such as CPEB4 and HNRNPUL1. Proliferation and metastasis work together to exert an anti-melanoma mechanism, which provides a new idea for the follow-up study of the molecular pharmacological mechanism of the complex system of total naphthoquinones inArnebia euchroma(Royle) Johns.