Bosutinib Laden Three-Dimensional Printed Zein Scaffolds Promote Osteogenesis

Bone defect repair remains a challenge to be addressed in clinical practice, and existing bone grafting methods still have disadvantages and limitations. Drugs or cytokines laden into bioactive scaffolds to promote bone regeneration is a promising strategy to deal with the problem; thus, it is meaningful to develop drugs and scaffolds with osteogenic abilities. Drug repurposing is an admirable method to find unknown usages of old drugs for enhancing osteogenic differentiation. In this study, by screening an approved drug library consisting of 2040 compounds, bosutinib, a tyrosine kinase inhibitor, was identified to promote osteogenic differentiation in vitro. The observed effect was further confirmed using polymerase chain reaction (PCR), western blot, Alizarin Red staining, and alkaline phosphatase (ALP) activity staining. Subsequently, transcriptome sequencing was performed to elucidate the osteogenesis mechanism of bosutinib, and a potential target gene, Storkhead box 1 (STOX1), which was not reported to be associated with osteogenesis, was found. By a gene knockdown strategy, we provided preliminary evidence that bosutinib can promote osteogenic differentiation by mediating STOX1. Furthermore, in order to maximize the local effects of drug and minimize its side effects, a bosutinib laden three-dimensional (3D)-printed zein scaffold was constructed and characterized, and its ability of promoting osteogenesis was evaluated in vivo. Micro-CT analysis and histological staining demonstrated that the scaffold effectively promoted bone regeneration. All in all, our study provides a therapeutic option for the treatment of bone defects.