[Regulation of Wnt/β-catenin signaling in bone development and bone tumor]

Expression pattern and clinical significance of β-catenin gene and protein in patients with primary malignant and benign bone tumors

This study is aimed to unravel the status of local and circulating β-catenin in different primary bone tumors and its relevance to tumor types, severity, and chemotherapy. The β-catenin mRNA expression level and the expression of the protein (intensity level) were evaluated in tumor tissue and peripheral blood mononuclear cells of 150 patients with different types of primary bone tumors (78 malignant and 72 benign tumors) using Real-Time PCR and immunohistochemistry. The β-catenin mRNA expression level and the expression of the protein were increased in bone tumors which was positively correlated with the tumor malignancy. Amongst osteosarcoma, Ewing's Sarcoma, chondrosarcoma, osteochondroma, Giant Cell Tumor, and exostosis tumors, the osteosarcoma, and Giant Cell Tumor groups showed the highest level of β-catenin expression. The β-catenin expression in malignant bone tumors was significantly correlated with tumor grade, size, metastasis, tumor recurrent, and the level of response to chemotherapy. A similar pattern of β-catenin gene expression and its association with tumor characteristics was detected in the patient's peripheral blood cells. The simultaneous increase in the expression of the β-catenin gene and protein in tumor tissue and in circulating blood cells and its relationship with tumor severity indicates the possible promoting role of β-catenin in primary bone tumor pathogenesis.

The Aqueous Extract of Eucommia Leaves Promotes Proliferation, Differentiation, and Mineralization of Osteoblast-Like MC3T3-E1 Cells

Eucommia leaves are dry leaves of Eucommia ulmoides which have long been considered as a functional health food for the treatment of hypertension, hypercholesterolemia, fatty liver, and osteoporosis. With the recent development of Chinese medicine, Eucommia leaves are widely used for tonifying the kidneys and strengthening bone. However, the specific molecular mechanism of Eucommia leaves for strengthening bone remains largely unknown. Osteoblasts are the main functional cells of bone formation; thus, it is essential to study the effect of Eucommia leaves on osteoblasts to better understand their mechanism of action. In the present study, we prepared an aqueous extract of Eucommia leaves (ELAE) and determined its content by high-performance liquid chromatography (HPLC). The effects of ELAE on MC3T3-E1 cells were investigated by CCK-8 assay, alkaline phosphatase (ALP), and Alizarin red S staining assays, combined with RNA sequencing (RNA-seq) and qRT-PCR validation. We demonstrated that ELAE had a significant promoting effect on the proliferation of MC3T3-E1 cells and significantly enhanced extracellular matrix synthesis and mineralization, which were achieved by regulating various functional genes and related signaling pathways. ELAE significantly increased the expression level of genes promoting cell proliferation, such as Rpl10a, Adnp, Pex1, Inpp4a, Frat2, and Pcdhga1, and reduced the expression level of genes inhibiting cell proliferation, such as Npm1, Eif3e, Cbx3, Psmc6, Fgf7, Fxr1, Ddx3x, Mbnl1, and Cdc27. In addition, ELAE increased the expression level of gene markers in osteoblasts, such as Col5a2, Ubap2l, Dkk3, Foxm1, Col16a1, Col12a1, Usp7, Col4a6, Runx2, Sox4, and Bmp4. Taken together, our results suggest that ELAE could promote osteoblast proliferation, differentiation, and mineralization and prevent osteoblast apoptosis. These findings not only increase our understanding of ELAE on the regulation of bone development but also provide a possible strategy to further study the prevention and treatment of osteogenic related diseases by ELAE.