Osteosarcoma (OS) is one of the most common malignant tumors in adolescents. Due to local invasion, distant metastasis and drug resistance, the clinical treatment efficacy and prognosis of OS have remained almost unchanged for decades. Epigallocatechin-3-gallate (EGCG) is a unique catechin from tea leaves, and some studies have confirmed its antitumour effects on various tumors. Here, cellular experiments showed that EGCG significantly promoted OS cell apoptosis and inhibited proliferation, migration and invasion, and cell and animal experiments demonstrated that the Wnt/β-catenin pathway played an indispensable role in the antitumour effects of EGCG. Moreover, EGCG inhibited the growth of OS cells in vitro while suppressing tumor cell damage to the bone in situ and distant lung metastasis. The results indicate that the antitumour effect of EGCG on human OS may be mediated by regulating the Wnt/β-catenin pathway and that EGCG can be used alone or in combination with other regimens as a potentially effective anticancer treatment.

BACKGROUND: The incidence of osteoporosis and osteoporotic fractures is increasing every year. Traditional Chinese Medicine (TCM) can shed new light on the treatment of osteoporosis. This study aimed to explore the role and mechanism of paeoniflorin in promoting osteogenic differentiation of an osteoblast precursor cell line (MC3T3-E1).
METHODS: MC3T3-E1 cells were cultured in osteogenic induction medium (OIM) and OIM combined with different concentrations of paeoniflorin. The optimal dose of paeoniflorin was assessed by a cell counting kit-8 (CCK-8) assay. Then, alkaline phosphatase (ALP) and Alizarin Red S (ARS) staining were performed to assess the osteogenic capacity of paeoniflorin. The transcription of osteogenic genes and the expression of osteogenic proteins were assessed by RT-PCR and Western blotting, respectively. The transcription of Wnt/β-catenin signaling pathway genes and proteins was assessed by RT-PCR and Western blotting, respectively. Finally, Dickkopf-1 (DKK-1), a Wnt/β-catenin signaling pathway inhibitor, was used to identify whether the Wnt/β-catenin signaling pathway was involved in the osteogenic differentiation of paeoniflorin. Osteoclastogenesis in RAW264.7 cells was identified by tartrate-resistant acid phosphatase (TRAP) staining.
RESULTS: At concentrations ranging from 0.1 to 100 μM, paeoniflorin was not cytotoxic to MC3T3-E1 cells. Paeoniflorin significantly increased the osteogenic differentiation of MC3T3-E1 cells in a dose-dependent manner. Moreover, paeoniflorin significantly increased osteogenic differentiation gene and protein expression. Through bioinformatic analysis, paeoniflorin-affected genes were found to be involved in different signaling pathways, such as the Wnt/β-catenin signaling pathway. Paeoniflorin enhanced β-catenin and CyclinD1 expression compared with that of the control groups. DKK-1 partially reversed the promoting effects of paeoniflorin in promoting osteogenic differentiation of MC3T3-E1 cells. Moreover, paeoniflorin inhibited the osteoclastogenesis of RAW264.7 cells.
CONCLUSIONS: Paeoniflorin promotes osteogenic differentiation in MC3T3-E1 cells by regulating the Wnt/β-catenin pathway. Paeoniflorin is a potential therapeutic agent for the treatment of osteoporosis.

BACKGROUND: The antimicrobial peptide LL-37, in addition to its broad spectrum of antibacterial function, can promote odontogenesis and osteogenesis. Stem cells from the apical papilla (SCAPs) are essential for the formation of dentin/bonelike tissues. However, little information on these cells is available in regenerative endodontics. This study aimed to evaluate the effects of LL-37 on the proliferation, migration, and differentiation of SCAPs.
METHODS: SCAPs were isolated, cultured, and characterized. Cell viability was analyzed by Cell Counting Kit-8 assays (Dojindo, Kumamoto, Japan). Cell migration was investigated by transwell assays. Dentin sialophosphoprotein, dentin matrix protein 1, runt-related transcription factor 2, and osterix were assessed by quantitative polymerase chain reaction and Western blots. Alkaline phosphatase (ALP) activity and ALP staining were assessed to determine the in vitro potential for osteogenic differentiation. The involvement of the Akt/Wnt/β-catenin signaling pathway was also studied.
RESULTS: In the 2.5-μg/mL LL-37 -treated group, cell proliferation and migration were up-regulated. Quantitative polymerase chain reaction and Western blot assays both revealed that LL-37 at 2.5 μg/mL up-regulated odonto/osteogenic markers (dentin sialophosphoprotein, dentin matrix protein 1, runt-related transcription factor 2, and osterix). LL-37 at 2.5 μg/mL significantly promoted ALP activity and increased the staining in SCAPs. In addition, the p-Akt and p-glycogen synthase kinase-3β levels were increased in LL-37-treated SCAPs. The migratory and odonto/osteogenic differentiation capacities of SCAPs were inhibited after treatment with inhibitors LY294002 and XAV-939.
CONCLUSIONS: Our study showed that LL-37 at 2.5 μg/mL promoted the migration and odonto/osteogenic differentiation of SCAPs by activating the Akt/Wnt/β-catenin signaling pathway.

In indirect co-culture system, chondrocytes can induce differentiation of bone marrow mesenchymal stem cells (BMSCs) to chondrocytes without additional inducer. The participation of microRNAs (miRNAs) may take part in the chondrogenic differentiation. Present study aimed to investigate the effect and mechanism of chondrocytes-derived exosomal miRNA in BMSCs chondrogenic differentiation. Our data showed that miR-8485 was the exosomal miRNA derived from chondrocytes and transmitted to BMSCs. Functionally, miR-8485 silence in chondrocytes impaired exosome-induced chondrogenic differentiation of BMSCs. Mechanistically, exosomal miR-8485 targeted GSK3B to repress GSK-3β expression and targeted DACT1 to induce p-GSK-3β (Ser9), activating Wnt/β-catenin pathways. Our study firstly showed that chondrocytes-derived exosomal miR-8485 regulated the Wnt/β-catenin pathways to promote chondrogenic differentiation of BMSCs, providing innovative thoughts for cartilage reconstruction.

It is reported that black raspberry (BRB) anthocyanins could act as a potential chemopreventive agent for colorectal cancer (CRC). However, the underlying mechanism by which BRB anthocyanins inhibits the carcinogenesis of CRC cells has not been elucidated. The abnormal expression of microRNAs (miRNAs) that target important tumor suppressor genes is usually associated with CRC development. In this study, we explored whether BRB anthocyanins could affect the expression of certain miRNAs in an azoxymethane (AOM)/dextran sulphate sodium (DSS)-induced CRC mouse model and human CRC cell lines. miRNA microarray analysis was used to determine the differences in miRNA expression between AOM/DSS-induced mice fed with a diet supplemented without or with BRB anthocyanins. The expression of one particular miRNA, miR-483-3p, was found to decrease dramatically in AOM/DSS-induced mice that were fed with a diet supplemented with BRB anthocyanins. Subsequent quantitative real-time polymerase chain reaction and Western blot analyses showed that the reduced expression of miR-483-3p was accompanied by an increased expression of Dickkopf 3 (DKK3), a potential target of miR-483-3p as predicted by bioinformatic analysis. The protein and messenger RNA levels of DKK3 were significantly upregulated when the miR-483-3p level was reduced by a miR-483-3p-specific inhibitor, suggesting that DKK3 might be the target gene of miR-483-3p. In addition, the downstream factors of the DKK3 signaling pathway, which included Wnt/β-catenin, also played a role in the miR-483-3p-mediated anticancer effect of BRB anthocyanins. Thus, miR-483-3p might be a potential target in BRB anthocyanin-mediated prevention of CRC.

Cerebral ischemia-reperfusion injury (IRI) potentiates existing brain damage and increases mortality and morbidity via poorly understood mechanisms. The aim of our study is to investigate the role of Sirtuin 3 (Sirt3) in the development and progression of cerebral ischemia-reperfusion injury with a focus on mitochondrial fission and the Wnt/β-catenin pathway. Our data indicated that Sirt3 was downregulated in response to cerebral IRI. However, the overexpression of Sirt3 reduced the brain infarction area and repressed IRI-mediated neuron apoptosis. Functional assays demonstrated that IRI augmented mitochondrial fission, which induced ROS overproduction, redox imbalance, mitochondrial pro-apoptotic protein leakage, and caspase-9-dependent cell death pathway activation. However, the overexpression of Sirt3 blocked mitochondrial fission and induced pro-survival signals in neurons subjected to IRI. At the molecular level, our data further illustrated that the Wnt/β-catenin pathway is required for the neuroprotection exerted by Sirt3 overexpression. Wnt/β-catenin pathway activation via inhibiting β-catenin phosphorylation attenuates mitochondrial fission and mitochondrial apoptosis. Collectively, our data show that cerebral IRI is associated with Sirt3 downregulation, Wnt/β-catenin pathway phosphorylated inactivation, and mitochondrial fission initiation, causing neurons to undergo caspase-9-dependent cell death. Based on this, strategies for enhancing Sirt3 activity and activating the Wnt/β-catenin pathway could be therapeutic targets for treating cerebral ischemia-reperfusion injury.