TET3 Protein Represses Proliferation of the MG-63 Human Osteosarcoma Cell Line by Regulating DNA Demethylation: an Epigenetic Study.

Recent studies have highlighted the significant role of 5-hydroxymethylcytosine (5hmC) in carcinogenesis. However, the specific role of 5hmC in osteosarcoma (OS) remains largely unexplored. The-re-fore, this study aimed to investigate the function of 5hmC and TET3 in OS. In this study, we found a decreased total level of 5hmC in OS tissues. The expression of the TET3 protein was also decreased in OS. Importantly, the decreased levels of TET3 were associated with a decreased disease-free survival (DFS) rate in patients. To investigate the role of TET3 and 5hmC in OS, we manipulated the levels of TET3 in MG-63 cells. Silencing TET3 in these cells resulted in a twofold increase in proliferation. Additio-nally, the level of 5hmC decreased in these cells. Con-versely, over-expression of TET3 in MG-63 cells led to the expected inhibition of proliferation and invasion, accompanied by an increase in 5hmC levels. In conclusion, both 5hmC and TET3 protein levels were decreased in OS. Additionally, the over-expression of TET3 inhibited the proliferation of MG-63 cells, while the suppression of TET3 had the opposite effect. These findings suggest that decreased levels of 5hmC and TET3 may serve as potential markers for OS.

Potential role of m6A RNA methylation regulators in osteosarcoma and its clinical prognostic value.

BACKGROUND: Osteosarcoma is a disease with high mortality in children and adolescents, and metastasis is one of the important clinical features of osteosarcoma. N6-Methyladenosine (m6A) is the most abundant methylation modification in mRNA, which is regulated by m6A regulators. It is reported that it is related to the occurrence and development of tumors. However, the mechanism of its action in osteosarcoma is rarely known. The purpose of this study was to identify the potential role of m6A regulatory factor in osteosarcoma and its clinical prognostic value. METHODS: Here, we used The Cancer Genome Atlas (TCGA) to comprehensively analyze the relationship between m6A regulatory factors and osteosarcoma (metastasis group and non-metastasis group). We analyzed their survival relationship and analyzed all the m6A regulatory factors in TCGA tumor data set by using the univariate Cox proportional hazard regression model. Finally, we selected two survival-related methylation regulators (FTO and IGF2BP2) as risk gene signature. RESULTS: According to the median risk, patients were divided into low-risk group and high-risk group. Multivariate Cox regression analysis showed that these two risk genes were considered to be the key factors independently predicting the prognosis of patients with osteosarcoma. In addition, we verified their characteristics with gene expression omnibus (GEO) DataSets and confirmed that they are related to tumor and immune-related signaling pathways through gene set enrichment analysis (GESA) and immune infiltration analysis. CONCLUSIONS: In conclusion, m6A regulators might play an important role in the metastasis of osteosarcoma and have potential important value for the prognosis and treatment strategy of osteosarcoma patients.

miR­23b­3p promotes the apoptosis and inhibits the proliferation and invasion of osteosarcoma cells by targeting SIX1.

Osteosarcoma (OS) is the most common primary malignant bone tumor and the third most common cancer that occurs during childhood and adolescence. Increasing evidence has suggested that microRNA (miR)­23b­3p has an important role in OS tumorigenesis; however, the underlying molecular mechanisms remain unknown. The aim of the present study was to investigate the expression levels of miR­23b­3p and sine oculis homeobox homolog 1 (SIX1) in OS tissues and cell lines (MG­63, SaOS­2 and U2OS), as well as to observe the effects of miR­23b­3p on U2OS cell viability, cell cycle, apoptosis and invasive ability. The results revealed that the expression levels of miR­23b­3p were significantly decreased in OS tissues and cell lines compared with tumor­adjacent normal tissues and a non­cancerous human fetal osteoblastic cell line (hFOB1.19). To investigate the underlying mechanisms of miR­23b­3p in OS tumorigenesis and progression, human U2OS cell lines over­ or under expressing miR­23b­3p were established. The effects of miR­23b­3p on U2OS cell viability, cell cycle, apoptosis and invasion properties were determined by performing Cell Counting Kit­8, flow cytometry and Transwell invasion assays. miR­23b­3p was revealed to suppress cell viability, proliferation and invasion, and to enhance the levels of cell apoptosis. Furthermore, SIX1 mRNA and protein expression levels in OS tissues and cell lines were significantly upregulated when compared with tumor­adjacent normal tissues and hFOB 1.19 cells, which suggested that SIX1 expression levels may be inversely associated with miR­23b­3p levels in OS. Luciferase reporter system analysis demonstrated that miR­23b­3p binds to the SIX1 3'­untranslated region. miR­23b­3p downregulation contributed to SIX1 upregulation, which facilitated the potentiation of cyclin D1 and vascular endothelial growth factor­C expression levels, as well as the inhibition of caspase­3 expression. Collectively, these results suggested that miR­23b­3p is downregulated and SIX1 is upregulated in OS cells, and that miR­23b­3p inhibition may suppress the proliferation and invasion of OS cells, and contribute to cell apoptosis via negative regulation of SIX1. miR­23b­3p/SIX1 may therefore represent a potential target for the treatment of OS.

Low concentration of sodium bicarbonate improves the bioactive compound levels and antioxidant and α-glucosidase inhibitory activities of tartary buckwheat sprouts.

This study aimed to investigate the effects of different concentrations of sodium bicarbonate (NaHCO3) on the accumulation of flavonoids, total phenolics and d-chiro-inositol (DCI), as well as the antioxidant and α-glucosidase inhibitory activities, in tartary buckwheat sprouts. Treatment with low concentrations of NaHCO3 (0.05, 0.1, and 0.2%) resulted in an increase in flavonoids, total phenolic compounds and DCI concentrations, and improved DPPH radical-scavenging and α-glucosidase inhibition activities compared with the control (0%). The highest levels of total flavonoids (26.69mg/g DW), individual flavonoids (rutin, isoquercitrin, quercetin, and kaempferol), total phenolic compounds (29.31mg/g DW), DCI (12.56mg/g DW), as well as antioxidant and α-glucosidase inhibition activities, were observed in tartary buckwheat sprouts treated with 0.05% NaHCO3 for 96h. These results indicated that appropriate treatment with NaHCO3 could improve the healthy benefits of tartary buckwheat sprouts.