Research advances on silence information regulator 6 as a potential therapeutic target for bone regeneration and repair. / æ²‰é»˜ä¿¡æ¯è°ƒèŠ‚å› å­6是骨组织再生修复的潜在作用靶点.

Segmental bone defects and nonunion of fractures caused by trauma, infection, tumor or systemic diseases with limited osteogenesis and prolonged bone healing cycles are challenging issues in orthopedic clinical practice. Therefore, identifying regulatory factors for bone tissue regeneration and metabolism is crucial for accelerating bone repair and reconstructing defective areas. Silence information regulator 6 (SIRT6), functioning as a deacetylase and nucleotide transferase, is extensively involved in the regulation of differentiation, apoptosis, metabolism, and inflammation in bone cells including osteoblasts and osteoclasts, and is considered to be an important factor in regulating bone metabolism. SIRT6 forms a complex with B lymphocyte-induced maturation protein 1 (Blimp1), down-regulates the expression of the nuclear factor κB (NF-κB) pathway, and promotes the expression of the ERα-FasL axis signal to inhibit osteoclast formation and maturation differentiation, thereby hindering bone resorption and increasing bone mass. In addition, SIRT6 activates the Akt-mTOR pathway to regulate the autophagy level and osteogenesis of bone marrow mesenchymal stem cells, inhibits glycolysis and reactive oxygen production in osteoblasts, promotes osteoblast differentiation through the CREB/CCN1/COX2 pathway and the bone morphogenetic protein (BMP) signaling pathway, enhances bone formation, and accelerates bone regeneration and repair of skeletal tissue. This article provides an overview of the research progress on SIRT6 in the pathophysiology of bone regeneration, revealing its potential as a novel therapeutic target for bone tissue repair to alleviate the progression of skeletal pathological diseases.

TGF­ß inhibitor RepSox suppresses osteosarcoma via the JNK/Smad3 signaling pathway.

Osteosarcoma (OS) is the most common malignant bone tumor and the long­term survival rates remain unsatisfactory. Transforming growth factor­ß (TGF­ß) has been revealed to play a crucial role in OS progression, and RepSox is an effective TGF­ß inhibitor. In the present study, the effect of RepSox on the proliferation of the OS cell lines (HOS and 143B) was detected. The results revealed that RepSox effectively inhibited the proliferation of OS cells by inducing S­phase arrest and apoptosis. Moreover, the inhibitory effect of RepSox on cell migration and invasion was confirmed by wound­healing and Transwell assays. Furthermore, western blotting revealed that the protein levels of molecules associated with the epithelial­mesenchymal transition (EMT) phenotype, including E­cadherin, N­cadherin, Vimentin, matrix metalloproteinase (MMP)­2 and MMP­9, were reduced by RepSox treatment. Concurrently, it was also revealed that the JNK and Smad3 signaling pathway was inhibited. Our in vivo findings using a xenograft model also revealed that RepSox markedly inhibited the growth of tumors. In general, our data demonstrated that RepSox suppressed OS proliferation, EMT and promoted apoptosis by inhibiting the JNK/Smad3 signaling pathway. Thus, RepSox may be a potential anti­OS drug.

Chicago sky blue 6B (CSB6B), an allosteric inhibitor of macrophage migration inhibitory factor (MIF), suppresses osteoclastogenesis and promotes osteogenesis through the inhibition of the NF-κB signaling pathway.

Macrophage migration inhibitory factor (MIF) is a pleiotropic pro-inflammatory mediator involved in various pathophysiological and inflammatory states. Accumulating line of evidence suggests a role for MIF in regulating bone metabolism and therefore a prime candidate for therapeutic targeting. In this study, we showed that Chicago sky blue 6B (CSB6B) suppresses RANKL-induced osteoclast and bone resorption in vitro via the inhibition of NF-κB signaling activation and promoting proteasome-mediated degradation of MIF. Consequently, the induction of NFATc1 was impaired resulting in downregulation of NFATc1-responsive osteoclast genes. We also demonstrated that CSB6B treatment enhanced primary calvarial osteoblast differentiation and bone mineralization in vitro via the suppression of NF-κB activation and upregulation of Runx expression. Using two murine models of osteolytic bone disorders, we further showed that administration of CSB6B protected mice against pathological inflammatoryc calvarial bone destruction induced by titanium particles mice as well as estrogen-deficiency induced bone loss as a result of ovariectomy. Together, as an MIF inhibitor, CSB6B can inhibit osteoclast differentiation and bone resorption function and enhance the mineralization of osteoblasts through the inhibition of NF-κB pathway. MIF is a prime target for therapeutic targeting for the treatment of osteolytic bone disorders and the MIF inhibitor CSB6B could be potential anti-osteoporosis drug.

[Expression and clinical significance of plasma small RNA in patients with pancreatic cancer].

OBJECTIVE: The aim of this study was to identify six miRNAs expressed in plasma of patients with pancreatic cancer (PCa) and analyze their value as a diagnostic index of pancreatic cancer. METHODS: Plasma total RNAs were extracted from 30 PCa patients and 26 normal controls, and the abundance of six microRNAs was measured using real-time PCR. The possibility to combine them with CA19-9 as diagnostic biomarkers was analyzed. RESULTS: The expression level of miR-21, miR-210, miR-155, miR-20a, miR-25 and miR-196a in plasma of patients with pancreatic cancer were 1.65×10(6), 5.98×10(4), 2.83×10(3), 3.47×10(6), 2.76×10(6), and 1.03×10(3) (copies/µl), while the normal controls were 4.08×10(5), 2.54×10(4), 8.55×10(2), 1.79×10(6), 9.32×10(5), and 4.67×10(2) (copies/µl), respectively, with a significant difference between the two groups (P < 0.05). The areas under the ROC curve of miR-21, miR-210, miR-155, miR-20a, miR-25 and miR-196a were 0.893, 0.810, 0.820, 0.766, 0.816 and 0.729, respectively. MiR-21 had the highest diagnostic value when it was used as diagnostic marker alone. The combination of miR-155 and miR-25 was more effective to distinguish PCa from normal than to be used alone, and the area under the ROC curve was 0.913 (95%CI 0.838-0.988) .When CA199 associated with miR -210 and miR-25, respectively, the areas under the ROC curves were 0.96 (95%CI was 0-1.0) and 0.942 (95% CI was 0.876-1.0), which were higher than CA199 alone (0.862, 95%CI was 0.748-0.975). There was a high improvement in diagnostic sensitivity and accuracy when miR-210 and miR-25 were combined with CA19-9, respectively. CONCLUSIONS: Plasma miR-21, miR-155, miR-25, miR-210 have diagnostic value for pancreatic cancer, and deserve further study.