Osteosarcoma is the most common malignant bone tumor. It has a poor prognosis because of a lack of therapeutic targets and strategies. The SET domain-containing lysine-specific methyltransferase, SET7/9, has various functions in different cancer types in tissue-type and signaling context-dependent manners. The role of SET7/9 in osteosarcoma cells is currently controversial and its potential as a therapeutic candidate in osteosarcoma is unknown. In the present study, SET7/9 inhibition or ablation suppressed osteosarcoma cell proliferation by causing G1 arrest. Mechanistically, SET7/9 inhibition disrupted the interaction between cyclin-dependent kinase 4 (CDK4) and cyclin D1, which affected CDK4-cyclin D1 complex function, leading to decreased phosphorylation of retinoblastoma protein. CDK4 was overexpressed in osteosarcoma tissues and was closely related to a poor prognosis in patients with osteosarcoma. We therefore hypothesized that SET7/9 inhibition might increase the sensitivity of osteosarcoma cells to CDK4 inhibitors, potentially decreasing the risk of adverse effects of CDK4 inhibitors. The combination of SET7/9 and CDK4 inhibition enabled dose reductions of both inhibitors and had a synergistic effect against osteosarcoma growth in vivo. Collectively, these findings indicate that SET7/9 plays an oncogenic role in osteosarcoma by regulating CDK4-cyclin D1 complex interaction and function. The combination of SET7/9 and CDK4 inhibition may thus provide a novel effective therapeutic strategy for osteosarcoma with no significant toxicity.

Centromere localization of the chromosome passenger complex (CPC) is paramount for achieving accurate sister chromosome segregation in mitosis. Although it has been widely recognized that the recruitment of CPC is directly regulated by two histone codes, phosphorylation of histone H3 at threonine 3 (H3T3ph) and phosphorylation of histone H2A at threonine 120 (H2AT120ph), the regulation of CPC localization by other histone codes remains elusive. We show that dysfunction of disruptor of telomeric silencing 1 like (DOT1L) leads to mislocation of the CPC in prometaphase, caused by disturbing the level of H3T3ph and its reader Survivin. This cascade is initiated by over-dephosphorylation of H3T3ph mediated by the phosphatase RepoMan-PP1, whose scaffold RepoMan translocalizes to chromosomes, while the level of H3K79me2/3 is diminished. Together, our findings uncover a biological function of DOT1L and H3K79 methylation in mitosis and give insight into how genomic stability is coordinated by different histone codes.

自噬是受到精密调控的细胞自我更新过程，表观遗传调控是自噬的重要调控机制。作为常见的表观遗传调控酶，赖氨酸特异性去甲基化酶1（lysine-specific demethylase 1,LSD1）是生物治疗的靶点与研究热点。LSD1在转录水平与翻译后修饰水平对自噬相关分子的调控，在炎症转归、肿瘤进展、细胞存亡等生物学过程中发挥着重要作用。因此，综述LSD1调控自噬的机制对于探索疾病治疗的新靶点并丰富疾病的治疗方案具有重要参考意义。

高黄芩素是从灯盏细辛、木蝴蝶、野菊花等中草药提取出的天然黄酮类单体成分,具有抗氧化、抗炎的生物学作用,已用于哮喘、风湿病、糖尿病、神经性疾病等临床疾病的治疗.近年来,高黄芩素在抗肿瘤方面的作用被逐渐的认识,研究发现,高黄芩素在胃癌、肝癌、结肠癌、肺癌、多发性骨髓瘤等恶性肿瘤中表现出显著的抑瘤作用,其抑瘤机制主要包括促进肿瘤细胞凋亡、抑制肿瘤细胞增殖、阻碍肿瘤细胞的周期进程、抑制肿瘤细胞迁移与侵袭、遏制肿瘤血管新生等.另外,高黄芩素具有生物利用度高、可靶向选择肿瘤细胞等特点,表明高黄芩素是潜在的重要肿瘤化疗药物.目前,尚缺乏高黄芩素抗肿瘤作用及机制的研究进展荟萃,本文就近年来国内外有关高黄芩素的抗肿瘤作用及分子机制进行综述,以期为高黄芩素的实验室研究与临床应用提供科学参考与思路.

Bone healing is a complex and orchestrated process, involving in inflammation, angiogenesis, mesenchymal stem cells differentiation, vascular endothelial cells and skeletal cells proliferation and cell autophagy. The individualized differences of patients including risk factors, combined with the perspective of phenotype can provide a novel view for the treatment of bone unhealing. Bone morphogenetic protein-2 (BMP-2), fibroblast growth factor-2 (FGF-2), runt-related transcription factor 2 (RUNX2) and vascular endothelial growth factor (VEGF) take part in multiple phenotypes of bone healing, thus these candidates are the main treatment targets of bone unhealing. Taking advantage of these phenotypes and molecular mechanisms is beneficial for the understanding of mechanisms of fracture healing and helpful for the transformation from laboratory research to the clinical application. Here we characterized the main phenotypes and mechanisms in the treatment of bone unhealing.

4D生物制造是近年发展起来的一种新兴技术，其基于3D生物打印，将第四维度"时间"融入其中，使用的智能生物打印材料具有响应环境刺激的能力，使其对所制造的构件既有空间控制，又有时间控制，可以更准确地模拟自然组织的动态变化，在再生医学领域创建高分辨率的复杂动态结构方面具有巨大的潜力。

Few studies have characterized the clinical outcomes of 45S5 Bioglass® applied as a bone graft to that of allogeneic bone applied in calcaneal open curettage. Therefore, the purpose of the present investigation was to compare the outcomes of patients with calcaneal tumors and tumor-like lesions treated by open curettage with 45S5 Bioglass® or allogeneic bone. Of the 31 patients who underwent open curettage (18 cases of unicameral bone cysts, 7 cases of aneurysmal bone cysts, and 6 cases of intraosseous lipoma), 16 (52%) received grafts with 45S5 Bioglass® and 15 (48%) with allogeneic bone. All the feet achieved bone fusion according to the modified Neer radiographic classification system at the last follow-up examination. The mean bone ingrowth time for the grafts with 45S5 Bioglass® versus allogeneic bone was 3.71 ± 0.86 versus 4.46 ± 1.04 months (p = .038), the mean bone healing time was 4.86 ± 0.93 versus 5.73 ± 1.07 months (p = .021), and the mean incision drying time was 7.2 ± 1.8 versus 8.2 ± 1.5 days (p = .047), respectively. No differences were found in the postoperative American Orthopaedic Foot and Ankle Society ankle-hindfoot scale scores between the 2 groups (p = .213). These results show that 45S5 Bioglass® can better facilitate the formation of new bone with a faster drying time of the incision than allogeneic bone. Although both materials can benefit the clinical outcomes of calcaneal tumors and tumor-like lesions, further studies are needed to observe the long-term complications and lesion recurrence rates.

Lysine-specific demethylase 1 (LSD1) is a well characterized transcriptional regulator functioning on the chromatin to remove mono- and di-methyl groups from lysine 4 or lysine 9 of histone 3 (H3K4 or H3K9). LSD1 also has non-transcriptional activities via targeting non-histone substrates that participate in diverse biological processes. In this report, we determined that LSD1 negatively regulates autophagy in skeletal muscle cells by promoting PTEN degradation in a transcription-independent mechanism. In C2C12 cells, LSD1 inhibition or depletion significantly induced the initiation of autophagy; and autophagy resulted from LSD1 inhibition is associated with AKT/mTORC1 inactivation. Notably, the proteins of PTEN, a prominent repressive AKT modulator, are stabilized by LSD1 inhibition despite a decrease of its mRNA levels. Further data demonstrated that LSD1 interacts with PTEN protein and enhances its ubiquitination and degradation. Together, our findings identify a novel biological function of LSD1 in autophagy, mediated by regulating the stability of PTEN and the activity of AKT/mTORC1.

The proliferation and differentiation of myoblast cells are regulated by the fibroblast growth factor receptor (FGFR) signaling pathway. Although the regulation of FGFR signaling cascades has been widely investigated, the inhibitory mechanism that particularly function in skeletal muscle myogenesis remains obscure. In this study, we determined that LRTM1, an inhibitory regulator of the FGFR signaling pathway, negatively modulates the activation of ERK and promotes the differentiation of myoblast cells. LRTM1 is dynamically expressed during myoblast differentiation and skeletal muscle regeneration after injury. In mouse myoblast C2C12 cells, knockout (KO) of Lrtm1 significantly prevents the differentiation of myoblast cells; this effect is associated with the reduction of MyoD transcriptional activity and the overactivation of ERK kinase. Notably, further studies demonstrated that LRTM1 associates with p52Shc and inhibits the recruitment of p52Shc to FGFR1. Taken together, our findings identify a novel negative regulator of FGFR1, which plays an important role in regulating the differentiation of myoblast cells.

目的:利用CRISPR/Cas9技术构建稳定敲除Lrtm1 (leucine-rich repeats and transmenbrane domains 1)基因的C2C12细胞系,为研究Lrtm1基因的作用提供实验基础.方法:设计3对针对Lrtm1基因的向导RNA(sgRNA),将sgRNA插入载体pCRISPR-LvSG06中;利用慢病毒包装系统包装含有sgRNA的重组质粒pCRISPR-LvSG06;将病毒感染C2C12细胞,并加入嘌呤霉素筛选,将筛选嘌呤霉素阳性的细胞提取RNA,逆转录成cDNA;设计Cas9引物,利用cDNA为模版,PCR验证C2C12细胞中Cas9的表达,确认慢病毒成功感染C2C12细胞;利用96孔板挑选单克隆细胞的方法筛选得到单克隆细胞;将扩增的单克隆细胞提取基因组DNA,测序Lrtm1基因相关序列并与野生型Lrtm1基因进行对比,确认敲除成功的克隆细胞株;诱导敲除Lrtm1稳定细胞株成肌分化,检测成肌分化标志因子Myosin的蛋白表达,RT-PCR检测转录因子PAX7的mRNA表达,Western blot检测H3K27me3蛋白水平.结果:测序结果显示向导RNA(sgRNA)成功插入载体质粒;将单克隆细胞DNA测序结果显示A和C克隆成功敲除Lrtm1基因;敲除Lrtm1基因后成肌分化标志因子Myosin蛋白表达降低,成肌转录因子PAX7 mRNA的表达降低,在分化72和96 h组,H3K27me3蛋白水平较野生型组增高.结论:利用CRISPR/Cas9技术成功敲除Lrtm1基因,稳定敲除Lrtm1基因的C2C12细胞系构建成功;敲除Lrtm1后能抑制C2C12细胞成肌分化,并且抑制成肌转录因子PAX7的mRNA表达,PAX7mRNA表达降低的原因可能为H3K27me3水平增高.

Diabetes is a chronic disease that disrupts the balance between bone formation and bone desorption, which can lead to osteoporosis, increasing the risk of fracture. However, compared with osteoblasts, the biological effects of hyperglycemia on osteoclastogenesis remain to be elucidated. Therefore, we investigated the impact of glucose at different concentrations (5.5, 10.5, 15.5, 20.5, 25.5, and 30.5 mM) on osteoclastogenesis using RAW264.7 cells. Cell proliferation was measured with the cell counting kit-8 assay, and osteoclastogenesis was detected with tartrate-resistant acid phosphatase staining and bone resorption assays, as well as protein cathepsin K expression. Compound C, the AMP-activated protein kinase (AMPK) pathway inhibitor, was used to examine the relationship between the AMPK/mTOR/ULK1 signaling pathway and autophagy in osteoclasts. Autophagy was evaluated with transmission electron microscopy and immunofluorescence microscopy and associated proteins were detected with western blotting. The pharmacological autophagic reagents bafilomycin A1, 3-methyladenine, and rapamycin were used to determine the effect of autophagy on osteoclastogenesis. Our results showed that glucose negatively affected osteoclast formation and function but did not affect the proliferation of RAW264.7 cells. Suppression of the AMPK/mTOR/ULK1 signaling axis decreased autophagy in glucose-mediated osteoclast. Furthermore, High levels of glucose decreased autophagy level in osteoclasts. Additionally, interfering with autophagy affected osteoclast formation and function. These findings clarify the mechanisms underlying the effects of glucose-mediated osteoclastogenesis and will help identify novel therapeutic strategies for the protection of skeletal health in diabetic osteoporosis.

Objective To evaluate the clinical outcomes of the talonavicular and calcaneocuboid arthrodesis for the treatment of Müller-Weiss disease.Methods From September 2010 to May 2015,13 feet of 13 patients with Müller-Weiss disease were treated in our department by talonavicular and calcaneocuboid arthrodesis.Talonavicular joints were fused by compressed hollow screws,and stables were used to fix calcaneocuboid joints.The AOFAS score was applied to evaluate the function of hindfoot,while the Meary angle and calcaneal angle were measured to assess the relocation of foot tarsal bones.Results All patients were followed up from 16.0 to 21.5 months (average,19 months),during the follow-up period,the subtalar and naviculocuneiform joints were not significantly affected according to the radiographic images.All feet achieved bone fusion with the mean time of 14 weeks (ranged from 11 to 19 weeks).Four patients complained the uncomfortable feeling when walking on uneven ground,one incision of a patient was infected and healed finally after the symptomatic treatment.There were significant differences between the last follow-up values and the preoperative values in the AOFAS score,Meary angle and calcaneal angle (P ＜0.05).Conclusion Talonavicular and calcaneocuboid arthrodesis may achieve favorable outcomes in terms of deformity correction,pain relief,and functional restoration,but the part motion of hindfoot is lost,and the function of hindfoot during walking or running is affected,too.We consider this technique as our treatment choice in patients with Maceira stage Ⅲ and stage Ⅳ Müller-Weiss disease.

目的:探讨重组人促红细胞生成素(recombinant human erythropoietin,rHuEPO)促进痛风石切除术后患者切口愈合和贫血恢复的疗效及机制.方法:2014年6月至2015年8月,30例痛风石切除术后贫血的患者随机分成两组,试验组注射rHuEPO,对照组注射等量生理盐水,余治疗相同.记录并比较两组患者术后切口愈合、红细胞(RBC)、血红蛋白(Hb)等相关指标,分析rHuEPO对痛风石切除术后贫血患者切口愈合和贫血恢复的作用及机制.结果:试验组和对照组的切口平均干燥时间、切口平均愈合时间、切口健康等级优良率差异均有统计学意义(P＜0.05),试验组术后第2周、术后1个月复查时的Hb和RBC与对照组相比差异有统计学意义(P＜0.05).结论:rHuEPO能够促进痛风石切除术后贫血患者手术切口愈合和贫血恢复,且无明显不良反应.