RANKL,a necessary chance for clinical application to osteoporosis and cancer-related bone diseases

Osteoporosis is a common bone disease characterized by reduced bone and increased risk of fracture. In postmenopausal women, osteoporosis results from bone loss attributable to estrogen deficiency. Osteoclast differentiation and activation is mediated by receptor activator of nuclear factor-κB ligand (RANKL), its receptor receptor activator of nuclear factor-κB (RANK), and a decoy receptor for RANKL, osteoprotegerin (OPG). The OPG/RANKL/RANK system plays a pivotal role in osteoclast biology. Currently, a fully human anti-RANKL monoclonal antibody named denosumab is being clinically used for the treatment of osteoporosis and cancer-related bone disorders. This review describes recent advances in RANKL-related research, a story from bench to bedside. First, the discovery of the key factors, OPG/RANKL/RANK, revealed the molecular mechanism of osteoclastogenesis. Second, we established three animal models: (1) a novel and rapid bone loss model by administration of glutathione-S transferase-RANKL fusion protein to mice; (2) a novel mouse model of hypercalcemia with anorexia by overexpression of soluble RANKL using an adenovirus vector; and (3) a novel mouse model of osteopetrosis by administration of a denosumab-like anti-mouse RANKL neutralizing monoclonal antibody. Lastly, anti-human RANKL monoclonal antibody has been successfully applied to the treatment of osteoporosis and cancer-related bone disorders in many countries. This is a real example of applying basic science to clinical practice.     

Historically significant events in the discovery of RANK/RANKL/OPG

After it was suggested 30 years ago that the osteoblast lineage controlled the formation of osteoclasts, methods were developed that established this to be the case, but the molecular controls were elusive. Over more than a decade much evidence was obtained for signaling mechanisms that regulated the production of a membrane - bound regulator of osteoclastogenesis, in the course of which intercellular communication in bone was revealed in its complexity. The discovery of regulation by tumor necrosis factor ligand and receptor families was made in the last few years of the twentieth century, leading since then to a new physiology of bone, and to exciting drug development.     

骨水泥填充内固定联合二磷酸盐治疗邻膝关节骨巨细胞瘤

[目的]探讨采用病灶内肿瘤扩大刮除、骨水泥填充并钢板内固定联合二磷酸盐治疗邻膝关节骨巨细胞瘤的临床应用可行性.[方法]回顾分析2008年1月～2010年6月本科治疗的16例邻膝关节骨巨细胞瘤.男7例,女9例,平均年龄38岁(27～78岁).发病部位:股骨远端10例,胫骨近端6例.所有患者术前均经仔细评估确定肿瘤腔的完整性,术中仔细刮除肿瘤组织,应用磨钻及电刀处理瘤腔壁,骨水泥填充修复骨缺损,同时给予钢板内固定.术后均应用二膦酸盐类药物.[结果]本组患者全部获得随访,中位随访15个月,无局部复发及转移发生.参照Enneking肢体功能评分标准,本组患者平均得29分(27～30)分.复查X线片示所有患者内固定均牢靠,无软骨下骨骨折.[结论]对于膝关节周嗣骨巨细胞瘤可以选择病灶扩大刮除、骨水泥充填内固定联合二膦酸盐类药物治疗,该方法具有操作简单、肢体功能恢复理想、近期复发率低、病人易于接受等优点.远期疗效有待进一步观察.     

Sustained and localized in vitro release of BMP‐2/7, RANKL,and tetracycline from Flexbone,an elastomeric osteoconductive bone substitute

We tested the hypothesis that synthetic composites containing a high percentage of osteoconductive biominerals well‐integrated with a hydrophilic polymer matrix can be engineered to provide both the structural and biochemical framework of a viable synthetic bone substitute. FlexBone, an elastic hydrogel‐mineral composite exhibiting excellent structural integration was prepared by crosslinking poly(2‐hydroxyethyl methacrylate) hydrogel in the presence of 25 wt% nanocrystalline hydroxyapatite and 25 wt% tricalcium phosphate. Biologically active factors tetracycline, BMP‐2/7, and RANKL that stimulate bone formation and remodeling were encapsulated into FlexBone during polymerization or via postpolymerization adsorption. SEM and dynamic mechanical analyses showed that the encapsulation of tetracycline (5.0 wt%) did not compromise the structural integrity and compressive behavior of FlexBone, which could withstand repetitive megapascal‐compressive loadings and be securely press‐fitted into critical femoral defects. Dose‐dependent, sustained in vitro release of tetracycline was characterized by spectroscopy and bacterial inhibition. A single dose of 40 ng BMP‐2/7 or 10 ng RANKL pre‐encapsulated with 50 mg FlexBone, released over 1 week, was able to induce local osteogenic differentiation of myoblast C2C12 cells and osteoclastogenesis of macrophage RAW264.7 cells, respectively. With a bonelike structural composition, useful surgical handling characteristics, and tunable biochemical microenvironment, FlexBone provides an exciting opportunity for the treatment of hard‐to‐heal skeletal defects with minimal systemic side effects. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1306–1311, 2009     

膝关节周围骨巨细胞瘤的外科治疗

目的探讨膝关节周围骨巨细胞瘤的临床和影像学特点、手术方式的选择及临床疗效,讨论该病变可接受的外科治疗方式。方法 23例膝关节周围骨巨细胞瘤患者(股骨远端10例,胫骨近端12例,腓骨近端复发并胫骨转移1例)根据病变的临床、影像学特点选择不同手术方式:9例行瘤段切除肿瘤假体置换术;13例行肿瘤扩大刮除瘤腔灭活骨修复和内固定术(植骨9例,骨水泥填充4例),1例行截肢术。结果患者均获得随访,时间8~50个月。术后3例复发,肿瘤切除骨缺损修复组1例复发,肢体功能评分80%;肿瘤扩大刮除瘤腔灭活骨修复组2例复发,肢体功能评分95%。结论根据膝关节周围骨巨细胞瘤的临床及影像学特点选择合理的治疗方法,对肿瘤复发的控制及后续治疗方面具备一定的优势。     

颈椎骨巨细胞瘤手术治疗的中长期随访及预后分析

目的探讨颈椎骨巨细胞瘤（GCT）的临床特点、肿瘤切除方式及预后。方法手术治疗23例颈椎GCT,依据脊柱肿瘤WBB分期,采取椎体次全切除3例,矢状位切除5例,附件切除1例,全脊椎切除14例。脊柱重建方式采取单纯自体髂骨植骨和颈前路钛板、钛网植骨内固定或前后联合内固定加植骨融合。18例患者术后配合局部放疗。结果1例C1-2椎体、附件GCT患者在术后出现神经症状加重,术后10d因呼吸、循环系统衰竭死亡。22例获得3年～10年4个月的随访,患者术后颈部疼痛症状消失,神经根刺激症状得到不同程度的缓解,术后3个月患者神经功能Frankel分级,平均有1—2个级别的改善。植骨全部融合。内固定融合良好,未见脊椎失稳现象。椎体次全切除组复发3例;矢状位切除复发2例,而全脊椎切除组仅1例于术后4年复发。随访期内死亡4例,均为复发病例,1例行翻修手术后6个月出现肺部转移,13个月时死于肺部感染;另有3例均因肿瘤复发最终导致高位瘫痪、全身器官衰竭死亡。结论颈椎GCT是一种良性侵袭性或低度恶性肿瘤,手术治疗应在尽可能保留神经功能的前提下实施扩大范围的肿瘤切除术。全脊椎切除结合术后辅助放疗能明显降低局部复发率。     

Biomolecular basis of the role of diabetes mellitus in osteoporosis and bone fractures

Osteoporosis has become a serious health problem throughout the world which is associated with an increased risk of bone fractures and mortality among the people of middle to old ages. Diabetes is also a major health problem among the people of all age ranges and the sufferers due to this abnormality increasing day by day. The aim of this review is to summarize the possible mechanisms through which diabetes may induce osteoporosis. Diabetes mellitus generally exerts its effect on different parts of the body including bone cells specially the osteoblast and osteoclast, muscles, retina of the eyes, adipose tissue, endocrine system specially parathyroid hormone (PTH) and estrogen, cytokines, nervous system and digestive system. Diabetes negatively regulates osteoblast differentiation and function while positively regulates osteoclast differentiation and function through the regulation of different intermediate factors and thereby decreases bone formation while increases bone resorption. Some factors such as diabetic neuropathy, reactive oxygen species, Vitamin D, PTH have their effects on muscle cells. Diabetes decreases the muscle strength through regulating these factors in various ways and ultimately increases the risk of fall that may cause bone fractures.     

The effects of RANKL inhibition on fracture healing and bone strength in a mouse model of osteogenesis imperfecta

Currently, the standard treatment for osteogenesis imperfecta (OI) is bisphosphonate therapy. Recent studies, however, have shown delayed healing of osteotomies in a subset of OI patients treated with such agents. The current study sought to determine the effects of another therapy, RANKL inhibition, on bone healing and bone strength in the growing oim/oim mouse, a model of moderate to severe OI. Mice [73 oim/oim and 69 wild‐type (WT)] were injected twice weekly with either soluble murine RANK (RANK‐Fc) (1.5 mg/kg) or saline beginning at 6 weeks of age. At 8 weeks of age, the animals underwent transverse mid‐diaphyseal osteotomies of the right femur. Therapy was continued until sacrifice at 2, 3, 4, or 6 weeks postfracture. At 6 weeks post‐fracture, greater callus area (6.59 ± 3.78 mm² vs. 2.67 ± 2.05 mm², p = 0.003) and increased radiographic intensity (mineral density) (0.48 ± 0.14 vs. 0.30 ± 0.80, p = 0.005) were found in the RANK‐Fc versus saline oim/oim group, indicating a delay in callus remodeling. Despite this delay, mechanical tests at 6 weeks postfracture revealed no significant differences in whole bone properties of stiffness and failure moment. Further, RANKL inhibition resulted in a greater failure moment and greater work to failure for the nonfractured contralateral WT bones compared to the nonfractured saline WT bones. Together, these results demonstrate that RANKL inhibition does not adversely affect the mechanical properties of healing bone in the oim/oim mice, and is associated with increased strength in intact bone in the WT mice. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:153–164, 2008     

Prostate-specific antigen stimulates osteoprotegerin production and inhibits receptor activator of nuclear factor-kappaB ligand expression by human osteoblasts

BACKGROUND: Prostate cancer cells produce a large amount of prostate-specific antigen (PSA), which is widely used as a marker for this cancer. Even though it is widely used in the diagnosis of prostate cancer, many aspects of the pathophysiologic role of PSA in bone metastasis remain obscure. The receptor activator of nuclear factor-kappaB ligand (RANKL) is essential for the activation of osteoclasts, while osteoprotegerin (OPG) neutralizes the action of RANKL. Various substances that act on bone have been shown to modulate the production of RANKL and OPG by osteoblasts. METHODS: In this study, we investigated the effect of PSA on the expression of OPG and RANKL mRNA and on protein production in human osteoblast-like cells. RESULTS: After addition of PSA and culture for 72 h, OPG mRNA expression and protein secretion by MG-63 and SaOS-2 cells showed a concentration-dependent increase. When osteoblasts were incubated with PSA (100 ng/ml), OPG mRNA expression and protein secretion increased with the passage of time. alpha1 -antichymotrypsin (ACT), which inactivates the serine protease activity of PSA, inhibited the increase of OPG mRNA expression and protein production in response to PSA, and this effect of PSA was also inhibited by anti-transforming growth factor-beta antibody. CONCLUSIONS: Based on our findings, PSA acts on human osteoblast-like cells via its own serine protease activity and promotes osteoblast differentiation. In addition, PSA stimulates OPG production and inhibits RANKL expression of osteoblasts, and inhibits bone resorption by osteoclasts, suggesting that it contributes to the characteristic osteoblastic features of bone metastases of prostate cancer.     

Surgical results of the Lung Cancer Mutation Consortium 3 trial: A phase II multicenter single-arm study to investigate the efficacy and safety of atezolizumab as neoadjuvant therapy in patients with stages IB-select IIIB resectable non–small cell lung cancer

ObjectiveMultimodality treatment for resectable non–small cell lung cancer has long remained at a therapeutic plateau. Immune checkpoint inhibitors are highly effective in advanced non–small cell lung cancer and promising preoperatively in small clinical trials for resectable non–small cell lung cancer. This large multicenter trial tested the safety and efficacy of neoadjuvant atezolizumab and surgery.MethodsPatients with stage IB to select IIIB resectable non–small cell lung cancer and Eastern Cooperative Oncology Group performance status 0/1 were eligible. Patients received atezolizumab 1200 mg intravenously every 3 weeks for 2 cycles or less followed by resection. The primary end point was major pathological response in patients without EGFR/ALK+ alterations. Pre- and post-treatment computed tomography, positron emission tomography, pulmonary function tests, and biospecimens were obtained. Adverse events were recorded by Common Terminology Criteria for Adverse Events v.4.0.ResultsFrom April 2017 to February 2020, 181 patients were entered in the study. Baseline characteristics were mean age, 65.1 years; female, 93 of 181 (51%); nonsquamous histology, 112 of 181 (62%); and clinical stages IIB to IIIB, 147 of 181 (81%). In patients without EGFR/ALK alterations who underwent surgery, the major pathological response rate was 20% (29/143; 95% confidence interval, 14-28) and the pathological complete response rate was 6% (8/143; 95% confidence interval, 2-11). There were no grade 4/5 treatment-related adverse events preoperatively. Of 159 patients (87.8%) undergoing surgery, 145 (91%) had pathologic complete resection. There were 5 (3%) intraoperative complications, no intraoperative deaths, and 2 postoperative deaths within 90 days, 1 treatment related. Median disease-free and overall survival have not been reached.ConclusionsNeoadjuvant atezolizumab in resectable stage IB to IIIB non–small cell lung cancer was well tolerated, yielded a 20% major pathological response rate, and allowed safe, complete surgical resection. These results strongly support the further development of immune checkpoint inhibitors as preoperative therapy in locally advanced non–small cell lung cancer.