Calcitonin Gene-Related Peptide Inhibits Osteolytic Factors Induced by Osteoblast In Co-Culture System with Breast Cancer

Novel calcitonin gene-related peptide/chitosan-strontium-calcium phosphate cement: Enhanced proliferation of human umbilical vein endothelial cells in vitro

Bone cement materials have some disadvantages, including slow degradation and no biological activity, which greatly weakens their clinical application. Therefore, the search for a multifunctional bioactive bone cement has become urgent. In this study, a novel bone cement sample of calcitonin gene-related peptide (CGRP)/chitosan-strontium (Sr)-calcium phosphate cement (CPC) was developed. The structure and morphology were observed by scanning electron microscope (SEM). The cytotoxicity and proliferation of CGRP/chitosan-Sr-CPC were also measured. The expression of CGRP receptor 1 was measured using an immunofluorescence assay. Real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) were employed to quantify the VEGF mRNA and protein levels, respectively. Finally, the ability of the material to improve angiogenesis was assessed by using human umbilical vein endothelial cells (HUVECs) tube formation assay. The results showed that CGRP/Chitosan-Sr-CPC had the characteristics of a good orthopedic material without showing cell cytotoxicity to HUVECs. Meanwhile, CGRP/chitosan-Sr-CPC could release CGRP and enhance the proliferation of HUVECs via CGRP receptors. Moreover, CGRP/chitosan-Sr-CPC significantly upregulated the expression of the VEGF gene and protein in HUVECs, which might help improve the angiogenesis microenvironment. Besides, CGRP/chitosan-Sr-CPC could significantly improve angiogenesis of HUVECs. These findings provide new therapeutic material for the treatment of osteoporotic bone injury. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 19-28, 2019.

A single intraperitoneal injection of bovine fetuin-A attenuates bone resorption in a murine calvarial model of particle-induced osteolysis

Particle-induced osteolysis, which by definition is an aseptic inflammatory reaction to implant-derived wear debris eventually leading to local bone destruction, remains the major reason for long-term failure of orthopedic endoprostheses. Fetuin-A, a 66kDa glycoprotein with diverse functions, is found to be enriched in bone. Besides being an important inhibitor of ectopic calcification, it has been described to influence the production of mediators of inflammation. Furthermore, a regulatory role in bone metabolism has been assigned. In the present study, the influence of a single dose of bovine fetuin-A, intraperitoneally injected in mice subjected to particle-induced osteolysis of the calvaria, was analyzed. Twenty-eight male C57BL/6 mice, twelve weeks of age, were randomly divided into four groups. Groups 2 and 4 were subjected to ultra-high molecular weight polyethylene (UHMWPE) particles placed on their calvariae while groups 1 and 3 were sham-operated. Furthermore, groups 3 and 4 received a single intraperitoneal injection of 20mg bovine fetuin-A while groups 1 and 2 were treated with physiologic saline. After 14days calvarial bone was qualitatively and quantitatively assessed using microcomputed tomography (μCT) and histomorphometrical approaches. Application of fetuin-A led to a reduction of particle-induced osteolysis in terms of visible osteolytic lesions and eroded bone surface. The reduction of bone thickness and bone volume, as elicited by UHMWPE, was alleviated by fetuin-A. In conclusion, fetuin-A was found to exert an anti-resorptive effect on particle-induced osteolysis in-vivo. Thus, fetuin-A could play a potentially osteoprotective role in the treatment of bone metabolic disorders.

The genomic dynamics during progression of lung adenocarcinomas

Intra-tumor heterogeneity is a big barrier to precision medicine. To explore the underlying clonal diversity in lung adenocarcinomas, we selected nine individuals with whole-genome sequencing data from primary and matched metastatic tumors as a cohort for study. Similar global pattern of arm-level copy number changes and large variations of somatic single-nucleotide variant between the primary and metastasis are observed in the majority of cases. Importantly, we found breakage-fusion-bridge (BFB) cycles acting as an important mechanism for underlying cancer gene amplification, such as amplification of CDK4, CDKN3 and FGFR1 in early stage. We also identified recurrent focal amplification of gene CCNY derived from BFB in two metastatic tumors, but not in primary tumor. Clonal analysis of case 236T demonstrated that mutational processes are varying with tumor progression. Collectively, our data provide new insights into genetic diversity and potential therapeutic target in lung adenocarcinoma.

In Vitro Co-Culture Models of Breast Cancer Metastatic Progression towards Bone

Advanced breast cancer frequently metastasizes to bone through a multistep process involving the detachment of cells from the primary tumor, their intravasation into the bloodstream, adhesion to the endothelium and extravasation into the bone, culminating with the establishment of a vicious cycle causing extensive bone lysis. In recent years, the crosstalk between tumor cells and secondary organs microenvironment is gaining much attention, being indicated as a crucial aspect in all metastatic steps. To investigate the complex interrelation between the tumor and the microenvironment, both in vitro and in vivo models have been exploited. In vitro models have some advantages over in vivo, mainly the possibility to thoroughly dissect in controlled conditions and with only human cells the cellular and molecular mechanisms underlying the metastatic progression. In this article we will review the main results deriving from in vitro co-culture models, describing mechanisms activated in the crosstalk between breast cancer and bone cells which drive the different metastatic steps.

OPG-Fc inhibits ovariectomy-induced growth of disseminated breast cancer cells in bone

Dormant disseminated tumour cells can be detected in the bone marrow of breast cancer patients several years after resection of the primary tumour. The majority of these patients will remain asymptomatic, however, ∼ 15% will go on to develop overt bone metastases and this condition is currently incurable. The reason why these dormant cells are stimulated to proliferate and form bone tumours in some patients and not others remains to be elucidated. We have recently shown that in an in vivo model, increasing bone turnover by ovariectomy stimulated proliferation of disseminated tumour cells, resulting in formation of bone metastasis. We now show for the first time that osteoclast mediated mechanisms induce growth of tumours from dormant MDA-MB-231 cells disseminated in the bone. We also show that disruption of RANK-RANKL interactions following administration of OPG-Fc inhibits growth of these dormant tumour cells in vivo. Our data support early intervention with anti-resorptive therapy in a low-oestrogen environment to prevent development of bone metastases.