Altering adsorbed proteins or cellular gene expression in bone-metastatic cancer cells affects PTHrP and Gli2 without altering cell growth

AbstractThe contents of this data in brief are related to the article titled “Matrix Rigidity Regulates the Transition of Tumor Cells to a Bone-Destructive Phenotype through Integrin β3 and TGF-β Receptor Type II”. In this DIB we will present our supplemental data investigating Integrin expression, attachment of cells to various adhesion molecules, and changes in gene expression in multiple cancer cell lines. Since the interactions of Integrins with adsorbed matrix proteins are thought to affect the ability of cancer cells to interact with their underlying substrates, we examined the expression of Integrin β1, β3, and β5 in response to matrix rigidity. We found that only Iβ3 increased with increasing substrate modulus. While it was shown that fibronectin greatly affects the expression of tumor-produced factors associated with bone destruction (parathyroid hormone-related protein, PTHrP, and Gli2), poly-l-lysine, vitronectin and type I collagen were also analyzed as potential matrix proteins. Each of the proteins was independently adsorbed on both rigid and compliant polyurethane films which were subsequently used to culture cancer cells. Poly-l-lysine, vitronectin and type I collagen all had negligible effects on PTHrP or Gli2 expression, but fibronectin was shown to have a dose dependent effect. Finally, altering the expression of Iβ3 demonstrated that it is required for tumor cells to respond to the rigidity of the matrix, but does not affect other cell growth or viability. Together these data support the data presented in our manuscript to show that the rigidity of bone drives Integrinβ3/TGF-β crosstalk, leading to increased expression of Gli2 and PTHrP

Matrix Rigidity Induces Osteolytic Gene Expression of Metastatic Breast Cancer Cells

Nearly 70% of breast cancer patients with advanced disease will develop bone metastases. Once established in bone, tumor cells produce factors that cause changes in normal bone remodeling, such as parathyroid hormone-related protein (PTHrP). While enhanced expression of PTHrP is known to stimulate osteoclasts to resorb bone, the environmental factors driving tumor cells to express PTHrP in the early stages of development of metastatic bone disease are unknown. In this study, we have shown that tumor cells known to metastasize to bone respond to 2D substrates with rigidities comparable to that of the bone microenvironment by increasing expression and production of PTHrP. The cellular response is regulated by Rho-dependent actomyosin contractility mediated by TGF-ß signaling. Inhibition of Rho-associated kinase (ROCK) using both pharmacological and genetic approaches decreased PTHrP expression. Furthermore, cells expressing a dominant negative form of the TGF-ß receptor did not respond to substrate rigidity, and inhibition of ROCK decreased PTHrP expression induced by exogenous TGF-ß. These observations suggest a role for the differential rigidity of the mineralized bone microenvironment in early stages of tumor-induced osteolysis, which is especially important in metastatic cancer since many cancers (such as those of the breast and lung) preferentially metastasize to bone

Nonthrombogenic, Biodegradable Elastomeric Polyurethanes with Variable Sulfobetaine Content

For applications where degradable polymers are likely to have extended blood contact, it is often important for these materials to exhibit high levels of thromboresistance. This can be achieved with surface modification approaches, but such modifications may be transient with degradation. Alternatively, polymer design can be altered such that the bulk polymer is thromboresistant and this is maintained with degradation. Toward this end a series of biodegradable, elastic polyurethanes (PESBUUs) containing different zwitterionic sulfobetaine (SB) content were synthesized from a polycaprolactone-diol (PCL-diol):SB-diol mixture (100:0, 75:25, 50:50, 25:75 and 0:100) reacted with diisocyanatobutane and chain extended with putrescine. The chemical structure, tensile mechanical properties, thermal properties, hydrophilicity, biodegradability, fibrinogen adsorption and thrombogenicity of the resulting polymers was characterized. With increased SB content some weakening in tensile properties occurred in wet conditions and enzymatic degradation also decreased. However, at higher zwitterionic molar ratios (50% and 75%) wet tensile strength exceeded 15 MPa and breaking strain was >500%. Markedly reduced thrombotic deposition was observed both before and after substantial degradation for both of these PESBUUs and they could be processed by electrospinning into a vascular conduit format with appropriate compliance properties. The mechanical and degradation properties as well as the acute in vitro thrombogenicity assessment suggest that these tunable polyurethanes could provide options appropriate for use in blood contacting applications where a degradable, elastomeric component with enduring thromboresistance is desired

Bone morphogenetic proteins − 7 and − 2 in the treatment of delayed osseous union secondary to bacterial osteitis in a rat model

Background: Bone infections due to trauma and subsequent delayed or impaired fracture healing represent a great challenge in orthopedics and trauma surgery. The prevalence of such bacterial infection-related types of delayed non-union is high in complex fractures, particularly in open fractures with additional extensive soft-tissue damage. The aim of this study was to establish a rat model of delayed osseous union secondary to bacterial osteitis and investigate the impact of rhBMP-7 and rhBMP-2 on fracture healing in the situation of an ongoing infection. Methods: After randomization to four groups 72 Sprague-Dawley rats underwent a transverse fracture of the midshaft tibia stabilized by intramedullary titanium K-wires. Three groups received an intramedullary inoculation with Staphylococcus aureus (103 colony-forming units) before stabilization and the group without bacteria inoculation served as healing control. After 5 weeks, a second surgery was performed with irrigation of the medullary canal and local rhBMP-7 and rhBMP-2 treatment whereas control group and infected control group received sterile saline. After further 5 weeks rats were sacrificed and underwent biomechanical testing to assess the mechanical stability of the fractured bone. Additional micro-CT analysis, histological, and histomorphometric analysis were done to evaluate bone consolidation or delayed union, respectively, and to quantify callus formation and the mineralized area of the callus. Results: Biomechanical testing showed a significantly higher fracture torque in the non-infected control group and the infected rhBMP-7- and rhBMP-2 group compared with the infected control group (p < 0.001). RhBMP-7 and rhBMP-2 groups did not show statistically significant differences (p = 0.57). Histological findings supported improved bone-healing after rhBMP treatment but quantitative micro-CT and histomorphometric results still showed significantly more hypertrophic callus tissue in all three infected groups compared to the non-infected group. Results from a semiquantitative bone-healing-score revealed best bone-healing in the non-infected control group. The expected chronic infection was confirmed in all infected groups. Conclusions: In delayed bone healing secondary to infection rhBMP treatment promotes bone healing with no significant differences in the healing efficacy of rhBMP-2 and rhBMP-7 being noted. Further new therapeutic bone substitutes should be analyzed with the present rat model for delayed osseous union secondary to bacterial osteitis

Designing Bioactive Delivery Systems for Tissue Regeneration

The direct infusion of macromolecules into defect sites generally does not impart adequate physiological responses. Without the protection of delivery systems, inductive molecules may likely redistribute away from their desired locale and are vulnerable to degradation. In order to achieve efficacy, large doses supplied at interval time periods are necessary, often at great expense and ensuing detrimental side effects. The selection of a delivery system plays an important role in the rate of re-growth and functionality of regenerating tissue: not only do the release kinetics of inductive molecules and their consequent bioactivities need to be considered, but also how the delivery system interacts and integrates with its surrounding host environment. In the current review, we describe the means of release of macromolecules from hydrogels, polymeric microspheres, and porous scaffolds along with the selection and utilization of bioactive delivery systems in a variety of tissue-engineering strategies

Catheter-Related Venous Thrombosis in Hospitalized Pediatric Patients with Inflammatory Bowel Disease: Incidence, Characteristics, and Role of Anticoagulant Thromboprophylaxis with Enoxaparin

© 2018 Elsevier Inc. Objective: To describe the incidence and characteristics of central venous catheter (CVC)-related thrombosis in hospitalized pediatric patients with active inflammatory bowel disease (IBD) and report the potential usefulness of anticoagulant thromboprophylaxis (AT). Study design: We conducted a retrospective study of patients who were admitted to our children\u27s hospital in the last 2 years with active IBD and required a CVC and identified all patients with an objectively confirmed symptomatic CVC-related thrombosis. To assess the usefulness of a recently implemented institutional AT protocol, we compared the frequency of CVC-related thrombosis, nadir hemoglobin, and red blood cell transfusion requirements in patients who received AT with those who did not during the study period. Results: A total of 40 patients with IBD who required 47 consecutive hospitalizations were included. AT was administered during 24 of 47 hospitalizations (51%). Patients who received AT were similar to those who did not receive AT with regard to demographics, IBD phenotypes, extent of colonic involvement, and thrombotic risk factors. CVC-related thrombosis occurred in 5 of 23 hospitalizations (22%) in which AT was withheld compared with 0 of 24 hospitalizations (0%) in which patients received AT (P =.02). The red blood cell transfusion requirements and nadir hemoglobin were not significantly different between the 2 groups. Conclusions: We observed a high incidence of CVC-related thrombosis in hospitalized children with IBD. Administration of AT in our population was associated with significant reduction in CVC-related thrombosis without evidence of increased bleeding