Human osteosarcoma is a genetically heterogeneous bone malignancy with poor prognosis despite the employment of aggressive chemotherapy regimens. Because druggable driver mutations have not been established, dissecting the interactions between osteosarcoma cells and supporting stroma may provide insights into novel therapeutic targets. By using a bioluminescent orthotopic xenograft mouse model of osteosarcoma, we evaluated the effect of tumor extracellular vesicle (EV)-educated mesenchymal stem cells (TEMSC) on osteosarcoma progression. Characterization and functional studies were designed to assess the mechanisms underlying MSC education. Independent series of tissue specimens were analyzed to corroborate the preclinical findings, and the composition of patient serum EVs was analyzed after isolation with size-exclusion chromatography. We show that EVs secreted by highly malignant osteosarcoma cells selectively incorporate a membrane-associated form of TGFβ, which induces proinflammatory IL6 production by MSCs. TEMSCs promote tumor growth, accompanied with intratumor STAT3 activation and lung metastasis formation, which was not observed with control MSCs. Importantly, intravenous administration of the anti-IL6 receptor antibody tocilizumab abrogated the tumor-promoting effects of TEMSCs. RNA-seq analysis of human osteosarcoma tissues revealed a distinct TGFβ-induced prometastatic gene signature. Tissue microarray immunostaining indicated active STAT3 signaling in human osteosarcoma, consistent with the observations in TEMSC-treated mice. Finally, we isolated pure populations of EVs from serum and demonstrated that circulating levels of EV-associated TGFβ are increased in osteosarcoma patients. Collectively, our findings suggest that TEMSCs promote osteosarcoma progression and provide the basis for testing IL6- and TGFβ-blocking agents as new therapeutic options for osteosarcoma patients. .
Surface-enhanced Raman spectroscopy (SERS) is a good candidate for the development of fast and easy-to-use diagnostic tools, possibly used on biofluids in point-of-care or screening tests. In particular, label-free SERS spectra of blood serum and plasma, two biofluids widely used in diagnostics, could be used as a metabolic fingerprinting approach for biomarker discovery. This study aims at a systematic evaluation of SERS spectra of blood serum and plasma, using various Ag and Au aqueous colloids, as SERS substrates, in combination with three excitation lasers of different wavelengths, ranging from the visible to the near-infrared. The analysis of the SERS spectra collected from 20 healthy subjects under a variety of experimental conditions revealed that intense and repeatable spectra are quickly obtained only if proteins are filtered out from samples, and an excitation in the near-infrared is used in combination with Ag colloids. Moreover, common plasma anticoagulants such as EDTA and citrate are found to interfere with SERS spectra; accordingly, filtered serum or heparin plasma are the samples of choice, having identical SERS spectra. Most bands observed in SERS spectra of these biofluids are assigned to uric acid, a metabolite whose blood concentration depends on factors such as sex, age, therapeutic treatments, and various pathological conditions, suggesting that, even when the right experimental conditions are chosen, great care must be taken in designing studies with the purpose of developing diagnostic tests.
Background-Excessive bleeding may complicate congenital cardiac defects. To explain the pathogenesis of this abnormality, we evaluated selected parameters of primary hemostasis in patients with aortic valve stenosis before and after corrective surgery. Methods and Results-We examined shear-induced platelet aggregation with the filter aggregometer test and von Willebrand factor (vWF) structure by evaluating the multimeric distribution and extent of subunit proteolysis. The platelet count was reduced before corrective surgery, and shear-induced platelet aggregation was impaired. Moreover, vWF multimers of higher molecular mass were decreased, and proteolytic subunit fragments were increased. After correction of the cardiac defect, all of these parameters returned to normal. Conclusions-Alterations of vWF and platelet function may contribute to the bleeding diathesis in patients with aortic valve stenosis. Improvement after corrective surgery suggests that the passage of blood through a stenosed aortic valve may result in shear forces that induce vWF interaction with platelets in the circulation and, in turn, trigger platelet clearance, vWF degradation, and the impairment of primary hemostasis.
Summary Cases of B‐cell chronic lymphocytic leukaemia (B‐CLL) with mutated (M) IgVH genes have a better prognosis than unmutated (UM) cases. We analysed the IgVH mutational status of B‐CLL according to the features of a canonical somatic hypermutation (SHM) process, correlating this data with survival. In a series of 141 B‐CLLs, 124 cases were examined for IgVH gene per cent mutations and skewing of replacement/silent mutations in the framework/complementarity‐determining regions as evidence of antigen‐driven selection; this identified three B‐CLL subsets: significantly mutated (sM), with evidence of antigen‐driven selection, not significantly mutated (nsM) and UM, without such evidence and IgVH gene per cent mutations above or below the 2% cut‐off. sM B‐CLL patients had longer survival within the good prognosis subgroup that had more than 2% mutations of IgVH genes. sM, nsM and UM B‐CLL were also characterized for the biased usage of IgVH families, intraclonal IgVH gene diversification, preference of mutations to target‐specific nucleotides or hotspots, and for the expression of enzymes involved in SHM (translesion DNA polymerase ζ and η and activation‐induced cytidine deaminase). These findings indicate the activation of a canonical SHM process in nsM and sM B‐CLLs and underscore the role of the antigen in defining the specific clinical and biological features of B‐CLL.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.