Angiosarcoma is a rare and generally fatal tumor composed of aberrant cells of endothelial origin.Because of its infrequency in humans, very little is known about the growth requirements of this vascular sarcoma.Unlike the rapidly proliferating solid tumors from which they are isolated from, many of the established angiosarcoma cell lines exhibit less than robust growth in culture and often fail to form tumors in xenograft models.In order to better understand angiosarcoma in vitro growth conditions, we focused on a singular aspect of their culture-adhesion to the extracellular matrix-in order to identify attachment substrates that may facilitate and/or enhance their growth in tissue culture.Our data indicates that the extracellular matrix of angiosarcomas contains similar protein compositions to that of non-diseased endothelial cells.Moreover, angiosarcoma cell lines exhibited strong attachment preference to substrates such as collagen I or fibronectin, and less preference to collagen IV, laminin, or tropoelastin.Growth on preferred extracellular matrix substrates promoted mitogenic signaling and increased proliferation of angiosarcoma cell lines.These findings provide insight that may lead to more successful in vitro growth of angiosarcoma cell lines.
Analysis of global protein phosphorylation in ROCK1 and 2 knockdown SVR cells. A high throughput antibody array composed of 1358 antibodies covering more than 20 central signaling pathways was performed on lysates collected from ROCK1 and 2 shRNA SVR cells and a corresponding scrambled shRNA control. The data is presented as the normalized median signal values of each antibody spot. Moreover, the fold expression change was compared between ROCK shRNA and scrambled shRNA control SVR cells. (XLS 241Â kb)
Epithelial cell adhesion molecule (EpCAM) is a protein involved in cell-to-cell attachment and is considered to be strictly expressed in epithelial tissues and epithelial-derived tumors. Furthermore, EpCAM has been shown to be a negative prognostic marker for several carcinomas. In this study, we performed a genomic meta-analysis of gene expression profiles housed in the Cancer Cell Line Encyclopedia to demonstrate that EpCAM mRNA is expressed at low to moderate levels in certain sarcoma cell lines. We utilized immunohistochemical staining to confirm that the EpCAM protein is expressed in a subset of angiosarcomas and leiomyosarcomas and in all the investigated osteosarcomas. Finally, we conducted a statistical analysis of clinical data to demonstrate that EpCAM protein expression is significantly and directly correlated with the degree of cytological atypia in leiomyosarcomas. In conclusion, this data suggests that, contrary to conventional beliefs, EpCAM is expressed in a subset of sarcomas and is a negative prognostic marker for leiomyosarcomas.
Abstract Osteosarcoma, the most common primary bone tumor in humans and dogs, has a guarded prognosis. A major hurdle in developing more effective osteosarcoma therapies is the lack of disease-specific biomarkers to predict risk, prognosis, or therapeutic response. Exosomes are secreted extracellular microvesicles emerging as powerful diagnostic tools. However, the wide clinical use of exosomes is precluded by the challenges in identifying disease-associated cargo from the vastly larger background of normal exosome cargo. We developed a method using canine osteosarcoma xenografts to distinguish tumor-derived exosome mRNAs and host-response mRNAs, allowing for identification of osteosarcoma-specific gene signatures, which were then validated in samples from dogs with osteosarcoma. A canine osteosarcoma-associated gene signature was developed using exosomes from mouse xenograft experiments and a species-aware bioinformatics pipeline. Validation of the gene signature in canine serum exosomes was done by qRT-PCR analysis. Machine learning algorithms assigned dogs into healthy or disease groups based on the qRT-PCR data. Dogs in a validation set of clinical osteosarcoma cases with post-treatment samples were classified as “osteosarcoma -detected” or “osteosarcoma - NOT detected”, and clinical outcome measures were compared. An osteosarcoma-associated signature consisting of five mRNAs (SKA2, NEU1, PAF1, PSMG2, and NOB1) was identified using our canine osteosarcoma xenograft model. Serum exosomes were isolated from 53 dogs in distinct clinical groups, including “healthy”, “osteosarcoma”, “other bone tumor”, or “non-neoplastic disease”. Dogs in a validation set whose post-treatment samples were classified as “osteosarcoma - NOT detected” had longer remissions than dogs classified as “osteosarcoma - detected” for up to 15 months after treatment. In conclusion, we identified a gene signature associated with canine osteosarcoma for the detection of minimal residual disease. This gene signature was validated by qRT-PCR with serum exosomes from canine patients with osteosarcoma, and used to train artificial intelligence. The test results were predictive of molecular remissions in dogs up to 15 months after initiating therapy, suggesting it will have applications in the early detection and minimal residual disease settings. This study combines a bioinformatics approach to biomarker discovery with machine learning to correctly identify osteosarcoma in canine patients. These results set the stage for future discoveries to inform cancer risk, diagnosis, prognosis, and response to therapy. Citation Format: Kelly M. Makielski, Alicia J. Donnelly, Ali Khammanivong, Milcah C. Scott, Hirotaka Tomiyasu, John Garbe, Lauren J. Mills, Gary R. Cutter, Andrea Ortiz, Dana C. Galvan, Kristi Ward, Alexa N. Montoya, Brad A. Bryan, Joelle M. Fenger, William C. Kisseberth, Subbaya Subramanian, Jaime F. Modiano. Development of an exosomal biomarker signature to detect minimal residual disease in dogs with osteosarcoma using a novel xenograft platform and machine learning [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 671.
The modification (or abrogation) of the hyperacute rejection (HAR) process has been one of the major areas of study by xenotransplantation researchers since work began in this area in the 1960s. Manipulations of blood cellular and humoral components as well as the use of pharmacologic agents have all been studied extensively in the past.
