Major basement membrane components in Kaposi's sarcoma, angiosarcoma and benign vascular neogenesis

Hemangiosarcoma in dogs as a potential non-rodent animal model for drug discovery research of angiosarcoma in humans

Since the domestication of dogs 10,000 years ago, they have shared their living environment with humans and have co-evolved. The breeding process that dogs have undergone in only a few centuries has led to a significant accumulation of specific genetic alterations that could induce particular diseases in certain breeds. These canine diseases are similar to what is found in humans with several differences; therefore, comparing such diseases occurring in humans and dogs can help discover novel disease mechanisms, pathways, and causal genetic factors. Human angiosarcoma (AS) and canine hemangiosarcoma (HSA), which are sarcomas originating from endothelium, are examples of diseases shared between humans and dogs. They exhibit similar characteristics and clinical behaviors, although with some critical differences resulting from evolution. In this review, we will describe the similarities and differences in terms of clinical and molecular characteristics between human AS and canine HSA, and discuss how these similarities and differences can be applied to advance the treatment of these diseases.

Extracellular matrix composition modulates angiosarcoma cell attachment and proliferation

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.

Angiosarcoma

Angiosarcomas are rare soft-tissue sarcomas of endothelial cell origin that have a poor prognosis. They can arise anywhere in the body, most commonly presenting as cutaneous disease in elderly white men, involving the head and neck and particularly the scalp. They can be caused by therapeutic radiation or chronic lymphoedema and hence secondary breast angiosarcomas are an important subgroup. Recent work has sought to establish the molecular biology of angiosarcomas and identify specific targets for treatment. Interest is now focused on trials of vascular-targeted drugs, which are showing promise in the control of angiosarcomas. In this review we discuss angiosarcoma and its current management, with a focus on clinical trials investigating the treatment of advanced disease.