Expression and significance of secreted protein acidic and rich in cysteine in human osteosarcoma

The role of SPARC/ON in human osteosarcoma

The human osteosarcoma is a malignant tumor of the arthro-skeletal system. It has been recognized that it is the most common malignancy followed by the Ewing sarcoma or primitive neuroectodermal tumor. The prognosis is worrisome and is not preserved by the use of classical chemotherapy drugs. High rates of recurrence and metastases often accompany this malignant tumor. Chemotherapy often fails because of the onset of multidrug resistance, even though the mechanism to reach chemotherapy resistance is still intriguing and contains unclear pathways. The secreted protein acidic and rich in cysteine (SPARC) or osteonectin (ON) (SPARC/ON) has been associated with poor prognosis in several malignant neoplasms. In this mini-review, we are going to highlight the role of SPARC/ON in human osteosarcoma. Extracellular vesicles are fundamental in cell-to-cell communication. We suggest that a liquid biopsy targeting SPARC/ON may be critical to implement in the surveillance of patients with this malignant bony neoplasm.

Role of αVβ3 in Prostate Cancer: Metastasis Initiator and Important Therapeutic Target

In prostate cancer, distant organ metastasis is the leading cause of patient death. Although the mechanism of malignant tumor metastasis is unclear, studies have confirmed that integrin αVβ3 plays an important role in this process. In prostate cancer, αVβ3 mediates adhesion, invasion, immune escape and neovascularization through interactions with different ligands. Among these ligands and in addition to proteins that are directly related to tumor invasion, other proteins that contain the RGD structure could also bind to αVβ3 and cause a number of biological effects. In this article, we summarized the ligand and downstream proteins related to αVβ3-mediated prostate cancer metastasis as well as some diagnostic and therapeutic measures targeting αVβ3.

Vimentin, osteocalcin and osteonectin expression in canine primary bone tumors: diagnostic and prognostic implications

Canine primary bone tumors have a plastic radiographic image, demanding histopathological confirmation. Bone tumors are characterized by the type and amount of extracellular matrix produced what cannot be easily recognized, especially in biopsy samples. Identifying cellular markers that could aid diagnosis has supported various studies in oncological pathology. This study aimed to evaluate 22 canine primary bone neoplasms, establishing their histopathological diagnosis and evaluated vimentin, osteonectin and osteocalcin expression and their implication in diagnosis and prognosis. There were 12 productive osteoblastic osteosarcomas, six minimally productive osteoblastic osteosarcoma, two chondrosarcomas, one fibrosarcoma and one hemangiosarcoma. Immunostaining was cytoplasmatic in all cases, with average percentage of 87.9% for vimentin, 98.0% for osteonectin and 99.9% for osteocalcin. In this last case, only osteosarcomas were considered. Intensity was higher in vimentin labeling (+++), followed by osteonectin (++) and osteocalcin (+). One osteosarcoma showed negative immunostaining for vimentin and of samples submitted to anti-osteocalcin immunostaining, three osteosarcomas and one fibrosarcoma had negative staining. Besides identifying mesenchymal origin, vimentin elevated expression in canine bone tumors can be related to epithelial-mesenchymal transition, leading to more aggressive tumoral phenotypes and metastasis development. Similarly, high osteonectin expression is implicated in neoplastic cell invasion and is also related to metastasis spread. Decreased osteocalcin expression was found in some osteosarcoma samples and can be related to poor prognosis, as in human osteosarcomas. Our findings suggest that vimentin, osteonectin and osteocalcin not only aid diagnosis but can be related to prognosis in canine primary bone tumors, especially osteosarcomas and its osteoblastic subtype.