Navegando por Palavras-chave "c-kit"

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    C-kit expression in human osteosarcoma and in vitro assays
    (E-century Publishing Corp, 2011-01-01) Miiji, Luciana Nakao Odashiro [UNIFESP]; Petrilli, Antonio Sergio [UNIFESP]; Di Cesare, Sebastian; Odashiro, Alexandre Nakao [UNIFESP]; Burnier, Miguel Noel Nascente [UNIFESP]; Toledo, Silvia Regina Caminada de [UNIFESP]; Garcia, Reynaldo Jesus; Alves, Maria Teresa de Seixas [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); McGill Univ; Ctr Hosp Afillie Univ Quebec
    Biologic agents targeting oncogenes have encourage researchs trying to correlate the role of tyrosine kinase in the pathogenesis of tumours. Osteosarcoma is a high grade aggressive neoplasm with poor survival. Our aim was to investigate c-kit immunoexpression, its prognostic relevance for patients with osteosarcoma, and the effect of imatinib mesylate (STI571) on proliferation and invasion of the human osteosarcoma cell line. A retrospective immunohistochemical study was performed on archival formalin-fixed paraffin-embedded specimens from 52 patients with high-grade primary osteosarcoma of extremities treated at the Pediatric Oncology Institute (IOP, GRAAC) and archived in the Department of Pathology, Federal University of Sao Paulo. Only pre-chemotherapy specimens were analyzed. Strongly stained cytoplasm and membrane cells were taken as positive. Human osteosarcoma cells from line MG-63 were incubated and the inhibitory effect of imatinib mesylate (STI571) on cell proliferation and invasion was studied. In 24 cases (46.15%), c-kit was expressed by the cells and c-kit-positive tumors exhibited lower necrosis post-chemotherapy. No correlation was found between c-kit expression and overall and disease-free survival. Imatinib mesylate decreased the rates of cell growth of osteosarcoma cells in low doses and invasion in high doses C-kit-positive tumors had worse response to chemotherapy and imatinib mesylate can play a role in blocking or decreasing the rate of growth of osteosarcoma cells, but not the invasive capacity of these neoplastic cells. These data suggested that imatinib mesylate could be a therapeutic target of strategies against osteosarcoma tumors. Further studies are necessary to confirm this indication.
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    The effect of imatinib mesylate on the proliferation, invasive ability, and radiosensitivity of retinoblastoma cell lines
    (Nature Publishing Group, 2013-01-01) Moura, L. R. de; Marshall, J-C; Di Cesare, S.; Fernandes, B. F.; Antecka, E.; Burnier, M. N.; McGill Univ; Henry C Witelson Ocular Pathol Lab; Inst Brasileiro Oftalmol; Universidade Federal de São Paulo (UNIFESP)
    Purpose Our aim was to evaluate the potential effect of imatinib mesylate (IM), a small molecule that specifically inhibits the tyrosine quinase receptors, on the proliferation and invasive abilities of two human retinoblastoma (Rb) cell lines. Furthermore, the ability of IM to radiosensitize Rb cells was evaluated. the potential targets of IM (C-kit, PDGRF-alpha and -beta, and c-Abl) were also investigated in these cell lines.Methods Two human Rb cell lines (WERI-RB-1 and Y79) were cultured under normal growth conditions. An MTT-based proliferation assay and a Matrigel invasion assay were performed with and without exposure to 10 mu M of IM. the cells were also irradiated with graded dosages of 0, 2, 4, 6, 8, and 10 Gy with and without IM and their proliferations rates were analyzed. Western blot and immunocytochemical analysis of cytospins were performed to evaluate the expression of C-kit, PDGRF-alpha and -beta, and c-Abl.Results When IM was added to both cell lines a statistically significant (P<0.05) reduction in proliferation and invasive ability were observed. Exposure to IM also significantly increased the radiosensitivity of both Rb cell lines. the c-Abl expression was strongly positive, PDGRF-alpha and -beta expression were also positive but the C-kit expression was negative in both cell lines.Conclusions These results indicate that Gleevec may be useful as an adjuvant treatment in Rb patients, specially those considered for radiation therapy. Eye (2013) 27, 92-99; doi:10.1038/eye.2012.231; published online 16 November 2012
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    Immunohistochemical expression of COX-2 and c-kit in metastatic uveal melanoma
    (Canadian Ophthal Soc, 2007-02-01) Frota, Ana C. A.; Odashiro, Alexandre N.; Pereira, Patricia R.; Fernandes, Bruno F.; Godeiro, Katyanne Dantas; Souza Filho, Joao Pessoa; Burnier, Miguel N.; Universidade Federal de São Paulo (UNIFESP); McGill Univ
    Case report: We report a case of choroidal melanoma metastatic to the liver diagnosed by fine-needle aspiration. the biopsy sample was immunostained for COX-2 and c-kit.Comments: Accurate diagnosis and identification of potential therapeutic targets are important for subsequent therapy and can be achieved by radiologically guided fine-needle aspiration biopsy.