CHRISTIAN ALBERT MERKEL
Projetos de Pesquisa
Unidades Organizacionais
SVMULTI-05, Faculdade de Medicina
2 resultados
Resultados de Busca
Agora exibindo 1 - 2 de 2
- Combined p19Arf and interferon-beta gene transfer enhances cell death of B16 melanoma in vitro and in vivo(2013) MERKEL, C. A.; MEDRANO, R. F. V.; BARAUNA, V. G.; STRAUSS, B. E.Approximately 90% of melanomas retain wild-type p53, a characteristic that may help shape the development of novel treatment strategies. Here, we employed an adenoviral vector where transgene expression is,controlled by p53 to deliver the p19 alternate reading frame (An) and interferon-beta (IFN beta) complementary DNAs in the B16 mouse model of melanoma. In vitro, cell death was enhanced by combined gene transfer (63.82 +/- 15.30% sub-GO cells); yet introduction of a single gene resulted in significantly fewer hypoploid cells (37.73 +/- 7.3% or 36.96 +/- 11.58%, p19Arf or IFN beta, respectively, P < 0.05). Annexin V staining and caspase-3 cleavage indicate a cell death mechanism consistent with apoptosis. Using reverse transcriptase quantitative PCR, we show that key transcriptional targets of p53 were upregulated in the presence of p19Arf, although treatment with IFN beta did not alter expression of the genes studied. In situ gene therapy revealed significant inhibition of subcutaneous tumors by IFN beta (571 +/- 25 mm(3)) or the combination of p19Arf and IFN beta (489 +/- 124 mm(3)) as compared with the LacZ control (1875 +/- 33 mm(3), P < 0.001); whereas p19Arf yielded an intermediate result (1053 +/- 169 mm(3), P < 0.01 vs control). However, only the combination was associated with increased cell death and prolonged survival (P < 0.01). As shown here, the combined transfer of p19Arf and IFN beta using p53-responsive vectors enhanced cell death both in vitro and in vivo.
- Vaccination using melanoma cells treated with p19arf and interferon beta gene transfer in a mouse model: a novel combination for cancer immunotherapy(2016) MEDRANO, Ruan Felipe Vieira; CATANI, Joao Paulo Portela; RIBEIRO, Aline Hunger; TOMAZ, Samanta Lopes; MERKEL, Christian A.; COSTANZI-STRAUSS, Eugenia; STRAUSS, Bryan E.Previously, we combined p19(Arf) (Cdkn2a, tumor suppressor protein) and interferon beta (IFN-beta, immunomodulatory cytokine) gene transfer in order to enhance cell death in a murine model of melanoma. Here, we present evidence of the immune response induced when B16 cells succumbing to death due to treatment with p19(Arf) and IFN-beta are applied in vaccine models. Use of dying cells for prophylactic vaccination was investigated, identifying conditions for tumor-free survival. After combined p19(Arf) and IFN-beta treatment, we observed immune rejection at the vaccine site in immune competent and nude mice with normal NK activity, but not in NOD-SCID and dexamethasone immunosuppressed mice (NK deficient). Combined treatment induced IL-15, ULBP1, FAS/APO1 and KILLER/DR5 expression, providing a mechanism for NK activation. Prophylactic vaccination protected against tumor challenge, where markedly delayed progression and leukocyte infiltration were observed. Analysis of primed lymphocytes revealed secretion of TH1-related cytokines and depletion protocols showed that both CD4(+) and CD8(+) T lymphocytes are necessary for immune protection. However, application of this prophylactic vaccine where cells were treated either with IFN-beta alone or combined with p19(Arf) conferred similar immune protection and cytokine activation, yet only the combination was associated with increased overall survival. In a therapeutic vaccine protocol, only the combination was associated with reduced tumor progression. Our results indicate that by harnessing cell death in an immunogenic context, our p19(Arf) and IFN-beta combination offers a clear advantage when both genes are included in the vaccine and warrants further development as a novel immunotherapy for melanoma.