RESUMO
Glucocorticoids (GCs) are widely used in chemotherapy of hematological malignancies, particularly leukemia. Their effect is mediated by glucocorticoid receptor (GR), a well-known transcription factor. Besides their therapeutic impact, GCs may cause a number of side effects leading to various metabolic complications. The goal of immediate interest is testing glucocorticoid analogs capable of induction/enhancement of GR transrepression, but preventing GR dimerization and transactivation leading to side effects. In this work we have investigated effects of a promising new selective GR agonist, 2-(4-acetoxyphenyl)-2-chloro-N-methylethylammonium chloride (CpdA), on CEM and K562 leukemia cells. Both cell lines express functional GR. CpdA compared with the glucocorticoid fluocinolone acetonide (FA) exerted more prominent cytostatic and apoptotic effects on the cells. Both cell lines exhibited sensitivity to CpdA, demonstrating a good correlation with the effects of FA on cell growth and viability. In contrast to FA, CpdA did not induce GR transactivation evaluated by no obvious increase in expression of GR target (and dependent) gene FKBP51. At the same time, luciferase assay showed that CpdA efficiently activated transrepression of NF-κB and AP-1 factors. We also evaluated the effect of combined action of CpdA and the proteasome inhibitor Bortezomib. The latter induced a caspase-dependent apoptosis in both T-cell leukemia cell lines. By treatment of CEM cells with different CpdA/GC and Bortezomib doses, we have designed a protocol where CpdA shows potentiating effect on Bortezomib cytotoxic activity. Generally, the present work characterizes a novel non-steroid GR ligand, CpdA, as a promising compound for possible application in leukemia chemotherapy.
Assuntos
Acetatos/farmacologia , Apoptose/efeitos dos fármacos , Citostáticos/farmacologia , Leucemia/metabolismo , Receptores de Glucocorticoides/agonistas , Tiramina/análogos & derivados , Ácidos Borônicos/farmacologia , Bortezomib , Linhagem Celular Tumoral , Fluocinolona Acetonida/farmacologia , Humanos , Células K562 , Ligantes , NF-kappa B/genética , NF-kappa B/metabolismo , Pirazinas/farmacologia , Receptores de Glucocorticoides/metabolismo , Proteínas de Ligação a Tacrolimo/genética , Proteínas de Ligação a Tacrolimo/metabolismo , Fator de Transcrição AP-1/genética , Fator de Transcrição AP-1/metabolismo , Tiramina/farmacologiaRESUMO
Interaction of immunocompetent cells with extracellular matrix is one of the main stages in their homing and circulation. In this connection we investigated quantitative and dynamic parameters of interaction between splenocytes and 3D collagen matrix in vitro. It was found out that, about 20% of mouse spleen lymphocytes exhibited ability to bind to type I collagen that reflected as their adhesion to and/or migration in collagen matrix. The number of lymphocytes capable of the interaction with collagen gained successively as far as the time of their incubation on collagen matrix was increased and reached maximum by 24 h. The lymphocyte-collagen interaction was energy-dependent and engaged collagen receptors, which probably have been already expressed on cells before spleen lymphocytes were isolated. The series of intracellular interchanges as activation of protein kinase C, assembly of actin filaments and depolymerization of tubulin microtubules were critical for lymphocytes to adhere to and further to migrate in collagen matrix. Long lasting incubation (24 h and more) of lymphocytes in adhesion excluding conditions did not reduce the number of cells able to interact with collagen, but to a great extent changed mechanisms providing their adhesion and/or migration.
