Atividade da telomerase e proliferação de células de melanoma HS839.T submetidas ao AZT
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Data
2009
Autores
Souza Sobrinho, Celestino Prospero de [UNIFESP]
Orientadores
Gragnani, Alfredo [UNIFESP]
Tipo
Dissertação de mestrado
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Introdução: O melanoma é decorrente de um crescimento celular descontrolado, com perda de inibição por contato e alterações no núcleo, afetando a manutenção dos telômeros. A telomerase, responsável pela síntese do telômero, protege o final da molécula de DNA. Sua atividade está ausente na maioria das células somáticas humanas e presente em quase todas linhagens de células tronco, germinativas e em mais de 90% dos tumores humanos. Estudos sugerem que a progressão de doenças malignas depende da reativação da telomerase, e que um agente inibidor dessa enzima poderia ser uma droga antitumoral efetiva, entre elas, o azidotimidinatrifosfato (AZT), sendo provado que o uso dessa droga em algumas neoplasias inibe in vitro sua ação. Objetivo: Avaliação da atividade da telomerase e da proliferação de células imortalizadas de melanoma Hs839T catalogo CRL-7572 submetidas à ação do AZT. Métodos: Foram utilizadas, linhagens de células de melanoma Hs839T catalogo CRL-7572, adquiridas via American Type Culture Collection, derivada da pele de um indivíduo caucasiano do sexo feminino de 42 anos. As células foram cultivadas em meio de cultura, suplementadas com diferentes concentrações de AZT em triplicata com 50, 100 e 200µM por 24h e 48h e comparados seus efeitos ao grupo controle. A avaliação da proliferação celular foi realizada pela técnica de MTT. A detecção da atividade da telomerase por KIT TRAPEZE® RT s7710 e PCR ELISA. Resultados: No tempo de 24 horas, quando comparado ao grupo controle, não houve inibição da proliferação celular e da atividade da telomerase da linhagem de melanoma Hs839T catalogo CRL-7572, embora sugira tendência à diminuição, quando comparados os grupos controle e 200µM. No tempo de 48 horas, houve uma diminuição momentânea, seguida de rápida recuperação, sugerindo que as células de linhagem utilizadas neste estudo são sensíveis ao AZT, mas que recuperam a atividade enzimática e proliferativa. Conclusão: A ação do AZT em células de melanoma HS839.T catalogo CRL-7572 estudadas nas concentrações e tempos propostos, não inibiu a atividade da telomerase e não afetou a proliferação celular.
Introduction: Melanoma is caused by an uncontrolled cell growth, with lossof inhibition contact and changes in the nucleus, affecting the maintenance of telomeres. Telomerase, responsible for telomere synthesis, protects the end of the DNA molecule. Its activity is absent in most human somatic cells and present in almost all lines of stem cells, germinatives, and in more than 90% of human tumors. Studies suggest that the malignancy progression depends on the telomerase reactivation, and that an inhibitor of this enzyme could be an effective antitumor drug, including the Azidothymidine-triphosphate (AZT) and proved that the use of this drug in some neoplasms inhibits their action “in vitro”. Objective: Evaluation of telomerase activity and proliferation of melanoma cells immortalized Hs839T catalog CRL-7572 subjected to the AZT action. Methods: We used melanoma cell lines of Hs839T catalog CRL-7572, acquired through American Type Culture Collection, derived from the skin of a 42-year-old Caucasian female person. The cells were grown in culture environment supplemented with different AZT concentrations in triplicate 50, 100 and 200µM) withim 24 and 48 hours and its effects compared to the control group. The cell proliferation evaluation was performed by MTT. Detection of telomerase activity by KIT S7710 TRAPEZE ® RT and PCR ELISA. Results: In 24 hours time, when compared to the control group, there was no inhibition of proliferation cell and telomerase activity, although there was tendency to decrease when compared to the control group and 200µM. In 48 hours time, there was a momentary decrease, followed by rapid recovery, suggesting that the cell lines used in this study are sensitive to AZT, but they recover the enzyme activity and proliferation. Conclusion: The action of AZT in melanoma cells HS839.T studied in the proposed concentrations and times did not inhibit telomerase activity and did not affect cell proliferation.
Introduction: Melanoma is caused by an uncontrolled cell growth, with lossof inhibition contact and changes in the nucleus, affecting the maintenance of telomeres. Telomerase, responsible for telomere synthesis, protects the end of the DNA molecule. Its activity is absent in most human somatic cells and present in almost all lines of stem cells, germinatives, and in more than 90% of human tumors. Studies suggest that the malignancy progression depends on the telomerase reactivation, and that an inhibitor of this enzyme could be an effective antitumor drug, including the Azidothymidine-triphosphate (AZT) and proved that the use of this drug in some neoplasms inhibits their action “in vitro”. Objective: Evaluation of telomerase activity and proliferation of melanoma cells immortalized Hs839T catalog CRL-7572 subjected to the AZT action. Methods: We used melanoma cell lines of Hs839T catalog CRL-7572, acquired through American Type Culture Collection, derived from the skin of a 42-year-old Caucasian female person. The cells were grown in culture environment supplemented with different AZT concentrations in triplicate 50, 100 and 200µM) withim 24 and 48 hours and its effects compared to the control group. The cell proliferation evaluation was performed by MTT. Detection of telomerase activity by KIT S7710 TRAPEZE ® RT and PCR ELISA. Results: In 24 hours time, when compared to the control group, there was no inhibition of proliferation cell and telomerase activity, although there was tendency to decrease when compared to the control group and 200µM. In 48 hours time, there was a momentary decrease, followed by rapid recovery, suggesting that the cell lines used in this study are sensitive to AZT, but they recover the enzyme activity and proliferation. Conclusion: The action of AZT in melanoma cells HS839.T studied in the proposed concentrations and times did not inhibit telomerase activity and did not affect cell proliferation.
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Citação
SOUZA SOBRINHO, Celestino Prospero de. Atividade da telomerase e proliferação de células de melanoma HS839.T submetidas ao AZT. 2009. 80 f. Dissertação (Mestrado em Ciências) - Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, 2009.