title: Telomerase activity in response to mild oxidative stress.
abstract: We have analysed telomerase activity to determine whether it can be modified when BCL-2 is endogenously overexpressed in response to a mild oxidative stress treatment as part of a survival mechanism, in contrast with an exogenous bcl-2 overexpression due to a retroviral infection. Endogenous bcl-2 overexpression was induced after a low oxidative insult of H2O2 in mice primary lung fibroblasts and L929 cell, whereas bcl-2 exogenous overexpression was performed using a retroviral infection in L929 cells. Telomerase activity was quantified in Bcl-2 overexpressing cells by the TRAP assay. When the cells were treated with different H2O2 concentrations, only those exposed to 50 μM showed increased telomerase activity. This correlates with BCL-2 expression as part of the endogenous response to mild oxidative stress. Oxidative stress generated during the toxic mechanism of chemotherapeutic drugs might induce BCL-2 increment, enhancing telomerase activity and reactivating the oncogenic process. Clinical trials should take into consideration the possibility of telomerase activation following increased BCL-2 expression when treating patients with ROS (reactive oxygen species) generation by anti-cancer drugs.
authors.affiliation: Departmento Ciencias de la Salud, DCBS, Universidad Autonoma Metropolitana Iztapalapa AP 55-535 CP 09340, Mexico DF.
authors.forename: Norma Edith
authors.initials: NE
authors.lastname: López-Diazguerrero
authors.forename: Gloria Erandi
authors.initials: GE
authors.lastname: Pérez-Figueroa
authors.forename: Cintia Mayel
authors.initials: CM
authors.lastname: Martínez-Garduño
authors.forename: Adriana
authors.initials: A
authors.lastname: Alarcón-Aguilar
authors.forename: Armando
authors.initials: A
authors.lastname: Luna-López
authors.forename: María Concepción
authors.initials: MC
authors.lastname: Gutiérrez-Ruiz
authors.forename: Mina
authors.initials: M
authors.lastname: Königsberg
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D004789:Enzyme Activation; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D015870:Gene Expression; D005822:Genetic Vectors; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008168:Lung / Q000166:cytology; D051379:Mice; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D061251:Primary Cell Culture; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012190:Retroviridae; D015398:Signal Transduction; D019098:Telomerase / Q000378:metabolism*
chemical_list: D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D019098:Telomerase