RESUMO
BACKGROUND: Telomerase, a ribonucleoprotein enzyme mainly consisted of a catalytic protein subunit human telomerase reverse transcriptase (hTERT) and a human telomerase RNA component, is responsible for maintaining telomeres. Telomerase over-expression correlates significantly with tumors and is a prognostic marker. However, telomerase over-expression in breast cancers and the effect of telomerase inhibition as a candidate cancer therapy are unknown. METHODS: We used the dominant-negative mutant of hTERT (DN-hTERT) to inhibit telomerase activity on human breast adenocarcinoma cell line MCF-7 by transfection. Telomeric repeat amplification protocol assays and real-time quantitative RT-PCR were performed to investigate telomerase activity as well as expression of hTERT. Telomere length was measured by the flow-fluorescence in situ hybridization assay. Cell proliferation was assessed by the WST-8 assay, and apoptosis was evaluated by flow cytometry. The tumor formation ability of MCF-7 cells was investigated by transplanting cells subcutaneously into BALB/c nude mice. RESULTS: Ectopic expression of DN-hTERT caused dramatically inhibition of telomerase activity and reduction of telomere length. Telomerase inhibition induced growth arrest and apoptosis of MCF7 cells in vitro and loss of tumorigenic properties in vivo. CONCLUSION: This study shows that telomerase inhibition by DN-hTERT can effectively inhibit the cell viability and tumorigenicity of MCF7 cells and is an attractive approach for breast cancer therapy.
Assuntos
Apoptose , Neoplasias da Mama/prevenção & controle , Proliferação de Células , Genes Dominantes , Telomerase/antagonistas & inibidores , Animais , Neoplasias da Mama/enzimologia , Neoplasias da Mama/patologia , Feminino , Citometria de Fluxo , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Telomerase/genética , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The aim of the study was to analyze the clinical efficacy and safety of olfactory ensheathing cell (OEC) transplantation for treating patients with chronic, complete spinal cord injury (SCI). Six patients with six chronic complete spinal cord injuries were recruited and treated with autologous OEC transplantation and followed for 24 months. The scores from before and after transplantation were analyzed. This was a self-control experiment. There was significant amelioration in the scores of the standard neurological classification of spinal cord injury made by the America Spinal Cord Injury Association (ASIA) and the International Association of Neurorestoratology-Spinal Cord Injury Functional Rating Scale (IANR-SCIFRS) following OEC transplantation with 24 months of follow-up. No clinical complications were observed. OEC transplantation would appear to be clinically safe and may promote the neurofunctional recovery of SCI based on data from six patients. This manuscript is published as part of the International Association of Neurorestoratology (IANR) supplement issue of Cell Transplantation.
