Caspase activation and changes in Bcl-2 family member protein expression associated with E2F-1-mediated apoptosis in human esophageal cancer cells
| Autor: | H L, Yang, Y B, Dong, M J, Elliott, T J, Liu, K M, McMasters |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Esophageal Neoplasms
Cell Survival Genetic Vectors DNA Recombinant bcl-X Protein Apoptosis Cell Cycle Proteins Retinoblastoma Protein Adenoviridae Tumor Cells Cultured Humans Cell Death Cell Cycle E2F Transcription Factors Neoplasm Proteins DNA-Binding Proteins Enzyme Activation Gene Expression Regulation Neoplastic Proto-Oncogene Proteins c-bcl-2 Caspases Myeloid Cell Leukemia Sequence 1 Protein Tumor Suppressor Protein p53 Carrier Proteins Transcription Factor DP1 Cell Division E2F1 Transcription Factor Retinoblastoma-Binding Protein 1 Transcription Factors |
| Zdroj: | Clinical cancer research : an official journal of the American Association for Cancer Research. 6(4) |
| ISSN: | 1078-0432 |
| Popis: | The prognosis for patients with esophageal cancer remains poor, prompting the search for new treatment strategies. Overexpression of E2F-1 has been shown to induce apoptosis in several cancer cell types. In the present study, the effect of adenovirus-mediated E2F-1 overexpression on human esophageal cancer cell lines Yes-4 and Yes-6 was evaluated. Cells were treated by mock infection, infection with an adenoviral vector expressing beta-galactosidase (Ad5CMV-LacZ), or E2F-1 (Ad5CMVE2F-1). Western blot analysis confirmed marked overexpression of E2F-1 in Ad5CMVE2F-1-infected cells. Overexpression of E2F-1 resulted in marked growth inhibition and rapid loss of cell viability due to apoptosis, although Yes-6 cells were somewhat more resistant to E2F-1-mediated growth inhibition than Yes-4 cells. Cell cycle analysis revealed that overexpression of E2F-1 led to G2 arrest, followed by apoptotic cell death. p53 expression remained undetectable in both cell lines after E2F-1 overexpression. The apoptosis inhibitor proteins of the Bcl-2 gene family, Bcl-2, Mcl-1, and BcI-XL, decreased at 48 h after infection in Yes-4 cells, but remained unchanged in Yes-6 cells. Levels of retinoblastoma gene product (pRb) declined at 48 h after E2F-1 infection in Yes-4 cells, at which apoptosis predominated, whereas pRb expression remained constant in Yes-6 cells. Expression of p14ARF did not change after E2F-1 infection in either cell line. Involvement of caspase 3 and caspase 6 in E2F-1-mediated apoptosis was demonstrated by cleavage of caspase 3/CPP32 and poly-ADP-ribose polymerase, as well as fragmentation of the caspase 6 substrate, lamin B. These results indicate that the sensitivity of esophageal cancer cells to E2F-1-mediated apoptosis may be related to differential expression of Bcl-2 family member proteins and suggest that the adenovirus-mediated E2F-1 gene therapy may be a promising treatment strategy for the treatment of this disease. |
| Databáze: | OpenAIRE |
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