Opposing roles of E2Fs in cell proliferation and death.
Progression through the cell cycle is dependent upon the temporal and spatial regulation of the various members of the E2F family of transcription factors. Two of these members, E2F1 and E2F4 have opposing roles in cell cycle progression, which were defined over a decade ago. While E2F1 is an activator of cell cycle progression, E2F4 functions as a transcriptional repressor. Recent data indicate that these transcription factors also play a role in the cellular response to DNA damage. In the case of E2F1, its overexpression leads to apoptosis. In contrast, the decreased expression of E2F4, in response to siRNA-mediated knockdown or to certain therapeutic agents, induces apoptosis. Conversely, increased levels of E2F4 may confer resistance to apoptosis-inducing therapies used in the clinic. The balance between the activities of these two proteins in tumor cells is of great interest. Directed control of E2F1 and E2F4 action may lead to better diagnosis of disease and improved therapeutic modalities.
Crosby
Meredith E
ME
Department of Cancer Biology, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Almasan
Alexandru
A
D000818:Animals; D017209:Apoptosis; D018797:Cell Cycle Proteins / Q000502:physiology*; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D004268:DNA-Binding Proteins / Q000502:physiology*; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D050704:E2F4 Transcription Factor; D005786:Gene Expression Regulation; D016147:Genes, Tumor Suppressor; D006801:Humans; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology; D014157:Transcription Factors / Q000502:physiology*
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D050704:E2F4 Transcription Factor; C493762:E2F4 protein, human; D014157:Transcription Factors