Anti-Proliferative Effects of E2F1 Suppression in Glioblastoma Cells
Paulo R D V Godoy1, Flavia S Donaires2, Ana Paula L Montaldi2
1Department of Genetics, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil, paulo.godoy@su.se.
Abstract:
Glioblastoma (GBM) is an aggressive malignant brain tumor; surgery, radiation, and temozolomide still remain the main treatments. There is evidence that E2F1 is overexpressed in various types of cancer, including GBM. E2F1 is a transcription factor that controls the cell cycle progression and regulates DNA damage responses and the proliferation of pluripotent and neural stem cells. To test the potentiality of E2F1 as molecular target for GBM treatment, we suppressed the E2F1 gene (siRNA) in the U87MG cell line, aiming to inhibit cellular proliferation and modulate the radioresistance of these cells. Following E2F1 suppression, associated or not with gamma-irradiation, several assays (cell proliferation, cell cycle analysis, neurosphere counting, and protein expression) were performed in U87MG cells grown as monolayer or neurospheres. We found that siE2F1-suppressed cells showed reduced cell proliferation and increased cell death (sub-G1 fraction) in monolayer cultures, and also a significant reduction in the number of neurospheres. In addition, in irradiated cells, E2F1 suppression caused similar effects, with reduction of the number of neurospheres and neurosphere cell numbers relative to controls; these results suggest that E2F1 plays a role in the maintenance of GBM stem cells, and our results obtained in neurospheres are relevant within the context of radiation resistance. Furthermore, E2F1 suppression inhibited or delayed GBM cell differentiation by maintaining a reasonable proportion of CD133+ cells when grown at differentiation condition. Therefore, E2F1 proved to be an interesting molecular target for therapeutic intervention in U87MG cells.
Insights
Targeting the E2F1 gene in glioblastoma (GBM) cells reduced proliferation and increased cell death. Suppressing E2F1 also impacted GBM stem cells and radiosensitivity, suggesting E2F1 as a potential therapeutic target.
Area of Science:
- Neuro-oncology
- Molecular Biology
- Cancer Research
Background:
- Glioblastoma (GBM) is an aggressive brain tumor with limited treatment options.
- E2F1 is a transcription factor overexpressed in GBM, regulating cell cycle and proliferation.
- E2F1's role in GBM stem cell maintenance and radioresistance requires further investigation.
Purpose of the Study:
- To investigate the therapeutic potential of targeting E2F1 in GBM.
- To assess the effect of E2F1 suppression on U87MG cell proliferation, cell cycle, and radioresistance.
Main Methods:
- E2F1 gene suppression using siRNA in U87MG glioblastoma cells.
- Assays included cell proliferation, cell cycle analysis, neurosphere formation, and protein expression.
- Experiments were conducted on cells grown in monolayer and as neurospheres, with and without gamma irradiation.
Main Results:
- E2F1 suppression reduced U87MG cell proliferation and increased cell death in monolayer cultures.
- Neurosphere formation and cell numbers were significantly reduced upon E2F1 suppression, particularly after irradiation.
- E2F1 inhibition delayed GBM cell differentiation, maintaining CD133+ cell populations.
Conclusions:
- E2F1 plays a crucial role in the maintenance of glioblastoma stem cells.
- E2F1 suppression demonstrates potential for enhancing radiosensitivity in GBM.
- E2F1 is a promising molecular target for novel glioblastoma therapies.
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