Evaluation Of Lenalidomide Activity On Glioblastoma Cell Lines In Vitro

Purpose: Thalidomide analog, Lenalidomide (Revlimid ) is a chemotherapeutic agent. In this study, lenalidomide was used in human glioblastoma multiforme (GBM) cell lines to determine its pro-apoptotic, anti-proliferative and radiosensitizing properties. Methods: The GBM cells were treated with lenalidomide [0, 1, 5, 30, 60 μM] before ultravioletB (UVB) [0, 50, 100 mj] or γ -irradiation [0, 5, 20 Gy], and kept in drug for 5 days. Viable cell numbers were determined by trypan blue exclusion. The cell proliferation index was assessed by[ 3H]-Thymidine incorporation. Apoptosis was assessed by flow cytometry with Sub G0 gating and the activation of caspase-8 and caspase-9 after the treatments were completed. Results: Lenalidomide alone or in combination with UVB or γ-irradiation did not have a significant effect on cell death. Lenalidomide had minimal synergistic effect with γ-irradiation to reduce cell growth. Lenalidomide when used alone had an insignificant stimulatory effect on cell proliferation in GBM cells at doses 1-30 μM. Lenalidomide did not activate caspase-8 or caspase-9 pathways. Conclusions: Lenalidomide had a weak synergistic effect with γ-irradiation in decreasing cell growth in vitro. It may not be a therapeutic agent in the in the absence of γ-irradiation for the treatment of GBM.