Disulfiram sensitised cytotoxicity of gemcitabine in human glioblastoma cell lines


Year:

Session type:

Sarah Brown1, Peng Liu1, Tuge Goktug1, Prasanna Channathodiyil1, John L Darling1, Weiguang Wang1
1University of Wolverhampton, Wolverhampton, United Kingdom

Background

The blood and brain barrier (BBB) and chemoresistance are the major obstacles for the success of glioblastoma multiforme (GBM) chemotherapy. It has been shown that high nuclear factor kappa B (NF?B) activity is highly related to chemoresistance. Gemcitabine (dFdC) can easily cross the BBB and gets into GBM tissues. Due to the chemoresistance of GBM cells to dFdC induced cytotoxicity, this drug is currently only used as a radiosensitiser for GBM treatment. Disulfiram (DS) is an anti-alcoholism medicine. Our previous study demonstrates that DS strongly inhibits NF?B activity and sensitises cancer cell lines to several anticancer drugs including dFdC. DS can freely pass through BBB. Therefore, we tested the chemosensitising effect of DS on dFdC in three GBM cell lines (U251MG, U87MG and U373MG).

Method

The following methodologies were used: MTT cytotoxicity, flow cytometry, western blot, EMSA, reporter gene assay, ROS activity assay, Confocal microscopy.

Results

DS was cytotoxic to GBM cell lines in a Copper (Cu)-dependent manner. Cu or DS alone was not cytotoxic. Whereas high cytotoxicity (IC50 = 150 – 250 nM) was demonstrated when DS was dosed in combination with a sub-physiological concentration of Cu (1 µM). We also tested the chemosensitising effect of DS/Cu complex on dFdC in GBM cell lines. The GBM cell lines were highly resistant to dFdC induced cell death. DS significantly sensitised the cytotoxicity of dFdC in GBM cell lines (~ 6 – 23-fold). CI-isobologram analysis indicated that the combination effect between DS/Cu and dFdC was highly synergistic. Flow cytometric data demonstrated that DS/Cu enhanced dFdC induced apoptosis. DS/Cu strongly inhibited NF-?B activity and persistently activated reactive oxygen species (ROS)-JNK and p38 pathways.

Conclusion

DS was highly toxic and synergistically sensitized the cytotoxicity of dFdC in GBM cells. The simultaneous modulation of NF?B and ROS-MAPK pathways may be responsible for the action of DS.