Bortezomib administered prior to temozolomide depletes MGMT chemosensitizes glioblastoma with unmethylated MGMT promoter and prolongs animal survival

摘要

GBM cells are sensitive to BTZ due to depletion of MGMT protein and mRNA. ( ) Mean % ± standard error of the mean (S.E.M.) survival of control NHA, glioma cell lines and patient-derived cells treated with TMZ for 72 h using clonogenic assays. ( ) Mean ± S.E.M. clonogenic survival on IC doses (µM) of TMZ in methylated (M) or unmethylated (U) GBM cells. ( ) Ethidium bromide-stained agarose gel showing amplified DNA fragments corresponding to promoter methylation status in NHA and glioma cells. For positive control of unmethylated promoter HCC1569, breast cancer cells were used (Supplementary Fig.  ). MW: 93 bp, unmethylated; and 81 bp, methylated. ( ) Mean ± S.E.M. viability on IC doses (nM) of BTZ, carfilzomib or MG-132 after 48 h treatment of P3, 2012-018 and NHA. ( ) Mean ± S.E.M. viability on IC doses (nM) of BTZ after 24 or 48 h treatment of NHA, U87 and T98G. ( ) Mean % ± S.E.M. survival of tumour cells treated with BTZ for 48 h using clonogenic assays. Western blots of MGMT protein levels after TMZ dose and time for ( ) P3, ( ) T98G cells, and after BTZ treatment for ( ) P3, ( ) T98G, 24 and 48 h. % relative to control of MGMT ( ) protein and ( ) mRNA expression from P3 GBM cells after treatment. Clonogenic surviving fractions of ( ) P3, ( ) T98G and ( ) BG7 cells after treatment. Each experiment was performed in triplicate, and the data represent the mean ± S.E.M. of at least three independent experiments, *  P P P