MGMT and central nervous system cancer: MTT assays were initially employed to investigate antitumour activity of naked and AFt-encapsulated TMZ against isogenic GBM - U373V (vector control; MGMT-ve) and U373M (stably transfected with MGMT; MGMT+ve), paediatric SF188 high-grade glioma and DNA MMR-deficient CRC HCT 116 cancer cell lines as well as non-transformed MRC-5 fibroblasts.