Study Of The Anti-tumor Activity Of Temozolomide Deratives And The Related DNA Adduct

Background:Temozolomide (Temozolomide, TMZ) is the second-generation alkylating drugs, which is one of the best medicines to fight against glioblastoma right at present, TMZaccount for the high fat-solubility, easily passing through the blood-brain barrier, better Curative effect, and less bone marrow inhibition. TMZ doesn’t have the antineoplastic activity itself, It can open the loops automatically to produce5-(3-methyl-triaza-1-) imidazole-4-carboxamide (MTIC) under the physiological conditions, then the MTIC will be further hydrolyzed to5-amino-imidazole-4-carboxamide (AIC) and methylhydrazine, which is a highly active cationic and was considered to be the active fragments of alkylating. However, the repairing enzyme06-methylguanine-DNA-methyltransferase (MGMT) can catalyze the06-methyl guanine transfer to the145th cysteine residues, and repair the methyl that is generated by the MGMT’s alkylation in06-methylguanine irreversibly, it can reduce the antineoplastic activity and generate the drug resistance. In order to overcome the drug resistance of tumor cells, Professor Malcolm Stevens had synthesized the TMZ derivatives which can overcome MGMT repair.Objective:The present research has not revealed the recognition and repair mechanisms that how the TMZ derivatives evade from MGMT, as well as the position where the alkylation is occurred in DNA. Based on the previous research, the paper will study the activity and stability of the TMZ derivatives further, and explore the autophagy of TMZ derivatives as well as the DNA Adduct induced by analogs, to provide theoretical foundation for designing and developing drugs which can bypassthe MGMT repair.Methods:1, MTT assay TMZ derivatives on colon and lung cancer cells IC50.2, fluorescence detection method and Western blotting TMZ derivatives and autophagy relationship.3, to establish tumor models in mice in vivo activity detected TMZ derivatives.4, UV spectroscopy measurement stability TMZ derivatives under different PH.5, HPLC-MS assay TMZ and ctDNA, nucleotide fragments and dGMP adduct situation. Results: 1,465pairs of human colon cancer cells HCT116and A549human lung cancer cells was significantly inhibited;377pairs HCT116cells was significantly inhibited, less inhibition of A549cells;253and254pairs of HCT116cells smaller effect on A549cells invalid.2, TMZ derivatives377and465were not induce autophagy.3. successfully established scid mouse tumor models;465pairs of mice did not significantly inhibit tumor25mg/kg, this experiment needs to be further verified.4, TMZ derivatives377and465is stable under acidic conditions, is easy to open the ring under alkaline conditions.5, TMZ ctDNA, dGMP nucleotide fragment or adductis not detected.