QSAR and Chemical Read-Across Analysis of 370 Potential MGMT Inactivators to Identify the Structural Features Influencing Inactivation Potency.

-methylguanine-DNA methyltransferase (MGMT) constitutes an important cellular mechanism for repairing potentially cytotoxic DNA damage induced by guanine -alkylating agents and can render cells highly resistant to certain cancer chemotherapeutic drugs. A wide variety of potential MGMT inactivators have been designed and synthesized for the purpose of overcoming MGMT-mediated tumor resistance. We determined the inactivation potency of these compounds against human recombinant MGMT using [H]-methylated-DNA-based MGMT inactivation assays and calculated the IC values.

Effect of O6-(4-bromothenyl)guanine on different temozolomide schedules in a human melanoma xenograft model.

The DNA repair protein O(6)-alkylguanine DNA alkyltransferase (ATase) is a major component of resistance to treatment with methylating agents and nitrosoureas. Inactivation of the protein, via the administration of pseudosubstrates, prior to chemotherapy has been shown to improve the latter's therapeutic index in animal models of human tumours. We have also shown that rational scheduling of temozolomide, so that drug is administered at the ATase nadir after the preceding dose, increases tumour growth delay in these models.