Method for suppressing multiple drug resistance in cancer cells

摘要

Methods for treating and preventing the onset and maintainance of multiple drug resistance (MDR) in animals undergoing chemotherapy for cancer are provided. According to the methods, target cells are depleted of adenosine 5'-monophosphate (AMP) and adenosine 5'-triphosphate (ATP) such that the cells are unable to support P-glycoprotein activity. According to one method, a population of target cells is obtained from a host and assayed for loss of methylthioadenosine phosphorylase (MTAse) activity. MTAse catabolizes methylthioadenosine to adenine for endogenous salvage incorporation into the intracellular AMP pool. MTAse deficient cells are treated with a purine synthesis inhibitor, such as L-alanosine, which starves the cells of adenine and suppresses P-glycoprotein activity. MTAse competent cells are also treated for MDR with purine synthesis inhibitors. In conjunction with treatment according to the invention, MTAse competent and deficient cells are also treated for malignancy with other anti-cancer drugs. A method for protecting non-malignant cells from adenine starvation during treatment of malignant cells according to the invention is provided.