Method for selecting patients responsive for cancer treatments

A method of quantifying intracellular metabolite effluxes in permeabilized cancer cells for selecting cancer patients responsive for a cancer treatment, the method comprising the steps of:

• a) providing a sample of cancer cells taken from a patient;
• b) permeabilizing said cancer cells;
• c) incubating said permeabilized cancer cells in a reaction medium for a period of time allowing biological activity of intracellular organelles and accumulation of one or more metabolites produced by said activity into the reaction medium in the presence of two or more substrates relating to a metabolite efflux or effluxes of interest, wherein the two or more substrates comprise at least glutamine and pyruvate;
• d) determining a quantity of the one or more metabolites relating to said metabolite efflux or effluxes of interest accumulated in the reaction medium during step c);
• and
• e) comparing the quantity of one or more metabolites determined in step d) to equivalent measurements performed on control samples of the same tissue type as the cancer cells;
• and
• f) if a difference between the quantity of one or more metabolites in step d) and those of the control samples indicate elevated metabolic activity of the cancer cells, contacting the cancer cells with a drug affecting a metabolic pathway or pathways relating to said metabolite efflux or effluxes of interest to determine a treatment response of the cancer cells to the drug, wherein the drug comprises a glutaminase (GLS) inhibitor.