Spatial Analysis of Nucleotide Metabolism: From CRISPR Knockout Cancer Cells to MALDI Imaging of Tumors.

Cancer cells depend on nucleotides for proliferation. Inhibition of nucleotide metabolism by antimetabolites is a well-established anticancer therapy. However, resistance and toxicity to antimetabolite treatments reduce their effectiveness. Here, we focus on the pyrimidine de novo synthesis pathway, which is crucial for cancer cell proliferation, yet its pharmacological targeting in cancer has been without much clinical success so far. Hence, it is important to understand how cancer cells cope with the insufficiency of this pathway. Here, we describe a procedure to prepare subcutaneous tumor model deficient in de novo pyrimidine synthesis. For examination of metabolic responses to de novo synthesis blockade in tumors, we propose application of MALDI imaging that allows spatially resolved examination of metabolic responses to de novo synthesis blockade in tumors.