Glioblastoma is the most malignant brain tumor with high mortality. Cancer stem cells are thought to be crucial for tumor initiation and its recurrence after standard therapy with radiation and temozolomide (TMZ) chemotherapy. Protein tyrosine phosphatase receptor type Z (PTPRZ) is an enzyme that is highly expressed in glioblastoma, especially in cancer stem cells.
The research group of Professor Masaharu Noda and Researcher Akihiro Fujikawa of the National Institute for Basic Biology (NIBB) showed that the enzymatic activity of PTPRZ is requisite for the maintenance of stem cell properties and tumorigenicity in glioblastoma cells. PTPRZ knockdown strongly inhibited tumor growth of C6 glioblastoma cells in a mouse xenograft model. In addition, the research team discovered NAZ2329, an allosteric inhibitor of PTPRZ, in collaboration with ASUBIO Pharma Co. Ltd.. NAZ2329 efficiently suppressed stem cell-like properties of glioblastoma cells in culture, and tumor growth in C6 glioblastoma xenografts. These results indicate that pharmacological inhibition of PTPRZ is a promising strategy for the treatment of malignant gliomas.