Abstract
BACKGROUND
Brain cancers, including medulloblastomas and gliomas, are a major cause of death in children and adults. We reported that PID1 (Phosphotyrosine Interaction Domain containing 1) is a growth suppressor in medulloblastomas and gliomas (PMID: 24300787). PID1 also enhances the anti-tumor effects of chemotherapy (PMID: 28400607). We are now seeking to better understand the structure and mechanism of PID1, in order to utilize this knowledge to develop innovative PID1-based therapies.
METHODS
PID1 mutants were expressed in E. coli as MBP fusion proteins, purified and used for MALS analysis. Additional epitope tagged PID1 constructs (HA, V5, tGFP, eGFP) were generated, expressed in mammalian cells and analyzed by western blots, immunoprecipitation, and functional assays.
RESULTS
We carried out screening and testing of multiple mutants of purified PID1 and characterized them. Experiments in cell culture supported presence of similar findings in mammalian cells. Colony assays in glioma and medulloblastoma cell lines identified a region in PID1 that confers the most robust growth-inhibitory effect. Experiments are underway to further refine the boundaries and characteristics of this growth-inhibitory region.
CONCLUSIONS
This project, which is focused on better understanding of the structure and function of PID1, is uncovering novel aspects of its molecular function. Insights gained from this work will guide studies to develop innovative PID1-based therapies for gliomas and medulloblastomas.