Pediatric high grade glioma (pHGG) remains a fatal disease with no cure in sight. Missense somatic mutations affecting histone H3.3 proteins are now accepted as the hallmark of pediatric diffuse intrinsic pontine gliomas (DIPG) and non-brain stem pHGG. However, little is known about the mechanistic role of G34R/V mutation in pHGG.
There is urgent unmet clinical need to identify drug targets for pHGG with H3.3 G34R mutation. Through a genome wide CRISPR/Cas9, we found that some genetic vulnerability specific for KNS42 cell lines (G34V mutant). We wish to validate these findings using multiple cell lines with H3.3.G34 mutation for obtaining reliable data regarding these potential targets.
We conducted genome-wide CRISPR/Cas9 screening using KNS42 cells and several patient-derived pHGG cell lines with wild type histones. We found that depletion of PHIP, HCN2 and ITRP1 inhibited the proliferation of KNS42 cells specifically. Therefore, we propose to further validate these hits using additional H3.3G34 mutant tumor lines. If validated, it will shed light on not only the mechanistic insight into tumorigenesis of H3.3G34 mutant pHGG, but also provide a potential therapeutic targets for H3.3G34 pHGG.
What are the goals of this project?
The goals of this project are to determine how depletion pf candidate genes (PHIP, HCN2 and ITRP1) using CRISPR/Cas9 affects the proliferation of H3.3G34V and H3.3G34R mutant pHGG cells and to elucidate molecular basis for the specific dependence of H3.3G34 mutant lines on these genes
What is the impact of this project?
pHGG is the leading cause of cancer death in children with no effective therapy strategy. Our studies will expand the mechanistic understanding for the tumorigenesis of pHGG with H3.3H34R mutation. More importantly, some of the genes such as ITRP1, if validated in mouse models, will provide novel drug targets for the treatment in the future.
Why the CBTN request is important to this project?
Currently, we are only aware one H3.3G34V line. The precious lines CBTN generated are extremely useful for the studies. The biospecimens and patient derived tumor models are greatly useful for the basic and translational research in understanding the mechanism of the disease thus helping develop effective therapeutically method. The H3.3G34R cell line will be useful for us to study the function of genes we identified.
The Children's Brain Tumor Network contributed to this project by providing H3.3G34R cell lines.
Yinnan Chen, Xu Zhang
High-grade glioma/astrocytoma (WHO grade III/IV)
High-grade Gliomas (HGG) in children nearly always result in a dismal prognosis. Although novel therapeutic approaches are currently in development, preclinical testing has been limited, due to a lack of pediatric specific HGG preclinical models. These models are needed to help test the effective