Diffuse infiltrating low-grade gliomas (LGGs) are WHO grade 2 tumours that include oligodendrogliomas and astrocytomas. Despite their initially indolent nature, LGGs may cause considerable morbidity1 and frequently transform into higher grade lethal entities 2. The mainstay of treatment for LGGs is surgery, which can be followed by radiotherapy with chemotherapy3. However, which patients are most likely to benefit from postsurgical adjuvant treatment is not clear, and recurrence is nearly universal. Consequently, there is an urgent need to develop novel therapeutics. These efforts have been hampered by the paucity of robust pre-clinical models. This PhD project will generate novel in vitro models of genetically-defined astrocytomas and oligodendrogliomas using hTERT-immortalised oligodendrocytes and astrocytes (Fig 1). Large chromosomal deletions will be engineered in oligodendrocytes via CRISPR to recapitulate a defining feature of these tumours (1p/19q codel), and oncogenic variants associated with transformation into high grade gliomas (i.e. mutPIK3R1) will be ectopically expressed. These models will be assessed for their growth potential and evaluated as platforms for drug screens. The project has 3 main aims to be completed in consecutive years: 1) Generate hTERT-immortalised human astrocytes and oligodendrocytes with glioma-relevant genetic lesions, 2) Assess the transforming potential of PI3K and MYC in human LGG cells, and 3) Characterise the response of patient-derived and engineered cells to inhibitors of PI3K.
Figure 1. Schema for the derivation of novel in vitro models of low grade gliomas through hTERT-mediated immortalisation and CRISPR/Cas9 gene editing.