Identifying unique vulnerabilities of polyploid tumour cells to enhance radiation sensitivity

Supervisors: Dr Lucy Brooks, Professor Peter McHugh

Project Overview

Glioblastoma is the most common intrinsic primary brain tumour with an average survival of ~1 year. This dismal prognosis can be attributed to the pronounced resistance to existing therapeutic interventions, encompassing surgery, chemotherapy, and radiation. Consequently, there is an urgent need to understand and target resistance mechanisms in this disease.

 We have recently discovered a previously unappreciated mechanism by which tumour cells resist treatment. Following radiation and chemotherapy, a large proportion of tumour cells enter a polyploid state due to mitotic failure. Importantly these cells are long lasting, can resume cell division and generate proliferative progeny. Thus, polyploid cells may play a critical role in cancer recurrence and represent and important therapeutic target.

This project seeks to identify unique vulnerabilities of polyploid cells that can be targeted to improve radiation sensitivity and enhance survival in glioblastoma.

Using whole genome CRISPR screening of patient derived glioblastoma cells to reveal genetic dependencies of the polyploid population following radiation. Focusing on genes that drop out in polyploid cells, we will perform enrichment analysis to detect shared biological patterns among the top hits to prioritise biologically important genes and pathways associated with polyploidy. The top 50 hits will be validated in patient-derived GSCs using an arrayed CRISPR knockout approach. The impact of gene knockouts on polyploidy and treatment sensitivity will be evaluated using a multiplexed mass cytometry method developed by collaborator Dr Chris Tape (UCL). FUCCI live imaging will also be used to determine if cells enter a polyploid state before death. By identifying these dependencies, we hope to uncover new strategies to enhance treatment sensitivity, which will then be advanced to in vivo preclinical studies.

Training Opportunities

You will receive training in techniques including patient-derived glioblastoma culture, whole-genome CRISPR screening, mass cytometry, live imaging and computational analysis.

References

Quinton, R.J., 2020. Whole genome doubling confers unique genetic vulnerabilities on tumors (Doctoral dissertation, Boston University).

Brooks, L.J., Clements, M.P., Burden, J.J., Kocher, D., Richards, L., Devesa, S.C., Zakka, L., Woodberry, M., Ellis, M., Jaunmuktane, Z. and Brandner, S., 2021. The white matter is a pro-differentiative niche for glioblastoma. Nature communications, 12(1), p.2184.

Brooks, L.J., Ragdale, H.S., Hill, C.S., Clements, M. and Parrinello, S., 2022. Injury programs shape glioblastoma. Trends in Neurosciences, 45(11), pp.865-876.