Understanding and targetting telomere maintenance in cancer

Cancer occurs through the uncontrolled growth and division of cells, which eventually leads to the development of a tumour. The number of times a cell can divide is limited by the length of specialised DNA sequences found at the end of chromosomes. These specialised sequences are called telomeres, and in normal cells they shorten with every cell division. For a cell to become cancerous it has to stop its telomeres shortening, which in turn allows the cell to continue to grow and divide. To accomplish this, cancer cells either activate an enzyme (telomerase) that adds telomeric DNA sequences to the ends of the DNA molecules, or they copy telomeric sequences from the end of one DNA molecule to another (the alternative lengthening of telomeres (ALT) pathway). The Clynes laboratory is focused on understanding the molecular mechanisms that underpin the ALT pathway and identifying new approaches to target cancer cells that use the ALT pathway. This is achieved using a variety of cutting-edge molecular biology techniques including; genome editing using CRISPR-Cas9 technology and super-resolution microscopy.

Recent research has provided important clues as to how telomere lengthening is activated in ALT cancers. We have shown that expression of a protein called ATRX, which is inactivated in most ALT cancers, suppresses telomere lengthening in ALT cells, and this suppression is likely linked to the role of ATRX in DNA replication/repair. Understanding more about how ATRX works will provide important clues for the development or identification of new drugs that inhibit this pathway. It has also recently become apparent that the telomere lengthening that occurs in ALT cancer cells is a result of the aberrant repair of DNA damage. Indeed, telomeres present a very specialised environment for the repair of DNA damage and the lab has a major interest in learning how DNA damage at telomeres is normally repaired.

Although relatively rare in cancers overall, ALT is prevalent in a specific subset of cancers including; pancreatic neuroendocrine tumours, sarcomas and several cancers of the central nervous system such as gliomas. Many of these cancers have an extremely poor prognosis and therefore our lab is interested in the identification of new drugs and approaches that could potentially be used to target ALT cancer cells. The challenge of identifying new cancer drugs can be approached in different ways. One way is understanding which gene and proteins underpin an abnormal characteristic of a cancer cell (in this case aberrant telomere lengthening or the lack of ATRX) to identify new targets for the rational design of drugs. A second ways is screening pre-existing drug libraries and testing them for their ability to limit the growth of, or preferentially kill, ALT cancer cells that lack ATRX.

For further information please contact [Email Address Removed].

Students will have the opportunity to learn several cutting-edge techniques including genome engineering using CRISPR-Cas9, immunofluorescence and super resolution microscopy.

Students will receive extensive training in all the techniques they will require to complete their project with support from the WIMM Genome Engineering and Wolfson Imaging Centre facilities for genome engineering and microscopy work respectively.

As well as the specific training detailed above, students will have access to high-quality training in scientific and generic skills, as well as access to a wide-range of seminars and training opportunities through the many research institutes and centres based in Oxford.

All MRC WIMM graduate students are encouraged to participate in the successful mentoring scheme of the Radcliffe Department of Medicine, which is the host department of the MRC WIMM. This mentoring scheme provides an additional possible channel for personal and professional development outside the regular supervisory framework.