Investigating anti-tumour T cell dynamics in models of primary and metastatic colorectal cancer

Kennedy, Bethany (2025). Investigating anti-tumour T cell dynamics in models of primary and metastatic colorectal cancer. University of Birmingham. Ph.D.

Preview

Kennedy2025PhD.pdf
Text - Accepted Version
Available under License All rights reserved.
Download (89MB) | Preview

Abstract

Despite the successes of immunotherapy in the treatment of several cancer types, in metastatic proficient mismatch repair (pMMR) colorectal cancer (CRC) it has shown limited beneficial impact. In CRC, liver metastases are common and represent one of the greatest clinical challenges, both worsening prognosis and impeding the response to immunotherapy. Hence, it is essential to decipher the mechanisms by which liver metastases disrupt anti-tumour immunity and how these can be targeted therapeutically. The aim of this work was to better understand the fate of intratumoural CD8 T cells, namely how populations within the tumour interface with the peripheral immune compartment and ultimately contribute to the response to metastatic disease. To do this, novel in vivo primary and metastatic orthotopic CRC models that enable the temporal labelling of immune cells were developed. Across multiple models, the dynamics and migratory capacity of CD8 T cell populations were investigated.

This work, utilising both scRNA-seq and flow cytometry, identified an intratumoural TCF-1+ PD-1+ stem-like CD8 compartment. This stem-like population actively trafficked from tumours and these ‘tumour experienced’ T cells migrated to the dLN and beyond, circulating through lymphoid tissues. Implantation of CRC cell lines within both the colon wall and liver, modelling primary and metastatic disease respectively, showed that the location of tumour cell lines did not impact the phenotype of intratumoural CD8 populations. Finally, utilising an in vivo dual liver and subcutaneous tumour model allowed for the systemic suppressive effect of liver tumours on the anti-tumour immune response to be recapitulated. This model, coupled with novel labelling of the immune compartment of liver tumours, confirmed that CD8 T cells are able to migrate between the two tumour sites; however, the migration of T cells between dual subcutaneous tumours was minimal, highlighting the importance of orthotopic models in the study of immune cell migratory dynamics. Collectively, this work has developed new tools to study the migration of immune subsets in orthotopic metastatic models of CRC and revealed new insight into the behaviour of the stem-like CD8 population in cancer.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):