The University of Edinburgh
Tumour infiltrating T cells in non-small cell lung cancer and their interactions with cancer-associated fibroblasts
Abstract
dc:description.abstractThe immune response to cancer is dependent on functionally efficient cytotoxic T lymphocytes (CTL). Checkpoint inhibition therapy is aimed at reinvigorating local cytotoxic T cells, however the rate of immunotherapy failure in non-small cell lung cancer (NSCLC) is as high as 80%. An improved mechanistic understanding of immunosuppressive pathways in NSCLC is important to develop novel diagnostic and therapeutic approaches. Cancer associated fibroblasts (CAFs) are the most abundant stromal cells of the tumour microenvironment (TME) and dampen the cytotoxic T cell (CTL) response in other solid tumours. Recently, CD39 has emerged as a marker to identify tumour relevant T cells and CD39 expression on CTL is correlated with T cell exhaustion. CD39+CD8+T cells often co-express the tissue resident memory marker CD103 and display an exhausted tissue resident memory T cell phenotype that shows cytotoxicity against neoplastic cells. CD39 acts in concert with CD73 to generate adenosine and thereby promote immunosuppression in the TME. Previous work from our group has shown that CAFs drive a CD39+CD103- CD4+ and a CD39+CD103+ CD8+ T cell population. This thesis will investigate the expression and spatial distribution of CD39, CD103 and CD73 in NSCLC, with a focus on tumour infiltrating T cells; and assess the effect of CAF – T cell crosstalk on the T cell phenotype, the CAF secretome, and the adenosine pathway. In the first results chapter, peripheral blood – and tissue samples of non-cancerous lung (NCL) and tumour tissue from early NSCLC patients were used to assess the expression of CD39, CD103 and CD73 within immune – and non-immune cell compartments by flow cytometry. Spatial patterns of CD39, CD103 and CD73 amongst CD4+ and CD8+ T cells were quantified in a cohort of 162 early treatment naïve NSCLC patients using multiplex-immunofluorescence and related to patient outcome. It was found that high expression of CD39 amongst CD4+ T cells relates to poor recurrence free survival (RFS), whereas a high density of CD39+CD103+CD8+ T cells within tumour nest areas relates to improved survival at 5 years. In the second results chapter, bulk RNASeq (Nanostring nCounter) was used to assess the phenotype of T cells isolated from NCL and the TME, and the effect of co-culture with CAFs. This revealed that coculture with CAFs mirrored some transcriptome changes seen in T cells isolated from the TME. Next, the effect of T cells on CAFs was evaluated by investigating the CAF secretome, revealing that T cell cytokines induce an inflammatory CAF secretome profile in vitro. In the final results chapter, flow cytometry was used to show that CAFs and T cells upregulate surface markers involved in adenosine production following CAF – T cell crosstalk. It is shown that this 5 translates to an increased synthesis of AMP and adenosine. Finally, in vitro experiments show adenosine results in proliferative inhibition amongst T cells and upregulates the CAF marker fibroblast activation protein (FAP). Spatial transcriptomics was performed to investigate the transcriptome of stromal regions with high CD73 expression. In conclusion, this thesis describes the T cell landscape in human NSCLC with a focus on CD39, and shows that CAF – T cell crosstalk results in a significant change in the CAF secretome as well as increased adenosine synthesis driven by NSCLC CAFs.
Degree
thesis:*- Grantor dc:publisher
- The University of Edinburgh
- Year dc:date.issued
- 2024
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Koppensteiner, Lilian
- Advisors dc:contributor.advisor
-
- Akram, Ahsan
- Dhaliwal, Kevin
Subjects
dc:subject × 9Rights
- Language dc:language.iso
- en
Identifiers
dc:identifier.*- Identifier URI
- http://dx.doi.org/10.7488/era/5480
- OAI identifier oai:identifier
- oai:era.ed.ac.uk:1842/42927