Inducing Tertiary Lymphoid Structures in Metastatic Colorectal Cancer to Enable Effective Immunotherapy for Advanced Disease

PROJECT OVERVIEW

The generation and propagation of adaptive immune responses are normally confined to secondary lymphoid organs (SLOs), specialised tissues in which complex stromal cell networks coordinate interactions required for effective lymphocyte activation and differentiation. By concentrating rare immune populations within defined anatomical niches, SLOs facilitate efficient immune responses. However, chronic inflammatory conditions can trigger the de novo formation of organised lymphoid aggregates in non-lymphoid tissues, redistributing adaptive immune function to sites of local pathology. These structures, termed tertiary lymphoid structures (TLS), are increasingly recognised as important regulators in both inflammatory disease and cancer. TLS exist along a continuum of organisational complexity, ranging from rudimentary immune aggregates to highly structured lymphoid tissues containing germinal centres, high endothelial venules (HEVs) and specialised stromal cell networks.While the presence of TLS is associated with improved prognosis and enhanced responses to immunotherapy across multiple solid cancers, the mechanisms governing their formation, maturation and function remain controversial. It is unclear whether immature and mature TLS represent sequential stages of development, what molecular pathways drive this process, and how local tissue environments influence TLS organisation and function. These questions are of particular importance in colorectal cancer (CRC), where liver metastases remain a major cause of cancer-related mortality and where current immunotherapies benefit only a minority of patients. Therapeutic induction of TLS therefore represents a promising strategy to enhance anti-tumour immunity and improve patient outcomes. Supporting this concept, Mestag Therapeutics has developed MST-0312, a novel bispecific agent designed to activate lymphotoxin-β receptor (LTβR) signalling selectively in inflammatory FAP⁺ fibroblasts, thereby promoting TLS formation within tumours.

Progress in understanding TLS biology has been hampered by the lack of suitable experimental models. TLS are observed in many human cancers but are rarely detected in conventional murine tumour models that have rapid growth kinetics. Consequently, the stromal remodelling and immune organisation required for TLS formation often fail to develop. Orthotopic implantation of mouse colon tumour-derived organoids has emerged as a highly relevant model of CRC that more closely recapitulates human disease. These slowly developing tumours can be monitored longitudinally by colonoscopy and provide a unique experimental window in which to manipulate the tumour microenvironment and investigate the processes underlying TLS development.

This DPhil project will test the hypothesis that local fibroblast reprogramming through LTβR signalling can induce TLS within both primary colorectal tumours and metastatic lesions. By combining advanced in vivo photolabeling models with single-cell, spatial and functional analyses, this project will define the stromal and immune mechanisms regulating TLS development and determine how these structures influence anti-tumour immunity. Ultimately, this work aims to establish a mechanistic framework for therapeutically inducing TLS in advanced CRC.

KEYWORDS

Tumour-immunology, TLS, machine-learning, scRNAseq, systems-immunology

TRAINING OPPORTUNITIES

The project will provide practical training in several state-of-the-art technologies, including high-parameter spectral flow cytometry for immune phenotyping, multiplex immunofluorescence imaging for spatial analysis of tumour tissues and single-cell genomic approaches for characterising cellular heterogeneity and molecular pathways. The student will also gain experience in tissue processing, cell isolation, antibody staining and experimental immunology techniques. In addition to laboratory training, the student will develop computational and quantitative skills through the analysis of complex datasets generated by imaging and single-cell technologies. Training will include image analysis using artificial intelligence and machine-learning-based approaches, bioinformatics pipelines for single-cell data analysis and integration of spatial and transcriptional datasets. Exposure to these complementary experimental and computational approaches will provide a strong foundation and prepare the student for their subsequent DPhil project.

KEY PUBLICATIONS

Dean I, Lee CYC, Tuong ZK, Li Z, Tibbitt CA, Willis C, Gaspal F, Kennedy BC, Matei-Rascu V, Fiancette R, Nordenvall C, Lindforss U, Baker SM, Stockmann C, Sexl V, Hammond SA, Dovedi SJ, Mjösberg J, Hepworth MR, Carlesso G, Clatworthy MR, Withers DR. Rapid functional impairment of natural killer cells following tumor entry limits anti-tumor immunity. Nat Commun. 2024 Jan 24;15(1):683. doi: 10.1038/s41467-024-44789-z.

Lee CYC, Kennedy BC, Richoz N, Dean I, Tuong ZK, Gaspal F, Li Z, Willis C, Hasegawa T, Whiteside SK, Posner DA, Carlesso G, Hammond SA, Dovedi SJ, Roychoudhuri R, Withers DR, Clatworthy MR. Tumour-retained activated CCR7+ dendritic cells are heterogeneous and regulate local anti-tumour cytolytic activity. Nat Commun. 2024 Jan 24;15(1):682. doi: 10.1038/s41467-024-44787-1.

Li Z, Tuong ZK, Dean I, Willis C, Gaspal F, Fiancette R, Idris S, Kennedy B, Ferdinand JR, Peñalver A, Cabantous M, Murtuza Baker S, Fry JW, Carlesso G, Hammond SA, Dovedi SJ, Hepworth MR, Clatworthy MR, Withers DR. In vivo labeling reveals continuous trafficking of TCF-1+ T cells between tumor and lymphoid tissue. J Exp Med. 2022 Jun 6;219(6):e20210749. doi: 10.1084/jem.20210749.

Davidson S, Simone D, Jansen K, Cowan M, Machado C, Reekie I, Bhalla A, Borst R, Prada Medina C, Bull J, Wong ZY, Hill S, Garvilles M, Pledger S, Nisa PR, Schwingen NR, Windell D, Attar M, Disney C, Bodey AJ, Parmenter A, Byrne H, Ahmed S, Marathe S, Lee PD, Mahony C, Croft AP, Sansom S, Coles MC, Buckley CD. The embryonic origins of site-specific arthritis. Nat Immunol. 2026 Jul;27(7):1390-1403. doi: 10.1038/s41590-026-02542-2.

Cowan MJB, Davidson S, Coles M, Buckley CD. The Role of Fibroblasts Across Inflammation and Immunity. Annu Rev Pathol. 2026 Jan;21(1):423-445. doi: 10.1146/annurev-pathmechdis-080624-105114.

THEMES

Immunotherapies, Inflammation & Immunology, interacting systems, systems biology

CONTACT INFORMATION OF ALL SUPERVISORS

Mark Coles 

David Withers

Christopher Buckley