Biological and clinical implications of the non-small cell lung cancer immune contexture

: an investigation of the tumour microenvironment

Abstract

Despite revolutionary advances in lung cancer therapy, survival outcomes for non-small cell lung cancer remain poor. The cellular composition of the tumour microenvironment is recognised as a key determinant of tumour biology, determining disease prognosis, progression and therapeutic response. The immune cell contexture (cell type, density and spatial location) of the tumour microenvironment (TME) influences the outcome of such interactions, as each factor determines the functionality of immune cells. Immunosuppressive cells, damage‐associated molecular patterns (DAMPs), as well as factors which can affect DAMPs release including reactive oxygen species are proposed to govern immune contexture by either impeding or activating the antitumour response respectively. Existing chemotherapies are known to induce immunogenic cell death in vitro, turning immunologically ‘cold’ tumours ‘hot’. The potential for DAMPs and other factors to govern the immune cell contexture of NSCLC patients remains to be explored.

Stress response protein expression, tumour and immune cell morphology and populations were analysed in samples from 162 chemotherapy-naïve NSCLC adenocarcinoma patients (stage I-IIA). In a sub-cohort (n=60), multiplex immunofluorescence (mIF) was performed utilising lymphocytes, DAMPs and myeloid-derived suppressor cell (MDSC) panels. Infiltration and spatial analyses were performed using HALO® software. NUC-3373, a phosphoramidate transformation of the existing chemotherapy 5-fluorouracil, mediated DAMPs release, immunogenic cell death potentiation and MDSC immunosuppressive mechanisms were investigated in monoculture and co-cultures of cancer cells and immune cells. Stress response protein expression found numerous novel observations in both tumour and immune cells within the TME. Longer overall survival (OS) was demonstrated in the immune-high vs -low patients (HR, 1.763; 95% CI, 1.098-2.830, *p = 0.03). mIF showed the majority of CD8+ cytotoxic T cells and CD20+ B cells were found in DAMPs^high areas, demonstrating positive association between calreticulin expression and CD8+ cytotoxic T cell spatial distribution. MDSC-mediated mechanisms of immunosuppression and negative association with OS (HR, 0.5456; 95% CI, 0.2355-1.265, *p= 0.04) were elucidated using bioimage analysis. NUC-3373 demonstrated multiple pro-immune effects upon biological processes, inducing DAMPs release, upregulating cell surface PD-L1, potentiating ICD and depleting MDSCs. These findings show the importance of immune contexture, its potential to affect cancer treatment strategy and the clinical translatability of tumour microenvironment analysis.

Date of Award	16 Jun 2023
Original language	English
Awarding Institution	University of St Andrews
Supervisor	David Harrison (Supervisor)