Investigating the phenotypical and functional features of circulatory neutrophils in Early Breast Cancer
File(s)
Author(s)
Ramessur, Anisha
Type
Thesis
Abstract
Neutrophils play a crucial role in fighting infections and facilitating wound healing. There is increasing evidence that neutrophils can influence breast cancer (BC) development, but it is unclear how early in the disease process this occurs and whether neutrophil involvement differs depending on the BC subtype.
I first investigated the expression of the neutrophil surface marker CD62L (leukocyte adhesion molecule which is rapidly shed on neutrophil priming or activation) since an expansion of CD62L negative neutrophils was found to be characteristic of cancer in a tumour-bearing mouse model of Early Breast Cancer (EBC). Granulocyte Colony Stimulating Factor administration after chemotherapy led to a faster recovery of circulatory neutrophil counts and restoration of CD62Lnegative neutrophil levels to that typically seen in untreated tumour-bearing mice.
I then conducted a pilot study of 44 treatment-naive patients with early breast cancer (EBC) and 44 paired healthy volunteers (HVs). Using flow cytometry of their blood samples, I showed that cancer patients had a higher proportion of circulatory neutrophils compared to HVs and there were changes in CD62L expression which varied depending on HR status of the patient’s BC.
In order to determine the reason for this, I assessed neutrophil kinase activity (n = 340 kinases) using a Pamgene kinase assay. There were changes in neutrophil kinase expression which varied depending on the HR status and HER2 status. HR positive HER2 negative patients had a strong upregulation in overall kinase activity compared to HVs. Regardless of HR status, the presence of HER2 in the patient’s BC correlated with a reduced neutrophil tyrosine kinase activity.
In vitro culture experiments showed that neutrophil lifespan in patients (regardless of BC subtype) is extended compared to HVs and this appears to be related to intrinsic neutrophil properties with a smaller synergistic effect from soluble factors within the plasma.
I first investigated the expression of the neutrophil surface marker CD62L (leukocyte adhesion molecule which is rapidly shed on neutrophil priming or activation) since an expansion of CD62L negative neutrophils was found to be characteristic of cancer in a tumour-bearing mouse model of Early Breast Cancer (EBC). Granulocyte Colony Stimulating Factor administration after chemotherapy led to a faster recovery of circulatory neutrophil counts and restoration of CD62Lnegative neutrophil levels to that typically seen in untreated tumour-bearing mice.
I then conducted a pilot study of 44 treatment-naive patients with early breast cancer (EBC) and 44 paired healthy volunteers (HVs). Using flow cytometry of their blood samples, I showed that cancer patients had a higher proportion of circulatory neutrophils compared to HVs and there were changes in CD62L expression which varied depending on HR status of the patient’s BC.
In order to determine the reason for this, I assessed neutrophil kinase activity (n = 340 kinases) using a Pamgene kinase assay. There were changes in neutrophil kinase expression which varied depending on the HR status and HER2 status. HR positive HER2 negative patients had a strong upregulation in overall kinase activity compared to HVs. Regardless of HR status, the presence of HER2 in the patient’s BC correlated with a reduced neutrophil tyrosine kinase activity.
In vitro culture experiments showed that neutrophil lifespan in patients (regardless of BC subtype) is extended compared to HVs and this appears to be related to intrinsic neutrophil properties with a smaller synergistic effect from soluble factors within the plasma.
Version
Open Access
Date Issued
2022-08
Date Awarded
2023-03
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Coombes, Raoul
Malanchi, Ilaria
Sponsor
National Institute for Health Research (Great Britain)
Medical Research Council (Great Britain)
Publisher Department
Department of Surgery & Cancer
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)