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The Expression Profile of PD-1 and its Ligand PD-L1 in Human Monocytes and Breast Cancer

Lilja, Marie (2017) MOBN01 20162
Degree Projects in Molecular Biology
Abstract
Breast cancer is the most common type of cancer in women and there are different types of breast cancers. Although the survival among breast cancer patients has improved the last decade, there is still a large group of patients with a bad prognosis. In recent years, a new set of immunotherapies called immune checkpoint inhibitors targeting the regulatory receptors in T-cell activation and activity have emerged as a new treatment option. One of these checkpoint inhibitors is programmed death protein-1 (PD-1) with its ligand PD-L1. Some tumours have highjacked this finely tuned homeostasis mechanism by expressing PD-L1. The aim with this project was to determine the expression of PD-1 and PD-L1 on monocytes and human breast cancer cell... (More)
Breast cancer is the most common type of cancer in women and there are different types of breast cancers. Although the survival among breast cancer patients has improved the last decade, there is still a large group of patients with a bad prognosis. In recent years, a new set of immunotherapies called immune checkpoint inhibitors targeting the regulatory receptors in T-cell activation and activity have emerged as a new treatment option. One of these checkpoint inhibitors is programmed death protein-1 (PD-1) with its ligand PD-L1. Some tumours have highjacked this finely tuned homeostasis mechanism by expressing PD-L1. The aim with this project was to determine the expression of PD-1 and PD-L1 on monocytes and human breast cancer cell lines, to investigate whether breast cancer cells may affect PD-1 or PD-L1 expression on monocytes, in a tumour microenvironment. Primary monocytes were stimulated with pro- and anti-inflammatory cytokines or cultured in breast cancer cell line conditioned media and analysed for the expression of PD-1 and PD-L1. PD-L1 expression was found on claudin-low triple negative breast cancer (TNBC) cells and on monocytes cultured in condition media from claudin-low cells. A cytokine array was evaluated to compare the cytokine secretion of TN and hormone receptor positive (HR+) breast cancer cells. TNBC cells were found to secrete more cytokines compared to HR+ cells, among the cytokines GM-CSF was detected. GM-CSF was found to induce the expression of foremost PD-L1 on monocytes. IFN-γ upregulated the expression of PD-L1 on monocytes, whereas IL-10 induced the expression of PD-1. (Less)
Popular Abstract
Immune regulators on human breast cancer cells and white blood cells

Breast cancer is the most common type of cancer in woman. Over the last decade, the survival among breast cancer patient has improved, but there is still a large group of patients with a bad prognosis. Recently a new immune therapy, immune checkpoint inhibitors, with the ability to increase the tumour specific T cell response has emerged.

Lymphocytes of the adaptive immune system can kill tumour cells, but to be able to do this they need three signals of activation. Firstly, an antigen presenting cell have to present an antigen to the T cell. Secondly, a co-receptor on the T cell have to bind to an antigen presenting cell. Lastly, a cytokine has to bind to a... (More)
Immune regulators on human breast cancer cells and white blood cells

Breast cancer is the most common type of cancer in woman. Over the last decade, the survival among breast cancer patient has improved, but there is still a large group of patients with a bad prognosis. Recently a new immune therapy, immune checkpoint inhibitors, with the ability to increase the tumour specific T cell response has emerged.

Lymphocytes of the adaptive immune system can kill tumour cells, but to be able to do this they need three signals of activation. Firstly, an antigen presenting cell have to present an antigen to the T cell. Secondly, a co-receptor on the T cell have to bind to an antigen presenting cell. Lastly, a cytokine has to bind to a cytokine receptor on the T cell. The co-receptor on the T cell can be both of an activating and an inhibiting kind and are therefore called immune checkpoints. Under normal circumstances, checkpoint inhibitors play a huge role in preventing autoimmunity, and protecting the cells and tissues from damage during infections and inflammation. One of these inhibitory receptors is programmed cell death protein-1 (PD-1) with its ligand PD-L1. Tumours and tumour infiltrating leukocytes can express PD-L1, leading to suppression of the anti-tumour T cell response. We analysed the expression of PD-1 and PD-L1 on different human breast cancer cell types and investigated if human breast cancer cells can affect the expression of PD1 and PD-L1 on human monocytes (white blood cell type).

The expression of PD-1 and PD-L1 was evaluated on 8 human breast cancer cell lines derived from different breast cancer subtypes. To determine the impact of the breast cancer cells on the expression of PD-1 and PD-L1 on monocytes, monocytes were cultured with or without media from the 8 different breast cancer cells. Monocytes were also stimulated with GM-CSF and the pro-inflammatory cytokine IFN-γ and the anti-inflammatory cytokine IL-10. Human monocytes used in this study were isolated form blood from healthy donors.

PD-L1 was foremost found to be expressed on the most aggressive subtype of breast cancer cells (triple negative), whereas PD-1 was not expressed at all. These triple negative breast cancer cells also had the highest ability to induce PD-L1 expression on monocytes by the secretion of a variety of cytokines. PD-1 was also to some extend regulated by all breast cancer cells. Furthermore, a pro-inflammatory environment was found to regulate the expression of PD-L1 on monocytes, whereas an anti-inflammatory environment regulated the expression of PD-1.

Far from everyone respond to immune checkpoint inhibitors and it is not known why. To understand why immune checkpoint inhibitor therapy only works in some individuals and to better predict which patients will respond to the therapy we need to get a better understanding of the regulatory mechanisms of PD-1 and PD-L1. In this project, I have shown that the pro-inflammatory microenvironment of TNBC is one such regulatory mechanism.

Master’s Degree Project in Biology/Molecular Biology/Medical Biology 45 credits 2017
Department of Biology, Lund University

Advisor: Karin Leandersson and Camilla Rydberg Millrud
Advisors Unit/Department: Department of Translational Medicine, Cancer Immunology (Less)
Please use this url to cite or link to this publication:
author
Lilja, Marie
supervisor
organization
course
MOBN01 20162
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
8924780
date added to LUP
2017-09-05 14:18:47
date last changed
2017-09-05 14:18:47
@misc{8924780,
  abstract     = {Breast cancer is the most common type of cancer in women and there are different types of breast cancers. Although the survival among breast cancer patients has improved the last decade, there is still a large group of patients with a bad prognosis. In recent years, a new set of immunotherapies called immune checkpoint inhibitors targeting the regulatory receptors in T-cell activation and activity have emerged as a new treatment option. One of these checkpoint inhibitors is programmed death protein-1 (PD-1) with its ligand PD-L1. Some tumours have highjacked this finely tuned homeostasis mechanism by expressing PD-L1. The aim with this project was to determine the expression of PD-1 and PD-L1 on monocytes and human breast cancer cell lines, to investigate whether breast cancer cells may affect PD-1 or PD-L1 expression on monocytes, in a tumour microenvironment. Primary monocytes were stimulated with pro- and anti-inflammatory cytokines or cultured in breast cancer cell line conditioned media and analysed for the expression of PD-1 and PD-L1. PD-L1 expression was found on claudin-low triple negative breast cancer (TNBC) cells and on monocytes cultured in condition media from claudin-low cells. A cytokine array was evaluated to compare the cytokine secretion of TN and hormone receptor positive (HR+) breast cancer cells. TNBC cells were found to secrete more cytokines compared to HR+ cells, among the cytokines GM-CSF was detected. GM-CSF was found to induce the expression of foremost PD-L1 on monocytes. IFN-γ upregulated the expression of PD-L1 on monocytes, whereas IL-10 induced the expression of PD-1.},
  author       = {Lilja, Marie},
  language     = {eng},
  note         = {Student Paper},
  title        = {The Expression Profile of PD-1 and its Ligand PD-L1 in Human Monocytes and Breast Cancer},
  year         = {2017},
}