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Identifier |
000431708 |
Title |
Study on the role of adipose tissue regulatory T cells in tumor development and response to immunotherapy |
Alternative Title |
Μελέτη του ρόλου των ρυθμιστικών Τ κυττάτων του λιπώδους ιστού στην ανάπτυξη όγκου και την απόκριση σε ανοσοθεραπεία |
Author
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Νεοφώτιστου-Θέμελη , Ελπίδα
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Thesis advisor
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Βεργίνης, Παναγιώτης
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Reviewer
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Τσατσάνης, Χρήστος
Ποντίκογλου, Χαράλαμπος
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Abstract |
Regulatory T cells (Tregs) are pivotal in maintaining peripheral tolerance and immune homeostasis.
They are recruited to the tumor microenvironment during tumor progression, facilitating its escape
from immune surveillance. They abundantly express immune checkpoint molecules, namely PD-1 and
CTLA-4, and are thus the main targets for immunotherapy treatments. Tregs within the visceral adipose
tissue (VAT) confer protective effects against metabolic dysfunction in obesity and are reprogrammed
in obesity-related inflammation. Links between obesity and cancer have already been established as
metabolic dysregulation has been correlated with increased cancer incidence, aggressive tumor
progression and adverse prognosis in human patients. On the other hand, improved responses to cancer
immunotherapy have been reported for overweight and mildly obese individuals. To date, the
mechanisms underlying this paradox remain to be elucidated.
In this master thesis, we set out to explore the role of VAT Tregs in tumor progression and the
development of anti-tumor immune responses, as well as in the responsiveness to immunotherapy. Our
results suggest that diet-induced obesity accelerates B16.F10 melanoma progression in both male and
female mice. Tumor-draining lymph nodes in obese mice display increased cellularity, though no
differences are observed in the content of T cell subpopulations. The obese tumor T cell profile implies
increased immune activity with reduced Treg over T effector ratios, though an overall decrease in the
total number of infiltrating leukocytes correlated with the notable accelerated tumor progression. In the
visceral adipose tissue there’s evidence of immune suppression, indicated by a trend for increased PD-1
levels on Tregs and CD8+ T cells alike, intensity of CTLA-4 signal on Tregs and Treg/T effector
analogy, though total CD45+ infiltration was slightly increased. We also report that, although the
described effects were more prominent in males than females, the trends were for the most part
comparable in both genders. Identification of specific molecular signatures in VAT Tregs during tumor
development and also comparisons of the transcriptome of VAT and tumor-infiltrating Tregs will shed
light in the contribution of obesity and specifically on obesity-related Tregs in cancer.
Overall, the inclusive approach of organismal immunometabolism acknowledges the innate
implications of different systems and their combined effects on health and disease. In this light,
unveiling the underlying mechanisms defining obesity and its effects on tumor responses and
immunotherapy effectiveness, as well as the possible implications of VAT Tregs in this interplay would
serve the dual purpose of providing immense clinical benefit but also propel our basic understanding of
the intricate cross-talk between immune cell populations.
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Language |
English |
Subject |
Cancer |
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Καρκίνος |
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Παχυσαρκία |
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Ρυθμιστικά Τ κύτταρα |
Issue date |
2020-08-05 |
Collection
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School/Department--School of Medicine--Department of Medicine--Post-graduate theses
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Type of Work--Post-graduate theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/2/3/3/metadata-dlib-1599043668-135587-3784.tkl
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Views |
255 |