10 tumour microenvironment Flashcards
(76 cards)
What is the tumour microenvironment (TME)?
he ecosystem surrounding a tumour, consisting of tumour cells, non-tumour cells, and extracellular components.
What are the three main components of the TME?
Tumour cells, non-tumour cells, and the extracellular matrix (ECM).
How does the TME support tumour growth?
It provides nutrients, survival signals, promotes immune evasion, and facilitates metastasis.
What are five key characteristics of tumour cells?
Uncontrolled proliferation, genetic instability, immune evasion, invasion/metastasis, and therapy resistance.
How do tumour cells evade the immune system?
By downregulating MHC I, secreting immunosuppressive factors, and recruiting pro-tumour immune cells.
What is the extracellular matrix (ECM)?
A network of proteins like collagen and elastin that provides structural support and stores growth factors.
How does the ECM contribute to tumour growth?
By providing a scaffold for tumour expansion, storing pro-growth signals, and influencing cell behaviour.
What are the major types of non-tumour cells in the TME?
Immune cells, stromal cells, and vascular cells.
Name three types of stromal cells found in the TME.
Cancer-associated fibroblasts (CAFs), adipocytes, and pericytes.
Name three types of vascular cells in the TME.
Endothelial cells, lymphatic cells, and pericytes.
What is the role of endothelial cells in the TME?
They support angiogenesis, create abnormal vasculature, and modulate immune responses.
How do endothelial cells influence metastasis?
By forming new blood vessels that allow tumour cells to enter circulation.
What are cancer-associated fibroblasts (CAFs)?
Fibroblasts that remodel the ECM, secrete growth factors, and promote tumour invasion.
How do CAFs contribute to therapy resistance?
By modifying the ECM, secreting protective signals, and suppressing immune responses.
What are the two main categories of immune cells in the TME?
Anti-tumour (good) and pro-tumour (bad) immune cells.
Name two key anti-tumour immune cells.
CD8+ T cells (cytotoxic T cells) and natural killer (NK) cells.
Name two key pro-tumour immune cells.
Neutrophils (PMN-MDSCs) and T regulatory cells (Tregs).
How do CD8+ T cells kill tumour cells?
By releasing perforin and granzymes or activating death receptors (FasL, TRAIL).
Why are CD8+ T cells important for immunotherapy?
They are major targets of immune checkpoint inhibitors that enhance anti-tumour immunity.
How do NK cells differ from CD8+ T cells?
NK cells kill independently of MHC I, making them effective against tumours that downregulate MHC I.
How do neutrophils (PMN-MDSCs) promote tumour growth?
By producing ROS and arginase-1, which suppress T cell activity, and by promoting angiogenesis.
How do T regulatory cells (Tregs) suppress immune responses?
Through immune checkpoints (direct suppression) and cytokine release (indirect suppression).
Why is the composition of the TME important?
It influences tumour progression, metastasis, response to therapy, and immune activity.
What is the difference between immune hot and cold tumours?
Immune hot tumours have active immune responses, while cold tumours lack immune infiltration.