extracellular vesicles Flashcards
(17 cards)
What are the main types of extracellular vesicles (EVs)?
Exosomes, microvesicles (incl. ectosomes, microparticles, oncosomes), migrosomes.
Where do exosomes originate from?
From multivesicular endosomes (MVEs).
Where do microvesicles originate from?
They bud directly from the plasma membrane.
What are migrosomes?
Vesicles structurally similar to MVBs, deposited on cell projections, can be taken up by other cells.
What is the ESCRT complex and its role in EVs?
A protein complex involved in intraluminal vesicle (ILV) formation inside MVEs; once thought to be a reliable exosome marker.
What happens when an MVB fuses with the plasma membrane?
It releases exosomes (ILVs) into the extracellular space.
Name some exogenous factors that affect EV secretion and cargo.
Hypoxia, radiation, thermal/oxidative/metabolic stress, growth factors, cell contact.
How do tumour-derived EVs affect T cells?
They suppress proliferation and can induce regulatory T cell-mediated cell death.
How do dendritic cell (DC)-derived exosomes impact the immune system?
They activate CD4+ and CD8+ T cells, and are used in cancer immunotherapy.
How do EVs remodel the tumour stroma?
They convert fibroblasts into myofibroblasts and promote angiogenesis.
How do hypoxic EVs promote angiogenesis?
By carrying pro-angiogenic factors like IL-8 and VEGF.
What role do exosomal integrins play in metastasis?
They determine organ-specific targeting (organotropism) of cancer cells.
How can EVs confer drug resistance?
Drug-resistant cells can transfer MDR traits to sensitive cells via EVs.
How might EVs interfere with antibody therapies?
By acting as decoys that sequester monoclonal antibodies.
Why are EVs promising biomarkers in cancer?
They carry tumour-specific molecular cargo that can be sampled from biofluids.
What are the challenges in using EVs as biomarkers?
Difficulty isolating pure EVs, platform variability, and need for robust assays.
Name 3 methods for EV isolation.
Affinity-based (beads, columns), chromatography, precipitation, filtration.
