Neural crest migration Flashcards
Define metastasis in terms of cancer.
The secondary growth of cancer tumours from cells originating from the primary site. Essentially the migratory power of the cells.
Neural crest migration is similar to cancer metastasis. True or false?
True.
In experiments where human melanoma cells were grafted into the region of chick embryos where the NC cells originate from, what happened?
The melanoma cells began to behave like NC cells, following their migratory patterns and differentiating into NC cell derivatives.
What do experiments with human melanoma grafts onto chick embryos tell us about cancer cells?
Their fate is heavily influenced by their environment.
Explain the basic mechanism of NC cells migration.
Cells migrate in 4 streams in the same direction. At the borders of each stream there are inhibitory signals.
List 3 examples of inhibitory signal at the borders of NC streams.
- Ephrins
- Slit/robo
- Semaphorins
Masses of NC cells eventually migrate to different locations. Chemoattractants are responsible for this directionality. True or false?
False - there is no evidence of this.
Masses of NC cells eventually migrate to different locations. Polarisation is responsible for this directionality. True or false?
False - although the leader cells display polarity, the cells migrate as a cluster not individually.
Masses of NC cells eventually migrate to different locations. Actin polymerisation is responsible for this directionality. True or false?
True - the cells produce lamellipodia, flattened extensions used for adhesion. They extend their lamellipodia which stick to something, and then pull the rest of the cell in that direction. Actin polymerisation pushes the membrane forwards.
Why are the leader NC cells polarised?
They have more space to move and extend their lamellipodia forwards.
Define ‘contact inhibition of motion’ (CIL).
The phenomenon of a cell ceasing to move in the same direction as a result of physical contact with another cell.
In CIL, what happens to the lamellipodia when 2 cells touch?
If the lamellipodia of one cell touches another cell, it immediately collapses and moves in another direction.
What is the migration formation of NC cells like?
The initial line of cells extend the lamellipodia and move forwards, creating space for the row behind them to do the same and so forth.
If CIL is true, how is it that cells in a cluster do no separate, or if they do the lost cells always return to the main body?
All NC cells produce chemoattractants and possess the necessary complementary receptors. Thus there is co-attraction between cells in a cluster.
Modelling experiments have shown that only cells that exhibit CIL and produce chemoattractants move in a unidirectional cluster. True or false?
True.
