Cancer, stem cell and cancer stem cells Flashcards
What is a stem cell?
A cell which can self-renew and differentiate
Totipotent
Can differentiate into anything
Pluripotent
Can make all somatic cells
Multipotent
Can make many different cell types
Unipotent
Can make only one cell type
What restricts potency?
development age
tissue restriction
What type of property is potency
a CELL property, not a STEM CELL property
What can a zygote give rise to?
Every cell which makes an embryo
What is a zygote?
NOT A STEM CELL
2 cell blastomere - as the cell makes new ones, the cell loses mass and becomes a new cell
What are the types of stem cells?
Embryonic stem cells
Adult stem cells
Describe embryonic stem cells
in vitro cells from early mammalian or mice blastocytes
pluripotent
immortal
Describe adult stem cells
exist in many tissues
normally contribute to tissue maintenance
number, properties and functions vary
What are the somatic stem cell characteristics?
Rare Slow cell cycle Unspecialised Usually respect germ layer boundaries Symmetric or assymetric cell division Present in many adult tissues
Regeneration
homeostasis and repair of tissues with a natural turnover e.g. blood
Reserve cells
for injury repair - muscle
somatic cell properties
short lived
post-mitotic - mature cell which is no longer able to undergo mitosis
Describe progenitor cells
able to differentiate into a specific cell type
tend to be pushed to differentiate into a specific target cell
can only divide a certain number of times
do not self-renew
What cells are commonly have cancer-causing mutations?
Progenitor cells
Stem cells
What is the normal situation for cell development?
Stem cell self renews -> progenitor cell formation -> oligolineage precursor -> mature cells
What happens to both cancerous stem cells and progenitor cells?
They stop differentiating and keep self-renewing
Teratomas
germ cell tumour - begins in cells which give rise to sperm or eggs
What are the two types of teratomas?
Mature teratomas - include dermoid cysts - usually benign
Immature teratomas - cancerous
Teteratocarcinomas
a malignant epithelial tumour arising in a teratoma
Small set of cells, small cytoplasm and a large nucleus
Embryonal carcinoma cells
If you put a teratocarcinoma into a healthy mouse it will make a brand new tumour which looks identical to the size of the original cells and it is malignant.
Cancer stem cell
A cancer cell with stem cell properties - able to self-renew and differentiate
- doesn’t have to be a stem cell which got cancer
Evidence of CSC in progenitor cells
Acute myeloid leukaemia (AML) in SCID mice
Expansion of AML-colony forming unit (CFU) but poor proliferation in vitro
Only CD34+, CD38- could, similar to haemapoietic stem cells
Most likely early progenitor cells (CD90-)
