Stem Cells And Cancer Flashcards
(23 cards)
What are stem cells ?
They are undifferentiated cells that have the ability to differentiate into specialised cells
What is totipotent ?
Cells that can differentiate into any cell type
What is pluripotent ?
Can differentiate into any body cell, apart from the placenta
What is multipotent ?
Can differentiate into specific related cell types
What is unipotent ?
Can differentiate into only one cell type
What is oligopotent ?
Can differentiate into a few cell types
What are the different types of stem cell ?
- Adult stem cells
- Embryonic stem cells
- Induced pluripotent stem cells
- Perinatal stem cells- amniotic and foetal
What are adult stem cells ?
Found in various adult tissues. Mainly in bone marrow
Mainly multipotent
Used for bone marrow transplants
What are embryonic stem cells ?
From early embryonic tissues
Used for research
What are induced pluripotent stem cells?
Adult cells reprogrammed back into a pluripotent state
For personalised medicine, disease modelling
What are perinatal stem cells ?
From amniotic fluid and umbilical chord tissue
What are uses of stem cells ?
- Transformation of plant cells- use callus tissue (undifferentiated plant cells that form when plant tissue is wounded)
- Therapeutics- stem cell transplants, bone and cartilage regeneration, organ growth
- Research- studying human development, study disease mechanisms, drug development
- Tissue engineering- regeneration of damaged tissues, skin grafts
What are cell division cycle (cdc) mutants ?
They are temperature sensitive mutants which stop at a particular point of the cell cycle
What is cdc2 ?
Cell division cycle protein 2
Cdc2 in fission yeast governs transition from G1 to S and from G2 to M. Cdk1 catalyses phosphorylation of the lamins, leading to breakdown of the nuclear envelope.
A mutant of the protein would mean that the protein cannot enter mitosis, so is stuck in G2.
What is cancer caused by ?
Unregulated proliferation of cells
Causes:
1. Genetic mutations
2. Distribution of cell cycle
3. Immune system invasion
What are tumour suppressor genes ?
They limit cell division and promote cell death.
Mutations can occur which inactive these genes, leading to cancer.
What are oncogenes ?
They encourage cell proliferation
“Gain of function” mutations
What is P53 ?
A tumour suppressor protein
It regulates the expression of genes involved in cell cycle arrest, DNA repair and senescence
Mutations can occur which cause cancer
Describe the therapies for cancer
- Surgery
- Radiotherapy- target specific tissues to kill off rapidly dividing cells
- Chemotherapy- chemical poisons to inhibit rapidly dividing cells
- Pharmaceuticals- block cell signalling and interfere will genetic control
What is the cancer stem cell hypothesis ?
Within a tumour, there is a small population of stem cells that have the ability to differentiate and drive tumour growth.
It is thought that you have to kill the stem cells to prevent the cancer from developing further, otherwise it will keep coming back.
What did Sir Martin Evans do ?
He was the first to culture embryonic stem cells
What are stem cell niches ?
Stem cell populations are established in niches.
These are specific locations that regulate participation in tissue generation, maintenance and repair.
What potency are most plant tissues ?
Totipotent
Meristems contain undifferentiated, dividing cells- roots and shoots
