cancer, stem cells and cancer stem cells

Question 1

what is a stem cell

Answer 1

a cell which can self-renew and differentiate

Question 2

define self-renewal

Answer 2

cell can divide into exact copies of itself with the exact same properties

Question 3

define differentiation

Answer 3

a permenant change in gene expression

Question 4

what is asymmetric stem cell division

Answer 4

when the cell renews and differentiates at the same time (this happens ~80% of the time)

Question 5

define totipotent

Answer 5

can make everything

Question 6

define pluripotent

Answer 6

can make all somatic cells

Question 7

define multipotent

Answer 7

can make many different cell types

Question 8

define bi-/tri- potent

Answer 8

2/3 etc. cell types

Question 9

define unipotent

Answer 9

can only differentiate into one cell type

Question 10

what is potency restricted by

Answer 10

with developmental age/tissue restriction

Question 11

what are the 2 types of stem cell

Answer 11

embryonic and adult (tissue) stem cells

Question 12

what are the characteristics of embryonic stem cells

Answer 12

• they are cultured in vitro from cells in the early embryo
• pluripotent
• immortal (indefinently self-renew)

Question 13

what are the characteristic of adult stem cells

Answer 13

• they exist in many tissues
• normally contribute to tissue maintenance
• numbers, properties and functions vary enormously

Question 14

what are the characteristics of somatic stem cells

Answer 14

• rare
• slow cell cycle (divide infrequently)
• symmetric OR asymmetric cell division
• unspecialised
• present in many adult tissues
• usually respect germ layer boundaries

Question 15

define regeneration

Answer 15

homeostasis + repair

Question 16

where are stem cells densley populated

Answer 16

in tissues with a natural turnover (skin, blood etc)

Question 17

why would you “reserve” stem cells

Answer 17

for injury repair (in muscle)

Question 18

what is special about the liver

Answer 18

it can fully regenerate (no matter how much has been removed)

Question 19

what is cancer caused by

Answer 19

mutations

Question 20

what are somatic cells known for

Answer 20

being often short-lived and post-mitotic, because of their specialised function

Question 21

what happens to mutations in long-lived, proliferating cells

Answer 21

they may accumulate - if a mutation occurs in a stem cellm all lineage from that stem cell will regenerate

Question 22

what do stem cells divide to make

Answer 22

progenitor cells
(which have a much more rapid cell cycle, and so they expand their no. so that the stem cells that divide infrequently can lead to the maintenance of the many cell types it maintains)

Question 23

what is the pathway from stem cell to specialised cell

Answer 23

stem cell - progenitor cell - transient amplifying cell - specialised cell

Question 24

what happens when mutated stem cells divide

Answer 24

the daughter cells are also mutated

Question 25

what are the repercussions of cancers enabling mutations

Answer 25

• increased proliferation rate
• decreased differentiation ability
• lose control
• increase invasion metastasis

Question 26

what is a cancer stem cell

Answer 26

a cancer cell with stem cell properties
they are to cancer what the somatic stem cell is to the organ

Question 27

are all tumour cells tumourigenic

Answer 27

no

Question 28

teratocarcinoma cells can form

Answer 28

chimeras