exam 4- cancer 1 Flashcards
(45 cards)
type of cancer most prominent in men & women
prostate
breast
cancer in animals & plants
cancer is leading cause of death in dogs (especially over 10 yo) and cats
- plant tumors are less frequent and are not as lethal as those in animals (then typically do not spread)
death rate from cancer in the US has declined steadily over the past 25 years, because of:
better management of cancer patients:
prevention
early diagnosis
innovative treatments
nanotechnology has made an impact on cancer
cancer is a diseased caused by a ___ division of ___ cells in part of the body
uncontrolled
abnormal
cancer could potentially arise from a…
single mutation
particularly in genes that control cell growth & division
what is cancer? internal & external
DNA damage
- internal: intermediates of metabolism (free radicals) and DNA replication errors (during mitosis)
- external: from sunlight, carcinogens, or ionizing radiation
usually DNA damage is detected by ___
checkpoints
mutation is repaired or cell undergoes apoptosis (in cancer, those checkpoints fail)
average human cell cycle time (life span) is ___
the duration of the cell cycle depends on…
24 hr
the cell type (embryonic vs. nerve cells)
describe the cell cycle checkpoints
G1 phase (interval b/w mitosis & DNA replication- the cell is metabolically active & growing)
S phase (synthesis): DNA replication takes place
G2 phase: cell growth continues, proteins are synthesized in preparation for mitosis
Mitosis: cell division
name the 3 cell cycle checkpoints
cell growth checkpoint (end of G1 phase)
DNA synthesis checkpoint (during S phase)
Mitosis checkpoint (during M phase)
what does the cell growth checkpoint check?
end of G1 phase
- checks whether the cell is big enough and has made the proper proteins for the synthesis phase
–> if not, cell goes through a resting period (G0) until it’s ready to divide
what does the DNA synthesis checkpoint check?
occurs during S phase
- checks whether DNA has been replicated correctly
- DNA damage
–> if all this is in order, cell continues on to mitosis (M)
what does the mitosis checkpoint check?
occurs during M phase
- checks whether mitosis is complete
–> if so, cell divides & then repeats
Checkpoint Kinase 2 (Chek2) is a ___ kinase involved in—
serine-threonine
DNA repair, cell cycle arrest or apoptosis in response to DNA damage (active in S, G1, or G2)
543 amino acids
what are the 2 things that exactly go wrong in cancer?
1- mutations in checkpoint kinase 2
2- loss of regulation in cell cycle
describe mutations in checkpoint kinase 2
- DNA damage trigger activation of the DNA damage checkpoint kinase ATM
- activated ATM phosphorylate p53 (TF)
- in addition, activates Chek2 and HIPK2
- p53 phosphorylated at Ser15, Ser20, and Ser46 activates proapoptotic genes and triggers apoptosis
in regulation of cell cycle, once cells have passed start, they are…
progression of cells through the division cycle is regulated by both ___ and ___ signals
committed to enter S phase
extracellular & intracellular signals
what are the external & internal signs or regulating the cell cycle
external signals = growth factor (hormones of proteins that stimulate cell proliferation), nutrients
internal signals = metabolomic state
list the 4 hallmarks of cancer
disruption of cell cycle checkpoints can cause cancer
1- uncontrolled proliferation
2- failure to undergo apoptosis
^^ benign tumors (remain confined to original location)
3- promotion of angiogenesis
4- metastasis
a ___ is a gene that has potential to cause cancer
oncogene
Mitogen-activated-protein-kinase (MAPK) cascade aka ___ pathway
Ras/Raf/MEK/ERK pathway
in MAPK cascade, Ras is part of the ___ family, its active when bound to ___
G protein family
GTP
in MAPK cascade, B-Raf is a ___ kinase, it phosphorylates the ___
serine/threonine protein kinase
OH group of the serine or threonine
in MAPK cascade, ERK activates transcription factors that lead to expression of ___
cyclin-D1
