cancer hallmarks 2 Flashcards
(32 cards)
what is the 4th hallmark of cancer
infinite replicative potential
where and what are telomeres
DNA segments at ends of chromosomes, regions of repetitive nucleotide sequence at each end of the chromosome
function of telomeres
protect chromosomal integrity, tally the number of replicative generations and initiate senescence and crisis
how do telomerase enzyme complexes enable endless replication
telomerase complex restores telomeres to the end of chromosomes
is telomerase complex active or inactive in cancer and normal cells
cancer=active
normal=inactive (telomere shortens each division to reach a limit)
what is telomere reverse transcriptase (TERT) and what does it do
RNA dependent reverse transcriptase, elongates chromosome by adding TTAGGG sequences
what is telomerase made up of
hTERT=protein enzyme
hTR=RNA template
what is hTR and what does it do
human telomerase RNA
-provides template (AAUCCC) that tells enzyme what DNA sequence to add (TTAGGG)
what is hTERT and what does it do
human telomerase reverse transcriptase
-reads RNA template and adds DNA repeats to the 3’ end of chromosome
what is 5th hallmark of cancer
sustained angiogenesis
what is angiogenesis
proliferation of new capillaries/formation of new blood vessels
-can be turned on tumour cells
what is VEGF and bFGF
VEGF=vascular endothelial growth factor
bFGF=basic fibroblast growth factor
what is angiogenesis important for
-primary tumour growth (promotion of small clusters of mutated cells to large malignant growth)
-metastasis (cardiovascular system provides escape for tumour cells from primary site)
what is the 6th hallmark of cancer
tissue invasion and metastasis
two ways cancer spreads through body
invasion=penetrate neighbouring tissue
metastasis=colonisation at distant sites
what is EMT and what does it do
epithelial mesenchymal transition programme
-regulates tumour invasion and metastasis
difference between benign and malignant tumours
malignant=abnormal chromosomes, poorly differentiated, frequent division, can invade and metastasise
benign=normal chromosomes, differentiated, rare division/slow growing, encapsulated
describe anchorage dependent in normal tissues
cells adhere to cells and extracellular matrix (needs attachment to a solid surface to survive/divide)
describe anchorage independent in cancer tissues
cell adhesion molecule E-cadherin is compromised or absent (can survive and proliferate without attaching to a surface)
cancer cells release MMPs, what are they and what do they do
MMP=matrix metalloproteinase
-dissolves basement membranes to allow invasion and escape
invasion of vascular beds of distant organs allow what
secondary tumours, metastasis usually to lungs/liver/bone/brain
secondary tumours are more…
aggressive and resistant to therapy
how do tumours promote inflammation
-tumours attract inflammatory cells
-inflammatory cells release ROS
-ROS damages proteins and DNA
-ROS causes mutations in cells, making them more malignant
what is ROS and what do they do
reactive oxygen species, highly reactive chemical that damages DNA and proteins
