L13 metabolism of the cell

Question 1

why is cancer metabolism different?

Answer 1

increased cell proliferation- dont need external stimuli/ growth factors. cancer switches on intrinsic signals or destroys off switches

mutations in signalling pathways- dysregulated cell division. incr metabolism to adapt.

de-toxification of anti-cancer therapies= evade drugs by drug inactivation, cell death inhibition, drug target alteration, dna damage repair.

survival in inhospitable conditions- vegf secretion, angiogenesis

Question 2

why do cancer cells use the warburg effect ie. use glycolysis only during normoxia?

Answer 2

change in enzyme expression due to different signalling

changes in macromolecule requirement-

mitochondrial energy generation is irreversibly damaged=

Question 3

in pdg-pet imaging how is fdg taken up and why doesnt it exit the cell?

Answer 3

taken up by glucose transporters
phosphorylated by hexokinase= cannot leave

Question 4

explain each of the reasons for a cancer cell to use the warburg effect

Answer 4

-mitochondria damage- cannot enter tca cycle and restore nad+. enzyme mutations- succinate dehydrogenase defect= pheochromocytoma. fumarate hydratase defect= leiomyoma.

changes in signalling pathways- c-myc, p53, hif-1, pten mutations= involved in regulating glucose, rna and lipid metabolism

changes in requirement- lactate produced can also stimulate vagf production= angiogenesis, migration and invasion, proliferation