3 - chemotherapy Flashcards
what are the 5 stages of the cell cycle
G1 S G2 M G0 (quiescent)
where are the checkpoints in the cell cycle
G1 and G2 (ready for synthesis and ready for mitosis)
what are the two types of genes that regulate the cell cycle
tumor suppressor genes and oncogenes
what are the 3 main roles of tumor suppressor genes
inhibit cell division
initiate apoptosis following irreversible DNA damage
DNA repair proteins
what is p53
tumor supressor protein that regulates cell cycle
mutated in 50% of all tumors
what are proto-oncogenes
normal genes involved cell growth and proliferation, or
inhibit apoptosis
what are point mutations
small scale deletions or insertions
what are chromosomal translocations
when two separate chromosomal regions become abnormally fused
what is a Philadelphia chromosome (structure)
chromosome 22 with BCR gene fused to 9 with ABL 1 gene (makes tyrosine kinase)
what happens when you have a Philadelphia chromosome
unregulated expression of protein tyrosine kinase activity leading to unregulated cell cycle and division
found in leukaemia cancer cells
what kind of mutations and how many are needed to make cancer
multiple oncogenes and mutated tumor suppressor genes
which phases are tumor cells more susceptible to anti cancer drugs and why
S and M because they have more proliferating cells
what do pyrimidine analogyes do
compete with pyrimidine precursors for the enzyme thymidylate synthase (TS)
what is thymidylate synthase (TS) required for
the converson of dUMP to dTMP
what is 5-fluorouracil
a pyrimidine analogue
5-FU
is 5-fluorouracil active in its parent form
no
needs to become the active metabolite FdUMP
what is 6-mercaptopurine
purine analogue
inhibits purine nucleotide biosynthesis
how do purine analogues work
inhibit phophoribosyl pyrophosphate amidotransferase
rate limiting factor for purine synthesis
what are alkylating agents
highly reactive compounds which covalently link to chemicl groups commonly found in nucleic acids (amine, phosphates, sulfhydryl, OH)
what do alkylating agents cause
cross linking between strands of DNA and strand breakage