lecture 18 (cancer) Flashcards
cancer cells can:
multiply in the absence of growth factor and resist against signal that induce cell death (apoptosis)
Metastasis is:
when the cancer cell invade the surrounding tissues and supplies blood vessel
what are some general properties of cancer cell?
- controls the growth signals without exterior help
- insenstive to antigrowth signals
- resist death of cell
- supplies angiogenis (blood vessel to feed)
- limitless in division
- invades tissues (metastasis)
where does the cancer cell orginate from?
rapidly dividing cells (proliferating)
True or False: it is rare to induce cancer cells in non-dividing cells.
TRUE
Mutation in ________ can give rise to cancer
Adult Stem cells
what is an example of cancer arised from haematopeiotic stem cell?
leukemia
how many types of protein that participate in controlling cell growth and division?
7 types
what is proto-oncogen?
A gene involved in normal cell growth that encode proteins that promote cell proliferation
True or False: Mutation in one copy of proto-oncogene (1 allele) is not enough to induce cancer cells.
False, it is enough to turn it to oncogene
Tumor suppressive gene:
is a gene that encodes proteins that acts to regulate cell division, keeping it in check.
care taker genes:
is a type of tumer supresser gene that repair damaged DNA
what is the difference between loss of function mutation and gain of function mutation?
Loss-of-function mutations result in an inactive or less active protein (two alleles needs to be mutant), whereas gain-of-function mutations lead to a more active protein or gain of a different function (one allele is enough for mutation).
what are the two important region of threatend mutation for cancer?
- growth factor receptor inducing a gain of function mutation leading it to work all the time
- loss of function mutation in E2F a transcripition factors
what is the type of mutation that occurs to proto-oncogen to convert them into oncogenes causing cancer?
gain of function mutation
what are the four mechanism that can produce oncogens?
1) point mutation in proto-oncogen which result in hyperactive protein production
2) chromosomal translocation of fusion of two gens to produce hybrid protein which is more active
3) chromosomal translocation that puts a diiferent promoter in control of the proto-oncogen which cause high production of proto-oncogens
4) the increase in DNA segemant containing proto-oncogen to increase the production of it (too much alleles)
how can viruses cause cancer?
viruses can insert oncogenes by accaccumulating the host gene
why can viruses accumulate the host DNA?
because it doesnt have repair enzymes
types of protein induced from tumour suppressor genes:
1) Rb: to prevent excessive cell growth by inhibiting cell cycle progression until a cell is ready to divide.
2) p16: slows cell division by slowing the progression of the cell cycle from the G1 phase to the S phase
3) p53: arrest the cell cycle if the DNA is damaged
True or False: in tumour supperssive genes one allele mutation is enough to cause cancer asssuming cancer is caused by single mutation.
False, two alleles
proteins that promotes apoptosis:
1) caretaker genes ( enzymes that participate in DNA repair)
2) Rb tumor suppressor gene
3) APC gene
4) BRACA-1 (when mutated causes brest cancer)
True or False: more than one mutation is needed to develop cancer
true
what does a mutation in APC tumour suppressor gene cause?
it makes the gene unstable and cause teh cell to divide and create a mass
proteins that are classified as proto-oncogens are:
1) cyclin E
2) E2F
3) receptors
what type of mutation is found in tumor suppressor gene??
loss of function mutation
function of p53:
it acts as a check point that arrest the cell cycle if DNA is damaged
How does mutation in p53 cause cancer?
P53 gene mutations change single amino acids, which impair the protein’s function. cell proliferation is not regulated effectively and DNA damage can accumulate in cells.
3T3 is a cell line which has a mutation in:
p53
