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60 Cards in this Set

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The Myc family of transcription factors is involved in ______________ ?
cell growth and differentiation
AP-1 proteins form (homodimers/heterodimers) which form (leucine zippers/alpha turn helices) and regulate (cell growth/cell motility)?
heterodimers; leucine zippers; cell growth
Name the two most commonly cited tumor suppressor genes.
p53 and Rb
T or F: Tumor suppressor genes up-regulate cell division.
FALSE!!!
p53 and Rb work by (binding transcription factors/binding DNA)
binding DNA
What is a mitogen?
compounds which stimulate cell division
T or F: DAG and TPA are mitogenic.
True
Fos and Myc can be stimulated by mitogens. What is the result of this stimulation?
Cells are reprogrammed for cell growth and division.
T or F: Cancer cells often rely on Fos and Myc in order to ramp up cell growth and division.
True
T or F: Antisense RNA technology can be used to inhibit cancers.
True, these bind to RNA transcripts of oncogenes and inhibit them from being translated.
Which oncogene is transcribed quicker after mitogenic stimulation, c-fos or c-myc?
c-fos (peak at less than 2 hours), peak for c-myc is around 5 hours post-stimulation
Why is myc so active in Burkitt's lymphoma?
translocation
Why does translocation often active proto-oncogenes to oncogenes?
Loss of regulatory sites upstream of gene
In Burkitt's lymphoma, c-myc oncogene is now regulated by what kind of regulator sites?
Immunoglobulin regulatory sites which are very active = oncogene
In Burkitt's lymphoma, myc loses an exon, which one?
exon 1
In Burkitt's lymphoma, what tell of cell grows uncontrollably?
B-cell
Estrogen receptors are also________
transcription factors (like all steroid receptors)
Estrogen receptors are (on the cell surface membrane/in the cytoplasm)
in the cytoplasm
What happens to estrogen receptors after binding their ligand?
They dimerize and go the nucleus where they act as transcription factors (bind DNA via zinc fingers)
As breast cancer advances, the cells will become (more/less) differentiated?
less
Is early or advanced breast cancer tamoxifen sensitive?
early, advanced breast cancer is less responsive to tamoxifen
What is tamoxifen?
it binds estrogen receptors and deactivates them
T or F: tamoxifen is only used after a breast tumor is found, never before.
False, tamoxifen may be used a chemopreventative for those at high risk for breast cancer.
Estrogen, in breasts, normally stimulates the development of _______
breast epithelium
Tamoxifen bind the hormone binding site on the estrogen receptor and _________
switches the receptor to a different conformation (inactivation)
T or F: tamoxifen structure highly resembles the structure of estrogen.
False
What other drug works as well as tamoxifen but does not promote uterine cancer?
raloxifene
Mutations in tumor suppressor genes are (recessive/dominant), while mutations in proto-oncogenes are (recessive/dominant)
recessive;dominate - need 2 mutations for tumor suppressor genes to lose regulation, need only 1 mutation in proto-oncogenes to form an oncogene
Main categories of tumor suppressor genes include: (3)
1.transcription factors
2. cell adhesion molecules
3. signal transduction effectors
Examples of tumor suppressor transcriptions factors include:
p53, WT1 (Wilms) and RB1 (retinoblastoma)
Examples of cell adhesion tumor suppressors:
DCC
Examples of signal transduction effector tumor suppressors:
NF1-Ras GTPase
Important tumor suppressor, whose mutation can result in breast cancer
brca1
Mutated forms of brca1 are found in the nucleus or cytoplasm?
cytoplasm
RB1 causes pediatric tumors in what structure?
the eye
RB1 protein binds to which transcription factor to inhibit its action?
E2F
E2F is responsible for:
transition into the S-phase of the cell cycle
In order for retinoblastoma to develop, is one mutated allele sufficient?
No, both alleles must be mutated
T or F: mutations in rb1 are responsible only for mutations of the eye?
Fasle, they are responsible for pediatric cancers of the eye, but mutated forms of this gene are also present in a wide variety of adult cancers including breast, lung and pancreas
Mutations in rb1 can inlcude (6):
point, gene conversion, deletion, mitotic recombination, chromosomal loss and duplication, monosomy (chromosomal loss)
T or F: Wilms tumors are pediatric lung tumors.
False, they are pediatric kidney tumors
The DNA binding domain of the Wilms tumor suppressor gene consists of four _______________.
Cys 2 His 2 TFIIIA type zinc fingers
When mutated, which of the 4 DNA binding domains is lost?
number 3 - loss of norman DNA binding specificity
What compound in tobacco smoke causes mutations in p53?
benzopyrene
Benzopyrene has what structure?
polycyclic aromatic hydrocarbons
T or F: Benzypyrene itself causes mutations.
False, benzypyrene and other PAHs are not carcinogenic, but their oxidized detoxification products are
benzypyrene is "detoxified" to _______
diol-epoxide, which is actually highly reactive
diol-epoxide causes what type of mutation?
G-T transversion
p53 mutations are (generally random/concentrated in hotspots)?
concentrated in hotspots
p53 binds DNA via ____________ which have 3 ______ residues and 1____ residue?
zinc fingers; Cys; His
Mutations in p53 will result in what consequence in the cell?
Loss of p53 binding to DNA and loss of tumor suppression.
Aggrecan is a protein in the _______
ECM
Aggrecanase function is:
degradation of aggrecan
Others proteins which degrade aggrecan are called_____________
MMPs
The proteinase domain of aggrecanase consists of __________?
zinc coordinated by three histidine residues
Cancer and arthritis are (dependent on/independent of) degradation of aggrecan and the ECM?
dependent on
Inhibitors of aggrecanase could possibly help in which two diseases?
cancer and arthritis
Elastase may be responsible for ____________?
degeneration of lung tissue in emphysema
How many zinc molecules are present in elastase
2
Inhibitors of MMPs have what kind of chelators?
hydroxamic chelator