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tophat and pptx questions
what are mesenchymal cells?
small, spindle-shaped cells with large nuclei, prominent nucleoli, and fine chromatin
what type of cell (multipotent, pluripotent, unipotent, totipotent) are mesenchymal stem cells?
multipotent - differentiate as progenitor cells for all types of ct, such as fibroblasts and osteoblasts
what do mesenchymal cells produce?
extracellular matrix (ECM) that consists of ground substance
what composes the mesenchyme?
mesenchymal cells and ECM
what is mesenchyme?
type of embryonic CT that gives rise to all other CT of the body during development
where do mesenchymal cells originate from?
the mesoderm germ layer
which statement is incorrect about mesenchymal cells?
A. mesenchymal cells are small, spindle-shaped cells
B. mesenchymal cells produce ECM
C. mesenchymal cells are pluripotent
D. mesenchymal cells originate from the ectoderm
E. mesenchymal cells are multipotent
F. mesenchymal cells differentiate into CT such as fibroblasts
C. and D.
what is the epithelial mesenchymal transition (EMT)?
cell biological process that is required for remodeling of cells and tissues; occurs during embryogenesis, during wound healing, and during the acquisition of malignant traits by carcinoma cells
what cell type starts and ends the EMT?
epithelial to mesenchymal
select all that is true about EMT
A. EMT is a biologic process allowing a mesenchymal cell to undergo multiple biochemical changes to assume a polarized epithelial cell status
B. during embryonic development, phenotypic plasticity is afforded by an EMT
C. EMT is signaled by degradation of the basement membrane and the formation of a mesenchymal cell that can migrate away from the epithelial layer where it originated
D. the c-Myc oncogene is a “master regulator” which controls many aspects of EMT
E. cultures of growth-arrested feeder cells have been used inducing EMT
b. and c.
what is the mesenchymal epithelial transition (MET)?
reverse of EMT; mesenchymal cells convert to epithelial derivatives
what process related to cancer does EMT help with
tumor metastasis
what are neoplastic tissues
self-renewing, stem-like cells within tumors, called CSCs
what is the experimental approach of paper 3?
induce EMT in nontumorigenic, immortalized human mammary epithelial cells (HMLEs) via ectopic expression of transcription factors twist and snail (selected for via puromycin)
what are HMLEs?
not cancerous, but cells that have been changed such that they can divide indefinitely (aka “immortalized”)
what is the point at which a normal cell stops dividing?
called the Hayflick Limit/Phenomenonw
what occurs when a cell undergoes mitosis?
telomeres shorten, and will eventually stop when they reach a certain length
what cells have an exception to the Hayflick limit?
stem cells and cancer cells
cells that acquired fibroblast-like, mesenchymal appearances look like what?
spread out, spindle shaped
what is an example of an epithelial marker?
E-cadherin
what are examples of mesenchymal markers?
N-cadherin, vimentin, and fibronectin
adding TGF-beta-1 to epithelial cells was a good way to achieve what step?
inducement of EMT
CD44 and CD24 are what?
cell surface markers
what configuration of CD44 and CD24 is associated with human breast CSCs and normal mammary epithelial stem cells?
high CD44/low CD24
mesenchymal-like cells generated by EMT showed what kind of CD configuration?
CD44 high/CD24 low
e-cadherin
epithelial marker
Snail
transcription factor known to induce EMT
vimentin
mesenchymal marker
hTERT
catalytic subunit of the human telomerase (the gene that encodes the catalytic unit)
mammospheres
mammary epithelial stem cell aggregates derived from primary breast tumors (associated with cancer stem cells)
more mammospheres present in the cell is indicative of what?
stem cell character
more mammospheres are formed in cells containing which transcription factors?
snail, twist, and TGF-B-1
undergoing EMT does what to the percentage of mammospheres?
increases presence by >30 fold
how can the authors tell that the cells over expressing snail or twist have undergone EMT?
A. cells express more CD44 and less CD24 on average
B. E-cadherin is downregulated
C. Cells acquired fibroblast-like mesenchymal appearances
D. transforming growth factor beta-1 is expressed
A. B. and C.
some cells naturally express high CD44/low CD24. how did the authors distinguish between them and the EMT cells?
cells that underwent EMT expressed stem cell characteristics K18 and K8
which of the figures labelled in purple shows a CD44 high/CD24 low expression pattern?
B, C, and D
Study the figure and select the correct statements.
A. Cell population labelled A have CD44high/CD24low
B. Cell population labelled B CD44high/CD24low
C. Cell population labelled A form mammospheres better than the population labeled B
A and C
tamoxifen
drug used to induce EMT; tests if EMT conversion promotes generation of cancer stem cells (it does)
Note
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