Stem Cells

Question 1

Niche

Answer 1

Microenvironment.
Niche can help stem cells differentiate or self-renew or maintain differentiation (in adult life this can happen with injury etc.). There is important talk b/w stem cells w/ each other, their neighbors, and many signals like ATP.

Question 2

Adult stem cells

Answer 2

Probably not as static as we previously thought, may be plastic.
Seen in experiment with mice and bone marrow transplants (in response to injury more stem cells recruited to epithelia), and ability to trans-differentiate thymus cells.

Question 3

How do you make iPS?

Answer 3

Take biopsy, culture cells, pull out fibroblasts, give trx factors, wait and pick out stem cells!

Question 4

Stem cells in cancer

Answer 4

Most cancers are of epithelial origin (breast, cancer, lung etc.).
Stem cells are only ones that permanently live in epithelium.
If you treat just rapidly dividing cells, relapse can happen b/c of those cancerous stem cells left behind.
drug example: cyclopamine. against hedge hog pathway.