CPPS 325 - Cancer Pt 3: Cancer Stem Cells Review Questions with Answers

Cancer Stem Cell Concept Proposes the existence of a small population of cells that have enhanced capacity to seed a tumour What do those who favour existence of CSCs believe? (2) - These cells contribute to metastasis and disease recurrence - These cells confer chemotherapy What are the 4 experiments that were used to demonstrate CSCs 1A: Limited dilution and transplantation (2x10^5 cells are tumorgenic) 1B: Limited dilution and transplantation (Identifying unique cancerous markers) 2A: Lineage tracing of Epidermal Cancer stem cells 2B: Lineage tracing of Intestinal Cancer cells 1A: Limited dilution and transplantation (2x10^5 cells are tumorgenic) Demonstrate which cancer cells can seed a tumour 1) Obtain Normal cancer cells (Acute myeloid leukemia (AML) cells) 2) Create 3 dilutions - 2x10^4 - 2x10^5 - 2x10^6 3) Identify which dilutions create tumour - 2x10^4 did NOT - 2x10^5 and 2x10^6 both formed tumours 4) Use FACS to sort out CSC (by using HSC markers) - The CD34+/CD38- cells are tumorigenic (CSC) HSC Markers - CD34+ - CD38- What is the minimum dilution that has tumorigenic cells Every 1 in 2x10^5 cells are tumorigenic 1B: Limited dilution and transplantation (Identifying unique cancerous markers) Collect 2 groups of breast cancer cells and inject them into mouse skin 1) CD44+/CD24- - Induced tumours 2) CD44+/CD24+ - No tumours induced Tumour bulk the mean tumor size of target lesions at baseline 2A: Lineage tracing of Epidermal Cancer stem cells process 1) Obtain epidermal cancer stem cells (skin cancer) - Use K14+ to identify them from papilloma 2) Tag their Reporter gene with YFP 3) Inject the cancer cells into a model animal to make a new papilla 4) TAM Injection (induce the cre-flox system to express the marked reporter) What Epidermal Stem cell Marker is used to extract epidermal cancer stem cells K14+ 2A: Lineage tracing of Epidermal Cancer stem cells Results 6 days post TAM injection - There are green fluorescing epidermal cancer stem cells in the dermal papilloma region 14 Days post TAM injection - The YFP grows out into the tumour bulk as it is generated - The movement and growth of the green show that new cells were generated from the original ones Normal Stem Cells in the Epidermal Cancer stem cells experiment Normal stem cells also express YFP, so they will appear on the imaging, but they do not contribute to the papilloma