Table 1.

p14ARF knockdown increases the camptothecin sensitivity of the cancer stem-cell-like Caco2 cells.

siRNA	% Dead CD44 Positive Cells (CPT)	% Dead CD44 Negative Cells (CPT)	Total % Dead Cells (CPT)	Total % Dead Cells (DMSO)
siRNA (scramble)	25.3	74.7	19	7
siRNA (p14ARF)	38	62	45.4	32.4

Caco2 cells were transfected with siRNA (scramble) or siRNA (p14ARF) before treatment with 0.5 μM CPT or DMSO. The cells were harvested, labeled with APC conjugated anti-CD44 antibody, stained with propidium iodide (PI), and analyzed by flow-cytometry using the Beckman Cytoflex instrument. Data were analyzed and compensated using FlowJo software. After removal of cell debris and doublets by using forward scatter (FSC), side scatter (SSC), and single stain gatings, the percentages of total dead cells were estimated by the total number of PI positive cells. The percentage of CSC-like (CD44 positive) dead cells was calculated as: number of double positive stained cells (PI positive and CD44 positive)/total number of dead cells (all the PI positive cells). The percentage of non-CSC-like (CD44 negative) dead cells was calculated as: number of single positive stained cells (PI positive and CD44 negative)/total number of dead cells (all the PI positive cells).