[Research of the characterization of Bcrp1(+) HeLa cells]

To make sure whether Bcrp1 is the marker of cervical cancer stem-like cells or not by studying the characterization of Bcrp1(+) HeLa cells.

Immunofluorescence stained flow cytometry and electron microscope were used to sort and observe ultrastructures of Bcrp1(+) and Bcrp1(-) HeLa cells. Flow cytometry was used to identify the cycle and the rate of apoptosis with annexin V in two group cells. The expression of proliferating cell nuclear antigen (PCNA) and caspase-3 were tested using western blot method.

(1) There were 7.1% Bcrp1(+) cells and 92.9% Bcrp1(-)cells in HeLa cells. Bcrp1(+) HeLa cells were large in size of nuclear and nucleoli are clear, and there were rich of cytomicrosome and rough endoplasmic reticulum. After sorted and cultured for 24, 48, 72 hours, the adhesion in Bcrp1(+) cells were 72.8%, 81.1%, 80.4%, respectively. While, they were 3.3%, 18.7%, 12.6% at each time for Bcrp1(-) cells (all P < 0.05). (2) There are more S phase cells in Bcrp1(+) cells than that in Bcrp1(-) cells (54.1% vs 21.1%, P < 0.05), while the percentage of G(0)/G(1) and G(2)/M in Bcrp1(-) cells were higher than those in Bcrp1(+) cells (53.0% vs 44.4%, 25.9% vs 1.5%; all P < 0.05). The rate of apoptosis in Bcrp1(+) cells was lower than that in Bcrp1(-) cells (0.2% vs 5.3%, P < 0.05). (3) The expression of PCNA in Bcrp1(+) cells was higher than that in Bcrp1(-) cells (3140 vs 2255, P < 0.05), while the expression of caspase-3 of Bcrp1(+) cells was lower than that in Bcrp1(-) cells (1970 vs 3551, P < 0.05).

There are more vigor and ability of proliferation and lower rate of apoptosis in Bcrp1(+) HeLa cells than those in Bcrp1(-) cells, which may be some characters of cervical cancer stem cells.