Figure 5
LBL21 suppressed CSCs in vitro and tumor formation in vivo. (a) A549 cells were incubated with LBL21 or PEITC for 24 h at indicated concentrations, and then SP cells were quantified by flow cytometry analysis. SP cells appeared as a dim tail with low red and blue Hoechst signals because of active efflux of the dye Hoechst 33342 (framed). Inhibition of the efflux pump by verapamil (Vera) led to cellular accumulation of Hoechst 33342, and SP sub-population disappeared. (b) mRNA expression levels of CSC biomarkers. A549 cells with different treatments for 24 h were analyzed via real-time qPCR. Bars means±S.D. *P<0.05, **P<0.01 versus control, n=3. (c) A549 cells were pretreated with 10 μM PEITC or LBL21 for 24 h. Then the cells were washed and cultured in fresh medium for another 48 h to allow cell death occur. Equal viable cells were inoculated subcutaneously into the flanks of athymic mice using 1.5 × 105 or 0.75 × 105 cells per injection site. The mice were monitored for tumor incidence. (d) Images of tumors from representative mice in each group. (e) Measurement of tumor volume was carried out on the indicated days. Bars means±S.D.
