Sulforaphane Suppressed Proliferation of Lung Cancer Stem Cells in vitro

Objective To investigate the effect of sulforaphane(SFN) on regulating proliferation of lung cancer stem cells and its mechanism.

Methods The effect of SFN on the proliferation of H460 cells was measured by MTT method; cell apoptosis and side population rate were analyzed by fluorescence activated cell sorting(FACS); the change of tumor sphere growth was detected by sphere formation experiment; H460 cells with low expression ofβ-catenin gene was established by shRNA lentivirus transfection, and the effect of SFN on the expression ofβ-catenin, Oct4, Sox-2, c-Myc and Nanog was examined with or withoutβ-catenin expression by Western blot.

Results SFN efficiently suppressed the proliferation of H460 cells in vitro and the IC₅₀ was 11.2μmol/L. The number of apoptotic cells was dose-dependently increased after the treatment of SFN for 72h. In tumor sphere formation experiment, SFN dose-dependently suppressed the growth of 1st and 2nd passage of tumor sphere, even in a very low dose(1.0μmol/L) of SFN. The proportion of side population cells detected by FACS was decreased as increment of SFN concentration. Western blot experiment showed that SFN dose-dependently suppressed the expression of several stemness-related genes, such asβ-catenin, Oct4, Sox2, c-Myc and Nanog, changed as well as side population, even in absence ofβ-catenin.

Conclusion SFN specially suppresses the proliferation of lung cancer stem cells viaβ-catenin signaling and several stemness-related genes, such as Oct4, Sox2, c-Myc and Nanog.