摘要
malignancy and recurrence in glioblastoma multiforme.Hypoxic regions within the tumor microenvironment help maintain and promote the proliferation of CSCs.Here,we explored the effects of silencing hypoxia inducible factor-2α(HIF-2α)because of its specificity for CSCs within the hypoxic environment.Methods:Cancer stem cell neurospheres were formed by enriching from both the glioblastoma cell line U87 and from brain tumor stem cells isolated directly from human brain tumors.Silencing of human HIF-2αwas performed using both commercial and in-house transfection of a validated short interfering RNA,with all results compared to an established non-silencing control short interfering RNA.Silencing of HIF-2αwas established by Western blotting,and phenotypic effects were assayed by cell migration assays,cell viability measurements,and immunofluorescence staining of differentiation markers.Results:Transfection with either our previously reported pH-sensitive,cationic amphiphilic macromolecule-based delivery system or Lipofectamine was similarly effective in silencing HIF-2α.The chemotherapeutic resistance and neurosphere formation were reduced when HIF-2αwas silenced.Migratory capacities in the presence of macrophage conditioned media were modulated.HIF-2αsilencing was complementary to temozolomide treatment in producing phenotypic rather than cytotoxic effects.Conclusion:HIF-2αsilencing under hypoxia inhibited CSC phenotypes while promoting differentiated cell phenotypes and is complementary to existing DNA alkylating treatments in inhibiting glioma CSC activity.
基金
This work was supported by a grant from the National Institutes of Health(2R01 EB008278-07).
