Intrinsic Autofluorescent Phenotype: A Novel Biomarker to Identify and Isolate Glioma Stem-Like Cells

Although defined markers such as prominin-1 play a successful role in isolating glioma stem-like cells, their expression is susceptible to environmental alteration. Therefore, we determine the efficiency of the riboflavin-addicted autofluorescence method in isolating glioma stem-like cells. GL261 glioma stem-like cells were selected and the agent of riboflavin was added to the culture medium. Then, glioma stem-ike cells with autofluorescence were identified and isolated through flow cytometry. Subsequently, cell counting kit-8 was used to detect the proliferation of targeted cells and we developed a mouse model of xenograft to record the overall survival rate and tumor size and weight per day. Additionally, the expressions of Ki67, proliferating cell nuclear antigen and nestin in the tumor mass were explored by immunohistochemical assay. The feature of autofluorescence in glioma stem-like cells was identified and isolated by flow cytometry. The proliferation and malignancy of the autofluorescence glioma stem-like cells were stronger than glioma stem GL261 cells screened by prominin-1 labeling. Cell counting kit-8 assay demonstrated a significantly stronger proliferation of glioma stem-like cells with autofluorescence (p<0.01). In vitro, the Kaplan-Meier curve indicated mice bearing fluorescent stem cells had significantly decreased overall survival (p<0.01) and increased tumor volume (p<0.01) and weight (p<0.01). Then, the expression of Ki67, proliferating cell nuclear antigen and nestin in the tumor-derived from fluorescent stem cells was significantly increased by immunohistochemical assay (p<0.05). Intrinsic autofluorescent phenotype in glioma stem-like cells were identified and characterized and the marker was used to isolate these cells with high malignancy.