Persistence of CD133⁺Cells in Human and Mouse Glioma Cell Lines: Detailed Characterization of GL261 Glioma Cells with Cancer Stem Cell-Like Properties

Abstract

The concept of cancer stem cells suggests that there are malignant stem-like cells within a tumor that are responsible for tumor renewal and resistance to cytotoxic therapies. Studies have identified glioma stem-like cells that extrude Hoechst 33342 dye, representing a double-negative "side population" (SP) thought to be selectively resistant to drug therapy. A CD133+ stem cell-like subpopulation has been isolated from a human glioma that was enriched for tumor-initiating cells. It is unknown whether CD133+ cells with similar phenotype persist in established glioma cell lines, or if CD133 is a marker of glioma stem-like cells in rodents. We investigated whether CD133+ and SP cells existed in the GL261 cell line, a syngeneic mouse glioma model that is widely used for preclinical and translational research. Intracerebral injection of less than 100 CD133+ GL261 cells formed tumors, whereas it required 10,000 CD133(-) cells to initiate a tumor. CD133+ GL261 cells expressed nestin, formed tumor spheres with high frequency, and differentiated into glial and neuronal-like cells. Similar to GL261, seven human glioma cell lines analyzed also contained a rare CD133+ population. Surprisingly, we found that CD133+ GL261 cells did not reside in the SP, nor did the majority ( approximately 94%) of CD133+ human glioma cells. These results demonstrate that the expression of CD133 in murine glioma cells is associated with enhanced tumorigenicity and a stem-like phenotype. This study also reveals a previously unrecognized level of heterogeneity in glioma cell lines, exposing several populations of cells that have characteristics of cancer stem cells.

Inhibition of Sonic Hedgehog and Notch Pathways Enhances Sensitivity of CD133+ Glioma Stem Cells to Temozolomide Therapy

“…To investigate the presence of CD133 + cells in different GBM samples as well as in the cell line U87MG, we used FACS analysis as described earlier (29,30). As previously reported (30), our experiments showed that the population of CD133 + cells was a small fraction of the whole cell pool, with 0.02% in the U87MG cell line, and an average of 2.51% (standard error ± 2.12%) for the primary GBM specimens (Table 1). These glioma specimens were then sorted based on CD133 expression, and an average of 68.4% (standard error ± 5.25%) of the resultant population was positive for this marker ( Figure 1A).…”

Nanog signaling in cancer promotes stem-like phenotype and immune evasion

“…CSCs are commonly spared and thus enriched by conventional forms of cancer therapy, such as radiation or pharmacologic agents (22)(23)(24)(25). However, the relationship between CSCs and the host immune system is largely unknown.…”

The biological characteristics of glioma stem cells in human glioma cell line SHG44

“…CD133 is now extensively used as a surface marker to identify and isolate CSCs in malignant brain tumors as well as established cell lines (40)(41)(42)(43). Although widely used, the validity of CD133 was debated, as recent data revealed that CD133 + and CD133 -cells shared similar stemness and tumorigenic properties in glioma (44)(45)(46).…”