aft tumors in nude mice. Of particular interest, survival of the non-stem glioma cells was not dependent on sustained expression of c-Myc. In a number of recent studies in other cancer models, targeting c-Myc expression impaired cellular proliferation and induced senescence. These models may represent outcome of loss of c-Myc in more homogeneous cancer cell populations, particularly genetically engineered models driven by overexpression of c-Myc. Our study has important implications as targeting c-Myc has unique benefits specific to cellular compartments in models representing cellular heterogeneity. Although targeting c-Myc was sufficient to prevent tumor growth in our studies, the dichotomous effects of c-Myc inhibition that we have detected may support the need to simultaneously target the non-stem cell tumor populations to achieve clinical efficacy. Thus, c-Myc as a molecular target must be approached with sophistication as the majority of tumor cells may demonstrate limited therapeutic responses but a critical tumor population the cancer stem cells may be inhibited or killed to improve overall tumor control and decrease resistance to other therapies. Taken together, our study suggests that the proliferation, growth, and survival of glioma cancer stem cells are critically dependent on c-Myc expression and that targeting c-Myc pathways may significantly improve brain tumor therapy. Myc Regulates Cancer Stem Cell Materials and Methods Cell isolation and culture Primary glioma surgical biopsy specimens 20171952 were obtained from patients undergoing resection for newly diagnosed or recurrent glioma in accordance with protocols approved by the Duke University Medical Center Institutional Review Board. Written consent to utilize excess tissue for research was obtained from each patient, and de-identified tissues were used for all studies. Cells were isolated from human glioma surgical specimens and cultured as previously described. Briefly, tumors were dissected, washed in Earle’s balanced salt solution, digested with papain, titurated, and filtered. Red blood cells were lysed in diluted phosphate buffered saline solution. Glioma cells were then cultured overnight 10980276 in stem cell media at 20 ng/ml) prior to cell sorting for recovery of cellular surface antigens. The CD1332 and CD133+ fractions were separated by magnetic sorting using the CD133 Microbead kit. CD1332 cells were maintained in Dulbecco’s modified Eagle’s medium with 10% fetal bovine serum, but were cultured in stem cell media at least 24 hours prior to experiments to control differences in cell media. T3359, T3832, T4302 and T4597 were originally derived from human glioma surgical biopsy specimens and were maintained as subcutaneous xenografts in athymic BALB/c nude mice. Antibodies The antibodies used were as follows: Mouse anti-c-Myc antibody, FITC-conjugated rabbit anti-c-Myc antibody, mouse anti-cyclin D1 antibody, rabbit anti-cyclin D2 antibody, mouse anti-cyclin E antibody, mouse anti-p53 antibody were from Santa Cruz Biotechnology; APC-conjugated mouse anti-CD133 antibody was from Miltenyi; goat anti-Olig2 antibody was from R&D Systems; mouse anti-p21WAF1/CIP1 antibody was from Cell signaling Technology; mouse 503468-95-9 cost anti-actin antibody was from Millipore. Immunofluorescent staining Freshly frozen human glioma surgical biopsy samples were processed and 
10 micron sections were mounted on glass slides in accordance with the Duke University Medical Center Institutional Myc Regulates Cancer
