NOTCH pathway blockade depletes CD133-positive glioblastoma cells and inhibits growth of tumor neurospheres and xenografts.
Cancer stem cells (CSCs) are thought to be critical for the engraftment and long-term growth of many tumors, including glioblastoma (GBM). The cells are at least partially spared by traditional chemotherapies and radiation therapies, and finding new treatments that can target CSCs may be critical for improving patient survival. It has been shown that the NOTCH signaling pathway regulates normal stem cells in the brain, and that GBMs contain stem-like cells with higher NOTCH activity. We therefore used low-passage and established GBM-derived neurosphere cultures to examine the overall requirement for NOTCH activity, and also examined the effects on tumor cells expressing stem cell markers. NOTCH blockade by gamma-secretase inhibitors (GSIs) reduced neurosphere growth and clonogenicity in vitro, whereas expression of an active form of NOTCH2 increased tumor growth. The putative CSC markers CD133, NESTIN, BMI1, and OLIG2 were reduced following NOTCH blockade. When equal numbers of viable cells pretreated with either vehicle (dimethyl sulfoxide) or GSI were injected subcutaneously into nude mice, the former always formed tumors, whereas the latter did not. In vivo delivery of GSI by implantation of drug-impregnated polymer beads also effectively blocked tumor growth, and significantly prolonged survival, albeit in a relatively small cohort of animals. We found that NOTCH pathway inhibition appears to deplete stem-like cancer cells through reduced proliferation and increased apoptosis associated with decreased AKT and STAT3 phosphorylation. In summary, we demonstrate that NOTCH pathway blockade depletes stem-like cells in GBMs, suggesting that GSIs may be useful as chemotherapeutic reagents to target CSCs in malignant gliomas.
Fan
Xing
X
Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, Michigan 48109-2200, USA. xingf@umich.edu
Khaki
Leila
L
Zhu
Thant S
TS
Soules
Mary E
ME
Talsma
Caroline E
CE
Gul
Naheed
N
Koh
Cheryl
C
Zhang
Jiangyang
J
Li
Yue-Ming
YM
Maciaczyk
Jarek
J
Nikkhah
Guido
G
Dimeco
Francesco
F
Piccirillo
Sara
S
Vescovi
Angelo L
AL
Eberhart
Charles G
CG
D000071916:AC133 Antigen; D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D014408:Biomarkers, Tumor / Q000378:metabolism; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D005909:Glioblastoma / Q000188:drug therapy* / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D009474:Neurons / Q000187:drug effects* / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D010455:Peptides / Q000378:metabolism*; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051883:Receptor, Notch2 / Q000235:genetics / Q000378:metabolism*; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D018874:Spheroids, Cellular; D013997:Time Factors; D014162:Transfection; D047368:Tumor Burden; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
D000071916:AC133 Antigen; D015703:Antigens, CD; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D004791:Enzyme Inhibitors; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; C000606024:Prom1 protein, mouse; D051883:Receptor, Notch2; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D051057:Proto-Oncogene Proteins c-akt; D053829:Amyloid Precursor Protein Secretases