Pediatric brain tumor cancer stem cells: cell cycle dynamics, DNA repair, and etoposide extrusion.
Reliable model systems are needed to elucidate the role cancer stem cells (CSCs) play in pediatric brain tumor drug resistance. The majority of studies to date have focused on clinically distinct adult tumors and restricted tumor types. Here, the CSC component of 7 newly established primary pediatric cell lines (2 ependymomas, 2 medulloblastomas, 2 gliomas, and a CNS primitive neuroectodermal tumor) was thoroughly characterized. Comparison of DNA copy number with the original corresponding tumor demonstrated that genomic changes present in the original tumor, typical of that particular tumor type, were retained in culture. In each case, the CSC component was approximately 3-4-fold enriched in neurosphere culture compared with monolayer culture, and a higher capacity for multilineage differentiation was observed for neurosphere-derived cells. DNA content profiles of neurosphere-derived cells expressing the CSC marker nestin demonstrated the presence of cells in all phases of the cell cycle, indicating that not all CSCs are quiescent. Furthermore, neurosphere-derived cells demonstrated an increased resistance to etoposide compared with monolayer-derived cells, having lower initial DNA damage, potentially due to a combination of increased drug extrusion by ATP-binding cassette multidrug transporters and enhanced rates of DNA repair. Finally, orthotopic xenograft models reflecting the tumor of origin were established from these cell lines. In summary, these cell lines and the approach taken provide a robust model system that can be used to develop our understanding of the biology of CSCs in pediatric brain tumors and other cancer types and to preclinically test therapeutic agents.
Hussein
Deema
D
Children's Brain Tumour Research Centre, School of Clinical Sciences, University of Nottingham, CBTRC, D32 Medical School, QMC, Clifton Boulevard, Nottingham NG7 2UH, UK.
Punjaruk
Wiyada
W
Storer
Lisa C D
LC
Shaw
Lucy
L
Othman
Ramadhan
R
Ottoman
Ramadan
R
Peet
Andrew
A
Miller
Suzanne
S
Bandopadhyay
Gagori
G
Heath
Rachel
R
Kumari
Rajendra
R
Bowman
Karen J
KJ
Braker
Paul
P
Rahman
Ruman
R
Jones
George D D
GD
Watson
Susan
S
Lowe
James
J
Kerr
Ian D
ID
Grundy
Richard G
RG
Coyle
Beth
B
D000293:Adolescent; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D001932:Brain Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D002453:Cell Cycle; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D020552:Comet Assay; D004260:DNA Repair; D019008:Drug Resistance, Neoplasm; D005047:Etoposide / Q000494:pharmacology*; D005909:Glioblastoma / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D006801:Humans; D051379:Mice; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D014411:Neoplastic Stem Cells / Q000473:pathology* / Q000637:transplantation; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
D000972:Antineoplastic Agents, Phytogenic; D005047:Etoposide