Effect of WT1 gene silencing on the tumorigenicity of human glioblastoma multiforme cells.
OBJECTIVE
Wilms tumor 1 (WT1) is overexpressed in many human cancers, including glioblastoma multiforme (GBM). In another study, the authors showed that transient WT1 silencing increases the radiosensitivity of glioma cells. Studies of nonglioma cell lines have demonstrated that WT1 promotes cell proliferation and survival; however, this ability has not been rigorously analyzed in human GBM.


METHODS
The authors tested the efficacy of 2 sequences of short hairpin RNA (shRNA) directed against WT1 in U251MG human GBM cells and found that 1 sequence was capable of stably silencing WT1 expression. They then evaluated the effect of WT1 silencing on cellular proliferation, invasion, and in vivo tumor formation.


RESULTS
Stable WT1-shRNA expression significantly decreased the proliferation of U251MG cells in vitro as demonstrated by both an adenosine 5'-triphosphate-based viability assay and tritiated thymidine uptake. Furthermore, stable WT1 silencing caused significantly slower growth after the subcutaneous inoculation of tumor cells in the flanks of athymic nude mice and was associated with an increased latency period.


CONCLUSIONS
Data in this study provide proof of the principle that downregulation of WT1 causes decreased tumorigenicity of a GBM cell line in vitro and in vivo and suggest that WT1 is a promising target for novel molecular GBM therapies, perhaps in combination with standard treatment modalities.
Clark
Aaron J
AJ
Department of Anatomy and Neurobiology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, Virginia 23298-0631, USA.
Ware
Joy L
JL
Chen
Mike Y
MY
Graf
Martin R
MR
Van Meter
Timothy E
TE
Dos Santos
Wagner G
WG
Fillmore
Helen L
HL
Broaddus
William C
WC
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005909:Glioblastoma / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D009368:Neoplasm Transplantation; D034622:RNA Interference; D034741:RNA, Small Interfering; D013997:Time Factors; D025721:WT1 Proteins / Q000235:genetics*
D034741:RNA, Small Interfering; D025721:WT1 Proteins; D000255:Adenosine Triphosphate