Glioblastoma stem cell differentiation into endothelial cells evidenced through live-cell imaging.
BACKGROUND
Glioblastoma cell-initiated vascularization is an alternative angiogenesis called vasculogenic mimicry. However, current knowledge on the mechanism of de novo vessel formation from glioblastoma stem cells (GSCs) is limited.


METHODS
Sixty-four glioblastoma samples from patients and 10 fluorescent glioma xenograft samples were examined by immunofluorescence staining for endothelial marker (CD34 and CD31) and glial cell marker (glial fibrillary acidic protein [GFAP]) expression. GSCs were then isolated from human glioblastoma tissue and CD133+/Sox2+ red fluorescent protein-containing (RFP)-GSC-1 cells were established. The ability of these cells to form vascular structures was examined by live-cell imaging of 3D cultures.


RESULTS
CD34-GFAP or CD31-GFAP coexpressing glioblastoma-derived endothelial cells (GDEC) were found in 30 of 64 (46.9%) of clinical glioblastoma samples. In those 30 samples, GDEC were found to form vessel structures in 21 (70%) samples. Among 21 samples with GDEC vessels, the CD34+ GDEC vessels and CD31+ GDEC vessels accounted for about 14.16% and 18.08% of total vessels, respectively. In the xenograft samples, CD34+ GDEC were found in 7 out of 10 mice, and 4 out of 7 mice had CD34+ GDEC vessels. CD31+ GDEC were also found in 7 mice, and 4 mice had CD31+ GDEC vessels (10 mice in total). Through live-cell imaging, we observed gradual CD34 expression when cultured with vascular endothelial growth factor in some glioma cells, and a dynamic increase in endothelial marker expression in RFP-GSC-1 in vitro was recorded. Cells expressed CD34 (9.46%) after 6 hours in culture.


CONCLUSIONS
The results demonstrated that GSCs may differentiate into endothelial cells and promote angiogenesis in glioblastomas.
Department of Neurosurgery/Neuro-oncology, Sun Yat-sen University Cancer Center, Guangzhou, China; State Key Laboratory of Oncology in South China, Guangzhou, China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
Xin
X
Mei
Department of Neurosurgery/Neuro-oncology, Sun Yat-sen University Cancer Center, Guangzhou, China; State Key Laboratory of Oncology in South China, Guangzhou, China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
Yin-Sheng
YS
Chen
Department of Neurosurgery/Neuro-oncology, Sun Yat-sen University Cancer Center, Guangzhou, China; State Key Laboratory of Oncology in South China, Guangzhou, China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
Fu-Rong
FR
Chen
Department of Neurosurgery/Neuro-oncology, Sun Yat-sen University Cancer Center, Guangzhou, China; State Key Laboratory of Oncology in South China, Guangzhou, China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
Shao-Yan
SY
Xi
Department of Neurosurgery/Neuro-oncology, Sun Yat-sen University Cancer Center, Guangzhou, China; State Key Laboratory of Oncology in South China, Guangzhou, China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
Zhong-Ping
ZP
Chen
D000818:Animals; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology; D002454:Cell Differentiation / Q000502:physiology*; D045744:Cell Line, Tumor; D042783:Endothelial Cells / Q000166:cytology*; D005909:Glioblastoma / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D051379:Mice; D014411:Neoplastic Stem Cells / Q000166:cytology*
differentiation; glioblastoma; live-cell imaging; primary brain tumor