Transcriptional Characterization of Glioma Neural Stem Cells Diva ...

3.2 Brain Cancer Stem Cells Introduction
Figure 3.5: Glioblastoma treatment with BMPs. BMPs normally cause NS cells
to differentiate into astrocytes. When used to treat isolated glioblastoma CD133 +
cells, they weaken their tumourigenicity both in vitro and, when engrafted into mice,
in vivo. The knowledge that a tumour retains a developmental hierarchy suggests
that targeting different cell populations is a promising therapeutic strategy. Adapted
from Dirks et al 2006 [121].
because the true stem cells are probably a subpopulation of the CD133 + frac-
tion, as demonstrated in the study by Bao et al by the death rates of mice
after three months from treatment [123]. Another study attempting to eluci-
date the role of CD133 was conducted in vivo on mice that were injected with
100 to 1,000 uncultured malignant brain tumour cells purified by bead sorting
for CD133 [459]. These CD133 + cells reproduced a phenotypical copy of the
patient’s original tumour and were also heterogeneous, with only a minority
of cells expressing CD133. This suggested differentiation in vivo, making dif-
ferentiation therapy look like a real option for brain tumour treatment and
denoting that brain tumours of different types are also functionally heteroge-
neous for tumour-initiating ability [122].
Several other studies have since then focused on the isolation of functional can-
cer stem cell markers in different types and stages of brain tumours. In a study
by Balenci et al [39], the mammalian IQ motif containing GTPase activating
protein 1 (IQGAP1), considered to be a scaffolding protein at the intersection
of several signaling pathways such as control of cell adhesion, polarization, di-
rectional migration and neuronal motility, was found to be a reliable marker
of Nestin + amplifying neural progenitors in rat brain. This protein is highly
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