Biomedical Engineering Reference
In-Depth Information
6.
Nanomedicine applications in brain tumors
In the last decade various studies have demonstrated the value of nano-
technology in brain tumor treatment. Nanomedicine can give many ideal
devices for delivery of specific compounds to brain tumors, loading them
into nanoparticle-based carriers via a variety of chemical methods including
encapsulation, adsorption and covalent linkage. In brain tumor treatment,
various molecules at different steps and pathways, such as cell immortaliza-
tion and apoptosis escape, tumor neoangiogenesis, and invasion of normal
tissues have been studied as possible targets of a novel therapeutic model.
Recent advances in molecular, biological and genetic diagnostic techniques
have evidenced new cerebral glioma-associated biomarkers and their impli-
cations for gliomas progression. The possibility to block the more contem-
porary pathway into glioma by molecular-based targeted approaches, using
a nanocarrier loaded with anti-cancer agent, represents an interesting thera-
peutic strategy. This new strategy could permit overcoming of the BBB and
to delivery drugs and/or genetic probes into brain tumor cells in a selec-
tive manner. The future challenges of this approach may be the possibility
to modify the cell genome, and induce it to a reversion into the wild-type
conditions, the enhancing of immune system anti-tumor capacity, and the
targeted drug-delivery into brain tumor cells. Bernardi et al. [185] evalu-
ated the efficacy of immunonanoshells in vitro against medulloblastoma and
malignant glioma cell lines. The authors, using an antibody against human
epidermal growth factor receptor (HER2) to target gold-silica nanoshells
to medulloblastoma cells, demonstrated cell death in the HER2-over-
expressing medulloblastoma cell lines, after exposure to laser light. In glioma
cell lines, they showed the capacity of these immunonanoshells in causing
leading cell death in U373 and U87 malignant glioma cell lines. This mecha-
nism may be very innovative also in the diagnosis of brain tumors. In fact,
nanoparticle targeting methods, iron-oxide nanoparticle-based MRI con-
trast agents, targeted nanoparticle-based MRI contrast agents and intraop-
erative nanoparticle-enabled brain tumor delineation, may produce contrast
enhancement at an earlier stage of gliomas [100]. Another emerging specific
contrast agent is represented by a nanoprobe that targets gliomas which
may express membrane-bound matrix metalloproteinase-2 (MMP-2). This
nanoprobe, named chlorotoxin-conjugated superparamagnetic nanoprobe
(PEG-coated nanoparticles), has the capacity to selectively detect neoplas-
tic cells in gliomas, medulloblastoma, prostate cancer, sarcoma, and intes-
tinal cancer [47]. Wang et al. [186] in a recent study have demonstrated,
using a molecular targeting of glioma cells through CD133 antigen over-
expressed on the surface of GBM cells, a prominent photothermal selective
damage of targeted glioma cells. Molecular targeting in this case has been
performed using carbon nanotubes, conjugated with anti-CD133 monoclo-
nal antibodies. The efficiency of liposomal and other nanoplatforms systems
