New therapeutic target for pediatric anaplastic ependymoma control: study of anti-tumor activity by a Kunitz-type molecule, Amblyomin-X.

EPNs comprise a heterogeneous group of neuroepithelial tumors, accounting for about 10% of all intracranial tumors in children and up to 30% of brain tumors in those younger than 3 years. Actually, the pattern therapy for low-grade EPNs includes complete surgical resection followed by radiation therapy. Total surgical excision is often not possible due to tumor location. The aim of this study was to evaluate, for the first time, the anti-tumor activity of Amblyomin-X in 4 primary cultures derived from pediatric anaplastic posterior fossa EPN, Group A (anaplastic, WHO grade III) and one primary culture of a high grade neuroepithelial tumor with MN1 alteration, which was initially misdiagnosed as EPN: i) by in vitro assays: comparisons of temozolomide and cisplatin; ii) by intracranial xenograft model. Amblyomin-X was able to induce cell death in EPN cells in a more significant percentage compared to cisplatin. The cytotoxic effects of Amblyomin-X were not detected on hFSCs used as control, as opposed to cisplatin-treatment, which promoted a substantial effect in the hAFSCs viability. TEM analysis showed ultrastructural alterations related to the process of cell death: mitochondrial degeneration, autophagosomes and aggregate-like structures. MRI and histopathological analyzes demonstrated significant tumor mass regression. Our results suggest that Amblyomin-X has a selective effect on tumor cells by inducing apoptotic cell death and may be a therapeutic option for Group AEPNs.

Intravenous Grafts of Human Amniotic Fluid-Derived Stem Cells Reduce Behavioral Deficits in Experimental Ischemic Stroke.

Amniotic fluid has been investigated as new cell source for stem cells in the development of future cell-based transplantation. This study reports isolation of viable human amniotic fluid-derived stem cells, labeled with multimodal iron oxide nanoparticles, and its effect on focal cerebral ischemia-reperfusion injury in Wistar rats. Middle cerebral artery occlusion of 60 min followed by reperfusion for 1 h, 6 h, and 24 h was employed in the present study to produce ischemia and reperfusion-induced cerebral injury in rats. Tests were employed to assess the functional outcome of the sensorimotor center activity in the brain, through a set of modified neurological severity scores used to assess motor and exploratory capacity 24 h, 14, and 28 days after receiving cellular therapy via tail vein. In our animal model of stroke, transplanted cells migrated to the ischemic focus, infarct volume decreased, and motor deficits improved. Therefore, we concluded that these cells appear to have beneficial effects on the ischemic brain, possibly based on their ability to enhance endogenous repair mechanisms.

Tropism of mesenchymal stem cell toward CD133+ stem cell of glioblastoma in vitro and promote tumor proliferation in vivo.

BACKGROUND: Previous studies have demonstrated remarkable tropism of mesenchymal stem cells (MSCs) toward malignant gliomas, making these cells a potential vehicle for delivery of therapeutic agents to disseminated glioblastoma (GBM) cells. However, the potential contribution of MSCs to tumor progression is a matter of concern. It has been suggested that CD133+ GBM stem cells secrete a variety of chemokines, including monocytes chemoattractant protein-1 (MCP-1/CCL2) and stromal cell-derived factor-1(SDF-1/CXCL12), which could act in this tropism. However, the role in the modulation of this tropism of the subpopulation of CD133+ cells, which initiate GBM and the mechanisms underlying the tropism of MSCs to CD133+ GBM cells and their effects on tumor development, remains poorly defined. METHODS/RESULTS: We found that isolated and cultured MSCs (human umbilical cord blood MSCs) express CCR2 and CXCR4, the respective receptors for MCP-1/CCL2 and SDF-1/CXCL12, and demonstrated, in vitro, that MCP-1/CCL2 and SDF-1/CXC12, secreted by CD133+ GBM cells from primary cell cultures, induce the migration of MSCs. In addition, we confirmed that after in vivo GBM tumor establishment, by stereotaxic implantation of the CD133+ GBM cells labeled with Qdots (705 nm), MSCs labeled with multimodal iron oxide nanoparticles (MION) conjugated to rhodamine-B (Rh-B) (MION-Rh), infused by caudal vein, were able to cross the blood-brain barrier of the animal and migrate to the tumor region. Evaluation GBM tumors histology showed that groups that received MSC demonstrated tumor development, glial invasiveness, and detection of a high number of cycling cells. CONCLUSIONS: Therefore, in this study, we validated the chemotactic effect of MCP-1/CCL2 and SDF-1/CXCL12 in mediating the migration of MSCs toward CD133+ GBM cells. However, we observed that, after infiltrating the tumor, MSCs promote tumor growth in vivo probably by release of exosomes. Thus, the use of these cells as a therapeutic carrier strategy to target GBM cells must be approached with caution.

Lipid nanoemulsion passive tumor accumulation dependence on tumor stage and anatomical location: a new mathematical model for in vivo imaging biodistribution studies.

Nanoparticle delivery to tumor tissue is one of the most important applications of nanomedicine. However, the literature shows that this pharmacological event is highly-affected by several tumor biology characteristics, including tumor size and maturation. Thus, the objective of the present study is to report on the investigation of the biodistribution of a lipid nanoemulsion (NE) in a breast cancer tumor model using in vivo imaging techniques. As highlights of this study, we can indicate that the biodistribution was measured in different tumor sites (primary and metastatic tumors) and in the same experimental mice for four subsequent weeks. With this approach it is possible to observe that the NE tumor delivery is significantly altered during tumor growth and metastasis progression. Furthermore, in the present report we introduce a phenomenological mathematical model that successfully explains the delivery behavior of a hydrophobic infrared fluorescent NE marker to both primary tumor and metastatic lesions. We believe that these data, in addition to the phenomenological mathematical model, are relevant to understanding how the stage of tumor development can alter macromolecule and/or nanoparticle delivery to tumor tissues, thus improving the efficacy of the passive delivery features promoted by tumor biology.

Acid-sensitive lipidated doxorubicin prodrug entrapped in nanoemulsion impairs lung tumor metastasis in a breast cancer model.

AIM: To develop an acid-sensitive lipidated, doxorubicin (Dox) prodrug (C16-Dox) to be entrapped in lipid nanoemulsion (NE-C16-Dox) as a nanocarrier to treat breast cancer models (in vitro and in vivo). RESULTS: We report the efficacy of NE-C16-Dox in in vitro experiments, as well as the improved chemotherapeutic index and tumor-control efficacy compared with treatment with free Dox in an in vivo murine 4T1 breast cancer model. In addition, NE-C16-Dox allowed the use of a higher dose of Dox, acceptable biocompatibility and a significant reduction in lung metastasis. CONCLUSION: Taken together, these results indicate that NE-C16-Dox is promising for breast cancer treatment, thus creating possibilities to translate these nanotechnology concepts to clinical applications.

Mesenchymal stem cell-like properties of CD133+ glioblastoma initiating cells.

Glioblastoma is composed of dividing tumor cells, stromal cells and tumor initiating CD133+ cells. Recent reports have discussed the origin of the glioblastoma CD133+ cells and their function in the tumor microenvironment. The present work sought to investigate the multipotent and mesenchymal properties of primary highly purified human CD133+ glioblastoma-initiating cells. To accomplish this aim, we used the following approaches: i) generation of tumor subspheres of CD133+ selected cells from primary cell cultures of glioblastoma; ii) analysis of the expression of pluripotency stem cell markers and mesenchymal stem cell (MSC) markers in the CD133+ glioblastoma-initiating cells; iii) side-by-side ultrastructural characterization of the CD133+ glioblastoma cells, MSC and CD133+ hematopoietic stem cells isolated from human umbilical cord blood (UCB); iv) assessment of adipogenic differentiation of CD133+ glioblastoma cells to test their MSC-like in vitro differentiation ability; and v) use of an orthotopic glioblastoma xenograft model in the absence of immune suppression. We found that the CD133+ glioblastoma cells expressed both the pluripotency stem cell markers (Nanog, Mush-1 and SSEA-3) and MSC markers. In addition, the CD133+ cells were able to differentiate into adipocyte-like cells. Transmission electron microscopy (TEM) demonstrated that the CD133+ glioblastoma-initiating cells had ultrastructural features similar to those of undifferentiated MSCs. In addition, when administered in vivo to non-immunocompromised animals, the CD133+ cells were also able to mimic the phenotype of the original patient's tumor. In summary, we showed that the CD133+ glioblastoma cells express molecular signatures of MSCs, neural stem cells and pluripotent stem cells, thus possibly enabling differentiation into both neural and mesodermal cell types.

Differential neuroprotection by A(1) receptor activation and A(2A) receptor inhibition following pilocarpine-induced status epilepticus.

Aiming at a better understanding of the role of A(2A) in temporal lobe epilepsy (TLE), we characterized the effects of the A(2A) antagonist SCH58261 (7-(2-phenylethyl)-5-amino-2(2-furyl)-pyrazolo-[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine) on seizures and neuroprotection in the pilocarpine model. The effects of SCH58261 were further analyzed in combination with the A(1) agonist R-Pia (R(-)-N(6)-(2)-phenylisopropyl adenosine). Eight groups were studied: pilocarpine (Pilo), SCH+Pilo, R-Pia+Pilo, R-Pia+SCH+Pilo, Saline, SCH+Saline, R-Pia+Saline, and R-Pia+SCH+Saline. The administration of SCH58261, R-Pia, and R-Pia+SCH58261 prior to pilocarpine increased the latency to SE, and decreased either the incidence of or rate of mortality from SE compared with controls. Administration of R-Pia and R-Pia+SCH58261 prior to pilocarpine reduced the number of Fluoro-Jade B-stained cells in the hippocampus and piriform cortex when compared with control. This study showed that pretreatment with R-Pia and SCH58261 reduces seizure occurrence, although only R-Pia has neuroprotective properties. Further studies are needed to clarify the neuroprotective role of A(2A) in TLE.