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Small interfering RNA (siRNA)-mediated transcriptional knockdown of urokinase plasminogen activator receptor (uPAR) and matrix metalloproteinase-9 (MMP-9), alone or in combination, inhibits uPAR and/or MMP-9 expression and induces apoptosis in the human glioblastoma xenograft cell lines 4910 and 5310. siRNA against uPAR (pU-Si), MMP-9 (pM-Si), or both (pUM-Si) induced apoptosis and was associated with the cleavage of caspase-8, caspase-3, and poly(ADP-ribose) polymerase. Furthermore, protein levels of the Fas receptor (APO-1/CD-95) were increased following transcriptional inactivation of uPAR and/or MMP-9. In addition, Fas siRNA against the Fas death receptor blocked apoptosis induced by pU-Si, pM-Si, or pUM-Si, thereby indicating the role for Fas signaling in pU-Si–, pM-Si–, or pUM-Si–mediated apoptotic cell death of human glioma xenograft cells. Thus, transcriptional inactivation of uPAR and/or MMP-9 enhanced localization of Fas death receptor, Fas-associated death domain-containing protein, and procaspase-8 into lipid rafts. Additionally, disruption of lipid rafts with methyl β cyclodextrin prevented Fas clustering and pU-Si–, pM-Si–, or pUM-Si–induced apoptosis, which is indicative of coclustering of Fas death receptor into lipid rafts in the glioblastoma xenograft cell lines 4910 and 5310. These data indicate the crucial role of the clusters of apoptotic signaling molecule-enriched rafts in programmed cell death, acting as concentrators of death receptors and downstream signaling molecules, and as the linchpin from which a potent death signal is launched in uPAR- and/or MMP-9–downregulated cells. Mol Cancer Ther; 9(9); 2605–17. ©2010 AACR.

Supplementary Figure 2 from Urokinase Plasminogen Activator Receptor and/or Matrix Metalloproteinase-9 Inhibition Induces Apoptosis Signaling through Lipid Rafts in Glioblastoma Xenograft Cells

Supplementary Figure 3 from Urokinase Plasminogen Activator Receptor and/or Matrix Metalloproteinase-9 Inhibition Induces Apoptosis Signaling through Lipid Rafts in Glioblastoma Xenograft Cells

Supplementary Figure Legends from Urokinase Plasminogen Activator Receptor and/or Matrix Metalloproteinase-9 Inhibition Induces Apoptosis Signaling through Lipid Rafts in Glioblastoma Xenograft Cells

Supplementary Figure 1 from Urokinase Plasminogen Activator Receptor and/or Matrix Metalloproteinase-9 Inhibition Induces Apoptosis Signaling through Lipid Rafts in Glioblastoma Xenograft Cells

Supplementary Figure Legends 1-4 from SPARC Stimulates Neuronal Differentiation of Medulloblastoma Cells via the Notch1/STAT3 Pathway

Supplementary Figure 3 from SPARC Stimulates Neuronal Differentiation of Medulloblastoma Cells via the Notch1/STAT3 Pathway

Supplementary Figure 1 from SPARC Stimulates Neuronal Differentiation of Medulloblastoma Cells via the Notch1/STAT3 Pathway

Supplementary Figure 4 from SPARC Stimulates Neuronal Differentiation of Medulloblastoma Cells via the Notch1/STAT3 Pathway

Supplementary Figure 2 from SPARC Stimulates Neuronal Differentiation of Medulloblastoma Cells via the Notch1/STAT3 Pathway

Background Magnetic nanoparticles (MNPs) hold promise for enhancing delivery of therapeutic agents, either through direct binding or by functioning as miniature propellers. Fluid-filled conduits and reservoirs within the body offer avenues for MNP-enhanced drug delivery. MNP clusters can be rotated and moved across surfaces at clinically relevant distances in response to a rotating magnet. Limited data are available regarding issues affecting MNP delivery by this mechanism, such as adhesion to a cellular wall. Research reported here was initiated to better understand the fundamental principles important for successful implementation of rotational magnetic drug targeting (rMDT). Methods Translational movements of four different iron oxide MNPs were tested, in response to rotation (3 Hz) of a neodymium-boron-iron permanent magnet. MNP clusters moved along biomimetic channels of a custom-made acrylic tray, by surface walking. The effects of different distances and cellular coatings on MNP velocity were analyzed using videography. Dyes (as drug surrogates) and the drug etoposide were transported by rotating MNPs along channels over a 10 cm distance. Results MNP translational velocities could be predicted from magnetic separation times. Changes in distance or orientation from the magnet produced alterations in MNP velocities. Mean velocities of the fastest MNPs over HeLa, U251, U87, and E297 cells were 0.24 ± 0.02, 0.26 ± 0.02, 0.28 ± 0.01, and 0.18 ± 0.03 cm/sec, respectively. U138 cells showed marked MNP adherence and an 87.1% velocity reduction at 5.5 cm along the channel. Dye delivery helped visualize the effects of MNPs as microdevices for drug delivery. Dye delivery by MNP clusters was 21.7 times faster than by diffusion. MNPs successfully accelerated etoposide delivery, with retention of chemotherapeutic effect. Conclusion The in vitro system described here facilitates side-by-side comparisons of drug delivery by rotating MNP clusters, on a human scale. Such microdevices have the potential for augmenting drug delivery in a variety of clinical settings, as proposed.

Alexander J Willis,1 Sebastian P Pernal,2 Zachary A Gaertner,3 Sajani S Lakka,1 Michael E Sabo,4 Francis M Creighton,4 Herbert H Engelhard5 1Division of Hematology-Oncology, Department of Medicine, The University of Illinois at Chicago, Chicago, IL, USA; 2Wayne State University, Detroit, MI, USA; 3Northwestern University, Chicago, IL, USA; 4Pulse Therapeutics, Inc, St. Louis, MO, USA; 5Departments of Neurosurgery and Bioengineering, The University of Illinois at Chicago, Chicago, IL, USACorrespondence: Herbert H EngelhardThe University of Illinois at Chicago, 912 South Wood St., Chicago, IL 60612, USATel +1 312 996-4842Email hengelhard@sbcglobal.netBackground: Magnetic nanoparticles (MNPs) hold promise for enhancing delivery of therapeutic agents, either through direct binding or by functioning as miniature propellers. Fluid-filled conduits and reservoirs within the body offer avenues for MNP-enhanced drug delivery. MNP clusters can be rotated and moved across surfaces at clinically relevant distances in response to a rotating magnet. Limited data are available regarding issues affecting MNP delivery by this mechanism, such as adhesion to a cellular wall. Research reported here was initiated to better understand the fundamental principles important for successful implementation of rotational magnetic drug targeting (rMDT).Methods: Translational movements of four different iron oxide MNPs were tested, in response to rotation (3 Hz) of a neodymium–boron–iron permanent magnet. MNP clusters moved along biomimetic channels of a custom-made acrylic tray, by surface walking. The effects of different distances and cellular coatings on MNP velocity were analyzed using videography. Dyes (as drug surrogates) and the drug etoposide were transported by rotating MNPs along channels over a 10 cm distance.Results: MNP translational velocities could be predicted from magnetic separation times. Changes in distance or orientation from the magnet produced alterations in MNP velocities. Mean velocities of the fastest MNPs over HeLa, U251, U87, and E297 cells were 0.24 ± 0.02, 0.26 ± 0.02, 0.28 ± 0.01, and 0.18 ± 0.03 cm/sec, respectively. U138 cells showed marked MNP adherence and an 87.1% velocity reduction at 5.5 cm along the channel. Dye delivery helped visualize the effects of MNPs as microdevices for drug delivery. Dye delivery by MNP clusters was 21.7 times faster than by diffusion. MNPs successfully accelerated etoposide delivery, with retention of chemotherapeutic effect.Conclusion: The in vitro system described here facilitates side-by-side comparisons of drug delivery by rotating MNP clusters, on a human scale. Such microdevices have the potential for augmenting drug delivery in a variety of clinical settings, as proposed.Keywords: etoposide, glioblastoma, iron oxide nanoparticles, in vitro model, lung cancer, magnetic drug targeting, nanodevice

Angiogenesis is the growth of new capillaries from the preexisting blood vessels. Glioblastoma (GBM) tumors are highly vascularized tumors, and glioma growth depends on the formation of new blood vessels. Angiogenesis is a complex process involving proliferation, migration, and differentiation of vascular endothelial cells (ECs) under the stimulation of specific signals. It is controlled by the balance between its promoting and inhibiting factors. Various angiogenic factors and genes have been identified that stimulate glioma angiogenesis. Therefore, attention has been directed to anti-angiogenesis therapy in which glioma proliferation is inhibited by inhibiting the formation of new tumor vessels using angiogenesis inhibitory factors and drugs. Here, in this review, we highlight and summarize the various molecular mediators that regulate GBM angiogenesis with focus on recent clinical research on the potential of exploiting angiogenic pathways as a strategy in the treatment of GBM patients.

We previously showed that MMP-9 inhibition using an adenoviral-mediated delivery of MMP-9 siRNA (Ad-MMP-9), caused senescence in medulloblastoma cells. Regardless of whether or not, Ad-MMP-9 would induce apoptosis, the possible signaling mechanism is still obscure. In this report, we demonstrate that Ad-MMP-9 induced apoptosis in DAOY cells as determined by propidium iodide and TUNEL staining. Ad-MMP-9 infection induced the release of cytochrome-c, activation of caspases-9-3, and cleavage of PARP. Ad-MMP-9 infection stimulated ERK, and EMSA indicated an increase in NF-κB activation. ERK inhibition, using kinase dead mutant for ERK, ameliorated NF-κB activation and caspase-mediated apoptosis in Ad-MMP-9 infected cells. β1-integrin expression in Ad-MMP-9 infected cells also increased, and this increase was reversed by the reintroduction of MMP-9. We found that, addition of β1 blocking antibodies inhibited Ad-MMP-9-induced ERK activation. Taken together, our results indicate that MMP-9 inhibition induces apoptosis due to altered β1 integrin expression in medulloblastoma. In addition, ERK activation plays an active role in this process and functions upstream of NF-κB activation to initiate the apoptotic signal.

The invasive ability of tumor cells plays a key role in prostate cancer metastasis and is a major cause of treatment failure. Urokinase plasminogen activator (uPA) and its receptor (uPAR)-mediated signaling have been implicated in tumor cell invasion, survival and metastasis in a variety of cancers. This study was undertaken to investigate the biological roles of uPA and uPAR in prostate cancer cell invasion, survival and the potential of uPA and uPAR as targets for prostate cancer therapy. uPA and uPAR expression correlates with the metastatic potential of prostate cancer cells. Thus, therapies designed to inhibit uPA and uPAR expression would be beneficial. LNCaP, DU145 and PC3 are prostate cancer cell lines with low, moderate and high metastatic potential, respectively, as demonstrated by their capacity to invade extracellular matrix (ECM). In this study we utilized small hairpin RNAs (shRNAs), also referred to as small interfering RNAs (siRNAs), to target human uPA and uPAR. These siRNA constructs significantly inhibited uPA and uPAR expression at both the mRNA and protein levels in the highly metastatic prostate cancer cell line PC3. Our data demonstrate that uPA-uPAR knockdown in PC3 cells resulted in a dramatic reduction of tumor cell invasion as indicated by a matrigel invasion assay. Furthermore, simultaneous silencing of the genes for uPA and uPAR using a single plasmid construct expressing shRNAs for both uPA and uPAR significantly reduced cell viability and ultimately resulted in the induction of apoptotic cell death. RNAi for uPA and uPAR also abrogated uPA-uPAR signaling to downstream target molecules such as extracellular-signal regulated kinases 1/2 (ERK1/2) and the signal transducer and activator of transcription 3 (Stat 3). In addition, our results demonstrate that intratumoral injection with the plasmid construct expressing shRNAs for uPA and uPAR almost completely inhibited established tumor growth and survival in an orthotopic mouse prostate cancer model. These findings uncovered evidence of a complex signaling network operating downstream of uPA-uPAR that actively advances tumor cell invasion, proliferation and survival of prostate cancer cells. Thus, RNAi-directed targeting of uPA and uPAR is a convenient and novel tool for studying the biological role of the uPA-uPAR system and raises the potential of its application for prostate cancer therapy.

We have previously demonstrated the effectiveness of adenovirus-mediated expression of antisense urokinase-type plasminogen activator receptor (uPAR) and matrix metalloproteinase-9 (MMP-9) in inhibiting tumor invasion in vitro and ex vivo. However, the therapeutic effect of the adenovirus-mediated antisense approach was shown to be transient and required potentially toxic, high viral doses. In contrast, RNA interference (RNAi)-mediated gene targeting may be superior to the traditional antisense approach, because the target mRNA is completely degraded and the molar ratio of siRNA required to degrade the target mRNA is very low. Here, we have examined the siRNA-mediated target RNA degradation of uPAR and MMP-9 in human glioma cell lines. Using RNAi directed toward uPAR and MMP-9, we achieved specific inhibition of uPAR and MMP-9. This bicistronic construct (pUM) inhibited the formation of capillary-like structures in both in vitro and in vivo models of angiogenesis. We demonstrated that blocking the expression of these genes results in significant inhibition of glioma tumor invasion in Matrigel and spheroid invasion assay models. RNAi for uPAR and MMP-9 inhibited cell proliferation, and significantly reduced the levels of phosphorylated forms of MAPK, ERK, and AKT signaling pathway molecules when compared with parental and empty vector/scrambled vector-transfected SNB19 cells. Furthermore, using RNAi to simultaneously target two proteases resulted in total regression of pre-established intracerebral tumor growth. Our results provide evidence that the use of hairpin siRNA expression vectors for uPAR and MMP-9 may provide an effective tool for cancer therapy.

The development of curative treatment for glioblastoma has been extremely challenging. Chemotherapeutic agents that have seemed promising have failed in clinical trials. Drugs that can successfully target cancer cells within the brain must first traverse the brain interstitial fluid. Cerebral microdialysis (CMD) is an invasive technique in which interstitial fluid can be directly sampled. CMD has primarily been used clinically in the setting of head trauma and subarachnoid hemorrhage. Our goal was to review the techniques, principles, and new data pertaining to CMD to highlight its use in neuro-oncology. We conducted a literature search using the PubMed database and selected studies in which the investigators had used CMD in either animal brain tumor models or clinical trials. The references were reviewed for additional information. Studies of CMD have shown its importance as a neurosurgical technique. CMD allows for the collection of pharmacokinetic data on drug penetrance across the blood–brain barrier and metabolic data to characterize the response to chemotherapy. Although no complications have been reported, the current CMD technique (as with any procedure) has risks and limitations, which we have described in the present report. Animal CMD experiments have been used to exclude central nervous system drug candidates from progressing to clinical trials. At present, patients undergoing CMD have been monitored in the intensive care unit, owing to the requisite tethering to the apparatus. This can be expected to change soon because of advances in microminiaturization. CMD is an extremely valuable, yet underused, technique. Future CMD applications will have central importance in assessing drug delivery to tumor cells in vivo, allowing a pathway to successful therapy for malignant brain tumors.