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1.  The Somatic Genomic Landscape of Glioblastoma 
Cell  2013;155(2):462-477.
We describe the landscape of somatic genomic alterations based on multi-dimensional and comprehensive characterization of more than 500 glioblastoma tumors (GBMs). We identify several novel mutated genes as well as complex rearrangements of signature receptors including EGFR and PDGFRA. TERT promoter mutations are shown to correlate with elevated mRNA expression, supporting a role in telomerase reactivation. Correlative analyses confirm that the survival advantage of the proneural subtype is conferred by the G-CIMP phenotype, and MGMT DNA methylation may be a predictive biomarker for treatment response only in classical subtype GBM. Integrative analysis of genomic and proteomic profiles challenges the notion of therapeutic inhibition of a pathway as an alternative to inhibition of the target itself. These data will facilitate the discovery of therapeutic and diagnostic target candidates, the validation of research and clinical observations and the generation of unanticipated hypotheses that can advance our molecular understanding of this lethal cancer.
PMCID: PMC3910500  PMID: 24120142
2.  Polymalic Acid-based Nano Biopolymers for Targeting of Multiple Tumor Markers: An Opportunity for Personalized Medicine? 
Tumors with similar grade and morphology often respond differently to the same treatment because of variations in molecular profiling. To account for this diversity, personalized medicine is developed for silencing malignancy associated genes. Nano drugs fit these needs by targeting tumor and delivering antisense oligonucleotides for silencing of genes. As drugs for the treatment are often administered repeatedly, absence of toxicity and negligible immune response are desirable. In the example presented here, a nano medicine is synthesized from the biodegradable, non-toxic and non-immunogenic platform polymalic acid by controlled chemical ligation of antisense oligonucleotides and tumor targeting molecules. The synthesis and treatment is exemplified for human Her2-positive breast cancer using an experimental mouse model. The case can be translated towards synthesis and treatment of other tumors.
PMCID: PMC4118553  PMID: 24962356
Chemistry; Issue 88; Cancer treatment; personalized medicine; polymalic acid; nanodrug; biopolymer; targeting; host compatibility; biodegradability
3.  The optimization of polymalic acid peptide copolymers for endosomolytic drug delivery 
Biomaterials  2011;32(22):5269-5278.
Membranolytic macromolecules are promising vehicles forcytoplasmic drug delivery, but their efficiency and safety remains primary concerns. To address those concerns, membranolytic properties of various poly(β-l-malic acid) (PMLA) copolymers were extensively investigated as a function of concentration and pH. PMLA, a naturally occurring biodegradable polymer, acquires membranolytic activities after substitution of pendant carboxylates with hydrophobic amino acid derivatives. Ruled by hydrophobization and charge neutralization, membranolysis of PMLA copolymers increased as a function of polymer molecular weight and demonstrated a maximum with 50% substitution of carboxylates. Charge neutralization was achieved either conditionally by pH-dependent protonation or permanently by masking carboxylates. Membranolysis of PMLA copolymers containing tripeptide ofleucine, tryptophan and phenylalanine were pH-dependent in contrast to pH-independent copolymers of Leucineethylester and Leu-Leu-Leu-NH2 with permanent charge neutralization. PMLA and tripeptides seemed a unique combination for pH-dependent membranolysis. In contrast to nontoxic pH-dependent PMLA copolymers, pH-independent copolymers were found toxic at high concentration, which is ascribed to their nonspecific disruption of plasma membrane at physiological pH.pH-dependent copolymers were membranolytically active only at acidic pH typical of maturating endosomes, and are thus devoid of cytotoxicity. The PMLA tripeptide copolymers are useful for safe and efficient cytoplasmic delivery routed through endosome.
PMCID: PMC4110056  PMID: 21514661
4.  Polymalic Acid-based Nano Biopolymers for Targeting of Multiple Tumor Markers: An Opportunity for Personalized Medicine? 
Tumors with similar grade and morphology often respond differently to the same treatment because of variations in molecular profiling. To account for this diversity, personalized medicine is developed for silencing malignancy associated genes. Nano drugs fit these needs by targeting tumor and delivering antisense oligonucleotides for silencing of genes. As drugs for the treatment are often administered repeatedly, absence of toxicity and negligible immune response are desirable. In the example presented here, a nano medicine is synthesized from the biodegradable, non-toxic and non-immunogenic platform polymalic acid by controlled chemical ligation of antisense oligonucleotides and tumor targeting molecules. The synthesis and treatment is exemplified for human Her2-positive breast cancer using an experimental mouse model. The case can be translated towards synthesis and treatment of other tumors.
PMCID: PMC4118553  PMID: 24962356
Chemistry; Issue 88; Cancer treatment; personalized medicine; polymalic acid; nanodrug; biopolymer; targeting; host compatibility; biodegradability
5.  Toxicity and efficacy evaluation of multiple targeted polymalic acid conjugates for triple-negative breast cancer treatment 
Journal of drug targeting  2013;21(10):956-967.
Engineered nanoparticles are widely used for delivery of drugs but frequently lack proof of safety for cancer patient's treatment. All-in-one covalent nanodrugs of the third generation have been synthesized based on a poly(β-L-malic acid) (PMLA) platform, targeting human triple-negative breast cancer (TNBC). They significantly inhibited tumor growth in nude mice by blocking synthesis of epidermal growth factor receptor, and α4 and β1 chains of laminin-411, the tumor vascular wall protein and angiogenesis marker. PMLA and nanodrug biocompatibility and toxicity at low and high dosages were evaluated in vitro and in vivo. The dual-action nanodrug and single-action precursor nanoconjugates were assessed under in vitro conditions and in vivo with multiple treatment regimens (6 and 12 treatments). The monitoring of TNBC treatment in vivo with different drugs included blood hematologic and immunologic analysis after multiple intravenous administrations. The present study demonstrates that the dual-action nanoconju-gate is highly effective in preclinical TNBC treatment without side effects, supported by hematologic and immunologic assays data. PMLA-based nanodrugs of the Polycefin™ family passed multiple toxicity and efficacy tests in vitro and in vivo on preclinical level and may prove to be optimized and efficacious for the treatment of cancer patients in the future.
PMCID: PMC4043297  PMID: 24032759
Hematologic; immunogenicity; in vivo treatment; nanoconjugate drugs; polymalic acid; toxicity; triple-negative breast cancer
6.  Glioma Stem Cell Research for the development of Immunotherapy 
Glioma, especially high-grade glioblastoma multiforme (GBM), is the most common and aggressive type of brain tumor, accounting for about half of all the primary brain tumors. Despite continued advances in surgery, chemotherapy and radiotherapy, the clinical outcomes remain dismal. The two-year survival rate of GBM is <30%. Better understanding of GBM biology is desirable to develop novel therapies. Recent studies have demonstrated the existence of a small subpopulation of cells with stem like features cancer stem cells otherwise known as (CSC). These GBM CSCs are self-renewable and highly tumorigenic. They are not only chemo-radio- resistant, but also often multi-drug resistance genes and drug transporter genes. These characteristic enable GBM CSCs to survive standard cytotoxic therapies. Among GBM CSCs, CD133+ cells are a well-defined population and are prospectively isolated by their cell-surface marker. There are increasing data that CD133+ CSC presence highly correlates with patient survival. This makes it an ideal immunotherapy target population. In this article, we will review recent studies related with GBM CSCs, particularly CD133+ CSCs as well as the novel therapeutic strategies targeting these cells.
PMCID: PMC2786895  PMID: 19944974
cancer stem cell; glioma; CD133+; immunotherapy
7.  Angiotensin-converting enzyme overexpression in myelomonocytes prevents Alzheimer’s-like cognitive decline 
The Journal of Clinical Investigation  2014;124(3):1000-1012.
Cognitive decline in patients with Alzheimer’s disease (AD) is associated with elevated brain levels of amyloid β protein (Aβ), particularly neurotoxic Aβ1–42. Angiotensin-converting enzyme (ACE) can degrade Aβ1–42, and ACE overexpression in myelomonocytic cells enhances their immune function. To examine the effect of targeted ACE overexpression on AD, we crossed ACE10/10 mice, which overexpress ACE in myelomonocytes using the c-fms promoter, with the transgenic APPSWE/PS1ΔE9 mouse model of AD (AD+). Evaluation of brain tissue from these AD+ACE10/10 mice at 7 and 13 months revealed that levels of both soluble and insoluble brain Aβ1–42 were reduced compared with those in AD+ mice. Furthermore, both plaque burden and astrogliosis were drastically reduced. Administration of the ACE inhibitor ramipril increased Aβ levels in AD+ACE10/10 mice compared with the levels induced by the ACE-independent vasodilator hydralazine. Overall, AD+ACE10/10 mice had less brain-infiltrating cells, consistent with reduced AD-associated pathology, though ACE-overexpressing macrophages were abundant around and engulfing Aβ plaques. At 11 and 12 months of age, the AD+ACE10/WT and AD+ACE10/10 mice were virtually equivalent to non-AD mice in cognitive ability, as assessed by maze-based behavioral tests. Our data demonstrate that an enhanced immune response, coupled with increased myelomonocytic expression of catalytically active ACE, prevents cognitive decline in a murine model of AD.
PMCID: PMC3934162  PMID: 24487585
8.  Distinct mechanisms of membrane permeation induced by two polymalic acid copolymers 
Biomaterials  2012;34(1):217-225.
Anionic polymers are valuable components used in cosmetics and health sciences, especially in drug delivery, because of their chemical versatility and low toxicity. However, because of their highly negative charge they pose problems for penetration through hydrophobic barriers such as membranes. We have engineered anionic polymalic acid (PMLA) to penetrate biological membranes. PMLA copolymers of leucine ethyl ester (P/LOEt) or trileucine (P/LLL) show either pH-independent or pH-dependent activity for membrane penetration. We report here for the first time on the mechanisms which are different for those two copolymers. Formation of hydrophobic patches in either copolymer is detected by fluorescence techniques. The copolymers display distinctly different properties in solution and during membranolysis. P/LOEt copolymer binds to membrane as single molecules with high affinity, and induces leakage cooperatively through a mechanism known as “carpet” model, in which the polymer aligns at the surface throughout the entire process of membrane permeation. In contrast, P/LLL self-assembles to form an oligomer of 105 nm in a pH-dependent manner (pKa 5.5) and induces membrane leakage through a two-phase process: the concentration dependent first-phase of insertion of the oligomer into membrane followed by a concentration independent second-phase of rearrangement of the membrane-oligomer complex. The insertion of P/LLL is facilitated by hydrophobic interactions between trileucine side chains and lipids in the membrane core, resulting in transmembrane pores, through mechanism known as “barrel-stave” model. The understanding of the mechanism paves the way for future engineering of polymeric delivery systems with optimal cytoplasmic delivery efficiency and reduced systemic toxicity.
PMCID: PMC3487713  PMID: 23063368
9.  High levels of phosphorylated MAP kinase are associated with poor survival among patients with glioblastoma during the temozolomide era 
Neuro-Oncology  2012;15(1):104-111.
We investigated whether high levels of activated mitogen-activated protein kinase (p-MAPK) were associated with poor survival among patients with newly diagnosed glioblastoma during the temozolomide era. Nuclear p-MAPK expression of 108 patients with GBM was quantified and categorized in the following levels: low (0%–10%), medium (11%–40%), and high (41%–100%). Independent predictors of overall survival were determined using a multivariate Cox proportional hazards model. Our study included 108 patients with newly diagnosed GBM. Median age was 65 years, and 74% had high Karnofsky performance status (KPS ≥ 80). Median overall survival among all patients was 19.5 months. Activated MAPK expression levels of <10%, 11%–40%, and ≥41% were observed in 33 (30.6%), 37 (34.3%), and 38 (35.2%) patients, respectively. Median survival for low, medium, and high p-MAPK expression was 32.4, 18.2, and 12.5 months, respectively. Multivariate analysis showed 2.4-times hazard of death among patients with intermediate p-MAPK than low p-MAPK expression (hazard ratio [HR], 2.4; P = .02); high-expression patients were 3.9 times more likely to die, compared with patients with low p-MAPK (HR, 3.9; P = .007). Patients aged ≥65 years (HR, 2.8; P = .002) with KPS < 80 (HR, 3.1; P = .0003) and biopsy or partial resection (HR, 1.9; P = .02) had higher hazard of death. MGMT and PTEN expression were not associated with survival differences. This study provides quantitative means of evaluating p-MAPK in patients with GBM. It confirms the significant and independent prognostic relevance of p-MAPK in predicting survival of patients with GBM treated in the temozolomide era and highlights the need for therapies targeting the p-MAPK oncogenic pathway.
PMCID: PMC3534422  PMID: 23115159
EGFR; glioblastoma multiforme (GBM); IDH1; MGMT; overall survival; PTEN; p-MAPK
10.  Exploitation of adaptive evolution in glioma treatment 
CNS oncology  2013;2(2):171-179.
Glioblastoma multiforme (GBM) is a malignant neoplasm of the CNS with almost uniform lethality. Even with standard-of-care treatments, the prognosis for patients remains dismal. GBM, as with other malignancies, often acquires treatment resistance after an initial response to therapy. Treatment resistance may come about through the adaptive evolution of tumors in response to selection pressures from treatment interventions and the microenvironment. This review discusses how adaptive evolution might potentially be exploited as a new paradigm in GBM treatment.
PMCID: PMC3746825  PMID: 23977426
11.  PDE5 Inhibitors Enhance Tumor Permeability and Efficacy of Chemotherapy in a Rat Brain Tumor Model 
Brain research  2008;1230:290-302.
The blood-brain tumor barrier (BTB) significantly limits delivery of therapeutic concentrations of chemotherapy to brain tumors. A novel approach to selectively increase drug delivery is pharmacologic modulation of signaling molecules that regulate BTB permeability, such as those in cGMP signaling. Here we show that oral administration of sildenafil (Viagra) and vardenafil (Levitra), inhibitors of cGMP-specific PDE5, selectively increased tumor capillary permeability in 9L gliosarcoma-bearing rats with no significant increase in normal brain capillaries. Tumor-bearing rats treated with the chemotherapy agent, adriamycin, in combination with vardenafil survived significantly longer than rats treated with adriamycin alone. The selective increase in tumor capillary permeability appears to be mediated by a selective increase in tumor cGMP levels and increased vesicular transport through tumor capillaries, and could be attenuated by iberiotoxin, a selective inhibitor for calcium-dependent potassium (KCa) channels, that are effectors in cGMP signaling. The effect by sildenafil could be further increased by simultaneously using another BTB “opener”, bradykinin. Collectively, this data demonstrates that oral administration of PDE5 inhibitors selectively increases BTB permeability and enhance anti-tumor efficacy for a chemotherapeutic agent. These findings have significant implications for improving delivery of anti-tumor agents to brain tumors.
PMCID: PMC2632551  PMID: 18674521
brain tumor; PDE5 inhibitor; drug transport; drug delivery; blood-brain barrier; blood-brain tumor barrier
12.  Different Effects of KCa and KATP Agonists on Brain Tumor Permeability between Syngeneic and Allogeneic Rat Models 
Brain research  2008;1227:198-206.
The blood-brain tumor barrier (BTB) significantly limits delivery of effective concentrations of chemotherapeutic drugs to brain tumors. Previous studies suggest that BTB permeability may be modulated via alteration in the activity of potassium channels. In this study, we studied the relationship of BTB permeability increase mediated by potassium channel agonists to channel expression in two rat brain tumor models. Intravenous infusion of KCO912 (KATP agonist), minoxidil sulfate (KATP agonist) or NS1619 (KCa agonist) increased tumor permeability more in the 9L allogeneic brain tumor model than in the syngeneic brain tumor model. Consistently, expression of both KATP and KCa channels in 9L tumors was increased to a significantly greater extent in Wistar rats (allogeneic) as compared to Fischer rats (syngeneic). Furthermore, as a preliminary effort to understand clinical implication of potassium channels in brain tumor treatment, we determined the expression of KATP in surgical specimens. KATP mRNA was detected in glioblastoma multiforme (GBM) from nineteen patients examined, with a wide range of expression levels. Interestingly, in paired GBM tissues from seven patients before and after vaccination therapy, increased levels of KATP were detected in five patients after vaccination that had positive response to chemotherapy after vaccination. The present study indicates that the effects of potassium channel agonists on BTB permeability are different between syngeneic and allogeneic models which have different expression levels of potassium channels. The expression of potassium channels in brain tumors is variable, which may be associated with different tumor permeability to therapeutic agents among patients.
PMCID: PMC2605468  PMID: 18602898
Blood-brain barrier; Potassium channel; chemotherapy; Brain tumor model
13.  Nanoplatforms for constructing new approaches to cancer treatment, imaging, and drug delivery: What should be the policy? 
NeuroImage  2010;54(Suppl 1):S106-S124.
Nanotechnology is the design and assembly of submicroscopic devices called nanoparticles, which are 1–100 nm in diameter. Nanomedicine is the application of nanotechnology for the diagnosis and treatment of human disease. Disease-specific receptors on the surface of cells provide useful targets for nanoparticles. Because nanoparticles can be engineered from components that (1) recognize disease at the cellular level, (2) are visible on imaging studies, and (3) deliver therapeutic compounds, nanotechnology is well suited for the diagnosis and treatment of a variety of diseases. Nanotechnology will enable earlier detection and treatment of diseases that are best treated in their initial stages, such as cancer. Advances in nanotechnology will also spur the discovery of new methods for delivery of therapeutic compounds, including genes and proteins, to diseased tissue. A myriad of nanostructured drugs with effective site-targeting can be developed by combining a diverse selection of targeting, diagnostic, and therapeutic components. Incorporating immune target specificity with nanostructures introduces a new type of treatment modality, nano-immunochemotherapy, for patients with cancer. In this review, we will discuss the development and potential applications of nanoscale platforms in medical diagnosis and treatment. To impact the care of patients with neurological diseases, advances in nanotechnology will require accelerated translation to the fields of brain mapping, CNS imaging, and nanoneurosurgery. Advances in nanoplatform, nano-imaging, and nano-drug delivery will drive the future development of nanomedicine, personalized medicine, and targeted therapy. We believe that the formation of a science, technology, medicine law–healthcare policy (STML) hub/center, which encourages collaboration among universities, medical centers, US government, industry, patient advocacy groups, charitable foundations, and philanthropists, could significantly facilitate such advancements and contribute to the translation of nanotechnology across medical disciplines.
PMCID: PMC3524337  PMID: 20149882
Nanoplatforms; Nanotechnology; Image-guided therapy; Nanomedicine; Nanoneurosurgery; Nanostructures; Contrast agents; Nanoparticles; Nanotechnology policy; Nano-radiology; Nano-neuroscience; Nano-neurology
Laminins are the major constituents of blood vessel basement membranes (BMs). Each laminin is a trimer consisting of three assembled polypeptide chains, α, β and γ. More than 15 laminin isoforms are known to date and the expression of specific isoforms may change in certain pathological conditions. Here we show that during progression of glial tumors laminin-9 (α4β2γ1) is switched to laminin-8 (α4β1γ1), which is dramatically increased in glial brain tumors. Laminin-8 overproduction by glial tumor cells facilitates spread of glioma. Brain tumors with laminin-8 overexpression recur faster after standard treatment and patients have shorter survival time. Laminin-8 may be thus used as a predictor of tumor recurrence, patient survival and as a potential molecular target for glioma therapy.
PMCID: PMC3506377  PMID: 16146715
Laminin-8; Laminin-9; Basement Membrane; Extracellular Matrix; Angiogenesis; Human; Cancer; Tumor; Neoplasm; Glioma; Glioblastoma Multiforme; Recurrence; Survival; Invasion; Morpholino antisense; Review
15.  Inhibition of laminin-8 in vivo using a novel poly(malic acid)-based carrier reduces glioma angiogenesis 
Angiogenesis  2006;9(4):183-191.
We have previously shown that laminin-8, a vascular basement membrane component, was over-expressed in human glioblastomas multiforme and their adjacent tissues compared to normal brain. Increased laminin-8 correlated with shorter glioblastoma recurrence time and poor patient survival making it a potential marker for glioblastoma diagnostics and prediction of disease outcome. However, laminin-8 therapeutic potential was unknown because the technology of blocking the expression of multi-chain complex proteins was not yet developed. To inhibit the expression of laminin-8 constituents in glioblastoma in vitro and in vivo, we used Polycefin, a bioconjugate drug delivery system based on slime-mold Physarum polycephalum-derived poly(malic acid). It carries an attached transferrin receptor antibody to target tumor cells and to deliver two conjugated morpholino antisense oligonucleotides against laminin-8 α4 and β1 chains. Polycefin efficiently inhibited the expression of both laminin-8 chains by cultured glioblastoma cells. Intracranial Polycefin treatment of human U87MG glioblastoma-bearing nude rats reduced incorporation of both tumor-derived laminin-8 chains into vascular basement membranes. Polycefin was thus able to simultaneously inhibit the expression of two different chains of a complex protein. The treatment also significantly reduced tumor microvessel density (p < 0.001) and area (p < 0.001) and increased animal survival (p < 0.0004). These data suggest that laminin-8 may be important for glioblastoma angiogenesis. Polycefin, a versatile nanoscale drug delivery system, was suitable for in vivo delivery of two antisense oligonucleotides to brain tumor cells causing a reduction of glioblastoma angiogenesis and an increase of animal survival. This system may hold promise for future clinical applications.
PMCID: PMC3487708  PMID: 17109197
Tumor angiogenesis; Glioma; Laminin-8; Multiple drug targeting; Poly(malic acid)
16.  Polycefin, a New Prototype of a Multifunctional Nanoconjugate Based on Poly(β-l-malic acid) for Drug Delivery 
Bioconjugate chemistry  2006;17(2):317-326.
A new prototype of nanoconjugate, Polycefin, was synthesized for targeted delivery of antisense oligonucleotides and monoclonal antibodies to brain tumors. The macromolecular carrier contains: 1. biodegradable, nonimmunogenic, nontoxic β-poly(l-malic acid) of microbial origin; 2. Morpholino antisense oligonucleotides targeting laminin α4 and β1 chains of laminin-8, which is specifically overexpressed in glial brain tumors; 3. monoclonal anti-transferrin receptor antibody for specific tissue targeting; 4. oligonucleotide releasing disulfide units; 5. l-valine containing, pH-sensitive membrane disrupting unit(s), 6. protective poly(ethylene glycol); 7. a fluorescent dye (optional). Highly purified modules were conjugated directly with N-hydroxysuccinimidyl ester-activated β-poly-(l-malic acid) at pendant carboxyl groups or at thiol containing spacers via thioether and disulfide bonds. Products were chemically validated by physical, chemical, and functional tests. In vitro experiments using two human glioma cell lines U87MG and T98G demonstrated that Polycefin was delivered into the tumor cells by a receptor-mediated endocytosis mechanism and was able to inhibit the synthesis of laminin-8 α4 and β1 chains at the same time. Inhibition of laminin-8 expression was in agreement with the designed endosomal membrane disruption and drug releasing activity. In vivo imaging showed the accumulation of intravenously injected Polycefin in brain tumor tissue via the antibody-targeted transferrin receptor-mediated endosomal pathway in addition to a less efficient mechanism known for high molecular mass biopolymers as enhanced permeability and retention effect. Polycefin was nontoxic to normal and tumor astrocytes in a wide range of concentrations, accumulated in brain tumor, and could be used for specific targeting of several biomarkers simultaneously.
PMCID: PMC3487710  PMID: 16536461
17.  Nanoconjugate Platforms Development Based in Poly(β,L-Malic Acid) Methyl Esters for Tumor Drug Delivery 
Journal of nanotechnology  2010;2010:825363.
New copolyesters derived from poly(β,L-malic acid) have been designed to serve as nanoconjugate platforms in drug delivery. 25% and 50% methylated derivatives (coPMLA-Me25H75 and coPMLA-Me50H50) with absolute molecular weights of 32 600 Da and 33 100 Da, hydrodynamic diameters of 3.0 nm and 5.2 nm and zeta potential of −15mV and −8.25mV, respectively, were found to destabilize membranes of liposomes at pH 5.0 and pH 7.5 at concentrations above 0.05mg/mL. The copolymers were soluble in PBS (half life of 40 hours) and in human plasma (half life of 15 hours) but they showed tendency to aggregate at high levels of methylation. Fluorescence-labeled copolymers were internalized into MDA-MB-231 breast cancer cells with increased efficiency for the higher methylated copolymer. Viability of cultured brain and breast cancer cell lines indicated moderate toxicity that increased with methylation. The conclusion of the present work is that partially methylated poly(β,L-malic acid) copolyesters are suitable as nanoconjugate platforms for drug delivery.
PMCID: PMC3459346  PMID: 23024655
18.  Polymalic Acid–Based Nanobiopolymer Provides Efficient Systemic Breast Cancer Treatment by Inhibiting both HER2/neu Receptor Synthesis and Activity 
Cancer research  2011;71(4):1454-1464.
Biodegradable nanopolymers are believed to offer great potential in cancer therapy. Here, we report the characterization of a novel, targeted, nanobiopolymeric conjugate based on biodegradable, nontoxic, and nonimmunogenic PMLA [poly(β-l-malic acid)]. The PMLA nanoplatform was synthesized for repetitive systemic treatments of HER2/neu-positive human breast tumors in a xenogeneic mouse model. Various moieties were covalently attached to PMLA, including a combination of morpholino antisense oligonucleotides (AON) directed against HER2/neu mRNA, to block new HER2/neu receptor synthesis; anti-HER2/neu antibody trastuzumab (Herceptin), to target breast cancer cells and inhibit receptor activity simultaneously; and transferrin receptor antibody, to target the tumor vasculature and mediate delivery of the nanobiopolymer through the host endothelial system. The results of the study showed that the lead drug tested significantly inhibited the growth of HER2/neu-positive breast cancer cells in vitro and in vivo by enhanced apoptosis and inhibition of HER2/neu receptor signaling with suppression of Akt phosphorylation. In vivo imaging analysis and confocal microscopy demonstrated selective accumulation of the nanodrug in tumor cells via an active delivery mechanism. Systemic treatment of human breast tumor-bearing nude mice resulted in more than 90% inhibition of tumor growth and tumor regression, as compared with partial (50%) tumor growth inhibition in mice treated with trastuzumab or AON, either free or attached to PMLA. Our findings offer a preclinical proof of concept for use of the PMLA nanoplatform for combination cancer therapy.
PMCID: PMC3428373  PMID: 21303974
19.  Phase I trial of a multi-epitope-pulsed dendritic cell vaccine for patients with newly diagnosed glioblastoma 
Cancer Immunology, Immunotherapy  2012;62(1):125-135.
This study evaluated the safety and immune responses to an autologous dendritic cell vaccine pulsed with class I peptides from tumor-associated antigens (TAA) expressed on gliomas and overexpressed in their cancer stem cell population (ICT-107).
TAA epitopes included HER2, TRP-2, gp100, MAGE-1, IL13Rα2, and AIM-2. HLA-A1- and/or HLA-A2-positive patients with glioblastoma (GBM) were eligible. Mononuclear cells from leukapheresis were differentiated into dendritic cells, pulsed with TAA peptides, and administered intradermally three times at two-week intervals.
Twenty-one patients were enrolled with 17 newly diagnosed (ND-GBM) and three recurrent GBM patients and one brainstem glioma. Immune response data on 15 newly diagnosed patients showed 33 % responders. TAA expression by qRT-PCR from fresh-frozen tumor samples showed all patient tumors expressed at least three TAA, with 75 % expressing all six. Correlations of increased PFS and OS with quantitative expression of MAGE1 and AIM-2 were observed, and a trend for longer survival was observed with gp100 and HER2 antigens. Target antigens gp100, HER1, and IL13Rα2 were downregulated in recurrent tumors from 4 HLA-A2+ patients. A decrease in or absence of CD133 expression was seen in five patients who underwent a second resection. At a median follow-up of 40.1 months, six of 16 ND-GBM patients showed no evidence of tumor recurrence. Median PFS in newly diagnosed patients was 16.9 months, and median OS was 38.4 months.
Expression of four ICT-107 targeted antigens in the pre-vaccine tumors correlated with prolonged overall survival and PFS in ND-GBM patients. The goal of targeting tumor antigens highly expressed on glioblastoma cancer stem cells is supported by the observation of decreased or absent CD133 expression in the recurrent areas of gadolinium-enhanced tumors.
PMCID: PMC3541928  PMID: 22847020
Dendritic cell immunotherapy; Cancer stem cells; Cancer vaccine; CTL; Epitopes; Glioblastoma
20.  Fluorescence lifetime spectroscopy for guided therapy of brain tumors 
Neuroimage  2010;54(Suppl 1):S125-S135.
PMCID: PMC3335732  PMID: 21055475
glioma; time-resolved fluorescence spectroscopy; in-vivo diagnosis
21.  Loss of PTEN Is Not Associated with Poor Survival in Newly Diagnosed Glioblastoma Patients of the Temozolomide Era 
PLoS ONE  2012;7(3):e33684.
Pre-temozolomide studies demonstrated that loss of the tumor suppressor gene PTEN held independent prognostic significance in GBM patients. We investigated whether loss of PTEN predicted shorter survival in the temozolomide era. The role of PTEN in the PI3K/Akt pathway is also reviewed.
Patients with histologically proven newly diagnosed GBM were identified from a retrospective database between 2007 and 2010. Cox proportional hazards analysis was used to calculate the independent effects of PTEN expression, age, extent of resection, Karnofsky performance scale (KPS), and treatment on overall survival.
Sixty-five percent of patients were men with median age of 63 years, and 70% had KPS≥80. Most patients (81%) received standard treatment (temozolomide with concurrent radiation). A total of 72 (47%) patients had retained PTEN expression. Median overall survival (OS) was 19.1 months (95% CI: 15.0–22.5). Median survival of 20.0 months (95% CI: 15.0–25.5) and 18.2 months (95% CI: 13.0–25.7) was observed in PTEN retained and PTEN loss patients, respectively (p = .71). PTEN loss patients were also found to have amplifications of EGFR gene more frequently than patients with retained PTEN (70.8% vs. 47.8%, p = .01). Multivariate analysis showed that older age (HR 1.64, CI: 1.02–2.63, p = .04), low KPS (HR 3.57, CI: 2.20–5.79, p<.0001), and lack of standard treatment (HR 3.98, CI: 2.38–6.65, p<.0001) yielded worse survival. PTEN loss was not prognostic of overall survival (HR 1.31, CI: 0.85–2.03, p = .22).
Loss of expression of PTEN does not confer poor overall survival in the temozolomide era. These findings imply a complex and non-linear molecular relationship between PTEN, its regulators and effectors in the tumorigenesis of glioblastoma. Additionally, there is evidence that temozolomide may be more effective in eradicating GBM cancer cells with PTEN loss and hence, level the outcomes between the PTEN retained and loss groups.
PMCID: PMC3315579  PMID: 22479427
22.  Nanobiopolymer for Direct Targeting and Inhibition of EGFR Expression in Triple Negative Breast Cancer 
PLoS ONE  2012;7(2):e31070.
Treatment options for triple negative breast cancer (TNBC) are generally limited to cytotoxic chemotherapy. Recently, anti-epidermal growth factor receptor (EGFR) therapy has been introduced for TNBC patients. We engineered a novel nanobioconjugate based on a poly(β-L-malic acid) (PMLA) nanoplatform for TNBC treatment. The nanobioconjugate carries anti-tumor nucleosome-specific monoclonal antibody (mAb) 2C5 to target breast cancer cells, anti-mouse transferrin receptor (TfR) antibody for drug delivery through the host endothelial system, and Morpholino antisense oligonucleotide (AON) to inhibit EGFR synthesis. The nanobioconjugates variants were: (1) P (BioPolymer) with AON, 2C5 and anti-TfR for tumor endothelial and cancer cell targeting, and EGFR suppression (P/AON/2C5/TfR), and (2) P with AON and 2C5 (P/AON/2C5). Controls included (3) P with 2C5 but without AON (P/2C5), (4) PBS, and (5) P with PEG and leucine ester (LOEt) for endosomal escape (P/mPEG/LOEt). Drugs were injected intravenously to MDA-MB-468 TNBC bearing mice. Tissue accumulation of injected nanobioconjugates labeled with Alexa Fluor 680 was examined by Xenogen IVIS 200 (live imaging) and confocal microscopy of tissue sections. Levels of EGFR, phosphorylated and total Akt in tumor samples were detected by western blotting.
In vitro western blot showed that the leading nanobioconjugate P/AON/2C5/TfR inhibited EGFR synthesis significantly better than naked AON. In vivo imaging revealed that 2C5 increased drug-tumor accumulation. Significant tumor growth inhibition was observed in mice treated with the lead nanobioconjugate (1) [P = 0.03 vs. controls; P<0.05 vs. nanobioconjugate variant (2)]. Lead nanobioconjugate (1) also showed stronger inhibition of EGFR expression and Akt phosphorylation than other treatments. Treatment of TNBC with the new nanobioconjugate results in tumor growth arrest by inhibiting EGFR and its downstream signaling intermediate, phosphorylated Akt. The nanobioconjugate represents a new generation of nanodrugs for treatment of TNBC.
PMCID: PMC3280290  PMID: 22355336
23.  Identification of Amyloid Plaques in Retinas from Alzheimer’s Patients and Noninvasive In Vivo Optical Imaging of Retinal Plaques in a Mouse Model 
NeuroImage  2010;54S1:S204-S217.
Noninvasive monitoring of β-amyloid (Aβ) plaques, the neuropathological hallmarks of Alzheimer's disease (AD), is critical for AD diagnosis and prognosis. Current visualization of Aβ plaques in brains of live patients and animal models is limited in specificity and resolution. The retina as an extension of the brain portrays an appealing target for a live, noninvasive optical imaging of AD if disease pathology is manifested there. We identified retinal Aβ plaques in postmortem eyes from AD patients (n=8) and in suspected early stage cases (n=5), consistent with brain pathology and clinical reports; plaques were undetectable in age-matched non-AD individuals (n=5). In APPSWE/PS1ΔE9 transgenic mice (AD-Tg; n=18) and not in non-Tg wt mice (n=10), retinal Aβ plaques were detected following systemic administration of curcumin, a safe plaque-labeling fluorochrome. Moreover, retinal plaques were detectable earlier than in the brain and accumulated with disease progression. An immune-based therapy effective in reducing brain plaques, significantly reduced retinal Aβ plaque burden in immunized versus non-immunized AD mice (n=4 mice per group). In live AD-Tg mice (n=24), systemic administration of curcumin allowed noninvasive optical imaging of retinal Aβ plaques in vivo with high resolution and specificity; plaques were undetectable in non-Tg wt mice (n=11). Our discovery of Aβ specific plaques in retinas from AD patients, and the ability to noninvasively detect individual retinal plaques in live AD mice establish the basis for developing high resolution optical imaging for early AD diagnosis, prognosis assessment and response to therapies.
PMCID: PMC2991559  PMID: 20550967
human retina; Aβ deposit; Aβ plaque; Alzheimer’s disease; mild cognitive impairment; vaccination; curcumin; in vivo optical imaging; fluorescence; spectral classification
24.  Cellular Delivery of Doxorubicin via pH-Controlled Hydrazone Linkage Using Multifunctional Nano Vehicle Based on Poly(β-L-Malic Acid) 
Doxorubicin (DOX) is currently used in cancer chemotherapy to treat many tumors and shows improved delivery, reduced toxicity and higher treatment efficacy when being part of nanoscale delivery systems. However, a major drawback remains its toxicity to healthy tissue and the development of multi-drug resistance during prolonged treatment. This is why in our work we aimed to improve DOX delivery and reduce the toxicity by chemical conjugation with a new nanoplatform based on polymalic acid. For delivery into recipient cancer cells, DOX was conjugated via pH-sensitive hydrazone linkage along with polyethylene glycol (PEG) to a biodegradable, non-toxic and non-immunogenic nanoconjugate platform: poly(β-l-malic acid) (PMLA). DOX-nanoconjugates were found stable under physiological conditions and shown to successfully inhibit in vitro cancer cell growth of several invasive breast carcinoma cell lines such as MDA-MB-231 and MDA-MB- 468 and of primary glioma cell lines such as U87MG and U251.
PMCID: PMC3472769  PMID: 23109877
polymalic acid; doxorubicin; nanoconjugate; pH-controlled hydrazine linkage; brain and breast cancer
25.  CTGF Associated with Oncogenic Activities and Drug Resistance in Glioblastoma Multiforme (GBM) 
Connective tissue growth factor (CTGF or CCN2) is a secreted protein that belongs to the CCN [cysteine-rich CYR61/connective tissue growth factor/nephroblastoma overexpressed gene] family. These proteins have been implicated in various biological processes, including stimulation of cell proliferation, migration, angiogenesis and tumorigenesis. In a previous study, we found that CTGF mRNA was elevated in primary gliomas and a significant correlation existed between CTGF mRNA levels versus tumor grade, histology, and patient survival. In the present study, the role of CTGF in glioma tumorigenesis was explored. Forced expression of CTGF in glioblastoma multiforme (GBM) cells accelerated their growth in liquid culture and soft agar, stimulated cells migration in Boyden chamber assays and significantly increased their ability to form large, vascularized tumors in nude mice. CTGF induced the expression of the anti-apoptotic proteins, Bcl-xl, Survivin, and Flip. Over-expression of CTGF caused the U343 GBM cells to survive for longer than 40 days in serum-free medium and resist anti-tumor drugs including tumor necrosis factor (TNF), TNF-related apoptosis-inducing ligand (TRAIL), VELCADE (Bortezomib, Proteasome Inhibitor), and Temozolomide. Our data suggest that CTGF plays an important role in glioma progression, by supporting tumor cells survival and drug resistance.
PMCID: PMC2946420  PMID: 20162579
CTGF; CCN; Drug resistance; Glioblastoma Multiforme (GBM)

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