Clinical Advances in Triple Negative Breast Cancer Treatment: Focus on Poly (L-lactide-coglycolide) Nanoparticles.

Triple negative breast cancer (TNBC) is the most aggressive type of breast cancer and is associated with high probability of metastasis and poor prognosis. Chemotherapeutics and surgery remain the most common options for TNBC patients; however, chemotherapeutic resistance and relapse of tumors limit the progression free survival and patient life span. This review provides an overview of recent chemotherapeutics that are in clinical trial, and the combination of drugs that are being investigated to overcome the drug resistance and to improve patient survival in different molecular subtypes of TNBCs. Nanotherapeutics have emerged as a promising platform for TNBC treatment and aim to improve the selectivity and solubility of drugs, reduce systemic side effects, and overcome multi-drug resistance. The study explores the role of nanoparticles for TNBC treatment and summarizes the types of nanoparticles that are in clinical trials. Poly(L-lactide-co-glycolide) (PLGA) is the most studied polymeric carrier for drug delivery and for TNBC treatment in research and in clinics. This review is about providing recent advancements in PLGA nanotherapeutic formulations and their application to help treat TNBC. Some background on current chemotherapies and pathway inhibitors is provided so that the readers are aware of what is currently considered for TNBC. Some of the pathway inhibitors may also be of importance for nanotherapeutics development. SIGNIFICANCE STATEMENT: This minireview summarizes the progress on chemotherapeutics and nanoparticle delivery for treatment of TNBC and specifically highlights the lead compounds that are in clinical trials.

A tale of two multi-focal therapies for glioblastoma: An antibody targeting ELTD1 and nitrone-based OKN-007.

Glioblastoma (GBM) is the most common primary malignant brain tumour in adults. Despite a multimodal treatment response, survival for GBM patients remains between 12 and 15 months. Anti-ELTD1 antibody therapy is effective in decreasing tumour volumes and increasing animal survival in an orthotopic GBM xenograft. OKN-007 is a promising chemotherapeutic agent that is effective in various GBM animal models and is currently in two clinical trials. In this study, we sought to compare anti-ELTD1 and OKN-007 therapies, as single agents and combined, against bevacizumab, a commonly used therapeutic agent against GBM, in a human G55 xenograft mouse model. MRI was used to monitor tumour growth, and immunohistochemistry (IHC) was used to assess tumour markers for angiogenesis, cell migration and proliferation in the various treatment groups. OKN and anti-ELTD1 treatments significantly increased animal survival, reduced tumour volumes and normalized the vasculature. Additionally, anti-ELTD1 was also shown to significantly affect other pro-angiogenic factors such as Notch1 and VEGFR2. Unlike bevacizumab, anti-ELTD1 and OKN treatments did not induce a pro-migratory phenotype within the tumours. Anti-ELTD1 treatment was shown to be as effective as OKN therapy. Both OKN and anti-ELTD1 therapies show promise as potential single-agent multi-focal therapies for GBM patients.

Physical Forces in Glioblastoma Migration: A Systematic Review.

The invasive capabilities of glioblastoma (GBM) define the cancer's aggressiveness, treatment resistance, and overall mortality. The tumor microenvironment influences the molecular behavior of cells, both epigenetically and genetically. Current forces being studied include properties of the extracellular matrix (ECM), such as stiffness and "sensing" capabilities. There is currently limited data on the physical forces in GBM-both relating to how they influence their environment and how their environment influences them. This review outlines the advances that have been made in the field. It is our hope that further investigation of the physical forces involved in GBM will highlight new therapeutic options and increase patient survival. A search of the PubMed database was conducted through to 23 March 2022 with the following search terms: (glioblastoma) AND (physical forces OR pressure OR shear forces OR compression OR tension OR torsion) AND (migration OR invasion). Our review yielded 11 external/applied/mechanical forces and 2 tumor microenvironment (TME) forces that affect the ability of GBM to locally migrate and invade. Both external forces and forces within the tumor microenvironment have been implicated in GBM migration, invasion, and treatment resistance. We endorse further research in this area to target the physical forces affecting the migration and invasion of GBM.

Effect of engineered superparamagnetic iron oxide nanoparticles in targeted cardiac precursor cell delivery by MRI.

A scientific approach is presented describing the fabrication of nanoprobe (GloTrack) that can act as cardiac precursor label to segregate cells from cardiac/non cardiac origins and traced by magnetic resonance imaging (MRI). Signal regulatory protein alpha (SIRPA) and kinase domain receptor (KDR) recognizing antibodies, form a layer on super paramagnetic iron oxide nanoparticle - poly-ethylene glycol (SPION-PEG) complex, and bind to protein expressed on the surface of cardiac muscle cells. Physical attributes size, distribution, labelling efficiency, echocardiogram (ECG) changes and bio-distribution by MRI were analysed. The results indicate that GloTrack has an average size of 471 nm, exhibits negative potential and promotes labelling efficiency. The bio-distribution of GloTrack in in vivo experiments was traceable in 7T MRI showing high accumulation of GloTrack in cardiac muscles as compared to the liver and spleen. ECG data revealed that GloTrack segregated cardiac precursors has the potential benefit in treating heart failure, thereby paving way in the development of minimal cell manipulation with targeted cell delivery approaches.

Optimized monoclonal antibody treatment against ELTD1 for GBM in a G55 xenograft mouse model.

Glioblastoma is an aggressive brain tumour found in adults, and the therapeutic approaches available have not significantly increased patient survival. Recently, we discovered that ELTD1, an angiogenic biomarker, is highly expressed in human gliomas. Polyclonal anti-ELTD1 treatments were effective in glioma pre-clinical models, however, pAb binding is potentially promiscuous. Therefore, the aim of this study was to determine the effects of an optimized monoclonal anti-ELTD1 treatment in G55 xenograft glioma models. MRI was used to assess the effects of the treatments on animal survival, tumour volumes, perfusion rates and binding specificity. Immunohistochemistry and histology were conducted to confirm and characterize microvessel density and Notch1 levels, and to locate the molecular probes. RNA-sequencing was used to analyse the effects of the mAb treatment. Our monoclonal anti-ELTD1 treatment significantly increased animal survival, reduced tumour volumes, normalized the vasculature and showed higher binding specificity within the tumour compared with both control- and polyclonal-treated mice. Notch1 positivity staining and RNA-seq results suggested that ELTD1 has the ability to interact with and interrupt Notch1 signalling. Although little is known about ELTD1, particularly about its ligand and pathways, our data suggest that our monoclonal anti-ELTD1 antibody is a promising anti-angiogenic therapeutic in glioblastomas.

OKlahoma Nitrone-007: novel treatment for diffuse intrinsic pontine glioma.

BACKGROUND: Diffuse intrinsic pontine glioma (DIPG) is the most common brainstem cancer in childhood. This rapidly progressing brainstem glioma holds a very dismal prognosis with median survival of less than 1 year. Despite extensive research, no significant therapeutic advancements have been made to improve overall survival in DIPG patients. METHODS: Here, we used an orthotopic xenograft pediatric DIPG (HSJD-DIPG-007) mouse model to monitor the effects of anti-cancer agent, OKlahoma Nitrone-007 (OKN-007), as an inhibitor of tumor growth after 28 days of treatment. Using magnetic resonance imaging (MRI), we confirmed the previously described efficacy of LDN-193189, a known activin A receptor, type I (ACVR1) inhibitor, in decreasing tumor burden and found that OKN-007 was equally efficacious. RESULTS: After 28 days of treatment, the tumor volumes were significantly decreased in OKN-007 treated mice (p < 0.01). The apparent diffusion coefficient (ADC), as a measure of tissue structural alterations, was significantly decreased in OKN-007 treated tumor-bearing mice (p < 0.0001). Histological analysis also showed a significant decrease in CD34 expression, essential for angiogenesis, of OKN-007 treated mice (p < 0.05) compared to LDN-193189 treated mice. OKN-007-treated mice also significantly decreased protein expression of the human nuclear antigen (HNA) (p < 0.001), ACVR1 (p < 0.0001), and c-MET (p < 0.05), as well as significantly increased expression of cleaved caspase 3 (p < 0.001) and histone H3 K27-trimethylation (p < 0.01), compared to untreated mouse tumors. CONCLUSIONS: With the dismal prognosis and limited effective chemotherapy available for DIPG, there is significant room for continued research studies, and OKN-007 merits further exploration as a therapeutic agent.

Analysis of retention of gadolinium by brain, bone, and blood following linear gadolinium-based contrast agent administration in rats with experimental sepsis.

PURPOSE: It is important to identify populations that may be vulnerable to the brain deposition of gadolinium (Gd) from MRI contrast agents. At intervals from 24 hours to 6 weeks following injection of a linear Gd contrast agent, the brain, blood and bone content of Gd were compared between control rats and those with experimental endotoxin-induced sepsis that results in neuroinflammation and blood-brain barrier disruption. METHODS: Male rats were injected intraperitoneally with 10 mg/kg lipopolysaccharide. Control animals received no injection. Twenty-four hours later, 0.2 mmol/kg of gadobenate dimeglumine was injected intravenously. Brain, blood, and bone Gd levels were measured at 24 hours, 1 week, 3 weeks, and 6 weeks by inductively coupled plasma mass spectroscopy. RESULTS: Blood Gd decreased rapidly between 24 hours and 1 week, and thereafter was undetectable, with no significant difference between lipopolysaccharide and control rats. Brain levels of Gd were significantly higher (4.29-2.36-fold) and bone levels slightly higher (1.35-1.11-fold) in lipopolysaccharide than control rats at all time points with significant retention at 6 weeks. CONCLUSION: Experimental sepsis results in significantly higher deposition of Gd in the brain and bone in rats. While blood Gd clears rapidly, brain and bone retained substantial Gd even at 6 weeks following contrast injection.

Epstein Barr virus nuclear antigen 1 (EBNA-1) peptides recognized by adult multiple sclerosis patient sera induce neurologic symptoms in a murine model.

Multiple sclerosis (MS) is an autoimmune demyelinating disease with progressive neurodegeneration and complex etiology likely involving genetic and environmental factors. MS has been associated with Epstein Barr virus (EBV) infection, with patients often showing enhanced responses to EBV antigens. To determine whether abnormal EBV nuclear antigen-1 (EBNA-1) humoral immunity can serve as an initiator of autoimmune responses in MS, we investigated the fine specificities of the humoral immune response against EBNA-1 in MS patients using solid phase epitope mapping. Antibodies from MS patients recognized an EBNA-1 epitope spanning amino acids 411-426, previously unknown to be recognized specifically by untreated MS patients. Antibodies against this epitope cross-reacted to myelin basic protein (MBP). Furthermore, animals immunized with this EBNA-1 polypeptide mounted a response against MBP and developed signs of experimental autoimmune encephalitis (EAE). These data support a link between MS and EBV through antibodies that cross-react between EBV proteins and the MBP autoantigen.

Immunologically modified MnFe2O4 nanoparticles to synergize photothermal therapy and immunotherapy for cancer treatment.

Immunotherapy has been a promising candidate for cancer treatment. The combination of photothermal therapy (PTT) and immunotherapy have shown to cause tumor ablation and induce host immune response. However, this strategy is often hampered by a limited immune response and undesirable immunosuppression. In this work, we developed an immunologically modified nanoplatform, using ovalbumin (OVA)-coated PEGylated MnFe2O4 nanoparticles (NPs) loaded with R837 immunoadjuvant (R837-OVA-PEG-MnFe2O4 NPs) to synergize PTT and immunotherapy for the treatment of breast cancer. The designed R837-OVA-PEG-MnFe2O4 NPs are able to elicit significant immune responses in vitro and in vivo. MnFe2O4 NPs also allowed for a reduction of systemic immunosuppression through downregulation of M2-associated cytokines. More importantly, the R837-OVA-PEG-MnFe2O4 NPs under laser irradiation effectively inhibited tumor growth and prevented lung metastases, leading to a prolonged survival time and improved survival rate. In addition, the designed multitasking MnFe2O4 NPs showed as a good contrast agent for magnetic resonance (MR) imaging to detect orthotopic breast tumor in vivo. Our work provides a novel strategy for combined PTT and improved immunotherapy in the treatment of breast and other metastatic cancers.

Therapeutic efficacy of a synthetic epsin mimetic peptide in glioma tumor model: uncovering multiple mechanisms beyond the VEGF-associated tumor angiogenesis.

Binding of epsin ubiquitin-interacting motif (UIM) with ubiquitylated VEGFR2 is a critical mechanism for epsin-dependent VEGFR2 endocytosis and physiological angiogenesis. Deletion of epsins in vessel endothelium produces uncontrolled tumor angiogenesis and retards tumor growth in animal models. The aim of this study is to test the therapeutic efficacy and targeting specificity of a chemically-synthesized peptide, UPI, which compete for epsin binding sites in VEGFR2 and potentially inhibits Epsin-VEGFR2 interaction in vivo, in an attempt to reproduce an epsin-deficient phenotype in tumor angiogenesis. Our data show that UPI treatment significantly inhibits and shrinks tumor growth in GL261 glioma tumor model. UPI peptide specifically targets VEGFR2 signaling pathway revealed by genetic and biochemical approaches. Furthermore, we demonstrated that UPI peptide treatment caused serious thrombosis in tumor vessels and damages tumor cells after a long-term UPI peptide administration. Besides, we revealed that UPI peptides were unexpectedly targeted cancer cells and induced apoptosis. We conclude that UPI peptide is a potent inhibitor to glioma tumor growth through specific targeting of VEGFR2 signaling in the tumor vasculature and cancer cells, which may offer a potentially novel treatment for cancer patients who are resistant to current anti-VEGF therapies.

In the absence of overt urothelial damage, chondroitinase ABC digestion of the GAG layer increases bladder permeability in ovariectomized female rats.

Loss of integrity of the protective impermeability barrier in the urothelium has been identified as significant in bladder dysfunction. In this study, we tested the theory that the luminal layer of glycosaminoglycans (GAG) serves as an important component of barrier function. The peptide polycation protamine sulfate (PS), 1 mg/ml, was instilled intravesically for 10 min into rat bladders. Chondroitinase ABC (ChABC), 63 IU/ml, was instilled into an additional six rats for 30 min to digest the GAG layer. Unmanipulated controls and sham-injected controls were also performed. After 24 h, the rats were euthanized, the bladders were removed, and permeability was assessed in the Ussing chamber and by diffusion of FITC-labeled dextran (4 kDa) to measure macromolecular permeability. The status of tight junctions was assessed by immunofluorescence and electron microscopy. In control and sham treated rat bladders, the transepithelial electrical resistance were means of 2.5 ± 1.1 vs. 2.6 ± 1.1 vs 1.2 ± 0.5 and 1.01 ± 0.7 kΩ·cm(2) in the PS-treated and ChABC-treated rat bladders (P = 0.0016 and P = 0.0039, respectively). Similar differences were seen in dextran permeability. Histopathology showed a mild inflammation following PS treatment, but the ChABC-treated bladders were indistinguishable from controls. Tight junctions generally remained intact. ChABC digestion alone induced bladder permeability, confirming the importance of the GAG layer to bladder barrier function and supports that loss of the GAG layer seen in bladder biopsies of interstitial cystitis patients could be a significant factor producing symptoms for at least some interstitial cystitis/painful bladder syndrome patients.

A Feasibility Study to Determine Whether Clinical Contrast Enhanced Magnetic Resonance Imaging can Detect Increased Bladder Permeability in Patients with Interstitial Cystitis.

PURPOSE: Interstitial cystitis/bladder pain syndrome is a bladder pain disorder associated with voiding symptomatology and other systemic chronic pain disorders. Currently diagnosing interstitial cystitis/bladder pain syndrome is complicated as patients present with a wide range of symptoms, physical examination findings and clinical test responses. One hypothesis is that interstitial cystitis symptoms arise from increased bladder permeability to urine solutes. This study establishes the feasibility of using contrast enhanced magnetic resonance imaging to quantify bladder permeability in patients with interstitial cystitis. MATERIALS AND METHODS: Permeability alterations in bladder urothelium were assessed by intravesical administration of the magnetic resonance imaging contrast agent Gd-DTPA (Gd-diethylenetriaminepentaacetic acid) in a small cohort of patients. Magnetic resonance imaging signal intensity in patient and control bladders was compared regionally and for entire bladders. RESULTS: Quantitative assessment of magnetic resonance imaging signal intensity indicated a significant increase in signal intensity in anterior bladder regions compared to posterior regions in patients with interstitial cystitis (p <0.01) and significant increases in signal intensity in anterior bladder regions (p <0.001). Kurtosis (shape of probability distribution) and skewness (measure of probability distribution asymmetry) were associated with contrast enhancement in total bladders in patients with interstitial cystitis vs controls (p <0.05). Regarding symptomatology interstitial cystitis cases differed significantly from controls on the SF-36®, PUF (Pelvic Pain and Urgency/Frequency) and ICPI (Interstitial Cystitis Problem Index) questionnaires with no overlap in the score range in each group. ICSI (Interstitial Cystitis Symptom Index) differed significantly but with a slight overlap in the range of scores. CONCLUSIONS: Data suggest that contrast enhanced magnetic resonance imaging provides an objective, quantifiable measurement of bladder permeability that could be used to stratify bladder pain patients and monitor therapy.

Up-regulation of the Sirtuin 1 (Sirt1) and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) genes in white adipose tissue of Id1 protein-deficient mice: implications in the protection against diet and age-induced glucose intolerance.

Id1, a helix-loop-helix (HLH) protein that inhibits the function of basic HLH E protein transcription factors in lymphoid cells, has been implicated in diet- and age-induced obesity by unknown mechanisms. Here we show that Id1-deficient mice are resistant to a high fat diet- and age-induced obesity, as revealed by reduced weight gain and body fat, increased lipid oxidation, attenuated hepatosteatosis, lower levels of lipid droplets in brown adipose tissue, and smaller white adipocytes after a high fat diet feeding or in aged animals. Id1 deficiency improves glucose tolerance, lowers serum insulin levels, and reduces TNFα gene expression in white adipose tissue. Id1 deficiency also increased expression of Sirtuin 1 and peroxisome proliferator-activated receptor γ coactivator 1α, regulators of mitochondrial biogenesis and energy expenditure, in the white adipose tissue. This effect was accompanied by the elevation of several genes encoding proteins involved in oxidative phosphorylation and fatty acid oxidation, such as cytochrome c, medium-chain acyl-CoA dehydrogenase, and adipocyte protein 2. Moreover, the phenotype for Id1 deficiency was similar to that of mice expressing an E protein dominant-positive construct, ET2, suggesting that the balance between Id and E proteins plays a role in regulating lipid metabolism and insulin sensitivity.

Immuno-spin trapping from biochemistry to medicine: advances, challenges, and pitfalls. Focus on protein-centered radicals.

BACKGROUND: Immuno-spin trapping (IST) is based on the reaction of a spin trap with a free radical to form a stable nitrone adduct, followed by the use of antibodies, rather than traditional electron paramagnetic resonance spectroscopy, to detect the nitrone adduct. IST has been successfully applied to mechanistic in vitro studies, and recently, macromolecule-centered radicals have been detected in models of drug-induced agranulocytosis, hepatotoxicity, cardiotoxicity, and ischemia/reperfusion, as well as in models of neurological, metabolic and immunological diseases. SCOPE OF THE REVIEW: To critically evaluate advances, challenges, and pitfalls as well as the scientific opportunities of IST as applied to the study of protein-centered free radicals generated in stressed organelles, cells, tissues and animal models of disease and exposure. MAJOR CONCLUSIONS: Because the spin trap has to be present at high enough concentrations in the microenvironment where the radical is formed, the possible effects of the spin trap on gene expression, metabolism and cell physiology have to be considered in the use of IST and in the interpretation of results. These factors have not yet been thoroughly dealt with in the literature. GENERAL SIGNIFICANCE: The identification of radicalized proteins during cell/tissue response to stressors will help define their role in the complex cellular response to stressors and pathogenesis; however, the fidelity of spin trapping/immuno-detection and the effects of the spin trap on the biological system should be considered. This article is part of a Special Issue entitled Current methods to study reactive oxygen species - pros and cons and biophysics of membrane proteins. Guest Editor: Christine Winterbourn.

Mechanisms of Visceral Organ Crosstalk: Importance of Alterations in Permeability in Rodent Models.

PURPOSE: The pathophysiology of painful bladder syndrome is poorly understood. However, there is evidence of female predominance and comorbidity with irritable bowel syndrome. Our hypothesis is that cross-sensitization between bladder and colon is due to altered permeability in 1 organ, which affects the other organ. MATERIALS AND METHODS: Experiments were performed in anesthetized, ovariectomized female rats. In separate groups protamine sulfate was infused in the bladder or trinitrobenzene sulfonic acid was infused in the colon. Untreated rats served as controls. Bladder and colonic tissue were harvested from all rats 1, 3 and 5 days after treatment. Permeability was assessed in vitro in Ussing chambers by measuring transepithelial electrical resistance and macromolecular flux of fluorescein isothiocyanate-dextran. RESULTS: Exposing the bladder to protamine sulfate induced a significant decrease in bladder transepithelial electrical resistance and an increase in the translocation of fluorescein isothiocyanate across the tissue compared to controls at 1 and 3 days (p <0.05). Colonic tissue from rats with enhanced bladder permeability showed a significant decrease in transepithelial electrical resistance and increase in fluorescein isothiocyanate compared to untreated controls at all time points (p <0.05). Conversely when colonic permeability was increased with trinitrobenzene sulfonic acid, we observed an increase in bladder permeability in the absence of any changes to the bladder urothelium. CONCLUSIONS: Changes in epithelial permeability may represent a novel mechanism for visceral organ crosstalk. It may explain the overlapping symptomology of painful bladder syndrome and irritable bowel syndrome.

Contrast enhanced magnetic resonance imaging as a diagnostic tool to assess bladder permeability and associated colon cross talk: preclinical studies in a rat model.

PURPOSE: Interstitial cystitis/painful bladder syndrome is a devastating disease associated with multiple symptoms. It is usually diagnosed based on pain, urgency and frequency in the absence of other known causes. To our knowledge there is no diagnostic test to date. MATERIALS AND METHODS: In a model of rats intravesically exposed to protamine sulfate we performed in vivo diagnostic contrast enhanced magnetic resonance imaging with intravesical administration of Gd-diethylenetriamine pentaacetic acid contrast medium via a catheter to visualize increased bladder urothelium permeability. Gd-diethylenetriamine pentaacetic acid was administered intravenously to visualize secondary tissue effects in the colon. RESULTS: Bladder urothelium and colon mucosa were assessed 24 hours after bladder protamine sulfate exposure. Enhanced contrast magnetic resonance imaging established bladder urothelium leakage of Gd-diethylenetriamine pentaacetic acid according to the change in magnetic resonance imaging signal intensity in rats exposed to protamine sulfate vs controls (mean ± SD 399.7% ± 68.7% vs 39.2% ± 12.2%, p < 0.0001) as well as colon related uptake of contrast agent (mean 65.2% ± 17.1% vs 20.8% ± 9.8%, p < 0.01) after bladder protamine sulfate exposure. The kinetics of Gd-diethylenetriamine pentaacetic acid uptake and excretion were also assessed during 20 minutes of bladder and 30 minutes of colon exposure with increased signal intensity at 7 and 12 minutes, respectively. CONCLUSIONS: These preliminary studies indicate that contrast enhanced magnetic resonance imaging can be used to monitor primary bladder urothelium loss of permeability and secondary enhanced contrast medium in the colon mucosa. It can be considered a potential clinical diagnostic method for interstitial cystitis/painful bladder syndrome that involves loss of the permeability barrier. It can also be used to assess visceral organ cross talk.

A new anti-glioma therapy, AG119: pre-clinical assessment in a mouse GL261 glioma model.

BACKGROUND: High grade gliomas (HGGs; grades III and IV) are the most common primary brain tumors in adults, and their malignant nature ranks them fourth in incidence of cancer death. Standard treatment for glioblastomas (GBM), involving surgical resection followed by radiation and chemotherapy with temozolomide (TMZ) and the anti-angiogenic therapy bevacizumab, have not substantially improved overall survival. New therapeutic agents are desperately needed for this devastating disease. Here we study the potential therapeutic agent AG119 in a pre-clinical model for gliomas. AG119 possesses both anti-angiogenic (RTK inhibition) and antimicrotubule cytotoxic activity in a single molecule. METHODS: GL261 glioma-bearing mice were either treated with AG119, anti-VEGF (vascular endothelial growth factor) antibody, anti c-Met antibody or TMZ, and compared to untreated tumor-bearing mice. Animal survival was assessed, and tumor volumes and vascular alterations were monitored with morphological magnetic resonance imaging (MRI) and perfusion-weighted imaging, respectively. RESULTS: Percent survival of GL261 HGG-bearing mice treated with AG119 was significantly higher (p < 0.001) compared to untreated tumors. Tumor volumes (21-31 days following intracerebral implantation of GL261 cells) were found to be significantly lower for AG119 (p < 0.001), anti-VEGF (p < 0.05) and anti-c-Met (p < 0.001) antibody treatments, and TMZ-treated (p < 0.05) mice, compared to untreated controls. Perfusion data indicated that both AG119 and TMZ were able to reduce the effect of decreasing perfusion rates significantly (p < 0.05 for both), when compared to untreated tumors. It was also found that IC50 values for AG119 were much lower than those for TMZ in T98G and U251 cells. CONCLUSIONS: These data support further exploration of the anticancer activity AG119 in HGG, as this compound was able to increase animal survival and decrease tumor volumes in a mouse GL261 glioma model, and that AG119 is also not subject to methyl guanine transferase (MGMT) mediated resistance, as is the case with TMZ, indicating that AG119 may be potentially useful in treating resistant gliomas.

OKN-007 decreases tumor necrosis and tumor cell proliferation and increases apoptosis in a preclinical F98 rat glioma model.

BACKGROUND: Glioblastoma is a malignant World Health Organization (WHO) grade IV glioma with a poor prognosis in humans. New therapeutics are desperately required. The nitrone OKN-007 (2,4-disulfophenyl-PBN) has demonstrated effective anti-glioma properties in several rodent models and is currently being used as a clinical investigational drug for recurrent gliomas. We assessed the regional effects of OKN-007 in the tumor necrotic core and non-necrotic tumor parenchyma. METHODS: An F98 rat glioma model was evaluated using proton magnetic resonance spectroscopy ((1) H-MRS), diffusion-weighted imaging (DWI), morphological T2-weighted imaging (T2W) at 7 Tesla (30 cm-bore MRI), as well as immunohistochemistry and microarray assessments, at maximum tumor volumes (15-23 days following cell implantation in untreated (UT) tumors, and 18-35 days in OKN-007-treated tumors). RESULTS: (1) H-MRS data indicates that Lip0.9/Cho, Lip0.9/Cr, Lip1.3/Cho, and Lip1.3/Cr ratios are significantly decreased (all P < 0.05) in the OKN-007-treated group compared with UT F98 gliomas. The Cho/Cr ratio is also significantly decreased in the OKN-007-treated group compared with UT gliomas. In addition, the OKN-007-treated group demonstrates significantly lower ADC values in the necrotic tumor core and the nonnecrotic tumor parenchyma (both P < 0.05) compared with the UT group. There was also an increase in apoptosis following OKN-007 treatment (P < 0.01) compared with UT. CONCLUSION: OKN-007 reduces both necrosis and tumor cell proliferation, as well as seems to mediate multiple effects in different tumor regions (tumor necrotic core and nonnecrotic tumor parenchyma) in F98 gliomas, indicating the efficacy of OKN-007 as an anti-cancer agent and its potential clinical use.

Combined molecular MRI and immuno-spin-trapping for in vivo detection of free radicals in orthotopic mouse GL261 gliomas.

Free radicals play a major role in gliomas. By combining immuno-spin-trapping (IST) and molecular magnetic resonance imaging (mMRI), in vivo levels of free radicals were detected within mice bearing orthotopic GL261 gliomas. The nitrone spin trap DMPO (5,5-dimethyl pyrroline N-oxide) was administered prior to injection of an anti-DMPO probe (anti-DMPO antibody covalently bound to a bovine serum albumin (BSA)-Gd (gadolinium)-DTPA (diethylene triamine penta acetic acid)-biotin MRI contrast agent) to trap tumor-associated free radicals. mMRI detected the presence of anti-DMPO adducts by either a significant sustained increase (p<0.001) in MR signal intensity or a significant decrease (p<0.001) in T1 relaxation, measured as %T1 change. In vitro assessment of the anti-DMPO probe indicated a significant decrease (p<0.0001) in T1 relaxation in GL261 cells that were oxidatively stressed with hydrogen peroxide, compared to controls. The biotin moiety of the anti-DMPO probe was targeted with fluorescently-labeled streptavidin to locate the anti-DMPO probe in excised brain tissues. As a negative control a non-specific IgG antibody covalently bound to the albumin-Gd-DTPA-biotin construct was used. DMPO adducts were also confirmed in tumor tissue from animals administered DMPO, compared to non-tumor brain tissue. GL261 gliomas were found to have significantly increased malondialdehyde (MDA) protein adducts (p<0.001) and 3-nitrotyrosine (3-NT) (p<0.05) compared to normal mouse brain tissue, indicating increased oxidized lipids and proteins, respectively. Co-localization of the anti-DMPO probe with either 3-NT or 4-hydroxynonenal was also observed. This is the first report regarding the detection of in vivo levels of free radicals from a glioma model.