CN-105 in Participants with Acute Supratentorial Intracerebral Hemorrhage (CATCH) Trial

BACKGROUND

Endogenous apolipoprotein (apo) E mediates neuroinflammatory responses and recovery after brain injury. Exogenously administered apoE-mimetic peptides effectively penetrate the central nervous system compartment and downregulate acute inflammation. CN-105 is a novel apoE-mimetic pentapeptide with excellent evidence of functional and histological improvement in preclinical models of intracerebral hemorrhage (ICH). The CN-105 in participants with Acute supraTentorial intraCerebral Hemorrhage (CATCH) trial is a first-in-disease-state multicenter open-label trial evaluating safety and feasability of CN-105 administration in patients with acute primary supratentorial ICH.

METHODS

Eligible patients were aged 30-80 years, had confirmed primary supratentorial ICH, and were able to intiate CN-105 administration (1.0 mg/kg every 6 h for 72 h) within 12 h of symptom onset. A priori defined safety end points, including hematoma volume, pharmacokinetics, and 30-day neurological outcomes, were analyzed. For clinical outcomes, CATCH participants were compared 1:1 with a closely matched contemporary ICH cohort through random selection. Hematoma volumes determined from computed tomography images on days 0, 1, 2, and 5 and ordinal modified Rankin Scale score at 30 days after ICH were compared.

RESULTS

In 38 participants enrolled across six study sites in the United States, adverse events occurred at an expected rate without increase in hematoma expansion or neurological deterioration. CN-105 treatment had an odds ratio (95% confidence interval) of 2.69 (1.31-5.51) for lower 30-day modified Rankin Scale score, after adjustment for ICH score, sex, and race/ethnicity, as compared with a matched contemporary cohort.

CONCLUSIONS

CN-105 administration represents an excellent translational candidate for treatment of acute ICH because of its safety, dosing feasibility, favorable pharmacokinetics, and possible improvement in neurological recovery.

ABC Transporter Inhibition Plus Dexamethasone Enhances the Efficacy of Convection Enhanced Delivery in H3.3K27M Mutant Diffuse Intrinsic Pontine Glioma

BACKGROUND

An impermeable blood-brain barrier and drug efflux via ATP-binding cassette (ABC) transporters such as p-glycoprotein may contribute to underwhelming efficacy of peripherally delivered agents to treat diffuse intrinsic pontine glioma (DIPG).

OBJECTIVE

To explore the pharmacological augmentation of convection-enhanced delivery (CED) infusate for DIPG.

METHODS

The efficacy of CED dasatinib, a tyrosine kinase inhibitor, in a transgenic H3.3K27M mutant murine model was assessed. mRNA expression of ABCB1 (p-glycoprotein) was analyzed in 14 tumor types in 274 children. In Vitro viability studies of dasatinib, the p-glycoprotein inhibitor, tariquidar, and dexamethasone were performed in 2 H3.3K27M mutant cell lines. Magnetic resonance imaging (MRI) was used to evaluate CED infusate (gadolinium/dasatinib) distribution in animals pretreated with tariquidar and dexamethasone. Histological assessment of apoptosis was performed.

RESULTS

Continuous delivery CED dasatinib improved median overall survival (OS) of animals harboring DIPG in comparison to vehicle (39.5 and 28.5 d, respectively; P = .0139). Mean ABCB1 expression was highest in K27M gliomas. In Vitro, the addition of tariquidar and dexamethasone further enhanced the efficacy of dasatinib (P < .001). In Vivo, MRI demonstrated no difference in infusion dispersion between animals pretreated with dexamethasone plus tariquidar prior to CED dasatinib compared to the CED dasatinib. However, tumor apoptosis was the highest in the pretreatment group (P < .001). Correspondingly, median OS was longer in the pretreatment group (49 d) than the dasatinib alone group (39 d) and no treatment controls (31.5 d, P = .0305).

CONCLUSION

ABC transporter inhibition plus dexamethasone enhances the efficacy of CED dasatinib, resulting in enhanced tumor cellular apoptosis and improved survival in H3.3K27M mutant DIPG.

The role of angiogenesis in Group 3 medulloblastoma pathogenesis and survival

Background

Of the 4 medulloblastoma subgroups, Group 3 is the most aggressive but the importance of angiogenesis is unknown. This study sought to determine the role of angiogenesis and identify clinically relevant biomarkers of tumor vascularity and survival in Group 3 medulloblastoma.

Methods

VEGFA mRNA expression and survival from several patient cohorts were analyzed. Group 3 xenografts were implanted intracranially in nude rats. Dynamic susceptibility weighted (DSC) MRI and susceptibility weighted imaging (SWI) were obtained. DSC MRI was used to calculate relative cerebral blood volume (rCBV) and flow (rCBF). Tumor vessel density and rat vascular endothelial growth factor alpha (VEGFA) expression were determined.

Results

Patient VEGFA mRNA levels were significantly elevated in Group 3 compared with the other subgroups (P < 0.001) and associated with survival. Xenografts D283, D341, and D425 were identified as Group 3 by RNA hierarchical clustering and MYC amplification. The D283 group had the lowest rCBV and rCBF, followed by D341 and D425 (P < 0.05). These values corresponded to histological vessel density (P < 0.05), rat VEGFA expression (P < 0.05), and survival (P = 0.002). Gene set enrichment analysis identified 5 putative genes with expression profiles corresponding with these findings: RNH1, SCG2, VEGFA, AGGF1, and PROK2. SWI identified 3 xenograft-independent categories of intratumoral vascular architecture with distinct survival (P = 0.004): organized, diffuse microvascular, and heterogeneous.

Conclusions

Angiogenesis plays an important role in Group 3 medulloblastoma pathogenesis and survival. DSC MRI and SWI are clinically relevant biomarkers for tumor vascularity and overall survival and can be used to direct the use of antivascular therapies for patients with Group 3 medulloblastoma.

Mn porphyrins as novel molecular magnetic resonance imaging contrast agents

BACKGROUND AND PURPOSE

In this study, we investigated the potential of a new class of therapeutic Mn porphyrins as molecular MRI probes for prostate cancer imaging. Two compounds of different bioavailibility were investigated: Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5+)) and Mn(III) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (MnTnHex-2-PyP(5+)). These compounds have previously been shown to have adjunctive antineoplastic activity through their actions as powerful superoxide dismutase mimics, peroxynitrite scavengers, and modulators of cellular redox-based signaling pathways. Strong paramagnetic MRI contrast properties and affinity for cancer cells suggest their potential application as novel diagnostic imaging agents.

MATERIALS AND METHODS

MRI experiments were performed at 7.0T on a Bruker Biospec horizontal bore scanner. All in-vivo experiments were performed on 12 C57 black mice implanted with RM-9 prostate cancer cells on the hind limb. Two mg/kg of MnTnHex-2-PyP(5+) (n=6) and 8 mg/kg MnTE-2-PyP(5+) (n=6) were administered intraperitoneally 90 minutes before imaging. All the images were collected using a volume coil and processed using Paravision 4.0.

RESULTS

Phantom studies reveal remarkably high T1 relaxivity changes for both metalloporphyrins, which are twofold to threefold higher than commercially available gadolinium chelates. Observable detection limits using conventional T1-weighted MRI are in the low micromolar range for both compounds. In vivo, MR relaxation changes in prostate tumor xenografts were readily observed after a single injection of either MnTE-2-PyP(5+)or MnTnHex-2-PyP(5+), with tumor contrast to background ratio greatest after MnTE-2-PyP(5+) administration.

CONCLUSION

After a single dose of MnTE-2-PyP(5+), contrast changes in prostate tumors are up to sixfold greater than in surrounding, noncancerous tissues, suggesting the potential use of this metalloporphyrin as a novel diagnostic probe for detecting prostate malignancy using MRI.

Synthesis and preliminary evaluation of n.c.a. iodoquine: a novel radiotracer with high uptake in cells with high ALDH1 expression

PURPOSE

Chloroquine has demonstrated high affinity for aldehyde dehydrogenase 1A1 (ALDH1), an enzyme expressed in the highly tumorigenic CD133+ brain tumor initiating subpopulation. The purpose of this study is to report the novel synthesis of a chloroquine analogue, n.c.a. iodoquine, and the in vitro and in vivo uptake in cells with high ALDH1 content.

METHODS AND MATERIALS

Iodoquine was synthesized in novel no-carrier-added forms (n.c.a.) for both 125I and 123I. I25I IQ and 18F FDG cell uptake assays were performed in the L1210 and L1210cpa (cyclophosphamide resistant), A549, and MG456 glioblastoma cell lines. Uptake was expressed as a percent of the administered activity. 125I IQ biodistribution studies assessed organ uptake at 1, 4, and 24 hours after IV administration (n= 15 total; 5 mice/timepoint). Radiation dosimetry estimates were calculated using standard OLINDA/EXM software. In vivo imaging of 123I IQ uptake in MG456 glioblastoma mouse model (n=10) was performed with small animal high resolution micro-SPECT. Autoradiography and histology co-localized radiotracer and tumor biodistribution. Uptake in MG456 glioblastoma tumors was quantified with gamma counting.

RESULTS

L1210 cpa (high ALDH1) showed significantly higher 125I IQ uptake compared to the parental L1210 (low ALDH1) for all time points through 4 hours (20.7% ± 1.4% versus 11.0% ± 0.5%; 21.3% ± 0.9% versus 11.0% ± 0.4%; 20.6% ± 0.7% versus 9.4% ± 0.3%; and 15.7% ± 0.7% versus 7.5% + 0.4% at 30 minutes, and 1, 2 and 4 hours, respectively; p < 0.001 for all time points). In the CD133+ fraction of MG456 glioblastoma cell line, IQ uptake was significantly higher compared to FDG at all time points through 4 hours (81.5% ± 0.9% versus 1.3% ± 0.1%; 88.8% ± 0.4% versus 1.3% ± 0.1%; 87.8% ± 2.1% versus 1.7% ± 0.2%; and 87.0% ± 2.4% versus 1.8% ± 0.1 at 30 minutes, and 1, 2 and 4 hours, respectively; p > 0.001 for all time points). The A549 lung cancer cell line also showed high IQ uptake through 4 hours. IQ normal biodistribution studies showed rapid renal excretion and very low normal background brain activity after IV administration. In vivo micro-SPECT images showed mild uptake in larger MG456 glioblastomas (n=6) as verified with autoradiography and histology. Gamma well counter uptake in large tumors was 2.3% ± 0.48% ID/g (n=5).

CONCLUSION

Iodoquine localizes to cells with high ALDH1 content. Cell assays show high 125I IQ uptake in the MG456 cell line, and in vivo micro-SPECT imaging showed mild 123I IQ uptake in MG456 glioblastomas. Further studies are necessary to investigate 131I IQ as a potential therapeutic agent targeting the highly tumorigenic CD133+ brain tumor stem cell subpopulation.

Mn-porphyrins as novel molecular magnetic resonance imaging contrast agents

BACKGROUND AND PURPOSE

In this study, we investigated the potential of a new class of therapeutic Mn porphyrins as molecular MRI probes for prostate cancer imaging. Two compounds of different bioavailibility were investigated: Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5 +)) and Mn(III) mesotetrakis(N-n-hexylpyridinium-2-yl)porphyrin (MnTnHex-2-PyP(5 +)). These compounds have previously been shown to have adjunctive antineoplastic activity through their actions as powerful superoxide dismutase mimics, peroxynitrite scavengers, and modulators of cellular redox-based signaling pathways. Strong paramagnetic MRI contrast properties and affinity for cancer cells suggest their potential application as novel diagnostic imaging agents.

MATERIALS AND METHODS

MRI experiments were performed at 7.0T on a Bruker Biospec horizontal bore scanner. All in-vivo experiments were performed on 12 C57 black mice implanted with RM-9 prostate cancer cells on the hind limb. Two mg/kg of MnTnHex-2-PyP(5 +) (n = 6) and 8 mg/kg MnTE-2-PyP(5 +) (n = 6) were administered intraperitoneally 90 minutes before imaging. All the images were collected using a volume coil and processed using Paravision 4.0.

RESULTS

Phantom studies reveal remarkably high T1 relaxivity changes for both metalloporphyrins, which are twofold to threefold higher than commercially available gadolinium chelates. Observable detection limits using conventional T1-weighted MRI are in the low micromolar range for both compounds. In vivo, MR relaxation changes in prostate tumor xenografts were readily observed after a single injection of either MnTE-2-PyP(5 +) or MnTnHex-2-PyP(5 +), with tumor contrast to background ratio greatest after MnTE-2-PyP(5 +) administration.

CONCLUSION

After a single dose of MnTE-2-PyP(5 +), contrast changes in prostate tumors are up to sixfold greater than in surrounding, noncancerous tissues, suggesting the potential use of this metalloporphyrin as a novel diagnostic probe for detecting prostate malignancy using MRI.

Hedgehog signaling antagonist promotes regression of both liver fibrosis and hepatocellular carcinoma in a murine model of primary liver cancer

OBJECTIVE

Chronic fibrosing liver injury is a major risk factor for hepatocarcinogenesis in humans. Mice with targeted deletion of Mdr2 (the murine ortholog of MDR3) develop chronic fibrosing liver injury. Hepatocellular carcinoma (HCC) emerges spontaneously in such mice by 50-60 weeks of age, providing a model of fibrosis-associated hepatocarcinogenesis. We used Mdr2(-/-) mice to investigate the hypothesis that activation of the hedgehog (Hh) signaling pathway promotes development of both liver fibrosis and HCC.

METHODS

Hepatic injury and fibrosis, Hh pathway activation, and liver progenitor populations were compared in Mdr2(-/-) mice and age-matched wild type controls. A dose finding experiment with the Hh signaling antagonist GDC-0449 was performed to optimize Hh pathway inhibition. Mice were then treated with GDC-0449 or vehicle for 9 days, and effects on liver fibrosis and tumor burden were assessed by immunohistochemistry, qRT-PCR, Western blot, and magnetic resonance imaging.

RESULTS

Unlike controls, Mdr2(-/-) mice consistently expressed Hh ligands and progressively accumulated Hh-responsive liver myofibroblasts and progenitors with age. Treatment of aged Mdr2-deficient mice with GDC-0449 significantly inhibited hepatic Hh activity, decreased liver myofibroblasts and progenitors, reduced liver fibrosis, promoted regression of intra-hepatic HCCs, and decreased the number of metastatic HCC without increasing mortality.

CONCLUSIONS

Hh pathway activation promotes liver fibrosis and hepatocarcinogenesis, and inhibiting Hh signaling safely reverses both processes even when fibrosis and HCC are advanced.

Molecular imaging in Alzheimer's disease

Molecular imaging represents a new term for a long-standing quest to image cellular and molecular processes in vivo. The development of a successful molecular imaging approach starts with a well-defined diagnostic question best answered using in vivo imaging. A selective target for a particular disease state is then identified and a biocompatible probe selective for that target is developed. Many of the challenges of finding selective disease targets and probes that bind selectively to those targets in vivo are evident in the 25-year history of molecular imaging in Alzheimer's disease. This article provides a brief overview of molecular imaging in Alzheimer's disease and its potential for early diagnosis and treatment development.

Astroglial acid-base dynamics in hyperglycemic and normoglycemic global ischemia

Biochemical, histological, and physiological evidence suggest strongly that astrocytes may either defend or damage brain tissue, depending on the brain carbohydrate content preceding global ischemia (28,43). This paper will first review the concept of acidosis in ischemia and the possible role of severe, compartmentalized astrocytic acidosis in pan necrosis. Results are then presented demonstrating that astrocytes are also capable of maintaining an alkaline intracellular pH (pHi) during normoglycemic global ischemia. Mechanisms underlying depolarization-dependent astroglial alkalosis are then reviewed. Recent experiments indicate that bicarbonate (HCO3-) transport is a major mechanism by which astroglia not only alkalinize their interior but also acidify the interstitium. Maintenance of alkalosis during normoglycemic ischemia supports the hypothesis that astroglial HCO3- transport might ultimately protect neurons from excitotoxicity in ischemia without infarction (17). Inhibition of astroglial HCO3- transport may be a critical and requisite event, ultimately leading to compartmentalized astroglial acidosis and irreversible injury to all cell types.

Interferon-gamma and tumour necrosis factor induce expression of major histocompatibility complex antigen on rat retinal astrocytes

Cultured rat retinal astrocytes were tested by indirect immunofluorescence staining for their ability to express class I and II major histocompatibility complex (MHC) antigens under basal culture conditions and after three days of stimulation with two recombinant cytokines, rat interferon-gamma (IFN-gamma) and human tumour necrosis factor alpha (TNF alpha). Under basal culture conditions low levels of class I antigens were detected on a small percentage of cells, but there was no visible class II. IFN-gamma and TNF alpha stimulation enhanced class I expression. TNF alpha had no effect on class II expression, whereas IFN-gamma induced the expression of class II in a dose dependent manner. These findings suggest that retinal astrocytes might play a part in immunological events occurring in the retina.