Previous Midlife Oestradiol Treatment Results in Long-Term Maintenance of Hippocampal Oestrogen Receptor α Levels in Ovariectomised Rats: Mechanisms and Implications for Memory

Ovariectomised rats that have received previous administration of oestradiol in midlife display enhanced cognition and increased hippocampal levels of oestrogen receptor (ER)α months after oestradiol treatment ended compared to ovariectomised controls. The present study aimed to investigate the mechanisms by which ERα levels are maintained following midlife oestradiol exposure and the role of ERα in memory in ageing females in the absence of circulating oestrogens. Unliganded ERα has increased interaction with the ubiquitin ligase, C-terminus of Hsc-70 interacting protein (CHIP), leading to increased degradation of the receptor. In our first experiment, we tested the hypothesis that midlife oestradiol exposure in ovariectomised rats results in decreased interaction between CHIP and hippocampal ERα, leading to increased levels of ERα. Middle-aged rats were ovariectomised and received oestradiol or vehicle implants. After 40 days, implants were removed. One month later, rats were killed and hippocampi were processed for whole protein western blotting and co-immunoprecipitation, in which ERα was immunoprecipitated from lysate. As expected, ERα protein expression was increased in rats previously treated with oestradiol compared to vehicle-treated rats. In rats treated with oestradiol, there was a decrease in CHIP-ERα interaction, suggesting that previous oestradiol treatment reduces interaction, slowing the degradation of ERα. In a second experiment, we determined the impact on memory of antagonism of ER in the absence of circulating oestrogens. Rats were ovariectomised and implanted with oestradiol capsules. Capsules were removed after 40 days. Rats received chronic i.c.v. infusion of ER antagonist, ICI 182 780, or artificial cerebrospinal fluid vehicle and were tested on a spatial memory radial-maze task. Rats treated with ICI 182 780 had significantly worse performance (more errors). These experiments provide evidence that previous midlife oestradiol treatment maintains hippocampal ERα by decreasing its interaction with CHIP and that activation of these receptors provides cognitive benefits in the absence of circulating oestrogens.

Histochemical evaluation of energy metabolism in rat glioma

The key enzymes of oxidative phosphorylation and glycolysis were evaluated histochemically in rat-implanted C6 gliomas using spot densitometry. Hexokinase, the initial enzyme for the glycolysis pathway, was 40% higher within tumour than the contralateral cerebral cortex. A similar increase within tumours for 2-deoxyglucose was observed by autoradiography. Glucose-6-phosphate dehydrogenase (G6PDH), which is the first enzyme in the pentose phosphate pathway, shunting glucose towards nucleic acid synthesis, was more than 300% higher in gliomas compared with the normal cortex. In contrast, enzymes in the energy producing tricarboxylic acid cycle (succinate-, isocitrate-, and malate-dehydrogenase) and in the electron-transport system (cytochrome c oxidase) were significantly reduced in tumour (58% less than the contralateral cortex). Lactate dehydrogenase activity, which converts pyruvate to lactate, was 50% higher within tumour. Significant reductions of enzymatic activities also occurred in non-neoplastic tissue in ipsilateral hemisphere, with larger tumours. Some enzymes showed heterogeneous activity within tumours, especially G6PDH. These results suggest that: (1) energy production is more dependent on lactate production than on oxidative phosphorylation in C6 glioma, and (2) a significant part of the increased glucose utilization in glioma cells is due to increased activity of the pentose phosphate shunt for increased DNA synthesis, and not energy production.

Abstract A50: Nanobiocojugates of differential imaging and treatment of brain metastatic tumors

Introduction: A significant clinical problem with brain metastatic (BM) tumors is drug delivery and diagnostic imaging to verify MRI enhancement(s) for planning treatment. MRI enhancement in cancer patient's brain might result from infection after chemotherapy that impairs immune system; metastasis from primary lung/breast cancer; or a new primary brain tumor. Unlike lung/breast, brain biopsies are often technically impossible. Therefore, there is urgent need for the development of effective theranostic (dual therapy and diagnostic) systems against brain metastatic cancer.

Most chemotherapeutic drugs or therapeutic monoclonal antibodies (mAb), Trastuzumab, Cetuximab, and Rituximab, are effective for primary tumor treatment but cannot penetrate blood brain barrier (BBB) failing to treat brain metastasis.

We used a natural nanobiopolymer, polymalic acid (PMLA), as a nanoplatform for the family of tumor-targeted PolycefinTM drugs to provide differential brain tumor imaging and treatment.

Methods: Three xenogeneic orthotropic human brain metastatic tumors, MDA-MB-474, HER2+ breast cancer; A549 lung cancer, and MDA-MB-468, triple negative breast cancer (TNBC), both EGFR+, were inoculated stereotactically into the brain of mice.

For diagnostic imaging, PolycefinTM was used with covalently attached MRI tracer Gadolinium (Gd-DOTA). Morpholino antisense oligonucleotides (AON) were conjugated to PolycefinTM to specifically inhibit gene/protein expression to block tumor growth. The combination of cell surface targeting mAbs, including anti-transferrin receptor (TfR) mAb for drug BBB transcytosis, and AONs to multiple tumor markers on the same delivery polymer was used for anti-tumor treatment.

MRI 1H imaging was performed on a 9.4-Tesla small animal MRI system. Treatment groups of animals included (1) HER2+ MDA-MB-474 breast cancer metastases targeted with PMLA-Gd-DOTA/HER2 mAb/TfR mAb; (2) EGFR+ MDA-MB-468 TNBC metastases targeted with PMLA-Gd-DOTA/EGFR mAb/TfR mAb; and (3) Controls for all treatments inoculated with PMLA-IgG mAb and clinical Gd.

Unpublished Results. Imaging: Dynamic T1 analysis. Similar data for specific tumor imaging were obtained for brain-implanted lung and breast tumors: the inverse of T1-1 relaxation time (proportional to Gd concentration) was measured in healthy brain part and in the tumor. T1-1 time dependence for Gd-DOTA-Polycefin (T1-1 ratio tumor/normal brain) was compared with clinically used Gd MRI agent, MultiHance®. After reaching a maximum, high T1-1 relative values prevailed for several hours for Gd-DOTA-mAb-Polycefin, but declined rapidly for Gd. High contrast for Gd was seen in 20 min, whereas that for Gd-DOTA-Polycefin peaked in 45-60 min, and remained for up to 3 hrs. By differential MRI with anti-HER2 (Trastuzumab) or anti-EFGR (Cetuximab) mAb attached covalently to the nanoplatform, we were able to differentiate HER2+ from EGFR+ metastatic brain tumors with corresponding imaging controls.

Treatment: Animal survival after Polycefin treatment of various brain metastases was significantly higher than in untreated (PBS) or therapeutic mAb (Herceptin or Cetuximab) treated animals. These survival increases were as follows: 66% for lung cancer metastasis, 47% for HER2+ breast cancer metastasis, and 81% for TNBC metastasis.

Conclusions. We have developed a system for differential imaging and treatment of various metastatic brain tumors based on specific metastasis targeting, and inhibition of expression of tumor-specific genes/proteins. Systemic treatment with this system resulted in significantly increased survival of brain metastatic tumor-bearing animals.

Citation Format: Julia Y. Ljubimova, R. Patil, P. Gangalum, S. Wagner, S. Inoue, H. Ding, J. Portilla, K. Rekechenetskiy, K. Bindu, J. Markman, A. Chesnokova, K. L. Black, E. Holler. Nanobiocojugates of differential imaging and treatment of brain metastatic tumors. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr A50.

A phase I trial of surgical resection with biodegradable carmustine (BCNU) wafer placement followed by vaccination with dendritic cells pulsed with tumor lysate for patients with malignant glioma

2033

Background: Our prior immunotherapy trials demonstrated efficacy in generating a tumor specific immune response in malignant glioma and the potential for high tumor-specific toxicity and sustained tumoricidal activity. Immunotherapy may synergize with chemotherapy and biodegradable carmustine (BCNU) wafers extend overall survival from 11.6 to 13.9 months. Methods: We exploited this synergistic effect to maintain a cytotoxic environment around the tumor milieu. Patients with high-grade glioma were eligible after maximal resection with biodegradable carmustine (BCNU) wafer placement. Screening leukapheresis is used to isolate mononuclear cells which are differentiated into dendritic cells, pulsed with tumor lysate, and then 3 intradermal vaccines are administered at 2-week intervals. Patients continued systemic chemotherapy after vaccine or at progression. Results: Eighteen patients have been enrolled (7 Male, 11 Female) between April 2007 and February 2009 with one screen failure and two patients with clinical progression prior to vaccination. The median patient age was 57 years (26 to 74 ) and median Karnofsky performance status was 90% (80–100). The histology included 3 newly diagnosed glioblastoma multiforme (GBM), 8 recurrent GBM, 2 newly diagnosed anaplastic astrocytoma (AA), and 2 recurrent AA. 15 patients were successfully treated by vaccine injections with 12 patients receiving vaccine every 2 weeks x 3 followed by adjuvant chemotherapy. Our preliminary data on 15 patients and 39 courses of Dendritic Cell vaccines demonstrate one grade 3 toxicity of fever/chest pain. A stable disease interval of 13 to 90 weeks was observed for patients who received vaccine. The 3 newly diagnosed GBM patients have stable disease (18 to 71 weeks). In the recurrent GBM cohort 7/8 patients had progression within 6 months from the post-vaccination MRI. Conclusions: This phase I study demonstrates the safety, feasibility of dendritic cell vaccination with biodegradable carmustine (BCNU) wafers with one grade 3 AE. Immunological data is pending to determine potential synergy of dendritic cell vaccination with intracranial chemotherapy.

No significant financial relationships to disclose.

Novel uses of insulin syringes to reduce dosing errors: a retrospective chart review of enoxaparin whole milligram dosing

Enoxaparin is a low molecular weight heparin (LMWH) commonly used for thromboprophylaxis children. Enoxaparin dosing is based on patients' weight and results in decimal dosing. Due to the high concentration of enoxaparin the resultant decimal dose makes precise measurement difficult. Dilution is necessary and often results in ten-fold medication administration errors [Ghaleb MA, Barber N, Franklin BD, Yeung VWS, Khaki ZF, Wong ICK. Systematic review of medication errors in pediatric patients. Ann Pharmacother Oct 2006;40(10):1766-76, Raju TN, Kecskes S, Thornton JP, Perry M, Feldman S. Medication errors in neonatal and paediatric intensive-care units. Lancet Aug 12 1989;2(8659):374-6]. Enoxaparin may be administered in whole milligram doses via insulin syringe, where one milligram of enoxaparin equals one unit on the 100 unit graduated insulin syringe.

STUDY DESIGN

A retrospective chart review of 514 children. Data was collected on underlying diagnosis, reason for anticoagulation, anti-Xa levels, hemorrhagic events, and medication errors identified.

OUTCOME

to determine the occurrence rate of supra-therapeutic anticoagulation as indicated by anti-Xa levels >1.0 u/ml, when enoxaparin doses are rounded up to the whole milligram, and are administered using insulin syringes. The secondary objectives were to determine if the supra-therapeutic anti-Xa levels were associated with hemorrhagic events. To determine if children achieved and maintained therapeutic anti-Xa range using whole milligram dosing and to evaluate the impact of utilizing insulin syringes for administration on reducing dose measurement errors.

RESULTS

All 514 patients were prescribed whole milligram enoxaparin dosing, and achieved therapeutic anti-Xa within a mean time of 2 days. No infant or child required decimal doses to achieve therapeutic levels. Five children achieved an initial supra-therapeutic anti-Xa level (1.04 -1.36 U/ml), requiring a single whole milligram dose decrease. There were no associated hemorrhagic events.

CONCLUSION

Whole milligram enoxaparin dosing administered via an insulin syringe safely and effectively, achieved therapeutic levels in infants and children. The reduced incidence of enoxaparin dosing errors suggests that whole milligram enoxaparin dosing via an insulin syringe is a method that should be considered for standard of care.

DLK1: increased expression in gliomas and associated with oncogenic activities

DLK1 (delta-like) is a transmembrane and secreted protein in the epidermal growth factor-like homeotic family. Although expressed widely during embryonic development, only a few tissues retain the expression in adults. Neuroendocrine tumors often highly express this protein; therefore, we hypothesized that brain tumors might also express it. This study found that the expression of DLK1 in gliomas was higher than that in normal brain (P < 0.05). After stable transfection of a DLK1 cDNA expression vector into GBM cell lines, their proliferation was increased. Furthermore, they lost contact inhibition, had enhanced anchorage-independent growth in soft agar, and had significantly greater capacity to migrate. Western blot studies showed that expression of cyclin D1, CDK2, and E2F4 were increased, and Rb levels were decreased in these cells. DLK1 was found on the cell surface and secreted in the medium from the transfected GBM cells. DLK1-enriched condition medium stimulated the growth of glioblastoma multiforme cell lines and explants. DLK1 antibody blocked cell growth stimulated by DLK1. In summary, these results suggest that DLK1 may play a role in the formation or progression of gliomas.

Innovative cancer vaccine strategies based on the identification of tumour-associated antigens

The identification of tumour-associated antigens has opened up new approaches to cancer immunotherapy. While past research focused on CD8+ cytotoxic T-cell responses, accumulating evidence suggests that CD4+ T cells also play an important role in orchestrating the host immune response against cancer. In this article, we summarise new strategies for the identification of major histocompatibility complex (MHC) class II-associated tumour antigens and discuss the importance of engaging both CD4+ and CD8+ T cells in cancer immunotherapy. The cloning of MHC class I- or class II-associated antigens has made it possible to develop synthetic and recombinant cancer vaccines that express specific tumour antigens. There are three major types of synthetic and recombinant cancer vaccines: recombinant viral and bacterial vaccines; naked DNA or RNA vaccines; and recombinant protein and peptide vaccines. In this article, we also discuss a new generation of recombinant cancer vaccines, 'self-replicating' DNA and RNA vaccines. Studies on the mechanisms of 'self-replicating' nucleic acid vaccines revealed that the enhanced immunogenicity was not due to an enhanced antigen expression, suggesting that the quantitative difference may not be as important as the qualitative difference in antigen presentation. The presence of the RNA replicase in the 'self-replicating' nucleic acid vaccines mimics alphavirus infection, which triggers the innate antiviral pathways of the host cells. Studies on how viral and cellular modulators of the innate antiviral pathways affect vaccine function should provide molecular insights crucial to future vaccine design.

Repeated, short-term ischemia augments bradykinin-mediated opening of the blood-tumor barrier in rats with RG2 glioma

The objective of this study was to investigate the effects of repeated, short-term ischemia on bradykinin-mediated permeability of the blood-brain barrier (BBB) and the blood-tumor barrier (BTB). The mechanism by which bradykinin transiently opens the BTB, involves B2 receptors, Ca2+ flux, nitric oxide (NO) and cyclic GMP (cGMP). Since global and focal cerebral ischemia are known to increase levels of brain nitric oxide synthase (bNOS) and endothelial nitric oxide synthase (eNOS) we tested the hypothesis that bradykinin may increase the BTB permeability to a greater extent under ischemic rather than nonischemic conditions. The vertebral arteries in female Wistar rats were coagulated immediately after intracerebral implantation of RG2 glioma. Short-term ischemia was produced in some rats by a modification of the four-vessel occlusion procedure for incomplete forebrain ischemia, in which the common carotid arteries were clamped daily for 15 min on days 7, 8 and 9 after tumor implantation, after which reperfusion was allowed. On day 10 after tumor implantation, bradykinin (10 microg kg(-1) min(-1)) or phosphate-buffered saline (PBS) was infused for 15 min into the right carotid artery of anesthetized, sham-operated (nonischemic controls) and ischemic rats, followed by an intravenous bolus (100 microCi kg(-1)) each of [14C]-iodo-antipyrine (IAP), [14C]-dextran or [14C]-aminoisobutyric acid (AIB) to measure regional cerebral blood flow (rCBF), blood volume, or unidirectional transfer constant Ki, respectively, by quantitative autoradiography. A single 15-min ischemic episode significantly decreased rCBF in the tumor center (158.9 +/- 17.33 in control vs. 58.78 +/- 24.45 ml 100 g(-1) min(-1) in ischemic group; p < 0.01) and in the tumor periphery (106.82 +/- 7.34 in control vs. 70.55 +/- 26.66 ml 100 g(-1) min(-1) in ischemic group; p < 0.05). Respective mean blood volume in tumors (11.7 +/- 13.3, 12.7 +/- 14.0, and 13.3 +/- 14.5 microl g(-1)) from ischemic-PBS, nonischemic-bradykinin, and ischemic-bradykinin groups, respectively, was not significantly different; mean blood volume in normal brain (3.7, 3.1 and 3.8 microl g(-1)) was not significantly different among these groups either. Intracarotid infusion of bradykinin following repeated ischemia significantly increased mean Ki, as compared to bradykinin infusion in nonischemic controls, in both the tumor center (36.60 +/- 8.4 vs. 22.90 +/- 4.61 microl g(-1) min(-1), p < 0.05) and in tumor periphery (17.70 +/- 5.93 vs. 8.50 +/- 4.42 microl g(-1) min(-1), p < 0.05). Mean Ki values for tumor center and tumor periphery of ischemic rats receiving intracarotid bradykinin were 3-fold greater than those of nonischemic rats infused with PBS. Immunohistochemical and Western blot analyses showed that repeated, short-term ischemia significantly increased the levels of bNOS in tumor cells and eNOS in tumor capillaries, but neither induced iNOS nor affected B2 receptor levels in tumor cells in vivo, as compared with nonischemic controls. Taken together, these results demonstrate for the first time that repeated, short-term ischemia augments bradykinin-mediated opening of the BTB. We conclude that the elevated intratumoral levels of bNOS and eNOS may 'prime' the NO generating capacity of tumor cells. Consequently, increased de novo synthesis and a correspondingly elevated concentration of NO within the tumor, therefore, may be one mechanistic explanation for the significantly increased, bradykinin-mediated BTB opening under ischemic conditions, reported here.

Overexpression of alpha4 chain-containing laminins in human glial tumors identified by gene microarray analysis

Differential gene expression in tumors often involves growth factors and extracellular matrix/basement membrane components. Here, 11,000- gene microarray was used to identify gene expression profiles in brain tumors including high-grade gliomas [glioblastoma multiforme (GBM) and anaplastic astrocytoma], low-grade astrocytomas, or benign extra-axial brain tumors (meningioma) in comparison with normal brain tissue. Histologically normal tissues adjacent to GBMs were also studied. All GBMs studied overexpressed 14 known genes compared with normal human brain tissue. Overexpressed genes belonged to two broad groups: (a) growth factor-related genes; and (b) structural/extracellular matrix-related genes. For most of these 14 genes, expression levels were lower in low-grade astrocytoma than in GBM and were barely detectable in normal brain. Despite normal-appearing histology, gene expression patterns of tissues immediately adjacent to GBM were similar to those of their respective primary GBMs. Two genes were consistently up-regulated in both high-grade and low-grade gliomas, as well as in histologically normal tissues adjacent to GBMs. These genes coded for the epidermal growth factor receptor (previously reported to be overexpressed in gliomas) and for the alpha4 chain of laminin, a major blood vessel basement membrane component. Changes in expression of this laminin chain have not been previously associated with malignant tumors. Overexpression of laminin alpha4 chain in GBM and astrocytoma grade II by gene microarray analysis was confirmed by semiquantitive reverse transcription-PCR and immunohistochemistry. Importantly, an alpha4 chain-containing laminin isoform, laminin-8 (alpha4beta1gamma1), was expressed mainly in blood vessel walls of GBMs and histologically normal tissues adjacent to GBMs, whereas another alpha4 chain-containing laminin isoform, laminin-9 (alpha4beta2gamma1), was expressed mainly in blood vessel walls of low-grade tumors and normal brain. GBMs that overexpressed laminin-8 had a shorter mean time to tumor recurrence (4.3 months) than GBMs with overexpression of laminin-9 (9.7 months, P = 0.0007). Up-regulation of alpha4 chain-containing laminins could be important for the development of glioma-induced neovascularization and glial tumor progression. Overexpression of laminin-8 may be predictive of glioma recurrence.

Modified immunoregulation associated with interferon-gamma treatment of rat glioma

Little is known about modulation by cytokines of major histocompatibility complex (MHC) antigen expression on intracranial tumors in vivo. The ability of cytokines to up-regulate MHC class-1 (MHC-1) antigen expression was investigated first in vitro using three rat glioma cell lines. Immunohistochemistry showed that incubation with recombinant rat interferon-gamma (rrIFN-gamma) increased MHC-1 antigen expression in RG2, C6, and 9L cell lines. Flow cytometric analysis revealed different baseline levels of MHC-1 antigen expression in each line (RG2 lowest, C6 highest), and that these levels increased in all lines after stimulation with 100 U ml(-1) or more of rrIFN-gamma. The antitumor effect of rrIFN-gamma in vivo was evaluated by assessing survival of rats with implanted intracerebral RG2 gliomas after intracarotid infusion of rrIFN-gamma. A high dose of rrIFN-gamma (2.4 x 10(5) U kg(-1)) significantly increased the survival, compared to control (p < 0.02). Intracarotid pre-treatment with the bradykinin analogue RMP-7 did not further increase survival. Immunohistochemical staining of tumor sections after in vivo rrIFN-gamma, infusion showed no clear increase in MHC-1 antigen expression on tumor cells but increased staining for ED2 antigen within tumor tissue, presumably from perivascular cells with MHC class-2 antigen.

Correlation between bradykinin-induced blood-tumor barrier permeability and B2 receptor expression in experimental brain tumors

Localization of B2 receptors in brain tumor cells and microvessel endothelial cells of the brain tumors was investigated to study the differential sensitivity of brain tumors to bradykinin. The present study shows that B2 receptor expression levels vary in cultured RG2, C6 and 9L glioma cells as well as in the intracerebral tumors established with these cell lines in rats. The double immunohistochemical data indicate that B2 receptors are localized to tumor cells and not to the tumor capillaries. Immunostaining and Western blot analysis for B2 receptor showed that the B2 receptor expression was in the order C6 > RG2 > 9L. The permeability studies on RG2, C6 and 9L tumors in rats showed that C6 tumor had the highest increase (178%) in Ki (unidirectional transport across blood-brain barrier (BBB)/blood-tumor barrier (BTB)), while 9L tumor had the least increase of Ki (35%) over the control group, following intracarotid infusion of bradykinin. We found a positive correlation (r = 0.965, p < 0.001) between B2 receptor levels and bradykinin-induced increase in BTB permeability. We conclude that B2 receptors are localized to tumor cells and not to normal or tumor capillary endothelial cells. C6 tumor with highest B2 receptor expression was most responsive to bradykinin, while RG2 and 9L tumors with lower B2 receptor expression level were less sensitive to bradykinin with regard to BTB permeability.

A herpes simplex virus type 1 mutant deleted for gamma34.5 and LAT kills glioma cells in vitro and is inhibited for in vivo reactivation

To create an oncolytic herpes simplex virus type 1 (HSV-1) that is inhibited for reactivation, we constructed a novel herpes recombinant virus with deletions in the gamma34.5 and LAT genes. The LAT gene was replaced by the gene for green fluorescent protein, thereby allowing viral infection to be followed. This virus, designated DM33, is effective in killing primary and established human glioma cell lines in culture. DM33 is considerably less virulent following intracerebral inoculation of HSV-susceptible BALB/c mice than the wild-type HSV-1 strain McKrae. The safety of this virus is further supported by the retention of its sensitivity to ganciclovir and its relatively limited toxicity against cultured human neuronal cells, astrocytes, and endothelial cells. The ability of DM33 to spontaneously reactivate was tested in a rabbit ocular infection model that accurately depicts human herpes infection and reactivation. Following ocular infection of rabbits, spontaneous reactivation was detected in 83% (15/18) of the eyes infected with wild-type McKrae. In contrast, none of the eyes infected with DM33 had detectable reactivation. The efficacy of this virus in cultured human glioma cell lines, its safety, confirmed by its inability to reactivate, and its attenuated neurovirulence make DM33 a promising oncolytic agent for tumor therapy.

Gene expression abnormalities in human glial tumors identified by gene array

Novel genes specific for human oligodendroglioma and glioblastoma multiforme (GBM) were detected using the gene array analysis [18,376 genes Gene Discovery Array (GDA) from Incyte Genomics, Inc.]. Eleven genes were chosen based on the highest ratios of differential expression identified by GDA between histologically normal adjacent tissue and brain tumor tissue. The differential expression of those 11 genes was verified by semiquantitative RT-PCR and Northern analysis on 22 samples of glial and other tumors of the brain, as well as of normal embryonic and adult brain tissue. Gene no. 5 (an EST) was more expressed by GDA analysis in histologically normal adjacent brain tissue than in the corresponding oligodendroglioma. By RT-PCR, this gene was expressed in a number of brain tumors but not in normal adult and embryonic brain. By GDA analysis, gene no. 7 (oligophrenin-1) gave the highest ratio compared to other genes in brain tissue adjacent to the GBM vs. GBM. By RT-PCR, oligophrenin-1 was expressed in tumors and tumor-adjacent tissue, whereas meningioma and corpus callosum were negative. Gene no. 11 (an EST) was expressed only in brain tumors but not in normal brain by Northern analysis (message size 1.5 kb) and RT-PCR. GDA analysis successfully identified genes preferentially expressed in brain tumors, which was confirmed by Northern analysis and semiquantitative RT-PCR. The validity of gene arrays for tumor-specific gene discovery is discussed. Study of differential gene expression in glial tumors should help identify the mechanism/s of transformation of normal glial cells to malignant.

Vaccination of malignant glioma patients with peptide-pulsed dendritic cells elicits systemic cytotoxicity and intracranial T-cell infiltration

In this Phase I trial, patients' peripheral blood dendritic cells were pulsed with peptides eluted from the surface of autologous glioma cells. Three biweekly intradermal vaccinations of peptide-pulsed dendritic cells were administered to seven patients with glioblastoma multiforme and two patients with anaplastic astrocytoma. Dendritic cell vaccination elicited systemic cytotoxicity in four of seven tested patients. Robust intratumoral cytotoxic and memory T-cell infiltration was detected in two of four patients who underwent reoperation after vaccination. This Phase I study demonstrated the feasibility, safety, and bioactivity of an autologous peptide-pulsed dendritic cell vaccine for patients with malignant glioma.

Treatment of a patient by vaccination with autologous dendritic cells pulsed with allogeneic major histocompatibility complex class I-matched tumor peptides. Case Report

Dendritic cells (DCs) are antigen-presenting cells that play a central role in the initiation and modulation of antitumor immune responses. In this pilot study, we investigated the ability of autologous DCs pulsed ex vivo with allogeneic major histocompatibility complex class I-matched glioblastoma peptides to stimulate host antitumor immune responses when injected as a vaccine. A patient with recurrent brainstem glioblastoma multiforme (GBM) received a series of three intradermal immunizations of antigen-pulsed DCs on an outpatient basis following surgical debulking of her posterior fossa tumor. Dendritic cell vaccination was well tolerated, and no clinical signs of autoimmunity or experimental allergic encephalomyelitis were detected. She developed a measurable cellular immune response against the allogeneic glioblastoma peptides used in her vaccine preparation, as demonstrated by in vitro T-cell proliferation assays. In addition, increased T-cell infiltration was noted within the intracranial tumor site in the biopsy sample obtained following DC vaccination. An objective clinical response, however, was not evident, and this patient eventually died 21 months after her disease was diagnosed. To our knowledge, this is the first patient with brain cancer ever to be treated with DC-based immunotherapy. This case illustrates that vaccination with DCs pulsed with acid-eluted glioblastoma peptides is feasible and can induce systemic antigen-specific immunity in a patient with recurrent GBM. Additional studies are necessary to determine the optimum DC doses and antigen loading conditions that may translate into clinical effectiveness and survival benefit for patients with brain tumors. Phase I trials for malignant glioma are currently underway.

Glioblastoma induction after radiosurgery for meningioma

A 70-year-old woman developed a glioblastoma in the irradiated field 7 years after stereotactic radiosurgery for meningioma. Glioma induction has been previously reported after external beam radiation for leukaemia, pituitary adenoma, tinea capitus, and meningioma. This radiosurgery-induced malignancy may portend further reports of tumour induction. The theoretical risk of tumour induction by low doses of radiation to normal neural tissue after radiosurgery is now confirmed. Reports of additional cases of radiosurgery-induced tumours might temper the use of this increasingly used technique for benign surgically accessible lesions.

Response of MHC class-1 antigen on rat glioma cells to cytokines

BACKGROUND

Enhanced MHC class-1 expression has potentially been correlated with the increased susceptibility of tumor cells to a T cell-mediated immune response. We examined the immunomodulatory effects of some cytokines on MHC class-1 expression in rat glioma cell lines.

MATERIALS AND METHODS

Using three rat glioma cell lines (RG2, C6, 9L), the immunomodulatory effects of cytokines (rhIL-2, rmIL-4, rmGM-CSF, rrIFN-gamma) on the expression of MHC class-1 antigen were evaluated using immunohistochemical and flow cytometric analyses.

RESULTS

Varying baseline levels of MHC class-1 antigen were confirmed in each glioma cell line. Stimulation with rrIFN-gamma consistently increased the expression of MHC-1 antigen in all three of the rat glioma cell lines. On the other hand, MHC class-1 expression was not affected by stimulation with rhIL-2, rmIL-4 or rmGM-CSF, even in combination.

CONCLUSIONS

rrIFN-gamma can upregulate MHC class-1 expression in rat glioma cells. Our data suggest that rrIFN-gamma may be able to exert antitumor activity against gliomas in vivo.

MRI of thermally denatured blood: methemoglobin formation and relaxation effects

Focal regions of T1-shortening have been observed in magnetic resonance imaging (MRI)-monitored thermal ablations of perfused tissues. The aims of this study were two-fold: to find evidence for heat-induced conversion of hemoglobin (Hb) to methemoglobin (mHb), and to investigate the effects of heat treatment of in-vitro blood components upon their MR relaxation times. Spectrophotometric studies were performed to confirm the heat-induced formation of methemoglobin. Preparations of whole and fractionated blood, previously submitted to elevated temperatures of 40 degrees C to 80 degrees C, were imaged and the relaxation times were calculated. Optical absorption spectra of samples containing free Hb, heated to 60 degrees C, showed increased light absorption at 630 nm, evident of mHb presence. Short T1 values in whole blood (1.13 s) and packed red blood cell (0.65 s) compartments, heated at 60 degrees C, compared to their baseline values (1.62 s and 0.83 s, respectively), were attributed to mHb formation. In relation to MRI-guided thermal interventions, these results suggest a possible explanation for observation of hyperintense regions on T1-weighted images.

Antitumor activity and modified immunoregulation associated with IFN-gamma treatment of RG2 gliomas

BACKGROUND

Interferon-gamma (IFN-gamma) is a key cytokine that upregulates molecules that participate in the processing and presentation of antigen, and effectively induces various immune regulatory factors. IFN-gamma also has cytotoxic or antitumor activities against some tumors in humans as well as animals. In this study, we evaluated the antitumor activity of recombinant rat IFN-gamma (rrIFN-gamma) on RG2 gliomas, and its immunological effect on tumor sites.

MATERIALS AND METHODS

Rats with RG2 gliomas were intracarotidly treated by rrIFN-gamma with or without RMP-7, which has been reported to selectively increase the transport of cytokines to tumor tissue. To evaluate its immunological effect on tumor sites, an immunohistochemical study was performed using monoclonal antibodies against MHC class-1, CD8 and ED2 antigens after rrIFN-gamma treatment.

RESULTS

Intracarotid treatment with high rrIFN-gamma (2.4 x 10(5) U/kg) significantly increased survival (p < 0.02), however, the combined use of RMP-7 and rrIFN-gamma did not result in a further increase. Although the immunohistochemical study showed no clear increase in the staining of MHC class-1 or CD8 antigens on tumors following rrIFN-gamma treatment, immunostaining for ED2 antigen, which is known to be expressed on perivascular cells with MHC class-2 antigen, revealed a clear increase in the number of infiltrating positive cells within the tumors.

CONCLUSION

Intracarotid rrIFN-gamma treatment can increase survival in rat glioma models through a mechanism in which antigen presentation is enhanced, and such effects are not always further increased by combination with RMP-7.

Immunotherapy of malignant brain tumors in children and adults: from theoretical principles to clinical application

In the span of just 10 years, our understanding of the cancer-immune system relationship has increased exponentially, and yet we are only beginning to understand the intricacies of cytokine and immune cell interactions. This paper reviews the interactions of the immune system with brain tumors. In principle, the immune system is uniquely qualified to be an instrument for cancer therapy. An immune response directed against cells bearing tumor antigens could provide a specific and effective mechanism for killing residual tumor. While the theoretical background for immunotherapy as a treatment for brain tumors is elegant and persuasive, a substantial clinical breakthrough has yet to be made. This paper reviews the major forms of both animal and human data on types of immunotherapy, such as passive serological immunotherapy, active, and adoptive immunotherapy. Next a review of existing data on effects of cytokines, immune regulation, and tumor cytotoxicity is detailed. The review concludes with the clinical trials using interferons and other methodologies. The trials presented here demonstrate the challenging work being done to take basic science into the clinical realm. As this work continues, our ability to design effective immune therapies will mature and yield increased therapeutic success.

Treatment of intracranial gliomas with bone marrow-derived dendritic cells pulsed with tumor antigens

OBJECT

An approach toward the treatment of intracranial gliomas was developed in a rat experimental model. The authors investigated the ability of "professional" antigen-presenting cells (dendritic cells) to enhance host antitumor immune responses when injected as a vaccine into tumor-bearing animals.

METHODS

Dendritic cells, the most potent antigen-presenting cells in the body, were isolated from rat bone marrow precursors stimulated in vitro with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4. Cultured cell populations were confirmed to be functional antigen-presenting cells on the basis of expressed major histocompatibility molecules, as analyzed by fluorescence-activated cell sorter cytofluorography. These dendritic cells were then pulsed (cocultured) ex vivo with acid-eluted tumor antigens from 9L glioma cells. Thirty-eight adult female Fischer 344 rats harboring 7-day-old intracranial 9L tumors were treated with three weekly subcutaneous injections of either control media (10 animals), unpulsed dendritic cells (six animals), dendritic cells pulsed with peptides extracted from normal rat astrocytes (10 animals), or 9L tumor antigen-pulsed dendritic cells (12 animals). The animals were followed for survival. At necropsy, the rat brains were removed and examined histologically, and spleens were harvested for cell-mediated cytotoxicity assays. The results indicate that tumor peptide-pulsed dendritic cell therapy led to prolonged survival in rats with established intracranial 9L tumors implanted 7 days prior to the initiation of vaccine therapy in vivo. Immunohistochemical analyses were used to document a significantly increased perilesional and intratumoral infiltration of CD8+ and CD4+ T cells in the groups treated with tumor antigen-pulsed dendritic cells compared with the control groups. In addition, the results of in vitro cytotoxicity assays suggest that vaccination with these peptide-pulsed dendritic cells can induce specific cytotoxic T lymphocytes against 9L tumor cells.

CONCLUSIONS

Based on these results, dendritic antigen-presenting cells pulsed with acid-eluted peptides derived from autologous tumors represent a promising approach to the immunotherapy of established intracranial gliomas. which may serve as a basis for designing clinical trials in patients with brain tumors.

Intra-arterial Cereport (RMP-7) and carboplatin: a dose escalation study for recurrent malignant gliomas

OBJECTIVE

Animal and human studies have shown increased delivery of radiolabeled compounds across the blood-brain-tumor barrier using intra-arterial (IA) Cereport (RMP-7; Alkermes Inc., Cambridge, MA) with a radiolabeled tracer. This present study assesses the safety, tolerance, and preliminary efficacy of the IA administration of carboplatin with Cereport.

METHODS

An open-label dose escalation study of IA Cereport (10-300 ng/kg) with 100 mg of IA carboplatin was conducted in 11 patients with recurrent malignant gliomas and 1 patient treated adjuvantly after radiation therapy. Tumor size and laboratory and clinical statuses were assessed.

RESULTS

Adverse events were mainly neurological in nature and corresponded to the anatomic location of the tumor. Karnofsky performance scale scores did not decline, overall, for those patients who had tumor response. Tumor shrinkage was observed in three of six evaluable patients who received a dose of 300 ng/kg with durable responses of 60, 64, and 106+ weeks.

CONCLUSION

Previous studies have demonstrated increased permeability in human gliomas using IA Cereport. This study demonstrates durable imaging responses using 100 mg of IA carboplatin in combination with Cereport. The drug combination in this patient population seems to be safe and acceptable, providing a novel means of antitumor dose intensification.

Prolonged survival of rats with intracranial C6 gliomas by treatment with TGF-beta antisense gene

Using an intracranial rat C6 glioma model, we tested the hypothesis that gene modification of glioma cells to block the expression of the immunosuppressive cytokine TGF-beta (transforming growth factor beta) may enhance anti-tumor immune responses and thereby prolong survival of tumor-bearing animals. The cDNA for simian TGF-beta 2 was ligated in antisense orientation into the episomal plasmid mammalian expression vector pCEP-4. This TGF-beta-antisense vector was transfected into C6 glioma cells by standard electroporation techniques. PCR was used to determine that the rat C6 clones were successfully transfected with the antisense-TGF beta construct. Twenty-nine adult female Wistar rats harboring 7-day-old intracranial C6 tumors were then subcutaneously injected with either saline (n = 9), unmodified C6 glioma cells (n = 10), or TGF-beta-antisense-modified C6 cells (n = 10). Animals were followed for survival, and Fisher's exact method was used to interpret the significance of difference between experimental groups. The survival of tumor-bearing rats injected with TGF-beta-antisense-modified C6 cells was significantly prolonged, relative to the survival of rats receiving injections of saline or unmodified C6 cells alone. Six of the ten (60%) TGF-beta-antisense treated animals survived for 12 weeks, whereas none of the nine (0%) animals treated with saline and none of ten (0%) of those treated with C6 cells alone survived past 5 weeks. These results indicate that the genetic inhibition of immunosuppressive cytokines (such as TGF-beta) may reverse the phenotypic immunosuppression caused by such factors, and thereby prolong the survival of C6 tumor-bearing animals. Future investigations using cytokine gene modifications in other brain tumor models are warranted.

Novel human malignancy-associated gene (MAG) expressed in various tumors and in some tumor preexisting conditions

We have identified a novel human malignancy-associated gene (MAG) expressed in various malignant tumors including glioblastomas and hepatocellular carcinomas (HCCs) and in tumor preexisting conditions such as hepatitis C virus- and hepatitis B virus-induced liver cirrhosis. The expression of MAG was characterized using reverse transcription-PCR (RT-PCR), rapid amplification of cDNA ends PCR, RNA dot blotting, RNase protection assay, and Northern blot analysis. Rapid amplification of cDNA ends PCR yielded a 536-bp MAG fragment in HCC, macroregenerative liver nodules with dysplasia, and liver cirrhosis but not in normal liver or placenta. By RT-PCR, MAG expression was not found in 12 different normal tissues but found in 46 of 51 (90%) premalignant and malignant tissues of various sites. Embryonic liver and brain were positive for MAG expression together with tumors from the same organs, but the corresponding normal adult tissues were negative. By RNase protection assay, MAG mRNA was expressed in the HepG2 liver tumor cell line and in an ovarian carcinoma but not in normal liver. The estimated transcript size from Northern blot analysis was 8.8 kb. This novel gene may play a role in the progression of premalignant conditions and in the development of HCC and other cancers.

Nitric oxide and cyclic GMP attenuate sensitivity of the blood-tumor barrier permeability to bradykinin

Intracarotid infusion of bradykinin and its analogue, RMP-7, selectively increase the permeability of brain tumor capillaries though the nitrix oxide (NO) and cyclic GMP pathway. Maximum blood-tumor barrier (BTB) permeability induced by bradykinin is observed at 15 min after intracarotid infusion and this effect is decreased even if the infusion continues. The mechanism for this decreased effect with long term infusion has not been clearly defined. This study sought to determine the involvement of the NO-cyclic GMP pathway in this event. Regional permeability was investigated in 44 Wistar rats with implanted RG2 gliomas, using quantitative autoradiography to determine the unidirectional transfer constant (Ki) of radiolabeled 14C-dextran. Tumor bearing rats were treated by intracarotid infusion of bradykinin (10 micrograms kg-1 min-1) with or without pretreatment with bradykinin, the NO donor s-nitrosoglutathione (10 nmol kg-1 min-1), or the cyclic GMP analogue, 8Br-cyclic GMP (200 micrograms kg-1 min-1). At 30 min of bradykinin infusion, BTB permeability was significantly lower compared to 15 min of bradykinin infusion (3.79 +/- 0.99 vs. 16.20 +/- 3.43 microliters g-1 min-1, p < 0.001). Pretreatment with an NO donor significantly decreased BTB permeability in bradykinin infused rats (5.09 +/- 2.61 vs. 13.51 +/- 4.19 microliters g-1 min-1, p < 0.001), as did pretreatment with a cyclic GMP analogue (4.48 +/- 0.95 vs. 12.31 +/- 3.90 microliters g-1 min-1, p < 0.001). There was no increased permeability in nontumor brain areas. Increased tumor permeability by bradykinin appears to be regulated by NO and cyclic GMP which are second messengers involved in the bradykinin B2 receptor mediated cascade.

Topographical and temporal specificity of human intraoperative optical intrinsic signals

The goal of this study was to determine the topographical and temporal specificity of neuronal and vascular responses using an intraoperative optical technique (iOIS). The face, thumb, index, and middle fingers were stimulated individually to obtain separate maps of cortical activation. Peak optical responses provided unique, non-overlapping cortical brain maps. Non-peak signals were more dispersed and produced overlapping responses from different digits. Peak iOIS responses colocalized with electrocortical stimulation mapping and evoked potentials. Temporally, we observed statistically significant specificity corresponding to sequential cortical activation during early optical signals (500-1750 ms), but later perfusion responses were non-specific. To our knowledge, this is the first report of either topographical specificity in overlapping spatial patterns, and/or temporal specificity in early perfusion profiles. These results therefore may have significant implications for other perfusion dependent functional imaging techniques.

Intracarotid low dose bradykinin infusion selectively increases tumor permeability through activation of bradykinin B2 receptors in malignant gliomas

Intracarotid low dose bradykinin infusion can selectively increase permeability in brain tumor capillaries. However, the mechanism by which bradykinin selectively increases transport into brain tumors and not normal brain has not been clearly defined. This study therefore sought to determine whether the mechanism by which bradykinin increases tumor permeability specifically involves the bradykinin B2 receptor in brain tumor tissue. In permeability studies, 27 Wistar rats with RG2 gliomas were utilized and a unidirectional transport, Ki, of radiolabeled [14C] sucrose was determined using quantitative autoradiography. Bradykinin (10 microg kg-1 min-1) increased the transport of sucrose to tumors 2.1-fold compared to saline infusion alone (p<0.001). The uptake of sucrose in tumors was significantly inhibited by the bradykinin B2 receptor antagonist, d-Arg, [Hyp3, Thi5,8, d-Phe7]-bradykinin (p<0.01), but not by the B1 receptor antagonist, des-Arg9, [Leu8]-bradykinin. The distribution of B2 receptors in normal brain and tumor tissue was examined by immunohistochemistry using the B2 receptor antiserum, AS 424. High levels of B2 receptors were detected in intracerebral RG2 glioma and brain surrounding tumor (BST), but not in normal brain tissue. These results indicate that the permeabilizing effects of bradykinin are mediated through bradykinin B2 receptors, and that differences in distribution of B2 receptors between tumor tissue and normal brain may be responsible for the selective effects on tumor tissue.

Adenovirus-mediated p53 gene delivery potentiates the radiation-induced growth inhibition of experimental brain tumors

Patients with malignant gliomas continue to have very poor prognosis even after surgical resection, radiation and chemotherapy. Because these tumors often have alterations in the p53 tumor suppressor gene, which plays a key role in the cellular response to DNA damaging agents, we investigated the role of p53 gene therapy in conjunction with ionizing radiation in a rat brain tumor model. Exposure of cultured rat 9L gliosarcoma cells, which contain a mutant p53 gene, to a recombinant adenovirus-vector bearing the wild-type p53 gene (Adp53), induced apoptosis within 24 hours. Although ionizing radiation had no additional effect on apoptosis within this time frame, it caused G1 arrest in non-apoptotic cells after Adp53 therapy. In contrast, wild-type 9L cells demonstrated little G1 arrest after X-irradiation. When animals bearing brain tumors were irradiated after intratumoral Adp53 injections, more than 85% reduction in tumor size was noted. Moreover, the group of rats receiving both radiation and Adp53 therapy had a significant increase in survival as compared to animals receiving either therapy alone. These results support the use of p53 gene therapy as an adjunct to radiation in treatment of malignant brain tumors.

Cyclic GMP-specific phosphodiesterase inhibition and intracarotid bradykinin infusion enhances permeability into brain tumors

Intracarotid infusion of bradykinin selectively increases the delivery of compounds into brain tumors. This study sought to determine the role of cyclic GMP in increased permeability across the blood-tumor barrier (BTB) after infusion of bradykinin. In permeability studies, 186 Wistar rats with RG2 gliomas and C6 gliomas were used. Transport across the BTB was quantified by autoradiography and reported as a unidirectional transport, Ki, for [14C]dextran (Mr 70,000) and [14C]aminoisobutyric acid (Mr 103,000), with or without inhibition of cyclic GMP-specific phosphodiesterase or soluble guanylate cyclase. We also determined cyclic GMP levels in tumors and normal brain, with or without intracarotid bradykinin infusion, using RIA. Intracarotid infusion of bradykinin selectively increased permeability in RG2 tumors and C6 tumors for both tracers. Simultaneous infusion of bradykinin and a cyclic GMP-specific phosphodiesterase inhibitor, zaprinast (20 mg/kg), resulted in significantly increased permeability across the BTB, compared to intracarotid bradykinin infusion alone. Zaprinast also significantly prolonged the permeability effects of bradykinin. Pretreatment using i.v. infusion of the soluble guanylate cyclase inhibitor, LY-83583 (125 microg/kg), significantly attenuated the bradykinin effect of opening the BTB. Cyclic GMP levels in RG2 and C6 tumors were significantly increased after intracarotid bradykinin infusion (2.8- and 2.2-fold, respectively). Cyclic GMP levels in normal brain were not increased by bradykinin infusion. These results show that increasing cyclic GMP in tumor microvessels can increase permeability in response to bradykinin.

Steroids decrease uptake of carboplatin in rat gliomas--uptake improved by intracarotid infusion of bradykinin analog, RMP-7

This study sought to determine whether dexamethasone (DXN) treatment of rats with intracranial gliomas would 1) further impair delivery of carboplatin to brain tumors, and 2) whether intracarotid infusion of the bradykinin analog, RMP-7, would improve delivery during concurrent DXN treatment. In DXN pretreated animals, 3 mg/kg/day of DXN was administered intraperitoneally for 3 days prior to Ki determinations. Ki of [14C] carboplatin into DXN-treated tumors and brain surrounding tumor (BST) was significantly lower compared to non-DXN treated tumors and BST (3.30 +/- 0.91 vs. 4.47 +/- 1.80, p < 0.05, and 0.94 +/- 0.84 vs. 2.18 +/- 0.79, p < 0.05, respectively). Intracarotid infusion of RMP-7 significantly increased the Ki for carboplatin in DXN-treated tumors (6.35 +/- 3.10 vs. 3.30 +/- 0.91, p < 0.01), however, RMP-7 increased Ki to a greater extent in tumors not pretreated with DXN (12.07 +/- 3.60 vs. 4.47 +/- 1.80, p < 0.0001). Dexamethasone decreases transport of carboplatin into brain tumors. Intracarotid infusion of RMP-7 selectively increases carboplatin transport to tumors.

Do calendars enhance posttraumatic temporal orientation?: a pilot study

The purpose of this study was to determine the effectiveness of an in-room calendar to correct temporal disorientation in a brain-injured population. Thirty consecutive brain injured patients (16 traumatic, 14 non-traumatic) admitted to a brain injury rehabilitation unit were randomly assigned to either a group with in-room calendars (n = 14) or a group without calendars (n = 16). A baseline Temporal Orientation Test (TOT) score was obtained. Daily TOT scores were obtained for patients throughout their rehabilitation stay or until two consecutive normal scores were obtained. When orientation errors were made, they were corrected and the attention of the patient was drawn to the calendar. There were no statistically significant associations between group and age, gender or mean GCS (for patients with traumatic etiology). Only baseline length of post-traumatic amnesia (PTA) had a significant association with eventual emergence from PTA (as defined by a normal score on the TOT). Age and presence of calendar were not significant. In-room calendars have been espoused as orientation aides. The data from this pilot study suggest that calendars do not hasten re-orientation. This finding suggests that other widely held but not rigorously tested beliefs regarding cognitive rehabilitation may need to be examined.

Intra-arterial administration of carboplatin and the blood brain barrier permeabilizing agent, RMP-7: a toxicologic evaluation in swine

RMP-7 is a bradykinin B2 receptor agonist shown to permeabilize the blood-brain barrier, especially that associated with brain tumors, when administered via both intracarotid and intravenous routes. Both routes of administration are currently being tested in human trials in combination with the chemotherapeutic agent carboplatin as therapy for gliomas. As an essential prerequisite to the initial intracarotid clinical trials, the potential neurotoxicity of intra-arterial administration of RMP-7 (at a high or low dose), alone and in combination with carboplatin, was assessed in anesthetized Red Duroc swine. Five treatment groups were evaluated with each pig receiving a series of alternating, intra-arterial infusions of RMP-7 (or saline) followed by carboplatin (or saline), as follows: (1) vehicle control: saline/saline; (2) carboplatin only control: saline/carboplatin (50 mg total); (3) RMP-7 only control: RMP-7 (750 ng/kg)/saline; (4) low dose combination: RMP-7 (75 ng/kg)/carboplatin (50 mg total); and (5) high dose combination: RMP-7 (750 ng/kg)/carboplatin (50 mg total). For each subject, one of the alternating dosing sequences (above) was repeated four times during a single dosing session which lasted approximately 40 minutes. Assessments during the in-life phase of the study in the pre- and post-treatment periods consisted of heart rate, arterial blood pressure (systolic, diastolic, and mean), blood gases, body weight, general clinical observations (including evaluation for neurological deficit) and clinical pathology (including a comprehensive battery of standard blood coagulation, hematological and serum chemistry tests). In addition, during the time of treatment, heart rate and arterial blood pressure were monitored. The animals were terminated two weeks after dosing and the brain and rete mirabile (distal to site of infusion) were evaluated for gross and histopathological abnormalities. The histopathology analysis included a reader-blinded analysis using low and high power light microscopic examination of both H&E and Kluver-Berrera stained sections through several key cortical and subcortical brain regions. Transient decreases in arterial blood pressure (mean of 10-25 mmHg) were observed in both groups receiving the high dose of RMP-7 (i.e., 750 ng/kg). No other side effects attributable to RMP-7 and/or carboplatin were observed, and clinical observations revealed no evidence of neurologic deficits. Post-mortem examination revealed no evidence of CNS or cerebral vascular pathology attributable to carboplatin and RMP-7. This study demonstrates that intracarotid administration of the maximum tolerated dose of RMP-7 (750 ng/kg) alone, or in combination with carboplatin (50 mg) is not accompanied by any serious adverse effect, apparent cerebrovascular abnormality or neuropathologic consequence and offers further evidence for the safety of this novel therapeutic approach for enhancing delivery of chemotherapeutics to brain tumors.

Intra-arterial carboplatin chemotherapy for brain tumors: a dose escalation study based on cerebral blood flow

PURPOSE

To perform in intra-arterial dose escalation study of carboplatin based on hemispheric blood-flow estimation in patients with recurrent malignant glioma. The primary purpose was to determine the maximally tolerated intra-arterial dose.

METHODS AND PATIENTS

Methods included: 1) selective intra-arterial delivery performed with modern microcatheters, 2) pulsatile infusion, and 3) dosage based on local cerebral blood-flow estimation (middle cerebral artery 60%, anterior cerebral artery 20%, posterior cerebral artery 15%, and anterior choroidal artery 5% of the hemispheric blood-flow). The deliveries were performed above the ophthalmic artery in the anterior circulation, or above the anterior inferior cerebellar arteries in the posterior circulation. The doses were escalated from 200 mg/hemisphere at 50 mg increments. Twenty-one patients were studied (14 with glioblastoma multiforme, five anaplastic astrocytoma, one aggressive low-grade glioma, one metastasis). Patients had recurrent glioma limited to one hemisphere and Karnofsky score of 50 or greater. Concomitant therapies were allowed.

RESULTS

Carboplatin was escalated to a dose of 1400 mg/hemisphere. One patient had a permanent neuromotor decline. The predominant toxicity was hematopoietic. The median time to tumor progression was 22 weeks, median survival 39 weeks, and the response rate 70% (50% SD and 20% PR) of 19 patients.

CONCLUSIONS

Hemispheric blood-flow estimation allowed us to escalate the dose of intra-arterial carboplatin to twice what was previously considered safe. Responses compared favorably to previous studies. Further studies are needed to determine if this method will provide improved and durable responses.

Prolonged treatment with biologic agents for malignant glioma: a case study with high dose tamoxifen

Traditional study design for treatment of malignant gliomas does not allow tumor progression to be greater than 25-50 percent without terminating treatment. This design may prevent recognition of patients who benefit from the treatment either by slowed growth or delayed response. A delayed response or slowed growth may be characteristic of biologic agents being evaluated in the treatment of malignant glioma. Because of the low toxicity of certain biologic drugs, continued treatment through tumor growth can be ethically considered in study design. The effect of biologic agents on a neoplasm may include cellular differentiation, retardation of growth, cytostasis, cytocidal effects, or apoptosis. Such effects may clinically translate into a complete response, partial response, stable disease or retardation of growth with or without an eventual reduction of tumor. We present a patient with a recurrent malignant glioma who was continued on high dose tamoxifen despite radiologic documented doubling of the tumor size and who eventually showed a delayed response to this agent nine months after initiation of treatment. Strong consideration should be given to the prolonged treatment of non-toxic biologic agents in a controlled clinical trial, where agents have shown some benefit in phase one studies.

Posttraumatic amnesia: its relation to functional outcome

OBJECTIVE

To investigate the relation between duration of posttraumatic amnesia (PTA) and functional outcome in a traumatically brain injured population.

PATIENTS

Two hundred seventy-six patients with traumatic brain injury (TBI) who were admitted to a Level I university trauma center and required inpatient rehabilitation.

MEASURES

Duration of PTA was assessed by serial administrations of the Galveston Orientation Amnesia Test (GOAT). Functional Independence Measure (FIM) total scores, FIM cognitive and motor subscores, and Disability Rating Scale (DRS) scores were obtained at admission and discharge from inpatient rehabilitation.

RESULTS

Duration of PTA was a significant predictor of all admission and discharge DRS and FIM scores. Duration of PTA and age at the time of injury, in combination, contributed significantly to the prediction of the DRS score and FIM total, cognitive, and motor scores at discharge.

CONCLUSION

Duration of PTA appears to be a useful variable in predicting specific functional outcome in the TBI population receiving inpatient rehabilitation services. The use of age as a factor in addition to duration of PTA enhances the prediction of functional outcome.

Enhanced cytokines delivery and intercellular adhesion molecule 1 (ICAM-1) expression in glioma by intracarotid infusion of bradykinin analog, RMP-7

The effect of intracarotid infusion of the bradykinin analog, RMP-7, on blood-to-tumor and blood-to-brain transport of three cytokines were investigated. Wistar rats with RG2 gliomas were utilized and a unidirectional transfer constant, Ki, was determined using quantitative autoradiography. Interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and interleukin-2 (IL-2) were labeled with 125Iodine for quantitative transport studies using autoradiography. Radiolabeled cytokines were injected as an intravenous bolus. Intracarotid infusion of RMP-7 (0.1 microgram kg-1 min-1) increased the selective transport to tumors of IFN-gamma by 3.97-fold (p < 0.005), of TNF-alpha by 5.30-fold (p < 0.005), and of IL-2 by 4.34-fold (p < 0.005), compared to intracarotid saline infusion. To determine whether the increased IFN-gamma or TNF-alpha transport to tumors with RMP-7 could enhance expression of intercellular adhesion molecule 1 (ICAM-1) in tumors, ICAM-1 expression in RG2 glioma was evaluated by immunohistochemistry. Both IFN-gamma and TNF-alpha increased ICAM-1 expression of RG2 cells in vitro. In vivo, intracarotid infusion of IFN-gamma combined with RMP-7 significantly enhanced ICAM-1 expression in intracerebral RG2 gliomas compared to infusion of IFN-gamma without RMP-7. Expression of ICAM-1 was not enhanced by TNF-alpha combined with RMP-7. Intracarotid infusion of RMP-7 is a novel method of cytokines delivery to brain tumors.

Steroids decrease uptake of carboplatin in rat gliomas--uptake improved by intracarotid infusion of bradykinin analog, RMP-7

A blood-tumor barrier (BTB) limits delivery of antitumor agents to brain tumors. This study sought to determine whether dexamethasone (DXN) treatment of rats with intracranial gliomas would 1) further impair delivery of carboplatin to brain tumors, and 2) whether intracarotid infusion of the bradykinin analog, RMP-7, would improve delivery during concurrent DXN treatment. Wistar rats with RG2 gliomas were utilized and a unidirectional transport, Ki, of radiolabeled [14C] carboplatin was determined using quantitative autoradiography. In DXN pretreatment animals, 3 mg/kg/day of DXN was administered intraperitoneally for 3 days prior to Ki determinations. At 10 days after tumor implantation, Ki of [14C] carboplatin into DXN-treated tumors and brain surrounding tumor (BST) was significantly lower compared to non-DXN treated tumors and BST (3.30 +/- 0.91 vs. 4.47 +/- 1.80, p < 0.05, and 0.94 +/- 0.84 vs. 2.18 +/- 0.79, p < 0.05, respectively). Intracarotid infusion of RMP-7 (0.1 mg/kg/min) significantly increased the Ki for carboplatin in DXN-treated tumors (6.35 +/- 3.10 vs. 3.30 +/- 0.91, p < 0.01), however, RMP-7 increased Ki to a greater extent in tumors not pretreated with DXN (12.07 +/- 3.60 vs. 4.47 +/- 1.80, p < 0.0001). Our studies show that dexamethasone decreases transport of carboplatin into brain tumors. Intracarotid infusion of RMP-7 selectively increases carboplatin transport to tumors.

Functional outcome after violence related traumatic brain injury

Violent injuries have become an increasingly prevalent cause of traumatic brain injury (TBI). These injuries can be classified as either penetrating or non-penetrating in nature. While much of the research on violence has been within a military population, there exists a marked difference between military and civilian injuries. Prior work has reported relatively poor outcomes for those individuals who have suffered penetrating TBIs, but little has been done to assess specific functional outcome parameters in survivors. We examined 25 subjects that had sustained blunt injuries and 25 cases with penetrating injuries as a result of a violent act. Cases were matched by initial Glasgow Coma Scale (GCS), age and educational level. Mean GCS for this study sample was 8.8. The following outcome variables were assessed at rehabilitation admission and discharge and at 1 year post injury: Disability Rating Scale (DRS), Rancho Los Amigos Scale (LCFS), Functional Independence Measure (FIM) (ambulation, expression items), length of stay, and cost of care. Student's t-tests were performed to assess for differences between the two groups. No significant differences were noted between the groups for any of the outcome variables. Although penetrating injuries may have a higher initial mortality, those who survive to come to rehabilitation appear to have similar outcomes to those patients with non-penetrating violence related injuries.

Intracarotid infusion of RMP-7, a bradykinin analog, and transport of gallium-68 ethylenediamine tetraacetic acid into human gliomas

The bradykinin analog, RMP-7, was investigated for its ability to increase selectively the transport of 68Ga ethylenediamine tetraacetic acid (EDTA) into recurrent malignant gliomas in nine patients. For each patient, two position emission tomography (PET) studies (one with and one without RMP-7) were performed. For studies with RMP-7, 10 to 300 ng/kg of the compound was infused into the supraophthalmic carotid artery over 15 minutes. In each PET study, a sequence of PET scans was initiated simultaneously with an intravenous bolus of 68Ga EDTA (5-10 mCi). Arterial samples were taken to provide the input function. All PET scans were coregistered to the magnetic resonance (MR) images of the patient. Regions of interest were defined for tumor and normal tissue regions on MR images and were copied to the coregistered PET dynamic images to provide brain tissue-time activity curves. The constant (Ki) for the transport of gallium-68 from plasma to brain tissue was determined using a simple compartmental model. Intracarotid infusion of RMP-7 significantly increased transport into tumor regions with an average increase of 46 +/- 42% (mean +/- standard deviation, p < 0.05). Permeability in normal tissue regions was not significantly increased. Tumors in three of six patients treated with 300 ng/kg RMP-7 and carboplatin had at least a 50% reduction in tumor volume as measured by MR imaging. Intracarotid infusion of RMP-7 is a novel technique for selective delivery of antitumor compounds into brain tumors.

A multimedia database system for thermal ablation therapy of brain tumors

A prototype multimedia medical database is described for supporting thermal ablation therapy of brain tumors. Its design is motivated by the major need to manage and access multimedia information on the progress and reaction of tumors to various therapy protocols. The database links images to patient data in a way that permits the use to view and query medical information using alphanumeric, temporal, and feature-based predicates. Visualization programs permit the user to view or annotate the query results in various ways. These results support the wide variety of data types and presentation methods required by neuroradiologists to manage thermal ablation therapy data. The database satisfactorily meets the requirements defined by thermal ablation therapy. A similar approach is being undertaken for supporting different therapies of other types of tumors, thus showing the generality of our approach.

Revised trauma score: an additive predictor of disability following traumatic brain injury?

Recent studies have clarified the role of hypoxic-ischemic damage as a secondary factor in traumatic brain injury (TBI). Many trauma centers are now consistently using the Revised Trauma Score (Glasgow Coma Scale, systolic blood pressure, and respiratory rate) to assist with triage of multitrauma patients. This study investigated the predictive power of the Revised Trauma Score (RTS) instead of the Glasgow Coma Scale (GCS) in determination of disability as measured by the Disability Rating Scale (DRS). Data were obtained as part of the National Institute for Disability and Rehabilitation Research TBI Model Systems database on 501 patients receiving acute medical care and inpatient rehabilitation within a coordinated neurotrauma program for treatment of TBI. Initial RTS and GCS were obtained on admission to the emergency department, along with the lowest GCS measured in the first 24 h. Analysis of initial RTS and GCS demonstrated modest, but statistically significant Pearson's correlations with DRS at rehabilitation admission (-0.18 and -0.25, respectively) and discharge (-0.22 and -0.24, respectively). Lowest GCS within the first 24 h postinjury also failed to show a strong relationship with DRS at rehabilitation admission (-0.28) and discharge (-0.24). Multiple regression analysis performed on RTS subsets for systolic blood pressure and respiratory rate did not reveal an added predictive value. Although RTS may be important in emergency triage for its ability to predict mortality, this study indicates its limited usefulness in prediction of disability.

Unlocking the blood-brain barrier: a role for RMP-7 in brain tumor therapy

The effect and mechanism of the blood-brain barrier-permeabilizing agent, RMP-7, was investigated in a series of studies employing a rat RG2 glioma model. Changes in uptake of carboplatin into brain tumor and various nontumor brain tissue regions was determined using a sophisticated image analysis system. This system permitted quantitative autoradiography to be analyzed simultaneously with overlayed histological images from the same coronal brain section. A wide range of intracarotid doses of RMP-7 (0.01 to 9.0 micrograms/kg) was shown to significantly increase the permeability of carboplatin into tumor tissue and surrounding brain tissue (up to twofold) in a dose-dependent manner. Additionally, substantially greater permeability effects were seen in the tumor compared to healthy brain. Moreover, a clear topographic profile was observed in nontumor brain tissue, with progressively less uptake observed with increasing distance from the tumor. The fact that RMP-7 increased the uptake of carboplatin into ipsilateral brain tissue outside the tumor mass has potential implications for treating human glioma patients, for it is commonly recognized that tumor cells typically migrate from the tumor mass into surrounding brain tissue thereby escaping conventional attempts to destroy the malignant cells. To help elucidate the mechanism of RMP-7's permeability effects, the uptake of carboplatin was also determined under conditions where either the bradykinin B2 receptor antagonist, HOE140, or the B1 antagonist, [desArg10]HOE140, was coadministered with RMP-7. Results indicate that RMP-7's effects are mediated specifically through bradykinin B2 receptors. Furthermore, neither bradykinin antagonist alone affected the uptake of carboplatin into the leaky tumor region, suggesting that abnormal elevations in endogenous bradykinin activity are not likely responsible for the characteristic leaky nature of the tumor vascular barrier. The combined results from these studies therefore offer new insight into the characteristics of the vascular barriers in normal and tumor brain tissue and further elucidate the novel permeability effects of RMP-7. Together, they support its potential use as an adjunctive therapy for the selective delivery of chemotherapeutic drugs to brain tumors and possibly other neurodegenerative conditions.

Relationship between Glasgow coma scale and functional outcome

The Glasgow Coma Scale (GCS) is routinely used in the acute care setting after traumatic brain injury (TBI) to guide decisions in triage, based on its ability to predict morbidity and mortality. Although the GCS has been previously demonstrated to predict mortality, efficacy in prediction of functional outcome has not been established. The purpose of this study was to assess the value of the acute GCS in predicting functional outcome in survivors of TBI. This study used the Multicenter National Institute on Disability and Rehabilitation Research TBI Model Systems database of 501 patients who had received acute medical care and inpatient rehabilitation within a coordinated neurotrauma program for treatment of TBI. Initial and lowest 24 hr GCS scores were correlated with the following outcome measures: the Disability Rating Scale (DRS), Rancho Los Amigos Levels of Cognitive Functioning Scale (LCFS), and cognitive and motor components of the Functional Independence Measure (FIM(SM)-COG and FIM(SM)-M). Outcome data were collected at admission to and discharge from the inpatient TBI rehabilitation unit. Correlation analysis revealed only modest, but statistically significant, relationships between initial and lowest GCS scores and outcome variables. Initial and lowest GCS score comparison with outcome demonstrated the following correlation coefficients: admission DRS, -0.25 and -0.28; discharge DRS, -0.24 and -0.24; admission LCFS, 0.31 and 0.33; discharge LCFS, 0.27 and 0.25; admission FIM-COG, 0.36 and 0.37; discharge FIM-COG, 0.23 and 0.23; admission FIM-M, 0.31 and 0.31; discharge FIM-M, 0.25 and 0.21. The GCS as a single variable may have limited value as a predictor of functional outcome.