The potential for genetically altered microglia to influence glioma treatment

Diffuse and unstoppable infiltration of brain and spinal cord tissue by neoplastic glial cells is the single most important therapeutic problem posed by the common glioma group of tumors: astrocytoma, oligoastrocytoma, oligodendroglioma, their malignant variants and glioblastoma. These neoplasms account for more than two thirds of all malignant central nervous system tumors. However, most glioma research focuses on an examination of the tumor cells rather than on host-specific, tumor micro-environmental cells and factors. This can explain why existing diffuse glioma therapies fail and why these tumors have remained incurable. Thus, there is a great need for innovation. We describe a novel strategy for the development of a more effective treatment of diffuse glioma. Our approach centers on gaining control over the behavior of the microglia, the defense cells of the CNS, which are manipulated by malignant glioma and support its growth. Armoring microglia against the influences from glioma is one of our research goals. We further discuss how microglia precursors may be genetically enhanced to track down infiltrating glioma cells.

Permanent, lowered HLA class I expression using lentivirus vectors with shRNA constructs: Averting cytotoxicity by alloreactive T lymphocytes

Transplantation of many tissues requires histocompatibility matching of human leukocyte antigens (HLA) to prevent graft rejection, to reduce the level of immunosuppression needed to maintain graft survival, and to minimize the risk of graft-versus-host disease, particularly in the case of bone marrow transplantation. However, recent advances in fields of gene delivery and genetic regulation technologies have opened the possibility of engineering grafts that display reduced levels of HLA expression. Suppression of HLA expression could help to overcome the limitations imposed by extensive HLA polymorphisms that restrict the availability of suitable donors, necessitate the maintenance of large donor registries, and complicate the logistics of procuring and delivering matched tissues and organs to the recipient. Accordingly, we investigated whether knockdown of HLA by RNA interference (RNAi), a ubiquitous regulatory system that can efficiently and selectively inhibit the expression of specific gene products, would enable allogeneic cells to evade immune recognition. For efficient and stable delivery of short hairpin-type RNAi constructs (shRNA), we employed lentivirus-based gene transfer vectors, which provide a delivery system that can achieve integration into genomic DNA, thereby permanently modifying transduced graft cells. Our results show that lentivirus-mediated delivery of shRNA targeting pan-Class I and allele-specific HLA can achieve efficient and dose-dependent reduction in surface expression of HLA in human cells, associated with enhanced resistance to alloreactive T lymphocyte-mediated cytotoxicity, while avoiding MHC-non-restricted killing. We hypothesize that RNAi-induced silencing of HLA expression has the potential to create histocompatibility-enhanced, and, eventually, perhaps "universally" compatible cellular grafts.

Suicide gene therapy with Herpes simplex virus thymidine kinase and ganciclovir is enhanced with connexins to improve gap junctions and bystander effects

Connexins are proteins that form gap junctions between cells in various mammalian tissues. Because of their role in intercellular communication, connexins are important in the bystander cell death seen in Herpes simplex virus-thymidine kinase (HSV-TK) gene therapy for brain tumors. A selective review of connexin transduction/transfection studies with particular emphasis to central nervous system tumor cells is presented. In addition, specific references to studies with cell types that demonstrate low gap junction intercellular communication are presented. Data are included with the HT-29 colorectal tumor cell line to support the concept that enhancing gap junction protein expression in otherwise low gap junction communicating HT-29 cells increases bystander cell death and reduces tumor burden beyond what might be expected from HSV-TK and ganciclovir (GCV) treatment alone. Maximum in vitro bystander cell death was always produced when GCV treated co-cultures of TK-transduced and non-TK-transduced HT-29 cell lines were also transduced with connexin-43. When connexin was present in only one group of cells in the co-culture, there was more bystander cell death observed with connexin transduced into the non-TK-transduced cells, rather than the TK-transduced cells. The data presented reinforces conclusions made from earlier findings from cell line mixing experiments in which the non-TK-transduced cell population determined the level of bystander cell death (Burrows et al., 2002).

Strategies using the immune system for therapy of brain tumors

Phase II immunotherapy and gene therapy studies should be pursued because of encouraging results in many phase I studies. Future testing in this field may consider modifications of some of the above-mentioned combined strategies. For instance, in the immunization and adoptive transfer studies performed by Holladay et al and by Plautz et al, the systemic adoptive transfer could be altered to intratumoral placements of effector cells. This permutation may be more efficacious because local adoptive immunotherapy approaches involve placement of effector cells where they are needed. Additionally, new avenues of gene therapy are being explored that may offer added beneficial effects for immunization, local or systemic adoptive immunotherapy, or combined chemotherapy and adoptive immunotherapy of tumors. With new genetic tools, such as microarray analyses, SEREX, and creation of cDNA libraries from tumor cells, significant progress in the treatment of neoplasms in the immunologically privileged brain should be forthcoming.

Chemo-immunotherapy and chemo-adoptive immunotherapy of cancer

The chemo-immunotherapy (CIT) and chemo-adoptive immunotherapy (CAIT) regimens tested in the past decade are summarized. From them we have learned a great deal about the interactions between various chemotherapeutic agents, immune modulating agents and effector cells. The most commonly reported result in multi-modality experiments with CAIT has been a synergistic enhancement in antitumor activity. Clinical trials usually demonstrated improvement in patient quality of life, an extension of survival time, and occasional complete regression of tumor. In many animal models, this enhancement often meant the complete regression and apparent cure of tumor in the animal. One mechanism by which this synergistic enhancement takes place appears to be a suppression of tumor-associated suppressor T cell activity by the chemotherapeutic agents, thereby inducing enhanced cytolytic activity against tumor by the adoptively transferred, activated effector cells. In CAIT the most commonly used drug has been cyclophosphamide. In CIT a wide variety of chemotherapy agents have been used but none of the clinical trials made use of cyclophosphamide. Thus, direct comparisons are not possible. Suggestive of the intricate regulatory processes involved, many CIT studies indicate a synergy only when specific doses of chemotherapy and immunotherapy agents are given, and in a specific sequence. CIT has become less toxic, is being handled on a cost-effective outpatient basis, while maintaining similar objective response rates to earlier inpatient treatments. In the future, CAIT and CIT will probably have an increasing role in the management of patients with specific cancers.

Immunologic approaches to therapy for brain tumors

Malignant brain tumors are notoriously invasive. Although surgical debulking can relieve the patient of the main mass of tumor, adjuvant treatments are needed to target the glioma cells that infiltrate through normal parenchyma as single cells or pockets of tumor cells from which recurrent tumors arise. Successful adjuvant cellular therapy of brain tumors, or activation of endogenous immune cells, requires that either cell effectors make direct contact with tumor cells or come within close proximity to them and exert an indirect effect. This review examines current clinical trials aimed at direct lysis of glioma cells and trials making gliomas more visible to the endogenous immune system.

The human leukemic T-cell line, TALL-104, is cytotoxic to human malignant brain tumors and traffics through brain tissue: implications for local adoptive immunotherapy

Preclinical studies with the human MHC nonrestricted cytotoxic T-cell leukemic line, TALL-104, were performed in anticipation of its use in cellular immunotherapy trials for primary malignant brain tumors. In this study, we have: (a) quantitated the in vitro brain tumor cell lysis; (b) measured the cytokine secretion upon coincubation of TALL-104 cells with brain tumor cells; (c) investigated the effect of dexamethasone on brain tumor cell cytolysis by TALL-104 cells; (d) explored the effects of lethal irradiation and cryopreservation on TALL-104 cell viability and lytic efficacy; and (e) estimated the damage TALL-104 cells induce to murine normal and tumor brain cells and their trafficking patterns in both normal and tumor-bearing rat brain upon intracranial infusion. In vitro coincubation of TALL-104 cells with human brain tumor cells, explants, and cell lines resulted in significant lysis of them, but normal brain cells were spared. Lysis of tumor at 4 h was unaffected by dexamethasone or lethal irradiation. Secretion of tumor necrosis factor-alpha, tumor necrosis factor-beta, IFN-gamma, or granulocyte/macrophage-colony stimulating factor upon TALL-104 cell coincubation with brain tumor cells variably occurred without always correlating with lysis. In vivo experiments using irradiated TALL-104 cells, placed at multiple times into normal cannulated rat brain, produced focal sterile abscesses at the instillation site but no widespread allergic encephalitic reaction. Cells morphologically consistent with TALL-104 cells specifically trafficked from the site of instillation through the neuropil, occasionally into the contralateral brain, and egressed at perivascular and leptomeningeal spaces. In vivo experiments with cannulated rats bearing 9L gliosarcoma showed a preferential localization of the TALL-104 cells in tumor compared with normal brain. Taken together, these data support the concept that TALL-104 cells can be used as a novel nontoxic and efficacious paradigm for cellular immunotherapy trials in human primary malignant brain tumors.

Purified herpes simplex thymidine kinase retroviral particles. II. Influence of clinical parameters and bystander killing mechanisms

High-titer, purified herpes simplex virus thymidine kinase (HSV-TK) retroviral particles, followed with intraperitoneal ganciclovir (GCV) were tested in Fischer rats bearing 1-week established 9L gliosarcomas. 9L cells were infused intracranially through a cannula on day 0, given intracranial infusions of HSV-TK retroviral particles on days 7-12, and given 5 or 10 daily doses of intraperitoneal GCV starting at day 14. Tumor volumetric studies performed on rat brains at day 26 after tumor infusion revealed significant differences in experimental groups receiving HSV-TK retroviral particles plus 10-day GCV or the 100% transduced 9L-TK group receiving GCV versus control groups treated with either buffer, HSV-TK vector, or either 5- or 10-day regimens of GCV alone. The duration of GCV administration and the volume of tumor burden influenced efficacy. Adjuvant dexamethasone did not significantly affect efficacy. Experiments in which 9L rechallenge of animals treated with 9L-TK/GCV or 9L tumors treated with HSV-TK vector/GCV indicated that a host immune response was involved in rejecting the rechallenge tumor. Outcome was dependent upon the site and size of the rechallenge inoculum. In vitro, bystander effects were significant but were especially marked when cell-to-cell contact was maintained. Cumulatively, the data indicate that both the bystander effect and the host immune response are responsible for the efficacy observed in the suicide gene therapy paradigm using purified HSV-TK retroviral particles and GCV to treat smaller tumor burden in rats with 9L gliosarcoma.

Paucity of retinoic acid receptor alpha (RAR alpha) nuclear immunostaining in gliomas and inability of retinoic acid to influence neural cell adhesion molecule (NCAM) expression

Neural cell adhesion molecule (NCAM) is down-regulated during periods of embryological cell migration and may be important in local tumor migration or metastases. Conflicting information exists in the literature about NCAM expression in human glial tumors and little is known about its expression in human brain metastases. We immunohistochemically stained a panel of 43 primary human brain tumors and their cultured counterparts for NCAM including glioblastoma multiformes, anaplastic astrocytomas, oligodendrogliomas, and contrasted their staining with a panel of 3 meningiomas, 11 brain metastases, and 5 normal brain samples utilizing the monoclonal antibody NKH-1. Most gliomas and metastatic melanomas and lung carcinomas showed a high percentage of cells positive for NCAM expression while NCAM staining was negative for other carcinomas. No difference was seen between intensity or percentage of cells that were NCAM positive, based on tumor grade or type. In glioma cell lines, NCAM expression was lost upon passage. In 15 glioma cell lines we also determined NCAM isoform expression by reverse transcription/polymerase chain reaction (RT/PCR) and found that 6 of 15 had message for NCAM 180, 8 of 15 for NCAM 140, and only 3 of 15 had message for NCAM 120. Normal brains always contained message for the 180 isoform and usually had mRNA for all 3 isoforms. Using monoclonal antibodies for retinoic acid receptor alpha (RAR alpha), we found nuclear staining in melanomas and lung carcinomas metastatic to brain and only rarely in gliomas. Neither the relative antigen density of NCAM nor the percent of NCAM-positive cells appreciably changed upon incubation with retinoic acid (RA), as measured by flow cytometry. RAR alpha was not found at a level measurable by immunohistochemistry in nuclei of most glial tumors, providing an explanation for why RA might not induce NCAM expression. Whether paucity of RAR alpha on primary gliomas might also correlate with results from clinical trials showing limited efficacy of RA in treatment of human gliomas awaits further study.

Receptor expression, cytogenetic, and molecular analysis of six continuous human glioma cell lines

Six human glioma cell lines were established from tissues obtained from five patients diagnosed with Kernohan grade IV glioblastoma multiforme and one from a patient with a grade II astrocytoma. One line was from a recurrent patient who had received prior therapy; the other lines were derived from patients at initial diagnosis and/or before cytoreductive therapies other than surgery were given. Considerable variability in phenotypic, karyotypic, and cell surface marker expression was displayed between the six human glioma cell lines. The karyotypes ranged from apparently normal (grade II astrocytoma) to those with complex rearrangements. Trisomy of chromosome 7 was the most common abnormality. The extensive cytogenetic and molecular characterization of these lines may facilitate their utilization in cellular and molecular biologic studies.

Establishment and characterization of a human glioblastoma multiforme cell line

Cell lines provide a useful system for further understanding the biology of glioblastoma multiforme. In this study, a new glioblastoma multiforme cell line, GATAGM-96 (Gulhane Askeri Tip Akademisi-Gliblastoma Multiforme-96), was established from a tumor specimen removed from an 80-year-old male patient who underwent surgery for intracranial tumor. Morphologic examination, immunocytochemical staining, growth kinetics, and karyotypic characteristics of this cell line were studied. The cytoskeleton was positive for neuron-specific enolase, vimentin, and neurofilament, and it was negative for glial fibrillary acidic protein, S-100 protein, p53 protein, epidermal growth factor, and transforming growth factor alpha. Growth kinetic studies demonstrated an approximate population doubling time of 38 to 42 h and a colony forming efficiency of 83.3%. The karyotype of the cells demonstrated it as hyperdiploid, with a large subpopulation of polyploid cells. There were numerous structural and numerical chromosome aberrations; most of them were present as clonal events. The phenotypic and chromosomal features detailed on the GATAGM-96 cell line should make it a useful addition to the cell lines currently available for in vitro and in vivo studies of glioblastoma multiforme.

Overexpression of a transmembrane isoform of neural cell adhesion molecule alters the invasiveness of rat CNS-1 glioma

CNS-1 is a highly invasive neural cell adhesion molecule (NCAM)-positive rat glioma that exhibits similarities in its pattern of infiltration to human gliomas. To investigate whether increasing NCAM expression alters invasive behavior, retroviruses encoding human NCAM 140 and a cytoplasmic truncation of NCAM 140 were used to transduce a population of CNS-1 glioma cells that had a relatively low endogenous level of NCAM. Compared to cells transduced with a control virus, cells overexpressing either intact or truncated human NCAM 140 showed decreased invasion of a reconstituted basal lamina. Changes in growth rate or in key matrix metalloproteinase activities could not account for this result. In a migration assay on type IV collagen, cells exhibited a substrate concentration-dependent increase in the rate of migration; however, overexpression of NCAM 140 or truncated NCAM 140 inhibited motility at higher substrate concentrations. Consistent with these findings was the decreased spread of NCAM 140 overexpressers in vivo following instillation of cells into the right frontal cortex of rat brain. NCAM 140 overexpressers showed considerably more restricted perivascular and periventricular spread than cells transduced with a control virus. However, NCAM-140-overexpressing tumor exhibited a less cohesive pattern of growth near the site of tumor instillation and more individual cell infiltration of brain parenchyma with more pronounced perineuronal satellitosis. The stability of recombinant NCAM expression was confirmed by recovering tumor cells from tumor-bearing animals and measuring NCAM levels by flow cytometry. These observations show that overexpression of NCAM 140 decreases the long-range spread of CNS-1 glioma along basal lamina pathways but enhances local infiltration of neuropil.

Treatment of recurrent glioma with intracavitary alloreactive cytotoxic T lymphocytes and interleukin-2

For a single-dose toxicity assessment, five patients with recurrent malignant glioma (ages 29-46 years) were treated with intracavitary alloreactive cytotoxic T lymphocytes (CTL) and interleukin-2 (IL-2). The trial tested the hypothesis that alloreactive CTL, sensitized to the major histocompatibility complex (MHC) proteins of the patient, offer selective, targeted killing of glioma cells that express MHC. Patient lymphocytes, which also express MHC, were irradiated and placed into CellMax artificial capillary systems with lymphocytes from MHC-disparate donors and CTL developed over a 2- to 3-week period with a low concentration of IL-2. The CTL largely expressed CD3 and CD11a/CD8 markers and lysed targets displaying patient MHC. CTL were implanted into the tumor bed at surgery and a catheter was used for subsequent infusions. Patients received one to five treatment cycles every other month; one cycle generally consisted of two or three CTL infusates administered within a 1- to 2-week period. Different unrelated donors were used for each cycle. Treatment was well tolerated; transient toxicity at grades 1-3 was recorded by NCI Common Toxicity Scale criteria. Two glioblastoma patients have died; one from tumor recurrence locally and the other from recurrence at a site distant from the treatment. Two of the five patients completed five cycles; one anaplastic oligodendroglioma patient shows no evidence of tumor 30 months from the start of immune therapy and an anaplastic astrocytoma patient shows stable disease 28 months after initiation of therapy. One anaplastic oligodendroglioma patient, who dropped the protocol during her second treatment cycle, has no evidence of tumor 28 months after recurrence.

Artificial-capillary-system development of human alloreactive cytotoxic T-lymphocytes that lyse brain tumours

The production of alloreactive cytotoxic T-lymphocytes (CTL) for therapy of recurrent brain tumours was performed in the CELLMAX artificial capillary system composed of cell-culture modules containing cellulose acetate or cuprammonium rayon hollow fibres. Lymphocytes, obtained from the brain-tumour patient to be used for sensitization, were stimulated with OKT3 (anti-CD3) and interleukin-2 (IL-2) and inoculated into the extracapillary space of artificial capillary modules. For allogeneic CTL production, the expanded patient lymphocytes were harvested, irradiated and placed into a second artificial capillary system with allogeneic lymphocytes from a healthy donor. In a one-way mixed lymphocyte reaction, CTL developed in the presence of low-concentration IL-2 (60 i.u. of IL-2/ml). In 18-21 days the cell preparation usually displayed a predominantly CD3+, CD8+ phenotype, which consorted with the dual-labelled CD8/CD11a markers used to identify CTL. Chromium (Cr)-release assays demonstrated lysis of patient tumour in relation to allogeneic glioma; the response observed in cold-target-inhibition assays confirmed lysis of the relevant tumour by the CTL.

Purified herpes simplex thymidine kinase Retrovector particles. I. In vitro characterization, in situ transduction efficiency, and histopathological analyses of gene therapy-treated brain tumors

Replication-defective, highly purified retroviral vectors (Retrovector), at titers of 10(8) colony forming units/mL, were prepared that conferred either beta-galactosidase or herpes simplex thymidine kinase (HSV-TK) activity. 9L gliosarcoma cells, transduced efficiently in vitro, were highly sensitive to ganciclovir (GCV). The mean frequency of in situ transduction, measured by flow cytometry of single-cell tumor suspensions isolated from rat brains, was 3.2 +/- 0.6%; similar assessments were made by staining of beta-galactosidase or by immunohistochemistry with anti-HSV-TK. In vitro HSV-TK-transduced and G418-selected 9L-TK gliosarcoma tumors treated with GCV were eradicated in approximately 53% of the animals (10/19) at day 26, however, 89% (17/19) histologically showed < 1% tumor volume. Histologic evaluation at day 26 of animals with established 9L tumors treated with intralesional injection of HSV-TK vector followed by GCV treatment showed that 29% (4/14) had no tumor; 50% (7/14) had < 1% tumor volume. Regression of tumors proceeded over the time since the complete rate was increased at day 60. Neither HSV-TK vector particles nor GCV alone altered the histological profile of 9L tumors, but substantial numbers of CD4+ and CD8+ lymphocytes infiltrated the tumors of animals treated with both. In cured animals, the former tumor bed contained cell debris, immune cells, and fibroblasts and was without damage to adjacent brain. The efficacy of suicide gene therapy for rat gliosarcoma using highly purified virion vectors approaches that of packaging cell lines.

Neural cell adhesion molecule expression in human pituitary adenomas

Neural cell adhesion molecule (NCAM) is a cell surface glycoprotein whose expression may be important in metastatic or local growth of neoplasms. Expression of NCAM in human pituitary adenomas was assessed on snap-frozen and Bouin's and/or formalin-fixed, paraffin-embedded archival tissue using a sensitive alkaline phosphatase-antialkaline phosphatase method of immunostaining with the monoclonal antibody, NKH-1. The 20 pituitary adenoma patients consisted of 13 males and 7 females, ages 19-78 years, with null cell macroadenomas (3), plurihormonal macroadenomas (4), weak gonadotropic macroadenomas (5), growth hormone-prolactin adenomas (2), and prolactinomas (6). Eight of the adenomas were clinically invasive. The snap-frozen material from 14 pituitary tumors showed immunostaining for NCAM in either a cytoplasmic, peripheral membranous, or mixed pattern; 2 of 3 prolactinomas showed patchy immunostaining. The Bouin's and/or formalin-fixed pituitary adenoma specimens from 6 clinically invasive cases showed less distinct NCAM localization but 4 out of 6 showed diffusely positive NCAM immunostaining, with greatest intensity appreciated on the Bouin's-fixed tissue. There was no correlation between NCAM staining pattern and invasive characteristics of the tumors. These results suggest that NCAM expressivity is not a useful marker for assessing pituitary adenoma tumor invasiveness.

Migration of activated lymphocytes when adoptively transferred into cannulated rat brain

Migration of fluorescent DNA-labeled or 111Indium-labeled activated lymphocytes was studied in normal rat brain bearing surgically implanted cannulas. The migration of allogeneic cytotoxic T lymphocytes (CTL), derived from the DA rat (DA anti Fischer CTL), and of syngeneic concanavalin A (ConA)-activated lymphocytes (Fischer Con A blasts), was determined in Fischer rats between 2 h and 7 days post instillation into parietal brain. Whole body nuclear imaging indicated that the majority of the radiolabeled lymphocytes, either syngeneic or allogeneic, were present in the brain at 2 and 18 h. Autoradiography of brain slices demonstrated that label was located throughout the brain and in both hemispheres at all time points. By direct tissue radioassay, approximately 60% of the injected dose was present between 2 and 18 h; this decreased to 18% by day 7. By fluorescence microscopy, large numbers of lymphocytes were visible up to 3-4 days. The lymphocytes traveled from the instillation site into both cerebral hemispheres primarily following white matter tracts. Preferential localization of fluorescently labeled lymphocytes was seen in the corpus callosum, internal and external capsules, anterior commissures, lateral olfactory tracts, white matter connections in the caudate and putamen, mammillothalamic and optic tracts. Overall, gray matter contained fewer cells although perivascular spaces within it had high concentrations of cells, indicating these spaces may act as points of egress.

Intracranial administrations of single or multiple source allogeneic cytotoxic T lymphocytes: chronic therapy for primary brain tumors

Previous investigations by our group demonstrated the efficacy of single source allogeneic cytotoxic T lymphocytes (CTLs) given multiple times in reducing or curing tumor burden in the rat 9L gliosarcoma model. In this study, the lack of toxicity to normal brain when single source allogeneic CTLs were intracranially administered multiple times is documented. Additionally, the efficacy and lack of toxicity of allogeneic CTLs from multiple sources, each given once is documented. CTLs sensitized to Fischer antigen were prepared from major histocompatibility complex incompatible DA, PVG, Sprague-Dawley and Wistar-Furth rat lymphocytes. CTLs from multiple donors were administered one time each to Fischer rats bearing established 9L tumor at staggered intervals over a two week period and survival was monitored in relation to a sham treated group. Additional groups of nontumor-bearing rats received either multiple source allogeneic CTLs or single source DA anti Fischer CTLs in the same treatment regimen. Histological evaluation of the nontumor-bearing brains receiving either single or multiple source allogeneic CTL infusions showed minimal localized brain damage confined to the cannulation tract. No neuronal loss or inflammatory reaction was seen either adjacent to or remote from the administration site. Brains from the long-term survivors of the tumor-bearing animals showed no residual neoplasm; the instillation site had focal sterile abscesses; gliosis and neuronal loss did not extend into adjacent brain. The safety and potential of chronic, local allogeneic CTL administration, derived from multiple donors, as adjuvant local therapy for brain tumors was demonstrated.

A 9L gliosarcoma transplantation model for studying adoptive immunotherapy into the brains of conscious rats

A rat model for brain tumor immunotherapy is described that closely mimics the type of treatment that could be administered to humans. It involves surgical implantation of a permanent cannula in the brain, through which tumor cells and various effector cells and/or cytokines can be injected. The advantage of this system over more conventional animal surgical procedures is that conscious animals can be treated multiple times while avoiding morbidity and mortality associated with reoperative procedures. Using this system to study adoptive immunotherapy for brain tumors, we provide evidence that the 9L gliosarcoma tumor from the Fischer rat strain can be reduced or destroyed in situ following adoptive immunotherapy with specifically activated cytotoxic T lymphocytes.

A rat glioma model, CNS-1, with invasive characteristics similar to those of human gliomas: a comparison to 9L gliosarcoma

A glioma cell line, CNS-1, was developed in the inbred Lewis rat to obtain a histocompatible astrocytoma cell line with infiltrative and growth patterns that more closely simulate those observed in human gliomas. Rats were given weekly intravenous injections for a six month period with N-nitroso-N-methylurea to produce neoplasm in the central nervous system. Intracranial tumor was isolated, enzymatically and mechanically digested, and placed into culture. The tumor cell line injected subcutaneously on the flanks of Lewis rats grew extensively in situ as cohesive tumor masses but did not metastasize. Intracranially, CNS-1 demonstrated single cell infiltration of paranchyma and leptomeningeal, perivascular, and periventricular spread with expansion of the tumor within choroid plexus stroma. CNS-1 cells titrated in right frontal brain of Lewis rats at 10(5), 5 x 10(5), 10(5), 5 x 10(4) cells per group had mean survival times ranging from 20.5 to 30.2 days. CNS-1 was immunoreactive for glial fibrillary acidic protein, S100 protein, vimentin, neural cell adhesion molecule, retinoic acid receptor alpha, intercellular adhesion molecule, and neuron specific enolase. The CNS-1 cells commonly had one or more trisomies of chromosomes 11, 13 or 18; losses, possibly random, of chromosomes (3, 5, 19, 30, X or Y) were noticed, and a marker chromosome made up of approximately 3 chromosomes was usual. Comparisons of CNS-1 to 9L gliosarcoma tumor were made. The glial CNS-1 tumor model provides an excellent system in which to investigate a variety of immunological therapeutic modalities. It spreads within brain in a less cohesive mass than 9L and is accepted without rejection in non-central nervous system sites by Lewis rats.

Alveolar soft part sarcoma: an unusually long interval between presentation and brain metastasis

While alveolar soft part sarcoma is an uncommon soft tissue tumor known for late metastases to lung, bone, and brain, and interval of 33 years between primary presentation and development of brain metastasis has not been described. We document a patient with a removal of an alveolar soft part sarcoma from the pectoralis major muscle at the age of 10 years, a lung metastasis at the age of 31 years, and brain and renal masses at the age of 43 years. The patient received surgical resections each time, but never radiotherapy or chemotherapy. He is currently alive and well. Immunohistochemistry, karyotypic analysis, flow cytometry, and gene expression were analyzed on primary tumor and established cell cultures in the hopes of further elucidating the histogenesis of this unusual neoplasm.

Systemic chemotherapy combined with local adoptive immunotherapy cures rats bearing 9L gliosarcoma

Survival of Fischer rats bearing 9L gliosarcoma in the brain was measured to determine the efficacy of 1) systemically administered chemotherapy with local adoptive immunotherapy (chemo-adoptive immunotherapy) or 2) systemically administered chemo-immunotherapy. Winn assays, where tumor instillation coincided with the start of treatment, and one-week established tumor assays were conducted. Survival of chemo-adoptive immunotherapy treated groups given intraperitoneal cyclophosphamide and intracranial lymphokine activated killer cells and recombinant Interleukin-2 was significantly extended when compared to sham treated control groups, to groups given chemotherapy with intraperitoneal cyclophosphamide, and to groups treated by local adoptive immunotherapy with intracranial lymphokine activated killer cells and Interleukin-2. The killer cells were generated from spleens of donor rats that either had or had not been given cyclophosphamide 24 h earlier. Long-term survivors (9/39), sacrificed at day 70, were obtained only in the chemo-adoptive immunotherapy treated groups; 7/39 had no histologic evidence of tumor and had focal sterile abscesses at the site of killer cell instillation. Average group weight plotted over time showed that there was acceptable toxicity with chemo-adoptive immunotherapy; the toxicity was identical to that obtained with systemic cyclophosphamide treatment. In contrast, survival of chemo-immunotherapy treated groups given systemic cyclophosphamide and Interleukin-2 was not significantly extended from groups which were sham treated or treated only with systemic Interleukin-2. Rapid decline of average group weight plotted over time and early deaths following chemo-immunotherapy treatment indicated that the regimen was toxic. The effect of cyclophosphamide administration on the splenocytes of donor rats and the LAK cells generated from them was determined by in vitro studies analyzing cell number, viability, phenotypic expression and cytotoxicity against 9L tumor. In the treatment of this intracranial neoplasm, the beneficial effects of cyclophosphamide were determined to occur in situ in the tumor-bearing host. No benefit resulted from cyclophosphamide treatment of donor rats that supplied splenocytes for LAK cell production.

Characterization of a continuous human glioma cell line DBTRG-05MG: growth kinetics, karyotype, receptor expression, and tumor suppressor gene analyses

The establishment of a new glioma cell line, DBTRG-05MG, in a modified RPMI 1640 medium is described. The cells were derived from an adult female with glioblastoma multiforme who had been treated with local brain irradiation and multidrug chemotherapy; the tumor showed substantial change in histologic appearance compared to the original biopsy 13 mo. previously. The line has been successfully cryopreserved and passaged up to 20 times. The karyotype of the cells demonstrated it as a hypotetraploid line; the DNA index of 1.9 confirmed the karyotype analyses. By immunocytochemical analysis, the cell line reacted with polyclonal antibodies to vimentin, S100, and neuron specific enolase, reflecting its primitive neuroectodermal character. Positive immunostaining for epidermal growth factor receptor correlated with the excess of chromosome 7 seen in the karyotype. The cell line reacted negatively to antibodies against platelet-derived growth factor and its receptor, neuronal cell adhesion molecule, and glial fibrillary acidic protein. By flow cytometry, the cells were major histocompatibility class I antigen positive and class I antigen negative. Growth kinetic studies demonstrated an approximate population doubling time of 34 to 41 h and a colony forming efficiency of 71.4%. Western blot analysis showed the presence of low levels of normal-sized retinoblastoma protein. When compared to the patient's lymphocyte DNA, no loss of heterozygosity of the p53 tumor suppressor gene was observed in the DBTRG-05MG cell line DNA.

Allogeneic tumor-specific cytotoxic T lymphocytes

We report the development of cytotoxic T lymphocytes specific for an allogeneic brain tumor in a rat model. DA strain cytotoxic T cell precursors stimulated by an allogeneic tumor (9L gliosarcoma) from the Fischer rat could generate a population of cytotoxic T lymphocytes that lysed the allogeneic 9L tumor but failed to lyse other targets, including Fischer concanavalin-A(ConA)-stimulated lymphoid blast targets. DA T cells depleted of reactivity to the Fischer haplotype (DA-F) retained reactivity to the 9L tumor, demonstrating that T cell precursors with specificity for normal Fischer alloantigens were not required for the generation of a response to the 9L Fischer tumor. The preferential lysis of the tumor target did not simply reflect a higher density of Fischer target antigens on the tumor than that found on normal Fischer ConA blast targets. First, the relative densities of class I antigen on the 9L tumor and normal Fischer ConA blasts were comparable. Second, cytotoxic T cells could not be generated from DA-F precursors when Fischer ConA blasts were used as stimulators. If DA-F T cells were simply responding to the higher density of Fischer antigen found on 9L tumor, it would have been expected that the ConA blasts expressing comparable levels of antigen to that found on the tumor would have generated cytotoxicity for both the 9L and ConA targets. We conclude that the cytotoxic T cells are specific for a determinant expressed only by the tumor. Such tumor-specific cytotoxic T cells could be useful in vivo for adoptive immunotherapy of brain tumors.

Secondary screening system for preclinical testing of human lung cancer therapies

The National Cancer Institute has instituted a primary screening system for testing new agents against cultured cancer cell lines. The purpose of this study was to determine the feasibility of using a nude rat orthotopic (organ-specific) human lung cancer model system as an in vivo secondary screen for general evaluation of new anticancer agents and therapies active against lung cancer. To make this determination, we tested whether this system allows measurement of uptake and tumoricidal activity of anticancer therapies. Tumor-bearing lungs from 53 Rowett nude rats with orthotopically implanted human large-cell undifferentiated lung carcinoma (NCI-H460) were perfused ex vivo for 1 hour with or without each of two anticancer modalities. Lungs were perfused with blood-free perfusate alone (untreated control), perfusate with 100 micrograms/mL doxorubicin (treated positive control), or perfusate with lymphokine-activated killer cells plus human recombinant interleukin-2 (LAK/rIL-2). Weight gain during perfusion was the criterion used to quantitate lung injury. Treatment efficacy was measured by clonogenic assay after enzymatic disaggregation of the perfused tumors. Doxorubicin levels in the tumor and in the uninvolved lung were measured by high-performance liquid chromatography. Both treatment groups showed only slight increases in lung weight compared with that in the untreated control group, suggesting good lung tolerance of the procedure. Lung and tumor levels of doxorubicin were 320 +/- 21 ng/mg of tissue and 32 +/- 5 ng/mg of tissue (means +/- SE), respectively. Clonogenic assay demonstrated a fivefold to 10-fold reduction in the surviving fraction of tumor cells with doxorubicin but no change with LAK/rIL-2.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytotoxicity against autologous, allogeneic, and xenogeneic tumor targets by human recombinant interleukin-2-activated lymphocytes from healthy dogs and dogs with lung tumors

Before dogs with lung tumors were treated by adoptive immunotherapy, the ability of canine blood lymphocytes (PBL) from the peripheral circulation to differentiate in vitro in the presence of human recombinant interleukin-2 (rIL-2) and become tumoricidal was investigated. The PBL from healthy dogs (n = 6) and dogs with lung tumors (n = 5) were grown in culture medium alone, in the presence of rIL-2 to generate lymphokine-activated killer (LAK) cells, or with phytohemagglutinin (PHA) and rIL-2 to generate autologous-stimulated lymphocytes (ASL). After 4 days, cytotoxicity by the ASL, LAK, and PBL was determined in a 4-hour 51chromium-release assay. Target cells in the assay were short-term cultured enzyme digests of autologous (self), allogeneic (genetically different) primary tumors, and Raji, the xenogeneic human lymphoma cell line. The PBL cultured without rIL-2 were not cytotoxic against any tumor. However, when a dog's PBL were activated in vitro, they killed the dog's own tumor, ASL more effectively than LAK cells. Pulmonary adenocarcinomas and an osteosarcoma metastasis to lung were among the autologous tumors assayed. Against an allogeneic canine osteosarcoma, ASL generated from healthy dogs were significantly more cytolytic than LAK from healthy dogs, or than ASL generated from tumor-bearing dogs. Cytotoxicity was greater against allogeneic tumor than against Raji. Lectin-dependent cellular cytotoxicity, tested by including PHA in the assay medium with lymphocytes and Raji cells, by ASL and LAK was greater than cytotoxicity of Raji without PHA. Because ASL were more cytolytic than LAK against all targets in vitro, they may be more beneficial than LAK for immunotherapy of canine tumors.

Analysis of interleukin 2 and various effector cell populations in adoptive immunotherapy of 9L rat gliosarcoma: allogeneic cytotoxic T lymphocytes prevent tumor take

Recombinant interleukin 2 (rIL-2) and various effector cell populations were used for adoptive immunotherapy in the Fischer strain 9L rat gliosarcoma model. The in vivo cytotoxicities of nonspecifically activated lymphocytes and specifically activated cytotoxic T lymphocytes (CTLs) were assessed in a modified in vivo neutralization (Winn) assay. Effector cells (10(6)) and 9L tumor cells (10(5] were combined with 10(4) units of rIL-2 and stereotactically implanted into the right frontal centrum semiovale of the Fischer (F344) rat. At 7 and 14 days, additional effector cells (10(6] and rIL-2 (10(4) units) were administered through the same burr hole. Nonspecifically activated splenocytes were lymphokine-activated killer (LAK) cells, both plastic-adherent and nonadherent, whereas specifically activated CTLs were either syngeneic (genetically identical) or allogeneic (genetically dissimilar). Syngeneic CTLs were T lymphocytes from Fischer rats primed in vivo with 9L cells and restimulated in vitro. Allogeneic CTLs were generated by exposing DA rat lymphocytes either to irradiated Fischer lymph node cells or to 9L Fisher tumor cells in vitro. Control groups included rats bearing 9L tumor who were untreated, those who received peripheral (i.p. or s.c.) administration of rIL-2, or those who received syngeneic unstimulated T lymphocytes and rIL-2. For a set of animals given the same inoculum of 9L tumor, significantly improved survival was shown for groups treated with nonadherent or adherent LAK cells (P less than or equal to 0.0003), syngeneic CTLs (P = 0.0327), or allogeneic CTLs (P = 0.0025) over untreated control animals by using Mantel-Haenzel nonparametric logrank equations. Only treatment with allogeneic CTLs prevented tumor take.

Bioactivity of electric field-pulsed human recombinant interleukin-2 and its encapsulation into erythrocyte carriers

The molecular integrity of human recombinant interleukin-2 (rIL-2), as measured by size exclusion chromatography, was not altered when exposed to high electrical field intensities. In addition, the biological activity was unaffected, as evidenced by the ability of the rIL-2 to stimulate the proliferation (by cell growth assays and tritiated thymidine uptake) and differentiation (by cytotoxicity assay) of human lymphocytes into killer cells. Electroporation conditions chosen for the loading of rIL-2, based upon those which provided for good recovery of carriers and minimal hemoglobin release, involved a lower field intensity (i.e., 6 kV/cm instead of 7 or 8 kV/cm) and multiple pulses (eight pulses, 5 microseconds) rather than a single pulse (40 microseconds). Human erythrocyte carriers consistently encapsulated 5-7.5% of the rIL-2 by electroporation (6 kV/cm, eight pulses, 5 microseconds duration). A rIL-2 concentration of 600,000 U/ml surrounding the erythrocytes during loading resulted in ca. 245,000 U/ml carriers, which represents a therapeutically significant quantity. Thus, rIL-2 shows potential as an encapsulated agent for slow release in the erythrocyte carrier system.

Lymphokine-activated killer cells with interleukin-2: dose toxicity and localization in isolated perfused rat lungs

Lymphokine-activated killer (LAK) cells combined with recombinant interleukin-2 (rIL-2) can produce tumor regression in murine models and in patients with pulmonary metastatic disease. However, the dose escalations of rIL-2 required for optimal therapeutic effect often result in increased vascular permeability ("vascular leak syndrome") and other toxic systemic consequences. To avoid systemic distribution, lung perfusion was used to administer LAK and rIL-2 locally. Preliminary to using these agents to treat tumor-bearing lungs, we used a nonblood-perfused isolated rat lung model to study the localization of radiolabeled rIL-2 and LAK and to characterize effects on normal lung tissue of increasing dosages and exposure times of rIL-2 and LAK cells, individually and combined. Lung function or permeability was assessed by measuring lung weight gain and pulmonary arterial pressure during the perfusion, extravascular lung water by double indicator dilution techniques, and wet weight to dry weight ratio. After perfusion for 1 hour using 200,000 U (1,300 U/ml) rIL-2, injury was detected as visible pulmonary edema, weight gain and increases in wet to dry weight ratio, and extravascular lung water; no injury was detected at lower, clinically appropriate dosages. When 1 X 10(8) LAK cells combined with 100,000 U rIL-2 (666 U/ml) were perfused for up to 2 hours, no injury was ascertained. Uptake and distribution of the radiolabeled rIL-2 or LAK was uniform to all lung lobes and corresponded to the decrease of 12% of the rIL-2 or 50% of the LAK from the perfusate after 1-hour perfusion.

Methotrexate loading of red cell carriers by osmotic stress and electric-pulse methods: ultrastructural observations

Transmission and scanning electron microscopy (EM) of osmotically stressed and electrically pulsed human erythrocyte carriers indicated that the mode of uptake of methotrexate (MTX) varied depending on the method of carrier production. The preswell and electroporation loading methods, apparently by facilitating passive diffusion across the cell membrane, promoted incorporation of the MTX directly into the cytoplasm of the carriers, as evidenced by their variable electron densities. The preswell method produced carriers displaying leptocytic characteristics, whereas the electroporation method produced carriers exhibiting sphero- and stomatocytic transformation. Hypotonic dialysis-prepared carriers took up MTX primarily by endocytosis and secondarily by passive diffusion. Endocytotic activity was not induced by the MTX. Scanning EM revealed that most of the dialysis-prepared carriers exhibited prominent invaginations of the cell surface. Transmission EM of serial thin sections through these carriers revealed numerous fully internalized, membrane-bound vesicles. Endocytotic activity caused progressive loss of membrane and resulted in the sphero- and stomatocytic transformation of the carriers.

Interleukin-2-activated lymphocytes from brain tumor patients. A comparison of two preparations generated in vitro

Two preparations of human recombinant interleukin-2 (rIL-2)-activated lymphocytes from patients harboring malignant brain tumors were characterized as autologous-stimulated lymphocytes (ASL) and lymphokine-activated killer (LAK) cells. ASL were generated from Ficoll-Paque-isolated, nonadherent, defibrinated peripheral blood lymphocytes (PBL) that were stimulated overnight with phytohemagglutinin (PHA) and cultured with rIL-2 (100 U/ml) for 10 days. LAK cells were produced by culturing all PBL in rIL-2 (500 U/ml) for 4 days. In 4-hour chromium release assays, LAK cells showed greater cytotoxicity than ASL against natural killer (NK)-sensitive and NK-resistant tumor cell lines; by 18 hours, the effectiveness of ASL equaled that of LAK cells. By electron microscopic study, PBL, LAK cells, and ASL showed differences. The helper/inducer to suppressor/cytotoxic ratio (T4+/T8+) of PBL, LAK cells, and ASL was 1.1:1, 1.0:1, and 0.4:1, respectively. ASL, when compared with PBL or LAK cells, have a significantly higher percentage of MO1+/DR+ and T8+/9.3+ subpopulations. ASL and LAK cells, used for the therapy of gliomas, are distinct.

The role of toxic oxygen metabolites in interleukin-2-induced vascular leak syndrome

We demonstrated that IL-2 causes injury by a blood mediator not by a direct action on endothelial cells and that toxic oxygen metabolites may play a role.

Mouse erythrocyte carriers osmotically loaded with methotrexate

The mouse red blood cell (RBC) and red blood cell ghost (RBCG) have been studied as carriers of methotrexate (MTX). When incubated with high concentrations of MTX, RBCs take up significant quantities of it. However, when active loading techniques, such as the slow dialysis and preswell methods, are applied to those cells, up to 15 times more MTX can be entrapped. We have studied factors critical to the incorporation, leakage, and morphology of RBCGs during their loading with MTX by the slow dialysis and preswell methods. Compounds added to the buffers to maintain the ATP content of the cells and osmolarity play functional roles in this process. The fate of the material entrapped within the ghosts after in vivo administration was shown to be capture by the reticuloendothelial system. The pharmacological efficacy of MTX-loaded RBCGs in treating mice bearing hepatoma ascites tumors was demonstrated by increases in average survival time of 28.5-42.8%.

Thirty year experience with predictive lumbar sympathectomy. Method for selection of patients

An office or bedside procedure to predict benefit from or contraindications to lumbar sympathectomy has been presented. Significant benefit and no instance of paradoxic gangrene occurred in an experience of more than 30 years with the test. This personal series of over 70 patients illustrates significant benefits, including healing of gangrenous digits, successful ray (transmetatarsal) amputation, and relief of ischemic rest pain in selected patients, even in the absence of femoral (groin) pulses. A criterion of an increase of 2 degrees or more in skin temperature of the ipsilateral great toe after lumbar sympathetic block at the approximate levels of the second, third, and fourth lumbar vertebrae has proved to be an adequate parameter or indication of subsequent benefit from surgical lumbar sympathectomy. A favorable response is predictable by the method described.

Characterization of a glycoprotein fusogen isolated from Sendai virus

After isolation from Sendai virus, the glycoproteins HN and F retained their ability to induce hemagglutination and both heterologous and homologous cell-cell fusion. Both methods for demonstrating cell fusion indicated that the isolated HN and F glycoproteins compared favorably with whole Sendai virus as a fusogen. Conditions affecting the degree of fusion were examined and optimized. Whole virus and isolated glycoprotein preparations were characterized by electron microscopy and by SDS-polyacrylamide gel electrophoresis. Lipid analysis of the glycoprotein preparations by thin layer chromatography and gas chromatography/mass spectrometry indicated that they were partially lipid-depleted during the isolation protocol and the ratio of cholesterol to phospholipid was higher than in the whole virus. A complete fatty acid analysis was performed on lipid extracts from whole virus and from glycoprotein preparations. Detergent was removed from the glycoproteins by dialysis and by incubation with Amberlite XAD-2 resin. The detergent content of the glycoprotein preparations was monitored by gas chromatography and with [3H]Triton X-100. Both methods showed that virtually all (greater than or equal to 99.8%) of the originally added detergent was removed. Electron microscopy of the negatively-stained HN and F preparations showed primarily spherical particles 120 +/- 20 A in diameter (range 80-250 A). Since no organization reminiscent of envelopes could be demonstrated, we conclude that the fusogenic activity of Sendai virus resides in the glycoproteins per se rather than in bilayer integrated lipid-protein complexes.

Stability of erythrocyte ghosts: a gamma-ray perturbed angular correlation study

The structural integrity of erythrocyte ghosts made by the preswell and slow-dialysis techniques has been studied in vitro by use of gamma-ray perturbed angular correlation (PAC) techniques and also by standard in vitro leakage methods employing sequestered labeled markers. Complexes of 111In3+ and nitrilotriacetate were encapsulated in ghosts made from human, rabbit, rat, and mouse erythrocytes, and their leakage was monitored by both methods. In addition, 125I-labeled bovine serum albumin was encapsulated, and ghost integrity was monitored by conventional leakage measurements. With the PAC technique the percentage of material released from human ghosts was determined quantitatively, and the results were equivalent to those obtained by the conventional method. In addition, at various times after intravenous injection, tissue distribution of the ghosts in the mouse was studied. The percent injected dose per gram of tissue of the labeled surface proteins of erythrocyte ghosts in circulation approximated that of the entrapped labeled albumin. This suggests that the ghost membrane and contents are strongly associated in vivo. Large 125I-labeled bovine serum albumin molecules and small 111In3+-nitrilotriacetate complexes were delivered in high quantitites to the lung initially, and to the liver and spleen. Because erythrocyte ghosts have the ability to entrap a wide range of substances and deliver them to specific organs, ghosts may be preferable to other drug carriers or drug therapy for treatment of certain disorders.

Microinjection of arginase into enzyme-deficient cells with the isolated glycoproteins of Sendai virus as fusogen

A method of introducing enzymes into the cytoplasm of fibroblasts in culture is described. Erythrocytes obtained from normal and arginase-deficient individuals were loaded with arginase in vitro and fused to arginase-deficient mouse and human fibroblasts. Erythrocyte ghost-fibroblast fusion was quantified by a 14C-radioactive assay for arginase in solubilized fibroblasts. Fusion was successfully induced by Sendai virus and also by the isolated glycoproteins of Sendai virus. After fusion the arginase activity associated with the Fibroblasts was 700--1500 U of arginase/mg of cell protein; this enzyme activity was 5- to 10-times higher than that normally found in the fibroblasts. The enrichment in arginase activity indicated that between four and ten ghosts had fused per fibroblast. The use of isolated viral proteins to mediate the transfer of enzymes into cells in vivo might alleviate clinical complications inherent in the use of whole virions. The enzyme replacement technique described in this report for a hyperargininemic model cell system should be applicable to the group of inborn errors of metabolism characterized by deficiency of an enzyme normally localized in the cytoplasmic compartment of cells.

An evaluation of bilateral breast carcinoma. Simultaneous and sequential lesions

The detection of bilateral breast carcinoma, simultaneous or nonsimultaneous, appears to be increasing. Undoubtedly a major factor in this is the increased use of mammography and xeromammography. In a 21-year period at Saint John's Hospital and Health Center, 1,189 cases of primary breast carcinoma were treated, of which 34 (2.9 percent) were bilateral. However, from 1972 to 1974 the incidence has risen from 1.9 to 10.8 percent, with a simultaneous rise in numbers of xeromammograms made. Xeromammography should be done routinely in patients in whom carcinoma of the breast is suspected. Its use should also be an integral part of the follow-up in patients in whom mastectomy has been carried out previously.