Immunobiology of primary intracranial tumors. Part 8: Serological responses to active immunization of patients with anaplastic gliomas

Combining locoregional CAR-T cells, autologous + allogeneic tumor lysate vaccination and levamisole in treatment of glioblastoma

Glioblastoma multiforme (GBM) is an aggressive brain malignancy and harbors a microenvironment limiting immune cells activity. CAR-T cells are being tested in the treatment of cancers and there exist reports which demonstrate dramatic regression of multicentric GBMs following intrathecal treatment with CAR-T cells. In this article, a triple approach for immune treatment of GBM is proposed. First, GBM tumor specimens for each patient will be saved and cultured to obtain tumor lysates. Then, levamisole will be applied, which possesses immunostimulating, anti-glycolytic, and anti-angiogenic features. Following priming the immune system, GBM patients will be injected with lysates of their own tumor cells plus lysates from a GBM cell line, U251. After 3 months of this treatment, CAR-T cells (transduced with IL13Rα2-CAR) will be applied via intratumoral approach. As such, genetically-modified and native immunocytes may 'meet' in the vicinity of deeply-invading tumor cells and demonstrate greater efficacy via cell-cell interactions. By this, a self-propagating cyclic process - a cancer-immunity cycle - may be initiated to eradicate cancer cells.

Immunotherapy of brain cancers: the past, the present, and future directions

Treatment of brain cancers, especially high grade gliomas (WHO stage III and IV) is slowly making progress, but not as fast as medical researchers and the patients would like. Immunotherapy offers the opportunity to allow the patient's own immune system a chance to help eliminate the cancer. Immunotherapy's strength is that it efficiently treats relatively small tumors in experimental animal models. For some patients, immunotherapy has worked for them while not showing long-term toxicity. In this paper, we will trace the history of immunotherapy for brain cancers. We will also highlight some of the possible directions that this field may be taking in the immediate future for improving this therapeutic option.

Immunotherapy of prolactinoma with a T helper 1 activator adjuvant and autoantigens: a case report

OBJECTIVE

To date, efforts to reliably manipulate the immune system to promote tumor regression in the brain have been disappointing. We report a unique experience of successful immunotherapy to treat a pituitary macroprolactinoma.

METHODS

A 31-year-old woman with an established history of pituitary macroprolactinoma who had undergone tumor resection followed by radiation was admitted to our clinic. The diagnosis had been made due to the patient's symptoms, a serum prolactin (PRL) level of 29,600 mIU/l, a brain MRI revealing a 23 x 19 x 18 mm pituitary mass and a positive PRL immunohistochemistry of the mass. Six months following surgery, she reexperienced headache, excessive sweating and a serum PRL concentration of 2,960 mIU/l despite receiving 30 mg/day bromocriptine. Brain MRI revealed a pituitary mass (3 x 6 x 8 mm) compatible with a pituitary adenoma. Twenty micrograms per milliliter of G2 (as a T helper 1 activator adjuvant) was inoculated intradermally once per week for 24 consecutive weeks (each injection contained 10 mug of G2). The autoantigens were inoculated at the same time with G2.

RESULTS

After immunotherapy, serum PRL concentration decreased to 82 mIU/l, the patient's symptoms disappeared, skin thickness increased to normal and bromocriptine dosage was tapered to 20 mg per week. A follow-up brain MRI revealed almost complete disappearance of the tumor. The patient does not complain of any problems at 1-year follow-up.

CONCLUSION

Activation of both nonspecific (natural killer cells) and specific (cytotoxic T lymphocytes) immunity in relation to the T helper 1 cytokine network is a promising strategy for the treatment of tumors of the central nervous system in humans, especially pituitary macroprolactinomas.

MTH-68/H oncolytic viral treatment in human high-grade gliomas

Application of virus therapy to treat human neoplasms has over a three decade history. MTH-68/H, a live attenuated oncolytic viral strain of the Newcastle disease virus, is one of the viruses used in the treatment of different malignancies. Here we report on the administration of MTH-68/H to patients with glioblastoma multiforme, the most common and most aggressive neuroectodermal neoplasm with a poor prognosis, averaging six months to a year. Four cases of advanced high-grade glioma were treated with MTH-68/H after the conventional modalities of anti-neoplastic therapies had failed. This treatment resulted in survival rates of 5-9 years, with each patient still living today. Against all odds, each patient resumed a lifestyle that resembles their previous daily routines and enjoys a good quality of life, Each of these patients has regularly received MTH-68/H as their sole form of onco-therapy for a number of years now without interruption.

Cell-mediated immunotherapy: a new approach to the treatment of malignant glioma

BACKGROUND

The dismal prognosis for patients harboring intracranial gliomas has prompted an intensive search for effective treatment alternatives such as immunotherapy. Our increased knowledge in basic immunology, glioma immunobiology, and molecular biology may lead to the development of effective, rational immunotherapy approaches.

METHODS

The authors reviewed the literature on glioma immunology, the status of tumor vaccine therapy and on novel techniques to monitor the tumor-specific immune response.

RESULTS

Experimental conditions currently exist whereby potent antitumor cell-mediated immune responses can be generated. However, clinically, no therapeutic regimen has proven effective. Obstacles to establishing an effective immunotherapy regimen are the lack of a well-defined glioma-specific antigen, the heterogeneity of tumor cells in gliomas, and the modulating effect of the glioma itself on the immune system. Unique strategies to overcome these barriers are being developed.

CONCLUSIONS

Novel strategies to generate an anti-glioma immune response through use of dendritic cell vaccination, directed cytokine delivery, gene-based immunotherapy, and reversal of tumor-induced immunosuppression are promising. These strategies carry the potential of overcoming the resistance of gliomas to immunotherapeutic manipulation and, undoubtedly, will become a part of our future therapeutic armamentarium.

Identification of tumor-specific antibodies in patients with breast cancer vaccinated with gene-modified allogeneic tumor cells

Thirty HLA-A2 women with metastatic breast cancer received up to 14 vaccinations with MDA-MB-231-CD80, an HLA-A2 allogeneic breast cancer cell line, which had been lipofected with the cDNA for the CD80 costimulatory molecule. Tumor cells were administered with BCG or GM-CSF as an adjuvant. Sera obtained before and after vaccination were analyzed for antibodies to tumor cell lysate, MUC1, HER2/neu and p53. Since the cell line was grown in fetal bovine serum (FBS), sera were also analyzed for antibodies to FBS. Eighteen of 24 patients for whom sera were available exhibited anti-FBS activity at baseline. Eleven of these 18 patients and all six patients without baseline anti-FBS activity showed an increased titer after vaccination. The anti-FBS activity required that serum samples be absorbed in excess FBS to detect specific antibodies to tumor cell lysate. A two-fold increase in the titer of IgG specific to tumor cell lysate was observed in 6 patients. Eight of 24 patients made an antibody response to HER-2/neu, four of 24 to MUC1 and one of 24 to p53. Although antibody production to a variety of tumor cell-associated antigens was detected our results suggest that a whole cell vaccine comprising a CD80-transfected allogeneic breast cancer cell line with adjuvant BCG or GM-CSF was not a reliable method to induce significant antibody responses in women with advanced breast cancer.

Preliminary results of active specific immunization with modified tumor cell vaccine in glioblastoma multiforme

OBJECT

Treatment for glioblastoma multiforme has failed to show any progress for decades. While specific immunization with tumor cells modified with Newcastle-Disease-Virus (NDV) has been reported successful in some extracerebral tumors, its effect on glioblastoma is unknown. We report on 11 patients, in whom this approach was analyzed.

METHODS

A vaccine was produced from autologous tumor cell cultures of 11 patients with glioblastoma. After completed surgery and radiotherapy an intracutaneous vaccination was performed 4 times with a 2 week interval and finally after 3 months. Local reactions, general side effects and survival were monitored closely.

RESULTS

The local reaction of the skin after injection of vaccine increased from 1.67 to 4.05 cm2 in 8 weeks. The skin reaction after parallel injection of inactivated, untreated tumor cells increased from 0.11 to 1.09 cm2. The median survival was 46 weeks (mean 60 weeks). No side effects were noted.

CONCLUSION

Active specific immunization with NDV-modified glioblastoma cells produced a noticeable peripheral immune response. In this preliminary series survival of patients was not significantly longer after active specific immunization than after combined treatment of surgery, radiotherapy and chemotherapy. As there were no side effects, however, active specific immunization may be considered an alternative in the management of glioblastoma.

Long-term immunological memory in the resistance of rats to transplanted intracerebral 9L gliosarcoma (9LGS) following subcutaneous immunization with 9LGS cells

Glioblastoma multiforme (GBM) is the most common primary human brain tumor. About 7000 new cases are diagnosed yearly in the USA. Despite current neurosurgical and postoperative radiotherapeutic tumor cytoreduction methods, in most cases occult foci of tumor cells infiltrate surrounding edematous brain tissues and cause recurrent disease within one year. GBM is almost invariably fatal within a few years after it is diagnosed. Our goal is to achieve long-term control of GBM by combining immunoprophylaxis with a radiation-based technique, such as boron neutron-capture therapy (BNCT), potentially capable of specifically targeting the infiltrating tumor cells while sparing the surrounding normal brain tissue. It has long been known that the subcutaneous (sc) injection of irradiated cells or untreated cultured cells (and the removal of the resulting tumors) derived from the well characterized, highly immunogenic 9L gliosarcoma (9LGS) rat model into young isogenic rats can prevent tumor growth after subsequent sc or intracranial (ic) injection of untreated, otherwise lethal 9LGS cells. In this study we have confirmed, quantified and extended those findings to study the efficacy of such immunological memory in normal aging rats and in aging rats previously treated for ic 9LGS tumors by BNCT. (1) The sc injection of 5,000,000 untreated 9LGS cells and the surgical removal of the resulting tumors (method A) protected 80% of normal young rats from an ic challenge with 10,000 untreated 9LGS cells, and a single sc injection of 5,000,000 lethally X-irradiated 9LGS cells (method B) protected 66% of them, but multiple sc injections with a crude particulate fraction prepared from 9LGS cells were not protective. Protection is long-lasting since contralateral ic rechallenge of six-month survivors with an injection of 10,000 viable 9LGS cells resulted in 100% survival. (2) Normal one-year-old rats were only slightly less protected than were normal young rats, approximately 70% rather than approximately 80% (method A) and approximately 60% rather than approximately 66% (method B). (3) BNCT treatment alone resulted in partial immunological protection, as 30% of one-year post-BNCT survivors of ic 9LGS tumors prevailed after contralateral ic rechallenge with 10,000 viable 9LGS cells. Moreover a single sc immunization with 5,000,000 untreated 9LGS cells prior to ic rechallenge boosted survival from 30% to 100%. The relevance of these observations to strategies of preclinical experimentation for immunoprophylaxis of malignant gliomas is discussed.

The combination of boron neutron-capture therapy and immunoprophylaxis for advanced intracerebral gliosarcomas in rats

Glioblastoma multiforme (GBM) is the most common primary human brain tumor. About 7000 new cases are diagnosed yearly in the USA and GBM is almost invariably fatal within a few years after it is diagnosed. Despite current neurosurgical and radiotherapeutic tumor cytoreduction methods, in most cases occult foci of tumor cells infiltrate surrounding brain tissues and cause recurrent disease. Therefore the combination of neurosurgical and radiotherapeutic debulking methods with therapies to inhibit occult GBM cells should improve prognosis. In this study we have combined boron neutron-capture therapy (BNCT), a novel binary radiotherapeutic treatment modality that selectively irradiates tumor tissue and largely spares normal brain tissue, with immunoprophylaxis, a form of active immunization initiated soon after BNCT treatment, to treat advanced, clinically relevantly-sized brain tumors in rats. Using a malignant rat glioma model of high immunogenicity, the 9L gliosarcoma, we have shown that about half of the rats that would have died after receiving BNCT debulking alone, survived after receiving BNCT plus immunoprophylaxis. Further, most of the surviving rats display immunological-based resistance to recurrent 9LGS growth six months or more after treatment. To our knowledge this study represents the first time BNCT and immunoprophylaxis have been combined to treat advanced brain tumors in rats.

Glioma immunology and immunotherapy

OBJECTIVE

Despite advances in conventional therapy, the prognosis for most glioma patients remains dismal. This has prompted an intensive search for effective treatment alternatives. Immunotherapy, one such alternative, has long been recognized as a potentially potent cancer treatment but has been limited by an inadequate understanding of the immune system. Now, increased insight into immunology is suggesting more rational approaches to immunotherapy. In this article, we explore key aspects of modern immunology and discuss their implications for glioma therapy.

METHODS

A thorough literature review of glioma immunology and immunotherapy was undertaken to inquire into the basic immunology, central nervous system immunology, glioma immunobiology, standard glioma immunotherapy, and recent immunotherapeutic advances in glioma treatment.

RESULTS

Although gliomas express tumor-associated antigens and appear potentially sensitive to immune responses, many factors work together to inhibit antiglioma immunity. Not surprisingly, most clinical attempts at glioma immunotherapy have met with little success to date. However, novel immunostimulatory strategies, such as immunogene therapy, directed cytokine delivery, and dendritic cell manipulation, have recently yielded dramatic preclinical results in glioma models. This suggests that glioma-derived immunosuppression can be overcome.

CONCLUSION

Modern molecular biology and immunology techniques have yielded a wealth of new data about glioma immunobiology. Armed with this information, many investigators have proposed novel means to stimulate antiglioma immune responses. Although definitive clinical results remain to be seen, the current renaissance in glioma immunology and immunotherapy shows great promise for the future.

A mouse model of graded contusive spinal cord injury

A mouse model of spinal cord injury (SCI) could further increase our basic understanding of the mechanisms involved in injury and recovery by taking advantage of naturally-occurring and genetically engineered mutations available in mice. We have, therefore, investigated whether methods used to produce and evaluate graded experimental contusive SCI in the rat could be modified to produce a mouse model of traumatic SCI. C57BL6 mice were anesthetized with 2,2,2-tribromoethanol and a restricted laminectomy performed at the T8 vertebral level. The spinal column was stabilized and a weight drop technique used to produce contusive injury. Experimental groups were distinguished by the amount of weight or the height from which the weight was dropped onto an impounder resting on the dura (1 g x 2.5 cm, 2 g x 2.5 cm, 3 g x 2.5 cm, and 3 g x 5.0 cm). Functional deficits over time were examined up to 28 days after SCI by testing hindlimb reflex responses and coordinated motor function. Chronic lesion histopathology was evaluated by light microscopy and analyzed with morphometric techniques. All groups demonstrated profound functional deficits after injury followed by gradual recovery. Recovery correlated with the weight dropped and percent of white matter spared that was 41.3+/-6.0% (mean +/- SEM) in the 2 g x 2.5 cm group and 24.3+/-5.0% in the 3 g x 2.5 cm group. A replicate experiment confirmed reproducibility of the injury. This new mouse model of contusive SCI could pave the way for in vivo studies of the effect of genetic modifications produced by specific mutations on injury and recovery processes after spinal cord trauma.

Production of a bioactive high molecular weight transforming growth factor beta-like molecule by human malignant glioma cell lines

The present study describes identification and partial characterization of a glioma-derived high molecular weight transforming growth factor beta-like molecule (HMW-TGF beta) that requires no activation for biological activity. HMW-TGF beta, constitutively produced by the human glioma cell line, D54MG, is not acid- or heat-labile; is relatively resistant to denaturation, reduction, and high salt treatment. Monoclonal antibody 12A12.D7, produced against partially-purified HMW-TGF beta, was used both to deplete and to neutralize directly a > 158 kDa HMW-TGF beta activity from gel filtration fractions; the antibody also directly neutralized purified mature TGF beta 1. 12A12.D7 recognized a single protein species of 186 kDa from unlabeled glioma cell conditioned media and 35S-labeled lysates. HMW-TGF beta is not due to complex formation between TGF beta and any of the known carrier molecules. Production of HMW-TGF beta by glioma cells could facilitate tumor cell proliferation, and thus contribute to the inexorable and rapid progression that characterizes malignant gliomas.

Relationship between immune response to melanoma vaccine immunization and clinical outcome in stage II malignant melanoma

The authors investigated whether there was a relationship between the induction of a delayed-type hypersensitivity (DTH) response to melanoma vaccine immunization and disease recurrence. They studied prospectively 94 evaluable patients with surgically resected Stage II malignant melanoma who were immunized to a partially purified, polyvalent, melanoma antigen vaccine. The DTH response to skin tests to the vaccine was measured before treatment and at the fourth vaccine immunization. Vaccine treatment induced a strong DTH response in 29 (31%) patients, an intermediate response in 24 (25%), and no response in 41 (44%). The median disease-free survival (DFS) of patients with a strong, intermediate, and no DTH response to vaccine immunization was more than 72 months, 24 months, and 15 months, respectively. The relationship between an increase in the DTH response and a prolonged DFS was statistically significant (P = 0.02); clinically meaningful (the median DFS of patients with a strong DTH response was 4.7 years longer than that of nonresponders); and, by multivariate analysis, independent of disease severity or overall immune competence. These findings suggest, but do not prove, that vaccine treatment can slow the progression of melanoma in some patients.

Tumor vaccines

Melanoma vaccines are an exciting and increasingly attractive immunotherapeutic approach for malignant melanoma. Vaccines can be used for patients with high risk primary melanoma and regional disease, stages in the progression of melanoma for which there is presently no treatment. They are unique in their potential to prevent cancer in high risk individuals. Multiple approaches are being followed to develop effective vaccines. It is too early to judge whether any of them effectively slow the progression of melanoma. However, it is clear that vaccines are safe to use, and that they can stimulate immune responses to melanoma in some patients. The specificity of these responses needs to be clarified, and multiple challenges remain to be overcome before effective vaccines to melanoma become available. We must first identify the antigens on melanoma that stimulate immune responses, define the immune effector mechanisms that are stimulated by vaccine immunization and identify those responsible for increasing resistance to tumor growth, devise appropriate ways of constructing vaccines that will induce such responses, and find adjuvants and/or immunodulators that will potentiate desirable immune responses.

Immunology of central nervous system tumors

With progress in cellular immunology and the development of hybridoma technology, the idea of manipulating host-tumor immune interactions to improve the prognosis of brain tumors has aroused renewed interest. Although no brain tumor-specific antigens have been found, and in spite of the wide antigenic heterogeneity of brain tumor cells, some monoclonal antibodies possessing restricted specificity have been isolated and their potential clinical applications investigated. One of the most pronounced changes in the cellular immune responses of brain tumor patients is a profound depression of the T4-helper lymphocytes. Clinical and laboratory trials are under way to assess the ability of lymphokines, such as gamma-interferon or interleukin-2, to restore immunologic competence in these patients and potentiate a specific anti-tumor immunologic response. Recent work suggests that the endothelium-astrocyte complex may have a pivotal role in assisting the escape of brain tumors from the host's immunologic responses, since it is responsible for the intracerebral sequestration of antigens and local anti-tumor responses. In this review, the data on the antigenic properties of central nervous system tumors and the host's humoral and cellular immune responses to them are analyzed and potential immunologic therapies are discussed.

Immunophenotypic differences between normal glia, astrocytomas and malignant gliomas: correlations with karyotype, natural history and survival

The karyotypic and antigenic phenotypes of early passage normal and malignant glial cultures were correlated in vitro. Astrocytomas (4) were distinguished from the normal glia (8) by a mixed near-diploid karyotype and anchorage-independent growth. Malignant gliomas (41) demonstrated cytogenetic abnormalities ranging from mixed normal G- and Q-banded and near-diploid cultures, through mixed near-diploid/hyperdiploid to predominantly hyperdiploid stem-lines. This correlated with the differential expression of certain antigens and established qualitative antigenic differences from normal glia. Associations were found between histopathologic grade of glial neoplasm and the expression of antigens 5.1H11 (p = 0.0002), CNT/11 (p = 0.001), CNT/10 (p = 0.004), CAT301 (p = 0.014), M111 (p = 0.024), and L101 (p = 0.044). An ominous association was demonstrated between the duration of clinical survival and the expression of antigens 5.1H11 (p = 0.0007), CNT/10 (p = 0.027) and B2.6 (p = 0.038). Correcting for diagnosis and age, multivariate analysis demonstrated that HLA-DR (p = 0.050) and 5.1H11 (p = 0.069) were unfavorably correlated with patient survival. This suggests the application of the in vitro immunophenotype for its predictive utility, as well as a novel method of selection of tumor-associated antigens for monoclonal antibody-mediated immunotherapy.

Immunobiology of primary intracranial tumors. Part 7: Active immunization of patients with anaplastic human glioma cells: a pilot study

Twenty patients with malignant gliomas were selected for active immunization within 4 weeks following surgery. Each patient had a Karnofsky Functional Rating equal to or greater than 70, a peripheral blood lymphocyte count equal to or greater than 1000 cells/cu mm, skin test responses to one or more of four recall antigens, peripheral blood T-cells equal to or greater than half that of control, and was not receiving steroid therapy at the time of entry into the study. Each patient received subcutaneous inoculations with one of two human glioma tissue culture cell lines (D-54MG or U-251MG) monthly, with 500 micrograms of bacillus Calmette-Guérin cell wall (BCG-CW) being included with the first inoculation. Each patient also received levamisole, 2.5 mg/kg 3 days per week every other week. Radiotherapy and chemotherapy with BCNU were begun after the first month of immunization. Follow-up evaluations included computerized tomography brain scans, neurological examinations, Karnofsky Functional Ratings, and studies of general immune competence. No evidence of allergic encephalomyelitis was noted clinically, nor was any gross or microscopic evidence of such pathology obtained upon autopsy of three of these patients. Serial studies of general immune competence showed no alterations from those previously described with non-immunized patients. Patients who were inoculated with the U-251MG cell line have had a longer survival time compared to those inoculated with the D-54MG cell line (p less than 0.0590) or compared to 58 historical cases of glioma patients treated with levamisole, radiation therapy, and chemotherapy alone (p less than 0.02).