T-cell immunotherapy for malignant glioma: toward a combined approach

Anti-Gene IGF-I Vaccines in Cancer Gene Therapy: A Review of a Case of Glioblastoma

OBJECTIVE

Vaccines for the deadliest brain tumor - glioblastoma (GBM) - are generally based on targeting growth factors or their receptors, often using antibodies. The vaccines described in the review were prepared to suppress the principal cancer growth factor - IGF-I, using anti-gene approaches either of antisense (AS) or of triple helix (TH) type. Our objective was to increase the median survival of patients treated with AS and TH cell vaccines.

METHODOLOGY

The cells were transfected in vitro by both constructed IGF-I AS and IGF-I TH expression episomal vectors; part of these cells was co-cultured with plant phytochemicals, modulating IGF-I expression. Both AS and TH approaches completely suppressed IGF-I expression and induced MHC-1 / B7 immunogenicity related to the IGF-I receptor signal.

RESULTS

This immunogenicity proved to be stronger in IGF-I TH than in IGF-I AS-prepared cell vaccines, especially in TH / phytochemical cells. The AS and TH vaccines generated an important TCD8+ and TCD8+CD11b- immune response in treated GBM patients and increased the median survival of patients up to 17-18 months, particularly using TH vaccines; in some cases, 2- and 3-year survival was reported. These clinical results were compared with those obtained in therapies targeting other growth factors.

CONCLUSION

The anti-gene IGF-I vaccines continue to be applied in current GBM personalized medicine. Technical improvements in the preparation of AS and TH vaccines to increase MHC-1 and B7 immunogenicity have, in parallel, allowed to increase in the median survival of patients.

Efficacy of cell-based immunotherapies on patients with glioma: an umbrella review of systematic reviews and meta-analysis protocol

INTRODUCTION

Glial brain tumours are highly mortal and are noted as major neurosurgical challenges due to frequent recurrence or progression. Despite standard-of-care treatment for gliomas, the prognosis of patients with higher-grade glial tumours is still poor, and hence empowering antitumour immunity against glioma is a potential future oncological prospect. This review is designed to improve our understanding of the efficacy of cell-based immunotherapies for glioma.

METHODS AND ANALYSIS

This systematic review will be performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive search of main electronic databases: PubMed/MEDLINE, Scopus, ISI Web of Science EMBASE and ProQuest will be done on original articles, followed by a manual review of review articles. Only records in English and only clinical trials will be encountered for full-text review. All the appropriate studies that encountered the inclusion criteria will be screened, selected and then will undergo data extraction step by two independent authors. For meta-analyses, data heterogeneity for each parameter will be first evaluated by Cochran's Q and I2 statistics. In case of possible heterogeneity, a random-effects meta-analysis will be performed and for homogenous data, fixed-effects models will be selected for reporting the results of the proportional meta-analysis. Bias risk will be assessed through Begg's and Egger's tests and will also be visualised by Funnel plots.

ETHICS AND DISSEMINATION

As this study will be a systematic review without human participants' involvement, no ethical registration is required and meta-analysis will be presented at a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022373297.

Dynamic interplay between corticosteroid treatment and the role of SRC-1 gene dysregulation in the progression of WHO-Grade 4 Astrocytoma

BACKGROUND

Corticosteroid is commonly used before surgery to control cerebral oedema in brain tumours and is frequently continued throughout treatment. Its long-term effect of on the recurrence of WHO-Grade 4 astrocytoma remains controversial. The interaction between corticosteroid, SRC-1 gene and cytotoxic T-cells has never been investigated.

METHODS

A retrospective cohort of 36 patients with WHO-Grade 4 astrocytoma were examined for CD8 + T-cell and SRC-1 gene expressions through IHC and qRT-PCR. The impact of corticosteroid on CD8+T-cells infiltration, SRC-1 expression, and tumour recurrence was analyzed.

RESULTS

The mean patients age was 47-years, with a male to female ratio 1.2. About 78% [n = 28] of the cases showed reduced or no CD8+T-cell expression while 22% [n = 8] of cases have showed medium to high CD8+T-cell expression. SRC-1 gene was upregulated in 5 cases [14%] and 31 cases [86%] showed SRC-1 downregulation. The average of total days and doses of administered corticosteroid from the preoperative period to the postoperative period was at range of 14-106 days and 41-5028 mg, respectively. There was no significant statistical difference in RFI among tumours expressing high or low CD8+T-cells when corticosteroid was administered in recommended or exceeded doses [p-value = 0.640]. There was a significant statistical difference in RFI between CD8+T-Cell expression and SRC-1 gene dysregulation [p-value = 002]. Tumours with high CD8+T T-cell expression and SRC-1 gene downregulation had late recurrence.

CONCLUSIONS

Corticosteroid treatment can directly affect the SRC-1 gene regulation but does not directly influence cytotoxic T-cells infiltration or tumor progression. However, SRC-1 gene downregulation can facilitate late tumor recurrence.

Identification of an endoplasmic reticulum stress-related signature associated with clinical prognosis and immune therapy in glioma

Background

Glioma is the most common brain tumor in adults and is characterized by a short survival time and high resistance to chemotherapy. It is imperative to determine the prognosis and therapy-related targets for glioma. Endoplasmic reticulum stress (ERS), as an adaptive protective mechanism, indicates the unfolded protein response (UPR) to determine cell survival and affects chemotherapy sensitivity, which is related to the prognosis of glioma.

Methods

Our research used the TCGA database as the training group and the CGGA database as the testing group. Lasso regression and Cox analysis were performed to construct an ERS signature-based risk score model in glioma. Three methods (time-dependent receiver operating characteristic analysis and multivariate and univariate Cox regression analysis) were applied to assess the independent prognostic effect of texture parameters. Consensus clustering was used to classify the two clusters. In addition, functional and immune analyses were performed to assess the malignant process and immune microenvironment. Immunotherapy and anticancer drug response prediction were adopted to evaluate immune checkpoint and chemotherapy sensitivity.

Results

The results revealed that the 7-gene signature strongly predicts glioma prognosis. The two clusters have markedly distinct molecular and prognostic features. The validation group result revealed that the signature has exceptional repeatability and certainty. Functional analysis showed that the ERS-related gene signature was closely associated with the malignant process and prognosis of tumors. Immune analysis indicated that the ERS-related gene signature is strongly related to immune infiltration. Immunotherapy and anticancer drug response prediction indicated that the ERS-related gene signature is positively correlated with immune checkpoint and chemotherapy sensitivity.

Conclusions

Collectively, the ERS-related risk model can provide a novel signature to predict glioma prognosis and treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02709-y.

Interaction of germline variants in a family with a history of early-onset clear cell renal cell carcinoma

Background

Identification of genetic factors causing predisposition to renal cell carcinoma has helped improve screening, early detection, and patient survival.

Methods

We report the characterization of a proband with renal and thyroid cancers and a family history of renal and other cancers by whole‐exome sequencing (WES), coupled with WES analysis of germline DNA from additional affected and unaffected family members.

Results

This work identified multiple predicted protein‐damaging variants relevant to the pattern of inherited cancer risk. Among these, the proband and an affected brother each had a heterozygous Ala45Thr variant in SDHA, a component of the succinate dehydrogenase (SDH) complex. SDH defects are associated with mitochondrial disorders and risk for various cancers; immunochemical analysis indicated loss of SDHB protein expression in the patient’s tumor, compatible with SDH deficiency. Integrated analysis of public databases and structural predictions indicated that the two affected individuals also had additional variants in genes including TGFB2, TRAP1, PARP1, and EGF, each potentially relevant to cancer risk alone or in conjunction with the SDHA variant. In addition, allelic imbalances of PARP1 and TGFB2 were detected in the tumor of the proband.

Conclusion

Together, these data suggest the possibility of risk associated with interaction of two or more variants.

Microenvironmental clues for glioma immunotherapy

Gliomas have been viewed for decades as inaccessible for a meaningful antitumor immune response as they grow in a sanctuary site protected from infiltrating immune cells. Moreover, the glioma microenvironment constitutes a hostile environment for an efficient antitumor immune response as glioma-derived factors such as transforming growth factor β and catabolites of the essential amino acid tryptophan paralyze T-cell function. There is growing evidence from preclinical and clinical studies that a meaningful antitumor immunity exists in glioma patients and that it can be activated by vaccination strategies. As a consequence, the concept of glioma immunotherapy appears to be experiencing a renaissance with the first phase 3 randomized immunotherapy trials entering the clinical arena. On the basis of encouraging results from other tumor entities using immunostimulatory approaches by blocking endogenous T-cell suppressive pathways mediated by cytotoxic T-lymphocyte antigen 4 or programmed cell death protein 1/programmed cell death protein 1 ligand 1 with humanized antibodies, there is now a realistic and promising option to combine active immunotherapy with agents blocking the immunosuppressive microenvironment in patients with gliomas to allow a peripheral antitumor immune response induced by vaccination to become effective. Here we review the current clinical and preclinical evidence of antimicroenvironment immunotherapeutic strategies in gliomas.

Blockade of mTOR signaling via rapamycin combined with immunotherapy augments antiglioma cytotoxic and memory T-cell functions

The success of immunotherapeutic approaches targeting glioblastoma multiforme (GBM) demands a robust antiglioma T-cell cytotoxic and memory response. Recent evidence suggests that rapamycin regulates T-cell differentiation. Herein, we tested whether administration of rapamycin could enhance the efficacy of immunotherapy utilizing Fms-like tyrosine kinase 3 ligand (Ad-Flt3L) and thymidine kinase/ganciclovir (Ad-TK/GCV). Using the refractory rat RG2 glioma model, we demonstrate that administration of rapamycin with Ad-Flt3L + Ad-TK/GCV immunotherapy enhanced the cytotoxic activity of antitumor CD8(+) T cells. Rats treated with rapamycin + Ad-Flt3L + Ad-TK/GCV exhibited massive reduction in the tumor volume and extended survival. Rapamycin administration also prolonged the survival of Ad-Flt3L + Ad-TK/GCV-treated GL26 tumor-bearing mice, associated with an increase in the frequency of tumor-specific and IFNγ(+) CD8(+) T cells. More importantly, rapamycin administration, even for a short interval, elicited a potent long-lasting central memory CD8(+) T-cell response. The enhanced memory response translated to an increased frequency of tumor-specific CD8(+) T cells within the tumor and IFNγ release, providing the mice with long-term survival advantage in response to tumor rechallenge. Our data, therefore, point to rapamycin as an attractive adjuvant to be used in combination with immunotherapy in a phase I clinical trial for GBM.

A new hope in immunotherapy for malignant gliomas: adoptive T cell transfer therapy

Immunotherapy emerged as a promising therapeutic approach to highly incurable malignant gliomas due to tumor-specific cytotoxicity, minimal side effect, and a durable antitumor effect by memory T cells. But, antitumor activities of endogenously activated T cells induced by immunotherapy such as vaccination are not sufficient to control tumors because tumor-specific antigens may be self-antigens and tumors have immune evasion mechanisms to avoid immune surveillance system of host. Although recent clinical results from vaccine strategy for malignant gliomas are encouraging, these trials have some limitations, particularly their failure to expand tumor antigen-specific T cells reproducibly and effectively. An alternative strategy to overcome these limitations is adoptive T cell transfer therapy, in which tumor-specific T cells are expanded ex vivo rapidly and then transferred to patients. Moreover, enhanced biologic functions of T cells generated by genetic engineering and modified immunosuppressive microenvironment of host by homeostatic T cell expansion and/or elimination of immunosuppressive cells and molecules can induce more potent antitumor T cell responses and make this strategy hold promise in promoting a patient response for malignant glioma treatment. Here we will review the past and current progresses and discuss a new hope in adoptive T cell therapy for malignant gliomas.

Synergy between CD8 T cells and Th1 or Th2 polarised CD4 T cells for adoptive immunotherapy of brain tumours

The feasibility of cancer immunotherapy mediated by T lymphocytes is now a clinical reality. Indeed, many tumour associated antigens have been identified for cytotoxic CD8 T cells, which are believed to be key mediators of tumour rejection. However, for aggressive malignancies in specialised anatomic sites such as the brain, a limiting factor is suboptimal tumour infiltration by CD8 T cells. Here we take advantage of recent advances in T cell biology to differentially polarise CD4 T cells in order to explore their capacity to enhance immunotherapy. We used an adoptive cell therapy approach to work with clonal T cell populations of defined specificity. Th1 CD4 T cells preferentially homed to and accumulated within intracranial tumours compared with Th2 CD4 T cells. Moreover, tumour-antigen specific Th1 CD4 T cells enhanced CD8 T cell recruitment and function within the brain tumour bed. Survival of mice bearing intracranial tumours was significantly prolonged when CD4 and CD8 T cells were co-transferred. These results should encourage further definition of tumour antigens recognised by CD4 T cells, and exploitation of both CD4 and CD8 T cell subsets to optimise T cell therapy of cancer.

Reciprocal complementation of the tumoricidal effects of radiation and natural killer cells

The tumor microenvironment is a key determinant for radio-responsiveness. Immune cells play an important role in shaping tumor microenvironments; however, there is limited understanding of how natural killer (NK) cells can enhance radiation effects. This study aimed to assess the mechanism of reciprocal complementation of radiation and NK cells on tumor killing. Various tumor cell lines were co-cultured with human primary NK cells or NK cell line (NK-92) for short periods and then exposed to irradiation. Cell proliferation, apoptosis and transwell assays were performed to assess apoptotic efficacy and cell viability. Western blot analysis and immunoprecipitation methods were used to determine XIAP (X-linked inhibitor of apoptosis protein) and Smac (second mitochondria-derived activator of caspase) expression and interaction in tumor cells. Co-culture did not induce apoptosis in tumor cells, but a time- and dose-dependent enhancing effect was found when co-cultured cells were irradiated. A key role for caspase activation via perforin/granzyme B (Grz B) after cell-cell contact was determined, as the primary radiation enhancing effect. The efficacy of NK cell killing was attenuated by upregulation of XIAP to bind caspase-3 in tumor cells to escape apoptosis. Knockdown of XIAP effectively potentiated NK cell-mediated apoptosis. Radiation induced Smac released from mitochondria and neutralized XIAP and therefore increased the NK killing. Our findings suggest NK cells in tumor microenvironment have direct radiosensitization effect through Grz B injection while radiation enhances NK cytotoxicity through triggering Smac release.

Brain tumor immunotherapy: seeing the brain in the body

Brain tumor immunotherapy is often interpreted in terms of immune privilege and the blood-brain barrier (BBB), but a broader view is warranted. The delicate regulatory balance of the immune system is relevant at any site, as are the heterogeneity and plasticity of tumor growth. Criteria for tumor antigens, and often the antigens themselves, cut across tumor types. Here, this broader view, complemented by current understanding of privilege and the BBB, provides the context for review. Future success is likely to exploit simplified methods, used in combination; and similarities - more than differences - between the brain and other sites.

Gene therapy-mediated reprogramming tumor infiltrating T cells using IL-2 and inhibiting NF-κB signaling improves the efficacy of immunotherapy in a brain cancer model

Immune-mediated gene therapy using adenovirus expressing Flt3 ligand and thymidine kinase followed by ganciclovir administration (Flt3/TK) effectively elicits tumor regression in preclinical glioma models. Herein, we assessed new strategies to optimize Flt3L/TK therapeutic efficacy in a refractory RG2 orthotopic glioblastoma model. Specifically, we aimed to optimize the therapeutic efficacy of Flt3L/TK treatment in the RG2 model by overexpressing the following genes within the brain tumor microenvironment: 1) a TK mutant with enhanced cytotoxicity (SR39 mutant TK), 2) Flt3L-IgG fusion protein that has a longer half-life, 3) CD40L to stimulate DC maturation, 4) T helper cell type 1 polarizing dendritic cell cytokines interleukin-12 or C-X-C motif ligand 10 chemokine (CXCL)-10, 5) C-C motif ligand 2 chemokine (CCL2) or C-C motif ligand 3 chemokine (CCL3) to enhance dendritic cell recruitment into the tumor microenvironment, 6) T helper cell type 1 cytokines interferon-γ or interleukin-2 to enhance effector T-cell functions, and 7) IκBα or p65RHD (nuclear factor kappa-B [NF-κB] inhibitors) to suppress the function of Foxp3+ Tregs and enhanced effector T-cell functions. Anti-tumor immunity and tumor specific effector T-cell functions were assessed by cytotoxic T lymphocyte assay and intracellular IFN-γ staining. Our data showed that overexpression of interferon-γ or interleukin-2, or inhibition of the nuclear factor kappa-B within the tumor microenvironment, enhanced cytotoxic T lymphocyte-mediated immune responses and successfully extended the median survival of rats bearing intracranial RG2 when combined with Flt3L/TK. These findings indicate that enhancement of T-cell functions constitutes a critical therapeutic target to overcome immune evasion and enhance therapeutic efficacy for brain cancer. In addition, our study provides novel targets to be used in combination with immune-therapeutic strategies for glioblastoma, which are currently being tested in the clinic.

HLA-E contributes to an immune-inhibitory phenotype of glioblastoma stem-like cells

Cancer stem cells are an attractive target for immunotherapeutic approaches to glioblastoma. However, an immune inhibitory phenotype of cells currently classified as "glioma-initiating cells" (GIC) might counteract recognition by immune effector cells. Here, we investigate the contribution of the non-classical MHC molecule HLA-E to the immunosuppressive phenotype of GIC. HLA-E is expressed in GIC lines and its expression is reduced upon differentiation of GIC in serum-containing culture conditions. Constitutive HLA-E inhibits natural killer (NK) cell-mediated lysis of GIC since small-interfering RNA-mediated HLA-E gene silencing enhances the immunogenicity of GIC. Increased GIC lysis was observed both in the CD133+ and in the CD133- compartment. Furthermore, the use of interferon-γ as a possible agent to boost an immune response against glioblastoma cells might be limited by the concurrent upregulation of HLA-E.