Identification of candidate neoantigens produced by fusion transcripts in human osteosarcomas.

Osteosarcomas are characterized by highly disrupted genomes. Although osteosarcomas lack common fusions, we find evidence of many tumour specific gene-gene fusion transcripts, likely due to chromosomal rearrangements and expression of transcription-induced chimeras. Most of the fusions result in out-of-frame transcripts, potentially capable of producing long novel protein sequences and a plethora of neoantigens.

Biphasic Dependence of Glioma Survival and Cell Migration on CD44 Expression Level.

While several studies link the cell-surface marker CD44 to cancer progression, conflicting results show both positive and negative correlations with increased CD44 levels. Here, we demonstrate that the survival outcomes of genetically induced glioma-bearing mice and of high-grade human glioma patients are biphasically correlated with CD44 level, with the poorest outcomes occurring at intermediate levels. Furthermore, the high-CD44-expressing mesenchymal subtype exhibited a positive trend of survival with increased CD44 level.

Monomeric annexin A2 is an oxygen-regulated toll-like receptor 2 ligand and adjuvant.

Background: Annexin A2 (ANXA2) is a pleiotropic, calcium-dependent, phospholipid-binding protein with a broad tissue distribution. It can be intracellular, membrane-bound, or secreted, and it exists as a monomer or heterotetramer. The secreted ANXA2 heterotetramer signals human and murine macrophages to produce IL-1, IL-6, and TNF-α through TLR4/MyD88- and TRIF-dependent pathways.

Parthenolide prodrug LC-1 slows growth of intracranial glioma.

LC-1 (also known as DMAPT or dimethylamino-parthenolide), a prodrug of parthenolide, was tested for anti-proliferative activity against glioma. LC-1 was found to have low micromolar cytotoxic activity against three glioma cell lines and was also found to be brain penetrant in healthy mice (2.1-3.

Decreased affinity for efflux transporters increases brain penetrance and molecular targeting of a PI3K/mTOR inhibitor in a mouse model of glioblastoma.

Background: Targeting drug delivery to invasive glioma cells is a particularly difficult challenge because these cells lie behind an intact blood-brain barrier (BBB) that can be observed using multimodality imaging. BBB-associated efflux transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) influence drug distribution to these cells and may negatively impact efficacy. To test the hypothesis that efflux transporters influence brain pharmacokinetics/pharmacodynamics of molecularly targeted agents in glioma treatment, we assessed region-specific penetrance and molecular-targeting capacity for a PI3K/mTOR kinase inhibitor that has high substrate affinity for efflux transporters (GDC-0980) and an analog (GNE-317) that was purposely designed to have reduced efflux.

Effective Treatment of Established GL261 Murine Gliomas through Picornavirus Vaccination-Enhanced Tumor Antigen-Specific CD8+ T Cell Responses.

Glioblastoma (GBM) is among the most invasive and lethal of cancers, frequently infiltrating surrounding healthy tissue and giving rise to rapid recurrence. It is therefore critical to establish experimental model systems and develop therapeutic approaches that enhance anti-tumor immunity. In the current study, we have employed a newly developed murine glioma model to assess the efficacy of a novel picornavirus vaccination approach for the treatment of established tumors.

Vaccination with dendritic cells loaded with allogeneic brain tumor cells for recurrent malignant brain tumors induces a CD4(+)IL17(+) response.

Background: We tested the hypothesis that a novel vaccine developed from autologous dendritic cells (DC) loaded with cells from a unique allogeneic brain tumor cell line (GBM6-AD) would be well-tolerated and would generate an immune response.

Method: Patients with recurrent primary brain tumors underwent vaccination with GBM6-AD/DC vaccine. Subjects were treated at escalating DC cell doses: 5 × 10(6) (one patient), 10 × 10(6) (one patient) and 15 × 10(6) (6 patients).

Structure-activity relationship analysis of imidazoquinolines with Toll-like receptors 7 and 8 selectivity and enhanced cytokine induction.

Toll-like receptors 7 and 8 (TLRs) have emerged as key targets in the design of small molecule adjuvants and stimulants for use in immunotherapies. This study examines the structure-activity relationship of a series of C2- and N1-substituted C7-methoxycarbonylimidazoquinolines to gain insight to the structural basis to TLR-7 and -8 selective activity. The analysis is further applied to evaluate the induction of multiple cytokines, including IL-10, IL-12, IL-1β, TNF-α, IFN-α, and IFN-γ, using murine BMDCs and human PBMCs.

CD8+ T cell-independent tumor regression induced by Fc-OX40L and therapeutic vaccination in a mouse model of glioma.

Despite the growing number of preclinical and clinical trials focused on immunotherapy for the treatment of malignant gliomas, the prognosis for this disease remains grim. Although some promising advances have been made, the immune response stimulated as a result of immunotherapeutic protocols has been inefficient at complete tumor elimination, primarily due to our lack of understanding of the necessary effector functions of the immune system. We previously demonstrated that a tumor lysate vaccine/Fc-OX40L therapy is capable of inducing enhanced survival and tumor elimination in the GL261 mouse glioma model.

Immunogenicity of murine solid tumor models as a defining feature of in vivo behavior and response to immunotherapy.

Immune profiling has been widely used to probe mechanisms of immune escape in cancer and identify novel targets for therapy. Two emerging uses of immune signatures are to identify likely responders to immunotherapy regimens among individuals with cancer and to understand the variable responses seen among subjects with cancer in immunotherapy trials. Here, the immune profiles of 6 murine solid tumor models (CT26, 4T1, MAD109, RENCA, LLC, and B16) were correlated to tumor regression and survival in response to 2 immunotherapy regimens.

GM-CSF promotes the immunosuppressive activity of glioma-infiltrating myeloid cells through interleukin-4 receptor-α.

Malignant gliomas are lethal cancers in the brain and heavily infiltrated by myeloid cells. Interleukin-4 receptor-α (IL-4Rα) mediates the immunosuppressive functions of myeloid cells, and polymorphisms in the IL-4Rα gene are associated with altered glioma risk and prognosis. In this study, we sought to evaluate a hypothesized causal role for IL-4Rα and myeloid suppressor cells in glioma development.

CD133-targeted paclitaxel delivery inhibits local tumor recurrence in a mouse model of breast cancer.

Expression of the membrane protein CD133 marks a subset of cancer cells with drug resistant phenotype and enhanced tumor initiating ability in xenotransplantation assays. Because drug resistance and tumor relapse are significant problems, approaches to eliminate these cells are urgently needed. As a step towards achieving this goal, we developed polymeric nanoparticles targeting CD133 by conjugating an anti-CD133 monoclonal antibody to nanoparticles formulated using poly(D,L lactide-co-glycolide) polymer.

MMuFLR: missense mutation and frameshift location reporter.

Motivation: Cancer researchers seeking immunotherapy targets in cancer cells need tools to locate highly expressed proteins unique to cancer cells. Missense mutation and frameshift location reporter (MMuFLR), a Galaxy-based workflow, analyzes next-generation sequencing paired read RNA-seq output to reliably identify small frameshift mutations and missense mutations in highly expressed protein-coding genes. MMuFLR ignores known SNPs, low quality reads and poly-A/T sequences.

Minicircle DNA is superior to plasmid DNA in eliciting antigen-specific CD8+ T-cell responses.

Clinical trials reveal that plasmid DNA (pDNA)-based gene delivery must be improved to realize its potential to treat human disease. Current pDNA platforms suffer from brief transgene expression, primarily due to the spread of transcriptionally repressive chromatin initially deposited on plasmid bacterial backbone sequences. Minicircle (MC) DNA lacks plasmid backbone sequences and correspondingly confers higher levels of sustained transgene expression upon delivery, accounting for its success in preclinical gene therapy models.

Profound impairment of adaptive immune responses by alkylating chemotherapy.

Overall, cancer vaccines have had a record of failure as an adjuvant therapy for malignancies that are treated with alkylating chemotherapy, and the contribution of standard treatment to that failure remains unclear. Vaccines aim to harness the proliferative potential of the immune system by expanding a small number of tumor-specific lymphocytes into a large number of antitumor effectors. Clinical trials are often conducted after treatment with alkylating chemotherapy, given either as standard therapy or for immunomodulatory effect.

Immunotoxin targeting CD133(+) breast carcinoma cells.

CD133 expression enriches for tumor-initiating cells and is a negative prognostic factor in numerous cancers. We previously developed an immunotoxin against CD133 by fusing a gene fragment encoding the scFv portion of an anti-CD133 antibody to a gene fragment encoding deimmunized PE38KDEL. The resulting fusion protein, dCD133KDEL, demonstrated potent antitumor activity following intratumoral delivery into head neck cell carcinoma xenografts.

Identification and characterization of a novel scFv recognizing human and mouse CD133.

CD133, also known as Prominin-1, is expressed on stem cells present in many tissues and tumors. In this work, we have identified and characterized a single-chain variable fragment (scFv) for the efficient and specific recognition of CD133. Phage display was used to develop the scFv from a previously reported anti-CD133 hybridoma clone 7, which was capable of recognizing both glycosylated and non-glycosylated forms of human CD133.

Vaccination for invasive canine meningioma induces in situ production of antibodies capable of antibody-dependent cell-mediated cytotoxicity.

Malignant and atypical meningiomas are resistant to standard therapies and associated with poor prognosis. Despite progress in the treatment of other tumors with therapeutic vaccines, this approach has not been tested preclinically or clinically in these tumors. Spontaneous canine meningioma is a clinically meaningful but underutilized model for preclinical testing of novel strategies for aggressive human meningioma.

Vaccine injection site matters: qualitative and quantitative defects in CD8 T cells primed as a function of proximity to the tumor in a murine glioma model.

Malignant gliomas are lethal brain tumors for which novel therapies are urgently needed. In animal models, vaccination with tumor-associated Ags efficiently primes T cells to clear gliomas. In clinical trials, cancer vaccines have been less effective at priming T cells and extending survival.

Immunologic privilege in the central nervous system and the blood-brain barrier.

The brain is in many ways an immunologically and pharmacologically privileged site. The blood-brain barrier (BBB) of the cerebrovascular endothelium and its participation in the complex structure of the neurovascular unit (NVU) restrict access of immune cells and immune mediators to the central nervous system (CNS). In pathologic conditions, very well-organized immunologic responses can develop within the CNS, raising important questions about the real nature and the intrinsic and extrinsic regulation of this immune privilege.

Function of the blood-brain barrier and restriction of drug delivery to invasive glioma cells: findings in an orthotopic rat xenograft model of glioma.

Despite aggressive treatment with radiation and chemotherapy, recurrence of glioblastoma multiforme (GBM) is inevitable. The objective of this study was to show that the blood-brain barrier (BBB), through a combination of tight junctions and active efflux transporters in the brain microvasculature, can significantly restrict delivery of molecularly targeted agents to invasive glioma cells. Transgenic mice lacking P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp) were used to study efflux of erlotinib at the BBB.

Active efflux of Dasatinib from the brain limits efficacy against murine glioblastoma: broad implications for the clinical use of molecularly targeted agents.

The importance of the blood-brain barrier in preventing effective pharmacotherapy of glioblastoma has been controversial. The controversy stems from the fact that vascular endothelial cell tight junctions are disrupted in the tumor, allowing some systemic drug delivery. P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP) efflux drugs from brain capillary endothelial cells into the blood.

Discovery of Imidazoquinolines with Toll-Like Receptor 7/8 Independent Cytokine Induction.

Toll-like receptors (TLRs) are key targets in the design of immunomodulating agents for use as vaccine adjuvants and anticancer treatments. The imidazoquinolines, imiquimod and resiquimod, have been shown to activate TLR-7 and -8 which in turn induce cytokine production as part of the innate immune response. Herein, we report the synthesis and discovery of a C7-methoxycarbonyl derivative of imiquimod that stimulates cytokine production but is devoid of TLR-7/8 activity.

Increasing the efficacy of tumor cell vaccines by enhancing cross priming.

Cancer immunotherapy has been attempted for more than a century, and investment has intensified in the last 20 years. The complexity of the immune system is exemplified by the myriad of immunotherapeutic approaches under investigation. While anti-tumor immunity has been achieved experimentally with multiple effector cells and molecules, particular promise is shown for harnessing the CD8 T cell response.