The TNF receptor family member Fn14 is highly expressed in recurrent glioblastoma and in GBM patient-derived xenografts with acquired temozolomide resistance

Background

Glioblastoma (GBM) is a difficult to treat brain cancer that nearly uniformly recurs, and recurrent tumors are largely therapy resistant. Our prior work has demonstrated an important role for the tumor necrosis factor-like weak inducer of apoptosis (TWEAK) receptor fibroblast growth factor-inducible 14 (Fn14) in GBM pathobiology. In this study, we investigated Fn14 expression in recurrent GBM and in the setting of temozolomide (TMZ) resistance.

Methods

Fn14 mRNA expression levels in nonneoplastic brain, primary (newly diagnosed) GBM, and recurrent GBM (post-chemotherapy and radiation) specimens were obtained from The Cancer Genome Atlas data portal. Immunohistochemistry was performed using nonneoplastic brain, patient-matched primary and recurrent GBM, and gliosarcoma (GSM) specimens to examine Fn14 protein levels. Western blot analysis was used to compare Fn14 expression in parental TMZ-sensitive or matched TMZ-resistant patient-derived xenografts (PDXs) established from primary or recurrent tumor samples. The migratory capacity of control and Fn14-depleted TMZ-resistant GBM cells was assessed using the transwell migration assay.

Results

We found that Fn14 is more highly expressed in recurrent GBM tumors than their matched primary GBM counterparts. Fn14 expression is also significantly elevated in GSM tumors. GBM PDX cells with acquired TMZ resistance have higher Fn14 levels and greater migratory capacity than their corresponding parental TMZ-sensitive cells, and the migratory difference is due, at least in part, to Fn14 expression in the TMZ-resistant cells.

Conclusions

This study demonstrates that the Fn14 gene is highly expressed in recurrent GBM, GSM, and TMZ-resistant GBM PDX tumors. These findings suggest that Fn14 may be a valuable therapeutic target or drug delivery portal for treatment of recurrent GBM and GSM patients.

Antibody-drug conjugates in glioblastoma therapy: the right drugs to the right cells

Glioblastomas are high-grade brain tumours with a poor prognosis and, currently, few available therapeutic options. This lack of effective treatments has been linked to diverse factors, including target selection, tumour heterogeneity and poor penetrance of therapeutic agents through the blood-brain barrier and into tumours. Therapies using monoclonal antibodies, alone or linked to cytotoxic payloads, have proved beneficial for patients with different solid tumours; these approaches are currently being explored in patients with glioblastoma. In this Review, we summarise clinical data regarding antibody-drug conjugates (ADCs) against a variety of targets in glioblastoma, and compare the efficacy and toxicity of targeting EGFR with ADCs versus naked antibodies in order to illustrate key aspects of the use of ADCs in this malignancy. Finally, we discuss the complex challenges related to the biology and mutational changes of glioblastoma that can affect the use of ADC-based therapies in patients with this disease, and highlight potential strategies to improve efficacy.

Improved anti-glioblastoma efficacy by IL-13Rα2 mediated copolymer nanoparticles loaded with paclitaxel

Glioma presents one of the most malignant brain tumors, and the therapeutic effect is often limited due to the existence of brain tumor barrier. Based on interleukin-13 receptor α2 (IL-13Rα2) over-expression on glioma cell, it was demonstrated to be a potential receptor for glioma targeting. In this study, Pep-1-conjugated PEGylated nanoparticles loaded with paclitaxel (Pep-NP-PTX) were developed as a targeting drug delivery system for glioma treatment. The Pep-NP-PTX presented satisfactory size of 95.78 nm with narrow size distribution. Compared with NP-PTX, Pep-NP-PTX exhibited significantly enhanced cellular uptake in C6 cells (p < 0.001). The in vitro anti-proliferation evaluation showed that the IC50 were 146 ng/ml and 349 ng/ml of Pep-NP-PTX and NP-PTX, respectively. The in vivo fluorescent image results indicated that Pep-NP had higher specificity and efficiency in intracranial tumor accumulation. Following intravenous administration, Pep-NP-PTX could enhance the distribution of PTX in vivo glioma section, 1.98, 1.91 and 1.53-fold over that of NP-PTX group after 0.5, 1 and 4 h, respectively. Pep-NP-PTX could improve the anti-glioma efficacy with a median survival time of 32 days, which was significantly longer than that of PTX-NP (23 days) and Taxol(®) (22 days). In conclusion, Pep-NP-PTX is a potential targeting drug delivery system for glioma treatment.

Significance of interleukin-13 receptor alpha 2-targeted glioblastoma therapy

Glioblastoma multiforme (GBM) remains one of the most lethal primary brain tumors despite surgical and therapeutic advancements. Targeted therapies of neoplastic diseases, including GBM, have received a great deal of interest in recent years. A highly studied target of GBM is interleukin-13 receptor α chain variant 2 (IL13Rα2). Targeted therapies against IL13Rα2 in GBM include fusion chimera proteins of IL-13 and bacterial toxins, nanoparticles, and oncolytic viruses. In addition, immunotherapies have been developed using monoclonal antibodies and cell-based strategies such as IL13Rα2-pulsed dendritic cells and IL13Rα2-targeted chimeric antigen receptor-modified T cells. Advanced therapeutic development has led to the completion of phase I clinical trials for chimeric antigen receptor-modified T cells and phase III clinical trials for IL-13-conjugated bacterial toxin, with promising outcomes. Selective expression of IL13Rα2 on tumor cells, while absent in the surrounding normal brain tissue, has motivated continued study of IL13Rα2 as an important candidate for targeted glioma therapy. Here, we review the preclinical and clinical studies targeting IL13Rα2 in GBM and discuss new advances and promising applications.

Peptide-pulsed dendritic cell vaccination targeting interleukin-13 receptor α2 chain in recurrent malignant glioma patients with HLA-A*24/A*02 allele

BACKGROUND AIMS

Dendritic cell (DC)-based vaccination targeting tumor-associated antigens is an attractive approach to overcoming the limitations of current treatments for malignant gliomas (MG). Interleukin-13 receptor α2 chain (IL-13Rα2) is a promising target because of its abundant and specific expression in MG. We conducted a phase I trial of DC vaccination in patients with recurrent MG using two IL-13Rα2-derived peptides restricted to HLA-A*0201 and -A*2402. The objective was to evaluate the safety and clinical and immunologic responses.

METHODS

Eight recurrent MG patients were enrolled. DC were generated from peripheral blood and pulsed with HLA-matched peptide; 1 × 10(7) DC were administered every 2 weeks for a maximum of six immunizations. The T-cell response in peripheral blood was evaluated by tetramer and ELISPOT assays in HLA-A*2402 patients.

RESULTS

All enrolled patients except one completed at least four DC vaccinations. No severe adverse events were observed. A positive T-cell response was detected in two out of three evaluable HLA-A*2402 patients. One patient achieved stable disease for 16 months and another patient showed a dramatic regression for one lesion for 4 months.

CONCLUSIONS

The regimen was feasible and safe, and the HLA-A*24-restricted peptide exhibited a capacity to induce immune responses. These results warrant further studies to evaluate whether add-on regimens to post-operative chemoradiotherapy delays recurrence in newly diagnosed MG patients.

Imbalance of Th1 and Th2 cells in cardiac injury induced by ambient fine particles

The study was to explore the potential immunoregulatory mechanisms linking fine particles and cardiac injury. Wistar kyoto (WKY) rats were exposed by intratracheal instillation to fine particles with the doses of 0.0, 1.6, 8.0 and 40.0mg/kg b.w., respectively. The exposure was conducted once a day, for three consecutive days. Twenty-four hours after the last exposure, the rats were sacrificed. Th1- and Th2-related transcription factors and cytokines were assessed in left ventricle of rats. The mRNA expressions of Th1- and Th2-related transcription factors signal transducer and activator of transcriptionl 1 (STAT1), signal transducer and activator of transcriptional 6 (STAT6), GATA-3 and T-bet were assessed in left ventricle of rats using real-time PCR. Meanwhile, the levels of Th1- and Th2-related cytokines IL-4, IL-13 and interferon gamma (IFN-γ) were determined by ELISA kits in cardiac homogenate supernatant of rats. Furthermore, the protein expression of IL-4 and IFN-γ were detected in myocardium by Western blot. The results of cardiac histology demonstrated exacerbated cardiac lesions and histological characterization of inflammation and degeneration in rats after exposure to fine particles. Moreover, fine particles induced significant increase of IL-4 and IL-13 and decrease of IFN-γ in myocardium of rats. The mRNA expression of STAT1, STAT6 and GATA-3 were up-regulated in left ventricle of rats in a dose-dependent manner, whereas T-bet was significantly down-regulated. The variations of these cytokines demonstrated the imbalance of Th1 and Th2 cytokines existed in cardiac injuries induced by fine particle. The imbalance of Th1/Th2 cytokines might be one of the mechanisms of immunotoxicity of cardiovascular system induced by ambient fine particles.