Identification and characterisation of novel CAR-T cells to target IL13Rα2 positive human glioma in vitro and in vivo.

BACKGROUND: Previously, we discovered that human solid tumours, but not normal human tissues, preferentially overexpress interleukin-13Receptor alpha2, a high binding receptor for IL-13. To develop novel anti-cancer approaches, we constructed a chimeric antigen receptor construct using a high binding and codon optimised scFv-IL-13Rα2 fragment fused with CD3ζ and co-stimulatory cytoplasmic domains of CD28 and 4-1BB. METHODS: We developed a scFv clone, designated 14-1, by biopanning the bound scFv phages using huIL-13Rα2Fc chimeric protein and compared its binding with our previously published clone 4-1. We performed bioinformatic analyses for complementary determining regions (CDR) framework and residue analyses of the light and heavy chains. This construct was packaged with helper plasmids to produce CAR-lentivirus and transduced human Jurkat T or activated T cells from peripheral blood mononuclear cells (PBMCs) to produce CAR-T cells and tested for their quality attributes in vitro and in vivo. Serum enzymes including body weight from non-tumour bearing mice were tested for assessing general toxicity of CAR-T cells. RESULTS: The binding of 14-1 clone is to IL-13Rα2Fc-chimeric protein is ∼5 times higher than our previous clone 4-1. The 14-1-CAR-T cells grew exponentially in the presence of cytokines and maintained phenotype and biological attributes such as cell viability, potency, migration and T cell activation. Clone 14-1 migrated to IL-13Rα2Fc and cell free supernatants only from IL-13Rα2+ve confluent glioma tumour cells in a chemotaxis assay. scFv-IL-13Rα2-CAR-T cells specifically killed IL-13Rα2+ve but not IL-13Rα2-ve tumour cells in vitro and selectively caused significant release of IFN-γ only from IL-13Rα2+ve co-cultures. These CAR-T cells regressed IL-13Rα2+ve glioma xenografts in vivo without any general toxicity. In contrast, the IL-13Rα2 gene knocked-down U251 and U87 xenografts failed to respond to the CAR-T therapy. CONCLUSION: Taken together, we conclude that the novel scFv-IL-13Rα2 CAR-T cell therapy may offer an effective therapeutic option after designing a careful pre-clinical and clinical study.

IL13Rα2 as a crucial receptor for Chi3l1 in osteoclast differentiation and bone resorption through the MAPK/AKT pathway.

BACKGROUND: Previous research has revealed that the 18 glycoside hydrolase gene family (GH18) member Chitinase 3-like 1 (Chi3l1) can regulate osteoclast differentiation and bone resorption. However, its downstream receptors and molecular mechanisms during osteoclastogenesis have yet to be elucidated. METHODS: Initially, we conducted a comprehensive investigation to evaluate the effects of recombinant Chi3l1 protein or Chi3l1 siRNA on osteoclast differentiation and the RANKL-induced MAPK/AKT signaling pathways. Moreover, we used immunofluorescence and immunoprecipitation assays to identify IL13Rα2 as the downstream receptor of Chi3l1. Subsequently, we investigated the impact of IL13Rα2 recombinant protein or IL13Rα2-siRNA on osteoclast differentiation and the associated signaling pathways. Finally, we performed in vivo experiments to examine the effect of recombinant IL13Rα2 protein in an LPS-induced mouse model of cranial osteolysis. RESULTS: Our findings highlight that the administration of recombinant Chi3l1 protein increased the formation of osteoclasts and bolstered the expression of several osteoclast-specific genes (TRAP, NFATC1, CTR, CTSK, V-ATPase d2, and Dc-STAMP). Additionally, Chi3l1 significantly promoted the RANKL-induced MAPK (ERK/P38/JNK) and AKT pathway activation, whereas Chi3l1 silencing inhibited this process. Next, using immunofluorescence and co-immunoprecipitation assays, we identified IL13Rα2 as the binding partner of Chi3l1 during osteoclastogenesis. IL13Rα2 recombinant protein or IL13Rα2-siRNA also inhibited osteoclast differentiation, and IL13Rα2-siRNA attenuated the RANKL-induced activation of the MAPK (ERK/P38/JNK) and AKT pathways, similar to the effects observed upon silencing of Chi3l1. Moreover, the promoting effect of recombinant Chi3l1 protein on osteoclastogenesis and the activation of the MAPK and AKT pathways was reversed by IL13Rα2 siRNA. Finally, recombinant LI13Rα2 protein significantly attenuated the LPS-induced cranial osteolysis and the number of osteoclasts in vivo. CONCLUSIONS: Our findings suggested that IL13Rα2 served as a crucial receptor for Chi3l1, enhancing RANKL-induced MAPK and AKT activation to promote osteoclast differentiation. These findings provide valuable insights into the molecular mechanisms of Chi3l1 in osteoclastogenesis, with potential therapeutic implications for osteoclast-related diseases. Video Abstract.

Schnurri-3 drives tumor growth and invasion in cancer cells expressing interleukin-13 receptor alpha 2.

Interleukin 13 receptor alpha 2 (IL13Rα2) is a relevant therapeutic target in glioblastoma (GBM) and other tumors associated with tumor growth and invasion. In a previous study, we demonstrated that protein tyrosine phosphatase 1B (PTP1B) is a key mediator of the IL-13/IL13Rα2 signaling pathway. PTP1B regulates cancer cell invasion through Src activation. However, PTP1B/Src downstream signaling mechanisms that modulate the invasion process remain unclear. In the present research, we have characterized the PTP1B interactome and the PTP1B-associated phosphoproteome after IL-13 treatment, in different cellular contexts, using proteomic strategies. PTP1B was associated with proteins involved in signal transduction, vesicle transport, and with multiple proteins from the NF-κB signaling pathway, including Tenascin-C (TNC). PTP1B participated with NF-κB in TNC-mediated proliferation and invasion. Analysis of the phosphorylation patterns obtained after PTP1B activation with IL-13 showed increased phosphorylation of the transcription factor Schnurri-3 (SHN3), a reported competitor of NF-κB. SHN3 silencing caused a potent inhibition in cell invasion and proliferation, associated with a down-regulation of the Wnt/ß-catenin pathway, an extensive decline of MMP9 expression and the subsequent inhibition of tumor growth and metastasis in mouse models. Regarding clinical value, high expression of SHN3 was associated with poor survival in GBM, showing a significant correlation with the classical and mesenchymal subtypes. In CRC, SHN3 expression showed a preferential association with the mesenchymal subtypes CMS4 and CRIS-B. Moreover, SHN3 expression strongly correlated with IL13Rα2 and MMP9-associated poor prognosis in different cancers. In conclusion, we have uncovered the participation of SNH3 in the IL-13/IL13Rα2/PTP1B pathway to promote tumor growth and invasion. These findings support a potential therapeutic value for SHN3.

Gastrodin synergistically increases migration of interleukin-13 receptor α2 chimeric antigen receptor T cell to the brain against glioblastoma multiforme: A preclinical study.

Therapy with chimeric antigen receptor T (CAR-T) cells involves using reformative T lymphocytes that have three domains, antigen recognition, transmembrane, and costimulating to achieve the therapeutic purpose. CAR-T therapy on malignant hematologic has been successful; however, its effectiveness in patients with solid tumors is still limited. Few studies exist confirming the efficacy of natural products on the function of CAR-T cells. The purpose of this study is to assess the effect of gastrodin (GAS) on CAR-T cells that target interleukin-13 receptor α2 antigen (IL-13Rα2 CAR-T) in the brain against glioblastoma multiforme. Migration of IL-13Rα2 CAR-T was evaluated using the Transwell assay. The effects of GAS on IL-13Rα2 CAR-T cells were assessed both in vitro and situ glioblastoma models. The cytoskeleton was stained with Fluorescein 5-isothiocyanate (FITC)-phalloidin. Cytokines expression in cells was determined by flow cytometry and ELISA assay. Western blotting was used to detect the S1P1 expression, and quantitative PCR assay was used to determine the IL-13Rα2 gene level. GAS increased the migratory and destructive capacity of IL-13Rα2 CAR-T cells with no effect on cytokine release. By increasing the expression of S1P1, GAS encouraged the entry of CAR-T cells into the brain and bone marrow. Transcriptomic analysis revealed that genes related to skeletal migration such as add2 and gng8 showed increased expression in GAS-treated CAR-T cells. We found that GAS synergistically improves the mobility of IL-13Rα2 CAR-T, enhancing their ability to recognize the tumor antigen of glioblastoma, which could be advantageous for the application of CAR-T for the treatment of solid tumors.

Bi-Specific Killer Cell Engager Enhances NK Cell Activity against Interleukin-13 Receptor Alpha-2 Positive Gliomas.

Glioblastoma (GBM) is a lethal brain tumor with limited therapeutic options. Bi-specific killer cell engagers (BiKEs) are novel immunotherapies designed to engage natural killer (NK) cells against cancer. We designed a BiKE molecule consisting of a single-domain CD16 antibody, an interleukin-15 linker, and a single-chain variable antibody against the glioma-associated antigen interleukin 13 receptor alpha 2 (IL13Rα2). Recombinant BiKE protein was expressed in HEK cells and purified. Flow cytometric analysis of co-cultures of peripheral blood-derived NK cells with GBM6 and GBM39 patient-derived xenograft lines revealed significantly increased activation of NK cells (CD25+CD69+) and increased glioma cell killing following BiKE treatment compared to controls (n = 4, p < 0.01). Glioma cell killing was also confirmed via immunofluorescence staining for cleaved caspase-3 (p < 0.05). In vivo, intracranial delivery of NK cells with BiKE extended median survival in mice bearing GBM6 (p < 0.01) and GBM12 (p < 0.01) tumors compared to controls. Finally, histological analysis of brain tissues revealed a higher frequency of peritumoral NK cells in mice treated with BiKE than with NK cells alone (p < 0.05). In conclusion, we demonstrate that a BiKE generated in a mammalian expression system is functional in augmenting NK cell targeting of IL13Rα2-positive gliomas.

Targeting glioblastoma multiforme using a novel fusion protein comprising interleukin-13 and staphylococcal enterotoxin B in vitro.

Targeting cell surface receptors with immunotoxins provides a novel, unique and highly potent treatment against cancers. A high expression of interleukin-13 (IL13) receptor α2 (IL13Rα2) has been reported in different types of cancers including glioblastoma multiforme (GBM). In this paper, to target IL13Rα2 on GBM cells, a fusion protein was generated comprising human IL13 and staphylococcal enterotoxin B (SEB), termed IL13-linker-SEB. The fusion protein was cloned into pET28a(+) and expressed in Escherichia coli strain BL21 (DE3); U251 (IL13Rα2-positive) and T98G (IL13Rα2-negative) GBM cell lines were employed and the functional activity of IL13-linker-SEB was evaluated by cell ELISA, cytotoxicity (MTT and LDH), apoptosis (flow cytometry and caspase-3 activity), adhesion, scratch and RT-PCR tests. SEB and chemotherapeutic drugs were employed to be compared to IL13-linker-SEB function. The IL13-linker-SEB exhibited higher binding affinity and cytotoxicity compared to SEB on U251 cells, although both recombinant proteins had shown similar behavior regarding T98G cells. Furthermore, the highest induction of apoptosis was observed in U251 cells treated with IL13-linker-SEB which was confirmed by Bax/Bcl-2 ratio. The expression of MMP2, MMP9 and VEGFR2 in U251 cells experienced a significant reduction after treatment with IL13-linker-SEB compared to SEB and T98G treated cells. The data showed that IL13-linker-SEB can be considered as a novel potential agent for GBM treatment; however, further research is needed to investigate the efficacy.

Myeloid-specific deletion of chitinase-3-like 1 protein ameliorates murine diet-induced steatohepatitis progression.

Chitinase-3-like 1 protein (CHI3L1) is a secreted glycoprotein, strongly correlated with fibrosis severity in chronic liver diseases including non-alcoholic steatohepatitis (NASH). However, the mechanisms by which CHI3L1 contributes to fibrogenesis remain undefined. Here, we showed that infiltrating monocyte-derived liver macrophages represent the main source of CHI3L1 in murine NASH. We developed a floxed CHI3L1 knock-out (KO) mouse to further study the cell-specific role of CHI3L1 ablation. Wildtype (WT) and myeloid cell-specific CHI3L1 KO mice (CreLyz) were challenged with a highly inflammatory and fibrotic dietary model of NASH by administering choline-deficient high-fat diet for 10 weeks. Macrophage accumulation and inflammatory cell recruitment were significantly ameliorated in the CreLyz group compared to WT (F4/80 IHC p < 0.0001, CD11b IHC p < 0.0001). Additionally, hepatic stellate cell (HSC) activation and fibrosis were strongly decreased in this group (α-SMA IHC p < 0.0001, picrosirius red staining p < 0.0001). In vitro studies were performed stimulating bone marrow derived macrophages, THP-1 (human monocytes) and LX2 (human HSCs) cells with recombinant CHI3L1 to dissect its relationship with fibrosis development. Results showed an important role of CHI3L1 regulating fibrosis-promoting factors by macrophages (TGFB1 p < 0.05, CTGF p < 0.01) while directly activating HSCs (ACTA2 p < 0.01, COL1A1 p < 0.01), involving IL13Rα2 as the potential mediator. Our findings uncovered a novel role of CHI3L1 derived from liver macrophages in NASH progression and identifies this protein as a potential anti-fibrotic therapeutic target. KEY MESSAGES: We showed that CHI3L1 expression is increased in murine CDAA-HFAT diet NASH model, and that infiltrating macrophages are a key source of CHI3L1 production. Myeloid cell-specific CreLyz CHI3L1 knock-out in mice fed with CDAA-HFAT diet improved the NASH phenotype, with significantly reduced accumulation of pro-inflammatory macrophages and neutrophils compared with WT group. DEG and qPCR analysis of genes in CreLyz CHI3L1 knock-out mouse liver showed the mechanistic role of CHI3L1 in cellular chemotaxis. HSC is directly activated by CHI3L1 via receptor IL13Rα2, leading to upregulation of collagen deposition and pro-fibrotic gene, TIMP-1 and TIMP-2 release in whole liver. Direct stimulation of macrophages with CHI3L1 leads to upregulated expression of HSC-activation factors, suggesting its role in modulating macrophage-HSC crosstalk.

Targeting of the Interleukin-13 Receptor (IL-13R)α2 Expressing Prostate Cancer by a Novel Hybrid Lytic Peptide.

The IL-13Rα2 cell surface receptor is highly expressed in tumours such as prostate cancer. In this report, we evaluated the hypothesis that prostate cancer cells with enhanced IL-13Rα2 expression are a suitable target for the hybrid lytic peptide (Pep-1-Phor21) peptide, which is generated by fusing the IL-13Rα2 specific ligand (Pep-1) and a cell membrane disrupting lytic peptide (Phor21). The expression of IL-13Rα2 mRNA and protein in prostate cancer tissues and cell lines was assessed via real-time PCR (RT-PCR) and immunoblotting. The effect of Pep-1-Phor21 on the viability of prostate cancer cells grown in monolayers (2D) and microtissue spheroids (3D) was assessed via CellTox green cytotoxic assay. IL-13Rα2 expression and Pep-1-Phor21-mediated killing were also determined in the cells treated with epigenetic regulators (Trichostatin A (TSA) and 5-aza-2 deoxycytidine (5-Aza-dC)). The hybrid lytic peptide cytotoxic activity correlated with the expression of IL-13Rα2 in prostate cancer cell lines cultured as monolayers (2D) or 3D spheroids. In addition, TSA or 5-Aza-dC treatment of prostate cancer cells, particularly those with low expression of IL-13Rα2, enhanced the cells' sensitivity to the lytic peptide by increasing IL-13Rα2 expression. These results demonstrate that the Pep-1-Phor21 hybrid lytic peptide has potent and selective anticancer properties against IL-13Rα2-expressing prostate cancer cells.

Plasma IL13Rα2 as a novel liquid biopsy biomarker for glioblastoma.

PURPOSE: Glioblastoma (GBM) is the most common and deadliest brain tumor with unrelenting and rapid disease progression. The standard of care for GBM is surgical excision followed by radiation with concurrent and adjuvant temozolomide-centered chemotherapy (TMZ). Treatment failure and resistance is the rule and despite advances in imaging technology, early detection of treatment failure or impending resistance remains a challenge. There is a dire, unmet, need in clinical practice for minimally-invasive diagnostic tools to enable timely understanding of disease progression and treatment response. Here, we aim to address this clinical need by leveraging a unique characteristic of GBM: the overexpression of the α2 variant of the IL-13 receptor in over 75% of GBM tumors. METHODS: In this study we examined patients with primary GBM from Penn State and Cleveland Clinic compared to healthy controls. RESULTS: IL13Rα2 was detectable in plasma of GBM patients using ELISA but detection could be optimized by PEG precipitation to enrich for extracellular vesicles (EVs). Patients with GBM had elevated levels of plasma IL13Rα2, which correlated to levels of this receptor in the tumor tissue. Elevated plasma levels of IL13Rα2 predicted longer overall survival (OS) (19.8 vs. 13.2 months). Similarly, detection of IL13Rα2 + cells in tumor tissue also predicted longer OS (22.1 vs. 12.2 months). CONCLUSION: These findings strongly suggest that expression of the IL13Rα2 receptor confer survival advantage in GBM patients, which can be determined through a minimally-invasive liquid biopsy. Detection of plasma IL13Rα2 can also be used to select GBM patients for targeted tumor therapy.

Interleukin 13 receptor alpha 2 (IL13Rα2): Expression, signaling pathways and therapeutic applications in cancer.

Interleukin 13 receptor alpha 2 (IL13Rα2) is increasingly recognized as a relevant player in cancer invasion and metastasis. Despite being initially considered a decoy receptor for dampening the levels of interleukin 13 (IL-13) in diverse inflammatory conditions, accumulating evidences in the last decades indicate the capacity of IL13Rα2 for mediating IL-13 signaling in cancer cells. The biological reasons behind the expression of this receptor with such extremely high affinity for IL-13 in cancer cells remain unclear. Elevated expression of IL13Rα2 is commonly associated with invasion, late stage and cancer metastasis that results in poor prognosis for glioblastoma, colorectal or breast cancer, among others. The discovery of new mediators and effectors of IL13Rα2 signaling has been critical for deciphering its underlying molecular mechanisms in cancer progression. Still, many questions about the effects of inflammation, the cancer type and the tumor degree in the expression of IL13Rα2 remain largely uncharacterized. Here, we review and discuss the current status of the IL13Rα2 biology in cancer, with particular emphasis in the role of inflammation-driven expression and the regulation of different signaling pathways. As IL13Rα2 implications in cancer continue to grow exponentially, we highlight new targeted therapies recently developed for glioblastoma, colorectal cancer and other IL13Rα2-positive tumors.

Spatial organization of heterogeneous immunotherapy target antigen expression in high-grade glioma.

High-grade (WHO grades III-IV) glioma remains one of the most lethal human cancers. Adoptive transfer of tumor-targeting chimeric antigen receptor (CAR)-redirected T cells for high-grade glioma has revealed promising indications of anti-tumor activity, but objective clinical responses remain elusive for most patients. A significant challenge to effective immunotherapy is the highly heterogeneous structure of these tumors, including large variations in the magnitudes and distributions of target antigen expression, observed both within individual tumors and between patients. To obtain a more detailed understanding of immunotherapy target antigens within patient tumors, we immunochemically mapped at single cell resolution three clinically-relevant targets, IL13Rα2, HER2 and EGFR, on tumor samples drawn from a 43-patient cohort. We observed that within individual tumor samples, expression of these antigens was neither random nor uniform, but rather that they mapped into local neighborhoods - phenotypically similar cells within regions of cellular tumor - reflecting not well understood properties of tumor cells and their milieu. Notably, tumor cell neighborhoods of high antigen expression were not arranged independently within regions. For example, in cellular tumor regions, neighborhoods of high IL13Rα2 and HER2 expression appeared to be reciprocal to those of EGFR, while in areas of pseudopalisading necrosis, expression of IL13Rα2 and HER2, but not EGFR, appeared to reflect the radial organization of tumor cells around hypoxic cores. Other structural features affecting expression of immunotherapy target antigens remain to be elucidated. This structured but heterogeneous organization of antigen expression in high grade glioma is highly permissive for antigen escape, and combinatorial antigen targeting is a commonly suggested potential mitigating strategy. Deeper understanding of antigen expression within and between patient tumors will enhance optimization of combination immunotherapies, the most immediate clinical application of the observations presented here being the importance of including (wild-type) EGFR as a target antigen.

Targeting interleukin-13 receptor α2 (IL-13Rα2) for glioblastoma therapy with surface functionalized nanocarriers.

Despite surgical and therapeutic advances, glioblastoma multiforme (GBM) is among the most fatal primary brain tumor that is aggressive in nature. Patients with GBM have a median lifespan of just 15 months when treated with the current standard of therapy, which includes surgical resection and concomitant chemo-radiotherapy. In recent years, nanotechnology has shown considerable promise in treating a variety of illnesses, and certain nanomaterials have been proven to pass the blood-brain barrier (BBB) and stay in glioblastoma tissues. Recent preclinical research suggests that the diagnosis and treatment of brain tumor is significantly explored through the intervention of nanomaterials that has showed enhanced effect. In order to elicit an antitumor response, it is necessary to retain the therapeutic candidates within glioblastoma tissues and this job is effectively carried out by nanocarrier particularly functionalized nanocarriers. In the arena of neoplastic diseases including GBM have achieved great attention in recent decades. Furthermore, interleukin-13 receptor α chain variant 2 (IL13Rα2) is a highly expressed and studied target in GBM that is lacked by the surrounding environment. The absence of IL13Rα2 in surrounding normal tissues has made it a suitable target in glioblastoma therapy. In this review article, we highlighted the role of IL13Rα2 as a potential target in GBM along with design and fabrication of efficient targeting strategies for IL13Rα2 through surface functionalized nanocarriers.

Recent Advances in IL-13Rα2-Directed Cancer Immunotherapy.

Interleukin-13 receptor subunit alpha-2 (IL-13Rα2, CD213A), a high-affinity membrane receptor of the anti-inflammatory Th2 cytokine IL-13, is overexpressed in a variety of solid tumors and is correlated with poor prognosis in glioblastoma, colorectal cancer, adrenocortical carcinoma, pancreatic cancer, and breast cancer. While initially hypothesized as a decoy receptor for IL-13-mediated signaling, recent evidence demonstrates IL-13 can signal through IL-13Rα2 in human cells. In addition, expression of IL-13Rα2 and IL-13Rα2-mediated signaling has been shown to promote tumor proliferation, cell survival, tumor progression, invasion, and metastasis. Given its differential expression in tumor versus normal tissue, IL-13Rα2 is an attractive immunotherapy target, as both a targetable receptor and an immunogenic antigen. Multiple promising strategies, including immunotoxins, cancer vaccines, and chimeric antigen receptor (CAR) T cells, have been developed to target IL-13Rα2. In this mini-review, we discuss recent developments surrounding IL-13Rα2-targeted therapies in pre-clinical and clinical study, including potential strategies to improve IL-13Rα2-directed cancer treatment efficacy.

Pancreatic Adenocarcinoma With Strong Expression of Interleukin-13 Receptor α2 Shows a Poor Response to Gemcitabine-Based Chemotherapy.

OBJECTIVES: Pancreatic ductal adenocarcinoma with strong expression of interleukin-13 receptor α2 (IL-13Rα2) was associated with poor prognosis and gemcitabine resistance in an orthotopic mouse model. We evaluated the influence of IL-13Rα2 expression in the endoscopic ultrasound-fine needle aspiration (EUS-FNA) specimen. METHODS: We included patients with pancreatic ductal adenocarcinoma, as diagnosed by EUS-FNA, who received gemcitabine-based chemotherapy (G-CTX). Tumor expression of IL-13Rα2 was assessed by immunohistochemistry and classified using a three scale (negative, weak, or strong) in a blinded fashion. The effect of G-CTX was assessed by tumor reduction rate by computed tomography after 3 months. RESULTS: A total of 95 patients were enrolled, and 63 and 32 cases were determined with strong and weak/negative expression of IL-13Rα2. The IL-13Rα2-strong group showed significantly poorer progression-free and overall survival rates than weak/negative group (P = 0.0191 and P = 0.0062, respectively). Strong expression of IL-13Rα2 was associated with progression factor after 3 months of the first G-CTX (odds ratio, 13.72; P = 0.0143). CONCLUSIONS: Pancreatic ductal adenocarcinoma with strong expression of IL-13Rα2 in EUS-FNA specimens showed poor prognosis and poor response to G-CTX.

Chimeric Antigen Receptor T Cells With Modified Interleukin-13 Preferentially Recognize IL13Rα2 and Suppress Malignant Glioma: A Preclinical Study.

Background: Interleukin-13 receptor α 2 (IL13Rα2) is a promising tumor-directed antigen of malignant glioma (MG). Here, we examine the efficacy and safety of T cells containing a YYB-103 chimeric antigen receptor (CAR) that can preferentially bind to IL13Rα2 on MG cells. Methods: IL13 was modified on the extracellular domain by substitution of amino acids with E13K, R66D, S69D, and R109K and stably transfected into human T cells using a retroviral vector. The in vitro efficacy of YYB-103 CAR T cells was tested in cell lines with differing IL13Rα1 and IL13Rα2 expression. The in vivo efficacy of intracerebroventricular (i.c.v.) and intravenous (i.v.) routes of YYB-103 CAR T-cell administration were tested in orthotopic MG mouse models. Immunohistochemical staining of MG was performed using WHO grade 3/4 surgical specimens from 53 patients. IL13Rα2 expression was quantified by H-score calculated from staining intensity and percentage of positive cells. Results: Binding affinity assay of YYB-103 verified apparently nil binding to IL13Rα1, which was more selective than previously reported IL13 modification (E13Y). YYB-103 CAR T cells showed selective toxicity toward co-cultured U87MG (IL13Rα1+/IL13Rα2+) cells but not A431 (IL13Rα1+/IL13Rα2-) cells. Consistently, YYB-103 CAR T cells suppressed tumor growth in nude mice receiving orthotopic injection of U87 MG cells. Both i.c.v. and i.v. injections of YYB-103 CAR T cells reduced tumor volume and prolonged overall survival of tumor-bearing mice. The median H-score for IL13Rα2 in patient-derived MG tissue was 5 (mean, 57.5; SD, 87.2; range, 0 to 300). Conclusion: This preclinical study demonstrates the efficacy of IL13Rα2-targeted YYB-103 CAR T cells against MG cells. The use of modified IL13 to construct a CAR facilitated the selective targeting of IL13Rα2-expressing MG cells while sparing IL13Rα1-expressing cells. Notably, YYB-103 CAR T cells exhibited effective blood-brain barrier crossing, suggesting compatibility with i.v. administration rather than intracranial injection. Additionally, the high H-score for IL13Rα2 in glioblastoma, especially in conjunction with the poor prognostic markers of wild-type isocitrate dehydrogenase-1 (IDH-1) and unmethylated O6-methyl guanine methyl-transferase (MGMT), could be used to determine the eligibility of patients with recurrent glioblastoma for a future clinical trial of YYB-103 CAR T cells.

Construction of IL-13 Receptor α2-Targeting Resveratrol Nanoparticles against Glioblastoma Cells: Therapeutic Efficacy and Molecular Effects.

Glioblastoma multiforme (GBM) is the most common lethal primary brain malignancy without reliable therapeutic drugs. IL-13Rα2 is frequently expressed in GBMs as a molecular marker. Resveratrol (Res) effectively inhibits GBM cell growth but has not been applied in vivo because of its low brain bioavailability when administered systemically. A sustained-release and GBM-targeting resveratrol form may overcome this therapeutic dilemma. To achieve this goal, encapsulated Res 30 ± 4.8 nm IL-13Rα2-targeting nanoparticles (Pep-PP@Res) were constructed. Ultraviolet spectrophotometry revealed prolonged Res release (about 25%) from Pep-PP@Res in 48 h and fluorescent confocal microscopy showed the prolonged intracellular Res retention time of Pep-PP@Res (>24 h) in comparison with that of free Res (<4 h) and PP@Res (<4 h). MTT and EdU cell proliferation assays showed stronger suppressive effects of Pep-PP@Res on rat C6 GBM cells than that of PP@Res (p = 0.024) and Res (p = 0.009) when used twice for 4 h/day. Pep-PP@Res had little toxic effect on normal rat brain cells. The in vivo anti-glioblastoma effects of Res can be distinctly improved in the form of Pep-PP@Res nanoparticles via activating JNK signaling, upregulating proapoptosis gene expression and, finally, resulting in extensive apoptosis. Pep-PP@Res with sustained release and GBM-targeting properties would be suitable for in vivo management of GBMs.

IL13Rα2­ and EGFR­targeted pseudomonas exotoxin potentiates the TRAIL­mediated death of GBM cells.

Glioblastomas (GBMs) are refractory to current treatments and novel therapeutic approaches need to be explored. Pro­apoptotic tumor necrosis factor­related apoptosis­inducing ligand (TRAIL) is tumor­specific and has been shown to induce apoptosis and subsequently kill GBM cells. However, approximately 50% of GBM cells are resistant to TRAIL and a combination of TRAIL with other therapeutics is necessary to induce mechanism­based cell death in TRAIL­resistant GBMs. The present study examined the ability of the tumor cell surface receptor, interleukin (IL)­13 receptor α2 (IL13Rα2)­ and epidermal growth factor receptor (EGFR)­targeted pseudomonas exotoxin (PE) to sensitize TRAIL­resistant GBM cells and assessed the dual effects of interleukin 13­PE (IL13­PE) or EGFR nanobody­PE (ENb­PE) and TRAIL for the treatment of a broad range of brain tumors with a distinct TRAIL therapeutic response. Receptor targeted toxins upregulated TRAIL death receptors (DR4 and DR5) and suppressed the expression of anti­apoptotic FLICE­inhibitory protein (FLIP) and X­linked inhibitor of apoptosis protein (XIAP). This also led to the induction of the cleavage of caspase­8 and caspase­9 and resulted in the sensitization of highly resistant established GBM and patient­derived GBM stem cell (GSC) lines to TRAIL­mediated apoptosis. These findings provide a mechanism­based strategy that may provide options for the cell­mediated delivery of bi­functional therapeutics to target a wide spectrum of TRAIL­resistant GBMs.

A Distinct Macrophage Subset Mediating Tissue Destruction and Neovascularization in Giant Cell Arteritis: Implication of the YKL-40/Interleukin-13 Receptor α2 Axis.

OBJECTIVE: Macrophages mediate inflammation, angiogenesis, and tissue destruction in giant cell arteritis (GCA). Serum levels of the macrophage-associated protein YKL-40 (chitinase 3-like protein 1), previously linked to angiogenesis and tissue remodeling, remain elevated in GCA despite glucocorticoid treatment. This study was undertaken to investigate the contribution of YKL-40 to vasculopathy in GCA. METHODS: Immunohistochemistry was performed on GCA temporal artery biopsy specimens (n = 12) and aortas (n = 10) for detection of YKL-40, its receptor interleukin-13 receptor α2 (IL-13Rα2), macrophage markers PU.1 and CD206, and the tissue-destructive protein matrix metalloproteinase 9 (MMP-9). Ten noninflamed temporal artery biopsy specimens served as controls. In vitro experiments with granulocyte-macrophage colony-stimulating factor (GM-CSF)- or macrophage colony-stimulating factor (M-CSF)-skewed monocyte-derived macrophages were conducted to study the dynamics of YKL-40 production. Next, small interfering RNA-mediated knockdown of YKL-40 in GM-CSF-skewed macrophages was performed to study its effect on MMP-9 production. Finally, the angiogenic potential of YKL-40 was investigated by tube formation experiments using human microvascular endothelial cells (HMVECs). RESULTS: YKL-40 was abundantly expressed by a CD206+MMP-9+ macrophage subset in inflamed temporal arteries and aortas. GM-CSF-skewed macrophages from GCA patients, but not healthy controls, released significantly higher levels of YKL-40 compared to M-CSF-skewed macrophages (P = 0.039). In inflamed temporal arteries, IL-13Rα2 was expressed by macrophages and endothelial cells. Functionally, knockdown of YKL-40 led to a 10-50% reduction in MMP-9 production by macrophages, whereas exposure of HMVECS to YKL-40 led to significantly increased tube formation. CONCLUSION: In GCA, a GM-CSF-skewed, CD206+MMP-9+ macrophage subset expresses high levels of YKL-40 which may stimulate tissue destruction and angiogenesis through IL-13Rα2 signaling. Targeting YKL-40 or GM-CSF may inhibit macrophages that are currently insufficiently suppressed by glucocorticoids.

M2a Macrophage-Secreted CHI3L1 Promotes Extracellular Matrix Metabolic Imbalances via Activation of IL-13Rα2/MAPK Pathway in Rat Intervertebral Disc Degeneration.

The accumulation of macrophages in degenerated discs is a common phenomenon. However, the roles and mechanisms of M2a macrophages in intervertebral disc degeneration (IDD) have not been illuminated. This study investigated the expression of the M2a macrophage marker (CD206) in human and rat intervertebral disc tissues by immunohistochemistry. To explore the roles of M2a macrophages in IDD, nucleus pulposus (NP) cells were co-cultured with M2a macrophages in vitro. To clarify whether the CHI3L1 protein mediates the effect of M2a macrophages on NP cells, siRNA was used to knock down CHI3L1 transcription. To elucidate the underlying mechanisms, NP cells were incubated with recombinant CHI3L1 proteins, then subjected to western blotting analysis of the IL-13Rα2 receptor and MAPK pathway. CD206-positive cells were detected in degenerated human and rat intervertebral disc tissues. Notably, M2a macrophages promoted the expression of catabolism genes (MMP-3 and MMP-9) and suppressed the expression of anabolism genes (aggrecan and collagen II) in NP cells. These effects were abrogated by CHI3L1 knockdown in M2a macrophages. Exposure to recombinant CHI3L1 promoted an extracellular matrix metabolic imbalance in NP cells via the IL-13Rα2 receptor, along with activation of the ERK and JNK MAPK signaling pathways. This study elucidated the roles of M2a macrophages in IDD and identified potential mechanisms for these effects.

Design considerations of an IL13Rα2 antibody-drug conjugate for diffuse intrinsic pontine glioma.

Diffuse intrinsic pontine glioma (DIPG), a rare pediatric brain tumor, afflicts approximately 350 new patients each year in the United States. DIPG is noted for its lethality, as fewer than 1% of patients survive to five years. Multiple clinical trials involving chemotherapy, radiotherapy, and/or targeted therapy have all failed to improve clinical outcomes. Recently, high-throughput sequencing of a cohort of DIPG samples identified potential therapeutic targets, including interleukin 13 receptor subunit alpha 2 (IL13Rα2) which was expressed in multiple tumor samples and comparably absent in normal brain tissue, identifying IL13Rα2 as a potential therapeutic target in DIPG. In this work, we investigated the role of IL13Rα2 signaling in progression and invasion of DIPG and viability of IL13Rα2 as a therapeutic target through the use of immunoconjugate agents. We discovered that IL13Rα2 stimulation via canonical ligands demonstrates minimal impact on both the cellular proliferation and cellular invasion of DIPG cells, suggesting IL13Rα2 signaling is non-essential for DIPG progression in vitro. However, exposure to an anti-IL13Rα2 antibody-drug conjugate demonstrated potent pharmacological response in DIPG cell models both in vitro and ex ovo in a manner strongly associated with IL13Rα2 expression, supporting the potential use of targeting IL13Rα2 as a DIPG therapy. However, the tested ADC was effective in most but not all cell models, thus selection of the optimal payload will be essential for clinical translation of an anti-IL13Rα2 ADC for DIPG.