Cytokine receptor as a sensitizer for targeted cancer therapy

Identification and Validation of UPF1 as a Novel Prognostic Biomarker in Renal Clear Cell Carcinoma

Background: Up frameshift protein 1 (UPF1) is a key component of nonsense-mediated mRNA decay (NMD) of mRNA containing premature termination codons (PTCs). The dysregulation of UPF1 has been reported in various cancers. However, the expression profile of UPF1 and its clinical significance in clear cell renal cell carcinoma (ccRCC) remains unclear. Methods: In order to detect UPF1 expression in ccRCC and its relationship with the clinical features of ccRCC, bulk RNA sequencing data were analyzed from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO) and ArrayExpress databases. The impact of UPF1 on the immune microenvironment of ccRCC was evaluated by multiple immune scoring algorithms to identify the cell groups that typically express UPF1 using ccRCC single cell sequencing (scRNA) data. In addition, genes co-expressed with UPF1 were identified by the weighted gene correlation network analysis (WGCNA), followed by KEGG and Reactome enrichment analysis. A series of functional experiments were performed to assess the roles of UPF1 in renal cancer cells. Finally, pan-cancer analysis of UPF1 was also performed. Results: Compared with normal tissues, the expression levels of UPF1 mRNA and protein in tumor tissues of ccRCC patients decreased significantly. In addition, patients with low expression of UPF1 had a worse prognosis. Analysis of the immune microenvironment indicated that UPF1 immune cell infiltration was closely related and the ccRCC scRNA-seq data identified that UPF1 was mainly expressed in macrophages. WGCNA analysis suggested that the functions of co-expressed genes are mainly enriched in cell proliferation and cellular processes. Experimental tests showed that knockdown of UPF1 can promote the invasion, migration and proliferation of ccRCC cells. Lastly, pan-cancer analysis revealed that UPF1 disorders were closely associated with various cancer outcomes. Conclusions: UPF1 may play a tumor suppressive role in ccRCC and modulate the immune microenvironment. The loss of UPF1 can predict the prognosis of ccRCC, making it a promising biomarker and providing a new reference for prevention and treatment.

IL-13 and IL-13Rα1 are overexpressed in extranodal natural killer/T cell lymphoma and mediate tumor cell proliferation

Extranodal NK/T cell lymphoma (NKTCL) is a rare but aggressive subtype of non-Hodgkin lymphoma. Multi-agent chemotherapy and involved-field radiotherapy are used to treat this disease, but the prognosis remains poor. Interleukin 13 and its receptors (IL-13Rs) are correlated with the pathogenesis and progression of various malignances. However, their roles in NKTCL have not been evaluated. In this study, we examined the roles of IL-13 and IL-13Rs in NKTCL and the underlying mechanisms. We found significantly higher serum IL-13 levels (p < 0.001) and IL-13Rα1 expression in tumor tissues (36 of 40, p < 0.001) in patients with NKTCL than in control cohort. IL-13 secretion was observed in tumor tissues (30 of 40, p < 0.001) and several cell lines of NKTCL. However, we did not detect significant associations between clinical characteristics and the expression levels of IL-13 or IL-13Rs. In vitro, IL-13 activated Stat6 and promoted cell proliferation in a dose-dependent manner. In addition, blocking IL-13 exerted a negative effect on tumor cell growth. We conclude that IL-13 functions as an autocrine growth factor in NKTCL and contributes to its pathogenesis. Blocking IL-13 is thus a potential therapeutic approach for NKTCL.

HER-2/neu raises SHP-2, stops IFN-γ anti-proliferation in bladder cancer

Gene amplification or HER-2/neu protein overexpression signals a poor outcome for bladder cancer patients. We investigated the anti-proliferative effect of IFN-gamma in HER-2/neu-transfected human bladder cancer cells (TCC-N5 and TCC-N10). The cells continued growing after IFN-gamma stimulation but did not activate the Janus kinase (Jak)/Stat pathway. We found Jak/Stat protein phosphatase in TCC-N5 and TCC-N10 cells with upregulated Src homology 2-containing protein tyrosine phosphatase-2 (SHP-2). After the cells had been treated with AG825, a HER-2/neu-specific inhibitor, SHP-2 expression declined, and Jak2/Stat1 reactivated. Similar results were reported in a mouse bladder cancer cell line, MBT2, with constitutive HER-2/neu overexpression. Further, AG825 pretreatment restored the anti-proliferation activity of IFN-gamma in TCC-N5 and TCC-N10 cells. Therefore, the suppression of IFN-gamma signaling in HER-2/neu-overexpressing bladder cancer cells might be due to SHP-2 upregulation. The regulation of SHP-2 by HER-2/neu provides a new target for blocking the HER-2/neu oncogenic pathway.

A recombinant IL-4-Pseudomonas exotoxin inhibits protein synthesis and overcomes apoptosis resistance in human CLL B cells

We have determined that CLL B cells consistently express type 3 membrane receptors for the Th2-derived cytokine IL-4 (IL-4R). Furthermore, when added to CLL B cells, IL-4 induces increased apoptosis resistance, increased protein synthesis in CLL B cells and rapid onset activation of STAT1, STAT5 and STAT6. Since the IL-4-IL-4R pathway is intact in CLL B cells and is related to apoptosis resistance, we considered whether we could target this pathway. A recombinant IL-4 Pseudomonas exotoxin fusion protein (IL-4 PE), known to bind to IL-4R, was incubated with CLL B cells. IL-4 PE (10 ng/ml) cultured with CLL B cells resulted in an increase of apoptosis/death from mean levels of 46.6+/-7.0 of non-exposed cells to 69+/-8.6 (n=6). By measuring in vitro protein synthesis, two predominant patterns of sensitivity were observed. In one, CLL B cell clones (n=4) were found to be extremely sensitive to IL-4 PE (IC50's range=6-25 ng/ml). In the second, low concentrations of IL-4 PE induced agonist activity while increasing concentrations induced cytotoxicity in 6 of 21 patient-derived cells. These studies suggest that the IL-4R, on B-CLL cells, can serve as a unique molecular target for directing cytotoxic agents in the therapy of B-CLL.

Analysis of target genes induced by IL-13 cytotoxin in human glioblastoma cells

IL-13 cytotoxin comprised of IL-13 and a mutated form of Pseudomonas exotoxin (fusion protein termed IL-13-PE38QQR) has been shown to inhibit protein synthesis leading to necrotic and apoptotic cell death in glioblastoma cells that express high levels of interleukin-13 receptors (IL-13R). To identify target genes of cell death and other cellular genes with IL-13 receptors in glioblastoma cells, we utilized the cDNA microarrays to analyze global gene expression profiles after IL-13 cytotoxin and IL-13 treatment. IL-13 cytotoxin mediated cytotoxicity to U251 cells in a dose-dependent manner. Hierarchical cluster analysis of differentially expressed genes in U251 glioma cells at different time points after IL-13 cytotoxin treatment showed three major groups, each representing a specific expression pattern. Randomly selected differentially expressed genes from each group were confirmed by RT-PCR analysis. Most down-regulated genes belong to cell adhesion, motility, angiogenesis, DNA repair, and metabolic pathways. While up-regulated genes belong to cell cycle arrest, apoptosis, signaling and various metabolic pathways. Unexpectedly, at early time points, both IL-13 and IL-13 cytotoxin induced several genes belonging to different pathways most notably IL-8, DIO2, END1, and ALDH1A3 indicating that these genes are early response genes and their products may be associated with IL-13R. In addition, IL-13 cytotoxin induced IL-13Ralpha2 mRNA expression during the treatment in glioma cells. Our results indicate that novel cellular genes are involved with IL-13 receptors and that IL-13 cytotoxin induced cell death involves various target genes in human glioblastoma cells. On going studies will determine the role of associated genes and their products in the IL-13R functions in glioma cells.

IL-13 receptor-targeted cytotoxin cancer therapy leads to complete eradication of tumors with the aid of phagocytic cells in nude mice model of human cancer

Tumor-directed therapeutic approaches require unique or overexpressed specific Ag or receptor as a target to achieve selective tumor killing. However, heterogeneous expression of these targets on tumor cells limits the efficacy of this form of therapy. In this study, we forced abundant expression of IL-13Ralpha2 chain by plasmid-mediated gene transfer in head and neck, as well as prostate tumors to provide a potential target. This was followed by successfully treating xenograft tumor-bearing nude mice with IL-13R-directed cytotoxin (IL13-PE38QQR). Although we did not observe an indirect cytotoxic bystander effect conveyed to nontransduced tumor cells in vitro, our approach in vivo led to a complete regression of established tumors transfected with IL-13Ralpha2 chain in most animals. We found that the tumor eradication was achieved in part by infiltration of macrophages and NK cells, assessed by immunohistochemistry. Moreover, head and neck tumors xenografted in macrophage-depleted nude mice were less sensitive to the antitumor effect of IL-13 cytotoxin. Because we did not observe vector-related toxicity in any vital organs, our novel combination strategy of gene transfer of IL-13Ralpha2 chain and receptor-directed cytotoxin therapy may be a useful approach for the treatment of localized cancer.