Suppression of antitumor cytokine IL‑24 by PRG4 and PAI‑1 may promote myxoid liposarcoma cell survival

Suppression of the antitumor cytokine interleukin-24 (IL-24) is critical for the survival of myxoid liposarcoma (MLS) cells. It has been previously demonstrated by the authors that an MLS-specific chimeric oncoprotein, translocated in liposarcoma-CCAAT/enhancer-binding protein homologous protein (TLS-CHOP), supresses IL24 mRNA expression via induction of proteoglycan 4 (PRG4) to sustain MLS cell proliferation. However, IL-24 has also been revealed to be suppressed by the ubiquitin-proteasome system in human ovarian and lung cancer cells. Therefore, the aim of the present study was to elucidate the mechanism of IL-24 suppression in MLS cells. The results revealed that the proteasome inhibitor, MG-132, induced cell death in MLS cells in vitro; this effect was reduced following IL-24 knockdown. This indicated that proteasomal degradation of IL-24 may be an important process for MLS cell survival. In addition, it was also previously revealed by the authors that knockdown of plasminogen activator inhibitor-1 (PAI-1), a TLS-CHOP downstream molecule, suppressed the growth of MLS cells, thus instigating the investigation of the effect of PAI-1 on IL-24 expression in MLS cells. Double knockdown of PAI-1 and IL-24 negated the growth-suppressive effect of PAI-1 single knockdown in MLS cells. Interestingly, PAI-1 single knockdown did not increase the mRNA expression of IL24, but it did increase the protein abundance of IL-24, indicating that PAI-1 suppressed IL-24 expression by promoting its proteasomal degradation. Moreover, treatment of MLS cells with a PAI-1 inhibitor, TM5275, induced IL-24 protein expression and apoptosis. Collectively, the results of the present as well as previous studies indicated that IL-24 expression may be suppressed at the transcriptional level by PRG4 and at the protein level by PAI-1 in MLS cells. Accordingly, PAI-1 may represent an effective therapeutic target for MLS treatment.

Regulation of IL-24/IL-20R2 complex formation using photocaged tyrosines and UV light

Human interleukin 24 (IL-24) is a multifunctional cytokine that represents an important target for autoimmune diseases and cancer. Since the biological functions of IL-24 depend on interactions with membrane receptors, on-demand regulation of the affinity between IL-24 and its cognate partners offers exciting possibilities in basic research and may have applications in therapy. As a proof-of-concept, we developed a strategy based on recombinant soluble protein variants and genetic code expansion technology to photocontrol the binding between IL-24 and one of its receptors, IL-20R2. Screening of non-canonical ortho-nitrobenzyl-tyrosine (NBY) residues introduced at several positions in both partners was done by a combination of biophysical and cell signaling assays. We identified one position for installing NBY, tyrosine70 of IL-20R2, which results in clear impairment of heterocomplex assembly in the dark. Irradiation with 365-nm light leads to decaging and reconstitutes the native tyrosine of the receptor that can then associate with IL-24. Photocaged IL-20R2 may be useful for the spatiotemporal control of the JAK/STAT phosphorylation cascade.

A tissue injury sensing and repair pathway distinct from host pathogen defense

Pathogen infection and tissue injury are universal insults that disrupt homeostasis. Innate immunity senses microbial infections and induces cytokines/chemokines to activate resistance mechanisms. Here, we show that, in contrast to most pathogen-induced cytokines, interleukin-24 (IL-24) is predominately induced by barrier epithelial progenitors after tissue injury and is independent of microbiome or adaptive immunity. Moreover, Il24 ablation in mice impedes not only epidermal proliferation and re-epithelialization but also capillary and fibroblast regeneration within the dermal wound bed. Conversely, ectopic IL-24 induction in the homeostatic epidermis triggers global epithelial-mesenchymal tissue repair responses. Mechanistically, Il24 expression depends upon both epithelial IL24-receptor/STAT3 signaling and hypoxia-stabilized HIF1α, which converge following injury to trigger autocrine and paracrine signaling involving IL-24-mediated receptor signaling and metabolic regulation. Thus, parallel to innate immune sensing of pathogens to resolve infections, epithelial stem cells sense injury signals to orchestrate IL-24-mediated tissue repair.

Polyethylenimine-Modified Bombyx mori Silk Fibroin as a Delivery Carrier of the ING4-IL-24 Coexpression Plasmid

One of the major challenges for lung cancer gene therapy is to find a gene delivery vector with high efficiency and low toxicity. In this study, low-molecular-weight polyethyleneimine (PEI, 1.8 kDa) was grafted onto the side chains of Bombyx mori silk fibroin (BSF) to prepare cationized BSF (CBSF), which was used to package the plasmid DNA (pDNA) encoded by the inhibitor of growth 4 (ING4) and interleukin-24 (IL-24). FTIR and 1H-NMR spectra demonstrated that PEI was effectively coupled to the side chains of BSF by amino bonds. The results of the trinitrobenzene sulfonic acid method and zeta potential showed that the free amino group content on BSF increased from 125.1 ± 1.2 µmol/mL to 153.5 ± 2.2 µmol/mL, the isoelectric point increased from 3.68 to 8.82, and the zeta potential reversed from - 11.8 ± 0.1 mV to + 12.4 ± 0.3 mV after PEI grafting. Positively charged CBSF could package pDNA to form spherical CBSF/pDNA complexes. In vitro, human lung adenocarcinoma A549 cells and human embryonic lung fibroblast WI-38 cells were transfected with CBSF/pDNA complexes. Confocal laser scanning microscopy analysis and flow cytometry tests showed that CBSF/pDNA complexes can effectively transfect A549 cells, and the transfection efficiency was higher than that of 25 kDa PEI/pDNA complexes. CCK-8 assay results showed that CBSF/pDNA complexes significantly inhibited the proliferation of A549 cells but had no significant effect on WI-38 cells and exhibited lower cytotoxicity to WI-38 cells than 25 kDa PEI. Therefore, a gene delivery system, constructed with the low-molecular-weight PEI-modified silk fibroin protein and the ING4-IL-24 double gene coexpression plasmid has potential applications in gene therapy for lung cancer.

[Mesenchymal Stem Cells Cultured in 3D System Inhibit Non-small Cell Lung Cancer Cells Through p38 MAPK and CXCR4/AKT Pathways by IL-24 Regulating]

Non-small cell lung cancer (NSCLC) is prevalent worldwide and has a high mortality rate. Even if mesenchymal stem cells (MSCs) are suggested as cancer treatment, the studies of their effects on NSCLC cells contradict each other, mainly due to utilization of two-dimensional (2D) culture system. Three-dimensional (3D) culture systems resemble tissue organization in vivo. Here we comprehensively explore the inhibitory effects of MSCs on NSCLC cells in a 3D culture system. We confirmed that the inhibitory effects of 3D-cultured MSCs (3D-MSCs) on the proliferation and migration of NSCLC cells are greater than that of the 2D-cultured MSCs. 3D-MSCs overexpress IL-24, which serve as the key factor enhancing antitumor effects of MSCs. In these cells, IL-24 affects p38 MAPK and CXCR4/AKT pathways. Overall, this study provides the support for use of MSCs in tumor.

Target Therapy With Vaccinia Virus Harboring IL-24 For Human Breast Cancer

Background: Breast cancer is a heterogeneous disease with high aggression and novel targeted therapeutic strategies are required. Oncolytic vaccinia virus is an attractive candidate for cancer treatment due to its tumor cell-specific replication causing lysis of tumor cells as well as a delivery vector to overexpress therapeutic transgenes. Interleukin-24 (IL-24) is a novel tumor suppressor cytokine that selectively induces apoptosis in a wide variety of tumor types, including breast cancer. In this study, we used vaccinia virus as a delivery vector to express IL-24 gene and antitumor effects were evaluated both in vitro and in vivo. Methods: The vaccinia virus strain Guang9 armed with IL-24 gene (VG9-IL-24) was constructed via disruption of the viral thymidine kinase (TK) gene region. The cytotoxicity of VG9-IL-24 in various breast cancer cell lines was assessed by MTT and cell cycle progression and apoptosis were examined by flow cytometry. In vivo antitumor effects were further observed in MDA-MB-231 xenograft mouse model. Results: In vitro, VG9-IL-24 efficiently infected and selectively killed breast cancer cells with no strong cytotoxicity to normal cells. VG9-IL-24 induced increased number of apoptotic cells and blocked breast cancer cells in the G2/M phase of the cell cycle. Western blotting results indicated that VG9-IL-24-mediated apoptosis was related to PI3K/β-catenin signaling pathway. In vivo, VG9-IL-24 delayed tumor growth and improved survival. Conclusions: Our findings provided documentation that VG9-IL-24 was targeted in vitro and exhibited enhanced antitumor effects, and it may be an innovative therapy for breast cancer.

Interleukin-24 Regulates T Cell Activity in Patients With Colorectal Adenocarcinoma

Interleukin (IL)-24 plays a potential anti-tumor activity in colorectal cancer in a dose-dependent manner. However, the immunoregulatory role of IL-24 to peripheral and tumor-infiltrating T cell function in colorectal cancer was not fully elucidated. In this study, twenty-nine colorectal adenocarcinoma patients and fifteen healthy individuals were enrolled. IL-24 expression and IL-24 receptor (IL-20R1, IL-20R2, and IL-22R1) mRNA relative level was measured by ELISA and real-time PCR, respectively. CD4⁺ and CD8⁺ T cells were purified from peripheral bloods and cancer specimens, and were stimulated with low (10 ng/ml) and high (100 ng/ml) concentration of recombinant IL-24. CD4⁺ T cells activity was assessed by measurement of Th cell percentage, transcriptional factors, and cytokine production. CD8⁺ T cells activity was evaluated by investigation of cytotoxic molecules, target cell death, and interferon-γ (IFN-γ) secretion. IL-24 was decreasingly expressed in both peripheral bloods and cancer tissues in colorectal adenocarcinoma patients. However, IL-20R1 and IL-20R2 was comparable between healthy controls and colorectal adenocarcinoma patients. Low concentration of IL-24 suppressed CD4⁺ T cell proliferation. In contrast, high concentration of IL-24 not only promoted CD4⁺ T cell proliferation, but also enhanced CD4⁺ T cell activity, which mainly presented as up-regulation of Th1/Th17 frequency, T-bet/RORγt mRNA, and IFN-γ/IL-17 production but down-regulation of Treg percentage, FoxP3 mRNA, and IL-10/IL-35 secretion. Moreover, high concentration of IL-24 also increased perforin and granzyme B expression in CD8⁺ T cells, and elevated cytolytic and non-cytolytic activity of CD8⁺ T cells, which presented as induction of target cell death and elevation of IFN-γ expression. However, low concentration of IL-24 did not affect bioactivity of CD8⁺ T cells. The current data indicated that IL-24 might regulate T cell function in a dose-dependent manner. High-concentration of IL-24 might promote anti-tumor immune responses in development novel therapeutic approaches to colorectal adenocarcinoma.

Tumor Cells Modified with Newcastle Disease Virus Expressing IL-24 as a Cancer Vaccine

Interleukin-24 (IL-24) is a promising agent for cancer immunotherapy that induces apoptosis of tumor cells and enhances T cell activation and function. In order to improve the antitumor activity induced by Newcastle disease virus (NDV)-modified tumor vaccine, we generated a recombinant NDV expressing IL-24 using reverse genetics. Irradiated tumor cells infected with LX/IL-24 showed stable IL-24 expression. The cytotoxicity assay showed that LX/IL-24-infected murine melanoma cells significantly enhanced the antitumor immune response in vitro. Then, the antitumor effects of virus-infected tumor cells were examined in the murine tumor models. LX/IL-24-infected tumor cells exhibited strong antitumor effects both in prophylaxis and therapeutic models. LX/IL-24-infected tumor cells increased infiltration of CD4⁺ T cells and CD8⁺ T cells in tumor sites, and the antitumor activity of the tumor vaccine modified with LX/IL-24 was dependent on CD8⁺ T cells. Taken together, our data well illustrates that LX/IL-24-modified tumor cells are a promising agent for cancer immunotherapy.

Interleukin-24 enhancing antitumor activity of chimeric oncolytic adenovirus for treating acute promyelocytic leukemia cell

BACKGROUND

Acute promyelocytic leukaemia (APL) is a clonal disease arising by hematopoietic stem cell (HSC), which characterized by inappropriate proliferation/differentiation or survival of immature myeloid progenitors. Oncolytic adenoviruses have been under widespread investigation as anticancer agents. Recently, our data suggested that tumor cells were cured by AdCN205-IL-24, an adenovirus serotype 5-based conditionally replicating adenovirus expressing IL-24 after infection.

METHODS

In this study, we created a novel fiber chimeric oncolytic adenovirus AdCN306-IL-24 that has Ad11 tropism and approved CAR (coxsackie adenovirus receptor, CAR)-independent cell entry, which could allow development of selective cytopathic effects (CPE) in APL cells in vitro.

RESULTS

Formidable cytotoxic effect was specifically implemented in APL cells after infection with AdCN306-IL-24. The expression of IL-24 was up-regulated upon treated with accepted tumors. And the vector also induced superior cytolytic effects activity in APL cells by activation of programmed cell death.

CONCLUSIONS

Taken together, our data suggested that chimeric oncolytic adenovirus AdCN306-IL-24 could express IL-24 gene, representing a potential therapeutics for acute promyelocytic leukemia.

A conditionally replicating adenovirus expressing IL-24 acts synergistically with temozolomide to enhance apoptosis in melanoma cells in vitro

Malignant melanoma is characterized by suppressed apoptosis in tumor cells and high levels of invasion. Temozolomide (TMZ) is one of the most effective single chemotherapeutic agents for patients with malignant melanoma, but resistance develops quickly and frequently. Therapeutic cytokines such as interleukin-24 (IL-24) and conditionally replicating adenoviruses have exhibited promising results as complementary therapies. Thus, the present study hypothesized that a conditionally replicating adenovirus expressing IL-24 combined with TMZ may exhibit increased antitumor activity compared with either treatment alone in melanoma A375 and M14 cell lines in vitro. The present study constructed an E1B-55 gene-deleted conditionally replicating adenovirus expressing the IL-24 gene (ZD55-IL-24). IL-24 was expressed at high levels in melanoma cells infected with ZD55-IL-24 in the presence of TMZ. The combination of ZD55-IL-24 + TMZ induced higher protein expression levels of the proapoptotic proteins B-cell lymphoma-2 (Bcl-2)-like protein 4 and phosphorylated protein, γ-H2A histone family member X (γ-H2AX), and reduced the levels of the antiapoptotic proteins Bcl-2, myeloid cell leukemia-1and nuclear factor-κB compared with either treatment individually. A dose-dependent increase in the cytopathic effects for the combination of ZD55-IL-24 and TMZ was also observed. The data of the present study suggest that the ZD55-IL-24 + TMZ combination induced increased levels of apoptosis, possibly by triggering DNA damage, in melanoma cells in vitro compared with either treatment alone. These findings suggest that this strategy may be a promising approach for the treatment of patients with malignant melanoma.

Interleukin-24 inhibits osteosarcoma cell migration and invasion via the JNK/c-Jun signaling pathways

Approximately 25% of osteosarcoma patients present with clinically detectable metastatic disease at the time of initial diagnosis. High-dose chemotherapy and/or surgery for the treatment of primary metastatic osteosarcoma is ineffective, and <20% of patients will survive 5 years from diagnosis. Therefore, the treatment of metastases is critical for the improvement of the prognosis of primary metastatic osteosarcoma patients. We have previously observed that overexpression of interleukin-24 (IL-24) inhibits neuroblastoma cell proliferation, migration and invasion in vitro. The present study investigated whether IL-24 may be a novel agent for osteosarcoma metastasis-suppressive treatment. It was observed that IL-24 is able to inhibit migration and invasion in spontaneously metastasizing human 143B osteosarcoma cells via the c-Jun N-terminal kinase (JNK)/c-Jun signaling pathway. IL-24 was effective in inhibiting JNK and c-Jun phosphorylation to downregulate matrix metalloproteinase (MMP)-2 and MMP-9, which contributed to the suppression of cell migration and invasion. It was concluded that IL-24 may be a potent agent in the inhibition of highly metastatic 143B osteosarcoma cells, and IL-24 may have translational potential as an effective therapeutic agent for the treatment of metastatic osteosarcoma.

CD47-retargeted oncolytic adenovirus armed with melanoma differentiation-associated gene-7/interleukin-24 suppresses in vivo leukemia cell growth

Our previous studies have suggested that harboring a soluble coxsackie-adenovirus receptor-ligand (sCAR-ligand) fusion protein expression cassette in the viral genome may provide a universal method to redirect oncolytic adenoviruses to various membrane receptors on cancer cells resisting to serotype 5 adenovirus infection. We report here a novel oncolytic adenovirus vector redirected to CD47+ leukemia cells though carrying a sCAR-4N1 expression cassette in the viral genome, forming Ad.4N1, in which 4N1 represents the C-terminal CD47-binding domain of thrombospondin-1. The infection and cytotoxicity of Ad.4N1 in leukemia cells were determined to be mediated by the 4N1-CD47 interaction. Ad.4N1 was further engineered to harbor a gene encoding melanoma differentiation-associated gene-7/interleukin-24 (mda-7/IL-24), forming Ad.4N1-IL24, which replicated dramatically faster than Ad.4N1, and elicited significantly enhanced antileukemia effect in vitro and in a HL60/Luc xenograft mouse model. Our data suggest that Ad.4N1 could act as a novel oncolytic adenovirus vector for CD47+ leukemia targeting gene transfer, and Ad.4N1 harboring anticancer genes may provide novel antileukemia agents.

Recent advances in delivery of drug-nucleic acid combinations for cancer treatment

Cancer treatment that uses a combination of approaches with the ability to affect multiple disease pathways has been proven highly effective in the treatment of many cancers. Combination therapy can include multiple chemotherapeutics or combinations of chemotherapeutics with other treatment modalities like surgery or radiation. However, despite the widespread clinical use of combination therapies, relatively little attention has been given to the potential of modern nanocarrier delivery methods, like liposomes, micelles, and nanoparticles, to enhance the efficacy of combination treatments. This lack of knowledge is particularly notable in the limited success of vectors for the delivery of combinations of nucleic acids with traditional small molecule drugs. The delivery of drug-nucleic acid combinations is particularly challenging due to differences in the physicochemical properties of the two types of agents. This review discusses recent advances in the development of delivery methods using combinations of small molecule drugs and nucleic acid therapeutics to treat cancer. This review primarily focuses on the rationale used for selecting appropriate drug-nucleic acid combinations as well as progress in the development of nanocarriers suitable for simultaneous delivery of drug-nucleic acid combinations.

MicroRNA-205 directly regulates the tumor suppressor, interleukin-24, in human KB oral cancer cells

MicroRNA (miRNA) is a form of small noncoding RNA that regulates the expression of genes either by inhibiting mRNA translation or by inducing its degradation. Small microRNA play important roles in regulating a large number of cellular processes, including development, proliferation and apoptosis. This study examined the biological functions of miR-205 as a tumor suppressor in KB oral cancer cells. The results showed that miR-205 expression was significantly lower in KB oral cancer cells than in human normal oral keratinocytes. Furthermore, the miR-205 over-expressed in KB oral cancer cells increased the cell cytotoxicity and induced apoptosis through the activation of caspase-3/-7. The transfection of miR-205 into KB oral cancer cells strongly induced IL-24, a well known cytokine that acts as a tumor suppressor in a range of tumor tissues. In addition, miR-205 targeted the IL-24 promoter directly to induce gene expression. Overall, miR-205 has significant therapeutic potential to turn on silenced tumor suppressor genes by targeting them with miRNA.