Role of MDA-7/IL-24 a Multifunction Protein in Human Diseases

Novel insight into MDA-7/IL-24: A potent therapeutic target for autoimmune and inflammatory diseases

Melanoma differentiation-associated gene-7 (MDA-7)/interleukin-24 (IL-24) is a pleiotropic member of the IL-10 family of cytokines, and is involved in multiple biological processes, including cell proliferation, cell differentiation, tissue fibrosis, the inflammatory response, and antitumor activity. MDA-7/IL-24 can regulate epithelial integrity, homeostasis, mucosal immunity and host resistance to various pathogens by enhancing immune and inflammatory responses. Our recent study revealed the mechanism of MDA-7/IL-24 in promoting airway inflammation and airway remodeling through activating the JAK/STAT3 and ERK signaling pathways in bronchial epithelial cells. Herein, we summarize the cellular sources, inducers, target cells, signaling pathways, and biological effects of MDA-7/IL-24 in several allergic and autoimmune diseases. This review also synopsizes recent advances in clinical research targeting MDA-7/IL-24 or its receptors. Based on these advancements, we emphasize its potential as a target for immunotherapy and discuss the challenges of developing immunotherapeutic drugs targeting MDA-7/IL-24 or its receptors in autoimmune and inflammatory disorders.

Interleukin-22 receptor 1-mediated stimulation of T-type Ca2+ channels enhances sensory neuronal excitability through the tyrosine-protein kinase Lyn-dependent PKA pathway

BACKGROUND

Interleukin 24 (IL-24) has been implicated in the nociceptive signaling. However, direct evidence and the precise molecular mechanism underlying IL-24's role in peripheral nociception remain unclear.

METHODS

Using patch clamp recording, molecular biological analysis, immunofluorescence labeling, siRNA-mediated knockdown approach and behavior tests, we elucidated the effects of IL-24 on sensory neuronal excitability and peripheral pain sensitivity mediated by T-type Ca2+ channels (T-type channels).

RESULTS

IL-24 enhances T-type channel currents (T-currents) in trigeminal ganglion (TG) neurons in a reversible and dose-dependent manner, primarily by activating the interleukin-22 receptor 1 (IL-22R1). Furthermore, we found that the IL-24-induced T-type channel response is mediated through tyrosine-protein kinase Lyn, but not its common downstream target JAK1. IL-24 application significantly activated protein kinase A; this effect was independent of cAMP and prevented by Lyn antagonism. Inhibition of PKA prevented the IL-24-induced T-current response, whereas inhibition of protein kinase C or MAPK kinases had no effect. Functionally, IL-24 increased TG neuronal excitability and enhanced pain sensitivity to mechanical stimuli in mice, both of which were suppressed by blocking T-type channels. In a trigeminal neuropathic pain model induced by chronic constriction injury of the infraorbital nerve, inhibiting IL-22R1 signaling alleviated mechanical allodynia, which was reversed by blocking T-type channels or knocking down Cav3.2.

CONCLUSION

Our findings reveal that IL-24 enhances T-currents by stimulating IL-22R1 coupled to Lyn-dependent PKA signaling, leading to TG neuronal hyperexcitability and pain hypersensitivity. Understanding the mechanism of IL-24/IL-22R1 signaling in sensory neurons may pave the way for innovative therapeutic strategies in pain management.

The role and mechanism of TXNDC5 in disease progression

Thioredoxin domain containing protein-5 (TXNDC5), also known as endothelial protein-disulfide isomerase (Endo-PDI), is confined to the endoplasmic reticulum through the structural endoplasmic reticulum retention signal (KDEL), is a member of the PDI protein family and is highly expressed in the hypoxic state. TXNDC5 can regulate the rate of disulfide bond formation, isomerization and degradation of target proteins through its function as a protein disulfide isomerase (PDI), thereby altering protein conformation, activity and improving protein stability. Several studies have shown that there is a significant correlation between TXNDC5 gene polymorphisms and genetic susceptibility to inflammatory diseases such as rheumatoid, fibrosis and tumors. In this paper, we detail the expression characteristics of TXNDC5 in a variety of diseases, summarize the mechanisms by which TXNDC5 promotes malignant disease progression, and summarize potential therapeutic strategies to target TXNDC5 for disease treatment.

A Novel Platinum Resistance-Related Immune Gene Signature for Overall Survival Prediction in Patients with Ovarian Cancer

Ovarian cancer (OV) is a highly heterogeneous gynecological tumor that makes the prognostic prediction challenging. Resistance to platinum-based chemotherapy is associated with a poor prognosis in OV. There seems to be an overlap between molecular mechanisms responsible for platinum resistance and immunogenicity in OV. However, the predictive role of platinum resistance-related immune genes for OV prognosis needs to be further explored. In our study, the mRNA expression data of OV patients with corresponding clinical information were collected from The Cancer Genome Atlas (TCGA) cohort and International Cancer Genome Consortium (ICGC) cohort. A multigene signature was constructed for OV patients in the TCGA cohort using the least absolute shrinkage and selection operator (LASSO) Cox regression model according to the optimal value of λ and was validated in the ICGC cohort. Furthermore, we performed functional analysis to explore the immune status between low- and high-risk groups based on the median value of the risk score for the multigene signature. Our data showed that there were 41.1% of the platinum resistance-related genes which differentially expressed between immune score low- and high-OV patients in the TCGA cohort. Univariate Cox regression analysis identified 30 differentially expressed genes (DEGs) associated with overall survival (OS) (P < 0.05). 14 genes were identified to construct a novel platinum resistance-related immune model for classifying OV patients into the low- and high- risk groups. Patients in the low-risk group showed significantly higher OS than those in the high-risk group (P < 0.0001 in the both TCGA and ICGC cohort), which was associated with different immune status for the two risk groups. A novel platinum resistance-related immune model can be used for prognostic prediction in OV. Targeting tumor immunity may be a therapeutic alternative for OV with platinum resistance.

Targeting PRSS23 with tipranavir induces gastric cancer stem cell apoptosis and inhibits growth of gastric cancer via the MKK3/p38 MAPK-IL24 pathway

Gastric cancer stem cells (GCSCs) contribute to the refractory features of gastric cancer (GC) and are responsible for metastasis, relapse, and drug resistance. The key factors drive GCSC function and affect the clinical outcome of GC patients remain poorly understood. PRSS23 is a novel serine protease that is significantly up-regulated in several types of cancers and cancer stem cells, and related to tumor progression and drug resistance. In this study, we investigated the role of PRSS23 in GCSCs as well as the mechanism by which PRSS23 regulated the GCSC functions. We demonstrated that PRSS23 was critical for sustaining GCSC survival. By screening a collection of human immunodeficiency virus (HIV) protease inhibitors (PIs), we identified tipranavir as a PRSS23-targeting drug, which effectively killed both GCSC and GC cell lines (its IC50 values were 4.7 and 6.4 μM in GCSC1 cells and GCSC2 cells, respectively). Administration of tipranavir (25 mg·kg-1·d-1, i.p., for 8 days) in GCSC-derived xenograft mice markedly inhibited the growth of subcutaneous GCSC tumors without apparent toxicity. In contrast, combined treatment with 5-FU plus cisplatin did not affect the tumor growth but causing significant weight loss. Furthermore, we revealed that tipranavir induced GCSC cell apoptosis by suppressing PRSS23 expression, releasing MKK3 from the PRSS23/MKK3 complex to activate p38 MAPK, and thereby activating the IL24-mediated Bax/Bak mitochondrial apoptotic pathway. In addition, tipranavir was found to kill other types of cancer cell lines and drug-resistant cell lines. Collectively, this study demonstrates that by targeting both GCSCs and GC cells, tipranavir is a promising anti-cancer drug, and the clinical development of tipranavir or other drugs specifically targeting the PRSS23/MKK3/p38MAPK-IL24 mitochondrial apoptotic pathway may offer an effective approach to combat gastric and other cancers.

Spinal interleukin-24 contributes to neuropathic pain after peripheral nerve injury through interleukin-20 receptor2 in mice

Neuroinflammation is critically involved in nerve injury-induced neuropathic pain, characterized by local and systemic increased levels of proinflammatory cytokines. Interleukin-24 (IL-24), a key member of the IL-10 family, has been extensively studied for its therapeutic potential in various diseases, including cancer, autoimmune disorders, and bacterial infections, but whether it is involved in the regulation of neuropathic pain caused by peripheral nerve injury (PNI) has not been well established. In this study, we reported that spared nerve injury (SNI) induced a significant upregulation of IL-24 in fibroblasts, neurons, and oligodendrocyte precursor cells (OPCs, also called NG2-glia) in the affected spinal dorsal horns (SDHs), as well as dorsal root ganglions (DRGs). We also found that tumor necrosis factor α (TNF-α) induced the transcriptional expression of IL-24 in cultured fibroblasts, neurons, and NG2-glia; in addition, astrocytes, microglia, and NG2-glia treated with TNF-α exhibited a prominent increase in interleukin-20 receptor 2 (IL-20R2) expression. Furthermore, we evaluated the ability of IL-24 and IL-20R2 to attenuate pain in preclinical models of neuropathic pain. Intrathecal (i.t.) injection of IL-24 neutralizing antibody or IL-20R2 neutralizing antibody could effectively alleviate mechanical allodynia and thermal hyperalgesia after PNI. Similarly, intrathecal injection of IL-24 siRNA or IL-20R2 siRNA also alleviated mechanical allodynia after SNI. The inhibition of IL-24 reduced SNI-induced proinflammatory cytokine (IL-1β and TNF-α) production and increased anti-inflammatory cytokine (IL-10) production. Meanwhile, the inhibition of IL-20R2 also decreased IL-1β mRNA expression after SNI. Collectively, our findings revealed that IL-24/IL-20R might contribute to neuropathic pain through inflammatory response. Therefore, targeting IL-24 could be a promising strategy for treating neuropathic pain induced by PNI.

The investigation of the death-inducing potency of a recombinant Adenovector expressing Mda-7-tlyp-1 on different cancer cell lines

Aim

The potency of Adenovector expressing Mda7-tLyp1 (Ad-Mda7-tLyp1) for death induction was evaluated on the breast (MCF7), liver (HepG2), and gastric (MKN45) cancer cell lines.

Background

Mda-7 could be a possible complementary to traditional cancer therapy, and tethering to tumor-homing peptides (THPs) might improve its therapeutic efficacy.

Methods

After the preparation of recombinant Ad-Mda7-tLyp1 and Ad-Mda7, the expression of recombinant proteins was analyzed by ELISA. Adenovectors were transduced (MOI=2-5) into Hep-G2, MCF7, MKN45, and normal skin fibroblast, then tumor-killing effect was measured by cytopathic effect (CPE) monitoring, MTT viability test, BAX gene expression analysis, and Caspase3/7 assay.

Results

ELISA assay revealed a sustained level of recombinant protein secretion following Adenovector transduction. In CPE microscopy, all cancer cell lines showed a significant reduction (≥50%) in their normal phenotype after receiving Ad-Mda7-tLyp1 and Ad-Mda7. The viability was significantly lower compared to the control, indicating an anti-proliferating effect. In parallel, the viability test showed that Ad-Mda7 and Ad-Mda7-tLyp1 have a significant killing effect (≥50%) on MCF-7, Hep-G2, and MKN45 compared to normal fibroblast (P≤0.05). BAX gene expression analysis showed that both Ad-Mda7-tLyp1 and Ad-Mda7 vectors induced >2-fold increase of apoptosis (P<0.05), particularly in MCF7. Similarly, caspase3/7 activity showed a significant increase (P<0.05) following Ad-Mda7, and Ad-Mda7-tLyp1 transduction into cancer cell lines, but not in normal fibroblasts.

Conclusion

The newly constructed Ad-Mda-tlyp1 showed a suitable tumor cell killing activity and enough specificity on studied cell lines.

GSK-3α aggravates inflammation, metabolic derangement, and cardiac injury post-ischemia/reperfusion

Reperfusion after acute myocardial infarction further exaggerates cardiac injury and adverse remodeling. Irrespective of cardiac cell types, loss of specifically the α isoform of the protein kinase GSK-3 is protective in chronic cardiac diseases. However, the role of GSK-3α in clinically relevant ischemia/reperfusion (I/R)-induced cardiac injury is unknown. Here, we challenged cardiomyocyte-specific conditional GSK-3α knockout (cKO) and littermate control mice with I/R injury and investigated the underlying molecular mechanism using an in vitro GSK-3α gain-of-function model in AC16 cardiomyocytes post-hypoxia/reoxygenation (H/R). Analysis revealed a significantly lower percentage of infarct area in the cKO vs. control hearts post-I/R. Consistent with in vivo findings, GSK-3α overexpression promoted AC16 cardiomyocyte death post-H/R which was accompanied by an induction of reactive oxygen species (ROS) generation. Consistently, GSK-3α gain-of-function caused mitochondrial dysfunction by significantly suppressing mitochondrial membrane potential. Transcriptomic analysis of GSK-3α overexpressing cardiomyocytes challenged with hypoxia or H/R revealed that NOD-like receptor (NLR), TNF, NF-κB, IL-17, and mitogen-activated protein kinase (MAPK) signaling pathways were among the most upregulated pathways. Glutathione and fatty acid metabolism were among the top downregulated pathways post-H/R. Together, these observations suggest that loss of cardiomyocyte-GSK-3α attenuates cardiac injury post-I/R potentially through limiting the myocardial inflammation, mitochondrial dysfunction, and metabolic derangement. Therefore, selective inhibition of GSK-3α may provide beneficial effects in I/R-induced cardiac injury and remodeling. KEY MESSAGES: GSK-3α promotes cardiac injury post-ischemia/reperfusion (I/R). GSK-3α regulates inflammatory and metabolic pathways post-hypoxia/reoxygenation (H/R). GSK-3α overexpression upregulates NOD-like receptor (NLR), TNF, NF-kB, IL-17, and MAPK signaling pathways in cardiomyocytes post-H/R. GSK-3α downregulates glutathione and fatty acid metabolic pathways in cardiomyocytes post-H/R.

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.

Molecular mechanism of anti-inflammatory effects of the proteasome inhibitor MG-132 on Con A-induced acute liver injury in mice

MG-132, an aldehyde-based peptide proteasome inhibitor (PI) that binds to the proteasome and reversibly inhibits proteasome activity, has been widely used in experimental research. However, it is not clear whether MG-132 has anti-inflammatory effects on liver injury. The molecular mechanism of the anti-inflammatory effect of the PI MG-132 on Con A-induced acute liver injury (ALI) mice was investigated by ELISA, HE, q RT-PCR, and IHC. The results showed that the serum activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and TNF-α and IL-6 contents of mice in the high and medium dose groups were reduced compared with those in the ALI group. The superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels in liver tissues were significantly increased, and the malondialdehyde (MDA) content was decreased. The pathological sections of mice in the ALI group showed typical ALI manifestations such as significant central venous stasis of liver tissues, cell swelling, and inflammatory cell infiltration. The pathological damage of liver tissues was relieved significantly in the three dose groups, especially in the high-dose group. The transcriptional level of TLR4/NF-κB pathway key factors mRNA was significantly reduced, and the expression of TLR4 and NF-κB P65 protein in liver tissues was significantly and positively correlated with the contents of TNF-α and IL-1β (p < 0.01). Our findings suggest that MG-132 can alleviate the inflammatory response to Con A-induced ALI and exert a hepatoprotective effect, and its anti-inflammatory effect is related to the inhibition of TLR4/NF-κB signaling pathway activation.

Interleukin 24 promotes cell death in renal epithelial cells and is associated with acute renal injury

Ischemia-reperfusion injury is a major cause of acute kidney injury. Many cytokines are involved in the pathogenesis of renal ischemia-reperfusion injury. IL24 is a member of the IL10 family and has gained importance because of its apoptosis-inducing effects in tumor disease besides its immunoregulative function. Littles is known about the role of IL24 in kidney disease. Using a mouse model, we found that IL24 is upregulated in the kidney after renal ischemia-reperfusion injury and that tubular epithelial cells and infiltrating inflammatory cells are the source of IL24. Mice lacking IL24 are protected from renal injury and inflammation. Cell culture studies showed that IL24 induces apoptosis in renal tubular epithelial cells, which is accompanied by an increased endoplasmatic reticulum stress response. Moreover, IL24 induces robust expression of endogenous IL24 in tubular cells, fostering ER-stress and apoptosis. In kidney transplant recipients with delayed graft function and patients at high risk to develop acute kidney injury after cardiac surgery IL24 is upregulated in the kidney and serum. Taken together, IL24 can serve as a biomarker, plays an important mechanistic role involving both extracellular and intracellular targets, and is a promising therapeutic target in patients at risk of or with ischemia-induced acute kidney injury.

Enhanced synergistic antitumor effect of a DNA vaccine with anticancer cytokine, MDA-7/IL-24, and immune checkpoint blockade

Background

MDA-7/IL-24 cytokine has shown potent antitumor properties in various types of cancer without exerting any significant toxicity on healthy cells. It has also been proved to encompass pro-immune Th1 cytokine-like behavior. Several E7 DNA vaccines have developed against human papillomavirus (HPV)-related cervical cancer. However, the restricted immunogenicity has limited their clinical applications individually. To address this deficiency, we investigated whether combining the E7 DNA vaccine with MDA-7/IL-24 as an adjuvant would elicit efficient antitumor responses in tumor-bearing mouse models. Next, we evaluated how suppression of immunosuppressive IL-10 cytokine would enhance the outcome of our candidate adjuvant vaccine.

Methods

For this purpose, tumor-bearing mice received either E7 DNA vaccine, MDA-7/IL-24 cytokine or combination of E7 vaccine with MDA-7/IL-24 adjuvant one week after tumor challenge and boosted two times with one-week interval. IL-10 blockade was performed by injection of anti-IL-10 mAb before each immunization. One week after the last immunization, mice were sacrificed and the treatment efficacy was evaluated through immunological and immunohistochemical analysis. Moreover, the condition of tumors was monitored every two days for six weeks intervals from week 2 on, and the tumor volume was measured and compared within different groups.

Results

A highly significant synergistic relationship was observed between the E7 DNA vaccine and the MDA-7/IL-24 cytokine against HPV-16+ cervical cancer models. An increase in proliferation of lymphocytes, cytotoxicity of CD8+ T cells, the level of Th1 cytokines (IFN-γ, TNF-α) and IL-4, the level of apoptotic markers (TRAIL and caspase-9), and a decrease in the level of immunosuppressive IL-10 cytokine, together with the control of tumor growth and the induction of tumor regression, all prove the efficacy of adjuvant E7&IL-24 vaccine when compared to their individual administration. Surprisingly, vaccination with the DNA E7&IL-24 significantly reduced the population of Regulatory T cells (Treg) in the spleen of immunized mice compared to sole administration and control groups. Moreover, IL-10 blockade enhanced the effect of the co-administration by eliciting higher levels of IFN-γ and caspase-9, reducing Il-10 secretion and provoking the regression of tumor size.

Conclusion

The synergy between the E7 DNA vaccine and MDA-7/IL-24 suggests that DNA vaccines’ low immunogenicity can be effectively addressed by coupling them with an immunoregulatory agent. Moreover, IL-10 blockade can be considered a complementary treatment to improve the outcome of conventional or novel cancer therapies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12985-022-01842-x.

Enhanced Cancer Therapy Using an Engineered Designer Cytokine Alone and in Combination With an Immune Checkpoint Inhibitor

melanoma differentiation associated gene-7 or Interleukin-24 (mda-7, IL-24) displays expansive anti-tumor activity without harming corresponding normal cells/tissues. This anticancer activity has been documented in vitro and in vivo in multiple preclinical animal models, as well as in patients with advanced cancers in a phase I clinical trial. To enhance the therapeutic efficacy of MDA-7 (IL-24), we engineered a designer cytokine (a "Superkine"; IL-24S; referred to as M7S) with enhanced secretion and increased stability to engender improved "bystander" antitumor effects. M7S was engineered in a two-step process by first replacing the endogenous secretory motif with an alternate secretory motif to boost secretion. Among four different signaling peptides, the insulin secretory motif significantly enhanced the secretion of MDA-7 (IL-24) protein and was chosen for M7S. The second modification engineered in M7S was designed to enhance the stability of MDA-7 (IL-24), which was accomplished by replacing lysine at position K122 with arginine. This engineered "M7S Superkine" with increased secretion and stability retained cancer specificity. Compared to parental MDA-7 (IL-24), M7S (IL-24S) was superior in promoting anti-tumor and bystander effects leading to improved outcomes in multiple cancer xenograft models. Additionally, combinatorial therapy using MDA-7 (IL-24) or M7S (IL-24S) with an immune checkpoint inhibitor, anti-PD-L1, dramatically reduced tumor progression in murine B16 melanoma cells. These results portend that M7S (IL-24S) promotes the re-emergence of an immunosuppressive tumor microenvironment, providing a solid rationale for prospective translational applications of this therapeutic designer cytokine.

Oncolytic therapy with vaccinia virus carrying IL-24 for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a highly refractory cancer associated with increasing mortality, which currently lacks effective treatment options. Interleukin-24 (IL-24) is a novel tumor suppressor cytokine that can selectively induce cancer cell apoptosis, and it has been utilized as a cancer gene therapy strategy. The vaccinia virus is a promising strategy for cancer therapy, owing to its direct viral lytic effects, as well as a vehicle to overexpress therapeutic transgenes.

METHODS

We constructed a recombinant oncolytic vaccinia viruse (VG9-IL-24) based on vaccinia virus Guang9 (VG9) harboring the IL-24 gene. In vitro, we assessed the replication of VG9-IL-24 in HCC cell lines and normal liver cells and evaluated the cytotoxicity in different cell lines; then, we determined the expression of IL-24 by RT-PCR and ELISA. We examined apoptosis and cell cycle progression in SMMC-7721 cells treated with VG9-IL-24 by flow cytometry. In vivo, we established the SMMC-7721 xenograft mouse model to evaluate the antitumor effects of VG9-IL-24.

RESULTS

In vitro, VG9-IL-24 efficiently infected HCC cell lines, but not normal liver cells, and resulted in a high level of IL-24 expression and significant cytotoxicity. Moreover, VG9-IL-24 induced an increase in the proportion of apoptotic cells and blocked the SMMC-7721 cell cycle in the G2/M phase. In vivo, tumor growth was significantly suppressed and the survival was prolonged in VG9-IL-24-treated mice.

CONCLUSIONS

Vaccinia virus VG9-mediated gene therapy might be an innovative treatment for cancer with tumor-specific lysis and apoptosis-inducing effects. VG9-IL-24 exhibited enhanced antitumor effects and is a promising candidate for HCC therapy.

Insights into the Mechanisms of Action of MDA-7/IL-24: A Ubiquitous Cancer-Suppressing Protein

Melanoma differentiation associated gene-7/interleukin-24 (MDA-7/IL-24), a secreted protein of the IL-10 family, was first identified more than two decades ago as a novel gene differentially expressed in terminally differentiating human metastatic melanoma cells. MDA-7/IL-24 functions as a potent tumor suppressor exerting a diverse array of functions including the inhibition of tumor growth, invasion, angiogenesis, and metastasis, and induction of potent "bystander" antitumor activity and synergy with conventional cancer therapeutics. MDA-7/IL-24 induces cancer-specific cell death through apoptosis or toxic autophagy, which was initially established in vitro and in preclinical animal models in vivo and later in a Phase I clinical trial in patients with advanced cancers. This review summarizes the history and our current understanding of the molecular/biological mechanisms of MDA-7/IL-24 action rendering it a potent cancer suppressor.

The clinical significance of interleukin 24 and its potential molecular mechanism in laryngeal squamous cell carcinoma

Interleukin 24 (IL24) has been documented to be highly expressed in several cancers, but its role in laryngeal squamous cell carcinoma (LSCC) remains unclarified. In this study, to reveal the function and its clinical significance of IL24 in LSCC, multiple detecting methods were used comprehensively. IL24 protein expression was remarkably higher in LSCC (n= 49) than non-cancerous laryngeal controls (n= 26) as detected by in-house immunohistochemistry. Meanwhile, the IL24 mRNA expression was also evaluated based on high throughput data from Gene Expression Omnibus, The Cancer Genome Atlas, ArrayExpress and Oncomine databases. Consistently with the protein level, IL24 mRNA expression level was also predominantly upregulated in LSCC (n= 172) compared to non-cancerous laryngeal tissues (n= 81) with the standard mean difference (SMD) being 1.25 and the area under the curve (AUC) of the summary receiver operating characteristic (sROC) being 0.89 (95% CI = 0.86-0.92). Furthermore, the related genes of IL24 and the differentially expressed genes (DEGs) of LSCC were intersected and sent for Gene ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and the protein-protein interaction (PPI) analyses. In the GO annotation, the top terms of biological process (BP), cellular component (CC) and molecular function (MF) were extracellular matrix organization, extracellular matrix, cytokine activity, respectively. The top pathway of KEGG was ECM-receptor interaction. The PPI networks indicated the top hub genes of IL24-related genes in LSCC were SERPINE1, TGFB1, MMP1, MMP3, CSF2, and ITGA5. In conclusion, upregulating expression of IL24 may enhance the occurrence of LSCC, which owns prospect diagnostic ability and therapeutic significance in LSCC.

The Pathogenesis of Chronic Spontaneous Urticaria: The Role of Infiltrating Cells

Chronic spontaneous urticaria is characterized by a perivascular non-necrotizing cellular infiltrate around small venules of the skin. It consists primarily of CD4(+) lymphocytes, a prominence of the T helper (Th)2 subtype but also Th1 cells, with Th17 cell-derived cytokines elevated in plasma. There are also neutrophils, eosinophils, basophils, and monocytes. Chemokines derived from mast cells and activated endothelial cells drive the process. Although the role of the cellular infiltrate has not previously been addressed, each constituent can contribute to the overall pathogenesis. It is of interest that CSU responds to corticosteroid, yet, short-term steroids do not affect autoimmunity or degranulation of mast cells, and act on margination of cells along the endothelium and chemotaxis to enter the surrounding dermis. In this review, we address each cell's contribution to the overall inflammatory response, as it is currently understood, with a view toward development of therapeutic options that impede the function of critical cells and/or their secretory products.

Engineering T Cells to Express Tumoricidal MDA-7/IL24 Enhances Cancer Immunotherapy

Antigen-specific immunotherapy can be limited by induced tumor immunoediting (e.g., antigen loss) or through failure to recognize antigen-negative tumor clones. Melanoma differentiation-associated gene-7/IL24 (MDA-7/IL24) has profound tumor-specific cytotoxic effects in a broad spectrum of cancers. Here we report the enhanced therapeutic impact of genetically engineering mouse tumor-reactive or antigen-specific T cells to produce human MDA-7/IL24. While mock-transduced T cells only killed antigen-expressing tumor cells, MDA-7/IL24-producing T cells destroyed both antigen-positive and negative cancer targets. MDA-7/IL24-expressing T cells were superior to their mock-engineered counterparts in suppressing mouse prostate cancer and melanoma growth as well as metastasis. This enhanced antitumor potency correlated with increased tumor infiltration and expansion of antigen-specific T cells as well as induction of a Th1-skewed immunostimulatory tumor environment. MDA-7/IL24-potentiated T-cell expansion was dependent on T-cell-intrinsic STAT3 signaling. Finally, MDA-7/IL24-modified T-cell therapy significantly inhibited progression of spontaneous prostate cancers in Hi-Myc transgenic mice. Taken together, arming T cells with tumoricidal and immune-potentiating MDA-7/IL24 confers new capabilities of eradicating antigen-negative cancer cell clones and improving T-cell expansion within tumors. This promising approach may be used to optimize cellular immunotherapy for treating heterogeneous solid cancers and provides a mechanism for inhibiting tumor escape. SIGNIFICANCE: This research describes a novel strategy to overcome the antigenic heterogeneity of solid cancers and prevent tumor escape by engineering T lymphocytes to produce a broad-spectrum tumoricidal agent.

The role of interleukin-10 family members in cardiovascular diseases

Interleukin (IL)-10 cytokine family members, including IL-10, IL-19, IL-20, IL-22, IL-24, IL-26 and the distantly related IL-28A, IL-28B, and IL-29, play critical roles in the regulation of inflammation. The occurrence and progression of cardiovascular diseases closely correlate with the regulation of inflammation, which may provide novel strategies for the treatment of cardiovascular diseases. In recent years, studies have focused on the association between the IL-10 cytokine family and the physiological and pathological progression of cardiovascular diseases. The aim of this review is to summarize relevant studies and clarify whether the IL-10 cytokine family contributes to the regulation of cardiovascular diseases.

Luteolin enhances the antitumor efficacy of oncolytic vaccinia virus that harbors IL-24 gene in liver cancer cells

BACKGROUND

Interleukin 24 (IL-24) is an IL-10 family member and a secreted cytokine characterized by cancer-targeted toxicity and can activate apoptosis by sensitizing cancer cells to chemotherapy. Cytotoxic effects of luteolin on different types of cancer cells suppress their growth by acting on the components of the apoptosis signaling cascade. Therefore, our study aimed to prove whether oncolytic vaccinia virus (VV) that harbors IL-24 (VV-IL-24) combine with luteolin exerts a synergistic inhibitory effect in liver cancer cells.

METHODS

Impacts on cell viability of VV-IL-24 and luteolin were assessed by MTT in various liver cancer cell lines. Then, liver cancer cell apoptosis was analyzed via flow cytometry and Western blotting. Besides, the MHCC97-H xenograft mouse model was employed as a means of assessing in vivo antitumor efficacy.

RESULTS

MTT assay confirmed that the combination treatment decreased liver cancer cells viability to a greater degree than treatment with VV-IL-24 or luteolin alone. Flow cytometry and Western blot assay proved that VV-IL-24 plus luteolin induced more liver cancer cells apoptosis than single treatment. Furthermore, in the MHCC97-H xenograft model, 15 days of treatment with VV-IL-24 plus luteolin inhibited tumor growth significantly more than single treatment.

CONCLUSION

These data confirm that the synergistic mechanism of VV-IL-24 and luteolin elicits a stronger tumor growth inhibition than any single therapy. Thus, the combination of VV-IL-24 and luteolin could provide the basis for preclinical research in the treatment of liver cancer.

MDA-9/Syntenin/SDCBP: new insights into a unique multifunctional scaffold protein

Tumor metastasis comprises a series of coordinated events that culminate in dissemination of cancer cells to distant sites within the body representing the greatest challenge impeding effective therapy of cancer and the leading cause of cancer-associated morbidity. Cancer cells exploit multiple genes and pathways to colonize to distant organs. These pathways are integrated and regulated at different levels by cellular- and extracellular-associated factors. Defining the genes and pathways that govern metastasis can provide new targets for therapeutic intervention. Melanoma differentiation associated gene-9 (mda-9) (also known as Syntenin-1 and SDCBP (Syndecan binding protein)) was identified by subtraction hybridization as a novel gene displaying differential temporal expression during differentiation of melanoma. MDA-9/Syntenin is an established Syndecan binding protein that functions as an adaptor protein. Expression of MDA-9/Syntenin is elevated at an RNA and protein level in a wide-range of cancers including melanoma, glioblastoma, neuroblastoma, and prostate, breast and liver cancer. Expression is increased significantly in metastatic cancer cells as compared with non-metastatic cancer cells or normal cells, which make it an attractive target in treating cancer metastasis. In this review, we focus on the role and regulation of mda-9 in cancer progression and metastasis.

Aberrant expression of USF2 in refractory rheumatoid arthritis and its regulation of proinflammatory cytokines in Th17 cells

IL-17-producing Th17 cells are implicated in the pathogenesis of rheumatoid arthritis (RA) and TNF-α, a proinflammatory cytokine in the rheumatoid joint, facilitates Th17 differentiation. Anti-TNF therapy ameliorates disease in many patients with rheumatoid arthritis (RA). However, a significant proportion of patients do not respond to this therapy. The impact of anti-TNF therapy on Th17 responses in RA is not well understood. We conducted high-throughput gene expression analysis of Th17-enriched CCR6+CXCR3-CD45RA- CD4+ T (CCR6+ T) cells isolated from anti-TNF-treated RA patients classified as responders or nonresponders to therapy. CCR6+ T cells from responders and nonresponders had distinct gene expression profiles. Proinflammatory signaling was elevated in the CCR6+ T cells of nonresponders, and pathogenic Th17 signature genes were up-regulated in these cells. Gene set enrichment analysis on these signature genes identified transcription factor USF2 as their upstream regulator, which was also increased in nonresponders. Importantly, short hairpin RNA targeting USF2 in pathogenic Th17 cells led to reduced expression of proinflammatory cytokines IL-17A, IFN-γ, IL-22, and granulocyte-macrophage colony-stimulating factor (GM-CSF) as well as transcription factor T-bet. Together, our results revealed inadequate suppression of Th17 responses by anti-TNF in nonresponders, and direct targeting of the USF2-signaling pathway may be a potential therapeutic approach in the anti-TNF refractory RA.

SUMO-fusion and autoinduction-based combinatorial approach for enhanced production of bioactive human interleukin-24 in Escherichia coli

High-level production of recombinant human interleukin-24 (IL-24), a multifunctional immunomodulatory cytokine, has been challenging due primarily to its aggregation as inclusion bodies in the bacterial host while persistent poor-expression in the insect/mammalian expression systems. The present study presents a robust, vector-host combination (pE-SUMO-IL24), auto-inducible medium (YNG/M9NG), and a simple purification scheme for soluble, bioactive, and cost-effective production of native-like IL-24 (nIL-24) in Escherichia coli. The final protein yield, following a three-step purification scheme (IMAC, SEC, dialysis), was 98 mg/L in shake-flask culture (with scale-up potential), which was several folds higher than reported earlier. In vitro cytotoxicity assays with HeLa and HCT116 cancer cell lines (performed using different concentrations of nIL-24) and the fluorescence activated cell sorting analysis (FACS) revealed a dose- and concentration-dependent increase in the population of pro-apoptotic cells with concomitant, statistically significant drop in the number of cells existent at G_o/G1-, S-, and G2/M-phases (P < 0.002). The bioactive nIL-24, developed through this study, holds promise for use in further functional characterizations/applications. KEY POINTS: • Yeast SUMO fusion partner at N-terminus for improved solubility of an otherwise insoluble IL-24 in E. coli. • Enhanced cell densities with concomitant several-fold increase in protein yield by lactose-inducible media. • Improved inhibition of cervical and colorectal carcinomas by native-like nIL-24 compared with Met-containing IL. • Heterologous nIL-24 may enable better understanding of the functional intricacies linked up with its unique cancer-specific features. Graphical abstract.

Clinical Significance of the Interleukin 24 mRNA Level in Head and Neck Squamous Cell Carcinoma and Its Subgroups: An In Silico Investigation

IL24 mRNA is known to have an apoptotic effect on cancer cells but not on noncancer cells. However, the expression level of the IL24 mRNA in head and neck squamous cell carcinoma (HNSCC) and its subgroups is rarely studied. In this study, the clinical implication of IL24 mRNA was evaluated in the common subgroups of HNSCC, including oral squamous cell carcinoma (OSCC), nasopharyngeal carcinoma (NPC), and laryngeal squamous cell carcinoma (LSCC) for analysis. Substantial IL24 mRNA expression data were calculated from several databases, such as the Gene Expression Omnibus (GEO), ArrayExpress, Sequence Read Archive (SRA), ONCOMINE, and The Cancer Genome Atlas (TCGA) databases. We ultimately collected a total of 41 microarrays and RNA-seq including 1,564 HNSCC and 603 noncancer tissue samples. IL24 mRNA was highly expressed in OSCC, LSCC, and NPC as shown by the separated standard mean difference (SMD), as well as HNSCC as a whole part (SMD = 1.47, 95% confdence interval (CI) = 1.24−1.70, P < 0.0001). In all subgroups, the IL24 mRNA upregulation had the ability to distinguish cancer from noncancer tissue with area under the curves (AUCs) of the summary receiver operating characteristic (sROC) higher than 0.85. In conclusion, IL24 mRNA may be used as a potential marker for cancer screening, and its clinical diagnostic value needs to be further studied. It also provides a new idea for the treatment of the IL24 gene in HNSCC and its subgroups in the future.

IL-24: A new player in the pathogenesis of pro-inflammatory and allergic skin diseases

Interleukin (IL)-24 is a member of the IL-20 family of cytokines and is produced by various types of cells, such as CD4⁺ T cells, NK cells, mast cells, keratinocytes, bronchial epithelial cells, and myofibroblasts. Previous studies suggest that IL-24 plays an essential role in the pathogenesis of pro-inflammatory autoimmune disorders such as psoriasis, arthritis, and inflammatory bowel diseases. However, the role of IL-24 in the pathogenesis of allergic diseases has been elusive. It has already been reported that IL-24 is involved in the pathogenesis of allergic lung and skin diseases. Moreover, we have recently revealed for the first time the pivotal functions of IL-24 in IL-13-mediated skin barrier dysfunction in atopic dermatitis (AD), which is known to be a characteristic of AD caused by Th2 cytokines such as IL-4 or IL-13. In this review, we show recent advances in the basic characteristics of IL-24 and its novel functions in the pathogenesis of allergic skin inflammation, focusing on AD. A better understanding of the role of IL-24 in allergic diseases can lead to the development of new therapeutic options.

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.

Interleukin-24 is a novel diagnostic biomarker for the severity of acute kidney injury

There is a clinical need for sensitive acute kidney injury (AKI) biomarkers that enable early therapeutic interventions and prediction of disease prognosis. In this study, we monitored interleukin (IL)-24 expressed in kidneys with severe AKI that progresses to atrophic kidney in a mouse model of ischemia-reperfusion injury (IRI). Therefore, we evaluated IL-24 as a potential biomarker not only for early diagnosis of AKI, but also for predicting progression to chronic kidney disease (CKD). Serum IL-24 was detected earlier than the elevation of serum creatinine levels and urinary IL-24 was detected as early as neutrophil gelatinase associated lipocalin (NGAL) in severe AKI (60 min of IRI). In addition, serum and urine IL-24 levels tended to increase in relation to ischemia duration. In such kidneys, vascular smooth muscle cells expressed IL-24 in response to the injury in the renal tubular epithelial cell and its target was the renal tubular epithelial cell itself. IL-24 may play a pivotal role in the communication between tubular epithelial cells and vascular smooth muscle cells and, in conclusion, IL-24 can be used as a sensitive biomarker for AKI.

Inhibition of NR4A1 Promotes ROS Accumulation and IL24-Dependent Growth Arrest in Rhabdomyosarcoma

Nuclear receptor 4A1 (NR4A1, Nur77) is overexpressed in rhabdomyosarcoma (RMS), and inactivation of NR4A1 (siNR4A1) or treatment with the NR4A1 antagonist 1,1-bis(3'-indoly)-1-(p-hydroxy-phenyl)methane (DIM-C-pPhOH) has antiproliferative and proapoptotic effects on RMS cells. However, the mechanism by which NR4A1 inhibition exerts these effects is poorly defined. Here, we report that NR4A1 silencing or inhibition resulted in accumulation of reactive oxygen species (ROS) and ROS-dependent induction of the tumor suppressor-like cytokine IL24 in RMS cells. Mechanistically, NR4A1 was found to regulate the expression of the proreductant genes thioredoxin domain-containing 5 (TXNDC5) and isocitrate dehydrogenase 1 (IDH1), which are downregulated in RMS cells following NR4A1 knockdown or inhibition. Silencing TXNDC5 and IDH1 also induced ROS accumulation and IL24 expression in RMS cells, suggesting that NR4A1 antagonists mediate their antiproliferative and apoptotic effects through modulation of proreductant gene expression. Finally, cotreatment with the antioxidant glutathione or IL24-blocking antibody reversed the effects of NR4A1 inhibition, demonstrating the importance of both ROS and IL24 in mediating the cellular responses. IMPLICATIONS: Overall, these data elucidate the mechanism by which NR4A1 inhibition functions to inhibit the proliferation, survival, and migration of RMS cells.

Mechanism of internalization of MDA-7/IL-24 protein and its cognate receptors following ligand-receptor docking

Melanoma differentiation associated gene-7 (mda-7/IL-24) is a member of the IL-10 family of cytokines, with ubiquitous direct and "bystander" tumor-selective killing properties. MDA-7/IL-24 protein binds distinct type II cytokine heterodimeric receptor complexes, IL-20R1/IL-20R2, IL-22R1/IL-20R1 and IL-22R1/IL-20R2. Recombinant MDA-7/IL-24 protein induces endogenous mda-7/IL-24 expression in a receptor-dependent manner; since A549 cells that lack a complete set of cognate receptors are not responsive to exogenous protein. The mechanism of MDA-7/IL-24 ligand-receptor biology is not well understood. We explored the interaction of MDA-7/IL-24 with its' receptors and the consequences of ligand-receptor docking. Using both pharmacological and genetic approaches we demonstrate that MDA-7/IL-24 internalization employs the clathrin-mediated endocytic pathway leading to degradation of receptors via the lysosomal/ubiquitin proteosomal pathway. This clathrin-mediated endocytosis is dynamin-dependent. This study resolves a novel mechanism of MDA-7/IL-24 protein "bystander" function, which involves receptor/protein-mediated internalization and receptor degradation.

Recent insights into apoptosis and toxic autophagy: The roles of MDA-7/IL-24, a multidimensional anti-cancer therapeutic

Apoptosis and autophagy play seminal roles in maintaining organ homeostasis. Apoptosis represents canonical type I programmed cell death. Autophagy is viewed as pro-survival, however, excessive autophagy can promote type II cell death. Defective regulation of these two obligatory cellular pathways is linked to various diseases, including cancer. Biologic or chemotherapeutic agents, which can reprogram cancer cells to undergo apoptosis- or toxic autophagy-mediated cell death, are considered effective tools for treating cancer. Melanoma differentiation associated gene-7 (mda-7) selectively promotes these effects in cancer cells. mda-7 was identified more than two decades ago by subtraction hybridization showing elevated expression during induction of terminal differentiation of metastatic melanoma cells following treatment with recombinant fibroblast interferon and mezerein (a PKC activating agent). MDA-7 was classified as a member of the IL-10 gene family based on its chromosomal location, and the presence of an IL-10 signature motif and a secretory sequence, and re-named interleukin-24 (MDA-7/IL-24). Multiple studies have established MDA-7/IL-24 as a potent anti-cancer agent, which when administered at supra-physiological levels induces growth arrest and cell death through apoptosis and toxic autophagy in a wide variety of tumor cell types, but not in corresponding normal/non-transformed cells. Furthermore, in a phase I/II clinical trial, MDA-7/IL-24 administered by means of a non-replicating adenovirus was well tolerated and displayed significant clinical activity in patients with multiple advanced cancers. This review examines our current comprehension of the role of MDA-7/IL-24 in mediating cancer-specific cell death via apoptosis and toxic autophagy.

Effects of melanoma differentiation associated gene-7 (MDA-7/IL-24) on apoptosis of liver cancer cells via regulating the expression of B-cell lymphoma-2

The present study investigated the mechanism of selective killing of liver cancer cells of melanoma differentiation associated gene-7 (MDA-7, also called IL-24α) in order to provide a theoretical basis for gene therapy of liver cancer. A recombinant eukaryotic expression vector (pcDNA3-MDA-7) containing human MDA-7 gene was constructed, which was then delivered to liver cancer cell line HepG2 and normal liver cell line L02. The positive cell clone was screened by G418. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was performed to confirm the occurrence of MDA-7 transcription in the transfected cells. The protein expression of MDA-7 was determined by western blot analysis. The effects of MDA-7 on liver cancer cell proliferation and apoptosis were investigated through MTT assay and flow cytometry by Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double-staining. The mitochondrial protein was extracted from the normal liver cell line L02 and liver cancer cell line HepG2 at 3 day post-culture, in which the alterations of anti-apoptotic B-cell lymphoma-2 (Bcl-2), pro-apoptotic Bcl-2 associated X protein (Bax), mitochondria-released cytochrome c and caspase 9 were determined by western blot analysis. pcDNA3-MDA-7 mediated the expression of foreign gene MDA-7 in HepG2 and L02 cells. MDA-7 promoted liver cancer cell apoptosis and inhibited cell proliferation; while no effect was exerted on normal liver cells, as determined by the MTT assay and flow cytometry. Relative to the L02 cells, the protein expression of Bcl-2 was downregulated in the HepG2 cells, while that of Bax, cytochrome c and caspase 9 were upregulated. In the study, the eukaryotic expression vector pcDNA3-MDA-7 was successfully constructed, it can mediate the expression of MDA-7 in human liver cancer cells and normal liver cells and inhibits the proliferation of human liver cancer cells through the restored expression of mitochondrial pro-apoptotic Bcl-2.

Elevated levels of IL-24 in systemic lupus erythematosus patients

OBJECTIVE

This study aimed to assess IL-24 levels and their association with clinical manifestations in patients with systemic lupus erythematosus (SLE).

METHODS

There were 75 patients with SLE and 58 healthy controls recruited in this study. Serum levels of IL-24 were measured by enzyme-linked immunosorbent assays, and mRNA levels of IL-24 were tested by quantitative real-time polymerase chain reaction . The area under the curve of the receiver operating characteristic (ROC) curve was used for diagnostic ability of the inflammatory cytokine.

RESULTS

Serum IL-24 levels were significantly higher in SLE patients than that in healthy controls. SLE patients with nephritis had higher IL-24 levels than those without nephritis. Active SLE patients showed higher expression of IL-24 as compared to less active disease patients. The mRNA levels of IL-24 were much higher in SLE patients. Correlation analysis showed significant correlation between serum IL-24 levels and SLE disease activity index. In addition, ROC analysis may suggest good ability of serum IL-24 in differentiating SLE.

CONCLUSION

The inflammatory cytokine correlated with SLE disease activity, and may be involved in this disease pathogenesis.

MDA-7/IL-24 regulates the miRNA processing enzyme DICER through downregulation of MITF

Melanoma differentiation-associated gene-7/interleukin-24 (mda-7/IL-24) is a multifunctional cytokine displaying broad-spectrum anticancer activity in vitro or in vivo in preclinical animal cancer models and in a phase 1/2 clinical trial in patients with advanced cancers. mda-7/IL-24 targets specific miRNAs, including miR-221 and miR-320, for down-regulation in a cancer-selective manner. We demonstrate that mda-7/IL-24, administered through a replication incompetent type 5 adenovirus (Ad.mda-7) or with His-MDA-7/IL-24 protein, down-regulates DICER, a critical regulator in miRNA processing. This effect is specific for mature miR-221, as it does not affect Pri-miR-221 expression, and the DICER protein, as no changes occur in other miRNA processing cofactors, including DROSHA, PASHA, or Argonaute. DICER is unchanged by Ad.mda-7/IL-24 in normal immortal prostate cells, whereas Ad.mda-7 down-regulates DICER in multiple cancer cells including glioblastoma multiforme and prostate, breast, lung, and liver carcinoma cells. MDA-7/IL-24 protein down-regulates DICER expression through canonical IL-20/IL-22 receptors. Gain- and loss-of-function studies confirm that overexpression of DICER rescues deregulation of miRNAs by mda-7/IL-24, partially rescuing cancer cells from mda-7/IL-24-mediated cell death. Stable overexpression of DICER in cancer cells impedes Ad.mda-7 or His-MDA-7/IL-24 inhibition of cell growth, colony formation, PARP cleavage, and apoptosis. In addition, stable overexpression of DICER renders cancer cells more resistant to Ad.mda-7 inhibition of primary and secondary tumor growth. MDA-7/IL-24-mediated regulation of DICER is reactive oxygen species-dependent and mediated by melanogenesis-associated transcription factor. Our research uncovers a distinct role of mda-7/IL-24 in the regulation of miRNA biogenesis through alteration of the MITF-DICER pathway.

CYTL1 inhibits tumor metastasis with decreasing STAT3 phosphorylation

CYTL1 is a novel cytokine that was first identified in CD34⁺ hematopoietic cells. We previously prepared recombinant CYTL1 and verified that it chemoattracted human monocytes via the CCR2/ERK pathway. It has been reported that CYTL1 plays contradictory roles in neuroblastoma and lung cancer. We found that the expression level of CYTL1 was notably decreased and it was hypermethylated in various tumors, including breast and lung cancer, by bioinformatics analyses. After validating the expression of CYTL1 in lung cancer, we identified that CYTL1 exerted no obvious effect on tumor cell proliferation but inhibited their migration and invasion, and these effects were accompanied by decreasing STAT3 phosphorylation, using recombinant CYTL1 and CYTL1-overexpressing tumor cell lines. Furthermore, we constructed experimental and spontaneous metastasis models of breast cancer in BALB/c mice and found that CYTL1 significantly inhibited tumor metastasis in vivo. In summary, CYTL1 is a cytokine with tumor-suppressing characteristics that inhibits tumor metastasis and STAT3 phosphorylation in multiple types of tumors.

Eukaryotic Translation Initiation Factor 4A Down-Regulation Mediates Interleukin-24-Induced Apoptosis through Inhibition of Translation

Dysregulated activity of helicase eIF4A drives transformation to and maintenance of cancer cell phenotype by reprogramming cellular translation. Interleukin 24 (IL-24) is a tumor-suppressing protein, which has the ability to inhibit angiogenesis, sensitize cancer cells to chemotherapy, and induce cancer cell-specific apoptosis. In this study, we found that eIF4A is inhibited by IL-24. Consequently, selective reduction of translation was observed for mRNAs harboring strong secondary structures in their 5′-untranslated regions (5′UTRs). These mRNAs encode proteins, which function in cell survival and proliferation. Consistently, overexpression of eIF4A conferred cancer cells with resistance to IL-24-induced cell death. It has been established that inhibition of eIF4A triggers mitochondrial-mediated apoptosis. We showed that IL-24 induces eIF4A-dependent mitochondrial depolarization. We also showed that IL-24 induces Sigma 1 Receptor-dependent eIF4A down-regulation and mitochondrial depolarization. Thus, the progress of apoptosis triggered by IL-24 is characterized by a complex program of changes in regulation of several initiation factors, including the eIF4A.