MDA-7/IL-24 functions as a tumor suppressor gene in vivo in transgenic mouse models of breast cancer

Independent organelle and organelle-organelle interactions: essential mechanisms for malignant gynecological cancer cell survival

Different eukaryotic cell organelles (e.g., mitochondria, endoplasmic reticulum, lysosome) are involved in various cancer processes, by dominating specific cellular activities. Organelles cooperate, such as through contact points, in complex biological activities that help the cell regulate energy metabolism, signal transduction, and membrane dynamics, which influence survival process. Herein, we review the current studies of mechanisms by which mitochondria, endoplasmic reticulum, and lysosome are related to the three major malignant gynecological cancers, and their possible therapeutic interventions and drug targets. We also discuss the similarities and differences of independent organelle and organelle-organelle interactions, and their applications to the respective gynecological cancers; mitochondrial dynamics and energy metabolism, endoplasmic reticulum dysfunction, lysosomal regulation and autophagy, organelle interactions, and organelle regulatory mechanisms of cell death play crucial roles in cancer tumorigenesis, progression, and response to therapy. Finally, we discuss the value of organelle research, its current problems, and its future directions.

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.

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.

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.

Reduced infiltration of regulatory T cells in tumours from mice fed daily with gamma-tocotrienol supplementation

Gamma-tocotrienol (γT3) is an analogue of vitamin E with beneficial effects on the immune system, including immune-modulatory properties. This study reports the immune-modulatory effects of daily supplementation of γT3 on host T helper (Th) and T regulatory cell (Treg ) populations in a syngeneic mouse model of breast cancer. Female BALB/c mice were fed with either γT3 or vehicle (soy oil) for 2 weeks via oral gavage before they were inoculated with syngeneic 4T1 mouse mammary cancer cells (4T1 cells). Supplementation continued until the mice were euthanized. Mice (n = 6) were euthanized at specified time-points for various analysis (blood leucocyte, cytokine production and immunohistochemistry). Tumour volume was measured once every 7 days. Gene expression studies were carried out on tumour-specific T lymphocytes isolated from splenic cultures. Supplementation with γT3 increased CD4+ (p < 0.05), CD8+ (p < 0.05) T-cells and natural killer cells (p < 0.05) but suppressed Treg cells (p < 0.05) in peripheral blood when compared to animals fed with the vehicle. Higher interferon (IFN)-γ and lower transforming growth factor (TGF)-ꞵ levels were noted in the γT3 fed mice. Immunohistochemistry findings revealed higher infiltration of CD4+ cells, increased expression of interleukin-12 receptor-beta-2 (IL-12ꞵ2R), interleukin (IL)-24 and reduced expression of cells that express the forkhead box P3 (FoxP3) in tumours from the γT3-fed animals. Gene expression studies showed the down-regulation of seven prominent genes in splenic CD4+ T cells isolated from γT3-fed mice. Supplementation with γT3 from palm oil-induced T cell-dependent cell-mediated immune responses and suppressed T cells in the tumour microenvironment in a syngeneic mouse model of breast cancer.

IL-24 inhibits the malignancy of human glioblastoma cells via destabilization of Zeb1

Glioblastoma (GBM) is the most common and fatal type of primary malignant tumours in the central nervous system. Cytokines such as interleukins (ILs) play an important role in GBM progression. Our present study found that IL-24 is down-regulated in GBM cells. Recombinant IL-24 (rIL-24) can suppress the in vitro migration and invasion of GBM cells while increase its chemo-sensitivity to temozolomide (TMZ) treatment. rIL-24 negatively regulates the expression of Zeb1, one well known transcription factors of epithelial to mesenchymal transition (EMT) of cancer cells. Over expression of Zeb1 can attenuate IL-24-suppressed malignancy of GBM cells. Mechanistically, IL-24 decreases the protein stability of Zeb1 while has no effect on its mRNA stability. It is due to that IL-24 can increase the expression of FBXO45, which can destabilize Zeb1 in cancer cells. Collectively, we reveal that IL-24 can suppress the malignancy of GBM cells via decreasing the expression of Zeb1. It suggests that targeted activation of IL-24 signals might be a potential therapy approach for GBM treatment.

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.

Theranostic Tripartite Cancer Terminator Virus for Cancer Therapy and Imaging

Simple Summary

An optimum cancer therapeutic virus should embody unique properties, including an ability to: Selectively procreate and kill tumor but not normal cells; produce a secreted therapeutic molecule (with broad-acting anti-cancer effects on primary and distant metastatic cells because of potent “bystander” activity); and monitor therapy non-invasively by imaging primary and distant metastatic cancers. We previously created a broad-spectrum, cancer-selective and replication competent therapeutic adenovirus that embodies two of these properties, i.e., specifically reproduces in cancer cells and produces a therapeutic cytokine, MDA-7/IL-24, a “cancer terminator virus” (CTV). We now expand on this concept and demonstrate the feasibility of producing a tripartite CTV (TCTV) selectively expressing three genes from three distinct promoters that replicate in the cancer cells while producing MDA-7/IL-24 and an imaging gene (i.e., luciferase). This novel first-in-class tripartite “theranostic” TCTV expands the utility of therapeutic viruses to non-invasively image and selectively destroy primary tumors and metastases.

Abstract

Combining cancer-selective viral replication and simultaneous production of a therapeutic cytokine, with potent “bystander” anti-tumor activity, are hallmarks of the cancer terminator virus (CTV). To expand on these attributes, we designed a next generation CTV that additionally enables simultaneous non-invasive imaging of tumors targeted for eradication. A unique tripartite CTV “theranostic” adenovirus (TCTV) has now been created that employs three distinct promoters to target virus replication, cytokine production and imaging capabilities uniquely in cancer cells. Conditional replication of the TCTV is regulated by a cancer-selective (truncated PEG-3) promoter, the therapeutic component, MDA-7/IL-24, is under a ubiquitous (CMV) promoter, and finally the imaging capabilities are synchronized through another cancer selective (truncated tCCN1) promoter. Using in vitro studies and clinically relevant in vivo models of breast and prostate cancer, we demonstrate that incorporating a reporter gene for imaging does not compromise the exceptional therapeutic efficacy of our previously reported bipartite CTV. This TCTV permits targeted treatment of tumors while monitoring tumor regression, with potential to simultaneously detect metastasis due to the cancer-selective activity of reporter gene expression. This “theranostic” virus provides a new genetic tool for distinguishing and treating localized and metastatic cancers.

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.

IL-24 inhibits endometrial cancer cell proliferation by promoting apoptosis through the mitochondrial intrinsic signaling pathway

BACKGROUND

Endometrial cancer is a type of malignant tumor of the female reproductive system. Preserving fertility in endometrial cancer patients is currently a formidable challenge. Interleukin-24 (IL-24) is a unique cytokine tumor suppressor gene belonging to the IL-10 cytokine family. IL-24 has broad-spectrum antitumor activity through different signaling pathways but does not affect normal cells. IL-24 gene therapy may provide a new method for the treatment of endometrial cancer.

METHODS

Transfection was used for gene transfer. The expression of IL-24 and related pathway proteins in endometrial cancer tissue and the Ishikawa cell line was detected by immunohistochemistry and Western blotting, respectively. The antitumor function of IL-24 was examined in vitro and in vivo. Cell proliferation was determined by CCK-8 assay, cell migration was shown by wound-healing assay, and cell invasion was detected by Transwell assay. Apoptosis was analyzed by TUNEL assay, and HE staining was performed to observe the morphology of the samples.

RESULTS

Immunohistochemical analysis showed different expression levels of IL-24 in human endometrial cancer tissues and normal endometrial tissues. IL-24 increased protein expression of BAX and Cytochrome C, while BCL-2, MMP-3, VEGF, Caspase-9 and Caspase-3 expression was decreased. Overexpression of IL-24 inhibited cell proliferation, migration and invasion, but increased cell apoptosis in endometrial cancer. Mechanistically, we demonstrated that IL-24 inhibited endometrial cancer cell growth by inducing cell apoptosis through the mitochondrial intrinsic signaling pathway. In addition, IL-24 inhibited tumor development by inducing cell apoptosis and inhibiting angiogenesis, as shown in xenograft tumor experiments.

CONCLUSIONS

Our study demonstrates the antitumor effect of IL-24 on endometrial cancer and shows that IL-24 may be a promising therapeutic gene for endometrial cancer gene therapy.

Prospects of Gene Therapy to Treat Melanoma

The incidence of melanoma has continued to increase over the past 30 years. Hence, developing effective therapies to treat both primary and metastatic melanoma are essential. While advances in targeted therapy and immunotherapy have provided novel therapeutic options to treat melanoma, gene therapy may provide additional strategies for the treatment of metastatic melanoma clinically. This review focuses upon the challenges and opportunities that gene therapy provides for targeting melanoma. We begin with a discussion of the various gene therapy targets which are relevant to melanoma. Next, we explore the gene therapy clinical trials that have been conducted for treating melanoma. Finally, challenges faced in gene therapy as well as combination therapies for targeting melanoma, which may circumvent these obstacles, will be discussed. Targeted combination gene therapy strategies hold significant promise for developing the most effective therapeutic outcomes, while reducing the toxicity to noncancerous cells, and would integrate the patient's immune system to diminish melanoma progression. Next-generation vectors designed to embody required safety profiles and "theranostic" attributes, combined with immunotherapeutic strategies would be critical in achieving beneficial management and therapeutic outcomes in melanoma patients.

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.

Immunogenicity moderation effect of interleukin-24 on myelogenous leukemia cells

Previous studies have shown that interleukin-24 (IL-24) has tumor-suppressing activity by multiple pathways. However, the immunogenicity moderation effect of IL-24 on malignant cells has not been explored extensively. In this study, we investigated the role of IL-24 in immunogenicity modulation of the myelogenous leukemia cells. Data show that myelogenous leukemia cells express low levels of immunogenicity molecules. Treatment with IL-24 could enhance leukemia cell immunogenicity, predominantly regulate leukemia cells to produce immune-associated cytokines, and improve the cytotoxic sensitivity of these cells to immune effector cells. IL-24 expression could retard transplanted leukemia cell tumor growth in vivo in athymic nude mice. Moreover, IL-24 had marked effects on downregulating the expression of angiogenesis-related proteins vascular endothelial growth factor, cluster of differentiation (CD) 31, CD34, collagen IV and metastasis-related factors CD147, membrane type-1 matrix metalloproteinase (MMP), and MMP-2 and MMP-9 in transplanted tumors. These findings indicated novel functions of this antitumor gene and characterized IL-24 as a promising agent for further clinical trial for hematologic malignancy immunotherapy.

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.

MDA-7/interleukin 24 (IL-24) in tumor gene therapy: application of tumor penetrating/homing peptides for improvement of the effects

INTRODUCTION

MDA-7/Interleukin-24 (IL-24), as a pleiotropic cytokine, exhibits a specific tumor suppression property that has attracted a great deal of attention. While its anti-tumor induction is mostly attributed to endogenous gene expression, attachment of secreted MDA-7/IL-24 to cognate receptors also triggers the death of cancerous cell via different pathways. Therefore, precise targeting of secreted MDA-7/IL-24 to tumor cells would render it more efficacy and specificity.

AREAS COVERED

In order to target soluble cytokines, particularly MDA-7/IL-24 to the neighbor tumor sites and enhance their therapeutic efficiency, fusing with cell penetrating peptides (CPPs) or Tumor homing peptides (THPs) seems logical due to the improvement of their bystander effects. Although the detailed anti-tumor mechanisms of endogenous mda-7/IL-24 have been largely investigated, the significance of the secreted form in these activities and methods of its improving by CPPs or THPs need more discussion.

EXPERT OPINION

While the employment of CPPs/THPs for the improvement of cytokine gene therapy is desirable, to create fusions of CPPs/THPs with MDA-7/IL-24, some hurdles are not avoidable. Regarding our expertise, herein, the importance of CPPs/THPs, needs for their elegant designing in a fusion structure, and their applications in cytokine gene therapy are discussed with a special focus on mda-7/IL-24.

In Vivo Pharmacology Models for Cancer Target Research

Experimental animal tumor models have been broadly used to evaluate anticancer drugs in the preclinical setting. They have also been widely applied for drug target discovery and validation, which usually follows four experimental strategies: first, assess the roles of putative drug targets using in vivo tumorigenicity and tumor growth kinetics assays of transplanted tumors, engineered through gain-of-function (GOF) by overexpressing transgene or knock-in (KI) or loss-of-function by gene silencing using knockdown (KD) or knockout (KO) or mutation via mutagenesis procedures; second, similarly genetically engineered mouse models (GEMM), through either germline or somatic cell procedures, are used to test the roles of potential targets in spontaneous tumorigenicity assays; third, patient-derived xenografts (PDXs), which most closely resemble patient genetics and histopathology, are used in tumor inhibition assays for evaluating target-/pathway-specific inhibitors, including large and small molecules, thus assessing the drug target; and fourth, the targets can be assessed in population-based trials, mouse clinical trials (MCT), so that the validation can be generally meaningful as performed in human clinical trials. This chapter outlines the commonly used protocols in cancer drug target research: the first four sections describe four sets of different, specific pharmacology protocols used in the respective cancer modeling stages, with the last section summarizing the common protocols applicable to all four pharmacology modeling steps.

Expression, purification, and cytotoxic evaluation of IL24-BR2 fusion protein

Interleukin (IL) 24 is a pro-inflammatory and tumor suppressor cytokine capable of inducing selective apoptosis in various cancer cells. BR2, on the other hand, is an anti-microbial peptide with selective penetrability to the cancer cells. In this study, we aimed to produce and purify a fusion protein containing IL24 as the toxic moiety fused to BR2, as targeting moiety, and then to evaluate its cytotoxic activities. For this purpose, the coding sequence of IL24-BR2 fusion protein and IL24 were cloned into the pET28a vector and used to transform E. coli BL21 (DE3) cells. Following induction of expression, protein purification performed using Ni-NTA chromatography. SDS-PAGE and western blotting were performed to confirm the expression and purification. Finally, cytotoxic effects of the purified proteins were evaluated on MCF-7 and HUVEC cell lines. Analysis of crude lysate of induced recombinant E. coli BL21 (DE3) bacteria and also purified proteins showed a band of approximately 22 and 18 KDa on SDS-PAGE and western blotting for IL24-BR2 and IL24, respectively. Finally, statistical analysis showed significant cytotoxic effects of IL24-BR2 on MCF-7 cells at 10, 20, and 40 µg/mL concentrations compared to IL24 alone, which showed no significant cytotoxic effects on cancer cells except in the highest concentration. In conclusion, production and purification of IL24-BR2 fusion protein with potential specific toxicity toward cancer cells was successfully achieved. However, further investigation of the cytotoxic effects of this fusion protein on other cell lines and in vivo cancer models must be performed.

Macrophages are exploited from an innate wound healing response to facilitate cancer metastasis

Tumour-associated macrophages (TAMs) play an important role in tumour progression, which is facilitated by their ability to respond to environmental cues. Here we report, using murine models of breast cancer, that TAMs expressing fibroblast activation protein alpha (FAP) and haem oxygenase-1 (HO-1), which are also found in human breast cancer, represent a macrophage phenotype similar to that observed during the wound healing response. Importantly, the expression of a wound-like cytokine response within the tumour is clinically associated with poor prognosis in a variety of cancers. We show that co-expression of FAP and HO-1 in macrophages results from an innate early regenerative response driven by IL-6, which both directly regulates HO-1 expression and licenses FAP expression in a skin-like collagen-rich environment. We show that tumours can exploit this response to facilitate transendothelial migration and metastatic spread of the disease, which can be pharmacologically targeted using a clinically relevant HO-1 inhibitor.

Tumor angiogenesis and anti-angiogenic gene therapy for cancer

When Folkman first suggested a theory about the association between angiogenesis and tumor growth in 1971, the hypothesis of targeting angiogenesis to treat cancer was formed. Since then, various studies conducted across the world have additionally confirmed the theory of Folkman, and numerous efforts have been made to explore the possibilities of curing cancer by targeting angiogenesis. Among them, anti-angiogenic gene therapy has received attention due to its apparent advantages. Although specific problems remain prior to cancer being fully curable using anti-angiogenic gene therapy, several methods have been explored, and progress has been made in pre-clinical and clinical settings over previous decades. The present review aimed to provide up-to-date information concerning tumor angiogenesis and gene delivery systems in anti-angiogenic gene therapy, with a focus on recent developments in the study and application of the most commonly studied and newly identified anti-angiogenic candidates for anti-angiogenesis gene therapy, including interleukin-12, angiostatin, endostatin, tumstatin, anti-angiogenic metargidin peptide and endoglin silencing.

Enhanced tumor growth inhibition by mesenchymal stem cells derived from iPSCs with targeted integration of interleukin24 into rDNA loci

Induced pluripotent stem cells (iPSCs) are a promising source of mesenchymal stem cells (MSCs) for clinical applications. In this study, we transformed human iPSCs using a non-viral vector carrying the IL24 transgene pHrn-IL24. PCR and southern blotting confirmed IL24 integration into the rDNA loci in four of 68 iPSC clones. We then differentiated a high expressing IL24-iPSC clone into MSCs (IL24-iMSCs) that showed higher expression of IL24 in culture supernatants and in cell lysates than control iMSCs. IL24-iMSCs efficiently differentiated into osteoblasts, chondrocytes and adipocytes. Functionally, IL24-iMSCs induced in vitro apoptosis in B16-F10 melanoma cells more efficiently than control iMSCs when co-cultured in Transwell assays. In vivo tumor xenograft studies in mice demonstrated that IL24-iMSCs inhibited melanoma growth more than control iMSCs did. Immunofluorescence and histochemical analysis showed larger necrotic areas and cell nuclear aggregation in tumors with IL24-iMSCs than control iMSCs, indicating that IL24-iMSCs inhibited tumor growth by inducing apoptosis. These findings demonstrate efficient transformation of iPSCs through gene targeting with non-viral vectors into a rDNA locus. The ability of these genetically modified MSCs to inhibit in vivo melanoma growth is suggestive of the clinical potential of autologous cell therapy in cancer.

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

Subtraction hybridization identified genes displaying differential expression as metastatic human melanoma cells terminally differentiated and lost tumorigenic properties by treatment with recombinant fibroblast interferon and mezerein. This approach permitted cloning of multiple genes displaying enhanced expression when melanoma cells terminally differentiated, called melanoma differentiation associated (mda) genes. One mda gene, mda-7, has risen to the top of the list based on its relevance to cancer and now inflammation and other pathological states, which based on presence of a secretory sequence, chromosomal location, and an IL-10 signature motif has been named interleukin-24 (MDA-7/IL-24). Discovered in the early 1990s, MDA-7/IL-24 has proven to be a potent, near ubiquitous cancer suppressor gene capable of inducing cancer cell death through apoptosis and toxic autophagy in cancer cells in vitro and in preclinical animal models in vivo. In addition, MDA-7/IL-24 embodied profound anticancer activity in a Phase I/II clinical trial following direct injection with an adenovirus (Ad.mda-7; INGN-241) in tumors in patients with advanced cancers. In multiple independent studies, MDA-7/IL-24 has been implicated in many pathological states involving inflammation and may play a role in inflammatory bowel disease, psoriasis, cardiovascular disease, rheumatoid arthritis, tuberculosis, and viral infection. This review provides an up-to-date review on the multifunctional gene mda-7/IL-24, which may hold potential for the therapy of not only cancer, but also other pathological states.

Lentivirus‑mediated MDA7/IL24 expression inhibits the proliferation of hepatocellular carcinoma cells

MDA7/IL24 is a member of the IL-10 gene family that functions as a cytokine. Notably, supra-physiological endogenous MDA7 levels have been indicated to suppress tumor growth and induce apoptosis in different cancer types. In the present study, MDA7 roles were investigated during the proliferation of hepatocellular carcinoma (HCC) cells and the molecular mechanisms underlying this process. A lentiviral vector expressing MDA7/IL24 (LV-MDA7/IL24) was constructed and used to infect HCC SMMC-7721 cells. The expression levels of MDA7/IL24 in these cells were determined using RT-qPCR and western blot analysis. The effects of LV-MDA7/IL24 on cell proliferation were analyzed using MTT and colony formation assays. Furthermore, the influence of LV-MDA7/IL24 on cell apoptosis and cell cycle distribution were detected using flow cytometry. The underlying molecular mechanisms were investigated using microarray and western blot analysis. The expression of MDA7/IL24 was confirmed to be significantly increased in the cells infected with LV-MDA7/IL24 compared with that the negative-control infected group. Lentivirus-mediated MDA7/IL24 expression was found to inhibit HCC cell proliferation and colony formation, and it also induced cell arrest and apoptosis. Microarray analysis and western blotting results indicated that multiple cancer-associated pathways and oncogenes are regulated by MDA7/IL24, including cell cycle regulatory and apoptosis activation pathway. In conclusion, it was determined that MDA7/IL24 inhibits the proliferation and reduces the tumorigenicity of HCC cells by regulating cell cycle progression and inducing apoptosis, indicating that it may be used as a potential prognostic and therapeutic target in HCC.

Low expression of Mda-7/IL-24 and high expression of C-myb in tumour tissues are predictors of poor prognosis for Burkitt lymphoma patients

Objectives Burkitt lymphoma is one of the most common types of haematopoietic malignancy in children and adolescents. Mda-7/IL-24 had been identified as a differentiation inducer of Burkitt lymphoma cells. Previous studies have revealed that knockdown of C-myb can also lead to the terminal differentiation of Burkitt lymphoma cells. The aim of the present study was to investigate the correlation between the expression of Mda-7/IL-24 and C-myb, as well as their prognostic significance, for Burkitt lymphoma patients. Methods The tumour tissues were collected from 59 cases of Burkitt lymphoma patients and detected with Western blotting and immunohistochemistry. Results The results showed that the expression of Mda-7/IL-24 was lower, whereas the expression of C-myb was higher in Burkitt lymphoma tissues compared to specimens of normal lymph node tissues. Furthermore, C-myb expression was negatively correlated with Mda-7/IL-24 expression at the protein level in Burkitt lymphoma tissues and cell lines. Both the expression of Mda-7/IL-24 and C-myb in Burkitt lymphoma tissues was associated with some clinicopathological parameters, such as clinical stage, infiltration in the bone marrow, Ki67 and overall survival rates. Conclusion These results indicated that low expression of Mda-7/IL-24 along with high expression of C-myb are predictors for poor prognosis of Burkitt lymphoma patients; this outcome suggests that Mda-7/IL-24 and C-myb might be potential targets for clinical treatment of Burkitt lymphoma.

ABBREVIATIONS

Mda-7/IL-24: melanoma differentiation associated gene7/interleukin 24; FCM: flow cytometry; Ecog: Eastern Cooperative Oncology Group; IPI: International lymphoma prognosis index.

Melanoma differentiation-associated gene-7 suppresses human gastric cancer cell invasion and migration

Gastric cancer is one of the most common types of cancer in the world. Patients with gastric cancer often respond poorly to conventional chemotherapies, therefore more comprehensive therapy is required. Melanoma differentiation-associated gene-7 (MDA-7), also termed interleukin-24, is a potent tumor suppressor gene. Numerous studies have demonstrated that MDA-7 suppresses the growth and induces the apoptosis of cancer cells. In the present study, the MDA-7 gene was transfected into human gastric cancer AGS cells using adenovirus. Transwell and wound healing assays were performed to evaluate AGS cell invasion and migration, respectively. Western blotting was used to detect the expression of epithelial (E)-cadherin, cluster of differentiation (CD)44 and matrix metalloproteinase (MMP)-2 and MMP-9 proteins. A recombinant virus package was successfully constructed, and it was verified using western blotting that exogenous MDA-7 was highly expressed in the AGS cells. MDA-7 overexpression inhibited invasion and migration, decreased CD44, MMP-2 and MMP-9 expression, and increased epithelial (E-)cadherin expression in the AGS cells. Results of the present study revealed that MDA-7 inhibits gastric cancer invasion and metastasis by inhibiting CD44, MMP-2 and MMP-9 expression and by promoting E-cadherin expression.

The Enigma of miRNA Regulation in Cancer

MicroRNAs (miRNAs or miRs) are small 19-22 nucleotide long, noncoding, single-stranded, and multifunctional RNAs that regulate a diverse assortment of gene and protein functions that impact on a vast network of pathways. Lin-4, a noncoding transcript discovered in 1993 and named miRNA, initiated the exploration of research into these intriguing molecules identified in almost all organisms. miRNAs interfere with translation or posttranscriptional regulation of their target gene and regulate multiple biological actions exerted by these target genes. In cancer, they function as both oncogenes and tumor suppressor genes displaying differential activity in various cellular contexts. Although the role of miRNAs on target gene functions has been extensively investigated, less is currently known about the upstream regulatory molecules that regulate miRNAs. This chapter focuses on the factors and processes involved in miRNA regulation.

miR-203a-3p.1 targets IL-24 to modulate hepatocellular carcinoma cell growth and metastasis

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer‐related death. Cytokines, including interleukin 24 (IL‐24), play an important role in HCC. IL‐24 inhibits HCC metastasis but the molecular mechanism by which this occurs is still unknown. MicroRNAs (miRNAs) are regulators of cancers including hepatocellular carcinoma (HCC). However, the role that miRNAs play in the regulation of IL‐24 in HCC is unclear. The aim of this study was to investigate the effects of regulation of IL‐24 by miR‐203a‐3p.1 on liver cancer cell proliferation and metastasis. IL‐24 mRNA and miR‐203a‐3p.1 were detected by real‐time RT‐PCR, and IL‐24 protein in the cell growth medium was measured by ELISA. A luciferase assay was used to verify that the IL‐24 gene was the target of miR‐203a‐3p.1. Cell survival ability was detected by the MTT assay and colony formation. Cell metastasis was assayed by the Transwell system. The results showed that IL‐24 could be down‐regulated by miR‐203a‐3p.1 in HCC cells and that miR‐203a‐3p.1 acted as an onco‐miRNA by targeting IL‐24. Inhibition of miR‐203a‐3p.1 in cells could lead to the reversal of HCC cell proliferation and metastasis. The study highlights a novel molecular interaction between miR‐203a‐3p.1 and IL‐24, which indicates that IL‐24 and miR‐203a‐3p.1 may constitute potential therapeutic targets for HCC.

Suppression of Her2/Neu mammary tumor development in mda-7/IL-24 transgenic mice

Melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24) encodes a tumor suppressor gene implicated in the growth of various tumor types including breast cancer. We previously demonstrated that recombinant adenovirus-mediated mda-7/IL-24 expression in the mammary glands of carcinogen-treated (methylnitrosourea, MNU) rats suppressed mammary tumor development. Since most MNU-induced tumors in rats contain activating mutations in Ha-ras, which arenot frequently detected in humans, we presently examined the effect of MDA-7/IL-24 on Her2/Neu-induced mammary tumors, in which the RAS pathway is induced. We generated tet-inducible MDA-7/IL-24 transgenic mice and crossed them with Her2/Neu transgenic mice. Triple compound transgenic mice treated with doxycycline exhibited a strong inhibition of tumor development, demonstrating tumor suppressor activity by MDA-7/IL-24 in immune-competent mice. MDA-7/IL-24 induction also inhibited growth of tumors generated following injection of Her2/Neu tumor cells isolated from triple compound transgenic mice that had not been treated with doxycycline, into the mammary fat pads of isogenic FVB mice. Despite initial growth suppression, tumors in triple compound transgenic mice lost mda-7/IL-24 expression and grew, albeit after longer latency, indicating that continuous presence of this cytokine within tumor microenvironment is crucial to sustain tumor inhibitory activity. Mechanistically, MDA-7/IL-24 exerted its tumor suppression effect on HER2⁺ breast cancer cells, at least in part, through PERP, a member of PMP-22 family with growth arrest and apoptosis-inducing capacity. Overall, our results establish mda-7/IL-24 as a suppressor of mammary tumor development and provide a rationale for using this cytokine in the prevention/treatment of human breast cancer.

The IL-24 gene protects human umbilical vein endothelial cells against H₂O₂-induced injury and may be useful as a treatment for cardiovascular disease

The aim of the present study was to investigate the protective effects of interleukin-24 (IL-24) on hydrogen peroxide (H₂O₂)-induced vascular endothelial injury and to examine the association between IL-24 and cardiovascular disease. Human umbilical vein endothelial cells (HUVECs) were exposed to increasing concentrations of H₂O₂ in the presence or absence of IL-24, which was introduced via Lipofectamine^® 2000-mediated transfection. The successful uptake of the IL-24 plasmid was confirmed by RT-PCR at 24 h post-transfection. The effects of H₂O₂ and IL-24 on the proliferation and migration of the HUVECs was determined using cell migration assays. Cell viability was determined using a Cell Counting Kit-8 (CCK-8). Apoptosis and the measurement of the intracellular reactive oxygen species (ROS) levels were determined by flow cytometry, and the levels of caspase-3, which is associated with apoptosis, were determined by western blot analysis. Real-time PCR and western blot analysis were also used to measure the levels of multiple cardiovascular disease-associated factors. In vivo experiments were also performed using a rat model of hypertension which was constructed by angiotensin II infusion using an osmotic pump. The mRNA and protein levels of IL-24 were measured in both the control and hypertensive rats; the effects of treatment with enalapril and nifedipine on the IL-24 levels were also examined. Our results revealed that IL-24 protected against the H₂O₂-mediated abnormal increase in HUVEC proliferation. IL-24 also antagonized H₂O₂ by reducing the content of ROS in the cells, thus decreasing cellular oxidative damage, improving the cellular survival rate, reducing apoptosis and decreasing the expression of cardiovascular disease-related factors. The results from our in vivo animal experiments revealed that IL-24 expression was lower in the hypertensive rats compared to the healthy controls. Additionally, the IL-24 levels increased following anti-hypertensive therapy. The findings of our study indicate that IL-24 protects against H₂O₂-mediated endothelial cell damage and may thus provide a novel therapeutic strategy for treatment of cardiovascular disease.