Recombinant Human IFN-βAffects Androgen Receptor Level, Neuroendocrine Differentiation, Cell Adhesion, and Motility in Prostate Cancer Cells

MiR-139 Induces an Interferon-β Response in Prostate Cancer Cells by Binding to RIG-1

BACKGROUND

We previously identified a panel of five miRNAs associated with prostate cancer recurrence and metastasis. Expression of one of the down-regulated miRNAs, miR-139-5p, was significantly associated with a lower incidence of biochemical recurrence and metastasis. Transcriptome profiling of miR-139-expressing prostate cancer cells revealed up-regulation of genes involved in interferon (IFN) stimulation. The association between miR-139 and IFN-β was further explored in this study.

MATERIALS AND METHODS

We examined miR-139 transfected PC3, Du145 and LNCaP cells and the associated IFN response by transcriptome sequencing, immunoblotting and pulldown assays.

RESULTS

Treatment of prostate cancer cells by miR-139 resulted in the up-regulation of IFN-related genes. Specifically, miR-139 induced expression of the IFN-β protein. The ability of miR-139 to induce IFN-β was due to its binding to RIG-1 and the induction of IFN-related genes was found to be dependent on RIG-1 expression.

CONCLUSION

miR-139 acts as an immune agonist of RIG-1 to enhance IFN-β response in prostate cancer cells.

Acetylation of interferon regulatory factor-5 suppresses androgen receptor and downregulates expression of Sox2

Interferon regulatory factor-5 (IRF5) is a transcription factor and has essential cellular mechanisms as a tumour suppressor gene. IRF5 protein function is irregular in various human cancers, and its role in prostate cancer is also unknown. This study presents the first evidence that IRF5 expression is controlled with androgen receptor (AR) signalling interaction and stem cell factors (Nanog, Oct4, Sox2) in prostate cancer. Human prostate cancer cell lines (PC3, DU145 and LNCaP) were transfected plasmids and assessed for cellular localization of IRF5 and AR interaction with IF-staining. Co-immunoprecipitation and ChIP assay were used to detect the IRF5 and AR protein-protein interaction and IRF5 stem cell factors protein-gene interaction. The target relation between IRF5, AR, CREB, p300, ISRE, ARE and NF-кB was tested by luciferase assay. IRF5 was low expressed in androgen-dependent prostate cancer cells and tissues. The analysis of human prostate cancer clinical samples supports the interaction of IRF5 and AR in a pathological role, as IRF5 expression is down-regulated in the tumours' advanced stages. Tumour suppression mechanism of IRF5 and SOX2 levels in cells reduces and causes AR acetylation. Those affect the prostate cancer mechanism by modifying the cellular response in the signal pathway. IRF5 can be promising for treating androgen-dependent prostate cancers and is a therapeutic protein for new drug studies.

Antitumor activity of interferon-β1a in hormone refractory prostate cancer with neuroendocrine differentiation

PURPOSE

Type I interferons (IFN-α and IFN-β) are a class of cytokines that exert several biological activities, such as modulation of cell proliferation and differentiation and of the immune system. Although these cytokines interact with a common receptor complex, IFN-β showed a more potent antitumor activity than IFN-α in several tumor models. New recombinant human IFN-β products, such as IFN-β1a and IFN-β1b, have been produced in order to improve the stability and bioavailability of natural IFN-β. In this report, we analyzed the effects of recombinant IFN-β1a on the cell proliferation of two human androgen-resistant prostate cancer cell lines with neuroendocrine differentiation (DU-145, PC-3) and related mechanisms of action.

METHODS

The effects of IFN-β1a on the cell growth proliferation, cell cycle, and apoptosis have been evaluated in DU-145 and PC-3 cells through MTT assay, DNA flow cytometry with propidium iodide, and Annexin V-FITC/propidium iodide staining, respectively. Moreover, the expression of neuron-specific enolase (NSE), cleaved caspase-3, caspase-8, and PARP was evaluated through Western blotting.

RESULTS

IFN-β1a showed a significant anti-proliferative activity in both androgen-resistant cell lines. This effect was related to cell cycle perturbation and induction in apoptosis, as shown by flow cytometric analysis, the activation of caspase-3 and caspase-8 and PARP cleavage during incubation with IFN-β1a. Moreover, this cytokine reduced the expression of NSE in both cell lines.

CONCLUSIONS

Recombinant IFN-β1a (Rebif) showed a potent in vitro anti-proliferative activity in androgen-resistant prostate cancer cells, and it could represent a promising tool for the treatment of this tumor.

Effects of interferons and double-stranded RNA on human prostate cancer cell apoptosis

Prostate cancer is the second most commonly diagnosed cancer among men in the United States. Prostate cancer therapy is severely hampered by lack of response and development of resistance to conventional chemotherapeutic drugs in patients. Therefore, the development and discovery of new drugs have become an urgent clinical need. Interferons (IFNs), a family of pleiotropic cytokines, exert antitumor activities due to their anti-proliferative, immunomodulatory and proapoptotic functions. Here, we report that pretreatment of prostate cancer PC-3 cells with IFNs sensitized these cells to double-stranded RNAs (dsRNAs)-induced apoptosis. The enhancement effect of IFN treatment was dependent on IFN subtypes, in particular, IFN γ. In comparison with IFN α or β, IFN γ treatment remarkably augmented apoptosis in PC-3 cells induced with polyinosinic:polycytidylic acid (poly I:C), a synthesized form of dsRNA. We demonstrated that IFN-signaling was necessary for these effects by using mutant cell lines. Transfection of 2-5A, the activator of RNase L, or silencing of dsRNA-dependent protein kinase R (PKR) by siRNA did not have any significant impact on this event, suggesting that neither RNase L nor PKR was involved in poly I:C/IFN γ-induced apoptosis in the cells. Further investigation of the apoptotic pathway revealed that Bak, a pro-apoptotic member of the Bcl-2family, was synergistically up-regulated by IFN γ and poly I:C, whereas other members of the family were not affected. Knocking down of Bak demonstrated its contribution to poly I:C/IFN γ-induced apoptosis in the cells. We believeour findings will precipitate the design of novel therapeutic strategies for prostate cancer.

Interferon-β gene transfer inhibits melanoma cells adhesion and migration

We evaluated the effects of expression of interferon-β (IFNβ) after lipofection on melanoma cells adhesion and migration. Three canine mucosal (Ak, Br and Ol) and one human dermal (SB2) melanomas were assayed. By means of the wound healing assay, we found a significant inhibitory effect of canine IFNβ gene expression on cells migration in Br and Ol monolayers. This effect could be reproduced on unlipofected Ol cells with conditioned culture media obtained from canine IFNβ gene-lipofected Ol cells, and with recombinant human IFNβ on unlipofected SB2 cells. Furthermore, IFNβ gene expression of the four tested tumor cells significantly inhibited their adhesion to extracellular matrix (ECM) proteins and their spreading from multicellular spheroids onto gelatin coating. The addition of catalase reverted the increase of reactive oxygen species (ROS) in Ol cells and the inhibition of cell migration in monolayers (Ol) and spheroids (Ol an SB2) produced by canine and human IFNβ expression, suggesting the involvement of ROS as mediators of IFNβ action on the cells interactions with ECM. Together with its known immune, antiangiogenic and cytotoxic effects, the present data strongly support more studies exploring the clinical potential of IFNβ for cancer therapy.

Interferon-β gene-modified human bone marrow mesenchymal stem cells attenuate hepatocellular carcinoma through inhibiting AKT/FOXO3a pathway

OBJECTIVE

This study aims to investigate the using of bone marrow mesenchymal stem cells (BMSCs) genetically engineered to produce interferon-β (IFN-β) as a gene delivery system to treat hepatocellular carcinoma (HCC) in vitro and in vivo.

METHODS

To measure the effects on tumour cell growth in vitro, IFN-β-producing BMSCs (BMSC/IFN-β) were co-cultured with the HCC cell line HepG2 and Huh7. Enzyme-linked immunosorbent assay (ELISA) was used to detect the IFN-β secretion in the BMSC culture condition medium (CM). The effect of BMSC/IFN-β on HCC cells proliferation was examined both in vitro and in vivo by using MTT, colony formation assay, BrdU staining, cell cycle analysis, and xenografted NOD/SCID mouse tumour model. To examine the impact of BMSC/IFN-β on the AKT/FOXO3a signalling, RT-PCR and western blotting were performed.

RESULTS

The BMSC/IFN-β cells can stably secrete high levels of IFN-β. Both MTT and colony forming assay showed that HCC cells had a lower growth rate when cultured in BMSC/IFN-β-CM as compared with that in BMSC/vector-CM or DMEM culture group. Co-culture with BMSC/IFN-β-CM dramatically decreased the percentages of cells with incorporated BrdUrd. In BMSC/IFN-β-CM-treated HCC cells, the proportion of G1-phase cells increased but it decreased in the S phase of the cell. The BMSC/IFN-β inhibited HCC growth in NOD/SCID mice and proved the survival period of these mice. Compared with the control group, p21 and p27 expression of hepatoma cells increased, whereas cyclin D1 and phosphorylation of Rb expression decreased when co-cultured with BMSC/IFN-β-CM. It was associated with suppression of Akt activity and enhanced transcriptional activity of FOXO3a.

CONCLUSION

The IFN-β gene-modified BMSCs can effectively inhibit the proliferation of HCC cells in vitro and in vivo through inhibiting AKT/FOXO3a pathway. These results indicate that BMSC/IFN-β are a powerful anticancer cytotherapeutic tool for HCC.

Mesenchymal stem cells modified to express interferon-β inhibit the growth of prostate cancer in a mouse model

OBJECTIVE

This study investigated use of mesenchymal stem cells (MSCs) genetically engineered to produce interferon-β (IFN-β) as a gene delivery system to treat prostate cancer in an animal model.

METHODS

To measure the effects on tumour cell growth in vitro, IFN-β-producing MSCs (IFN-β-MSCs) were co-cultured with the prostate cancer cell line PC-3. The in vivo migration of intravenously injected fluorescently-labelled MSCs to healthy tissues and PC-3 xenograft tumours grown in immuno-deficient mice was determined by fluorescence microscopy. The antitumour effects of intravenously injected IFN-β-MSCs on PC-3 xenograft growth and animal survival were also investigated.

RESULTS

IFN-β-MSCs inhibited the growth of PC-3 cells in vitro. Fluorescently-labelled MSCs migrated to the margins and centre of tumour masses but not into healthy tissues. Intravenously injected IFN-β-MSCs significantly reduced PC-3 xenograft tumour weight and increased animal survival compared with controls.

CONCLUSIONS

Intravenously injected IFN-β-MSCs inhibited PC-3 xenograft growth. This could be an effective gene delivery system for treatment of solid human tumours.