Interferon receptor expression regulates the antiproliferative effects of interferons on cancer cells and solid tumors

Nanoparticles Targeting Lymph Nodes for Cancer Immunotherapy: Strategies and Influencing Factors

Immunotherapy has emerged as a potent strategy in cancer treatment, with many approved drugs and modalities in the development stages. Despite its promise, immunotherapy is not without its limitations, including side effects and suboptimal efficacy. Using nanoparticles (NPs) as delivery vehicles to target immunotherapy to lymph nodes (LNs) can improve the efficacy of immunotherapy drugs and reduce side effects in patients. In this context, this paper reviews the development of LN-targeted immunotherapeutic NP strategies, the mechanisms of NP transport during LN targeting, and their related biosafety risks. NP targeting of LNs involves either passive targeting, influenced by NP physical properties, or active targeting, facilitated by affinity ligands on NP surfaces, while alternative methods, such as intranodal injection and high endothelial venule (HEV) targeting, have uncertain clinical applicability and require further research and validation. LN targeting of NPs for immunotherapy can reduce side effects and increase biocompatibility, but risks such as toxicity, organ accumulation, and oxidative stress remain, although strategies such as biodegradable biomacromolecules, polyethylene glycol (PEG) coating, and impurity addition can mitigate these risks. Additionally, this work concludes with a future-oriented discussion, offering critical insights into the field.

Estrogen receptor α-mediated signaling inhibits type I interferon response to promote breast carcinogenesis

Estrogen receptor α (ERα) is an important driver and therapeutic target in ∼70% of breast cancers. How ERα drives breast carcinogenesis is not fully understood. In this study, we show that ERα is a negative regulator of type I interferon (IFN) response. Activation of ERα by its natural ligand estradiol inhibits IFN-β-induced transcription of downstream IFN-stimulated genes (ISGs), whereas ERα deficiency or the stimulation with its antagonist fulvestrant has opposite effects. Mechanistically, ERα induces the expression of the histone 2A variant H2A.Z to restrict the engagement of the IFN-stimulated gene factor 3 (ISGF3) complex to the promoters of ISGs and also interacts with STAT2 to disrupt the assembly of the ISGF3 complex. These two events mutually lead to the inhibition of ISG transcription induced by type I IFNs. In a xenograft mouse model, fulvestrant enhances the ability of IFN-β to suppress ERα+ breast tumor growth. Consistently, clinical data analysis reveals that ERα+ breast cancer patients with higher levels of ISGs exhibit higher long-term survival rates. Taken together, our findings suggest that ERα inhibits type I IFN response via two distinct mechanisms to promote breast carcinogenesis.

Novel immunotherapeutic options for BCG-unresponsive high-risk non-muscle-invasive bladder cancer

BACKGROUND

High-risk non-muscle-invasive bladder cancer (HR-NMIBC) presents a challenge to many physicians due to its ability to resist Bacillus Calmette-Guérin (BCG) intravesical therapy and the substantial rate of progression into muscle-invasive bladder cancer (MIBC). Patients who are BCG-unresponsive have worse prognosis and thus require further management including radical cystectomy (RC), which significantly impacts quality of life. Moreover, the ongoing worldwide shortage of BCG warrants the need for policies that prioritize drug use and utilize alternative treatment strategies. Hence, there is a significant unmet need for bladder preserving therapy in this subset of patients.

METHODS

To address this issue, we searched the relevant literature in PUBMED for articles published from 2019 through May of 2023 using appropriate keywords. All clinical trials of patients with HR-NMIBC treated with immune-related agents were retrieved from clinicaltrials.gov.

FINDINGS AND FUTURE PERSPECTIVES

Exploratory treatments for BCG-Unresponsive HR-NMIBC included immune checkpoint inhibitors (ICI), oncolytic viral therapy, cytokine agonists, and other immunomodulators targeting TLR, EpCaM, FGFR, MetAP2, and IDO1. Some combination therapies have been found to work synergistically and are preferred therapeutically over monotherapy. Three drugs-pembrolizumab, valrubicin, and most recently, nadofaragene firadenovec-vncg-have been FDA approved for the treatment of BCG-unresponsive NMIBC in patients who are ineligible for or decline RC. However, all explored treatment options tend to postpone RC rather than provide long-term disease control. Additional combination strategies need to be studied to enhance the effects of immunotherapy. Despite the challenges faced in finding effective therapies, many potential treatments are currently under investigation. Addressing the landscape of biomarkers, mechanisms of progression, BCG resistance, and trial design challenges in HR-NMIBC is essential for the discovery of new targets and the development of effective treatments.

Modelling the spatial dynamics of oncolytic virotherapy in the presence of virus-resistant tumour cells

Oncolytic virotherapy is a promising form of cancer treatment that uses native or genetically engineered viruses to target, infect and kill cancer cells. Unfortunately, this form of therapy is not effective in a substantial proportion of cancer patients, partly due to the occurrence of infection-resistant tumour cells. To shed new light on the mechanisms underlying therapeutic failure and to discover strategies that improve therapeutic efficacy we designed a cell-based model of viral infection. The model allows us to investigate the dynamics of infection-sensitive and infection-resistant cells in tumour tissue in presence of the virus. To reflect the importance of the spatial configuration of the tumour on the efficacy of virotherapy, we compare three variants of the model: two 2D models of a monolayer of tumour cells and a 3D model. In all model variants, we systematically investigate how the therapeutic outcome is affected by the properties of the virus (e.g. the rate of viral spread), the tumour (e.g. production rate of resistant cells, cost of resistance), the healthy stromal cells (e.g. degree of resistance to the virus) and the timing of treatment. We find that various therapeutic outcomes are possible when resistant cancer cells arise at low frequency in the tumour. These outcomes depend in an intricate but predictable way on the death rate of infected cells, where faster death leads to rapid virus clearance and cancer persistence. Our simulations reveal three different causes of therapy failure: rapid clearance of the virus, rapid selection of resistant cancer cells, and a low rate of viral spread due to the presence of infection-resistant healthy cells. Our models suggest that improved therapeutic efficacy can be achieved by sensitizing healthy stromal cells to infection, although this remedy has to be weighed against the toxicity induced in the healthy tissue.

Immunomodulatory antitumor effect of interferon‑beta combined with gemcitabine in pancreatic cancer

Resistance to gemcitabine is common and critically limits its therapeutic efficacy in patients with pancreatic cancer. Interferon‑beta (IFN‑β) induces numerous antitumor effects and synergizes with gemcitabine treatment. The immunomodulatory effects of this treatment regimen have not yet been described. In the present study, the antitumor effect of IFN‑β combined with gemcitabine was investigated in immune competent mice. Mouse KPC3 cells were used in all experiments. Treatment effects were determined with cell proliferation assay. Reverse transcription‑quantitative PCR was used to measure gene expression. For in vivo experiments, cells were subcutaneously injected in immune competent mice. For immune profiling, NanoString analysis was performed on tumor samples of treated and untreated mice. Baseline expression of Ifnar‑1 and Ifnar‑2c in KPC3 cells was 1.42±0.16 and 1.50±0.17, respectively. IC50 value of IFN‑β on cell growth was high (>1,000 IU/ml). IFN‑β pre‑treatment increased the in vitro response to gemcitabine (1.3‑fold decrease in EC50; P<0.001). In vivo, tumor size was not statistically significant smaller in mice treated with IFN‑β plus gemcitabine (707±92 mm3 vs. 1,239±338 mm3 in vehicle‑treated mice; P=0.16). IFN‑β alone upregulated expression of numerous immune‑related genes. This effect was less pronounced when combined with gemcitabine. For the first time, to the best of our knowledge, the immunomodulatory effects of IFN‑β, alone and combined with gemcitabine, in pancreatic cancer were reported. Prognostic markers for predicting effective responses to IFN‑β therapy are urgently needed.

Determinants of Ligand Specificity and Functional Plasticity in Type I Interferon Signaling

The Type I Interferon family of cytokines all act through the same cell surface receptor and induce phosphorylation of the same subset of response regulators of the STAT family. Despite their shared receptor, different Type I Interferons have different functions during immune response to infection. In particular, they differ in the potency of their induced anti-viral and anti-proliferative responses in target cells. It remains not fully understood how these functional differences can arise in a ligand-specific manner both at the level of STAT phosphorylation and the downstream function. We use a minimal computational model of Type I Interferon signaling, focusing on Interferon-α and Interferon-β. We validate the model with quantitative experimental data to identify the key determinants of specificity and functional plasticity in Type I Interferon signaling. We investigate different mechanisms of signal discrimination, and how multiple system components such as binding affinity, receptor expression levels and their variability, receptor internalization, short-term negative feedback by SOCS1 protein, and differential receptor expression play together to ensure ligand specificity on the level of STAT phosphorylation. Based on these results, we propose phenomenological functional mappings from STAT activation to downstream anti-viral and anti-proliferative activity to investigate differential signal processing steps downstream of STAT phosphorylation. We find that the negative feedback by the protein USP18, which enhances differences in signaling between Interferons via ligand-dependent refractoriness, can give rise to functional plasticity in Interferon-α and Interferon-β signaling, and explore other factors that control functional plasticity. Beyond Type I Interferon signaling, our results have a broad applicability to questions of signaling specificity and functional plasticity in signaling systems with multiple ligands acting through a bottleneck of a small number of shared receptors.

Actin Cytoskeleton Dynamics and Type I IFN-Mediated Immune Response: A Dangerous Liaison in Cancer?

Simple Summary

Actin cytoskeleton is a dynamic subcellular component critical for maintaining cell shape and for elaborating response to any stimulus converging on the cell. Cytoskeleton constantly interfaces with diverse cellular components and affects a wide range of processes important in homeostasis and disease. What has been clearly demonstrated to date is that pathogens modify and use host cytoskeleton to their advantage. What is now emerging is that in sterile conditions, when a chronic inflammation occurs as in cancer, the subversion of tissue homeostasis induces an alarm status which mimics infection. This activates cellular players similar to those that solve an infection, but their persistence may pave the way for tumor progression. Understanding molecular mechanisms engaged by cytoskeleton to induce this viral mimicry could improve our knowledge of processes governing tumor progression and resistance to therapy.

Abstract

Chronic viral infection and cancer are closely inter-related and are both characterized by profound alteration of tissue homeostasis. The actin cytoskeleton dynamics highly participate in tissue homeostasis and act as a sensor leading to an immune-mediated anti-cancer and anti-viral response. Herein we highlight the crucial role of actin cytoskeleton dynamics in participating in a viral mimicry activation with profound effect in anti-tumor immune response. This still poorly explored field understands the cytoskeleton dynamics as a platform of complex signaling pathways which may regulate Type I IFN response in cancer. This emerging network needs to be elucidated to identify more effective anti-cancer strategies and to further advance the immuno-oncology field which has revolutionized the cancer treatment. For a progress to occur in this exciting arena we have to shed light on actin cytoskeleton related pathways and immune response. Herein we summarize the major findings, considering the double sword of the immune response and in particular the role of Type I IFN pathways in resistance to anti-cancer treatment.

Cancer immunotherapy from biology to nanomedicine

With the significant drawbacks of conventional cancer chemotherapeutics, cancer immunotherapy has demonstrated the ability to eradicate cancer cells and circumvent multidrug resistance (MDR) with fewer side effects than traditional cytotoxic therapies. Various immunotherapeutic agents have been investigated for that purpose including checkpoint inhibitors, cytokines, monoclonal antibodies and cancer vaccines. All these agents aid immune cells to recognize and engage tumor cells by acting on tumor-specific pathways, antigens or cellular targets. However, immunotherapeutics are still associated with some concerns such as off-target side effects and poor pharmacokinetics. Nanomedicine may resolve some limitations of current immunotherapeutics such as localizing delivery, controlling release and enhancing the pharmacokinetic profile. Herein, we discuss recent advances of immunotherapeutic agents with respect to their development and biological mechanisms of action, along with the advantages that nanomedicine strategies lend to immunotherapeutics by possibly improving therapeutic outcomes and minimizing side effects.

Genetically engineered mesenchymal stem cells: targeted delivery of immunomodulatory agents for tumor eradication

Cancer immunotherapy emerged as a novel therapeutic option that employs enhanced or amended native immune system to create a robust response against malignant cells. The systemic therapies with immune-stimulating cytokines have resulted in substantial dose-limiting toxicities. Targeted cytokine immunotherapy is being explored to overcome the heterogeneity of malignant cells and tumor cell defense with a remarkable reduction of systemic side effects. Cell-based strategies, such as dendritic cells (DCs), fibroblasts or mesenchymal stem cells (MSCs) seek to minimize the numerous toxic side effects of systemic administration of cytokines for extended periods of time. The usual toxicities comprised of a vascular leak, hypotension, and respiratory insufficiency. Natural and strong tropism of MSCs toward malignant cells made them an ideal systemic delivery vehicle to direct the proposed therapeutic genes to the vicinity of a tumor where their expression could evoke an immune reaction against the tumor. Compared with other methods, the delivery of cytokines via engineered MSCs is safer and renders a more practical, and promising strategy. Large numbers of genes code for cytokines have been utilized to reengineer MSCs as therapeutic cells. This review highlights the recent findings on the cytokine gene therapy for human malignancies by focusing on MSCs application in cancer immunotherapy.

In vitro antiproliferation activity of Typhonium flagelliforme leaves ethanol extract and its combination with canine interferons on several tumor-derived cell lines

BACKGROUND AND AIM

Tumor disorder is one of the degenerative diseases that affected human and animals and recently is tend to increase significantly. The treatment of tumor diseases can be performed through surgical, chemotherapy, radiotherapy, biological substances, and herbs medicine. Typhonium flagelliforme leaves extract known to have an antiproliferation activity, while interferons (IFNs) one of the cytokines that first used as an antiviral agent was also known to have antitumor activity. Nowadays, the treatment of tumors using a traditional way, including the use of herbal substances, becomes popular. Some limitations of the antitumor activity due to resistant development of the cell to some substances were one of the problems on why the treatment of cancer was unsuccessful. This study aimed to elaborate the synergistic effect on the antiproliferation and anti-angiogenesis activities of the combinations between T. flagelliforme leaves ethanol extract and canine natural (natural canine IFN [nCaIFN]) and recombinant (recombinant canine IFN [rCaIFN]) IFNs on tumor-derived cell lines to find the new potential antitumor substances.

MATERIALS AND METHODS

The extraction of T. flagelliforme leaves was performed using the maceration method and followed by phytochemical screening assays. According to the result of LC50 by the brine shrimp lethality test, the dose used for T. flagelliforme extract was 120 ppm while the dose of IFNs was 102 U/ml. The tumor-derived cell lines (canine squamous cell carcinoma [CSCC], canine mammary gland benign mixed tumor/MCM-IPB-B3, and feline squamous cell carcinoma [FSCC]) and normal rabbit endothelial cells were cultured and maintained on Dulbecco's Modified Eagle's Medium DMEM/Ham-F12 medium supplemented with 10% fetal calf serum, antibiotic, and antifungal. The antiproliferation activity was assayed by calculated the total cell number after treated with the tested substances. The antiangiogenesis assay was performed using in vitro method on rabbit normal endothelial cells and in ovo using chicken chorioallantoic membrane (CAM).

RESULTS

The phytochemical screening test of the T. flagelliforme leaves ethanol extract indicated that the compound consisted of flavonoid, steroid, and tannin. The antiproliferation activity was increased in the combination of substances compared to the single exposure of each substance on all tested tumor-derived cell lines. There was no significantly different on the antiproliferation activity between a combination of T. flagelliforme with nCaIFN or rCaIFN in every single tested cell lines, but the comparison of this activity among the three tumor-derived cell lines seem that the antiproliferation activity is more effective on CSCC cell lines compared to the canine mammary gland benign mixed tumor and FSCC cell lines. A similar pattern of synergistic effect was also detected on the anti-angiogenesis activity in vitro using rabbit endothelial cells as well as in ovo assays. The most effective of the in vitro and in ovo anti-angiogenesis activity was observed on the combination substances between T. flagelliforme extract and rCaIFN compared to other treatments.

CONCLUSION

There was a synergistic effect on the antiproliferation and antiangiogenesis activities of the combination between T. flagelliforme and canine IFNs (natural and recombinant) and this result could be developed as another alternative on the cancer treatments.

Antiviral interferons induced by Newcastle disease virus (NDV) drive a tumor-selective apoptosis

Newcastle disease virus (NDV) strongly induces both type I and III antiviral interferons (IFNs-α/-β and IFN-λ, respectively) in tumor cells while it induces mainly type III IFN in normal cells. Impairment of antiviral type I IFN signaling in tumor cells is thought to be the reason for effective oncolysis. However, there is lack of clarity why lentogenic strain NDV can also induce oncolysis. NDV infection caused apoptosis in normal and tumor cells as demonstrated with the caspase-3 enzyme activation and annexin-V detection. The apoptosis response was inhibited by B18R protein (a type I IFN inhibitor) in tumor cells i.e. A549 and U87MG, and not in normal cells i.e. NB1RGB and HEK293. Similarly, UV-inactivated medium from NDV infection was shown to induce apoptosis in corresponding cells and the response was inhibited in A549 and U87MG cells with the addition of B18R protein. Treatment with combination of IFNs-α/-β/-λ or IFNs-α/-β or IFN-λ in NB1RGB, HEK293, A549 and U87MG showed that caspase activity in IFNs-α/-β/-λ group was the highest, followed with IFN-α/-β group and IFN-λ group. This suggests that tumor-selectivity of NDV is mainly because of the cumulative effect of type I and III in tumor cells that lead to higher apoptotic effect.

The lytic activity of VSV-GP treatment dominates the therapeutic effects in a syngeneic model of lung cancer

Background

Oncolytic virotherapy is thought to result in direct virus-induced lytic tumour killing and simultaneous activation of innate and tumour-specific adaptive immune responses. Using a chimeric vesicular stomatitis virus variant VSV-GP, we addressed the direct oncolytic effects and the role of anti-tumour immune induction in the syngeneic mouse lung cancer model LLC1.

Methods

To study a tumour system with limited antiviral effects, we generated interferon receptor-deficient cells (LLC1-IFNAR1^−/−). Therapeutic efficacy of VSV-GP was assessed in vivo in syngeneic C57BL/6 and athymic nude mice bearing subcutaneous tumours. VSV-GP treatment effects were analysed using bioluminescent imaging (BLI), immunohistochemistry, ELISpot, flow cytometry, multiplex ELISA and Nanostring® assays.

Results

Interferon insensitivity correlated with VSV-GP replication and therapeutic outcome. BLI revealed tumour-to-tumour spread of viral progeny in bilateral tumours. Histological and gene expression analysis confirmed widespread and rapid infection and cell killing within the tumour with activation of innate and adaptive immune-response markers. However, treatment outcome was increased in the absence of CD8⁺ T cells and surviving mice showed little protection from tumour re-challenge, indicating limited therapeutic contribution by the activated immune system.

Conclusion

These studies present a case for a predominantly lytic treatment effect of VSV-GP in a syngeneic mouse lung cancer model.

Potent antileukemic activity of curaxin CBL0137 against MLL-rearranged leukemia

Around 10% of acute leukemias harbor a rearrangement of the MLL/KMT2A gene, and the presence of this translocation results in a highly aggressive, therapy-resistant leukemia subtype with survival rates below 50%. There is a high unmet need to identify safer and more potent therapies for MLL-rearranged (MLL-r) leukemia that can be combined with established chemotherapeutics to decrease treatment-related toxicities. The curaxin, CBL0137, has demonstrated nongenotoxic anticancer and chemopotentiating effects in a number of preclinical cancer models and is currently in adult Phase I clinical trials for solid tumors and hematological malignancies. The aim of our study was to investigate whether CBL0137 has potential as a therapeutic and chemopotentiating compound in MLL-r leukemia through a comprehensive analysis of its efficacy in preclinical models of the disease. CBL0137 decreased the viability of a panel of MLL-r leukemia cell lines (n = 12) and xenograft cells derived from patients with MLL-r acute lymphoblastic leukemia (ALL, n = 3) in vitro with submicromolar IC50s. The small molecule drug was well-tolerated in vivo and significantly reduced leukemia burden in a subcutaneous MV4;11 MLL-r acute myeloid leukemia model and in patient-derived xenograft models of MLL-r ALL (n = 5). The in vivo efficacy of standard of care drugs used in remission induction for pediatric ALL was also potentiated by CBL0137. CBL0137 exerted its anticancer effect by trapping Facilitator of Chromatin Transcription (FACT) into chromatin, activating the p53 pathway and inducing an Interferon response. Our findings support further preclinical evaluation of CBL0137 as a new approach for the treatment of MLL-r leukemia.

Type I interferons and dendritic cells in cancer immunotherapy

Type I interferons (IFNs) facilitate cancer immunosurveillance, antitumor immunity and antitumor efficacy of conventional cell death-inducing therapies (chemotherapy/radiotherapy) as well as immunotherapy. Moreover, it is clear that dendritic cells (DCs) play a significant role in aiding type I IFN-driven immunity. Owing to these antitumor properties several immunotherapies involving, or inducing, type I IFNs have received considerable clinical attention, e.g., recombinant IFNα2 or agonists targeting pattern recognition receptor (PRR) pathways like Toll-like receptors (TLRs), cGAS-STING or RIG-I/MDA5/MAVS. A series of preclinical and clinical evidence concurs that the success of anticancer therapy hinges on responsiveness of both cancer cells and DCs to type I IFNs. In this article, we discuss this link between type I IFNs and DCs in the context of cancer biology, with particular attention to mechanisms behind type I IFN production, their impact on DC driven anticancer immunity, and the implications of this for cancer immunotherapy, including DC-based vaccines.

MicroRNA hsa-miR-324-5p Suppresses H5N1 Virus Replication by Targeting the Viral PB1 and Host CUEDC2

MicroRNAs (miRNAs) are small noncoding RNAs that are crucial posttranscriptional regulators for host mRNAs. Recent studies indicate that miRNAs may modulate host response during RNA virus infection. However, the role of miRNAs in immune response against H5N1 infection is not clearly understood. In this study, we showed that expression of cellular miRNA miR-324-5p was downregulated in A549 cells in response to infection with RNA viruses H5N1, A/PR8/H1N1, and Newcastle disease virus (NDV) and transfection with poly(I·C). We found that miR-324-5p inhibited H5N1 replication by targeting the PB1 viral RNA of H5N1 in host cells. In addition, transcriptome analysis revealed that miR-324-5p enhanced the expression of type I interferon, type III interferon, and interferon-inducible genes (ISGs) by targeting CUEDC2, the negative regulator of the JAK1-STAT3 pathway. Together, these findings highlight that the miR-324-5p plays a crucial role in host defense against H5N1 by targeting viral PB1 and host CUEDC2 to inhibit H5N1 replication.IMPORTANCE Highly pathogenic influenza A virus (HPAIV) continues to pose a pandemic threat globally. From 2003 to 2017, H5N1 HPAIV caused 453 human deaths, giving it a high mortality rate (52.74%). This work shows that miR-324-5p suppresses H5N1 HPAIV replication by directly targeting the viral genome (thereby inhibiting viral gene expression) and cellular CUEDC2 gene, the negative regulator of the interferon pathway (thereby enhancing antiviral genes). Our study enhances the knowledge of the role of microRNAs in the cellular response to viral infection. Also, the study provides help in understanding how the host cells utilize small RNAs in controlling the viral burden.

Plasticity of Type I Interferon-Mediated Responses in Cancer Therapy: From Anti-tumor Immunity to Resistance

The efficacy of several therapeutic strategies against cancer, including cytotoxic drugs, radiotherapy, targeted immunotherapies and oncolytic viruses, depend on intact type I interferon (IFN) signaling for the promotion of both direct (tumor cell inhibition) and indirect (anti-tumor immune responses) effects. Malfunctions of this pathway in tumor cells or in immune cells may be responsible for the lack of response or resistance. Although type I IFN signaling is required to trigger anti-tumor immunity, emerging evidence indicates that chronic activation of type I IFN pathway may be involved in mediating resistance to different cancer treatments. The plastic and dynamic features of type I IFN responses should be carefully considered to fully exploit the therapeutic potential of strategies targeting IFN signaling. Here, we review available evidence supporting the involvement of type I IFN signaling in mediating resistance to various cancer therapies and highlight the most promising modalities that are being tested to overcome resistance.

Identification of differentially expressed genes in human breast cancer cells induced by 4-hydroxyltamoxifen and elucidation of their pathophysiological relevance and mechanisms

While tamoxifen (TAM) is used for treating estrogen receptor (ER)a-positive breast cancer patients, its anti-breast cancer mechanisms are not completely elucidated. This study aimed to examine effects of 4-hydroxyltamoxifen (4-OH-TAM) on ER-positive (ER⁺) breast cancer MCF-7 cell growth and gene expression profiles. MCF-7 cell growth was inhibited by 4-OH-TAM dose-dependently with IC₅₀ of 29 μM. 332 genes were up-regulated while 320 genes were down-regulated. The mRNA levels of up-regulated genes including STAT1, STAT2, EIF2AK2, TGM2, DDX58, PARP9, SASH1, RBL2 and USP18 as well as down-regulated genes including CCDN1, S100A9, S100A8, ANXA1 and PGR were confirmed by quantitative real-time PCR (qRT-PCR). In human breast tumor tissues, mRNA levels of EIF2Ak2, USP18, DDX58, RBL2, STAT2, PGR, S1000A9, and CCND1 were significantly higher in ER⁺- than in ER^--breast cancer tissues. The mRNA levels of EIF2AK2, TGM2, USP18, DDX58, PARP9, STAT2, STAT1, PGR and CCND1 were all significantly higher in ER⁺-tumor tissues than in their corresponding tumor-adjacent tissues. These genes, except PGR and CCND1 which were down-regulated, were also up-regulated in ER⁺ MCF-7 cells by 4-OH-TAM. Total 14 genes mentioned above are involved in regulation of cell proliferation, apoptosis, cell cycles, and estrogen and interferon signal pathways. Bioinformatics analysis also revealed other novel and important regulatory factors that are associated with these genes and involved in the mentioned functional processes. This study has paved a foundation for elucidating TAM anti-breast cancer mechanisms in E2/ER-dependent and independent pathways.

Immunomodulatory and antitumor effects of type I interferons and their application in cancer therapy

During the last decades, the pleiotropic antitumor functions exerted by type I interferons (IFNs) have become universally acknowledged, especially their role in mediating interactions between the tumor and the immune system. Indeed, type I IFNs are now appreciated as a critical component of dendritic cell (DC) driven T cell responses to cancer. Here we focus on IFN-α and IFN-β, and their antitumor effects, impact on immune responses and their use as therapeutic agents. IFN-α/β share many properties, including activation of the JAK-STAT signaling pathway and induction of a variety of cellular phenotypes. For example, type I IFNs drive not only the high maturation status of DCs, but also have a direct impact in cytotoxic T lymphocytes, NK cell activation, induction of tumor cell death and inhibition of angiogenesis. A variety of stimuli, including some standard cancer treatments, promote the expression of endogenous IFN-α/β, which then participates as a fundamental component of immunogenic cell death. Systemic treatment with recombinant protein has been used for the treatment of melanoma. The induction of endogenous IFN-α/β has been tested, including stimulation through pattern recognition receptors. Gene therapies involving IFN-α/β have also been described. Thus, harnessing type I IFNs as an effective tool for cancer therapy continues to be studied.

Optimizing tumor immune response through combination of radiation and immunotherapy

Radiation therapy and immunotherapy are two highly evolving modalities for the treatment of solid tumors. Immunotherapeutic drugs can either stimulate the immune system via immunogenic pathways or target co-inhibitory checkpoints. An augmented tumor cell recognition by host immune cells can be achieved post-irradiation, as irradiated tissues can release chemical signals which are sensed by the immune system resulting in its activation. Different strategies combining both treatment modalities were tested in order to achieve a better therapeutic response and longer tumor control. Both regimens act synergistically to one another with complimentary mechanisms. In this review, we explore the scientific basis behind such a combination, starting initially with a brief historical overview behind utilizing radiation and immunotherapies for solid tumors, followed by the different types of these two modalities, and the biological concept behind their synergistic effect. We also shed light on the common side effects and toxicities associated with radiation and immunotherapy. Finally, we discuss previous clinical trials tackling this multimodality combination and highlight future ongoing research.

Role of Type I and II Interferons in Colorectal Cancer and Melanoma

Cancer can be considered an aberrant organ with a hierarchical composition of different cell populations. The tumor microenvironment, including the immune cells and related cytokines, is crucial during all the steps of tumor development. In particular, type I and II interferons (IFNs) are involved in a plethora of mechanisms that regulate immune responses in cancer, thus balancing immune escape versus immune surveillance. IFNs are involved in both the direct and indirect regulation of cancer cell proliferation and metastatic potential. The mutational background of genes involved in IFNs signaling could serve as a prognostic biomarker and a powerful tool to screen cancer patients eligible for checkpoint blocking therapies. We herewith describe the latest findings regarding the contribution of IFNs in colorectal cancer and melanoma by researching their dual role as either tumor promoter or suppressor, in diverse tumor types, and microenvironmental context. We are reporting the most innovative and promising approaches of IFN-based therapies that have achieved considerable outcomes in clinical oncology practice and explain the possible mechanisms responsible for their failure.

Brief Report: Increased Expression of the Type I Interferon Receptor on CD4+ T Lymphocytes in HIV-1-Infected Individuals

BACKGROUND

Type I interferons (IFN1s; eg, interferon-alpha and interferon-beta) are potent cytokines that inhibit the replication of human immunodeficiency virus-1 (HIV-1) and other viruses. The antiviral and immunoregulatory activities of IFN1 are mediated through ligand-receptor interactions with the IFN1 receptor complex (IFNAR). Variation in the cell-surface density of IFNAR could play a role in HIV-1 pathogenesis.

METHODS

In this cross-sectional study of fresh whole blood, we used flow cytometry to evaluate the expression of IFNAR2 on lymphocyte subsets from HIV-1-infected (n = 33) and HIV-1-uninfected (n = 22) individuals.

RESULTS

In comparison with healthy blood bank donors, we observed that the HIV-1-infected individuals, particularly those having advanced to disease, exhibited the increased expression of IFNAR2 on CD4 T cells (relative fluorescence intensity 6.9 vs. 9.0; P = 0.027). The CD4:CD4 T-cell IFNAR2 expression-level ratio provides an internally standardized measure of this alteration. The observed increased expression of IFNAR2 was largely restricted to CD4 T cells that expressed the chemokine receptor CXCR4 and lacked the expression of CCR5.

CONCLUSIONS

HIV-1-infected individuals exhibit an increased expression of the IFN1 receptor on CD4 T cells. The level of IFNAR2 expression seems to increase with disease progression. These findings provide insight for the immunologic alterations associated with HIV-1 infection and possibly new therapeutic approaches.

The molecular basis for differential type I interferon signaling

Type I interferons (IFN-1) are cytokines that affect the expression of thousands of genes, resulting in profound cellular changes. IFN-1 activates the cell by dimerizing its two-receptor chains, IFNAR1 and IFNAR2, which are expressed on all nucleated cells. Despite a similar mode of binding, the different IFN-1s activate a spectrum of activities. The causes for differential activation may stem from differences in IFN-1-binding affinity, duration of binding, number of surface receptors, induction of feedbacks, and cell type-specific variations. All together these will alter the signal that is transmitted from the extracellular domain inward. The intracellular domain binds, directly or indirectly, different effector proteins that transmit signals. The composition of effector molecules deviates between different cell types and tissues, inserting an additional level of complexity to the system. Moreover, IFN-1s do not act on their own, and clearly there is much cross-talk between the activated effector molecules by IFN-1 and other cytokines. The outcome generated by all of these factors (processing step) is an observed phenotype, which can be the transformation of the cell to an antiviral state, differentiation of the cell to a specific immune cell, senescence, apoptosis, and many more. IFN-1 activities can be divided into robust and tunable. Antiviral activity, which is stimulated by minute amounts of IFN-1 and is common to all cells, is termed robust. The other activities, which we term tunable, are cell type-specific and often require more stringent modes of activation. In this review, I summarize the current knowledge on the mode of activation and processing that is initiated by IFN-1, in perspective of the resulting phenotypes.

Antitumour actions of interferons: implications for cancer therapy

The interferons (IFNs) are a family of cytokines that protect against disease by direct effects on target cells and by activating immune responses. The production and actions of IFNs are finely tuned to achieve maximal protection and avoid the potential toxicity associated with excessive responses. IFNs are back in the spotlight owing to mounting evidence that is reshaping how we can exploit this pathway therapeutically. As IFNs can be produced by, and act on, both tumour cells and immune cells, understanding this reciprocal interaction will enable the development of improved single-agent or combination therapies that exploit IFN pathways and new 'omics'-based biomarkers to indicate responsive patients.

Basic Overview of Current Immunotherapy Approaches in Cancer

Recent success of immunotherapy strategies such as immune checkpoint blockade in several malignancies has established the role of immunotherapy in the treatment of cancer. Cancers use multiple mechanisms to co-opt the host-tumor immune interactions, leading to immune evasion. Our understanding of the host-tumor interactions has evolved over the past few years and led to various promising new therapeutic strategies. This article will focus on the basic principles of immunotherapy, novel pathways/agents, and combinatorial immunotherapies.

Interferon Beta and Interferon Alpha 2a Differentially Protect Head and Neck Cancer Cells from Vesicular Stomatitis Virus-Induced Oncolysis

Oncolytic viruses (OV) preferentially kill cancer cells due in part to defects in their antiviral responses upon exposure to type I interferons (IFNs). However, IFN responsiveness of some tumor cells confers resistance to OV treatment. The human type I IFNs include one IFN-β and multiple IFN-α subtypes that share the same receptor but are capable of differentially inducing biological responses. The role of individual IFN subtypes in promoting tumor cell resistance to OV is addressed here. Two human IFNs which have been produced for clinical use, IFN-α2a and IFN-β, were compared for activity in protecting human head and neck squamous cell carcinoma (HNSCC) lines from oncolysis by vesicular stomatitis virus (VSV). Susceptibility of HNSCC lines to killing by VSV varied. VSV infection induced increased production of IFN-β in resistant HNSCC cells. When added exogenously, IFN-β was significantly more effective at protecting HNSCC cells from VSV oncolysis than was IFN-α2a. In contrast, normal keratinocytes and endothelial cells were protected equivalently by both IFN subtypes. Differential responsiveness of tumor cells to IFN-α and -β was further supported by the finding that autocrine IFN-β but not IFN-α promoted survival of HNSCC cells during persistent VSV infection. Therefore, IFN-α and -β differentially affect VSV oncolysis, justifying the evaluation and comparison of IFN subtypes for use in combination with VSV therapy. Pairing VSV with IFN-α2a may enhance selectivity of oncolytic VSV therapy for HNSCC by inhibiting VSV replication in normal cells without a corresponding inhibition in cancer cells.

IMPORTANCE

There has been a great deal of progress in the development of oncolytic viruses. However, a major problem is that individual cancers vary in their sensitivity to oncolytic viruses. In many cases this is due to differences in their production and response to interferons (IFNs). The experiments described here compared the responses of head and neck squamous cell carcinoma cell lines to two IFN subtypes, IFN-α2a and IFN-β, in protection from oncolytic vesicular stomatitis virus. We found that IFN-α2a was significantly less protective for cancer cells than was IFN-β, whereas normal cells were equivalently protected by both IFNs. These results suggest that from a therapeutic standpoint, selectivity for cancer versus normal cells may be enhanced by pairing VSV with IFN-α2a.

IPS-1 differentially induces TRAIL, BCL2, BIRC3 and PRKCE in type I interferons-dependent and -independent anticancer activity

RIG-I-like receptors are the key cytosolic sensors for RNA viruses and induce the production of type I interferons (IFN) and pro-inflammatory cytokines through a sole adaptor IFN-β promoter stimulator-1 (IPS-1) (also known as Cardif, MAVS and VISA) in antiviral innate immunity. These sensors also have a pivotal role in anticancer activity through induction of apoptosis. However, the mechanism for their anticancer activity is poorly understood. Here, we show that anticancer vaccine adjuvant, PolyIC (primarily sensed by MDA5) and the oncolytic virus, Newcastle disease virus (NDV) (sensed by RIG-I), induce anticancer activity. The ectopic expression of IPS-1 into type I IFN-responsive and non-responsive cancer cells induces anticancer activity. PolyIC transfection and NDV infection upregulate pro-apoptotic gene TRAIL and downregulate the anti-apoptotic genes BCL2, BIRC3 and PRKCE. Furthermore, stable knockdown of IPS-1, IRF3 or IRF7 in IFN-non-responsive cancer cells show reduced anticancer activity by suppressing apoptosis via TRAIL and anti-apoptotic genes. Collectively, our study shows that IPS-1 induces anticancer activity through upregulation of pro-apoptotic gene TRAIL and downregulation of the anti-apoptotic genes BCL2, BIRC3 and PRKCE via IRF3 and IRF7 in type I IFN-dependent and -independent manners.

The duality of chemokines in heart failure

The failing human heart is a bustling network of intra- and inter-cellular signals and related processes attempting to coordinate a repair mechanism for the injured or diseased myocardium. While our understanding of signaling by mode of cytokines is well understood on a systemic level, we are only now coming to elucidate the role of cytokines in cardiac self-regulation. An increasing number of studies are showing now that cardiomyocytes themselves have not only the ability but also the mandate to produce signals, and play direct roles in how these signals are interpreted. One of the families of cytokines employed by distressed cardiac tissue are chemokines. By regulating the movement of pro-inflammatory cell types to sites of injury, we see now how the myocardium responds to stress. Herein we review the participation of these inflammatory mediators and explore the delicate balance between their protective roles and damaging functions.

Type I Interferon Receptor Expression in Human Pancreatic and Periampullary Cancer Tissue

OBJECTIVES

Interferons (IFNs) have several anticancer mechanisms. A number of clinical trials have been conducted regarding adjuvant IFN-α therapy in pancreatic cancer. Type I IFNs exert their effect via the type I IFN receptor (IFNAR-1, IFNAR-2c). The aims of the present study were to determine the type I IFN receptor expression in pancreatic and periampullary cancer tissues and to study its relation with clinicopathological factors.

METHODS

Receptor expression was determined by immunohistochemistry in paraffin-embedded cancer tissue of 47 pancreatic and 54 periampullary cancer patients.

RESULTS

The results demonstrated that 91.5% of the pancreatic tumors and 88.9% of the periampullary tumors showed expression of IFNAR-1, of which 23.4% and 13.0% were strongly positive, respectively. Regarding IFNAR-2c expression, 68.1% of the pancreatic tumors and 68.5% of the periampullary tumors were positive, of which 4.3% of the pancreatic tumors and none of the periampullary tumors had a strong expression. No statistically significant associations were found between type I IFN receptor expression and clinicopathological factors or survival.

CONCLUSIONS

Type I IFN receptors are expressed in pancreatic and periampullary cancer tissues although with great intertumoral and intratumoral variability. A small proportion of both tumors showed a strong expression of the IFNAR-1; only a very small percentage of the pancreatic tumors showed strong expression of the IFNAR-2c.

Potentials of interferon therapy in the treatment of pancreatic cancer

Pancreatic cancer is a highly aggressive malignancy with limited treatment options. To improve survival for patients with pancreatic cancer, research has focused on other treatment modalities like adding biological modulators such as type-I interferons (IFNs). Type I IFNs (ie, IFN-α/IFN-β) have antiproliferative, antiviral, and immunoregulatory activities. Furthermore, they are able to induce apoptosis, exert cell cycle blocking, and sensitize tumor cells for chemo- and radiotherapy. A few years ago in vitro, in vivo, and several clinical trials have been described regarding adjuvant IFN-α therapy in the treatment of pancreatic cancer. Some studies reported a remarkable increase in the 2- and 5-year survival. Unfortunately, the only randomized clinical trial did not show a significant increase in overall survival, although the increased median survival implicated that some patients in the experimental group benefited from the adjuvant IFN-α therapy. Furthermore, encouraging in vitro and in vivo data points to a possible role for adjuvant IFN therapy. However, up till now, the use of IFNs in the treatment of pancreatic cancer remains controversial. This review, therefore, aims to describe, based on the available data, whether there is a distinct role for IFN therapy in the treatment of pancreatic cancer.

Induction of a unique isoform of the NCOA7 oxidation resistance gene by interferon β-1b

We demonstrate that interferon (IFN)-β-1b induces an alternative-start transcript containing the C-terminal TLDc domain of nuclear receptor coactivator protein 7 (NCOA7), a member of the OXR family of oxidation resistance proteins. IFN-β-1b induces NCOA7-AS (alternative start) expression in peripheral blood mononuclear cells (PBMCs) obtained from healthy individuals and multiple sclerosis patients and human fetal brain cells, astrocytoma, neuroblastoma, and fibrosarcoma cells. NCOA7-AS is a previously undocumented IFN-β-inducible gene that contains only the last 5 exons of full-length NCOA7 plus a unique first exon (exon 10a) that is not found in longer forms of NCOA7. This exon encodes a domain closely related to an important class of bacterial aldo-keto oxido-reductase proteins that play a critical role in regulating redox activity. We demonstrate that NCOA7-AS is induced by IFN and LPS, but not by oxidative stress and exhibits, independently, oxidation resistance activity. We further demonstrate that induction of NCOA7-AS by IFN is dependent on IFN-receptor activation, the Janus kinase-signal transducers and activators of transcription (JAK-STAT) signaling pathway, and a canonical IFN-stimulated response element regulatory sequence upstream of exon 10a. We describe a new role for IFN-βs involving a mechanism of action that leads to an increase in resistance to inflammation-mediated oxidative stress.

Influence of type-I Interferon receptor expression level on the response to type-I Interferons in human pancreatic cancer cells

Pancreatic cancer is a highly aggressive malignancy with limited treatment options. Type-I interferons (e.g. IFN-α/-β) have several anti-tumour activities. Over the past few years, clinical studies evaluating the effect of adjuvant IFN-α therapy in pancreatic cancer yielded equivocal results. Although IFN-α and-β act via the type-I IFN receptor, the role of the number of receptors present on tumour cells is still unknown. Therefore, this study associated, for the first time, in a large panel of pancreatic cancer cell lines the effects of IFN-α/-β with the expression of type-I IFN receptors. The anti-tumour effects of IFN-α or IFN-β on cell proliferation and apoptosis were evaluated in 11 human pancreatic cell lines. Type-I IFN receptor expression was determined on both the mRNA and protein level. After 7 days of incubation, IFN-α significantly reduced cell growth in eight cell lines by 5–67%. IFN-β inhibited cell growth statistically significant in all cell lines by 43–100%. After 3 days of treatment, IFN-β induced significantly more apoptosis than IFN-α. The cell lines variably expressed the type-I IFN receptor. The maximal inhibitory effect of IFN-α was positively correlated with the IFNAR-1 mRNA (P < 0.05, r = 0.63), IFNAR-2c mRNA (P < 0.05, r = 0.69) and protein expression (P < 0.05, r = 0.65). Human pancreatic cancer cell lines variably respond to IFN-α and-β. The expression level of the type-I IFN receptor is of predictive value for the direct anti-tumour effects of IFN-α treatment. More importantly, IFN-β induces anti-tumour effects already at much lower concentrations, is less dependent on interferon receptor expression and seems, therefore, more promising than IFN-α.

Selective antitumor effect of neural stem cells expressing cytosine deaminase and interferon-beta against ductal breast cancer cells in cellular and xenograft models

Due to their inherent tumor-tropic properties, genetically engineered stem cells may be advantageous for gene therapy treatment of various human cancers, including brain, liver, ovarian, and prostate malignancies. In this study, we employed human neural stem cells (HB1.F3; hNSCs) transduced with genes expressing Escherichia coli cytosine deaminase (HB1.F3.CD) and human interferon-beta (HB1.F3.CD.IFN-β) as a treatment strategy for ductal breast cancer. CD can convert the prodrug 5-fluorocytosine (5-FC) to its active chemotherapeutic form, 5-fluorouracil (5-FU), which induces a tumor-killing effect through DNA synthesis inhibition. IFN-β also strongly inhibits tumor growth by the apoptotic process. RT-PCR confirmed that HB1.F3.CD cells expressed CD and HB1.F3.CD.IFN-β cells expressed both CD and IFN-β. A modified transwell migration assay showed that HB1.F3.CD and HB1.F3.CD.IFN-β cells selectively migrated toward MCF-7 and MDA-MB-231 human breast cancer cells. In hNSC-breast cancer co-cultures the viability of breast cancer cells which were significantly reduced by HB1.F3.CD or HB1.F3.CD.IFN-β cells in the presence of 5-FC. The tumor inhibitory effect was greater with the HB1.F3.CD.IFN-β cells, indicating an additional effect of IFN-β to 5-FU. In addition, the tumor-tropic properties of these hNSCs were found to be attributed to chemoattractant molecules secreted by breast cancer cells, including stem cell factor (SCF), c-kit, vascular endothelial growth factor (VEGF), and VEGF receptor 2. An in vivo assay performed using MDA-MB-231/luc breast cancer mammary fat pad xenografts in immunodeficient mice resulted in 50% reduced tumor growth and increased long-term survival in HB1.F3.CD and HB1.F3.CD.IFN-β plus 5-FC treated mice relative to controls. Our results suggest that hNSCs genetically modified to express CD and/or IFN-β genes can be used as a novel targeted cancer gene therapy.

Hope and fear for interferon: the receptor-centric outlook on the future of interferon therapy

After several decades of intense clinical research, the great promise of Type I interferons (IFN1) as the anticancer wonder drugs that could cure or, at the very least, curb the progression of various oncological diseases has regrettably failed to deliver. Severe side effects and low efficacy of IFN1-based pharmaceutics greatly limited use of these drugs and further reduced the enthusiasm of clinical oncologists for future optimization of IFN1-based therapeutic modalities. Incredibly, extensive clinical studies to assess the efficacy of IFN1 alone or in combination with other anticancer drugs have not been paralleled by an equal scope in defining the determinants that confer cell sensitivity or refractoriness to IFN1. Given that all effects of IFN1 on malignant and benign cells alike are mediated by its receptor, the mechanisms regulating these receptor cell surface levels should play a paramount role in shaping the magnitude and duration of IFN1-elicited effects. These mechanisms and their role in controlling IFN1 responses, as well as an ability of a growing tumor to commandeer these events, are the focus of our review. We postulate that activation of numerous signaling pathways leading to elimination of IFN1 receptor occurs in cancer cells and benign cells that contribute to tumor tissue. We further hypothesize that activation of these eliminative pathways enables the escape from IFN1-driven suppression of tumorigenesis and elicits the primary refractoriness of tumor to the pharmaceutical IFN1.

Structural and dynamic determinants of type I interferon receptor assembly and their functional interpretation

Type I interferons (IFNs) form a network of homologous cytokines that bind to a shared, heterodimeric cell surface receptor and engage signaling pathways that activate innate and adaptive immune responses. The ability of IFNs to mediate differential responses through the same cell surface receptor has been subject of a controversial debate and has important medical implications. During the past decade, a comprehensive insight into the structure, energetics, and dynamics of IFN recognition by its two-receptor subunits, as well as detailed correlations with their functional properties on the level of signal activation, gene expression, and biological responses were obtained. All type I IFNs bind the two-receptor subunits at the same sites and form structurally very similar ternary complexes. Differential IFN activities were found to be determined by different lifetimes and ligand affinities toward the receptor subunits, which dictate assembly and dynamics of the signaling complex in the plasma membrane. We present a simple model, which explains differential IFN activities based on rapid endocytosis of signaling complexes and negative feedback mechanisms interfering with ternary complex assembly. More insight into signaling pathways as well as endosomal signaling and trafficking will be required for a comprehensive understanding, which will eventually lead to therapeutic applications of IFNs with increased efficacy.

Cytokines in cancer immunotherapy

Cytokines are molecular messengers that allow the cells of the immune system to communicate with one another to generate a coordinated, robust, but self-limited response to a target antigen. The growing interest over the past two decades in harnessing the immune system to eradicate cancer has been accompanied by heightened efforts to characterize cytokines and exploit their vast signaling networks to develop cancer treatments. The goal of this paper is to review the major cytokines involved in cancer immunotherapy and discuss their basic biology and clinical applications. The paper will also describe new cytokines in pre-clinical development, combinations of biological agents, novel delivery mechanisms, and potential directions for future investigation using cytokines.

Stochastic receptor expression determines cell fate upon interferon treatment

Type I interferons trigger diverse biological effects by binding a common receptor, composed of IFNAR1 and IFNAR2. Intriguingly, while the activation of an antiviral state is common to all cells, antiproliferative activity and apoptosis affect only part of the population, even when cells are stimulated with saturating interferon concentrations. Manipulating receptor expression by different small interfering RNA (siRNA) concentrations reduced the fraction of responsive cells independent of the interferon used, including a newly generated, extremely tight-binding variant. Reduced receptor numbers increased 50% effective concentrations (EC(50)s) for alpha interferon 2 (IFN-α2) but not for the tight-binding variant. A correlation between receptor numbers, STAT activation, and gene induction is observed. Our data suggest that for a given cell, the response is binary (+/-) and dependent on the stochastic expression levels of the receptors on an individual cell. A low number of receptors suffices for antiviral response and is thus a robust feature common to all cells. Conversely, a high number of receptors is required for antiproliferative activity, which allows for fine-tuning on a single-cell level.

Present role and future potential of type I interferons in adjuvant therapy of high-risk operable melanoma

Few molecular therapeutic approaches have been so rigorously investigated in relation to the pathophysiology and outcome of human diseases as type I interferons. Historically, IFNs were discovered after the phenomenon of 'interference' was first described by Isaacs and Lindenmann in 1957, and for years IFNs (IFNalpha) were considered as potential "antiviral penicillins" until the broader spectrum of effects upon normal cell physiology, the natural and adaptive immune systems, and tumor growth and proliferation were described. Interferon beta (IFNbeta) was the second human gene after insulin to be cloned, and it codes for the first cytokine used to treat human malignancies. Despite the progress in understanding and treating cancer over the last 25 years, IFN alpha (IFNalpha) remains the most commonly used biologically active cytokine in the treatment of solid tumors, and for some like melanoma, the only successful agent. In this review we discuss the role of type I interferons in the pathophysiology and treatment of melanoma, with emphasis on the 22 years of work conducted at the University of Pittsburgh. We discuss potential mechanisms that partially explain the clinical benefit, and set the groundwork for building upon, the design of more effective treatments for this disease.

Type I interferons in the treatment of pancreatic cancer: mechanisms of action and role of related receptors

OBJECTIVE

We evaluated the role of type I interferons (IFNs) and IFN receptors in the regulation of cell growth in 3 human pancreatic adenocarcinoma cell lines (BxPC-3, MiaPaCa-2, and Panc-1).

BACKGROUND

Chemotherapy and radiotherapy have a marginal role in the management of pancreatic adenocarcinoma. The addition of IFN-alpha showed promising results in early clinical trials.

METHODS

Cell proliferation and apoptosis were evaluated by DNA measurement and DNA fragmentation, respectively. Type I IFN receptor (IFNAR-1 and IFNAR-2 subunits) was determined by quantitative RT-PCR and immunocytochemistry. Cell cycle distribution was evaluated by propidium iodide staining and flow-cytometric analysis.

RESULTS

The incubation with IFN-beta for 6 days showed a potent inhibitory effect on the proliferation of BxPC-3 (IC(50), 14 IU/mL) and MiaPaCa-2 (IC(50), 64 IU/mL). The inhibitory effect of IFN-beta was stronger than IFN-alpha in all 3 cell lines and mainly modulated by the stimulation of apoptosis, although cell cycle arrest was induced as well. The expression of the type I IFN receptors was significantly higher in BxPC-3 (the most sensitive cell line to IFN) and mainly localized on the membrane, whereas in Panc-1 (the most resistant cell line) about 60% to 70% of cells were negative for IFNAR-2c with a mainly cytoplasmic staining for IFNAR-2c.

CONCLUSION

The antitumor activity of IFN-beta is more potent than IFN-alpha in pancreatic cancer cell lines through the induction of apoptosis. Further studies should investigate in vivo whether the intensity and distribution of IFNAR-1 and IFNAR-2c may predict the response to therapy with IFN-alpha and IFN-beta in pancreatic cancer.

Complete remission of hepatocellular carcinoma with portal vein tumor thrombus and lymph node metastases by arterial infusion of 5-fluorouracil and interferon-alpha combination therapy following hepatic resection

We report two cases of hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT) and lymph node (LN) metastases successfully treated by hepatic arterial infusion of 5-fluorouracil (5-FU) combined with systemic injection of interferon (IFN)-alpha following hepatic resection for the liver tumor. Complete remission was obtained. Case 1 was a 51-year-old man who had HCC in the right lobe of the liver with PVTT and multiple intrahepatic metastases. He also had abdominal and mediastinal LN metastases. Case 2 was a 53-year-old man who had diffuse-type HCC in the right lobe of the liver with PVTT and intrahepatic metastases. A chest computed tomography scan revealed lymph nodes enlarged to 1.0 cm from the mediastinum to the left supraclavicular space. Both patients underwent the hepatectomy to reduce the tumor volumes and remove the PVTT to relieve portal vein obstruction. Following the surgery, the patients underwent IFN-alpha/5-FU combination therapy. Three months after this combined therapy, tumor markers (both alpha-fetoprotein and protein induced by vitamin K absence or antagonist II) returned to the normal range and residual tumors in the liver disappeared. The patients are alive without any recurrence more than 1 year after initial treatment. IFN-alpha/5-FU combined therapy following hepatic resection is a promising modality for the treatment of advanced HCC with LN metastasis.

An interferon alpha2 mutant optimized by phage display for IFNAR1 binding confers specifically enhanced antitumor activities

All alpha-interferons (IFNalpha) bind the IFNAR1 receptor subunit with low affinity. Increasing the binding affinity was shown to specifically increase the antiproliferative potency of IFNalpha2. Here, we constructed a phage display library by randomizing three positions on IFNalpha2 previously shown to confer weak binding to IFNAR1. The tightest binding variant selected, comprised of mutations H57Y, E58N, and Q61S (YNS), was shown to bind IFNAR1 60-fold tighter compared with wild-type IFNalpha2, and 3-fold tighter compared with IFNbeta. Binding of YNS to IFNAR2 was comparable with wild-type IFNalpha2. The YNS mutant conferred a 150-fold higher antiproliferative potency in WISH cells compared with wild-type IFNalpha2, whereas its antiviral activity was increased by only 3.5-fold. The high antiproliferative activity was related to an induction of apoptosis, as demonstrated by annexin V binding assays, and to specific gene induction, particularly TRAIL. To determine the potency of the YNS mutant in a xenograft cancer model, we injected it twice a week to nude mice carrying transplanted MDA231 human breast cancer cells. After 5 weeks, no tumors remained in mice treated with YNS, whereas most mice treated with wild-type IFNalpha2 showed visible tumors. Histological analysis of these tumors showed a significant anti-angiogenic effect of YNS, compared with wild-type IFNalpha2. This work demonstrates the application of detailed biophysical understanding in the process of protein engineering, yielding an interferon variant with highly increased biological potency.

Interferon alpha receptors are important for antiproliferative effect of interferon-alpha against human hepatocellular carcinoma cells

AIM

Interferon (IFN)-alpha is a promising drug for the prevention and treatment of hepatocellular carcinoma (HCC). We reported that responders to IFN-alpha/5-fluorouracil combination therapy expressed higher IFN alpha receptor (IFNAR)2 in tumor. Herein we studied involvement of IFNARs in response to IFN-alpha in HCC cells.

METHODS

IFN-alpha sensitivity and expression of IFNARs were studied in six HCC cell lines (HuH7, PLC/PRF/5, HLE, HLF, HepG2, Hep3B) using growth-inhibitory and RT-PCR, Western blot assays. Short interfering RNAs (SiRNAs) against IFNAR1 and 2 were used to analyze the role of the IFNARs in IFN-alpha's effect and signal transduction.

RESULTS

The expressions of IFNAR1 and 2c mRNAs were higher in PLC/PRF/5 cells than those in other cell lines, and PLC/PRF/5 cells expressed abundant IFNAR2c on their cell membrane. When we examined the sensitivity of the HCC cell lines to the growth-inhibitory effect of IFN-alpha, PLC/PRF/5 exhibited a significant response, while the other cells were much more resistant. Knockdown of either IFNAR1 or 2 using siRNAs suppressed the IFN-alpha's signal transduction (2.5-fold), and decreased the growth-inhibitory effect (down by 69.9% and 67.3%).

CONCLUSION

The results suggest that the expression of IFNAR1 and IFNAR2c independently are important for the antiproliferative effect of IFN-alpha in HCC cells.

Potent inhibitory effects of type I interferons on human adrenocortical carcinoma cell growth

CONTEXT

Adrenocortical carcinoma (ACC) is a rare tumor with a poor prognosis. Despite efforts to develop new therapeutic regimens for metastatic ACC, surgery remains the mainstay of treatment. Interferons are known to exert tumor-suppressive effects in several types of human cancer.

DESIGN

We evaluated the tumor-suppressive effects of type I interferons (IFN)-alpha2b and IFNbeta on the H295 and SW13 human ACC cell lines.

RESULTS

As determined by quantitative RT-PCR analysis and immunocytochemistry, H295 and SW13 cells expressed the active type I IFN receptor (IFNAR) mRNA and protein (IFNAR-1 and IFNAR-2c subunits). Both IFNalpha2b and IFNbeta1a significantly inhibited ACC cell growth in a dose-dependent manner, but the effect of IFNbeta1a (IC50 5 IU/ml, maximal inhibition 96% in H295; IC50 18 IU/ml, maximal inhibition 85% in SW13) was significantly more potent, compared with that of IFNalpha2b (IC50 57 IU/ml, maximal inhibition 35% in H295; IC50 221 IU/ml, maximal inhibition 60% in SW13). Whereas in H295 cells both IFNs induced apoptosis and accumulation of the cells in S phase, the antitumor mechanism in SW13 cells involved cell cycle arrest only. Inhibitors of caspase-3, caspase-8, and caspase-9 counteracted the apoptosis-inducing effect by IFNbeta1a in H295 cells. In H295 cells, IFNbeta1a, but not IFNalpha2b, also strongly suppressed the IGF-II mRNA expression, an important growth factor and hallmark in ACC.

CONCLUSIONS

IFNbeta1a is much more potent than IFNalpha2b to suppress ACC cell proliferation in vitro by induction of apoptosis and cell cycle arrest. Further studies are required to evaluate the potency of IFNbeta1a to inhibit tumor growth in vivo.

Functional expression of human type I interferon receptors in the mouse liver

We expressed human type I interferon (IFN) receptors (IFNAR) in mice and investigated their signaling. Using a hydrodynamics-based delivery method, vectors containing the genes for IFNAR1 and IFNAR2 were transferred into mice. Six hours after gene-transfer, mice were intravenously injected with human IFN-alpha at 10,000 IU. IFNAR1 and IFNAR2 were both expressed in the liver, but not spleen or lung. The receptors were coexpressed in single liver cells. One hour after IFN-alpha injection, the phosphorylation status of signal transducer and activator of transcription factor 1 (STAT1), a key molecule of IFN signaling, was determined. Phosphotyrosine-STAT1 (p-STAT1), localized to the nucleus of IFNAR-expressing cells, was increased in the livers of IFNAR gene-transferred mice but not in control vector-transferred animals. In conclusion, functional human IFNAR can be delivered to the mouse liver, resulting in an increase in p-STAT1 levels following human IFN-alpha stimulation.

A novel modification of a flow cytometric assay of phosphorylated STAT1 in whole blood lymphocytes for rapid detection of interferon-α signal in vivo

Phosphorylation of signal transducer and activator of transcription factor 1 (STAT1) is a key response in the type I interferon (IFN) signal cascade. We developed a novel flow cytometric assay for phosphotyrosine-STAT1 (p-STAT1) to rapidly monitor in vivo IFN signaling. Mouse blood stimulated with mouse IFN-alpha was hemolyzed with lysis buffer in place of lymphocyte purification, permeabilized with methanol, and stained with an Alexa Fluor 488-conjugated anti-p-STAT1 antibody. The cells were also stained with phycoerythrin (PE)-conjugated anti-CD45 antibody for eliminating debris (CD45-negative) from leukocytes (CD45-positive), and with PE covalently linked to cyanin 5-conjugated anti-Gr-1 antibody for separating lymphocytes (Gr-1-negative) and granulocytes (Gr-1-positive). When whole blood was treated with IFN-alpha, the Alexa Fluor 488 intensity of lymphocytes increased, reaching a peak within 1 h, and this increase was statistically significant at IFN-alpha concentrations of 100 U/mL and higher. When IFN-alpha was administered intravenously to mice, the Alexa Fluor 488 intensity of blood lymphocytes was increased, reaching a peak in 1 h and returning to baseline at 18 h, and this increase was dose-dependent, with statistically significant increases seen at doses of 1,000 U/body and higher. The kinetics and dose-responses of p-STAT1 levels in the spleen, lung, and liver were similar to those in blood lymphocytes. This new flow cytometric assay of p-STAT1 in peripheral blood leukocytes will be useful for examining IFN-alpha signaling and for monitoring tissue response to IFN-alpha in vivo.

Inquiring into the differential action of interferons (IFNs): an IFN-alpha2 mutant with enhanced affinity to IFNAR1 is functionally similar to IFN-beta

Alpha and beta interferons (IFN-alpha and IFN-beta) are multifunctional cytokines that exhibit differential activities through a common receptor composed of the subunits IFNAR1 and IFNAR2. Here we combined biophysical and functional studies to explore the mechanism that allows the alpha and beta IFNs to act differentially. For this purpose, we have engineered an IFN-alpha2 triple mutant termed the HEQ mutant that mimics the biological properties of IFN-beta. Compared to wild-type (wt) IFN-alpha2, the HEQ mutant confers a 30-fold higher binding affinity towards IFNAR1, comparable to that measured for IFN-beta, resulting in a much higher stability of the ternary complex as measured on model membranes. The HEQ mutant, like IFN-beta, promotes a differentially higher antiproliferative effect than antiviral activity. Both bring on a down-regulation of the IFNAR2 receptor upon induction, confirming an increased ternary complex stability of the plasma membrane. Oligonucleotide microarray experiments showed similar gene transcription profiles induced by the HEQ mutant and IFN-beta and higher levels of gene induction or repression than those for wt IFN-alpha2. Thus, we show that the differential activities of IFN-beta are directly related to the binding affinity for IFNAR1. Conservation of the residues mutated in the HEQ mutant within IFN-alpha subtypes suggests that IFN-alpha has evolved to bind IFNAR1 weakly, apparently to sustain differential levels of biological activities compared to those induced by IFN-beta.