Interferon-alpha: regulatory effects on cell cycle and angiogenesis

The molecular mechanism responsible for HbSC retinopathy may depend on the action of the angiogenesis-related genes ROBO1 and SLC38A5

HbSC disease, a less severe form of sickle cell disease, affects the retina more frequently and patients have higher rates of proliferative retinopathy that can progress to vision loss. This study aimed to identify differences in the expression of endothelial cell-derived molecules associated with the pathophysiology of proliferative sickle cell retinopathy (PSCR). RNAseq was used to compare the gene expression profile of circulating endothelial colony-forming cells from patients with SC hemoglobinopathy and proliferative retinopathy (n = 5), versus SC patients without retinopathy (n = 3). Real-time polymerase chain reaction (qRT-PCR) was used to validate the RNAseq results. A total of 134 differentially expressed genes (DEGs) were found. DEGs were mainly associated with vasodilatation, type I interferon signaling, innate immunity and angiogenesis. Among the DEGs identified, we highlight the most up-regulated genes ROBO1 (log2FoldChange = 4.32, FDR = 1.35E-11) and SLC38A5 (log2FoldChange = 3.36 FDR = 1.59E-07). ROBO1, an axon-guided receptor, promotes endothelial cell migration and contributes to the development of retinal angiogenesis and pathological ocular neovascularization. Endothelial SLC38A5, an amino acid (AA) transporter, regulates developmental and pathological retinal angiogenesis by controlling the uptake of AA nutrient, which may serve as metabolic fuel for the proliferation of endothelial cells (ECs) and consequent promotion of angiogenesis. Our data provide an important step towards elucidating the molecular pathophysiology of PSCR that may explain the differences in ocular manifestations between individuals with hemoglobinopathies and afford insights for new alternative strategies to inhibit pathological angiogenesis.

Investigating underlying molecular mechanisms, signaling pathways, emerging therapeutic approaches in pancreatic cancer

Pancreatic adenocarcinoma, a clinically challenging malignancy constitutes a significant contributor to cancer-related mortality, characterized by an inherently poor prognosis. This review aims to provide a comprehensive understanding of pancreatic adenocarcinoma by examining its multifaceted etiologies, including genetic mutations and environmental factors. The review explains the complex molecular mechanisms underlying its pathogenesis and summarizes current therapeutic strategies, including surgery, chemotherapy, and emerging modalities such as immunotherapy. Critical molecular pathways driving pancreatic cancer development, including KRAS, Notch, and Hedgehog, are discussed. Current therapeutic strategies, including surgery, chemotherapy, and radiation, are discussed, with an emphasis on their limitations, particularly in terms of postoperative relapse. Promising research areas, including liquid biopsies, personalized medicine, and gene editing, are explored, demonstrating the significant potential for enhancing diagnosis and treatment. While immunotherapy presents promising prospects, it faces challenges related to immune evasion mechanisms. Emerging research directions, encompassing liquid biopsies, personalized medicine, CRISPR/Cas9 genome editing, and computational intelligence applications, hold promise for refining diagnostic approaches and therapeutic interventions. By integrating insights from genetic, molecular, and clinical research, innovative strategies that improve patient outcomes can be developed. Ongoing research in these emerging fields holds significant promise for advancing the diagnosis and treatment of this formidable malignancy.

Immunotherapy in Gastroenteropancreatic Neuroendocrine Neoplasia

The worldwide prevalence and incidence of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) and of NENs, in general, have been increasing recently. While valuing the considerable progress made in the treatment strategies for GEP-NEN in recent years, patients with advanced, metastasized disease still have a poor prognosis, which calls for urgent novel therapies. The immune system plays a dual role: both host-protecting and "tumor-promoting." Hence, immunotherapy is potentially a powerful weapon to help NEN patients. However, although recent successes with checkpoint inhibitors have shown that enhancing antitumor immunity can be effective, the dynamic nature of the immunosuppressive tumor microenvironment presents significant hurdles to the broader application of these therapies. Studies led to their approval in NEN of the lung and Merkel cell carcinoma, whereas results in other settings have not been so encouraging. Oncolytic viruses can selectively infect and destroy cancer cells, acting as an in situ cancer vaccine. Moreover, they can remodel the tumor microenvironment toward a T cell-inflamed phenotype. Oncolytic virotherapy has been proposed as an ablative and immunostimulatory treatment strategy for solid tumors that are resistant to checkpoint inhibitors alone. Future efforts should focus on finding the best way to include immunotherapy in the GEP-NEN treatment scenario. In this context, this study aims at providing a comprehensive generalized review of the immune checkpoint blockade and the oncolytic virotherapy use in GEP-NENs that might improve GEP-NEN treatment strategies.

Efficacy, safety and unmet needs of evolving medical treatments for carcinoid syndrome

This review reports on the currently available medical treatment options for the control of symptoms due to carcinoid syndrome in patients with neuroendocrine tumors. The efficacy and adverse events (AEs) of approved drugs such as somatostatin analogues (SSA), telotristat ethyl (TE) and interferon-alpha, are reviewed. Somatostatin analogues remain the standard treatment of carcinoid syndrome based on the high expression of somatostatin receptors and the resulting inhibition of secretion of bioactive compounds; their use is associated with relatively mild AEs, involving mainly the gastrointestinal system, and being usually transient. Although dose escalation of SSA remains an unapproved option, it is clinically implemented to alleviate symptoms in refractory carcinoid syndrome and supported by the most recent guidelines. The side effects associated with the increased dose are in general mild and consistent with standard dose of SSA. Telotristat ethyl, an oral inhibitor of tryptophan hydroxylase, the rate-limiting enzyme in serotonin biosynthesis, represents a rather novel innovative treatment option in patients with carcinoid syndrome suffering from diarrhea and complements the standard therapy of SSA. Given the low toxicity profile, TE may be considered an early add-on treatment to SSA in patients with uncontrolled carcinoid syndrome. However, further prolonged follow-up of patients treated with TE may be needed to exclude potential AEs, such as liver toxicity or depressed mood, in patients with long-term treatment. Interferon alpha is a cytokine with direct inhibitory effect on hormone secretion and tumor cell proliferation and an approved therapy in carcinoid syndrome but is associated with significant AEs in the majority of the patients requiring frequently dose reduction. The finding of a more favorable tolerability of pegylated interferon needs to be confirmed in a prospective study.

The Interactions Between Cancer Stem Cells and the Innate Interferon Signaling Pathway

Interferons (IFNs) form a family of cytokines with pleiotropic effects that modulate the immune response against multiple challenges like viral infections, autoimmune diseases, and cancer. While numerous anti-tumor activities have been described for IFNs, IFNs have also been associated with tumor growth and progression. The effect of IFNs on apoptosis, angiogenesis, tumor cell immunogenicity, and modulation of immune cells have been largely studied; however, less is known about their specific effects on cancer stem cells (CSCs). CSCs constitute a subpopulation of tumor cells endowed with stem-like properties including self-renewal, chemoresistance, tumorigenic capacity, and quiescence. This rare and unique subpopulation of cells is believed to be responsible for tumor maintenance, metastatic spread, and relapse. Thus, this review aims to summarize and discuss the current knowledge of the anti- and pro-CSCs effects of IFNs and also to highlight the need for further research on the interplay between IFNs and CSCs. Importantly, understanding this interplay will surely help to exploit the anti-tumor effects of IFNs, specifically those that target CSCs.

The tumor immune microenvironment in gastroenteropancreatic neuroendocrine neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are a group of rare tumors that are increasing in prevalence. The complex tumor immune microenvironment (TIME) plays an important role in tumor development and the response to immunotherapy but is poorly understood. In this review, the components of the TIME are described in detail, including discussion about infiltrating immune cells, the immune checkpoint system, the cytokine and chemokine milieu, and immunomodulatory factors. Moreover, a comparison between TIMEs among different types of GEP-NENs and the interplay among the TIME, tumor cells, and the stromal microenvironment is described. Novel treatment options for GEP-NENs and potential biomarkers for the immune response are also characterized. We provide a comprehensive generalized review of the TIME that can inform GEP-NEN treatment strategies.

An update on the management of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PNETs) are a rare and heterogeneous group of neoplasia and differ in their clinical presentation, behavior, and prognosis based on both histological features and cancer stage at the time of diagnosis. Although small-sized tumors can be surgically resected, locally advanced and metastatic tumors confer a poor prognosis. In addition, only limited treatment options are available to the latter group of patients with PNETs, such as hormonal analogs, cytotoxic agents, and targeted therapy. In selected patients, liver-directed therapies are also used. As expected, clinicians taking care of these patients are challenged to develop an effective and comprehensive treatment strategy for their patients amid a wide variety of treatment modalities. Targeted therapy for PNETs is limited to sunitinib and everolimus. Presently, a number of clinical studies are ongoing to assess the efficacy of newer targeted agents alone and in combination with previous agents for the treatment of advanced PNETs. The authors reviewed the current treatment and also discussed the emerging agents and emphasized the need to identify biomarkers.

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.

Systemic Therapies for Advanced Gastrointestinal Carcinoid Tumors

Well-differentiated gastrointestinal neuroendocrine tumors (GINETs) tend to be slow growing, but treatment of advanced disease remains a challenge. Somatostatin analogues (SSAs) are considered standard therapy for carcinoid syndrome. SSAs delay tumor progression in advanced well-differentiated gastroenteropancreatic NETs. Cytotoxic chemotherapy and interferon play a limited role in the treatment of nonpancreatic GINETs. There is no standard approach to treatment of patients with disease progression. Identification of systemic agents with antitumor activity in advanced disease remains an unmet medical need. Enrollment to clinical trials is encouraged; potential therapeutic targets include the vascular endothelial growth factor and mammalian target of rapamycin signaling pathways.

GEP-NETs update: Biotherapy for neuroendocrine tumours

Neuroendocrine tumours (NETs) represent a less frequent and heterogeneous group of tumours, which has experienced, in recent years, a significant increase in effective therapeutic possibilities overcoming the disappointing results from chemotherapy. Initial improvements in treatment strategies came from somatostatin analogues (SSAs) that have widely demonstrated a significant improvement in symptomatic relief and tumour control growth by a complex mechanism of action over cell survival, angiogenesis and immunomodulation. Recent investigations have pointed out novel SSAs with a wider binding profile (pasireotide), chimeric molecules against somatostatin receptors and dopamine receptors and the combination with targeted agents, such as mTOR inhibitors or antiangiogenic agents. Immunotherapy is the second cornerstone in NET treatment and has been represented with interferon alpha for a long time, with a demonstrated activity on tumour and clinical response. Its less manageable adverse events have limited its usage. However, different checkpoints in immune system regulation have been effectively targeted in different solid tumours, and novel approaches are currently arising in NETs. In conclusion, biotherapy remains an active treatment strategy for initial approach in patients with NETs. Further investigation on patients' selection, molecular profiles, treatment sequence or combination and optimisation of current and novel biotherapy agents is required.

Type I IFNs as biomarkers in rheumatoid arthritis: towards disease profiling and personalized medicine

RA (rheumatoid arthritis) is a chronic rheumatic condition hallmarked by joint inflammation and destruction by self-reactive immune responses. Clinical management of RA patients is often hampered by its heterogeneous nature in both clinical presentation and outcome, thereby highlighting the need for new predictive biomarkers. In this sense, several studies have recently revealed a role for type I IFNs (interferons), mainly IFNα, in the pathogenesis of a subset of RA patients. Genetic variants associated with the type I IFN pathway have been linked with RA development, as well as with clinical features. Moreover, a role for IFNα as a trigger for RA development has also been described. Additionally, a type I IFN signature has been associated with the early diagnosis of RA and clinical outcome prediction in patients undergoing biological drug treatment, two challenging issues for decision-making in the clinical setting. Moreover, these cytokines have been related to endothelial damage and vascular repair failure in different autoimmune disorders. Therefore, together with chronic inflammation and disease features, they could probably account for the increased cardiovascular disease morbidity and mortality of these patients. The main aim of the present review is to provide recent evidence supporting a role for type I IFNs in the immunopathology of RA, as well as to analyse their possible role as biomarkers for disease management.

Capacity of wild-type and chemokine-armed parvovirus H-1PV for inhibiting neo-angiogenesis

Anti-angiogenic therapy has been recognized as a powerful potential strategy for impeding the growth of various tumors. However no major therapeutic effects have been observed to date, mainly because of the emergence of several resistance mechanisms. Among novel strategies to target tumor vasculature, some oncolytic viruses open up new prospects. In this context, we addressed the question whether the rodent parvovirus H-1PV can target endothelial cells. We show that cultures of human normal (HUVEC) and immortalized (KS-IMM) endothelial cells sustain an abortive viral cycle upon infection with H-1PV and are sensitive to H-1PV cytotoxicity. H-1PV significantly inhibits infected KS-IMM tumor growth. This effect may be traced back by the virus ability to both kill proliferating endothelial cells and inhibit VEGF production Recombinant H-1PV vectors can also transduce tumor cells with chemokines endowed with anti-angiogenesis properties, and warrant further validation for the treatment of highly vascularized tumors.

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.

Gastroenteropancreatic neuroendocrine tumors: update on therapeutics

OBJECTIVE

To review the available literature addressing the treatment of pancreatic neuroendocrine tumors (PNETs) and carcinoid tumors.

DATA SOURCES

Relevant literature was identified by a PubMed search (January 1977-December 2011) of English-language literature using the terms gastroenteropancreatic neuroendocrine tumor, pancreatic neuroendocrine, carcinoid, and pancreatic islet cell tumor.

STUDY SELECTION AND DATA EXTRACTION

All published studies and abstracts, as well as relevant consensus guidelines, evaluating the current literature about PNETs and carcinoid tumors were included.

DATA SYNTHESIS

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a genetically diverse group of complex malignancies with varying biological and clinical courses. Historically believed to be rare, recent epidemiologic data suggest their incidence is rising. Two of the most commonly diagnosed GEP-NETs are PNETs and carcinoid tumors. Both subtypes are well-differentiated tumors and present as low or intermediate grade. The systemic manifestations of PNETs and carcinoid tumors are diverse and are related to the secretion of affected hormones and biogenic amines. Surgical resection of localized disease remains the only curative option. However, the utility of this approach is limited because most patients are diagnosed with advanced disease. Recent advances have led to an improvement in outcomes in patients with PNETs and carcinoid tumors. This review describes traditional therapies as well as emerging strategies being investigated to help manage these cancers. Treatment of poorly differentiated GEP-NETs is beyond the scope of this review.

CONCLUSIONS

The advent of new therapies for PNETs and carcinoid tumors has introduced a paradigm shift in the management of this heterogeneous malignancy.

Microencapsulated mammalian cells for simultaneous production of VEGF165b and IFNα

Targeted and simultaneous delivery VEGF165b and IFN alpha in anti-angiogenic and other applications could offer several advantages. For this a system was design using artificial cell alginate-poly-L-lysine- alginate (APA) microcapsules. Result confirms the ability of this system for simultaneous production of these proteins for 28-days. The IFN alpha on a 3 days period increased from 8 ± 0.36 μg/ml at day 10 to 27 ± 2.4 μg/ml at day 16 and then dropped to 6.5 ± 0.5 μg/ml. The VEGF165b on a 3 days period increased from 2.7 ± 0.7 μg/ml at day 10 to 6.9 ± 1 μg/ml at day 16.

Targeting the endothelin axis with atrasentan, in combination with IFN-alpha, in metastatic renal cell carcinoma

Background:

The endothelin system is involved in tumour growth. Atrasentan, a selective endothelin-A-receptor antagonist, blocks endothelin signalling. This phase I trial studied combining treatment of interferon-alpha (IFN-α) with atrasentan in renal cell carcinoma (RCC).

Patients and methods:

This study evaluated the safety and tolerance of IFN-α (9MU subcutaneously (s.c.) three times a week) in combination with atrasentan (2.5, 5 and 10 mg orally once daily) in untreated metastatic RCC. Cohort 10 mg was extended to obtain insights in efficacy and pharmacodynamics.

Results:

Observed toxicities mainly consisted of known IFN-like toxicities (anorexia, chills, fever, fatigue and nausea), and of nasal congestion (associated to atrasentan). None of these toxicities were considered dose limiting. Cohort 10 mg was extended up to 32 patients; in a subset of patients treated according to the protocol (n=27), median overall survival (OS) was 17.3 months. One patient (3.1%) showed a partial response lasting 14.3 months. In an exploratory analysis, we observed that in the subset of patients with declining vascular endothelial growth factor (VEGF) levels (in combination with rising Endothelin-1 levels), median OS was 22.2 months compared with 2.2 months in patients with increasing VEGF levels.

Conclusion:

Combination treatment of IFN-α 9MU-α s.c. three times a week and atrasentan 10 mg once daily is tolerated. Clinical activity, especially OS, and biomarkers in our view warrant further studies targeting the endothelin axis.

Effect of interferon-alpha treatment on [68Ga-DOTA,Tyr3,Thre8]octreotide uptake in CA20948 tumors: a small-animal PET study

In peptide receptor radionuclide therapy of neuroendocrine tumors, improvements have been made by increasing the affinity for receptors and by protecting critical organs (e.g., kidneys). However, tumor parameters involved in radiopeptide uptake are still under investigation. Interferon-α (IFNα) is used as biotherapy for neuroendocrine tumors. Several mechanisms of action are described, but the potential effect of IFNα on tumor uptake of labeled peptide has not been studied in vivo yet.

METHODS

Twenty-six male CA20948 tumor-bearing Lewis rats were imaged before and during IFNα treatment using quantitative small-animal PET with [(68)Ga-DOTA,Tyr(3),Thre(8)]octreotide. Imaging was performed at days 0, 3, and 7. Animals were divided into 3 groups according to the treatment: control (injected daily with saline), half (4 d of IFNα treatment from day 0 to day 3, then saline), and full (7 d of IFNα). A daily dose of IFNα (1.5 mIU) was administered subcutaneously. Quantitative PET results are expressed as percentage injected dose per cm(3) and normalized to baseline (day 0) values. Tumor size was monitored by PET and caliper measurements.

RESULTS

Gross tumor uptake and tumor volumes increased in all groups over the 7-d period. On day 3, mean ± SD ratios to day 0 were 1.2 ± 0.2, 1.3 ± 0.5, and 1.2 ± 0.4, respectively, for control, half, and full groups. On day 7, respective values were 1.1 ± 0.2, 1.3 ± 0.6, and 1.5 ± 0.4. At day 3, a comparison among groups showed no statistically significant difference. At day 7, the full group showed a significantly higher ratio in activity concentration than the control group (P = 0.021). A good correlation was found between tumor volumes assessed by small-animal PET and caliper measurements (R = 0.89, P < 0.0001).

CONCLUSION

As expected, over a period of 7 d, both tumor volumes and radiopeptide uptake increased in all animals. However, the activity concentration increased significantly more at day 7 in animals treated for 7 d with IFNα, compared with controls. This is the first, to our knowledge, in vivo indication that IFNα is able to increase tumor uptake of the labeled analog in a small-animal model of neuroendocrine tumors. The mechanisms underlying this effect (flow, vascular permeability, receptor upregulation) remain unknown and need to be further investigated.

Advances in the therapy of gastroenteropancreatic-neuroendocrine tumours (GEP-NETs)

Neuroendocrine tumours (NET) of the digestive tract comprise a broad range of malignancies. The therapeutic approach to these tumours has not evolved as it did in other tumour types in the last two decades. The deeper knowledge of the underlying molecular biology behind the growth of neuroendocrine cells has brought much information to light. We now know that somatostatin analogues may not only be considered as symptomatic treatment but also as antitumour agents. Sunitinib, a tyrosine kinase (TK) inhibitor with antiangiogenic and antitumoural properties, has been shown to induce significant improvement in progression-free survival in a randomised trial conducted in well-differentiated pancreatic islet-cell NETs. The relevance of the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway seems to be crucial in gastroenteropancreatic (GEP)-NETs. In fact, mTOR inhibitors have shown activity in uncontrolled trials, and large, randomised trial results will be available shortly. In this article, we summarise the most recent available data on medical therapy for GEPNETs.

Impairment of circulating endothelial progenitors in Down syndrome

BACKGROUND

Pathological angiogenesis represents a critical issue in the progression of many diseases. Down syndrome is postulated to be a systemic anti-angiogenesis disease model, possibly due to increased expression of anti-angiogenic regulators on chromosome 21. The aim of our study was to elucidate some features of circulating endothelial progenitor cells in the context of this syndrome.

METHODS

Circulating endothelial progenitors of Down syndrome affected individuals were isolated, in vitro cultured and analyzed by confocal and transmission electron microscopy. ELISA was performed to measure SDF-1α plasma levels in Down syndrome and euploid individuals. Moreover, qRT-PCR was used to quantify expression levels of CXCL12 gene and of its receptor in progenitor cells. The functional impairment of Down progenitors was evaluated through their susceptibility to hydroperoxide-induced oxidative stress with BODIPY assay and the major vulnerability to the infection with human pathogens. The differential expression of crucial genes in Down progenitor cells was evaluated by microarray analysis.

RESULTS

We detected a marked decrease of progenitors' number in young Down individuals compared to euploid, cell size increase and some major detrimental morphological changes. Moreover, Down syndrome patients also exhibited decreased SDF-1α plasma levels and their progenitors had a reduced expression of SDF-1α encoding gene and of its membrane receptor. We further demonstrated that their progenitor cells are more susceptible to hydroperoxide-induced oxidative stress and infection with Bartonella henselae. Further, we observed that most of the differentially expressed genes belong to angiogenesis, immune response and inflammation pathways, and that infected progenitors with trisomy 21 have a more pronounced perturbation of immune response genes than infected euploid cells.

CONCLUSIONS

Our data provide evidences for a reduced number and altered morphology of endothelial progenitor cells in Down syndrome, also showing the higher susceptibility to oxidative stress and to pathogen infection compared to euploid cells, thereby confirming the angiogenesis and immune response deficit observed in Down syndrome individuals.

The detrimental effects of IFN-α on vasculogenesis in lupus are mediated by repression of IL-1 pathways: potential role in atherogenesis and renal vascular rarefaction

Systemic lupus erythematosus (SLE) is characterized by increased vascular risk due to premature atherosclerosis independent of traditional risk factors. We previously proposed that IFN-α plays a crucial role in premature vascular damage in SLE. IFN-α alters the balance between endothelial cell apoptosis and vascular repair mediated by endothelial progenitor cells (EPCs) and myeloid circulating angiogenic cells (CACs). In this study, we demonstrate that IFN-α promotes an antiangiogenic signature in SLE and control EPCs/CACs, characterized by transcriptional repression of IL-1α and β, IL-1R1, and vascular endothelial growth factor A, and upregulation of IL-1R antagonist and the decoy receptor IL-1R2. IL-1β promotes significant improvement in the functional capacity of lupus EPCs/CACs, therefore abrogating the deleterious effects of IFN-α. The beneficial effects from IL-1 are mediated, at least in part, by increases in EPC/CAC proliferation, by decreases in EPC/CAC apoptosis, and by preventing the skewing of CACs toward nonangiogenic pathways. IFN-α induces STAT2 and 6 phosphorylation in EPCs/CACs, and JAK inhibition abrogates the transcriptional antiangiogenic changes induced by IFN-α in these cells. Immunohistochemistry of renal biopsies from patients with lupus nephritis, but not anti-neutrophil cytoplasmic Ab-positive vasculitis, showed this pathway to be operational in vivo, with increased IL-1R antagonist, downregulation of vascular endothelial growth factor A, and glomerular and blood vessel decreased capillary density, compared with controls. Our study introduces a novel putative pathway by which type I IFNs may interfere with vascular repair in SLE through repression of IL-1-dependent pathways. This could promote atherosclerosis and loss of renal function in this disease.

IRF9 is a key factor for eliciting the antiproliferative activity of IFN-alpha

A number of tumors are still resistant to the antiproliferative activity of human interferon (IFN)-alpha. The Janus kinases/Signal Transducers and Activators of Transcription (JAK-STAT) pathway plays an important role in initial IFN signaling. To enhance the antiproliferative activity of IFN-alpha, it is important to elucidate which factors in the JAK-STAT pathway play a key role in eliciting this activity. In human ovarian adenocarcinoma OVCAR3 cells sensitive to both IFN-alpha and IFN-gamma, only IFN regulatory factor 9 (IRF9)-RNA interference (RNAi) completely inhibited the antiproliferative activity of IFN-alpha among the intracellular JAK-STAT pathway factors. Conversely, Stat1-RNAi did not inhibit the antiproliferative activity of IFN-alpha, whereas it partially inhibited that of IFN-gamma. As a cell death pathway, it is reported that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis through TRAIL-receptor (R) 1 and TRAIL-R2. In IFN-alpha-treated OVCAR3 cells, IRF9-RNAi inhibited transcription of TRAIL whereas Stat1-RNAi did not, suggesting that the transcription of TRAIL induced by IFN-alpha predominantly required IRF9. Furthermore, IFN-stimulated response element-like motifs of TRAIL bound to IFN-stimulated gene factor 3 (ISGF3) complex after IFN-alpha treatment. Subsequently, TRAIL-R2-RNAi inhibited both antiproliferative activities of IFN-alpha and TRAIL, suggesting that TRAIL-R2 mediated both IFN-alpha and TRAIL signals to elicit their antiproliferative activities. Finally, IRF9 overexpression facilitated IFN-alpha-induced apoptosis in T98G (human glioblastoma multiforme) cells, which were resistant to IFN-alpha. Thus, this study suggests that IRF9 is the key factor for eliciting the antiproliferative activity of IFN-alpha and TRAIL may be one of the potential mediators.

Serum evaluation of soluble interferon-alpha/beta receptor and high-sensitivity C-reactive protein for diagnosis of the patients with gastrointestinal and hepatobiliary-pancreatic cancer

Serum soluble interferon-alpha/beta receptor (sIFN-alpha/betaR) and high-sensitivity C-reactive protein (hs-CRP) levels were evaluated in the patients with gastrointestinal and hepatobiliary-pancreatic cancer. We compared the sensitivity and specificity of serum sIFN-alpha/betaR with that of serum hs-CRP and evaluated the two diagnostic parameters in combination. Serum sIFN-alpha/betaR levels were measured in 92 patients and 25 healthy individuals by enzyme-linked immunosorbent assay. The diagnoses were 37 cases of hepatocellular carcinoma, 17 cases of pancreatic cancer, 15 cases of colon cancer, 13 cases of biliary tract cancer, and 10 cases of gastric cancer. Serum levels of sIFN-alpha/betaR and hs-CRP were significantly higher in the patients than in healthy individuals (p<0.05). The optimal cut-off values of sIFN-alpha/betaR and hs-CRP were 3600pg/ml and 0.5microg/ml, respectively. The sensitivity and specificity for these thresholds were 94.6% and 88.0%, whereas positive predictive and negative predictive values were 96.7% and 81.5%. These results suggest that a combination of serum sIFN-alpha/betaR and hs-CRP thresholds may be more reliable diagnostic parameter for gastrointestinal and hepatobiliary-pancreatic cancer.

Identification of interferon-beta-stimulated genes that inhibit angiogenesis in vitro

Interferons (IFNs) have proven antitumor activity against a variety of human malignancies, which may result, at least in part, from inhibition of angiogenesis. The objective of this study was to identify IFN-stimulated genes (ISGs) that played a role in mediation of angiogenic inhibition. IFN-beta was a more potent antiangiogenic agent compared to IFN-alpha2b (80% versus 20%, respectively) and suggests that IFNs inhibited angiogenesis by preventing endothelial cell differentiation, and not by direct antiproliferative effects. To identify ISGs that were key inhibitors of angiogenesis, we utilized an in vitro fibrin gel angiogenic assay which closely recapitulated the in vivo processes of angiogenesis. DNA microarray analysis of IFN-beta-treated endothelial cells in the fibrin gel assay identified 11 ISGs that were induced >10-fold during angiogenesis inhibition. Recombinant IP-10 inhibited angiogenesis in a dose-dependent fashion, but was a less effective inhibitor compared to IFN-beta, suggesting that additional ISGs are involved in inhibiting angiogenesis. ISG20 was upregulated by microarray analysis, but did not inhibit angiogenesis when overexpressed in human umbilical vein endothelial cells (HUVECs). However, a dominant negative mutant of ISG20 inhibited angiogenesis by 43%. Results suggest that IFN-induced angiogenic inhibition was likely mediated by multiple ISGs; our novel finding is that decreased exonuclease activity in HUVECs associated with expression of the ISG20 ExoII mutant inhibited angiogenesis.

Types I and II interferons upregulate the costimulatory CD80 molecule in monocytes via interferon regulatory factor-1

CD80/B7.1 expressed on monocytes plays a prominent role in the activation of T cell-mediated immunity and its level is reduced in monocytes from cancer patients. Type I (alpha/beta) and type II (gamma) IFNs are widely administered as adjuvant therapy. We show here that both classes of IFNs upregulate CD80 mRNA and protein in primary monocytes ex vivo. The stimulatory action of IFN-alpha/beta on CD80 is accompanied by the activation of both interferon regulatory factors IRF-1 and IRF-7, whereas IFN-gamma stimulating effect is associated only with IRF-1 induction. IFNs concomitantly upregulate the transcription of CD40 costimulatory molecule whose activation is known to require IRF-1. In monocytic U937 cells, IRF-1 is activated by IFN-gamma but not by IFN-alpha/beta, whereas it is the reverse for IRF-7; in the latter cells, only IFN-gamma is capable of stimulating CD80 transcription emphasizing the essential role of IRF-1. Moreover, siRNA against IRF-1 prevents IFN-gamma-mediated CD80 activation. In AML cells, IFNs upregulate CD40, CD80 and IRF-1 in the FAB-M4/M5 subtypes but not in the less differentiated M1/M2 subtypes. Monitoring the expression of CD80 on AML cells and its modulation by IFNs could help to predict the patients more susceptible to benefit from therapeutic strategies aimed at eliciting specific T cell responses to leukemia-associated antigens.

Signal transducer and activator of transcription 1 (STAT1) is essential for chromium silencing of gene induction in human airway epithelial cells

Hexavalent chromium (Cr(VI)) promotes lung injury and pulmonary diseases through poorly defined mechanisms that may involve the silencing of inducible protective genes. The current study investigated the hypothesis that Cr(VI) actively signals through a signal transducer and activator of transcription 1 (STAT1)-dependent pathway to silence nickel (Ni)-induced expression of vascular endothelial cell growth factor A (VEGFA), an important mediator of lung injury and repair. In human bronchial airway epithelial (BEAS-2B) cells, Ni-induced VEGFA transcription by stimulating an extracellular regulated kinase (ERK) signaling cascade that involved Src kinase-activated Sp1 transactivation, as well as increased hypoxia-inducible factor-1 alpha (HIF-1 alpha) stabilization and DNA binding. Ni-stimulated ERK, Src, and HIF-1 alpha activities, as well as Ni-induced VEGFA transcript levels were inhibited in Cr(VI)-exposed cells. We previously demonstrated that Cr(VI) stimulates STAT1 to suppress VEGFA expression. In BEAS-2B cells stably expressing STAT1 short hairpin RNA, Cr(VI) increased VEGFA transcript levels and Sp1 transactivation. Moreover, in the absence of STAT1, Cr(VI), and Ni coexposures positively interacted to further increase VEGFA transcripts. This study demonstrates that metal-stimulated signaling cascades interact to regulate transcription and induction of adaptive or repair responses in airway cells. In addition, the data implicate STAT1 as a rate limiting mediator of Cr(VI)-stimulated gene regulation and suggest that cells lacking STAT1, such as many tumor cell lines, have opposite responses to Cr(VI) relative to normal cells.

Interferon-related transcriptome alterations in the cerebrospinal fluid cells of Aicardi-Goutières patients

Aicardi-Goutières syndrome (AGS) is a rare interferon (IFN)-related encephalopathy with onset during the first year of life. AGS, is clinically characterized by progressive microcephaly, bilateral basal ganglia calcification, cerebral atrophy, cerebrospinal fluid (CSF), lymphocytosis, delayed development of psychomotor abilities with pyramidal-extrapyramidal syndrome and mimics congenital viral infections. Microarray analysis examining the expression of 18 880 human genes has been applied to the CSF lymphocytes of 20 AGS cases (age 4.5 +/- 4.4 years, mean +/- standard deviation) characterized by high IFN-alpha levels in CSF and 20 matched controls (age 4.4 +/- 4.3 years, mean +/- standard deviation). Gene-expression data reveal significant differences between AGS cases and controls for all controls and 18 AGS cases. The two AGS cases unclassified as compared with controls were both older than 7 years. AGS cases presented upregulation of genes involved in IFN-dependent pathways and lymphocyte functions, paralleled by the downregulation of genes encoding for angiopoietic activities. The cystatin F and DNAJ genes, having a negative feedback on IFN pathways, underwent a progressive age-related increase in their expression. These gene-expression signature parallels a progressive attenuation of clinical symptoms with age. Obtained results provide evidence that exposure to IFN-alpha is harmful for developing brain.

The role of leucocytes in the acetyl salicylic acid (aspirin) induced nitric oxide synthesis in the production of interferon-alpha, a potent inhibitor of platelet aggregation and a thrombolytic agent

The role of aspirin-induced NO synthesis in the production of interferon-alpha (IFN-alpha) in leucocytes and the effect of IFN-alpha on platelet aggregation was studied. Treatment of Platelet Rich Plasma (PRP) with the dialyzed supernatant from the leucocyte suspension incubated with 80 microM aspirin resulted in parallel syntheses of NO and IFN-alpha as determined by methemoglobin assay and enzyme linked immunosorbent assay respectively. Incubation of PRP with 10 nM purified IFN-alpha for 40 min resulted in the maximal inhibition of platelet aggregation through the synthesis of NO due to the activation of nitric oxide synthase in platelets by IFN-alpha. The treatment of clotted PRP with IFN-alpha resulted in the lysis of the clot due to the fibrinolysis. Injection of IFN-alpha was found to protect mice from death due to the lysis of ADP-induced coronary thrombus. Interferon-alpha was found to be a potent inhibitor of platelet aggregation and a thromboprotective agent.

IFN-alpha induces transcription of hypoxia-inducible factor-1alpha to inhibit proliferation of human endothelial cells

Expression of hypoxia-inducible factor (HIF)-1alpha, a transcription factor subunit increased by protein stabilization in response to hypoxia, is increased in human endothelial cells (ECs) by IFN-alpha under normoxic conditions. IFN-alpha increases HIF-1alpha transcript levels within 2 h by up to 50% and doubles HIF-1alpha protein expression. Based on pharmacological inhibition studies, the increase in HIF-1alpha mRNA involves new transcription, is independent of new protein synthesis, and requires JAK signaling. Protein knockdown by small interfering RNA confirms the involvement of JAK1 and TYK2, as well of IFN-stimulated gene factor 3 (ISGF3). IFN-gamma does not significantly induce HIF-1alpha mRNA, but increases the magnitude and duration of the IFN-alpha effect. IFN-alpha-induced HIF-1alpha protein translocates to the nucleus and can bind to hypoxia response elements in DNA. However, IFN-alpha treatment fails to induce transcription of several prototypic HIF-responsive genes (VEGF-A, PPARgamma, and prostacyclin synthase) due to an insufficient increase in HIF-1alpha protein levels. Although certain other HIF-responsive genes (PHD3 and VEGF-C) are induced following IFN-alpha and/or IFN-gamma treatment, these responses are not inhibited by siRNA knockdown of HIF-1alpha. Additionally, IFN-alpha induction of ISGF3-dependent genes involved in innate immunity (viperin, OAS2, and CXCL10) are also unaffected by knockdown of HIF-1alpha. Interestingly, knockdown of HIF-1alpha significantly reduces the capacity of IFN-alpha to inhibit endothelial cell proliferation. We conclude that IFN-alpha induces the transcription of HIF-1alpha in human endothelial cells though a JAK-ISGF3 pathway under normoxic conditions, and that this response contributes to the antiproliferative activity of this cytokine.

A novel tumor-promoting function residing in the 5' non-coding region of vascular endothelial growth factor mRNA

BACKGROUND

Vascular endothelial growth factor-A (VEGF) is one of the key regulators of tumor development, hence it is considered to be an important therapeutic target for cancer treatment. However, clinical trials have suggested that anti-VEGF monotherapy was less effective than standard chemotherapy. On the basis of the evidence, we hypothesized that vegf mRNA may have unrecognized function(s) in cancer cells.

METHODS AND FINDINGS

Knockdown of VEGF with vegf-targeting small-interfering (si) RNAs increased susceptibility of human colon cancer cell line (HCT116) to apoptosis caused with 5-fluorouracil, etoposide, or doxorubicin. Recombinant human VEGF165 did not completely inhibit this apoptosis. Conversely, overexpression of VEGF165 increased resistance to anti-cancer drug-induced apoptosis, while an anti-VEGF165-neutralizing antibody did not completely block the resistance. We prepared plasmids encoding full-length vegf mRNA with mutation of signal sequence, vegf mRNAs lacking untranslated regions (UTRs), or mutated 5'UTRs. Using these plasmids, we revealed that the 5'UTR of vegf mRNA possessed anti-apoptotic activity. The 5'UTR-mediated activity was not affected by a protein synthesis inhibitor, cycloheximide. We established HCT116 clones stably expressing either the vegf 5'UTR or the mutated 5'UTR. The clones expressing the 5'UTR, but not the mutated one, showed increased anchorage-independent growth in vitro and formed progressive tumors when implanted in athymic nude mice. Microarray and quantitative real-time PCR analyses indicated that the vegf 5'UTR-expressing tumors had up-regulated anti-apoptotic genes, multidrug-resistant genes, and growth-promoting genes, while pro-apoptotic genes were down-regulated. Notably, expression of signal transducers and activators of transcription 1 (STAT1) was markedly repressed in the 5'UTR-expressing tumors, resulting in down-regulation of a STAT1-responsive cluster of genes (43 genes). As a result, the tumors did not respond to interferon (IFN)alpha therapy at all. We showed that stable silencing of endogenous vegf mRNA in HCT116 cells enhanced both STAT1 expression and IFNalpha responses.

CONCLUSIONS

These findings suggest that cancer cells have a survival system that is regulated by vegf mRNA and imply that both vegf mRNA and its protein may synergistically promote the malignancy of tumor cells. Therefore, combination of anti-vegf transcript strategies, such as siRNA-based gene silencing, with anti-VEGF antibody treatment may improve anti-cancer therapies that target VEGF.

The fascinating but deceptive ferritin: to measure it or not to measure it in chronic kidney disease?

Although the emergence of erythropoiesis-stimulating agents has revolutionized the anemia management of chronic kidney disease (CKD) in the past two decades, strategies to assess iron (Fe) status and to provide Fe supplementation have remained indistinct. The reported cases of hemochromatosis in dialysis patients from the pre-erythropoiesis-stimulating agent era along with the possible associations of Fe with infection and oxidative stress have fueled the "iron apprehension." To date, no reliable marker of Fe stores in CKD has been agreed on. Serum ferritin continues to be the focus of attention. Almost half of all maintenance hemodialysis patients have a serum ferritin >500 ng/ml. In this ferritin range, Fe supplementation currently is not encouraged, although most reported hemochromatosis cases had a serum ferritin >2000 ng/ml. The moderate-range hyperferritinemia (500 to 2000 ng/ml) seems to be due mostly to non-Fe-related conditions, including inflammation, malnutrition, liver disease, infection, and malignancy. Recent epidemiologic studies have shown that a low, rather than a high, serum Fe is associated with a poor survival in maintenance hemodialysis patients. In multivariate adjusted models that mitigate the confounding effect of malnutrition-inflammation, serum ferritin <1200 ng/ml and Fe saturation ratio in 30 to 50% range are associated with the greatest survival in maintenance hemodialysis patients. Although ferritin is a fascinating molecule, moderate hyperferritinemia is a misleading marker of Fe stores in patients with CKD. It may be time to revisit the utility of serum ferritin in CKD and ask ourselves whether its measurement has helped us or has caused more confusion and controversy.

Toxicity as a result of immunostimulation by biologics

The immune system has evolved highly effective mechanisms of surveillance and defense against foreign pathogens, and is also thought to act in surveillance and suppression of cancer. Thus, a predominant goal of immune system-based therapies is to normalize or enhance the host immune response in the areas of infectious disease and oncology. This review considers general approaches used for therapeutic immunostimulation, alterations in immune response mechanisms that occur with these treatments and the syndromes that commonly arise as a result of these changes. Because nonclinical studies of these therapies are conducted in animal models as the basis for predicting potential human toxicities, this review also considers the value of nonclinical testing to predict human toxicity.

Bioavailability and tissular distribution of docetaxel, a P-glycoprotein substrate, are modified by interferon-alpha in rats

Interferon-alpha (IFN-alpha) inhibits intestinal P-glycoprotein (P-gp) expression in rats. In the present study, the effects of repeated pre-treatment with recombinant human INF-alpha (rhIFN-alpha) on oral and intravenous pharmacokinetics of a P-gp substrate, docetaxel (DTX; Taxotere) were investigated in a rat model. The bioavailability and distribution in different organs were also studied. Sprague-Dawley rats were subcutaneously pre-treated with either rhIFN-alpha for 8 days (4MIU kg(-1), once daily) or with pegylated-IFN-alpha (ViraferonPeg; 60 microg kg(-1), Days 1, 4 and 7). The rats were then distributed into sub-groups (n = 5-6) according to the pre-treatment type, and received one dose of [(14)C]DTX (20 mgkg(-1)) either orally or intravenously. Pharmacokinetics studies were then performed over 240 min, at the end of which tissues (intestine, liver, kidneys, lung, heart and brain) were immediately removed for radioactivity quantitation. Non-pegylated and pegylated IFN-alpha both increased DTX oral bioavailability parameters: C(max) (17.0+/-4.0 microg L(-1) (P < 0.02) and 18+/-5.5 microg L(-1) (P < 0.05), respectively, vs 7.4+/-2.5 microg L(-1) for the control) and AUC (0.036+/-0.010 microg h mL(-1) (P < 0.01) and 0.033+/-0.009 microg h mL(-1) (P < 0.01), respectively, versus 0.012+/-0.004 microg h mL(-1) for the control). IFN-alpha also delayed DTX absorption from 60 min in controls to about 95 min and 80 min in non-pegylated and pegylated treated animals, respectively. However, IFN-alpha did not affect intravenous DTX pharmacokinetics and it had a limited effect on tissue distribution at 240 min. [(14)C]DTX was decreased in intestine and enhanced in brain in both pre-treated groups. rhIFN-alpha modified the P-gp-dependent pharmacokinetics of DTX, limited its intestinal efflux and markedly enhanced its oral bioavailability.

Interferon alpha 2b treatment in an eleven-year-old boy with disseminated lymphangiomatosis

Disseminated lymphangiomatosis is a rare disease mostly observed in children and young adults. If no surgical removal can be achieved, the prognosis is poor, especially for patients with thoracic localization and pleural effusions. Next to pleural drainage, therapeutic options include radiotherapy, local, and systemic pharmacotherapy. An 11-year-old boy presented with disseminated lymphangiomatosis involving thorax with massive pleural effusions, retroperitoneum, and bones. In immunohistochemical analysis, the tissue biopsy stained positive for vascular endothelial growth factor-receptor 3 (VEGFR-3). The patient has been treated with interferon alpha 2b for 2 years, and achieved a good clinical and radiological response.

Inhibition of 12-lipoxygenase during baicalein-induced human lung nonsmall carcinoma H460 cell apoptosis

Baicalein is known as a 12-lipoxygenase (12-LOX) inhibitor. The 12-LOX is found to be involved in the progression of human cancers and the inhibitor of 12-LOX offers a target for the prevention cancer. We demonstrated the inhibitory effect of baicalein on the gene and protein expression of 12-LOX in H460 human lung nonsmall carcinoma cell line. Treatment of baicalein inhibited the growth of H460 cells in a dose-dependent manner. Following 24h exposure to 50muM baicalein, cell cycle analysis revealed an increase in the cell population in S-phase. During the S-phase arrest, baicalein decreased the protein levels of cdk1 and cyclin B1, which are the regulating proteins of S-phase transition to G2/M-phase, in this study. Furthermore, baicalein induced the most of H460 cell apoptosis after treatment for 48h. H460 cells formed vesicles and apoptotic body, and then floated after treatment with baicalein. Baicalein-induced H460 cell apoptosis was confirmed by DNA condensation and fragmentation. Baicalein-induced apoptosis were also accompanied by decreasing in Bcl-2 and proform of caspase-3 and increasing p53 and Bax protein levels. Pretreatment with a specific caspase-3 inhibitor, Ac-DEVD-CHO, partially reduced baicalein-induced cell death, indicating baicalein induces apoptosis is partially dependent on caspase-3 pathway in H460 cells. These data suggest that baicalein, a 12-LOX inhibitor, inhibits the proliferation of H460 cells via S-phase arrest and induces apoptosis in association with the regulation of molecules in the cell cycle and apoptosis-related proteins.

Distinct functions of IRF-3 and IRF-7 in IFN-alpha gene regulation and control of anti-tumor activity in primary macrophages

Type I IFN (IFN-alpha/beta) have important biological functions ranging from immune cell development and activation, to tumor cell killing and most importantly inhibition of virus replication. Following viral infection or activation of Toll-like receptors (TLRs) via distinct ligands, IFN-alpha/beta are produced. Two members of the interferon regulatory factor (IRF) family - IRF-3 and IRF-7 - are the major modulators of IFN gene expression. Activation of IRF-3 and IRF-7 by TBK1/IKKvarepsilon mediated phosphorylation promotes IFN gene expression and potentiates the production of IFN responsive genes important to the development of an effective antiviral immune response. IFN treatment can augment anti-tumor properties and they are potentially key players in cancer therapy. For example, adoptive transfer of IFN-gamma-activated macrophages can mediate tumor cell killing via direct cell-cell contact, as well as release of soluble cytotoxic pro-inflammatory molecules. A recent study investigated whether IRF-3 and IRF-7 could mediate the acquisition of new anti-tumor effector functions in macrophages. Adenovirus mediated transduction of the active form of IRF-7 into primary macrophages resulted in the production of type I IFN, upregulation of target genes including TRAIL and increased tumoricidal activity of macrophages; in contrast, the active form of IRF-3 led to induction of cell death. These studies indicate that IRF-7 transduced macrophages may be an attractive candidate for in vivo adoptive therapy of cancer.

Interferon-alpha and somatostatin analog in patients with gastroenteropancreatic neuroendocrine carcinoma: single agent or combination?

In most cases gastro-enteropancreatic neuroendocrine tumors grow slowly. Interferon-alpha and somatostatin analogs have shown symptomatic, biochemical, and, in a minority of cases, antiproliferative activity. Generally, they are proposed as single-agent therapy. However, based on in vitro and in vivo evidence, the combined use of these drugs was proposed in several non-randomized trials, indicating that there is an additive effect of the combination. Nevertheless, the three randomized trials published so far did not show a statistically significant survival benefit for the combination compared to the same agents alone, even though an advantage for the combination came out in all three studies. On the other hand, data from non-randomized trials would justify the sequential use of the two drugs or the combination after progression on single agent therapy. Therefore, at present the up-front combined use of interferon-alpha and somatostatin analog is not justified, whereas it could be indicated after progression to single-agent therapy. Further larger, international, prospective, randomized, multicentric clinical trials studying homogeneous populations would be necessary to give a final answer, but the rarity and heterogeneity of this malignancy does not assure that it will be possible.

Therapeutic options for gastrointestinal carcinoids

Although wide surgical resection is the optimal curative therapy for carcinoid tumors, in most patients the presence of metastatic disease at diagnosis usually renders excision a palliative procedure. This nevertheless decreases tumor burden, facilitates symptom control, and prevents complications caused by bleeding, perforation, or bowel obstruction resulting from fibrosis. In the stomach (types I and II) and rectum endoscopic excision may be adequate provided the lesion(s) are local. Long-term therapy is focused on symptom alleviation and improvement of quality of life using somatostatin analogues, particularly in a subcutaneous depot formulation. In some instances interferons may have a role but their usage often is associated with substantial adverse events. Conventional chemotherapy and external radiotherapy either alone or in a variety of permutations are of minimal efficacy and should be balanced against the decrease in quality of life often engendered by such agents. Hepatic metastases may be amenable to surgery, radiofrequency ablation, or embolization either alone or in combination with chemotherapeutic agents or isotopically loaded microspheres. Rarely hepatic transplantation may be of benefit although controversy exists as to its actual use. Peptide-receptor-targeted radiotherapy for advanced disease using radiolabeled octapeptide analogs (111In/90Yt/177Lu-octreotide) appear promising but data are limited and its status remains investigational. A variety of antiangiogenesis and growth factor-targeted agents have been evaluated, but as yet have shown little promise. The keystone of current therapy remains the long-acting somatostatin analogues that alleviate symptomatology and substantially improve quality of life with minimal adverse effects.

IFN-α1,8 Inhibits Tumor-Induced Angiogenesis in Murine Angiosarcomas

Interferon-alpha (IFN-alpha) has proved effective in the treatment of hemangiomas, hemangioblastomas, and Kaposi's sarcoma. To investigate the ability of IFNs to inhibit angiosarcoma, we used two transformed murine endothelial cell lines that form angiosarcomas in vivo. SVR and MS1-VEGF cell lines express oncogenic H-ras or vascular endothelial growth factor (VEGF), respectively. IFN-alpha1,8, which is active against murine and human cells, inhibited SVR and MS1-VEGF proliferation in vitro by 40% at 10(3) U/mL (p = 0.028). In vivo, IFN-alpha1,8 inhibited SVR tumor volume by 71% (p = 0.047) and MS1-VEGF volume by 79% (p = 0.003). Tumor-induced angiogenesis was decreased in SVR tumors by 52% (p = 0.005) and in MS1-VEGF tumors by 58% (p = 0.001). Sera from IFN-alpha1,8-treated mice bearing either SVR or MS1-VEGF tumors demonstrated a 5-fold increase in IP-10/CXCL10 (p = 0.001), an IFN-induced antiangiogenic protein. Both recombinant IP-10 and IFN-alpha1,8 inhibited human umbilical vein endothelial cell (HUVEC) vessel formation in the fibrin gel assay, a three-dimensional culture model of angiogenesis, by 56% at 25 ng/mL and 50% at 1.2 ng/mL, respectively (p < 0.001). An IP-10 blocking antibody restored vessel formation to 80% of untreated controls (p = 0.001). Given the magnitude of the in vivo response, these data suggested that the antitumor effects of IFN-alpha1,8 were likely mediated through angiogenesis inhibition rather than solely by direct inhibition of tumor cell proliferation.

Adenovirus delivery provides extended interferon-alpha exposure and augments treatment of metastatic carcinoma

Type I interferons (e.g. IFNalpha2b) have been successfully used to treat a variety of hematological malignancies, but have not been efficacious for treatment of most solid tumors. We tested the hypothesis that delivery of type I interferon utilizing recombinant adenovirus (rAd) vectors may improve treatment efficacy of metastatic carcinomas by providing increased interferon exposure resulting from continuous transgene expression. Treatment of mice with a rAd-vector expressing hybrid-IFN (rAd-IFNalpha2alpha1) inhibited 4T1 mammary carcinoma tumor growth and induced tumor regression in a dose-dependent manner. Moreover, rAd-IFNalpha2alpha1 treatment reduced hepatic and pulmonary metastatic burden. A comparison of local and systemic routes of administration demonstrated that intratumoral delivery of rAd-IFNalpha2alpha1 was sufficient for inhibition of tumor growth. Moreover, it reduced toxicity associated with high-dose systemic IFNalpha2alpha1 exposure. Interestingly, antitumor activity following intratumoral treatment was due, in part, to the immunostimulatory capacity of the rAd vector component. Furthermore, systemic administration of rAd-IFNalpha2alpha1 potentiated the immunotherapeutic effect induced by local intralesional delivery of empty-rAd vector. These results suggest continuous interferon-alpha exposure may provide improved antitumor responses for metastatic carcinomas. Additionally, immunostimulatory responses induced by rAd-IFNalpha2alpha1 may mitigate the immune-evasive tumor microenvironment.

Sorafenib: Scientific Rationales for Single-Agent and Combination Therapy in Clear-Cell Renal Cell Carcinoma

Clear-cell renal cell carcinoma (RCC) is characterized by the loss of von Hippel-Lindau disease protein and the resultant dysregulation of the vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR), platelet-derived growth factor-beta (PDGF-beta)/PDGF receptor-beta (PDGFR-beta), and transforming growth factor-alpha (TGF-alpha)/epidermal growth factor receptor (EGFR)/Raf pathways, which contribute to angiogenesis, lymphangiogenesis, and tumor cell growth and survival. Significant advances in the treatment of clear-cell RCC have been derived from agents that target these pathways, including the multiple-kinase inhibitors (MKIs) sorafenib, sunitinib, and AG013736, which target multiple VEGFRs as well as PDGFR-beta. Sorafenib has the added advantage of inhibiting multiple different Raf isoforms, which enables it to target TGF-alpha/EGFR signaling and may also enhance its inhibition of VEGFR and PDGFR-beta. This review will examine the recent advances in our understanding of the biology of clear-cell RCC and show how those advances have helped delineate new targets of opportunity for treatment. It will also present the early clinical results of agents that target the pathways dysregulated in clear-cell RCC, with special emphasis on sorafenib and the other active MKIs, and will describe the scientific rationales for ongoing and future sorafenib-based combination therapy trials in RCC.

The role of interferon-alpha in a successful murine tumor therapy

Combination therapy using reovirus type 3 and the chemo-therapeutic agent 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) is sufficient to cure approximately 80% of EL-4 lymphoma tumor-bearing BD2F1 male mice. Cured animals can be challenged with the EL-4 tumor, in the absence of the therapy, to yield 100% survival, whereas those challenged with heterologous tumor produce 0% survival. These results strongly suggest that a host-immune response is responsible for the observed therapeutic effect. Reovirus, a double-stranded RNA virus, is an efficient inducer of type I interferon. In an effort to determine the role of virus in this therapy, we substituted interferon-alpha (IFN-alpha) for reovirus in the therapy. Doses of IFN-alpha from 1000-10,000 U were capable of replacing reovirus to produce cure rates similar to reovirus. Spleen cells isolated from therapy-treated animals demonstrated high levels of cytotoxicity against the natural killer cell-sensitive cell line YAC-1, but not against EL-4 tumor. In vitro stimulation of isolated spleen cells by IFN-alpha resulted in a high level of natural killer cell activity, but no cytotoxicity against the EL-4 tumor. A significant antiproliferative effect against the EL-4 tumor in cell culture was demonstrated by IFN-alpha. Finally, therapy-treated, tumor-bearing mice that were injected with anti-IFN-alpha + -beta antibodies had similar survival levels as control mice, indicating that other cytokines might also play a role in promoting tumor killing. These investigations suggest that IFN-alpha may be a mediator of antitumor activity in the reovirus therapy system.

Efficient human interferon-alpha gene transfer to neuroendocrine tumor cells with long-term and stable expression

Interferon (IFN)-alpha has been used in the treatment of neuroendocrine (NE) tumors; however, the feasibility of IFN-alpha gene therapy has not been evaluated in NE tumor cells. In this study, human IFN-alpha2 (hIFN-alpha2) gene has been transferred into a NE tumor cell line BON. hIFN-alpha2-expressing BON cells were subcutaneously inoculated in nude mice. The results demonstrated that hIFN-alpha2 exerted significant antiproliferative effects on NE tumor cell lines (BON and LCC18) and other tumor cell lines (CA46 and SW480) as well as porcine aorta cell line. Furthermore, hIFN-alpha2 demonstrated its antineovascular activity in mice tumor and a direct antiangiogenic effect in chicken chorioallantoic membrane assay. hIFN-alpha2-expressing BON cells had a stable and long-term expression. Mice implanted with hIFN-alpha2-expressing BON cells showed a lower incidence, a delayed development and a significantly longer doubling time of the tumor compared to both wild-type (WT) and vector group. In addition, IFN-alpha significantly inhibited cell adhesion of WT BON cells. hIFN-alpha2-expressing BON tumors had a high level of hIFN-alpha2 protein. Finally, mice implanted with a mixture of WT and hIFN-alpha2-expressing BON cells (1:1) presented a delayed tumor development and had an even lower incidence of tumors than those implanted with hIFN-alpha2-expressing BON cells only. The doubling time of tumor was also longest in the mixture group. Our data suggest that hIFN-alpha2 gene therapy might be possible to be used as a new treatment for NE tumor patients. Further studies on the regulation of hIFN-alpha expression are needed, especially in combination with other cytokines, which could lead to a better understanding and improvements of hIFN-alpha gene therapy.