Adenovirus-mediated gene transfer of interferon alpha improves dimethylnitrosamine-induced liver cirrhosis in rat model

Canine interferon lambda 3 expressed using an adenoviral vector effectively induces antiviral activity against canine influenza virus

Interferon-lambda (IFN-λ) is a type-III IFN and is considered a candidate of antiviral therapeutics. Although the antiviral effects of IFN-λ have been investigated in several studies, it has not been clinically approved as an antiviral agent. In this study, an adenoviral vector expression system employing a tetracycline-operator system was developed to control the expression of canine IFN-λ3. The antiviral effects of canine IFN-λ3 were determined in Madin-Darby canine kidney cells and canine tracheal epithelial cells. After transducing each cell line with recombinant adenovirus containing canine interferon lambda3 gene (Ad-caIFNλ3), the mRNA-expression of interferon-stimulated genes Mx1, ISG15, and OAS1 increased significantly (P < 0.05). The replication of canine influenza virus (CIV) was significantly suppressed in Ad-caIFNλ3-infected cells. These results indicate that the newly constructed adenoviral vector system could express canine IFN-λ3, which could subsequently inhibit CIV replication in two canine cell lines. These data imply that the recombinant Ad-caIFNλ3 can potentially be used to treat canine influenza and other viral diseases.

Antibody-Based Targeting of Interferon-Beta-1a Mutein in HER2-Positive Cancer Enhances Antitumor Effects Through Immune Responses and Direct Cell Killing

Type I interferon (IFN) has been approved as an anticancer agent to treat some malignancies. However, IFNs have a short in vivo half-life, systemic toxicity, and poor biophysical properties, which prevent it from being widely used for cancer therapy. This study aimed to construct recombinant IFN-β-1a mutein immunocytokines that comprise a human epidermal growth factor receptor 2 (HER2)-targeting antibody and IFN-β muteins with an additional glycosylation, which can overcome the limitation of the cytokine itself. Hence, the molecular design aims to 1) enhance productivity and biophysical properties by adding secondary glycosylation in IFN-β, 2) increase the therapeutic index of IFN-β therapy by preferential retention at the tumor by possessing high affinity for HER2-expressing cancer cells, and 3) improve the pharmacokinetics and, thus, the convenience of IFN-β administration. The yield of trastuzumab-IFN-β mutein was higher than that of trastuzumab-wild-type IFN-β in the mammalian cell culture system. Trastuzumab-IFN-β mutein showed similar IFN activity and HER2-targeting ability equivalent to that of IFN-β mutein and trastuzumab, respectively. Trastuzumab-IFN-β mutein directly inhibited the growth of HER2-positive gastric cancer cell lines and was more effective than trastuzumab or IFN-β mutein alone. Trastuzumab-IFN-β mutein and IFN-β mutein displayed enhanced immune cell-mediated cytotoxicity. Collectively, trastuzumab-IFN-β mutein may have indirect immune cell-mediated antitumor effects and direct cell growth inhibitory effects. Tumor-targeting effect of trastuzumab-IFN-β mutein was analyzed using in vivo fluorescence imaging. The accumulation of trastuzumab-IFN-β mutein was observed in HER2-positive tumors rather than other tissues except the liver. To evaluate the both direct tumor growth inhibition effect and indirect immune cell-mediated antitumor effect, we tested the effect of trastuzumab-IFN-β mutein in HER2-positive cancer xenograft models using nude mice or humanized mice. Trastuzumab-IFN-β mutein could significantly enhance tumor regression when compared with trastuzumab or IFN-β mutein. In addition, an increase in tumor-infiltrating lymphocytes was observed in the trastuzumab-IFN-β mutein-treated group, implying that the tumor-targeting IFN-β may have an enhanced antitumor effect through increased immune response. Therefore, targeting IFN-β with an anti-HER2 monoclonal antibody makes the immunocytokine more potent than either agent alone. These novel findings suggest that trastuzumab-IFN-β mutein merits clinical evaluation as a new candidate of anticancer therapeutics.

Pro- and Anti-fibrogenic Functions of Gram-Negative Bacterial Lipopolysaccharide in the Liver

Extensive research performed over several decades has identified cells participating in the initiation and progression of fibrosis, and the numerous underlying inter- and intra-cellular signaling pathways. However, liver fibrosis continues to be a major clinical challenge as the precise targets of treatment are still elusive. Activation of physiologically quiescent perisinusoidal hepatic stellate cells (HSCs) to a myofibroblastic proliferating, contractile and fibrogenic phenotype is a critical event in the pathogenesis of chronic liver disease. Thus, elucidation of the mechanisms of the reversal to quiescence or inhibition of activated HSCs, and/or their elimination via apoptosis has been the focus of intense investigation. Lipopolysaccharide (LPS), a gut-resident Gram-negative bacterial endotoxin, is a powerful pro-inflammatory molecule implicated in hepatic injury, inflammation and fibrosis. In both acute and chronic liver injury, portal venous levels of LPS are elevated due to increased intestinal permeability. LPS, via CD14 and Toll-like receptor 4 (TLR4) and its adapter molecules, stimulates macrophages, neutrophils and several other cell types to produce inflammatory mediators as well as factors that can activate HSCs and stimulate their fibrogenic activity. LPS also stimulates synthesis of pro- and anti-inflammatory cytokines/chemokines, growth mediators and molecules of immune regulation by HSCs. However, LPS was found to arrest proliferation of activated HSCs and to convert them into non-fibrogenic phenotype. Interestingly, LPS can elicit responses in HSCs independent of CD14 and TLR4. Identifying and/or developing non-inflammatory but anti-fibrogenic mimetics of LPS could be relevant for treating liver fibrosis.

Converting Lymphoma Cells into Potent Antigen-Presenting Cells for Interferon-Induced Tumor Regression

Anti-hCD20 is a therapeutic mAb that is clinically used to treat B-cell lymphoma. Some lymphomas are resistant to anti-hCD20; others relapse after treatment with anti-hCD20. Using a syngeneic immunocompetent mouse model, we observed that targeting lymphoma with interferon-α (IFNα) abolished resistance of B-cell lymphoma to anti-CD20 while limiting interferon (IFN)-associated systemic toxicity in the host. Control of tumors by a fusion of anti-CD20 and IFNα (anti-CD20-IFNα) depended on existing tumor-infiltrating CD8⁺ T cells. Although lymphomas were resistant to IFN-directed killing, IFN-exposed tumor cells became the dominant antigen-presenting cells (APC) for the reactivation of tumor-infiltrating CD8⁺ T cells that then controlled those lymphomas. Anti-CD20-IFNα also abolished checkpoint blockade resistance in advanced B-cell lymphoma. Our findings indicate that anti-CD20-IFNα eradicates B-cell lymphoma by employing tumor cells as APCs to reactivate tumor-infiltrating CD8⁺ T cells and synergizing with anti-PD-L1 treatment. Cancer Immunol Res; 5(7); 560-70. ©2017 AACR.

Antibody-Based Cancer Therapy: Successful Agents and Novel Approaches

Since their discovery, antibodies have been viewed as ideal candidates or "magic bullets" for use in targeted therapy in the fields of cancer, autoimmunity, and chronic inflammatory disorders. A wave of antibody-dedicated research followed, which resulted in the clinical approval of a first generation of monoclonal antibodies for cancer therapy such as rituximab (1997) and cetuximab (2004), and infliximab (2002) for the treatment of autoimmune diseases. More recently, the development of antibodies that prevent checkpoint-mediated inhibition of T cell responses invigorated the field of cancer immunotherapy. Such antibodies induced unprecedented long-term remissions in patients with advanced stage malignancies, most notably melanoma and lung cancer, that do not respond to conventional therapies. In this review, we will recapitulate the development of antibody-based therapy, and detail recent advances and new functions, particularly in the field of cancer immunotherapy. With the advent of recombinant DNA engineering, a number of rationally designed molecular formats of antibodies and antibody-derived agents have become available, and we will discuss various molecular formats including antibodies with improved effector functions, bispecific antibodies, antibody-drug conjugates, antibody-cytokine fusion proteins, and T cells genetically modified with chimeric antigen receptors. With these exciting advances, new antibody-based treatment options will likely enter clinical practice and pave the way toward more successful control of malignant diseases.

Effect of Antiviral Therapy on Serum Activity of Angiotensin Converting Enzyme in Patients with Chronic Hepatitis C

Introduction:

Renin-angiotenzin system (RAS) is frequently activated in patients with chronic liver disease. Angiotenzin - II (AT-II), produced by angiotenzin converting enzyme (ACE), has many physiological effects, including an important role in liver fibrogenesis. Combined antiviral therapy with PEG-IFN and ribavirin besides its antiviral effect also leads to a reduction in liver parenchyma fibrosis.

Aim of the study:

Determining the value of ACE in serum of patients with chronic hepatitis C before and after combined antiviral therapy, as well as the value of ACE activities in sera of the control group.

Materials and methods:

We studied 50 patients treated at Gastroenterohepatology Department, in the time-period of four years. Value of ACE in serum was determined by Olympus AU 400 device, with application of kit “Infinity TN ACE Liquid Stable Reagent”. HCV RNA levels in sera were measured by real time PCR. HCV RNA test was performed with modular analysis of AMPLICOR and COBAS AMPLICOR HCV MONITOR test v2.0, which has proved infection and was used for quantification of the viruses and monitoring of the patients’ response to therapy. Liver histology was evaluated in accordance with the level of necroinflammation activity and stage of fibrosis.

Results:

Serum activities of ACE in chronic hepatitis C patients is statistically higher than the values in the control group (p=0.02). Antiviral therapy in chronic hepatitis C patients statistically decreases serum activities of ACE (p= 0.02) and indirectly affects fibrogenesis of the liver parenchyma. Correlation between ACE and ALT activity after the therapy was proved (0.3934).

Conclusion:

Our findings suggest that the activity of ACE in serum is a good indirect parameter of the liver damage, and could be used as an indirect prognostic factor of the level of liver parenchyma damage. Serum activity of ACE can be used as a parameter for non-invasive assessment of intensity of liver damage.

Oncolytic adenovirus expressing interferon alpha in a syngeneic Syrian hamster model for the treatment of pancreatic cancer

BACKGROUND

The addition of interferon (IFN) alpha to adjuvant chemoradiotherapy regimens resulted in remarkable improvements in survival for pancreatic cancer patients. However, systemic toxicities and insufficient levels of IFN at the tumor sites have limited its widespread adoption in treatment schemes. We have previously developed an IFN-expressing conditionally replicative oncolytic adenovirus and demonstrated its therapeutic effects both in vitro and in vivo. Here, the same vectors were tested in a syngeneic and immunocompetent Syrian hamster model to better understand the roles of adenoviral replication and of the pleiotropic effects of IFN on pancreatic tumor growth suppression.

METHODS

Oncolytic adenoviruses expressing human or hamster IFN were designed and generated. Viral vectors were tested in vitro to determine qualitative and quantitative cell viability, cyclooxygenase 2 (Cox2) promoter activity, and IFN production. For the in vivo studies, subcutaneous hamster pancreatic cancer tumors were treated with 1 intratumoral dose of virus. Similarly, 1 intraperitoneal dose of virus was used to prolong survival in a carcinomatosis model.

RESULTS

All cell lines tested demonstrated Cox2 promoter activity. The oncolytic potential of a replication competent adenovirus expressing the IFN cytokine was clearly demonstrated. These viruses resulted in significant tumor growth suppression and survival increases compared with controls in a hamster model.

CONCLUSION

The profound therapeutic potential of an IFN-expressing oncolytic adenovirus for the treatment of pancreatic cancer was demonstrated in a syngeneic Syrian hamster model. These results strongly suggest the potential application of our viruses as part of combination regimens with other therapeutics.

Antibody-cytokine fusion proteins for treatment of cancer: engineering cytokines for improved efficacy and safety

The true potential of cytokine therapies in cancer treatment is limited by the inability to deliver optimal concentrations into tumor sites due to dose-limiting systemic toxicities. To maximize the efficacy of cytokine therapy, recombinant antibody-cytokine fusion proteins have been constructed by a number of groups to harness the tumor-targeting ability of monoclonal antibodies. The aim is to guide cytokines specifically to tumor sites where they might stimulate more optimal anti-tumor immune responses while avoiding the systemic toxicities of free cytokine therapy. Antibody-cytokine fusion proteins containing interleukin (IL)-2, IL-12, IL-21, tumor necrosis factor (TNF)α, and interferons (IFNs) α, β, and γ have been constructed and have shown anti-tumor activity in preclinical and early-phase clinical studies. Future priorities for development of this technology include optimization of tumor targeting, bioactivity of the fused cytokine, and choice of appropriate agents for combination therapies. This review is intended to serve as a framework for engineering an ideal antibody-cytokine fusion protein, focusing on previously developed constructs and their clinical trial results.

Targeted delivery of interferon-α to hepatitis B virus-infected cells using T-cell receptor-like antibodies

During antiviral therapy, specific delivery of interferon-α (IFNα) to infected cells may increase its antiviral efficacy, trigger a localized immune reaction, and reduce the side effects caused by systemic administration. Two T-cell receptor-like antibodies (TCR-L) able to selectively bind hepatitis B virus (HBV)-infected hepatocytes of chronic hepatitis B patients and recognize core (HBc18-27) and surface (HBs183-91) HBV epitopes associated with different human leukocyte antigen (HLA)-A*02 alleles (A*02:01, A*02:02, A*02:07, A*02:11) were generated. Each antibody was genetically linked to two IFNα molecules to produce TCR-L/IFNα fusion proteins. We demonstrate that the fusion proteins triggered an IFNα response preferentially on the hepatocytes presenting the correct HBV-peptide HLA-complex and that the mechanism of the targeted IFNα response was dependent on the specific binding of the fusion proteins to the HLA/HBV peptide complexes through the TCR-like variable regions of the antibodies.

CONCLUSION

TCR-L antibodies can be used to target cytokines to HBV-infected hepatocytes in vitro. Fusion of IFNα to TCR-L decreased the intrinsic biological activity of IFNα but preserved the overall specificity of the protein for the cognate HBV peptide/HLA complexes. This induction of an effective IFNα response selectively in HBV-infected cells might have a therapeutic advantage in comparison to the currently used native or pegylated IFNα.

Understanding the mechanism of hepatic fibrosis and potential therapeutic approaches

Hepatic fibrosis (HF) is a progressive condition with serious clinical complications arising from abnormal proliferation and amassing of tough fibrous scar tissue. This defiance of collagen fibers becomes fatal due to ultimate failure of liver functions. Participation of various cell types, interlinked cellular events, and large number of mediator molecules make the fibrotic process enormously complex and dynamic. However, with better appreciation of underlying cellular and molecular mechanisms of fibrosis, the assumption that HF cannot be cured is gradually changing. Recent findings have underlined the therapeutic potential of a number of synthetic compounds as well as plant derivatives for cessation or even the reversal of the processes that transforms the liver into fibrotic tissue. It is expected that future inputs will provide a conceptual framework to develop more specific strategies that would facilitate the assessment of risk factors, shortlist early diagnosis biomarkers, and eventually guide development of effective therapeutic alternatives.

Understanding the mechanism of hepatic fibrosis and potential therapeutic approaches

Hepatic fibrosis (HF) is a progressive condition with serious clinical complications arising from abnormal proliferation and amassing of tough fibrous scar tissue. This defiance of collagen fibers becomes fatal due to ultimate failure of liver functions. Participation of various cell types, interlinked cellular events, and large number of mediator molecules make the fibrotic process enormously complex and dynamic. However, with better appreciation of underlying cellular and molecular mechanisms of fibrosis, the assumption that HF cannot be cured is gradually changing. Recent findings have underlined the therapeutic potential of a number of synthetic compounds as well as plant derivatives for cessation or even the reversal of the processes that transforms the liver into fibrotic tissue. It is expected that future inputs will provide a conceptual framework to develop more specific strategies that would facilitate the assessment of risk factors, shortlist early diagnosis biomarkers, and eventually guide development of effective therapeutic alternatives.

AAV vectors transduce hepatocytes in vivo as efficiently in cirrhotic as in healthy rat livers

In liver cirrhosis, abnormal liver architecture impairs efficient transduction of hepatocytes with large viral vectors such as adenoviruses. Here we evaluated the ability of adeno-associated virus (AAV) vectors, small viral vectors, to transduce normal and cirrhotic rat livers. Using AAV serotype-1 (AAV1) encoding luciferase (AAV1Luc) we analyzed luciferase expression with a CCD camera. AAV1Luc was injected through the hepatic artery (intra-arterial (IA)), the portal vein (intra-portal (IP)), directly into the liver (intra-hepatic (IH)) or infused into the biliary tree (intra-biliar). We found that AAV1Luc allows long-term and constant luciferase expression in rat livers. Interestingly, IP administration leads to higher expression levels in healthy than in cirrhotic livers, whereas the opposite occurs when using IA injection. IH administration leads to similar transgene expression in cirrhotic and healthy rats, whereas intra-biliar infusion is the least effective route. After 70% partial hepatectomy, luciferase expression decreased in the regenerating liver, suggesting lack of efficient integration of AAV1 DNA into the host genome. AAV1Luc transduced mainly the liver but also the testes and spleen. Within the liver, transgene expression was found mainly in hepatocytes. Using a liver-specific promoter, transgene expression was detected in hepatocytes but not in other organs. Our results indicate that AAVs are convenient vectors for the treatment of liver cirrhosis.

Inhibitory effect of human interferon-beta-1a on activated rat and human hepatic stellate cells

BACKGROUND AND AIMS

Hepatic stellate cells (HSC) are the primary cell type mediating hepatic fibrosis. Although known for its antiviral effects, the inhibitory effects of interferon-beta (IFN-β) on HSC treatment have not yet been established.

METHODS

Both human and rat activated HSC cell lines were incubated with increasing concentrations of recombinant human IFN-β1a (rhIFN-β1a) for 24, 48 or 72 h. The effects of rhIFN-β1a on α-smooth muscle actin (α-SMA), collagen types I and III, transforming growth factor-β1 (TGF-β1), platelet-derived growth factor-BB (PDGF-BB), and mothers against decapentaplegic homolog (Smad4, Smad7) expression in HSC were examined using Western blotting and immunocytochemistry. Proliferation of HSC was evaluated via bromodeoxyuridine assay.

RESULTS

rhIFN-β1a treatment had a dose-dependent, inhibitory effect on α-SMA and collagen type I protein expression. In addition, rhIFN-β1a decreased the expression of collagen type III, TGF-β1, PDGF-BB and Smad4 protein expression in HSC compared with untreated cells. We also observed increased Smad7 protein expression and decreased proliferation in rhIFN-β1a-treated HSC.

CONCLUSIONS

Our data suggest that rhIFN-β1a treatment decreased α-SMA and collagen expression and inhibited the activation of HSC through the inhibition of the TGF-β and PDGF pathways.

Administration route-dependent induction of antitumor immunity by interferon-alpha gene transfer

Type I interferon (IFN) protein is a cytokine with pleiotropic biological functions that include induction of apoptosis, inhibition of angiogenesis, and immunomodulation. We have demonstrated that intratumoral injection of an IFN-alpha-expressing adenovirus effectively induces cell death of cancer cells and elicits a systemic tumor-specific immunity in several animal models. On the other hand, reports demonstrated that an elevation of IFN in the serum following an intramuscular delivery of a vector is able to activate antitumor immunity. In this study, we compared the intratumoral and systemic routes of IFN gene transfer with regard to the effect and safety of the treatment. Intratumoral injection of an IFN-alpha adenovirus effectively activated tumor-responsive lymphocytes and caused tumor suppression not only in the gene-transduced tumors but also in distant tumors, which was more effective than the intravenous administration of the same vector. The expression of co-stimulatory molecules on CD11c(+) cells isolated from regional lymph nodes was enhanced by IFN gene transfer into the tumors. Systemic toxicity such as an elevation of hepatic enzymes was much lower in mice treated by intratumoral gene transfer than in those treated by systemic gene transfer. Our data suggest that the intratumoral route of the IFN vector is superior to intravenous administration, due to the effective induction of antitumor immunity and the lower toxicity.

Targeted delivery of interferon-alpha via fusion to anti-CD20 results in potent antitumor activity against B-cell lymphoma

The anti-CD20 antibody rituximab has substantially improved outcomes in patients with B-cell non-Hodgkin lymphomas. However, many patients are not cured by rituximab-based therapies, and overcoming de novo or acquired rituximab resistance remains an important challenge to successful treatment of B-cell malignancies. Interferon-alpha (IFNalpha) has potent immunostimulatory properties and antiproliferative effects against some B-cell cancers, but its clinical utility is limited by systemic toxicity. To improve the efficacy of CD20-targeted therapy, we constructed fusion proteins consisting of anti-CD20 and murine or human IFNalpha. Fusion proteins had reduced IFNalpha activity in vitro compared with native IFNalpha, but CD20 targeting permitted efficient antiproliferative and proapoptotic effects against an aggressive rituximab-insensitive human CD20(+) murine lymphoma (38C13-huCD20) and a human B-cell lymphoma (Daudi). In vivo efficacy was demonstrated against established 38C13-huCD20 grown in syngeneic immunocompetent mice and large, established Daudi xenografts grown in nude mice. Optimal tumor eradication required CD20 targeting, with 87% of mice cured of rituximab-insensitive tumors. Gene knockdown studies revealed that tumor eradication required expression of type I IFN receptors on the tumor cell surface. Targeting type I IFNs to sites of B-cell lymphoma by fusion to anti-CD20 antibodies represents a potentially useful strategy for treatment of B-cell malignancies.

Intratumoral interferon-alpha gene transfer enhances tumor immunity after allogeneic hematopoietic stem cell transplantation

One of the major challenges in the treatment of solid cancers by allogenic hematopoietic stem cell transfer (alloHSCT) is the specific enhancement of antitumor immunity. Interferon (IFN) is a cytokine with pleiotropic biological functions including an immunomoduration, and our preclinical studies have shown that an intratumoral IFN-alpha gene transfer induced strong local tumor control and systemic tumor-specific immunity. In the present study, we examined whether the IFN-alpha gene transfer could enhance recognition of tumor-associated antigens by donor T cells and augment the antitumor activity of alloHSCT. First, when a mouse IFN-alpha adenovirus vector (Ad-mIFN) was injected into subcutaneous xenografts of syngeneic renal and colon cancer cells, tumor growth was significantly suppressed in a dose-dependent manner. A significant tumor cell death and infiltration of immune cells was recognized in the Ad-mIFN-injected tumors, and the dendritic cells isolated from the tumors showed a strong Th1-oriented response. The antitumor effect of Ad-mIFN was then examined in a murine model of minor histocompatibility antigen-mismatched alloHSCT. The intratumoral IFN-alpha gene transfer caused significant tumor suppression in the alloHSCT recipients, and this suppression was evident not only in the gene-transduced tumors but also in simultaneously inoculated distant tumors which did not receive the vector injection. A cytotoxicity assay showed specific tumor cell lysis by donor T cells responding to IFN-alpha. Graft-versus-host disease was not exacerbated serologically or clinically in the mice treated with IFN-alpha. This combination strategy deserves evaluation in future clinical trials for human solid cancers.

Extracellular matrix interacts with interferon alpha protein: retention and display of cytotoxicity

We have been investigating the efficacy of an intratumoral interferon (IFN)-alpha gene transfer against solid cancers, and found that when the gene is transduced into the subcutaneous tumors, IFN-alpha concentration is markedly increased in the injected tumor but not in the serum. To explain this effective confinement of IFN-alpha to target tissues, we hypothesized that the extracellular matrix in the tumors interacts with IFN-alpha. In this study, a solid-phase-binding assay and immunoprecipitation demonstrated that the IFN-alpha binds directly to matrix proteins. Immunohistochemical staining showed a co-localization of IFN-alpha with pericellular fibronectin. In addition, matrix-bound IFN-alpha protein transduced intracellular signaling and potentiated its cytotoxic activity, suggesting that the retention of IFN-alpha protein on extracellular matrix is likely to play a role in its in vivo biological activity. The data suggest a therapeutic advantage of the intratumoral IFN-alpha gene transfer over the conventional parenteral therapy both in the safety and efficacy.

Dual therapeutic effects of interferon-alpha gene therapy in a rat hepatocellular carcinoma model with liver cirrhosis

Human hepatocellular carcinoma (HCC) often arises from a background of liver cirrhosis. Therefore, in order to develop therapeutic strategies for HCC, an animal model bearing multifocal liver tumors accompanied by liver cirrhosis is a preferred experimental setting. In this study, we developed a rapid and reproducible method for generating such a model in rats by weekly administration of diethylnitrosamine (DEN) at doses based on body weight (BW). By adjusting the duration of administration of DEN, the animals could be induced to develop HCC alone, or HCC and liver cirrhosis simultaneously. The latter model was used for evaluating the therapeutic effects of adenoviral delivery of interferon-alpha (IFN-alpha). Our results demonstrated that targeting of IFN-alpha expression to the liver significantly reduced liver tumor volume and ameliorated liver cirrhosis. Mechanistic studies revealed that IFN-alpha gene therapy induced immunomodulatory, antiproliferative, and proapoptotic activities that were effective in the control of tumor growth, and reduced the expressions of transforming growth factor-beta (TGF-beta) and tissue inhibitor of metalloproteinase-1 (TIMP-1), leading to amelioration of liver cirrhosis. These results suggest that IFN-alpha gene therapy is a promising strategy to treat HCC patients who have concomitant liver cirrhosis.

Baculovirus-mediated interferon alleviates dimethylnitrosamine-induced liver cirrhosis symptoms in a murine model

The wild-type baculovirus Autographa californica multiple nuclear polyhedrosis virus (AcMNPV) infects a range of mammalian cell types in vitro but does not replicate in these cells. The current study investigated the in vivo effect of AcMNPV in the mouse model of liver cirrhosis induced by the mutagen dimethylnitrosamine. Intraperitoneal injection of AcMNPV induced an immune response. The baculovirus was taken up by the liver and spleen where it suppressed liver injury and fibrosis through the induction of interferons. This study presents the first evidence of the feasibility of using baculovirus to treat liver cirrhosis.

Gene therapy for hepatic fibrosis

Hepatic fibrosis is a common pathological process of chronic liver diseases, characterized by increased synthesis and relatively low degradation of extracellular matrix (ECM) resulting from their dynamic imbalance. Recent progress in molecular biology techniques has made it possible to treat hepatic fibrosis with gene therapy. At present, the commonly used method is to induce the expression of exogenous genes by transducing enough therapeutic genes into injured liver to delay or cure liver fibrosis.

PDGF-receptor beta-targeted adenovirus redirects gene transfer from hepatocytes to activated stellate cells

Chronic liver damage may lead to liver fibrosis. In this process, hepatic activated stellate cells are the key players. Thus, activated stellate cells are attractive targets for antifibrotic gene therapy. Recombinant adenovirus is a promising vehicle for delivering therapeutic genes to liver cells. However, this vector has considerable tropism for hepatocytes and Kupffer cells. The aim of this study is therefore to retarget the adenovirus to the activated stellate cells while reducing its affinity for hepatocytes. We constructed a fusion protein with affinity for both the adenovirus and the platelet derived growth factor-receptor beta (PDGF-Rbeta). In contrast to other cells, the PDFG-Rbeta is highly expressed on activated stellate cells. The targeting moiety, the PDGF peptide CSRNLIDC, was cloned in front of the single-chain antibody fragment (S11) directed against the adenoviral knob. This fusion protein enhanced adenoviral gene transfer in both 3T3 fibroblasts and primary isolated activated rat stellate cells by 10-60-fold. A fusion protein with a scrambled PDGF peptide (CIDNLSRC) did not accomplish this effect. Importantly, the PDGF-Rbeta-retargeted adenovirus showed a 25-fold reduced tropism for primary rat hepatocytes. Our novel approach demonstrates that therapeutic genes can be selectively directed to stellate cells. This opens new possibilities for the treatment of liver fibrosis.

Blockade of renin-angiotensin system in antifibrotic therapy

Recent studies have shown that the renin-angiotensin system (RAS) plays a pivotal role in liver fibrosis. An intrahepatic RAS is expressed in chronically damaged livers, and angiotensin-II (AT-II) reportedly stimulates contraction and proliferation of the activated hepatic stellate cells (Ac-HSC), and increases the transforming growth factor-beta (TGF-beta) expression through angiotensin type-I receptors (AT1-R). Some studies have demonstrated that the clinically used angiotensin-converting enzyme (ACE) inhibitor (ACE-I), and AT1-R blockers (ARB) significantly attenuated experimental liver fibrosis along with suppression of the Ac-HSC and hepatic TGF-beta expression. Angiotensin-II also stimulates the tissue inhibitor of metalloproteinases-1 (TIMP-1) in a dose- and time-dependent manner via protein kinase-C as an intracellular signaling cascade in the Ac-HSC, and these effects are completely suppressed by ARB. Combination treatment with low-dose interferon (IFN) and ACE-I exerts a stronger inhibitory effect than either single agent on its own. In humans it has been reported that ARB markedly improved the liver fibrosis score and TGF-beta expression in patients with chronic hepatitis C and non-alcoholic steatohepatitis. Serum fibrosis markers also significantly improved by treatment with low-dose IFN and ACE-I in patients with chronic hepatitis C, refractory to IFN monotherapy. Collectively, these data suggest that the interaction between AT-II and AT1-R plays a pivotal role in liver fibrosis development. Because both ACE-I and ARB are widely used in clinical practice without serious side-effects, these drugs in combination with IFN may provide a new strategy for antifibrosis therapy.

Delivery of viral vectors to hepatic stellate cells in fibrotic livers using HVJ envelopes fused with targeted liposomes

Hepatic stellate cells (HSC) are a major target for antifibrotic therapies in the liver and in particular gene delivery to these cells would be relevant. Previously, we demonstrated that mannose 6-phosphate human serum albumin (M6P-HSA) coupled liposomes accumulate in HSC in fibrotic livers. Here we prepared a M6P-HSA modified viral vector that allows the targeted delivery of plasmid DNA to HSC. Therefore, UV inactivated hemagglutinating virus of Japan (HVJ) containing plasmid DNA was fused with M6P-HSA liposomes to yield HVJ liposomes targeted to HSC. These new particles had a diameter of approximately 200 nm, as determined by electron microscopy. In a carbon tetrachloride mouse model of liver fibrosis, M6P-HSA-HVJ-liposomes associated with HSC. In conclusion, our results demonstrate that fusion of M6P-HSA liposomes with HVJ envelopes results in HVJ particles that accumulate in HSC, allowing for new possibilities to interfere with fibrosis in the liver.

Local interferon-alpha gene therapy elicits systemic immunity in a syngeneic pancreatic cancer model in hamster

The interferon (IFN) protein is a cytokine with pleiotropic biological functions that include induction of apoptosis, inhibition of angiogenesis and immunomodulation. We previously examined the two antitumor mechanisms, taking advantage of the fact that IFN-alpha did not show cross-species activity in its in vivo effect. In a nude mouse subcutaneous xenograft model using human pancreatic cancer cells, the expression of human IFN-alpha effectively induced cell death of human pancreatic cancer cells, whereas mouse IFN-alpha augmented antitumor immunity by stimulation of natural killer cells. Here, we extended our investigation to a syngeneic pancreatic cancer model, so that the integrated antitumor activity of local IFN-alpha gene therapy, including the antiproliferative, proapoptotic, antiangiogeneic and immunomodulatory effects, can be evaluated rigorously. When a recombinant hamster IFN-alpha adenovirus was injected into syngeneic subcutaneous tumors of hamster pancreatic cancer (PGHAM-1) cells in Syrian hamster, tumor growth was significantly suppressed due to cell death and T cell- and natural killer cell-mediated antitumor immunity. Moreover, in this case, tumor regression was observed not only for the injected subcutaneous tumors but also for the untreated tumors both in the peritoneal cavity and at distant sites. No significant systemic toxicity was observed in the treated hamsters. Moreover, the subcutaneous rechallenge of PGHAM-1 cells was rejected in three of four cured hamsters from the initial tumor challenge. This study further demonstrated that local IFN-alpha gene therapy is a promising therapeutic strategy for pancreatic cancer, due to its multiple mechanisms of antitumor activity and its lack of significant toxicity.

Adenovirus-mediated interferon alpha gene transfer induces regional direct cytotoxicity and possible systemic immunity against pancreatic cancer

We previously demonstrated a characteristically high sensitivity of pancreatic cancer cells to interferon alpha (IFN-alpha) gene transfer, which induced a more prominent growth suppression and cell death in pancreatic cancer cells than in other types of cancers and normal cells. The IFN-alpha protein can exhibit both direct cytotoxicity and indirect immunological antitumour activity. Here, we dissected and examined the two mechanisms, taking advantage of the fact that IFN-alpha did not show any cross-species activity in its in vivo effect. When a human IFN-alpha adenovirus was injected into subcutaneous xenografts of human pancreatic cancer cells in nude mice, tumour growth was significantly suppressed due to cell death in an adenoviral dose-dependent manner. The IFN-alpha protein concentration was markedly increased in the injected subcutaneous tumour, but leakage of the potent cytokine into the systemic blood circulation was minimal. When a mouse IFN-alpha adenovirus was injected into the same subcutaneous tumour system, all mice showed significant tumour inhibition, an effect that was dependent on the indirect antitumour activities of IFN-alpha, notably a stimulation of natural killer cells. Moreover, in this case, tumour regression was observed not only for the injected subcutaneous tumours but also for the untreated tumours at distant sites. This study suggested that a local IFN-alpha gene therapy is a promising therapeutic strategy for pancreatic cancer, due to its dual mechanisms of antitumour activities and lack of significant toxicity.

Mechanisms of liver fibrosis

Liver fibrosis represents a significant health problem worldwide of which no acceptable therapy exists. The most characteristic feature of liver fibrosis is excess deposition of type I collagen. A great deal of research has been performed to understand the molecular mechanisms responsible for the development of liver fibrosis. The activated hepatic stellate cell (HSC) is the primary cell type responsible for the excess production of collagen. Following a fibrogenic stimulus, HSCs change from a quiescent to an activated, collagen-producing cell. Numerous changes in gene expression are associated with HSC activation including the induction of several intracellular signaling cascades, which help maintain the activated phenotype and control the fibrogenic and proliferative state of the cell. Detailed analyses in understanding the molecular basis of collagen gene regulation have revealed a complex process offering the opportunity for multiple potential therapeutic strategies. However, further research is still needed to gain a better understanding of HSC activation and how this cell maintains its fibrogenic nature. In this review we describe many of the molecular events that occur following HSC activation and collagen gene regulation that contribute to the fibrogenic nature of these cells and provide a review of therapeutic strategies to treat this disease.

Adeno-associated virus mediated interferon-gamma inhibits the progression of hepatic fibrosis in vitro and in vivo

AIM: To investigate the effects of adeno-associated virus (AAV) mediated expression of human interferon-γ for gene therapy in experimental hepatic fibrosis in vitro and in vivo.

METHODS: We constructed the recombinant AAV encoding human INF-γ (rAAV- INF-γ) and took the primary rat hepatic stellate cells and carbon tetrachloride induced rats as the experimental hepatic fibrosis model in vitro and in vivo. Immunocytochemistry analysis was used to reveal the expression of α-SMA, the marker protein expressed in hepatic stellate cells. The mRNA expression of TGF-β, TIMP-1, and MMP-13 were analyzed by RT-PCR method. In vivo study, the hydroxyproline content in liver and serum AST, ALT were also detected.

RESULTS: in vitro study, AAV vector could mediated efficient expression of human INF-γ, which inhibit the activation of hepatic stellate cells, decrease the expression of α-SMA and mRNA of TIMP-1, TGF-β, with the MMP-13 unchanged. In vivo study, the histological examination revealed that rAAV- INF-γ could inhibit the progression of the hepatic fibrosis. In the rAAV-INF-γ induced group, the hydroxyproline content and serum AST, ALT level were decreased to 177 ± 28 µg/g wet liver, 668.5 ± 140.0, 458.4 ± 123.5 U/L, compare with the fibrosis control group 236 ± 31 µg/g wet liver, 1 019.1 ± 276.3, 770.5 ± 154.3 U/L, respectively (P < 0.01). mRNA expression of TIMP-1 in the rAAV-INF-γ induced rat liver was decreased while no significant change was observed in TGF-β and MMP-13.

CONCLUSION: All these results indicated that rAAV-INF-γ has potential effects for gene therapy of hepatic fibrosis, which could inhibit the progression of hepatic fibrosis.

Intraperitoneal injection of adenovirus expressing antisense K-ras RNA suppresses peritoneal dissemination of hamster syngeneic pancreatic cancer without systemic toxicity

We examined the antitumor effect and safety of the adenovirus-mediated expression of antisense K-ras RNA in two peritoneal dissemination models of pancreatic cancer. First, we found that the infection of an adenovirus vector expressing antisense human K-ras RNA (AxCA-AS) induced significant apoptosis in vitro in human pancreatic cancer cells with K-ras mutation. Second, the intraperitoneal (ip) injection of AxCA-AS effectively suppressed the growth of human pancreatic cancer cells in the peritoneal cavity of nude mice. Third, in the hamster syngeneic peritoneal dissemination model, the ip injection of an adenovirus expressing antisense hamster K-ras RNA significantly suppressed the peritoneal growth of hamster pancreatic cancer cells, and no significant systemic toxicity was observed in the treated hamsters. This study suggests a feasibility of the development of a therapeutic strategy against pancreatic cancer based on the adenovirus-mediated transduction of an antisense K-ras construct.

Combination of interferon-beta and angiotensin-converting enzyme inhibitor, perindopril, attenuates the murine liver fibrosis development

Recent studies have revealed that both interferon (IFN) and angiotensin-converting enzyme inhibitor (ACE-I) exert an anti-fibrotic effect. The aim of this study was to examine the combined effect of the ACE-I and IFN on the murine hepatic fibrosis development. A model of CCl(4)-induced hepatic fibrosis was used to assess the effect of the clinically used ACE-I, perindopril (PE), and IFN-beta. The PE and IFN were administered after 2-week treatment with CCl(4), and the hepatic indices of fibrosis were assessed at 8 weeks. Single treatment with either PE or IFN at the clinically available comparable doses significantly attenuated liver fibrogenesis associated with suppression of the hepatic hydroxyproline and serum fibrosis markers. The number of alpha-smooth muscle actin-positive cells, and the hepatic alpha1(I)-procollagen mRNA were also markedly inhibited. The inhibitory effect of PE was more potent than IFN, and the combination treatment with PE and IFN almost completely attenuated liver fibrosis development. In vitro, the angiotensin-II (AT-II) type 1 receptor blocker and IFN suppressed the AT-II-induced proliferation and alpha1(I)-procollagen mRNA expression of the activated hepatic stellate cells. The combination treatment of the clinically used PE and IFN may provide a new strategy for anti-liver fibrosis therapy.

Development of gene therapy to target pancreatic cancer

Pancreatic cancer remains one of the most difficult cancers to treat. Its high propensity to infiltrate and metastasize early from a small primary focus necessitates development of a new therapy which can track down the disseminated cancer cells in vivo. Gene therapy may offer new opportunities for a variety of targeting strategies, and we review here some of our work related to the development of targeted gene therapy: 1) Targeting by specific molecular abnormality: Many pancreatic cancer cells show "addiction" to K-ras mutation, while normal cells appear resistant to suppression of K-ras-mediated signaling by antisense K-ras RNA expression adenoviral vector. 2) Targeting by in vivo tumor characteristics: In a peritoneal dissemination model, intraperitoneal lipofection/polyfection can deliver and express transgenes highly preferentially in tumor nodules. 3) Targeting by vector: An efficient protocol for construction of an adenovirus expression vector library has been developed, which will enable a direct functional selection of fiber knob-modified targeting vector species for given cells. 4) Targeting by tumor immunity: Several cytokines not only induce direct cytotoxicity, but are also expected to activate specific immunity to achieve targeted suppression of cancer cells in vivo. Unlike parenteral administration of short-lived recombinant interferon protein, local interferon gene transfer can provide a target tissue-restricted distribution and sustained expression, which may improve the efficacy/safety balance of cytokine therapy. Cancer gene therapy development is, in general, at the stage of proof of principles and safety. However, it is an art of integrated science. The recent rapid progress of related sciences and technologies will expand the potential and consolidate the clinical reality of gene therapy.

Interferon-α and antisense K-ras RNA combination gene therapy against pancreatic cancer

Interferon alpha (IFN-alpha) is used worldwide for the treatment of a variety of cancers. For pancreatic cancer, recent clinical trials using IFN-alpha in combination with standard chemotherapeutic drugs showed some antitumor activity of the cytokine, but the effect was not significant enough to enlist pancreatic cancer as a clinically effective target of IFN-alpha. In general, an improved therapeutic effect and safety are expected for cytokine therapy when given in a gene therapy context, because the technology would allow increased local concentrations of this cytokine in the target sites. In this study, we first examined the antiproliferative effect of IFN-alpha gene transduction into pancreatic cancer cells. The expression of IFN-alpha effectively induced growth suppression and cell death in pancreatic cancer cells, an effect which appeared to be more prominent when compared with other types of cancers and normal cells. Another strategy we have been developing for pancreatic cancer targets its characteristic genetic aberration, K-ras point mutation, and we reported that the expression of antisense K-ras RNA significantly suppressed the growth of pancreatic cancer cells. When these two gene therapy strategies are combined, the expression of antisense K-ras RNA significantly enhanced IFN-alpha-induced cell death (1.3- to 3.5-fold), and suppressed subcutaneous growth of pancreatic cancer cells in mice. Because the 2',5'-oligoadenylate synthetase/RNase L pathway, which is regulated by IFN and induces apoptosis of cells, is activated by double-strand RNA, it is plausible that the double-strand RNA formed by antisense and endogenous K-ras RNA enhanced the antitumor activity of IFN-alpha. This study suggested that the combination of IFN-alpha and antisense K-ras RNA is a promising gene therapy strategy against pancreatic cancer.

Smad4 antisense gene transfer into ito cells and suppressed extracellular matrix production

AIM

To investigate possible role of antisense Smad4 RNA in the regulation of Smad4 and ECM production in Ito cells after blockade of TGF-β1 signal transmission by antisense Smad4.

METHODS

A rat Smad4 cDNA (2.5 kb) was inserted in reverse orientation into the adenoviral shuttle vector pAdv5SR (+), and so pAdvATSmad4 was obtained. PAdvATSmad4 was transfected, together with pJM17, into 293 cells by a liposome-mediated technique. We acquired the recombinant virus (AdvATSmad4) containing the anti-Smad4 gene by PCR detecting method. AdvATSmad4 was amplified and purified and then introduced into the rat Ito cell line CFSC.

RESULTS

The presence of antisense Smad4 RNA was detected by RT-PCR. The expression of Smad4 and the production of extracellular matrix were markedly decreased in the antisense Smad4 transfected cultured cells by in situ hybridization and immunohistochemistry.

CONCLUSION

Antisense RNA of Smad4 can be used successfully to inhibit Ito cell activation, endogenous Smad4 mRNA and extracellular matrix production, and may provide a basis for the development of anti-fibrosis gene therapy.

Adenovirus-mediated gene transfer of interferon alpha inhibits hepatitis C virus replication in hepatocytes

Recently we reported that on-site interferon (IFN)-alpha production in the liver using an adenovirus vector can achieve a substantial confinement of IFN-alpha in the target organ and can improve liver fibrosis in a rat liver cirrhosis model. However, the major therapeutic effect of IFN for hepatitis C virus (HCV)-associated liver diseases is its antiviral effect on HCV. As a prelude to the in vivo HCV infection experiment using a primate animal model, here we examined the antiviral effect of IFN-alpha gene transfer into HCV-positive hepatocytes in vitro. The non-neoplastic human hepatocyte cell line PH5CH8 was inoculated with HCV-positive serum. Successful in vitro HCV replication and thus the validity of this model was confirmed by a strong selection for HCV variants determined by sequence analysis of the hypervariable region and an increase of HCV RNA estimated by real time TaqMan RT-PCR. One day after the inoculation of HCV, PH5CH8 cells were infected with adenoviral vectors encoding human IFN-alpha cDNA. HCV completely disappeared 9 days after the adenoviral infection, which is linked to the increase of 2('),5(')-oligoadenylate synthetase activity, suggesting that IFN-alpha produced by gene transfer effectively inhibits HCV replication in hepatocytes. This study supports the development of IFN-alpha gene therapy for HCV-associated liver diseases.