Involvement of PI3K in HCV-related lymphoproliferative disorders

Hepatitis C virus-associated non-Hodgkin lymphomas: the endless history

Hepatitis C virus (HCV) is a global population problem due to its high prevalence worldwide. In the prognosis of patients with HCV not only hepatic but increasingly frequent of extrahepatic HCV manifestations, such as mixed cryoglobulinemia (MC) and non-Hodgkin's lymphoma (NHL), are important. The role of the HCV virus in the pathogenesis of lymphoproliferative diseases is confirmed by a large number of epidemiological studies, as well as by the effectiveness of antiviral therapy in patients with non-Hodgkin's lymphoma (NHL). The purpose of the review was to provide an overview of epidemiological and biological data explaining the role of HCV in the development of NHL. The review also discusses HCV-associated NHL treatment by the traditional antiviral therapy (interferon and ribavirin) and by the new direct antiviral agents.

MicroRNA Involvement in Signaling Pathways During Viral Infection

The study of miRNAs started in 1993, when Lee et al. observed their involvement in the downregulation of a crucial protein known as LIN-14 in the nematode Caenorhabditis elegans. Since then, great progress has been made regarding research on microRNAs, which are now known to be involved in the regulation of various physiological and pathological processes in both animals and humans. One such example is represented by their interaction with various signaling pathways during viral infections. It has been observed that these pathogens can induce the up-/downregulation of various host miRNAs in order to elude the host’s immune system. In contrast, some miRNAs studied could have an antiviral effect, enabling the defense mechanisms to fight the infection or, at the very least, they could induce the pathogen to enter a latent state. At the same time, some viruses encode their own miRNAs, which could further modulate the host’s signaling pathways, thus favoring the survival and replication of the virus. The goal of this extensive literature review was to present how miRNAs are involved in the regulation of various signaling pathways in some of the most important and well-studied human viral infections. Further on, knowing which miRNAs are involved in various viral infections and what role they play could aid in the development of antiviral therapeutic agents for certain diseases that do not have a definitive cure in the present. The clinical applications of miRNAs are extremely important, as miRNAs targeted inhibition may have substantial therapeutic impact. Inhibition of miRNAs can be achieved through many different methods, but chemically modified antisense oligonucleotides have shown the most prominent effects. Though scientists are far from completely understanding all the molecular mechanisms behind the complex cross-talks between miRNA pathways and viral infections, the general knowledge is increasing on the different roles played by miRNAs during viral infections.

Hepatitis C virus infection and non-hepatocellular malignancies in the DAA era: A systematic review and meta-analysis

BACKGROUND AND AIMS

Direct antiviral agents have greatly improved therapeutic options for chronic hepatitis C. Indeed, former "difficult-to-treat" patients can now be treated and can achieve sustained response. Hepatitis C virus (HCV) is associated with hepatocellular carcinoma and with B-cell non-Hodgkin lymphoma (B-NHL). Other malignancies have been reported to be associated with HCV infection albeit with various grades of evidence. Antineoplastic treatment is often reduced or suspended in HCV-positive cancer patients to avoid "HCV reactivation." In this setting, antiviral therapy combined with antineoplastic protocols may improve the outcome. For this reason, we conducted a systematic review and a meta-analysis to update the association between HCV infection and non-hepatocellular malignancies, and to shed light on the effects exerted by antiviral treatment on the natural history of oncological diseases.

METHODS

Relevant studies were identified by searching PUBMED, EMBASE and MEDLINE up to 1 August 2018. Pooled risk estimates were calculated with random-effects models according to PRISMA guidelines.

RESULTS

A total of 58 studies were included in the analysis: 27 studies of the association between HCV and B-NHL(OR 3.36; 95% CI 2.40-4.72;P < 0.00001);13 studies of the association between sustained virological response and progression-free survival (PFS) in B-NHL patients(OR 9.34; 95% CI 4.90-17.79; P < 0.00001); 13 studies of the association between HCV and intrahepatic-cholangio-carcinoma (OR 3.95;95% CI 2.25-6.94; P < 0.00001); and 5 studies of the association between HCV infection and pancreatic adeno-carcinoma(OR 1.60; 95% CI:1.25-2.04; P = 0.0002).

CONCLUSIONS

This study updates the strong association between B-NHL and HCV infection, confirms the association between HCV and non-hepatocellular tumours, and demonstrates a very strong association between viral eradication and a better outcome of HCV-positive B-NHL.

Heterogeneity and coexistence of oncogenic mechanisms involved in HCV-associated B-cell lymphomas

The association of HCV-infection with B-lymphomas is supported by the regression of most indolent/low-grade lymphomas following anti-viral therapy. Studies on direct and indirect oncogenic mechanisms have elucidated the pathogenesis of HCV-associated B-lymphoma subtypes. These include B-lymphocyte proliferation and sustained clonal expansion by HCV-envelope protein stimulation of B-cell receptors, and prolonged HCV-infected B-cell growth by overexpression of an anti-apoptotic BCL-2 oncogene caused by the increased frequency of t(14;18) chromosomal translocations in follicular lymphomas. HCV has been implicated in lymphomagenesis by a "hit-and-run" mechanism, inducing enhanced mutation rate in immunoglobulins and anti-oncogenes favoring immune escape, due to permanent genetic damage by double-strand DNA-breaks. More direct oncogenic mechanisms have been identified in cytokines and chemokines in relation to NS3 and Core expression, particularly in diffuse large B-cell lymphoma. By reviewing genetic alterations and disrupted signaling pathways, we intend to highlight how mutually non-contrasting mechanisms cooperate with environmental factors toward progression of HCV-lymphoma.

Efficacy and safety of new direct antiviral agents in hepatitis C virus-infected patients with diffuse large B-cell non-Hodgkin's lymphoma

The association of hepatitis C virus (HCV) with non-Hodgkin's lymphoma (NHL) has been demonstrated throughout the world. The new interferon-free direct antiviral agents (DAAs) showed high efficacy and safety, and preliminary data seem to confirm their activity on low-grade NHL. The question arises as whether or not-and how-to treat the HCV-positive patients suffering from diffuse large B-cell lymphomas (DLBCLs). The aim of this observational study was to evaluate whether DAA antiviral treatment of DLBCL/HCV-infected patients in concomitance with chemotherapy is a safe and effective option. Twenty (13 males and 7 females) HCV genotype 1b-positive subjects, undergoing chemotherapy for DLBCL, were enrolled between June 2015 and December 2015. After informed consent, all patients underwent antiviral therapy (AVT) with sofosbuvir/ledipasvir and chemotherapy (14 rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone and 6 cyclophosphamide, doxorubicin, vincristine, and prednisone) for DLBCL. Complete hematological (Revised European-American Lymphoma classification, Ann Arbor, and International Prognostic Index [IPI] scores) and hepatological (viral markers, liver stiffness, and biochemical parameters) evaluations were made. A historical retrospective cohort of 101 DLBCL/HCV-positive patients not undergoing AVT was enrolled for comparison. DAA-treated and untreated patients were similar for sex distribution, IPI score, and NHL stage, and differed for age (older in treated), chemotherapy and use of AVT. Overall survival (OS) and disease-free survival (DFS) were evaluated among a 52-week of follow-up. No statistical difference was found in OS after 52 weeks (P = 0.122), whereas a statistically significant higher DFS was achieved in treated patients (P = 0.036). At the multivariate analysis, only IPI score and AVT were independently correlated with a better DFS. No differences in adverse events were reported.

CONCLUSION

DAA treatment in concomitance with chemotherapy was shown to be safe and effective in influencing remission of aggressive lymphomas in HCV patients. (Hepatology 2018;67:48-55).

Antiviral therapy improves overall survival in hepatitis C virus-infected patients who develop diffuse large B-cell lymphoma

Chronic Hepatitis C virus (HCV) infection is associated with increased incidence of non-Hodgkin lymphoma. Several studies have demonstrated regression of indolent lymphoma with antiviral therapy (AVT) alone. However, the role of AVT in HCV-infected patients with diffuse large B-cell lymphoma (DLBCL) is unclear. We therefore analyzed AVT's impact on oncologic outcomes of HCV-infected patients (cases) who developed DLBCL. Cases seen at our institution (June 2004-May 2014) were matched with uninfected counterparts (controls) and then divided according to prior AVT consisting of interferon-based regimens. We studied 304 patients (76 cases and 228 controls). More cases than controls had extranodal (79% vs. 72%; p = 0.07) and upper gastrointestinal (GI; 42% vs. 24%; p = 0.004) involvement. Cases never given AVT had DLBCL more refractory to first-line chemotherapy than that in the controls (33% vs. 17%; p = 0.05) and exhibited a trend toward more progressive lymphoma at last examination compared to controls (50% vs. 32%; p = 0.09) or cases given AVT (50% vs. 27%; p = 0.06). Cases never given AVT had worse 5-year overall survival (OS) rates than did the controls (HR, 2.3 [95% CI, 1.01-5.3]; p = 0.04). Furthermore, AVT improved 5-year OS rates among cases in both univariate (median [Interquartile range]: 39 [26-56] vs. 16 [6-41] months, p = 0.02) and multivariate analyses (HR = 0.21 [95% CI, 0.06-0.69]; p = 0.01). This study highlights the negative impact of chronic HCV on survival of DLBCL patients and shows that treatment of HCV infection is associated with a better cancer response to chemotherapy and improves 5-year OS.

Virus-driven autoimmunity and lymphoproliferation: the example of HCV infection

HCV chronic infection is characterized by possible development of both hepatic and extrahepatic manifestations. The infection by this both hepatotropic and lymphotropic virus is responsible for polyoligoclonal B-lymphocyte expansion, leading to several immune-mediated disorders. Mixed cryoglobulinemia syndrome that in some cases may evolve to frank B-cell non-Hodgkin's lymphoma is the prototype of HCV-driven autoimmune and lymphoproliferative disorders. The HCV oncogenic potential has been suggested by several clinicoepidemiological and laboratory studies; it includes hepatocellular carcinoma, B-cell non-Hodgkin's lymphoma and papillary thyroid cancer. The definition HCV syndrome refers to the complex of HCV-driven diseases; these latter are characterized by heterogeneous geographical distribution, suggesting a role of other important genetic and/or environmental cofactors. The natural history of HCV syndrome is the result of a multifactorial and multistep pathogenetic process, which may evolve from mild manifestations to systemic autoimmune disorders, and less frequently to malignant neoplasias. The present updated review analyzes the clinical and pathogenetic aspects of the main HCV-associated diseases.

Lipoxin A₄ modulates adaptive immunity by decreasing memory B-cell responses via an ALX/FPR2-dependent mechanism

Specialized proresolving mediators are endogenous bioactive lipid molecules that play a fundamental role in the regulation of inflammation and its resolution. Lipoxins and other specialized proresolving mediators have been identified in important immunological tissues including bone marrow, spleen, and blood. Lipoxins regulate functions of the innate immune system including the promotion of monocyte recruitment and increase macrophage phagocytosis of apoptotic neutrophils. A major knowledge gap is whether lipoxins influence adaptive immune cells. Here, we analyzed the actions of lipoxin A₄ (LXA₄) and its receptor ALX/FPR2 on human and mouse B cells. LXA₄ decreased IgM and IgG production on activated human B cells through ALX/FPR2-dependent signaling, which downregulated NF-κB p65 nuclear translocation. LXA₄ also inhibited human memory B-cell antibody production and proliferation, but not naïve B-cell function. Lastly, LXA₄ decreased antigen-specific antibody production in an OVA immunization mouse model. To our knowledge, this is the first description of the actions of lipoxins on human B cells, demonstrating a link between resolution signals and adaptive immunity. Regulating antibody production is crucial to prevent unwanted inflammation. Harnessing the ability of lipoxins to decrease memory B-cell antibody production can be beneficial to threat inflammatory and autoimmune disorders.

Lymphocytes as liver damage mirror of HCV related adipogenesis deregulation

Hepatitis C virus infection leads to a wide spectrum of liver diseases ranging from mild chronic hepatitis to end-stage cirrhosis and hepatocellular carcinoma. An intriguing aspect of the HCV infection is its close connection with lipid metabolism playing an important role in the HCV life cycle and in its pathogenesis. HCV is known to be a hepatotropic virus; however, it can also infect peripheral blood mononuclear cells (PBMCs). The goal of the current investigation is to compare the adipogenesis profile of liver tissues to lymphocytes of HCV infected patients, in order to understand if PBMCs may reflect the alterations of intracellular pathways occurring during HCV-related liver steatosis. Using the Human Adipogenesis PCR Array, gene expression was analyzed in liver samples and PBMCs of chronic HCV+, HBV+ and Healthy Donors (HDs) patients. We observed a similar modulation of lipid metabolism in HCV+ and HBV+liver tissues and lymphoid, cells suggesting that PBMCs reflect the liver adipogenesis deregulation related to infection, even if the two viruses have a different impact in the regulation of the adipogenesis mechanisms. In particular, some genes involved in lipid metabolism and inflammation, as well as in cell transformation, were up-regulated, in a similar way, in both HCV models analyzed. Interestingly, these genes were positively correlated to virological and hepatic functional parameters of HCV+ patients. On the contrary, HBV+ patients displayed a completely different profile. PBMCs of HCV+ patients seem to be useful model to study how HCV-related lipid metabolism deregulation occurs in liver. The obtained data suggest some molecules as new possible biomarkers of HCV-related liver damage progression.

The hepatitis C virus infection as a systemic disease

Hepatitis C Virus (HCV) is a major health problem, infecting about 3 % of people worldwide and leading to liver as well as extrahepatic diseases. This justifies the definition of HCV infection as a systemic disease. Based on available data, the link between the virus and some of these extrahepatic disorders is certain, whereas for some others needs further confirmation. HCV-related lymphoproliferative disorders, ranging from benign, but pre-lymphomatous conditions, like mixed cryoglobulinemia, to frank lymphomas, represent the extrahepatic manifestations most closely related to HCV. The primary involvement of the liver and lymphatic system corresponds to the double viral tropism, being HCV able to infect both hepatic and lymphatic cells. Other HCV-associated disorders include renal, endocrine, dermatological, cardiovascular, rheumatologic and central nervous system diseases. On the whole, the HCV disease appears a very important, mainly hidden, public health problem leading to heavy direct and indirect costs. The possibility that HCV may be eradicated following antiviral therapy is important for both the therapeutic and preventive points of view, making the HCV disease an ideal model for pathogenetic studies.

Hepatitis C virus infection in the immunocompromised host: a complex scenario with variable clinical impact

The relationship between Hepatitis C Virus (HCV) infection and immunosuppression is complex and multifaceted. Although HCV-related hepatocytolysis is classically interpreted as secondary to the attack by cytotoxic T lymphocytes against infected cells, the liver disease is usually exacerbated and more rapidly evolutive in immunosuppressed patients. This generally occurs during the immunosuppression state, and not at the reconstitution of the host response after immunosuppressive therapy discontinuation. The field of immunosuppression and HCV infection is complicated both by the different outcome observed in different situations and/or by contrasting data obtained in the same conditions, with several still unanswered questions, such as the opportunity to modify treatment schedules in the setting of post-transplant follow-up. The complexity of this field is further complicated by the intrinsic tendency of HCV infection in itself to lead to disorders of the immune system. This review will briefly outline the current knowledge about the pathogenesis of both hepatic and extrahepatic HCV-related disorders and the principal available data concerning HCV infection in a condition of impairment of the immune system. Attention will be especially focused on some conditions - liver or kidney transplantation, the use of biologic drugs and cancer chemotherapy - for which more abundant and interesting data exist.

HCV and lymphoproliferation

Hepatitis C virus (HCV) infection is a serious public health problem because of its worldwide diffusion and sequelae. It is not only a hepatotropic but also a lymphotropic agent and is responsible not only for liver injury--potentially evolving to cirrhosis and hepatocellular carcinoma--but also for a series of sometimes severely disabling extrahepatic diseases and, in particular, B-cell lymphoproliferative disorders. These latter range from benign, but prelymphomatous conditions, like mixed cryoglobulinemia, to frank lymphomas. Analogously with Helicobacter pylori related lymphomagenesis, the study of the effects of viral eradication confirmed the etiopathogenetic role of HCV and showed it is an ideal model for better understanding of the molecular mechanisms involved. Concerning these latter, several hypotheses have been proposed over the past two decades which are not mutually exclusive. These hypotheses have variously emphasized the important role played by sustained stimulation of the immune system by HCV, infection of the lymphatic cells, viral proteins, chromosomal aberrations, cytokines, or microRNA molecules. In this paper we describe the main hypotheses that have been proposed with the corresponding principal supporting data.

FcRL4 acts as an adaptive to innate molecular switch dampening BCR signaling and enhancing TLR signaling

Fc receptor-like 4 (FcRL4) is expressed on the surface of a subset of memory B cells (MBCs) located at sites of invading pathogens in mucosal lymphoid tissues in healthy individuals. Recently, FcRL4(+) MBCs were shown to be greatly increased in number in the peripheral blood of HIV-infected viremic individuals, in whom they are associated with B-cell exhaustion, and in individuals chronically reinfected with malaria. In the present study, we provide evidence that the expression of FcRL4 in human B-cell lines disrupts immune synapse formation and blocks antigen-induced BCR signaling at the point of Syk phosphorylation, blocking downstream activation of PLC-γ2 and Vav and the induction of calcium responses and CD69 expression. FcRL4 functions by ligation-independent mechanisms that require the 3 tyrosine residues in its cytoplasmic domain and involves its phosphorylation and association with the tyrosine phosphatases SHP-1 and SHP-2. Remarkably, FcRL4 is concentrated in endosomes after treatment with the TLR9 agonist CpG and enhances signaling through TLR9, as measured by increased expression of CD23. These findings suggest that FcRL4 may act as a molecular switch in B cells to dampen adaptive immune signaling and enhance innate signaling in response to chronic antigenic stimulation.

HBV and HCV chronic infection: autoimmune manifestations and lymphoproliferation

Hepatitis B (HBV) and C (HCV) viruses differ both in viral structure and in natural history of chronic infection. However, they seem to share, although to a different extent, some characteristics, like the possibility to infect not only hepatic but also lymphatic cells and to associate with some hepatic and/or extrahepatic disorders of an autoimmune and/or lymphoproliferative nature. These characteristics have been more widely studied in the case of chronic HCV infection, where they are more evident, but they have been described also in the case of HBV infection.

Nonstructural 3/4A protease of hepatitis C virus activates epithelial growth factor-induced signal transduction by cleavage of the T-cell protein tyrosine phosphatase

The hepatitis C virus (HCV) is a worldwide major cause of chronic liver disease with a high tendency to establish a persistent infection. To permit persistent replication of viral genomes through the cellular translation machinery without affecting host cell viability, viruses must have developed mechanisms to control cellular cascades required for sufficient viral replication, on the one hand, and to adapt viral replication to the cellular requirements on the other hand. The present study aimed to further elucidate mechanisms by which HCV targets growth factor signaling of the host cell and their implications for viral replication. The study describes a novel mechanism by which HCV influences the activation of the epithelial growth factor receptor/Akt pathway through a nonstructural (NS)3/4A-dependent down-regulation of the ubiquitously expressed tyrosine phosphatase T cell protein tyrosine phosphatase (TC-PTP). NS3/4A is demonstrated to cleave TC-PTP protease-dependently in vitro at two cleavage sites. The in vivo relevance of this finding is supported by the fact that down-regulation of TC-PTP protein expression could also be demonstrated in HCV-infected individuals and in transgenic mice with intrahepatic expression of NS3/4A.

CONCLUSION

This down-regulation of TC-PTP results in an enhancement of epithelial growth factor (EGF)-induced signal transduction and increases basal activity of Akt, which is demonstrated to be essential for the maintenance of sufficient viral replication. Hence, therapeutic targeting of NS3/4A may not only disturb viral replication by blocking the processing of the viral polyprotein but also exerts unforeseen indirect antiviral effects, further diminishing viral replication.

Antiviral therapy after complete response to chemotherapy could be efficacious in HCV-positive non-Hodgkin's lymphoma

BACKGROUND/AIMS

Prevalence of HCV infection in non-Hodgkin's lymphoma is high. The impact of antiviral therapy on the natural history of this subgroup of lymphomas after a successful chemotherapy regimen is still an argument of debate.

METHODS

We retrospectively examined 343 chemotherapy-treated patients referred to our centre for five consecutive years. Clinical and histological characteristics, disease free-survival (DFS) and overall-survival (OS) were compared in HCV-positive (69/343) and HCV-negative (274/343) patients. Twenty-five HCV-positive patients received antiviral treatment following chemotherapy discontinuation. Uni- and multivariate analyses were performed.

RESULTS

20% of lymphomas were HCV-positive. Indolent histology was prevalent in the HCV-positive group (p<0.05); no significant differences in OS or DFS were found between the two groups; in HCV-positive subjects, antiviral therapy, was associated with a longer DFS (p<0.05); none of the HCV-positive subjects who achieved a virological response experienced any lymphoma relapse; 29% of non responders did; at multivariate analysis, the independent factors related to a better clinical outcome were: indolent histology at the onset of lymphoma and antiviral therapy.

CONCLUSIONS

Antiviral treatment in HCV-positive non-Hodgkin's lymphoma may be an important strategy to reinforce the results of a successful chemotherapy regimen; further studies are needed to validate this combined approach.