Small airway fibrosis is a common pathology of chronic obstructive pulmonary disease (COPD) and contributes to airflow obstruction. However, the underlying fibrogenic mechanism is poorly understood. Epithelial-mesenchymal transition (EMT) has been proposed as a driver of fibrosis. EMT occurs in the airways of COPD patients and smokers, but it remains elusive whether EMT may contribute to airway fibrosis. We previously reported that FBXO11 is a critical suppressor of EMT and Fbxo11 deficiency in mice causes neonatal lethality and EMT in epidermis. Here, we found that Fbxo11 -deficient mouse embryonic lungs showed impaired epithelial differentiation, excess fibroblast cells surrounding the airways, and thickened interstitial mesenchyme. We further generated conditional mutant mice to ablate Fbxo11 selectively in the club airway epithelial cells in adult mice, which induced partial EMT in the airways. To determine the effect of EMT on airway fibrosis, Fbxo11 conditional mutant mice were exposed to cigarette smoke. Airway-specific loss of Fbxo11 markedly enhanced smoking-induced airway fibrotic remodeling and collagen deposition. Taken together, our study suggests that EMT in the airway epithelium exacerbates cigarette smoke-induced airway fibrosis.

Gastric cancer (GC) is the fifth most common cancer worldwide and the third leading cause of global cancer-related death. Benzo[a]pyrene (BaP), a Group Ⅰ carcinogen categorized by the IARC, is a cumulative foodborne carcinogen and ubiquitous environmental pollutant with potent carcinogenic properties. However, the function and mechanism of BaP exposure on GC progression remains unclear. We investigated the role of BaP in human GC progression to identify potential mechanism underlining its carcinogenic activity. After exposure to various concentrations of BaP, human GC cells SGC-7901 and MNK-45 showed an increased capability of proliferation, migration and invasion. Further study indicated that BaP promotes the expression of matrix metalloproteinase-9 (MMP9) and c-myc at mRNA and protein level, and activates Aryl hydrocarbon receptor (AhR) and ERK pathway. Moreover, BaP-induced overexpression of MMP9 and c-myc were attenuated by the ERK inhibitor U0126 and AhR inhibitor resveratrol, respectively. These data suggest that BaP promotes proliferation and metastasis of GC cells through upregulation of MMP9 and c-myc expression, and this was likely mediated via the AhR and ERK signaling pathway.

Abstract Epithelial-to-mesenchymal transition (EMT) is central to embryonic development and carcinoma progression. The cell adhesion molecule E-cadherin critically maintains epithelial property and restricts epithelial cell proliferation and motility. The Snail family of transcription factors are core inducers of EMT in part through direct repression of E-cadherin transcription. The Snail factors are normally under tight control to safeguard epithelial identity and homeostasis. However, their physiological regulation remains largely elusive. In the present study, we show that the F-box protein FBXO11 binds to Snail in a phosphorylation-independent manner and targets it for ubiquitin-mediated proteasomal degradation. FBXO11 promotes the degradation of other Snail family members Slug and SCRT1 as well. Overexpression of FBXO11 in mesenchymal cells reduces Snail protein abundance and activates E-cadherin transcription. Conversely, depletion of endogenous FBXO11 in epithelial cancer cells causes Snail protein accumulation, EMT, and tumor invasion. Human cancer-derived FBXO11 missense mutants are impaired to degrade Snail. In human cancer, FBXO11 expression correlates with E-cadherin, and decreased expression of FBXO11 is robustly associated with adverse clinical outcomes. Inactivation of FBXO11 in mice results in neonatal lethality, increased Snail and Slug protein levels, decreased E-cadherin expression, and epidermal hyperplasia, which phenotypically resemble epidermis-specific transgenic overexpression of Snail or deletion of E-cadherin. These findings establish FBXO11 as a physiological ubiquitin ligase of Snails that is indispensable for suppressing epithelial hyperproliferation and plasticity during embryonic development and carcinoma progression. Note: This abstract was not presented at the meeting. Citation Format: Jianrong Lu, Yue Jin, Anitha K. Shenoy, Hao Chen, Huacheng Luo,Lizi Wu, Kamal A. Mohammed. FBXO11 suppresses epithelial plasticity and proliferation by ubiquitinating the Snail family of transcription factors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1425. doi:10.1158/1538-7445.AM2015-1425

Serine protease inhibitors (Serpins) play an important role in regulating a wide array of diverse biological activities, representing up to 2-10% of circulating plasma proteins. The serpin suicide inhibitors regulate coagulation (thrombosis and thrombolysis), neurotrophic factors, hormone transport, complement and inflammation, angiogenesis, hormone transport, and blood pressure among many other biological reactions. Select serpins have been associated with progression or remission of selected cancers, making them valuable for therapeutic or diagnostic use. Plasminogen activator inhibitor-1 (PAI-1), the main regulator of thrombolysis, has the potential to either reduce or accelerate tumor growth but blockade of PAI-1 has recently been reported to reduce cancer cell migration, proliferation and survival through modulating the function of urokinase-type plasminogen activator receptor. Maspin is a non-inhibitory serpin, that increases cancer cell sensitivity to apoptosis and inhibits cancer cell migration thus providing a serpin that blocks tumor gorwth. Pigment epithelium derived factor (PEDF) has potent anti-angiogenesis activity and also promotes cancer cell apoptosis. Among other serpins, the mammalian serpin, neuroserpin, and the myxomavirus derived serpin, Serp-1 are under investigation in our lab for their potential tumor-suppressive functions. Further study on the efficacy and mechanisms of serpin mediated anti-cancer activity is warranted in order to develop new serpin-based approaches in cancer therapy.

Serpins in the mammalian body are highly potent serine protease inhibitors which modulate both thrombotic and thrombolytic pathway activation, with direct and indirect crosstalk with immune and inflammatory pathways. In this review, we discuss mammalian and viral serpins as regulators of coagulation and inflammation. We focus first on the thrombotic and thrombolytic serine proteases and known interactions between these protease cascades and elements of the innate immune response. Serpin-mediated regulation of the thrombotic pathway is then discussed, with emphasis on those serpins that have been evaluated as potential new drugs. Finally the potential of viral serpins that target the coagulation and thrombolytic cascades as potential therapeutics for anti-inflammatory properties is discussed from basic molecular activity to studies in animal models. The studies discussed range from thrombosis and hemorrhage to vascular disease and transplant rejection and finally to sepsis and clinical studies in humans. In conclusion, these unique proteins, the serpin family, now have demonstrated therapeutic potential for a wide variety of inflammatory diseases in both animal and human studies and represent a new approach for drug development.

Lethal viral infections produce a cytokine storm with disseminated vascular leak, clotting, bleeding, organ failure and high mortality, but treatment remains limited. With this cytokine storm there is a massive influx of inflammatory macrophage and T lymphocytes into the arterial wall and affected organs. Serine proteases in clot-forming and clot-dissolving cascades are regulated by inhibitors termed serpins. Serpins such as anti-thrombin III have been used to reduce DIC and improve outcomes but with limited success. Myxomavirus secretes a potent anti-inflammatory serpin, Serp-1, that inhibits thrombotic factor Xa (fXa) and thrombolytic tissue and urokinase-type plasminogen activators (tPA, uPA). Serp-1 treatment was tested in mouse models of lethal gammaHerpesvirus68 and Ebola virus infections. Serp-1 significantly increased survival in both infections, whereas mammalian neuroserpin, that targets only tPA and uPA, did not. Fator Xa levels were reduced in aortic tissues after Serp-1 treatment. Serp-1 reduced virus load, hemorrhage, inflammation, and organ damage. NSP treatment allowed for a marked suppression of normal spleen cell responses during infections on flow cytometry analysis, while Serp-1 did not. RT-PCR array analysis of aortic sections from infected mice demonstrated significantly altered thrombotic and thrombolytic pathway proteases and serpins as well as addressin gene expression changes with Serp-1 treatment but not with NSP treatment. Treatments with other myxomaviral anti-inflammatory proteins, Serp-2 targeting apoptosis, and M-T7 a chemokine modulator showed trends toward reduced inflammation in the MHV68 infected mice. Conclusions: Myxomaviral Serp-1 modulates thrombotic and thrombolytic proteases, markedly improving survival in unrelated lethal viral infections, whereas a mammalian serpin targeting only thrombolysis was ineffective. Treatment targeting both thrombotic and the thrombolytic cascades may improve outcomes in severe viral septic states with vascular inflammation and DIC.

Inflammatory responses now have a defined central role in cancer cell growth, invasion, and metastases. Anti-inflammatory proteins from viruses target key stages in immune response pathways and have potential as novel therapeutics for cancer, including highly potent virus-derived inhibitors of protease, chemokine, cytokine, and apoptotic cascades that have been identified. Serine proteases, in addition to their conventional roles in thrombosis, thrombolysis, and apoptotic pathways, are essential regulators of inflammation and are associated with developing cancers. Chemokines drive other inflammatory response pathways with central roles in cell invasion and activation as well as establishing the microenvironment of tumors, modulating immune cell infiltration, cancer cell proliferation, metastasis, and angiogenesis. This review focuses on the mechanisms of action and potential for application of viral immunomodulatory proteins as anticancer therapeutics. Inflammatory responses now have a defined central role in cancer cell growth, invasion, and metastases. Anti-inflammatory proteins from viruses target key stages in immune response pathways and have potential as novel therapeutics for cancer, including highly potent virus-derived inhibitors of protease, chemokine, cytokine, and apoptotic cascades that have been identified. Serine proteases, in addition to their conventional roles in thrombosis, thrombolysis, and apoptotic pathways, are essential regulators of inflammation and are associated with developing cancers. Chemokines drive other inflammatory response pathways with central roles in cell invasion and activation as well as establishing the microenvironment of tumors, modulating immune cell infiltration, cancer cell proliferation, metastasis, and angiogenesis. This review focuses on the mechanisms of action and potential for application of viral immunomodulatory proteins as anticancer therapeutics.

Inflammatory responses now have a defined central role in cancer cell growth, invasion, and metastases. Anti-inflammatory proteins from viruses target key stages in immune response pathways and have potential as novel therapeutics for cancer, including highly potent virus-derived inhibitors of protease, chemokine, cytokine, and apoptotic cascades that have been identified. Serine proteases, in addition to their conventional roles in thrombosis, thrombolysis, and apoptotic pathways, are essential regulators of inflammation and are associated with developing cancers. Chemokines drive other inflammatory response pathways with central roles in cell invasion and activation as well as establishing the microenvironment of tumors, modulating immune cell infiltration, cancer cell proliferation, metastasis, and angiogenesis. This review focuses on the mechanisms of action and potential for application of viral immunomodulatory proteins as anticancer therapeutics.

Over the past 19 years, we have developed a novel myxoma virus-derived anti-inflammatory serine protease inhibitor, termed a serpin, as a new class of immunomodulatory therapeutic. This review will describe the initial identification of viral serpins with anti-inflammatory potential, beginning with preclinical analysis of viral pathogenesis and proceeding to cell and molecular target analyses, and successful clinical trial. The central aim of this review is to describe the development of two serpins, Serp-1 and Serp-2, as a new class of immune modulating drug, from inception to implementation.We begin with an overview of the approaches used for successful mining of the virus for potential serpin immunomodulators in viruses. We then provide a methodological overview of one inflammatory animal model used to test for serpin anti-inflammatory activity followed by methods used to identify cells in the inflammatory response system targeted by these serpins and molecular responses to serpin treatment. Finally, we provide an overview of our findings from a recent, successful clinical trial of the secreted myxomaviral serpin, Serp-1, in patients with unstable inflammatory coronary arterial disease.