Leukotriene A4 hydrolase expression in PEL cells is regulated at the transcriptional level and leads to increased leukotriene B4 production

Molecular and Immunohistochemical Expression of LTA4H and FXR1 in Canine Oral Melanoma

Oral melanoma is a common canine tumor whose prognosis is considered ominous, but poorly predicted by histology alone. In the present study the gene and protein expression of Leukotriene A4 hydrolase (LTA4H) and Fragile-X-mental retardation-related protein1 (FXR1), both reported as related to metastatic potential in different tumors, were investigated in canine oral melanoma. The main aim of the study was to confirm and quantify the presence of LTA4H and FXR1 genes and protein in oral melanomas. A secondary aim was to investigate their association with histologic prognostic criteria (mitotic count, Ki-67 index). Formalin-fixed-paraffin-embedded canine oral melanomas (36) were collected and histopathological evaluation carried out. Immunolabelling for LTA4H and FXR1 and Ki-67 were performed. RT-PCR evaluated LTA4H and FXR1 gene expressions. Histologically, most tumors were epithelioid cell melanomas (19/36) and were amelanotic, mildly or moderately pigmented (5, 12 and 13/36 respectively), only 6 were highly pigmented. Mitotic count ranged 1-106, Ki-67 index ranged 4.5–52.3. Thirty-two (32/32) melanomas immunolabelled for LTA4H and 33/34 for FXR1. RT-PCR values ranged 0.76–5.11 ΔCt for LTA4H and 0.22–6.24 ΔCt for FXR1. Molecular and immunohistochemical expression of both LTA4H and FXR1 did not statically correlate with mitotic count or Ki-67 index. The present study demonstrates LTA4H and FXR1 gene and protein in canine oral melanoma, however their expression is apparently unrelated to histopathologic prognostic criteria. Although LTA4H and FXR1 seem unrelated to tumor behavior, their extensive expression in the present cohort of cases suggest that they may play a role in canine oral melanoma oncogenesis.

RNAseq analysis of treatment-dependent signaling changes during inflammation in a mouse cutaneous wound healing model

BACKGROUND

Despite proven therapeutic effects in inflammatory conditions, the specific mechanisms of phytochemical therapies are not well understood. The transcriptome effects of Traumeel (Tr14), a multicomponent natural product, and diclofenac, a non-selective cyclooxygenase (COX) inhibitor, were compared in a mouse cutaneous wound healing model to identify both known and novel pathways for the anti-inflammatory effect of plant-derived natural products.

METHODS

Skin samples from abraded mice were analyzed by single-molecule, amplification-free RNAseq transcript profiling at 7 points between 12 and 192 h after injury. Immediately after injury, the wounds were treated with either diclofenac, Tr14, or placebo control (n = 7 per group/time). RNAseq levels were compared between treatment and control at each time point using a systems biology approach.

RESULTS

At early time points (12-36 h), both control and Tr14-treated wounds showed marked increase in the inducible COX2 enzyme mRNA, while diclofenac-treated wounds did not. Tr14, in contrast, modulated lipoxygenase transcripts, especially ALOX12/15, and phospholipases involved in arachidonate metabolism. Notably, Tr14 modulated a group of cell-type specific markers, including the T cell receptor, that could be explained by an overarching effect on the type of cells that were recruited into the wound tissue.

CONCLUSIONS

Tr14 and diclofenac had very different effects on the COX/LOX synthetic pathway after cutaneous wounding. Tr14 allowed normal autoinduction of COX2 mRNA, but suppressed mRNA levels for key enzymes in the leukotriene synthetic pathway. Tr14 appeared to have a broad 'phytocellular' effect on the wound transcriptome by altering the balance of cell types present in the wound.

Thrombospondin-1 interactions regulate eicosanoid metabolism and signaling in cancer-related inflammation

The metabolism of arachidonic acid and other polyunsaturated fatty acids produces eicosanoids, a family of biologically active lipids that are implicated in homeostasis and in several pathologies that involve inflammation. Inflammatory processes mediated by eicosanoids promote carcinogenesis by exerting direct effects on cancer cells and by affecting the tumor microenvironment. Therefore, understanding how eicosanoids mediate cancer progression may lead to better approaches and chemopreventive strategies for the treatment of cancer. The matricellular protein thrombospondin-1 is involved in processes that profoundly regulate inflammatory pathways that contribute to carcinogenesis and metastatic spread. This review focuses on interactions of thrombospondin-1 and eicosanoids in the microenvironment that promote carcinogenesis and how the microenvironment can be targeted for cancer prevention to increase curative responses of cancer patients.

Leukotriene A4 hydrolase: an emerging target of natural products for cancer chemoprevention and chemotherapy

Cancer is the second leading cause of death worldwide and has become a global burden. It has long been known that inflammation is related to cancer, as inflammatory components have been identified in the tumor microenvironment and support tumor progression. Among the key inflammatory mediators, leukotrienes were found to be involved in cancer development. In particular, leukotriene B4, which is converted from leukotriene A4 by leukotriene A4 hydrolase (LTA4H), has been implicated in several types of cancer. In addition, LTA4H has attracted attention because of purported roles in inflammation and cancer development. Herein, we review the history of LTA4H, its emerging roles in cancer development, and the development of LTA4H inhibitors in cancer prevention and therapy.

Genetic regulation of expression of leukotriene A4 hydrolase

In chronic inflammatory lung disorders such as chronic obstructive pulmonary disease (COPD), the concurrent organ-specific and systemic inflammatory responses lead to airway remodelling and vascular dysfunction. Although a major common risk factor for COPD, cigarette smoke alone cannot explain the progression of this disease; there is increasing evidence that genetic predisposition also plays a role in COPD susceptibility and progression. A key enzyme in chronic lung inflammation is leukotriene A4 hydrolase (LTA4H). With its aminopeptidase activity, LTA4H degrades the neutrophil chemoattractant tripeptide PGP. In this study, we used the luciferase reporter gene analysis system and quantitative trait locus analysis to explore the impact of single-nucleotide polymorphisms (SNPs) in the putative promoter region of LTA4H on LTA4H expression. We show that not only is the putative promoter of LTA4H larger than previously reported but also that SNPs in the expanded promoter region regulate expression of LTA4H both in cell-based systems and in peripheral blood samples from human subjects. These findings provide significant evidence for an active region upstream of the previously reported LTA4H promoter, which may have implications related to ongoing inflammatory processes in chronic lung disease.

Primary effusion lymphoma: secretome analysis reveals novel candidate biomarkers with potential pathogenetic significance

Primary effusion lymphoma (PEL) is a rare B-cell neoplasm in which tumor cells are consistently infected by Kaposi's sarcoma-associated herpesvirus and usually grow in body cavities without tumor mass formation. To detect new proteins related to pathogenesis, four established cell lines from PEL (CRO-AP2, CRO-AP3, CRO-AP5, and CRO-AP6) were characterized by proteomics analysis of the secretome. The secretomes were analyzed using two complementary mass spectrometry platforms: liquid chromatography-mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight-based approaches. Among 266 proteins identified from the proteomics analysis, 139 were considered as predicted secreted. Twenty proteins were specifically secreted by PEL cell lines after comparison with secretomes of human cell lines representative of diverse solid tumors and leukemias. More important, 27 additional proteins were shared by all CRO-AP PEL cell lines. The presence of these proteins was confirmed by IHC in CRO-AP cell lines and in six other PEL cell lines, four PEL clinical samples, and three extracavitary Kaposi's sarcoma-associated herpesvirus-positive solid lymphomas included for comparative analysis. Functional classification showed that PEL cell secretomes were enriched in proteins specifically involved in inflammation/immune response, growth/cell cycle, and mRNA processing, in addition to structural/matrix proteins and proteins with enzymatic activity.

Kaposi's sarcoma-associated herpesvirus latency in endothelial and B cells activates gamma interferon-inducible protein 16-mediated inflammasomes

Kaposi's sarcoma-associated herpesvirus (KSHV) infections of endothelial and B cells are etiologically linked with Kaposi's sarcoma (KS) and primary effusion B-cell lymphoma (PEL), respectively. KS endothelial and PEL B cells carry multiple copies of the nuclear episomal latent KSHV genome and secrete a variety of inflammatory cytokines, including interleukin-1β (IL-1β) and IL-18. The maturation of IL-1β and IL-18 depends upon active caspase-1, which is regulated by a multiprotein inflammasome complex induced by sensing of danger signals. During primary KSHV infection of endothelial cells, acting as a nuclear pattern recognition receptor, gamma interferon-inducible protein 16 (IFI16) colocalized with the KSHV genome in the nuclei and interacted with ASC and procaspase-1 to form a functional inflammasome (Kerur N et al., Cell Host Microbe 9:363-375, 2011). Here, we demonstrate that endothelial telomerase-immortalized human umbilical cells (TIVE) supporting KSHV stable latency (TIVE-LTC cells) and PEL (cavity-based B-cell lymphoma 1 [BCBL-1]) cells show evidence of inflammasome activation, such as the activation of caspase-1 and cleavage of pro-IL-1β and pro-IL-18. Interaction of ASC with IFI16 but not with AIM2 or NOD-like receptor P3 (NLRP3) was detected. The KSHV latency-associated viral FLIP (vFLIP) gene induced the expression of IL-1β, IL-18, and caspase-1 mRNAs in an NF-κB-dependent manner. IFI16 and cleaved IL-1β were detected in the exosomes released from BCBL-1 cells. Exosomal release could be a KSHV-mediated strategy to subvert IL-1β functions. In fluorescent in situ hybridization analyses, IFI16 colocalized with multiple copies of the KSHV genome in BCBL-1 cells. IFI16 colocalization with ASC was also detected in lung PEL sections from patients. Taken together, these findings demonstrated the constant sensing of the latent KSHV genome by IFI16-mediated innate defense and unraveled a potential mechanism of inflammation induction associated with KS and PEL lesions.

Rapid, non-targeted discovery of biochemical transformation and biomarker candidates in oncovirus-infected cell lines using LAESI mass spectrometry

Finding insights into how viruses hijack metabolic processes and biomarkers for viral diseases often require hypotheses about target compounds and/or labelling techniques. Here we present a method based on laser ablation electrospray ionization mass spectrometry to rapidly identify potential protein and metabolite biomarkers of oncovirus infection in B lymphocytes.

Characterization of bovine immortalized luteal endothelial cells: action of cytokines on production and content of arachidonic acid metabolites

BACKGROUND

The interactions between luteal, vascular endothelial, immune cells and its products: steroids, peptide hormones, prostaglandins (PGs), growth factors and cytokines play a pivotal role in the regulation of corpus luteum (CL) function. Luteal endothelial cells undergo many dynamic morphological changes and their action is regulated by cytokines. The aims are: (1) to establish in vitro model for bovine luteal endothelial cells examination; (2) to study the effect of cytokines: tumor necrosis factor alpha (TNFalpha) and interferon gamma (IFNgamma) on cell viability, leukotrienes (LTs) and PG synthases, and endothelin-1 (EDN-1) mRNA, protein expression and their secretion in bovine immortalized luteal endothelial (EnCL-1) cells.

METHODS

The primary cultures of bovine luteal endothelial cells were immortalized by transfection with vector carrying the Simian virus 40 T-antigen (SV40 T-ag) sequence. Expression of SV40 T-ag gene in EnCL-1 cells was confirmed by RT-PCR and immunofluorescence staining showed the presence of endothelial cell markers: VE-cadherin and von Willebrand factor. EnCL-1 cells were stimulated by TNFalpha with IFNgamma (50 ng/ml each) for 24 h. Cell viability, mRNA expression (real time RT-PCR), protein expression (western blotting) for LTC4 synthase (LTC4S), LTA4 hydrolase (LTA4H), PGE2 and PGF2alpha synthases and endothelin-1 (EDN-1), and levels of LTs (B4 and C4) and PGs (E2 and F2alpha) and EDN-1 in the medium (EIA) were evaluated.

RESULTS

We received immortalized luteal endothelial cell line (EnCL-1). Cytokines did not change EnCL-1 cell viability but increased mRNA expression of LTC4S, LTA4H, PGE2 and PGF2alpha synthases and EDN-1. EDN-1/2/3, LTC4 and PGF2alpha synthases protein expression were elevated in the presence of TNFalpha/IFNgamma, and accompanied by increased EDN-1, LTC4 and PGF2alpha secretion. Cytokines had no effect on PGES and LTA4H protein expression, and PGE2 and LTB4 release.

CONCLUSIONS

TNFalpha and IFNgamma modulate EnCL-1 cell function. Moreover, established EnCL-1 cell line appears to be a good model for investigating the molecular mechanisms related to cytokines action and aa metabolites production in cattle.

Primary effusion lymphoma: genomic profiling revealed amplification of SELPLG and CORO1C encoding for proteins important for cell migration

Primary effusion lymphoma (PEL) is associated with Kaposi sarcoma herpesvirus (KSHV) but its pathogenesis is poorly understood. Many KSHV-associated products can deregulate cellular pathways commonly targeted in cancer. However, KSHV infection alone is insufficient for malignant transformation. PEL also lacks the chromosomal translocations seen in other lymphoma subtypes. We investigated 28 PELs and ten PEL cell lines by 1 Mb resolution array comparative genomic hybridization (CGH) and found frequent gains of 1q21-41 (47%), 4q28.3-35 (29%), 7q (58%), 8q (63%), 11 (32%), 12 (61%), 17q (29%), 19p (34%), and 20q (34%), and losses of 4q (32%), 11q25 (29%), and 14q32 (63%). Recurrent focal amplification was seen at several regions on chromosomes 7, 8, and 12. High-resolution chromosome-specific tile-path array CGH confirmed these findings, and identified selectin-P ligand (SELPLG) and coronin-1C (CORO1C) as the targets of a cryptic amplification at 12q24.11. Interphase FISH and quantitative PCR showed SELPLG/CORO1C amplification (>4 extra copies) and low levels of copy number gain (1-4 extra copies) in 23% of PELs, respectively. Immunohistochemistry revealed strong expression of both SELPLG and coronin-1C in the majority of PELs, irrespective of their gene dosage. SELPLG is critical for cell migration and chemotaxis, while CORO1C regulates actin-dependent processes, thus important for cell motility. Their overexpression in PEL is expected to play an important role in its pathogenesis.

[6]-Gingerol suppresses colon cancer growth by targeting leukotriene A4 hydrolase

[6]-Gingerol, a natural component of ginger, exhibits anti-inflammatory and antitumorigenic activities. Despite its potential efficacy in cancer, the mechanism by which [6]-gingerol exerts its chemopreventive effects remains elusive. The leukotriene A(4) hydrolase (LTA(4)H) protein is regarded as a relevant target for cancer therapy. Our in silico prediction using a reverse-docking approach revealed that LTA(4)H might be a potential target of [6]-gingerol. We supported our prediction by showing that [6]-gingerol suppresses anchorage-independent cancer cell growth by inhibiting LTA(4)H activity in HCT116 colorectal cancer cells. We showed that [6]-gingerol effectively suppressed tumor growth in vivo in nude mice, an effect that was mediated by inhibition of LTA(4)H activity. Collectively, these findings indicate a crucial role of LTA(4)H in cancer and also support the anticancer efficacy of [6]-gingerol targeting of LTA(4)H for the prevention of colorectal cancer.