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.

In silico molecular docking of quercetin as anti-colorectal cancer agents by inhibiting LT4AH

Colorectal cancer is a malignant neoplasm originating from the colon or rectum. Overexpression of leukotriene A4 hydrolase (LTA4H) increases the growth of HCT116 colon cancer cells, therefore, this enzyme becomes an attractive target for commercial drug bestatin. Meanwhile, quercetin is a member of flavonoids possessing a wide variety of anticancer. This study aimed to determine the potential of quercetin as anti-colorectal cancer by inhibiting LTA4H through in silico molecular docking. The docking process involved optimizing quercetin structure, preparing LTA4H protein (PDB ID: 3U9W), validating the molecular docking method, and docking quercetin and bestatin on LTA4H. The binding energy of quercetin to LTA4H was -9.57 kcal/mol, while 28P native ligand and bestatin yielded -10.22 kcal/mol and -9.10 kcal/mol, respectively. Based on the binding energy value, quercetin has a potential inhibitory against the LTA4H.

A clinical perspective of soluble epoxide hydrolase inhibitors in metabolic and related cardiovascular diseases

: Epoxide hydrolase (EH) is a crucial enzyme responsible for catabolism, detoxification, and regulation of signaling molecules in various organisms including human beings. In mammals, EHs are classified according to their DNA sequence, sub-cellular location, and activity into eight major classes: soluble EH (sEH), microsomal EH (mEH), leukotriene A4 hydrolase (LTA4H), cholesterol EH (ChEH), hepoxilin EH, paternally expressed gene 1 (peg1/MEST), EH3 and EH4. The sEH, an α/β-hydrolase fold family enzyme is an emerging pharmacological target in multiple diseases namely, cardiovascular disease, neurodegenerative disease, chronic pain, fibrosis, diabetes, pulmonary diseases, and immunological disease. It exhibits prominent physiological effect that includes anti-inflammatory, anti-migratory and vasodilatory effects. Its efficacy has been documented in several kinds of clinical trials and observational studies. This review specifically highlights the development of soluble epoxide hydrolase inhibitors (sEHIs) in the clinical setting for the management of metabolic syndrome and related disorders such as cardiovascular effects, endothelial dysfunction, arterial disease, hypertension, diabetes, obesity, heart failure, and dyslipidemia. In addition, limitations and future aspects of sEHIs have also been highlighted which will help the investigators to bring the sEHI to the clinics.

Elevated cerebrospinal fluid cytokine levels in tuberculous meningitis predict survival in response to dexamethasone

Adjunctive treatment with antiinflammatory corticosteroids like dexamethasone increases survival in tuberculosis meningitis. Dexamethasone responsiveness associates with a C/T variant in Leukotriene A4 Hydrolase (LTA4H), which regulates expression of the proinflammatory mediator leukotriene B4 (LTB4). TT homozygotes, with increased expression of LTA4H, have the highest survival when treated with dexamethasone and the lowest survival without. While the T allele is present in only a minority of the world’s population, corticosteroids confer modest survival benefit worldwide. Using Bayesian methods, we examined how pretreatment levels of cerebrospinal fluid proinflammatory cytokines affect survival in dexamethasone-treated tuberculous meningitis. LTA4H TT homozygosity was associated with global cytokine increases, including tumor necrosis factor. Association between higher cytokine levels and survival extended to non-TT patients, suggesting that other genetic variants may also induce dexamethasone-responsive pathological inflammation. These findings warrant studies that tailor dexamethasone therapy to pretreatment cerebrospinal fluid cytokine concentrations, while searching for additional genetic loci shaping the inflammatory milieu.

A Bayesian analysis of the association between Leukotriene A4 Hydrolase genotype and survival in tuberculous meningitis

Tuberculous meningitis has high mortality, linked to excessive inflammation. However, adjunctive anti-inflammatory corticosteroids reduce mortality by only 30%, suggesting that inflammatory pathophysiology causes only a subset of deaths. In Vietnam, the survival benefit of anti-inflammatory corticosteroids was most pronounced in patients with a C/T promoter variant in the leukotriene A4 hydrolase (LTA4H) gene encoding an enzyme that regulates inflammatory eicosanoids. LTA4H TT patients with increased expression had increased survival, consistent with corticosteroids benefiting individuals with hyper-inflammatory responses. However, an Indonesia study did not find an LTA4H TT genotype survival benefit. Here using Bayesian methods to analyse both studies, we find that LTA4H TT genotype confers survival benefit that begins early and continues long-term in both populations. This benefit is nullified in the most severe cases with high early mortality. LTA4H genotyping together with disease severity assessment may target glucocorticoid therapy to patients most likely to benefit from it.