LYP, a bestatin dimethylaminoethyl ester, inhibited cancer angiogenesis both in vitro and in vivo

Treatment with bestatin (the exogenous synthetic inhibitor of metalloproteinases) reduces the activity of metalloproteinase 2 and 12 in the spleen and lung tissues of rats in a model of lipopolysaccharide-induced sepsis

Sepsis is caused by an inadequate or dysregulated host response to infection. Enzymes causing cellular degradation are matrix metalloproteinases (MMPs). Lipopolysaccharide (LPS) is used in models of sepsis in laboratory settings The aim of the study was to measure MMP 2 and 12 concentrations in spleen and lungs in rats in which septic shock was induced by LPS. The experiment was carried out on 40 male Wistar rats (5 groups of 8): 0. controls 1. administered LPS 2. administered bestatin 3. LPS and bestatin 4.bestatin and after 6 hours LPS Animals were decapitated. Lungs and spleens were collected. Concentrations of MMP-2 and MMP-12 were determined using immunoenzymatic methods. Mean (±SD) MMP-2 in the controls was 43.57 ± 20.53 ng/ml in the lungs and 1.7 ± 0.72 ng/ml in the spleen; Group 1: 31.28 ± 13.13 ng/ml, 0.83 ± 0.8 ng/ml; Group 2: 44.24 ± 22.75 ng /ml, 1.01 ± 0.32 ng/ml; Group 3: 35.94 ± 15.13 ng/ml, 0.41 ± 0.03 ng/ml; Group 4:79.42 ± 44.70 ng/ml, 0.45 ± 0.15, respectively. Mean MMP-12 in controls was 19.79 ± 10.01 ng/ml in lungs and 41.13 ± 15.99 ng/ml in the spleen; Group 1:27.97 ± 15.1 ng/ml; 40.44 ± 11.2 ng/ml; Group 2: 37.93 ± 25.38 ng/ml 41.05 ± 18.08 ng/ml; Group 3: 40.59 ± 11.46 ng/ml, 35.16 ± 12.89 ng/ml; Group 4: 39.4 ± 17.83 ng/ml, 42.04 ± 12.35 ng/ml, respectively. CONCLUSIONS: 1. Bestatin reduces MMP 2 and 12 levels in spleen and lungs. 2. Treatment with bestatin minimizes the effect of LPS.

The mercapturic acid pathway

The mercapturic acid pathway is a major route for the biotransformation of xenobiotic and endobiotic electrophilic compounds and their metabolites. Mercapturic acids (N-acetyl-l-cysteine S-conjugates) are formed by the sequential action of the glutathione transferases, γ-glutamyltransferases, dipeptidases, and cysteine S-conjugate N-acetyltransferase to yield glutathione S-conjugates, l-cysteinylglycine S-conjugates, l-cysteine S-conjugates, and mercapturic acids; these metabolites constitute a "mercapturomic" profile. Aminoacylases catalyze the hydrolysis of mercapturic acids to form cysteine S-conjugates. Several renal transport systems facilitate the urinary elimination of mercapturic acids; urinary mercapturic acids may serve as biomarkers for exposure to chemicals. Although mercapturic acid formation and elimination is a detoxication reaction, l-cysteine S-conjugates may undergo bioactivation by cysteine S-conjugate β-lyase. Moreover, some l-cysteine S-conjugates, particularly l-cysteinyl-leukotrienes, exert significant pathophysiological effects. Finally, some enzymes of the mercapturic acid pathway are described as the so-called "moonlighting proteins," catalytic proteins that exert multiple biochemical or biophysical functions apart from catalysis.

13F-1, a novel 5-fluorouracil prodrug containing an Asn-Gly-Arg (NO2) COOCH3 tripeptide, inhibits human colonic carcinoma growth by targeting Aminopeptidase N (APN/CD13)

13F-1 is a 5-fluorouracil prodrug containing an Asn-Gly-Arg (NO2) COOCH3 tripeptide. 13F-1 might possess the activity against cancer growth by targeting Aminopeptidase N (APN/CD13). Our goal in this study was to evaluate the inhibitory effect of 13F-1 on the growth of human colonic carcinoma by both in vitro and in vivo studies. Experiments were performed in colonic carcinoma Colo205 cells, which highly express APN/CD13 on cell surface. The inhibition of 13F-1 on cancer cell growth was estimated by the colorimetric and clonogenic assays. The assays of Annexin V-FITC/PI and JC-1 fluorescence probe were employed to determine the apoptotic cells. Further experiment was performed in mice bearing Colo205 xenografts. 13F-1 was injected for three consecutive weeks. The specimens of Colo205 xenografts were removed for TUNEL staining and western blotting analysis. The expressions of APN/CD13 were analyzed by immunofluorescent flow cytometry and western blotting assays. 13F-1 significantly inhibited Colo205 cell proliferation. 13F-1 by injection delayed the expansion of Colo205 xenografts without significant toxicity to mice. The inhibitory effect of 13F-1 might arise from its role in apoptotic induction. Further analysis indicated that 13F-1 strongly inhibited APN/CD13 expression on cancer cell surface. In contrast, 5-FU did not affect APN/CD13 expression. These results indicated the mechanism of 13F-1 action that 13F-1׳s effect was associated with its role in suppression of APN/CD13 expression. Conclusion, 13F-1 could be developed as a promising agent for treatment of cancers with high expression of APN/CD13.

Antiangiogenic role of miR-361 in human umbilical vein endothelial cells: functional interaction with the peptide somatostatin

Somatostatin (SRIF) acts as antiangiogenic factor, but its role in the regulation of microRNAs (miRNAs) targeting proangiogenic factors is unknown. We used human umbilical vein endothelial cells (HUVEC) to investigate whether (1) miRNAs targeting proangiogenic factors are influenced by hypoxia, (2) their expression is regulated by SRIF, and (3) SRIF-regulated miRNAs affect HUVEC angiogenic phenotype. The involvement of signal transducer and activator of transcription (STAT) 3 and hypoxia inducible factor (HIF)-1 in miRNA effects was studied. Quantitative real-time PCR, Western blot, cell proliferation assays, and enzyme-linked immunosorbent assay (ELISA) were used. Using specific algorithms, three miRNAs (miR-17, miR-18b, and miR-361) were predicted to bind angiogenesis-associated factors including STAT3, HIF-1α, and vascular endothelial growth factor (VEGF). Hypoxia downregulates miR-17 and miR-361 without affecting miR-18b. SRIF restored decreased levels of miR-361 acting at the SRIF receptor sst(1). Downregulated miR-361 was also restored by HIF-1α inhibition with YC-1. Combined application of SRIF did not influence YC-1-induced miR-361 downregulation, suggesting that YC-1 and SRIF modulate miR-361 through a common mechanism involving HIF-1α. This possibility was confirmed by the result that HIF-1α activation in normoxia-downregulated miR-361 and that this downregulation was prevented by SRIF. miR-361 overexpression reduced hypoxia-induced cell proliferation and VEGF release indicating miR-361 involvement in the acquisition of an angiogenic phenotype by HUVEC. miR-361 effects on VEGF were enhanced by the coadministration of SRIF. Our results suggest that (1) SRIF regulates miR-361 expression through a control on HIF-1, (2) miR-361 affects HUVEC angiogenic phenotype, and (3) SRIF and miR-361 act cooperatively in limiting hypoxia-induced VEGF release.

Enzymatic processing of angiotensin peptides by human glomerular endothelial cells

The intraglomerular renin-angiotensin system (RAS) is linked to the pathogenesis of progressive glomerular diseases. Glomerular podocytes and mesangial cells play distinct roles in the metabolism of angiotensin (ANG) peptides. However, our understanding of the RAS enzymatic capacity of glomerular endothelial cells (GEnCs) remains incomplete. We explored the mechanisms of endogenous cleavage of ANG substrates in cultured human GEnCs (hGEnCs) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and isotope-labeled peptide quantification. Overall, hGEnCs metabolized ANG II at a significantly slower rate compared with podocytes, whereas the ANG I processing rate was comparable between glomerular cell types. ANG II was the most abundant fragment of ANG I, with lesser amount of ANG-(1-7) detected. Formation of ANG II from ANG I was largely abolished by an ANG-converting enzyme (ACE) inhibitor, whereas ANG-(1-7) formation was decreased by a prolylendopeptidase (PEP) inhibitor, but not by a neprilysin inhibitor. Cleavage of ANG II resulted in partial conversion to ANG-(1-7), a process that was attenuated by an ACE2 inhibitor, as well as by an inhibitor of PEP and prolylcarboxypeptidase. Further fragmentation of ANG-(1-7) to ANG-(1-5) was mediated by ACE. In addition, evidence of aminopeptidase N activity (APN) was demonstrated by detecting amelioration of conversion of ANG III to ANG IV by an APN inhibitor. While we failed to find expression or activity of aminopeptidase A, a modest activity attributable to aspartyl aminopeptidase was detected. Messenger RNA and gene expression of the implicated enzymes were confirmed. These results indicate that hGEnCs possess prominent ACE activity, but modest ANG II-metabolizing activity compared with that of podocytes. PEP, ACE2, prolylcarboxypeptidase, APN, and aspartyl aminopeptidase are also enzymes contained in hGEnCs that participate in membrane-bound ANG peptide cleavage. Injury to specific cell types within the glomeruli may alter the intrarenal RAS balance.