In this study, the chemical compositions of the ethanolic and aqueous extracts of the leaves of
Origanum syriacum
and
Salvia lanigera
were identified based on GC-MS spectrometric analyses. The in ...vitro anti-inflammatory potential of the different extracts was evaluated by determining the membrane stabilization of human red blood cells and the percent inhibition of the COX1/2, 5LOX, and sPLA
2
-V enzymes. Both ethanolic extracts showed maximum membrane stabilization (≤ 91%, at 100 μg/mL) compared to the aqueous extracts (≤ 45%) and the reference drug diclofenac sodium (90.75%). The membrane-stabilizing effects of the ethanolic extracts could be directly correlated to their anti-inflammatory activity. While both ethanolic fractions strongly inhibited the 5LOX and COX-1 enzymes at 100 μg/mL, only the
O. syriacum
ethanolic extract selectively inhibited sPLA
2
-V (99.35%, at 50 μg/mL). The differences in the pharmacological efficiencies of the different extracts could be attributed to the variation in their chemical compositions particularly the content of oxygenated monoterpenoids. Additionally, none of the ethanolic extracts demonstrated cytotoxicity to human colorectal cancer cell lines (HCT-116 and Lovo), even at the highest concentration tested (200 μg/mL). The safe profiles of these extracts towards the tested cell lines may be due to the absence of the toxic phthalic acid ester substances. Collectively, these findings clearly suggest that the studied ethanolic extracts of
O. syriacum
and
S. lanigera
can be considered interesting candidates for the treatment of human inflammatory diseases related to oxidative stress and microbial infections.
A novel protease inhibitor isolated from date palm Phoenix dactylifera (L.) flowers (PIDF) was purified and characterized. A heat and acidic treatment step followed by ethanol precipitation and ...reverse-phase high-performance chromatography was applied to purify this natural protease inhibitor to homogeneity with a single band of about 19 kDa. The stability study depicted that PIDF was fully stable at 40 °C and retained 65% of its initial activity after heating at 50 °C for 24 h. Its thermal stability at 70 °C was markedly enhanced by adding calcium, bovine serum albumin, and sorbitol as well as by metal divalent cations, especially Mg2+ and Hg2+. This protease inhibitor showed high inhibitory activity against therapeutic proteases, including pepsin, trypsin, chymotrypsin, and collagenase, and acted as a potent inhibitor of some commercial microbial proteases from Aspergillus oryzae, Bacillus. sp, and Bacillus licheniformis. Moreover, a potent antibacterial spectrum against Gram (+) and Gram (−) bacterial strains and an efficient antifungal effect were observed. Its cytotoxicity toward human colorectal cancer cell LoVo and HCT-116 lines suggested that PIDF could serve as a new therapeutic target inhibiting human colorectal cancer.
Among mammalian secreted phospholipases A2 (sPLA(2)s), the group X enzyme has the most potent hydrolyzing capacity toward phosphatidylcholine, the major phospholipid of cell membrane and ...lipoproteins. This enzyme has recently been implicated in chronic inflammatory diseases such as atherosclerosis and asthma and may also play a role in colon tumorigenesis. We show here that group X sPLA(2) mouse (m)GX is one of the most highly expressed PLA(2) in the mouse colon and that recombinant mouse and human enzymes stimulate proliferation and mitogen-activated protein kinase activation of various colon cell lines, including Colon-26 cancer cells. Among various recombinant sPLA(2)s, mGX is the most potent enzyme to stimulate cell proliferation. Based on the use of sPLA(2) inhibitors, catalytic site mutants, and small interfering RNA silencing of cytosolic PLA(2)alpha and M-type sPLA(2) receptor, we demonstrate that mGX promotes cell proliferation independently of the receptor and via its intrinsic catalytic activity and production of free arachidonic acid and lysophospholipids, which are mitogenic by themselves. mGX can also elicit the production of large amounts of prostaglandin E2 and other eicosanoids from Colon-26 cells, but these lipid mediators do not play a role in mGX-induced cell proliferation because inhibitors of cyclooxygenases and lipoxygenases do not prevent sPLA(2) mitogenic effects. Together, our results indicate that group X sPLA(2) may play an important role in colon tumorigenesis by promoting cancer cell proliferation and releasing various lipid mediators involved in other key events in cancer progression.
Three main targets were subjected for the most approved monoclonal antibodies (mAbs) in cancer therapy: EGFR in solid cancer, the clusters of differentiation in blood cancer and VEGF in angiogenesis. ...Meanwhile side effects, the elevated costs and resistance problems are limiting the efficiency of mAbs as targeted therapy. The combinatory therapy with chemo or radiotherapy has improved the efficiency of mAbs. The present review aims to shed more light on the immunotherapy and the related patents that were developed for cancer treatment.
Among mammalian secreted phospholipases A2 (sPLA2s), group X sPLA2 has the most potent hydrolyzing activity toward phosphatidylcholine and is involved in arachidonic acid (AA) release. Group X sPLA2 ...is produced as a proenzyme and contains a short propeptide of 11 amino acids ending with a dibasic motif, suggesting cleavage by proprotein convertases. Although the removal of this propeptide is clearly required for enzymatic activity, the cellular location and the protease(s) involved in proenzyme conversion are unknown. Here we have analyzed the maturation of group X sPLA2 in HEK293 cells, which have been extensively used to analyze sPLA2-induced AA release. Using recombinant mouse (PromGX) and human (ProhGX) proenzymes; HEK293 cells transfected with cDNAs coding for full-length ProhGX, PromGX, and propeptide mutants; and various permeable and non-permeable sPLA2 inhibitors and protease inhibitors, we demonstrate that group X sPLA2 is mainly converted intracellularly and releases AA before externalization from the cell. Most strikingly, the exogenous proenzyme does not elicit AA release, whereas the transfected proenzyme does elicit AA release in a way insensitive to non-permeable sPLA2 inhibitors. In transfected cells, a permeable proprotein convertase inhibitor, but not a non-permeable one, prevents group X sPLA2 maturation and partially blocks AA release. Mutations at the dibasic motif of the propeptide indicate that the last basic residue is required and sufficient for efficient maturation and AA release. All together, these results argue for the intracellular maturation of group X proenzyme in HEK293 cells by a furin-like proprotein convertase, leading to intracellular release of AA during secretion.
Background: Group X secreted phospholipase A2 is an enzyme produced as a proenzyme that plays an important role in arachidonic acid release.
Results: Group X phospholipase A2 is matured intracellularly by a furin-like proprotein convertase and releases arachidonic acid during secretion.
Conclusion: Group X phospholipase A2 can release arachidonic acid intracellularly.
Significance: Group X phospholipase A2 may produce lipid mediators during secretion.
Among secreted phospholipases A2 (sPLA2s), human group X sPLA2 (hGX sPLA2) is emerging as a novel attractive therapeutic target due to its implication in inflammatory diseases. To elucidate whether ...hGX sPLA2 plays a causative role in coronary artery disease (CAD), we screened the human
PLA2G10
gene to identify polymorphisms and possible associations with CAD end-points in a prospective study, Athero
Gene
. We identified eight polymorphisms, among which, one non-synonymous polymorphism R38C in the propeptide region of the sPLA2. The T-512C polymorphism located in the 5′ untranslated region was associated with a decreased risk of recurrent cardiovascular events during follow-up. The functional analysis of the R38C polymorphism showed that it leads to a profound change in expression and activity of hGX sPLA2, although there was no detectable impact on CAD risk. Due to the potential role of hGX sPLA2 in inflammatory processes, these polymorphisms should be investigated in other inflammatory diseases.
Cancer therapy is facing the big challenge of destroying selectively tumour cells without harming the normal tissues. Chemotherapy was trying from the beginning to kill malignant cells because of ...their proliferative activity since normal cells are in general quiescent. Meanwhile side effects were produced due to the destruction of some normal cells that need regular proliferation. The discovery of biomarkers led to the identification of molecular targets within tumour cells in order to kill them selectively. Chemistry followed the progress of biomarkers biotechnology by the production of target specific antagonists which were the subject of many patents. Meanwhile novel problems of tumour resistance appeared and made the battle against cancer a non stop development of new strategies and new weapons. As a consequence, paralleled activities of patenting biomarkers and chemical antagonists are continuously generated. The offer of chemistry does not actually limit the efficiency of Targeted therapy but the identification of biomarkers is still missing the exclusive specificity to tumour cells.
Many enzymes are involved in numerous pathologies which are related to metabolic reactions and inflammatory diseases such as pancreatic lipase, α-amylase, α-glucosidase and xanthine oxidase and ...secreted phospholipases A2 (Group IIA, V and X), respectively. Therefore, inhibiting these enzymes offer the potential to block production of more inflammatory substances and decrease the risk factors for cardiovascular diseases. The purpose of this study was to investigate some potent, bioavailable and selective inhibitors of some catalytic proteins implicated to metabolic syndrome and their antioxidant effects from various solvent extracts of R. frangula leaves. The anti-inflammatory, obesity, diabete and XO potentials were evaluated through analyses of inhibition activities of corresponding metabolites.The water extract exhibited an important inhibitory effect on human, dromedary and stingray sPLA2-G IIA achieved an IC50 of 0.16±0.06, 0.19±0.05 and 0.07±0.01 mg/mL, respectively. Likewise, the same fraction demonstrated the highest pancreatic lipase inhibitory activity using two different substrates. Indeed, 50% of dromedary pancreatic lipase inhibition was demonstrated for 5 min and 15 min using olive oil and TC4 substrates, respectively. Besides, it was established that methanolic extract had more effective inhibitory lipase activity than ORLISTAT used as a specific inhibitor of gastric, pancreatic and carboxyl ester lipase for treating obesity, with an IC50 of 5.51±0.27 and 91.46±2.3 µg/mL, respectively. In the case of α-amylase, α-glucosidase and xanthine oxidase, the crude methanolic extract showed a potential inhibitory effect with an IC50 of 45±3.45, 3±0.15 and 27±1.71 µg/mL, respectively. Conclusively, R. frangula leaves extracts showed a potential value of some sPLA2, some metabolic enzymes and XO inhibitors as anti-inflammatory and metabolic syndrome drugs.
The epidermal growth factor receptor (EGFR) harbors a calmodulin (CaM)‐binding domain (CaM‐BD) and a CaM‐like domain (CaM‐LD) upstream and downstream, respectively, of the tyrosine kinase (TK) ...domain. We demonstrate in this paper that deletion of the positively charged CaM‐BD (EGFR/CaM‐BD∆) inactivated the TK activity of the receptor. Moreover, deletion of the negatively charged CaM‐LD (EGFR/CaM‐LD∆), leaving a single negative residue (glutamate), reduced the activity of the receptor. In contrast, substituting the CaM‐LD with a histidine/valine‐rich peptide (EGFR/InvCaM‐LD) caused full inactivation. We also demonstrated using confocal microscopy and flow cytometry that the chimera EGFR‐green fluorescent protein (GFP)/CaM‐BD∆, the EGFR/CaM‐LD∆, and EGFR/InvCaM‐LD mutants all bind tetramethylrhodamine‐labelled EGF. These EGFR mutants were localized at the plasma membrane as the wild‐type receptor does. However, only the EGFR/CaM‐LD∆ and EGFR/InvCaM‐LD mutants appear to undergo ligand‐dependent internalization, while the EGFR‐GFP/CaM‐BD∆ mutant seems to be deficient in this regard. The obtained results and in silico modelling studies of the asymmetric structure of the EGFR kinase dimer support a role of a CaM‐BD/CaM‐LD electrostatic interaction in the allosteric activation of the EGFR TK.
Model of the asymmetric structure of the epidermal growth factor receptor kinase dimer showing that the calmodulin‐binding domain (blue surface) and calmodulin‐like domain (red surface) of apposed monomers are well positioned to establish electrostatic interaction. The model highlights the transmembrane‐juxtamembrane segments and the activator and receiver monomers in relaxed and activated states.
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