Cell phenotype determines PAI-1 antiproliferative effect - suppressed proliferation of the lung cancer but not prostate cancer cells

Wstęp: Inhibitor aktywatora plazminogenu typu 1 (PAI-1) jest ważnym regulatorem procesu wzrostu guza i tworzenia przerzutów nowotworowych, działając poprzez bezpośrednie hamowanie urokinazy (mechanizm antyfibrynolityczny) oraz niezależnie od kinaz poprzez powinowactwo z witronektyną. Autorzy pracy w poprzednim badaniu wykazali, że PAI-1 modyfikuje aktywność angiogenną komórek śródbłonka w stopniu zależnym od jego stężenia, jak również fenotypu komórek. Celem niniejszej pracy była ocena wpływu PAI-1 na aktywność proliferacyjną linii komórek nowotworowych - raka płuca (A549) i raka gruczołu krokowego (DU145), a także komórek strukturalnych - śródbłonka naczyniowego (HUVEC). Wyniki: Zmutowana postać PAI-1 (1, 10, 100 &#956;g/ml) charakteryzująca się znacząco przedłużoną aktywnością antyfibrynolityczną (T1/2 ~ 7000 godz.) w stopniu wyraźnie zależnym od dawki (p < 0,001) i czasu (p < 0,001) znamiennie hamowała aktywność proliferacyjną komórek raka płuca A549. Natomiast istotny wpływ PAI-1 na aktywność proliferacyjną komórek raka gruczołu krokowego DU145 wykazano tylko dla najwyższego użytego stężenia (100 &#956;g/ml) i tylko po 72 godzinach zahodowli (p < 0,001). Aktywność proliferacyjna komórek śródbłonka (HUVEC) była hamowana jedynie przez dawkę 100 &#956;g/ml PAI-1 po 24, 48 i 72 godzinach hodowli. Wniosek: Inhibitor aktywatora plazminogenu typu 1 moduluje aktywność proliferacyjną komórek w mechanizmie hamowania urokinazy w stopniu ściśle zależnym od fenotypu komórek, czasu działania i dawki. Pneumonol. Alergol. Pol. 2010; 78, 4: 279-283Introduction: Plasminogen inhibitor activator type 1 (PAI-1) is an important regulator of tumor growth and metastasis formation acting directly via specific urokinase complexing or indirectly due to its affinity to vitronectin. We have shown previously that PAI-1 modifies angiogenic activity of endothelial cells in a dose-dependent manner but also in close relationship to the cell phenotype. Present study aimed on evaluating the PAI-1 effect on the proliferative activity of lung cancer cells (A549), prostate cancer cells (DU145) as well as endothelial cells (HUVEC). Results: Mutated PAI-1 (1, 10, 100 &#956;g/mL) characterized by the prolonged antifibrinolytic activity (T1/2 ~ 7000 h) inhibited proliferation of lung cancer A549 cells in a dose-dependent (p < 0.001) and time-dependent (p < 0.001) manner. No significant effect on the DU145 prostate cancer cells has been observed except of the 72 h cultures with highest PAI-1 concentration (100 &#956;g/ml) (p < 0.001). Proliferative activity of endothelial cells (HUVEC) was affected by 100 &#956;g/ml PAI-1 only, and independent of the culture period (24, 48 and 72 h, p < 0.001). Conclusion: Plasminogen inhibitor activator type 1 modulates cell proliferation via antifibrynolitic mechanizm time- and dose-dependently, however final outcome is strongly affected by the cell phenotype. Pneumonol. Alergol. Pol. 2010; 78, 4: 279-28

Expression of an 8R-Lipoxygenase From the Coral Plexaura homomalla

© 2018 Elsevier Inc. Methods are presented for the use of the coral 8R-lipoxygenase from the Caribbean sea whip coral Plexaura homomalla as a model enzyme for structural studies of animal lipoxygenases. The 8R-lipoxygenase is remarkably stable and can be stored at 4°C for 3 months with virtually no loss of activity. In addition, an engineered “pseudo wild-type” enzyme is soluble in the absence of detergents, which helps facilitate the preparation of enzyme:substrate complexes

Structure Based Design and Synthesis of Peptide Inhibitor of Human LOX-12: In Vitro and In Vivo Analysis of a Novel Therapeutic Agent for Breast Cancer

Human breast cancer cell proliferation involves a complex interaction between growth factors, steroid hormones and peptide hormones. The interaction of growth factors, such as epidermal growth factor (EGF), with their receptors on breast cancer cells can lead to the hydrolysis of phospholipids and release of fatty acid such as arachidonic acid, which can be further metabolized by cyclooxygenase (COX) and lipoxygenase (LOX) pathways to produce prostaglandins. The high concentration of prostaglandins has been associated with chronic inflammatory diseases and several types of human cancers. This is due to the over expression COX, LOX and other inflammatory enzymes. Ten peptides were designed and synthesized by solid phase peptide synthesis and analyzed in vitro for enzyme inhibition. Out of these peptides, YWCS had shown significant inhibitory effects. The dissociation constant (KD) was determined by surface plasmon resonance (SPR) analysis and was found to be 3.39×10−8 M and 8.6×10−8 M for YWCS and baicalein (positive control), respectively. The kinetic constant Ki was 72.45×10−7 M as determined by kinetic assay. The peptide significantly reduced the cell viability of estrogen positive MCF-7 and estrogen negative MDA-MB-231 cell line with the half maximal concentration (IC50) of 75 µM and 400 µM, respectively. The peptide also induced 49.8% and 20.8% apoptosis in breast cancer cells MCF-7 and MDA-MB-231, respectively. The YWCS was also found to be least hemolytic at a concentration of 358 µM. In vivo studies had shown that the peptide significantly inhibits tumor growth in mice (p<0.017). This peptide can be used as a lead compound and complement for ongoing efforts to develop differentiation therapies for breast cancer

Characterization of Aptamer-Protein Complexes by X-ray Crystallography and Alternative Approaches

Aptamers are oligonucleotide ligands, either RNA or ssDNA, selected for high-affinity binding to molecular targets, such as small organic molecules, proteins or whole microorganisms. While reports of new aptamers are numerous, characterization of their specific interaction is often restricted to the affinity of binding (KD). Over the years, crystal structures of aptamer-protein complexes have only scarcely become available. Here we describe some relevant technical issues about the process of crystallizing aptamer-protein complexes and highlight some biochemical details on the molecular basis of selected aptamer-protein interactions. In addition, alternative experimental and computational approaches are discussed to study aptamer-protein interactions.

Progress in rational methods of cryoprotection in macromolecular crystallography

Measurements of the average thermal contractions (294→72 K) of 26 different cryosolutions are presented and discussed in conjunction with other recent advances in the rational design of protocols for cryogenic cooling in macromolecular crystallography

Rational Design and Characterization of D-Phe-Pro-D-Arg-Derived Direct Thrombin Inhibitors

The tremendous social and economic impact of thrombotic disorders, together with the considerable risks associated to the currently available therapies, prompt for the development of more efficient and safer anticoagulants. Novel peptide-based thrombin inhibitors were identified using in silico structure-based design and further validated in vitro. The best candidate compounds contained both l- and d-amino acids, with the general sequence d-Phe(P3)-Pro(P2)-d-Arg(P1)-P1′-CONH2. The P1′ position was scanned with l- and d-isomers of natural or unnatural amino acids, covering the major chemical classes. The most potent non-covalent and proteolysis-resistant inhibitors contain small hydrophobic or polar amino acids (Gly, Ala, Ser, Cys, Thr) at the P1′ position. The lead tetrapeptide, d-Phe-Pro-d-Arg-d-Thr-CONH2, competitively inhibits α-thrombin's cleavage of the S2238 chromogenic substrate with a Ki of 0.92 µM. In order to understand the molecular details of their inhibitory action, the three-dimensional structure of three peptides (with P1′ l-isoleucine (fPrI), l-cysteine (fPrC) or d-threonine (fPrt)) in complex with human α-thrombin were determined by X-ray crystallography. All the inhibitors bind in a substrate-like orientation to the active site of the enzyme. The contacts established between the d-Arg residue in position P1 and thrombin are similar to those observed for the l-isomer in other substrates and inhibitors. However, fPrC and fPrt disrupt the active site His57-Ser195 hydrogen bond, while the combination of a P1 d-Arg and a bulkier P1′ residue in fPrI induce an unfavorable geometry for the nucleophilic attack of the scissile bond by the catalytic serine. The experimental models explain the observed relative potency of the inhibitors, as well as their stability to proteolysis. Moreover, the newly identified direct thrombin inhibitors provide a novel pharmacophore platform for developing antithrombotic agents by exploring the conformational constrains imposed by the d-stereochemistry of the residues at positions P1 and P1′

Immune response modulation by curcumin in a latex allergy model

BACKGROUND: There has been a worldwide increase in allergy and asthma over the last few decades, particularly in industrially developed nations. This resulted in a renewed interest to understand the pathogenesis of allergy in recent years. The progress made in the pathogenesis of allergic disease has led to the exploration of novel alternative therapies, which include herbal medicines as well. Curcumin, present in turmeric, a frequently used spice in Asia has been shown to have anti-allergic and inflammatory potential. METHODS: We used a murine model of latex allergy to investigate the role of curcumin as an immunomodulator. BALB/c mice were exposed to latex allergens and developed latex allergy with a Th2 type of immune response. These animals were treated with curcumin and the immunological and inflammatory responses were evaluated. RESULTS: Animals exposed to latex showed enhanced serum IgE, latex specific IgG(1), IL-4, IL-5, IL-13, eosinophils and inflammation in the lungs. Intragastric treatment of latex-sensitized mice with curcumin demonstrated a diminished Th2 response with a concurrent reduction in lung inflammation. Eosinophilia in curcumin-treated mice was markedly reduced, co-stimulatory molecule expression (CD80, CD86, and OX40L) on antigen-presenting cells was decreased, and expression of MMP-9, OAT, and TSLP genes was also attenuated. CONCLUSION: These results suggest that curcumin has potential therapeutic value for controlling allergic responses resulting from exposure to allergens

Curcumin activates the p38MPAK-HSP25 pathway in vitro but fails to attenuate diabetic nephropathy in DBA2J mice despite urinary clearance documented by HPLC

<p>Abstract</p> <p>Background</p> <p>Curcumin has anti-inflammatory, anti-oxidant, and anti-proliferative properties, and depending upon the experimental circumstances, may be pro- or anti-apoptotic. Many of these biological actions could ameliorate diabetic nephropathy.</p> <p>Methods/Design</p> <p>Mouse podocytes, cultured in basal or high glucose conditions, underwent acute exposure to curcumin. Western blots for p38-MAPK, COX-2 and cleaved caspase-3; isoelectric focusing for HSP25 phosphorylation; and DNase I assays for F- to G- actin cleavage were performed for <it>in vitro </it>analyses. <it>In vivo </it>studies examined the effects of dietary curcumin on the development of diabetic nephropathy in streptozotocin (Stz)-induced diabetes in DBA2J mice. Urinary albumin to creatinine ratios were obtained, high performance liquid chromatography was performed for urinary curcuminoid measurements, and Western blots for p38-MAPK and total HSP25 were performed.</p> <p>Results</p> <p>Curcumin enhanced the phosphorylation of both p38MAPK and downstream HSP25; inhibited COX-2; induced a trend towards attenuation of F- to G-actin cleavage; and dramatically inhibited the activation of caspase-3 in <it>vitro</it>. In curcumin-treated DBA2J mice with Stz-diabetes, HPLC measurements confirmed the presence of urinary curcuminoid. Nevertheless, dietary provision of curcumin either before or after the induction of diabetes failed to attenuate albuminuria.</p> <p>Conclusions</p> <p>Apart from species, strain, early differences in glycemic control, and/or dosing effects, the failure to modulate albuminuria may have been due to a decrement in renal HSP25 or stimulation of the 12/15 lipoxygenase pathway in DBA2J mice fed curcumin. In addition, these studies suggest that timed urine collections may be useful for monitoring curcumin dosing and renal pharmacodynamic effects.</p