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[en] The serine protease uPA and its inhibitor PAI-1 are involved in the degradation of tumor stroma and basement membrane. The independent prognostic value of serine protease urokinase-type plasminogen activator uPA and its inhibitor PAI-1 in breast cancer has been almost uniformly confirmed in numerous individual studies as well as in a meta-analysis, including 18 data sets of more than 8,000 patients. According to these observations, the risk of relapse in node negative patients with low levels of uPA and PAI-1 is less then 10%; these patients could be spared from toxic adjuvant systemic therapy. Clinically relevant and even more important is the information that uPA and its inhibitor PAI-1 may also have a predictive value for response to either hormonal or cytotoxic therapy in early breast cancer. According to our data obtained from altogether 460 operable breast cancer patients, uPA and PAI-1 may have a predictive value for the response to hormone therapy, but not to chemotherapy. The high PAI-1 levels were associated with a higher risk of relapse in the patients without adjuvant systemic therapy (HR 2.14; C.I. 95%0.48-9.56; p=0.321) and in the patients treated with chemotherapy (RR 2.48; C.I. 95%= 1.35-4.57; p=0.003). However, in the patients treated with adjuvant hormone therapy, either alone or in combination with chemotherapy, the prognostic value of uPA and PAI-1 was diminished. Moreover, high levels of both uPA and PAI-1 were associated with a lower risk of relapse (HR 0.79; p=0.693 and HR 0.26 p= 0.204, respectively). On the basis of currently available evidence, serine protease uPA and its inhibitor PAI-1 are certainly the markers that improve a proper selection of candidates for adjuvant systemic therapy and may also be the markers that could facilitate treatment decision in each individual patient, which is of utmost importance. (author)
[en] Full text: The emergence of homochirality in living systems is not fully explained. Why is it that L-amino acids and D-sugars predominate in living organisms? Cooks et al. and Hodyss et al. have reported a strong chirality preference in clusters of serine. In their studies, they propose that serine could be the original chiral progenitor. Recently our group has performed the first measurements with L-serine in cold He nanodroplets. The nanodroplets are produced by supersonic expansion and then doped with L-serine monomers generated by heating solid L-serine. The serine-doped helium droplets are then probed by electron impact ionization mass spectrometry. We have studied clustering of serine in the nanodroplets and observe with decreasing droplet size a profound change in the shape of the serine cluster distribution. For this case we observe a distinct magic peak for Ser8H+ and also a magic peak for the protonated dimer Ser2H+. Possible explanations for such a pronounced cluster distribution will be discussed. (author)
[en] Metabolic reprogramming is an essential hallmark of neoplasia. Therefore, targeting cancer metabolism, including lipid synthesis, has attracted much interest in recent years. Serine palmitoyltransferase (SPT) plays a key role in the initial and rate-limiting step of de novo sphingolipid biosynthesis, and inhibiting SPT activity prevents the proliferation of certain cancer cells. Here, we identified a novel and orally available SPT inhibitor, compound-2. Compound-2 showed an anti-proliferative effect in several cancer cell models, reducing the levels of the sphingolipids ceramide and sphingomyelin. In the presence of compound-2, exogenously added S1P partially compensated the intracellular sphingolipid levels through the salvage pathway by partially rescuing compound-2-induced cytotoxicity. This suggested that the mechanism underlying the anti-proliferative effect of compound-2 involved the reduction of sphingolipid levels. Indeed, compound-2 promoted multinuclear formation with reduced endogenous sphingomyelin levels specifically in a compound-2-sensitive cell line, indicating that the effect was induced by sphingolipid reduction. Furthermore, compound-2 showed potent antitumor activity without causing significant body weight loss in the PL-21 acute myeloid leukemia mouse xenograft model. Therefore, SPT may be an attractive therapeutic anti-cancer drug target for which compound-2 may be a promising new drug. - Highlights: • We discovered compound-2, a novel and orally available SPT inhibitor. • Compound-2 was cytotoxic against PL-21 acute myeloid leukemia cells. • Compound-2 showed antitumor activity in the PL-21 mouse xenograft model.
[en] Hepatocyte growth factor/scatter factor (HGF/SF) plays critical roles in cancer progression through its specific receptor, MET. HGF/SF is usually synthesized and secreted as an inactive proform (pro-HGF/SF) by stromal cells, such as fibroblasts. Several serine proteases are reported to convert pro-HGF/SF to mature HGF/SF and among these, HGF activator (HGFA) and matriptase are the most potent activators. Increased activities of both proteases have been observed in various cancers. HGFA is synthesized mainly by the liver and secreted as an inactive pro-form. In cancer tissues, pro-HGFA is likely activated by thrombin and/or human kallikrein 1-related peptidase (KLK)-4 and KLK-5. Matriptase is a type II transmembrane serine protease that is expressed by most epithelial cells and is also synthesized as an inactive zymogen. Matriptase activation is likely to be mediated by autoactivation or by other trypsin-like proteases. Recent studies revealed that matriptase autoactivation is promoted by an acidic environment. Given the mildly acidic extracellular environment of solid tumors, matriptase activation may, thus, be accelerated in the tumor microenvironment. HGFA and matriptase activities are regulated by HGFA inhibitor (HAI)-1 (HAI-1) and/or HAI-2 in the pericellular microenvironment. HAIs may have an important role in cancer cell biology by regulating HGF/SF-activating proteases
[en] Since the finding that HIV recruits cellular ESCRT (endosomal sorting complexes required for transport) machinery to accomplish viral budding, this strategy has emerged as an escape route for enveloped viruses also. The work aimed to explore the participation of the cellular protein Alix (a human protein that acts as an adapter in the ESCRT pathway) on the transcription, protein expression, assembly and release of Dengue virus (DENV), and explore for its potential interaction with the viral protein NS3. To this purpose, A549 cells were infected with DENV2 and treated with small interfering RNAs (siRNA) to generate an Alix stable knockdown cells line. Also, an A549 cells line expressing a histidine-tagged NS3 protein was obtained. Both cells lines were used in immunoprecipitation and pull-down assays to assess the interaction between NS3 and Alix. The results showed that Alix knockdown had no effect on viral transcription or viral protein expression but influenced the assembly and release of DENV2 negatively. Finally, pull-down assays revealed the interaction between NS3 and Alix. The finding of an Alix participation in the production of DENV2 and its interaction with NS3 provides a potential target for the design of control/inhibition strategies against DENV spread.
[en] A protein showing strong antiviral activity against Bombyx mori nucleopolyhedrovirus (BmNPV) was purified from the digestive juice of B. mori larvae. The molecular mass of this protein was 24 271 Da. Partial N-terminal amino acid sequence of the protein was determined and cDNA was cloned based on the amino acid sequence. A homology search of the deduced amino acid sequence of the cDNA showed 94% identity with B. mori serine protease so the protein was designated B. mori serine protease-2 (BmSP-2). Analysis of BmSP-2 gene expression showed that this gene is expressed in the midgut but not in other tissues. In addition, BmSP-2 gene was shown to not be expressed in the molting and wandering stages, indicating that the gene is hormonally regulated. Our results suggest that BmSP-2, an insect digestive enzyme, can be a potential antiviral factor against BmNPV at the initial site of viral infection
[en] Highlights: • The gas phase ΔHf of selenocysteine has been calculated. • The two divergent values for the gas phase ΔHf of diethyl selenide have been disentangled and a value assigned. • The lowest energy conformers for selenocysteine have been identified. - Abstract: The gas phase enthalpy of formation of the amino acid containing selenium, selenocysteine, has been calculated using G3 and G4 calculations, the values being (−347.7 and −345.2) kJ · mol−1, respectively. The enthalpies of formation of the counterpart amino acids containing oxygen and sulfur, serine and cysteine, have also been calculated. The enthalpies of formation of compounds H2Z, C2H5ZH and (C2H5)2Z (Z=O, S, Se) have been calculated and compared with their available experimental values. The agreement between calculated and experimental values gives us confidence in our calculated values for the gas phase enthalpy of formation of selenocysteine
[en] Raf-1 kinase inhibitor protein (RKIP) has been reported to negatively regulate signal kinases of major survival pathways. RKIP activity is modulated in part by phosphorylation on Serine 153 by protein kinase C, which leads to dissociation of RKIP from Raf-1. RKIP expression is low in many human cancers and represents an indicator of poor prognosis and/or induction of metastasis. The prognostic power has typically been based on total RKIP expression and has not considered the significance of phospho-RKIP. The present study examined the expression levels of both RKIP and phospho-RKIP in human lung cancer tissue microarray proteomics technology. Total RKIP and phospho-RKIP expression levels were similar in normal and cancerous tissues. phospho-RKIP levels slightly decreased in metastatic lesions. However, the expression levels of phospho-RKIP, in contrast to total RKIP, displayed significant predictive power for outcome with normal expression of phospho-RKIP predicting a more favorable survival compared to lower levels (P = 0.0118); this was even more pronounced in more senior individuals and in those with early stage lung cancer. This study examines for the first time, the expression profile of RKIP and phospho-RKIP in lung cancer. Significantly, we found that phospho-RKIP was a predictive indicator of survival