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This study aimed at the development of improved drugs against human osteosarcoma, which is the most common primary bone tumor in children and teenagers with a low prognosis. New insights into the impact of an unconventional Pd(II) anticancer agent on human osteosarcoma cells were obtained by synchrotron radiation-Fourier transform infrared microspectroscopy and quasi-elastic neutron scattering (QENS) experiments from its effect on the cellular metabolism to its influence on intracellular water, which can be regarded as a potential secondary pharmacological target. Specific infrared biomarkers of drug action were identified, enabling a molecular-level description of variations in cellular biochemistry upon drug exposure. The main changes were detected in the protein and lipid cellular components, namely, in the ratio of unsaturated-to-saturated fatty acids. QENS revealed reduced water mobility within the cytoplasm for drug-treated cells, coupled to a disruption of the hydration layers of biomolecules. Additionally, the chemical and dynamical profiles of osteosarcoma cells were compared to those of metastatic breast cancer cells, revealing distinct dissimilarities that may influence drug activity.

Cisplatin (cDDP) resistance is a matter of concern in triple-negative breast cancer therapeutics. We measured the metabolic response of cDDP-sensitive (S) and -resistant (R) MDA-MB-231 cells to Pd2Spermine(Spm) (a possible alternative to cDDP) compared to cDDP to investigate (i) intrinsic response/resistance mechanisms and (ii) the potential cytotoxic role of Pd2Spm. Cell extracts were analyzed by untargeted nuclear magnetic resonance metabolomics, and cell media were analyzed for particular metabolites. CDDP-exposed S cells experienced enhanced antioxidant protection and small deviations in the tricarboxylic acid cycle (TCA), pyrimidine metabolism, and lipid oxidation (proposed cytotoxicity signature). R cells responded more strongly to cDDP, suggesting a resistance signature of activated TCA cycle, altered AMP/ADP/ATP and adenine/uracil fingerprints, and phospholipid biosynthesis (without significant antioxidant protection). Pd2Spm impacted more markedly on R/S cell metabolisms, inducing similarities to cDDP/S cells (probably reflecting high cytotoxicity) and strong additional effects indicative of amino acid depletion, membrane degradation, energy/nucleotide adaptations, and a possible beneficial intracellular γ-aminobutyrate/glutathione-mediated antioxidant mechanism.

Photoacoustic calorimetry and luminescence techniqueswere used to measure singlet oxygen quantum yields (ΦΔ) of selected 5,10,15,20‐tetrakis(aryl)porphyrins and of the novel chlorin shown. The use of validated photoacoustic references removes some inconsistencies existing in the literature. Excitation of halogenated porphyrins produces high yields of long‐lived triplet states that efficiently transfer their energy to singlet oxygen. A route for red‐absorbing, efficient singlet‐oxygen photosensitisers is described.

We report the three-dimensional crystal structure of acidic seminal fluid protein (aSFP), a 12.9 kDa polypeptide of the spermadhesin family isolated from bovine seminal plasma, solved by the multiple isomorphous replacement method and refined with data to 1.9 A˚ resolution with a final R-factor of 17.3%. aSFP is built by a single CUB domain architecture, a 100 to 110 amino-acid-residue extracellular module found in 16 functionally diverse proteins. The structure of aSFP reveals that the CUB domain displays a β-sandwich topology organised into two 5-stranded β-sheets, each of which contain two parallel and four antiparallel strands. The structure of aSFP is almost identical to that of porcine spermadhesins PSP-I and PSP-II, which in turn show limited structural similarity with jellyroll topologies of certain virus capsid proteins. Essentially, topologically conserved residues in these proteins are those internal amino acids forming the hydrophobic core of the CUB and the jellyroll domains, suggesting their importance in maintaining the integrity of these protein folds. On the other hand, the structure of aSFP shows structural features that are unique to this protein and which may provide a structural ground for understanding the distinct biological properties of different members of the spermadhesin protein family.

We previously demonstrated that jarastatin (JT), a new disintegrin from Bothrops jararacavenom, altered actin dynamics in human polymorphonuclear neutrophils (PMNs) and inhibited cell migration in vivo and in vitro (14). In this study, we evaluated the effects of JT and two other monomeric disintegrins, kistrin (KR) and flavoridin (FL), on PMN chemotaxis and chemokinesis in vitro and on the activation of integrin‐mediated pathways. Although JT, but not KR or FL, was chemotactic, only KR was chemokinetic to PMN. However, preincubation of PMN with any disintegrins inhibited chemotaxis for fMLP. Treatment of PMN with JT and KR increased actin polymerization, whereas FL reduced the content of F‐actin. The effects of JT and KR on actin dynamics were inhibited (50%) by genistein, a tyrosine kinase inhibitor. Accordingly, JT and KR induced an increase in tyrosine phosphorylation, whereas FL had no effect. The three disintegrins were able to induce focal adhesion kinase activation. However, JT and KR promoted Erk‐2 nuclear translocation, and FL inhibited Erk‐2 activation. The data suggest that although the disintegrins JT and KR directly activate integrin‐coupled signaling, FL may interact differently with integrins, triggering an inhibitory pathway modulated by focal adhesion kinase activation.