Performance of cementitious systems containing calcined clay in a chloride-rich environment: a review by TC-282 CCL.

In this review by TC- 282 CCL, a comprehensive examination of various facets of chloride ingress in calcined clay-based concrete in aggressive chloride-rich environments is presented due to its significance in making reinforced concrete structures susceptible to chloride-induced corrosion damages. The review presents a summary of available literature focusing on materials characteristics influencing the chloride resistance of calcined clay-based concrete, such as different clay purity, kaolinite content and other clay minerals, underscoring the significance of pore refinement, pore solution composition, and chloride binding mechanisms. Further, the studies dealing with the performance at the concrete scale, with a particular emphasis on transport properties, curing methods, and mix design, are highlighted. Benchmarking calcined clay mixes with fly ash or slag-based concrete mixes that are widely used in aggressive chloride conditions instead of OPC is recommended. Such comparison could extend the usage of calcined clay as a performance-enhancing mineral admixture in the form of calcined clay or LC2 (limestone-calcined clay). The chloride diffusion coefficient in calcined clay concrete is reported to be significantly lower (about 5-10 times in most literature available so far) compared to OPC, and even lower compared to fly ash and slag-based concrete at early curing ages reported across recent literature made with different types of cements and concrete mixes. Limited studies dealing with reinforcement corrosion point out that calcined clay delays corrosion initiation and reduces corrosion rates despite the reduction in critical chloride threshold. Most of these results on corrosion performance are mainly from laboratory studies and warrant field evaluation in future. Finally, two case studies demonstrating the application of calcined clay-based concrete in real-world marine exposure conditions are discussed to showcase the promising potential of employing low-purity calcined clay-based concrete for reducing carbon footprint and improving durability performance in chloride exposure.

Stabilization of c-KIT G-Quadruplex DNA Structures by the RNA Polymerase I Inhibitors BMH-21 and BA-41.

The stabilization of G-quadruplex DNA structures by small molecules with affinity to oncogene promoters has emerged as a promising anticancer strategy, due to a potential role in gene expression regulation. We explored the ability of BMH-21 (1) and its analogue BA-41 (2) to bind the G-quadruplex structure present in the c-KIT promoter by biophysical methods and molecular modeling. We provide evidence that both compounds interact with the c-KIT 21-mer sequence. The stable monomeric intramolecular parallel G-quadruplex obtained by the mutation of positions 12 and 21 allowed the precise determination of the binding mode by NMR and molecular dynamics studies. Both compounds form a complex characterized by one ligand molecule positioned over the tetrad at the 3'-end, stabilized by an extensive network of π-π interactions. The binding constants (Kb) obtained with fluorescence are similar for both complexes (around 106 M-1). Compound BA-41 (2) showed significant antiproliferative activity against a human lymphoma cell line, SU-DHL4, known to express substantial levels of c-KIT. However, the partial inhibition of c-KIT expression by Western blot analysis suggested that the interaction of compound 2 with the c-KIT promoter is not the primary event and that multiple effects provide a contribution as determinants of biological activity.

c-MYC G-quadruplex binding by the RNA polymerase I inhibitor BMH-21 and analogues revealed by a combined NMR and biochemical Approach.

BACKGROUND: Pyridoquinazolinecarboxamides have been reported as RNA polymerase I inhibitors and represent a novel class of potential antitumor agents. BMH-21, was reported to intercalate with GC-rich rDNA, resulting in nucleolar stress as a primary mechanism of cytotoxicity. METHODS: The interaction of BMH-21 and analogues with DNA G-quadruplex structures was studied by NMR and molecular modelling. The cellular response was investigated in a panel of human tumor cell lines and protein expression was examined by Western Blot analysis. RESULTS AND CONCLUSIONS: We explored the ability of BMH-21 and its analogue 2 to bind to G-quadruplex present in the c-MYC promoter, by NMR and molecular modelling studies. We provide evidence that both compounds are not typical DNA intercalators but are effective binders of the tested G-quadruplex. The interaction with c-MYC G-quadruplex was reflected in down-regulation of c-Myc expression in human tumor cells. The inhibitory effect was almost complete in lymphoma cells SUDHL4 characterized by overexpression of c-Myc protein. This downregulation reflected an early and persistent modulation of cMyc mRNA. Given the relevance of c-MYC in regulation of ribosome biogenesis, it is conceivable that the inhibition of c-MYC contributes to the perturbation of nuclear functions and RNA polymerase I activity. Similar experiments with CX-5461, another RNA polymerase I transcription inhibitor, indicate the same behaviour in G-quadruplex stabilization. GENERAL SIGNIFICANCE: Our results support the hypothesis that BMH-21 and analogue compounds share the same mechanism, i.e. G-quadruplex binding as a primary event of a cascade leading to inhibition of RNA polymerase I and apoptosis.

Synthesis and Evaluation of New Naphthalene and Naphthoquinone Derivatives as Anticancer Agents.

DNA topoisomerase I inhibitors, both synthetic and of natural origin, are receiving increasing consideration primarily as drugs against refractory tumors. Alkannin and shikonin, two enantiomeric dyes from Alkanna tinctoria and Lithospermum erythrorhizon, have been known over many centuries as dyestuff, wound healing, anti-inflammatory, antibacterial and antitumor substances. Although multiple mechanisms appear to be implicated, their potency is associated with the inhibition of topoisomerase I and with the redox properties of the naphthazarin scaffold. Here, the synthesis of new naphthalene and naphthoquinone derivatives inspired by alkannin and shikonin is described and their structural and biological properties were examined. Different oxidation states of the naphthalene nucleus were examined to observe the effect of this parameter on cytotoxicity. Antiproliferative activities against a panel of human cancer cell lines were evaluated and the implication of topoisomerase I was assessed.

Low-Temperature Curing Strength Enhancement in Cement-Based Materials Containing Limestone Powder.

With the ongoing sustainability movement, the incorporation of limestone powder in cementitious binders for concrete in the U.S. has become a subject of renewed interest. In addition to accelerating the early age hydration reactions of cementitious systems by providing additional surfaces for nucleation and growth of products, limestone powder is also intriguing based on its influence on low-temperature curing. For example, previous results have indicated that the utilization of limestone powder to replace one quarter of the fly ash in a high volume fly ash mixture (40 % to 60 % cement replacement) produces a reduction in the apparent activation energy for setting for temperatures below 25 °C. In the present study, the relationship between heat release and compressive strength of mortars at batching/curing temperatures of 10 °C and 23 °C is investigated. For Portland-limestone cements (PLC) with limestone additions on the order of 10 %, a higher strength per unit heat release is obtained after only 7 d of curing in lime water. Surprisingly, in some cases, the absolute strength of these mortar cubes measured at 7 d is higher when cured at 10 °C than at 23 °C. Solubilities vs. temperature, reaction stoichiometries and enthalpies, and projected phase distributions based on thermodynamic modeling for the cementitious phases are examined to provide some theoretical insight into this strength enhancement. For a subset of the investigated cements, thermogravimetric analysis (TGA), quantitative X-ray diffraction (XRD), and scanning electron microscopy (SEM) are conducted on 7-d paste specimens produced at the two temperatures to examine differences in their reaction rates and the phases produced. The strength enhancement observed in the PLC cements is related to the cement hydration products formed in the presence of carbonates as a function of temperature.

Investigation on the ZBG-functionality of phenyl-4-yl-acrylohydroxamic acid derivatives as histone deacetylase inhibitors.

A series of alternative Zn-binding groups were explored in the design of phenyl-4-yl-acrylohydroxamic acid derivatives as histone deacetylase (HDAC) inhibitors. Most of the synthesized compounds were less effective than the parent hydroxamic acid. However, the profile of activity shown by the analog bearing a hydroxyurea head group, makes this derivative promising for further investigation.

New macrocyclic analogs of the natural histone deacetylase inhibitor FK228; design, synthesis and preliminary biological evaluation.

Among the natural histone deacetylase inhibitors (HDACi), the bicyclic depsipeptide macrolactone FK228 stands out for its unique chemical structure and mechanism of action. In order to expand the chemical diversity, exploiting the FK228 peculiar structure, we have synthesized a collection of 24 simplified novel analogs. A first series consists of bicyclic macrolactones, where the carboxy terminus of the natural compound was substituted by peptidomimetic aminomethylphenylacetic acid derivatives. These analogs, 7a-i, showed submicromolar cytotoxic activity, even though very low inhibitory activity against HDAC enzymes, suggesting that most probably they behave with a mechanism different from the natural compound. One of the most active members in the group, 7g, was evaluated in vivo and exhibited significant antitumor activity. This evidence supports that the activity is unrelated to HDAC inhibition and these compounds represent a novel series of promising active agents. Another analog series consists of monocyclic macrolactones, 9a-c and 10a-d which lack the disulfide bridge and bear the protected sulfur on the linear external chain; they showed similar cytotoxic activities compared to the natural compound, but proved to be very sensitive to the nature of the sulfur protection. In fact, when the sulfur was protected by an 1-octanoyl residue, like in 9b, the product displayed a one digit nanomolar activity. The results provide evidence that our approach may be followed to develop novel series of FK228 analogs.

Pleiotropic antitumor effects of the pan-HDAC inhibitor ITF2357 against c-Myc-overexpressing human B-cell non-Hodgkin lymphomas.

Histone deacetylases (HDAC) extensively contribute to the c-Myc oncogenic program, pointing to their inhibition as an effective strategy against c-Myc-overexpressing cancers. We, thus, studied the therapeutic activity of the new-generation pan-HDAC inhibitor ITF2357 (Givinostat®) against c-Myc-overexpressing human B-cell non-Hodgkin lymphomas (B-NHLs). ITF2357 anti-proliferative and pro-apoptotic effects were analyzed in B-NHL cell lines with c-Myc translocations (Namalwa, Raji and DOHH-2), stabilizing mutations (Raji) or post-transcriptional alterations (SU-DHL-4) in relationship to c-Myc modulation. ITF2357 significantly delayed the in vitro growth of all B-NHL cell lines by inducing G1 cell-cycle arrest, eventually followed by cell death. These events correlated with the extent of c-Myc protein, but not mRNA, downregulation, indicating the involvement of post-transcriptional mechanisms. Accordingly, c-Myc-targeting microRNAs let-7a and miR-26a were induced in all treated lymphomas and the cap-dependent translation machinery components 4E-BP1, eIF4E and eIF4G, as well as their upstream regulators, Akt and PIM kinases, were inhibited in function of the cell sensitivity to ITF2357, and, in turn, c-Myc downregulation. In vivo, ITF2357 significantly hampered the growth of Namalwa and Raji xenografts in immunodeficient mice. Noteworthy, its combination with suboptimal cyclophosphamide, achieved complete remissions in most animals and equaled or even exceeded the activity of optimal cyclophosphamide. Collectively, our findings provide the rationale for testing the clinical advantages of adding ITF2357 to current therapies for the still very ominous c-Myc-overexpressing lymphomas. They equally provide the proof-of-concept for its clinical evaluation in rational combination with the promising inhibitors of B-cell receptor and PI3K/Akt/mTOR axis currently in the process of development.

7-Azaindole-1-carboxamides as a new class of PARP-1 inhibitors.

7-Azaindole-1-carboxamides were designed as a new class of PARP-1 inhibitors. The compounds displayed a variable pattern of target inhibition profile that, in part, paralleled the antiproliferative activity in cell lines characterized by homologous recombination defects. A selected compound (1l; ST7710AA1) showed significant in vitro target inhibition and capability to substantially bypass the multidrug resistance mediated by Pgp. In antitumor activity studies against the MX1 human breast carcinoma growth in nude mice, the compound exhibited an effect similar to that of Olaparib in terms of tumor volume inhibition when used at a lower dose than the reference compound. Treatment was well tolerated, as no deaths or significant weight losses were observed among the treated animals.

Quinazolinecarboline alkaloid evodiamine as scaffold for targeting topoisomerase I and sirtuins.

This paper reports the synthesis of a series of evodiamine derivatives. We assayed the ability to inhibit cell growth on three human tumour cell lines (H460, MCF-7 and HepG2) and we evaluated the capacity to interfere with the catalytic activity of topoisomerase I both by the relaxation assay and the occurrence of the cleavable complex. Moreover, whose effect on sirtuins 1, 2 and 3 was investigated. Finally, molecular docking analyses were performed in an attempt to rationalize the biological results.

Design, synthesis, and biological evaluation of novel cRGD-paclitaxel conjugates for integrin-assisted drug delivery.

The efficacy of taxane-based antitumor therapy is limited by several drawbacks which result in a poor therapeutic index. Thus, the development of approaches that favor selective delivery of taxane drugs (e.g., paclitaxel, PTX) to the disease area represents a truly challenging goal. On the basis of the strategic role of integrins in tumor cell survival and tumor progression, as well as on integrin expression in tumors, novel molecular conjugates were prepared where PTX is covalently attached to either cyclic AbaRGD (Azabicycloalkane-RGD) or AmproRGD (Aminoproline-RGD) integrin-recognizing matrices via structurally diverse connections. Receptor-binding assays indicated satisfactory-to-excellent α(V)ß(3) binding capabilities for most conjugates, while in vitro growth inhibition assays on a panel of human tumor cell lines revealed outstanding cell sensitivity values. Among the nine conjugate ensemble, derivative 21, bearing a robust triazole ring connected to ethylene glycol units by an amide function and showing excellent cell sensitivity properties, was selected for in vivo studies in an ovarian carcinoma model xenografted in immunodeficient mice. Remarkable antitumor activity was attained, superior to that of PTX itself, which was associated with a marked induction of aberrant mitoses, consistent with the mechanism of action of spindle poisons. Overall, the novel cRGD-PTX conjugates disclosed here represent promising candidates for further advancement in the domain of targeted antitumor therapy.

Sulfonates-PMMA nanoparticles conjugates: a versatile system for multimodal application.

We report herein the viability of a novel nanoparticles (NPs) conjugated system, namely the attachment, based on ionic and hydrophobic interactions, of different sulfonated organic salts to positively charged poly(methylmethacrylate) (PMMA)-based core-shell nanoparticles (EA0) having an high density of ammonium groups on their shells. In this context three different applications of the sulfonates@EA0 systems have been described. In detail, their ability as cytotoxic drugs and pro-drugs carriers was evaluated in vitro on NCI-H460 cell line and in vivo against human ovarian carcinoma IGROV-1 cells. Besides, 8-hydroxypyrene-1,3,6-trisulfonic acid, trisodium salt (HPTS) was chosen for NPs loading, and its internalization as bioimaging probe was evaluated on Hep G2 cells. Overall, the available data support the interest for these PMMA NPs@sulfonates systems as a promising formulation for theranostic applications. In vivo biological data strongly support the potential value of these core-shell NPs as delivery system for negatively charged drugs or biologically active molecules. Additionally, we have demonstrated the ability of these PMMA core-shell nanoparticles to act as efficient carriers of fluorophores. In principle, thanks to the high PMMA NPs external charge density, sequential and very easy post-loading of different sulfonates is achievable, thus allowing the preparation of nanocarriers either with bi-modal drug delivery behaviour or as theranostic systems.

Magnetic tweezers measurements of the nanomechanical properties of DNA in the presence of drugs.

Herein, we study the nanomechanical characteristics of single DNA molecules in the presence of DNA binders, including intercalating agents (ethidium bromide and doxorubicin), a minor groove binder (netropsin) and a typical alkylating damaging agent (cisplatin). We have used magnetic tweezers manipulation techniques, which allow us to measure the contour and persistence lengths together with the bending and torsional properties of DNA. For each drug, the specific variations of the nanomechanical properties induced in the DNA have been compared. We observed that the presence of drugs causes a specific variation in the DNA extension, a shift in the natural twist and a modification of bending dependence on the imposed twist. By introducing a naive model, we have justified an anomalous correlation of torsion data observed in the presence of intercalators. Finally, a data analysis criterion for discriminating between different molecular interactions among DNA and drugs has been suggested.

Proteomic analysis of cellular response to novel proapoptotic agents related to atypical retinoids in human IGROV-1 ovarian carcinoma cells.

Novel agents characterized by the scaffold of the atypical retinoid ST1926, but containing different chemical functions (carboxylic or hydroxamic acid), exhibit potent proapoptotic activity. In the present paper, we show that the treatment of the IGROV-1 ovarian cancer cell line with compounds sharing structural features with ST1926 (ST1898, ST3595, ST3056) determines a strong inhibition of proliferation mainly due to apoptotic cell death. In an effort to understand the mechanism of action of these compounds, we performed a proteomics analysis of IGROV-1 total lysates and nuclear extracts. Using this approach, we found that deregulation of calcium homeostasis, oxidative stress, cytoskeleton reorganization, and deregulation of proteasome function may represent important pathways involved in response of IGROV-1 cells to the studied compounds. The most prominent effect was down-regulation of factors involved in protein degradation, an event more marked in cells treated with ST3595. In addition, we identified proteins specifically modulated by each treatment, including prohibitin and cochaperone P23 (ST1898), pre-mRNA splicing factor SF2p32 and clathrin light chain (ST3595), as well as Far upstream element (FUSE) binding protein 1 and DNA-binding protein B (ST3056). By identifying proteins modulated by novel proapoptotic agents, this study provides insights into critical aspects of their mechanism of action.

Pre-clinical and clinical significance of heparanase in Ewing's sarcoma.

Heparanase is an endoglycosidase that specifically cleaves heparan sulphate side chains of heparan sulphate proteoglycans, activity that is strongly implicated in cell migration and invasion associated with tumour metastasis, angiogenesis and inflammation. Heparanase up-regulation was documented in an increasing number of human carcinomas, correlating with reduced post-operative survival rate and enhanced tumour angiogenesis. Expression and significance of heparanase in human sarcomas has not been so far reported. Here, we applied the Ewing's sarcoma cell line TC71 and demonstrated a potent inhibition of cell invasion in vitro and tumour xenograft growth in vivo upon treatment with a specific inhibitor of heparanase enzymatic activity (compound SST0001, non-anticoagulant N-acetylated, glycol split heparin). Next, we examined heparanase expression and cellular localization by immunostaining of a cohort of 69 patients diagnosed with Ewing's sarcoma. Heparanase staining was noted in all patients. Notably, heparanase staining intensity correlated with increased tumour size (P = 0.04) and with patients' age (P = 0.03), two prognostic factors associated with a worse outcome. Our study indicates that heparanase expression is induced in Ewing's sarcoma and associates with poor prognosis. Moreover, it encourages the inclusion of heparanase inhibitors (i.e. SST0001) in newly developed therapeutic modalities directed against Ewing's sarcoma and likely other malignancies.

Atomic force microscopy study of DNA conformation in the presence of drugs.

Binding of ligands to DNA gives rise to several relevant biological and biomedical effects. Here, through the use of atomic force microscopy (AFM), we studied the consequences of drug binding on the morphology of single DNA molecules. In particular, we quantitatively analyzed the effects of three different DNA-binding molecules (doxorubicin, ethidium bromide, and netropsin) that exert various pharmacologic and therapeutic effects. The results of this study show the consequences of intercalation and groove molecular binding on DNA conformation. These single-molecule measurements demonstrate morphological features that reflect the specific modes of drug-DNA interaction. This experimental approach may have implications in the design of therapeutically effective agents.

Synthesis and biological evaluation of imidazolo[2,1-b]benzothiazole derivatives, as potential p53 inhibitors.

Since activation of p53 in response to cytotoxic stress may have proapoptotic or protective effects depending on the nature of the injury, inhibitors of p53 may have therapeutic interest as modulators of chemotherapy toxicity or efficacy. In an attempt to identify novel p53 inhibitors, a quality collection of compounds structurally related to pifithrin-ß were designed and synthesized as potential inhibitors of p53. The biochemical and biological evaluations supported that compounds of the tetrahydrobenzothiazole series were inhibitors of the p53 transcriptional activity and were effective in enhancing paclitaxel-induced apoptosis. In contrast, in spite of the increased cytotoxic potency, selected compounds of the benzothiazole series were not able to modulate the transcriptional activity of p53, as indicated by lack of change of p21 expression. The therapeutic interest of the compounds of the former series in combination with taxanes was confirmed in a human tumor xenograft model.

Synthesis, structural, and biological evaluation of bis-heteroarylmaleimides and bis-heterofused imides.

Bis-2,3-heteroarylmaleimides and polyheterocondensed imides joined through nitrogen atoms of the N,N'-bis(ethyl)-1,3-propanediamine linker were prepared from substituted maleic anhydrides and symmetrical diamines in good to satisfactory yields and short reaction times using microwave heating. The novel molecules were shown to inhibit proliferation of human tumor cells (NCI-H460 lung carcinoma) and rat aortic smooth muscle cells (SMCs) with variable potencies. Compound 11a, the most potent one of the series, showed IC(50) values comparable to those observed for the leading molecule elinafide in both cell lines, but with a higher selectivity toward human tumor cells. Compound 11a affected G1/S phase transition of the cell cycle, showed in vitro DNA intercalating activity and in vivo antitumor activity. A thorough structural analysis of the 11a-DNA complex was also made by mean of NMR and computational techniques.

The enhancement of antiproliferative and proapoptotic activity of HDAC inhibitors by curcumin is mediated by Hsp90 inhibition.

Curcumin, a natural polyphenol, has been described to exhibit effects on signaling pathways, leading to induction of apoptosis. In this study, we observed that curcumin inhibited Hsp90 activity causing depletion of client proteins implicated in survival pathways. Based on this observation, this study was designed to investigate the cellular effects of curcumin combination with the pan-HDAC inhibitors, vorinostat and panobinostat, which induce hyperacetylation of Hsp90, resulting in inhibition of its chaperone function. The results showed that, at subtoxic concentrations, curcumin markedly sensitized tumor cells to vorinostat- and panobinostat-induced growth inhibition and apoptosis. The sensitization was associated with persistent depletion of Hsp90 client proteins (EGFR, Raf-1, Akt, and survivin). In conclusion, our findings document a novel mechanism of action of curcumin and support the therapeutic potential of curcumin/HDAC inhibitors combination, because the synergistic interaction was observed at pharmacologically achievable concentrations, which were ineffective when each drug was used alone.