Inhibitory effect of novel S,N-bisphosphonates on some carcinoma cell lines, osteoarthritis, and chronic inflammation

Dihydropyrrole-3-thiones: one-pot synthesis from propargylamines, acyl chlorides and sodium sulfide

An efficient one-pot synthesis of 1,2,5-trisubstituted-1,2-dihydro-3H-pyrrole-3-thiones (up to 91% yield), representatives of essentially new heterocyclic systems, by the successive treatment of available propargylamines with acyl chlorides (PdCl2/CuI/Ph3P/Et3N, toluene, 40-45 °C, 3 h) and sodium sulfide (Na2S·9H2O, EtOH, 20-25 °C, 7 h) has been developed. The synthesis comprises the addition of sulfide anions to the formed aminoacetylenic ketones followed by dehydrative cyclization of the prototropically rearranged adducts.

Gold-catalyzed redox cycloisomerization/nucleophilic addition/reduction: direct access to 2-phosphoryl indolin-3-ones

An efficient gold(I)-catalyzed redox cycloisomerization/nucleophilic addition/reduction reaction of o-nitroalkynes with various H-phosphorus oxides is established. Through the intramolecular redox cyclization of o-nitroalkynes and subsequent intermolecular nucleophilic addition/reduction with no external reactant, a variety of arylphosphoryl and alkylphosphoryl indolin-3-ones with high functional-group compatibility are obtained in moderate to good yields. Mechanistic studies suggest that phosphorus nucleophiles mediate the cleavage of the N-O bond as a reductant.

Dearomative oxyphosphorylation of indoles enables facile access to 2,2-disubstituted indolin-3-ones

A highly efficient oxidative dearomatization of indoles with H-phosphorus oxides in the presence of TEMPO oxoammonium salt has been demonstrated. Through the intramolecular oxidative dearomatization of indoles and subsequent intermolecular nucleophilic addition with phosphorus nucleophile, a variety of structurally diverse arylphosphoryl and alkylphosphoryl indolin-3-ones were obtained in good yields with a broad substrate scope and high functional-group compatibility.

Extensive protein expression changes induced by pamidronate in RAW 264.7 cells as determined by IP-HPLC

Background

Bisphosphonate therapy has become a popular treatment for osteoporosis, Paget’s disease, multiple myeloma, osteogenesis imperfecta, myocardial infarction, and cancer despite its serious side effects. Bisphosphonate-induced molecular signaling changes in cells are still not clearly elucidated.

Methods

As bisphosphonates are primarily engulfed by macrophages, we treated RAW 264.7 cells (a murine macrophage cell line) with pamidronate and investigated global protein expressional changes in cells by immunoprecipitation high performance liquid chromatography (IP-HPLC) using 218 antisera.

Results

Pamidronate upregulated proliferation-activating proteins associated with p53/Rb/E2F and Wnt/β-catenin pathways, but downregulated the downstream of RAS signaling, pAKT1/2/3, ERK-1, and p-ERK-1, and subsequently suppressed cMyc/MAX/MAD network. However, in situ proliferation index of pamidronate-treated RAW264.7 cells was slightly increased by 3.2% vs. non-treated controls. Pamidronate-treated cells showed increase in the expressions of histone- and DNA methylation-related proteins but decrease of protein translation-related proteins. NFkB signaling was also suppressed as indicated by the down-regulations of p38 and p-p38 and the up-regulation of mTOR, while the protein expressions related to cellular protection, HSP-70, NRF2, JNK-1, and LC3 were upregulated. Consequently, pamidronate downregulated the protein expressions related to immediate inflammation,cellular differentiation, survival, angiogenesis, and osteoclastogenesis, but upregulated PARP-1 and FAS-mediated apoptosis proteins. These observations suggest pamidronate affects global protein expressions in RAW 264.7 cells by stimulating cellular proliferation, protection, and apoptosis but suppressing immediate inflammation, differentiation, osteoclastogenesis, and angiogenesis. Accordingly, pamidronate appears to affect macrophages in several ways eliciting not only its therapeutic effects but also atypical epigenetic modification, protein translation, RAS and NFkB signalings. Therefore, our observations suggest pamidronate-induced protein expressions are dynamic, and the affected proteins should be monitored by IP-HPLC to achieve the therapeutic goals during treatment.

Structural requirements for bisphosphonate binding on hydroxyapatite: NMR study of bisphosphonate partial esters

Eighteen different bisphosphonates, including four clinically used bisphosphonate acids and their phosphoesters, were studied to evaluate how the bisphosphonate structure affects binding to bone. Bisphosphonates with weak bone affinity, such as clodronate, could not bind to hydroxyapatite after the addition of one ester group. Medronate retained its ability to bind after the addition of one ester group, and hydroxy-bisphosphonates could bind even after the addition of two ester groups. Thus, several bisphosphonate esters are clearly bone binding compounds. The following conclusions about bisphosphonate binding emerge: (1) a hydroxyl group in the geminal carbon takes part in the binding process and increases the bisphosphonate's ability to bind to bone; (2) the bisphosphonate's ability to bind decreases when the amount of ester groups increases; and (3) the location of the ester groups affects the bisphosphonate's binding ability.

Low toxicity and unprecedented anti-osteoclast activity of a simple sulfur-containing gem-bisphosphonate: a comparative study

Bisphosphonates (BPs) are key drugs for the treatment of bone resorption diseases like osteoporosis, Paget's disease and some forms of tumors. Recent findings underlined the importance of lipophilic N-containing BPs to ensure high biological activity. Herein we present some unprecedented results concerning the low toxicity and good anti-osteoclast activity of low molecular weight hydrophilic S-containing BPs. A series of S and N-containing BPs bearing aromatic and aliphatic substitution were prepared through Michael addition reaction between vinylidenebisphosphonate tetraethyl ester and the proper nucleophile under basic catalysis. S-containing BPs showed a generally low toxicity, determined with the neutral-red assay using the L929 cell line, and, in particular for an aliphatic one, a good biological activity assessed on primary cultures of human osteoclasts.

Design of new arylamino-2-ethane-1,1-diyl- and benzoxazole-2-methylene-bisphosphonates vs cytotoxicity and chronic inflammation diseases. From hydrophobicity prediction to synthesis and biological evaluation

A general synthetic approach to two new series of methylenebisphosphonates: arylamino-2-ethane-1,1-diyl- and benzoxazole-2-methylenebisphosphonates is presented. Acid hydrolysis of selected BPs was undertaken to give the corresponding bisphosphonic acid (BP-acid). Next, the prediction of the permeability (hydrophobicity) of the target compounds was measured, by a combination of RP-HPLC and computational techniques, to study the capacity of transporting the molecule through cellular membranes. Cytotoxicity/growth inhibition of 50% (GI(50), mg/L) and antichronic inflammation properties of the products were evaluated. Later on, a comparison of the pharmacological results with water-octanol partition coefficients (log K(OW)) of the compounds was also reported.