Designed Compounds for Recognition of 10 Base Pairs of DNA with Two AT Binding Sites

Short AT base pair sequences that are separated by a small number of GCs are common in eukaryotic parasite genomes. Cell-permeable compounds that bind effectively and selectively to such sequences present an attractive therapeutic approach. Compounds with linked, one or two amidine-benzimidazole-phenyl (ABP) motifs were designed, synthesized, and evaluated for binding to adjacent AT sites by biosensor-surface plasmon resonance (SPR). A surprising feature of the linked ABP motifs is that a set of six similar compounds has three different minor groove binding modes with the target sequences. Compounds with one ABP bind independently to two separated AT sites. Unexpectedly, compounds with two ABP motifs can bind strongly either as monomers or as cooperative dimers to the full site. The results are supported by mass spectrometry and circular dichroism, and models to explain the different binding modes are presented

Decomposition rate of AmpB in lipid formulations.

<p>Data indicate mean rate of loss of AmB ± SD (n = 4). Results derived from the data in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0000913#pntd-0000913-g001" target="_blank">Fig. 1</a> and <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0000913#pntd-0000913-g002" target="_blank">2</a>.</p

Stability of AmB in lipid suspensions at 30°C over 60 days.

<p>Symbols: solid diamonds: iCo-010; solid squares: iCo-011; crosses: iCo-012; open circles: iCo-013. Data represent mean ± SD (n = 4).</p

Stability of AmB in lipid formulations in fasted-state simulated intestinal fluid (FaSSIF) at 37°C.

<p>Symbols: solid diamonds: iCo-010; solid squares: iCo-011; crosses: iCo-012; open circles: iCo-013.Data represent mean ± SD (n = 3).</p

Urea Derivatives of 2‑Aryl-benzothiazol-5-amines: A New Class of Potential Drugs for Human African Trypanosomiasis

A previous publication from this lab (Patrick, et al. Bioorg. Med. Chem. <b>2016</b>, 24, 2451–2465) explored the antitrypanosomal activities of novel derivatives of 2-(2-benzamido)­ethyl-4-phenylthiazole (<b>1</b>), which had been identified as a hit against Trypanosoma brucei, the causative agent of human African trypanosomiasis. While a number of these compounds, particularly the urea analogues, were quite potent, these molecules as a whole exhibited poor metabolic stability. The present work describes the synthesis of 65 new analogues arising from medicinal chemistry optimization at different sites on the molecule. The most promising compounds were the urea derivatives of 2-aryl-benzothiazol-5-amines. One such analogue, (<i>S</i>)-2-(3,4-difluorophenyl)-5-(3-fluoro-<i>N</i>-pyrrolidylamido)­benzothiazole (<b>57</b>) was chosen for in vivo efficacy studies based upon in vitro activity, metabolic stability, and brain penetration. This compound attained 5/5 cures in murine models of both early and late stage human African trypanosomiasis, representing a new lead for the development of drugs to combat this neglected disease

HPLC/UV chromatograms and concentration-time profiles of DB844/metabolites following incubation of DB844 with male vervet monkey liver microsomes.

<p>A: HPLC/UV chromatograms; B: Concentration-time profiles of DB844 and metabolites. Incubation mixtures (1 ml at pH7.4, in triplicate) contained 10 µM DB844 and 0.2 mg/ml monkey liver microsomes. Aliquots were taken at 0.2, 5, 15, 30, and 120 min and evaluated for concentrations of DB844 and six metabolites (M1A, M1B, M2A, M2B, M3, and DB820). Metabolites M4A and M4B were not quantified due to lack of synthetic standards.</p

Plasma concentration-time profiles following oral administration of the last (14^th) daily dose of DB844.

<p>Symbols and error bars represent geometric means and SEs, respectively, for DB844 (△) and DB820 (○). The monkeys (n = 7) were treated with DB844 at 6 mg/kg×14 days, from 28–41 days post infection. The insert graph shows the extended profile up to 28 days post the last daily dose of DB844.</p

Parasitaemia pattern in monkeys infected with <i>T.b. rhodesiense</i> KETRI 2537 and subsequently treated with DB844.

<p>Symbols and error bars represent means and SEs, respectively, of 7 animals; monkeys were treated with DB844 at 6 mg/kg×14 days, from 28–41 days post infection; Log parasitaemia values were determined by microscopic examination of wet smears of blood using the matching method of Herbert and Lumsden, 1976 <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0001734#pntd.0001734-Ndungu1" target="_blank">[23]</a>.</p

Changes in red cell distribution width in monkeys following infection and subsequent treatment with DB844.

<p>Symbols and error bars represent means and SEs, respectively, of seven monkeys that were treated with DB844 at 6 mg/kg×14 days, from 28–41 days post infection.</p

Transient infection and DB844 induced changes in clinical chemistry indicators of liver and kidney function.

<p>Symbols represent mean ± SE (n = 7) of aspartate aminotransferase (AST, ▪), alanine aminotransferase (ALT, □), total bilirubin (•), direct bilirubin (0), blood urea nitrogen (BUN, ▴) and albumin (◊); monkeys were treated with DB844 at 6 mg/kg×14 days, from 28–41 days post infection.</p