Pre-clinical characterization of CX-4945, a potent and selective small molecule inhibitor of CK2 for the treatment of cancer

In this article we describe the preclinical characterization of 5-(3-chlorophenylamino) benzo[c][2,6]naphthyridine-8-carboxylic acid (CX-4945), the first orally available small molecule inhibitor of protein CK2 in clinical trials for cancer. CX-4945 was optimized as an ATP-competitive inhibitor of the CK2 holoenzyme (Ki = 0.38 nM). Iterative synthesis and screening of analogs, guided by molecular modeling, led to the discovery of orally available CX-4945. CK2 promotes signaling in the Akt pathway and CX-4945 suppresses the phosphorylation of Akt as well as other key downstream mediators of the pathway such as p21. CX-4945 induced apoptosis and caused cell cycle arrest in cancer cells in vitro. CX-4945 exhibited a dose-dependent antitumor activity in a xenograft model of PC3 prostate cancer model and was well tolerated. In vivo time-dependent reduction in the phosphorylation of the biomarker p21 at T145 was observed by immunohistochemistry. Inhibition of the newly validated CK2 target by CX-4945 represents a fresh therapeutic strategy for cancer.     

Y-chromosomal variation in sub-Saharan Africa: insights into the history of Niger-Congo groups

Technological and cultural innovations as well as climate changes are thought to have influenced the diffusion of major language phyla in sub-Saharan Africa. The most widespread and the richest in diversity is the Niger-Congo phylum, thought to have originated in West Africa ～ 10,000 years ago (ya). The expansion of Bantu languages (a family within the Niger-Congo phylum) ～ 5,000 ya represents a major event in the past demography of the continent. Many previous studies on Y chromosomal variation in Africa associated the Bantu expansion with haplogroup E1b1a (and sometimes its sublineage E1b1a7). However, the distribution of these two lineages extends far beyond the area occupied nowadays by Bantu-speaking people, raising questions on the actual genetic structure behind this expansion. To address these issues, we directly genotyped 31 biallelic markers and 12 microsatellites on the Y chromosome in 1,195 individuals of African ancestry focusing on areas that were previously poorly characterized (Botswana, Burkina Faso, Democratic Republic of Congo, and Zambia). With the inclusion of published data, we analyzed 2,736 individuals from 26 groups representing all linguistic phyla and covering a large portion of sub-Saharan Africa. Within the Niger-Congo phylum, we ascertain for the first time differences in haplogroup composition between Bantu and non-Bantu groups via two markers (U174 and U175) on the background of haplogroup E1b1a (and E1b1a7), which were directly genotyped in our samples and for which genotypes were inferred from published data using linear discriminant analysis on short tandem repeat (STR) haplotypes. No reduction in STR diversity levels was found across the Bantu groups, suggesting the absence of serial founder effects. In addition, the homogeneity of haplogroup composition and pattern of haplotype sharing between Western and Eastern Bantu groups suggests that their expansion throughout sub-Saharan Africa reflects a rapid spread followed by backward and forward migrations. Overall, we found that linguistic affiliations played a notable role in shaping sub-Saharan African Y chromosomal diversity, although the impact of geography is clearly discernible.     

Effects of taxon sampling and tree reconstruction methods on phylodiversity metrics

相似文献   

Temperature effects on the hydrodynamic radius of the intrinsically disordered N‐terminal region of the p53 protein

Intrinsically disordered proteins (IDPs) are often characterized in terms of the hydrodynamic radius, R_h. The R_h of IDPs are known to depend on fractional proline content and net charge, where increased numbers of proline residues and increased net charge cause larger R_h. Though sequence and charge effects on the R_h of IDPs have been studied, the temperature sensitivity has been noted only briefly. Reported here are R_h measurements in the temperature range of 5–75°C for the intrinsically disordered N‐terminal region of the p53 protein, p53(1–93). Of note, the R_h of this protein fragment was highly sensitive to temperature, decreasing from 35 Å at 5°C to 26 Å at 75°C. Computer generated simulations of conformationally dynamic and disordered polypeptide chains were performed to provide a hypothesis for the heat‐induced compaction of p53(1–93) structure, which was opposite to the heat‐induced increase in R_h observed for a model folded protein. The simulations demonstrated that heat caused R_h to trend toward statistical coil values for both proteins, indicating that the effects of heat on p53(1–93) structure could be interpreted as thermal denaturation. The simulation data also predicted that proline content contributed minimally to the native R_h of p53(1–93), which was confirmed by measuring R_h for a substitution variant that had all 22 proline residues changed for glycine. Proteins 2014; 82:668–678. © 2013 Wiley Periodicals, Inc.     

Biochemical and mass spectrometric characterization of human N-acylethanolamine-hydrolyzing Acid amidase inhibition

The mechanism of inactivation of human enzyme N-acylethanolamine-hydrolyzing acid amidase (hNAAA), with selected inhibitors identified in a novel fluorescent based assay developed for characterization of both reversible and irreversible inhibitors, was investigated kinetically and using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). 1-Isothiocyanatopentadecane (AM9023) was found to be a potent, selective and reversible hNAAA inhibitor, while two others, 5-((biphenyl-4-yl)methyl)-N,N-dimethyl-2H-tetrazole-2-carboxamide (AM6701) and N-Benzyloxycarbonyl-L-serine β-lactone (N-Cbz-serine β-lactone), inhibited hNAAA in a covalent and irreversible manner. MS analysis of the hNAAA/covalent inhibitor complexes identified modification only of the N-terminal cysteine (Cys126) of the β-subunit, confirming a suggested mechanism of hNAAA inactivation by the β-lactone containing inhibitors. These experiments provide direct evidence of the key role of Cys126 in hNAAA inactivation by different classes of covalent inhibitors, confirming the essential role of cysteine for catalysis and inhibition in this cysteine N-terminal nucleophile hydrolase enzyme. They also provide a methodology for the rapid screening and characterization of large libraries of compounds as potential inhibitors of NAAA, and subsequent characterization or their mechanism through MALDI-TOF MS based bottom up-proteomics.     

The influence of age on fecal steroid hormone levels in male Budongo Forest chimpanzees (Pan troglodytes schweinfurthii)

Potential interactions between age and endocrinological functioning have been understudied in wild ape populations. Therefore, we examined the relationship between age and the secretion of androgens and glucocorticoids in 15 juvenile, subadult, and adult male chimpanzees (Pan troglodytes schweinfurthii) free ranging in the Budongo Forest of Uganda. One hundred and nine fecal samples were opportunistically collected, between 07:30 and 13:30 hr, during the wet season. Fecal samples were preserved, by oven drying, and steroid content extracted before radioimmunoassay for dehydroepiandrosterone-sulfate (DHEA-S), testosterone (TEST), cortisol (CORT), and corticosterone (CCT). Employing indexes of age as predictive factors, linear mixed-effects modeling and non-parametric statistical comparisons of fecal steroid levels were conducted. Age was observed to significantly influence the production of both glucocorticoids and androgens in male Budongo Forest chimpanzees. Basically, whereas TEST and CORT increased, DHEA-S and CCT levels slightly declined as animals matured.