Protein ruthenation and DNA alkylation: chlorambucil-functionalized RAPTA complexes and their anticancer activity

Chemotherapeutics for the treatment of tumorigenic conditions that feature novel modes of action are highly sought after to overcome the limitations of current chemotherapies. Herein, we report the conjugation of the alkylating agent chlorambucil to the RAPTA scaffold, a well-established pharmacophore. While chlorambucil is known to alkylate DNA, the RAPTA complexes are known to coordinate to amino acid side chains of proteins. Therefore, such a molecule combines DNA and protein targeting properties in a single molecule. Several chlorambucil-tethered RAPTA derivatives were prepared and tested for their cytotoxicity, stability in water and reactivity to protein and DNA substrates. The anticancer activity of the complexes is widely driven by the cytotoxicity of the chlorambucil moiety. However, especially in the cis-platin-resistant A2780R cells, the chlorambucil-functionalized RAPTA derivatives are in general more cytotoxic than chlorambucil and also a mixture of chlorambucil and the parent organoruthenium RAPTA compound. In a proof-of-principle experiment, the cross-linking of DNA and protein fragments by a chlorambucil-RAPTA derivative was observed

Genome-Wide Mycobacterium tuberculosis Variation (GMTV) Database: A New Tool for Integrating Sequence Variations and Epidemiology

Background Tuberculosis (TB) poses a worldwide threat due to advancing multidrug-resistant strains and deadly co-infections with Human immunodeficiency virus. Today large amounts of Mycobacterium tuberculosis whole genome sequencing data are being assessed broadly and yet there exists no comprehensive online resource that connects M. tuberculosis genome variants with geographic origin, with drug resistance or with clinical outcome. Description Here we describe a broadly inclusive unifying Genome-wide Mycobacterium tuberculosis Variation (GMTV) database, (http://mtb.dobzhanskycenter.org) that catalogues genome variations of M. tuberculosis strains collected across Russia. GMTV contains a broad spectrum of data derived from different sources and related to M. tuberculosis molecular biology, epidemiology, TB clinical outcome, year and place of isolation, drug resistance profiles and displays the variants across the genome using a dedicated genome browser. GMTV database, which includes 1084 genomes and over 69,000 SNP or Indel variants, can be queried about M. tuberculosis genome variation and putative associations with drug resistance, geographical origin, and clinical stages and outcomes. Conclusions Implementation of GMTV tracks the pattern of changes of M. tuberculosis strains in different geographical areas, facilitates disease gene discoveries associated with drug resistance or different clinical sequelae, and automates comparative genomic analyses among M. tuberculosis strains

Influence of the Number of Axial Bexarotene Ligands on the Cytotoxicity of Pt(IV) Analogs of Oxaliplatin

We present the synthesis and cytotoxic potencies of new Pt(IV) complexes with bexarotene, an anticancer drug that induces cell differentiation and apoptosis via selective activation of retinoid X receptors. In these complexes bexarotene is positioned as an axial ligand. The complex of one bexarotene ligand attached to Pt(IV) oxaliplatin moiety was potent whereas its counterpart carrying two bexarotene ligands was inactive

Unusual Large-Scale Chromosomal Rearrangements in <i>Mycobacterium tuberculosis</i> Beijing B0/W148 Cluster Isolates

<div><p>The <i>Mycobacterium tuberculosis</i> (MTB) Beijing family isolates are geographically widespread, and there are examples of Beijing isolates that are hypervirulent and associated with drug resistance. One-fourth of Beijing genotype isolates found in Russia belong to the B0/W148 group. The aim of the present study was to investigate features of these endemic strains on a genomic level. Four Russian clinical isolates of this group were sequenced, and the data obtained was compared with published sequences of various MTB strain genomes, including genome of strain W-148 of the same B0/W148 group. The comparison of the W-148 and H37Rv genomes revealed two independent inversions of large segments of the chromosome. The same inversions were found in one of the studied strains after deep sequencing using both the fragment and mate-paired libraries. Additionally, inversions were confirmed by RFLP hybridization analysis. The discovered rearrangements were verified by PCR in all four newly sequenced strains in the study and in four additional strains of the same Beijing B0/W148 group. The other 32 MTB strains from different phylogenetic lineages were tested and revealed no inversions. We suggest that the initial largest inversion changed the orientation of the three megabase (Mb) segment of the chromosome, and the second one occurred in the previously inverted region and partly restored the orientation of the 2.1 Mb inner segment of the region. This is another remarkable example of genomic rearrangements in the MTB in addition to the recently published of large-scale duplications. The described cases suggest that large-scale genomic rearrangements in the currently circulating MTB isolates may occur more frequently than previously considered, and we hope that further studies will help to determine the exact mechanism of such events.</p></div

Genome rearrangements' representation for W-148 Progenitor I like H37Rv, W-148 Progenitor II and W-148 genomes.

<p>Each local collinear block (LCB) I–V is represented by a different color. Upside-down blocks (LCBs II and IV) represent the location of the reverse strand, which means an inversion has occurred. Asterisk indicates a terminus of a replication site. Terminus of a replication site was calculated based on GraphDNA (GC-skew mode) software <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084971#pone.0084971-Thomas1" target="_blank">[19]</a>.</p

Schematic presentation of duplicated bases flanking the IS<i>6110</i> insertion sites between LCBs II&III and III&IV.

<p>Schematic presentation of duplicated bases flanking the IS<i>6110</i> insertion sites between LCBs II&III and III&IV.</p

Results of PCR verification of inversions.

<p>Electrophoregram of PCR products obtained for MTB strains during the amplification with primer sets 1–8 (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084971#pone-0084971-t003" target="_blank">Table 3</a>).(A) SP 21 B0/W148 Beijing strain and (B) SP 5 non-B0/W148 Beijing strain. Lanes 1–8 correspond to primer sets 1–8; M is a marker GeneRuler 100 bp Plus DNA Ladder (Fermentas, SM0324); K- is a negative control.</p

Genotyping and drug resistance data of the B0/W148 strains sequenced in this study.

<p>¹ RIF - rifampicin, INH - isoniazid, EMB - ethambutol, STR - streptomycin, PZA - pyrazinamide, ETH - ethionamide, AMI- amikacin, CAPR - capreomycin, OFL – ofloxacin.</p><p>² B0 designation according to Narvskaya <i>et al.</i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084971#pone.0084971-Narvskaya1" target="_blank">[6]</a>, W148 according to Bifani <i>et al.</i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084971#pone.0084971-Bifani1" target="_blank">[14]</a>.</p><p>³ SITVITWEB was used for identification of data <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084971#pone.0084971-Demay1" target="_blank">[15]</a>.</p><p>⁴ 24 – VNTR: s154, s580, s960, s1644, s2059, s2531, s2687, s2996, s3007, s3192, s4348, s802, s2165, s2461, s577, s2163, s4052, s4156, s424, s1955, s2347, s2401, s3171, s3690 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084971#pone.0084971-Supply1" target="_blank">[16]</a>.</p