Ataxia-Telangiectasia Mutated Loss-of-Function Displays Variant and Tissue-Specific Differences across Tumor Types.

Purpose: Mutations in the ATM gene are common in multiple cancers, but clinical studies of therapies targeting ATM-aberrant cancers have yielded mixed results. Refinement of ATM loss of function (LOF) as a predictive biomarker of response is urgently needed.

Experimental Design: We present the first disclosure and preclinical development of a novel, selective ATR inhibitor, ART0380, and test its antitumor activity in multiple preclinical cancer models.

Small-Molecule Polθ Inhibitors Provide Safe and Effective Tumor Radiosensitization in Preclinical Models.

Purpose: DNA polymerase theta (Polθ, encoded by the POLQ gene) is a DNA repair enzyme critical for microhomology mediated end joining (MMEJ). Polθ has limited expression in normal tissues but is frequently overexpressed in cancer cells and, therefore, represents an ideal target for tumor-specific radiosensitization. In this study we evaluate whether targeting Polθ with novel small-molecule inhibitors is a feasible strategy to improve the efficacy of radiotherapy.

Discovery, Characterization, and Structure-Based Optimization of Small-Molecule In Vitro and In Vivo Probes for Human DNA Polymerase Theta.

Human DNA polymerase theta (Polθ), which is essential for microhomology-mediated DNA double strand break repair, has been proposed as an attractive target for the treatment of BRCA deficient and other DNA repair pathway defective cancers. As previously reported, we recently identified the first selective small molecule Polθ in vitro probe, (ART558), which recapitulates the phenotype of Polθ loss, and in vivo probe, (ART812), which is efficacious in a model of PARP inhibitor resistant TNBC in vivo. Here we describe the discovery, biochemical and biophysical characterization of these probes including small molecule ligand co-crystal structures with Polθ.

Polθ inhibitors elicit BRCA-gene synthetic lethality and target PARP inhibitor resistance.

To identify approaches to target DNA repair vulnerabilities in cancer, we discovered nanomolar potent, selective, low molecular weight (MW), allosteric inhibitors of the polymerase function of DNA polymerase Polθ, including ART558. ART558 inhibits the major Polθ-mediated DNA repair process, Theta-Mediated End Joining, without targeting Non-Homologous End Joining. In addition, ART558 elicits DNA damage and synthetic lethality in BRCA1- or BRCA2-mutant tumour cells and enhances the effects of a PARP inhibitor.

Interrupted breeding in a songbird migrant triggers development of nocturnal locomotor activity.

Long-distance avian migrants, e.g. Eurasian reed warblers (Acrocephalus scirpaceus), can precisely schedule events of their annual cycle.

A CRISPR Dropout Screen Identifies Genetic Vulnerabilities and Therapeutic Targets in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is an aggressive cancer with a poor prognosis, for which mainstream treatments have not changed for decades. To identify additional therapeutic targets in AML, we optimize a genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) screening platform and use it to identify genetic vulnerabilities in AML cells. We identify 492 AML-specific cell-essential genes, including several established therapeutic targets such as DOT1L, BCL2, and MEN1, and many other genes including clinically actionable candidates.

[Proteomic analysis of mitochondria from the Bos taurus heart. III. Identification of mitochondrial inner memrane proteins].

We have conducted a research of mitochindrial internal membrane proteins. This fraction has been received in the form of submitochondrial particles (SMP). SMP have been processed by trypsinum, and the received peptides have been separated from so-called "smoothfaced vesicles".

Abrogation of Wip1 expression by RITA-activated p53 potentiates apoptosis induction via activation of ATM and inhibition of HdmX.

Inactivation of the p53 tumour suppressor, either by mutation or by overexpression of its inhibitors Hdm2 and HdmX is the most frequent event in cancer. Reactivation of p53 by targeting Hdm2 and HdmX is therefore a promising strategy for therapy. However, Hdm2 inhibitors do not prevent inhibition of p53 by HdmX, which impedes p53-mediated apoptosis.

Rescue of the apoptotic-inducing function of mutant p53 by small molecule RITA.

Expression of mutant p53 correlates with poor prognosis in many tumors, therefore strategies aimed at reactivation of mutant p53 are likely to provide important benefits for treatment of tumors that are resistant to chemotherapy and radiotherapy. We have previously identified and characterized a small molecule RITA which binds p53 and induces a conformational change which prevents the binding of p53 to several inhibitors, including its own destructor MDM2. In this way, RITA rescues the tumor suppression function of wild type p53.

[Proteomic analysis of mitochondria from the Bos taurus heart. II. Identification of mitochondrial soluble proteins].

A fraction of the so-called mitochondrial soluble proteins was obtained after the destruction of purified mitochondria by sonication according to the previously found approach to the identification of protein subsets of the Bos taurus heart proteome. A tryptic destruction of these proteins was achieved. Approximately half of the tryptic hydrolysate was separated into two fractions of cysteine-containing and cysteine-free peptides by covalent chromatography on Thiopropyl Sepharose 4B.

Under cover of darkness: nocturnal life of diurnal birds.

Songbirds are generally considered diurnal, although many species show periodic nocturnal activity during migration seasons. From a breeding-range perspective, such migratory species appear to be diurnal because they are observed to nest and feed their young during the day. But are they really exclusively diurnal? The authors tested how a passerine long-distance migrant, the Eurasian reed warbler, schedules movements during the breeding period by tracking birds in 2 experimental situations: 1) Birds experienced simulated nest loss and were monitored during their search for alternative locations, and 2) birds were translocated to reed beds at distances from 2 to 21 km and tracked during homing.

Ablation of key oncogenic pathways by RITA-reactivated p53 is required for efficient apoptosis.

Targeting "oncogene addiction" is a promising strategy for anticancer therapy. We report a potent inhibition of crucial oncogenes by p53 upon reactivation by small-molecule RITA in vitro and in vivo. RITA-activated p53 unleashes the transcriptional repression of antiapoptotic proteins Mcl-1, Bcl-2, MAP4, and survivin; blocks the Akt pathway on several levels; and downregulates c-Myc, cyclin E, and beta-catenin.

[Proteomic analysis of heart mitochondria from Bos taurus. I. Application of proteomics methods to identification of transmembrane domains of proteins of the internal mitochondrial membrane].

This study is part of a large-scale investigation of the proteome of mitochondria from the heart muscle of Bos taurus. We developed a special approach to simplification of the protein mixture by separation of mitochondrial fractions with stable protein compositions. At the first stage of this approach, we isolated and purified internal mitochondrial membranes.

[The role of different kinase pathways of signal transduction in proliferation of E1A + Ras transformants].

In this paper we have explored the role of different kinase pathways of signal transduction in proliferation control of E1A + Ras transformants, using specific inhibitors of MAP-kinases ERK, JNK, p38 and PI3-kinase. According to our data, suppression of signalling cascades driven by RI3K only arrested proliferation of E1A + Ras cells, while suppression of either MAP-kinase did not lead to noticeable antiproliferative effect. We have shown that suppression of RI3K with LY294002 gave rise to accumulation of cyclin-dependent kinase inhibitor p27(KiP1) but not p21(Waf1).

[Mitochondrial H+-ATPase: identification of subunits of the F0 subcomplex contacting with membrane lipids].

The subunits of the F0 membrane sector of bovine heart mitochondrial H(+)-ATPase that contact the lipids of the mitochondrial inner membrane were identified with the use of specially synthesized proteoliposomes that contained active mitochondrial H(+)-ATPase and a photoreactive lipid, which was 1-acyl-2-[12-(diazocyclopentadiene-2-carbonylamino)-[12-14C]dodecanoyl]-sn- glycero-3-phosphocholine, 1-acyl-2-[11-([125I]diazoiodocyclopentadiene-2-carbonyloxy)undecanoyl]-sn- glycero-3-phosphocholine, or 1-acyl-2-[12-(diazocyclopentadiene-2-carbonylamino)dodecanoyl]-sn-glycero- 3-phosphocholine, where acyl is a mixture of the residues of palmitic (70%) and stearic (30%) acids. An analysis of the cross-linked products obtained upon the UV-irradiation of these proteoliposomes indicated that subunits c and a of the F0 membrane sector contact the lipids. The cross-linked products were identified by SDS-PAGE and MALDI mass spectrometry.

[Protein import into mitochondria].

This review is focused on the import of processable precursor proteins into the mitochondrial matrix; the import of carrier proteins into the inner mitochondrial membrane is also briefly discussed. Post- and cotranslational theories of the import, specific features of the presequence structures, and effects of some cytosolic factors on the import of precursor proteins are reviewed. The data on the structure of the protein translocases of the outer (TOM complex) and the inner (TIM complex) membranes of mitochondria and the current models of the precursor protein import by these translocases are also summarized.

The precursor of the F1beta subunit of the ATP synthase is covalently modified upon binding to plant mitochondrial.

We present evidence for a unique covalent modification of a nuclear-encoded precursor protein targeted to plant mitochondria. We investigated the early events of in vitro import for the mitochondrial precursor of the ATP synthase F1beta subunit from Nicotiana plumbaginifolia (pF1beta) into plant mitochondria. When pF1beta of 59 kDa was incubated with mitochondria isolated from different higher-plant species, a band of 61 kDa was generated.