AKT-independent PI3-K signaling in cancer - emerging role for SGK3

The phosphoinositide 3-kinase (PI3-K) signaling pathway plays an important role in a wide variety of fundamental cellular processes, largely mediated via protein kinase B/v-akt murine thymoma viral oncogene homolog (PKB/AKT) signaling. Given the crucial role of PI3-K/AKT signaling in regulating processes such as cell growth, proliferation, and survival, it is not surprising that components of this pathway are frequently dysregulated in cancer, making the AKT kinase family members important therapeutic targets. The large number of clinical trials currently evaluating PI3-K pathway inhibitors as a therapeutic strategy further emphasizes this. The serum- and glucocorticoid-inducible protein kinase (SGK) family is made up of three isoforms, SGK1, 2, and 3, that are PI3-K-dependent, serine/threonine kinases, with similar substrate specificity to AKT. Consequently, the SGK family also regulates similar cell processes to the AKT kinases, including cell proliferation and survival. Importantly, there is emerging evidence demonstrating that SGK3 plays a critical role in AKT-independent oncogenic signaling. This review will focus on the role of SGK3 as a key effector of AKT-independent PI3-K oncogenic signaling

Banking from Leeds, not London: regional strategy and structure at the Yorkshire Bank, 1859–1952

Industrial philanthropist Edward Akroyd created the Yorkshire Penny Savings Bank in 1859. Despite competition from the Post Office Savings Bank after 1861 and a serious reserve problem in 1911, it sustained his overall strategy to become a successful regional bank. Using archival and contemporary sources to build on recent scholarship illustrating how savings banks were integrated into local economies and the complementary roles of philanthropy and paternalism, we analyse an English regional bank's strategy, including an assessment of strategic innovation, ownership changes and management structure. This will demonstrate that the founder's vision continued, even though the 1911 crisis radically altered both strategy and structure

Main-Belt Comet P/2012 T1 (PANSTARRS)

We present initial results from observations and numerical analyses aimed at characterizing main-belt comet P/2012 T1 (PANSTARRS). Optical monitoring observations were made between October 2012 and February 2013 using the University of Hawaii 2.2 m telescope, the Keck I telescope, the Baade and Clay Magellan telescopes, Faulkes Telescope South, the Perkins Telescope at Lowell Observatory, and the Southern Astrophysical Research (SOAR) telescope. The object's intrinsic brightness approximately doubles from the time of its discovery in early October until mid-November and then decreases by ~60% between late December and early February, similar to photometric behavior exhibited by several other main-belt comets and unlike that exhibited by disrupted asteroid (596) Scheila. We also used Keck to conduct spectroscopic searches for CN emission as well as absorption at 0.7 microns that could indicate the presence of hydrated minerals, finding an upper limit CN production rate of QCN<1.5x10^23 mol/s, from which we infer a water production rate of QH2O<5x10^25 mol/s, and no evidence of the presence of hydrated minerals. Numerical simulations indicate that P/2012 T1 is largely dynamically stable for >100 Myr and is unlikely to be a recently implanted interloper from the outer solar system, while a search for potential asteroid family associations reveal that it is dynamically linked to the ~155 Myr-old Lixiaohua asteroid family.Comment: 15 pages, 4 figures, accepted for publication in ApJ Letter

rDNA Chromatin Activity Status as a Biomarker of Sensitivity to the RNA Polymerase I Transcription Inhibitor CX-5461

Hyperactivation of RNA polymerase I (Pol I) transcription of ribosomal RNA (rRNA) genes (rDNA) is a key determinant of growth and proliferation and a consistent feature of cancer cells. We have demonstrated that inhibition of rDNA transcription by the Pol I transcription inhibitor CX-5461 selectively kills tumor cells in vivo. Moreover, the first-in human trial of CX-5461 has demonstrated CX-5461 is well-tolerated in patients and has single-agent anti-tumor activity in hematologic malignancies. However, the mechanisms underlying tumor cell sensitivity to CX-5461 remain unclear. Understanding these mechanisms is crucial for the development of predictive biomarkers of response that can be utilized for stratifying patients who may benefit from CX-5461. The rDNA repeats exist in four different and dynamic chromatin states: inactive rDNA can be either methylated silent or unmethylated pseudo-silent; while active rDNA repeats are described as either transcriptionally competent but non-transcribed or actively transcribed, depending on the level of rDNA promoter methylation, loading of the essential rDNA chromatin remodeler UBF and histone marks status. In addition, the number of rDNA repeats per human cell can reach hundreds of copies. Here, we tested the hypothesis that the number and/or chromatin status of the rDNA repeats, is a critical determinant of tumor cell sensitivity to Pol I therapy. We systematically examined a panel of ovarian cancer (OVCA) cell lines to identify rDNA chromatin associated biomarkers that might predict sensitivity to CX-5461. We demonstrated that an increased proportion of active to inactive rDNA repeats, independent of rDNA copy number, determines OVCA cell line sensitivity to CX-5461. Further, using zinc finger nuclease genome editing we identified that reducing rDNA copy number leads to an increase in the proportion of active rDNA repeats and confers sensitivity to CX-5461 but also induces genome-wide instability and sensitivity to DNA damage. We propose that the proportion of active to inactive rDNA repeats may serve as a biomarker to identify cancer patients who will benefit from CX-5461 therapy in future clinical trials. The data also reinforces the notion that rDNA instability is a threat to genomic integrity and cellular homeostasis.This work was supported by the National Health and Medical Research Council (NHMRC) of Australia project grants (#1100654 and #1162052). RH and RP were supported by NHMRC fellowships. AG was supported by the New Zealand Marsden Fund (14-MAU-053)

The RNA polymerase I transcription inhibitor CX-5461 cooperates with topoisomerase 1 inhibition by enhancing the DNA damage response in homologous recombination-proficient high-grade serious ovarian cancer

Background: Intrinsic and acquired drug resistance represent fundamental barriers to the cure of high-grade serous ovarian carcinoma (HGSC), the most common histological subtype accounting for the majority of ovarian cancer deaths. Defects in homologous recombination (HR) DNA repair are key determinants of sensitivity to chemotherapy and poly-ADP ribose polymerase inhibitors. Restoration of HR is a common mechanism of acquired resistance that results in patient mortality, highlighting the need to identify new therapies targeting HR-proficient disease. We have shown promise for CX-5461, a cancer therapeutic in early phase clinical trials, in treating HR-deficient HGSC. Methods: Herein, we screen the whole protein-coding genome to identify potential targets whose depletion cooperates with CX-5461 in HR-proficient HGSC. Results: We demonstrate robust proliferation inhibition in cells depleted of DNA topoisomerase 1 (TOP1). Combining the clinically used TOP1 inhibitor topotecan with CX-5461 potentiates a G2/M cell cycle checkpoint arrest in multiple HR-proficient HGSC cell lines. The combination enhances a nucleolar DNA damage response and global replication stress without increasing DNA strand breakage, significantly reducing clonogenic survival and tumour growth in vivo. Conclusions: Our findings highlight the possibility of exploiting TOP1 inhibition to be combined with CX-5461 as a non-genotoxic approach in targeting HR-proficient HGSC.The China Scholarship Council University of Melbourne Ph.D. Scholarship supported S.Y. A National Health and Medical Research Council (NHMRC) Grant and NHMRC Senior Research Fellowship to R.B.P. supported this work. The Victorian Centre for Functional Genomics (K.J.S.) is funded by the Australian Cancer Research Foundation (ACRF), the Australian Phenomics Network (APN) through funding from the Australian Government’s National Collaborative Research Infrastructure Strategy (NCRIS) programme, the Peter MacCallum Cancer Centre Foundation and the University of Melbourne Research Collaborative Infrastructure Programm

Cell cycle and growth stimuli regulate different steps of RNA polymerase I transcription

Transcription of the ribosomal RNA genes (rDNA) by RNA polymerase I (Pol I) is a major control step for ribosome synthesis and is tightly linked to cellular growth. However, the question of whether this process is modulated primarily at the level of transcription initiation or elongation is controversial. Studies in markedly different cell types have identified either initiation or elongation as the major control point. In this study, we have re-examined this question in NIH3T3 fibroblasts using a combination of metabolic labeling of the 47S rRNA, chromatin immunoprecipitation analysis of Pol I and overexpression of the transcription initiation factor Rrn3. Acute manipulation of growth factor levels altered rRNA synthesis rates over 8-fold without changing Pol I loading onto the rDNA. In fact, robust changes in Pol I loading were only observed under conditions where inhibition of rDNA transcription was associated with chronic serum starvation or cell cycle arrest. Overexpression of the transcription initiation factor Rrn3 increased loading of Pol I on the rDNA but failed to enhance rRNA synthesis in either serum starved, serum treated or G0/G1 arrested cells. Together these data suggest that transcription elongation is rate limiting for rRNA synthesis. We propose that transcription initiation is required for rDNA transcription in response to cell cycle cues, whereas elongation controls the dynamic range of rRNA synthesis output in response to acute growth factor modulation

Consensus statement on surgical pathology of the aorta from the Society for Cardiovascular Pathology and the Association for European Cardiovascular Pathology: I. Inflammatory diseases

Abstract Inflammatory diseases of the aorta include routine atherosclerosis, aortitis, periaortitis, and atherosclerosis with excessive inflammatory responses, such as inflammatory atherosclerotic aneurysms. The nomenclature and histologic features of these disorders are reviewed and discussed. In addition, diagnostic criteria are provided to distinguish between these disorders in surgical pathology specimens. An initial classification scheme is provided for aortitis and periaortitis based on the pattern of the inflammatory infiltrate: granulomatous/giant cell pattern, lymphoplasmacytic pattern, mixed inflammatory pattern, and the suppurative pattern. These inflammatory patterns are discussed in relation to specific systemic diseases including giant cell arteritis, Takayasu arteritis, granulomatosis with polyangiitis (Wegener's), rheumatoid arthritis, sarcoidosis, ankylosing spondylitis, Cogan syndrome, Behcet's disease, relapsing polychondritis, syphilitic aortitis, and bacterial and fungal infections

Deregulation of MYCN, LIN28B and LET7 in a Molecular Subtype of Aggressive High-Grade Serous Ovarian Cancers

Molecular subtypes of serous ovarian cancer have been recently described. Using data from independent datasets including over 900 primary tumour samples, we show that deregulation of the Let-7 pathway is specifically associated with the C5 molecular subtype of serous ovarian cancer. DNA copy number and gene expression of HMGA2, alleles of Let-7, LIN28, LIN28B, MYC, MYCN, DICER1, and RNASEN were measured using microarray and quantitative reverse transcriptase PCR. Immunohistochemistry was performed on 127 samples using tissue microarrays and anti-HMGA2 antibodies. Fluorescence in situ hybridisation of bacterial artificial chromosomes hybridized to 239 ovarian tumours was used to measure translocation at the LIN28B locus. Short interfering RNA knockdown in ovarian cell lines was used to test the functionality of associations observed. Four molecular subtypes (C1, C2, C4, C5) of high-grade serous ovarian cancers were robustly represented in each dataset and showed similar pattern of patient survival. We found highly specific activation of a pathway involving MYCN, LIN28B, Let-7 and HMGA2 in the C5 molecular subtype defined by MYCN amplification and over-expression, over-expression of MYCN targets including the Let-7 repressor LIN28B, loss of Let-7 expression and HMGA2 amplification and over-expression. DICER1, a known Let-7 target, and RNASEN were over-expressed in C5 tumours. We saw no evidence of translocation at the LIN28B locus in C5 tumours. The reported interaction between LIN28B and Let-7 was recapitulated by siRNA knockdown in ovarian cancer cell lines. Our results associate deregulation of MYCN and downstream targets, including Let-7 and oncofetal genes, with serous ovarian cancer. We define for the first time how elements of an oncogenic pathway, involving multiple genes that contribute to stem cell renewal, is specifically altered in a molecular subtype of serous ovarian cancer. By defining the drivers of a molecular subtype of serous ovarian cancers we provide a novel strategy for targeted therapeutic intervention

Activation of Type I and III Interferon Signalling Pathways Occurs in Lung Epithelial Cells Infected with Low Pathogenic Avian Influenza Viruses

The host response to the low pathogenic avian influenza (LPAI) H5N2, H5N3 and H9N2 viruses were examined in A549, MDCK, and CEF cells using a systems-based approach. The H5N2 and H5N3 viruses replicated efficiently in A549 and MDCK cells, while the H9N2 virus replicated least efficiently in these cell types. However, all LPAI viruses exhibited similar and higher replication efficiencies in CEF cells. A comparison of the host responses of these viruses and the H1N1/WSN virus and low passage pH1N1 clinical isolates was performed in A549 cells. The H9N2 and H5N2 virus subtypes exhibited a robust induction of Type I and Type III interferon (IFN) expression, sustained STAT1 activation from between 3 and 6 hpi, which correlated with large increases in IFN-stimulated gene (ISG) expression by 10 hpi. In contrast, cells infected with the pH1N1 or H1N1/WSN virus showed only small increases in Type III IFN signalling, low levels of ISG expression, and down-regulated expression of the IFN type I receptor. JNK activation and increased expression of the pro-apoptotic XAF1 protein was observed in A549 cells infected with all viruses except the H1N1/WSN virus, while MAPK p38 activation was only observed in cells infected with the pH1N1 and the H5 virus subtypes. No IFN expression and low ISG expression levels were generally observed in CEF cells infected with either AIV, while increased IFN and ISG expression was observed in response to the H1N1/WSN infection. These data suggest differences in the replication characteristics and antivirus signalling responses both among the different LPAI viruses, and between these viruses and the H1N1 viruses examined. These virus-specific differences in host cell signalling highlight the importance of examining the host response to avian influenza viruses that have not been extensively adapted to mammalian tissue culture

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead