Homologous Recombination Deficiency Across Subtypes of Primary Breast Cancer

Purpose - Homologous recombination deficiency (HRD) is highly prevalent in triple-negative breast cancer (TNBC) and associated with response to PARP inhibition (PARPi). Here, we studied the prevalence of HRD in non-TNBC to assess the potential for PARPi in a wider group of patients with breast cancer. Methods - HRD status was established using targeted gene panel sequencing (360 genes) and BRCA1 methylation analysis of pretreatment biopsies from 201 patients with primary breast cancer in the phase II PETREMAC trial (ClinicalTrials.gov identifier: NCT02624973). HRD was defined as mutations in BRCA1, BRCA2, BRIP1, BARD1, or PALB2 and/or promoter methylation of BRCA1 (strict definition; HRD-S). In secondary analyses, a wider definition (HRD-W) was used, examining mutations in 20 additional genes. Furthermore, tumor BRCAness (multiplex ligation-dependent probe amplification), PAM50 subtyping, RAD51 nuclear foci to test functional HRD, tumor-infiltrating lymphocyte (TIL), and PD-L1 analyses were performed. Results - HRD-S was present in 5% of non-TNBC cases (n = 9 of 169), contrasting 47% of the TNBC tumors (n = 15 of 32). HRD-W was observed in 23% of non-TNBC (n = 39 of 169) and 59% of TNBC cases (n = 19 of 32). Of 58 non-TNBC and 30 TNBC biopsies examined for RAD51 foci, 4 of 4 (100%) non-TNBC and 13 of 14 (93%) TNBC cases classified as HRD-S had RAD51 low scores. In contrast, 4 of 17 (24%) non-TNBC and 15 of 19 (79%) TNBC biopsies classified as HRD-W exhibited RAD51 low scores. Of nine non-TNBC tumors with HRD-S status, only one had a basal-like PAM50 signature. There was a high concordance between HRD-S and either BRCAness, high TIL density, or high PD-L1 expression (each P Conclusion - The prevalence of HRD in non-TNBC suggests that therapy targeting HRD should be evaluated in a wider breast cancer patient population. Strict HRD criteria should be implemented to increase diagnostic precision with respect to functional HRD

Microbial interactions : effects on virulence in Enterohaemorrhagic Escherichia coli (EHEC)

Enterohaemorrhagic Escherichia coli (EHEC) is an emerging food borne pathogen associated with a number of outbreaks worldwide, and is a serious public health threat. The symptoms of the disease can range from mild diarrhoea to severe disease, such as haemorrhagic colitis (HC), and can result in life-threatening systemic complications such as haemolytic uremic syndrome (HUS). The O157:H7 serotype is traditionally associated with severe outbreaks, however, non-O157 serotypes are becoming a significant public health concern especially in European countries and in Australia. In Norway, an outbreak of EHEC disease of serotype O103:H25 (NIPH-11060424) showed particularly high rates of HUS. The main goal of this study was to improve knowledge regarding interactions between EHEC strains and commensal bacteria in a setting where some of the environmental factors characteristic of the gastrointestinal tract were represented. To do so, the effect of coculture/ spent medium from various bacteria on gene expression in EHEC strains, the effect of the vitamin K-homologue menadione on Shiga toxin 2 (Stx2) production, and the interactions between Stx2 bacteriophages and various E. coli strains were investigated. The latter were studied in order to obtain more information about the host range of the Stx2 phage.Enterohemmorhagisk Escherichia coli (EHEC) er en voksende gruppe matbårne patogener som er assosiert med mange utbrudd og er regnet som et alvorlig folkehelseproblem. Symptomer kan variere fra mild diare til alvorlig sykdom, som utvikling av blødende tykktarmbetennelse, som videre kan føre til livstruende systemiske komplikasjoner som hemolytisk uremisk syndrom (HUS). Tradisjonelt er det serotype O157:H7 som har vært assosiert med alvorlige utbrudd, men en rekke serotyper er nå regnet som et folkehelseproblem spesielt i Europa og i Australia. I Norge hadde vi et EHEC-utbrudd grunnet en serotype O103:H25 (NIPH-11060424), hvor HUS raten var usedvanlig høy. Hovedmålet i denne studien var å øke kunnskapen om interaksjonene mellom EHEC-stammer og ulike kommensale bakterier, under betingelser der noen av miljøfaktorene karakteristisk for gastrointestinaltrakten var representert. Effekten av samkultur/supernatant fra ulike bakterier på virulensen i ulike EHEC-stammer, effekten av vitamin K-homologen menadione på Shigatoksin 2 (Stx2) produksjon, og interaksjonene mellom Stx2-bakteriofager og ulike E. coli-stammer ble undersøkt. Sistnevnte ble utført for å øke kunnskapen om smitteevnen til Stx2-bakteriofagen

Microbial interactions : effects on virulence in Enterohaemorrhagic Escherichia coli (EHEC)

Enterohaemorrhagic Escherichia coli (EHEC) is an emerging food borne pathogen associated with a number of outbreaks worldwide, and is a serious public health threat. The symptoms of the disease can range from mild diarrhoea to severe disease, such as haemorrhagic colitis (HC), and can result in life-threatening systemic complications such as haemolytic uremic syndrome (HUS). The O157:H7 serotype is traditionally associated with severe outbreaks, however, non-O157 serotypes are becoming a significant public health concern especially in European countries and in Australia. In Norway, an outbreak of EHEC disease of serotype O103:H25 (NIPH-11060424) showed particularly high rates of HUS. The main goal of this study was to improve knowledge regarding interactions between EHEC strains and commensal bacteria in a setting where some of the environmental factors characteristic of the gastrointestinal tract were represented. To do so, the effect of coculture/ spent medium from various bacteria on gene expression in EHEC strains, the effect of the vitamin K-homologue menadione on Shiga toxin 2 (Stx2) production, and the interactions between Stx2 bacteriophages and various E. coli strains were investigated. The latter were studied in order to obtain more information about the host range of the Stx2 phage

The gut bacterium Bacteroides thetaiotaomicron influences the virulence potential of the enterohemorrhagic Escherichia coli0103:H25

Enterohemorrhagic E. coli (EHEC) is associated with severe gastrointestinal disease. Upon entering the gastrointestinal tract, EHEC is exposed to a fluctuating environment and a myriad of other bacterial species. To establish an infection, EHEC strains have to modulate their gene expression according to the GI tract environment. In order to explore the interspecies interactions between EHEC and an human intestinal commensal, the global gene expression profile was determined of EHEC O103:H25 (EHEC NIPH-11060424) co-cultured with B. thetaiotaomicron (CCUG 10774) or grown in the presence of spent medium from B. thetaiotaomicron. Microarray analysis revealed that approximately 1% of the EHEC NIPH-11060424 genes were significantly up-regulated both in co-culture (30 genes) and in the presence of spent medium (44 genes), and that the affected genes differed between the two conditions. In co-culture, genes encoding structural components of the type three secretion system were among the most affected genes with an almost 4-fold up-regulation, while the most affected genes in spent medium were involved in chemotaxis and were more than 3-fold up-regulated. The operons for type three secretion system (TTSS) are located on the Locus of enterocyte effacement (LEE) pathogenicity island, and qPCR showed that genes of all five operons (LEE1-LEE5) were up-regulated. Moreover, an increased adherence to HeLa cells was observed in EHEC NIPH-11060424 exposed to B. thetaiotaomicron. Expression of stx2 genes, encoding the main virulence factor of EHEC, was down-regulated in both conditions (co-culture/spent medium). These results show that expression of EHEC genes involved in colonization and virulence is modulated in response to direct interspecies contact between cells, or to diffusible factors released from B. thetaiotaomicron. Such interspecies interactions could allow the pathogen to recognize its predilection site and modulate its behaviour accordingly, thus increasing the efficiency of colonization of the colon mucosa, facilitating its persistence and increasing its virulence potential

Vitamin K analogs influence the growth and virulence potential of enterohemorrhagic Escherichia coli

acceptedVersio

Overview workflow for microarray experiment.

<p>Overview workflow for microarray experiment.</p

The expression of <i>cheY</i> determined by qPCR in various conditions.

<p>The figure displays the relative expression of <i>cheY</i> when EHEC NIPH-11060424 is cultured in spent medium from <i>B</i>. <i>thetaiotaomicron</i>, <i>B</i>. <i>fragilis</i> and <i>C</i>. <i>perfringens</i> compared to growth in BHI. Boxes show the upper (75%) and the lower (25%) percentiles of the data. Whiskers indicate the highest and the lowest numbers.</p

Bacterial strains used in this study.

<p>^aSynonym with NVH-734</p><p>^bAlso designated VPI-5482</p><p>Bacterial strains used in this study.</p

The motility of EHEC NIPH-11060424 in spent medium from various commensals.

<p>(A) Motility of EHEC NIPH-11060424 grown in the presence of spent medium from <i>B</i>. <i>thetaiotaomicron</i> (1), <i>B</i>. <i>fragilis</i> (2) and in pure culture (filter-sterilized water) (3). (B) The size (cm) of the growth halo in the motility assay upon exposure to spent medium from <i>B</i>. <i>thetaiotaomicron and B</i>. <i>fragilis</i>. Results are given as means of three experiments, with bars showing standard error of the mean (SEM).</p