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Biology subjects

Evers, M.

Publications and source records attributed to Evers, M..

6 recordsLinked to original sources

Tumor-Derived SPP1 Drives Immunosuppressive Macrophage Reprogramming in Gastric Peritoneal Carcinomatosis

Peritoneal carcinomatosis is a major cause of death in gastric cancer, yet effective therapies remain limited. Tumor-derived soluble factors are increasingly recognized as key regulators of the peritumoral microenvironment. Here, we nominate osteopontin (SPP1) as a tumor-derived mediator that orchestrates macrophage-driven immunoregulation in gastric peritoneal carcinomatosis. Using integrated analyses of human clinical datasets and murine models, we demonstrate that tumor-secreted SPP1 promotes macrophage recruitment and induces tolerogenic IL-10 production. Clinically, SPP1 correlated with inferior overall survival and progression-free survival in gastric cancer. In syngeneic murine models of gastric peritoneal carcinomatosis, intracavitary pharmacologic inhibition of SPP1 restricted peritoneal dissemination, impaired macrophage infiltration and suppressed IL-10 production. Consistent with these findings, macrophage depletion phenocopied antitumor effects of SPP1 inhibition, resulting in decreased metastatic burden. Collectively, these findings define a mechanism of tumor-macrophage crosstalk that promotes peritoneal dissemination and provide a rationale for therapeutic targeting of SPP1 in gastric peritoneal carcinomatosis.

Cancer Biology↗

Novel RNA Polymerase I and Cyclin Dependent Kinase combination therapy for the treatment of aggressive Acute Myeloid Leukemia.

Despite advances in therapy, specific subtypes Acute Myeloid Leukaemia (AML) remains largely incurable. The first-in-class RNA Polymerase I (Pol I) inhibitor, CX-5461, has demonstrated promising activity in both haematological malignancies and solid tumours by selectively inhibiting ribosome biogenesis to induce nucleolar stress, a critical vulnerability in rapidly proliferating cancer cells. CX-5461 has undergone clinical trials for the treatment of both solid and haematological malignancies, and 2nd generation Pol I inhibitor PMR-116 has also entered clinical trials, underscoring the translational potential of drugs that target RNA Polymerase I. To enhance the therapeutic efficacy of Pol I inhibition and prevent the emergence of resistance, we conducted a cell line-based unbiased screen of FDA-approved drugs to identify compounds that might synergise with CX-5461. This screen revealed that the pan-CDK inhibitors Dinaciclib and Flavopiridol enhance nucleolar stress pathway (NSP) activation and are strong candidates for combinatorial therapy with CX-5461. Further analysis showed that the combination of CX-5461 and Dinaciclib acts synergistically across a genetically diverse panel of human AML cell lines. This synergy is dependent on an intact NSP, with both agents independently stabilising p53, but with distinct phenotypic outcomes: Dinaciclib induces rapid apoptosis, whereas CX-5461 primarily enforces cell cycle arrest. This functional complementarity results in efficient tumour cell clearance and likely accounts for the delayed onset of therapy resistance. Importantly, combination treatment with CX-5461 and Dinaciclib significantly improved survival in murine models of AML and reduced colony formation in primary human AML samples. Together these findings provide preclinical evidence for a novel combination treatment strategy that leverages nucleolar stress and cell cycle control to enhance treatment outcomes in AML, paving the way for clinical translation of Pol I-CDK co-targeting therapies.

cancer biology↗

Nuclear stabilisation of p53 requires a functional nucleolar surveillance pathway

The nucleolar surveillance pathway (NSP) monitors nucleolar fidelity and responds to nucleolar stresses (i.e., inactivation of ribosome biogenesis) by mediating the inhibitory binding of ribosomal proteins (RPs) to mouse double minute 2 homolog (MDM2), a nuclear-localised E3 ubiquitin ligase, which results in p53 accumulation. Inappropriate activation of the NSP has been implicated in the pathogenesis of collection of human diseases termed "ribosomopathies", while drugs that selectively activate the NSP are now in trials for cancer. Despite the clinical significance, the precise molecular mechanism(s) regulating the NSP remain poorly understood. Using genome-wide loss of function screens, we demonstrate the ribosome biogenesis (RiBi) axis as the most potent class of genes whose disruption stabilises p53. Furthermore, we identified a novel suite of genes critical for the NSP, including a novel mammalian protein implicated in 5S ribonucleoprotein particle (5S-RNP) biogenesis, HEATR3. By selectively disabling the NSP, we unexpectedly demonstrate that a functional NSP is required for the ability of all nuclear acting stresses tested, including DNA damage, to robustly induce p53 accumulation. Together, our data demonstrates that the NSP has evolved as the dominant central integrator of stresses that regulate nuclear p53 abundance, thus ensuring RiBi is hardwired to cellular proliferative capacity.

cell biology↗

Is Vaccination a Viable Method to Control Johnes Disease Caused by Mycobacterium avium subsp. paratuberculosis? Data from 12 Million Ovine Vaccinations and 7.6 Million Carcass Examinations in New South Wales, Australia from 1999-2009

BackgroundMycobacterium avium subsp. paratuberculosis (MAP) causes Johnes disease (or paratuberculosis), a chronic wasting disease of ruminants and other animals resulting from granulomatous enteritis. There are increasing concerns that MAP is zoonotic. The prevalence of Johnes disease is increasing worldwide. In an attempt to control an epidemic of ovine Johnes disease (OJD) in New South Wales (NSW), a government/industry sponsored voluntary vaccination/on-farm management program commenced in 2000. We report herein an observational study of changes in disease prevalence as vaccination progressed, based on abattoir surveillance data for OJD from 1999 to 2009. We also discuss the epidemiological, policy, regulatory, research, economic and sociological elements that contributed to the development of a mature control program, whose aim was to halt the epidemic spread of OJD in a naive sheep population. MethodsNSW was divided into areas of "High" (HPA), "Medium" (MPA) and "Low" (LPA) OJD prevalence. A killed whole cell vaccine (Gudair(R)) was administered to sheep from 2000 to 2009. Trained examiners evaluated the viscera of adult sheep carcasses at slaughter for gross evidence of OJD. MAP infection was confirmed by histopathology. Principal findingsFrom 2000-2009, 12 million vaccine doses were administered in NSW (91%; 10.9 million in the HPA). Many of the vaccinated flocks were suffering > 5% annual mortality in adult sheep, with some individual flocks with 10-15% losses attributable to OJD. A total of 7.6 million carcasses were examined (38%; 2.9 million from the HPA). Overall, 16% of slaughter consignments (sheep consigned to the abattoir from a single vendor) were positive for OJD, of which 94% were from the HPA. In the HPA, the percentage of animals with lesions attributable to OJD at slaughter fell progressively from 2.4% (10,406/432,860) at commencement of vaccination in 2000 to 0.8% (1,573/189,564) by 2009. Herd immunity from vaccination in the HPA was estimated at 70% by 2009. This coincided with a progressive decrease in reports of clinical disease and mortalities in vaccinated flocks. SignificanceWe show a decrease in the prevalence of lesions attributable to OJD in NSW concomitant with initiation of voluntary vaccination, on-farm management plans, abattoir monitoring and feedback of animal prevalence data to sheep producers. We conclude that a target of [≤] 1% regional prevalence of OJD affected sheep at slaughter is achievable using these interventions.

immunology↗

Psi promotes Drosophila wing growth through transcriptional repression of key developmental networks

Psi, the sole FUSE Binding Protein (FUBP) family single stranded DNA/RNA binding protein in Drosophila, is essential for proper cell and tissue growth, however its mechanism of function remains unclear. Here we use Targeted DamID combined with RNA-sequencing to generate the first genome-wide binding and expression profiles for Psi. Surprisingly, we demonstrate Psi drives growth in the Drosophila wing through transcriptional repression of key developmental pathways (e.g. Wnt, Notch and TGF{beta}). Thus, Psi patterns tissue growth by directly repressing transcription of developmental growth suppressors. Analysis of direct Psi targets identified novel growth inhibitors, including Tolkin (Zinc metallopeptidase implicated in TGF{beta} signalling), Ephexin (Rho-GEF) and emp (CD36 scavenger receptor-related protein). Their depletion not only suppressed impaired growth associated with Psi knockdown, but alone was sufficient to drive wing overgrowth. Thus, Psi drives wing growth twofold, through direct activation of Myc and through transcriptional repression of growth inhibitors comprising core developmental pathways.

developmental biology↗

Elucidating small RNA pathways in Arabidopsis thaliana egg cells

O_LISmall RNA pathway components and small RNA profiles of flowering plant egg cells are largely unexplored, mainly because they are not easily accessible but deeply buried inside the ovary.\nC_LIO_LIWe describe here the utilization of proliferating callus tissue that adopted transcriptome features of Arabidopsis egg cell as a tool to explore small RNA pathway components and small RNA profiles in egg cells. We furthermore complement our studies with mRNA-Seq data from isolated Arabidopsis egg cells and provide data validation by promoter-reporter studies and whole mount in situ hybridization.\nC_LIO_LISequencing of small RNA libraries demonstrate the predominance of TE-derived siRNAs in the egg cell-related callus. TE-features and expression profiles suggest post-transcriptional silencing of activated Gypsy-like LTR retrotransposons, whereas the majority of class II DNA transposons belonging to Copia, CACTA, hAT-like and Mutator superfamilies are subjected to transcriptional silencing.\nC_LIO_LISmall RNA-seq furthermore led to the identification of differentially expressed known and novel miRNAs whose expression in the egg cell was verified by small RNA whole mount in situ hybridization. Both the strong expression of miRNAs in the egg-cell-adjoining synergids and the secretion of miRNAs into the micropyle suggest hitherto undescribed roles for these accessory cells in intercellular communication with the egg cell and the arriving pollen tube.\nC_LIO_LIIn conclusion, our datasets provide valuable and comprehensive resources to study small RNA pathways and small-RNA-mediated epigenetic reprogramming during egg cell differentiation and the onset of plant embryogenesis.\nC_LI

plant biology↗