MiR-142-3p is downregulated in aggressive p53 mutant mouse models of pancreatic ductal adenocarcinoma by hypermethylation of its locus

Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive disease with poor prognostic implications. This is partly due to a large proportion of PDACs carrying mutations in TP53, which impart gain-of-function characteristics that promote metastasis. There is evidence that microRNAs (miRNAs) may play a role in both gain-of-function TP53 mutations and metastasis, but this has not been fully explored in PDAC. Here we set out to identify miRNAs which are specifically dysregulated in metastatic PDAC. To achieve this, we utilised established mouse models of PDAC to profile miRNA expression in primary tumours expressing the metastasis-inducing mutant p53R172H and compared these to two control models carrying mutations, which promote tumour progression but do not induce metastasis. We show that a subset of miRNAs are dysregulated in mouse PDAC tumour tissues expressing mutant p53R172H, primary cell lines derived from mice with the same mutations and in TP53 null cells with ectopic expression of the orthologous human mutation, p53R175H. Specifically, miR-142-3p is downregulated in all of these experimental models. We found that DNA methyltransferase 1 (Dnmt1) is upregulated in tumour tissue and cell lines, which express p53R172H. Inhibition or depletion of Dnmt1 restores miR-142-3p expression. Overexpression of miR-142-3p attenuates the invasive capacity of p53R172H-expressing tumour cells. MiR-142-3p dysregulation is known to be associated with cancer progression, metastasis and the miRNA is downregulated in patients with PDAC. Here we link TP53 gain-of-function mutations to Dnmt1 expression and in turn miR-142-3p expression. Additionally, we show a correlation between expression of these genes and patient survival, suggesting that they may have potential to be therapeutic targets

Neutrophils: homing in on the myeloid mechanisms of metastasis

The metastasis cascade is complex and comprises several stages including local invasion into surrounding tissue, intravasation and survival of tumour cells in the circulation, and extravasation and colonisation of a distant site. It is increasingly clear that these processes are driven not only by signals within the tumour cells, but are also profoundly influenced by stromal cells and signals in the tumour microenvironment. Amongst the many cell types within the tumour microenvironment, immune cells such as lymphocytes, macrophages and neutrophils play a prominent role in tumour development and progression. Neutrophils, however, have only recently emerged as important players, particularly in metastasis. Here we review the current evidence suggesting a multi-faceted role for neutrophils in the metastatic cascade

Indirect Cost Recovery Rates: Why Do They Differ?

This paper reviews the history of the federal government's indirect cost recovery system and empirically examines the determinants of IRC rates. We find that, ceteris paribas schools in the Northeast have higher ICR rates, as do schools with high administrative expenses, a disproportionate number of graduate students, and larger expenditures on physical plant. Private research universities have higher ICR rates than do public research universities, but other factors turn out to explain most of this difference. Institutional characteristics relating to the mix of operations, financial characteristics, and location all play an important role in the determination of this rate, implying that there are good economic reasons for much of the observed variation in ICR rates both between and within sectors.

AKT regulates NPM dependent ARF localization and p53mut stability in tumors

Nucleophosmin (NPM) is known to regulate ARF subcellular localization and MDM2 activity in response to oncogenic stress, though the precise mechanism has remained elusive. Here we describe how NPM and ARF associate in the nucleoplasm to form a MDM2 inhibitory complex. We find that oligomerization of NPM drives nucleolar accumulation of ARF. Moreover, the formation of NPM and ARF oligomers antagonizes MDM2 association with the inhibitory complex, leading to activation of MDM2 E3-ligase activity and targeting of p53. We find that AKT phosphorylation of NPM-Ser48 prevents oligomerization that results in nucleoplasmic localization of ARF, constitutive MDM2 inhibition and stabilization of p53. We also show that ARF promotes p53 mutant stability in tumors and suppresses p73 mediated p21 expression and senescence. We demonstrate that AKT and PI3K inhibitors may be effective in treatment of therapeutically resistant tumors with elevated AKT and carrying gain of function mutations in p53. Our results show that the clinical candidate AKT inhibitor MK-2206 promotes ARF nucleolar localization, reduced p53(mut) stability and increased sensitivity to ionizing radiation in a xenograft model of pancreatic cancer. Analysis of human tumors indicates that phospho-S48-NPM may be a useful biomarker for monitoring AKT activity and in vivo efficacy of AKT inhibitor treatment. Critically, we propose that combination therapy involving PI3K-AKT inhibitors would benefit from a patient stratification rationale based on ARF and p53(mut) status

Expression of KOC, S100P, mesothelin and MUC1 in pancreatico-biliary adenocarcinomas: development and utility of a potential diagnostic immunohistochemistry panel

<b>Background</b> Pancreatico-biliary adenocarcinomas (PBA) have a poor prognosis. Diagnosis is usually achieved by imaging and/or endoscopy with confirmatory cytology. Cytological interpretation can be difficult especially in the setting of chronic pancreatitis/cholangitis. Immunohistochemistry (IHC) biomarkers could act as an adjunct to cytology to improve the diagnosis. Thus, we performed a meta-analysis and selected KOC, S100P, mesothelin and MUC1 for further validation in PBA resection specimens.<p></p> <b>Methods</b> Tissue microarrays containing tumour and normal cores in a ratio of 3:2, from 99 surgically resected PBA patients, were used for IHC. IHC was performed on an automated platform using antibodies against KOC, S100P, mesothelin and MUC1. Tissue cores were scored for staining intensity and proportion of tissue stained using a Histoscore method (range, 0–300). Sensitivity and specificity for individual biomarkers, as well as biomarker panels, were determined with different cut-offs for positivity and compared by summary receiver operating characteristic (ROC) curve.<p></p> <b>Results</b> The expression of all four biomarkers was high in PBA versus normal ducts, with a mean Histoscore of 150 vs. 0.4 for KOC, 165 vs. 0.3 for S100P, 115 vs. 0.5 for mesothelin and 200 vs. 14 for MUC1 (p < .0001 for all comparisons). Five cut-offs were carefully chosen for sensitivity/specificity analysis. Four of these cut-offs, namely 5%, 10% or 20% positive cells and Histoscore 20 were identified using ROC curve analysis and the fifth cut-off was moderate-strong staining intensity. Using 20% positive cells as a cut-off achieved higher sensitivity/specificity values: KOC 84%/100%; S100P 83%/100%; mesothelin 88%/92%; and MUC1 89%/63%. Analysis of a panel of KOC, S100P and mesothelin achieved 100% sensitivity and 99% specificity if at least 2 biomarkers were positive for 10% cut-off; and 100% sensitivity and specificity for 20% cut-off.<p></p> <b>Conclusion</b> A biomarker panel of KOC, S100P and mesothelin with at least 2 biomarkers positive was found to be an optimum panel with both 10% and 20% cut-offs in resection specimens from patients with PBA.<p></p&gt

Functional connectivity dynamics slow with descent from wakefulness to sleep

© 2019 El-Baba et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The transition from wakefulness to sleep is accompanied by widespread changes in brain functioning. Here we investigate the implications of this transition for interregional functional connectivity and their dynamic changes over time. Simultaneous EEG-fMRI was used to measure brain functional activity of 21 healthy participants as they transitioned from wakefulness into sleep. fMRI volumes were independent component analysis (ICA)-decomposed, yielding 42 neurophysiological sources. Static functional connectivity (FC) was estimated from independent component time courses. A sliding window method and k-means clustering (k = 7, L2-norm) were used to estimate dynamic FC. Static FC in Wake and Stage-2 Sleep (NREM2) were largely similar. By contrast, FC dynamics across wake and sleep differed, with transitions between FC states occurring more frequently during wakefulness than during NREM2. Evidence of slower FC dynamics during sleep is discussed in relation to sleep-related reductions in effective connectivity and synaptic strength

RelA regulates CXCL1/CXCR2-dependent oncogene-induced senescence in murine Kras-driven pancreatic carcinogenesis

Tumor suppression that is mediated by oncogene-induced senescence (OIS) is considered to function as a safeguard during development of pancreatic ductal adenocarcinoma (PDAC). However, the mechanisms that regulate OIS in PDAC are poorly understood. Here, we have determined that nuclear RelA reinforces OIS to inhibit carcinogenesis in the Kras mouse model of PDAC. Inactivation of RelA accelerated pancreatic lesion formation in Kras mice by abrogating the senescence-associated secretory phenotype (SASP) gene transcription signature. Using genetic and pharmacological tools, we determined that RelA activation promotes OIS via elevation of the SASP factor CXCL1 (also known as KC), which activates CXCR2, during pancreatic carcinogenesis. In Kras mice, pancreas-specific inactivation of CXCR2 prevented OIS and was correlated with increased tumor proliferation and decreased survival. Moreover, reductions in CXCR2 levels were associated with advanced neoplastic lesions in tissue from human pancreatic specimens. Genetically disabling OIS in Kras mice caused RelA to promote tumor proliferation, suggesting a dual role for RelA signaling in pancreatic carcinogenesis. Taken together, our data suggest a pivotal role for RelA in regulating OIS in preneoplastic lesions and implicate the RelA/CXCL1/CXCR2 axis as an essential mechanism of tumor surveillance in PDAC

mTORC2 signaling drives the development and progression of pancreatic cancer

mTOR signaling controls several critical cellular functions and is deregulated in many cancers, including pancreatic cancer. To date, most efforts have focused on inhibiting the mTORC1 complex. However, clinical trials of mTORC1 inhibitors in pancreatic cancer have failed, raising questions about this therapeutic approach. We employed a genetic approach to delete the obligate mTORC2 subunit Rictor and identified the critical times during which tumorigenesis requires mTORC2 signaling. Rictor deletion resulted in profoundly delayed tumorigenesis. Whereas previous studies showed most pancreatic tumors were insensitive to rapamycin, treatment with a dual mTORC1/2 inhibitor strongly suppressed tumorigenesis. In late-stage tumor-bearing mice, combined mTORC1/2 and PI3K inhibition significantly increased survival. Thus, targeting mTOR may be a potential therapeutic strategy in pancreatic cancer

The senescence-associated secretory phenotype induces cellular plasticity and tissue regeneration

Senescence is a form of cell cycle arrest induced by stress such as DNA damage and oncogenes. However, while arrested, senescent cells secrete a variety of proteins collectively known as the senescence-associated secretory phenotype (SASP), which can reinforce the arrest and induce senescence in a paracrine manner. However, the SASP has also been shown to favor embryonic development, wound healing, and even tumor growth, suggesting more complex physiological roles than currently understood. Here we uncover timely new functions of the SASP in promoting a proregenerative response through the induction of cell plasticity and stemness. We show that primary mouse keratinocytes transiently exposed to the SASP exhibit increased expression of stem cell markers and regenerative capacity in vivo. However, prolonged exposure to the SASP causes a subsequent cell-intrinsic senescence arrest to counter the continued regenerative stimuli. Finally, by inducing senescence in single cells in vivo in the liver, we demonstrate that this activates tissue-specific expression of stem cell markers. Together, this work uncovers a primary and beneficial role for the SASP in promoting cell plasticity and tissue regeneration and introduces the concept that transient therapeutic delivery of senescent cells could be harnessed to drive tissue regeneration