Squalamine: An Appropriate Strategy against the Emergence of Multidrug Resistant Gram-Negative Bacteria?

We reported that squalamine is a membrane-active molecule that targets the membrane integrity as demonstrated by the ATP release and dye entry. In this context, its activity may depend on the membrane lipid composition. This molecule shows a preserved activity against bacterial pathogens presenting a noticeable multi-resistance phenotype against antibiotics such as polymyxin B. In this context and because of its structure, action and its relative insensitivity to efflux resistance mechanisms, we have demonstrated that squalamine appears as an alternate way to combat MDR pathogens and by pass the gap regarding the failure of new active antibacterial molecules

Gene expression profiling of patient‐derived pancreatic cancer xenografts predicts sensitivity to the BET bromodomain inhibitor JQ1: implications for individualized medicine efforts

Abstract c‐MYC controls more than 15% of genes responsible for proliferation, differentiation, and cellular metabolism in pancreatic as well as other cancers making this transcription factor a prime target for treating patients. The transcriptome of 55 patient‐derived xenografts show that 30% of them share an exacerbated expression profile of MYC transcriptional targets (MYC‐high). This cohort is characterized by a high level of Ki67 staining, a lower differentiation state, and a shorter survival time compared to the MYC‐low subgroup. To define classifier expression signature, we selected a group of 10 MYC target transcripts which expression is increased in the MYC‐high group and six transcripts increased in the MYC‐low group. We validated the ability of these markers panel to identify MYC‐high patient‐derived xenografts from both: discovery and validation cohorts as well as primary cell cultures from the same patients. We then showed that cells from MYC‐high patients are more sensitive to JQ1 treatment compared to MYC‐low cells, in monolayer, 3D cultured spheroids and in vivo xenografted tumors, due to cell cycle arrest followed by apoptosis. Therefore, these results provide new markers and potentially novel therapeutic modalities for distinct subgroups of pancreatic tumors and may find application to the future management of these patients within the setting of individualized medicine clinics

Pivotal Role of the Chromatin Protein Nupr1 in Kras-Induced Senescence and Transformation

Nupr1 is a chromatin protein, which cooperates with Kras(G12D) to induce PanIN formation and pancreatic cancer development in mice, though the molecular mechanisms underlying this effect remain to be fully characterized. In the current study, we report that Nupr1 acts as a gene modifier of the effect of Kras(G12D)-induced senescence by regulating Dnmt1 expression and consequently genome-wide levels of DNA methylation. Congruently, 5-aza-2'-deoxycytydine, a general inhibitor of DNA methylation, reverses the Kras(G12D)-induced PanIN development by promoting senescence. This requirement of Nupr1 expression, however, is not restricted to the pancreas since in lung of Nupr1(-/-) mice the expression of Kras(G12D) induces senescence instead of transformation. Therefore, mechanistically this data reveals that epigenetic events, at least at the level of DNA methylation, modulate the functional outcome of common genetic mutations, such as Kras(G12D), during carcinogenesis. The biomedical relevance of these findings lies in that they support the rational for developing similar therapeutic interventions in human aimed at controlling either the initiation or progression of cancer.Fil: Grasso, Daniel Hector. Centre de Recherche en Cancérologie de Marseille; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Bintz, Jennifer. Centre de Recherche en Cancérologie de Marseille; FranciaFil: Lomberk, Gwen. Mayo Clinic; Estados UnidosFil: Molejon, Maria Ines. Centre de Recherche en Cancérologie de Marseille; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Loncle, Celine. Centre de Recherche en Cancérologie de Marseille; FranciaFil: Garcia, Maria Noé. Centre de Recherche en Cancérologie de Marseille; FranciaFil: Lopez Millian, Maria Belen. Centre de Recherche en Cancérologie de Marseille; FranciaFil: Urrutia, Raul. Mayo Clinic; Estados UnidosFil: Iovanna, Juan. Centre de Recherche en Cancérologie de Marseille; Franci

IER3 supports KRASG12D-dependent pancreatic cancer development by sustaining ERK1/2 phosphorylation

Activating mutations in the KRAS oncogene are prevalent in pancreatic ductal adenocarcinoma (PDAC). We previously demonstrated that pancreatic intraepithelial neoplasia (PanIN) formation, which precedes malignant transformation, associates with the expression of immediate early response 3 (Ier3) as part of a prooncogenic transcriptional pathway. Here, we evaluated the role of IER3 in PanIN formation and PDAC development. In human pancreatic cancer cells, IER3 expression efficiently sustained ERK1/2 phosphorylation by inhibiting phosphatase PP2A activity. Moreover, IER3 enhanced KrasG12D-dependent oncogenesis in the pancreas, as both PanIN and PDAC development were delayed in IER3-deficient KrasG12D mice. IER3 expression was discrete in healthy acinar cells, becoming highly prominent in peritumoral acini, and particularly high in acinar ductal metaplasia (ADM) and PanIN lesions, where IER3 colocalized with phosphorylated ERK1/2. However, IER3 was absent in undifferentiated PDAC, which suggests that the IER3-dependent pathway is an early event in pancreatic tumorigenesis. IER3 expression was induced by both mild and severe pancreatitis, which promoted PanIN formation and progression to PDAC in KrasG12D mice. In IER3-deficient mice, pancreatitis abolished KrasG12D-induced proliferation, which suggests that pancreatitis enhances the oncogenic effect of KRAS through induction of IER3 expression. Together, our data indicate that IER3 supports KRASG12D-associated oncogenesis in the pancreas by sustaining ERK1/2 phosphorylation via phosphatase PP2A inhibition.Fil: Garcia, Maria Noe. Inserm; Francia. Centre National de la Recherche Scientifique; Francia. Aix-Marseille Université; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Grasso, Daniel Hector. Aix-Marseille Université; Francia. Inserm; Francia. Centre National de la Recherche Scientifique; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Lopez Millian, Maria Belen. Aix-Marseille Université; Francia. Centre National de la Recherche Scientifique; Francia. Inserm; FranciaFil: Hamidi, Tewfik. Aix-Marseille Université; Francia. Centre National de la Recherche Scientifique; Francia. Inserm; FranciaFil: Loncle, Celine. Inserm; Francia. Centre National de la Recherche Scientifique; Francia. Aix-Marseille Université; FranciaFil: Tomasini, Richard. Aix-Marseille Université; Francia. Centre National de la Recherche Scientifique; Francia. Inserm; FranciaFil: Lomberk, Gwen. Mayo Clinic. Departments of Biochemistry and Molecular Biology, Biophysics, and Medicine; Estados UnidosFil: Porteu, Françoise. Inserm; Francia. Université de Paris XI; FranciaFil: Urrutia, Raul. Mayo Clinic. Departments of Biochemistry and Molecular Biology, Biophysics, and Medicine; Estados UnidosFil: Iovanna, Juan L.. Aix-Marseille Université; Francia. Centre National de la Recherche Scientifique; Francia. Inserm; Franci

IL17 functions through the novel REG3β-JAK2-STAT3 inflammatory pathway to promote the transition from chronic pancreatitis to pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) offers an optimal model for discovering "druggable" molecular pathways that participate in inflammation-associated cancer development. Chronic pancreatitis, a common prolonged inflammatory disease, behaves as a well-known premalignant condition that contributes to PDAC development. Although the mechanisms underlying the pancreatitis-to-cancer transition remain to be fully elucidated, emerging evidence supports the hypothesis that the actions of proinflammatory mediators on cells harboring Kras mutations promote neoplastic transformation. Recent elegant studies demonstrated that the IL17 pathway mediates this phenomenon and can be targeted with antibodies, but the downstream mechanisms by which IL17 functions during this transition are currently unclear. In this study, we demonstrate that IL17 induces the expression of REG3β, a wellknown mediator of pancreatitis, during acinar-to-ductal metaplasia and in early pancreatic intraepithelial neoplasia (PanIN) lesions. Furthermore, we found that REG3β promotes cell growth and decreases sensitivity to cell death through activation of the gp130-JAK2-STAT3-dependent pathway. Genetic inactivation of REG3β in the context of oncogenic Kras-driven PDAC resulted in reduced PanIN formation, an effect that could be rescued by administration of exogenous REG3β. Taken together, our findings provide mechanistic insight into the pathways underlying inflammation-associated pancreatic cancer, revealing a dual and contextual pathophysiologic role for REG3β during pancreatitis and PDAC initiation.Fil: Loncle, Celine. Centre de Recherche en Cancerologie de Marseille; FranciaFil: Bonjoch, Laia. Instituto de Investigación Biomédica de Barcelona.; EspañaFil: Folch Puy, Emma. Instituto de Investigación Biomédica de Barcelona.; EspañaFil: Lopez Millan, Maria Belen. Centre de Recherche en Cancerologie de Marseille; FranciaFil: Lac, Sophie. Centre de Recherche en Cancerologie de Marseille; FranciaFil: Molejon, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centre de Recherche en Cancerologie de Marseille; FranciaFil: Chuluyan, Hector Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; Argentina. Centre de Recherche en Cancerologie de Marseille; FranciaFil: Cordelier, Pierre. Centre de Recherche sur le Cancer de Toulouse; FranciaFil: Dubus, Pierre. Université de Bordeaux; FranciaFil: Lomberk, Gwen. Mayo Clinic Cancer Center; Estados UnidosFil: Urrutia, Raul. Mayo Clinic Cancer Center; Estados UnidosFil: Closa, Daniel. Instituto de Investigación Biomédica de Barcelona.; EspañaFil: Iovanna, Juan Lucio. Centre de Recherche en Cancerologie de Marseille; Franci

Measurement of squalamine concentration effect on <i>E. coli</i> ATP efflux.

<p>Measurement of squalamine concentration effect on <i>E. coli</i> ATP efflux.</p

Gram negative bacteria envelope.

<p>Gram negative bacteria envelope.</p

Measurements of squalamine interactions with various bacterial and eukaryotic lipids.

<p>Measurements of squalamine interactions with various bacterial and eukaryotic lipids.</p

Antimicrobial activities of squalamine <b>1</b>.

<p>Antimicrobial activities of squalamine <b>1</b>.</p

Effect of squalamine on bacterial membrane integrity assessed by fluorescence measurement of propidium iodide – DNA/RNA interactions.

<p>Results are expressed in relative fluorescence unit (RFU) as Mean±S.D. (n = 3, three independent experiments).</p