Self-assembling dendrimer nanosystems for specific fluorine magnetic resonance imaging and effective theranostic treatment of tumors.

Fluorine magnetic resonance imaging (19F-MRI) is particularly promising for biomedical applications owing to the absence of fluorine in most biological systems. However, its use has been limited by the lack of safe and water-soluble imaging agents with high fluorine contents and suitable relaxation properties. We report innovative 19F-MRI agents based on supramolecular dendrimers self-assembled by an amphiphilic dendrimer composed of a hydrophobic alkyl chain and a hydrophilic dendron. Specifically, this amphiphilic dendrimer bears multiple negatively charged terminals with high fluorine content, which effectively prevented intra- and intermolecular aggregation of fluorinated entities via electrostatic repulsion. This permitted high fluorine nuclei mobility alongside good water solubility with favorable relaxation properties for use in 19F-MRI. Importantly, the self-assembling 19F-MRI agent was able to encapsulate the near-infrared fluorescence (NIRF) agent DiR and the anticancer drug paclitaxel for multimodal 19F-MRI and NIRF imaging of and theranostics for pancreatic cancer, a deadly disease for which there remains no adequate early detection method or efficacious treatment. The 19F-MRI and multimodal 19F-MRI and NIRF imaging studies on human pancreatic cancer xenografts in mice confirmed the capability of both imaging modalities to specifically image the tumors and demonstrated the efficacy of the theranostic agent in cancer treatment, largely outperforming the clinical anticancer drug paclitaxel. Consequently, these dendrimer nanosystems constitute promising 19F-MRI agents for effective cancer management. This study offers a broad avenue to the construction of 19F-MRI agents and theranostics, exploiting self-assembling supramolecular dendrimer chemistry.

Targeting NUPR1-dependent stress granules formation to induce synthetic lethality in KrasG12D-driven tumors.

We find that NUPR1, a stress-associated intrinsically disordered protein, induced droplet formation via liquid-liquid phase separation (LLPS). NUPR1-driven LLPS was crucial for the creation of NUPR1-dependent stress granules (SGs) in pancreatic cancer cells since genetic or pharmacological inhibition by ZZW-115 of NUPR1 activity impeded SGs formation. The KrasG12D mutation induced oncogenic stress, NUPR1 overexpression, and promoted SGs development. Notably, enforced NUPR1 expression induced SGs formation independently of mutated KrasG12D. Mechanistically, KrasG12D expression strengthened sensitivity to NUPR1 inactivation, inducing cell death, activating caspase 3 and releasing LDH. Remarkably, ZZW-115-mediated SG-formation inhibition hampered the development of pancreatic intraepithelial neoplasia (PanINs) in Pdx1-cre;LSL-KrasG12D (KC) mice. ZZW-115-treatment of KC mice triggered caspase 3 activation, DNA fragmentation, and formation of the apoptotic bodies, leading to cell death, specifically in KrasG12D-expressing cells. We further demonstrated that, in developed PanINs, short-term ZZW-115 treatment prevented NUPR1-associated SGs presence. Lastly, a four-week ZZW-115 treatment significantly reduced the number and size of PanINs in KC mice. This study proposes that targeting NUPR1-dependent SGs formation could be a therapeutic approach to induce cell death in KrasG12D-dependent tumors.

Ehmt2 inactivation in pancreatic epithelial cells shapes the transcriptional landscape and inflammation response of the whole pancreas.

Introduction: The Euchromatic Histone Methyl Transferase Protein 2 (EHMT2), also known as G9a, deposits transcriptionally repressive chromatin marks that play pivotal roles in the maturation and homeostasis of multiple organs. Recently, we have shown that Ehmt2 inactivation in the mouse pancreas alters growth and immune gene expression networks, antagonizing Kras-mediated pancreatic cancer initiation and promotion. Here, we elucidate the essential role of Ehmt2 in maintaining a transcriptional landscape that protects organs from inflammation. Methods: Comparative RNA-seq studies between normal postnatal and young adult pancreatic tissue from Ehmt2 conditional knockout animals (Ehmt2 fl/fl ) targeted to the exocrine pancreatic epithelial cells (Pdx1-Cre and P48 Cre/+ ), reveal alterations in gene expression networks in the whole organ related to injury-inflammation-repair, suggesting an increased predisposition to damage. Thus, we induced an inflammation repair response in the Ehmt2 fl/fl pancreas and used a data science-based approach to integrate RNA-seq-derived pathways and networks, deconvolution digital cytology, and spatial transcriptomics. We also analyzed the tissue response to damage at the morphological, biochemical, and molecular pathology levels. Results and discussion: The Ehmt2 fl/fl pancreas displays an enhanced injury-inflammation-repair response, offering insights into fundamental molecular and cellular mechanisms involved in this process. More importantly, these data show that conditional Ehmt2 inactivation in exocrine cells reprograms the local environment to recruit mesenchymal and immunological cells needed to mount an increased inflammatory response. Mechanistically, this response is an enhanced injury-inflammation-repair reaction with a small contribution of specific Ehmt2-regulated transcripts. Thus, this new knowledge extends the mechanisms underlying the role of the Ehmt2-mediated pathway in suppressing pancreatic cancer initiation and modulating inflammatory pancreatic diseases.

EHMT2 Inactivation in Pancreatic Epithelial Cells Shapes the Transcriptional Landscape and Inflammation Response of the Whole Pancreas.

The Euchromatic Histone Methyl Transferase Protein 2 (EHMT2), also known as G9a, deposits transcriptionally repressive chromatin marks that play pivotal roles in the maturation and homeostasis of multiple organs. Recently, we have shown that EHMT2 inactivation alters growth and immune gene expression networks, antagonizing KRAS-mediated pancreatic cancer initiation and promotion. Here, we elucidate the essential role of EHMT2 in maintaining a transcriptional landscape that protects organs from inflammation. Comparative RNA-seq studies between normal postnatal and young adult pancreatic tissue from EHMT2 conditional knockout animals ( EHMT2 fl/fl ) targeted to the exocrine pancreatic epithelial cells ( Pdx1-Cre and P48 Cre/+ ), reveal alterations in gene expression networks in the whole organ related to injury-inflammation-repair, suggesting an increased predisposition to damage. Thus, we induced an inflammation repair response in the EHMT2 fl/fl pancreas and used a data science-based approach to integrate RNA-seq-derived pathways and networks, deconvolution digital cytology, and spatial transcriptomics. We also analyzed the tissue response to damage at the morphological, biochemical, and molecular pathology levels. The EHMT2 fl/fl pancreas displays an enhanced injury-inflammation-repair response, offering insights into fundamental molecular and cellular mechanisms involved in this process. More importantly, these data show that conditional EHMT2 inactivation in exocrine cells reprograms the local environment to recruit mesenchymal and immunological cells needed to mount an increased inflammatory response. Mechanistically, this response is an enhanced injury-inflammation-repair reaction with a small contribution of specific EHMT2-regulated transcripts. Thus, this new knowledge extends the mechanisms underlying the role of the EHMT2-mediated pathway in suppressing pancreatic cancer initiation and modulating inflammatory pancreatic diseases.

Activation of lysosomal iron triggers ferroptosis in cancer.

Iron catalyses the oxidation of lipids in biological membranes and promotes a form of cell death referred to as ferroptosis1-3. Identifying where this chemistry takes place in the cell can inform the design of drugs capable of inducing or inhibiting ferroptosis in various disease-relevant settings. Whereas genetic approaches have revealed underlying mechanisms of lipid peroxide detoxification1,4,5, small molecules can provide unparalleled spatiotemporal control of the chemistry at work6. Here, we show that the ferroptosis inhibitor liproxstatin-1 (Lip-1) exerts a protective activity by inactivating iron in lysosomes. Based on this, we designed the bifunctional compound fentomycin that targets phospholipids at the plasma membrane and activates iron in lysosomes upon endocytosis, promoting oxidative degradation of phospholipids and ferroptosis. Fentomycin effectively kills primary sarcoma and pancreatic ductal adenocarcinoma cells. It acts as a lipolysis-targeting chimera (LIPTAC), preferentially targeting iron-rich CD44high cell-subpopulations7,8 associated with the metastatic disease and drug resistance9,10. Furthermore, we demonstrate that fentomycin also depletes CD44high cells in vivo and reduces intranodal tumour growth in an immunocompetent murine model of breast cancer metastasis. These data demonstrate that lysosomal iron triggers ferroptosis and that lysosomal iron redox chemistry can be exploited for therapeutic benefits.

A guideline on the molecular ecosystem regulating ferroptosis.

Ferroptosis, an intricately regulated form of cell death characterized by uncontrolled lipid peroxidation, has garnered substantial interest since this term was first coined in 2012. Recent years have witnessed remarkable progress in elucidating the detailed molecular mechanisms that govern ferroptosis induction and defence, with particular emphasis on the roles of heterogeneity and plasticity. In this Review, we discuss the molecular ecosystem of ferroptosis, with implications that may inform and enable safe and effective therapeutic strategies across a broad spectrum of diseases.

Un tratamiento "a la carta" para los pacientes con adenocarcinoma pancreático / An "à la carte" treatment for patients with pancreatic adenocarcinoma

Resumen El adenocarcinoma pancreático es una enfermedad heterogénea. Sin dudas la aparición y la acumulación de mutaciones genéticas promueven el desarrollo del adenocarcinoma pancreático. Sin embargo, de manera contra-intuitiva, los análisis genéticos, por más precisos y profundos que sean, no permi ten la estratificación de los pacientes para predecir la evolución clínica ni para seleccionar el tratamiento más eficaz para cada paciente. Esto es debido a que la evolución clínica y la sensibilidad a los tratamientos están asociadas con su fenotipo, el que, a su vez, está determinado por la expresión global de los genes, es decir están regulados a nivel transcriptómico. Por lo tanto, la estratificación de esos pacientes debe hacerse a través de la lectura transcriptómica y no a través de su análisis genético. Los datos obtenidos sobre grandes cohortes de pacientes indican que el estudio de un conjunto de transcriptos seleccionados podría predecir la evolución clínica y ayudar a decidir el tratamiento más apropiado. Se está avanzando rápidamente hacia una medicina personalizada para esta enfermedad, que de por sí tiene un mal pronóstico, pero que es aún peor si la deci sión terapéutica no es la más adaptada a cada paciente. Estamos convencidos de que en un futuro próximo el tratamiento de los cánceres estará precedido por una caracterización transcriptómica extensa con el fin de seleccionar los tratamientos "a la carta" más adecuados.

Abstract Pancreatic adenocarcinoma is a heterogeneous disease. Undeniably, the appearance and accumulation of genetic muta tions promote the development of pancreatic adenocarcinoma. However, counterintuitively, genetic analyzes, no matter how precise and in-depth they may be, do not allow stratification of patients to predict their clinical evolution or to select the most effective treatment in each case. This is due to the fact that the clinical evolution and sensitivity to treatments are associated with the tumoral phenotype, which, in turn, is determined by the global expression of genes that is regulated at the transcriptomic level. Therefore, the stratification of these patients must be done by analysis at the transcriptomic level and not by genetic analysis. The data obtained from large cohorts of patients indicate that studying the transcription of a selected set of genes could predict the clinical outcome and can help to decide about the most appropriate treatment. We are moving very rapidly towards a personalized medicine for this disease, which in itself has a poor prognosis, even worse if the therapeutic deci sion is not the most adapted to each patient. We are convinced that in the near future the treatment of cancers will be preceded by an extensive transcriptomic characterization in order to select the most suitable "à la carte" treatments.

Synthesis and contents of pancreatic exportable enzymes: effect of oleic acid intraduodenal administration

Ratas Sprague-Dawley fueron estimuladas intraduadernalmente con ácido oleico y sacrificadas 20, 40, 60 y 80 m luego de la instilación. En todos los grupos se administró, 10m antes del sacrifício, 50 uCi de 3H-fenilalanina (3H-F) intraperitoneal. Se cuantificaron los niveles intrapancreáticos de Am, Chtg, Tg y Li y la incorporación de 3H-F en las proteínas secretoras. A los 40 m de la administración de ácido oleico se registró la máxima estimulación de ácido oleico se registró la máxima estimulación para Chtg (45%), Tg (38%) y Li (23%) por sobre los valores controles, no modificándose la Am. Todos los valores enzimáticos cayeron por debajo de los controles a los 60 y 80 minutos. La incorporación 3H-F fue máxima a los 40 m decayendo a tiempos más prolongados. En el presente trabajo demostramos que la administración intraduodenal de ácido oleico genera un aumento no paralelo en el nivel intrapancreático de algunas enzimas exportables, y que dichos valores caen a partir de los 40 m post-instilación, siendo la síntesis proteica afectada de manera similar