Evi1 Counteracts Anti-Leukemic and Stem Cell Inhibitory Effects of All-Trans Retinoic Acid on Flt3-ITD/Npm1c-Driven Acute Myeloid Leukemia Cells.

All-trans retinoic acid (atRA) has a dramatic impact on the survival of patients with acute promyelocytic leukemia, but its therapeutic value in other types of acute myeloid leukemia (AML) has so far remained unclear. Given that AML is a stem cell-driven disease, recent studies have addressed the effects of atRA on leukemic stem cells (LSCs). atRA promoted stemness of MLL-AF9-driven AML in an Evi1-dependent manner but had the opposite effect in Flt3-ITD/Nup98-Hoxd13-driven AML. Overexpression of the stem cell-associated transcription factor EVI1 predicts a poor prognosis in AML, and is observed in different genetic subtypes, including cytogenetically normal AML. Here, we therefore investigated the effects of Evi1 in a mouse model for cytogenetically normal AML, which rests on the combined activity of Flt3-ITD and Npm1c mutations. Experimental expression of Evi1 on this background strongly promoted disease aggressiveness. atRA inhibited leukemia cell viability and stem cell-related properties, and these effects were counteracted by overexpression of Evi1. These data further underscore the complexity of the responsiveness of AML LSCs to atRA and point out the need for additional investigations which may lay a foundation for a precision medicine-based use of retinoids in AML

SOCS2 is part of a highly prognostic 4-gene signature in AML and promotes disease aggressiveness.

Acute myeloid leukemia (AML) is a heterogeneous disease with respect to its genetic and molecular basis and to patients´ outcome. Clinical, cytogenetic, and mutational data are used to classify patients into risk groups with different survival, however, within-group heterogeneity is still an issue. Here, we used a robust likelihood-based survival modeling approach and publicly available gene expression data to identify a minimal number of genes whose combined expression values were prognostic of overall survival. The resulting gene expression signature (4-GES) consisted of 4 genes (SOCS2, IL2RA, NPDC1, PHGDH), predicted patient survival as an independent prognostic parameter in several cohorts of AML patients (total, 1272 patients), and further refined prognostication based on the European Leukemia Net classification. An oncogenic role of the top scoring gene in this signature, SOCS2, was investigated using MLL-AF9 and Flt3-ITD/NPM1c driven mouse models of AML. SOCS2 promoted leukemogenesis as well as the abundance, quiescence, and activity of AML stem cells. Overall, the 4-GES represents a highly discriminating prognostic parameter in AML, whose clinical applicability is greatly enhanced by its small number of genes. The newly established role of SOCS2 in leukemia aggressiveness and stemness raises the possibility that the signature might even be exploitable therapeutically

SOCS2 is part of a highly prognostic 4-gene signature in AML and promotes disease aggressiveness

Acute myeloid leukemia (AML) is a heterogeneous disease with respect to its genetic and molecular basis and to patients´ outcome. Clinical, cytogenetic, and mutational data are used to classify patients into risk groups with different survival, however, within-group heterogeneity is still an issue. Here, we used a robust likelihood-based survival modeling approach and publicly available gene expression data to identify a minimal number of genes whose combined expression values were prognostic of overall survival. The resulting gene expression signature (4-GES) consisted of 4 genes (SOCS2, IL2RA, NPDC1, PHGDH), predicted patient survival as an independent prognostic parameter in several cohorts of AML patients (total, 1272 patients), and further refined prognostication based on the European Leukemia Net classification. An oncogenic role of the top scoring gene in this signature, SOCS2, was investigated using MLL-AF9 and Flt3-ITD/NPM1c driven mouse models of AML. SOCS2 promoted leukemogenesis as well as the abundance, quiescence, and activity of AML stem cells. Overall, the 4-GES represents a highly discriminating prognostic parameter in AML, whose clinical applicability is greatly enhanced by its small number of genes. The newly established role of SOCS2 in leukemia aggressiveness and stemness raises the possibility that the signature might even be exploitable therapeutically

DNA methylation transcriptionally regulates the putative tumor cell growth suppressor ZNF677 in non-small cell lung cancers

In our study, we investigated the role of ZNF677 in non-small cell lung cancers (NSCLC). By comparing ZNF677 expression in primary tumor (TU) and in the majority of cases also of corresponding non-malignant lung tissue (NL) samples from > 1,000 NSCLC patients, we found tumor-specific downregulation of ZNF677 expression (adjusted p-values < 0.001). We identified methylation as main mechanism for ZNF677 downregulation in NSCLC cells and we observed tumor-specific ZNF677 methylation in NSCLC patients (p < 0.0001). In the majority of TUs, ZNF677 methylation was associated with loss of ZNF677 expression. Moreover, ZNF677 overexpression in NSCLC cells was associated with reduced cell proliferation and cell migration. ZNF677 was identified to regulate expression of many genes mainly involved in growth hormone regulation and interferon signalling. Finally, patients with ZNF677 methylated TUs had a shorter overall survival compared to patients with ZNF677 not methylated TUs (p = 0.013). Overall, our results demonstrate that ZNF677 is trancriptionally regulated by methylation in NSCLCs, suggest that ZNF677 has tumor cell growth suppressing properties in NSCLCs and that ZNF677 methylation might serve as prognostic parameter in these patients

IDO1 + Paneth cells promote immune escape of colorectal cancer

Abstract: Tumors have evolved mechanisms to escape anti-tumor immunosurveillance. They limit humoral and cellular immune activities in the stroma and render tumors resistant to immunotherapy. Sensitizing tumor cells to immune attack is an important strategy to revert immunosuppression. However, the underlying mechanisms of immune escape are still poorly understood. Here we discover Indoleamine-2,3-dioxygenase-1 (IDO1)+ Paneth cells in the stem cell niche of intestinal crypts and tumors, which promoted immune escape of colorectal cancer (CRC). Ido1 expression in Paneth cells was strictly Stat1 dependent. Loss of IDO1+ Paneth cells in murine intestinal adenomas with tumor cell-specific Stat1 deletion had profound effects on the intratumoral immune cell composition. Patient samples and TCGA expression data suggested corresponding cells in human colorectal tumors. Thus, our data uncovered an immune escape mechanism of CRC and identify IDO1+ Paneth cells as a target for immunotherapy

IDO1 + Paneth cells promote immune escape of colorectal cancer

Abstract: Tumors have evolved mechanisms to escape anti-tumor immunosurveillance. They limit humoral and cellular immune activities in the stroma and render tumors resistant to immunotherapy. Sensitizing tumor cells to immune attack is an important strategy to revert immunosuppression. However, the underlying mechanisms of immune escape are still poorly understood. Here we discover Indoleamine-2,3-dioxygenase-1 (IDO1)+ Paneth cells in the stem cell niche of intestinal crypts and tumors, which promoted immune escape of colorectal cancer (CRC). Ido1 expression in Paneth cells was strictly Stat1 dependent. Loss of IDO1+ Paneth cells in murine intestinal adenomas with tumor cell-specific Stat1 deletion had profound effects on the intratumoral immune cell composition. Patient samples and TCGA expression data suggested corresponding cells in human colorectal tumors. Thus, our data uncovered an immune escape mechanism of CRC and identify IDO1+ Paneth cells as a target for immunotherapy

The role of eukaryotic initiation factors in colorectal cancer

Hintergrund: Darmkrebs ist mit einer weltweiten Inzidenz von 1 Million Neuerkrankungen pro Jahr die dritthäufigste Krebserkrankung. Das kolorektale Karzinom (CRC) macht dabei 95% der bösartigen Darmtumore aus. Eine Vielzahl von genetischen und epigenetischen Veränderungen sind an der Pathogenese dieser Erkrankung beteiligt. Es gibt Hinweise, dass dabei auch eukaryotische Initiationsfaktoren (eIFs) eine Rolle spielen. Ziel dieser Arbeit war es, mehr Wissen über molekulare Veränderungen von eIFs beim CRC zu erlangen. Methoden: Expressionsdaten von eIFs wurden aus folgenden Quellen erhoben: (a) immunhistochemische Bestimmung der Proteinexpression mehrerer eIFs mittels tissue microarray Analysen von primären CRCs und von korrespondierenden nicht-malignen Kontrollproben und (b) RNA-seq Daten von >350 CRC PatientInnen aus der TCGA Datenbank. Außerdem wurden von diesen PatientInnen Daten bezüglich eIF copy number alterations (CNV), Mutationen und DNA Methylierung analysiert. Gruppenvergleiche, Clusteranalysen, Korrelationsanalysen und Überlebensanalysen wurden durchgeführt. Ergebnisse: Die Proteinexpression von 10 eIFs (eIF1, eIF2A, eIF3_p110, eIF3B, eIF3H, eIF3Q, eIF3M, eIF4E, eIF4G und eIF6) wurde immunhistochemisch bei 25 CRC PatientInnen untersucht. Dabei wurden mehrere tumor-spezifisch hinauf- (eIF3B, eIF3Q und eIF1) bzw. hinunterregulierte (eIF4E) eIFs identifiziert. Clusteranalysen von RNA-seq Daten haben gezeigt, dass sich das Expressionmuster von eIFs in primären CRCs stark vom eIF Expressionsmuster in nicht-malignen Kontrollproben unterscheidet. Die Frequenz von eIF CNVs in primären CRCs war in den meisten Fällen niedrig und Mutationen in kodierenden Regionen von eIF Genen wurden keine gefunden. Diese genetischen Veränderungen scheinen daher nicht oder nur teilweise für das veränderte Expressionsmuster von eIFs in primären CRCs verantwortlich zu sein. Es wurde eine negative Korrelation zwischen der EIF2S2 bzw. EIF6 Expression und der Methylierung dieser Gene in den primären CRCs beobachtet. Die Expression dieser eIFs scheint daher epigenetisch reguliert zu sein. Ein Vergleich der eIF mRNA Expression und bestimmten klinisch-pathologischen Parametern der CRC PatientInnen ergab einen Zusammenhang von der eIF Deregulation mit dem Krankheitsstadium und dem Mikrosatelliten Status der PatientInnen. Außerdem könnte die Expression bestimmter eIFs prognostisch relevant sein. Conclusio: Insgesamt zeigen unsere Daten, dass eIFs in der Pathogenese des CRC differentiell exprimiert sind und dass genetische Veränderungen von eIFs nur vereinzelt auftreten. Weitere Studien sind nötig um die Rolle von eIFs beim CRC besser zu definieren.Background: Colorectal cancer (CRC) belongs to the most frequently occurring cancer types in the world. A large number of genetic and epigenetic defects are known which are involved in the pathogenesis of this disease. There is evidence that eukaryotic translation initiation factors may play a role in human cancers, including CRC. However, knowledge about genetic and epigenetic abnormalities of eIFs in CRCs is limited. The major goal of the presented thesis was to get a deeper insight into the role of eIFs in CRCs. Methods: Two sources for eIF expression data were available: (a) immunohistochemistry data from tissue microarrays of primary CRCs and matching non-malignant controls and (b) RNA-seq data of >350 CRC patients from TCGA. In addition, data about copy number alterations (CNV), mutations and DNA methylation of the same CRC cases were available. Group statistics, cluster analyses, correlation analyses and survival analyses were performed. Results: Protein expression of 10 eIFs (eIF1, eIF2A, eIF3_p110, eIF3B, eIF3H, eIF3Q, eIF3M, eIF4E, eIF4G and eIF6) was analyzed immunohistochemically in 25 CRC patients. Several eIFs were found to be tumor-specifically up- (eIF3B, eIF3Q and eIF1) or downregulated (eIF4E) in these patients. Hierarchical clustering and principal component analyses of primary CRC and non-malignant control samples based on mRNA expression of eIFs resulted in a clear separation of these two tissue types suggesting that eIFs are deregulated in CRC. Only a low frequency of eIF CNVs was observed and mutations in eIF encoding genes were absent in primary CRCs. A negative correlation between EIF2S2 or EIF6 expression and methylation of these genes was found indicating that expression of these 2 genes may be regulated by methylation in CRCs. Comparison of eIF mRNA expression with certain clinico-pathological characteristics of the CRC patients revealed associations between certain of these genes with disease stage and microsatellite instability status. Moreover, expression of some factors may be of prognostic relevance for CRC patients. Conclusion: Overall, our data demonstrate that differential expression of eIFs but not genetic alterations of them may play a role in the pathogenesis of CRC, however, additional studies are necessary to prove this concept.Vorgelegt von: Gerwin HellerWien, FH Campus Wien, Masterarb., 2017(VLID)200178

Evi1 Counteracts Anti-Leukemic and Stem Cell Inhibitory Effects of All-Trans Retinoic Acid on Flt3-ITD/Npm1c-Driven Acute Myeloid Leukemia Cells.

All-trans retinoic acid (atRA) has a dramatic impact on the survival of patients with acute promyelocytic leukemia, but its therapeutic value in other types of acute myeloid leukemia (AML) has so far remained unclear. Given that AML is a stem cell-driven disease, recent studies have addressed the effects of atRA on leukemic stem cells (LSCs). atRA promoted stemness of MLL-AF9-driven AML in an Evi1-dependent manner but had the opposite effect in Flt3-ITD/Nup98-Hoxd13-driven AML. Overexpression of the stem cell-associated transcription factor EVI1 predicts a poor prognosis in AML, and is observed in different genetic subtypes, including cytogenetically normal AML. Here, we therefore investigated the effects of Evi1 in a mouse model for cytogenetically normal AML, which rests on the combined activity of Flt3-ITD and Npm1c mutations. Experimental expression of Evi1 on this background strongly promoted disease aggressiveness. atRA inhibited leukemia cell viability and stem cell-related properties, and these effects were counteracted by overexpression of Evi1. These data further underscore the complexity of the responsiveness of AML LSCs to atRA and point out the need for additional investigations which may lay a foundation for a precision medicine-based use of retinoids in AML