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

Investigation of the effect of the calcitonin gene-related peptide (CGRP) on the resistance of acute myeloid leukemia cell lines to daunorubicin and cytosine arabinoside

Akute myeloische Leukämie (AML) ist eine hämatopoetische Erkrankung, die durch klonale Expansion und Akkumulation funktionell beeinträchtigter hämatopoetischer Stamm- und Vorläuferzellen im Knochenmark, und oft auch im peripheren Blut, verursacht wird. Im Jahr 2018 traten in den Vereinigten Staaten etwa 19.520 neue AML Fälle auf und etwa halb so viele Personen verstarben an AML. Vollständige Remission wird in 50 % bis 80 % der Fälle nach einer zytotoxischen Behandlung mit Cytarabin (araC) und einem Anthracyclin-Antibiotikum (z. B. Daunorubicin) erreicht. Durch Persistenz oder Wiederauftreten der Krankheit stirbt jedoch ein Großteil der Patienten. Es wurden mehrere Modelle vorgeschlagen, um die Therapieresistenz zu erklären, die zu einem Rezidiv führt; eines davon nimmt an, dass während der Chemotherapie neu erworbene oder durch diese selektierte molekulare Veränderungen zu dieser Resistenz beitragen. Frühere Experimente, die in unserer Arbeitsgruppe durchgeführt wurden, haben zur Identifizierung von Genen geführt, die signifikant unterschiedlich zwischen dem Zeitpunkt der Diagnose und dem Rezidiv von AML exprimiert wurden. Unter ihnen befand sich das Gen Calcitonin Receptor Like Receptor (CALCRL). Es kodiert für einen G-Protein-gekoppelten Rezeptor mit sieben Transmembrandomänen. Einer seiner Hauptliganden ist das Calcitionin Gene-Related Peptide (CGRP). Vorläufige Daten der Arbeitsgruppe wiesen darauf hin, dass der CGRP-Signalweg über CALCRL an der Förderung des Überlebens von AML-Zellen unter einer zytotoxischen Behandlung beteiligt ist. Ziel dieser Arbeit war es, CGRP und CALCRL weiter als potenzielle Ziele für rational konzipierte Behandlungen zu charakterisieren. Die Auswirkungen von CGRP auf die zelluläre Viabilität, Apoptose und Proliferation wurden untersucht, indem der Ligand zu CALCRL-positiven malignen myeloischen humanen Zelllinien hinzugefügt wurde. CGRP schützte diese Zelllinien vor Apoptose, die durch zytotoxische Behandlung (Daunorubicin und AraC) induziert wurde. Die metabolische Aktivität nach der zytotoxischen Behandlung war in Gegenwart von CGRP höher. Darüber hinaus reduzierte CGRP die Aktivität der Effektorcaspasen 3 und 7 sowie den Anteil von Zellen mit fragmentierter DNA während einer zytotoxischen Behandlung. Interessanterweise hatte CGRP keinen Einfluss auf die Proliferationsrate der Zellen. Die Verwendung von zwei Rezeptorantagonisten, dem kleinen Molekül Olcegepant und dem Peptid-Antagonisten CGRP(8-37) (ein verkürztes CGRP-Molekül, das an CALCRL bindet, diesen aber nicht aktiviert), bestätigte die Spezifität des CGRP-Effekts. Beide Antagonisten hoben die resistenzsteigernde Wirkung von CGRP auf. Schließlich führte der Knock-down von CALCRL zu einer Reduktion der protektiven Wirkung von CGRP. Zusammenfassend deuten diese Daten darauf hin, dass CGRP über seinen Rezeptor CALCRL zur Resistenz gegen Chemotherapie bei AML beiträgtAcute myeloid leukemia (AML) is a hematopoietic malignancy caused by clonal expansion and accumulation of functionally impaired hematopoietic stem and progenitor cells in the bone marrow and often also the peripheral blood. In 2018, approximately 19,520 new cases occurred in the United States and about half of that number died of AML Complete remission is achieved in 50 % to 80 % of cases following cytotoxic treatment with cytarabin (araC) and an anthracycline antibiotic (e.g., daunorubicin). Nevertheless, many patients die due to disease persistence or relapse. Several models have been put forward to explain therapy resistance that leads to, and is associated with, relapse; one of these assumes that molecular alterations newly acquired, or selected for, during chemotherapy contribute to this resistance. Previous experiments performed in the host lab have led to the identification of genes significantly differentially expressed between diagnosis and relapse of AML. Among them was the calcitonin receptor like receptor (CALCRL) gene. It encodes a G-protein coupled receptor with seven transmembrane domains; one of its main ligands is the calcitionin gene-related peptide (CGRP). Preliminary data from the host lab indicated that CGRP signaling via CALCRL is involved in promoting the survival of AML cells under cytotoxic treatment. In this investigation, I aimed to further characterize CGRP and CALCRL as potential targets for rationally designed treatments. The effects of CGRP on cellular viability, apoptosis, and proliferation were investigated by adding the ligand to CALCRL positive human malignant myeloid cell lines. CGRP protected these cell lines from apoptosis induced by cytotoxic drugs (daunorubicin and araC). Metabolic activity after drug treatment was higher in the presence of CGRP. Moreover, CGRP reduced the activity of the executioner caspases 3 and 7, as well as the proportion of cells with fragmented DNA, under cytotoxic treatment. Interestingly, CGRP had no effect on the proliferation rate of the cells. The use of two receptor antagonists, the small molecule olcegepant and the peptide antagonist CGRP(8-37) (a truncated CGRP molecule that binds, but does not activate, CALCRL), confirmed the specificity of the CGRP effect. Both antagonists abolished the resistance-increasing property of CGRP. Finally, knock-down of CALCRL led to a reduction of the protective effect of CGRP. In conclusion, these data suggest that CGRP via its receptor CALCRL contributes to chemotherapy resistance in AML

CGRP Signaling via CALCRL Increases Chemotherapy Resistance and Stem Cell Properties in Acute Myeloid Leukemia

The neuropeptide CGRP, acting through the G-protein coupled receptor CALCRL and its coreceptor RAMP1, plays a key role in migraines, which has led to the clinical development of several inhibitory compounds. Recently, high CALCRL expression has been shown to be associated with a poor prognosis in acute myeloid leukemia (AML). We investigate, therefore, the functional role of the CGRP-CALCRL axis in AML. To this end, in silico analyses, human AML cell lines, primary patient samples, and a C57BL/6-based mouse model of AML are used. We find that CALCRL is up-regulated at relapse of AML, in leukemic stem cells (LSCs) versus bulk leukemic cells, and in LSCs versus normal hematopoietic stem cells. CGRP protects receptor-positive AML cell lines and primary AML samples from apoptosis induced by cytostatic drugs used in AML therapy, and this effect is inhibited by specific antagonists. Furthermore, the CGRP antagonist olcegepant increases differentiation and reduces the leukemic burden as well as key stem cell properties in a mouse model of AML. These data provide a basis for further investigations into a possible role of CGRP-CALCRL inhibition in the therapy of AML