bioRxiv Science⌕ Search

Biology subjects

Mougiakakos, D.

Publications and source records attributed to Mougiakakos, D..

3 recordsLinked to original sources

Unveiling the signaling network of FLT3-ITD AML improves drug sensitivity prediction

Currently, the identification of patient-specific therapies in cancer is mainly informed by personalized genomic analysis. In the setting of acute myeloid leukemia (AML), patient-drug treatment matching fails in a subset of patients harboring atypical internal tandem duplications (ITDs) in the tyrosine kinase domain of the FLT3 gene. To address this unmet medical need, here we develop a systems-based strategy that integrates multiparametric analysis of crucial signaling pathways, and patient-specific genomic and transcriptomic data with a prior-knowledge signaling network using a Boolean-based formalism. By this approach, we derive personalized predictive models describing the signaling landscape of AML FLT3-ITD positive cell lines and patients. These models enable us to derive mechanistic insight into drug resistance mechanisms and suggest novel opportunities for combinatorial treatments. Interestingly, our analysis reveals that the JNK kinase pathway plays a crucial role in the tyrosine kinase inhibitor response of FLT3-ITD cells through cell cycle regulation. Finally, our work shows that patient-specific logic models have the potential to inform precision medicine approaches.

cancer biology↗

A key role of the WEE1-CDK1 axis in mediating TKI-therapy resistance in FLT3-ITD positive acute myeloid leukemia patients

Internal tandem duplications (ITDs) in the FLT3 gene are frequently identified and confer a poor prognosis in patient affected by acute myeloid leukemia (AML). The insertion site of the ITDs in FLT3 significantly impacts the sensitivity to tyrosine kinase inhibitors (TKIs) therapy, affecting patients clinical outcome. To decipher the molecular mechanisms driving the different sensitivity to TKIs therapy of FLT3-ITD mutation, we used high-sensitive mass spectrometry-based (phospho)proteomics and deep sequencing. Here, we present a novel generally-applicable strategy that supports the integration of unbiased large-scale datasets with literature-derived signaling networks. The approach produced FLT3-ITDs specific predictive models and revealed a crucial and conserved role of the WEE1-CDK1 axis in TKIs resistance. Remarkably, we found that pharmacological inhibition of the WEE1 kinase synergizes and strengthens the pro-apoptotic effect of TKIs therapy in cell lines and patient-derived primary blasts. In conclusion, this work proposes a new molecular mechanism of TKIs resistance in AML and suggests a combination therapy as option to improve therapeutic efficacy.

cancer biology↗

Mitochondrial function is essential for humoral immunity by controlling flux of the TCA cycle, phosphatidic acid and mTOR activity in B cells

The function of mitochondrial respiration during B cell fate decisions and differentiation remains equivocal. This study reveals that selection for mitochondrial fitness occurs during B cell activation and is essential for subsequent plasma cell differentiation. By expressing a mutated mitochondrial helicase in transitional B cells, we depleted mitochondrial DNA during B cell maturation, resulting in reduced oxidative phosphorylation. Although no changes in follicular B cell development were evident, germinal centers, class switch recombination to IgG, plasma cell generation and humoral immunity were diminished. Defective oxidative phosphorylation led to aberrant flux of the tricarboxylic acid cycle and lowered the amount of saturated phosphatidic acid. Consequently, MTOR activity and BLIMP-1 induction were curtailed whereas HIF1, glycolysis and AMPK activity were amplified. Exogenous phosphatidic acid increased mTOR activity in activated B cells. Hence, mitochondrial function is required and selected for in activated B cells for the successful generation of functional plasma cells.

immunology↗