Genome-wide effects of the maternal embryonic leucine zipper kinase (MELK) in triple-negative breast cancer cells indicate context-dependent effects and p53 as a key determinant
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PROVIDER: PRJNA283397 | ENA |
REPOSITORIES: ENA
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Project description:Here, we provide evidence for the immunomodulatory effects of glucocorticoid-induced leucine zipper (GILZ) overexpression in macrophages, demonstrating enhanced antibacterial activity, protection from pyroptosis, and altered mitochondrial function. Additionally, our findings reveal a significant impact on MMP activity, suggesting a role for GILZ in influencing extracellular matrix remodeling and wound healing processes. The study contributes to explorations of GILZ in its significance in pro-resolving macrophage functions.
2024-05-13 | GSE254137 | GEO
Project description:Purpose: Gene expression analyses comparing tumors of different behaviors have been used for the identification of genes that have a role in the growth and maintenance of tumors, with the aim of both understanding the molecular basis of tumorigenesis and identifying novel potential therapeutic targets. We have here used this approach to identify the underlying gene expression differences between highly invasive glioblastoma multiforme and typically benign pilocytic astrocytomas. Experimental Design: We performed cDNA microarray analyses comparing astrocytomas of polar grade: grade I, pilocytic astrocytoma (PA), the non-invasive and most frequent pediatric tumor, with grade IV, the highly infiltrative glioblastoma multiforme (GBM) Results: Despite the significant clinical and pathological differences between the two tumor types, only 63 genes were found to exhibit two-fold or greater over-expression in GBM as compared with PA. A functional classification of the GBM over-expressed genes indicated that more than 50% are related to the regulation of the cell cycle and mitosis. Microarray data was validated by RQ-PCR testing six over-expressed genes in GBM related to PA: MELK, AUKB, ASPM, PRC1, IL13RA2 and KIAA0101. The differential expression was confirmed for all six genes, showing at least a 5 fold increase in the average expression levels in GBM compared to PA. Of the over expressed genes, that which exhibited the most statistically significant difference is Maternal Embryonic Leucine zipper Kinase (MELK). We undertook a more detailed investigation of the expression of this serine/threonine kinase gene in astrocytomas in the light of its role in the regulation of multipotent neural progenitor proliferation and previous suggestions that this may be a oncogenic target of general importance. In an examination of more than 100 tumors of the central nervous system we found progressively higher expression of MELK in GBM with astrocytoma grade and a noteworthy uniformity of high level expression in GBM. This latter feature probably explains the lack of observed association of MELK expression with survival of GBM patients. Over-expression at a similar level to GBM was also observed in medulloblastoma. We found neither gene methylation nor amplification to be a factor in MELK expression but were able to demonstrate that MELK knockdown in malignant astrocytoma cell lines caused a reduction in proliferation and anchorage-independent growth in in vitro assays. Conclusions: Our results indicate that GBM and PA differ by the expression of surprisingly few genes. Among them, MELK may play a key role in differentiating these two tumor types and represent an important therapeutic target for the management of the most frequent brain tumors in adult and children. Keywords: Comparizon of CNS tumors of different grades.
2008-03-10 | GSE7330 | GEO
Project description:Immunomodulatory effects of glucocorticoid-induced leucine zipper (GILZ) expression in murine bone-marrow derived macrophages.
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Project description:Most transcription factors possess at least one long intrinsically disordered transactivation domain that binds to a variety of co-activators and co-repressors and plays a key role in modulating the transcriptional activity. Despite the crucial importance of these mechanisms, the structural and functional basis of transactivation domain in yet poorly understood. Here, we focused on ATF4/CREB-2, an essential transcription factor for cellular stress adaptation. We found that the N-terminal region of the transactivation domain is involved in transient long-range interactions with the basic-leucine zipper domain. In vitro phosphorylation assays with the protein kinase CK2 show that the presence of the basic-leucine zipper domain is required for optimal phosphorylation of the transactivation domain. This study uncovers the intricate coupling existing between the transactivation and basic-leucine zipper domains of ATF4 and highlights its potential functional relevance.
2023-03-11 | PXD029704 | Pride
Project description:Deep mutational scanning of the interaction of JUN's leucine zipper domain and other human bZIPs in different experimental conditions
2023-10-18 | GSE245485 | GEO
Project description:Identification of Glucocorticoid-Induced Leucine Zipper (Gilz) gene targets in undifferentiated spermatogonia
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Project description:Maternal Embryonic Leucine Zipper Kinase (MELK), a Ser/Thr protein kinase, is highly over expressed in stem and cancer cells. The oncogenic role of MELK is attributed to its capacity to disable critical cell cycle checkpoints and to enhance replication. Most functional studies have relied on the use of siRNA/shRNA-mediated gene silencing, but this is often compromised by off target effects. Here we present the cellular validation of a novel, potent and selective small molecule MELK inhibitor, MELK-T1, which has enabled us to explore the biological function of MELK. Strikingly, the binding of MELK-T1 to endogenous MELK triggers a rapid and proteasome dependent degradation of the MELK protein. Treatment of MCF-7 breast adenocarcinoma cells with MELK-T1 leads to an accumulation of stalled replication forks and double strand breaks, followed by a replicative senescence phenotype. This phenotype correlates with a rapid and long-lasting ATM activation and phosphorylation of CHK2. Furthermore, MELK-T1 induces strong phosphorylation of p53 and prolonged up-regulation of p21. Our data generated with MELK-T1 indicate that MELK is a key stimulator of proliferation by its ability to increase the threshold for DNA damage tolerance. Thus, targeting MELK by combined inhibition of its catalytic function and inhibitor-induced degradation might sensitize tumors to DNA-damaging agents or radiation therapy, by lowering the DNA damage threshold.
2015-12-11 | GSE62477 | GEO
Project description:Leucine zipper-based sorting system enables generation of multi-functional CAR T cells
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Project description:The AMV v-Myb oncoprotein causes oncogenic transformation of myelomonocytic cells in vivo and in vitro. Its transforming capacity is strictly dependent upon the N-terminal DNA binding domain, the central transactivation region, and on the C-terminal domain containing a putative leucine zipper motif. While deletions in the central part of the leucine zipper region or point mutations of critical leucine residues abolish the leukemogenicity of the protein, a small deletion within the N-terminal part (deltaP mutant) preserves almost full in vitro transforming ability and only weakens the leukemogenic potential in vivo. We analyzed the gene expression profiles of ex vivo cultures transformed with either wild type or deltaP mutant of v-Myb. A few tens of genes were found to be significantly and reproducibly differentially expressed between the two cultures. Among them, the transcript of the CDKN2A gene, which is critically involved in the cell cycle progression regulation, showed higher expression in the deltaP mutant transformed cells. In mammals and also some avian species, there are two different mRNAs - ARF and INK4A – transcribed from the CDKN2A locus. It is known that in chickens the locus had been rearranged in evolution and only one mRNA is transcribed. We found that this mRNA encodes both ARF and INK4A and that the INK4A protein translation starts with a GUG codon downstream of the ARF AUG initiation codon and proceeds in a different reading frame. INK4A protein thus exists in chicken cells as well and its negative regulation by v-Myb is a part of the leukemic transformation mechanism. Comparison of expression profiles of chicken monoblasts transformed either by wild type v-myb or its mutated version designated deltaP. Three biological replicates were analyzed for each group.
2012-04-11 | E-GEOD-35413 | biostudies-arrayexpress
Project description:Melanoma accounts for over 80% of skin cancer-related deaths and current therapies provide only short-term benefit to patients. Here, we show in melanoma cells that maternal embryonic leucine zipper kinase (MELK) is transcriptionally upregulated by the MAP kinase pathway via transcription factor E2F1. MELK knockdown or pharmacological inhibition blocked melanoma growth and enhanced the effectiveness of BRAFV600E inhibitor against melanoma cells. To identify mediators of MELK function, we performed stable isotope labeling with amino acids in cell culture (SILAC) and identified 469 proteins that had downregulated phosphorylation after MELK inhibition. Remarkably, 139 of these proteins were previously reported as substrates of BRAF or MEK, demonstrating that MELK is an important downstream mediator of the MAPK pathway. Furthermore, we show that MELK promotes melanoma growth by activating NF-B pathway activity via Sequestosome 1 (SQSTM1/p62). Collectively, these results underpin an important role for MELK in melanoma growth, downstream of the MAPK pathway.
2017-12-07 | PXD007872 | Pride