CXCR4 Signaling Has a CXCL12-Independent Essential Role in Murine MLL-AF9-Driven Acute Myeloid Leukemia
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE135275 | GEO | 2019/11/15
REPOSITORIES: GEO
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Project description:T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy characterized by infiltration of the bone marrow and other sites with transformed T cell progenitors. The role of tissue microenvironments in the pathogenesis of T-ALL or any other type of acute leukemia is little understood. In delineating interactions between T-ALL cells and their environment, we initially found that T-ALL cells express high surface levels of the chemokine receptor CXCR4. Intravital imaging of an intact tibia revealed T-ALL cells in direct contact with bone marrow stromal cells producing the CXCR4 ligand, CXCL12. Genetic targeting of CXCR4 on T-ALL cells resulted in a marked reduction of leukemia burden and prolonged disease remission, and disruption of the CXCL12/CXCR4 axis using small molecule inhibitors prevented T-ALL progression in a primary xenograft model. Finally, we were able to show that CXCR4 inhibition significantly decreased expression of Myc and its target genes. Myc expression is a key regulator of T-ALL leukemia initiating cell (LIC) activity, suggesting that CXCR4 inhibition can suppress LIC activity by silencing the Myc response in T-ALL cells. Our data suggest that targeting of CXCL12/CXCR4 signaling could be a powerful new tool for combating T-ALL, a disease with no current targeted therapies. Mouse T-ALL cells were treated ex vivo with Cxcr4 inhibitor AMD3100 or vehicle control. Additionally, mouse T-ALL primary tumors were isolated from control (Cxcr4+/+) or knockout (Cxcr4-/-) animals. Total RNA was extracted from samples using the RNeasy Plus Mini Kit (Qiagen). Samples were then subject to PolyA selection using oligo-dT beads (Life Technologies, Carlsbad, CA) according to the manufacturer's instructions. The resulting RNA samples were then used as input for library construction using the dUTP method as described by Parkhomchuck et al., 2009. RNA libraries were then sequenced on the Illumina HiSeq 2500 using 50bp single-end reads.
2015-08-12 | E-GEOD-60367 | biostudies-arrayexpress
Project description:T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy characterized by infiltration of the bone marrow and other sites with transformed T cell progenitors. The role of tissue microenvironments in the pathogenesis of T-ALL or any other type of acute leukemia is little understood. In delineating interactions between T-ALL cells and their environment, we initially found that T-ALL cells express high surface levels of the chemokine receptor CXCR4. Intravital imaging of an intact tibia revealed T-ALL cells in direct contact with bone marrow stromal cells producing the CXCR4 ligand, CXCL12. Genetic targeting of CXCR4 on T-ALL cells resulted in a marked reduction of leukemia burden and prolonged disease remission, and disruption of the CXCL12/CXCR4 axis using small molecule inhibitors prevented T-ALL progression in a primary xenograft model. Finally, we were able to show that CXCR4 inhibition significantly decreased expression of Myc and its target genes. Myc expression is a key regulator of T-ALL leukemia initiating cell (LIC) activity, suggesting that CXCR4 inhibition can suppress LIC activity by silencing the Myc response in T-ALL cells. Our data suggest that targeting of CXCL12/CXCR4 signaling could be a powerful new tool for combating T-ALL, a disease with no current targeted therapies.
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Project description:Fms-like tyrosine kinase 3 (Flt3) tyrosine kinase inhibitors (Flt3-TKI) have improved outcomes for patients with Flt3-mutated acute myeloid leukemia (AML) but are limited by resistance and relapse, suggesting persistence of leukemia stem cells (LSC). Here we utilized a Flt3-internal tandem duplication (Flt3-ITD) and Tet2-deleted AML genetic mouse model to characterize Flt3-ITD AML LSC and their resistance to Flt3-TKI. We show that LSC were enriched within the primitive ST-HSC population. CXCl12-expressing osteoprogenitors were increased in the Flt3-ITD AML marrow and FLT3-ITD LSC showed increased expression of the CXCL12 receptor CXCR4. CXCL12 deletion from the microenvironment enhanced AML targeting by combined Flt3-TKI and chemotherapy treatment with enhanced LSC targeting. We found that both treatment and CXCL12 deletion partially reduced p38 mitogen-activated protein kinase (p38) signaling with increased, but not complete, reduction seen with combined treatment and CXCL12 deletion. Our studies suggest that p38 contributes to CXCL12-mediated maintenance of AML LSC following Flt3-TKI and chemotherapy treatment, but that p38 inhibition enhances AML LSC response to treatment to a greater extent than CXCL12 deletion alone. This study supports a role for p38 signaling in CXCL12-mediated protection of AML LSC from treatment and provide a rationale for targeting p38 signaling to enhance Flt3-ITD AML targeting.
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Project description:Surface expression of C-X-C chemokine receptor type 4 (CXCR4) in acute myeloid leukemia (AML) has been reported to be an independent prognostic factor for disease relapse and survival. We previously reported that targeting the stromal-derived factor 1M-NM-1 (SDF-1M-NM-1)/CXCR4 axis could overcome resistance of AML cells to chemotherapy both in vitro and in vivo. To further explore the mechanism of targeting CXCR4, in the current study we focused on the regulation of microRNA. Microarray analysis revealed that the hsa-let-7a microRNA was down-regulated in OCI-AML3 cells by SDF-1M-NM-1 treatment and increased after CXCR4 inhibition. To further investigate the role of hsa-let-7a in leukemia biology, we overexpressed it in AML cell lines, which resulted in decreased Bcl-xL protein expression and consequently enhanced cell sensitivity to the chemotherapeutic agent cytarabine, both in vitro and in vivo. We also identified the transcription factor Yin Yang 1 (YY1) as a mediator that links the SDF-1M-NM-1/CXCR4 axis with hsa-let-7a. Western blotting and immunocytochemistry demonstrated a correlation between YY1 and CXCR4 activation. ChIP assay confirmed the binding of YY1 to pri-let-7a DNA fragments. In primary AML samples (n=50), high CXCR4 surface expression was associated with low hsa-let-7a levels (r2=0.53). Improved effects of cytarabine treatment associated with greatly extended survival of human AML carrying mice was observed in primary human AML overexpressing hsa-let-7a. On the basis of these results, we propose that CXCR4 regulation of hsa-let-7a microRNA through YY1 and transcriptional silencing of the Bcl-xL protein together identifies a novel mechanism by which CXCR4 functions to induce chemoresistance in AML cells. MicroRNA expression profiling of OCI-AML3 cell lines treated with CXCR4 antagonist or SDF-1M-NM-1. OCI-AML3 cells were treated with 100 ng/mL SDF-1M-NM-1 or 250 nM POL6326 (a CXCR4 antagonist, Allschwil, Switzerland), total RNA was extracted at specific time points (1, 2, 4, and 8 h), and miRNA expression profiling was performed
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Project description:The chemokine CXCL12 and its receptor CXCR4 play important roles in signaling and migration of T-cells, but little is known about the transcriptional events involved in CXCL12-mediated T-cell migration. In this study we performed microarray analysis on CXCL12- treated T-cells, and found that the Wnt family of proteins was significantly upregulated during CXCL12 treatment. Confirmation of these results by real-time PCR and Western analysis indicated that the non-canonical Wnt pathway was specifically upregulated during CXCL12 treatment. In vitro and in vivo knockdown studies confirm that b-catenin (the key mediator of canonical Wnt signaling) is not involved in the CXCL12-mediated migration of T-cells. However, Wnt5A, a non-canonical Wnt protein, increases signaling through the CXCL12/ CXCR4 axis via Protein Kinase C (PKC). Our results demonstrated that CXCL12 required Wnt5A to mediate T-cell migration, and the treatment of T-cells with recombinant Wnt5A sensitized T-cells to CXCL12 induced migration. Additionally, Wnt5A expression was required for the sustained expression of CXCR4, both transcriptionally and translationally. These results could be translated in vivo, using EL4 thymoma metastasis as a model of T-cell migration. Taken together our data indicate, for the first time, that Wnt5A is a critical mediator of the CXCL12/ CXCR4 signaling axis. Keywords: Wnt5A, CXCL12, CXCL12, CXCR4, T-cell Migration
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Project description:Surface expression of C-X-C chemokine receptor type 4 (CXCR4) in acute myeloid leukemia (AML) has been reported to be an independent prognostic factor for disease relapse and survival. We previously reported that targeting the stromal-derived factor 1α (SDF-1α)/CXCR4 axis could overcome resistance of AML cells to chemotherapy both in vitro and in vivo. To further explore the mechanism of targeting CXCR4, in the current study we focused on the regulation of microRNA. Microarray analysis revealed that the hsa-let-7a microRNA was down-regulated in OCI-AML3 cells by SDF-1α treatment and increased after CXCR4 inhibition. To further investigate the role of hsa-let-7a in leukemia biology, we overexpressed it in AML cell lines, which resulted in decreased Bcl-xL protein expression and consequently enhanced cell sensitivity to the chemotherapeutic agent cytarabine, both in vitro and in vivo. We also identified the transcription factor Yin Yang 1 (YY1) as a mediator that links the SDF-1α/CXCR4 axis with hsa-let-7a. Western blotting and immunocytochemistry demonstrated a correlation between YY1 and CXCR4 activation. ChIP assay confirmed the binding of YY1 to pri-let-7a DNA fragments. In primary AML samples (n=50), high CXCR4 surface expression was associated with low hsa-let-7a levels (r2=0.53). Improved effects of cytarabine treatment associated with greatly extended survival of human AML carrying mice was observed in primary human AML overexpressing hsa-let-7a. On the basis of these results, we propose that CXCR4 regulation of hsa-let-7a microRNA through YY1 and transcriptional silencing of the Bcl-xL protein together identifies a novel mechanism by which CXCR4 functions to induce chemoresistance in AML cells.
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Project description:Extramedullary infiltration (EMI) is a concomitant manifestation indicating poor prognosis of acute myeloid leukemia (AML), yet the underlying mechanism remains poorly understood and therapeutic options are limited. Here, we employed single-cell RNA sequencing on bone marrow (BM) and EMI samples from an AML patient presenting pervasive leukemia cutis. A complement C1Q + macrophage-like leukemia subset which is enriched within cutis and existed in BM prior to EMI manifestations was identified and further verified in multiple AML patients. RNA-sequencing and quantitative proteomics profiling revealed adverse prognosis of patients bearing C1Q + population. C1Q expression endowed leukemia cells with tissue-infiltration ability which could establish prominent cutaneous or gastrointestinal EMI nodules in patient-derived xenograft (PDX) and CDX models. Fibroblasts attracted migration of the C1Q + leukemia cells through surface C1Q-gC1QR recognition and subsequent stimulation of MAFB-TGF-β signaling. Thus, C1Q orchestrates cancer infiltration pathways through communicating with fibroblasts and represents a compelling therapeutic target for EMI.
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2010-07-14 | E-GEOD-22925 | biostudies-arrayexpress