Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There is growing evidence that the HOX homeobox-containing transcription factors are differentially expressed during hematopoiesis. We have previously demonstrated that the HOXA10 gene is expressed in unfractionated normal marrow and in immortalized leukemic cell lines with myelomonocytic features, but not in cell lines with lymphoid or erythroid features. To gain insights into the patterns of activation of this gene during hematopoietic differentiation, we have examined HOXA10 expression in CD34+ and CD34- subfractions of normal marrow and normal peripheral blood, as well as samples from patients with a variety of acute and chronic leukemias. HOXA10 is strongly expressed in CD34+ normal marrow cells, markedly downregulated in CD34- marrow cells, and inactive in mature neutrophils, monocytes, and lymphocytes. HOXA10 is expressed in all types of acute myelogenous leukemia (AML) with the notable exception of acute promyelocytic leukemia (AML-M3). HOXA10 message is observed in chronic myelogenous leukemia (CML) but appears to be reduced in accelerated phase and blast crisis, particularly lymphoid blast crisis. With rare exception, HOXA10 expression is not observed in samples of acute or chronic lymphoid leukemias. Normal marrow and patient samples appear to contain a single transcript which encodes a full-length homeobox-containing protein, while immortalized cell lines contain an additional alternatively spliced transcript. These studies indicate that HOXA10 expression is restricted to early stages of myeloid differentiation.
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PMID:Stage- and lineage-specific expression of the HOXA10 homeobox gene in normal and leukemic hematopoietic cells. 755 25

Chronic myelogenous leukemia is characterized by the reciprocal chromosomal translocation (9;22), which generates a novel fusion gene, BCR-ABL. Bcr-Abl-expressing leukemia cells are highly resistant to apoptosis. Imatinib an Abl kinase inhibitor, is a highly effective agent for patients with CML. However, a small percentage of these patients and most advanced-phase patients relapse on imatinib therapy. It is poorly understood whether the Abl kinase inhibitors are able to eradicate CML progenitor or stem cells. In this study, we investigated the role of HOXA10 in CML cell lines and the hematopoietic progenitor cells derived from CML patients, and whether the regulation of HOXA10 eradicates Bcr-Abl(+) hematopoietic stem/progenitor cells. The Abl kinase inhibitors and PI3K inhibitor, LY294002, induced the expression of HOXA10, and it enhanced apoptosis in CML cells. Moreover, the reduction of HOXA10 expression by siRNA in CML cells inhibited apoptosis by treatment with the Abl kinase inhibitors and LY294002. These results revealed that HOXA10 had an important role in induction of apoptosis by the Abl kinase inhibitors in CML cells. Finally, we showed that the inhibition of HOXA10 expression by siRNA increased the numbers of CFU-GEMM, BFU-E, and CFU-GM when the cells were treated with the combination of BMS354825 and LY294002 compared to control cells, and HOXA10 played a critical role in the committed colony-formation in CML. This study shows for the first time that the Abl kinase inhibitor and LY294002 induced HOXA10, and HOXA10 had an important role in apoptosis or cell growth inhibition in CML cells in vitro.
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PMID:HOXA10 expression induced by Abl kinase inhibitors enhanced apoptosis through PI3K pathway in CML cells. 1819 Sep 61

Structural chromosomal rearrangements of the Nucleoporin 98 gene (NUP98), primarily balanced translocations and inversions, are associated with a wide array of hematopoietic malignancies. NUP98 is known to be fused to at least 28 different partner genes in patients with hematopoietic malignancies, including acute myeloid leukemia, chronic myeloid leukemia in blast crisis, myelodysplastic syndrome, acute lymphoblastic leukemia, and bilineage/biphenotypic leukemia. NUP98 gene fusions typically encode a fusion protein that retains the amino terminus of NUP98; in this context, it is important to note that several recent studies have demonstrated that the amino-terminal portion of NUP98 exhibits transcription activation potential. Approximately half of the NUP98 fusion partners encode homeodomain proteins, and at least 5 NUP98 fusions involve known histone-modifying genes. Several of the NUP98 fusions, including NUP98-homeobox (HOX)A9, NUP98-HOXD13, and NUP98-JARID1A, have been used to generate animal models of both lymphoid and myeloid malignancy; these models typically up-regulate HOXA cluster genes, including HOXA5, HOXA7, HOXA9, and HOXA10. In addition, several of the NUP98 fusion proteins have been shown to inhibit differentiation of hematopoietic precursors and to increase self-renewal of hematopoietic stem or progenitor cells, providing a potential mechanism for malignant transformation.
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PMID:NUP98 gene fusions and hematopoietic malignancies: common themes and new biologic insights. 2194 99

Acquisition of self-renewal capability by myeloid progenitors to become leukemic stem cells during myeloid leukemia development is poorly understood. Here, we show that Setbp1 overexpression efficiently confers self-renewal capability to myeloid progenitors in vitro, causing their immortalization in the presence of stem cell factor and IL-3. Self-renewal after immortalization requires continuous Setbp1 expression. We also found that Hoxa9 and Hoxa10 mRNA are present at dramatically higher levels in Setbp1-immortalized cells compared with other immortalized cells, and are induced shortly after Setbp1 expression in primary myeloid progenitors. Suppression of either gene in Setbp1-immortalized cells drastically reduces their colony-forming capability. Interestingly, Setbp1 protein associates with Hoxa9 and Hoxa10 promoters in chromatin immunoprecipitation assays in these cells, suggesting that both are direct transcriptional targets of Setbp1. Setbp1 also promotes self-renewal of myeloid progenitors in vivo as its coexpression with BCR/ABL transforms primary mouse myeloid progenitors, generating aggressive leukemias in recipient mice resembling chronic myelogenous leukemia (CML) myeloid blast crisis. Increased SETBP1 mRNA levels were also detected in a subset of CML advanced phase/blast crisis patients with high levels of HOXA9 and HOXA10 expression. Thus, Setbp1 activation represents a novel mechanism conferring self-renewal capability to myeloid progenitors in myeloid leukemia development.
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PMID:Setbp1 promotes the self-renewal of murine myeloid progenitors via activation of Hoxa9 and Hoxa10. 2256 6

Mechanisms underlying the progression of Chronic Myeloid Leukemia (CML) from chronic phase to myeloid blast crisis are poorly understood. Our previous studies have suggested that overexpression of SETBP1 can drive this progression by conferring unlimited self-renewal capability to granulocyte macrophage progenitors (GMPs). Here we show that overexpression of Hoxa9 or Hoxa10, both transcriptional targets of Setbp1, is also sufficient to induce self-renewal of primary myeloid progenitors, causing their immortalization in culture. More importantly, both are able to cooperate with BCR/ABL to consistently induce transformation of mouse GMPs and development of aggressive leukemias resembling CML myeloid blast crisis, suggesting that either gene can drive CML progression by promoting the self-renewal of GMPs. We further identify Myb as a common critical target for Hoxa9 and Hoxa10 in inducing self-renewal of myeloid progenitors as Myb knockdown significantly reduced colony-forming potential of myeloid progenitors immortalized by the expression of either gene. Interestingly, Myb is also capable of immortalizing primary myeloid progenitors in culture and cooperating with BCR/ABL to induce leukemic transformation of mouse GMPs. Significantly increased levels of MYB transcript also were detected in all human CML blast crisis samples examined over chronic phase samples, further suggesting the possibility that MYB overexpression may play a prevalent role in driving human CML myeloid blast crisis development. In summary, our results identify overexpression of HOXA9, HOXA10, and MYB as critical drivers of CML progression, and suggest MYB as a key therapeutic target for inhibiting the self-renewal of leukemia-initiating cells in CML myeloid blast crisis patients.
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PMID:Hoxa9 and Hoxa10 induce CML myeloid blast crisis development through activation of Myb expression. 2922 32