scholarly journals Overexpression of HOXA10 in murine hematopoietic cells perturbs both myeloid and lymphoid differentiation and leads to acute myeloid leukemia.

1997 ◽  
Vol 17 (1) ◽  
pp. 495-505 ◽  
Author(s):  
U Thorsteinsdottir ◽  
G Sauvageau ◽  
M R Hough ◽  
W Dragowska ◽  
P M Lansdorp ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Hox Genes ◽  
Bone Marrow Cells ◽  
Expression Patterns ◽  
Hematopoietic Cells ◽  
B Lymphoid ◽  
Acute Myeloid ◽  
Marrow Cells

Multiple members of the A, B, and C clusters of Hox genes are expressed in hematopoietic cells. Several of these Hox genes have been found to display distinctive expression patterns, with genes located at the 3' side of the clusters being expressed at their highest levels in the most primitive subpopulation of human CD34+ bone marrow cells and genes located at the 5' end having a broader range of expression, with downregulation at later stages of hematopoietic differentiation. To explore if these patterns reflect different functional activities, we have retrovirally engineered the overexpression of a 5'-located gene, HOXA10, in murine bone marrow cells and demonstrate effects strikingly different from those induced by overexpression of a 3'-located gene, HOXB4. In contrast to HOXB4, which causes selective expansion of primitive hematopoietic cells without altering their differentiation, overexpression of HOXA10 profoundly perturbed myeloid and B-lymphoid differentiation. The bone marrow of mice reconstituted with HOXA10-transduced bone marrow cells contained in high frequency a unique progenitor cell with megakaryocytic colony-forming ability and was virtually devoid of unilineage macrophage and pre-B-lymphoid progenitor cells derived from the transduced cells. Moreover, and again in contrast to HOXB4, a significant proportion of HOXA10 mice developed a transplantable acute myeloid leukemia with a latency of 19 to 50 weeks. These results thus add to recognition of Hox genes as important regulators of hematopoiesis and provide important new evidence of Hox gene-specific functions that may correlate with their normal expression pattern.

The Growth Inhibition and Apoptosis Induction of Acute Myeloid Leukemia Blast Population by the Blocking IGF-IR Pathway.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4515-4515
Author(s):  
Si Sun ◽  
Yanli He ◽  
Xingbing Wang ◽  
Wei Liu ◽  
Jun Liu ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Bone Marrow Cells ◽  
Pi3k Pathway ◽  
Leukemia Cell Line ◽  
Free System ◽  
Acute Myeloid ◽  
Marrow Cells

Abstract The insulin-like growth factor-1receptor (IGF-1R) is overexpressed in a variety of tumors and has been associated with cancer development. Here, we analysis the IGF-IR expression on the bone marrow cells from 45 newly diagnosed patients with acute myeloid leukemia (AML) by flow cytometry. IGF-1R universally expressed on AML blasts and the leukemia cell line HL-60, did not show significant correlation with FAB subtypes. However, the bone marrow cells from AML patients with high myeloblast counts (>80%) generally showed brighter IGF-IR expressions, which indicated the IGF-IR pathway might play an important role for AML blast proliferation and survival. Indeed, blocking the IGF-1R pathway by neutralizing monoclonal antibodies could reduce the proliferation of HL-60 cells by 38.28% at 48 hr. This inhibitory effect on blast growth was observed in 4 of 5 AML samples. In the same IGF-1R blocking treatment, the apoptosis of HL-60 cells was significantly induced, resulting in apoptosis of 57% of the cell population with the measurement of Annexin V vs PI staining by flow cytometry. The control contained only 20% apoptotic cells. We also demonstrated that the blockade of the IGF-1R pathway inhibited the phophorylation of the PI3K pathway component Akt in HL-60 cells when cultured in a serum free system with a supplement of 50ng/ml exogenous IGF. Since PI3K pathway activation greatly contributes to the proliferation, survival and drug resistance of AML, it is of interest to study whether blockading IGF-IR could also inhibit the PI3K pathway in primary AML blasts and synergize other anti-leukemia agents to improve the therapeutic effectiveness. Conclusions: IGF-IR may play an important role in the proliferation and survival of the AML blast population; Blocking the IGF-IR pathway could significantly inhibit the growth of AML blasts and considerably induce the apoptosis of AML blasts; IGF-IR could become a critical molecular target in anti-leukemia drug discovery.

Acute Myeloid Leukemia Cells Generate Leukemic Endothelial Cells with Leukemogenic Potential: Blood Vessels As Sanctuaries for Leukemia Relapse

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 241-241
Author(s):  
Christopher R Cogle ◽  
Gerard J Madlambayan ◽  
Devorah C Goldman ◽  
Azzah Al Masri ◽  
Ronald P. Leon ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Endothelial Cell ◽  
Blood Vessels ◽  
Myeloid Leukemia ◽  
Bone Marrow Cells ◽  
Surface Proteins ◽  
Nsg Mice ◽  
Acute Myeloid ◽  
Marrow Cells

Abstract Abstract 241 Human hematopoietic stem cells (HSCs) possess hemangioblast activity, which is defined as the ability to generate both blood and endothelium. Whether malignant HSC counterparts such as acute myeloid leukemia (AML) also display this bipotentiality remains to be defined. To test the hemangioblast potential of AML cells we first cultured primary human AML bone marrow in conditions established by Yoder and colleagues that support the growth of functional endothelial cell (EC) progenitors. AML cultured in endothelial colony forming cell (ECFC) media generated endothelial progenitor cell colonies that showed uptake of acetylated LDL and expressed several EC surface proteins, including CD105, CD146, UEA-1 and CD144. Importantly, ECFCs derived from AML bone marrow no longer expressed CD45 or myeloid surface proteins such as CD14. When placed in Matrigel, these AML derived ECFC generated capillary-like, tubular structures. Moreover, these ECFCs contained cytogenetic mutations associated with their parental leukemias. Thus, under the appropriate conditions, AML bone marrow cells can generate cells with an endothelial-like phenotype and harboring leukemia specific mutations that will be referred to as ‘L-ECFC.' To functionally define leukemia hemangioblast activity, a xenograft model of AML was employed. Sublethally irradiated NOD/scid/IL2Rγ−/− (NSG) mice were transplanted with primary human AML cells and then sacrificed at 8–36 weeks after transplant. Significant accumulations of human AML cells were found in perivascular regions of the liver. Both tight coupling and bona fide cell fusion between AML and ECs was observed. AML derived EC that were integrated into portal vein endothelium showed induction of CD105 expression Follow-up AML xenotransplant experiments with BrdU labeling revealed almost four-fold fewer (6%) of the AML cells incorporated within blood vessels were BrdU+, as compared to AML cells not integrated in blood vessels (22%) (P=0.01). These results suggest that AML cell incorporation within the endovascular lining induces cell quiescence. Thus, leukemia-integrated ECs may be less susceptible to cell cycle active agents like cytarabine. Results from these experiments also raised the possibility that AML cells adopting an endothelial-like phenotype may serve as a reservoir for leukemic relapse. To test this hypothesis, we injected CD105+CD45- L-ECFC derived from AML patients into NSG mice. These L-ECFC generated colonies of human CD105+CD45- within spleens and bone marrow of recipient mice. We also found a distinct population of human CD45+CD19- cells comprising 5–10% of bone marrow cells. Leukemia-derived cells were confirmed by detection of cytogenetically mutant cells consistent with the parent leukemia (e.g., MLL duplications). In conclusion, this study demonstrates that AML cells can functionally generate leukemic ECs that become quiescent after incorporation in blood vessel networks and can re-emerge with a leukemogenic phenotype. Together, our results raise the strong possibility that AML cells exhibit functional hemangioblast activity and that vascular endothelium may serve as a clinically important sanctuary for occult leukemia. Our data also support endothelial cell targeting strategies as a means to eradicate AML. Disclosures: No relevant conflicts of interest to declare.

t(6;9) in bone marrow cells in two patients with sarcoidosis and acute myeloid leukemia

1989 ◽  
Vol 38 (2) ◽  
pp. 297-300 ◽  
Author(s):  
I. Nordenson ◽  
L. Bjermer ◽  
G. Holmgren ◽  
P. Hörnsten ◽  
A. Wahlin
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Bone Marrow Cells ◽  
Acute Myeloid ◽  
Marrow Cells

scholarly journals SETDB1 Represses Hox Gene Expression and Suppresses Acute Myeloid Leukemia

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1320-1320
Author(s):  
James Ropa ◽  
Nirmalya SAHA ◽  
Andrew G. Muntean
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Colony Formation ◽  
Myeloid Leukemia ◽  
Target Genes ◽  
Bone Marrow Cells ◽  
Ex Vivo ◽  
Hematopoietic Cells ◽  
H3k9 Methylation ◽  
Acute Myeloid

Abstract Epigenetic regulators play an important role in normal and malignant hematopoiesis. Epigenetic deregulation of the HOXA gene cluster drives transformation of about 50% of acute myeloid leukemia (AML), including those harboring MLL rearrangements and NPM mutations, as well as others. Expression of Hoxa9 and its co-factor Meis1 is sufficient to transform bone marrow into a lethal AML in mouse models. We previously demonstrated that the pro-leukemic genes Hoxa9 and Meis1 are critically regulated by the histone H3 Lysine 9 (H3K9) methyltransferase SETDB1. Recent studies show that SETDB1 is required for normal hematopoiesis and MLL-AF9 mediated leukemia (Koide, et al. Blood 2016). Our lab recently demonstrated that SETDB1 negatively regulates the expression of HoxA9 and Meis1 through deposition of promoter H3K9 methylation in MLL-AF9 AML cells (Ropa et al. Oncotarget 2018). Consistent with these data, HOXA9 and MEIS1 expression negatively correlates with SETDB1 expression in AML patient samples. Therefore, we investigated the biological impact of SETDB1 on AML. We first noted that expression of SETDB1 in AML patient samples is significantly lower compared to normal hematopoietic cells. Further, higher SETDB1 expression correlated with a significantly better overall survival (p=0.003) and lower expected hazard (HR=0.9/100RSEM; p=0.009) in AML patients compared with lower SETDB1 expression. These data are consistent with SETDB1 negatively regulating pro-leukemic genes and suggests that SETDB1 expression may be correlated with AML patient prognosis. We tested this directly by expressing high levels of SETDB1 in AML cells. Ex vivo assays show that retroviral overexpression of SETDB1 in MLL-AF9 AML cells leads to cell differentiation, decreased leukemia colony formation, and decreased cell proliferation. Consistent with the AML patient data, overexpression of SETDB1 significantly delays MLL-AF9 mediated leukemogenesis in vivo (p=0.01). Further, we observed a strong selective pressure against exogenous SETDB1 expression in moribund mice. Transcriptome analyses demonstrate that SETDB1 globally represses Hox and pluripotency gene programs. Strikingly, we found that SETDB1 represses many of the same genes that exhibit reduced promoter H3K9me3 in AML patient samples relative to CD34+ cells. These data point to a role for SETDB1 in negatively regulating pro-leukemic target genes and suppressing AML. We also explored how chemical and genetic inhibition of H3K9 methylation and Setdb1 affects AML initiation and maintenance. We first confirmed the previously reported requirement for Setdb1 in AML cell lines by genetically deleting both alleles of Setdb1 in MLL-AF9 cells, which resulted in a complete arrest of proliferation (Koide, et al. Blood 2016). Combined with our data presented above, these results suggest a narrow window of SETDB1 expression is maintained in AML cells. To achieve reduced (but not complete loss of) activity, we investigated how small molecule inhibition of H3K9 methylation (UNC0638) or shRNA mediated knock down of Setdb1 affects AML initiation. We observed increased ex vivo colony formation of normal ckit+ bone marrow cells upon shRNA mediated knockdown of Setdb1 or upon UNC0638 treatment. We hypothesized that this expansion of colony forming unit potential of hematopoietic cells may translate to increased transformation potential by leukemic oncogenes. Indeed, cells pretreated with UNC0638 followed by retroviral transduction with MLL-AF9 exhibit significantly higher capacity for leukemic colony formation than vehicle treated cells. These data are consistent with H3K9 methylation repressing genes required for AML transformation. Our data identified a narrow window of expression of SETDB1 in AML patient samples. SETDB1 expression is reduced in AML patients relative to normal cells and chemical inhibition of H3K9 methylation expands the pool of cells amenable to MLL-AF9 mediated transformation ex vivo. While inhibition of SETDB1 and other H3K9 methyltransferases has been suggested as a possible therapeutic strategy, our data suggests this may also prime bone marrow cells for transformation by inhibiting epigenetic processes that repress pro-leukemic target genes. Further investigation of the roles of SETDB1 and H3K9 methylation levels is necessary to determine the value of these epigenetic modifiers as therapeutic targets in AML and is currently ongoing. Disclosures No relevant conflicts of interest to declare.

Continued Expression of the NRAS(G12V) Oncogene Is Required for the Maintenance of Acute Myeloid Leukemia Induced in Cooperation with MLL-AF9.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1615-1615
Author(s):  
Won-Il Kim ◽  
Ilze Matise ◽  
Miechaleen Diers ◽  
David Largaespada
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Transgenic Mice ◽  
Myeloid Leukemia ◽  
Bone Marrow Cells ◽  
Scid Mice ◽  
Myeloid Lineage ◽  
Blast Cells ◽  
Acute Myeloid ◽  
Marrow Cells

Abstract To study the role of the NRAS(G12V) oncogene in the context of acute myeloid leukemia (AML) cells developing with in cooperation with MLL fusion oncogene (MLL-AF9), we used a Vav promoter-Tet transactivator (Vav-tTA)-driven repressible system of NRAS(G12V) expression in Mll-AF9 mice. Vav-tTA; TRE-NRAS(G12V); Mll-AF9 triply-transgenic mice were generated by crossing the Vav-tTA; TRE-NRAS(G12V) doubly-transgenic FVB/n and Mll-AF9 knock-in BL6 mice. The triply-transgenic FVB/n × BL6 F1 mice expressing both the NRAS(G12V) and Mll-AF9 transgenes developed AML, which showed a trend of decreased latency compared with those carrying only the Mll-AF9 knock-in transgene. Mast cell disease also occurred accordingly in the Vav-tTA; TRE-NRAS(G12V) co-transgenic mice. Since the mastocytosis disease is not transplantable, we transplanted bone marrow cells from four independent AML mice into recipient SCID mice to determine whether NRAS(G12V) expression is necessary to maintain AML in the recipient mice without mastocytosis. Continuously treating the transplanted SCID mice with doxycycline (Dox) in drinking water, we found the expression of NRAS(G12V) oncogene was required for AML persistence in three out of the four independent primary AML cells. Furthermore, we transplanted the AML bone marrow cells previously xenografted in the recipient SCID mice into other SCID mice to conditionally repress NRAS(G12V) expression only after the transplanted AML was fully established. We found the number of WBC cells was greatly decreased 4–6 days after the Dox treatment and this was correlated with the significant increase of apoptotic cells in bone marrow and peripheral bloods. The transplanted AML blast cells underwent apoptosis and were mostly removed from the circulating blood, bone marrow, and spleen after 8 days post Dox treatment. In 2–3 weeks after beginning Dox treatment and observing AML remission, Dox-resistant leukemia relapse was observed in recipient SCID mice. The relapsed leukemia failed to express NRAS(G12V) and showed significantly reduced aggressiveness along with less myelosuppression and more differentiated myeloid lineage cells than AML prior to repression of NRAS(G12V) expression. The NRAS(G12V)-independent relapsed disease histopathologically resembles an aggressive myeloproliferative disease (MPD) rather than AML, because the proportion of AML blast cells was less than 20% of myeloid lineage cells. The NRAS(G12V)-independent MPD could be transplanted into recipient SCID mice, but the subsequent anemia was greatly attenuated compared to transplant of the same AML clone expressing NRAS(G12V). We conclude that NRAS(G12V) can be a good molecular target to treat AML, because NRAS(G12V) expression is required for persistence and specific malignant features in AML induced in cooperation with MLL-AF9. Targeting NRAS(G12V) can strongly disturb the maintenance of AML blast cells and myelosuppression, although leukemia cells can relapse without NRAS(G12V) expression.

Direct versus cultured preparation of bone marrow cells from 22 patients with acute myeloid leukemia

1982 ◽  
Vol 60 (3) ◽  
pp. 281-283 ◽  
Author(s):  
Peter H. Fitzgerald ◽  
Christine M. Morris ◽  
Lynette M. Giles
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Bone Marrow Cells ◽  
Acute Myeloid ◽  
Marrow Cells
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