Human eosinophil Charcot-Leyden crystal protein: cloning and characterization of a lysophospholipase gene promoter

Abstract The Charcot-Leyden crystal (CLC) protein is a lysophospholipase expressed exclusively by eosinophils and basophils. During eosinophilic differentiation of eosinophil-committed cell lines, CLC steady state mRNA levels increase significantly. This increased expression is transcriptionally regulated during butyrate induction of an eosinophilic subline (C15) of the promyelocytic leukemia cell line HL- 60, as shown by nuclear run-on assays. The transcriptional start site of the CLC gene was identified 43 bp upstream of the 5′ end of the longest available cDNA sequence. The gene encoding CLC protein was cloned from a chromosome 19-specific library and a fragment overlapping the transcriptional start site was isolated and sequenced. Plasmid constructs (in the pXP2 luciferase expression vector) containing 411 and 292 bp of genomic sequence upstream of the CLC transcriptional start site directed reporter gene expression in transient transfections of HL-60-C15 cells, as well as other myeloid (U937) and nonmyeloid (HeLa and RPMI 8402) cell lines. However, the differential expression of the two CLC promoter constructs in these cell lines suggests that the -292 to -411 bp region of the promoter may confer some specificity for expression in the eosinophil lineage. The CLC promoter sequence contains two consensus GATA binding sites, a purine-rich sequence that presents potential binding sites for PU.1, a member of the ets family of genes, as well as sequences described in other myeloid-specific promoters. This is the first demonstration of a functional eosinophil promoter that could serve as a model for identifying DNA elements and trans-activating factors that regulate gene expression during the commitment and differentiation of the eosinophil lineage.

Download Full-text

Human eosinophil Charcot-Leyden crystal protein: cloning and characterization of a lysophospholipase gene promoter

Blood ◽

10.1182/blood.v82.6.1868.bloodjournal8261868 ◽

1993 ◽

Vol 82 (6) ◽

pp. 1868-1874 ◽

Cited By ~ 1

Author(s):

HI Gomolin ◽

Y Yamaguchi ◽

AV Paulpillai ◽

LA Dvorak ◽

SJ Ackerman ◽

...

Keyword(s):

Gene Expression ◽

Cell Lines ◽

Binding Sites ◽

Transcriptional Start Site ◽

Leukemia Cell ◽

Leukemia Cell Line ◽

Luciferase Expression ◽

Mrna Levels ◽

Start Site ◽

Human Eosinophil

The Charcot-Leyden crystal (CLC) protein is a lysophospholipase expressed exclusively by eosinophils and basophils. During eosinophilic differentiation of eosinophil-committed cell lines, CLC steady state mRNA levels increase significantly. This increased expression is transcriptionally regulated during butyrate induction of an eosinophilic subline (C15) of the promyelocytic leukemia cell line HL- 60, as shown by nuclear run-on assays. The transcriptional start site of the CLC gene was identified 43 bp upstream of the 5′ end of the longest available cDNA sequence. The gene encoding CLC protein was cloned from a chromosome 19-specific library and a fragment overlapping the transcriptional start site was isolated and sequenced. Plasmid constructs (in the pXP2 luciferase expression vector) containing 411 and 292 bp of genomic sequence upstream of the CLC transcriptional start site directed reporter gene expression in transient transfections of HL-60-C15 cells, as well as other myeloid (U937) and nonmyeloid (HeLa and RPMI 8402) cell lines. However, the differential expression of the two CLC promoter constructs in these cell lines suggests that the -292 to -411 bp region of the promoter may confer some specificity for expression in the eosinophil lineage. The CLC promoter sequence contains two consensus GATA binding sites, a purine-rich sequence that presents potential binding sites for PU.1, a member of the ets family of genes, as well as sequences described in other myeloid-specific promoters. This is the first demonstration of a functional eosinophil promoter that could serve as a model for identifying DNA elements and trans-activating factors that regulate gene expression during the commitment and differentiation of the eosinophil lineage.

Download Full-text

Nitric oxide modulation of human leukemia cell differentiation and gene expression

Blood ◽

10.1182/blood.v80.8.1880.1880 ◽

1992 ◽

Vol 80 (8) ◽

pp. 1880-1884 ◽

Cited By ~ 119

Author(s):

G Magrinat ◽

SN Mason ◽

PJ Shami ◽

JB Weinberg

Keyword(s):

Gene Expression ◽

Nitric Oxide ◽

Messenger Rna ◽

Interleukin 1 ◽

Leukemia Cell ◽

Leukemia Cell Line ◽

Tnf Alpha ◽

Nonspecific Esterase ◽

Human Leukemia ◽

Mrna Levels

Abstract Nitric oxide (NO) functions as an intercellular messenger molecule in such varied contexts as neurotransmission, immune regulation, and the control of vascular tone. We report that NO, delivered as purified gas or released from the pharmacologic NO donors sodium nitroprusside or 6- morpholino-sydnonimine, caused monocytic differentiation of cells of the human myeloid leukemia cell line HL-60 and altered gene expression. The treated cells stopped proliferating, became spread and vacuolated, had increased expression of nonspecific esterase and the monocyte marker CD14, and displayed increased capacity to produce hydrogen peroxide. Furthermore, these treated cells had increased steady-state expression of messenger RNA (mRNA) for tumor necrosis factor-alpha (TNF- alpha) and interleukin-1 beta (IL-1 beta), but decreased expression of mRNA for the proto-oncogenes c-myc and c-myb. The increase in TNF-alpha and IL-1 beta mRNA levels was due (at least in part) to a new transcription of these specific mRNAs. NO elaborated in the bone marrow microenvironment may have a role in normal and malignant hematopoietic cell growth and differentiation.

Download Full-text

Alternation of Cellular Morphology and Proliferation Induced by microRNA in Human Leukemia Cell Line, UT-7/EPO.

Blood ◽

10.1182/blood.v108.11.4203.4203 ◽

2006 ◽

Vol 108 (11) ◽

pp. 4203-4203

Author(s):

Nobuyoshi Kosaka ◽

Yusuke Yamamoto ◽

Nami Nogawa ◽

Keiichi Sugiura ◽

Hiroshi Miyazaki ◽

...

Keyword(s):

Cell Cycle ◽

Cell Line ◽

Cell Lines ◽

Macrocytic Anemia ◽

Leukemia Cell ◽

Leukemia Cell Line ◽

Human Leukemia ◽

Mrna Levels ◽

Rt Pcr ◽

Morphological Studies

Abstract Mature microRNA (miRNA) originated from primary miRNA (pri-miRNA) is a new group of potential regulator for cell differentiation, apoptosis, proliferation and oncogenesis. Some miRNAs were recently identified in hematopoietic cells, while the roles of miRNAs in erythrocytic and megakaryocytic cells had not been well examined. As a first step to explore for miRNAs specific for hematopoietic lineage, the expressions of several known primary microRNAs in erythrocytic and megakaryocytic cell lines, such as TF-1, HL-60, HEK293 and UT-7 leukemia cells, were examined by RT-PCR. We consequently focused on the pri-miR-10a, a primary transcript of miR-10a located within Hox gene clusters, and found the significant expression in TF-1 cells and UT-7/EPO cells. The UT-7/EPO cells were a subline established from the original UT-7 cells, as well as UT-7/GM and UT-7/TPO cells; therefore it was suitable for the further comparative analysis. Interestingly, in UT-7/EPO cells, the expression of pri-miR-10a increased under stimulation of erythropoietin (EPO; 1U/mL and 10U/mL). Based on these observations, it was postulated that pri-miR-10a might involve in modulating erythrocyte differentiation or proliferation. To clarify the role of pri-miR-10a in UT-7/EPO, we have established clonal cell lines by transfecting UT-7/EPO cells with either the control vector or the pri-miR-10a expression vector pCMV-pri-miR10a. Overexpression of pri-miR-10a in the UT-7/EPO cell line (miR10a-UT-7/EPO) was confirmed by RT-PCR. MiR10a-UT-7/EPO showed higher proliferation rate even at low concentration of EPO (0.1 mU/mL). Overexpression of pri-miR-10a did not appear to affect HOXB4 and HOXA1 expression, as similar mRNA levels were seen in both cell lines. It was notable that the cellular size of miR10a-UT-7/EPO became larger than its parental cells. Morphological studies of miR10a-UT-7/EPO were performed in detail. It is possible that miR-10a was capable to modulate morphological features particularly in cellular size relating to cell cycle regulation. For instance, loss of the E2F family members result in marked macrocytic anemia with megaloblastic features in adult mice (Mol Cell. 2000 Aug;6(2):281–91., Mol Cell Biol. 2003 May;23(10):3607–22., Blood. 2006 Aug 1;108(3):886–95.). Data presented here hypothesized that the roles of miR-10a in erythroid cells are tightly associated with cell cycle.

Download Full-text

RASSF2 Functions As a Tumor Suppressor in t(8;21) AML Via Promotion of Apoptosis

Blood ◽

10.1182/blood.v124.21.3590.3590 ◽

2014 ◽

Vol 124 (21) ◽

pp. 3590-3590

Author(s):

Samuel A Stoner ◽

Russell Dekelver ◽

Miao-Chia Lo ◽

Dong-Er Zhang

Keyword(s):

Gene Expression ◽

Tumor Suppressor ◽

Cell Lines ◽

Hematopoietic Cells ◽

Leukemia Cell ◽

Leukemia Cells ◽

Mrna Levels ◽

Human Cd34 ◽

Leukemia Cell Lines ◽

Cd34 Cells

Abstract The t(8;21) chromosomal translocation is one of the most common chromosomal translocations associated with acute myeloid leukemia (AML), found in approximately 12% of de novo AML cases. The majority of these cases are classified as FAB-subtype M2 AML. The t(8;21) results in the stable fusion of the AML1 (RUNX1) and ETO (RUNX1T1) genes. The AML1-ETO fusion protein is composed of the N-terminal portion of AML1, which includes the DNA-binding Runt-homology domain, and nearly the full-length ETO protein. The primary accepted mechanism by which AML1-ETO promotes leukemia development is through the aberrant recruitment of transcriptional repression/activation complexes to normal AML1 target genes. Therefore, the identification of individual genes or biological pathways that are specifically disrupted in the presence of AML1-ETO will provide further molecular insight into the pathogenesis of t(8;21) AML and lead to the possibility for improved treatment for these patients. We identified RASSF2 as a gene that is specifically downregulated in (2-4 fold) in total bone marrow of t(8;21) patients compared to non-t(8;21) FAB-subtype M2 AML patients by analyzing publicly available gene expression datasets. Similarly, using a mouse model of t(8;21) AML we found Rassf2 mRNA levels to be nearly 30-fold lower in t(8;21) leukemia cells compared to wild-type Lin-Sca-cKit+ (LK) myeloid progenitors. Gene expression analysis by RT-qPCR in leukemia cell lines confirmed that RASSF2 mRNA levels are significantly downregulated (8-10-fold) in both Kasumi-1 and SKNO-1 t(8;21) cell lines as compared to a similar non-t(8;21) HL-60 cell line and to primary human CD34+ control cells. In addition, expression of AML1-ETO in HL-60 or CD34+ cells results in a decrease in RASSF2 mRNA expression, which further suggests that RASSF2 is a target for regulation by AML1-ETO. Assessment of published ChIP-seq data shows that AML1-ETO binds the RASSF2 gene locus at two distinct regions in both primary t(8;21) AML patient samples and in the Kasumi-1 and SKNO-1 cell lines. These regions are similarly bound by several important hematopoietic transcription factors in primary human CD34+ cells, including AML1, ERG, FLI1, and TCF7L2, implicating these two regions as important for the regulation of RASSF2 expression during blood cell differentiation. Overexpression of RASSF2 in human leukemia cell lines using an MSCV-IRES-GFP (MIG) construct revealed that RASSF2 has a strong negative effect on leukemia cell proliferation and viability. The overall percentage of GFP-positive cells in MIG-RASSF2 transduced cells markedly decreased compared to MIG-control transduced cells over a period of 14 days. This effect was primarily due to significantly increased apoptosis in the RASSF2 expressing cell populations. Similarly, we found that expression of RASSF2 significantly inhibits the long-term self-renewal capability of hematopoietic cells transduced with AML1-ETO in a serial replating/colony formation assay. AML1-ETO transduced hematopoietic cells were normally capable of serial replating for more than 6 weeks. However, AML1-ETO transduced cells co-expressing RASSF2 consistently had reduced colony number and lost their ability to replate after 3-4 weeks. This was due to a dramatically increased rate of apoptosis in RASSF2 expressing cells. RASSF2 is reported to be a tumor suppressor that is frequently downregulated at the transcriptional level by hypermethylation in primary tumor samples, but not healthy controls. Here we have identified RASSF2 as a target for repression, and demonstrated its tumor suppressive function in t(8;21) leukemia cells. Further insights into the molecular mechanisms of RASSF2 function in AML will continue to be explored. Disclosures No relevant conflicts of interest to declare.

Download Full-text

Induction of Bim Facilitates Apoptosis in Leukemia Cells Treated with HDAC Inhibitors.

Blood ◽

10.1182/blood.v108.11.1994.1994 ◽

2006 ◽

Vol 108 (11) ◽

pp. 1994-1994

Author(s):

Matthew C. Stubbs ◽

Teresa Kim ◽

Andrei Krivtsov ◽

Peter Atadja ◽

Scott A. Armstrong ◽

...

Keyword(s):

Gene Expression ◽

Histone Deacetylase ◽

Cell Lines ◽

Expression Patterns ◽

Hdac Inhibitors ◽

Leukemia Cell ◽

Glucocorticoid Resistance ◽

Leukemia Cell Line ◽

Dependent Manner ◽

Myeloid Leukemias

Abstract Lymphoblastic leukemias containing chromosomal translocations involving the Mixed Lineage Leukemia (MLL, HRX, ALL-1) gene, as well as most acute myeloid leukemias (AMLs) have relatively poor clinical prognoses due in part to intrinsic drug resistance. Therefore, new avenues are being explored for treatment of MLL-rearranged ALL and AMLs. One possible new therapeutic class currently being investigated is the histone deacetylase (HDAC) inhibitors. We utilized the histone deacetylase inhibitor NVP-LAQ824 (Novartis, Basel, Switzerland) and analyzed its effects on MLL rearranged and other myeloid leukemias. We also made use of an MLL-AF9 expressing myeloid leukemia cell line (AKLG) derived from purified murine leukemia stem cells to perform gene expression analysis on NVP-LAQ824 treated cells in order to further understand the mechanism of action of HDAC inhibitors, and to potentially identify cooperating therapeutics. NVP-LAQ824 inhibits cell growth at similar concentrations for all cell lines and primary patient samples tested (~25–50nM) as determined by MTT assay 48 hours after treatment. NVP-LAQ824 does not appear to induce apoptosis solely through inhibition of the HSP90/FLT3-ITD complex as cell lines possessing FLT3-ITD (a HSP90-chaperoned protein) and cells without this mutation have similar drug sensitivities. In fact, in cells overexpressing FLT3-ITD that are treated with NVP-LAQ824, phospho-FLT3-ITD levels do not diminish. Microarray data indicated that NVP-LAQ824 induces the BH3-only family member bim. This finding was verified by Western blotting in all cell lines and patient samples tested. Further, shRNA-mediated knockdown of Bim induced relative resistance of cells to NVP-LAQ824. The expression profile also showed similarities to gene expression patterns of dexamethasone treated cells, namely, increased bim levels and decreased expression of c-myc, raising the possibility of synergy between the two drugs. Using MTT assays, we discovered that NVP-LAQ824 in low doses (25nM) induces sensitivity to dexamethasone in glucocorticoid resistant cell lines in a glucocorticoid receptor (GR) dependent manner. Therefore, our data indicate that NVP-LAQ824 may reverse glucocorticoid resistance and may provide insight into glucocorticoid resistance in MLL rearranged leukemias. The biochemistry behind HDAC inhibitors merits further study.

Download Full-text

To Study the Proliferative Inhibition of Anticancer Drug in Two Kinds of Ph (+) Leukemia Cell Lines.

Blood ◽

10.1182/blood.v114.22.4110.4110 ◽

2009 ◽

Vol 114 (22) ◽

pp. 4110-4110

Author(s):

Yuping Gong ◽

Xi Yang ◽

Ting Niu

Keyword(s):

Gene Expression ◽

Acute Lymphoblastic Leukemia ◽

Cell Line ◽

Cell Lines ◽

K562 Cell ◽

Lymphoblastic Leukemia ◽

Leukemia Cell ◽

Myelogenous Leukemia ◽

Leukemia Cell Line ◽

Leukemia Cell Lines

Abstract Abstract 4110 Objective To study the proliferative inhibition of imatinib, daunorubicin and bortezomib in two kinds of Ph(+) leukemia cell lines: chronic myelogenous leukemia cell line K562 expressing P210 protein and acute lymphoblastic leukemia cell line SUP-B15 expressing P190 protein. Methods (1) Cell proliferation with imatinib, daunorubicin and bortezomib for 72 hours was analyzed by the MTT assay and displayed by growth curve and IC50 value. (2) The change of bcr-abl gene mRNA levels after the 48 hours' intervention of imatinib (final concentration at 0μM, 0.35μM, 1 μM) was detected by reverse transcription polymerase chain reaction (RT-PCR). Results (1) The IC50 values of K562 and SUP-B15 cells inhibited by imatinib, daunorubicin and bortezomib for 72 hours was respectively 0.286±0.06 (μmol/L), 0.303±0.009 (μmol/L), 22.127±3.592 (nmol/L) and 1.387±0.180(μmol/L), 0.117±0.017 (μmol/L), 12.350±0.740 (nmol/L), which indicated that the K562 cell line was the more sensitive to imatinib than SUP-B15 cell line, whereas the SUP-B15 cell line had the more sensitivity to daunorubicin and bortezomib. (2) There was no change of bcr-abl gene expression after the 48 hours' intervention of imatinib in both cell lines. Conclusion (1) Imatinib, daunorubicin and bortezomib had good anti-cancer effect to Ph+ leukemia cells in vitro. What's more, the K562 cell was the more sensitive to imatinib and only imatinib will have good effect on chronic myelogenous leukemia. Whereas the SUP-B15 cell had the more sensitivity to daunorubicin and bortezomib and combining imatinib with daunorubicin or bortezomib, the effect will be better on Ph(+) acute lymphoblastic leukemia. (2) The short time intervention of imatinib had no effect on the bcr-abl gene expression and imatinib could need long time to show curative effect for the Ph+ leukemia. Disclosures: No relevant conflicts of interest to declare.

Download Full-text

Akt Activation Is Important In KRAS-Mediated Multistep Leukemogenesis

Blood ◽

10.1182/blood.v116.21.4200.4200 ◽

2010 ◽

Vol 116 (21) ◽

pp. 4200-4200

Author(s):

Ashley F. Ward ◽

Angell Shieh ◽

Emily Rose Harding-Theobald ◽

Gideon Bollag ◽

Kevin Shannon

Keyword(s):

Cell Line ◽

Cell Lines ◽

Leukemia Cell ◽

Leukemia Cell Line ◽

Mrna Levels ◽

Loss Of Function ◽

Partial Loss ◽

Ras Mutations ◽

Downstream Effector ◽

Effector Pathways

Abstract Abstract 4200 Activating mutations of Ras are found in approximately 30% of all human malignancies, and 85% of these mutations are in the K-ras isoform. These mutations dysregulate cell cycle progression, proliferation and apoptosis, and have been implicated in both initiation and maintenance of tumors. While mutant K-ras thus represents an attractive therapeutic target, attempts to develop a Ras inhibitor have been unsuccessful to date. K-Ras has three canonical downstream effector pathways: MEK/Erk, PI3K/Akt, and Ral. One or more of these pathways may represent an alternative drug target for Ras-driven malignancies, but it is not yet understood how each of these pathways contributes to leukemogenesis. Partial loss-of-function Ras mutations have been identified that render oncogenic K-Ras (K-RasG12D) unable to interact with one or more downstream effectors. Our lab has previously demonstrated that one such partial loss-of-function mutation, K-RasG12D,Y64G, does not activate the PI3K/Akt pathway. Mice transplanted with hematopoietic progenitor cells transduced with MSCV vectors encoding K-RasG12D,Y64G develop an aggressive T-lineage acute lymphoblastic leukemia (T-ALL) with a median survival of 112 days (Shieh and Shannon, Blood (ASH Annual Meeting Abstracts) 2007 110: Abstract 1617). To determine if the “missing” Ras effector pathway is deregulated during multistep tumorigenesis, we generated cell lines from K-RasG12D,Y64G leukemias (n=6). Western blot analysis revealed low Ras levels and absent PTEN protein expression in 5 of 6 K-RasG12D,Y64G leukemia cell lines. Quantitative PCR analysis revealed reduced PTEN mRNA levels in these cell lines, which was not due to somatic Pten mutations. As expected, cell lines without detectable PTEN showed high pAkt levels that persisted during serum and cytokine deprivation. One K-RasG12D,Y64G leukemia cell line was remarkable because it contained high levels of Ras and retained PTEN expression. DNA sequence analysis of this cell line unexpectedly revealed both the Y64G substitution and a de novo in frame insertion of two amino acids (arginine and aspartic acid) within the switch II domain of K-Ras, between codons 69 and 70. This insertion was also identified in the primary T-ALL. Murine fetal liver cells engineered to express K-RasG12D,Y64G, 69RN70 induced a dramatic pattern of hypersensitive progenitor growth characterized by cytokine-independent colony formation and large and aberrant CFU-GM morphology in the presence of GM-CSF that was indistinguishable from cells expressing K-RasG12D. Phospho-FACS analysis of these cells revealed markedly increased expression of pAkt when compared to cells expressing K-RasWT or K-RasG12D,Y64G, and similar to pAkt levels in cells expressing K-RasG12D. Preliminary in silico structural analysis of K-RasG12D,Y64G,69RN70 suggests that this novel insertion may restore a critical salt bridge between K-Ras and PI3Kγ. These data suggest that K-RasG12D oncogenes defective in PI3K signaling are still able to cause dysregulated growth of hematopoietic cells in vitro and in vivo via the acquisition of additional mutations that restore signaling through the PI3K pathway, and strongly support simultaneously targeting multiple downstream effector pathways as a general therapeutic strategy for the substantial fraction of human cancers that contain RAS mutations. Disclosures: Bollag: Plexxicon, Inc: Employment, Equity Ownership, Patents & Royalties.

Download Full-text

Deep sequencing reveals two Jurkat subpopulations with distinct miRNA profiles during camptothecin-induced apoptosis

10.1101/237099 ◽

2017 ◽

Author(s):

İpek Erdoğan ◽

Mehmet İlyas Coşacak ◽

Ayten Nalbant Aldanmaz ◽

Bünyamin Akgül

Keyword(s):

Gene Expression ◽

T Cells ◽

Cell Lines ◽

Deep Sequencing ◽

Mirna Expression ◽

Expression Profiles ◽

Leukemia Cell ◽

Jurkat Cells ◽

Cellular Heterogeneity ◽

Leukemia Cell Line

AbstractmicroRNAs (miRNAs) are small non-coding RNAs of about 19-25 nt that regulate gene expression post-transcriptionally under various cellular conditions, including apoptosis. The miRNAs involved in modulation of apoptotic events in T cells are partially known. However, heterogeneity associated with cell lines makes it difficult to interpret gene expression signatures especially in cancer-related cell lines. Treatment of Jurkat T cell leukemia cell line with the universal apoptotic drug, camptothecin, resulted in identification of two Jurkat sub-populations: one that is sensitive to camptothecin and the other being rather intrinsically resistant. We sorted apoptotic Jurkat cells from the non-apoptotic ones prior to profiling miRNAs through deep sequencing. Our data showed that a total of 184 miRNAs were dysregulated. Interestingly, apoptotic and non-apoptotic sub-populations exhibited a distinct miRNA expression profile. In particular, 6 miRNAs were inversely expressed in these two sub-populations. The pyrosequencing results were validated by real time qPCR. Altogether these results suggest that miRNAs modulate apoptotic events in T cells and that cellular heterogeneity requires careful interpretation of miRNA expression profiles obtained from drug-treated cell lines.

Download Full-text

Nitric oxide modulation of human leukemia cell differentiation and gene expression

Blood ◽

10.1182/blood.v80.8.1880.bloodjournal8081880 ◽

1992 ◽

Vol 80 (8) ◽

pp. 1880-1884 ◽

Cited By ~ 2

Author(s):

G Magrinat ◽

SN Mason ◽

PJ Shami ◽

JB Weinberg

Keyword(s):

Gene Expression ◽

Nitric Oxide ◽

Messenger Rna ◽

Interleukin 1 ◽

Leukemia Cell ◽

Leukemia Cell Line ◽

Tnf Alpha ◽

Nonspecific Esterase ◽

Human Leukemia ◽

Mrna Levels

Nitric oxide (NO) functions as an intercellular messenger molecule in such varied contexts as neurotransmission, immune regulation, and the control of vascular tone. We report that NO, delivered as purified gas or released from the pharmacologic NO donors sodium nitroprusside or 6- morpholino-sydnonimine, caused monocytic differentiation of cells of the human myeloid leukemia cell line HL-60 and altered gene expression. The treated cells stopped proliferating, became spread and vacuolated, had increased expression of nonspecific esterase and the monocyte marker CD14, and displayed increased capacity to produce hydrogen peroxide. Furthermore, these treated cells had increased steady-state expression of messenger RNA (mRNA) for tumor necrosis factor-alpha (TNF- alpha) and interleukin-1 beta (IL-1 beta), but decreased expression of mRNA for the proto-oncogenes c-myc and c-myb. The increase in TNF-alpha and IL-1 beta mRNA levels was due (at least in part) to a new transcription of these specific mRNAs. NO elaborated in the bone marrow microenvironment may have a role in normal and malignant hematopoietic cell growth and differentiation.

Download Full-text