Aminopeptidase Inhibitor Bestatin Potentiates the Induced-Differentiation Activity of All-trans-Retinoic Acid in NB4 Cells Possibly through Down-Regulating c-myc Expression.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4443-4443
Author(s):  
Mao-fang Lin ◽  
Xi-jun Qian

Abstract All-trans-retinoic acid (ATRA) represents the sole example of clinically useful cyto-differentiating agent. ATRA treatment alone results in complete remission of nearly 80% patients with acute promyelocytic leukemia (APL). However, the therapeutic use of this compound is limited by a number of problems, including the systemic toxicity and ATRA resistant leukemia. One way to circumvent these problems is to identify the agents capable of enhancing the pharmacologic activity of ATRA. As we know, an aminopeptidase inhibitor, bestatin, had been used as an immunomodulator in anti-tumor therapy. Recently, we have reported bestatin can induce apoptosis in HL-60 and K562 cells. In the present study, we investigated whether bestatin can potentiate the ATRA induced-differentiation of APL cell line NB4 cells and whether changes of transcription factors expression are involved in this course. The cellular morphology observed by optical microscopy, the expression level of CD11b measured by flow cytometry and the nitroblue-tetrazolium (NBT) reduction assay was performed to determine the cyto-differentiation in NB4 cells. The mRNA expression levels of c-myc and c-EBPε in NB4 cells were detected by RT-PCR. NB4 cells incubated with 10nM ATRA plus 100μg/ml bestatin showed more morphologic character of metamyelocyte and band neutrophil than that of the cells treated by ATRA alone. Compared with 10nM ATRA used alone, after treating NB4 cells for 72 hours, the addition of various concentration of bestatin (50μg/ml, 75μg/ml, 100μg/ml) dose-dependently enhancesd NBT reduction of NB4 cells (17.6±2.5 vs. 12.0±2.2, p<0.05; 23.5±3.2 vs. 12.0±2.2, p<0.01; 36.0±8.3 vs. 12.0±2.2, p<0.01, respectively). 100μg/ml bestatin time-dependently increased 10nM ATRA induced NBT reduction of NB4 cells from 24 to 72 hours (p<0.01). The effect of various concentration of ATRA in combination with 100μg/ml bestatin was statistically different with the sum of the effects of individual drugs after subtracting the value of background (31.2±9.1 vs. 12.7±4.3, p<0.01; 39.5±5.0 vs.16.0±1.8, p<0.001; 49.6±5.3 vs. 22.1±1.6, p<0.001, respectively). Moreover, 10nM ATRA plus 100μg/ml bestatin could prominently elevate CD11b expression in NB4 cells compared with ATRA alone treated NB4 cells group(60.58±9.18% vs. 31.95±5.52%, p<0.01), while 100μg/ml bestatin could not induced significant changes in the expression level of CD11b in NB4 cells after 72 hours incubation. The various concentration (50μg/ml, 75μg/ml, 100μg/ml) of bestatin synergizes with 10nM ATRA to down-regulate the expression level of c-myc mRNA (p<0.01), which was inversely correlated with the NBT reduction activity of NB4 cells induced by 10nM ATRA plus various concentration bestatin (r=−0.917, p=0.028). However, 100μg/ml bestatin plus 10nM ATRA could not induce any significant changes in the expression level of c-EBPε mRNA compared with ATRA treated alone group. In conclusion, an aminopeptidase inhibitor bestatin can potentiate ATRA-induced differentiation of NB4 cells, which may be through down-regulating the expression of c-myc in concert with ATRA. Bestatin would be useful in anti-APL therapy by enhancing the pharmacologic activity of ATRA.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4456-4456 ◽  
Author(s):  
Ameet R. Kini ◽  
Moolky Nagabhushan ◽  
Martin S. Tallman ◽  
Shantanu Roychowdhury

Abstract The introduction of ATRA-based differentiation therapy has significantly enhanced outcomes in patients with APL. However, retinoic acid syndrome and ATRA-resistance remain significant concerns. It would therefore be useful to develop drugs that reduce the therapeutic doses of ATRA needed, and would be effective in ATRA-resistant cases. We have shown previously that curcumin, the yellow compound isolated from spice turmeric, suppresses the initiation and promotion stages of cancer development. In the present study we evaluated whether curcumin affects differentiation of NB4 APL cells. The NB4 cells were derived from a patient with APL, and differentiate in response to ATRA, while NB4-R1 cells are resistant to ATRA. Treatment of NB4 cells with 5 μM curcumin enhanced ATRA-mediated differentiation. Differentiation was assessed by evaluating CD11b expression, nitroblue tetrazolium (NBT) reduction and by morphologic examination. This curumin-mediated enhanced differentiation was apparent at 1 μM as well as 0.1 μM of ATRA. Curcumin alone did not cause differentiation of the NB4 cells, although higher concentrations of curcumin caused apoptosis. We then examined the effect of curcumin on the ATRA-resistant NB-R1 cells. Addition of ATRA and curcumin together induced differentiation of the NB4-R1 cells, whereas either agent alone did not cause differentiation. The differentiation was characterized by increased CD11b expression, NBT reduction and the typical morphologic changes. In addition, differentiation of the NB4-R1 cells was accompanied by restoration of the PML-oncogenic domains (PODs). These results indicate that curcumin may be another unconventional therapeutic agent in APL, following the successful use of ATRA and arsenic trioxide.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3827-3827
Author(s):  
Kenichi Sakamoto ◽  
Toshihiko Imamura ◽  
Mio Yano ◽  
Hideki Yoshida ◽  
Atsushi Fujiki ◽  
...  

Abstract Background Among the subtypes of acute myeloid leukemia (AML), acute promyelocytic leukemia (APL) responds dramatically to differentiation therapy with all-trans retinoic acid (ATRA). But, ATRA is not sufficient to induce differentiation in non-APL AML. Herein, we first evaluated whether MLL fusion partners, such as MLL-AF9 and MLL-AF4/AF5q31, affect the sensitivity of ATRA in human and murine MLL fusion positive AML cell lines. In addition, we also assessed the level of H3K4me2 modification for the RARα gene in human AML cell lines, and whether the LSD1 inhibitor affected the ATRA-resistant MLLfusion positive AML cell lines. Methods Three human AML cell lines with MLL fusion (THP1 and MOLM13 expressing MLL-AF9, and KOCL48 expressing MLL-AF4) and two murine leukemic cell lines derived from murine Lin- hematopoietic progenitors transduced by retroviral vector expressing MLL fusion genes, such as MLL-AF9 and MLL-AF5q31 were used in this study. To test the sensitivity of ATRA, all cell lines were treated with 1 μM ATRA for three days. Monocytic differentiation was assessed by morphological analysis, NBT reduction test and flow cytometric analysis (FCM) of CD11b expression. Quantitative RT-PCR (qRT-PCR) analysis and western blotting was carried out to measure the RARα, C/EBPα, C/EBPε, and PU.1 expressions. Cytotoxicity assay was performed to determine the IC50 of ATRA in these cell lines and whether ATRA could decrease the IC50 of cytarabine in MLL-AF9positive cells by using WST assays. Chromatin immunoprecipitation (ChIP) assay was performed to determine the value of H3K4me2 status using RARα-specific primers. To determine whether tranylcypromine (TCP), which is a nonreversible LSD1 inhibitor, could reactivate ATRA sensitivity, we treated KOCL48 with 10 μM TCP and 1μM ATRA. Results We first determined that morphological changes characteristic of monocytic differentiation, CD11b expression and NBT reduction are more readily induced by ATRA in human and murine MLL-AF9 positive cells than MLL-AF4/AF5q31 positive cells. The NBT reduction percentage was 12.5±3.77 in THP1, 13.1±2.02 in MOLM13, but 7.00±2.64 in KOCL48 cells (p<0.05). The ATRA treatment also induced growth inhibition and increased gene expression related to monocytic differentiation through retinoic acid (RA) pathway, more efficiency in MLL-AF9 positive cells than MLL-AF4/AF5q31 cells. The IC50 of ATRA for THP1, MOLM13 and murine MLL-AF9 cells was 3.85, 1.24 and 1.95 μM, but over 10 μM for KOCL48 and murine MLL-AF5q31 cells. Furthermore, qRT-PCR and western blot revealed that ATRA increased expression level of RARα, C/EBPα, C/EBPε, and PU.1 in MLL-AF9 positive cells, but not in MLL-AF4/AF5q31 positive cells. Collectively, RA pathway is more impaired in MLL-AF4/AF5q31 positive cells than MLL-AF9 positive cells. In addition, the increase in RARα, C/EBPα, C/EBPε, and PU.1 mRNA expressions were observed in two primary MLL-AF9 positive AML cells treated with ATRA. Next, we also carried out ChIP assay and the H3K4me2/ H3 on the RARα promoter in MLL-AF9 positive cells were higher than MLL-AF4 positive cell. Furthermore, ATRA and TCP combination treatment in KOCL48 induced morphological changes, CD11b expression, and increased the expression level of RARα, C/EBPα, C/EBPε, and PU.1, suggesting that inhibition of LSD1 restores ATRA sensitivity. Finally, ATRA in combination with cytarabine treatment in MLL-AF9 positive cells enhanced cytarabine sensitivity: the IC50 of cytarabine in THP1, MOLM13, and murine MLL-AF9cells was 4.18, 0.04, and0.065 μM without ATRA and 0.13, 0.0005, and 0.015 μM with ATRA, respectively. Conclusions Our data demonstrated that RA pathway was more profoundly impaired in MLL-AF4/AF5q31 positive cells than MLL-AF9 positive cells, suggesting type of MLL fusion protein contributes inactivation of RA pathway. Our data also identified the sensitivity of ATRA was correlated with the ratio of H3K4me2/ H3 on the RARα promoter, and TCP restore the sensitivity of ATRA in KOCL48, suggesting the decrease of the H3K4me2/H3 plays a role in inactivation of RA pathway. Additionally, we revealed that synergistic antileukemic activity of ATRA in combination with cytarabine in MLL-AF9 positive cells. Therefore, ATRA in combination with cytarabine might be novel therapeutic option for the ATRA sensitive AML cells, especially for MLL-AF9 positive cells. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5040-5040
Author(s):  
Pengcheng He ◽  
Mei Zhang ◽  
Xiaoning Wang ◽  
Jun Qi ◽  
Jieying Xi ◽  
...  

Abstract More than 90% patients with untreated acute promyelocytic leukemia(APL) obtain complete remission clinically by using All-trans retinoic acid(ATRA), a strong differentiation inducer. However, the rapid development of ATRA-resistance brings a new problem to the treatment of APL. Interferon(IFN), as an important cytokine, has broad biological activities. It can not only inhibit the growth of tumor cells, but also reverse the drug-resistance of chemotherapy. As proved by some research, the mechanisms of ATRA-resistance are probably related to lacking some important proteins which synthesized by Interferon-γ (IFN-γ). In order to explore a new way to solve the problem of ATRA-resistance in APL, we investigate the effect and mechanisms of IFN-γ in combination with ATRA on the proliferation/differentiation of NB4 cells(APL cell line with ATRA-sensitiveness) and MR2 cells(APL cell line with ATRA-resistance) respectively. ATRA, IFN-γ and IFN-γ in combination with ATRA were incubated with NB4 and MR2 cells respectively. The cell proliferation was tested by MTT assay, the cell differentiation was tested through light microscope, by NBT reduction test and flow cytometry(FCM). The results showed that ATRA could inhibit the growth of NB4 cells significantly (P&lt;0.05), but it had no effect on the growth of MR2 cells (P&gt;0.05). IFN-γ could inhibit the growth of both NB4 cells and MR2 cells slightly (P&lt;0.05). Moreover, the growth inhibition effect of IFN-γ in combination with ATRA on NB4 and MR2 cells was obviously stronger than that of any single drug group (P&lt;0.05). The results of cell morphology observation, NBT reduction test and CD11b antigen detection showed that ATRA could induce differentiation of NB4 cells significantly (P&lt;0.05), but it had no effect on MR2 cells (P&gt;0.05). Although IFN-γ alone had no effect on the differentiation of either NB4 or MR2 cells (P&gt;0.05), it could augment the differentiation of NB4 cells induced by ATRA (P&lt;0.05) and induce the differentiation of MR2 cells slightly (P&lt;0.05) when it combined with ATRA. Furthermore, we have observed the expression of promyelocytic leukemia(PML) protein by indirect immune fluorescent test. The results showed that the number of fluorescent particles in both NB4 and MR2 cells’ nucleus was increased significantly (P&lt;0.05) when they were incubated with IFN-γ respectively, which indicated IFN-γ could induce the expression of PML protein, a tumor growth inhibitor. It can be seen that IFN-γ could augment the proliferation inhibition effect of ATRA on NB4 and MR2 cells through enhancing the expression of PML protein. Moreover, IFN-γ in combination with ATRA not only can strengthen the induction differentiation effect of ATRA on NB4 cells, but also can partially induce the maturation of MR2 cells with ATRA-resistance.


Blood ◽  
1993 ◽  
Vol 81 (2) ◽  
pp. 475-481 ◽  
Author(s):  
C Labbaye ◽  
J Zhang ◽  
JL Casanova ◽  
M Lanotte ◽  
J Teng ◽  
...  

Abstract Retinoic acid is known to induce differentiation of human myeloid leukemia cells in vitro. Recently, all-trans retinoic acid has been used to induce remissions in patients with acute promyelocytic leukemia, probably through differentiation of the leukemia cells. Myeloblastin (mbn) is a protease that has been identified in the human leukemia cell line HL-60. Downregulation of this protease can inhibit proliferation and induce differentiation of HL-60-derived leukemia cells. Here we have investigated the regulation of mbn messenger RNA (mRNA) expression in two human leukemia cell lines, HL-60 and NB4, treated with all-trans retinoic acid. Under this treatment, downregulation of mbn mRNA was observed in both cell lines, but was considerably delayed in NB4 cells that carry the t(15;17) translocation characteristic of acute promyelocytic leukemia. We have found that multiple mechanisms were involved in the control of mbn mRNA expression. These mechanisms were different in HL-60 and NB4 cells. Our results show that in HL-60 cells, all-trans retinoic acid rapidly decreased transcription of mbn. In contrast, in the t(15;17)-positive NB4 cells treated with all-trans retinoic acid, upregulation of mbn mRNA expression was followed by a late downregulation, both achieved via posttranscriptional mechanisms.


PLoS ONE ◽  
2013 ◽  
Vol 8 (10) ◽  
pp. e75258 ◽  
Author(s):  
Nadja Blagitko-Dorfs ◽  
Yi Jiang ◽  
Jesús Duque-Afonso ◽  
Jan Hiller ◽  
Arzu Yalcin ◽  
...  

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4385-4385
Author(s):  
Aschwin L. Menke ◽  
Ruth H.J.N. Knops ◽  
Jurgen A.F. Marteijn ◽  
Willemijn Wissink ◽  
Josie Smeets ◽  
...  

Abstract Acute myeloid leukemia is characterized by the uncontrolled proliferation of immature cells that have lost their ability to differentiate. In the case of acute promyelocytic leukemia (AML-M3), the cells can be forced to differentiate by pharmacological dosages of all-trans retinoic acid (ATRA), a phenomenon that is successfully used in the treatment of APL patients. About 70% of the patients, suffering from PML-RARa -positive acute promyelocytic leukemia, can be cured with a combination of ATRA and anthracycline - based chemotherapy. However, relapse remains a major problem. The molecular mechanisms by which the retinoic acid receptors mediate their biological functions have been studied extensively and although various retinoic acid-responsive genes have been identified, the target genes that are crucially involved in leukemogenesis are unknown. The Wilms’ Tumor 1 gene, has been implicated in the development of leukemia. WT1 overexpression can be detected in most acute leukemias and is particularly highly expressed in APL cells. Several groups have found an inverse correlation between the expression levels of WT1 and the overall survival of leukemia patients. The underlying mechanism, however, remains to be elucidated. We have shown that the Wilms’ Tumor 1 (WT1) is strongly downregulated in APL cells, during ATRA-induced differentiation. Using a newly developed realtime RT-PCR method we have found that the expression levels of all four major WT1 isoforms are downregulated. To study the biological activity of each WT1-isoform, we have retrovirally transduced the APL cell line NB4, with the 4 major WT1 isoforms and analyzed the effect on ATRA-induced differentiation. Using flowcytometry and NBT staining, we show that ectopic expression of the different WT1-isoform inhibited ATRA-induced differentiation and subsequently, the apoptosis of APL cells, albeit with different potential. WT1-transduced cells survived pharmacological dosages of ATRA for more than 14 days and in some cases even continued to grow. These data indicate that downregulation of WT1 is essential for ATRA-induced differentiation of APL cells and provide an explanation why AML patients with high WT1 expression levels have worse overall survival in comparison to patients with low WT1 expression levels.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4247-4247
Author(s):  
Jean-Noel Bastie ◽  
Nicole Balitrand ◽  
Isabelle Guillemot ◽  
Christine Chomienne ◽  
Laurent Delva

Abstract All-trans-retinoic acid (RA) and 1alpha,25-dihydroxyvitamin D3 (1,25D3) are involved in the control of hematopoiesis and have been suggested to play a role in cellular differentiation and are as such potent inducers of differentiation of myeloid leukemia cells. In this study, we have shown that in promyelocytic NB4 cells, addition of 1,25D3 enhances terminal granulocytic RA-dependent differentiation concomitant with the enhanced activation of the RA-transcriptional activity through an RARbeta promoter. By EMSA and ChIP assays, we further demonstrate that while both VDR and RAR are bound to the RARbeta promoter in NB4 cells, addition of 1,25D3 increases VDR binding to this promoter while that of RA induces the release of VDR and increases the binding of RAR. Thus, contrary to normal myeloid cells, 1,25D3 does not act as a transrepressor of RA-transcriptional activity in leukemic cells suggesting that transcriptional regulation of RA-target genes may be modified in malignant cells. In promyelocytic leukemic cells the combination of 1,25D3 and RA results in both enhanced transactivation and differentiation.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5042-5042
Author(s):  
Pengcheng He ◽  
Mei Zhang ◽  
Jun Qi ◽  
Xiaoning Wang ◽  
Jieying Xi ◽  
...  

Abstract Although 90% patients with untreated acute promyelocytic leukemia(APL) obtain complete remission because of the usage of all-trans retinoic acid(ATRA), patients with ATRA-resistance are increased gradually. ATRA-resistance has become one of the main causes which affect the long-term therapeutic efficacy of APL. The mechanisms of ATRA-resistance are complex, which probably involve the metabolism of ATRA, abnormal expression of cellular retinoic acid binding protein(CRABP) and P-glycoprotein(P-gp), mutation of RARα and aberration translocation of APL. However, in these previous researches, it was one or a few proteins but not the entirety proteins that were emphasized on the mechanisms of ATRA-resistance. Comparative proteomics can analyze the entire protein expression in cells in whole and has the superiority in screening the drug-resistance proteins differentially expressed. In order to investigate the mechanisms of ATRA-resistance in APL in whole, we compared and analyzed the protein expression profiles between MR2 cells(APL cell line with ATRA-resistance) and NB4 cells(APL cell line with ATRA-sensitiveness) by comparative proteomics. After the total proteins of MR2 cells and NB4 cells were extracted respectively, they were separated by two-dimensional electrophoresis(2-DE). The differences in proteome profile between MR2 cells and NB4 cells analyzed by ImageMaster™ 2D Platinum software. The average protein spots in 2-DE maps of MR2 and NB4 cells were 1160±51 and 1068±33 respectively. 8 protein spots were selected to be identified by Matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF-MS), in which the quantity of the protein differentially expressed was more than two times(≥2 or ≤0.5) between MR2 and NB4 cells’ 2-DE map. They were all successfully identified and their definite information was obtained. Among them, 6 proteins were probably involved in the mechanisms of ATRA-resistance in APL and they were Cofilin-1, Elongation factor 1-beta (EF-1β), Tropomyosin isoform(TM), High mobility group protein B1(HMGB1), Ran-specific GTPase-activating protein (RanGAP1) and Galectin-1. Moreover, so far there was no related report on the roles of HMGB1, RanGAP1 and Galectin-1 in the mechanisms of ATRA-resistance in APL. These differential proteins identified provide the new clues for us to further elucidate the mechanisms of ATRA-resistance from multiple factor.


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