Id1 and Id2 Are Retinoic Acid Responsive Genes and Induce a G0/G1 Arrest in Acute Promyelocytic Leukemia Cells.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2029-2029
Author(s):  
Jeannet Nigten ◽  
Gorica Nikoloski ◽  
Theo De Witte ◽  
Bert A. Van der Reijden ◽  
Joop H. Jansen
Keyword(s):  
Retinoic Acid ◽  
Dna Binding ◽  
Cell Line ◽  
Acute Promyelocytic Leukemia ◽  
Promyelocytic Leukemia ◽  
Leukemic Cells ◽  
Bhlh Transcription Factor ◽  
G1 Arrest ◽  
Granulocytic Differentiation ◽  
Bhlh Proteins

Abstract Acute promyelocytic leukemia (APL) is uniquely sensitive to treatment with all-trans retinoic acid (ATRA), which overcomes the differentiation arrest and induces terminal granulocytic differentiation of the leukemic blasts. In 98% of the cases of APL, the leukemic cells express a promyelocytic leukemia (PML)- retinoic acid receptor a (RARa) fusion protein as a result of a t(15;17) chromosome translocation. Previously, we have identified Id1 and Id2 as direct retinoic acid target genes being upregulated after ATRA stimulation in the APL cell line NB4 as well as in primary leukemic cells from APL patients. Id (inhibitor of DNA-binding) proteins act as antagonists of basic helix-loop-helix (bHLH) transcription factors by trapping them in heterodimeric complexes, thereby inhibiting DNA-binding and gene transactivation. Various bHLH proteins are pivotal in the control of differentiation and proliferation in various tissues (like muscle and nerve). We have studied the expression pattern of E2A, an ubiquitously expressed bHLH protein, which is generally considered as a promiscuous heterodimerization partner of other, more tissue restricted bHLH proteins. The expression of E2A was high in untreated APL cells and strongly downregulated upon ATRA stimulation. The simultaneous upregulation of Id1 and Id2, and the downregulation of E2A suggest a role for bHLH proteins in the induction of differentiation of APL cells upon treatment with ATRA. To assess the importance of Id1 and Id2 induction for the neutrophilic differentiation of the cells, we have overexpressed both proteins in the APL cell line NB4 using amphotropic retroviral transduction. Ectopic expression of Id1 and Id2 resulted in respectively 27% (n=3, SD= 9%) and 48% (n=3, SD=25%) inhibition of clonogenic growth in semi-solid medium, compared to vector-transduced control cells. Apart from the reduction in the number of colonies, overexpression of Id1 and Id2 did not alter the ATRA sensitivity of APL cells. NB4 liquid cultures revealed that Id1 and Id2 overexpression resulted in inhibition of proliferation and an increase of the percentage of cells in G0/G1, without having an effect on differentiation or apoptosis. These results indicate that Id1 and Id2 are important retinoic acid responsive genes in APL, and suggest that the inhibition of specific bHLH transcription factor complexes may play a role in the therapeutic effect of ATRA in APL.

AM580, a stable benzoic derivative of retinoic acid, has powerful and selective cyto-differentiating effects on acute promyelocytic leukemia cells

Blood ◽  
1996 ◽  
Vol 87 (4) ◽  
pp. 1520-1531 ◽  
Author(s):  
M Gianni ◽  
M Li Calzi ◽  
M Terao ◽  
G Guiso ◽  
S Caccia ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Cell Line ◽  
Acute Promyelocytic Leukemia ◽  
Retinoic Acid Receptor ◽  
Chromosomal Translocation ◽  
Promyelocytic Leukemia ◽  
Myelogenous Leukemia ◽  
Leukemic Cells ◽  
Stable Phase ◽  
Differentiation Markers

All-trans retinoic acid (ATRA) is successfully used in the cyto- differentiating treatment of acute promyelocytic leukemia (APL). Paradoxically, APL cells express PML-RAR, an aberrant form of the retinoic acid receptor type alpha (RAR alpha) derived from the leukemia- specific t(15;17) chromosomal translocation. We show here that AM580, a stable retinobenzoic derivative originally synthesized as a RAR alpha agonist, is a powerful inducer of granulocytic maturation in NB4, an APL-derived cell line, and in freshly isolated APL blasts. After treatment of APL cells with AM580 either alone or in combination with granulocyte colony-stimulating factor (G-CSF), the compound induces granulocytic maturation, as assessed by determination of the levels of leukocyte alkaline phosphatase, CD11b, CD33, and G-CSF receptor mRNA, at concentrations that are 10- to 100-fold lower than those of ATRA necessary to produce similar effects. By contrast, AM580 is not effective as ATRA in modulating the expression of these differentiation markers in the HL-60 cell line and in freshly isolated granulocytes obtained from the peripheral blood of chronic myelogenous leukemia patients during the stable phase of the disease. In NB4 cells, two other synthetic nonselective RAR ligands are capable of inducing LAP as much as AM580, whereas RAR beta- or RAR gamma-specific ligands are totally ineffective. These results show that AM580 is more powerful than ATRA in modulating the expression of differentiation antigens only in cells in which PML-RAR is present. Binding experiments, using COS-7 cells transiently transfected with PML-RAR and the normal RAR alpha, show that AM580 has a lower affinity than ATRA for both receptors. However, in the presence of PML-RAR, the synthetic retinoid is a much better transactivator of retinoic acid-responsive element-containing promoters than the natural retinoid, whereas, in the presence of RAR alpha, AM580 and ATRA have similar activity. This may explain the strong cyto-differentiating potential of AM580 in PML-RAR-containing leukemic cells.

1,25-Dihydroxyvitamin D3 Induces Differentiation of a Retinoic Acid–Resistant Acute Promyelocytic Leukemia Cell Line (UF-1) Associated With Expression of p21WAF1/CIP1 and p27KIP1

Blood ◽  
1999 ◽  
Vol 93 (7) ◽  
pp. 2225-2233 ◽  
Author(s):  
Akihiro Muto ◽  
Masahiro Kizaki ◽  
Kenji Yamato ◽  
Yohko Kawai ◽  
Maiko Kamata-Matsushita ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Cell Line ◽  
Acute Promyelocytic Leukemia ◽  
Northern Blot ◽  
Blot Analysis ◽  
Northern Blot Analysis ◽  
Promyelocytic Leukemia ◽  
G1 Arrest ◽  
Dihydroxyvitamin D3 ◽  
1,25 Dihydroxyvitamin D3

Retinoic acid (RA) resistance is a serious problem for patients with acute promyelocytic leukemia (APL) who are receiving all-transRA. However, the mechanisms and strategies to overcome RA resistance by APL cells are still unclear. The biologic effects of RA are mediated by two distinct families of transcriptional factors: RA receptors (RARs) and retinoid X receptors (RXRs). RXRs heterodimerize with 1,25-dihydroxyvitamin D3[1,25(OH)2D3] receptor (VDR), enabling their efficient transcriptional activation. The cyclin-dependent kinase (cdk) inhibitor p21WAF1/CIP1 has a vitamin D3–responsive element (VDRE) in its promoter, and 1,25(OH)2D3 enhances the expression of p21WAF1/CIP1 and induces differentiation of selected myeloid leukemic cell lines. We have recently established a novel APL cell line (UF-1) with features of RA resistance. 1,25(OH)2D3 can induce growth inhibition and G1 arrest of UF-1 cells, resulting in differentiation of these cells toward granulocytes. This 1,25(OH)2D3-induced G1 arrest is enhanced by all-trans RA. Also, 1,25(OH)2D3 (10−10 to 10−7 mol/L) in combination with RA markedly inhibits cellular proliferation in a dose- and time-dependent manner. Associated with these findings, the levels of p21WAF1/CIP1 and p27KIP1 mRNA and protein increased in these cells. Northern blot analysis showed that p21WAF1/CIP1 and p27KIP1 mRNA and protein increased in these cells. Northern blot analysis showed that p21WAF1/CIP1 and p27KIP1 transcripts were induced after 6 hours’ exposure to 1,25(OH)2D3 and then decreased to basal levels over 48 hours. Western blot experiments showed that p21WAF1/CIP1 protein levels increased and became detectable after 12 hours of 1,25(OH)2D3treatment and induction of p27KIP1 protein was much more gradual and sustained in UF-1 cells. Interestingly, the combination of 1,25(OH)2D3 and RA markedly enhanced the levels of p27KIP1 transcript and protein as compared with levels induced by 1,25(OH)2D3 alone. In addition, exogenous p27KIP1 expression can enhance the level of CD11b antigen in myeloid leukemic cells. In contrast, RA alone can induce G1 arrest of UF-1 cells; however, it did not result in an increase of p21WAF1/CIP1 and p27KIP1transcript and protein expression in RA-resistant cells. Taken together, we conclude that 1,25(OH)2D3 induces increased expression of cdk inhibitors, which mediates a G1 arrest, and this may be associated with differentiation of RA-resistant UF-1 cells toward mature granulocytes.

scholarly journals Retinoid-induced differentiation of acute promyelocytic leukemia involves PML-RARalpha-mediated increase of type II transglutaminase

Blood ◽  
1996 ◽  
Vol 87 (5) ◽  
pp. 1939-1950 ◽  
Author(s):  
L Benedetti ◽  
F Grignani ◽  
BM Scicchitano ◽  
AM Jetten ◽  
D Diverio ◽  
...  
Keyword(s):  
Cell Line ◽  
Signaling Pathway ◽  
Acute Promyelocytic Leukemia ◽  
Molecular Mechanisms ◽  
Growth Arrest ◽  
Promyelocytic Leukemia ◽  
Leukemic Cells ◽  
Type Ii ◽  
Granulocytic Differentiation ◽  
Nb4 Cells

All-trans retinoic acid (t-RA) administration leads to complete remission in acute promyelocytic leukemia (APL) patients by inducing growth arrest and differentiation of the leukemic clone. In the present study, we show that t-RA treatment dramatically induced type II transglutaminase (type II TGase) expression in cells carrying the t(15;17) translocation and expressing the PML-RARalpha product such as the APL-derived NB4 cell line and fresh leukemic cells from APL patients. This induction correlated with t-RA-induced growth arrest, granulocytic differentiation, and upregulation of the leukocyte adherence receptor beta subunit (CD18) gene expression. The increase in type II TGase was not abolished by cycloheximide treatment, suggesting that synthesis of a protein intermediate was not required for the induction. t-RA did not significantly alter the rate of growth arrest and did not stimulate differentiation and type II TGase activity in NB4.306 cells, a t-RA-resistant subclone of the NB4 cell line, or in leukemic cells derived from two patients morphologically defined as APL but lacking the t(15;17). However, in NB4.306 cells, t-RA treatment was able to increase CD18 mRNA expression in a manner similar to NB4 cells. The molecular mechanisms involved in the induction of these genes were investigated. In NB4 cells, using novel receptor-selective ligands such as 9-cis-RA, TTNPB, AM580, and SR11217, we found that RAR- and RARalpha- selective retinoids were able to induce growth arrest, granulocytic differentiation, and type II TGase, whereas the RXR-selective retinoid SR11217 was inactive. Moreover, an RAR alpha-antagonist completely inhibited the expression of type II TGase and CD18 induced by these selective retinoids in NB4 cells. In NB4.306 cells, an RARalpha- dependent signaling pathway was found involved in the modulation of CD18 expression. In addition, expression of the PML-RARalpha gene in myeloid U937 precursor cells resulted in the ability of these cells to induce type II TGase in response to t-RA. On the basis of these results we hypothesize a specific involvement of a signaling pathway involving PML-RAR alpha for the induction of growth arrest, granulocytic differentiation, and type II TGase by retinoids in APL cells.

scholarly journals Terminal differentiation of human promyelocytic leukemic cells in primary culture in response to retinoic acid

Blood ◽  
1981 ◽  
Vol 57 (6) ◽  
pp. 1000-1004 ◽  
Author(s):  
TR Breitman ◽  
SJ Collins ◽  
BR Keene
Keyword(s):  
Retinoic Acid ◽  
Acute Promyelocytic Leukemia ◽  
Leukemia Cell ◽  
Promyelocytic Leukemia ◽  
Leukemic Cells ◽  
Leukemia Cell Line ◽  
Granulocytic Differentiation ◽  
Myelocytic Leukemia ◽  
Functional Maturation ◽  
Promyelocytic Leukemia Cell Line

The recent finding that retinoic acid induces terminal granulocytic differentiation of the human promyelocytic leukemia cell line, HL-60, prompted an investigation of the sensitivity to this inducer of human myelocytic leukemia cells in primary suspension culture. Of the 21 leukemic specimens, only cells from the two patients with acute promyelocytic leukemia differentiated in response to retinoic acid. After an incubation period of 5--7 days in 1 microM retinoic acid, the cells from these two patients showed extensive morphological and functional maturation. Thus, because it appears that retinoic acid specifically induces granulocytic differentiation of leukemic promyelocytes, this compound may have therapeutic utility in the treatment of acute promyelocytic leukemia.

scholarly journals Retinoic acid is required for and potentiates differentiation of acute promyelocytic leukemia cells by nonretinoid agents

Blood ◽  
1994 ◽  
Vol 84 (7) ◽  
pp. 2122-2129 ◽  
Author(s):  
A Chen ◽  
JD Licht ◽  
Y Wu ◽  
N Hellinger ◽  
W Scher ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Cell Line ◽  
Acute Promyelocytic Leukemia ◽  
Drug Exposure ◽  
Primary Cultures ◽  
Leukemia Cell ◽  
Promyelocytic Leukemia ◽  
Leukemia Cell Line ◽  
Granulocytic Differentiation ◽  
Nb4 Cells

Abstract Patients with acute promyelocytic leukemia (APL) associated with the t(15;17) translocation and fusion of the promyelocytic leukemia (PML) and retinoic acid receptor-alpha (RAR-alpha) genes achieve complete remission but not cure with all-trans retinoic acid (RA), NB4, a cell line derived from a patient with t(15;17) APL that undergoes granulocytic differentiation when treated with pharmacologic doses of RA, was used as a model for differentiation therapy of APL. We found that NB4 cells are resistant to differentiation by nonretinoid inducers such as hexamethylene bisacetamide (HMBA), butyrates, vitamin D3, or hypoxanthine, all of which can induce differentiation in the commonly used HL60 leukemia cell line. Preexposure of NB4 cells to low concentrations of RA for a period as short as 30 minutes abolished resistance to nonretinoids and potentiated differentiation. Sequential RA and HMBA treatment yielded maximal differentiation by 3 days of drug exposure, whereas the effect of RA alone peaked after 6 days and yielded a smaller percentage of differentiated cells. RA also reversed NB4 cell resistance to butyrates and allowed for synergistic differentiation by these agents. Pretreatment with HMBA before exposure to RA failed to stimulate differentiation. Sequential RA/HMBA treatment also markedly increased the extent of differentiation of primary cultures of bone marrow and peripheral blood mononuclear cells from three APL patients. In one case RA/HMBA treatment overcame resistance to RA in vitro. Together, these results suggest that intermittent low doses of RA followed by either HMBA or butyrates may be a useful combination in the treatment of APL. This clinical strategy may help prevent or overcome RA resistance in APL.

Combination of retinoic acid and tumor necrosis factor overcomes the maturation block in a variety of retinoic acid-resistant acute promyelocytic leukemia cells

Blood ◽  
2004 ◽  
Vol 104 (10) ◽  
pp. 3335-3342 ◽  
Author(s):  
Michael Witcher ◽  
Hoi Ying Shiu ◽  
Qi Guo ◽  
Wilson H. Miller
Keyword(s):  
Retinoic Acid ◽  
Tumor Necrosis Factor ◽  
Cell Line ◽  
Acute Promyelocytic Leukemia ◽  
Tumor Necrosis ◽  
Promyelocytic Leukemia ◽  
Leukemia Cells ◽  
Monocytic Differentiation ◽  
Granulocytic Differentiation ◽  
Necrosis Factor

Abstract Retinoic acid (RA) overcomes the maturation block in t(15:17) acute promyelocytic leukemia (APL), leading to granulocytic differentiation. Patients receiving RA alone invariably develop RA resistance. RA-resistant cells can serve as useful models for the development of treatments for both APL and other leukemias. Previously, we showed that RA and tumor necrosis factor (TNF) promote monocytic differentiation of the APL cell line NB4 and U937 monoblastic cells. Here, we report that combining TNF with RA leads to maturation of several RA-resistant APL cells along a monocytic pathway, whereas UF-1, a patient-derived RA-resistant cell line, showed characteristics of granulocytic differentiation. We found distinct differences in gene regulation between UF-1 cells and cells showing monocytic differentiation. Although IRF-7 was up-regulated by TNF and RA in all cells tested, expression of c-jun and PU.1 correlated with monocytic differentiation. Furthermore, synergistic induction of PU.1 DNA binding and macrophage colony-stimulating factor receptor (m-CSF-1R) mRNA was observed only in cells differentiating into monocytes. Using neutralizing antibodies against m-CSF-1R or its ligand, we found that inhibiting this pathway strongly reduced CD14 expression in response to RA and TNF, suggesting that this pathway is essential for their synergy in RA-resistant leukemia cells. (Blood. 2004;104:3335-3342)

scholarly journals Retinoic acid is required for and potentiates differentiation of acute promyelocytic leukemia cells by nonretinoid agents

Blood ◽  
1994 ◽  
Vol 84 (7) ◽  
pp. 2122-2129 ◽  
Author(s):  
A Chen ◽  
JD Licht ◽  
Y Wu ◽  
N Hellinger ◽  
W Scher ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Cell Line ◽  
Acute Promyelocytic Leukemia ◽  
Drug Exposure ◽  
Primary Cultures ◽  
Leukemia Cell ◽  
Promyelocytic Leukemia ◽  
Leukemia Cell Line ◽  
Granulocytic Differentiation ◽  
Nb4 Cells

Patients with acute promyelocytic leukemia (APL) associated with the t(15;17) translocation and fusion of the promyelocytic leukemia (PML) and retinoic acid receptor-alpha (RAR-alpha) genes achieve complete remission but not cure with all-trans retinoic acid (RA), NB4, a cell line derived from a patient with t(15;17) APL that undergoes granulocytic differentiation when treated with pharmacologic doses of RA, was used as a model for differentiation therapy of APL. We found that NB4 cells are resistant to differentiation by nonretinoid inducers such as hexamethylene bisacetamide (HMBA), butyrates, vitamin D3, or hypoxanthine, all of which can induce differentiation in the commonly used HL60 leukemia cell line. Preexposure of NB4 cells to low concentrations of RA for a period as short as 30 minutes abolished resistance to nonretinoids and potentiated differentiation. Sequential RA and HMBA treatment yielded maximal differentiation by 3 days of drug exposure, whereas the effect of RA alone peaked after 6 days and yielded a smaller percentage of differentiated cells. RA also reversed NB4 cell resistance to butyrates and allowed for synergistic differentiation by these agents. Pretreatment with HMBA before exposure to RA failed to stimulate differentiation. Sequential RA/HMBA treatment also markedly increased the extent of differentiation of primary cultures of bone marrow and peripheral blood mononuclear cells from three APL patients. In one case RA/HMBA treatment overcame resistance to RA in vitro. Together, these results suggest that intermittent low doses of RA followed by either HMBA or butyrates may be a useful combination in the treatment of APL. This clinical strategy may help prevent or overcome RA resistance in APL.

scholarly journals Retinoid-induced differentiation of acute promyelocytic leukemia involves PML-RARalpha-mediated increase of type II transglutaminase

Blood ◽  
1996 ◽  
Vol 87 (5) ◽  
pp. 1939-1950 ◽  
Author(s):  
L Benedetti ◽  
F Grignani ◽  
BM Scicchitano ◽  
AM Jetten ◽  
D Diverio ◽  
...  
Keyword(s):  
Cell Line ◽  
Signaling Pathway ◽  
Acute Promyelocytic Leukemia ◽  
Molecular Mechanisms ◽  
Growth Arrest ◽  
Promyelocytic Leukemia ◽  
Leukemic Cells ◽  
Type Ii ◽  
Granulocytic Differentiation ◽  
Nb4 Cells

Abstract All-trans retinoic acid (t-RA) administration leads to complete remission in acute promyelocytic leukemia (APL) patients by inducing growth arrest and differentiation of the leukemic clone. In the present study, we show that t-RA treatment dramatically induced type II transglutaminase (type II TGase) expression in cells carrying the t(15;17) translocation and expressing the PML-RARalpha product such as the APL-derived NB4 cell line and fresh leukemic cells from APL patients. This induction correlated with t-RA-induced growth arrest, granulocytic differentiation, and upregulation of the leukocyte adherence receptor beta subunit (CD18) gene expression. The increase in type II TGase was not abolished by cycloheximide treatment, suggesting that synthesis of a protein intermediate was not required for the induction. t-RA did not significantly alter the rate of growth arrest and did not stimulate differentiation and type II TGase activity in NB4.306 cells, a t-RA-resistant subclone of the NB4 cell line, or in leukemic cells derived from two patients morphologically defined as APL but lacking the t(15;17). However, in NB4.306 cells, t-RA treatment was able to increase CD18 mRNA expression in a manner similar to NB4 cells. The molecular mechanisms involved in the induction of these genes were investigated. In NB4 cells, using novel receptor-selective ligands such as 9-cis-RA, TTNPB, AM580, and SR11217, we found that RAR- and RARalpha- selective retinoids were able to induce growth arrest, granulocytic differentiation, and type II TGase, whereas the RXR-selective retinoid SR11217 was inactive. Moreover, an RAR alpha-antagonist completely inhibited the expression of type II TGase and CD18 induced by these selective retinoids in NB4 cells. In NB4.306 cells, an RARalpha- dependent signaling pathway was found involved in the modulation of CD18 expression. In addition, expression of the PML-RARalpha gene in myeloid U937 precursor cells resulted in the ability of these cells to induce type II TGase in response to t-RA. On the basis of these results we hypothesize a specific involvement of a signaling pathway involving PML-RAR alpha for the induction of growth arrest, granulocytic differentiation, and type II TGase by retinoids in APL cells.

1,25-Dihydroxyvitamin D3 Induces Differentiation of a Retinoic Acid–Resistant Acute Promyelocytic Leukemia Cell Line (UF-1) Associated With Expression of p21WAF1/CIP1 and p27KIP1

Blood ◽  
1999 ◽  
Vol 93 (7) ◽  
pp. 2225-2233 ◽  
Author(s):  
Akihiro Muto ◽  
Masahiro Kizaki ◽  
Kenji Yamato ◽  
Yohko Kawai ◽  
Maiko Kamata-Matsushita ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Cell Line ◽  
Acute Promyelocytic Leukemia ◽  
Northern Blot ◽  
Blot Analysis ◽  
Northern Blot Analysis ◽  
Promyelocytic Leukemia ◽  
G1 Arrest ◽  
Dihydroxyvitamin D3 ◽  
1,25 Dihydroxyvitamin D3

Abstract Retinoic acid (RA) resistance is a serious problem for patients with acute promyelocytic leukemia (APL) who are receiving all-transRA. However, the mechanisms and strategies to overcome RA resistance by APL cells are still unclear. The biologic effects of RA are mediated by two distinct families of transcriptional factors: RA receptors (RARs) and retinoid X receptors (RXRs). RXRs heterodimerize with 1,25-dihydroxyvitamin D3[1,25(OH)2D3] receptor (VDR), enabling their efficient transcriptional activation. The cyclin-dependent kinase (cdk) inhibitor p21WAF1/CIP1 has a vitamin D3–responsive element (VDRE) in its promoter, and 1,25(OH)2D3 enhances the expression of p21WAF1/CIP1 and induces differentiation of selected myeloid leukemic cell lines. We have recently established a novel APL cell line (UF-1) with features of RA resistance. 1,25(OH)2D3 can induce growth inhibition and G1 arrest of UF-1 cells, resulting in differentiation of these cells toward granulocytes. This 1,25(OH)2D3-induced G1 arrest is enhanced by all-trans RA. Also, 1,25(OH)2D3 (10−10 to 10−7 mol/L) in combination with RA markedly inhibits cellular proliferation in a dose- and time-dependent manner. Associated with these findings, the levels of p21WAF1/CIP1 and p27KIP1 mRNA and protein increased in these cells. Northern blot analysis showed that p21WAF1/CIP1 and p27KIP1 mRNA and protein increased in these cells. Northern blot analysis showed that p21WAF1/CIP1 and p27KIP1 transcripts were induced after 6 hours’ exposure to 1,25(OH)2D3 and then decreased to basal levels over 48 hours. Western blot experiments showed that p21WAF1/CIP1 protein levels increased and became detectable after 12 hours of 1,25(OH)2D3treatment and induction of p27KIP1 protein was much more gradual and sustained in UF-1 cells. Interestingly, the combination of 1,25(OH)2D3 and RA markedly enhanced the levels of p27KIP1 transcript and protein as compared with levels induced by 1,25(OH)2D3 alone. In addition, exogenous p27KIP1 expression can enhance the level of CD11b antigen in myeloid leukemic cells. In contrast, RA alone can induce G1 arrest of UF-1 cells; however, it did not result in an increase of p21WAF1/CIP1 and p27KIP1transcript and protein expression in RA-resistant cells. Taken together, we conclude that 1,25(OH)2D3 induces increased expression of cdk inhibitors, which mediates a G1 arrest, and this may be associated with differentiation of RA-resistant UF-1 cells toward mature granulocytes.

scholarly journals Terminal differentiation of human promyelocytic leukemic cells in primary culture in response to retinoic acid

Blood ◽  
1981 ◽  
Vol 57 (6) ◽  
pp. 1000-1004 ◽  
Author(s):  
TR Breitman ◽  
SJ Collins ◽  
BR Keene
Keyword(s):  
Retinoic Acid ◽  
Acute Promyelocytic Leukemia ◽  
Leukemia Cell ◽  
Promyelocytic Leukemia ◽  
Leukemic Cells ◽  
Leukemia Cell Line ◽  
Granulocytic Differentiation ◽  
Myelocytic Leukemia ◽  
Functional Maturation ◽  
Promyelocytic Leukemia Cell Line

Abstract The recent finding that retinoic acid induces terminal granulocytic differentiation of the human promyelocytic leukemia cell line, HL-60, prompted an investigation of the sensitivity to this inducer of human myelocytic leukemia cells in primary suspension culture. Of the 21 leukemic specimens, only cells from the two patients with acute promyelocytic leukemia differentiated in response to retinoic acid. After an incubation period of 5--7 days in 1 microM retinoic acid, the cells from these two patients showed extensive morphological and functional maturation. Thus, because it appears that retinoic acid specifically induces granulocytic differentiation of leukemic promyelocytes, this compound may have therapeutic utility in the treatment of acute promyelocytic leukemia.

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