Histone Deacetylase Inhibitor Induces FPGS mRNA Expression in Childhood B-Precursor and T Acute Lymphoblastic Leukemia: Implication of Combination Therapy with Methotrexate To Enhance Cytotoxicity.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 864-864 ◽  
Author(s):  
Guy J. Leclerc ◽  
Julio C. Barredo

Abstract Methotrexate (MTX) is an antifolate widely used to treat childhood acute lymphoblastic leukemia (ALL). MTX is retained within cells as long-chain polyglutamates (MTX-PGs), after metabolism by the enzyme folylpoly-γ-glutamate synthetase (FPGS). Intracellular retention of MTX-PGs results in enhanced cytotoxicity due to prolonged inhibition of dihydrofolate reductase (DHFR), and the additional inhibition of thymidylate synthetase (TS). The FPGS gene was shown to be regulated by the transcription factors Sp1 and NFY. We performed DNaseI hypersensitive assays and identified a hypersensitive site mapping closely upstream of exon 1 suggesting that chromatin remodeling may contribute to FPGS gene regulation. Using co-immunoprecipitation and Western blotting we investigated the role of histone modifications and chromatin remodeling on the expression of FPGS and uncovered interactions between NFY, Sp1 and HDAC1. Our results demonstrate that HDAC1 complexes with NFY and Sp1 transcription factors in both B- and T-ALL cells. DNA affinity precipitation assay (DAPA) revealed that the HDAC1-NFY and HDAC1-Sp1 complex binds to the NFY and Sp1 binding sites in the FPGS promoter. These findings suggest that transcription of the FPGS gene may be regulated by acetylation of NFY and Sp1 factors and interaction with HDAC1, and/or chromatin remodeling. We then examined the effect of the histone deacetylase inhibitor (HDACi) sodium butyrate (NaBu) on the expression of FPGS and other folate-related genes. The level of FPGS, ATP-binding cassette subfamily C (ABCC1), ATP-binding cassette subfamily G (ABCG2), DHFR, γ-glutamyl hydrolase (GGH), solute carrier family 19/folate transporter (SLC19A1), and TS mRNA gene expression was determined by qRT-PCR in NALM6 (Bp-ALL), REH (Bp-ALL, t(12,21)/TEL-AML1), SupB15 (Bp-ALL, t(9,22)/BCR-ABL), and CCRF-CEM (T-ALL) cells treated with NaBu [2mM-5mM]. In all cell lines examined, treatment with NaBu induced 2- to 5-fold the level of FPGS and ABCC1 mRNA expression whereas the level of DHFR, SLC19A1, and TS mRNA expression was decreased. Expression of GGH and ABCG2 mRNAs was increased 2-fold in CCRF-CEM but remained unaltered in Bp-ALL NaBu treated cells. Promoters of butyrate-responsive genes have been shown to contain genetic elements such as Sp1/Sp3 binding sites which interact with HDAC1 to mediate the action of NaBu. On this basis, we hypothesized that pre-treatment of ALL cells with NaBu should lead to induction of FPGS expression and subsequently, higher synthesis of MTX-PG and enhanced MTX cytotoxicity in ALL cells. To test this hypothesis, CCRF-CEM, NALM6, REH, and SupB15 cells were treated sequentially with NaBu (24h) and MTX (4h), and assessed for cell viability. Treatment of NaBu and MTX increased cell death by ∼40% in NALM6, REH, and SupB15 Bp-cells, and ∼60% in CCRF-CCEM cells when compared to treatment with each drug alone. These data suggest that combination of HDACi and MTX may represent a novel therapeutic strategy for treatment of ALL. This strategy may be particularly useful to overcome MTX resistance in patients diagnosed with phenotypes that accumulate low levels of MTX-PGs and for patients after relapse.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2923-2923
Author(s):  
Guy J Leclerc ◽  
Caihong Mou ◽  
Gilles M Leclerc ◽  
Abdul M Mian ◽  
Julio C Barredo

Abstract Folate cofactors are essential components of one carbon metabolism and are required for the biosynthesis of purines, pyrimidines, serine and methionine. The classical folate antagonist methotrexate (MTX) continues to be a universal component of most ALL treatment regimens. MTX is retained within cells as long-chain polyglutamates (MTX-PGs) after metabolism by the enzyme folylpoly-γ -glutamate synthetase (FPGS). Intracellular retention of MTX-PGs results in enhanced cytotoxicity due to prolonged inhibition of dihydrofolate reductase (DHFR) and thymidylate synthetase (TS). The FPGS gene is regulated by the transcription factors NFY and Sp1. Using DNaseI assays we identified a hypersensitive site mapping closely upstream of exon 1, suggesting that chromatin remodeling may contribute to FPGS gene regulation. To investigate the role of histone modifications and chromatin remodeling on FPGS expression and uncover interactions between NFY, Sp1 and HDAC1, we performed co-immunoprecipitation and Western blotting. Our results demonstrate that HDAC1 complexes with NFY and Sp1 transcription factors in both B- and T-ALL cells. DNA affinity precipitation assays (DAPA) revealed that HDAC1 is recruited by NFY and Sp1 to the FPGS promoter. These findings suggest that transcription of the FPGS gene may be regulated by NFY and Sp1 factors interacting with HDAC1, and leading to chromatin remodeling. We then examined the effect of the histone deacetylase inhibitors (HDACIs) sodium butyrate (NaBu) and suberoylanilide hydroxamic acid (SAHA) on the expression of FPGS and other folate-related genes in NALM6 (Bp-ALL), REH (TEL/AML1+, Bp-ALL), SupB15 (BCR/ABL+, Bp-ALL), and CCRF-CEM (T-ALL) cells using qRT-PCR. In all cell lines examined, treatment with HDACIs increased FPGS mRNA expression by 2- to 5-fold, whereas the level of DHFR and TS mRNA expression were decreased. On this basis, we hypothesized that induction of FPGS expression by HDACIs, results in higher accumulation of MTX-PG and enhanced MTX cytotoxicity in ALL cells. Further, the concomitant decrease in the expression of the MTX-PG target enzymes DHFR and TS, would enhance the cytotoxicity of the combination of HDACIs plus MTX in ALL cells. To test this hypothesis, NALM6, REH, and SupB15 cells were treated with MTX (4h) + SAHA (24h), and cell viability assessed. We determined that SAHA increased the intracellular accumulation of long chain MTX-PGs (n ≥3 Glu) in ALL cells, correlating with the upregulation of FPGS expression in SAHA-treated cells. Treatment with MTX + SAHA increased cytotoxicity by ~30% with a calculated combination index of ≤ 0.8 indicating synergy. Analysis of apoptosis using AnnexinV/PI staining revealed a 2 to 3-fold increase in apoptotic cell death in all cell lines treated with this combination. Our data suggest HDACIs enhance MTX cytotoxicity by upregulation of FPGS expression, increased accumulation of MTXPG and downregulation of DHFR and TS. The synergism exhibited by the combination of MTX and SAHA suggests it should be tested in ALL patients, in particular those who exhibit phenotypes with de novo or acquired resistance to MTX.


Oncogene ◽  
2003 ◽  
Vol 22 (49) ◽  
pp. 7762-7773 ◽  
Author(s):  
Tohru Hirose ◽  
Yoshihiro Sowa ◽  
Senye Takahashi ◽  
Shoichi Saito ◽  
Chikako Yasuda ◽  
...  

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2418-2418 ◽  
Author(s):  
Angela Hatter ◽  
Purva Bali ◽  
Maria Balasis ◽  
Warren Fiskus ◽  
Sandhya Boyapalle ◽  
...  

Abstract We have previously reported that agents that inhibit ATP binding and chaperone function of hsp90 are highly active against wild type and mutant Bcr-Abl and mutant FLT-3 containing human acute leukemia cells. In the present studies, we determined the effects of a more soluble and potent geldanamycin analogue, DMAG (Kosan Biosciences Inc.), and/or hydroxamate histone deacetylase inhibitor (HHDI), vorinostat (Merck & Co., Inc.), against human MCL Jeko1 and MO2058 cells. These cells contain the characteristic MCL-associated chromosomal translocation t(11; 14)(q13;q32), which results in the overexpression of cyclin D1. Recently, HHDIs, such as vorinostat, have been shown to inhibit HDAC6, which results in the acetylation of hsp90 and inhibition of its ATP binding and chaperone function. Treatment with vorinostat (0.5 to 2.0 μM) induced the accumulation of the cells in the G1 and DMAG (0.1 to 0.5 μM) in the G2/M phase of the cell cycle. Both agents induced apoptosis in a dose-dependent manner (up to 50%). While vorinostat induced both p21 and p27 levels, DMAG only increased the intracellular levels of p21. Treatment with either agent depleted the intracellular levels of c-Myc, c-Raf, Akt and cdk4 in a dose dependent manner. It is well established that the chaperone association with hsp90 maintains Akt, c-Raf, cyclin D1 and cdk4 in the native and active conformation, and inhibition of hsp90 promotes their polyubiquitylation and proteasomal degradation. Notably, co-treatment with DMAG (e.g., 0.25 μM) and vorinostat (e.g., 2.0 μM), more than either agent alone, markedly attenuated the levels of cyclin D1 and cdk4, as well as the levels of c-Myc, c-Raf and Akt. The combination of DMAG and vorinostat also induced significantly more apoptosis of Jeko1 and MO2058 cells, as compared to the treatment with either agent alone (p < 0.01). These findings demonstrate that the combined treatment with vorinostat and DMAG is highly active against human MCL cells, and support the rationale to determine the in vivo efficacy and safety of the combination against human MCL.


2016 ◽  
Vol 7 (9-10) ◽  
pp. 292-300 ◽  
Author(s):  
Ying Li ◽  
Kevin Zhao ◽  
Chenjiao Yao ◽  
Samir Kahwash ◽  
Yan Tang ◽  
...  

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 56-56
Author(s):  
Irene Riz ◽  
Kristin K. Baxter ◽  
Hyo Jung Lee ◽  
Reza Behnam ◽  
Teresa S. Hawley ◽  
...  

Abstract Homeodomain proteins (homeoproteins) have long been recognized as powerful transcriptional regulators. Inappropriate expression of these transcription factors often leads to major developmental malformations or malignant transformation. The in vitro DNA binding sites of homeoproteins are short sequences that are widely distributed throughout the genome and some canonical binding sites have been shown to be functionally important at distances >20 kb away from the nearest transcription start site. In addition to DNA-binding activity, several homeoproteins have been demonstrated to interact with chromatin-modifying enzymes. For example, we and others have reported that the TLX1 homeoprotein of T-cell acute lymphoblastic leukemia (T-ALL) inhibits the PP1/PP2A serine/threonine phosphatases (I. Riz and R.G. Hawley, Oncogene 24: 5561–5575, 2005) and more recently have found that TLX1 modulates histone/transcription factor acetyltransferase CBP activity (I. Riz et al., Oncogene 26: 4115–4123, 2007). PP1/PP2A and CBP are complex molecular machines integrating diverse regulatory pathways that impact on cell survival, proliferation and differentiation outcomes. Organogenesis and malignant transformation - despite obvious differences - share a common requirement for high-order cooperativity of transcription factors and transcriptional cofactors in regulating the expression of multiple sets of genes executing cell fate shifts. Targeting key regulatory nodes in order to coordinately regulate multiple genes is a common strategy of virus induced cell-transformation: accordingly, PP1/PP2A and CBP are targeted by transforming viral proteins. The Groucho/TLE (transducin-like Enhancer-of-split) family of corepressors are another example of master regulators of cell fate; for instance, it was reported that triggering the MAPK signaling cascade inactivates TLE corepressors leading to coordinated derepression of a large number of genes involved in cell proliferation. We now demonstrate that TLX1 interferes with TLE1 repressive function. By streptavidin affinity-based precipitation of biotinylated recombinant TLX1 protein (TLX1 fused to a biotinylation peptide) we show in vivo interaction of TLX1 and TLE1 in several different cell types, including human T-ALL and neuroblastoma cells. Interaction of TLX1 with TLE1 occurs via an Engrailed homology 1 (Eh1)-like domain as documented by GST pull-down assays and laser scanning confocal microscopy. Transient transfection experiments indicate that TLX1 prevents TLE1-mediated repression of reporter genes. Furthermore, in the context of endogenous chromatin structure, TLX1 derepresses the bHLH transcription factor gene, ACSL1(HASH1), a well characterized target of the HES1/TLE1 repressor complex. The process requires direct interaction of TLX1 with TLE1 and binding of TLX1 to DNA, since a point mutation in the Eh1-like motif or deletion of the third helix of the TLX1 homeodomain abrogated the effect. Additional data to be presented suggest a long-range mechanism of transcriptional regulation by TLX1: we propose that “transcriptional activation” by TLX1 (and, by analogy, other homeoproteins that interact with TLE corepressors) results in part from the chaperoned redistribution of TLE corepressors from proximal promoter regions of target genes to distal chromatin regulatory sites.


Blood ◽  
2008 ◽  
Vol 111 (3) ◽  
pp. 1060-1066 ◽  
Author(s):  
Guillermo Garcia-Manero ◽  
Hui Yang ◽  
Carlos Bueso-Ramos ◽  
Alessandra Ferrajoli ◽  
Jorge Cortes ◽  
...  

AbstractVorinostat (suberoylanilide hydroxamic acid, SAHA) is a histone deacetylase inhibitor active clinically in cutaneous T-cell lymphoma and preclinically in leukemia. A phase 1 study was conducted to evaluate the safety and activity of oral vorinostat 100 to 300 mg twice or thrice daily for 14 days followed by 1-week rest. Patients with relapsed or refractory leukemias or myelodysplastic syndromes (MDS) and untreated patients who were not candidates for chemotherapy were eligible. Of 41 patients, 31 had acute myeloid leukemia (AML), 4 chronic lymphocytic leukemia, 3 MDS, 2 acute lymphoblastic leukemia, and 1 chronic myelocytic leukemia. The maximum tolerated dose (MTD) was 200 mg twice daily or 250 mg thrice daily. Dose-limiting toxicities were fatigue, nausea, vomiting, and diarrhea. Common drug-related adverse experiences were diarrhea, nausea, fatigue, and anorexia and were mild/moderate in severity. Grade 3/4 drug–related adverse experiences included fatigue (27%), thrombocytopenia (12%), and diarrhea (10%). There were no drug-related deaths; 7 patients had hematologic improvement response, including 2 complete responses and 2 complete responses with incomplete blood count recovery (all with AML treated at/below MTD). Increased histone acetylation was observed at all doses. Antioxidant gene expression may confer vorinostat resistance. Further evaluation of vorinostat in AML/MDS is warranted.


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