scholarly journals Histone deacetylase inhibitors induce FPGS mRNA expression and intracellular accumulation of long-chain methotrexate polyglutamates in childhood acute lymphoblastic leukemia: implications for combination therapy

Leukemia ◽  
2010 ◽  
Vol 24 (3) ◽  
pp. 552-562 ◽  
Author(s):  
G J Leclerc ◽  
C Mou ◽  
G M Leclerc ◽  
A M Mian ◽  
J C Barredo
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Combination Therapy ◽  
Mrna Expression ◽  
Histone Deacetylase ◽  
Histone Deacetylase Inhibitors ◽  
Lymphoblastic Leukemia ◽  
Childhood Acute Lymphoblastic Leukemia ◽  
Intracellular Accumulation ◽  
Methotrexate Polyglutamates ◽  
Long Chain

Histone Deacetylase Inhibitors Induce FPGS mRNA Expression and Intracellular Accumulation of Long-Chain Methotrexate Polyglutamates in Childhood Acute Lymphoblastic Leukemia: Implications for Combination Therapy

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2923-2923
Author(s):  
Guy J Leclerc ◽  
Caihong Mou ◽  
Gilles M Leclerc ◽  
Abdul M Mian ◽  
Julio C Barredo
Keyword(s):  
Transcription Factors ◽  
Mrna Expression ◽  
Histone Deacetylase ◽  
Cell Lines ◽  
Chromatin Remodeling ◽  
Histone Deacetylase Inhibitors ◽  
Lymphoblastic Leukemia ◽  
Intracellular Accumulation ◽  
Essential Components ◽  
Long Chain

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.

Novel SIRT1 Agonists, SRT501 and SRT2183, Induce Expression of DNA Repair Genes and Apoptosis of Ph− Acute Lymphoblastic Leukemia Cells Alone and in Combination with the HDAC Inhibitor LBH589..

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3083-3083
Author(s):  
Anna Scuto ◽  
Mark Kirschbaum ◽  
Jennifer M Cermak ◽  
Peter Atadja ◽  
Richard Jove
Keyword(s):  
Dna Damage ◽  
Acute Lymphoblastic Leukemia ◽  
Histone Deacetylase ◽  
Dna Damage Response ◽  
Histone Deacetylase Inhibitors ◽  
Lymphoblastic Leukemia ◽  
Philadelphia Chromosome ◽  
Growth Arrest ◽  
Mrna Levels ◽  
Damage Response

Abstract Abstract 3083 Poster Board III-20 Histone Deacetylase Inhibitors (HDACi) such as LBH589, which inhibit the zinc containing catalytic domain of HDAC of classes I, II, and IV, demonstrate activity against various malignancies, particularly lymphoid malignancies. SIRT1 is an NAD+ dependent class III histone deacetylase, which deacetylates histones as well as non-histone proteins and is not affected directly by HDACi such as LBH589. It remains controversial whether inhibition of SIRT1 or its activation is more efficacious in anticancer therapy. We have studied the activity of two novel SIRT1 activators, SRT501 and SRT2183, in Philadelphia chromosome negative acute lymphoblastic leukemia (ALL) cell lines. Both pre B (NALM-6, Reh) and T cell (MOLT-4) ALL lines were treated with either SRT501 or SRT2183, as well as in combination with LBH589 and evaluated for biological and gene expression responses. SRT501 induced growth arrest and apoptosis at doses ranging from 10-100 uM, with even the lowest doses inhibiting growth at 72 hours. SRT2183 is much more potent, with growth arrest and apoptosis induced at doses ranging from 1-20 uM. PCR array analysis revealed that SRT2183 treatment leads to increased mRNA levels of pro-apoptosis, growth arrest, and DNA damage response genes. We have previously demonstrated that the activity of LBH589 is mediated in part through upregulation or acetylation of proteins involved in the DNA damage response pathways. Quantitative real-time PCR confirms that the combination of LBH589 with SRT2183 leads to significantly higher expression of GADD45A and GADD45G than either agent alone. The combination of LBH589 plus SRT2183 showed enhanced inhibition of c-Myc protein levels, phosphorylation of H2A.X, and interestingly, increased acetylation of p53 (acetylation of p53 was not seen with SRT2183 alone). In summary, the novel SIRT1 activators SRT501 and SRT2183 show growth inhibitory and pro-apoptotic activity in Ph- ALL alone and enhanced activity in combination with LBH589. Clinical studies of these agents, particularly in combination with HDACi are warranted. Disclosures Kirschbaum: Novartis: Consultancy. Cermak:Sirtris: Employment. Atadja:Novartis: Employment.

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
Keyword(s):  
Transcription Factors ◽  
Acute Lymphoblastic Leukemia ◽  
Mrna Expression ◽  
Histone Deacetylase ◽  
Chromatin Remodeling ◽  
Binding Sites ◽  
Histone Deacetylase Inhibitor ◽  
Lymphoblastic Leukemia ◽  
Atp Binding ◽  
Deacetylase Inhibitor

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.

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