Histone deacetylase inhibitor enhances 5-fluorouracil cytotoxicity by down-regulating thymidylate synthase in human cancer cells

Lee, Ju Hee; Park, Jung Hyun; Jung, Yeonjoo; Kim, Jee Hyun; Jong, Hyun Soon; Kim, Tae You; Bang, Yung Jue

doi:10.1158/1535-7163.mct-06-0419

Cited by 94 publications

(82 citation statements)

References 43 publications

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“…Moreover, in agreement with previous reports, 14,15 we demonstrated that TS protein expression was downmodulated in time-dependent manner by vorinostat in wild-type p53 (wt-p53) LoVo and LS174T as well as in mut-p53 HT29 and SW620, cell lines. In details, a clear downregulation of TS expression was evident between 6-12 h in all cell lines with almost undetectable levels of the corresponding band observed thereafter in some cell lines (Fig.…”

Section: Resultssupporting

confidence: 93%

“…Previous studies, demonstrated that TS mRNA and protein are both downregulated by HDAC-I through two independent mechanisms: at the transcriptional level and through modulation of protein degradation by a mechanism involving acetylation of the chaperone protein Hsp90. 14,15 Moreover, in our study we demonstrated that p53 protein, whose functional wild-type expression is critical for drug sensitivity to TS inhibitors such as 5FU and RTX, 35 is upregulated by vorinostat in wt-p53 cells but downregulated in mut-p53 cells, as single agent or in combination treatment. It as been previously reported that p53 protein acetylation, upon HDAC inhibition, is essential for preventing the degradation and for leading to an open conformation that allowed the protein to bind DNA.…”

Section: Methodsmentioning

confidence: 58%

“…Recent studies demonstrated that HDAC-Is can potentiate 5FU-induced inhibition of cell growth in colon and gastric cancer cells. 14,16 However, at least to our knowledge, our study is the first to demonstrate a synergistic effect of an HDAC-I such as vorinostat in combination with the pure inhibitor of TS RTX and with 5FU bio-modulated by FA (5FU-FA), the latter being the cornerstone of chemotherapy regimens in the colorectal cancer. We also provided evidences demonstrating that the mechanism of the synergistic interaction observed lay in the modulation of both TS and p53 protein expression.…”

Section: In Vitro Synergism Of Vorinostat Plus Ts-inhibitorsmentioning

confidence: 83%

“…4,9,13 Several reports, including microarray studies, have shown that the expression of the enzyme thymidilate synthase (TS) can be regulated by HDAC-Is. [14][15][16] In details, Glaser et al have shown that different HDAC-Is may control the expression of a "core" set of genes, eight upregulated and five downregulated, including TS, in several cell lines. 15 TS is an essential enzyme for the de novo synthesis of thymidilate (dTMP) and subsequently DNA synthesis, and is a critical target for 5FU and RTX.…”

Section: Introductionmentioning

confidence: 99%

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Modulation of thymidilate synthase and p53 expression by HDAC inhibitor vorinostat resulted in synergistic antitumor effect in combination with 5FU or Raltitrexed

Gennaro¹,

Bruzzese²,

Pepe³

et al. 2009

Cancer Biology & Therapy

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Despite the introduction of several novel anticancer agents almost 50% of colorectal cancer (CRC) patients die for cancer suggesting the necessity of new therapeutical approaches. In this study we demonstrated that the HDAC inhibitor vorinostat exerted potent antiproliferative effect in a panel of mut-and wt-p53 human CRC cell lines. Moreover, in combination with 5-fluorouracil modulated by folinic acid (5FU-FA) or with Raltitrexed (RTX), both commonly used in the treatment of this disease, it showed a clear schedule-dependent synergistic antiproliferative interaction as demonstrated by calculating combination indexes. Only simultaneous, or 24 h pretreatment with vorinostat followed by either agent, produced synergistic effect paralleled by evident cell cycle perturbations with major S-phase arrest. Moreover, we provided for the first time evidences that vorinostat can overcome resistance to both 5FU and RTX. Downmodulation of Thymidilate synthase (TS) protein induced by vorinostat within 24 h, represented a key factor in enhancing the effects of both drugs in sensitive as well as resistant tumor cells. Furthermore, p53, whose wildtype expression is critical for sensitivity to 5FU and RTX, was upregulated by vorinostat in wt-and downregulated in mut-p53 cells, suggesting an additional mechanism of the antiproliferative synergistic interactions observed. Overall these data add new insights in the mechanism of vorinostat antitumor effect and suggested that the association of vorinostat plus 5FU-FA and/or RTX should be clinically explored.

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Section: Resultssupporting

confidence: 93%

Section: Methodsmentioning

confidence: 58%

Section: In Vitro Synergism Of Vorinostat Plus Ts-inhibitorsmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modulation of thymidilate synthase and p53 expression by HDAC inhibitor vorinostat resulted in synergistic antitumor effect in combination with 5FU or Raltitrexed

Gennaro¹,

Bruzzese²,

Pepe³

et al. 2009

Cancer Biology & Therapy

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“…Consistent with our data, HDACIs (trichostatin-A and SAHA) were recently reported to downregulate TS and overcome 5-fluorouracil resistance in models of gastrointestinal malignancy. 53,54 Alternatively, the observed downregulation of TS and DHFR in ALL cell lines treated with SAHA or NaBu could result from the observed cell-cycle arrest induced by these agents rather than a direct effect on gene expression. Since no significant difference was found in the level of GGH mRNA expression and both FPGS and GGH activities determine the intracellular metabolism to MTX-PGs, we conclude that once MTX is inside the cells, accumulation of MTX-PGs is exclusively dependent on FPGS expression in cells treated with HDACIs.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2010

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Children with acute lymphoblastic leukemia (ALL) diagnosed with resistant phenotypes, and those who relapse, have a dismal prognosis for cure. The antifolate methotrexate (MTX), a universal component of ALL therapies, is metabolized by folylpoly-c-glutamate synthetase (FPGS) into long-chain polyglutamates (MTX-PG 3À7 ), resulting in enhanced cytotoxicity from prolonged inhibition of dihydrofolate reductase (DHFR) and thymidylate synthetase (TS). Using DNaseI assays, we identified a hypersensitive site upstream from exon-1, suggesting chromatin remodeling could alter FPGS expression. We demonstrated that histone deacetylase-1 (HDAC1) is recruited by NFY and Sp1 transcription factors to the FPGS promoter in ALL cell lines. We examined the effect of histone deacetylase inhibitors (HDACIs) sodium butyrate and suberoylanilide hydroxamic acid (SAHA) on the expression of FPGS and other folate-related genes. HDACIs increased FPGS mRNA expression by 2-to 5-fold, whereas DHFR and TS mRNA expression was decreased. Combination treatment with MTX plus SAHA significantly increased cytotoxicity and apoptosis in B-and T-ALL cell lines as compared with each drug alone (CIp0.8). SAHA increased the intracellular accumulation of long-chain MTX-PG 3À7 . Therefore, HDACI-induced FPGS expression increases the accumulation of MTX-PG 3À7 and cytotoxicity in ALL cell lines, which is potentiated by DHFR and TS downregulation. The synergism exhibited by the combination of MTX and SAHA warrants clinical testing in ALL patients.

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Histone deacetylase inhibitors suppress thymidylate synthase gene expression and synergize with the fluoropyrimidines in colon cancer cells

Fazzone

Wilson

LaBonte

et al. 2009

Intl Journal of Cancer

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Despite recent therapeutic advances, the response rates to chemotherapy for patients with metastatic colon cancer remain at 50% with the fluoropyrimidine, 5-fluorouracil (5-FU), continuing to serve as the foundation chemotherapeutic agent for the treatment of this disease. Previous studies have demonstrated that overexpression of thymidylate synthase (TS) is a key determinant of resistance to 5-FU-based chemotherapy. Therefore, there is a significant need to develop alternative therapeutic strategies to overcome TS-mediated resistance. In this study, we demonstrate that the histone deacetylase inhibitors (HDACi) vorinostat and LBH589 significantly downregulate TS gene expression in a panel of colon cancer cell lines. Downregulation of TS was independent of p53, p21 and HDAC2 expression and was achievable in vivo as demonstrated by mouse xenograft models. We provide evidence that HDACi treatment leads to a potent transcriptional repression of the TS gene. Combination of the fluoropyrimidines 5-FU or FUdR with both vorinostat and LBH589 enhanced cell cycle arrest and growth inhibition. Importantly, the downstream effects of TS inhibition were significantly enhanced by this combination including the inhibition of acute TS induction and the enhanced accumulation of the cytotoxic nucleotide intermediate dUTP. These data demonstrate that HDACi repress TS expression at the level of transcription and provides the first evidence suggesting a direct mechanistic link between TS downregulation and the synergistic interaction observed between HDACi and 5-FU. This study provides rationale for the continued clinical evaluation of HDACi in combination with 5-FU-based therapies as a strategy to overcome TS-mediated resistance. ' UICCKey words: colon cancer; thymidylate synthase; histone deacetylase inhibitors; fluoropyrimidines; 5-fluorouracil; vorinostat; LBH589 For over 50 years, the fluoropyrimidine class of anticancer agents such as 5-fluorouracil (5-FU) have served as the foundation for the treatment of colon cancer. Chemotherapy-based approaches for the treatment of colon cancer have improved significantly in recent years with 5-FU used in combination with newer agents such as oxaliplatin, irinotecan, cetuximab and bevacizumab. These combinations now demonstrate response rates up to 50%. [1][2][3] However, the clinical efficacy of these treatments is hindered due to intrinsic or acquired drug resistance, and novel strategies to overcome resistance are of great clinical importance.Fluoropyrimidines such as 5-FU and FUdR induce cellular toxicity by inhibiting the enzyme thymidylate synthase (TS) and by incorporating fluoronucleotides into RNA and DNA. The TS enzyme converts dUMP to TMP and serves as the sole de novo source of thymidylate and is essential for DNA synthesis. 5-FU inhibits TS by the formation of a stable ternary complex consisting of the 5-FU metabolite fluorodeoxyuridine monophosphate (FdUMP), the folate cofactor 5,10-methylene tetrahydrofolate, and the TS enzyme leading to thymidylate depletion, cell cycle ...

show abstract

Histone deacetylase inhibitor enhances 5-fluorouracil cytotoxicity by down-regulating thymidylate synthase in human cancer cells

Cited by 94 publications

References 43 publications

Modulation of thymidilate synthase and p53 expression by HDAC inhibitor vorinostat resulted in synergistic antitumor effect in combination with 5FU or Raltitrexed

Modulation of thymidilate synthase and p53 expression by HDAC inhibitor vorinostat resulted in synergistic antitumor effect in combination with 5FU or Raltitrexed

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

Histone deacetylase inhibitors suppress thymidylate synthase gene expression and synergize with the fluoropyrimidines in colon cancer cells

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