Inhibition of dUTPase Induces Synthetic Lethality with Thymidylate Synthase–Targeted Therapies in Non–Small Cell Lung Cancer

Wilson, Peter M.; LaBonte, Melissa J.; Lenz, Heinz‐Josef; Mack, Philip C.; Ladner, Robert D.

doi:10.1158/1535-7163.mct-11-0781

Cited by 46 publications

(52 citation statements)

References 44 publications

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“…The acute induction of TS after treatment with antifolate agents has been proposed as a mechanism of resistance to treatment. 37 In the same way, DHFR increases significantly only in PMX resistant OC cell lines. GART is not modulated or slightly up-regulated in IGROV1.…”

Section: ■ Discussionmentioning

confidence: 91%

Mass Spectrometric/Bioinformatic Identification of a Protein Subset That Characterizes the Cellular Activity of Anticancer Peptides

et al. 2014

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The preclinical study of the mechanism of action of anticancer small molecules is challenging due to the complexity of cancer biology and the fragmentary nature of available data. With the aim of identifying a protein subset characterizing the cellular activity of anticancer peptides, we used differential mass spectrometry to identify proteomic changes induced by two peptides, LR and [d-Gln(4)]LR, that inhibit cell growth and compared them with the changes induced by a known drug, pemetrexed, targeting the same enzyme, thymidylate synthase. The quantification of the proteome of an ovarian cancer cell model treated with LR yielded a differentially expressed protein data set with respect to untreated cells. This core set was expanded by bioinformatic data interpretation, the biologically relevant proteins were selected, and their differential expression was validated on three cis-platinum sensitive and resistant ovarian cancer cell lines. Via clustering of the protein network features, a broader view of the peptides' cellular activity was obtained. Differences from the mechanism of action of pemetrexed were inferred from different modulation of the selected proteins. The protein subset identification represents a method of general applicability to characterize the cellular activity of preclinical compounds and a tool for monitoring the cellular activity of novel drug candidates.

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Section: ■ Discussionmentioning

confidence: 91%

Mass Spectrometric/Bioinformatic Identification of a Protein Subset That Characterizes the Cellular Activity of Anticancer Peptides

et al. 2014

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“…Indeed, dUTPase is often overexpressed in tumors, and elevated expression of dUTPase in the nuclei of tumor cells is correlated with resistance to 5-FU-based chemotherapy in patients with metastatic colorectal cancer (8). Furthermore, siRNA-mediated knockdown of the gene encoding dUTPase (DUT) sensitizes various cancer cell lines to TS-targeted compounds, including 5-FU (9)(10)(11).…”

Section: Introductionmentioning

confidence: 99%

The 1,2-Diaminocyclohexane Carrier Ligand in Oxaliplatin Induces p53-Dependent Transcriptional Repression of Factors Involved in Thymidylate Biosynthesis

Kiyonari

Iimori

Matsuoka

et al. 2015

Molecular Cancer Therapeutics

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Platinum-based chemotherapeutic drugs are widely used as components of combination chemotherapy in the treatment of cancer. One such drug, oxaliplatin, exerts a synergistic effect against advanced colorectal cancer in combination with 5-fluorouracil (5-FU) and leucovorin. In the p53-proficient colorectal cancer cell line HCT116, oxaliplatin represses the expression of deoxyuridine triphosphatase (dUTPase), a ubiquitous pyrophosphatase that catalyzes the hydrolysis of dUTP to dUMP and inhibits dUTP-mediated cytotoxicity. However, the underlying mechanism of this activity has not been completely elucidated, and it remains unclear whether factors other than downregulation of dUTPase contribute to the synergistic effect of 5-FU and oxaliplatin. In this study, we found that oxaliplatin and dachplatin, platinum-based drugs containing the 1,2-diaminocyclohexane (DACH) carrier ligand, repressed the expression of nuclear isoform of dUTPase (DUT-N), whereas cisplatin and carboplatin did not. Oxaliplatin induced early p53 accumulation, upregulation of primary miR-34a transcript expression, and subsequent downregulation of E2F3 and E2F1. Nutlin-3a, which activates p53 nongenotoxically, had similar effects. Introduction of miR-34a mimic also repressed E2F1 and DUT-N expression, indicating that this miRNA plays a causative role. In addition to DUT-N, oxaliplatin repressed, in a p53-dependent manner, the expression of genes encoding enzymes involved in thymidylate biosynthesis. Consequently, oxaliplatin significantly decreased the level of dTTP in the dNTP pool in a p53-dependent manner. These data indicate that the DACH carrier ligand in oxaliplatin triggers signaling via the p53-miR-34a-E2F axis, leading to transcriptional regulation that ultimately results in accumulation of dUTP and reduced dTTP biosynthesis, potentially enhancing 5-FU cytotoxicity. Mol Cancer Ther; 14(10); 2332-42. Ó2015 AACR.

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“…(48) Our data are consistent with earlier reports of a direct role for uracil misincorporation in pemetrexed cytotoxicity. (49) Indeed, RNA interference-mediated silencing of dUTPase, an enzyme responsible for maintaining low dUTP levels, significantly enhances pemetrexed cytotoxicity presumably due to increased dUTP incorporation. (49) At baseline, otherwise isogenic UNG-proficient and -deficient cells have comparable levels of DNA damage markers despite reduced capacity for uracil excision suggesting UNG loss is well tolerated in the absence of TS-inhibitor challenge.…”

Section: Discussionmentioning

confidence: 99%

“…(49) Indeed, RNA interference-mediated silencing of dUTPase, an enzyme responsible for maintaining low dUTP levels, significantly enhances pemetrexed cytotoxicity presumably due to increased dUTP incorporation. (49) At baseline, otherwise isogenic UNG-proficient and -deficient cells have comparable levels of DNA damage markers despite reduced capacity for uracil excision suggesting UNG loss is well tolerated in the absence of TS-inhibitor challenge. When exposed to pemetrexed, however, UNG −/− human cancer cells accumulate up to 40-fold more uracil compared to UNG +/+ controls(20).…”

Section: Discussionmentioning

confidence: 99%

Uracil–DNA Glycosylase Expression Determines Human Lung Cancer Cell Sensitivity to Pemetrexed

Weeks

Gerson

2013

Molecular Cancer Therapeutics

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Uracil misincorporation into DNA is a consequence of pemetrexed inhibition of thymidylate synthase. The base excision repair (BER) enzyme, uracil DNA glycosylase (UNG) is the major glycosylase responsible for removal of misincorporated uracil. We previously illustrated hypersensitivity to pemetrexed in UNG−/− human colon cancer cells. Here, we examined the relationship between UNG expression and pemetrexed sensitivity in human lung cancer. We observed a spectrum of UNG expression in human lung cancer cells. Higher levels of UNG are associated with pemetrexed resistance and are present in cell lines derived from pemetrexed-resistant histological subtypes (small cell and squamous cell carcinoma). Acute pemetrexed exposure induces UNG protein and mRNA, consistent with up-regulation of uracil-DNA repair machinery. Chronic exposure of H1299 adenocarcinoma cells to increasing pemetrexed concentrations established drug-resistant sublines. Significant induction of UNG protein confirmed up-regulation of BER as a feature of acquired pemetrexed resistance. Co-treatment with the BER inhibitor, methoxyamine (MX) overrides pemetrexed resistance in chronically exposed cells, underscoring the utility of BER directed therapeutics to offset acquired drug resistance. Expression of UNG-directed siRNA and shRNA enhanced sensitivity in A549 and H1975 cells, and in drug-resistant sublines, confirming that UNG up-regulation is protective. In human lung cancer, UNG deficiency is associated with pemetrexed-induced retention of uracil in DNA that destabilizes DNA replication forks resulting in DNA double strand breaks and cell death. Thus, in experimental models, UNG is a critical mediator of pemetrexed sensitivity that warrants evaluation to determine clinical value.

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Inhibition of dUTPase Induces Synthetic Lethality with Thymidylate Synthase–Targeted Therapies in Non–Small Cell Lung Cancer

Cited by 46 publications

References 44 publications

Mass Spectrometric/Bioinformatic Identification of a Protein Subset That Characterizes the Cellular Activity of Anticancer Peptides

Mass Spectrometric/Bioinformatic Identification of a Protein Subset That Characterizes the Cellular Activity of Anticancer Peptides

The 1,2-Diaminocyclohexane Carrier Ligand in Oxaliplatin Induces p53-Dependent Transcriptional Repression of Factors Involved in Thymidylate Biosynthesis

Uracil–DNA Glycosylase Expression Determines Human Lung Cancer Cell Sensitivity to Pemetrexed

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