Ecteinascidin 743 (Et743) is a novel anticancer agent presently in Phase II/III clinical trials. Responses have been observed in sarcomas, which is very interesting because these poor prognosis tumors are notoriously resistant to previously used treatments. Et743 (NSC 648766) differs from other anticancer drugs in clinical use because it forms covalent adducts at specific guanines in the minor groove of DNA and because it selectively block transcription of genes containing transcription factors that bind to guanine-rich sequences (such as NF-Y transcription factor). To further elucidate the mechanism of action of Et743, we have generated an Et743-resistant cell line (HCT116/ER5). The HCT116/ER5 cells exhibit enhanced microsatellite instability and aneuploidy. Complete lack of expression of the DNA repair gene XPG was found in HCT116/ER5 cells as a result of chromosome 13q DNA copy-number loss, due to an unbalanced t(13; 14) translocation, and loss of heterozygosity at 13q33.3, due to a frameshift mutation of XPG at codon 240 resulting in a stop codon at position 243. Transfection of XP-G cDNA restored the sensitivity of the HCT116/ER5 cells to Et743 demonstrating that proteins involved in the nucleotide excision repair pathway such as the endonuclease XPG are essential for the antiproliferative activity Et743. Xeroderma pigmentosum cells deficient in the NER genes XPG, XPA, XPD, or XPF were resistant to Et743, and sensitivity was restored by complementation with wild-type genes. Moreover, studies of cells deficient in XPC or in the Cockayne Syndrome genes (CSA and CSB) indicated that the drug sensitivity is dependent specifically on the transcription-coupled pathway of NER. Thus, we found that Et743 interacts with the transcription-coupled NER machinery to induce lethal DNA strand breaks. Et743 defines a novel class of anticancer drugs in which enhanced antiproliferative activity parallels enhanced cellular DNA-repair capability. Because most cancers have alterations in the cell cycle checkpoint pathways (p53, pRb) and cell cycle machinery (cyclins, cyclin-dependent kinase inhibitors - such as p16), we are exploring inhibitors of cell cycle checkpoints as novel anticancer agents. 7-hydroxystaurosporine (UCN-01) is a novel anticancer agent in phase II/III clinical trials. We found that UCN-01 is synergistic with DNA damaging agents such as topoisomerase inhibitors and drugs that act during the S-phase of the cell cycle. This synergism has been related to an abrogation of the S-phase checkpoint, which is controlled by 2 protein kinases, Chk1 and Chk2. UCN-01 was found to inhibit Chk1 and we are examining the effects of UCN-01 on Chk2 and the role of Chk2 in cell cycle checkpoint in cancer cells.

Agency
National Institute of Health (NIH)
Institute
Division of Basic Sciences - NCI (NCI)
Type
Intramural Research (Z01)
Project #
1Z01BC006150-20
Application #
6558978
Study Section
(LMP)
Project Start
Project End
Budget Start
Budget End
Support Year
20
Fiscal Year
2001
Total Cost
Indirect Cost
Name
Basic Sciences
Department
Type
DUNS #
City
State
Country
United States
Zip Code
Yu, Le-Mao; Hu, Zhu; Chen, Yu et al. (2018) Synthesis and structure-activity relationship of furoquinolinediones as inhibitors of Tyrosyl-DNA phosphodiesterase 2 (TDP2). Eur J Med Chem 151:777-796
Tang, Sai-Wen; Thomas, Anish; Murai, Junko et al. (2018) Overcoming Resistance to DNA-Targeted Agents by Epigenetic Activation of Schlafen 11 (SLFN11) Expression with Class I Histone Deacetylase Inhibitors. Clin Cancer Res 24:1944-1953
Murai, Junko; Tang, Sai-Wen; Leo, Elisabetta et al. (2018) SLFN11 Blocks Stressed Replication Forks Independently of ATR. Mol Cell 69:371-384.e6
Lee, Hee-Sheung; Carmena, Mar; Liskovykh, Mikhail et al. (2018) Systematic Analysis of Compounds Specifically Targeting Telomeres and Telomerase for Clinical Implications in Cancer Therapy. Cancer Res 78:6282-6296
Kiselev, Evgeny; Dexheimer, Thomas S; Marchand, Christophe et al. (2018) Probing the evolutionary conserved residues Y204, F259, S400 and W590 that shape the catalytic groove of human TDP1 for 3'- and 5'-phosphodiester-DNA bond cleavage. DNA Repair (Amst) 66-67:64-71
Huang, Shar-Yin N; Dalla Rosa, Ilaria; Michaels, Stephanie A et al. (2018) Mitochondrial tyrosyl-DNA phosphodiesterase 2 and its TDP2S short isoform. EMBO Rep 19:
Tsuda, Masataka; Terada, Kazuhiro; Ooka, Masato et al. (2017) The dominant role of proofreading exonuclease activity of replicative polymerase ? in cellular tolerance to cytarabine (Ara-C). Oncotarget 8:33457-33474
Bruno, Peter M; Liu, Yunpeng; Park, Ga Young et al. (2017) A subset of platinum-containing chemotherapeutic agents kills cells by inducing ribosome biogenesis stress. Nat Med 23:461-471
Al Abo, Muthana; Sasanuma, Hiroyuki; Liu, Xiaojun et al. (2017) TDP1 is Critical for the Repair of DNA Breaks Induced by Sapacitabine, a Nucleoside also Targeting ATM- and BRCA-Deficient Tumors. Mol Cancer Ther 16:2543-2551
Thomas, Anish; Tanaka, Mamoru; Trepel, Jane et al. (2017) Temozolomide in the Era of Precision Medicine. Cancer Res 77:823-826

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