Englerin: Investigation of this kidney cancer-specific compound has advanced. Englerin A has excellent activity in mouse xenograft experiments. The mechanism of action has become clearer, with GLUT-1 mRNA &protein levels reduced in cells prior to a decrease in HIF-2. The action appears to fit with evolving appreciation of the importance of glycolytic pathways in kidney cancer. A Letter of Collection has been signed, permitting resupply from Tanzania &bulk isolation of englerin A. HDAC: The HDAC/DNMT inhibitor screen has identified 12 compounds with activity from the 4,363 compounds screened. The compounds are undergoing secondary &tertiary analysis of the HDAC or DNMT activity at the collaborator's lab at U. of Texas. MDM2: Screening of 148,000 natural product extracts is complete. Isolation &structural elucidation of 20 inhibitory natural products is complete. Fifteen pure compounds were identified &have been turned over by the PI for further evaluation. Three manuscripts have been published on the results. Three compounds derived from this screen &similar work with LPDS have been approved for preclinical evaluation for possible development into drug candidates for clinical trials. ABCG2: The MTDP effort has focused on publications &providing support for moving specific compounds forward in preclinical development. A publication in ACS Chemical Biology on the botryllamides, a family of natural product inhibitors has been published. Continued CCR collaboration is expected to result in further development of botryllamides, compounds from the DTP libraries, &a series of compounds from an academic collaboration. HIF2: More than 130,000 natural product extracts were screened, identifying 153 active extracts. This led to the identification of the candidaspongiolides &its core macrocycle as potent inhibitors. Work on isolating &identifying additional compounds from the active natural product extracts continues. More than 50 compounds have been isolated from marine &plant extracts &include stilbenes, flavanoids & pyrrolopyrimidines. p300: A biochemical screen has been developed using the CAD domain of HIF-1αand the CH1 domain of p300. Binding of p300 to HIF-1α is measured by fluorescence. Screening of pure compounds &natural product extract libraries has begun. TRAIL: Screening for synergistic enhancers of TRAIL activity was completed. A manuscript describing the assay was published (Cancer Immunol Immunother). Among the pure compounds identified were a group of curcurbitacins. Follow up with other members of this structural family resulted in a family of compounds with a range of activities. Assay-guided fractionation of several active natural product extracts has been completed &resulted in identification of several families of compounds, including the withanolides. Characterization of cucurbitacins &withanolides in MTDP &in the PI lab (Sayers), resulted in submission of two EIRs. AP1: Natural products chemistry on extracts active in the AP1 assay has been completed. Several families of natural products have been identified &are being characterized. One group of novel compounds appear to have specific &potent activity against NFkappaB regulated transcription. Another group appears to closely recapitulate a dominant negative c-jun mutant protein extensively characterized in the PI's lab in that they appear to inhibit both AP1 &NFkappaB. The PI's lab is planning further development of at least three groups of compounds. Natural Products Chemistry: Isolation &structural elucidation efforts focused primarily on extracts with confirmed activity in the AP-1, HIF, &TRAIL screening assays. Compounds active against the transcription factor AP-1 include lamellarin, an unusual polycyclic marine alkaloid, &a series of rotenone analogs. Structural studies on a series of terrestrial plant metabolites that potently inhibit AP-1 are ongoing. The three compounds isolated appear to have novel structures & they also inhibit NF-kapaB. Two structural classes of plant phenolic compounds were characterized that inhibit the HIF transcription factor. Assay-guided fractionation of extracts identified as active in the TRAIL assay provided a series of disulfide linked bromotyrosine derivatives from different marine sponges &hexacyclic marine alkaloid manzamine A. Piptocarphin A, a plant derived sesquiterpene lactone was also obtained as the active agent. The most potent compounds obtained that synergistically increase the cytotoxic effects of TRAIL (an apoptosis inducing ligand) were members of the withanolide family of steroidal lactones. Structure activity relationships with a series of withanolides was developed &an EIR covering the active compounds submitted. Isolation studies have begun with extracts from the tdp1 screening &a plant polyacetylenic compound has been identified as a tdp1 inhibitor. Large-scale chromatographic prefractionation of natural extracts continued at an enhanced rate. In these efforts, greater than 3000 extracts were fractionated to generate greater than 15,000 test samples. These materials have been added to our screening library for increased high throughput screening effectiveness. The installation of a new 600 MHz NMR was completed, as was the refurbishment & installation of a 500 MHz NMR spectrometer. The addition of these instruments expands the capacity &capabilities of the NMR laboratory to support isolation & structural studies. Plk1: Initial work describing the binding of the Plk1 PBD with phosphorylated pT78 peptides has led to structure base drug design of synthetic mimetic peptides (Nature Structure publication). Oxime-containing peptide libraries have been prepared &binding affinities have been tested. The complex formation of the oxime peptides with PBD is being examined by crystallography. The oxime peptides will be used as a positive controls in a HTS screen to discover inhibitors of Plk1. ER: A high content imaging system is being used to screen for ER agonists &antagonists through quantitation of ER nuclear translocation. Primary screening is complete. Over 160,000 synthetic compounds, pure natural products &natural product extracts were screened. Six are currently being evaluated in secondary assays in PI's lab. Schweinfurthin: The tumor suppressor NF1 has been shown to be altered in 20% of glioblastoma multiforme cases by the CGAP project. We show that schweinfurthin A selectivity towards CNS tumor cell lines phenocopies NF1 in NF1 deficient cells. Both glioblastoma &malignant peripheral nerve sheath tumor cell lines are sensitive to schweinfurthins. Iowa collaborators have synthesized a large number of analogs, including probes with biotin &fluorescent tags, helping elucidate schweinfurthin mechanisms. Medicinal chemistry is aimed at improving the drug-like properties of the analogs so that they can become viable drug candidates. Gp78: A cellular assay has been used to screen for inhibitors of gp78 function &ERAD, which involves ubiquitination of proteins by gp78. Natural product extracts with activity are being fractionated to isolate active principles for further characterization. NF1 in CNS Tumors Screen: A screening assay using cell lines derived from a Nf1-/+;Trp53-/+ NPcis) mouse model of astrocytoma is commencing to find agents which may have activity in CNS tumors (Reilly). The assay w [summary truncated at 7800 characters]

National Institute of Health (NIH)
National Cancer Institute (NCI)
Scientific Cores Intramural Research (ZIC)
Project #
Application #
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
National Cancer Institute Division of Basic Sciences
Zip Code
Thornburg, Christopher C; Britt, John R; Evans, Jason R et al. (2018) NCI Program for Natural Product Discovery: A Publicly-Accessible Library of Natural Product Fractions for High-Throughput Screening. ACS Chem Biol :
Bermingham, Alun; Price, Edmund; Marchand, Christophe et al. (2017) Identification of Natural Products That Inhibit the Catalytic Function of Human Tyrosyl-DNA Phosphodiesterase (TDP1). SLAS Discov :2472555217717200
Jia, Libin; Lin, Hongsheng; Oppenheim, Joost et al. (2017) US National Cancer Institute-China Collaborative Studies on Chinese Medicine and Cancer. J Natl Cancer Inst Monogr 2017:
Caropreso, Vittorio; Darvishi, Emad; Turbyville, Thomas J et al. (2016) Englerin A Inhibits EWS-FLI1 DNA Binding in Ewing Sarcoma Cells. J Biol Chem 291:10058-66
Jayatunga, Madura K P; Thompson, Sam; McKee, Tawnya C et al. (2015) Inhibition of the HIF1?-p300 interaction by quinone- and indandione-mediated ejection of structural Zn(II). Eur J Med Chem 94:509-16
O'Keefe, Barry R; Murad, André M; Vianna, Giovanni R et al. (2015) Engineering soya bean seeds as a scalable platform to produce cyanovirin-N, a non-ARV microbicide against HIV. Plant Biotechnol J 13:884-92
Dull, Angie B; George, Anuja A; Goncharova, Ekaterina I et al. (2014) Identification of compounds by high-content screening that induce cytoplasmic to nuclear localization of a fluorescent estrogen receptor ? chimera and exhibit agonist or antagonist activity in vitro. J Biomol Screen 19:242-52
Henrich, Curtis J; Budhu, Anuradha; Yu, Zhipeng et al. (2013) High-throughput screening for identification of inhibitors of EpCAM-dependent growth of hepatocellular carcinoma cells. Chem Biol Drug Des 82:131-9
Devkota, Krishna P; Wilson, Jennifer; Henrich, Curtis J et al. (2013) Isobutylhydroxyamides from the pericarp of Nepalese Zanthoxylum armatum inhibit NF1-defective tumor cell line growth. J Nat Prod 76:59-63
Masaoka, Takashi; Chung, Suhman; Caboni, Pierluigi et al. (2013) Exploiting drug-resistant enzymes as tools to identify thienopyrimidinone inhibitors of human immunodeficiency virus reverse transcriptase-associated ribonuclease H. J Med Chem 56:5436-45

Showing the most recent 10 out of 57 publications