Venneti S.,University of Michigan |
Dunphy M.P.,Sloan Kettering Cancer Center |
Zhang H.,Molecular Pharmacology and Chemistry Program |
Pitter K.L.,Cancer Biology and Genetics Program |
And 16 more authors.
Science Translational Medicine | Year: 2015
Glucose and glutamine are the two principal nutrients that cancer cells use to proliferate and survive. Many cancers show altered glucose metabolism,which constitutes the basis for in vivo positron emission tomography (PET) imaging with 18F-fluorodeoxyglucose (18F-FDG). However, 18F-FDG is ineffective in evaluating gliomas because of high background uptake in the brain. Glutamine metabolism is also altered in many cancers, and we demonstrate that PET imaging in vivo with the glutamine analog 4-18F-(2S,4R)-fluoroglutamine (18F-FGln) shows high uptake in gliomas but low background brain uptake, facilitating clear tumor delineation. Chemo/radiation therapy reduced 18F-FGln tumor avidity, corresponding with decreased tumor burden. 18F-FGln uptake was not observed in animals with a permeable blood-brain barrier or neuroinflammation. We translated these findings to human subjects, where 18F-FGln showed high tumor/background ratios with minimal uptake in the surrounding brain in human glioma patients with progressive disease. These data suggest that 18F-FGln is avidly taken up by gliomas, can be used to assess metabolic nutrient uptake in gliomas in vivo, and may serve as a valuable tool in the clinical management of gliomas. Copyright © 2015 by the American Association for the Advancement of Science.
PubMed | University of Michigan, Radiochemistry and Molecular Imaging Probe Core, University of Pennsylvania, Fred Hutchinson Cancer Research Center and 8 more.
Type: Journal Article | Journal: Science translational medicine | Year: 2015
Glucose and glutamine are the two principal nutrients that cancer cells use to proliferate and survive. Many cancers show altered glucose metabolism, which constitutes the basis for in vivo positron emission tomography (PET) imaging with (18)F-fluorodeoxyglucose ((18)F-FDG). However, (18)F-FDG is ineffective in evaluating gliomas because of high background uptake in the brain. Glutamine metabolism is also altered in many cancers, and we demonstrate that PET imaging in vivo with the glutamine analog 4-(18)F-(2S,4R)-fluoroglutamine ((18)F-FGln) shows high uptake in gliomas but low background brain uptake, facilitating clear tumor delineation. Chemo/radiation therapy reduced (18)F-FGln tumor avidity, corresponding with decreased tumor burden. (18)F-FGln uptake was not observed in animals with a permeable blood-brain barrier or neuroinflammation. We translated these findings to human subjects, where (18)F-FGln showed high tumor/background ratios with minimal uptake in the surrounding brain in human glioma patients with progressive disease. These data suggest that (18)F-FGln is avidly taken up by gliomas, can be used to assess metabolic nutrient uptake in gliomas in vivo, and may serve as a valuable tool in the clinical management of gliomas.
Chau D.-M.,Molecular Pharmacology and Chemistry Program |
Chau D.-M.,Cornell University |
Shum D.,Molecular Pharmacology and Chemistry Program |
Shum D.,Sloan Kettering Cancer Center |
And 12 more authors.
Combinatorial Chemistry and High Throughput Screening | Year: 2013
The Notch pathway plays a crucial role in cell fate decisions through controlling various cellular processes. Overactive Notch signal contributes to cancer development from leukemias to solid tumors. γSecretase is an intramembrane protease responsible for the final proteolytic step of Notch that releases the membrane-tethered Notch fragment for signaling. Therefore, γsecretase is an attractive drug target in treating Notch-mediated cancers. However, the absence of high throughput γsecretase assay using Notch substrate has limited the identification and development of γ secretase inhibitors that specifically target the Notch signaling pathway. Here, we report on the development of a 1536- well γsecretase assay using a biotinylated recombinant Notch1 substrate. We effectively assimilated and miniaturized this newly developed Notch1 substrate with the AlphaLISA detection technology and demonstrated its robustness with a calculated Z' score of 0.66. We further validated this optimized assay by performing a pilot screening against a chemical library consisting of ~5,600 chemicals and identified known γsecretase inhibitors e.g. DAPT, and Calpeptin; as well as a novel γsecretase inhibitor referred to as KD-I-085. This assay is the first reported 1536-well AlphaLISA format and represents a novel high throughput Notch1-γsecretase assay, which provides an unprecedented opportunity to discover Notch-selective γsecretase inhibitors that can be potentially used for the treatment of cancer and other human disorders. © 2013 Bentham Science Publishers.
Takezawa K.,Vanderbilt Ingram Cancer Center |
Pirazzoli V.,Yale University |
Arcila M.E.,Thoracic Oncology Service |
Nebhan C.A.,Vanderbilt Ingram Cancer Center |
And 12 more authors.
Cancer Discovery | Year: 2012
EGF receptor (EGFR)-mutant lung cancers eventually become resistant to treatment with EGFR tyrosine kinase inhibitors (TKI). The combination of EGFR-TKI afatinib and anti-EGFR antibody cetuximab can overcome acquired resistance in mouse models and human patients. Because afatinib is also a potent HER2 inhibitor, we investigated the role of HER2 in EGFR -mutant tumor cells. We show in vitro and in vivo that afatinib plus cetuximab signifi cantly inhibits HER2 phosphorylation. HER2 overexpression or knockdown confers resistance or sensitivity, respectively, in all studied cell line models. FISH analysis revealed that HER2 was amplifi ed in 12% of tumors with acquired resistance versus only 1% of untreated lung adenocarcinomas. Notably, HER2 amplifi cation and EGFR T790M were mutually exclusive. Collectively, these results reveal a previously unrecognized mechanism of resistance to EGFR-TKIs and provide a rationale to assess the status and possibly target HER2 in EGFR -mutant tumors with acquired resistance to EGFR-TKIs. SIGNIFICANCE: Because all EGFR -mutant lung adenocarcinomas eventually develop resistance to TKI therapy, understanding mechanisms of acquired resistance may improve clinical outcomes. These results implicate HER2 as a novel protein involved in the sensitivity or resistance of EGFR -mutant lung cancer and provide a rationale to assess the status of and possibly target HER2 in such tumors. ©2012 AACR.
Kircher M.F.,275 York Avenue |
Gambhir S.S.,Stanford University |
Grimm J.,Molecular Pharmacology and Chemistry Program |
Grimm J.,Sloan Kettering Cancer Center
Nature Reviews Clinical Oncology | Year: 2011
Cell-based therapies, such as adoptive immunotherapy and stem-cell therapy, have received considerable attention as novel therapeutics in oncological research and clinical practice. The development of effective therapeutic strategies using tumor-targeted cells requires the ability to determine in vivo the location, distribution, and long-term viability of the therapeutic cell populations as well as their biological fate with respect to cell activation and differentiation. In conjunction with various noninvasive imaging modalities, cell-labeling methods, such as exogenous labeling or transfection with a reporter gene, allow visualization of labeled cells in vivo in real time, as well as monitoring and quantifying cell accumulation and function. Such cell-tracking methods also have an important role in basic cancer research, where they serve to elucidate novel biological mechanisms. In this Review, we describe the basic principles of cell-tracking methods, explain various approaches to cell tracking, and highlight recent examples for the application of such methods in animals and humans. © 2011 Macmillan Publishers Limited. All rights reserved.
Perna F.,Molecular Pharmacology and Chemistry Program |
Vu L.P.,Molecular Pharmacology and Chemistry Program |
Themeli M.,Molecular Pharmacology and Chemistry Program |
Kriks S.,Center for Stem Cell Biology |
And 9 more authors.
Stem Cell Reports | Year: 2015
Epigenetic regulation of key transcriptional programs is a critical mechanism that controls hematopoietic development, and, thus, aberrant expression patterns or mutations in epigenetic regulators occur frequently in hematologic malignancies. We demonstrate that the Polycomb protein L3MBTL1, which is monoallelically deleted in 20q- myeloid malignancies, represses the ability of stem cells to drive hematopoietic-specific transcriptional programs by regulating the expression of SMAD5 and impairing its recruitment to target regulatory regions. Indeed, knockdown of L3MBTL1 promotes the development of hematopoiesis and impairs neural cell fate in human pluripotent stem cells. We also found a role for L3MBTL1 in regulating SMAD5 target gene expression in mature hematopoietic cell pop-ulations, thereby affecting erythroid differentiation. Taken together, we have identified epigenetic priming of hematopoietic-specific transcriptional networks, which may assist in the development of therapeutic approaches for patients with anemia.
Minuesa G.,Molecular Pharmacology and Chemistry Program |
Minuesa G.,Center for Cell Engineering |
Antczak C.,Molecular Pharmacology and Chemistry Program |
Antczak C.,Sloan Kettering Cancer Center |
And 9 more authors.
Combinatorial Chemistry and High Throughput Screening | Year: 2014
RNA-binding proteins (RBPs) can act as stem cell modulators and oncogenic drivers, but have been largely ignored by the pharmaceutical industry as potential therapeutic targets for cancer. The MUSASHI (MSI) family has recently been demonstrated to be an attractive clinical target in the most aggressive cancers. Therefore, the discovery and development of small molecule inhibitors could provide a novel therapeutic strategy. In order to find novel compounds with MSI RNA binding inhibitory activity, we have developed a fluorescence polarization (FP) assay and optimized it for high throughput screening (HTS) in a 1536-well microtiter plate format. Using a chemical library of 6,208 compounds, we performed pilot screens, against both MSI1 and MSI2, leading to the identification of 7 molecules for MSI1, 15 for MSI2 and 5 that inhibited both. A secondary FP dose-response screen validated 3 MSI inhibitors with IC50 below 10 μM. Out of the 25 compounds retested in the secondary screen only 8 demonstrated optical interference due to high fluorescence. Utilizing a SYBR-based RNA electrophoresis mobility shift assay (EMSA), we further verified MSI inhibition of the top 3 compounds. Surprisingly, even though several aminoglycosides were present in the library, they failed to demonstrate MSI inhibitor activity challenging the concept that these compounds are pan-Active against RBPs. In summary, we have developed an in vitro strategy to identify MSI specific inhibitors using an FP HTS platform, which will facilitate novel drug discovery for this class of RBPs. © 2014 Bentham Science Publishers.
Chea E.K.,Pharmacology Program |
Fernandez-Tejada A.,Molecular Pharmacology and Chemistry Program |
Damani P.,Sloan Kettering Cancer Center |
Adams M.M.,Molecular Pharmacology and Chemistry Program |
And 4 more authors.
Journal of the American Chemical Society | Year: 2012
QS-21 is a potent immunostimulatory saponin that is currently under clinical investigation as an adjuvant in various vaccines to treat infectious diseases, cancers, and cognitive disorders. Herein, we report the design, synthesis, and preclinical evaluation of simplified QS-21 congeners to define key structural features that are critical for adjuvant activity. Truncation of the linear tetrasaccharide domain revealed that a trisaccharide variant is equipotent to QS-21, while the corresponding disaccharide and monosaccharide congeners are more toxic and less potent, respectively. Modification of the acyl chain domain in the trisaccharide series revealed that a terminal carboxylic acid is well-tolerated while a terminal amine results in reduced adjuvant activity. Acylation of the terminal amine can, in some cases, restore adjuvant activity and enables the synthesis of fluorescently labeled QS-21 variants. Cellular studies with these probes revealed that, contrary to conventional wisdom, the most highly adjuvant active of these fluorescently labeled saponins does not simply associate with the plasma membrane, but rather is internalized by dendritic cells. © 2012 American Chemical Society.
Gurvich N.,Molecular Pharmacology and Chemistry Program |
Perna F.,Molecular Pharmacology and Chemistry Program |
Farina A.,Sloan Kettering Cancer Center |
Voza F.,Molecular Pharmacology and Chemistry Program |
And 3 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2010
The l3mbtl1 gene is located on the long arm of chromosome 20 (q12), within a region commonly deleted in several myeloid malignancies. L3MBTL1 is a human homolog of the Drosophila polycomb L(3)MBT tumor suppressor protein and thus a candidate tumor suppressor in del(20q12) myeloid disorders. We used the loss-of-function approach to explore the possible tumor suppressive mechanism of L3MBTL1 and found that depletion of L3MBTL1 from human cells causes replicative stress, DNA breaks, activation of the DNA damage response, and genomic instability. L3MBTL1 interacts with Cdc45, MCM2-7 and PCNA, components of the DNA replication machinery, and is required for normal replication fork progression, suggesting that L3MBTL1 causes DNA damage, at least in part, by perturbing DNA replication. An activated DNA damage response and genomic instability are common features in tumorigenesis and a consequence of overexpression of many oncogenes. We propose that the loss of L3MBTL1 contributes to the development of 20q- hematopoietic malignancies by inducing replicative stress, DNA damage, and genomic instability.
Wang X.,Sloan Kettering Cancer Center |
Olszewska M.,Sloan Kettering Cancer Center |
Qu J.,Sloan Kettering Cancer Center |
Wasielewska T.,Sloan Kettering Cancer Center |
And 4 more authors.
Journal of Immunotherapy | Year: 2015
The successful genetic engineering of patient T cells with g-retroviral vectors expressing chimeric antigen receptors or T-cell receptors for phase II clinical trials and beyond requires the largescale manufacture of high-titer vector stocks. The production of retroviral vectors from stable packaging cell lines using roller bottles or 10-to 40-layer cell factories is limited by a narrow harvest window, labor intensity, open-system operations, and the requirement for significant incubator space. To circumvent these shortcomings, we optimized the production of vector stocks in a disposable fixed-bed bioreactor using good manufacturing practice-grade packaging cell lines. High-titer vector stocks were harvested over 10 days, representing a much broader harvest window than the 3-day harvest afforded by cell factories. For PG13 and 293Vec packaging cells, the average vector titer and the vector stocks' yield in the bioreactor were higher by 3.2-to 7.3-fold, and 5.6-to 13.1-fold, respectively, than those obtained in cell factories. The vector production was 10.4 and 18.6 times more efficient than in cell factories for PG13 and 293Vec cells, respectively. Furthermore, the vectors produced from the fixed-bed bioreactors passed the release test assays for clinical applications. Therefore, a single vector lot derived from 293Vec is suitable to transduce up to 500 patients cell doses in the context of large clinical trials using chimeric antigen receptors or T-cell receptors. These findings demonstrate for the first time that a robust fixed-bed bioreactor process can be used to produce g-retroviral vector stocks scalable up to the commercialization phase. © 2015 Wolters Kluwer Health, Inc. All rights reserved.