tbuckley/cabot-search huggingface dataset:
Abstract 4173: Drug target mutations as a mechanism of acquired resistance to small molecules activators of protein phosphatase 2a
Authors: Rita Tohme, Jaya Sangodkar, Janna Kiselar, Daniel Leonard, Caitlin O'Connor, Sai Gandhe, Wenqing Xu, David Brautigan, Mark Chance, Michael Ohlmeyer, Goutham Narla
Journal: Cancer Research (2017)

Abstract The sustainable activation of the RAS/MAPK and PI3K/AKT signaling pathways in cancer is promoted by a reduction in the activity of the tumor suppressor protein phosphatase 2A (PP2A). Therefore, a novel therapeutic strategy consists of directly activating PP2A, leading to the simultaneous inhibition of these oncogenic pathways. PP2A is a heterotrimeric complex, consisting of a scaffolding A subunit, catalytic C subunit, and one of many regulatory B subunits responsible for substrate specificity. Our lab has successfully developed first-in-class Small Molecule Activators of PP2A (SMAPs), which induce tumor growth inhibition in both transgenic and patient derived xenograft mice models. However, alterations to the drug binding site is one of the most common mechanisms of acquired resistance, and we hypothesized that point mutations of the drug binding amino acid residues of PP2A would lead to decreased sensitivity to SMAP treatment. Determining potential mechanisms responsible for the development of resistance to SMAPs would guide the development of novel therapeutic strategies to improve patients’ prognosis. In silico docking calculations, photo affinity labeling, and hydroxyl radical footprinting studies were used to identify K194, E197, and L198 as the putative residues of PP2A-Aα that were interacting with SMAPs. K194R, E197K, and L198V mutations were generated by site-directed mutagenesis. H358, a KRAS-driven lung adenocarcinoma cell line, was used to create isogenic cell lines stably overexpressing mutated and wild type PP2A-Aα. These mutations did not affect the phosphatase activity or its ability to form holoenzymes in a cell-free system. SMAP response was investigated in vivo using a xenograft model of H358 isogenic cell lines and it was determined that tumors harboring mutant K194R and L198V PP2A-Aα were resistant to SMAPs treatment. Together, our results suggest that residues K194 and L198 are required for drug binding and subsequent target engagement. These findings shed light on possible mechanisms of acquired resistance to SMAPs in patients and have potential to guide the design of second-generation drugs. Citation Format: Rita Tohme, Jaya Sangodkar, Janna Kiselar, Daniel Leonard, Caitlin O'Connor, Sai Gandhe, Wenqing Xu, David Brautigan, Mark Chance, Michael Ohlmeyer, Goutham Narla. Drug target mutations as a mechanism of acquired resistance to small molecules activators of protein phosphatase 2a [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4173. doi:10.1158/1538-7445.AM2017-4173
Abstract 5267: Chemoprevention of lung carcinogenesis by dietary nicotinamide and inhaled budesonide
Authors: Donna Seabloom, Beverly Wuertz, Art Galbraith, Jenny Antonides, Vernon Steele, Lee Wattenberg, Frank G. Ondrey
Journal: Cancer Research (2017)

Abstract Nicotinamide, the amide form of vitamin B3, and budesonide, a synthetic glucocorticoid used in the treatment of asthma, were evaluated for efficacy of chemoprevention of lung adenoma formation in a benzo(a)pyrene murine carcinogenesis model. Female A/J mice were given three doses of 3 mg benzo[a]pyrene three days apart and started on experimental diets either 1 week (early stage intervention) or 8 weeks (late stage) after last carcinogen dose. Aerosol treatments were delivered 5 days per week starting 1 or 8 weeks post carcinogen. Nicotinamide, fed at a dietary concentration of 0.75% starting 1 week after last carcinogen administration, inhibited adenoma formation by 54%, and by 39% when begun 8 weeks post final carcinogen. Nicotinamide fed at 0.25% of the diet was not found to effect adenoma formation . Dietary nicotinamide under the same conditions with budesonide administered via aerosol administration at 25μg/kg, reduced lung adenoma formation by 90% at early stage intervention and 49% at late stage intervention. Budesonide alone administered at the same dose level gave 77% inhibition at early stage and 41% inhibition at late stage. Decreases in adenoma formation were statistically significant via ANOVA analysis at both early and late interventions. Combination therapy decreased adenoma formation significantly over either individual therapy at the early stage and significantly compared to nicotinamide alone at the late stage. However, administration of nicotinamide by aerosol inhalation at doses up to 15 mg/kg/day did not result in a statistically significant reduction in tumor multiplicity at 1 or 8 weeks post last carcinogen administration . There is a high level of clinical interest in minimal toxicity lung cancer chemoprevention strategies. We feel administration of a safe dietary agent such as nicotinamide when combined with direct epithelial delivery of a glucocorticoid such as budesonide, commonly used for asthma therapy, is a promising approach for aerodigestive chemoprevention. Citation Format: Donna Seabloom, Beverly Wuertz, Art Galbraith, Jenny Antonides, Vernon Steele, Lee Wattenberg, Frank G. Ondrey. Chemoprevention of lung carcinogenesis by dietary nicotinamide and inhaled budesonide [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5267. doi:10.1158/1538-7445.AM2017-5267
Abstract 4948: Characterization of hTERT-immortalized prostate-derived stromal and epithelial cells: An authenticin vitromodel for tumor microenvironment studies
Authors: Luis G. Rodriguez, Russell E. McDaniel, Xiangshan Zhao, Elizabeth Turner, Christopher Annesi, Chaozhong Zou
Journal: Cancer Research (2017)

Abstract Tumor development begins with mutational changes to the genetic makeup of a cell, but its progression is not solely determined by the mutated cell, but also by the tumor’s microenvironment. Prostate cancer, a leading cancer diagnosed in men, has been shown to be highly influenced by its surrounding stroma, particularly fibroblasts. It has been demonstrated that cancer-associated prostate fibroblast (CAFs) differ from normal-associated prostate fibroblast (NAFs). However, human prostate cancer model systems have focused largely on prostate cancer epithelial cells. Currently, a need exists for a more physiologically relevant human cell model system to study prostate cancer progression within the context of its tumor microenvironment. In this study, we characterized three prostate-derived cells: prostate cancer-associated fibroblast (CAFs), prostate normal-associated fibroblast (NAFs) and prostate cancer epithelial (PrE) cells; all three lines were immortalized by hTERT (human telomerase reverse transcriptase) alone, and have been continuously passaged for more than 40 PDL in our hands. Our data shows that the hTERT immortalized CAFs proliferate faster than the NAFs; in addition, both CAFs and NAFs express fibroblast markers such as TE7 and alpha smooth muscle actin (α-SMA), while neither cell line expresses epithelial marker such as CK14. Both CAFs and NAFs also express elevated levels of α-SMA upon TGF-β stimulation. All three prostate-derived cells express the prostate specific marker AR, and show similar markers staining after long time passaging. Importantly, conditioned media collected from CAFs promotes tumor cell growth better than NAF conditioned media. In conclusion, CAFs, NAFs, and immortalized prostate cancer epithelium may provide a very valuable model system for the study of prostate cancer cell progression and tumor microenvironment studies. Citation Format: Luis G. Rodriguez, Russell E. McDaniel, Xiangshan Zhao, Elizabeth Turner, Christopher Annesi, Chaozhong Zou. Characterization of hTERT-immortalized prostate-derived stromal and epithelial cells: An authentic in vitro model for tumor microenvironment studies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4948. doi:10.1158/1538-7445.AM2017-4948
Abstract 5485: The combined effects of polyamine and GSH inhibition on the viability of human cancer cell lines
Authors: John Grady, Davey Holzer, Kaci Keleher, Emma Meetz, Russ Feirer
Journal: Cancer Research (2017)

Abstract Polyamines play essential roles in DNA stability and cell proliferation, making polyamine metabolism a potential target for cancer therapeutics. The spermine analog N1,N11- Diethylnorspermine (DenSpm) reduces levels of ODC, the enzyme responsible for polyamine biosynthesis, and also induces the enzyme SSAT, responsible for the catabolism of polyamines. Polyamines have been shown to inactivate reactive oxygen species (ROS), including peroxides, protecting mammalian cells from oxidative damage to nucleic acids. The catabolism of polyamines by SSAT, in contrast, leads to the production of ROS, which results in cellular death and limits the progression of cancer. Buthionine sulfoximine (BSO) selectively depletes stores of intracellular glutathione GSH, an antioxidant that neutralizes ROS. We hypothesized that treating cancer cell lines with both DenSpm and BSO will have a synergistic cytotoxic effect on the cells, due to the depletion of ROS-scavenging polyamines, the generation of ROS caused by DenSpm and the absence of GSH. Treatment of the four cell lines, MCF-7, MDA-MD-231, Caco-2 and PANC-1, with DenSpm resulted in moderate reductions in cell viability as measured using the Cell Titer Blue assay (Promega, Inc.). As has been widely reported in other mammalian systems, DenSpm (10 µM) reduced intracellular polyamine concentrations (HPLC of benzoylated polyamine derivatives) and induced SSAT (Western Blots). Treatment of cells with BSO (500 µM) caused a significant decrease in intracellular GSH levels. Similar findings have been reported in previous studies with human neuroblastoma lines (Anderson, et al. 1999). The combination of BSO and DenSpm had effects markedly greater than either compound alone. Pretreatment of cells with BSO (500 µM) for 24 hours with subsequent removal of BSO before DenSpm (10, 100, 1000 µM) addition resulted in significantly reduced viability in all cell lines. DenSpm was found to be most effective in the continued presence of BSO as compared to a 24-hour BSO pretreatment. The compounds used in combination also enhanced ROS production, further demonstrating their synergistic effects. Citation Format: John Grady, Davey Holzer, Kaci Keleher, Emma Meetz, Russ Feirer. The combined effects of polyamine and GSH inhibition on the viability of human cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5485. doi:10.1158/1538-7445.AM2017-5485
A Phase 2 Study of Lenalidomide to Repair Immune Synapse Response and Humoral Immunity in Early-Stage, Asymptomatic Chronic Llmphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL) with High-Risk Genomic Features
Authors: Jeffrey A. Jones, Amy J. Johnson, Farrukh T. Awan, Quihong Zhao, Natarajan Muthusamy, Kami J. Maddocks, Leslie A. Andritsos, Kerry A. Rogers, Jennifer A. Woyach, Gerard Lozanski, Nyla A. Heerema, Cathy Brookfield, Amy S Ruppert, John C. Byrd
Journal: Blood (2016)
Abstract LB-056: Quantitative mass spectrometry analysis of immune checkpoint protein expression and N-glycosylation in human melanoma
Authors: Carlos Morales Betanzos, Hyoungjoo Lee, Paula I. Gonzalez Ericsson, Justin M. Balko, Douglas B. Johnson, Lisa J. Zimmerman, Daniel C. Liebler
Journal: Cancer Research (2017)

Abstract Quantitative assessment of key proteins that control the tumor-immune interface is one of the most formidable analytical challenges in immunotherapeutics. We developed an targeted mass spectrometry (MS) platform to quantify programmed cell death-1 (PD-1), programmed cell death 1 ligand 1 (PD-L1), and programmed cell death 1 ligand 2 (PD-L2) at fmol/microgram protein levels in formalin fixed, paraffin-embedded sections from 22 human melanomas. PD-L1 abundance ranged 50-fold, from approximately 0.03 to 1.5 fmol/microgram protein and the PRM data were largely concordant with total PD-L1-positive cell content, as analyzed by immunohistochemistry (IHC) with the E1L3N antibody. PD-1 was measured at levels up to 20-fold lower than PD-L1, but the abundances were not significantly correlated (r2 = 0.062, p = 0.264). PD-1 abundance was weakly correlated (r2 = 0.3057, p = 0.009) with the fraction of lymphocytes/histiocytes in sections. PD-L2 was measured from 0.03 to 1.90 fmol/microgram protein and the ratio of PD-L2 to PD-L1 abundance ranged from 0.03 to 2.58. In 8 samples, PD-L2 was present at more than half the level of PD-L1, which suggests that PD-L2, a higher affinity PD-1 ligand, is sufficiently abundant to contribute to T-cell downregulation. We also identified five branched mannose and N-acetylglucosamine glycans at PD-L1 position N192 in all 22 samples. Extent of PD-L1 glycan modification varied by approximately 10-fold and the melanoma with the highest PD-L1 protein abundance and most abundant glycan modification yielded a very low PD-L1 IHC estimate, thus suggesting that N-glycosylation may affect IHC measurement and PD-L1 function. Additional PRM analyses quantified immune checkpoint/co-regulator proteins LAG3, IDO1, TIM-3, VISTA and CD40, which all displayed distinct expression independent of PD-1, PD-L1 and PD-L2. Targeted MS can provide a next-generation analysis platform to advance cancer immuno-therapeutic research and diagnostics. (Supported by NIH grant U24CA159988) Citation Format: Carlos Morales Betanzos, Hyoungjoo Lee, Paula I. Gonzalez Ericsson, Justin M. Balko, Douglas B. Johnson, Lisa J. Zimmerman, Daniel C. Liebler. Quantitative mass spectrometry analysis of immune checkpoint protein expression and N-glycosylation in human melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-056. doi:10.1158/1538-7445.AM2017-LB-056
Diverse <i>BRCA1</i> and <i>BRCA2</i> Reversion Mutations in Circulating Cell-Free DNA of Therapy-Resistant Breast or Ovarian Cancer
Authors: Britta Weigelt, Iñaki Comino-Méndez, Ino de Bruijn, Lei Tian, Jane L. Meisel, Isaac García-Murillas, Charlotte Fribbens, Ros Cutts, Luciano G. Martelotto, Charlotte K.Y. Ng, Raymond S. Lim, Pier Selenica, Salvatore Piscuoglio, Carol Aghajanian, Larry Norton, Rajmohan Murali, David M. Hyman, Laetitia Borsu, Maria E. Arcila, Jason Konner, Jorge S. Reis-Filho, Roger A. Greenberg, Mark E. Robson, Nicholas C. Turner
Journal: Clinical Cancer Research (2017)

Abstract Purpose: Resistance to platinum-based chemotherapy or PARP inhibition in germline BRCA1 or BRCA2 mutation carriers may occur through somatic reversion mutations or intragenic deletions that restore BRCA1 or BRCA2 function. We assessed whether BRCA1/2 reversion mutations could be identified in circulating cell-free DNA (cfDNA) of patients with ovarian or breast cancer previously treated with platinum and/or PARP inhibitors. Experimental Design: cfDNA from 24 prospectively accrued patients with germline BRCA1 or BRCA2 mutations, including 19 patients with platinum-resistant/refractory ovarian cancer and five patients with platinum and/or PARP inhibitor pretreated metastatic breast cancer, was subjected to massively parallel sequencing targeting all exons of 141 genes and all exons and introns of BRCA1 and BRCA2. Functional studies were performed to assess the impact of the putative BRCA1/2 reversion mutations on BRCA1/2 function. Results: Diverse and often polyclonal putative BRCA1 or BRCA2 reversion mutations were identified in cfDNA from four patients with ovarian cancer (21%) and from two patients with breast cancer (40%). BRCA2 reversion mutations were detected in cfDNA prior to PARP inhibitor treatment in a patient with breast cancer who did not respond to treatment and were enriched in plasma samples after PARP inhibitor therapy. Foci formation and immunoprecipitation assays suggest that a subset of the putative reversion mutations restored BRCA1/2 function. Conclusions: Putative BRCA1/2 reversion mutations can be detected by cfDNA sequencing analysis in patients with ovarian and breast cancer. Our findings warrant further investigation of cfDNA sequencing to identify putative BRCA1/2 reversion mutations and to aid the selection of patients for PARP inhibition therapy. Clin Cancer Res; 23(21); 6708–20. ©2017 AACR.
Abstract 412: Genetic variation in platinum-sensitive and platinum-resistant high-grade serous epithelial ovarian cancer
Authors: Tara Castellano, Leslie H. Clark, Naim Rashid, Victoria Bae-Jump
Journal: Cancer Research (2017)

Abstract Background: We examined the association of platinum resistance with genetic mutations in high grade serous ovarian cancer (HSOC) patients undergoing high-throughput genomic tumor sequencing. Methods: Snap-frozen and fresh frozen paraffin embedded tissue samples were collected from HSOC patients enrolled on UNCseq (NCT01457196). UNCSeq is an institutional protocol which uses next generation sequencing to detect genetic mutations in a wide array of malignancies. Illumina libraries were prepared separately from tumor and a matched normal sample from each patient. Relevant targets were enriched by a custom designed Agilent SureSelect hybrid capture enrichment library using standard protocols. Samples were sequenced on Illumina HiSeq machines in a variety of formats. Mutations with a quality score &amp;lt;100 were filtered from the data set, and only mutations rated to have a moderate to high impact were retained. Medical record review determined platinum sensitivity or platinum resistance. Tumors were defined as platinum sensitive or resistant if patients were noted to have &amp;gt; or &amp;lt; 6 months of disease free interval following completion of induction therapy, respectively. Results: Overall 39 HSOC cases met inclusion criteria; 32 tumors met criteria for platinum sensitive and 7 platinum resistant. 308 mutations were noted in at least one individual across all patients. The top observed mutations in platinum sensitive HSOC were TP53 (41%, n= 13), GucylA2 (19%, n=6), MLL2 (19%, n=6) and MTOR (16%, n=5). The top observed mutations in platinum resistant tumors were TP53 (71%, n=5), TET1 (43%, n=3), NF1 (43%, n=3) and MLL3 (43%, n=3). There was a trend toward more p53 mutations in resistant tumors (71% versus 41%, p=0.21) There was no difference in the total number of mutations per tumor in platinum sensitive and resistant patients, (3 vs. 4, p=0.516). Conclusions: We did not detect a difference in the number of genetic mutations in HSOC according to platinum sensitivity. Platinum resistant tumors had a trend toward higher frequency of TP53 mutations than platinum sensitive HSOCs. Furthermore, we identified 3 frequently mutated genes in platinum resistant HSOC: TET1, an epigenetic regulator, NF1, a tumor suppressor gene and MLL3, a histone modifier gene. Ongoing tumor sequencing of HSOCs on UNCseq will help to confirm these results. Citation Format: Tara Castellano, Leslie H. Clark, Naim Rashid, Victoria Bae-Jump. Genetic variation in platinum-sensitive and platinum-resistant high-grade serous epithelial ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 412. doi:10.1158/1538-7445.AM2017-412
Abstract 100: A Novel Anti-cell Death Mechanism by Targeting the Biosynthesis of Oligosaccharide in ER
Authors: Xiangwei Luo, Wenjuan Zhou, Lingling Wei, Liang Wei, Fengxue Zhang
Journal: Circulation Research (2015)

The pathological expression of many of the deadly human diseases such as myocardial infarction, renal failure etc. is cell death. In cancer research, myriads of ways have been found to kill a cell. However, we are still craving for an applicable mechanism to prevent cell death. The majority of the current research is to directly target the apoptosis pathway. While some compounds have been developed, none of them are pharmaceutically important likely due to the inherent toxic nature of the target. Here, we report a novel mechanism to block the cell death pathway by activating the cells’ own protective programs coded for stress. Components of the unfolded protein response (UPS) in ER have been implicated in the protection of ischemia/reperfusion heart in recent research. By targeting the biosynthesis of oligosaccharide, which activated UPS as indicated by the expression of the ER chaperones Grp94 and Grp78, we were able to completely block the Hsp90 inhibitor induced apoptotic cell death as well as the oxidative stress (as exemplified by sodium nitroprusside, SNP) induced necrotic cell death in multiple cell lines. Caspase-3 activation and PARP cleavage were nearly completely inhibited. While awaiting further exploration, the biosynthesis of the oligosaccharide could turn out to be an applicable target for acute conditions such as cardiac injury because of its relatively safe nature.