bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract A038: Establishing ubiquitylation pattern in tissues and cells efficient method to monitor cancer drug function and biomarkers
Authors: Lu Xiaolong , Singh Rajesh , Song Chengcheng , Foote Peter 
Published: August 2018

Abstract
The cell regulates its function by altering ubiquitylation status of many key proteins, especially oncoproteins. As a result, these ubiquitin proteasome system (UPS) substrates and the relevant UPS enzymes have been identified as attractive anticancer targets. However, to date, the only effective way to measure these effects has been by immunoprecipitation coupled with immunoblot analysis (IP/IB) or by mass spectrometry methods, which are either insensitive, low throughput, or highly intensive. Here, we describe two Tandem Ubiquitin Binding Entity (TUBE)-based assays, UbiQuant S and UbiTest, that provide a platform to efficiently detect ubiquitylation of anticancer targets. UbiQuant S is a high-throughput assay to quantify ubiquitylation status in a cell or tissue. Ubiquitylated proteins and the nature poly-ubiquitin are identified by energy transfer between tagged TUBE and antibody against the target protein that is poly-ubiquitylated. Interaction between TUBE and antibody is registered in a label-free manner in a solution. In case the level of ubiquitylated protein is extremely low or cannot be detected by antibody, ubiquitylated proteins can be affinity purified by TUBEs attached to agarose or magnetic beads and FRET or alphaLISA experiment is repeated. Furthermore, we have extended the technology to identify K63- and K48-linked poly-ubiquitin proteins by poly-ubiquitin chain selective TUBEs. UbiTest is an immunoblot-based assay, which can be used to verify the result of UbiQuant S. Compared to traditional ubiquitin IP/IB, this assay avoids epitope masking of antibodies caused by ubiquitin modification. Several important therapeutic targets have been used to verify these assays, including Cbl-b and USP7 immune oncology drug targets. The high efficiency and sensitivity of these assays have wide applications in drug discovery targeting ubiquitylation-dependent signaling pathways. Examples from DUBs and ubiquitin ligase inhibitors will illustrate the power of this system. These novel technologies will equip researchers with versatile tools to better understand the role of ubiquitylation in cancer treatment and monitoring biomarkers in response to drug action.
Citation Format: Xiaolong Lu, Rajesh Singh, Chengcheng Song, Peter Foote. Establishing ubiquitylation pattern in tissues and cells efficient method to monitor cancer drug function and biomarkers [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A038.
Abstract A042: Genomic predictors of chemotherapy efficacy in gastric cancer in the GC0301/TOP002 phase III trial
Authors: Das Kakoli , Taguri Masataka , Tsuburaya Akira , Tan Patrick 
Published: August 2018

Abstract
Recent gastric cancer (GC) clinical trials have aimed to establish the efficacy of combination therapy over monotherapy; however, a role for genomic biomarkers in these trials has remained largely unexplored. Here, using the NanoString expression platform, we analyzed 105 gastric tumors from a randomized phase III Japanese clinical trial (GC0301/TOP002) testing efficacy of irinotecan plus S-1 over S-1 chemotherapy. We found that previously established proliferative subtype signatures were associated with older patients (&gt;65 years) and liver metastasis, while mesenchymal subtype signatures were associated with younger patients (≤65 years) and peritoneal metastasis. Genes associated with the tumor microenvironment (CD14, DPYD), oncogenic signaling (Wnt5A, PTRF), and chemokines (CCL5, CXCL12, CCL19) were significantly associated with patient age, Lauren’s histologic classification, tumor status, measurable lesions, and metastasis. We identified Wnt5A downregulation as a candidate predictor of improved progression-free survival (PFS) (&gt;8 weeks) in fluorouracil (S-1) monotherapy-treated patients, but not in irinotecan plus S-1 (IRI-S) combined treatment. Although not achieving statistical significance, we observed a trend for mesenchymal subtype showing a treatment interaction with IRI-S for efficacy. These findings highlight promising genomic markers that could be useful predictors of chemotherapy efficacy for better prognosis and survival outcome in gastric cancer.
Citation Format: Kakoli Das, Masataka Taguri, Akira Tsuburaya, Patrick Tan. Genomic predictors of chemotherapy efficacy in gastric cancer in the GC0301/TOP002 phase III trial [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A042.
Abstract A069: Increasing replication stress by reducing nucleoside levels sensitizes melanomas and non-small cell lung cancers to CHK1 inhibitor in vitro and in vivo
Authors: Oo Zay Yar , Proctor Martina , Stevenson Alexander , Larsen Jill , Gabrielli Brian G. 
Published: August 2018

Abstract
CHK1 inhibitors are being investigated as chemosensitizing agents with agents that increase replication stress. Here we have investigated the molecular basis of sensitivity to CHK1 inhibitors as single agents in melanoma and as combinations with subclinical doses of hydroxyurea in melanoma and non-small cell lung cancer (NSCLC). We have found that sensitivity in vitro and in vivo to single agent CHK1 inhibitor is associated with defective S phase cell cycle checkpoint response to low dNTP levels. Loss of checkpoint response by overexpressing components of the checkpoint or inhibition of Wee1, convert CHK1 inhibitor insensitive cells to sensitive, and similarly depletion of CDC25A reduces CHK1 inhibitor sensitivity in sensitive lines. The increased DNA damage found with CHK1 inhibitor treatment is not sufficient to induce cell death, and cell death was triggered without entry into mitosis. We have found that about 20% of melanomas are sensitive to CHK1 inhibitor as a single agent, but we show that &gt;70% of melanomas and NSCLCs are sensitive to combination with subclinical doses of hydroxyurea. The mechanism of cell death in the combination appears identical to CHK1 inhibitor alone in inhibitor-sensitive melanomas, with cells dying without entering mitosis. In half the cell melanomas tested, the combination produced a complete loss of viability; in the other half, the viable population after treatment was incapable of further proliferation in the absence in drug. The sensitivity to the combination is independent of other known risk factors, suggesting a significant proportion of melanoma and lung cancer patients could benefit from treatment with this drug combination.
Citation Format: Zay Yar Oo, Martina Proctor, Alexander Stevenson, Jill Larsen, Brian G. Gabrielli. Increasing replication stress by reducing nucleoside levels sensitizes melanomas and non-small cell lung cancers to CHK1 inhibitor in vitro and in vivo [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A069.
Abstract A103: ATM inhibitor AZD0156 in combination with irinotecan: the use of mathematical modeling to predict efficacious doses and schedules from preclinical data
Authors: Cadogan Elaine 
Published: August 2018

Abstract
AZD0156 is a first- and only-in-class, potent, and selective ATM inhibitor. It is being investigated in clinical ascending dose studies in combination with olaparib or irinotecan. Preclinical data on the AZD0156 irinotecan combination have been used to determine which doses and schedules should be investigated to maximize efficacy. The effects of AZD0156 and irinotecan in combination on the distribution of cell cycle phases have been investigated in vitro by flow cytometry. Cell population growth and DNA damage response biomarkers such as pATM foci, gH2AX foci, and micronuclei were described in detail using high-throughput immunofluorescence imaging. In vivo, preclinical xenograft studies have been carried out to examine the effects on pharmacodynamics and tumor growth from different doses and schedules of both agents. These in vitro and in vivo data have been integrated into a mechanistic mathematical model that supports the combination hypothesis, and allows prediction of pharmacodynamic and tumor volume responses under different doses and schedules. In particular, the effects of clinical doses and schedules can be predicted by taking into account differences between mouse and human pharmacokinetics for the co-agents. It can be challenging to identify the optimum schedule during clinical ascending dose studies, especially in combination cases with multiple variables, such as the doses of each agent, time gaps between doses, and times without dosing between cycles. Preclinical information, together with mathematical modeling, can be used to guide the prioritization of clinical experiments.
Citation Format: Elaine Cadogan. ATM inhibitor AZD0156 in combination with irinotecan: the use of mathematical modeling to predict efficacious doses and schedules from preclinical data [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A103.
Abstract A105: Checkpoint kinase 1 and 14-3-3 proteins inhibit atypical E2Fs to prevent a permanent cell cycle arrest
Authors: Yuan Ruixue 
Published: August 2018

Abstract
The atypical E2Fs, E2F7 and E2F8, act as potent transcriptional repressors of DNA replication genes, providing them with the ability to induce a permanent S-phase arrest and suppress tumorigenesis. Surprisingly in human cancer, transcript levels of atypical E2Fs are frequently elevated in proliferating cancer cells, suggesting that the tumor suppressor functions of atypical E2Fs might be inhibited through unknown post-translational mechanisms. Here, we show that E2F7 and E2F8 can be directly phosphorylated by Checkpoint kinase 1 (Chk1) to prevent a permanent cell cycle arrest. We found that multiple 14-3-3 protein isoforms interact with both E2Fs in a Chk1-dependent manner. We show that 14-3-3 proteins inhibit E2F7 and E2F8 repressor function without disrupting their binding to target gene promoters or subcellular translocation. In addition, we observed that high levels of 14-3-3 strongly correlate with upregulated transcription of atypical E2Fs target genes in human cancer. Thus, we reveal that Chk1 and 14-3-3 proteins cooperate to inactivate the transcriptional repressor functions of atypical E2Fs. This mechanism might be of particular importance to cancer cells, since they are exposed frequently to replication stress and DNA-damaging therapeutic reagents, which are both known inducers of Chk1 activity.
Citation Format: Ruixue Yuan. Checkpoint kinase 1 and 14-3-3 proteins inhibit atypical E2Fs to prevent a permanent cell cycle arrest [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A105.
Abstract A107: Development of polymerase theta inhibitors for precision medicine in BRCA-deficient cancers
Authors: Pomerantz Richard T. 
Published: August 2018

Abstract
DNA polymerase theta (Polq) is important for the proliferation of BRCA-deficient cancer cells, but is dispensable for normal cell growth. Thus, Polq is widely considered to be an important new drug target for BRCA-deficient cancers, such as those in the breast, ovary, prostate, pancreas, and blood. We have identified "expanded-size" nucleoside analogs that are uniquely incorporated by Polq and inhibit its activity. We have also identified small-molecule inhibitors of Polq through a random high-throughput screening approach. Consistent with the ability of Polq to promote the survival of BRCA-deficient cells, preliminary studies show that a newly identified Polq small-molecule inhibitor selectively kills cells deficient in BRCA2, while sparing wild-type cells. We are currently further advancing Polq nucleoside analog and small-molecule inhibitors via structure activity relationship (SAR) and medicinal chemistry studies with the goal of testing these inhibitors in BRCA-deficient PDX mouse models.
Citation Format: Richard T. Pomerantz. Development of polymerase theta inhibitors for precision medicine in BRCA-deficient cancers [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A107.
Abstract A114: SIRT2 directs DNA-PKcs in the DNA damage response
Authors: Head Pamelasara E. , Zhang Hui , Yu David S. 
Published: August 2018

Abstract
DNA Damage Response (DDR) pathways, including DNA repair and cell-cycle checkpoints, are critical for maintaining genome integrity and preventing disease including cancer. Deficiencies in the DDR result in increased susceptibility to cancer, a leading cause of morbidity and mortality worldwide. However, the mechanisms mediating the activities of the DDR and how their dysregulation leads to genomic instability and a tumor-permissive phenotype are not fully understood. Sirtuin 2 (SIRT2) is a class III NAD+ dependent histone deacetylase implicated in maintaining genomic stability and tumor suppression in that genetic loss of Sirt2 results in both genomic instability and specific murine breast and liver tumors. SIRT2 deficiency in human cells results in hypersensitivity to DNA damage, impaired recovery from replication arrest, and a defect in the G2/M checkpoint in response to ionizing radiation (IR). Preliminary data demonstrate a strong interaction between SIRT2 and DNA-PKcs following IR in human cell lines. DNA-PKcs is a well-established nonhomologous end-joining (NHEJ) mediator kinase that is capable of self-regulation by autophosphorylation at serine 2056 to promote end ligation. SIRT2 knockdown inhibits localization of DNA-PKcs to sites of microirradiation and co-immunoprecipitation with the KU complex in response to IR. Inhibition of localization leads to decreased self-activation of DNA-PKcs at serine 2056 and decreased interaction with KU in SIRT2 knockout lines in response to IR. DNA-PKcs self-phosphorylation and interaction with KU is rescued following damage with wild-type SIRT2 but not with deacetylase dead SIRT2 H187Y, indicating that SIRT2 enzymatic function is necessary for regulation. Overexpression of SIRT2 leads to premature autophosphorylation of DNA-PKcs a serine 2056 without induction of DNA damage. We also demonstrate SIRT2 is capable of deacetylating DNA-PKcs in vitro and in cells. SIRT2 overexpression leads to increased DNA-PKcs self-phosphorylation before and after IR. In addition SIRT2 knockout cell lines exhibit increased sensitivity to IR and CPT. Overall, these data demonstrate that SIRT2 could be a strong potential cancer therapeutic target.
Citation Format: Pamelasara E. Head, Hui Zhang, David S. Yu. SIRT2 directs DNA-PKcs in the DNA damage response [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A114.
Abstract A115: Targeting glycolysis and RAD51-dependent repair in B-lymphoid cancers
Authors: Hasham Muneer G. , Chow Kin-hoe , Wilson John , LaBrie Nathan , Perkins Bryant , Branca Jane , Sproule Thomas , Roopenian Derry 
Published: August 2018

Abstract
Activation-Induced Cytidine Deaminase (AID) mutates and modifies the IgH locus. However, it also initiates double-strand breaks (DSBs) throughout the genome. This effect of AID is balanced by RAD51-dependent homologous recombination repair. Importantly, we previously showed that inhibition of RAD51 function by a small-molecule inhibitor leads to cell death of AID-positive neoplastic cells. While we have used AID-RAD51 imbalance as a potential chemotherapy approach, the efficacy of current RAD51 inhibitors can be further improved. Studies have shown a relationship between glycolysis and RAD51 function, and therefore targeting the glycolytic pathway is a viable strategy to enhance RAD51 inhibitor efficacy. Here we show that glycolytic inhibitor 2DG and RAD51 inhibitor DIDS act synergistically to reduce B-lymphocyte human chronic lymphocytic leukemia proliferation ex vivo, and mice xenografted with this cell line showed significant reduction in the tumor burden in the presence of both 2DG and DIDS. These data suggest that the glycolytic pathway and DNA repair can be simultaneously targeted to produce better chemotherapies against B-lymphoid cancers.
Citation Format: Muneer G. Hasham, Kin-hoe Chow, John Wilson, Nathan LaBrie, Bryant Perkins, Jane Branca, Thomas Sproule, Derry Roopenian. Targeting glycolysis and RAD51-dependent repair in B-lymphoid cancers [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A115.
Abstract A171: Epigenetic modification of α-N-acetylgalactosaminidase (NAGA) enhances cisplatin resistance in ovarian cancer
Authors: Ju Woong , Sung Hye Youn , Ahn Jung-Hyuck 
Published: August 2018

Abstract
Although cisplatin is one of the most effective antitumor drugs for ovarian cancer, the emergence of chemoresistance to cisplatin in over 80% of initially responsive patients is a major barrier to successful therapy. The precise mechanisms underlying the development of cisplatin resistance are not fully understood, but alteration of DNA methylation associated with aberrant gene silencing may play a role. To identify epigenetically regulated genes directly associated with ovarian cancer cisplatin resistance, we compared the expression and methylation profiles of cisplatin-sensitive and -resistant human ovarian cancer cell lines. We identified α-N-acetylgalactosaminidase (NAGA) as one of the key candidate genes for cisplatin drug response. Interestingly, in cisplatin-resistant cell lines, NAGA was significantly downregulated and hypermethylated at a promoter CpG site at position +251 relative to the transcriptional start site. Low NAGA expression in cisplatin-resistant cell lines was restored by treatment with a DNA demethylation agent, indicating transcriptional silencing by hyper-DNA methylation. Furthermore, overexpression of NAGA in cisplatin-resistant lines induced cytotoxicity in response to cisplatin, whereas depletion of NAGA expression increased cisplatin chemoresistance, suggesting an essential role of NAGA in sensitizing ovarian cells to cisplatin. These findings indicate that NAGA acts as a cisplatin sensitizer and its gene silencing by hypermethylation confers resistance to cisplatin in ovarian cancer. Therefore, we suggest NAGA may be a promising potential therapeutic target for improvement of sensitivity to cisplatin in ovarian cancer.
Citation Format: Woong Ju, Hye Youn Sung, Jung-Hyuck Ahn. Epigenetic modification of α-N-acetylgalactosaminidase (NAGA) enhances cisplatin resistance in ovarian cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A171.
Abstract A173: Long-term responders to epigenetic modulators: abexinostat and pazopanib
Authors: Aggarwal Rahul , Pawlowsk Nela , Grabowsky Jennifer , Harb Armand , Abri-Lavasani Kamran , Thomas Scott , Munster Pamela N. 
Published: August 2018

Abstract
Characterization of long-term responders in a phase I trial evaluating the role of epigenetic modulation of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor by using a histone deacetylase abexinostat in combination with pazopanib to enhance response and reverse resistance. Patients and Methods: Pazopanib was administered once a day on days 1 to 28 and abexinostat was administered orally twice a day on days 1 to 5, 8 to 12, and 15 to 19 (schedule A) or on days 1 to 4, 8 to 11, and 15 to 18 (schedule B). Dose escalation (3 + 3 design) in all solid tumors was followed by dose expansion in renal cell carcinoma (RCC). Histone acetylation and HDAC2 expression were correlated long-term responders, &gt;1y). Results: Fifty-one patients including RCC (N = 22) were enrolled, including 30 (59%) with one or more lines of prior VEGF-targeting therapy. Toxicities and PK studies were reported previously. 7 pts had response &gt; 23 months (23-60+), including 5/22 patients with RCC, and one patient with medullary thyroid and thymic neurondocrine cancer. Long-term response was associated with high HDAC2 expression in PBMCs, increased histone acetylation, and modulation of VEGF level. Conclusion: Epigenetic modulation with HDAC inhibitors is strongly dependent on host factors to promote long-term benefit to abexinostat and pazopanib in pretreated patients.
Citation Format: Rahul Aggarwal, Nela Pawlowsk, Jennifer Grabowsky, Armand Harb, Kamran Abri-Lavasani, Scott Thomas, Pamela N. Munster. Long-term responders to epigenetic modulators: abexinostat and pazopanib [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A173.