bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract A50: Epstein-Barr virus in the putative stem cell fraction of some multiple myeloma cell lines.
Authors: Biswas Sunetra , Shamay Meir , Shirley Courtney M. , Yonescu Raluca , Matsui William H. , Borrello Ivan , Jones Richard J. , Ambinder Richard F. 
Published: August 2014

Abstract
Epstein-Barr virus (EBV) associated cancers have traditionally been thought to harbor the viral genomes as nuclear plasmids in all or nearly all of a patient's tumor cells as determined by in situ hybridization (ISH). We discovered EBV in 4 out of 7 standard multiple myeloma (MM) cell lines. In these positive cell lines, EBV was found in only a subpopulation of cells. For example, in MM.1S (a MM cell line) less than 1% of the cells harbored viral DNA as determined by limiting dilution PCR. These rare infected cells carried approximately 20 EBV copies. Fluorescence in situ hybridization (FISH) confirmed the presence of multiple copies of the EBV genome in rare cells. Immunofluorescence similarly detected the presence of viral genomes expressing EBV nuclear antigen (EBNA) - 1 and 2 in rare cells. Reverse transcriptase PCR confirmed EBNA1 and EBNA2 viral RNA expression. The cells that harbor virus are phenotypically distinct CD19+CD138− B cells. The phenotype overlaps with that identified as a MM cancer stem cell population. Viral genomes were not detected in the plasma cell-like population (CD19−CD138+). The results are consistent with the possibility that EBV is present in MM cancer stem cells in some MM cell lines and that virus is lost as these MM cancer stem cells with a B cell-like phenotype differentiate into plasma cells. Introduction of a dominant negative shRNA of the EBV EBNA-1, a protein essential for viral replication, decreased the proliferation of only the MM cell lines which were positive for EBV. Insertion of the dominant negative EBNA-1 shRNA had no effect on EBV negative MM cell lines, suggesting that EBV plays a role in the growth kinetics of cell lines even when present in a tiny percentage of cells. These results suggest that in some MM lines, EBV is harbored in a B cell-like progenitor population that overlaps with the putative cancer stem cell fraction. The loss of EBV inhibits cell proliferation and that EBV is lost during the B-cell to plasma cell differentiation process. The results presented here suggest that identifying the EBV status of MM patients prior to treatment might lead to a more efficient course of therapy.
Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A50.
Citation Format: Sunetra Biswas, Meir Shamay, Courtney M. Shirley, Raluca Yonescu, William H. Matsui, Ivan Borrello, Richard J. Jones, Richard F. Ambinder. Epstein-Barr virus in the putative stem cell fraction of some multiple myeloma cell lines. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A50.
Abstract A90: Feedback activation of EGFR drives resistance to BRAF(V600E) inhibition in breast cancer.
Authors: Yang Yj , Na HJ , Kim Ws , Bong JP , Beak SJ , Kim Jw , Park Jk , Hong Hj , Shin Dy , Kwon Jh , Lee Ej , Koh Yw , Choi Ec 
Published: August 2014

Abstract
Purpose: The BRAFV600E mutation has shown significant activity in the several tumor types, including breast, melanoma, and colorectal cancer. The selective inhibitor of BRAFV600, PLX4032 (vemurafenib), has shown clinical response in patients with BRAFV600Emelanoma, especially but not in 20-40% of patients despite the presence of a BRAFV600E. Thus, it is important to understand the molecular mechanisms of resistance to improve outcomes in patient with BRAF mutation. We aimed to investigate the cause of the limited therapeutic effect of PLX4032 in cancers harboring the mutant BRAFV600E gene.
Experiment Design: We investigated the correlation between RTK pathway activation and sensitivity to PLX4032 in several types of cancer cell lines harboring the BRAFV600E. Cell lines were exposed to PLX4032 and pharmacologic inhibitors and in combination with each other to inhibit RTK signaling. Cell survival and apoptosis were measured using MTT assay, Annexin V/PI staining, and colony forming assay. Real-time PCR, Western blots were performed to determine possible mechanisms of resistance and predictors of synergy.Results: In a comparison with BRAFV600E cancer cells, we show that PLX4032-resistant MDA-MB breast cancer cells have the enhanced level of p-EGFR in the presence of PLX4032. PLX4032 treatment causes a rapid feedback activation of EGFR and up-regulation of AKT in MDA-MB cells, which supports continued proliferation in the presence of BRAFV600E inhibition. We show that EGFR activation acquired resistance to BRAF inhibition using EGFR inhibitor. Gefitinib, EGFR inhibitor, shows strong synergy with a BRAFV600E inhibitor in short-time and long-time treatment. In addition, we investigated that rapid feedback activation of EGFR regulates the expression of epithelial to mesenchymal transition (EMT) regulators by
Real-time PCR, which resulted in high migratory potentials in invasion assay and wound healing assay. These results provide rational therapeutic strategies for clinical studies in this poor prognosis subtype of BRAFV600E inhibitor.
Conclusions: Our data suggest that BRAFV600E mutant breast cancers, for which there are currently no targeted treatment options available, might benefit from combination therapy consisting of BRAF and EGFR inhibitors.
Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A90.
Citation Format: Yj Yang, HJ Na, Ws Kim, JP Bong, SJ Beak, Jw Kim, Jk Park, Hj Hong, Dy Shin, Jh Kwon, Ej Lee, Yw Koh, Ec Choi. Feedback activation of EGFR drives resistance to BRAF(V600E) inhibition in breast cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A90.
Abstract B109: The role of SIRT6 in drug resistance and cellular senescence in cancer.
Authors: Khongkow Mattaka , Lam Eric 
Published: August 2014

Abstract
Introduction: The Sirtuin family consists of 7 members. They comprize highly conserved NAD+-dependent deacetylases that play an important role in a board spectrum of cellular processes, including metabolism, differentiation, survival and cellular senescence. It has also been suggested that these proteins are central to cancer development and drug resistance. Recent studies have documented that SIRT6, a nuclear chromatin-associated protein, has a key role in genomic stability and degenerative pathologies associated with ageing. Moreover, SIRT6 has been reported to have a function in the regulation of DNA damage repair. Therefore, this research aims to investigate the role of SIRT6 in drug resistance and cellular senescence in cancer cells.
Methods: Cell lines that we have used in this research consist of sensitive and resistant breast cancer cells, Hela cells and mouse embryonic fibroblasts (MEFs). To investigate the role of SIRT6 in drug resistance, we treated cells with either epirubicin or paclitaxel, then performed immunofluorescent, comet and repair assays to investigate DNA damage repair. Clonogenic and beta-galactosidase assays were also used to investigate long-term survival and cellular senescence.
Results: We found that SIRT6 is elevated in drug resistant cells compared to drug sensitive parental cells and that SIRT6 mediates drug resistance by increasing DNA damage repair. Sirt6-/- MEFs have lower levels of γH2AX accumulation compared to WT MEFs. These higher levels of SIRT6 are also associated with the lower activities of p53 and FOXO3a which are two important cell cycle/survival regulators. Here, we show that depletion of SIRT6 in cancer cells results in a decrease in long-term survival and lower HR and NHEJ DNA repair activity. SIRT6-deficeint cells also exhibit the induction of senescence-associated β-galactosidase activity and flat cell morphology.
Conclusion: Our results suggest a novel role of SIRT6 in epirubicin and paclitaxel treatment resistance and cellular senescence. SIRT6 could be a potential biomarker for identifying tumors that are likely to be resistant to these chemotherapeutic agents. It might be also a useful therapeutic target for the prevention of acquired drug resistance and for improving the efficiency of drug treatment.
Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B109.
Citation Format: Mattaka Khongkow, Eric Lam. The role of SIRT6 in drug resistance and cellular senescence in cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B109.
Abstract B11: In vivo ADCC-mediated antitumor activity study with new preclinical humanized models.
Authors: Mignard Caroline , Duchamp Olivier , Mirjolet Jean-François , Ohnishi Yasuyuki , KATANO Ikumi , ITO Mamoru 
Published: August 2014

Abstract
Experimental systems to effectively evaluate therapeutic antibodies are urgently needed. One of the mechanisms used by antibodies to kill tumor cells is antibody-dependent cellular cytotoxicity (ADCC) in which natural killer cells (NK) are the main mediator.
The generation of humanized mice as immunodeficient mice (such as NOG) engrafted with hematopoietic stem cells (HSC) demonstrated their usefulness for studying the human immune system. Nevertheless, one issue of this humanized model is the incomplete maturation of NK cells.
To circumvent this lack of functionality the Central Institute for Experimental Animals (CIEA) has developed the second generation of transgenic NOG mice expressing human IL2 or IL15 (NK-NOG). hIL-2 and hIL-15 NOG mice were generated by microinjection of DNA fragments containing human IL-2 cDNA or human IL-15 cDNA replaced with a hIL-2 signal peptide, under the control of a CMV-promoter, into fertilized eggs of NOD-IL-2Rgnull mice. The serum levels of hIL-2 and hIL-15 in mice were 1-2 and 0.1-0.2 ng/mL, respectively.
Humanization of NK-NOG mice was validated using freshly collected or frozen hematopoietic stem cells (HSCs) in transgenic NK-NOG mice. The characterization of the reconstituted NK-NOG mice was done in peripheral blood as well as central lymphoid organs such as bone marrow and spleen using flow cytometry. Moreover, the human NK cell function was evidenced using an ex vivo 51Cr assay demonstrating lysis properties of NK cells from collected spleen.
Finally in vivo NK-mediated ADCC was evaluated in IL2-NOG mice simultaneously engrafted with human immune system and human Burkitt's lymphoma. Reconstituted mice were treated with Rituximab to examine immune system-related antitumor activity.
Genetic manipulation of the host continue to improve the ability of humanized mice to more accurately recapitulate the in vivo function of human immune cells such as NK cells.
Prediction of ADCC-mediated antitumor activity of humanized antibodies is now routinely feasible for preclinical evaluation.
Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B11.
Citation Format: Caroline Mignard, Olivier Duchamp, Jean-François Mirjolet, Yasuyuki Ohnishi, Ikumi KATANO, Mamoru ITO. In vivo ADCC-mediated antitumor activity study with new preclinical humanized models. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B11.
Abstract B135: Secretion of R-spondin1 is regulated by C-mannosylation.
Authors: Niwa Yuki , Simizu Siro 
Published: August 2014

Abstract
Background and Objective: R-spondin (Rspo) family proteins (Rspo1-4) activate canonical Wnt/β-catenin signaling and noncanonical Wnt/PCP signalling, and are related to differentiation, tissue development, and sex determination. It is reported that Rspos bound to Wnt receptor (Frizzled8), Wnt co-receptor (LRP6), and LGR4-6, but the mechanism which Rspos activate Wnt signaling remains unclear.
Rspo1, a Wnt signal agonist, contains one thrombospondin type-1 repeats (TSR-1) domain. TSR-1 domain frequently involves Trp-Xaa-Xaa-Trp/Cys motif (Xaa represents any amino acids), which is the consensus sequence of protein C-mannosylation. Although several TSR-1 containing proteins have been reported to be C-mannosylated, it is not reported whether Rspo1 is C-mannosylated or not. In this study, we investigated whether Rspo1 is C-mannosylated, and the role of C-mannosylation on Rspo1 functions.
Results: We established Rspo1-overexpressing HT1080 cells, and purified recombinant Rspo1 protein from conditioned medium of the cells. Using mass spectrometric analyses, we revealed that Rspo1 is C-mannosylated at both Trp153 and Trp156. Replacement of mannosylated Trp to Ala residues inhibited secretion of Rspo1, indicating that C-mannosylation of Rspo1 is involved in the secretion. It is reported that Rspo1 synergistically activates canonical Wnt/β-catenin signaling in the presence of Wnt3a. In C-mannosylated tryptophan residues-defective Rspo1-expressing cells, Wnt3a did not activate promoter activity of TCF. Therefore, it is suggested that C-mannosylation of Rspo1 might be a new target of cancer treatment.
Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B135.
Citation Format: Yuki Niwa, Siro Simizu. Secretion of R-spondin1 is regulated by C-mannosylation. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B135.
Abstract B136: Study of the response of melanoma lines to BRAF/MEK inhibitors and combination drug treatments.
Authors: Dastur Anahita , Benes Cyril 
Published: August 2014

Abstract
The serine-threonine protein kinase, BRAF, is a frequently mutated oncogene, found in cancers of the skin, thyroid and large intestine. It is especially prevalent in malignant melanoma, where it occurs in 40-60% of the cases. The most common BRAF mutation is the valine to glutamate substitution at position 600 of the kinase (V600E). This substitution, seen in ninety percent of the BRAF cases, leads to constitutive activation of the kinase, and the downstream MEK-ERK pathway. Appropriately, several drugs have been designed to inhibit BRAF, with a broad range of outcomes in clinical trials. Unfortunately, all patients, including those showing complete responses, eventually develop resistance to single agent therapy. Our goal is to come up with effective drug combinations that would delay, or even prevent, the cancer from becoming resistant to treatment.
We used a panel of 43 melanoma lines, comprising of 28 BRAF mutants, 12 NRAS mutants and 3 lines that were wild type for these two genes. Besides BRAF and NRAS, we have the mutational status of 65 other commonly mutated cancer genes for all the lines. We assembled a set of 25 drugs targeting a wide range of proteins, including PI3K/mTOR inhibitors, the apoptosis machinery, as well as some epigenetic modulators. The melanoma lines were treated with these drugs, either (i) alone or (ii) in combination with the B-RAF inhibitor vemurafenib or (iii) in combination with the MEK inhibitor Selumetinib, for 72 hrs over a nine point, 256-fold concentration range. Viability and apoptosis were measured using cell titer glo (Promega).
The results from this pilot study are discussed here.
Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B136.
Citation Format: Anahita Dastur, Cyril Benes. Study of the response of melanoma lines to BRAF/MEK inhibitors and combination drug treatments. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B136.
Abstract B145: Use of μCT imaging in the PyMT breast cancer model to monitor lung metastasis development and determine therapeutic benefit in real time.
Authors: Meade Mary Anne , Balagurunathan Deepa , Bull Chris , Lister Deanne , Trachet Erin , Smith Bryan , Flynn Daniel , Wise Scott C. 
Published: August 2014

Abstract
Breast cancer is the most frequently diagnosed form of cancer and the second leading cause of death in women. Death and most of the complications associated with breast cancer are due to the metastasis of the primary tumor to the lung, as well as other tissues. To visualize the metastatic process in real time, the genetically engineered mouse mammary tumor virus-polyoma middle T (MMTV-PyMT) mouse model was employed along with in vivo µCT (computed tomography) imaging to evaluate and characterize the size and incidence of lung nodules. µCT images are able to detect lung nodules as small as approximately 0.5mm3. The MMTV-PyMT model is widely used to evaluate metastatic breast cancer; the model produces lung metastases (80-90% incidence rate) in a more clinically relevant manner in a syngeneic mouse with intact immune system. In this study female MMTV-PyMT mice were allowed to develop primary mammary fat pad tumors (&gt;3grams) which were then excised and processed into single cell suspension. Syngeneic female mice (FVB/J) were implanted with the cell suspension into mammary fat pad #4 and the resulting tumors were resected once the primary tumor burden surpassed 750mg (late stage). Standard twice weekly intravenous therapy with eribulin at 1mg/kg was initiated following resection and continued the duration of the experiment. µCT images were used to assess the presence and size of lung metastases in vivo starting at 3 weeks post-primary tumor resection. Mice were monitored daily via cage side observations and imaged a second time once labored breathing was apparent. Treatment with eribulin (1mg/kg, IV) not only decreased the incidence of lung metastases by 75% compared to the vehicle control group but also inhibited the ability of the primary tumor to regrow. Coupling the MMTV-PyMT model with µCT imaging allowed for the longitudinal evaluation of therapeutic efficacy on progressive lung metastases. Visualizing lung metastases in real time with in vivo imaging is advantageous since traditional pharmacology endpoints of the MMTV-PyMT model can be extremely long (20-40 weeks).
Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B145.
Citation Format: Mary Anne Meade, Deepa Balagurunathan, Chris Bull, Deanne Lister, Erin Trachet, Bryan Smith, Daniel Flynn, Scott C. Wise. Use of μCT imaging in the PyMT breast cancer model to monitor lung metastasis development and determine therapeutic benefit in real time. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B145.
Abstract B152: MR-based assessment and quantification of cerebral edema in an orthotopic mouse glioma model.
Authors: Lister Deanne R. , Balagurunathan Deepa , Baugher Meridith , Trachet Erin , McConville Patrick , Wise Scott , Leopold W.R. 
Published: August 2014

Abstract
Introduction: Brain edema is a prominent feature of brain cancer and contributes to neurologic dysfunction and impaired quality of life. While corticosteroids are the standard of care, improved treatments that are more efficacious and reduce side effects are sought after. In discovery of novel therapies for edema, animal brain tumor models that show relevant, reproducible and high incidence of tumor and cerebral edema are needed. Additionally, quantitative, non-invasive methods for detecting and measuring brain tumor associated edema are needed to facilitate therapeutic discovery efforts. In this work, an intracranial U251-luc human glioma model was characterized for edema incidence and progression. MRI-based relaxivity and contrast-enhancement protocols for edema detection and delineation from tumor tissue, were tested and characterized in the model.
Methods: Female nude mice were implanted intracranially with 1×10∧6 U251-luc (Luc-mCherry) glioma cells. Tumor volume assessment was performed by manual segmentation of T1-weighted, gadolinium-enhanced anatomical brain images based on the assumption of tumor enhancement due to leaky vessels or compromised blood-brain barrier. Edema assessment was performed by manual segmentation of T2-weighted anatomical brain images based on the assumption that enhancing regions include tumor tissue in addition to regions of brain edema. The difference in T2-weighted and T1-weighted volumes was assumed to be edema. T2 maps were also generated over the whole brain to measure T2 values over the respective regions of interest, and confirm the differentiation between tumor tissue and edema.
Results: Edema volume was successfully distinguished from contrast enhancing tumor tissue and quantified in orthotopically implanted U251-luc (Luc-mCherry) glioma. Incidence was 100%. Edema progression occurred with increasing tumor volume over time. Regions of edema exhibited greater T2 values compared to tumor tissue regions (that also had greater T2 than normal tissue). This is consistent with edematous tissue water content, compared with tumor tissue and normal brain. These results support the use of intracranial U251-luc (Luc-mCherry) as a reliable model for studying the effects of therapies targeting tumor-related cerebral edema, and the application of MR imaging for quantifying those effects real-time in vivo.
Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B152.
Citation Format: Deanne R. Lister, Deepa Balagurunathan, Meridith Baugher, Erin Trachet, Patrick McConville, Scott Wise, W.R. Leopold. MR-based assessment and quantification of cerebral edema in an orthotopic mouse glioma model. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B152.