bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3008: Effects of HSPG on inhibition of chemokine-induced angiogenesis
Authors: Ju Donghong , Speyer Cecelia , Gorski David , Kosir Mary A.
Published: May 2015

PURPOSE: The purpose of the study is to inhibit angiogenesis by using using specific inhibitors to the CXCR2 receptor that binds angiogenic CXC chemokines, while varying the concentration of heparan sulfate proteoglycan (HSPG), an important molecule for multiple angiogenesis factors.

METHODS: Using endothelial tubule formation assays on Matrigel, human umbilical vascular endothelial cells were treated with either antibody to CXCR2 or a small selective non-peptide inhibitor SB225002 (N-(2-hydroxy-4-nitrophenyl)-N9-(2-bromophenyl)urea at varying concentrations and compared to control creating a dose-response curve. Experiments were repeated using Growth Factor Reduced (GFR) Matrigel which has 40-50% less HSPG. After 4 hours incubation, endothelial tubule formation was quantified by counting tubule numbers in four random microscopic fields using the microscope camera software NIS-Elements AR 3.10 in triplicate and compared to control.

RESULTS: There was a significant and dose-dependent inhibition of endothelial tubule formation on Matrigel by SB225002 at concentrations ranging from 0.56 µM to 11 µM (p=0.04 to 0.004). The IC50 was 5.2 µM. There was also significant inhibition of tubule formation with anti-CXCR2 antibody at 20-40 µg/ml in a dose-dependent manner (p=0.001 and 0.00003), with IC50 of 33.6 µg/ml on Matrigel. However, on GFR Matrigel, the IC50 for SB225002 inhibition of endothelial tubule formation was lower at 0.61 µM with a significant dose-dependent inhibition from 0.56 µM to 11 µM (p=0.0004 to 0.00001). Anti-CXCR2 antibody inhibition of tubule formation was also significant on GFR Matrigel at 20 µg/ml (p=0.006) with IC50 of 18.6 µg/ml.

CONCLUSION: A selective non-peptide inhibitor of CXCR2 (SB225002) inhibited endothelial tubule formation with 8.5 times a lower dose when HSPG concentrations were reduced using GFR Matrigel. Angiogenesis factors such as VEGFA, FGF-2 and CXC chemokines require HSPGs on the cell surface of endothelial cells, so optimal control of angiogenesis may require control of HSPGs as well. The inhibition of transmembrane CXCR2 is important for emerging therapies for inflammation and malignancy, and associated angiogenesis.

Citation Format: Donghong Ju, Cecelia Speyer, David Gorski, Mary A. Kosir. Effects of HSPG on inhibition of chemokine-induced angiogenesis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3008. doi:10.1158/1538-7445.AM2014-3008
Abstract 3012: Converging effectors of airway lineage specification and metastasis in lung cancer
Authors: Nguyen Don X.
Published: May 2015

Lung adenocarcinoma (LUAD) is a deadly and heterogeneous subtype of non-small cell lung cancer. During LUAD progression, the emergence of alternate cell lineage traits in primary tumors correlates with poor outcome. The underlying mechanisms and biological consequences of these phenomena are poorly understood.

Using an integrated approach, we examined the molecular relationship between cell differentiation states, lung cancer subtypes, and clinical outcome, to discover a role for lineage-restricted genes in the pathogenesis of LUAD (1). Specifically, we identified two airway selective lineage transcription factors, GATA6 and HOPX, as inhibitors of metastatic progression. Down-regulation of their expression in a subset of human tumors correlates with aberrant tumor differentiation and relapses. GATA6 and HOPX cooperatively restrict the metastatic potential of LUAD cells, by modulating converging transcriptional programs of airway epithelial differentiation and malignant invasion.

Our findings demonstrate that perturbation of intrinsic cell lineage pathways is a determinant of metastasis in specific lung cancers. The implications of these findings for the origin(s) and treatment of LUAD metastasis will be discussed.

(1) Cancer Cell, 23 (6): 725-738. 2013.

Citation Format: Don X. Nguyen. Converging effectors of airway lineage specification and metastasis in lung cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3012. doi:10.1158/1538-7445.AM2014-3012
Abstract 3058: Bone marrow hematopoietic stem cell niche activation and mobilization fosters the metastatic niche
Authors: Giles Amber J. , Murgai Meera , Vicioso Yorleny , Highfil Steven , Mackall Crystal , Wexler Leonard , Lyden David , Kaplan Rosandra Natasha
Published: May 2015

Metastasis remains the main cause of mortality for patients with cancer. The process whereby a localized tumor becomes metastatic remains poorly understood. Metastasis was previously thought to be a late-stage, unidirectional migration of cells from the primary tumor to a distant site, due to acquired genetic mutations that conferred necessary metastatic attributes to the cell. However, current research demonstrates that dissemination is not a late phenomenon and although loss of metastasis suppressor genes or gain of acquired mutations can contribute to the metastatic phenotype, the cross-talk between the tumor and its microenvironment has proven to be a major driver of this process. We have found that recruited bone marrow-derived cells and changes in resident stromal cells form a microenvironment that is conducive to metastatic progression, termed the pre-metastatic niche. The recruited and resident cells that form this microenvironment are active areas of investigation. Because the bone marrow is the source for most of the recruited cell types in these distant tissue sites, we postulated that activation of the bone marrow's hematopoietic compartment plays a key role in metastatic progression. We sought to profile the changes that occur within the hematopoietic stem cell niche of the bone marrow and subsequent changes in hematopoiesis in the setting of tumor development. Within the bone marrow of tumor bearing mice we found increased proliferation of hematopoietic stem and progenitor cells. These cells are also increased in the circulation of both tumor bearing mice and patients with malignancy. Furthermore, we have determined that elevated levels of circulating hematopoietic progenitor cells can be predictive of metastatic risk, as those patients with the highest levels at diagnosis developed metastases. This biomarker may be useful in stratifying therapy for patients with localized disease who have the highest metastatic risk. Better understanding of the steps and individual factors required to establish a metastatic microenvironment can lead to novel adjuvant therapies to target this process.

Citation Format: Amber J. Giles, Meera Murgai, Yorleny Vicioso, Steven Highfil, Crystal Mackall, Leonard Wexler, David Lyden, Rosandra Natasha Kaplan. Bone marrow hematopoietic stem cell niche activation and mobilization fosters the metastatic niche. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3058. doi:10.1158/1538-7445.AM2014-3058
Abstract 3069: Radial flow microfluidic device for high-throughput affinity-based isolation of circulating tumor cells
Authors: Murlidhar Vasudha , Reddy Rishindra M. , Zeinali Mina , Grabauskiene Svetlana , Ghannad-Rezaie Mostafa , Wicha Max S. , Simeone Diane M. , Ramnath Nithya , Nagrath Sunitha
Published: May 2015

Circulating tumor cells (CTCs) are believed to play an important role in metastasis, a process accounting for the majority of cancer-related deaths. They offer a non-invasive biopsy technique to study tumors and are shown to be useful prognostic indicators. Because of their rarity in the bloodstream, microfluidic isolation techniques are complex and time-consuming, and provide yields of CTCs insufficient or non-viable for studies other than enumeration. Additionally, due to the low processing speeds, the volumes of blood processed remain limited and can be a hindrance to obtaining higher yields of CTCs and their potential use as biomarkers of early diagnosis. Here we report a novel high throughput microfluidic technology, the OncoBean Chip, employing radial flow that introduces a varying shear profile across the device and enables efficient cell capture by affinity at high flow rates. The cell recovery from whole blood was validated with cancer cell lines H1650 and MCF7, and the OncoBean Chip achieved an efficiency >80% at a throughput of 10 mL/hr, a flow rate yet achieved only in physical size based separation techniques. A cell viability of 92.91% shows that the cells recovered at high throughput could still be used for downstream analysis. Clinical competence was demonstrated in blood specimens from breast, pancreatic and lung cancer patients. The OncoBean Chip thus holds potential applications in the diagnosis of early stage cancers, where the low numbers of CTCs could be enriched using this novel device.

Citation Format: Vasudha Murlidhar, Rishindra M. Reddy, Mina Zeinali, Svetlana Grabauskiene, Mostafa Ghannad-Rezaie, Max S. Wicha, Diane M. Simeone, Nithya Ramnath, Sunitha Nagrath. Radial flow microfluidic device for high-throughput affinity-based isolation of circulating tumor cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3069. doi:10.1158/1538-7445.AM2014-3069
Abstract 3099: Dual targeting of mTOR and Notch disrupts growth and promotes apoptosis in diffuse intrinsic pontine glioma
Authors: Taylor Isabella C. , Hutt-Cabezas Marianne , Weingart Melanie , Warren Kathy , Chang Howard , Nazarian Javad , Eberhart Charles G. , Raabe Eric H.
Published: May 2015

Diffuse intrinsic pontine gliomass (DIPGss) account for 10% of pediatric brain tumors and have a universally poor prognosis. Our laboratory has shown that targeting the NOTCH pathway in glioblastoma (GBM) with gamma secretase inhibitors (GSI), inhibits the growth and viability of tumor neurospheres. Primary DIPG as well as DIPG cell lines express have very high levels of NOTCH activity as measured by western blot and qPCR assays. AKT amplification is observed in primary DIPG, and TORC1/TORC2 activation occurs in DIPG cell lines as measured by western blot. The mTOR and NOTCH pathways are known to interact and alter cancer stem cell growth, stemness, and metabolism. We hypothesized that dual targeting of NOTCH and mTOR in DIPG would lead to decreased proliferation and increased apoptosis compared to targeting either pathway in isolation. In established DIPG cell lines, we observed that GSI treatment decreases NOTCH activity in a dose dependent manner as evidenced by decreased expression of NOTCH targets expression of Hes1 and Hey1 via as measured by western blot and qPCR assays. We also observed a dose-dependent reduction in DIPG proliferation and growth after gamma-secretase inhibition as measured by BrdU (Day 7, DMSO to 5 uM MRK003 had p value <0.05) and MTT assays (Day 5 and Day 7, DMSO to 2 uM and 5 uM MRK003 p value <0.05). However, inhibition of growth and increased apoptosis were not complete. We observed a similar decrease in proliferation and increase in apoptosis using the dual TORC1/TORC2 inhibitor PPT242. Combination therapy with MRK003 and PP242 led to significantly increased apoptosis compared to either treatment alone (cell cycle Sub-G1: DMSO 13.2% vs 1000nM PP242-5uM M003 28.9%). This data suggest that dual targeting of the mTOR and NOTCH pathways with GSI will decrease DIPG cell growth and proliferation, increase cell death, and reduce tumorigenicity.

Citation Format: Isabella C. Taylor, Marianne Hutt-Cabezas, Melanie Weingart, Kathy Warren, Howard Chang, Javad Nazarian, Charles G. Eberhart, Eric H. Raabe. Dual targeting of mTOR and Notch disrupts growth and promotes apoptosis in diffuse intrinsic pontine glioma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3099. doi:10.1158/1538-7445.AM2014-3099
Abstract 3100: Glial origin for MYCN-driven medulloblastoma and targeted prosenescence therapies
Authors: Bolin Sara M. , Lau Jasmine , Chen Justin , Savov Vasil , Persson Anders I. , Hede Sanna-Maria , Weiss William A. , Swartling Fredrik
Published: May 2015

MYCN-amplified medulloblastoma is a poor-prognosis childhood brain tumor with unknown cellular origin. Recently, we showed how MYCN overexpression could generate tumors with high penetrance from a glutamate transporter (GLT1) promoter in a transgenic model (GTML) of medulloblastoma. By using Rosa26-lsl-LacZ reporters we also showed that GLT1-positive neural stem cells represent presumed cells of tumor origin.

Transgenic GTML mice generate SHH-independent medulloblastoma 2-3 months after birth. Before tumor onset GTML mice presented significantly more proliferation in thalamic forebrain cells and in Bergmann glia in the cerebellum as compared to corresponding normal brain. Strikingly, adult GTML mice also show proliferative capacity in the Bergmann glia cell population in response to MYCN oncogene activity, further connecting this population to medulloblastoma development. Retroviral tagging using the RCAS/tv-a system marked BLBP- or GFAP-positive tumor initiating cells and expression analysis could further determine genetic profiles of glial origin.

Interestingly, MYCN levels and early proliferation of brain tumors could be reduced by specific CDK2-inhibition by Milciclib or by using the bromodomain inhibitor JQ1. Treatment studies revealed a need for sustained treatment over 7-10 days to effectively abolish tumor cell proliferation. Both treatment strategies induced tumor cell senescence as seen by SA-beta-gal staining and by downregulated levels of Lamin B1. Our data suggest that tumors generated arise from radial glia or Bergmann glia in this medulloblastoma model and that dual inhibition of CDK2 and bromodomains suppresses tumor growth by targeting MYCN.

Citation Format: Sara M. Bolin, Jasmine Lau, Justin Chen, Vasil Savov, Anders I. Persson, Sanna-Maria Hede, William A. Weiss, Fredrik Swartling. Glial origin for MYCN-driven medulloblastoma and targeted prosenescence therapies. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3100. doi:10.1158/1538-7445.AM2014-3100
Abstract 3107: The role of LIN28 in atypical teratoid rhabdoid tumor (ATRT) pathogenesis
Authors: Phi Ji Hoon , Choi Seung Ah , Kim Yong Hwy , Kim Young-Hoon , Park Chul-Kee , Wang Kyu-Chang , Kim Seung-Ki
Published: May 2015

Atypical teratoid rhabdoid tumor (ATRT) is a highly malignant brain tumor developing almost exclusively in children. It belongs to the embryonal brain tumor group which consists of primitive tumors recapitulating early embryogenesis of nervous system. It is known that loss of INI protein expression is the hallmark of ATRT pathogenesis. LIN28 is a key gene in embryonic development and maintenance of pluripotency in stem cells. Considering the primitive nature and young age onset of ATRT, LIN28 may be an important co-player in ATRT pathogenesis.

We explored the expression and functional role of LIN28 in ATRT. In tumor tissues, LIN28 is highly expressed in ATRT compared with medulloblastomas, another embroynal tumor, whereas primary let-7 microRNA is down-regulated in ATRT. ATRT also showed higher expression of CCND1 and MYC and lower expression of CDKN1C. Knockdown of LIN28 with siRNA in ATRT cell lines resulted decreased cell viability, proliferation, and migration capability. Suppression of CCND1 and MYC expression and enhanced expression of CDKN1C were also observed. Knockdown of LIN28 lead to decreased expression of other pulripotency genes (OCT4 and NANOG) and signature of mesenchymal-epithelial transition was observed after suppression of LIN28. We then introduced wild-type INI1 into ATRT cells by transfection. Restoration of INI in ATRT cell lines lead to decreased expression of LIN28 and CCND1.

These results showed that LIN28 is regulated by INI1 and that loss of INI1 protein in ATRT results in unopposed expression of LIN28 and related oncogenes such as CCND1, leading to tumorigenesis. Therefore, the strategic role of LIN28 in ATRT may be utilized as an important therapeutic target.

Citation Format: Ji Hoon Phi, Seung Ah Choi, Yong Hwy Kim, Young-Hoon Kim, Chul-Kee Park, Kyu-Chang Wang, Seung-Ki Kim. The role of LIN28 in atypical teratoid rhabdoid tumor (ATRT) pathogenesis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3107. doi:10.1158/1538-7445.AM2014-3107
Abstract 3133: The anti-tumor effects of acetazolamide and sulforaphane on bronchial carcinoids: Preclinical modeling and mechanism
Authors: Mokhtari Reza Bayat , Islam Syed S. , Baluch Narges , Aitken Karen , Kumar Sushil , Cheng Hai-Ling Margaret , Yazdanpanah Mehrdad , Adeli Khosrow , Zhou Yuanxiang , Cutz Ernest , Yeger Herman
Published: May 2015

Background: The prognosis of patients with metastatic bronchial carcinoid remains poor despite current conventional and targeted therapies. Here we evaluated the therapeutic potential of acetazolamide (AZ; a pan carbonic anhydrase inhibitor affecting pH regulation and homeostasis) and sulforaphane (SFN; a natural isothiocyanate compound targeting multiple pathways in cancer cells), for their anti-cancer properties. Methods: In vitro and in vivo studies were conducted on H-727 (typical carcinoid) and H-720 (atypical carcinoid) bronchial carcinoid cell lines. We developed a lung orthotopic bronchial carcinoid tumor xenograft model in NOD/SCID mice. Results: AZ and/or SFN significantly inhibited cell viability and clonogenic capacity in a dose-dependent manner (0-80 μM, 48 hours and 7 days). AZ and/or SFN downregulated phosphoH3, Ki67, EPCAM, CA9, Akt1 and upregulated p21 and Nrf2 proteins compared to controls as confirmed by Western blot. Upregulation of Nrf2 gene expression was confirmed by qPCR. AZ and/or SFN significantly reduced xenograft growth and serotonin content after two weeks treatment. In the lung orthotopic model, MR imaging at 3 Tesla precisely identified growth of H-727 injected cells in the ipsilateral side, and revealed liver metastasis as confirmed by histology. A tumor initiating cell (TIC) fraction isolated under stem cell culture conditions showing significantly enhanced tumorigenicity was also studied. Conclusions: AZ and/or SFN inhibited tumor survival, proliferation, invasiveness, serotonin secretion and tumorigenic potential of bronchial carcinoid cell lines. Since the combination of AZ+SFN was more effective than either single agent, we postulate that AZ potentiates the effects of SFN by inhibiting PI3K/AKT, which could enhance the inhibitory effect of SFN on P21, Ki67 and phosphoH3. Interestingly, Nrf2 upregulation by both AZ and by SFN suggested a potent antioxidant response. The lung orthotopic tumor model of bronchial carcinoids permits study of carcinoid metastatic progression. As the doses used in this study are clinically bioavailable we suggest that AZ and SFN may have promising potential for carcinoid therapy and resolution of the carcinoid syndrome.

Citation Format: Reza Bayat Mokhtari, Syed S. Islam, Narges Baluch, Karen Aitken, Sushil Kumar, Hai-Ling Margaret Cheng, Mehrdad Yazdanpanah, Khosrow Adeli, Yuanxiang Zhou, Ernest Cutz, Herman Yeger. The anti-tumor effects of acetazolamide and sulforaphane on bronchial carcinoids: Preclinical modeling and mechanism. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3133. doi:10.1158/1538-7445.AM2014-3133
Abstract 3138: IL-6/Stat3 signaling is an indispensable modulator of oncogene-induced cellular senescence
Authors: Pencik Jan , Schlederer Michaela , Hassler Melanie , Gruber Wolfgang , Aberger Fritz , Kennedy Richard , Walker Stephen , Rose-John Stephan , Poli Valeria , Eferl Robert , Esterbauer Harald , Aksoy Osman , Herac Merima , Mazal Peter , Haitel Andrea , Susani Martin , Moriggl Richard , Culig Zoran , Kenner Lukas
Published: May 2015

IL-6/Stat3 signaling plays a role as a proto-oncogene in various tumors including prostate cancer, where IL-6 has been explored as therapeutic target. Deficiency of Pten, one of the most commonly mutated genes in cancer, directly triggers a senescence program critically depending on the p19Arf-p53 fail-safe pathway. We identified a novel and unexpected tumor suppressive role of IL-6/Stat3 signaling in a Pten-deficient murine prostate cancer model. Our data provide evidence that activation of IL-6/Stat3 signaling axis is implicated in oncogene-induced senescence (OIS). Strikingly, genetic ablation of IL-6 strongly promoted prostate cancer initiation, progression and metastasis in Pten-deficient mice. Mechanistically, IL6/Stat3 signaling regulates p19Arf-p53-induced senescence by modulating expression of the ubiquitin ligase MDM2 in pre-neoplastic cells. Critically, in prostate cancer patients low expression of Stat3 or p14Arf, the human homologue of p19Arf, correlates with poor survival. Therefore, the IL-6/Stat3 signaling axis may represent a novel molecular target for senescence-based cancer therapies.

Citation Format: Jan Pencik, Michaela Schlederer, Melanie Hassler, Wolfgang Gruber, Fritz Aberger, Richard Kennedy, Stephen Walker, Stephan Rose-John, Valeria Poli, Robert Eferl, Harald Esterbauer, Osman Aksoy, Merima Herac, Peter Mazal, Andrea Haitel, Martin Susani, Richard Moriggl, Zoran Culig, Lukas Kenner. IL-6/Stat3 signaling is an indispensable modulator of oncogene-induced cellular senescence. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3138. doi:10.1158/1538-7445.AM2014-3138
Abstract 3141: Epithelial-to-mesenchymal transition and therapy resistance in BRCA1-associated breast cancer
Authors: Miltenburg Martine Van , Jonkers Jos
Published: May 2015

Despite progress in the treatment of breast cancer, patients with triple-negative breast cancer (TNBC) have limited means for therapy. Since TNBCs do not express HER2, estrogen and progesterone receptors, TNBC patients cannot be treated with Herceptin or endocrine therapy. TNBCs frequently harbor defects in homologous recombination (HR) due to (epi)genetic inactivation of BRCA1, making them sensitive to the clinical PARP1 inhibitor olaparib. However, long-term treatment of BRCA1-deficient mouse mammary tumors with olaparib results in drug resistance. The growing awareness that epithelial-to-mesenchymal transition (EMT) may influence therapy response prompted us to investigate whether olaparib sensitivity of BRCA1-deficient TNBCs is affected by MET, a known EMT inducer that is over-expressed in TNBC and associated with poor survival. For this purpose we have developed a breast cancer GEMM-ESC pipeline, using female GEMM-ESCs derived from our well-validated K14cre;Brca1F/F;Trp53F/F (KB1P) mouse model, of which females spontaneously develop BRCA1-deficient TNBC due to cre-mediated deletion of Brca1 and Trp53 in epithelial tissues. The MET proto-oncogene, was introduced in the Col1a1 locus and resulting KB1P-MET ESCs were injected into blastocysts and good quality chimeras were monitored for mammary tumor formation. Our preliminary data show that BRCA1-deficient mouse mammary tumors with engineered overexpression of MET show accelerated growth, undergo EMT and show intrinsic resistance to olaparib. The underlying mechanisms are, however, unclear. Currently we are studying the impact of EMT-regulators on BRCA1-associated mammary tumorigenesis and assess the contribution of EMT-regulators to olaparib resistance in genetically engineered mouse models of BRCA1-associated breast cancer. Together, these studies will provide novel insights into the roles of EMT regulators in BRCA1-associated breast tumor development, metastasis and therapy resistance.

Citation Format: Martine Van Miltenburg, Jos Jonkers. Epithelial-to-mesenchymal transition and therapy resistance in BRCA1-associated breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3141. doi:10.1158/1538-7445.AM2014-3141
Abstract 316: Modifying autophagy through combination treatments as a potential therapeutic strategy in head and neck squamous cell carcinoma (HNSCC)
Authors: Ahmed Omar G. , Kuo Wen-Liang , Wei Tai-Fen , Messer Jeannette S. , Sharifi Marina , Nagilla Madhavi , Macleod Kay , Cohen Ezra E.W.
Published: May 2015

Introduction: Autophagy, a catabolic process, can play a crucial role in cancer cell survival. Modifying this process has shown to be an effective mechanism of inducing cell death. In order to explore this concept, we induced autophagy with one agent (Akt-inhibitor MK-2206), and decreased autophagosomal trafficking with other agents (Paclitaxel and Nocadazole) by disrupting the microtubule networks. We hypothesized that by modifying autophagy through this combination, it would lead to an accumulation of autophagosomes and eventual cell death in a synergistic manner.

Methods: SCC 61 and Cal 27 HNSCC cell lines were used to explore this hypothesis. SCC 61 cells were transduced with an m-Cherry GFP LC3B vector in order to detect autophagosomes under both fixed and live cell confocal microscopy. Cell viability and apoptosis assays were performed. A siRNA ATG 7 KO SCC 61 cell line was used to detect if in fact autophagy was important for this therapeutic approach.

Results: There was an accumulation of autophagosomes with the combination of an Akt inhibitor and microtubule disrupters. A decrease in fusion of autophagosome to lysosome was seen when cells were treated with an agent, which disrupted the microtubule networks (Paclitaxel) but even more dramatically when treated with the combination (MK-2206 and Paclitaxel). Moreover, accumulation of autophagosomes occurred prior to induction of apoptosis with combination treatment. These effects were decreased with siRNA ATG 7 KO in SCC 61 cells, which were more resistant to combination treatment compared to control.

Discussion: Manipulating autophagy with Akt inhibition (induction) and Paclitaxel (decreasing autophagic trafficking) leads to an accumulation of autophagosomes and eventual cell death in a synergistic manner. This therapeutic approach of altering the normal autophagic process warrants further investigation.

Citation Format: Omar G. Ahmed, Wen-Liang Kuo, Tai-Fen Wei, Jeannette S. Messer, Marina Sharifi, Madhavi Nagilla, Kay Macleod, Ezra E.W. Cohen. Modifying autophagy through combination treatments as a potential therapeutic strategy in head and neck squamous cell carcinoma (HNSCC). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 316. doi:10.1158/1538-7445.AM2014-316
Abstract 3161: Non-cell autonomous regulation of collective invasion be an epigenetically distinct subpopulation of tumor cells
Authors: Prechtl Amanda , Westcott Jill , Dang Tuyen , Maine Erin , Pearson Gray
Published: May 2015

Diverse genetic and epigenetic traits can promote variant behaviors in subpopulations of cells within primary tumors. In some cases, these heterogeneous subpopulations may compete against each other for clonal dominance to improve tumor fitness. By comparison, the extent to which tumor cell subpopulations cooperate during malignant progression is not well understood. Here, we find that a commensal relationship can exist between epigentically distinct subpopulations of tumor cells during collective invasion.

Using quantitive phenotypic analysis and live-cell imaging, we discovered that a subpopulation of cells, termed trailblazer cells, has an enhanced ability to collectively invade. Trailblazer phenotype was heritable and trailblazer subpopulations were derived from 5 triple-negative breast cancer cell lines. The percentage of trailblazers cells within a population ranged from between 0.5% and 90% of the parental population. Gene expression profiling identified a 29-gene expression signature that distinguished trailblazer cells from non-trailblazer cells and identified patients with poor outcome, A cohort of genes trailblazer signature genes were necessary for the formation of actin-rich projections that facilitate path generation during collective invasion. In addition, the trailblazer gene DOCK10 was necessary for spontaneous metastasis to the lung. The path generating function of a small subpopulation of trailblazer cells was sufficient to induce the collective invasion of large population of naturally occurring non-trailblazer cells in organotypic culture. Trailblazer cells were also sufficient to induce the invasion of a mouse model of ductal carcinoma in situ. Taken together, our results suggest that a rare subpopulation of tumor cells with an enhanced ability to collectively invade can promote metastatic progression through cell autonomous and non-cell autonomous mechanisms. Thus, our results support a paradigm shift towards identifying both the cell autonomous and the non cell-autonomous regulatory mechanisms of cell biological processes within heterogeneous tumors to understand neoplastic progression and develop new intervention modalities.

Citation Format: Amanda Prechtl, Jill Westcott, Tuyen Dang, Erin Maine, Gray Pearson. Non-cell autonomous regulation of collective invasion be an epigenetically distinct subpopulation of tumor cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3161. doi:10.1158/1538-7445.AM2014-3161
Abstract 3168: Tumor cells express genome-derived DNA in the cytosol
Authors: Shen Yu J. , Bert Nina L. , Koo Christine X. , Samantha Ho S. , Ishii Ken J. , Raulet David H. , Gasser Stephan
Published: May 2015

Type I interferons (IFNs) are secreted by infected cells in response to the recognition of nucleic acids. DNA damage and the ensuing DNA damage response also induce the expression of IFNs by poorly understood mechanisms. Here we show the presence of extramitochondrial single-stranded (ss) and double-stranded (ds) DNA in the cytosol of mouse and human tumor cells. The DNA only partially co-localized with autophagosomes, stress granules or lysosomes, but a majority was associated with mitochondria. Genotoxic agents increased the amount of DNA in the cytosol of tumor cells with low levels of constitutive cytosolic DNA. Cloning of ssDNA and dsDNA present in the cytosol of mouse tumor cells showed that at least some of the cytosolic DNA is derived from unique genomic loci. Cloned cytosolic DNA sequences often contained genomic retroelements. In silico analysis of the cloned DNA indicated that cytosolic DNA is predicted to form putative triplex DNA structures. Overexpression of Rnaseh1, which degrades intermolecular triplex structures called R-loops, reduced the levels of cytosolic ssDNA and dsDNA, while overexpression of Trex1, the major 3’-5’ DNA exonuclease, decreased the amount of cytosolic ssDNA but not dsDNA. Upregulation of IFNs in response to genotoxic agents was impaired in cells expressing Rnaseh1 or Trex1. In summary, we provide evidence that DNA damage in tumor cells induces the accumulation of genomic DNA in the cytosol and the production of type I IFNs in many tumor cells, which may contribute to immunosurveillance of cancers.

Citation Format: Yu J. Shen, Nina Le Bert, Christine XE Koo, Ho SW Samantha, Ken J. Ishii, David H. Raulet, Stephan Gasser. Tumor cells express genome-derived DNA in the cytosol. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3168. doi:10.1158/1538-7445.AM2014-3168
Abstract 3169: APOBEC-mediated cytosine deamination is a prominent mutagenic mechanism in human papillomavirus-driven cancer
Authors: Henderson Stephen , Chakravarthy Ankur , Su Xiaoping , Boshoff Chris , Fenton Tim R.
Published: May 2015

APOBEC3B cytosine deaminase activity has recently emerged as a significant mutagenic factor in human cancer. APOBEC activity is induced in virally infected cells and APOBEC signature mutations occur at high frequency in cervical cancers, over 99% of which are caused by high risk variants of Human Papillomavirus (HPV). We tested the hypothesis that APOBEC-mediated mutagenesis plays a particularly important role in HPV-associated cancer by analysing head and neck squamous cell carcinoma (HNSCC), a tumor type for which exome sequence data from The Cancer Genome Atlas project are available from both HPV+ and HPV- variants. We show that HPV+ tumors express more APOBEC3B and harbor a higher proportion of APOBEC signature mutations than HPV- tumors. The APOBEC mutational signature is absent from hepatitis virus-associated hepatocellular carcinoma, indicating it is not simply a consequence of the immune response to persistent viral infection. We also uncover a strong linear relationship between APOBEC signature mutations and APOBEC-independent mutations in both HNSCC and in breast cancer, such that in high APOBEC subsets (HPV+ HNSCC and HER2-amplified breast cancer), the proportion of mutations due to APOBEC activity is consistently increased, regardless of the overall mutational burden in the tumor. Finally, HPV+ HNSCC and cervical cancer show particularly strong enrichment for APOBEC signature mutations in known cancer genes, implicating APOBEC activity as a key driver of HPV-induced transformation.

Citation Format: Stephen Henderson, Ankur Chakravarthy, Xiaoping Su, Chris Boshoff, Tim R. Fenton. APOBEC-mediated cytosine deamination is a prominent mutagenic mechanism in human papillomavirus-driven cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3169. doi:10.1158/1538-7445.AM2014-3169
Abstract 3192: The environmental estrogen bisphenol A (BPA) regulates mammary gland stem cells
Authors: Nichols Cydney , Ding Xiangming , Miranda-Carboni Gustavo , Krum Susan Amy
Published: May 2015

A study by the Centers for Disease Control revealed detectable levels of the environmental toxin Bisphenol A (BPA) in urine samples from over 92% of people in the NHANES (National Health and Nutrition Examination Survey) study. BPA is a small molecule used in the polymerization of polycarbonate plastics. These plastics are widely used in food containers, water bottles, dental fillings and toys, among many other products. BPA is similar to the synthetic estrogen diethylstilbesterol (DES) and can bind to estrogen receptor alpha (ERα) or estrogen receptor beta (ERβ). Because BPA is lipophilic and has been detected in mammary gland fat in humans, we hypothesize that BPA is an estrogen mimic in the stromal adipocytes in the breast and can induce stem cell proliferation and survival, leading to breast tumor formation. Indeed, BPA increases the size and number of mammospheres from normal mouse mammary gland and from human MCF7 breast cancer cells. Adipocytes co-cultured with mammospheres increased the size of the spheres, and BPA further increased the size of adipocyte co-cultured mammospheres. BPA upregulates the stem cell markers Nanog, OCT4 and SOX2 in mammospheres. ERα and pCREB were shown to bind to an enhancer downstream of the SOX2 gene after BPA treatment. Finally, BPA increased the size of tumor xenografts in NUDE mice. Together these experiments demonstrate that BPA may induce breast cancer via ERα and pCREB regulation of breast cancer stem cells.

Citation Format: Cydney Nichols, Xiangming Ding, Gustavo Miranda-Carboni, Susan Amy Krum. The environmental estrogen bisphenol A (BPA) regulates mammary gland stem cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3192. doi:10.1158/1538-7445.AM2014-3192
Abstract 3198: Extract from Scutellaria baicalensis Georgi inhibits prostate cancer growth in bone
Authors: Li Chaoqian , Guo Hongwei , Lu Yi , Dai Jinlu , Keller Evan , Zhang Jian
Published: May 2015

Prostate cancer (PCa) frequently metastasizes to bone forming predominantly osteoblastic lesions with underlined osteolytic components. Because current therapies are generally ineffective in PCa skeletal metastases, patients seek alternative medicines such as herbal medicines, which have been used for many centuries in Asian countries. The purpose of this study was to identify Chinese herbal medicines that may be effective in PCa skeletal metastasis. We first screened 130 Chinese herbs (ethanol extracts) for anti-proliferation effects by non-radioactive cell proliferation assay in LNCaP and C4-2B PCa cells. We found five extracts with anti-proliferation activity including extract from Scutellaria baicalensis Georgi (Huang Qin, HQ), which had the strongest effect. We next evaluated HQ's ability to induce apoptosis of LNCaP and C4-2B cells. HQ, in a dose-dependent manner, induced apoptosis of both cell lines based on TUNEL assay. In addition, HQ induced apotosis-related gene caspase-3 and suppressed bcl-2 expressions in both cell lines. Therefore, we tested if HQ (1mg per mouse three times a week for 8 weeks intraperitoneally) could diminish establishment of skeletal metastases in mice. We injected C4-2B cells into tibia of SCID mice. The animals were randomized into two groups to receive either HQ or vehicle only (n=8/group). At 8 weeks post-tumor injection, mice were sacrificed and tumor establishment in the skeleton was determined using radiography, dual energy x-ray absorptiometry and histology. Radiographic and histological lesions were present in 7/8 vehicle-treated mice and in 6/8 HQ-treated mice. However, the radiographically- and histologically-determined areas of the tumors in the HQ-treated mice were approximately 47% that of the vehicle-treated animals. We conclude that HQ has efficacy for inducing PCa cells apoptosis in vitro and has the ability to diminish growth of PCa in murine bone. Supported by NSF key project 81130046, NSF projects 81171993 and 81272415.

Citation Format: Chaoqian Li, Hongwei Guo, Yi Lu, Jinlu Dai, Evan Keller, Jian Zhang. Extract from Scutellaria baicalensis Georgi inhibits prostate cancer growth in bone. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3198. doi:10.1158/1538-7445.AM2014-3198
Abstract 3216: Anti-proliferative properties of Euphorbia mauritanica medicinal plant against breast cancer
Authors: Choene Mpho S. , Motadi Lesetja R.
Published: May 2015

Over the decades, the increased interest in the use of natural resources in pharmaceutical and phytotherapeutic research has led to manufacture of drugs (including anti-cancer drugs) derived from natural sources With our increased understanding of the molecular mechanisms underlying cancer progression and cell death, it is therefore necessary to test if there are any natural products that can be used to act as antitumor agents. As breast cancer continues to be the leading cause of cancer in females, we aimed to exploit the use of South African traditional medicine, Euphorbia mauritanica as a tool for anti breast cancer therapy. Euphorbia mauritanica was tested for anti-proliferative properties against MCF-7 and Cama-1 breast cancer cell lines. The following solvents were used to extract active compounds from E. mauritanica: n-hexane, dichloromethane, chloroform, ethyl acetate, acetone, methanol and butanol. A real time cell analyzer (Xcelligence) was used to monitor cell growth over a period of 48 hours following treatment of cells with the extracts. Butanolic extracts showed the highest level of cytotoxicity on both MCF-7 and Cama-1 cell lines with IC50 of 15 and 30 µg/ml respectively. These were followed by hexanolic extracts with IC50 of 30 and 50 µg/ml and methanolic extracts with IC50 of 50 and 100 µg/ml. Flow cytometry using annexin V was further employed to determine if cell death was as a result of apoptosis and the data confirmed that this was most likely the case. On investigating whether the observed apoptosis was via p53 mediated pathway, western blot analysis of p53, bcl-2, caspase 9, caspase3, RBBP6 and mdm2 showed that treatment with the 3 extracts did not have a significant effect on any of these genes, suggesting that their mode of apoptosis induction maybe through an alternative apoptotic pathway.

Citation Format: Mpho S. Choene, Lesetja R. Motadi. Anti-proliferative properties of Euphorbia mauritanica medicinal plant against breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3216. doi:10.1158/1538-7445.AM2014-3216
Abstract 3218: Zyflamend, a multi-herbal product, selectively inhibits the growth of triple negative breast cancer cells in vitro
Authors: Gutierrez-Barrera Angelica M. , Arun Banu K. , Yang Peiying , Cartwright Carrie
Published: May 2015

Triple negative breast cancer (TNBC), a subpopulation of breast cancer that has a high mortality rate, recently has been shown to be quite diverse with approximately 7 different molecular subtypes. As a result, treatment with an agent that can potentially target multiple pathways might be an effective approach. Zyflamend (Zy), a unique herbal preparation consisting of 10 concentrated herbal extracts, has been shown to suppress the proliferation of various cancer cells including prostate, melanoma, and bladder cancers. However, its role in TNBC has not been investigated. To examine its anticancer activity in TNBC, we utilized a crystal violet staining assay to determine the proliferation of cells, FACS analysis for cell cycle and apoptosis and gene/protein expression analysis to delineate the plausible mechanism of action. Among a number of breast cancer cell lines including MCF-7, SUM149, MDMB231, BT549 and HCC1937, Zy exerted stronger inhibitory effect in all TNBC cells with IC50 values ranging between 400-800μg/ml (0.5-1 μl/ml) whereas MCF-7, an estrogen/progesterone receptor positive cell line, required 1000μg/ml (1.5μl/ml). Similarly, the morphologies of SUM149, MDAMB231, and BT549 cell lines were notably disrupted by Zy treatment (400μg/ml) when these cells were cultured using three dimensional techniques. FACS analysis showed that there was a dramatic shift to subG1 phase, suggesting cells might undergo apoptosis. Reverse Phase Proteomic Array indicated that proteins affecting the cell cycle progression, cell junction regulation, and cell signaling were altered in BT549 and HCC1937 by 24 hr Zy treatment (800μg/ml).. When compared to the vehicle control, gene expression analysis showed that several inflammatory genes were downregulated by at least 50% and these included 5- and 12-lipooxygenase, leukotriene receptors, TNF receptor, and NF-κB in HCC1937 (800μg/ml), MDAMB231(800μg/ml) and SUM149 (400μg/ml) cells. Taken together, our preliminary data suggests that Zy inhibits TNBC proliferation by inhibiting inflammation, regulating cell cycle, and inducing cell death. Further studies are ongoing to evaluate these effects in in vivo triple negative breast cancer models.

Citation Format: Angelica M. Gutierrez-Barrera, Banu K. Arun, Peiying Yang, Carrie Cartwright. Zyflamend, a multi-herbal product, selectively inhibits the growth of triple negative breast cancer cells in vitro. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3218. doi:10.1158/1538-7445.AM2014-3218
Abstract 3225: LEDGF IBD domain represents therapeutic target for MLL leukemia and HIV
Authors: Cierpicki Tomasz , Murai Marcelo J. , Pollock Jonathan , Purohit Trupta , He Shihan , Yokom Adam , Hess Jay L. , Muntean Andrew G. , Grembecka Jolanta
Published: May 2015

Lens epithelium-derived growth factor (LEDGF) is a chromatin associated protein implicated in cell survival, cancer, autoimmune diseases and HIV pathogenesis. LEDGF is also involved in recurring chromosomal translocations with nucleoporin NUP98 in acute leukemia, and the LEDGF/p75 isoform is consistently upregulated in a subset of acute myeloid leukemias (AML) resistant to chemotherapy. Moreover, it has been established that LEDGF is an essential co-factor required for oncogenic activity of MLL fusion proteins in leukemia. LEDGF interacts simultaneously with MLL and menin and is necessary for up-regulation of HOXA9 gene and for leukemogenic transformation by MLL fusion proteins in vivo. Therefore, LEDGF represent a valuable molecular target for therapeutic intervention as a novel targeted therapy for MLL leukemia patients. Furthermore, targeting LEDGF may represent an attractive alternative to inhibition of the menin-MLL interaction as it will allow preserving the function of menin, a known tumor suppressor in endocrine tissues.

We determined the solution structure of MLL fragment bound to LEDGF IBD domain and identified a novel hydrophobic motif within MLL, which we called IBM2, that is required for high affinity interaction with LEDGF. Point mutations within IBM2 abolished leukemogenic activity of MLL-AF9, indicating that IBM2 represents a critical site for formation of a high affinity menin-MLL-LEDGF complex. Furthermore, we found that short peptide corresponding to IBM2 binds to IBD domain and disrupts the interaction of LEDGF with the menin-MLL complex, providing a proof of concept that the novel interface on IBD domain we identified represents a druggable site for small molecule intervention.

LEDGF plays also an essential role in pathogenesis of HIV-1 virus and is required for integration of viral cDNA. Targeting HIV integrase to disrupt the interaction with LEDGF has been recognized as an attractive approach to develop new anti-viral agents. Importantly, the new MLL binding site on IBD domain we found overlaps with the binding site of HIV integrase. Therefore, targeting the IBM2 site on IBD may represent a novel approach to target the LEDGF-integrase interaction. In summary, our findings pave the way towards development of new therapeutic agents with dual applications for both MLL leukemias and HIV.

Citation Format: Tomasz Cierpicki, Marcelo J. Murai, Jonathan Pollock, Trupta Purohit, Shihan He, Adam Yokom, Jay L. Hess, Andrew G. Muntean, Jolanta Grembecka. LEDGF IBD domain represents therapeutic target for MLL leukemia and HIV. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3225. doi:10.1158/1538-7445.AM2014-3225