bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2452: Exosomes as mediators of paracrine signalling that promote invasive behavior in rhabdomyosarcoma
Authors: Ghayad Sandra E. , Rammal Ghina , Ghamloush Farah , Basma Hussein , Saab Raya 
Published: July 2016

Abstract
Exosomes are small membranous vesicles secreted into body fluids by multiple cell types, including tumor cells. Tumor exosomes contain intact and functional protein, mRNA and miRNA that may alter the cellular environment to favor tumor growth. Rhabdomyosarcoma (RMS) is an aggressive childhood soft tissue tumor, with two distinct subtypes, alveolar (ARMS) and embryonal (ERMS) histology. ARMS tumors are characterized in the majority of cases by a fusion oncoprotein PAX3-FOXO1, thought to be an initiating factor in tumorigenesis. To date, no studies have been performed to investigate the possible role or content of exosomes in paracrine signaling in RMS.
In the present study, we isolated and characterized exosomes secreted from RMS cells, using 3 ERMS (fusion oncoprotein negative) and 2 ARMS (fusion oncoprotein positive) cell lines. RNA analysis showed that small RNA were enriched in RMS-derived exosomes, therefore we focused on evaluating the miRNA content. Array expression analysis showed that exosome miRNA clustered together well, and to a higher extent than cellular miRNA, in ARMS cell lines. Similarly, in the 2 ERMS cell lines that had mutant p53, exosome miRNA clustered together and the pattern of expression was very different from the corresponding cellular miRNA. ARMS and ERMS exosome-enriched miRNA were different, and only 2 miRNA were found to be common among both; putative targets are implicated in cancer and inflammation. Functionally, using in vitro assays, we found that both ERMS- and ARMS-derived exosomes significantly increased the cellular migration and invasion of normal human fibroblasts, and had a positive effect on viability and proliferation of both fibroblasts and RMS cells. In vivo, Matrigel plug assay showed that RMS-derived exosomes had a positive effect on the migration and invasion of stromal cells, suggesting a positive role on angiogenesis.
We conclude that RMS-derived exosomes can exert specific paracrine effects on recipient cells, enhancing cell viability as well as invasive properties of fibroblasts and stromal cells, and therefore is likely to play a role in promoting RMS angiogenesis and metastasis. Ongoing studies are aimed at directly assessing the role of RMS-derived exosomes in clinical angiogenesis and metastasis, using in vivo murine models, in addition to dissecting the role of specific enriched miRNA on recipient cell biology.
Citation Format: Sandra E. Ghayad, Ghina Rammal, Farah Ghamloush, Hussein Basma, Raya Saab. Exosomes as mediators of paracrine signalling that promote invasive behavior in rhabdomyosarcoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2452.
Abstract 246: Role for ATP7A copper transporter in cisplatin resistance, tumorigenesis and metastasis
Authors: Shanbhag Vinit , Gudekar Nikita 
Published: July 2016

Abstract
Copper is a trace metal with a ready capacity to gain or donate electrons. This property is harnessed by numerous enzymes to perform vital functions in the body. In humans, copper is required for various biochemical processes including cellular respiration, connective tissue development, iron transport, and pigmentation. The same redox property which makes copper useful can also have deleterious effects if the proper balance is not maintained. Hence a delicate balance of copper should be maintained in the body. Cellular copper homeostasis is maintained by several different proteins. Ctr1 (copper transporter 1) has high affinity for copper and aids in copper uptake into the cell. ATP7A and ATP7B are copper exporting ATPases, which share 60% identity, are functionally homologous. Under low intracellular copper concentrations, ATP7A is localized to the TGN (trans-Golgi network), where it transports copper to newly synthesized cuproenzymes. Under elevated copper concentrations, ATP7A traffics to post TGN vesicles and to the plasma membrane, subsequently releasing the copper load by fusion with the plasma membrane.
There are emerging studies implicating a role of ATP7A in resistance against the platinum-based chemotherapy agent, cisplatin, which is widely used to treat cancer. Previous studies have correlated ATP7A expression to the sensitivity of cultured cells to cisplatin. Here, we report that deletion of the Atp7a gene in isogenic RAS-transformed mouse embryonic fibroblast (MEF) cells not only confers sensitivity to cisplatin, but markedly prevents tumor formation in the absence of chemotherapy agent. Deletion of Atp7a in the breast cancer cell line, 4T1, was also found to suppress tumorigenesis and markedly reduce metastasis to the lungs. The ATP7A knockout 4T1 cells showed a significant decrease in Lysyl Oxidase (LOX) activity as compared to the 4T1WT cells. Given the numerous studies showing that LOX family involved in breast tumor metastasis, ATP7A might play a role in tumor progression by virtue of its requirement for metallating LOX. The ATP7A knockout 4T1 cells exhibited reduced survival as compared to the 4T1WT cells in the presence of physiological concentrations of hydrogen peroxide or hypoxia, suggesting that hyper-accumulation of copper sensitizes these cells to ROS production. Taken together, these findings identify the ATP7A copper transporter at the nexus of platinum-drug resistance, tumorigenesis and metastatic pathways, underscoring its potential as a therapeutic drug target at multiple stages of carcinogenesis.
Citation Format: Vinit Shanbhag, Nikita Gudekar. Role for ATP7A copper transporter in cisplatin resistance, tumorigenesis and metastasis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 246.
Abstract 2464: Disrupting the epigenetic modifier HMGA2 in DIPG and GBM inhibits tumor invasion, growth and tumorigenicity
Authors: Kaur Harpreet , Hütt-Cabezas Marianne , Taylor Isabella , Weingart Melanie , Rodriguez Fausto , Eberhart Charles G. , Raabe Eric H. 
Published: July 2016

Abstract
Diffuse intrinsic pontine glioma (DIPG) and glioblastoma (GBM) are lethal, incurable brain tumors with poor prognosis. Identifying and targeting novel molecular markers regulating tumor invasion and growth can lead to development of better therapies. HMGA2, a minor-groove DNA-binding protein, is a transcriptional modulator in normal and cancer stem cells. We hypothesized that HMGA2 contributes to pediatric high grade glioma invasion and tumorigenicity through its ability to alter the transcription of large numbers of genes. We found increased expression of HMGA2 in a subset of GBM and DIPG tumors by western blotting and immunohistochemistry. We confirmed this result in multiple patient-derived tumor cell lines, including 3 DIPG neurosphere cell lines. Lentiviral short hairpin RNA (shRNA)-mediated reduction of HMGA2 in GBM cells significantly reduced invasion in transwell assay and colony formation in soft agar assay (shHMGA2 vs. shControl, P&lt;0.01). Similarly, shRNA mediated suppression of HMGA2 in DIPG cell lines reduced proliferation as measured by BrdU incorporation, reduced invasion by transwell assay and increased apoptosis by cleaved caspase-3 (CC-3) immunofluorescence (shHMGA2 vs. shControl, P&lt;0.01). Pharmacological inhibition of HMGA proteins using the DNA minor-groove binding drug Netropsin significantly inhibited growth (BrdU assay) and increased apoptosis (CC-3 immunofluorescence) of DIPG cell lines (P&lt;0.01). Mice bearing orthotopic GBM xenograft cell lines transduced with HMGA2 shRNA lived longer (median survival = 108 days) compared to control shRNA (67.5 days, P&lt;0.0001 by log-rank analysis). Our results suggest an oncogenic role of HMGA2 in promoting DIPG and GBM invasion and growth, identifying HMGA2 as a potential therapeutic target in these devastating tumors. Netropsin or other minor groove binding agents may be effective therapeutics for pediatric high-grade gliomas.
Citation Format: Harpreet Kaur, Marianne Hütt-Cabezas, Isabella Taylor, Melanie Weingart, Fausto Rodriguez, Charles G. Eberhart, Eric H. Raabe. Disrupting the epigenetic modifier HMGA2 in DIPG and GBM inhibits tumor invasion, growth and tumorigenicity. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2464.
Abstract 2468: Combined targeting of the EWS/ETS transcriptional program by BET bromodomain and PI3K pathway inhibition blocks tumorigenicity and increases apoptosis in Ewing sarcoma
Authors: Hensel Tim , Giorgi Chiara , Becker-Dettling Fiona , Calzada-Wack Julia , Neff Frauke , Buch Thorsten , Schmidt Oxana , Schäfer Beat W. , Burdach Stefan , Richter Günther HS 
Published: July 2016

Abstract
Ewing sarcomas (ES) are highly malignant bone or soft tissue tumors. Genetically, ES are defined by balanced chromosomal EWS/ETS translocations that give rise to chimeric proteins (EWS-ETS), which generate an oncogenic transcriptional program associated with altered epigenetic marks throughout the genome.
By use of an inhibitor (JQ1) blocking BET bromodomain binding proteins (BRDs) we strikingly observed a strong down-regulation of the predominant EWS-ETS protein EWS-FLI1 in a dose dependent manner. This was further enhanced by co-treatment with an inhibitor (BEZ235) of the PI3K pathway. Microarray analysis revealed JQ1 treatment to block a typical ES associated expression program. The effect on this expression program was mimicked by RNA interference of BRD3 or BRD4 expression but not by BRD2 blockade, indicating that the EWS-FLI1 mediated expression profile is at least in part mediated via such epigenetic readers.
JQ1 treatment not only suppressed an ES specific expression profile but also blocked contact dependent and independent proliferation of different ES lines. But subsequent analysis of proliferation after transient knockdown of either BRD3 or BRD4 did not recapitulate inhibition of proliferation as observed after JQ1 treatment, indicating the necessary simultaneous blockade of both proteins. However, inhibition of proliferation after JQ1 treatment was due to a partial G1 arrest and S phase elongation of the cell cycle. In addition, induction of apoptosis as demonstrated by PARP1-, CASP7-cleavage and increased CASP3 activity significantly contributed to the reduction of the proliferative ability of ES lines. Single or combination treatment with the PI3K/mTOR inhibitor BEZ235 increased apoptosis of ES cell lines although single treatment with BEZ235 was less effective than JQ1 application. Consequently, tumor development was dose dependently suppressed with increased formation of apoptotic bodies in a xeno-transplant model in immune deficient mice, overall indicating that ES may be susceptible to treatment with epigenetic inhibitors blocking BET bromodomain activity and the associated pathognomonic EWS-ETS transcriptional program.
Citation Format: Tim Hensel, Chiara Giorgi, Fiona Becker-Dettling, Julia Calzada-Wack, Frauke Neff, Thorsten Buch, Oxana Schmidt, Beat W. Schäfer, Stefan Burdach, Günther HS Richter. Combined targeting of the EWS/ETS transcriptional program by BET bromodomain and PI3K pathway inhibition blocks tumorigenicity and increases apoptosis in Ewing sarcoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2468.
Abstract 2469: The role of L1 in proliferation and chemoresistance of retinoblastoma
Authors: Jo Dong Hyun , Lee Kyungmin , Kim Jin Hyoung , Jun Hyoung Oh , Kim Young Hoon , Cho Young-Lai , Yu Young Suk , Min Jeong-Ki , Kim Jeong Hun 
Published: July 2016

Abstract
Retinoblastoma is the most common intraocular malignant tumor in children, affecting approximately 1 in 20,000 live births. In this study, we investigated the role of L1, a transmembrane protein, in proliferation and chemoresistance of retinoblastoma to figure out the potential for the novel therapeutic target. Retinoblastoma tissues demonstrated varying degrees of L1 positivity in 86.6% (26/30) of samples. In particular, the degree of L1 positivity was inversely related with that of Flexner-Wintersteiner rosette formation. Further in vitro studies using stable cell lines which showed up- or down-regulation of L1 demonstrated that L1 was associated with cell-cell adhesion and proliferation of retinoblastoma cells. Retinoblastoma cells with low expression of L1 showed decreased tumor formation in vivo. In addition, L1 expression was related with resistance to carboplatin, one of the most-widely utilized chemotherapeutic agents against retinoblastoma. In line with these results, retinoblastoma cells with higher expression of L1 demonstrated increased resistance to carboplatin in vivo. We also observed diffuse and dense expression of L1 in retinoblastoma tissues from 4 patients who underwent enucleation despite intensive chemotherapy based on carboplatin. Taken together, L1 was related with proliferation and chemoresistance of retinoblastoma and might be a potential therapeutic target of retinoblastoma.
Citation Format: Dong Hyun Jo, Kyungmin Lee, Jin Hyoung Kim, Hyoung Oh Jun, Young Hoon Kim, Young-Lai Cho, Young Suk Yu, Jeong-Ki Min, Jeong Hun Kim. The role of L1 in proliferation and chemoresistance of retinoblastoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2469.
Abstract 2470: Isolation and characterization of cancer stem cells from the human medulloblastoma cell line DAOY: adherent vs. suspension in vitro cell cultures
Authors: de la Rosa Javier , Sáenz Antoñanzas Ander , Fan Xing , Meléndez Bárbara , Rey Juan A. , Castresana Javier S. 
Published: July 2016

Abstract
Brain tumor stem cells (BTSC) in vitro cultures have been made possible by the formation of neurospheres in suspension conditions with the use of serum free medium supplemented with specific growth factors, as B27, EGF, or b-FGF. In this work, we tested a more recent alternative method for the culture of BTSC, using laminin pre-coated flasks and the same medium used for the neurosphere growth, which leads to BTSC expansion attached to a layer.
BTSC cultures in adherence conditions by the use of laminin can afford a more homogeneous exposition to growth factors than sphere cultures do, which promotes a higher enrichment in stem-like cells. Also, it is known that the laminin interactions with integrines or other components of the cell matrix can lead to inhibition signals of cell differentiation. Moreover, the monolayer conditions can support a higher number of cells in the flask.
The medulloblastoma cell line DAOY was cultured in different conditions of normoxia and hypoxia, and several cell populations were obtained for in vitro and molecular experiments.
An increase in the stem features was shown when cells were successively cultured in hypoxia conditions. By contrast, a reduction in these properties was appreciated when cells were exposed to differentiation. In addition, the CD133+ and CD133- subpopulations were isolated from cells grown in laminin pre-coated flasks, and in vitro experiments showed that the CD133+ fraction represented the stem population and it could have BTSC with a higher probability than the CD133- fraction.
The colony formation assay presented similar results for the two cultured methods, but clonogenicity in soft agar was higher in the laminin culture cells. In the cell migration assay, medullospheres migrated similarly to the laminin cultured cells, since both cell populations lost their adherence capacity after being cultured with serum free medium. Gene expression of CD133, CD15 and EZH2 was compared as well, and significant differences were not detected between the two cell populations.
We can conclude that the laminin culture method in adherent conditions and the medullosphere traditional culturing method in suspension are similarly good for obtaining BTSC in DAOY medulloblastoma cell line.
Citation Format: Javier de la Rosa, Ander Sáenz Antoñanzas, Xing Fan, Bárbara Meléndez, Juan A. Rey, Javier S. Castresana. Isolation and characterization of cancer stem cells from the human medulloblastoma cell line DAOY: adherent vs. suspension in vitro cell cultures. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2470.
Abstract 248: Metformin sensitizes endometrial cancer cells to chemotherapy by inhibiting IDH1-TET1 pathway
Authors: Bai Mingzhu , Zhang Zhenbo , Yu Yinhua , Feng Youji 
Published: July 2016

Abstract
Chemotherapy-resistance is the major obstacle for endometrial carcinoma patient administration. Accumulated evidences indicate that metformin sensitizes cancers from several different sites to chemotherapy drugs and reverses progestin resistance in endometrial cancer. Our group has demonstrated that metformin reverses progestin resistance and enhances the rate of cell-killing induced by chemotherapeutic agents in endometrial cancer cells by downregulating GloI expression. Recent study has revealed that aberrant expression of IDH1 contribute to chemotherapy resistance. However, the role of IDH1 in metformin induced chemotherapy sensitivity is not well characterized. As a critical enzyme of the tricarboxylic acid (TCA) cycle, IDH1 catalyzes isocitrate to produce α-ketoglutarate (α-KG), a substrate of TET1, which control TET1-mediated epigenetic modulation of the target genes, including the chemotherapy-resistant genes. In the present study, we have found that IDH1 is overexpressed in endometrial cancers compared with benign endometrial lesions and normal endometria by immunohistochemical analysis of specimens (200 cases of endometrial cancers, 10 cases of benign endometrial lesions and 10 cases of normal endometria). Tissue microarray immunohistochemical detection showed the expression of IDH1, TET1 and 5hmc was positively correlated in different pathological types of endometrial tissue. Interestingly, we found that metformin reduces expression of IDH1 at protein levels with a time- and dose-manners in endometrial cancer cells. Furthermore, overexpression of IDH1 increased TET1 at protein level and blocked metformin-sensitized endometrial cancer to chemotherapy drugs, whereas decrease IDH1 expression lessened TET1 expression and paralleled with the attenuated chemotherapy-resistance. Mechanistic investigations revealed that TET1 involved in metformin-enhanced chemotherapy sensitivity via IDH1 by western blotting and DNA dot blotting assays, this may attribute to that reduced production of α-KG resulted from metformin-suppressing IDH1 is not enough to start TET1-mediated epigenetic modulation of chemotherapy resistant genes. Overall, our findings demonstrate that IDH1 regulates α-KG level and TET1 expression, which in turn affecting metformin mediated endometrial cancer chemotherapeutic sensitivity. Our study suggests IDH1 is a potential target to overcome cisplatin and paclitaxel resistance in endometrial cancer.
Citation Format: Mingzhu Bai, Zhenbo Zhang, Yinhua Yu, Youji Feng. Metformin sensitizes endometrial cancer cells to chemotherapy by inhibiting IDH1-TET1 pathway. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 248.
Abstract 249: Breast cancer cell vesiculation is driven by calpain: implications in cancer therapy
Authors: Taylor Jack , Jaiswal Ritu , Bebawy Mary 
Published: July 2016

Abstract
Microparticles (MPs) are small membrane vesicles (0.1 to 1 μm in diameter) released from the plasma membranes of most cell types, (malignant and non-malignant) upon cellular activation or during apoptosis. We discovered that MPs provide a “non-genetic” mechanism for the acquisition of multidrug resistance and increased metastatic capacity in tumour cell populations, whereby they serve as vectors in the intercellular transfer of functional cancer proteins and nucleic acids. By this mechanism, MPs effectively confer the transfer, dissemination and dominance of within cancer cell populations within a matter of hours.
The aim of this study was to define the pathways governing membrane vesicle biogenesis in malignant and non-malignant cells with the aim of identifying cancer specific mediators, which could serve as novel therapeutic targets in preventing microvesicle induced deleterious traits in cancer.
We preformed a comparative analysis using the non-malignant human brain endothelial cell line (HBEC-D3) cells and drug sensitive and resistant human breast adenocarcinoma cells (MCF-7) and (MCF-7/DX) respectively. Cell surface topography and vesiculation pits were visualized at rest, and in the +/- calcium ionophore, A23187 and the Calpain inhibitor ALLM using contact mode Atomic Force Microscopy (Nanowizard, JPK Instruments, Germany) on fixed cells. We observed that at rest, cells from both malignant cell lines were high vesiculators relative to the HBEC-D3 cells. In the presence of ALLM we observed a direct inhibition of vesiculation in the malignant cells whilst vesiculation was enhanced in the non-malignant cells. Upon the release of calcium from intracellular stores using A23817, we observe an increase in vesiculation across all cell types, however to a greater extent in the HBEC-D3 cells. Interestingly, only upon the release of intracellular calcium in HBEC-D3 cells do we see an inhibition of vesiculation by ALLM. These results clearly demonstrate an alternative pathway governing vesiculation at rest for the non-malignant HBEC-D3 cells. Whereas contrary to this, vesiculation at rest in malignant cells appears to be calpain dependent. Future work aims to validate these findings and examine the presence of distinct pathways of vesiculation in malignant cells relative to non-malignant cells. These results have important implications in defining novel strategies to selectively targeting malignant cells and for the circumvention of deleterious traits acquired through intercellular exchange of extracellular vesicles.
Citation Format: Jack Taylor, Ritu Jaiswal, Mary Bebawy. Breast cancer cell vesiculation is driven by calpain: implications in cancer therapy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 249.