bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 124: Involvement of the notch pathway in the clonogenicity of human multiple myeloma cell lines
Authors: Chiron David , Amiot Martine , Moreaux Jerome , Klein Bernard , Pellat-Deceunynck Catherine 
Published: February 2011

Abstract
Multiple Myeloma (MM) is a fatal plasma cell malignancy characterized by deregulation of both proliferation and cell-death.
Using a collagen based (serum-free) semi-solid assay, we have evaluated the ability of 40 HMCL to form colonies either spontaneously or in the presence of exogenous growth factors (IL6 or IGF-1).
We have shown that 28 Human Myeloma Cell Lines (HMCL) formed colonies in the presence of exogenous IL6, 14 in the presence of exogenous IGF-1 and 12 have the capacity to clone spontaneously without any growth factor.
In the present study, we have addressed:
1) Autocrine growth factors implicated in the spontaneous clonogenicity
2) Gene expression profile (GEP) associated with the spontaneous clonogenicity
On the one hand, we showed that IGF-1 or SCF (CD117) autocrine loop supports the growth of 5 and 1 HMCL, respectively.
On the other hand, GEP analysis of 40 HMCLs revealed that jagged2 gene expression is statistically associated with the spontaneous clonogenicity. Fourteen cell lines express jagged2, among them 11 formed colonies spontaneously.
To confirm this correlation, we next determined JAGGED2 expression by Western-blot and showed that only spontaneous clonogenic HMCL highly expressed this protein.
JAGGED2 is a ligand of NOTCH1 and NOTCH2 receptors that also appear to be highly expressed on MM cells (Western-blot and Flow-cytometry).
Overexpression of JAGGED2 in MM was reported either to be induced by hypomethylation of jagged2 promoter or by a lack of expression of the repressor SMRT/NCoR2. However, these mechanisms are not associated with JAGGED2 expression in our 14 JAGGED2+ HMCLs, suggesting another mechanism(s) currently under investigation.
Of note, jagged2 is expressed by 40% of MM patients (as documented by RT-PCR) and thus is not restricted to HMCL.
To address the involvement of Notch pathway in the spontaneous clonogenicity of myeloma cells, we generated sh-JAGGED2 HMCL using lentiviral systems. We observed that this stable down-regulation fully abrogates spontaneous clonogenic capacity.
To further analyze the implied mechanism(s), we used a low-cellular-density liquid culture (serum-free, cytokine-free) to mimic our collagen-based assay.
In this model, stable down-regulation of JAGGED2 induces inhibition of proliferation followed by delayed cell death. The molecular mechanism implicated in this process is currently under investigation.
Our results highlight a subgroup of JAGGED2 positive HMCLs that display spontaneous clonogenic capability. Furthermore, we described a new implication of JAGGED2/NOTCH pathway in survival and proliferation of myeloma cells under stringent conditions such as collagen-based clonogenic assay.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 124.
Abstract 1242: Expression of steroid receptor coactivators and HER-2/neu in normal and malignant breast tissue in controls and tamoxifen treated tumors
Authors: Moi Line H. , Flaageng Marianne H. , Gandini Sara , Guerrieri-Gonzaga Aliana , Bonanni Bernardo , Lazzeroni Matteo , Gjerde Jennifer , Lien Ernst , Decensi Andrea , Mellgren Gunnar 
Published: February 2011

Abstract
The complex agonist/antagonist effects of tamoxifen may partly be explained by changes in nuclear receptor coactivator expression and activity. In addition, overexpression of the epidermal growth factor receptor HER-2/neu is associated with poor prognosis and tamoxifen resistance in conjunction with coactivator SRC-3/AIB1.
In this study, 64 patients with ER positive breast cancer were randomly treated with 20, 5 or 1 mg tamoxifen/day for 4 week preoperatively. 28 ER positive patients were included as not-treated controls. Specimens at the time of surgery were collected from tumor tissue and normal breast tissue below 1 cm from the tumor. Real-time PCR analyses were performed to measure mRNA expression of the members of the steroid receptor coactivator (SRC) family; SRC-1, SRC-2/TIF-2, SRC-3/AIB1 and the receptor HER-2/neu. The mRNA levels were analyzed with the focus on effects of tamoxifen dose, tissue type, as well as potential correlation to the plasma levels of the biomarkers IGF-I, SHBG and immunohistochemical expression of Ki-67.
The mRNA-levels of SRC-1, SRC-2/TIF-2, SRC-3/AIB1 and HER-2/neu were all significantly higher in tumors compared to normal tissue (P &lt; 0.001). Tamoxifen significantly increased mRNA expression level of the coactivators in a dose-independent manner in both tissue-types, with the clearest effect for SRC-3/AIB1 (P &lt; 0.001). There was no difference in HER-2/neu mRNA levels in tamoxifen treated samples compared to controls. We observed no significant correlation between mRNA levels of the coactivators and HER-2/neu with IGF-1, SHBG or Ki-67.
In conclusion, nuclear receptor coactivators were significantly higher both in breast tumors and normal tissue after tamoxifen treatment; however there was no difference in mRNA levels between the tamoxifen doses of 1, 5 or 20 mg/day. Whether such an increase in expression of coactivators could be a sign of effective endocrine treatment or an attempt of the cells to shift back to a more estrogen sensitive state, remains to be elucidated.
Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1242.
Abstract 1244: RXR agonist induced changes in gene expression in liver and mammary cancers: Confirmation by RT-PCR on independent samples collected years apart
Authors: Cvetkovic Dusica , Clapper Margie , Wang Yang , You Ming , Muccio Donald , Grubbs Clinton , Lubet Ronald 
Published: February 2011

Abstract
Several years ago, our laboratries examined the effects of short-term treatment with the RXR agonist Targretin, a highly effective preventive agent in rodent mammary models, on gene expression. Oligonucleotide microarrays were employed both in normal tissues (liver, lung and mammary gland) and in ER+ mammary cancers (Wang, et al., Molecular Cancer Therapeutics, 2006). It was thought that the gene expression changes observed might serve as potential pharmacodynamic markers, as well as giving mechanistic insights into the efficacy of Targretin. Numerous changes in Targretin treated livers and literally hundreds of changes in Targretin treated mammary cancers were observed by microarray analysis. Pathway alterations in Targretin treated mammary cancers included those for MAPK and TGF-beta signaling. In the present RT-PCR studies, a separate laboratory employed different samples collected approximately four years after the originals. Roughly 20 genes whose expression was modulated in the original liver arrays and a similar number of genes from the original mammary cancer arrays were examined. Of the genes examined in the rat liver, which we expected to be relatively homogeneous, roughly 75% were confirmed by RT-PCR (e.g., cytosolic acyl-CoA thioesterase, CYP 2B2, IGFBP2). More surprisingly, approximately two-thirds of the gene changes observed in the rat mammary cancers (e.g., MMP12, apolipoprotein D, CYP4B1) were confirmed. These results imply that even in different samples collected years apart one can confirm gene expression changes observed in arrays in a relatively homogeneous tissue such as liver. Furthermore, one can confirm gene expression changes observed in mammary cancers, a result potentially more surprising since one might expect substantial heterogeneity in those samples. We are also currently examining expression changes of these same genes following treatment with a series of RXR agonists that are structurally dissimilar to Targretin. Targretin is a cyclic compound, while the analogs have a linear 9-cis-backbone (Muccio et al, Carcinogenesis, 2006). In conclusion, the present data support the use of arrays to identify pharmacodynamic markers that may be utilized with agents of the same class.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1244.
Abstract 1246: Mechanism of endostatin action in prostate cancer in dependent on androgen receptor signaling
Authors: Isayeva Tatyana , Chanda Diptiman , Tsuladze George , Moore Lakisha , Ponnazhagan Selvarangan 
Published: February 2011

Abstract
We recently reported that stable expression of endostatin and angiostatin arrested the progression of well differentiated prostate carcinoma to poorly-differentiated state and distant metastasis in TRAMP mice when given prior to the onset of metastasis switch. Analysis of the expression of angiogenesis-related genes in the prostate tissue of endostatin treated mice indicated a significant downregulation of genes involved in cell motility, proliferation, metastasis and angiogenesis when therapy was initiated at early stage-disease. In vitro experiments demonstrated that recombinant endostatin treatment significantly downregulated the expression of growth factors, receptor tyrosine kinases and proteases in androgen sensitive cells. A similar pattern was confirmed in prostate tissues obtained from in vivo studies. Targeted downregulation of androgen receptor (AR) prior to endostatin treatment indicated that the effect of endostatin through AR downregulation is by a non-genotypic mechanism on MAPK/ERK pathway, and independently of Src kinase. Further analysis indicated the kinetics of endostatin internalization for androgen sensitive prostate cancer cells to be much higher than in androgen independent cells. Co-immunoprecipitation studies in human prostate cancer cells, and yeast two-hybrid studies with endostatin and AR demonstrated a direct binding of endostatin protein with AR. Based on the results so far, we predict that direct interaction of endostatin with AR possibly eliminates ligand binding during early stages of prostate cancer arresting and delaying the progression of the disease. However, once metastatic switch occurs, when the cells grow in androgen independent manner, a limitation in endostatin internalization or binding of non-androgen ligands at other domains in AR impairs the tumoristatic ability of endostatin. Ongoing studies are aimed in identifying interaction domains of endostatin with AR by NMR as well as testing the combination of endostatin therapy with therapies targeting AR signaling.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1246.
Abstract 1249: The role of ATM-dependent Chk2 activation on post-transcriptional gene regulation by RNA-binding protein, HuR: implications for lymphoma development in AT patients
Authors: Mazan-Mamczarz Krystyna , Hagner Patrick , Dai Bojie , Liu Zhenqiu , Gartenhaus Ronald B. 
Published: February 2011

Abstract
Maintenance of genomic stability depends on the DNA damage response a biological tumorigenesis barrier in early stages of cancer development. In response to DNA double strand breaks, ATM phosphorylates multiple proteins involved in both cell cycle checkpoints and DNA repair including the checkpoint kinase Chk2. The human disease ataxia-telangiectasia (AT) in which the ATM gene is deleted or inactivated is characterized by progressive neurodegeneration, immunodeficiency and genomic instability. AT patients show a hypersensitivity to radiotherapy and an extraordinary high risk of developing pediatric lymphomas. Recently it was reported that Chk2 interacts and phosphorylates the RNA-binding protein HuR, leading to alteration of it RNA-binding ability. HuR is a key post-transcriptional regulator of genes involved in stress response, cell cycle, immunoresponse, tumorigenesis, and senescence.
To gain a better understanding of the complexity of the ATM/Chk2/HuR regulatory pathway we investigated the influence of ATM/Chk2 signaling on HuR binding activity in the DNA damage response by global microarray examination of mRNAs associated with HuR in response to ionizing radiation (IR) in both ATM wild type and ATM null lymphocytes. Importantly, pharmacological inhibition either ATM or Chk2 proteins, or knockdown of Chk2 expression using RNA interference, reduced the HuR-mRNA association with a number of validated target genes. Mutation of Chk2 phosphorylated residues in HuR suggests Ser100 site to be important for increased association and Thr118 dissociation of HuR-mRNA complexes after IR.
Our data demonstrated that low dose (1Gy) of IR activates the ATM signaling cascade, but not ATR pathway, resulting in the sequential phosphorylation of Chk2 and HuR, subsequently modulating the association of HuR with target mRNAs and thereby regulating these gene's expression. Functional network analysis revealed signaling pathways, which are frequently deregulated in lymphoid malignancies to be predominantly represented by transcripts differentially associated with HuR after exposure to IR in ATM wild type compared to ATM null lymphocytes. A better understanding of the mechanism and affected species of mRNA could help to develop more effective targeted treatments in ATM null patients.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1249.
Abstract 1253: Combination of chloroquine to inhibitors of the HER family receptors leads to synergistic growth inhibition of breast cancer cell lines
Authors: Shah Apurva N. , Ling Yi-He , Perez-Soler Roman 
Published: February 2011

Abstract
Autophagy is emerging as a new mechanism of cellular escape from different forms of cellular stress including the cytotoxic effects of chemotherapeutic agents. There is preclinical evidence that this mechanism may explain tumor resistance to chemotherapy as well as to biologic agents. In this study, we investigated the effects of the combination of inhibitors of autophagy and inhibitors of the HER family of receptors in breast cancer cell lines. Chloroquine (CQ) is a 4-aminoquinolone with antimalarial, immunosuppressive, and anti-autophagy activity. It raises the intra-lysosomal pH thereby impairing protein degradation and causing accumulation of autophagosomes. Erlotinib (E) is an inhibitor of the EGFR tyrosine kinase and trastuzumab (T) is a monoclonal antibody against the HER2 receptor.
We used the SK-BR-3 cell line (high ErbB1 and ErbB2 expression), and the MCF-7 cell line (low ErbB1 and ErbB2 expression) and studied the effect of T alone, E alone, and in combination with CQ on cell growth inhibition using the MTT assay. Our results indicate that combinations of CQ and T or E for 7 days cause synergistic cell growth inhibition in SK-BR-3 cells (combination index 0.17-0.31) but have no effect on cell growth inhibition in MCF-7 cells.
Flow cytometry analysis revealed that in SK-BR-3 cells exposure to T or E induces G1-phase accumulation and S-phase blockade. However, combinations of T or E with CQ did not further inhibit cell cycle progression. Analysis of apoptosis using the TUNEL reaction assay or by FACS analysis indicated that the combined treatment increases apoptotic cell death associated with increased caspase-3 activity as compared with the treatment with T or E alone, suggesting that activation of apoptotic signal pathways may be involved in the synergistic effect.
Finally, we determined the effect of the combination of CQ and T or E on receptor activation as well as downstream signaling and found that combined treatment enhanced the inhibition of ErbB2 as well as Akt phosphorylation, but had no effect on Erk activation as compared with T or E alone in SK-BR-3 cells.
Conclusion: The combination of CQ with T or E in breast cancer cell lines with high ErbB1 and ErbB2 expression results in synergistic growth inhibition, enhanced apoptosis, and increased inhibition of ErbB signaling via the PI-3K/AKT pathway. This enhanced cytotoxic activity and its potential clinical utility should be explored further. This work was supported in part by NIH grant CA84119 and CA96515.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1253.
Abstract 1262: Bif-1 is required for keeping mitochondrial and lysosomal positive feedback loops in check to prevent apoptosis induced by death receptors in type II cells
Authors: Park Sungman , Komine Kimiyo , Takahashi Yoshinori , Wang Hong-Gang 
Published: February 2011

Abstract
Bif-1, also known as endophilin B1 and SH3GLB1, is involved in the regulation of apoptosis, mitochondrial morphogenesis, and autophagy. We have previously shown that increasing the levels of Bif-1 accelerates Bax conformational change, caspase-3 activation, and apoptotic cell death in response to a variety of intrinsic apoptotic stimuli, whereas the loss of Bif-1 delays all these processes. Here, we report the role of Bif-1 as a negative regulator in the extrinsic pathway of apoptosis by controlling mitochondrial and lysosomal amplification loops in type II cells. There are two different types of cells distinguished by their distinct extrinsic apoptotic signaling pathways. In type I cells, the activation of caspase-8 by death receptor ligation is sufficient to activate downstream effector caspases (e.g. caspaspe-3) for cell killing, whereas in type II cells, caspase cascade amplification through mitochondria and/or lysosome is required. We found that depletion of Bif-1 dramatically enhances not only caspase-3 but also caspase-8 activation and cell death in type II cell lines including MEF, HeLa, and Jurkat, but not in type I H9 cells, following treatment by the extrinsic apoptotic stimuli TNFα/cycloheximide, TRAIL or Fas ligand. Overexpression of Bcl-XL or XIAP in Bif-1 knockout MEFs significantly diminishes the enhanced caspase activation, indicating that a mitochondrial feedback loop is elevated by the loss of Bif-1. Moreover, while treatment with cathepsin inhibitors does not suppress TNFα/cycloheximide-induced caspase-3 activation in Bif-1 knockout MEFs, it completely blocks the activation of caspase-3 in Bif-1 knockout MEFs overexpressing Bcl-XL or XIAP, implying that lysosomal pathway is also involved. Furthermore, inhibition of caspase-8 is able to completely block the activation of caspase-3 induced by TNFα/cycloheximide, indicating that caspase-8 initiates the mitochondrial and lysosomal amplification loops observed in Bif-1 deficient type II cells. Taken together, these studies suggest that Bif-1 plays an important role in the regulation of caspase-8-initiated mitochondrial and lysosomal positive feedback loops for killing type II cells by death receptors.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1262.
Abstract 1265: RbBP6 Isoform 3 (DWNN) is a p53 stabilizer in arsenic trioxide-induced apoptosis in human cancer cell lines
Authors: Dlamini Zodwa , Mbita Zukile , Skepu Amanda , Pugh David , Rees Jasper , Meyer Mervin 
Published: February 2011

Abstract
Domain With No Name (DWNN) has a ubiquitin-like fold and shares 22% similarity with ubiquitin. This suggests its significant importance in cell homeostasis and protein degradation in a human body. The presence of a ubiquitin-like fold suggests a role similar to ubiquitin and RbBP6 may be involved in ubiquitin ligase-like activities. Furthermore RbBP6 interacts with both p53 and pRb which are key components of cell cycle regulation. These two tumour suppressors are key to the understanding the function of the RbBP6. It has been found that upon arsenic trioxide-induced treatment RbBP6 isoform 3 (DWNN) is up-regulated. In this study the role of the DWNN on p53-dependent apoptosis was investigated.
Over-expressions of RbBP6 isoforms was achieved by transfection of recombinant isoforms using Metafectene Easy. Apoptosis was induced using arsenic trioxide and staurosporine. Apoptosis was then measured using APOPercentage and flow cytometry. The expression of RbBP6 gene products and p53 was determined using both real-time PCR and western blotting.
Up-regulation of RbBP6 was observed in As2O3-induced apoptosis in cancer cells. Over-expression of the RbBP6 isoform 1 intensified As2O3-induced apoptosis. MTT assay showed an IC50 of 40µM for As2O3. When this concentration was used to induce apoptosis in human cancer cells and this resulted in induced expression of RbBP6 isoform 1 not the isoform 3. Over-expression of RbBP6 isoform 3 though resulted in stabilization of p53 protein. The apoptosis that was observed was also accompanied by the expression of p53. This study suggests that the DWNN may not be directly involved in the prosecution of apoptosis but may be involved through p53 stabilization. This study suggests that the RbBP6 may be a p53 stabilizer in contrast to mdm2, which is a negative regulator of p53. It will be very important to also determine the relationship between RbBP6 and pRb in both cell cycle and apoptosis
Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1265.