bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 4205: Identification of glycine N-methyltransferase-regulated genes in prostate cancer cells
Authors: Ottaviani Silvia , Brown Ciara O'Hanlon , Waxman Jonathan , Ali Simak , Buluwela Laki 
Published: August 2012

Abstract
Glycine N-methyltransferase (GNMT) is a S-adenosylmethionine (SAM)-dependent methyltransferase which catalyses the transfer of the methyl group on SAM to the amino acid glycine to generate N-methyl glycine (sarcosine), a compound with poorly defined biological functions. In prostate cancer GNMT may act as a tumour-susceptible gene. Its expression has been shown to be abundant in normal prostate and benign prostatic hyperplasia tissues and diminished in prostate cancer. It is therefore important to determine the significance of GNMT in the development and progression of prostate cancer and investigate the gene expression changes upon the loss of its expression in prostate cancer cells. Using gene expression microarray analysis of the androgen-responsive LNCaP cell line, we previously identified genes that were differentially expressed upon treatment with the synthetic androgen R1881 (Ngan et al 2009 Oncogene 128: 2051-2063). GNMT was the third most significant up-regulated gene, showing up-regulation by 19-fold after 24 hours of R1881 treatment. Using a panel of prostate cancer cell lines, GNMT expression was seen to be highest in androgen receptor (AR) positive cells, where expression was increased after treatment with R1881 and reduced following addition of the anti-androgen bicalutamide. Together, these findings highlight the importance of GNMT in the androgen-mediated regulation of prostate cancer. In the present study, we aimed to gain new insight into the specific function of GNMT in prostate cancer. We used siRNAs to investigate the effects of GNMT knockdown on global gene expression. The expression profiling was carried out in the LNCaP cell line using the Illumina HT-12 v4 array platform. To minimize off-target effects, LNCaP cells were treated with two different siRNAs targeting the GNMT transcript and a non-targeting siRNA was used as control. Differentially expressed genes that were statistically significant in both siRNA-mediated GNMT knockdown were validated by TaqMan Real-Time RT-PCR and considered for further analysis. In addition, to provide a detailed and comprehensive assessment of the androgen response in LNCaP cells, the LNCaP transcriptome was also analysed after AR knockdown compared to non-targeting siRNA control and R1881 treatment compared to no ligand control. To our knowledge, this is the first study that reveals potential GNMT downstream targets in prostate cancer cells. Further analysis will better characterize the molecular pathways triggered by the enzyme in the progression of the cancer.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4205. doi:1538-7445.AM2012-4205
Abstract 4208: Post-translational modification of E2F1 in malignant melanoma
Authors: Meng Peng , Ghosh Rita 
Published: August 2012

Abstract
Malignant melanoma has the highest fatality among all skin cancers. No current treatment significantly enhances survival once metastasis is established. Previous studies have shown that E2F1, a transcription factor, is over-expressed in melanoma cells. However, the mechanism through which E2F1 is elevated remains unknown. E2F1 is known to be involved in many important biological processes, including cell cycle progression, DNA damage, DNA repair, differentiation, development, autophagy and apoptosis. This underscores the importance of E2F1 in carcinogenesis. Normally in late S phase, E2F1 is recognized by the E3 ligase p45 SKP2 and undergoes ubiquitination and finally degradation in 26S proteasome. Our overall hypothesis is that E2F1 escapes proteasomal degradation in melanoma cells due to changes in post-translational modification. In this study we have used melanoma cells of increasing disease progression. Our results show that although the primary melanoma cells have high level of E2F1 message and protein, it is unstable. On the other hand the more metastatic melanoma cells have low levels of E2F1 which is however very stable. Consistent with this result, post-translational modification of E2F1 including the phosphorylation at Serine 337 and the acetylation at Lysine 117 increase with melanoma progression, which suggests that these post-translational modification sites might play an important role in stabilization of E2F1 and keep it functionally active in the more metastatic cell lines. E2F1 knockdown data also shows that E2F1 KD can inhibit cell proliferation in early stage melanoma cells but not in the more metastatic cells, which also suggest that inhibition of post-translational modifications and stability of E2F1 may be a more effective way to inhibit melanoma progression to more advanced stages. Abrogation of acetylation is expected to cause E2F1 protein instability. On the other hand, if acetylation is potentiated, the stabilized E2F1 will continue to promote progression through the cell cycle. We are currently testing whether the ectopic expression of the continuously acetylated E2F1 protein can rescue proliferation inhibition caused by E2F1 down-regulation, and drive metastasis and a mutant E2F1 with abrogated acetylation can block rescue of the proliferation inhibition in the E2F1 down-regulated melanoma cells.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4208. doi:1538-7445.AM2012-4208
Abstract 4220: Beta-catenin signaling initiates the activation of astrocytes and contributes to the pathogenesis of astrocytomas
Authors: Yang Chunzhang , Iyer Rajiv , Ikejiri Barbara , Lonser Russell , Zhuang Zhengping 
Published: August 2012

Abstract
Astrocytes are the most abundant cell in the central nervous system (CNS). Following injury to the nervous system, astrocytes respond through a repair process known as astrocyte activation. While the molecular mechanisms of astrocyte activation are not completely established, understanding the dynamic changes that occur in response to injury could help identify critical signaling pathways involved in the pathogenesis of brain tumors. To determine the mechanisms underlying astrocyte activation, including the initiating events and regulatory mediators of this process, we analyzed the molecular signaling changes after scratch injury of astrocytes. We discovered that the interruption and destabilization of cadherin-catenin complexes plays a critical role in the initiation and regulation of astrocyte activation. We further found that similar expression changes and signaling pathways are also featured in gliomas, but were found to exist in a dysregulated manner. Inhibition of β-catenin signaling was also found to diminish both the astrocyte response to injury and the malignant phenotype of gliomas. These findings provide a unique mechanism of normal astrocyte activation and shed light on the pathogenic mechanism of glioma, which may help to develop the diagnostic and therapeutic targets for gliomas.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4220. doi:1538-7445.AM2012-4220
Abstract 4229: The characterization of drug-tolerant cancer cell populations by Colony Lysate Array (CoLA)
Authors: Kume Kohei , Nishizuka Satoshi S. , Ikeda Miyuki , Miura Sawako , Maesawa Chihaya , Wakabayashi Go 
Published: August 2012

Abstract
[Background] Increasing evidences indicate that heterogeneity within cancer cell population plays a critical role in response to cytotoxic stresses including drug treatment. We characterized human cancer cell populations that formed colonies in the presence of anticancer drugs at cellular and molecular levels. [Materials and Methods] For colony formation, human cancer cells (HCT-116, HeLa, HT-29, MCF-7, and MKN-45) were sparsely disseminated (10 cells/cm2) in the presence of anticancer drugs (cisplatin, docetaxcell, gefitinib, and sorafenib). To characterize the drug-tolerant individual colonies, we established colony lysate array (CoLA), a tool used for the protein expression analysis of a single-colony, using modified “reverse-phase” protein lysate microarrays (RPAs). [Results] For in vitro modeling of cancer relapse after curative treatment, we consistently observed cell populations that form colonies under 0.1- 10 μM drug concentrations. Interestingly, the 50% colony-inhibition concentration was consistently more than 10-fold higher than that of growth-inhibition for cell-based assays. CoLA assay allows one to use a lysate from a single colony for hierarchical clustering by a panel of cancer stem cell (CSC) markers. Unlike FACS analysis, CoLA is advantageous in detection of full fractions of proteins including those in the nucleus. Thus far, we have found that MKN-45 colonies in the presence of cisplatin expressed CD44, a putative CSC marker in a concentration-dependent manner. Pre-treatment of actinomycin D (AMD), an RNA synthesis inhibitor strongly suppressed MKN-45 colony formation in the presence of cisplatin; however cycloheximide, a protein synthesis inhibitor did not affect the colony formation. [Discussion] Differences in drug concentrations between the colony-inhibition and the growth-inhibition indicate that colony formation and simple cell growth are functionally different. The CD44 expression in MKN-45 colonies in the presence of cisplatin may suggest that these colonies emerged in the presence of drugs acquired a “CSC-like” phenotype. The suppression of colony formation by AMD may also suggest that the colonies require de novo RNA synthesis for the gain of drug resistant phenotype. [Conclusion] The drug-tolerant cell populations exhibit a CSC-like phenotype and require de novo RNA synthesis for the gain of drug resistant phenotype, possibly involved in the heterogeneity of cancer cell population.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4229. doi:1538-7445.AM2012-4229
Abstract 423: SENP1 regulates OCT4 under hypoxia: effect of its sumoylation on protein stability and drug susceptibility of human pluripotent germ cell tumors
Authors: Huang Yen-Hua , Wu Yu-Chih , Ling Thai-Yen , Shen Chia-Ning 
Published: August 2012

Abstract
Well-differentiated testicular germ cell tumors (TGCTs) are more drug insensitive and have a poorer prognosis than pluripotent germ cell tumors. However, the mechanism underlying the differentiation regulation of pluripotent seminomas/embryonal carcinomas (ECs) still remains largely unknown. Herein, we demonstrated an important role of SUMO1/sentrin specific peptidase 1 (SENP1) in the sumoylation and stability of the OCT4 protein in the drug sensitivity of hypoxic ECs. Hypoxia decreased the OCT4 protein level, but not the messenger RNA level, in pluripotent ECs. Hypoxic challenge and SUMO1 overexpression increased OCT4 sumoylation and protein instability. A further mutation at the specific OCT4 lysine 123 (HA-OCT4-K123R) effectively suppressed OCT4 sumoylation and protein instability, demonstrating the important role of the specific sumoylation of lysine 123 in OCT4 protein stability under hypoxia. Consistently, overexpression of SUMO1 decreased the endogenous OCT4 half-life in hypoxic NCCIT cells. The band-shift of endogenous sumoylated OCT4 in hypoxic NCCIT cells was demonstrated using Western blot analysis. SENP1 effectively suppressed OCT4 sumoylation and increased OCT4 stability and drug sensitivity in hypoxic NCCIT cells in vitro. Furthermore, overexpression of SENP1 in hypoxic NCCIT cells increased the drug sensitivity in a nude mice model, demonstrating the upstream regulation of SENP1 in OCT4 sumoylation, protein stability, and the drug susceptibility of NCCIT cells. In summary, we demonstrated that the sumoylation regulator, SENP1, positively regulates OCT4 stability and drug sensitivity of pluripotent EC cells through sumoylation. Findings of this study provide insights into the regulation by sumoylation of pluripotent TGCTs differentiation, which has the potential for pharmacological development of effective therapeutic targeting.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 423. doi:1538-7445.AM2012-423
Abstract 4233A: The opposite effects of doxorubicin on bone marrow cells versus cancer cells in vivo depend on glucosylceramide synthase
Authors: Bhinge Kaustubh N. , Gupta Vineet , Meyer Sharon , Blaylock Benny , Zhang Qian-Jin , Liu Yong Yu 
Published: August 2012

Abstract
Bone marrow suppression and tumor drug resistance are adverse effects observed in patients with chemotherapy severely limit cancer treatments. It is unclear by which cellular mechanism anticancer drugs suppress bone marrow while drug-resistant tumor survives. We report that due to the difference in the glucosylceramide synthase (GCS) that catalyzes ceramide glycosylation determining ceramide-induced apoptosis or glycosphingolipid mediated maintenance of stem cells, doxorubicin can eliminate bone marrow stem cells and expand cancer stem cells. Doxorubicin treatments significantly decreased the number of bone marrow stem cells (BMSCs, ABCG2+) and sphere formation in dose-dependent fashion (1-5 mg/kg). In tumor-bearing mice, doxorubicin treatments (6 days) significantly decreased bone marrow stem cells and peripheral blood cells at 2 mg/kg and 5 mg/kg. In contrast, doxorubicin increased the number of breast cancer stem cells (BCSCs, CD24-/CD44+/ESA+) more than 3 times at 5 mg/kg treatment. Furthermore, silencing GCS with MBO-asGCS prevented BCSC number increase. Similarly, therapeutic-dose of doxorubicin (1 mg/kg/week, i.p., for 42-days), decreased bone marrow stem cells and increased breast cancer stem cells. Breast cancer cells, but not bone marrow cells, highly expressed glucosylceramide synthase (GCS) which was associated with pluripotency of stem cells. These results indicate that doxorubicin may have the opposite effects, suppressing BMSC versus expanding BCSC in vivo, and GCS is a determinant for the differentiated responsiveness between bone marrow cells, and breast cancer cells.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4233A. doi:1538-7445.AM2012-4233A
Abstract 424: Amplification of OCT4-pseudogene POU5F1B is a poor prognostic factor in gastric cancer
Authors: Hayashi Hidetoshi , Arao Tokuzo , Matsumoto Kazuko , Nagai Tomoyuki , Kimura Hideharu , De Velasco Marco A. , Fujita Yoshihiko , Yamada Yasuhide , Okamoto Isamu , Nakagawa Kazuhiko , Nishio Kazuto 
Published: August 2012

Abstract
POU5F1B is a processed pseudogene and highly homologous to OCT4, which is crucial in the regulation of pluripotency during embryonic development of embryonic stem cell. Since recent reports have demonstrated that POU5F1B mRNA is expressed in several types of cancer tissue, their oncogenic role remains unclear. Here we further investigated that the biological function of POU5F1B. We found that POU5F1B, which is located side by side with MYC gene on 8q24, was frequently involved in MYC amplicons in gastric cancer. Gene copy number analysis revealed that POU5F1B and MYC genes were highly amplified in several gastric cancer cell lines. In addition, the POU5F1B mRNA expression levels were certainly upregulated using PCR and sequencing analysis. Then, we hypothesized that gene amplification of POU5F1B mediates some biological roles in cancer cells. We introduced POU5F1B gene into SNU-16 or TU-KATO III gastric cancer cell lines and established stable cell lines SNU-16/GFP, /POU5F1B, TU-KATOIII/GFP and /POU5F1B. Overexpression of POU5F1B clearly decreased cellular proliferation and inhibited colony forming ability. Interestingly, we found that the increased gene copy number of POU5F1B is a significant poor prognostic factor in 180 cases of gastric cancer. We are now under investigation for its oncogenic properties, gene expression changes by microarray analysis and chemoresistance using these stable POU5F1B transfectants.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 424. doi:1538-7445.AM2012-424
Abstract 4242: A humanized tumor mouse model to characterize the interaction of human disseminated cancer cells with the human immune system
Authors: Werner-Klein Melanie 
Published: August 2012

Abstract
Most primary cancers can be surgically removed, but many patients will die from metastatic disease months to years after initial therapy. Adjuvant therapies are increasingly tailored to exploit characteristics of the primary tumor however they usually improve the survival of less than 10% of breast cancer patients. It has been recently shown that dissemination is an early event and that disseminated cancer cells (DCC) differ genetically from the primary tumor. Therefore a model is needed which i) provides a human, autologous immune system and ii) allows the expansion of DCC, which belong to the rarest cells in the human body (1-2 cells per 106 bone marrow cells in positive patients), in order to investigate the interaction of these particular cell populations. Here we show that a humanized tumor mouse model can be established using hematopoietic stem cells (HSC) and DCC isolated from diagnostic BM-aspirates of melanoma and mammary carcinoma patients. Bone marrow samples are obtained prior to tumor resection. HSC are purified and engrafted by intra-femoral injection into NOD-scidIL2Rg-/- (NSG) mice and show long-term reconstitution (&gt;24 weeks) of lymphoid and myeloid lineages, also upon serial transplantation. DCC enriched from diagnostic BM-aspirates or lymph node samples can be transplanted and are able to establish tumors in NSG mice, even at low cell numbers (&lt;10 cells) in 50 to 70% of DCC-containing samples. Since human melanoma and mammary carcinomas are, in later stages, characterized by wide-spread metastasis, involving bone, lung and liver, we currently focus on whether and how the humanized immune system enables the systemic cancer spread of DCC derived tumors.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4242. doi:1538-7445.AM2012-4242
Abstract 4369: The macrophage migration inhibitory factor (MIF) contributes to tumor growth and metastasis though interaction with the host immune response
Authors: Simpson Kendra D. , Templeton Dennis J. , Cross Janet V. 
Published: August 2012

Abstract
The Macrophage Migration Inhibitory Factor (MIF) is overexpressed in many cancers and the degree of expression correlates with tumor aggressiveness. MIF contains a conserved tautomerase activity for which a physiological substrate or function has yet to be identified. We determined that sulforaphane (SFN), a chemopreventive agent prevalent in broccoli, covalently modifies MIF and inhibits its enzymatic tautomerase activity with an IC50 within the concentration range observed in the plasma of human subjects following a broccoli sprout meal. We are examining the role of MIF in tumor growth and metastasis in the 4T1 model of breast carcinoma. This model recapitulates many aspects of human breast tumor progression, including spontaneous metastasis from the mammary fat pad to similar target organs in similar proportions. We found that a 4T1 tumor cell line depleted of MIF forms smaller tumors than the 4T1 cells that express, and is reduced in its ability to metastasize to the lung. Reconstitution of the MIF deficient 4T1 cells with wild-type MIF rescues the defect in tumor growth and metastasis, while a tautomerase-deficient MIF does not. This suggests a function for the tautomerase activity in tumor progression and metastasis. Importantly, the MIF dependent growth differences are only manifested in vivo, as the MIF KD cell line is not compromised in growth or colony formation in vitro, suggesting that MIF may be contributing to the interaction between the tumor and the host immune response. This was confirmed by our demonstration that MIF deficient and MIF containing tumors exhibited similar growth properties in immunodeficient animals. This may represent an alternative mechanism for chemoprevention in which SFN can target the tumor microenvironment rather than the tumor cells. We are currently working to characterize a leukocyte population whose recruitment is altered in MIF depleted tumors.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4369. doi:1538-7445.AM2012-4369
Abstract 4384: Targeting of 4-1BB by monoclonal antibody, PF-05082566, enhances T cell function and promotes antitumor activity
Authors: Fisher Timothy S. , Kamperschroer Cris , Oliphant Theodore , Love Victoria A. , Lira Paul D. , Doyonnas Regis , Bergqvist Simon , Baxi Sangita , Rohner Allison , Shen Amy C. , Huang Chunli , Sokolowski Sharon , Sharp Leslie L. 
Published: August 2012

Abstract
4-1BB (CD137, TNFRSF9) is a costimulatory receptor expressed in an activation induced manner on several subsets of immune cells. Numerous studies of mouse and human T cells indicate that 4-1BB promotes enhanced cellular proliferation, survival, and cytokine production. 4-1BB agonist mAbs have demonstrated efficacy in prophylactic and therapeutic settings in both monotherapy and combination therapy tumor models and have established durable anti-tumor protective T cell memory responses. PF-05082566 is a fully human IgG2 which binds to the extracellular domain of human 4-1BB with high affinity and specificity. In preclinical studies this agonist antibody demonstrated its ability to activate NF-κB and induce downstream cytokine production, promote leukocyte proliferation, and inhibit tumor growth in a human PBMC xenograft tumor model. The mechanism of action and robust anti-tumor efficacy of PF-05082566 support its clinical development for the treatment of a broad spectrum of human malignancies.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4384. doi:1538-7445.AM2012-4384