bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 4103: Hepatocellular carcinoma-specific isoforms of methylated DNA-binding protein 2 and their therapeutic and diagnostic potential
Authors: Machnes Ziv M. , Stefanska Barbara , Szyf Moshe
Published: August 2012

Liver cancer is the fifth most common cancer in the world. It is particularly prevalent in developing countries in Asia and Africa. In the US alone, it is estimated that 26,190 adults will be diagnosed with primary liver cancer this year, and 19,590 people will die of the disease. Hepatocellular carcinoma has no efficient cure, has a 5-year survival rate of 14% and is highly metastatic. In the last couple of decades, it has been established that many types of cancer involve major changes in the DNA methylation machinery and in turn, widespread yet highly specific changes in cytosine methylation. DNA methylation is a chemical modification on the DNA associated with gene inactivation, and in contrast to genetic mutation, is dynamic and reversible, making it a preferable target for therapeutics. Methylated-DNA Binding Proteins (MBD) have been shown to play a critical role in the progression and metastasis of cancers in general and specifically in hepatocellular carcinoma. We have identified two isoforms of the MBD2 protein (hcMBD2) that have not been previously reported in any somatic cells: these isoforms are totally silenced in normal liver cells and active in hepatocellular carcinoma. Specific inhibition of these isoforms of MBD2 in hepatocellular carcinoma (HePG2 cell line) has a dramatic effect on cell growth and cellular transformation, but no effect in normal cells, where the isoforms are not expressed. Knockdown experiments show dramatic reduction in cell invasiveness, reduced cell growth rate and increased cell death in HepG2 cells, while primary liver hepatocytes remain largely unaffected. A survey of several types of cancers and their surrounding tissue of origin shows the expression of hcMBD2 in several other types of cancer, such as breast cancer. These results position hcMBD as a promising candidate for cancer diagnostics and therapeutics.

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 4103. doi:1538-7445.AM2012-4103
Abstract 4144: Circulating microRNAs as specific biomarkers for breast cancer
Authors: Park In Hae , Lee Keun Seok , Kang Joo Hyun , Ro Jungsil
Published: August 2012

Background It has been reported that the cancer associated specific microRNAs were detected in blood. The objective of this study was to discover a panel of circulating microRNAs as potential ER+/HER2- breast cancer biomarkers. Methods We compared the levels of circulating microRNAs in blood samples from 11 ER+/HER2- advanced breast cancer patients with age-matched 5 control subjects by using microarray-based expression profiling, which was subsequently validated by real-time quantitative polymerase chain reaction (RT-qPCR). We found that 4 microRNAs (miR-1280, miR-1260, miR-1274b, miR-720) were up-regulated in blood from breast cancer patients (P<0.05, constrained by at least two-fold expression change). We identified the levels of above 4 and additional three microRNAs (miR-21, miR-195, and let-7a) in 40 control subjects, 44 early breast cancer patients (EBC), and 22 metastatic breast cancer patients (MBC). The levels of miR-1280 and miR-1260 in blood were significantly different by the disease status (control<EBC<MBC) (Table 1). The level of let-7a was higher in cancer patients (P<0.001), while there was no difference in the level of let-7a between patients with EBC and those with MBC (P=0.422). Using receiver operational curve (ROC) analysis, blood levels of miR-1280 could detect patients with breast cancer with 85% specificity and 81% sensitivity; while blood let-7a levels could discriminate cancer patients with 90% specificity and 95.2% sensitivity. Conclusions These findings suggest that blood microRNAs are differentially expressed in breast cancer patients, which can be used as potential biomarkers for breast cancer. Table 1. Mean expression levels (SD) of target microRNAs in blood from breast cancer patients compared with blood from healthy controls.

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 4144. doi:1538-7445.AM2012-4144
Abstract 4176: Activated NRAS mediates self-renewal capacity in AML
Authors: Sachs Zohar , Rathe Susan K. , Diaz-Flores Ernesto , Diers Miechaleen D. , Shannon Kevin , Largaespada David A.
Published: August 2012

NRAS mutations are found in 11-14% of AML (Schubbert et al. Nat Rev Cancer 2007, Bowen et al. Blood 2006), implicating NRAS signaling pathways as potential targets for clinical intervention. However, the specific effects of targeting these pathways on AML physiology are currently unclear. We employ a manipulatable murine model of AML to elucidate these phenomena for therapeutic applications. This model harbors a tetracycline repressible, activated NRAS (NRASG12V) transgene along with an Mll/AF9 transgene. Primary leukemia cells are then transplanted into SCID mice and, upon development of clinically evident leukemia, NRASG12V transgene expression is repressed with doxycycline. NRASG12V repression leads to apoptosis and disease remission (Kim et al. Blood 2009). To dissect the critical signaling networks directing remission, immunophenotypic markers, along with the phosphorylation status of critical signaling intermediates, were analyzed by flow cytometry after NRASG12V repression. This analysis revealed that NRAS withdrawal led to an enrichment of less differentiated Mac1/Gr1 negative cells indicating that, in addition to well-described effects on proliferation, NRAS affects leukemia differentiation status. Furthermore, we only found modifications in known NRAS signaling effectors in the less differentiated, Mac1 negative leukemia cells. Therefore, in addition to affecting the differentiation status of the leukemia, oncogene withdrawal leads to cell-type specific signaling alterations. We hypothesize that these signaling alterations mediate remission-induction by altering the self-renewal capacity of the leukemia at the gene expression level. Parallel RNA sequencing and gene expression microarrays were performed to address this hypothesis and revealed that the gene expression pattern of NRASG12V-expressing cells is enriched with hematopoietic self-renewal genes (Krivtsov et al. Nature 2006, Ivanova et al. Science 2002, Gene Set Enrichment Analysis per Subramanian et al. PNAS 2005). Withdrawal of the oncogene led to loss of this self-renewal gene expression program and an enrichment of genes expressed in terminally differentiated, mature cells. Furthermore, the NRASG12V-dependent gene expression program mimics the Mll/AF9-determined, Myb-mediated self-renewal program seen in a similar AML model (Zuber et al. Genes & Dev 2011). These data suggest that the Mll/AF9-mediated self-renewal program requires the continued expression of NRASG12Vand support a novel role for NRASG12V in maintaining the self-renewal capacity AML.

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 4176. doi:1538-7445.AM2012-4176
Abstract 418: Development and characterization of cancer stem cell model from mouse iPS cells
Authors: Chen Ling , Matsuda Shuichi , Kasai Tomonari , Sugii Yuh , Okada Masashi , Igarashi Koichi , Satoh Ayano , Kudoh Takayuki , Kudoh Takayuki , Fu Li , Seno Masaharu
Published: August 2012

The cancer stem cells in capable of continuous proliferation and self-renewal are proposed to play significant roles in oncogenesis, tumor growth, metastasis and cancer recurrence. Cancer stem cells are considered derived from normal stem cells affected by the tumor microenvironment although the mechanism of development is not clear yet. In 2007, Yamanaka's group succeeded in generating Nanog mouse induced pluripotent stem (iPS) cells, in which green fluorescent protein has been inserted into the 5′ untranslated region of the Nanog gene. Usually, iPS cells are considered to be induced into progenitor cells, which differentiate into various normal phenotypes depending on the normal niche. We hypothesized that cancer stem cells could be derived from Nanog mouse iPS cells in the conditioned culture medium of cancer cell lines, which is a mimic of carcinoma microenvironment. As a result, the cells exhibited a high tumorigenicity in vivo with a capacity of self-renewal and the expression of markers associated with stem cell properties and an undifferentiated state. The cells efficiently formed spheroids expressing green fluorescent protein in suspension culture, vasculogenic tubes in MatriGel in vitro and exhibited extensive angiogenesis in vivo, which was confirmed by magnetic resonance imaging and by histochemical analysis. Thus we concluded that a model of cancer stem cells was originally developed using mouse iPS cells and proposed the conditioned culture medium might perform as niche for producing cancer stem cells. It is worthwhile noticing that the mouse iPS cells co-cultured with cancer-derived cells did not form malignant tumors in vivo. This implies that cell-to-cell contact may have inhibitory effect on the conversion of mouse iPS cells into cancer stem cells. Furthermore, demonstration of the genetic alterations and the secreted factors in the tumor microenvironment which convert mouse iPS cells to cancer stem cells, and identification of potentially bona fide markers of cancer stem cells will help the development of novel anti-cancer therapies.

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 418. doi:1538-7445.AM2012-418
Abstract 4183: Overexpression of PTPN2 promotes lung cancer cell proliferation through ERK activation
Authors: Lin Sheng-Yi , Lai Yi-Hua , Wang Chi-Chung , Tsai Meng-Feng , Yu Sung-Liang , Chang Gee-Chen , Chen Jeremy J.W.
Published: August 2012

Lung cancer is the most common cause of cancer deaths in the world, and the incidence is increasing each year. Protein tyrosine phosphatases (PTPs) and their associated signaling pathways are crucial for the regulation of numerous cell functions including growth, motility, mitogenesis and metabolism. PTPN2, also known as TCPTP, is an intracellular protein tyrosine phosphatase, which is ubiquitously expressed. There are two splice variants of TCPTP in human cells, TC45 and TC48, which vary at their C-terminal ends. The TC48 isoform is present in the endoplasmic reticulum and also in the nuclear membrane. However, its role and function on human non-small cell lung cancers remain unknown. In this study, we induced ectopic expression of PTPN2 (TC48) in CL1-0 and H1299 cells to investigate its effect on cell migration, invasion, and colony formation. The interacting proteins of PTPN2 are identified by yeast two-hybrid assay. The results showed that PTPN2 inhibited lung cancer cell proliferation, anchorage-dependent and -independent growth, but not migration and invasion. Yeast two-hybrid assay revealed that PTPN2 interacted with CD74 (major histocompatibility complex class II invariant chain) and PRDX6 (Peroxiredoxin 6) which could promote cell proliferation in previous studies. We also found that overexpression of PTPN2 increased the phosphorylation of ERK. Moreover, activation of ERK was enhanced by co-expression of PTPN2 and CD74 or PRDX6. Taken together, we speculated that PTPN2 might modulate ERK activity through interaction with CD74 and PRDX6 and further promoted lung cancer cell proliferation.

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 4183. doi:1538-7445.AM2012-4183
Abstract 4186: An extensive microRNA-mediated network of RNA-RNA interactions regulates established oncogenic pathways in glioblastoma
Authors: Sumazin Pavel , Califano Andrea , sheng Chiu Hua , Yang Xuerui
Published: August 2012

By analyzing gene expression data in gliobastoma in combination with matched microRNA profiles, we have uncovered a post-transcriptional regulation layer of surprising magnitude, comprising over 248,000 microRNA -mediated interactions. These include ∼7,000 genes whose transcripts act as microRNA ‘sponges’ and 148 genes that act through alternative, non-sponge interactions. Biochemical analyses in cell lines confirmed that this network regulates established drivers of tumor initiation and subtype, including PTEN, PDGFRA, RB1, VEGFA, STAT3, and RUNX1, suggesting that these interactions mediate crosstalk between canonical oncogenic pathways. RNA silencing of 13 microRNA-mediated PTEN regulators, whose locus deletions are predictive of PTEN expression variability, was sufficient to downregulate PTEN in a 3′ UTR-dependent manner and to increase tumor-cell growth rates. Thus, this microRNA -mediated network provides a mechanistic, experimentally validated rationale for the loss of PTEN expression in a large number of glioma samples with an intact PTEN locus.

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 4186. doi:1538-7445.AM2012-4186
Abstract 4189: Excess c-Myc loads tissue-specific enhancers in tumor cells
Authors: Lin Charles , Rahl Peter B. , Loven Jakob , Kagey Michael H. , Burge Christopher B. , Young Richard A.
Published: August 2012

Excessive expression of c-Myc occurs frequently in human cancers, where high levels are associated with tumor aggression and poor clinical outcome. It is well established that the c-Myc protein forms a heterodimer with Max, binds to E-box sequences typically located near the core promoter elements of target genes involved in cellular proliferation, and alters expression of these genes. It is not yet clear, however, how altering the levels of c-Myc affects its activity across the genome to enhance the oncogenic state of cells. We show here that c-Myc occupies occupies enhancer elements only in tumor cells with elevated levels of c-Myc. The enhancers that are occupied are often tumor-specific and associated with the cell-of-origin of the tumor. These and additional results provide insights into a key mechanism by which c-Myc overexpression alters the transcriptional state of cancer cells to enforce their tumorigenic state and malignant potential.

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 4189. doi:1538-7445.AM2012-4189
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

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

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

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

[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

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

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

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

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 (>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 (<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

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

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
Abstract 4389: Impact of regulatory T cell depletion on dendritic cell-tumor fusion vaccine immunotherapy
Authors: Tan Chunrui , Reddy Varun , Ding Enyu , Dannull Jens , Nair Smita , Pruitt Scott K. , Lee Walter T.
Published: August 2012

A promising branch of research in cancer immunotherapy is the development of vaccines comprised of dendritic cells hybridized to tumor cells by electrofusion. Studies in numerous murine models have shown the efficacy of treatment with a dendritic cell-tumor fusion vaccine; however, this is critically dependent on systemic administration of 3rd signals such as IL-12 (Interleukin-12). Translation of these findings into the clinic will be difficult due to toxicity, morbidity, and mortality associated with IL-12 administration. Thus, alternative strategies to enhance the efficacy of fusion vaccines are needed. Regulatory T cells (Tregs) are known to suppress anti-tumor immunity. Treg depletion has been demonstrated to improve tumor immunotherapy in murine tumor models as well as some phase I clinical studies. We therefore investigated whether Treg depletion with the anti-CD25 monoclonal antibody PC61 would significantly improve dendritic cell - tumor fusion immunotherapy in a murine melanoma model. Experiments were conducted using six groups of animals: no treatment (negative control), isotypic monoclonal antibody alone (Y13), Treg depletion alone (PC61), fusion vaccine with Y13 (Fusion + Y13), fusion vaccine with PC61 (Fusion + PC61), and fusion vaccine with IL-12 (Fusion + IL12; positive control). Pulmonary metastases were established through intravenous tail vein injection of 0.25x106 tumor cells (Day 0). Three days later, an injection of 0.6x106 fusion hybrids was delivered intranodally. 250 µg of Y13 or PC61 monoclonal antibodies were delivered one day prior to vaccine delivery. Starting on the day of vaccination in the IL-12 group, 0.2 µg of IL-12 was given daily for 4 days. Three weeks after tumor inoculation, mice were euthanized and the pulmonary metastases were enumerated. The median number of metastases and standard deviation [SD] per group were the following: no treatment= 204 [50]; Y13= 220 [59]; PC61= 211 [49]; fusion+Y13= 126 [67]; fusion + PC61= 72 [74]; fusion + IL12= 1 [11]. Using the Mann-Whitney U test, there was a statistically significant reduction in the number of tumor metastases between both the fusion vaccine + Y13 group and the fusion + PC61 group (P=.0397) as well as PC61 alone group and fusion + PC61 group (P=.002). This suggests that Treg depletion can significantly augment dendritic cell-tumor cell fusion melanoma immunotherapy. Our results support the development of novel therapeutic modalities that include Treg depletion, or modulation, to enhance the efficacy of dendritic cell - tumor fusion cancer immunotherapy.

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 4389. doi:1538-7445.AM2012-4389
Abstract 4404: Microparticle generation and activation after treatment with paclitaxel and bavituximab combination therapy in metastatic breast cancer
Authors: Marron Marilyn T. , Chalasani Pavani , Camacho Daniel , Iannone Maria , Schmidt Kathy , Stopeck Alison
Published: August 2012

Background: Breast cancer is the leading cause of life-threatening malignancy affecting women and the second leading cause of female cancer death in the United States. Weekly paclitaxel, alone or in combination with other chemotherapies, has proven to be an effective and well-tolerated therapy for patients with metastatic disease. Due to the tumor's dependence on vascularization for progression, survival and dissemination, targeting a tumor's vascular network is an important additional cancer management strategy. Bavituximab, a monoclonal antibody developed by Peregrine Pharmaceuticals against phosphatidylserine (PS), is a vascular disrupting agent designed to selectively attack tumor blood vessels already in existence. Under normal conditions, PS is localized to the internal surface of the plasma membrane. However, PS is preferentially localized on the outer surface of vascular endothelial cells in tumors, possibly due to stress conditions in the tumor microenvironment. Bavituximab is able to localize and bind specifically to PS in tumor vessels in a α2-glycoprotein 1 dependent manner, mediating the binding of host effector cells to the tumor vascular endothelium. This leads to vessel damage, vascularity reduction, necrosis, and growth retardation within the tumor. Microparticles are vesicles that are released from cells after activation, stress, death, or malignant transformation. Elevated levels of microparticles derived from platelets, endothelial cells, and/or leukocytes have been associated with several disease states, including cancer, however, the effect of anti-angiogenic or vascular disrupting agents on microparticle production is unclear. We investigated microparticle formation in our patients at baseline, in response to Paclitaxel chemotherapy, and after addition of Bavituximab. Patients and Methods: We initiated a phase I clinical trial in patients with Her-2 negative metastatic breast cancer treated with paclitaxel (80 mg/m2)on a weekly schedule for 3 out of 4 weeks, and weekly bavituximab (3 mg/kg) for 4 out of 4 weeks. Each cycle was defined as 4 weeks of therapy. Microparticles were isolated from peripheral blood and examined by flow cytometric phenotyping. Leukocyte, endothelial cell, and activated platelet microparticles were quantified and longitudinal trends analyzed. Five patients have been enrolled to date with additional patients accruing. At presentation, the longitudinal trends in microparticle formation from platelets, endothelial cells, and leukocytes will be presented in response to weekly Paclitaxel versus combined Paclitaxel and Bavituximab therapy.

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 4404. doi:1538-7445.AM2012-4404
Abstract 4488: Inflammation-related biomarkers and risk of epithelial ovarian cancer
Authors: Poole Elizabeth M. , Lee I M. , Buring Julie E. , Hankinson Susan E. , Tworoger Shelley S.
Published: August 2012

Introduction: Chronic inflammation caused by ovulation-related wound healing is theorized to cause ovarian carcinogenesis. We examined associations between three plasma biomarkers of inflammation, CRP, IL-6, and TNFαR-2, and risk of epithelial ovarian cancer in a nested case-control study of ovarian cancer cases and controls from the Nurses’ Health Study (NHS) and NHSII as well as in the Women's Health Study (WHS) cohort (CRP only). We further performed a meta-analysis with previously published studies of these biomarkers and ovarian cancer. Methods: Associations between quartiles of CRP, IL-6, and TNFαR-2 and risk of epithelial ovarian cancer were calculated using unconditional logistic regression (NHS/NHSII) or Cox proportional hazards regression (WHS); NHS/NHSII and WHS were combined using random effects meta-analysis. All analyses were adjusted for age, menopausal status/post-menopausal hormone use, duration of oral contraceptive use, tubal ligation, parity, and body mass index. The NHS/NHSII analyses were additionally adjusted for blood draw characteristics (fasting status, time of day and month of draw). Random effects meta-analysis was used to combine these results with previously published results. Results: In the NHS/NHSII (n=218 cases) and WHS (n=159 cases), a 59% increased ovarian cancer risk was observed in the 4th quartile of CRP compared to the 1st quartile (95% CI: 1.08-2.34). Further, CRP >10mg/L compared to <1 mg/L, was associated with a 2.21-fold increased ovarian cancer risk (95% CI: 1.29-3.80). In meta-analyses with previously published studies, the 3rd compared to the 1st tertile of CRP was associated with a 41% increased risk (95% CI: 1.14-1.74) (Table). There were no statistically significant associations between quartiles of IL-6 or TNFαR2 and ovarian cancer risk in the NHS/NHSII or in a meta-analysis with a previous publication. Conclusion: Our results suggest that higher levels of circulating CRP, but not IL-6 or TNFαR2, are associated with increased risk of ovarian 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 4488. doi:1538-7445.AM2012-4488