bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2182: Epigenetic regulation and growth suppression by NDN, an imprinted tumor suppressor gene whose expression is decreased in epithelial ovarian cancers
Authors: Yang Hailing , Das Partha M. , Lu Zhen , Yu Yinhua , Marquez Rebecca T. , Liao Warren , Bast Robert C.
Published: August 2012

NDN is a monoallelically expressed, maternally imprinted gene located on chromosome 15q11.2. Deletion and uniparental disomy of the NDN gene is causally associated with the Prader-Willi syndrome, a congenital neuro-developmental disorder. Studies of brain development suggest that NDN functions as a suppressor of neuronal growth. Recent studies have shown that NDN gene expression is downregulated in melanoma and urothelial cancers, indicating that it may also act as a tumor suppressor gene. We have now found that NDN gene expression is also downregulated in 50% of 14 ovarian tumors and 9 out of 10 ovarian cancer cell lines. Hypermethylation of 2 CpG sites in NDN promoter was detected in 5 out of 10 cell lines by pyrosequencing, and 5-aza-2′-deoxycytidine treatment revived NDN expression at different levels, suggesting that DNA hypermethylation is one of the mechanisms of NDN downregulation. Re-expression of the NDN gene product Necdin in SKOv3 ovarian cancer cells significantly inhibited growth by clonogenic assays associated with upregulation of caspase-3 activity. Expression of Necdin did not induce autophagy. As SKOv3 cells are p53 null, the mechanism(s) by which Necdin induces cell death is independent of p53 activity. Our observations that Necdin expression is downregulated in majority of ovarian cancers and cancer cell lines and that re-expression of Necdin inhibited cancer cell growth support the notion that NDN is a tumor suppressor gene.

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 2182. doi:1538-7445.AM2012-2182
Abstract 22: Differential IGF-II response of AA and CA normal breast cell lines to prolactin treatment
Authors: Calderon Teleka , León Marino De , De León Daisy D.
Published: August 2012

African-American (AA) breast cancer patients have lower survival compared with Caucasian-American (CA) patients. This survival disparity is significant in view of the lower incidence of breast cancer among AA. Lower incidence of breast cancer is associated with parity and lactation in young women. Lactation's protective effect is mediated by fatty-acid binding protein 3 (FABP3), a protein that promotes differentiation of breast epithelial cells. We have demonstrated that AA normal women below 50 years have lower FABP3 levels as compared to CA women (p = 0.030). FABP3 is a protective tumor suppressor that increases during pregnancy and lactation, in response to the lactation hormone prolactin (PRL). PRL effects on the breast are mediated by IGF-II. Thus, we propose that PRL treatment of normal epithelial breast cell lines would increase IGF-II to promote differentiation, increase FABP3, and decrease FABP5. FABP5 is associated with metastasis and may compensate for FABP3 decrease. We treated MCF10A (CA) and AG11132 (AA) normal breast epithelial cell lines with recombinant human PRL (0-200 ng/ml) for 24 hours. Cell lysates were examined for protein and mRNA levels of IGF-II, FABP3, and FABP5. In MCF10A cells, PRL stimulated an increase in protein levels of IGF-II (p=0.044), and a decrease in protein levels of FABP5 (p=0.044). Protein levels of FABP3 significantly decreased with increasing PRL concentration (p=0.030). IGF-II mRNA levels also increased at 50 and 200 ng/ml PRL (2.59 and 2.58 fold, respectively). In AG11132 cells, protein levels of FABP3 significantly increased with increasing PRL concentration (p=0.016). IGF-II and FABP5 mRNA levels increased significantly at 10 ng/ml PRL (49.91 and 2.13 fold, respectively); however, no corresponding changes were seen in protein levels. Though both cell lines respond to PRL treatment, only the MCF10A line displays increased IGF-II and decreased FABP5, which are protective changes in normal mammary cells. FABP3 levels decreased in MCF10A cells at higher PRL concentrations; this may be due to untreated MCF10A cells expressing significantly more FABP3 and prolactin, relative to AG11132 cells. The higher levels of PRL and FABP3 in untreated MCF10A cells indicate that they are more differentiated and thus require less PRL stimulation, relative to the AG11132 cells, to achieve a differentiated state. The dissimilar responsiveness of these cell lines to PRL may suggest decreased protection against breast carcinogenesis in AA patients, and may help us to further understand this health disparity.

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 22. doi:1538-7445.AM2012-22
Abstract 2214: COUP-TFII suppresses NFκB activation in endocrine-resistant breast cancer cells
Authors: Litchfield Lacey M. , Klinge Carolyn M.
Published: August 2012

COUP-TFII is an orphan nuclear receptor that can function as either a transcriptional activator or repressor. We have previously shown that COUP-TFII expression is reduced in tamoxifen-resistant LCC9 breast cancer cells and that overexpression of COUP-TFII restored the ability of tamoxifen to inhibit cell proliferation. An increase in NFκB activity and p65/RELA level has been reported in endocrine-resistant breast cancer cells. Because NFκB activation results in increased expression of anti-apoptotic and pro-proliferative genes, increased NFκB signaling promotes the survival of cancer cells. The goal of the current study was to further elucidate the mechanism by which COUP-TFII enables cells to maintain endocrine sensitivity and to determine if COUP-TFII modulates NFκB activity in tamoxifen-resistance. To examine whether COUP-TFII can suppress NFκB activity, MCF-7 (tamoxifen-sensitive, TAM-S) and LCC9 (tamoxifen-resistant, TAM-R) breast cancer cells were transfected with a NFκB luciferase reporter and treated with TNFα to activate NFκB. Cotransfection with COUP-TFII reduced NFκB activity in both TAM-S and TAM-R cell lines. Knockdown of COUP-TFII with siRNA led to an increase in p65 expression; conversely, COUP-TFII overexpression led to a suppression of p65 expression. COUP-TFII overexpression also reduced TNFα-induced endogenous NFκB target gene expression. Preliminary data also suggests that suppression of NFκB activation by COUP-TFII leads to a reduction in cell viability in MCF-7 and LCC9 cells in response to tamoxifen and TNFα treatment. This indicates a novel role for COUP-TFII in suppression of NFκB activity which may explain the ability of COUP-TFII to promote tamoxifen-sensitivity. COUP-TFII may be both a useful biomarker to predict tamoxifen-sensitivity as well as a target to restore endocrine sensitivity to resistant 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 2214. doi:1538-7445.AM2012-2214
Abstract 2223: Epigenetic silencing of ribosomal RNA genes by Mybbp1a
Authors: Liu Hsuan , Tan Bertrand , Yung Benjamin Y.-M.
Published: August 2012

Transcription of the ribosomal RNA gene repeats by Pol I occurs in the nucleolus and is a fundamental step in ribosome biogenesis and protein translation. Due to tight coordination between ribosome biogenesis and cell proliferation, transcription of rRNA and stable maintenance of rDNA clusters are thought to be under intricate control by intercalated mechanisms, particularly at the epigenetic level. Here we identify the nucleolar protein Myb-binding protein 1a (Mybbp1a) as a novel negative regulator of rRNA expression. Suppression of rDNA transcription by Mybbp1a was linked to promoter regulation as illustrated by its binding to the chromatin around the hypermethylated, inactive rDNA gene promoters. Our data further showed that downregulation of Mybbp1a abrogated the local DNA methylation levels and histone marks associated with gene silencing, and altered the promoter occupancy of various factors such UBF and HDACs, consequently leading to elevated rRNA expression. Mechanistically, we propose that Mybbp1a maintains rDNA repeats in a silenced state while in association with the negative epigenetic modifiers HDAC1/2. Results from our present work reveal a previously unrecognized co-repressor role of Mybbp1a in rRNA expression. They are further consistent with the scenario that Mybbp1a is an integral constituent of the rDNA epigenetic regulation that underlies the balanced state of rDNA clusters.

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 2223. doi:1538-7445.AM2012-2223
Abstract 223: Oncogenic resistance of Akt kinases to dephosphorylation through an ATP-dependent molecular switch
Authors: Chan Tung
Published: August 2012

The serine/threonine Akt protein kinases (Akt1, Akt2 and Akt3) affect multiple cellular functions associated with “hallmark” properties of cancer, such as cell growth and survival, differentiation, metabolism and migration. Hyperphosphorylation of a threonine residue (Thr308 in Akt1) in the activation loop of Akt kinases is a prerequisite for the deregulated Akt activity frequently that is observed in neoplasia. Conversely, phosphatases including type 2A serine/threonine phosphatase (PP2A), reverse Akt phosphorlyation and activity. Here, we describe a new layer of control of Akt phosphorylation that points to ATP binding pocket occupancy as a means to decelerate Akt dephosphorylation. We show that targeting Akt kinases to the cell membrane markedly reduces the ability of phosphatases to dephosphorylate Thr308. This effect depends on the occupancy of the ATP binding pocket by either ATP or ATP competitive Akt kinase inhibitors (A443654 or G690693). To reconstitute this effect, we use purified phosphatases and Akt proteins to show that ATP markedly inhibits the dephosphorylation of phospho-Thr308 in vitro. Mutational analysis reveals that Arg273 in Akt1 and the corresponding Arg274 in Akt2 are essential for shielding Thr308 against dephosphorylation. While the binding of ATP and several ATP “mimic” inhibitors, ATP-γS, A-443654 and G690693 inhibits Akt dephosphorylation, the binding of other closely related molecules, ADP, ADPβS and isoquinoline sulphonamide (IQS, Ki 0.23uM) does not block dephosphorylation, suggesting unique determinants in the γ-phosphate of ATP that regulate Akt dephosphorylation. These results suggest that occupancy of the ATP-binding pocket of Akt kinases stabilizes a conformational state of the Akt kinase domain that restricts phosphatase access to phospho-Thr308, thereby sustaining Akt phosphorylation. Finally, we determine that phosphorylated Akt kinases in untransformed cells are subject to rapid dephosphorylation. However, in several cancer-derived cell lines, phosphorylated Akt kinases are highly resistant to dephosphorylation and the resistance depends on ATP-occupation. In addition, dephosphorylation resistance provides a mechanistic explanation for the ‘paradoxical’ phosphorylation of Akt previously described for ATP competitive inhibitors, A443654 and G690693. Also, dephosphorylation resistance may be the converging point of the oncogenic signals that induce Akt hyperactivation. Exploration of structures and amino acids involved in this process may hold the key to developing the next generation of pharmacological agents that could promote normal Akt physiology while inhibiting cancer cells for more positive results in cancer 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 223. doi:1538-7445.AM2012-223
Abstract 2233: IKBKE activates Akt independent of phosphatidylinositol 3-kinase/PDK1/mTORC2 to sustain malignant transformation
Authors: Guo Jianping , Coppola Domenico , Cheng Jin Q.
Published: August 2012

Serine/threonine kinase Akt regulates key cellular processes such as cell growth, proliferation, and survival. Activation of Akt by mitogenic factor depends on phosphatidylinositol 3-kinase (PI3K). Here, we report that IKBKE activates Akt in response to inflammatory agent but not growth factor stimuli through a PI3K-independent pathway. Depletion of IKBKE inhibits basal and inflammatory factor-stimulated Akt activation. IKBKE directly phosphorylates Akt-Thr308 and -Ser473 independent of plecstrin-homology (PH) domain. IKBKE activation of Akt was not affected by inhibition of PI3K, knockdown of PDK1 or mTORC2 complex. Further, this activation could be inhibited by Akt inhibitors MK-2206 and GSK690693 but not the compounds (perifosine and triciribine) targeting PH domain of Akt. Expression of IKBKE largely correlates with activation of Akt in breast cancer. Moreover, inhibition of Akt suppresses IKBKE oncogenic transformation. These findings indicate that IKBKE is an Akt-Thr308 and -Ser473 kinase and directly activates Akt independent of PI3K, PDK1 and mTORC2. Our data also suggest that Akt inhibitors targeting the PH domain have no effect on the tumours in which hyperactive Akt is resulted from elevated IKBKE.

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 2233. doi:1538-7445.AM2012-2233
Abstract 2237: Analysis of the PI3K/Akt signaling pathway in neuroblastoma shows stage dependent expression of PI3K isoforms
Authors: Fransson Susanne M. , Abel Frida , Eriksson Helena , Kogner Per , Martinsson Tommy , Ejeskär Katarina
Published: August 2012

The phosphoinositide-3 kinase (PI3K) pathway plays a critical role in cancer cell growth and survival and has also been implicated in the development of the childhood cancer neuroblastoma. In neuroblastoma high mRNA expression of the PI3K catalytic isoform PIK3CD is associated to favorable disease. Yet, activation of Akt is associated with poor prognosis. Since the contribution of the numerous members of this pathway to neuroblastoma pathogenesis is mainly unknown, genes of the PI3K/Akt pathway were analyzed at mRNA and/or protein level. Out of 88 studied genes, five (PRKCZ, PRKCB1, EIF4EBP1, PIK3RI and PIK3CD) showed lower mRNA expression and one (PDGFRA) showed higher expression in aggressive compared to favorable tumors. PIK3R1 encodes p85α, the regulatory subunit of the Type IA PI3K and is suggested to have tumor suppressing functions and in neuroblastoma, high expression of PIK3R1 is strongly correlated to overall patient survival. p110α, encoded by PIK3CD was preferentially expressed in favorable neuroblastomas while p110α (encoded by PIK3CA) was mainly found in patients with advanced disease which also showed higher levels of both p-Akt T308 and p-Akt S473. Further more, levels of p-Akt T308 showed inverse correlation to Pten levels although no significant difference in protein levels of Pten could be detected comparing aggressive and favorable neuroblastoma tumors. The pattern of p110alpha and p110delta indicates complementary functions in Akt activation depending on neuroblastoma stage and evaluation of the expression of the different PI3K isoforms in each neuroblastoma patient could be crucial for the success of treatment with PI3K isoform specific inhibitors.

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 2237. doi:1538-7445.AM2012-2237
Abstract 224: TOPK phosphorylation of MKP1 prevents solar ultraviolet irradiation-induced inflammation by inhibiting p38 signaling
Authors: Li Shengqing , Zhu Feng , Zykova Tatyana , Kim Myoung Ok , Bode Ann M. , Peng Cong , Ma Weiya , Dong Zigang
Published: August 2012

Solar ultraviolet (UV) irradiation is a major environmental factor that causes DNA damage, inflammation, and skin cancer. T-LAK cell-originated protein kinase (TOPK) is widely expressed in both normal and cancer cells and functions to inhibit apoptosis and promote carcinogenesis. However, its function in inflammation is not known. The p38 MAPK signaling pathway plays an important role in solar UV light-induced inflammation. The phosphorylation level of p38 was reported to be up-regulated after transfection of the TOPK gene into COS-7 cells. We found that the phosphorylation level of p38α was increased in TOPK-/- mouse embryonic fibroblasts (MEFs) compared with TOPK+/+ MEFs after stimulation with solar UV light. Our observations unveil a novel role for TOPK. We found that TOPK negatively regulated the activity of p38α by phosphorylating the p38α-specific phosphatase MKP1 and enhancing the stability of MPK1. Notably, the absence of TOPK in mice resulted in a striking increase in skin inflammation. Therefore, we conclude that TOPK has a protective function in solar UV light-induced inflammation.

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 224. doi:1538-7445.AM2012-224
Abstract 2247: Torin2 targets mTOR activity and induces apoptosis in DLBCL cells
Authors: Uddin Shahab , Bu Rong , Thangavel Saravanan , Hussain Azhar R. , Al-Kuraya Khawla S.
Published: August 2012

The mammalian target of rapamycin (mTOR), a serine/threonine protein kinase, acts as a master switch for cellular anabolic and catabolic processes, regulating the rate of cell growth and proliferation. Dysregulation of the mTOR signaling has been found in many human cancers, including epithelial ovarian cancer, breast cancer, prostate cancer and lung cancer. mTOR has been shown to activate the PI3-kinase/AKT survival pathway and understanding the interplay among signaling molecules in the PI3K/Akt/mTOR pathway is of utmost importance. Two distinct mTOR complexes; mTORC1 and mTORC2, have been identified. mTORC1 is downstream of Akt, sensitive to rapamycin inhibition, and controls cap-dependent protein translation. In contrast, mTORC2 is directly upstream of Akt and is resistant to rapamycin. In order to successfully inhibit mTOR activity, mTORC1 and 2 have to be simultaneously inhibited at the same time to effectively induce apoptosis. The role of mTOR in diffuse large B-cell lymphoma (DLBCL) has not been fully elucidated. Therefore, we examined the effect of a new generation mTOR inhibitor (Torin2) on a panel of DLBCL cell lines. We found that Torin2 treatment inhibited cell viability and induced apoptosis in DLBCL cell lines in a dose dependent manner with an IC50 of 53nM. In addition, Torin2 also activated the mitochondrial apoptotic pathway by causing changes in the mitochondrial membrane potential, activation of caspase-9 and -3 and cleavage of PARP. Finally, Torin2 treatment of DLBCL cell lines also down-regulated the expression of inhibitor of apoptosis proteins (IAPs); XIAP and Survivin in a dose dependent manner. As mTOR has been shown to activate down stream targets such as p70S6 as well as up-stream targets such AKT, we will further investigate the effect of Torin2 treatment on these targets. In addition, we will also determine whether Torin2 treatment causes disruption of cross talk between mTOR and PI3-kinase/AKT pathways. These studies will give us an insight on the molecular relationship between these survival pathways and may detect newer survival molecules that can be targeted for efficient treatment of these cancers.

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 2247. doi:1538-7445.AM2012-2247
Abstract 2254: FIP200 regulation by hypoxia in brain endothelial cells
Authors: Kar Niladri S. , Tipps Russell , Yang Haifeng , Gladson Candece L.
Published: August 2012

Angiogenesis is a prominent characteristic of glioblastoma tumors. Hypoxia occurs in glioblastoma tumors and is thought to promote angiogenesis largely through a HIF-dependent mechanism. The effect of hypoxia on survival proteins expressed by endothelial cells (ECs), such as focal adhesion kinase interacting protein of 200kDa (FIP200, also known as RB1CC1), has received little attention. We recently reported that the expression of FIP200 is increased in the angiogenic endothelial cells of glioblastoma tumors. FIP200 can promote cell survival through its promotion of autophagy, or by inhibiting Pyk2 activation and Pyk2-mediated apoptosis. We found that hypoxia upregulated FIP200 protein expression and that this upregulation of FIP200 was independent of the downregulation of ARNT, suggesting it was HIF-independent. We then examined the post-translational modification of FIP200 and whether it was differentially regulated in hypoxia. We found that FIP200 is degraded in the proteosome in normoxia, and that there may be alterations in the proteosomal degradation pathway in hypoxia that contribute, in part, to the elevated FIP200 protein level. Understanding the mechanism for the increased expression of FIP200 in hypoxia may provide future therapeutic targets for new anti-angiogenic 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 2254. doi:1538-7445.AM2012-2254
Abstract 2258: Cadmium induces autophagy through ROS-dependent activation of the LKB1-AMPK signaling in skin epidermal cells
Authors: Son Youngok , Shi Xianglin
Published: August 2012

Cadmium is a toxic heavy metal which is environmentally and occupationally relevant. The mechanisms underlying cadmium-induced autophagy are not yet completely understood. The present study shows that cadmium induces autophagy, as demonstrated by the increase of LC3-II formation and the GFP-LC3 puncta cells. The induction of autophagosomes was directly visualized by electron microscopy in cadmium-exposed skin epidermal cells. Blockage of LKB1 or AMPK by siRNA transfection suppressed cadmium-induced autophagy. Cadmium-induced autophagy was inhibited in dominant-negative AMPK-transfected cells, whereas it was accelerated in cells transfected with the constitutively active form of AMPK. mTOR signaling, a negative regulator of autophagy, was downregulated in cadmium-exposed cells. In addition, cadmium generated reactive oxygen species (ROS) at relatively low levels, and caused poly(ADP-ribose) polymerase-1 (PARP) activation and ATP depletion. Inhibition of PARP by pharmacological inhibitors or its siRNA transfection suppressed ATP reduction and autophagy in cadmium-exposed cells. Furthermore, cadmium-induced autophagy signaling was attenuated by either exogenous addition of catalase and superoxide dismutase, or by overexpression of these enzymes. Consequently, these results suggest that cadmium-mediated ROS generation causes PARP activation and energy depletion, and eventually induces autophagy through the activation of LKB1-AMPK signaling and the down-regulation of mTOR in skin epidermal 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 2258. doi:1538-7445.AM2012-2258
Abstract 2277: Autophagy-associated necroptosis contributes to cancer cell cytotoxicity induced by the chalcone compound SBC2
Authors: He Weiyang , Wang Qiong , Srinivasan Balasubramanian , Xu Xiuling , Chen Wenshu , Padilla Mabel T. , Gou Xin , Xing Chengguo , Lin Yong
Published: August 2012

Chalcone-based compounds are potential agents for cancer chemoprevention and chemotherapy. The recently developed chalcone-based compound SBC2 suppresses xenograft tumor growth in nude mice, however, the mechanisms by which SBC2 kills cancer cells are elusive. In this study, we have investigated the cellular signaling pathways involved in SBC2's cytotoxicity in cancer cells derived from lung and bladder tumors. SBC2 potently killed different cancer cells, which was effectively blocked by the necroptosis inhibitor Necrostatin-1 and knockdown of the necroptosis pathway components RIP1 and RIP3, suggesting that SBC2-induced cytotoxicity is associated with necroptosis. SBC2 robustly activated JNK and ERK through activation of their upstream activating kinases MEKK1 and MKK7. Blocking JNK and ERK effectively blocked SBC2-induced cytotoxicity, implying an important role of these MAPKs in SBC2-induced cancer cell death. In addition, SBC2 strongly induced autophagy, which was suppressed when JNK was blocked. Furthermore, SBC2 triggered BCL-XL phosphorylation that was dependent on JNK. Importantly, suppression of autophagy with either pharmacological inhibitors or a siRNA targeting the essential autophagy component ATG7 effectively attenuated SBC2-induced cell death. These results suggest that SBC2 kills cancer cells through activating JNK-mediated and autophagy-associated necroptosis. Taken together, our observations substantiate SBC2 as a potential anticancer therapeutic and identify a novel pathway for cancer cell killing by SBC2 that involves autophagy and necroptosis.

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 2277. doi:1538-7445.AM2012-2277
Abstract 2295: miR-342 modulates ID4 expression in breast cancer
Authors: Crippa Elisabetta , Lusa Lara , Fiorino Antonio , Marchesi Edoardo , Cecco Loris De , Pierotti Marco A. , Gariboldi Manuela
Published: August 2012

Integration of the results from a transcriptome profiling of coding and non coding RNAs (miRNA) on familial (BRCA1- or BRCA2-mutated, or BRCAX) and sporadic breast cancers identified possible miRNA-dependent mechanisms associated with the different BRCA groups analyzed. Among the miRNA/target gene pairs found, we focused on that composed by miR-342 and ID4 gene. ID4 is a negative regulator of B-HLH transcription factors frequently expressed in cancer and miR-342 is deregulated in many cancers, including breast. All of our groups had relatively high expression of miR-342 and low expression of ID4, except for one subgroup of BRCAX cases (named BRCAXa, comprising cases with clinical characteristics similar to BRCA1) that had reciprocal expression patterns of this pair. We evaluated the expression levels of the putative pair in different breast cancer cell lines and found that ID4 gene expression was on average higher in estrogen receptor negative (ER-) cells; on the contrary, miR-342 had higher expression in estrogen receptor positive (ER+) cells. The direct binding of miR-342 to the 3′ UTR of ID4 and its potential inhibitory effect was functionally validated using a reporter luciferase system. Reciprocal expression of miR-342 and ID4 was then confirmed in vitro in the triple negative MDA-MB-231 cell line, that, similarly to the BRCAXa subgroup, had low expression of miR-342 and where miR-342 introduction reduced ID4 protein levels. ID4 is a negative regulator of BRCA1 and modulation of its expression in breast cancer is inversely related with that of BRCA1. Being ID4 a target of miR-342, we hypothesized a relationship between these two genes and the miRNA and that low levels of miR-342 could provide a mechanism for increasing ID4 that negatively regulates BRCA1 expression. Analysis of their levels in our cases supported this thesis. In the BRCAXa class lower levels of miR-342 were associated with reduced expression of BRCA1. We hypothesized that down-regulation of ID4 through miR-342 could provide a mechanism for increasing BRCA1 expression. We tested this hypothesis in the MDA-MB-231 cells, where we found miR-342 mediated downregulation of ID4, but no increase in the expression of BRCA1 at either gene or protein levels. These results showed that ID4 is a validated target of miR342 and propose a role of miR-342 in familial breast cancer where it could impair expression of ID4. Targets of ID4 different than BRCA1 can be altered in the BRCAXa subgroup.

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 2295. doi:1538-7445.AM2012-2295
Abstract 2309: Down-regulation of miR-181b contributes to the poor prognosis of adverse cytogenetically abnormal acute myeloid leukemia by targeting PBX3
Authors: Li Zejuan , Huang Hao , Li Yuanyuan , Jiang Xi , Chen Ping , Arnovitz Stephen , He Chunjiang , Zhang Zhiyu , Neilly Mary Beth , Price Colles , Zhang Yanming , Larson Richard , Beau Michelle Le , Rowley Janet , Chen Jianjun
Published: August 2012

Altered expression of microRNAs (miRNAs, a class of small regulatory RNAs) is associated with various types of cancers, including acute myeloid leukemia (AML). In our previous bead-based miRNA expression profiling assay, we observed that miR-181a, b, c, and d were all expressed at a higher level in the favorable prognosis subtypes of cytogenetically abnormal AML (CA-AML) carrying t(8;21), inv(16), or t(15;17) than in an intermediate- to poor-risk subtype of CA-AML harboring MLL rearrangements. Indeed, we found that increased expression of miR-181a or miR-181b was significantly (P<0.05) associated with longer OS in univariable testing, whereas only that of miR-181b remained significant (P<0.05) upon multivariable testing, after adjusting for other clinical, cytogenetic, and molecular variables. Through correlating expression of miR-181b with those of miR-181 putative target genes in 35 CA-AML patient samples, we identified 159 genes that exhibited a significantly inverse (P<0.05; Pearson Correlation) correlation of expression with miR-181b. PBX3 has the most significant inverse correlation with the expression of miR-181b, so we chose PBX3 as an important candidate target of miR-181 for further studies. We conducted luciferase reporter and mutagenesis assays and showed that PBX3 is a direct target of miR-181a/b. We also showed that forced expression of miR-181a/b significantly down-regulated endogenous expression of PBX3 in MLL-rearranged leukemic cells at both the RNA and protein levels. Ectopic expression of miR-181b significantly (P<.05) promoted apoptosis and decreased viability of MONOMAC-6/t(9;11), THP-1/t(9;11), and KOCL-48/t(4;11), and delayed leukemogenesis in MLL-fusion-mediated mouse leukemia model; such effects could be reversed by forced expression of PBX3 coding region. Our data suggest that the silencing of miR-181b and thereby the activation of the target genes, such as PBX3, likely contributes to the poor prognosis of adverse CA-AML patients. Thus, restoring expression of miR-181b and/or targeting the PBX3 pathways in poor prognosis AML patients may provide new strategies to improve outcome substantially.

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 2309. doi:1538-7445.AM2012-2309
Abstract 2328: Targeting angiogenesis: Anti-docking site peptides to Met receptor and nanotechnology
Authors: Cantelmo Anna Rita , Sogno Ilaria , Noonan Douglas M. , Focaccetti Chiara , Principi Elisa , Albini Adriana
Published: August 2012

The Met tyrosine kinase receptor is involved in different cell responses during development and pathological conditions. In cancer, Met can promote growth, invasion, angiogenesis and tumor metastasis following the interaction with its ligand, the hepatocyte growth factor (HGF). We decided to develop angiogenesis inhibitors that target the HGF pathway, impairing tumour neo-vascularization and metastatic spreading. We investigated the anti-angiogenic proprieties of a synthetic peptide mimicking the intracellular Met-tail, which was delivered into cells by fusion with the internalization sequences from Antennapedia or HIV-Tat. We are also trying to do peptide delivery by using carbon nanotubes. In order to evaluate the effect of Met-derived inhibitors on angiogenesis, we treated HUVEC with peptides and we evaluated their ability to interfere with HGF-induced proliferation, migration and morphogenesis of endothelial cells in vitro and angiogenesis. Kaposi's sarcoma (KS), the most frequent neoplasia in patients with AIDS, which originates from endothelial origin and is highly vascularized, shows features compatible with the biological properties of HGF. We used KS as tumour model to test the effect of peptides on tumour growth in vivo. We found that the peptides inhibited ligand-dependent endothelial cell proliferation, migration and morphogenesis in vitro and interfered with HGF-dependent downstream signalling. In vivo, the peptides inhibited HGF-induced angiogenesis and Kaposi's sarcoma tumour growth. We also demonstrated that diacylglycerol kinases (DGK) contribute to the malignant phenotype of KS. The data obtained show that the peptides impair angiogenesis triggered by HGF, suggesting the use of anti-docking site compounds as therapeutic agents to interfere with the angiogenesis process. The development of angiogenesis inhibitors and the identification of new intracellular transducers effective in the high vascularised KS cells, open the possibility of a combination therapy that concomitantly interferes with tumour neo-vascularization and the malignant properties of KS.

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 2328. doi:1538-7445.AM2012-2328
Abstract 2333: Serotonin: A known neurotransmitter functions as an angiokine to support cancer progression
Authors: Zamani Ali , Roy Anshu , Zhai Ling , Maxuitenko Yulia , Li Rongbao , Qu Zhican
Published: August 2012

Platelet aggregation leads to significant serotonin release from its major storage and results in increasing of serotonin levels at injury site and thrombotic tumor environment. Many studies have shown that platelet activation plays a crucial role in tumor progression; however, the role of serotonin in angiogenesis and tumor progression has not been well studied. In this study, we have tested the hypothesis that 5-HT promotes angiogenesis, and antagonizing 5-HT activity has anti-angiogenic benefit in controlling tumor growth. Real time PCR and western blot studies showed that endothelial cell expressed 5-HT receptor 1B (HTR1B) in higher level than other 5-HT receptors. Endothelial cell proliferation and tube formation were significantly affected by blocking HTR1B and the cAMP and IP1 assays have revealed the HTR1B as the inhibitory type of GPCR. Stimulation of endothelial cell with 5-HT or HTR1B agonist has led to activation of two individual signaling pathways: ERK and Akt / mTOR. In further studies, p70S6K was recognized as the merging point of these signaling. These kinases have been also activated by known angiogenic factors (VEGF and FGF) but the mechanism of activation was different from serotonin and it was through their tyrosine kinase receptors. In contrast, pretreatment of endothelial cell with a selective HTR1B antagonist have led to blockade of the 5-HT induced kinases’ activation. We also demonstrated angiogenic promoting activity of 5-HT with a mouse Matrigel plug (in vivo angiogenesis model system) and antiangiogenic potential of antagonists against HTR1B with an ex vivo tumor angiogenesis model (xenograft CAM assay) and xenograft mice model of human ovary cancer (SKOV-3). Selective HTR1B antagonist displayed the synergistic effect (combination index analysis) in blocking tumor-induced new blood vessel formation when it was applied in combination with Sutent (VEGFR2 antagonist). HTR1B antagonist also showed preclinical efficacy in the xenograft model of human ovary cancer by reducing over 50% in tumor size and blood vessel density marker.The results of this study enhanced our understanding of the serotonin-signaling pathway in human endothelial cells during angiogenesis. This research also revealed the potential of 5-HT signaling as the new target for antiangiogenic development.

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 2333. doi:1538-7445.AM2012-2333
Abstract 2342: Identification of oncogenes and tumor suppressor genes using immortalized lung bronchial epithelial cells and small airway epithelial cells
Authors: Gao Boning , Huang Chunxian , Girard Luc , Gazdar Adi F. , Shay Jerry W. , Minna John D.
Published: August 2012

We have immortalized human normal proximal bronchial epithelial cells (HBECs) for the study of lung tumors arising in the central compartment of the lung, and now have over 30 of these strains (growing in defined KSFM media) including many isogenic derivatives with various oncogenic changes (Can Res 2004, Can Res 2006). We have extended this by immortalizing normal distal (small airway) epithelial cells that serve as models for the study of tumors arising in the peripheral compartment of the lung. Using Cdk4 and hTERT exogenous expression vectors (as used for HBECs) and serum free defined media, we have immortalized (N= 19) human small airway epithelial cells (HSAECs) from peripheral lung. We have characterized the HBECs and HSAECs and found they have the property of lung basal /stem cells. In the current study, we compared the genome-wide RNA expression profile of HBECs/ HSAECs with 108 lung tumor cell lines and identified a panel of genes that are differentially expressed in these two cell types. We found ∼ 1200 genes that are 2 fold over expressed in tumor cells lines compared with HBECs/HSAECs (p ≤ 0.005). Many known lung tumor oncogenes such as members in cancer/testis (CT) antigen families (XAGE/GAGE/MAGE), proliferation-promoting E2F2 transcription factors, and Kinesin family are over-expressed in tumor lines validating the comparison strategies. In addition, we found genes that had been shown to be involved in other types of tumors but had not been reported in lung tumors. Importantly, we found several genes that had not been implicated as oncogenes previously, thus these are potential novel oncogenes for lung tumor transformation. We also found ∼1300 genes that are 2 fold over expressed in HBECs/HSAECs compared with tumor cell lines (p≤ 0.006). Many of the genes are lung basal cell markers (Keratin and Laminin family members) or known tumor suppressor genes (p53 binding genes and metallothionein genes) as expected. Like in the case of tumor specific genes, we found several genes that had not been reported functioning in the inhibition of tumor transformation. Thus, these are candidate tumor suppressor genes. The current study showed that the immortalized HBEC and HSAECs are ideal models for the discovery of novel oncogenes and tumor suppressor genes.

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 2342. doi:1538-7445.AM2012-2342
Abstract 2353: Therapeutic effect of cilengitide in combination with CKD-602, a campothecin derivative, against experimental glioblastoma
Authors: Kim Young-Hoon , Park Judy , Lee Jin Kyung , Kim Bokyong , Choi Seung Ah , Phi Ji Hoon , Park Chul-Kee , Kim Seung-Ki , Kim Chae-Yong
Published: August 2012

The prognosis and the clinical course for glioblastoma patients remain dismal in spite of various multidisciplinary approaches of treatment, such as concurrent chemoradiotherapy with temozolomide. Especially, the resistance to temozolomide of primary or recurrent glioblastoma is the significant obstacle to the cure of this tumor. In the present study, we evaluated the in vitro and in vivo antitumor effect of cilengitide in combination with CKD-602, a camptothecin derivate, for experimental glioblastoma. The combination treatment with cilengitide and CKD-602 enhanced the cytotoxic effects to the glioblastoma cell lines, including U87MG and U251MG and increased the proportion of apoptosis of the tumor cells, compared with the monotherapy with either drug. Nude mice with established U87MG glioblastoma were assigned to the 4 groups; control group (injection with saline only), 2 cilengitide group (injection with a dose of cilengitide at 2 mg/mL), CKD-602 group (injection with a dose of CKD-602 at 2 mg/mL), and combination group. In animals with combination therapy, the significant reduction of tumor volume was demonstrated (p < 0.05). The immunohistochemistry with CD31 and Annexin-V showed that this synergistic effect was caused by the decrease of angiogenesis by cilengitide and the increase of apoptosis by CKD-602. Cilengitide in combination with CKD-602 could be an alternative treatment option for glioblastoma. Keywords; glioblastoma; cilengitide; CKD-602; angiogenesis; apoptosis

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 2353. doi:1538-7445.AM2012-2353
Abstract 2354: A neural origin for intracranial germ cell tumors
Authors: Tan Chris
Published: August 2012

Intracranial germ cell tumours (GCTs) are thought to arise from germ cells that aberrantly migrate to the brain during embryogenesis. In normal development, germ cells migrate from the hindgut towards the gonads. GCTs are found in several regions outside of the gonads and all of these are all thought to be midline structures. Therefore, the observation that GCTs occur in midline structures, and that normal germ cells migrate along the midline forms the basis of the current hypothesis for their formation. All GCTs regardless of location also share similar histology. Intracranial GCTs often occur in the ventral midline, such as the pineal and suprasellar regions. However, we challenge this model. We suggest that intracranial GCTs arise from endogenous neural progenitors in the brain rather than from misplaced germ cell progenitors. Neural stem cells have the potential to become pluripotent when Oct4 is activated. When these cells are transplanted into SCID mice they form teratomas, a type of GCT. We postulate that if only one gene is required to trigger formation of a GCT from a brain cell, that it is reasonable to suggest this as a more likely mechanism for GCT development. Oct4 is expressed in the brain until E13.5, so a delay in Oct4 silencing may allow pluripotent cells to form these tumours. Using doxycycline-dependent Oct4-expressing transgenic mice, we have shown that expression of Oct4 allows neural tissue to form teratomas. We have also surveyed the current literature which reveals that many GCTs also occur in all regions of the brain.

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 2354. doi:1538-7445.AM2012-2354
Abstract 2368: Unbiased quantitative assessment of Her-2 expression of circulating tumor cells in patients with metastatic and non metastatic breast cancer
Authors: Pierga Jean-Yves , Ligthart Sjoerd T. , Bidard François-Clement , Decraene Charles , Bachelot Thomas , Delaloge Suzette , Brain Etienne , Campone Mario , Viens Patrice , Terstappen Leon WMM
Published: August 2012

Circulating tumor cells (CTC) can provide the basis for a real-time liquid biopsy and may guide the use of targeted therapies. We report on unbiased quantification of Her-2 protein expression of CTC. Her-2 assessment of CTC was performed using the CellSearch® system in 103 metastatic (M1) and 88 non metastatic (M0) breast-cancer patients. Digital images of Cytokeratin-PE, DAPI, CD45-APC, and Her-2-FITC from these samples were stored. Expression of Her-2 on CTC was determined by manual review and an automated algorithm using Her-2-FITC fluorescence of leukocytes to determine the Her-2-expression threshold in each sample. Her-2 expression of CTC varied greatly within and between patients compared to Her-2 expression of leukocytes. In M1 patients, a threshold of 75% of Her-2 positive CTC in patients with >5 CTC showed a relatively low discrepancy rate between the primary tumor and CTC Her-2 status. Applying this threshold, 9% of M1 patients with Her-2 negative primary tumors had Her-2 positive CTC status and 29% of M1 patients with Her-2 positive primary tumors had Her-2 negative CTC status. No Her-2 discrepancy was observed between CTC and primary tumor in M0 patients. Our findings demonstrate the feasibility of real-time quantitative and reproducible assessment of treatment targets on CTC, opening a path towards personalized treatment. Her-2 expression is heterogeneous among CTC within each patient. Overall, M1 patients with Her-2 positive primary tumors exhibited Her-2 negative CTC frequently, whereas discrepancies in Her-2 status were limited in other clinical settings.

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 2368. doi:1538-7445.AM2012-2368