bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3086: α-arrestin-1 acts as a nuclear transcriptional regulator of endothelin A receptor signalling to promote ovarian cancer progression
Authors: Rosanò Laura , Cianfrocca Roberta , Tocci Piera , Spinella Francesca , Castro Valeriana Di , Salvati Erica , Biroccio Anna Maria , Natali Pier Giorgio , Bagnato Anna
Published: August 2012

In epithelial ovarian cancer (EOC), endothelin (ET)-1/endothelin A receptor (ETAR) autocrine loop activates epithelial to mesenchymal transition (EMT) and malignant progression through the activation of β-catenin-driven transcriptional programs. Although it has been demonstrated that α-arrestin-1 (α-arr1) is involved in ETAR signalling acting as cytoplasmic scaffold protein, the specific contribution to ETAR-regulated EOC progression in the nuclear compartment remains undefined. In this study, we demonstrated that in response to ETAR activation by ET-1, endogenous as well as exogenous α-arr1 translocated to the nucleus in different EOC cell lines. To study a putative role of α-arr1 in controlling gene expression, we investigated the relationship of α-arr1 with β-catenin. We found that ET-1-driven α-arr1 nuclear translocation is associated with a nuclear translocation of with β-catenin and their physical interaction, as shown by microscopy and biochemical analysis. This nuclear complex, that include TCF4 transcription factor, is localized in ET-1-dependent manner on the promoter regions of specific β-catenin target genes, such as ET-1, matrix-metalloproteinase-2, and Cyclin D1, thus promoting their transcription. Gain/loss of function approaches as well as nuclear mutant α-arr1 expression demonstrated that this complex is critical for the recruitment and binding of p300 acetyltransferase on these promoters, resulting in enhanced H3 and H4 histone acetylation, enhanced promoter activity and gene expression, specifically required for ETAR-induced cell migration, invasion, and EMT. In a murine orthotopic model of metastatic human EOC, silencing of α-arr1 or expression of nuclear mutant α-arr1, as well as ETAR blockade, by the specific antagonist zibotentan, inhibits metastasis and intravasation. Finely, in human EOC tissues, α-arr1/β-catenin nuclear complexes are selectively enriched at specific gene promoters compared to non-tumoral ovarian tissues. Therefore, our study provides insights into how a nuclear α-arr1-mediated epigenetic mechanism controls β-catenin activity in response to ETAR activation, deciphering a novel function for α-arr1 as signal transducer for the nuclear compartmentalization of ETAR signalling in promoting tumor metastasis. Supported by AIRC, AstraZeneca

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 3086. doi:1538-7445.AM2012-3086
Abstract 3089: Regulation of GFI proteins by Notch intracellular domains
Authors: Andrade Daniel L. , Bareyan Diana , Singer Jason , Quinton Ryan , Engel Michael
Published: August 2012

Growth factor independence (GFI)-1 and its homolog, GFI1B, are transcriptional regulators that play critical roles during hematopoiesis. GFI family proteins are characterized by near-invariant SNAG and zinc finger domains that direct transcriptional repression and DNA-binding, respectively. A linker region with limited homology and unknown function separates the conserved SNAG and zinc-finger regions. GFI proteins display distinct expression patterns within the myelo-erythroid compartment and make similarly distinct contributions to cell fate specification. GFI1 expression is necessary for hematopoietic stem cell maintenance and is required for granulocytic differentiation beyond the promyelocyte stage. Enforced expression of GFI1 promotes IL-2-independent growth of hematopoietic progenitors and inhibits apoptosis. Mutations in GFI1 lead to a severe congenital neutropenia syndrome that carries an increased risk of myeloid leukemia development. GFI1B expression predominates in erythroid and megakaryocytic precursors and is required for terminal differentiation along both lineages. Moreover, elevated GFI1B expression occurs preferentially in erythroid and megakaryoblastic leukemias, and contributes to the malignant phenotype by supporting growth and preventing apoptosis. Given their complementary roles as growth and survival factors, yet distinct contributions to lineage allocation in hematopoiesis, it is essential to define how GFI family proteins are integrated into the signaling machinery governing cell fate specification. We show that both GFI1 and GFI1B interact with intracellular domains of Notch receptors. Enforced expression of the Notch1 intracellular domain (N1-ICD) impairs GFI-mediated transcriptional repression. Using deletion mutagenesis, we have mapped the regions required for the N1-ICD–GFI1 interaction. Both the ankyrin repeat and transactivation domains of N1-ICD contribute binding surfaces for GFI1. In reciprocal mapping experiments, we show that N1-ICD binding to GFI1 requires a 128-amino acid motif in the divergent linker region near the zinc finger repeat elements. This region contains a high probability consensus sumoylation element that is absolutely conserved in mammalian species but not present in GFI1B. These data suggest that Notch activation may directly impact transcriptional targets regulated by GFI family proteins and expand the potential sphere of influence for Notch in hematopoietic 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 3089. doi:1538-7445.AM2012-3089
Abstract 309: Induction of activation-induced cytidine deaminase (AID) by dendritic cells leads to genomic instability in human myeloma
Authors: Koduru Srinivas , Wong Ellice , Strowig Till , Sundaram Ranjini , Zhang Lin , Strout Matthew P. , Flavell Richard A. , Schatz David G. , Dhodapkar Kavita M. , Dhodapkar Madhav V.
Published: August 2012

Tumor microenvironment (TME) is often implicated in regulating the growth of tumors, but whether it can directly alter the genetics of tumors is not known. Myeloma is a plasma cell malignancy characterized by growth of tumor cells in the bone marrow. Prior studies have shown that genomic instability and dendritic cell (DC) infiltration are common features of human myeloma (MM). Mechanisms underlying genomic instability in MM are largely unknown. Here we show that the interaction between myeloma and DCs but not monocytes, leads to rapid induction of the genomic mutator AID and AID-dependent DNA double-strand breaks (DSBs) in myeloma cell lines as well as primary MM cells. Both myeloid as well as plasmacytoid DCs known to infiltrate MM lesions have the capacity to induce AID in MM tumor cells. The induction of AID and resultant DNA-DSBs in tumor cells by DCs depends on DC-tumor contact and is inhibited by the blockade of RANK/RANKL interactions. DC-mediated genomic damage in tumors also leads to altered tumorigenicity in vivo. These data demonstrate a novel pathway for the capacity of specific cells in TME such as DCs to regulate genomic integrity in cancer. These findings also suggest that DC-mediated genomic instability may be targetable by approaches such as RANKL inhibition that are already in the clinic.

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 309. doi:1538-7445.AM2012-309
Abstract 3090: Oncogenic ETS transcription factors bind ETS/AP-1 sequences and activate a RAS/MAPK gene expression program in the absence of MAPK activation
Authors: Hollenhorst Peter C. , Ferris Mary W. , Hull Megan A. , Chae Heejoon , Kim Sun , Graves Barbara J.
Published: August 2012

Deciphering the mechanism of transcription factor function in both normal and disease states requires understanding how these proteins are targeted to specific genomic binding sites, influence transcription, and how these functions are modified by signaling pathways. However, overlapping functions among the thousands of transcription factors encoded by the human genome have made it difficult to assign specific mechanisms. Approximately 50% of prostate cancers have chromosomal rearrangements resulting in the over-expression any one of four ETS-family transcription factors. It is not known why these four ETS family members are associated with prostate cancers, while the other 24 human ETS genes are not. We found that the four oncogenic ETS family members have a specific role in prostate cell migration that does not extend to other family members. Using chromatin immunoprecipitation coupled with next-generation sequencing (ChIP-seq), this specific biological function was matched to a specific set of genomic targets highlighted by the presence of both ETS and AP-1 binding sequences. ETS/AP-1 binding sequences are prototypical RAS-responsive elements where a MAPK can phosphorylate ETS proteins increasing transcriptional activation. We found that oncogenic ETS proteins could activate a RAS/MAPK transcriptional program when the MAPK pathway was inactive. These findings indicate that a specific function of ETS proteins over-expressed in prostate cancer is the activation of a RAS/MAPK gene expression program in the absence of activating mutations in the RAS/MAPK signaling pathway. We propose that this ETS/AP-1 regulated, RAS-responsive, transcriptional network will also play a critical role in other cancers that do not over-express an ETS protein, but have activating mutations in the RAS/MAPK pathway.

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 3090. doi:1538-7445.AM2012-3090
Abstract 3094: Interferon-α induced TLR4 is indispensable for the synergistic induction of Duox2/DuoxA2 by lipopolysacharide (LPS) and IFN-γ in human pancreatic cancer cells
Authors: Wu Yongzhong , Lu Jiamo , Antony Smitha , Juhasz Agnes , Liu Han , Jiang Guojian , Roy Krishnendu , Doroshow James
Published: August 2012

Several bacterial cell wall components, including lipopolysaccharide (LPS), muramyldipeptide (MDP), and flagellin, have been shown to engage their corresponding receptors and mediate NADPH oxidase (NOX)-dependent reactive oxygen species (ROS) generation that may be involved in wound healing, host defense, and the inflammatory response in airway and gastrointestinal epithelial cells. Previously, we reported that two human pancreatic cancer cell lines, BxPC-3 and AsPC-1, respond to the pro-inflammatory cytokine IFN-γ by upregulating the expression of both Dual oxidase 2 and its cognate cofactor DuoxA2 resulting in enhanced ROS production. It has also been reported that human pancreatic cancer cells express TLR4/MyD88, and that signaling downstream of the TLR receptor may be responsible for LPS-induced invasiveness of pancreatic cancer cells. In our studies, we have demonstrated that IFN-γ up-regulates TLR4 and its adaptor protein MyD88 expression in BxPc-3 cells and augments the response of these cells to LPS, resulting in the activation of NFkB signaling, enhancing p65 subunit accumulation in the nucleus. Moreover, we found that p65 binds to the Duox2 promoter, and cooperates with the IFN-γ- induced Stat1 expression to synergistically enhance Duox2/DuoxA2 expression, leading to persistent intra- and extracellular ROS accumulation. TLR4 silencing by RNAi and two independent NF-kB inhibitors (PDTC and BAY11-70829) specifically attenuate LPS- and IFN-γ-mediated Duox2 expression in BxPc-3 cells, underscoring the importance of TLR4 engagement and the activation of NF-kB signaling in regulating Duox2 expression and subsequent ROS generation by LPS and IFN-γ. Our data suggest that sustained extracellular H2O2 accumulation, mediated by LPS- and IFN-γ- induced Duox2/DuoxA2 expression, may contribute to the deleterious effects of cytokine-mediated pancreatic 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 3094. doi:1538-7445.AM2012-3094
Abstract 3102: Hexavalent chromium induces chromosome instability leading to DNA double strand break repair deficiency and neoplastic transformation
Authors: Wise Sandra S. , Holmes Amie L. , Xie Hong , Thompson W. Douglas , Wise John P.
Published: August 2012

Chromosome instability (CIN) is a hallmark of lung cancer with cells exhibiting both translocations and aneuploidy. Hexavalent chromium (Cr(VI)) is a well known respiratory carcinogen. The ability of Cr(VI) to induce chromosomal translocations is unknown. We exposed human lung cells to lead chromate for three sequential 24 h periods, each separated by about a month. After each treatment, cells were seeded at colony forming density, cloned, expanded and retreated. Each generation of clones was tested for chromium sensitivity, chromosome complement, ability to repair DNA double strand breaks (DSB), and growth in soft agar. We found that after the first treatment, lead chromate-treated cells exhibited a normal chromosome complement though a few clones showed a decrease in cell survival. After the second exposure, more than half of the clones acquired an abnormal karyotype including numerical and structural changes. The third treatment resulted in additional abnormal clones as well as previously abnormal clones acquiring more abnormalities. Clones were treated with soluble Cr(VI) for 24 h followed by a 24 h recovery period to measure DNA DSB repair. Abnormal clones showed persistent H2A.X and 53BP1 foci formation after 24 h recovery suggesting that these clones had acquired a DNA DSB repair-deficient phenotype. In addition, clones from the third generation were able to form colonies in soft agar suggesting that the cells have neoplastically transformed. This work was supported by NIEHS grant ES016893 (J.P.W.) and the Maine Center for Toxicology and Environmental Health.

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 3102. doi:1538-7445.AM2012-3102
Abstract 3115: PARP overactivation predicts the susceptibility of human cancer cells to apoptosis induction by PARP inhibitors
Authors: Michels Judith , Vitale Ilio , Galluzzi Lorenzo , Kepp Oliver , Senovilla Laura , Olaussen Ken André , Soria Jean-Charles , Castedo Maria , Kroemer Guido
Published: August 2012

Chemical inhibitors of poly(ADP)ribose (PAR) polymerases (PARP) have generated raising expectations in cancer treatment, either as monotherapeutic agents for the therapy of tumors that are deficient in DNA repair by homologous recombination, or combined with DNA-damaging compounds. Results from early clinical trials suggest that PARP inhibitors are well tolerated, and would be particularly useful for BRCA1- and BRCA2-mutated tumors. However, as these tumors constitute a minor fraction of all cancers, the main challenge is to extend the efficacy of PARP inhibitors to BRCA-proficient tumors, calling for the need of reliable biomarkers that predict the efficiency of PARP inhibitor-based therapy. Here, we report the effects of two chemically distinct PARP inhibitors, the phenanthridinone PJ34 and the 4-methoxy-carbazole derivate CEP8983, on non-small cell lung cancer (NSCLC) cells exhibiting increased PARP activity. We found that PAR polymers are a predictive marker of the sensitivity of NSCLC cells to PARP inhibitors. We were able to confirm these findings in mesothelioma, cervical cancer and ovarian cancer cell lines that are characterized by constitutively increased expression of PARP (as monitored by immunoblotting with a PARP1-specific antibody) as well as enhanced PARP enzymatic activity (as detected by immunoblotting with an antibody that recognizes poly(ADP)ribosylated proteins). Upon treatment with PARP inhibitors, cells with hyperactivated PARP exhibited signs of DNA damage (as assessed by immunofluorescence microscopy with an antibody that recognizes the phosphorylated form of histone 2AX) and underwent cell death via the intrinsic pathway of apoptosis (as monitored by immunofluorescence microscopy with antibodies for the detection of cytochrome c and active caspase-3). The chemosensitizing or cell death-inducing effects of PJ34 and CEP8983 were mimicked by PARP1- and PARP2-specific siRNAs, suggesting that they are indeed mediated by PARP inhibition. Moreover, PARP inhibitors efficiently reduced the growth of NSCLC xenografts exhibiting increased PARP activity (as evaluated by immunohistochemistry for poly(ADP)ribosylated proteins on paraffin embedded xenografts). Altogether, our results indicate that PARP overactivation reflects the susceptibility of NSCLC cells to apoptosis induction by PARP 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 3115. doi:1538-7445.AM2012-3115
Abstract 3176: miR-211 promotes the progression of head and neck carcinomas by targeting TGFβRII
Authors: Chu Ting-Hui , Chang Kuo-Wei
Published: August 2012

Head and neck squamous cell carcinoma (HNSCC) is among the prevalent neoplasms in the world. More than 50% patients die within 5 years after initial therapy due to local recurrence, invasion or metastasis. Previous studies have shown that transforming growth factor-beta type II receptor (TGFβRII) deprivation could promote HNSCC metastasis. Our histolopathological analysis revealed that TGFβRII was down-regulated in metastatic tumors relative to primary HNSCC. This study aimed to address the roles of microRNAs in regulating TGFβRII for HNSCC progression. In silico modules predicted that miR-211 and miR-370 might target TGFβRII. TGFβRII was further confirmed to be a target of miR-211 in HNSCC cells by means of reporter assay, quantitative RT-PCR analysis and Western blot analysis. Interestingly, TGFβRII and miR-211 were inversely expressed during the metastasis process of HNSCC. In HNSCC cell lines, the inhibition of TGFβRII by miR-211 attenuated the Smad3 phosphorylation and increased cell migration, while ectopic Smad3 expression decreased cell migration drastically. In agreement with previous findings that the disruption of TGFβ/Smad pathway could benefit HNSCC progression, this study further specified that miR-211 played crucial regulatory roles in the suppression of TGFβ/Smad pathway for HNSCC progression by targeting TGFβRII. To elucidate the in vivo oncogenic role of miR-211 in HNSCC carcinogenesis, we established K14 promoter driven miR-211 transgenic mice with stable expression of miR-211 in the basal epithelial layers of skin and oral mucosa. By administrating of 4-nitroquinoline 1-oxide in drinking water to induce tongue tumors, the transgenic mice exhibited higher potential for the induction and advances of tumors relative to controls. This study concludes that miR-211 promotes HNSCC progression by targeting TGFβRII and intercepting TGFβ/Smad signaling pathway.

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 3176. doi:1538-7445.AM2012-3176
Abstract 3187: Ex vivo characterization of CTCs isolated using the FMSA device
Authors: Cheng Hairong , Gallant Jean-Nicolas , Harouaka Ramdane , Zheng Siyang , El-Deiry Wafik
Published: August 2012

Although technological advances in recent years have enabled isolatation of circulating tumor cells (CTCs), only the VeridexCellSearch System has been approved by the FDA for assessment of patient prognosis in metastatic breast, colon, and prostate cancers. A fundamental challenge with the CellSearch System is that the technique it uses to enrich and detect CTCs, EpCAM-basedimmunomagnetic isolation, fixates captured cells and prevents further molecular characterization by functional assays and primary cell culture. Progress in addressing these issues may help with progress with a variety of clinical needs including further characterization of the biology of individual patient tumors as well as their potential response top various therapeutics. In this study, we use the Flexible Micro Spring Array (FMSA) Device —a novel portable microfluidic device that captures and isolates viable CTCs by two physical parameters: size and flexibility—to capture, culture, and further characterize CTCs.GFP-labeled HCT-116 cells were spiked into healthy samples of donor blood to mimic blood samples of metastatic cancer patients. This spiked blood was filtered using the FMSA device, and the recovered cells were expanded in cell culture. A series of experiments were carried out to characterize these cells and investigate the effect of chemotherapy on the resulting cultures. Studies are ongoing to evaluate the potential of using this model to culture CTCs from patients and to evaluate the response of these cells to chemotherapies using high-throughput methodologies. The isolation of viable CTCs from human blood using the FMSA device provides a novel means for studying viable CTCs and for testing drug efficacy ex vivo. The analysis and identification of CTC-specific characteristics and their relation to chemotherapy susceptibility suggests a potential paradigm shift toward personalized and targeted cancer therapy based on the specific genetic defects of each patient's malignancy and CTCs.

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 3187. doi:1538-7445.AM2012-3187
Abstract 3266: Interaction of MCM7 and RACK1 for activation of MCM7 and cell growth
Authors: Luo Jian-Hua , Zhang Xi-Yue , Yu Yan Ping
Published: August 2012

MCM7 is one of the pivotal DNA replication licensing factors in controlling DNA synthesis and cell entry into S phase. Its expression and DNA copy number are some of the most predictive factors for the growth and behavior of human malignancies. In this study, we identified that MCM7 interacts with receptor for activated protein kinase C 1 (RACK1), a protein kinase C (PKC) adaptor in vivo and in vitro. The RACK1 binding motif in MCM7 is located at the amino acid 221-248. Knocking down of RACK1 significantly reduced MCM7 chromatin association, DNA synthesis and cell cycle entry into S phase. Activation of PKC by 12-O-tetradecanoylphorbol-13-acetate dramatically decreased MCM7 DNA replication licensing and induced cell growth arrest. Activation of PKC induced redistribution of RACK1 from nucleus to cytoplasm, and decreased RACK1-chromatin association. MCM7 mutant that does not bind RACK1 has no DNA replication licensing nor oncogenic transformation activity. As a result, this study demonstrates a novel signaling mechanism that critically controls DNA synthesis and cell cycle progression.

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 3266. doi:1538-7445.AM2012-3266
Abstract 3273: A robust transgenic mouse model to study male breast cancer
Authors: Krause Silva , Tobin Heather , Lurvey Heidi L. , Ingber Donald E.
Published: August 2012

Male breast cancer accounts for about 1% of all breast cancers and even though it is a rare disease, the incidence rate has increased steadily during the past 20 years. Study of the male form of the disease has been hampered by a lack of relevant animal models as it is commonly believed that male mammary glands do not contain ducts. Female FVB C3(1)-SV40Tag transgenic mice spontaneously develop hyperplastic mammary lesions that progress to invasive mammary tumors, whereas most of the transgenic males develop prostatic hyperplasia that progresses to adenocarcinoma. However, upon closer examination, we discovered that approximately 55% of transgenic males develop mammary tumors by 40 weeks of age, often prior to developing prostate tumors. The course of male mammary development is similar to that observed in the females but with a later onset. Hyperplastic ducts form as early as 15 weeks of age and progress into DCIS-resembling tumors before developing into invasive tumors that invade locally into adipose tissue and muscle and occasionally form metastases to lung and other organs. We then examined male mammary development in the FVB background strain (wild type) and showed that all males develop mammary ducts that continue to grow and branch throughout adulthood. The morphology of these ducts was similar to that of females with a central lumen surrounded by concentric layers of luminal epithelium, myoepithelium, a basement membrane and surrounding stroma. A study of CD1 male mice confirmed that male mammary development was not specific to the FVB strain but that CD1 males showed similar mammary ductal development. Male mammary development in FVB wild type animals and tumor progression in the transgenic males was characterized in terms of cell proliferation, apoptosis and expression of various markers of differentiation including hormone receptor status. In summary, our results demonstrate that FVB C3(1)-SV40Tag transgenic males represent a highly robust and reproducible model for the study male breast cancer. Our long-term goal is to leverage the information we uncovered through this effort to design novel therapies for breast cancer treatment in men.

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 3273. doi:1538-7445.AM2012-3273
Abstract 3277: Increased mitogen-activated protein kinase kinase 4 (MEK4) induces metastasis in an orthotopic murine model of prostate cancer
Authors: Pavese Janet M. , Ogden Irene , Huang Xiaoke , Bergan Raymond
Published: August 2012

Mitogen-activated protein kinase kinase 4 (MEK4) is a dual-specificity kinase that has been implicated in prostate cancer (PCa) progression. Increased MEK4 expression is observed in invasive cancer lesions in human prostate tissue. We have demonstrated the clinical importance of this in vitro, as MEK4 increases human PCa invasion. This phenotype is driven by increased protease production, and not via changes in cell migration. However, it is not known whether MEK4 regulates human PCa metastasis. This is of high importance as MEK4 has shown differential effects in various cancer models in a cell type specific fashion, and may therefore represent an important human PCa specific target. To emulate the situation of sustained altered MEK4 expression in humans, we engineered MEK4 clonal variant cell lines, generating multiple clones each for vector control (VC), increased wild type (WT), and increased constitutively-active mutant MEK4 (CA). Using a murine orthotopic implantation model designed to characterize in vivo behavior, we implanted 75 mice with these clones and demonstrated that both WT and CA MEK4 increase human PCa metastasis to the lung, a clinically relevant site in humans. In the primary tumor, interestingly, WT tumors were not increased compared to VC, while CA tumors were. Additionally, increased MMP-2 and MMP-10 were observed in both WT and CA tumors. However, MMP-9 was increased in WT tumors only, and MMP-13 in CA tumors only. Currently, we are expanding our efforts at characterizing additional molecular changes in primary tumor between these groups. Outside of the primary tumor, we isolated circulating tumor cells in the blood and bone marrow. We are currently characterizing their relevant cellular and molecular parameters. Using a clinically relevant murine model we have shown that increased MEK4 increases human PCa metastasis to the lung and protease production within the primary tumor. Further, a constitutively active phenotype drives tumor growth and circulating tumor cell formation.

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 3277. doi:1538-7445.AM2012-3277
Abstract 3280: Loss of the tumor suppressor APC in cells expressing lysozyme M results in murine endometrial hyperplasia
Authors: Kitchen-Goosen Susan M. , Sternberger Sarah C. , Alberts Arthur S.
Published: August 2012

The Adenomatous polyposis coli (APC1) tumor suppressor is a multi-function protein that is involved in both the Wnt signaling cascade and cytoskeletal remodeling. Mutations or loss of APC1 can result in defects in cell migration, proliferation, and differentiation. APC frequently collaborates with the canonical Diaphanous-related formin, mDia1 (DIAPH1), which also functions to regulate cytoskeletal dynamics. APC1 and DIAPH1 are genetically linked on Chromosome 5q in a region frequently disrupted in myeloproliferative neoplasms (MPNs). Mice lacking mDia1 (Drf1) and the Apc min mice develop myelodysplastic phenotypes. The physical and functional linkage of APC and mDia1 as 5q tumor suppressors and in cytoskeletal remodeling led us to explore the role of APC in tumor suppression in myeloid-derived cell lineages. We created a mouse which lacks APC in myeloid lineage cells by breeding Apc-flox mice with mice expressing Cre recombinase under the control of lysozyme M (LyzsM) gene promoter. Lysozyme M is expressed in myeloid lineage cells including monocytes, macrophages and granulocytes. Surprisingly, the female mice develop cystic endometrial hyperplasia and are unable to sustain pregnancy. Lysozyme M expression appears to be limited to tissue resident macrophages within the uterus and was not detected in uterine epithelial cells. However, there is a small subset of uterine epithelial cells with increased β-catenin expression, suggesting that these cells lack APC. This subset of cells has elevated expression of cyclin D1, a regulator of cell cycle progression and a downstream effector of Wnt signaling, resulting in increased proliferation. Interestingly, the uterine epithelial cells with increased β-catenin expression also have increased estrogen receptor ≤ (ERα) expression. Estrogen stimulates uterine growth and unopposed estrogen signaling is a hallmark of Type I endometrial cancer. It is unclear if the endometrial hyperplasia seen in these mice is due to lysozyme M expression early on in uterine epithelial cell development or perhaps in a progenitor cell population. A second alternative is that loss of APC in tissue resident myeloid cells residing in the uterine stroma affects epithelial morphology. Regardless, these data suggest that APC plays a role in uterine tissue homeostasis, perhaps even regulating ERα expression.

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 3280. doi:1538-7445.AM2012-3280
Abstract 3289: Tissue specific expression of the PI 3-kinase mutation Pik3caH1047R induces hyperplasia and tumorigenesis in a mouse model
Authors: Kinross Kathryn M. , Tikoo Anjali , Hare Lauren , Montgomery Karen G. , Phillips Wayne A.
Published: August 2012

Mutations in the p110α subunit of phosphoinositide 3-kinase (PI3K) (encoded by the gene PIK3CA) are frequent in human cancers. To better understand the role of mutant PIK3CA in the initiation or progression of tumorigenesis in vivo, we generated a conditional (Cre recombinase-inducible) knock-in mouse model of the common activating mutation, Pik3caH1047R, expressed from the endogenous locus. We have then targeted the mutation to specific tissues by crossing our mouse to mice expressing Cre under the control of tissue-specific promoters. The mouse mammary gland was targeted using a transgenic mouse expressing Cre under the control of the mouse mammary tumor virus promoter (MMTV-Cre). To target the gastrointestinal tract, we used the A33CrePR2 mouse, expressing Ru486-inducible version of Cre under the control of the gpa33 promoter. Tumors were formed in both these models but only following a long latency (>15 months) suggesting that a ‘second-hit’ may be necessary for tumor development. Similarly, activation of this mutation in the mouse ovary, by injection of an adenovirus expressing Cre into the ovarian bursa, revealed that Pik3caH1047R alone is a weak activator of AKT capable of inducing premalignant hyperplasia in ovarian surface epithelium. Interestingly, we found that combining Pik3caH1047R mutation with deletion of Pten in the mouse ovary resulted in robust epithelial AKT signaling and progression to ovarian serous adenocarcinomas and granulosa cell tumors within 6 months. Therapeutic inhibition of PI3K/mTOR in these mice delayed tumor growth and prolonged survival. This novel mouse is proving to be a fascinating model with which to explore the biological consequences and clinical significance of Pik3caH1047R mutation in diverse tissue types and a valuable tool for the preclinical evaluation of PI3K pathway 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 3289. doi:1538-7445.AM2012-3289
Abstract 329: Downregulation of PKC∈/par3/par6 polarity complex is critical for hypoxia-induced epithelial-mesenchymal transition, migration, and invasion in lung cancer cells
Authors: Zhou Qiyuan , Chen Tianji , Ibe Joyce Christina F. , Raj J. Usha , Zhou Guofei
Published: August 2012

Rationale: We have previously reported that hypoxia induces epithelial-mesenchymal transition (EMT) in lung cancer cells. EMT has been known to contribute to tumor cell invasion and metastasis. Recent evidence suggests that loss of cell polarity complex, which consists of atypical protein kinase C ≤ (PKC∈), Par (partitioning defective) 3, and Par6, is strongly correlated with malignancy. However, it is unknown whether hypoxia-induced cancer cell migration, invasion, and metastasis are caused by the loss of PKC∈/Par3/Par6 polarity complex and subsequent EMT. Methods: We incubated A549 in hypoxic conditions (1.5% O2) for a period of time and assessed the protein abundance of α-SMA, vimentin, E-cadherin, PKC∈, Par3, and Par6 as well as PKC∈ ubiquitination. Next we knocked down PKC∈/Par3/Par6 by siRNAs and determined the abundance of α-SMA, vimentin, and E-cadherin. We also measured cell migration and invasion after knockdown of PKC∈/Par3/Par6 in vitro. In addition, we established A549 cells with knockdown of Par3 and determined cell proliferation rate and lung colonization in a mouse tail-vein injection model, in which lung cancer cells were injected intravenously into the tail vein of mice and lung metastatic foci were quantified in five weeks. Furthermore, we obtained human lung adenocarcinoma tissue samples and self-matched adjacent normal tissues as well as unmatched normal tissues and detected the expression levels of PKC∈/Par3/Par6 polarity complex. Results: We found that A549 cells exposed to hypoxia expressed decreased PKC∈/Par3/Par6 polarity complex and E-cadherin and increased expression of α-SMA and vimentin, suggesting that loss of PKC∈/Par3/Par6 polarity complex is associated with the induction of EMT. We also showed that hypoxia increased ubiquitination of PKC∈. Our results also showed that loss of either of PKC∈, Par3, or Par6 resulted in EMT, elevated migration and invasion, and increased the numbers of metastatic foci in the lungs. Moreover, we show that human lung adenocarcinoma tissues express less Par6 protein than the adjacent normal tissues. Conclusions: These results suggest that in lung cancer cells hypoxia downregulates PKC∈/Par3/par6, leading to EMT and increased cancer cell migration, invasion, and colonization. Support: UIC Faculty Scholarship Support Program and the University of Illinois Cancer Center Pilot Subsidy Program.

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 329. doi:1538-7445.AM2012-329
Abstract 3305: The role of carbonic anhydrase IX in tumor hypoxia, metastasis and the cancer stem cell niche
Authors: Lock Frances E. , McDonald Paul C. , Lou Yuanmei , Supuran Claudiu T. , Dedhar Shoukat
Published: August 2012

Carbonic anhydrase IX (CAIX) is a hypoxia and HIF-1 inducible protein that regulates intra- and extracellular pH under hypoxic conditions, and promotes tumor cell survival and invasion in hypoxic microenvironments. shRNA-mediated depletion of CAIX expression in mouse and human metastatic breast cancer cells, capable of inducing CAIX in hypoxia, resulted in regression of orthotopic mammary tumors and inhibition of spontaneous lung metastasis formation. CAIX depletion led to caspase-independent cell death and reversal of extracellular acidosis under hypoxic conditions in vitro. In addition, the CD44+/CD24-/low “cancer stem cell” compartment, which exhibited hallmarks of EMT (E-cadherin low/SMA high) was significantly enhanced in hypoxia, but was severely depleted in shRNA-CAIX knock-down cells as well as in cells treated with CAIX small molecule inhibitors. CAIX depletion or inhibition of its activity prevented mesenchymal conversion of the stem cells and also resulted in the suppression of expression of several EMT and “stemness” regulator genes. Treatment of mice harboring CAIX-positive 4T1 and MDA-MB-231/LM2 mammary tumors with novel CAIX-specific small molecule inhibitors that mimicked the effects of CAIX depletion in vitro resulted in significant inhibition of tumor growth and metastasis formation in both spontaneous and experimental models of metastasis, without any inhibitory effects on CAIX negative tumors, or any adverse toxic effects. This was associated with significant depletion of cells expressing “cancer stem cell” markers. Furthermore, interrogation of 3,630 human breast cancers revealed CAIX to be an independent poor prognostic biomarker for distant metastases and survival. Our findings demonstrate that CAIX is vital for the survival of “cancer stem cells” in hypoxic niches as well as for the growth and metastasis of hypoxic breast tumors. It is a specific, targetable biomarker for breast cancer metastasis.

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 3305. doi:1538-7445.AM2012-3305
Abstract 3307: Improved survival in AML by in vivo drug targeting of conserved regulatory pathways in phenotypically distinct tumor-initiating compartments
Authors: Gibbs Kenneth D. , Jager Astraea , Crespo Oliver , Goltsev Yury , Tejo Angelica , Richard Chase , Nolan Garry
Published: August 2012

Increasing evidence suggests tumors are maintained by cancer stem cells, however their nature remains controversial. In a HoxA9-Meis1 (H9M) driven model of acute myeloid leukemia (AML), we found that tumor-initiating activity existed in three, immunophenotypically distinct compartments, corresponding to disparate lineages on the normal hematopoietic hierarchy–stem/progenitor cells (Lin−kit+), and committed progenitors of the myeloid (Gr1+kit+) and lymphoid lineages (Lym+kit+). Each compartment clonally recapitulated the original range of tumor cell immunophenotypes in vivo, including cells with a less-differentiated immunophenotype. These distinct populations largely shared signaling networks, and in vivo pharmacologic targeting of shared pathways (DNA methyltransferase and MEK phosphorylation) significantly increased survival. Collectively, these data show that H9M AML is organized as an atypical hierarchy that defies the strict lineage marker boundaries and unidirectional differentiation of normal hematopoiesis. Moreover, in some malignancies, tumor-initiation ability (or “cancer-stemness”) can represent a targetable, cellular state that can exithat exists independently of distinct immunophenotypic definition.

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 3307. doi:1538-7445.AM2012-3307
Abstract 331: Epithelial-mesenchymal transition confers resistance to complement-dependent cytotoxicity in lung cancer cells
Authors: Goswami Moloy T. , Reka Ajaya K. , Kurapati Himabindu , Kaza Viritha , Keshamouni Venkateshwar G.
Published: August 2012

Recent studies have implicated Epithelial-mesenchymal transition (EMT) in conferring several clinically relevant properties to cancer cells, in addition to initiating tumor metastasis. These include stem-cell like properties, resistance to targeted therapies and ability to evade immune surveillance. Pathway analysis of gene expression changes in TGF-β induced EMT identified the complement cascade as one of the significantly enriched pathway. Further analysis of the genes in the complement pathway revealed EMT-induced expression of complement inhibitors and decrease in expression of proteins essential for complement activity, suggesting resistance to complement dependent cytotoxicity (CDC) during EMT. We found lung cancer cells that undergo EMT showed marked decrease in C3 deposition and concomitant resistance to apoptosis by CDC as measured by 7-Aminoactinomycin D staining. Flow cytometric and RT-PCR analysis showed a significant increase in the CD59 expression on the surface of cells undergoing EMT, which is a potent inhibitor of formation of membrane attack complex that mediates complement dependent cell lysis. Furthermore, CD59 inhibition by siRNA mediated knock-down overcame the EMT-induced resistance to anti-EGFR antibody (Cetuximab) mediated CDC. The increase in CD59 was abrogated on disruption of TGF-β signaling as revealed by TGF- β Receptor kinase inhibitor and is dependent on Smad3 signaling. Chromatin immunoprecipitation analysis revealed increased occupancy of Smad3 on CD59 promoter, suggesting a direct regulation by Smad3. These results demonstrate that TGF-β-induced EMT confers another novel immune evasive mechanism to tumor cells that facilitates tumor progression and CD59 as a potential therapeutic target for enhancing the efficacy of anti-EGFR Antibody therapies and against tumor metastasis.

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 331. doi:1538-7445.AM2012-331
Abstract 3316: The stem cell marker nestin inhibits growth and invasion of malignant melanoma
Authors: Akiyama Michiko , Matsuda Yoko , Hagio Masahito , Kawahara Kiyoko , Suzuki Taeko , Ishiwata Toshiyuki , Kawana Seiji , Naito Zenya
Published: August 2012

BACKGROUND: Nestin, a class VI intermediate filament protein, was first described as a neural stem cell/progenitor cell marker. Nestin was detected in various neoplasms, and its expression level has relevance to the poor prognosis in some tumors, including malignant melanomas. Recently, nestin was reported as one of the cancer stem cell markers in melanomas. Furthermore, nestin is expressed in circulating tumor cells of melanoma patients, and its expression was found to be correlated with the prognosis. These reports indicate that nestin plays important roles in melanomas, and has the possibility of becoming a therapeutic target in melanomas. In the present study, we used a silencing strategy of nestin to clarify the effectiveness of nestin-targeting therapy in malignant melanomas. METHODS: We constructed a plasmid vector of short hairpin RNA (shRNA) tageting nestin and scramble vector as a negative control. Human malignant melanoma cells, A375 cells, were stably transfected with these vectors. Using nestin-shRNA-transfected cells, scramble vector-transfected cells, and wild-type cells, we analyzed cell growth, sphere formation, and invasion in vitro. Activation of the AKT/MAPK pathway was analyzed using a phosphorylated protein array. To determine the effect of nestin-knockdown in vivo, we performed tail vein injection of transfected and wild-type A375 cells into nude mice, and analyzed the metastatic tumor formation in 5 weeks. RESULTS: Nestin shRNA transfection suppressed cell growth, invasion, and sphere formation of A375 cells in vitro. In the protein array, the suppression of nestin decreased the phosphorylation of AKT and p53. The incidence of liver metastasis in nude mice was 100% in wild-type cell-injected mice, 75% in scramble vector-transfected cell-injected mice, and 16.7% in nestin-shRNA-transfected cell-injected mice. CONCLUSION: These findings suggest that nestin regulates cell growth, stemness, invasion, and metastasis of melanomas, in part, by alterling the phosphorylation of the MAPK/AKT pathway. Nestin may be a candidate therapeutic target in malignant melanomas.

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 3316. doi:1538-7445.AM2012-3316