bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2304: Stem features associated with EMT are driven by TGFβ1 in liver-metastatic cells
Authors: Zubeldia Idoia G. , Gil-Puig Carmen , Calvo Alfonso , Larzabal Leyre , Agliano Alice , Dotor Javier , Vidal-Vanaclocha Fernando , Lecanda Jon 
Published: February 2011

Abstract
The liver is a major target organ for metastasis. Development of metastases requires an early release of tumour-initiating-cells from the primary tumour and adhesion of metastatic-cells into a permissive niche. We hypothesized that Epithelial-Mesenchymal Transition (EMT) underlies not only the early events, but also the promotion of the most advanced stages of a successful dissemination process to the liver. It is believed that TGFβ1 might allow tumour-initiating-cells to acquire cancer stem cell properties via EMT as a mechanism that modulates the microenvironment contributing to primary and also metastatic tumor progression. However, the mechanism of EMT induction by TGFβ1 and its involvement in liver metastases remain largely unknown. Aiming to recapitulate the hepatic metastases, we established a murine model of highly metastatic colon carcinoma cells in the context of TGFβ1-signaling. To this end, luciferase-expressing cells (MC-38luc) were pre-treated with TGFβ1 (100 pM, 48 h), before intrasplenic injection of 106 cells in C57BL/6J mice. Larger primary tumours were consistently observed and liver metastasis was achieved more rapidly after injection of MC-38luc+TGFβ1 cells, than after injection of untreated MC-38luc cells. Histological examination of liver micrometastasis also revealed slightly increased staining of Ki67, α-SMA and F4/80 markers in MC-38luc+TGFβ1 tumours. Splenic co-injection of these liver-metastatic-stem cells with non transformed hepatocytes (AML-12 cells) accelerated the incidence of liver metastasis, indicating the supportive role of the normal hepatic parenchyma. Intraperitoneal injection with a novel TGFβ1-inhibitory peptide P17 (obtained from a peptide library binding to TGFβ1) resulted in reduced liver metastasis and decrease of both CECs and CEPs. We isolated liver-metastatic cells that showed higher cellular proliferation as compared to the parental counterparts. These cells posses increased tumorogenicity in vivo, a complete lack of E-cadherin expression, and increased TGFβ1/EMT signalling properties that all relate to stem cell features. Our results provide an insight into the molecular events leading to TGFβ1-mediated malignant progression and indicate that targeting TGFβ1/EMT might represent an optimal therapeutic strategy by impairing tumor growth, stemness and further liver metastasis.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2304.
Abstract 2318: Induction of Rac1b by MMP-3 causes lung tumors by activating EMT
Authors: Stallings-Mann Melody L. , Zhang Ying , Miller Erin , Radisky Derek 
Published: February 2011

Abstract
During development, epithelial cells acquire mesenchymal characteristics through a process known as epithelial-mesenchymal transition (EMT). Substantial evidence now exists that EMT-related processes play a major role in tumor progression. EMT is a focus of interest in lung cancer as loss of E-cadherin expression confers increased resistance to several types of chemotherapy. In previous studies, we found that matrix metalloproteinase-3 (MMP3) induced EMT in mouse mammary epithelial cells through induction of Rac1b, an alternatively spliced isoform of Rac1. We now show that exposure to MMPs stimulates Rac1b and induction of EMT markers in human lung cancer cell lines, and that knockdown of Rac1b blocks MMP induced EMT. We also show that Rac1b expression levels in human lung tumor biopsies is predictive of patient outcome, and that Rac1b and MMP expression levels are correlated in these samples, suggesting a direct relationship. We also describe the generation of new transgenic mouse models for which MMP3 or Rac1b is inducibly expressed in lung epithelial cells; activation of kRAS in these mice reveals that expression of MMP3 or Rac1b promotes increased tumor number, size, and progression to adenocarcinoma as well as increased expression of EMT markers vimentin, sm-actin, col1a1, and Snail. We also show that expression of Rac1b in lung epithelial cells leads to spontaneous adenocarcinoma formation. These results demonstrate a direct linkage between induction of EMT and tumor progression, implicate Rac1b as a key mediator of these processes, and demonstrate that MMPs can directly stimulate all of these events.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2318.
Abstract 2325: Thrombospondin 1 inhibits angiogenesis in liver metastases but not lung metastases due to differential cleavage activity of ADAMTS1
Authors: Karl Daniel L. , Lee Yoon Jin , Koch Moritz , Torres-Collado Antoni X. , Fernando Namali T. , Rothrock Courtney , Kuruppu Darshini , Ryeom Sandra , Iruela-Arispe M. Luisa , Yoon Sam S. 
Published: February 2011

Abstract
Background: Metastases to any organ site require angiogenesis for tumor expansion. Tumor angiogenesis is restrained by a variety of endogenous inhibitors including thrombospondin 1 (TSP1). The principal anti-angiogenic activity of TSP1 resides in a domain containing 3 TSP1 repeats (3TSR), and TSP1 cleavage is regulated, in part, by the metalloproteinase ADAMTS1.
Methods and Results: Wild-type B16F10 melanoma cells formed increased liver metastases in Tsp1-null mice compared to controls but equivalent lung metastases in Tsp1-null mice and controls. Stable cell lines of B16F10, CT26 colon carcinoma, and RenCa renal carcinoma overexpressing full-length TSP1 or 3TSR were generated. Metastases from CT26 and RenCa cell lines over-expressing TSP1 were reduced in liver but not in lung. To determine why TSP1 blocked metastatic tumor growth in the liver but not the lung, we examined cleavage of recombinant TSP1 protein by liver and lung lysates and found that liver lysate cleaved TSP1 into its 3TSR domain much more efficiently that lung lysate. TSP1-mediated inhibition of CT26 lung metastases was restored when only the 3TSR domain was over-expressed rather than full-length TSP1. Liver lysate cleavage activity was significantly abrogated when ADAMTS1 activity was (1) neutralized using ADAMTS-1 antibody, (2) knocked down by lentiviral shRNA, or (3) absent in Adamts1-null liver lysate. Livers metastases generated from B16F10 cells over-expressing TSP1 in Adamts1-haploinsufficient mice demonstrated accelerated growth compared to growth in wild-type mice.
Conclusions: TSP1 inhibits the growth of liver metastases but not lung metastases secondary to differential cleavage of TSP1 into anti-angiogenic fragments by ADAMTS1. This study emphasizes the importance of host organ environment in the regulation of tumor angiogenesis.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2325.
Abstract 2326: Loss of prostate-specific antigen slows growth and alters the extracellular proteome of LNCaP human prostate cancer cells
Authors: Williams Simon A. , Jelinek Christine A. , Cotter Robert J. , Isaacs John T. , Denmeade Samuel R. 
Published: February 2011

Abstract
Prostate-specific antigen (PSA) is the most extensively used biomarker in cancer. There continues to be intense debate regarding the use of PSA in screening for prostate cancer (PCa) and how it may be used for optimal benefit. The role PSA plays in reproductive biology and PCa has been an area of ongoing interest. As a serine protease with novel substrate preferences, PSA continues to be secreted at high levels (mg/mL) even by the majority of advanced prostatic carcinomas. This protease has been shown to affect the growth or viability of a variety of cell types, including epithelial cells, osteoclasts, T-cells, and human PCa cell lines.
In this study, we stably reduced endogenous PSA gene expression using lentiviral short hairpin loop RNA (shRNA) technology in the LNCaP human PCa cell line. We then investigated any resulting changes to LNCaP growth rates in vitro and ex vivo. Acting on the hypothesis that any PSA-induced changes to LNCaP behavior are the result of the enzyme's extracellular activity, we used a high-throughput shot-gun mass spectrometry-based (MS) approach to analyze the in vitro extracellular LNCaP proteome in control and PSA-targeted shRNA populations.
Having demonstrated that our shRNA strategy targeted to PSA caused as much as a 90% reduction in PSA protein production compared to control cells, we next showed that in vitro doubling times are slowed from 2 days to 11 days. Subcutaneous tumors displayed an almost 50% reduction in take rate, with the final weights of those remaining only reaching 10% of controls after 8 weeks of growth.
Serum-free media conditioned for 24 hours by control or PSA-targeted LNCaP populations were then subjected to global semi-quantitative proteomics analysis using the high resolution LTQ-Orbitrap mass spectrometer (Thermo Electron, San Jose, CA). In one 200 minute LTQ-Orbitrap analysis, in conjunction with the Mascot Search algorithm (Matrix Science, Boston, MA), we were able to identify 1784 proteins in the LNCaP conditioned media. Of these, 686 were specific to the control populations, 527 were specific to the reduced PSA populations, and 571 were common to both.
These results demonstrate the utility of high-throughput proteomic strategies as an unbiased approach for the identification of candidate mechanisms behind novel observations in cancer biology.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2326.
Abstract 2328: Hyaluronan synthase expression in mammary tumor cells modulates tumor growth, angiogenesis and metastasis
Authors: Varney Michelle L. , Singh Rakesh 
Published: February 2011

Abstract
Breast cancer is the second most common cause of cancer death in women in the United States after lung cancer and is responsible for more than 40,000 deaths each year. At the time of diagnosis, the majority of breast cancer patients have developed regional lymph node or distant metastases. Many challenges exist in the current management of metastatic breast cancer as there are fewer recognized therapeutic strategies. Therefore, a better understanding of the molecular events in the metastatic process is critical. Several reports have described correlation of hyaluronan (HA) with initiation and progression of various types of epithelial cancers. The HA synthase (HAS) isoforms encode the enzymes that produce and deposit HA while the hyaluronidase (HYAL) genes code for enzymes that degrade HA and their expression is dysregulated in various tumors as a result of transcriptional and epigenetic changes that accompany progression. In this report, we examined the expression of HAS1, HAS2 and HAS3, HYAL1 and HYAL2 in mammary tumor cell with different metastatic potential (4T1, highly metastatic; Cl66, moderately metastatic; Cl66M2, low metastatic). We observed increased expression of HAS1, HAS2 and HAS3 as well as HAYL 1 and HAYL2 in aggressive mammary tumor cells. Next we stably knocked-down HAS2 and HAS3 expression in 4T1 cells using small hairpin mRNA (sh-RNA) vectors and analyzed cell proliferation, migration, tumor growth and metastasis. We observed inhibition of in vitro cell proliferation and migration in 4T1 cells knocked-down for HAS2 (4T1-HAS2sh) and HAS3 (4T1-HAS3sh) as compared to cells transfected with vector control (4T1-controlsh). Furthermore, we observed inhibition of in vivo tumor growth and spontaneous lymph node and lung metastases in animals implanted with 4T1-HAS2sh cells as compared to 4T1-controlsh. In addition, we observed inhibition of tumor cell proliferation and neovascularization, and increased apoptosis in 4T1-shHAS2 tumors as compared to 4T1-controlsh tumors. Together, these data demonstrate an important role of HAS2 in mammary tumor growth, angiogenesis, invasion, and metastasis.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2328.
Abstract 233: OTX2 copy number gain is a driver event in Shh-independent medulloblastomas
Authors: Wortham Matthew , Adamson David C. , Shi Qun , Northcott Paul A. , Di Chunhui , Duncan Christopher G. , Li Jianjun , McLendon Roger E. , Bigner Darell D. , Taylor Michael D. , Yan Hai 
Published: February 2011

Abstract
Medulloblastoma is the most common malignant brain tumor in children. With the exception of the Sonic Hedgehog (Shh) and Wnt pathways, the molecular events contributing to medulloblastoma tumorigenesis are poorly understood. In this study, we performed DNA copy number analysis upon a large cohort (n=201) of primary medulloblastomas to identify recurrent copy number events of these tumors. The most commonly gained region of the medulloblastoma genome (gained in 21% of tumors) contains the single gene OTX2, which encodes a developmental transcription factor involved in regionalization of the neural tube and specification of various CNS lineages. We found that OTX2 is also commonly overexpressed (74%, n=103) in these tumors. Molecular classification of medulloblastomas identified four distinct subtypes based on gene expression signature. OTX2 overexpression and copy number gain was limited to tumors not exhibiting a signature of Shh pathway activation. We found that OTX2 is necessary for intracranial xenograft formation by medulloblastoma cells and that its expression promotes xenograft tumor formation by immortalized primary cells. Finally, we determined that OTX2 regulates the medulloblastoma oncogene MYC. As a transcription factor, targeting OTX2 function with small molecules presents a challenge. However, retinoids can reduce OTX2 expression and inhibit medulloblastoma growth in vitro, and we have demonstrated that OTX2 silencing is required for this effect. In sum, these studies identify OTX2 as a common but targetable oncogene in Shh-independent medulloblastomas.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 233.
Abstract 2330: MMP-2 regulates Rac1- and Cdc42-mediated cell migration via integrin αVβ3/FAK in U87 and U251 glioblastoma cell lines
Authors: Chetty Chandramu , Lakka Sajani S. , Bhoopathi Praveen , Fassett Daniel , Klopfenstein Jeffrey D. , Dinh Dzung H. , Gujrati Meena , Rao Jasti S. 
Published: February 2011

Abstract
Gliomas, the most common form of brain tumors, are characterized by a capacity to invade through normal brain tissue. This infiltrative character is the hallmark of poor prognosis. A greater understanding of the molecular determinants that drive cell motility may lead to improved therapy. The molecules of the extracellular matrix are involved in organization of the cytoskeleton and activation of intracellular signaling that is required for the regulation of cell adhesion and migration. Here, we show that the downregulation of matrix metalloproteinase-2 (MMP-2; gelatinase A) using an adenoviral vector expressing siRNA (Ad-MMP-2-Si) inhibited cell migration in U87 and U251 glioblastoma cell lines as determined by spheroid migration and wound-healing assays. Transcriptional inactivation of MMP-2 altered interaction of MMP-2 and the integrin-αVβ3 as determined by immunoprecipitation and co-localization studies. In addition, downregulation of MMP-2 inhibited the complex formation of FAK, integrin-αVβ3 and 14-3-3ζ, which in turn decreased the activation of GTP-bound forms of Rac1 and Cdc42. Transfection of the cells with constitutively active Rac1 and Cdc42 reversed Ad-MMP-2-Si-blocked cell migration and gelatin degrading. Further, administration of recombinant human MMP-2 reversed MMP-2 siRNA-inhibited GTP-bound forms of Rac1 and Cdc42. Additionally, functionally blocking integrin-αVβ3 antibody inhibited GTP-bound forms of Rac1 and Cdc42, thereby revealing that the interaction of MMP-2 and integrin-αVβ3 plays a critical role in cell migration. In summary, our data demonstrate that the inhibition of MMP-2 inhibits integrin-αVβ3/FAK-mediated migration by reducing the GTP-bound forms of Rac1 and Cdc42 in U87 and U251 glioblastoma cell lines.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2330.
Abstract 2331: One of the first steps of metastasis is remodeling of the extracellular matrix microenvironment
Authors: Kenny Hilary A. , Leonhardt Payton , Ladanyi Andras , Gwin Katja , Lengyel Ernst 
Published: February 2011

Abstract
During metastasis tumor cells initiate processes that lead to the loss of normal tissue architecture and formation of the tumor microenvironment. The main site of metastasis in ovarian cancer (OvCa) is the omentum. Little is known about the initial changes in extra-cellular matrix (ECM) during early OvCa metastasis. A 3-dimensional (D) organotypic model of the omentum was used to investigate the remodeling of the ECMs during the initial steps of OvCa metastasis. Vitronectin and fibronectin increased when OvCa cells (SKOV3ip1 and Hey A8) were added to the 3D omental model, while collagen type I decreased. Vitronectin was produced by the cancer cells and stroma, while fibronectin was produced solely by cancer cells. Collagen type I decreases in stroma and increases in OvCa when co-cultured. Vitronectin, fibronectin and collagen type I are produced by primary human mesothelial cells and fibroblasts and are present in ascites. Two immunohistochemical studies with human tumors confirmed the above findings. First during early OvCa metastasis in humans, fibronectin is present in the stroma, while vitronectin and collagen type I are present in both cancer cells and the stroma. Second, ECM localization in 20 sets of primary and omental metastasis tumors from the same patients was performed. Fibronectin was absent in the primary tumor and present in the metastatic tumor stroma, while vitronectin was produced in cancer cells and stroma in primary and metastatic tumors. Additionally, a Reverse-Phase Protein Array was performed on primary versus omental metastasis tissue from 20 postmenopausal patients with FIGO Stage III/IV, high grade papillary-serous OvCa. Fibronectin was significantly increased, while vitronectin was significantly decreased in the omental metastasis vs. primary tumor, respectively. Additional experiments revealed changes in the tumor cell cytoskeleton in conjunction with increased expression of integrins (α5β1-and αvβ3-integrin) and proteases (uPA, uPAR, MMP-2 and MMP-9). Integrins and proteases were transiently knocked down using sequence-specific siRNA. Both α5β1-integrin and MMP-2, but not αvβ3-integrin and MMP-9, were found to be necessary for the remodeling of fibronectin. Taken together, these findings reveal the initial transformation of ECM in the normal omental architecture during early OvCa metastasis.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2331.
Abstract 2335: Role of heparanase in colitis associated cancer
Authors: Elkin Michael , Lerner Immanuel , Sherman Yoav , Hermano Esther , Vlodavsky Israel 
Published: February 2011

Abstract
Ulcerative colitis (UC) is a chronic inflammatory bowel disease that is closely associated with colon cancer. Here we report that heparanase enzyme acts as an important mediator of colitis-associated tumorigenesis. Heparanase is an only known mammalian enzyme that cleaves heparan sulfate, the major polysaccharide of the extracellular matrix, and plays multiple roles in inflammation and cancer progression. Applying histological specimens from UC patients and a mouse model of dextran sulfate sodium (DSS)-induced colitis, we found that heparanase is constantly overexpressed and activated during the course of the disease, both in the active and inactive phases of inflammation. Employing heparanase-overexpressing transgenic mice in the model of colitis-associated cancer, induced by carcinogen azoxymethane followed by repeated DSS administration, we demonstrated that heparanase overexpression markedly increased the incidence and severity of colitis-associated colonic tumors, enabling faster tumor take, angiogenic switch and enhanced tumor progression. Notably, DSS-induced colitis alone (without azoxymethane pretreatment) lead to formation of colonic tumors in heparanase-transgenic, but not wild type mice, positioning heparanase as important physiological determinant in inflammation-driven colon carcinoma, replacing the need for carcinogen. Investigating molecular mechanisms underlying heparanase induction in colitis, we found that macrophage-derived cytokines (i.e., TNFalfa) are responsible for continuous overexpression of heparanase by chronically-inflamed colonic epithelium. Moreover, our results suggest the occurrence of heparanase-driven vicious cycle that power colitis and associated tumorigenesis: heparanase activity in inflamed colon, acting synergistically with the local cytokine milieu, stimulates macrophage activation, and the activated macrophages secrete TNFalfa which stimulate further production of heparanase by colonic epithelium. In addition, activated macrophages secrete cathepsin L - a cysteine protease responsible for proteolytic activation of latent heparanase enzyme. Altogether, our results identify heparanase as a key factor in pathogenesis of colitis-associated cancer and attest macrophages as both heparanase regulators and cellular target for heparanase action.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2335.