bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 426: Sox2 expression in breast cancer stem cells: Possible mechanisms
Authors: Esnaola Olatz Leis , Eguiara Arrate , Jesus Alberdi Maria , Kepa Elorriaga , Rezola Ricardo , Martin Angel G.
Published: August 2012

The cancer stem cell (CSC) model does not imply that tumours are generated from transformed tissue stem cells. The target of transformation could be a tissue stem cell, a progenitor cell, or a differentiated cell that acquires self-renewal ability. The observation that induced pluripotency reprogramming and cancer are related has lead to the speculation that CSCs may arise through a reprogramming-like mechanism. Expression of pluripotency genes (Oct4, Nanog and Sox2) was tested in breast tumours by immunohistochemistry and it was found that Sox2 is expressed in early stage breast tumors. Mammosphere formation in culture was used to reveal stem cell properties, where expression of Sox2, but not Oct4 or Nanog, was induced. Over-expression of Sox2 increased mammosphere formation, effect dependent on continuous Sox2 expression; furthermore, Sox2 knockdown prevented mammosphere formation and delayed tumour formation in xenograft tumour initiation models. These findings suggest that reactivation of Sox2 represents an early step in breast tumour initiation, explaining tumour heterogeneity by placing the tumour-initiating event in any cell along the axis of mammary differentiation. Now we present evidence on what breast cancer specific mechanisms may control Sox2 expression activation.

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 426. doi:1538-7445.AM2012-426
Abstract 4263: Dynamic phenotype switching regulated by epigenetic marks along melanoma genesis
Authors: Morais Alice S. , Molognoni Fernanda , Jasiulionis Miriam Galvonas
Published: August 2012

Melanoma is the most aggressive form of skin cancer and its incidence is increasing worldwide. Although melanoma is highly curable when early diagnosed, the metastatic melanoma detains the worst prognosis and remains one of the most resistant cancers to treatment. In this light, continuous efforts are made to better understand the pathogenesis of this disease. It has been strongly suggested that aberrant epigenetic events, occurred in specific steps, are important to the establishment and progression of tumor genesis as the occurrence of point genetic mutations. Based on a murine model of malignant transformation, the aim of our group has been identify and understand the effective participation of epigenetic mechanisms in the generation of a transformed phenotype. The study model of melanoma genesis was established in vitro by submitting non-tumorigenic melanocytes (murine melan-a cell line) to sequential cycles of anchorage blockade, proposing that microenvironment interference may lead to intracellular alterations with important gene expression impact. Our cell lines represent distinct phases of melanoma genesis (melan-a melanocytes, 4C pre-malignant melanocytes, 4C11- non-metastatic and 4C11+ metastatic melanoma) and, on an overview, it was observed clearly morphological differences, mainly in intermediate stages of progression, suggesting a transient change from epithelial to mesenchymal phenotype (from melan-a to 4C and 4C11- cell lines) along malignant transformation. This transitory modification was accompanied by a switch in the EMT markers expression, like Snail1 and your targets, β-catenin, E-cadherin and N-cadherin. In parallel, Chd1 (chromatin remodeling factor), Nanog (pluripotency factor) and Jarid1b (histone demethylase) are highly expressed in these intermediate phases (4C and 4C11-), characterizing an open chromatin configuration. Interestingly, expression of most of these genes appear to be controlled by epigenetic mechanisms, both DNA methylation and chromatin modification. We hypothesized that during melanocyte malignant progression associated with sustained stress, an opened chromatin occurrence would facilitate cells to undergo changes in gene expression which allow cell adaptation to new environment and all these alterations are orchestrated by epigenetic events. Supported by FAPESP.

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 4263. doi:1538-7445.AM2012-4263
Abstract 4265: Human prostate mesenchymal stem cells in prostate cancer: Mechanisms of TGF-β1 promoted myofibroblast/CAF differentiation
Authors: Kim Woosook , Barron David , Ressler Steven , Rowley David
Published: August 2012

Reactive stroma in prostate cancer is typified by the co-evolution of myofibroblasts and carcinoma-associated fibroblasts (CAFs), yet the origin and biology of myofibroblast stem/progenitor cells are not known. TGF-β1 is overexpressed in prostate cancer cells and affects myofibroblast differentiation, a key step in formation of a tumor-promoting reactive stroma. However, specific mechanisms of how TGF-β1 regulates recruitment, activation and differentiation of myofibroblast stem/progenitor cells are poorly understood. Human prostate mesenchymal stem cell (hpMSC) lines were initiated from organ cultures of normal human prostate gland and characterized by a novel 3D co-culture model. Differentially engineered LNCaP cells to overexpress active TGF-β1 were cultured as organoids on CM-inserts and hpMSCs were co-cultured with engineered LNCaP cells either in direct contact or on laminin-coated coverslips in the bottom chamber. 3D organoids grown in serum-free media for 72 hours were analyzed by IHC, ELISA and qRT-PCR. In addition, RNAi gene knockdown experiments were performed in hpMSC to identify key transcription factors involved in myofibroblast/CAF differentiation. hpMSCs were CD44+/CD90+ and showed characteristics and gene expression similar to human mesenchymal stem cells. In the 3D model, LNCaP cells and hpMSCs self-organized into a free-floating organoid. The organoids exhibited a periphery of LNCaP cells and a core of reactive stroma-appearing cells. Significantly, LNCaP cells induced myofibroblast differentiation of hpMSC and this was promoted by LNCaP expression of active TGF-β1. Gene expression analysis identified the RUNX1 and ID1 transcription factors as upregulated in hpMSC by TGF-β1. Knockdown of RUNX1 and ID1 are being used to assess the role and mechanisms of how these transcription factors regulate myofibroblast differentiation. Together, these data suggest that the genesis and co-evolution of reactive stroma in prostate cancer results from activation and differentiation of CD44+/CD90+ endogenous hpMSC via upregulation of specific transcription factors by TGF-β1. Defining key mechanisms that recruit, activate and differentiate the origin of myofibroblasts/CAFs could provide clues to develop new strategies to target the microenvironment niche.

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 4265. doi:1538-7445.AM2012-4265
Abstract 4266: Identification of gene expression profiles associated with different types of breast adipose and their relationship to tumorigenesis
Authors: Field Lori A. , Deyarmin Brenda , van Laar Ryan , Shriver Craig , Ellsworth Rachel E.
Published: August 2012

Background: Research over the past decade has shown the importance of the stroma in tumorigenesis, however, having long been thought to function only as an inert energy storage depot, the role of adipose tissue in tumorigenesis has been largely ignored. Improved understanding of the role of adipose in tumorigenesis is crucial given the increasing rates of obesity and the use of autologous fat transfer in breast reconstruction. Methods: Adipose, adjacent to and distant from invasive breast tumors, was laser microdissected from 20 post-menopausal women, and from 20 post-menopausal women with non-malignant breast disease. Gene expression data were generated using U133 2.0 microarrays. After quality control and visualization steps, the data were analyzed to identify significant patterns of differential expression between adipose classes, at the individual gene and molecular pathway level. Results: Pathway analysis revealed that immune response differs between non-malignant, distant and tumor adjacent adipose; this response is seen as a gradient with the largest response closest to the tumor. Gene expression differed significantly in adipose from invasive compared to non-malignant breasts with FCGR2A, FOLR2, LGMN, MARCO and NLRP3 expressed at significantly higher levels and HLA-DQB1 and HLA-DQA1 at significantly lower levels in adipose from invasive breasts. Within the invasive breasts, MMP9, PLA2G7, RRM2 and SPP1 were expressed at >3-fold higher levels in adjacent compared to distant adipose. Conclusions: Gene expression levels differ in breast adipose, depending on presence of or proximity to tumor cells. Adipose adjacent to the tumor demonstrated the largest immune response; this response may reflect a reaction to surgical insult from the original biopsy; however, response to surgical injury has been associated with increased ability to metastasize. In addition, within breasts with invasive breast cancer, genes involved in cellular proliferation, degradation of the extracellular matrix and angiogenesis were expressed at higher levels in adjacent compared to distant adipose. Together, these data suggest that adipose is not an inert component of the breast microenvironment but plays an active role in tumorigenesis.

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 4266. doi:1538-7445.AM2012-4266
Abstract 4273: C-kit expression promotes prostate cancer cell migration and invasion through Brca2 downregulation
Authors: Zhe Xiaoning , Azevedo Marcelo Quintanihla , Cher Michael L. , Kim Hyeong-Reh C. , Bonfil R. Daniel
Published: August 2012

In many human cancers, expression or activity of the receptor tyrosine kinase (RTK) c-kit is often associated with increased malignancy. In prostate cancer (PCa), we reported an association between expression of c-kit and clinical progression, with the highest expression seen in castrate-resistant metastatic bone specimens. We also found de novo c-kit expression in experimental intraosseous tumors formed by otherwise c-kit negative PCa cells. However, the biological consequences of c-kit expression and activation in PCa cells remain unknown. Here, we show that c-kit overexpression in PC3 and C4-2B PCa cells significantly enhances their migratory and invasive ability in vitro. Consistent with this result, we found that expression and activation of c-kit in PCa cells decreased the expression of E-cadherin and increased the expression of vimentin, suggesting an epithelial mesenchymal transition-like phenomenon. Furthermore, activation by c-kit ligand in PC3 and C4-2B cells transfected with c-kit lead to phosphorylation of Akt. This contributes to the enhanced invasiveness of c-kit-expressing PCa cells, as demonstrated by an inhibitory effect by PI3K/Akt inhibitors LY294002 and Wortmannin. In an attempt to identify genes differentially expressed in c-kit-expressing and -non-expressing PCa cells, we used a microarray containing 84 genes, representing growth factor receptors, transcription factors, cell cycle, and DNA repair genes. The analysis of the array demonstrated a consistent down-regulation of Brca2 in both c-kit-expressing PC3 and C4-2B cells, further validated by qRT-PCR and immunoblotting. Re-introduction of Brca2 into c-kit-expressing PCa cells suppressed c-kit-enhanced invasiveness to levels similar to those shown by c-kit-non-expressing cells, and led to reduced phosphorylation of Akt. Our results provide evidence that c-kit expression in PCa cells, an event which is induced upon interaction with the bone microenvironment, promotes tumor migration and invasion through an Akt-dependent mechanism regulated by Brca2 down-regulation. The identification of this novel signaling axis and its importance in PCa migration and invasion reveal potential therapeutic targets for regulating the expansion of PCa metastatic lesions in bone.

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 4273. doi:1538-7445.AM2012-4273
Abstract 4275: PLA2 activities in human epithelial ovarian cancer ascites
Authors: Xu Yan , Cai Qingchun , Zhao Zhenwen , Antalis Caryl J. , Yan Libo , Hamed Ali H. , Stehman Frederick B. , Schilder Jeanne M. , Priore Giuseppe Del
Published: August 2012

Ascites production is characteristic of late stage human epithelial ovarian cancer (EOC) and it correlates with tumor spread clinically. However, the role of this microenvironment in cancer cells and the mechanisms by which ascites promotes tumor development are not well understood. In recent years, phospholipase A2 (PLA2) enzymes have been identified as cancer therapeutic targets focusing mainly on secreted PLA2s (sPLA2s). In this work, we optimized and validated the quantitative analytic methods to measure PLA2 activities in human EOC ascites and tissues. We found, for the first time, that both cytosolic PLA2 (cPLA2) and calcium-independent PLA2 (iPLA2), but not sPLA2 and autotaxin (ATX), activities (not their expression levels) in human EOC tissues and ascites (the tumor microenvironment) were significantly elevated. In addition, while cell-free (S1) and vesicle-free (S4) human EOC ascites had potent promoting activities in proliferation, migration, and invasion of human EOC cells, the PLA2 activities were involved and account for a significant portion of these activities. Moreover, in vivo studies demonstrated that methyl arachidonyl fluorophosphonate (MAFP, a dual inhibitor of cPLA2 and iPLA2), was highly effective in inhibiting EOC tumorigenesis/metastasis in xenograft models, supporting PLA2 activities as new targets for EOC. LPA, an enzymatic product of ATX and PLA2 enzymes, mediates a significant part of the cellular effects of ascites as evidenced by 1) LPA is produced in cell-free ascites; 2) LPA production and their sensitivities to inhibitors correlate well with the cellular effects in ascites; and 3) the cellular activities were sensitive to LPAR inhibitor and siRNA against LPARs. While cPLA2 and iPLA2 are cytosolic enzymes, our findings indicate that they are associated with cell- and microvesicle-free ascites. In summary, our work implies the potential marker and therapeutic values of PLA2 activity in ovarian cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4275. doi:1538-7445.AM2012-4275
Abstract 4281: Adaptive post-translational regulation of the thiamine transporter THTR1 in breast cancer cells during hypoxic stress
Authors: Zastre Jason , Sweet Becky , Govindarajan Rajgopal
Published: August 2012

Purpose: The cellular metabolic re-programming within hypoxic tumor microenvironments involves adaptations that alter the cellular dependence for glycolysis and the pentose phosphate pathway. However, enzymatic activity within these pathways requires an adequate supply and cellular pool of enzyme cofactors. In particular, thiamine is an essential cofactor within key metabolic pathways that are responsible for energy production and anabolic precursor synthesis. Previously, we have reported on the hypoxia-mediated transcriptional regulation of the thiamine transporters within breast cancer cells. Therefore, the purpose of this study was to further our understanding of hypoxia-mediated regulation of thiamine transporters, by examining the intracellular localization and plasma membrane expression of THTR1 during hypoxic stress. Methods: Immunofluorescence was employed to visualize the intracellular localization of THTR1 (SLC19A2) within the non-transformed breast epithelial cell line, MCF10A and breast cancer cells, BT20 and BT474 after 1, 3 and 7 days of 1% O2 exposure. Cell surface biotinlyation assays were utilized to assess changes in the plasma membrane expression of THTR1 after hypoxia exposure. In addition, total THTR1 expression was determined using Western blotting of whole cell lysates and qRT-PCR. Results: The cellular distribution of THTR1 was predominantly localized in the plasma membrane for the non-transformed MCF10A cells, but was predominantly intracellular in the breast cancer cells, BT20 and BT474. No change in total mRNA or cellular THTR1 protein expression was found after hypoxic exposure. However, THTR1 exhibited a time dependent increase in plasma membrane localization after 1% O2 exposure. This observation was confirmed with an increase in THTR1 plasma membrane expression using cell surface biotinylation pull down assays. Conclusions: We conclude that hypoxic stress induces the intracellular trafficking of the thiamine transporter THTR1 to the plasma membrane. These results suggest that post-translational modification of THTR1 during hypoxic exposure may be an essential adaptive cellular response to increase intracellular supply of thiamine to support glycolytic metabolism.

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 4281. doi:1538-7445.AM2012-4281
Abstract 4282: Analysis of epithelial and stromal cell networks in prostate cancer by gene expression profiles
Authors: Ashida Shingo , Kawada Chiaki , Inoue Keiji , Shuin Taro
Published: August 2012

Recent studies have highlighted tumor microenvironment as important in carcinogenesis and progression. Especially in prostate cancer (PC), it has been suggested that tumor microenvironment plays an important role in progression, acquisition of androgen independence, and distant metastasis. However, little is known about the genetic basis of human PC microenvironment. The prognosis of PC is related to invasion and metastasis. Epithelial-to-mesenchymal transition (EMT) has gained considerable attention as a conceptual paradigm to explain invasive and metastatic behavior during cancer progression. EMT is a normal physiologic process by which cells of epithelial origin convert into cells with mesenchymal characteristics. It has been proposed that EMT is induced by cancer cells during metastatic dissemination from a primary organ to secondary sites, but how EMT occurs during PC invasion and metastasis remains uncertain. To clarify the mechanism of PC progression and metastasis, we investigated cross-interaction of PC epithelial cells and stromal cells by analyzing genome-wide gene expression profiles. We hypothesized that PC cells could affect on stromal cells to change their characteristics into so-called cancer-associated fibroblasts (CAFs), which might contribute to cancer invasion and metastasis. Likewise, CAFs could affect on surrounding normal epithelial cells to change their characteristics into PC cells. We first analyzed three of genome-wide gene expression profiles; normal human prostate stromal cells (PrSC) co-cultured with human prostate cancer cells (LNCaP), LNCaP co-cultured with PrSC, and human prostate epithelial cells (PrEC) co-cultured with cancer-associated PrSC which is PrSC previously co-cultured with LNCaP. Before microarray analysis, we confirmed the overexpression of alpha-smooth muscle actin in PrSC co-cultured with LNCaP, which means the transition from normal stromal cells to CAFs. We then analyzed networks among PC cells, stromal cells, and surrounding normal epithelial cells by analyzing gene expression profiles and validated our data using real-time PCR, immunohistochemistry, and bioinformatics. These data provide clues to the molecular mechanisms underlying PC invasion and metastasis, and suggest candidate genes the products of which might serve as molecular targets for the treatment of PC.

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 4282. doi:1538-7445.AM2012-4282
Abstract 4284: Prognosis of prostate cancer using gene expression changes in stroma
Authors: Jia Zhenyu , Rahmatpanah Farahnaz , Chen Xin , Lernhardt Waldemar , Wang Yipeng , McClelland Michael , Mercola Dan
Published: August 2012

Enormous efforts have been invested in the development of biomarkers for prognosis of prostate cancer in order to address urgent questions regarding overtreatment by radical methods. Nevertheless, few accepted and clinically useful biomarkers have been developed. A possible barrier to biomarker discovery may be accumulated genetic alterations in tumor cells resulting in polyclonal/multifocal prostate tumors as well as cell-type heterogeneity of prostate cancer between patients. Tumor-adjacent stroma (tumor microenvironment) is less affected by genetic alteration and might therefore yield more consistent biomarkers for clinical tests. To this end we compared gene expression profiles in stroma near tumor from high-risk patients that chemically relapsed shortly after prostatectomy (< 1 year), and low-risk patients either relapsed later than 4 years after surgery or who did not relapse and had at least 4 years’ follow-up data available. We identified 131 differentially expressed genes in these two categories. We also identified another set of 115 genes of which the expression levels are significantly correlated with time-to-relapse for the relapsed patients. Using the 19 genes that overlapped between the two gene lists, we developed a PAM-based classifier by training on samples containing stroma near tumor: 9 high-risk patient samples and 9 low-risk patient samples. We then tested the classifier on 47 independent samples, including 38 samples containing stroma near tumor and 9 tumor-bearing samples containing at least 90% stroma near tumor. The classifier predicted the risk status of patients with an average accuracy of 87%. These results indicate that the prostate cancer microenvironment exhibits reproducible changes useful for predicting outcomes for patients.

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 4284. doi:1538-7445.AM2012-4284
Abstract 4287: M13-stabilized single-walled carbon nanotubes as nanoprobes for second near-infrared window fluorescent imaging of targeted tumors
Authors: Ghosh Debadyuti , Yi Hyunjung , Qi Jifa , Belcher Angela M.
Published: August 2012

Second near-infrared (NIR) window light (950-1,400 nm) is attractive for in vivo fluorescence imaging due to its deep penetration depth in tissues and low tissue autofluorescence. Here we show genetically engineered multifunctional M13 phage can assemble fluorescent single-walled carbon nanotubes (SWNTs) and ligands for targeted fluorescence imaging of tumors. M13-SWNT probe is detectable in deep tissues even at a low dosage of 2 μg/mL and up to 2.5 cm in tissue-like phantoms. Moreover, targeted probes show specific and four-fold improved uptake in prostate specific membrane antigen positive prostate tumors compared to control non-targeted probes. This M13 phage-based second NIR window fluorescence imaging probe has great potential for specific detection and therapy monitoring of hard-to-detect areas.

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 4287. doi:1538-7445.AM2012-4287
Abstract 4288: in vivo Imaging of early inflammation response in bacterial infection
Authors: Papineni Rao V. , Orton Sean , McLaughlin William , Bianchi Damian
Published: August 2012

Staphylococcus aureus (S. aureus) causes significant morbidity and mortality worldwide and a prime cause in hospital infections. Staphylococcus aureus bactereremia is prevalent in neutropenic cancer patients, and malignancies form a sizeable risk factor for methycillin-resistant S. aureus (MRSA) infections. Targeting the virulence products is a promising approach for developing novel therapeutics. A detailed understanding of the virulence factors and the resultant immune response is quite essential for such development. Here, we established an athymic mice model to assess the initial immune response to S.aureus inoculation. As the polymorphonuclear neutrophils(PMN)and macrophages are a part of the early response, determination of its myeloperoxidase (MPO) activity in vivo is established. MPO is an inflammatory heme protein and utilizes hydrogen peroxide in the process of reactive oxygen species generation. 24 hrs after the intra muscular injection of the S.aureus bacterial lysate, the MPO activity was detected by i.p injection of luminal in mice. The blue luminescence resulting from the MPO activity was imaged and the luminescence images were overlaid on planar X-ray images for anatomical co-registration. The results show a robust MPO activity in the mouse bladder. This increase in MPO activity as a result of neutrophil activation at the bladder region was further confirmed using non-invasive X-ray contrast imaging of the bladder and co-registering the luminescence and the X-ray density signals at the bladder. The initial response shown here has similarities with the mechanism suggested recently for myobacterium bovis bacillus Calmette-Guerin (BCG) treatment of bladder cancer. Bacterial components, its structures that are involved in eliciting the robust PMN infiltration in bladder will be very valuable in the developing better bladder cancer anti-tumor treatments.

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 4288. doi:1538-7445.AM2012-4288
Abstract 4295: Multifunctional nanoconstructs for tumor visualization using contrast enhanced MRI
Authors: Ananta Jeyarama , Sethi Richa , Gizzatov Ayrat , Acharya Ghanashyam , Liu Xuewu , Karmonik Christof , Wilson Lon , Decuzzi Paolo
Published: August 2012

New multifunctional nanoconstructs using mesoporous Si particles (SiMPs) and polymeric hydrogel particles (HG) are synthesized with superior MRI efficacy and favorable pharmacokinetic properties. Clinically relevant Gd3+-based contrast agents (CAs) for magnetic resonance imaging (MRI), namely [Gd (DTPA)]2−, [Gd (DOTA)]1- and superparamagnetic iron oxide (SPIO) nanoparticles, were either i) encapsulated within the mesoporous structure of the SiMPs or ii) covalently attached to SiMPs and HGs. The size (from 400 to 2000 nm) and shape (discoidal, cylindrical, etc.) of the nanoconstructs are accurately tailored during the fabrication process to control the in vivo biodistribution. In tumor bearing mouse model, discoidal particles with a characteristic size of 1000 x 400 nm were found to accumulate at the tumor site more than other particles. The incorporation of clinically used, FDA approved CAs into the mesoporous structure of the SiMPs led to magnetic nanoconstructs exhibiting much higher relaxivities as compared to free CAs in solution. In particular, the relaxivity for [Gd (DTPA)]2− and [Gd (DOTA)]−1 loaded SiMPs was measured to be ∼ 25 mM−1s−1, which is more than 6 times larger than the r1 obtained for free CAs (∼ 4 mM−1s−1). The pore size played a dominant role in that the relaxivity was observed to grow with a reduction in pore diameter: r1 ∼ 24 mM−1s−1 for small pore SiMPs (5-10 nm); and r1 ∼ 10 mM−1s−1 for huge pore SiMPs (30-40 nm). CAs covalently attached to SiMPs and HGs, exhibited no such dependence on pore sizes but provided comparable enhancement in r1. For SPIOs encapsulated in mesoporous SiMPs, a much larger enhancement in relaxivity was observed with r2 ∼ 220 mM−1s−1 for the resulting nanoconstructs against r2 ∼ 11.2 mM−1s−1 for free SPIOs. These results suggest that geometrical confinement into mesopores is a general strategy for enhancing the performance of both T1 and T2 MRI CAs. Intravenous injection of SPIO-loaded SiMPs in melanoma bearing mice decreased the contrast (T2-weigthed relaxation), confirming the high level of accumulation of these nanoconstructs at the tumor site. For the enhanced relaxivity and superior localization of imaging agents at the target site, the proposed nanoconstructs provide an ideal platform for early cancer detection by MRI. In addition, the easily functionalizable surface of these nanoconstructs render them the ability to perform cellular and molecular imaging using clinical MRI scanners.

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 4295. doi:1538-7445.AM2012-4295
Abstract 4301: Shear stress induces Rac1/Rab5 circular ruffling/endosomes at the apical surface of metastatic esophageal tumor cells enhancing spreading and motility responses
Authors: Lawler Karen , Kijanka Gregor , Sullivan Gerald O’ , Long Aideen , Kenny Dermot
Published: August 2012

A coordinated mode of motility is required for dissemination and invasion of esophageal metastases through the vasculature. This motility is largely driven by the activation of GTPases Rac1 and Rab5 which regulate 2 and 3-dimensional motility respectively; however, little is known about the localization and activation of these GTPases under hydrodynamic flow. In this study, the effect of Rac1 activation on tumor motility was investigated in a controlled microfluidic chip that simulates venous flow conditions. A metastatic esophageal cell line derived from the ascites of a male patient with squamous cell cancer of the esophagus (OC-1), was transiently transfected with cDNA encoding active (L61), dominant negative (N17) and wild type (WT) Rac1 fused to GFP to enable visual localization of Rac1 in real time under static and fluid flow conditions. Transfected OC-1 cells were allowed to adhere to fibronectin (Fn) for 30 minutes under static conditions or allowed to adhere to Fn for 5 minutes followed by exposure to a continuous venous shear rate of 200 s-1 for 25 minutes. Cell motility and Rac1 localization was monitored over a 30-minute period followed by cell fixation and co-staining with a polyclonal antibody directed against Rab5 to visualize endosomal trafficking within the cells. The results of our study show that the over-expression of constitutively active Rac1 enhances circular ruffling, pseudopodia formation and motility in OC-1 cells under static conditions when compared to N17 and WT Rac1. Moreover, this activation response in L61-transfected cells is significantly increased in the presence of venous shear rates, (p<0.0013) and completely inhibited in cells expressing the N17 active mutant which display rounded quiescent morphology states. Co-localization studies confirmed that both Rac1 and Rab5 GTPases are recruited to distinct populations of endosomes containing actin at the apical membrane of OC-1 cells under shear, measuring between 0.6 and 1.5 μm. These results suggest that Rab5/Rac1 circular ruffling/endosomal recruitment at the apical surface is an important adaptive response to enhance motility under fluid flow conditions. Moreover, this study may offer insight into mechano-receptor signaling and how metastatic cells adapt and disseminate in circulation.

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 4301. doi:1538-7445.AM2012-4301
Abstract 4303: A high-throughput cell invasion assay combined with reverse phase protein microarrays for rational development of drug combination strategies targeting tumor invasion
Authors: Dawson John C. , Carragher Neil O. , Fronczak Jennifer , Hulkower Keren
Published: August 2012

Tumor invasion and metastasis is responsible for 90% of all deaths in cancer patients that are non-responsive to surgical procedures or initial therapeutic treatments. Clinical studies of inhibitors targeted against specific signalling pathways associated with tumor invasion frequently fail due to alternate signalling pathways that support persistent invasion through compensatory mechanisms. The aim of this study was to apply an image-based multi-well 3-dimensional (3D) invasion assay platform (OrisTM Pro Cell Invasion Assay, Platypus Technologies LLC) incorporating distinct cancer cell types and extra cellular matrix (ECM) substrates in parallel with an ultra-sensitive and high-throughput reverse phase protein microarray (RPPMA) platform (Zeptosens) to identify and validate drugs and their combinations targeting distinct modes of tumor invasion. At sub-micromolar concentrations the results show that a matrix metalloproteinase inhibitor (GM6001) and panel of tyrosine kinase inhibitors suppress the 3D invasion of two breast cancer cell lines (MDA-MB-231 and HCC1569) into a basement membrane matrix. The image based invasion assays further revealed an altered invasive morphology in response to distinct compound treatments, with cells losing their typical elongated mesenchymal phenotype and adopting a more ameoboid shape. These results suggest that inhibitor treatment initiates alternative invasive mechanisms. An RPPMA platform has been used to identify post-translational signalling pathways that drive adaptive responses to monotherapy and to guide selection of drug combination partners. Further testing of drug combinations in the OrisTM 3D invasion assay format shall enable quantification of additive and synergistic drug combination responses upon tumor invasion in parallel with cell viability endpoints. These studies provide a robust model by which to evaluate different combinations of drugs targeting tumor invasion that will help prioritize clinical development strategies. ACKNOWLEDGEMENT: This work was partially supported by NIH Grant 2R44GM090386 to Platypus Technologies.

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 4303. doi:1538-7445.AM2012-4303
Abstract 4308: ZEB1 mediates invasion and chemoresistance of glioblastoma
Authors: Siebzehnrubl Florian , Silver Daniel , Tugertimur Bugra , Deleyrolle Loic , Suslov Oleg , Siebzehnrubl Dorit , Sarkisian Matthew , Kuepper Marius , Yachnis Antony , Brabletz Simone , Brabletz Thomas , Reynolds Brent , Steindler Dennis
Published: August 2012

Despite intense efforts in basic research and clinical medicine, glioblastoma (GBM) remains one of the most lethal types of cancer. In particular, tumor recurrence after surgical resection, aggressive chemotherapy, and targeted radiation remains an insurmountable obstacle. Recurrence has been attributed to residual cancer cells that re-initiate tumor growth after primary clinical intervention. Here, we provide new evidence that a subpopulation of invasive and chemoresistant cancer cells is maintained by the transcription factor ZEB1 (zinc finger E-box binding homeobox 1). ZEB1 is preferentially expressed in invasive glioblastoma cells, and its knockdown results in a dramatic reduction of tumor invasion as well as increased sensitivity to the chemotherapeutic agent Temozolomide (Temodar®, TMZ) in vitro and in vivo. We find that ZEB1 indirectly controls expression of the chemoresistance-mediating enzyme MGMT (O-6-Methylguanine DNA Methyltransferase), as well as cell-cell adhesion pathways, thus linking chemoresistance and brain tumor invasion. Moreover, ZEB1 expression in glioblastoma patients correlates with tumor grade and survival. These results indicate that invasive glioblastoma cells are particularly sheltered from current therapeutic approaches, rendering them likely candidates for tumor recurrence. This offers a potential novel model for GBM recurrence, and a potential new therapeutic target.

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 4308. doi:1538-7445.AM2012-4308
Abstract 4309: DYRK2 regulates cancer invasiveness via Snail/E-cadherin pathway
Authors: Mimoto Rei , Taira Naoe , Yoshida Kiyotugu , Miki Yoshio
Published: August 2012

Epithelial-mesenchymal transition (EMT) is characterized by the loss of cellular adhesion molecule E-cadherin, and plays a fundamental role during early steps of invasion and metastasis. An important regulator of E-cadherin expression is Snail, a zinc-finger transcriptional repressor. Snail is phosphorylated by GSK3-α and then degraded by α-TrCP-mediated ubiquitination. Here we describe another kinase, DYRK2, acts as a priming kinase for snail whose phosphorylation is required for the subsequent GSK3&gamma phosphorylation and proteasomal degradation. Inhibition of DYRK2 expression by siRNA results in up-regulation of Snail and down-regulation of E-cadherin. The expression of fibroblast mrakers, vimentin and fibronectin, emerged in these cells. Furthermore, the invasiveness of MCF7 cells was increased by stable DYRK2 silencing by shRNA. Tumors expressing DYRK2-shRNA robustly formed metastases in nude mice bones, while those expressing control-shRNA little if any. In human breast cancer tissues, DYRK2 exhibits an inverse correlation with the expression of Snail. Conversely, low level expression of DYRK2 is associated with down regulation of E-cadherin. The patiens with tumors expressed low DYRK2 showed significantly poor prognosis and short disease-free survival. These results demonstrate that DYRK2 regulates cancer invasiveness and metastasis via Snail/E-cadherin pathway in human breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4309. doi:1538-7445.AM2012-4309
Abstract 431: ErbB4 is a novel driver of metastasis and anoikis resistance in Ewing's sarcoma
Authors: Mendoza-Naranjo Ariadna , Wai Daniel H. , Farrar Jason E. , Zhu Qingsong , Mistry Priti , Lazic Nikola , Ayala Fernanda Rocha Rojas , Cunha Isabela Werneck da , Arceci Robert J. , Soares Fernando A. , Triche Timothy J. , Strauss Sandra J. , Sorensen Poul Hb
Published: August 2012

Most Ewing family tumor (EFT) related deaths occur as a consequence of metastatic disease. Using high-throughput Affymetrix arrays, and matched primary and metastatic tumor-derived cell line pairs, we have identified ERBB4, a member of the epidermal growth factor receptor (EGFR) family, as a novel driver of metastasis and anoikis resistance in EFTs. Gene expression profiling, mRNA analysis, and immunoblotting revealed a 2 to 4-fold increase in ERBB4 expression in metastatic compared to primary EFT cell lines. SNP profiling failed to show copy number aberrations to explain the increased ErbB4 expression in metastatic cell lines. However, epigenetic mechanisms were found to potentially regulate ERBB4 expression in the paired CHLA-9 primary and in the metastatic/chemoresistant CHLA-10 cell line derived from the same patient. Treatment with 5-aza-2α-deoxycytidine enhanced ErbB4 in CHLA-9 cells, but reduced its expression in CHLA-10, suggesting a potential role for DNA methylation in controlling ERBB4 expression in EFTs. Enhanced protein expression and ErbB4 tyrosine kinase activation were clearly identified in metastatic versus primary cells grown under anchorage independent conditions (as multicellular spheroids), which mimic micrometastases. We next evaluated the clinical relevance of these data using biopsies from EFT patients. We found a direct correlation between ErbB4 expression and reduced disease-free survival (p<0.05), and identified statistically higher ErbB4 expression (p<0.05) in metastatic vs. primary biopsies (80% vs. 56%, respectively). ErbB4 gene knockdown or treatment with the FDA-approved pan-ErbB inhibitor Lapatinib reduced proliferation, blocked cell migration and tumor invasion, and sensitized metastatic/chemoresistant cell lines to EFT standard of care chemotherapeutic drugs. Taken together, our findings identify ErbB4 as a novel driver of metastasis in EFTs.

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 431. doi:1538-7445.AM2012-431
Abstract 4311: EphB2 receptor controls proliferation/migration dichotomy of glioblastoma by interacting with focal adhesion kinase
Authors: Wang Shervin D. , Rath Prakash , Lal Bachchu , Richard Jean-Philippe , Li Yunqing Li , Goodwin C. Rory , Laterra John , Xia Shuli
Published: August 2012

Glioblastoma multiforme (GBM) are the most frequent and aggressive primary brain tumors in adults. Uncontrolled proliferation and abnormal cell migration are two prominent spatially and temporally disassociated characteristics of GBMs. In this study, we investigated the role of the receptor tyrosine kinase EphB2 in controlling the proliferation/migration dichotomy of GBM. We studied EphB2 gain-of-function and loss-of function in glioblastoma-derived stem-like neurospheres (GBM-SCs), whose in vivo growth pattern closely replicates human GBM. EphB2 expression stimulated GBM neurosphere cell migration and invasion, and inhibited neurosphere cell proliferation in vitro. In parallel, EphB2 silencing increased tumor cell proliferation and decreased tumor cell migration. EphB2 was found to increase tumor cell invasion in vivo using an internally controlled dual-fluorescent xenograft model. Xenografts derived from EphB2 overexpressing GBM neurospheres also showed decreased cellular proliferation. The non-receptor tyrosine kinase focal adhesion kinase (FAK) was found to be co-associated with and highly activated by EphB2 expression and FAK activation facilitated focal adhesion formation, cytoskeleton structure change and cell migration in EphB2-expression GBM neurosphere cells. Taken together, our findings indicate that EphB2 has pro-invasive and anti-proliferative actions in GBM stem-like neurospheres mediated, in part, by interactions between EphB2 receptors and FAK. These novel findings suggest that tumor cell invasion can be therapeutically targeted by inhibiting EphB2 signaling and that optimal anti-tumor responses to EphB2 targeting may require the concurrent use of anti-proliferative agents.

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 4311. doi:1538-7445.AM2012-4311
Abstract 4312: E3 ligase activity of XIAP RING domain is required for XIAP-mediated cancer cell migration but not for its RhoGDI binding activity
Authors: Yu Yonghui , Liu Jinyi , Zhang Dongyun , Luo Wenjing , Yu Jianxiu , Li Jingxia , Zhang Xinhai , Chen Jingyuan , Huang Chuanshu
Published: August 2012

Although an increased expression level of XIAP is associated with cancer cell metastasis in individuals with various types of cancer, the molecular mechanism linking XIAP to cancer metastasis remains unexplored. Here we show that in XIAP depletion HCT116 cells (XIAP−/−), cell migration, invasion and actin polymerization are decreased, which could be rescued either by the introduction of XIAP RING domain or knockdown of RhoGDI. Subsequent studies demonstrate that this function of the XIAP RING domain depends on its inhibition of RhoGDI SUMOylation at K138. Furthermore, SUMO1-RhoGDI, but not un-sumoylated RhoGDI preferentially binds to Rho GTPase and downregulates the activities of GTPases, including RhoA, Cdc42 and Rac1, by which RhoGDI inhibits cancer cellular actin polymerization and motility. Taken together, our study reveals a novel post-translational modification (SUMOylation) of RhoGDI, and its physiological regulation by the RING domain of XIAP, which may account for XIAP modulation of cancer cell motility.

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 4312. doi:1538-7445.AM2012-4312
Abstract 4313: A novel endoplasmic reticulum protein promotes cancer invasion/metastasis
Authors: Evensen Nikki A. , Kuscu Cem , Pulkoski-Gross Ashleigh , Nguyen Hoang-Lan , Zucker Stanley , Cao Jian
Published: August 2012

Although considerable progress has been made in our understanding of cancer cell invasion, much of this complex cellular process remains a mystery, ultimately hindering advancements in treatment strategies targeting metastasis. Here we report the vital role of a novel endoplasmic reticulum (ER) resident protein identified by a PCR-subtraction hybridization technique, designated Cancer ER Invasion Gene (CERIG), in cancer cell migration and invasion. Clinical relevance of CERIG is highlighted by upregulation of CERIG in human invasive breast cancer specimens examined by immunohistochemistry and real-time RT-PCR, as well as increased expression in various forms of human cancer as determined by data mining. This up-regulation of CERIG correlates with poor prognosis of patients with breast cancer assessed by a DNA microarray data-mining approach from three publicly available cohorts containing a total of 696 breast cancer patients. Mechanistically, increased CERIG in solid tumors is linked to hypoxia-induced activation of CERIG promoter via the hypoxia-inducible factor-2α. Silencing of CERIG in an aggressive breast cancer cell line disrupted mesenchymal morphogenesis in vitro, resulting in a mesenchymal-to-epithelial transition, and interfered with cancer metastasis in vivo. Employing both gain- and loss-of-function approaches, CERIG was found to induce cancer cell migration and invasion. Enhanced cell migration required CERIG retention within the ER, where this 160 kDa protein forms a complex with an ER chaperone protein, GRP78/BiP. The minimal protein domain required for ER retention was identified using a mutagenesis approach. Furthermore, fusion of the ER-retention domain to a soluble matrix metalloproteinase (MMP) prevents the secretion of the MMP and retained it in the ER. Overexpression of CERIG in cells results in diminished ER and increased cytoplasmic calcium levels, suggesting a role for CERIG in ER calcium leakage. Furthermore, chelating intracellular calcium abrogates CERIG induced cell migration. The induction of cell migration via CERIG was found to involve a CERIG-BiP-ER calcium leakage-PKC-MAPK pathway. Our data indicate that CERIG, as a novel ER resident protein, plays an important role in cancer progression, serving as a novel cell migration-promoting 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 4313. doi:1538-7445.AM2012-4313