bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A82: The role of PI3-kinase signaling pathway in invadopodia formation
Authors: Yamaguchi Hideki , Yoshida Nachi , Sakai Ryuichi
Published: August 2014

Degradation of extracellular matrix that is present in the basement membrane and tumor stroma is essential for local invasion and formation of metastatic sites by malignant cancer cells. Invadopodia are extracellular matrix-degrading protrusions formed by invasive cancer cells that have been shown to function in cancer invasion and metastasis. Although many invadopodia components have been identified, signaling pathways that link extracellular stimuli to invadopodia formation remain poorly understood. The phosphoinositide 3-kinases (PI3Ks) are a family of lipid kinases that phosphorylate phosphoinositides at the D-3 position of the inositol headgroup. PI3Ks mediate the signal transduction of extracellular stimuli and regulate diverse cellular events. Uncontrolled activation of the PI3K signaling pathway leads to tumorigenesis and tumor malignancy. In this study, we investigated the role of PI3K signaling during invadopodia formation. We found that in human breast cancer cells both invadopodia formation and degradation of a gelatin matrix were blocked by treatment with PI3K inhibitors or sequestration of D-3 phosphoinositides. Functional analyses revealed that among the PI3K family proteins the class I PI3K catalytic subunit p110α, a frequently mutated gene product in human cancers, was selectively involved in invadopodia formation. The expression of p110α with cancerous mutations promoted invadopodia-mediated invasive activity. Furthermore, knockdown or inhibition of PDK1 and Akt suppressed invadopodia formation induced by p110α mutants. These data suggest that PI3K signaling via p110α regulates invadopodia-mediated invasion of breast cancer cells.

Citation Format: Hideki Yamaguchi, Nachi Yoshida, Ryuichi Sakai. The role of PI3-kinase signaling pathway in invadopodia formation. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr A82.
Abstract A89: Sulfated polysaccharides from marine brown alga alleviate pancreatic cancer metastasis
Authors: Delma Caroline R. , Thirugnanasambandan Somasundaram S. , Srinivasan Guruprasad , Aravindan Sheeja , Natarajan Mohan , Herman Terence S. , Aravindan Natarajan
Published: August 2014

Pancreatic cancer is one of the most deadly cancers with a five year survival rate of less than six percent. The poor prognosis can be attributed to the fact that more than three fourth of the patients have metastasis at the time of diagnosis. In view of the increasing evidence that sulfated polysaccharides attenuate tumor invasion, we attempted to evaluate the anti-metastatic potential of sulfated polysaccharide fractions from a marine brown alga, Turbinaria conoides in pancreatic cancer. Exposure of human pancreatic adenocarcinoma cells (MiaPaCa-2, Panc-1, BxPC-3 and Panc-3.27) to partially purified polysaccharide fractions showed a negative regulation of both the transcriptional activation (QPCR) and cellular expression (immunoblotting) of adhesion molecules, Mucin-16, E-Selectin and metastasis efficiency modifying SPA 1 and Dnmt3b. All encompassed, transcriptional profiling pertaining to tumor invasion and metastasis (QPCR profiling) revealed cell-type unique, yet comprehensive inhibition, including 62, 65, 64 and 51 of 93 transcripts in Mia PaCa-2, Panc-1, BxPC3 and Panc-3.27 cells, respectively. Extracellular matrix metalloproteinases MMP-2 and MMP-9, which play a significant and definite role in the invasion and metastasis of pancreatic cancer were completely muted as evidenced by reduced activity (by gelatin zymography) and secretion (by immunoblotting) in cells exposed to all fractions. Relatively, fraction V showed robust inhibitory potential in this setting. Together, these data suggest that fractions of sulfated polysaccharides, specifically fraction V, may serve as a potential drug deliverable to alleviate pancreatic cancer metastasis. This study prompts us to investigate further the active constituents in the sulfated polysaccharide fraction and their target binding affinity, (here in this case, to MUC16 and/or MMPs) and their mode of signal transduction. These in vitro studies and studies testing its efficacy in an in vivo setting are currently in process in our laboratory.

Citation Format: Caroline R. Delma, Somasundaram S. Thirugnanasambandan, Guruprasad Srinivasan, Sheeja Aravindan, Mohan Natarajan, Terence S. Herman, Natarajan Aravindan. Sulfated polysaccharides from marine brown alga alleviate pancreatic cancer metastasis. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr A89.
Abstract B100: Genomic copy number alterations associated with the early brain metastasis of non-small cell lung cancer
Authors: Lee Hye Won , Lee Se Jeong , Song Mi Young , Joo Kyeung Min , Nam Do-Hyun
Published: August 2014

Frequent early development of systemic metastasis leads unfavourable clinical prognosis of the non-small cell lung cancer (NSCLC). Although the brain metastasis (BM) contributes significantly to the morbidity and mortality of NSCLC, relevant driver mechanisms are largely unknown. To elucidate genetic alterations and prognostic markers associated with early BM of NSCLC, we retrospectively collected 18 NSCLC patients with BM (12 adenocarcinomas (ADC) and 6 squamous cell carcinomas (SQCC)) whose surgical tissues of primary and/or metastatic tumors were preserved as formaldehyde fixed and paraffin embedded (FFPE) pathologic samples. When chromosomal copy number alterations (CNAs) of those FFPE samples were analysed by the Molecular Inversion Probe (MIP) technology, the most frequent CNAs detected in primary ADCs were gains of 3q, 5p, 5q, 6p, 8q, 9p, 11p, 15q, 17q and losses of 10q and 22q whereas primary SQCCs revealed gains in 4q and 12q and loss in 9q. Moreover, comparative MIP analysis on 11 matched cases demonstrated the fact that the BM carried the majority of genetic alterations present in the corresponding primary tumor but with a slightly higher frequency including gain of 9p11 and loss of 2p11 in ADCs. Especially, when primary 12 ADCs were analyzed depending on the pattern of BM to uncover predetermining signatures that can predict the risk of BM, selectively amplified regions of primary lung ADCs (5q35, 10q23 and 17q23-24) were identified as significantly associated with the development of early BM within 3 months after first diagnosis of primary tumor. Small interfering RNA silencing of ACTA2, which is one of several candidate genes revealed in this study, reduced the in vitro migratory and invasive potential of human ADC cell line PC14PE6-GFP tagged cells without affecting on proliferation. Although more validation is needed, the genetic signatures elucidated in this study shed light on the molecular mechanisms involved in BM and help to identify prognostic markers stratifying the subgroup at high risk of developing recurrence or distant metastasis within heterogeneous NSCLC patients.

Citation Format: Hye Won Lee, Se Jeong Lee, Mi Young Song, Kyeung Min Joo, Do-Hyun Nam. Genomic copy number alterations associated with the early brain metastasis of non-small cell lung cancer. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr B100.
Abstract B18: MiR-205 puts the brakes on the malignant interplay between prostate cancer cells and associated fibroblasts
Authors: Gandellini Paolo , Giannoni Elisa , Casamichele Anna , Taddei Maria Letizia , Callari Maurizio , Valdagni Riccardo , Zaffaroni Nadia , Chiarugi Paola
Published: August 2014

Tumor microenvironment is a strong determinant for the acquisition of metastatic potential of cancer cells. We have recently demonstrated that cancer associated fibroblasts (CAFs) elicit an epithelial-mesenchymal transition (EMT) in prostate cancer (PCa) cells, leading to enhanced tumor cell aggressiveness. Here, we investigated the involvement of microRNAs (miRNA) in such malignant tumor-stroma interplay, to identify possible tools to prevent metastasis dissemination. We found that miR-205 is the most down-modulated miRNA in PCa cells upon CAF stimulation and acknowledged HIF-1 to be a direct repressor of miRNA transcription. Rescue experiments demonstrated that ectopic miR-205 over-expression in PCa cells counteracts CAF-induced EMT, thus impairing enhancement of cell invasion, acquisition of stem cell traits, tumorigenicity and metastatic dissemination. In addition, miR-205 can block tumor-driven activation of surrounding fibroblasts, by reducing pro-inflammatory cytokine secretion. Overall, these findings suggest a key role of miR-205 in the bidirectional interplay between PCa cells and fibroblasts. In addition, the evidence that miR-205 replacement in PCa cells is able not only to prevent but also to revert EMT induced by CAFs sets up the rationale for developing miRNA-based approaches for the prevention and treatment of aggressive tumors.

Citation Format: Paolo Gandellini, Elisa Giannoni, Anna Casamichele, Maria Letizia Taddei, Maurizio Callari, Riccardo Valdagni, Nadia Zaffaroni, Paola Chiarugi. MiR-205 puts the brakes on the malignant interplay between prostate cancer cells and associated fibroblasts. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr B18.
Abstract B31: An interspecies comparison between the structure and products of the parathyroid hormone-related peptide gene
Authors: Freeman Adam , Martin T. J.
Published: August 2014

The Parathyroid Hormone-related Peptide (PTHrP) is widely expressed across many species. It acts as a key regulator of cellular metabolic control, including calcium metabolism, and plays a significant role in the development and maintenance of many normal tissues. It also plays an intriguing role in neoplasia of multiple organs, and is thought integral to Breast Cancer in particular. PTHrP has been characterised in many animals in addition to humans. A review of the contemporaneous literature was performed to make this comparison. Although its complexity and composition differ, the PTHrP gene has been shown to have several well-conserved regions across different species; gene products have demonstrated physiological inter-species activity. Three main functional domains have been identified in humans, with similarities in other species. Examination of these areas has yielded insight into the physiology and function of the gene. In humans, potential splicing of PTHrP pre-messenger RNA yields three potential isotypes of 139, 141, and 173 amino acids. Whereas rats and mice produce 141 and 139; chickens several 139 amino acid peptides; Xenopus a 144 and 131; sea bream125 and 126 ; and the elephant shark a single 156 amino acid product. These genes are represented graphically and a review of functional domains is performed.

Citation Format: Adam Freeman, T. J. Martin. An interspecies comparison between the structure and products of the parathyroid hormone-related peptide gene. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr B31.
Abstract B42: Dichotomus role of profilin in early vs. late steps of breast cancer metastasis
Authors: Roy Partha
Published: August 2014

Profilin1 (Pfn1), an essential control element for actin polymerization, plays indispensable role in migration and proliferation of normal cells. Seemingly contrary to these essential cellular functions of Pfn1, its expression is downregulated in breast cancer, the significance of which is unclear. In this study, expression profiling of Pfn1 in human breast cancer specimens of various histopathological stages correlate lower Pfn1 expression levels with propensity to metastasize. Xenograft studies uncover a unique dichotomous role of Pfn1 in early vs late steps of breast cancer metastasis. Specifically, loss of Pfn1 expression promotes dissemination of breast cancer cells from the primary mammary tumor but metastatic colonization of breast cancer cells is critically dependent on Pfn1's function. In the context of dissemination, breast cancer cells exhibit increased sustenance of PI3K signaling and acquire a hyper-invasive phenotype (marked by MMP9 upregulation, faster invasion through collagen matrix) involving a PI3K-PI(3,4)P2 signaling axis when Pfn1 expression is suppressed. In addition, Pfn1-deficient breast cancer cells display increased proficiency to cross through an endothelial cell barrier (an obligatory step for vascular dissemination) in a VEGF-dependent manner, respectively. Gene expression profiling combined with biochemical analyses of secreted proteins show that loss of Pfn1 impacts expression of several other pro-invasive and pro-metastatic genes. Finally, correlated with hyper-invasive phenotype of breast cancer cells caused by Pfn1 depletion, we found that mammary-specific deletion of Pfn1 gene expedites ductal outgrowth. In summary, contrasting the well-established pro-migratory role of Pfn1 in the physiological contexts, our findings set the first in vivo example of a context-specific effect of loss of Pfn1 in cell motility-dependent processes such as mammary gland morphogenesis and metastatic dissemination.

Citation Format: Partha Roy. Dichotomus role of profilin in early vs. late steps of breast cancer metastasis. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr B42.
Abstract B47: New role for α-catenin family member α-catulin in squamous cell carcinoma invasion and metastasis.
Authors: Cao Christine , Chen Yibu , Masood Rizwan , Sinha Uttam , Kobielak Agnieszka
Published: August 2014

The capacity of tumor cells to produce metastases is the main features of malignant tumors and the main causes of death for cancer. Squamous cell cancers comprise the most common types of human epithelial cancers. One subtype, head and neck squamous cell carcinoma (HNSCC), is a particularly aggressive cancer with poor prognosis due to late diagnosis and metastasis. Here we find that in vivo, the α-catenin homologue — α-catulin, is highly expressed at the tumor invasion front and in the metastatic streams of cells in both malignant human HNSCCs and a mouse model of oral SCC. Knockdown of α-catulin in hHNSCC cell lines dramatically decrease the migratory and invasive potential of those cells in vitro and metastatic potential in xenotransplants in vivo. Analysis of tumors deficient in α-catulin showed that the tumor cells are unable to invade the surrounding stroma. Accordingly, transcriptional profiling of those tumors revealed that α-catulin ablation is accompanied by changes in genes involved in cell migration and invasion. In vitro an upregulation of α-catulin expression correlates with the transition of tumor cells from an epithelial to a mesenchymal morphology, as well as an upregulation of EMT markers vimentin and snail. Overall, these results strongly indicate that α-catulin contributes to the invasive behavior of metastatic cells, and may be used as a prognostic marker and future therapeutic target for cancer patients.

Citation Format: Christine Cao, Yibu Chen, Rizwan Masood, Uttam Sinha, Agnieszka Kobielak. New role for α-catenin family member α-catulin in squamous cell carcinoma invasion and metastasis.. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr B47.
Abstract B56: A lineage-selective transcriptional pathway linking lung differentiation and cancer metastasis
Authors: Cheung William K.C. , Zhao Minghui , Liu Zongzhi , Cao Paul D. , Stevens Laura E. , Westbrook Thomas F. , Nguyen Don X.
Published: August 2014

Lung cancer is the leading cause of cancer-related deaths worldwide. This poor prognosis is due to the rapid metastatic progression of this disease, yet the mechanisms that govern lung cancer dissemination and colonization are unclear. Through an integrated approach, we identified an alveolar cell-selective gene signature that stratifies lung adenocarcinoma (ADC) into molecular subtypes of distinct prognosis and differentiation states. This transcriptional program is regulated in part by the cell fate transcription factors, GATA6 and HOPX, which are normally required for proper alveolar differentiation. In an experimental model, suppression of GATA6 and HOPX cooperatively enhances metastatic competence of lung ADC cells. Whole genome RNA sequencing reveals that this transcriptional network can modulate specific target genes and pathways involved in airway epithelial differentiation and invasion. Our findings identify a novel cell lineage molecular program whose perturbation enhances lung cancer metastasis.

Citation Format: William K.C. Cheung, Minghui Zhao, Zongzhi Liu, Paul D. Cao, Laura E. Stevens, Thomas F. Westbrook, Don X. Nguyen. A lineage-selective transcriptional pathway linking lung differentiation and cancer metastasis. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr B56.
Abstract B60: Analysis of the endocytic receptor MRC2 as a target for mesenchymal pancreatic cancer cells
Authors: Sinha Arkadeep , Watanabe Aprill , Winter Jordan , Allen Peter , Hostetter Galen , Haab Brian B.
Published: August 2014

The poor outcome of pancreatic cancer is hypothesized to be due to a subset of cancer cells that have elevated propensity to metastasize and are resistant to current chemotherapeutics. In vitro, the process of epithelial to mesenchymal transition (EMT) has been shown to grant cells with the aforementioned properties. Hence, it has been hypothesized that the process of EMT might have answers to controlling the metastatic cascade. Using gene expression microarrays, MRC2 expression was found to be upregulated when cells undergo EMT. MRC2 is a transmembrane protein known for its role in collagen degradation. Its role in the progression of metastatic pancreatic cancer and in vivo expression was assayed for validation as a drug target. MRC2 upregulation by TGF-β1 did not promote increased transition to a mesenchymal phenotype or migratory ability in the absence of a chemotactic gradient. However, using boyden chamber and matrigel invasion assays, it was observed that MRC2 affects chemotactic and invasive ability. Immunohistochemical analysis of over 250 pancreatic tumors revealed that MRC2 is upregulated in the cancer samples especially in the stromal compartment. MRC2 staining patterns were consistent with involvement in invasion, including elevation in individual, invading cancer cells and stromal elevations in peri-tumoral and poorly differentiated regions. Blinded immunohistochemical studies disclosed a correlation between elevated stromal MRC2 levels and poor prognosis. Flow cytometry is being used on primary tumors to confirm the dual stain results hinting towards the elevation of MRC2 on a subset of pancreatic cancer cells in vivo. Dual stains on tissue microarrays are also being used to identify the stromal cell population showing MRC2 elevation. Based on the role of MRC2 in chemotactic invasion and extracellular matrix remodeling, loss of cells expressing MRC2 might be a deterrent for metastasis. Since MRC2 is part of an endocytic pathway,upon confirmation of MRC2 as a marker of the mesenchymal cancer cells, it has the potential for use as an adjuvant targeted therapy for the treatment of pancreatic cancer.

Citation Format: Arkadeep Sinha, Aprill Watanabe, Jordan Winter, Peter Allen, Galen Hostetter, Brian B. Haab. Analysis of the endocytic receptor MRC2 as a target for mesenchymal pancreatic cancer cells. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr B60.
Abstract B67: Metadherin mediates osteosarcoma invasion and metastasis
Authors: Zhu Limin , Buford Adrianna S. , Yang Yanwen , Zhang Pingyu , Wang Wei-Lien , Hughes Dennis P.
Published: August 2014

Osteosarcoma is the most common type of bone malignancy in children. It is a highly invasive mesenchymal tumor in which metastasis accounts for the vast majority of mortality and morbidity in patients. Understanding the mechanisms controlling metastasis in osteosarcoma and developing novel therapeutic options targeting metastasis are essential for improving patient survival in this disease. Recent studies have shown that Metadherin (MTDH) plays a key role in mediating metastasis in a variety of human cancers. This study examined the role of MTDH in osteosarcoma metastasis and elucidated the mechanisms underlying its oncogenic activity.

We used western blot, qPCR, and flow cytometry to measure the expression of MTDH in a panel of osteosarcoma cell lines. Patient-derived osteosarcoma samples were also examined for MTDH expression using immunohistochemistry. In parallel experiments we used MTDH-specific shRNA to down-regulate endogenous MTDH expression, and blocked cell surface MTDH by anti-MTDH antibodies. The impact of MTDH inhibition was assessed in vitro using migration assays and matrigel invasion assays. We also developed an osteosarcoma orthotopic xenograft model of NOD/SCID/IL2Rγ-deficient mice through intratibial injection of osteosarcoma cells with or without MTDH knockdown to study the relationship between MTDH expression and pulmonary metastatic potential of osteosarcoma cells.

Compared to normal human osteoblasts, all osteosarcoma cell lines tested displayed elevated MTDH expression as shown by western blot, qPCR and flow cytometry analyses. MTDH knockdown reduced migration and decreased invasion in matrigel. Inhibition of cell surface MTDH with an anti-MTDH antibody targeting the extracellular domain of MTDH also profoundly impeded osteosarcoma cell motility and invasiveness in vitro. In an orthotopic xenograft mouse model using CCHD cells, inhibition of MTDH delayed primary tumor growth and prohibited pulmonary metastasis. All mice in the control group developed lung metastases while fewer than 20% of the mice in the MTDH-knockdown group showed sign of metastasis at six weeks after inoculation. MTDH knockdown also reduced mean lung weight and mean number of pulmonary metastasis. Immunohistochemical analysis of tumor samples showed that lung metastases had elevated MTDH expression level compared to primary tumors.

Altogether these studies suggested that MTDH plays a critical role in promoting pulmonary metastasis of osteosarcoma and may serve as an attractive target for therapeutic intervention.

Citation Format: Limin Zhu, Adrianna S. Buford, Yanwen Yang, Pingyu Zhang, Wei-Lien Wang, Dennis P. Hughes. Metadherin mediates osteosarcoma invasion and metastasis. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr B67.
Abstract B80: Deletion of Smad4 results in enhancement of lymphangiogenesis and node metastasis in head and neck squamous cell carcinoma
Authors: Oka Masako , Chen Xi , Wang Xiao-Jing , Lu Shi-Long
Published: August 2014

Lymph node metastasis is the single most important clinical prognostic factor in human head and neck squamous cell carcinoma (HNSCC). The 5-year overall survival is reduced by approximately 50% in HNSCC patients with node metastasis. Understanding the molecular mechanisms of lymph node metastasis in HNSCC is thus of pivotal importance for improving patient's survival. It has been shown that increased lymphatic vessel density in HNSCC tumors correlates with high metastasis rate to lymph nodes, suggesting a connection of enhancement of lymphangiogenesis and node metastasis in HNSCC. We have recently shown that deletion of Smad4, a tumor suppressor commonly inactivated in human HNSCC patients, in a genetically engineer mouse model developed head and neck squamous cell carcinomas with metastasis to cervical lymph nodes. Moreover, examining Smad4 expression and lymphangiogenesis marker podoplanin by immunohistochemistry in human HNSCC patients with node metastasis revealed a negative correlation between Smad4 and podoplanin, validating our initial findings from the Smad4 knockout mouse model. To further investigate the functional role of Smad4 in lymphangiogenesis and node metastasis, we restored Smad4 expression in a Smad4-deficient HNSCC cell line, Cal27. We then orthotopically injected both cell lines on the floor of mouth of nude mice, and observed tumor formation and cervical lymph node metastasis around 7 weeks. Analysis of tumor tissues showed that Smad4 restoration reduced lymphangiogenesis, as revealed by LYVE1, a lymphangiogenesis marker immunostaining. Furthermore, the rate of cervical lymph node metastasis is decreased upon the Smad4 restoration. The potential molecular mechanism of Smad4 in regulating lymphangiogenesis is currently undergoing. In conclusion, our studies have shown the deletion of Smad4 increases lymphangiogenesis and node metastasis from both HNSCC mouse models and human patient samples. Further investigation of the underneath molecular mechanism will be ultimately translated into novel therapeutical approaches for controlling lymph node metastasis and improving survival for human HNSCC patients.

Citation Format: Masako Oka, Xi Chen, Xiao-Jing Wang, Shi-Long Lu. Deletion of Smad4 results in enhancement of lymphangiogenesis and node metastasis in head and neck squamous cell carcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr B80.
Abstract B88: Deficiency for endoglin in tumor vasculature weakens the endothelial barrier to metastatic dissemination
Authors: Cunha Sara I.
Published: August 2014

Therapy-induced resistance remains a significant hurdle to achieve long-lasting responses and cures in cancer patients. Here, we investigated the long-term consequences of genetically impaired angiogenesis by engineering multiple tumor models deprived of endoglin, a co-receptor for TGF-beta in endothelial cells actively engaged in angiogenesis. Tumors from endoglin-deficient mice adapted to the weakened angiogenic response and refractoriness to diminished endoglin signaling was accompanied by increased metastatic capability. Mechanistic studies in multiple mouse models of cancer revealed that deficiency for endoglin resulted in a tumor vasculature that displayed hallmarks of endothelial-to-mesenchymal transition; a process of previously unknown significance in cancer biology, but here shown to be associated with a reduced capacity of the vasculature to avert tumor cell intra- and extravasation. Nevertheless, tumors deprived of endoglin exhibited a delayed onset of resistance to anti-VEGF agents, illustrating the therapeutic utility of combinatorial targeting of multiple angiogenic pathways for the treatment of cancer.

Citation Format: Sara I. Cunha. Deficiency for endoglin in tumor vasculature weakens the endothelial barrier to metastatic dissemination. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr B88.
Abstract B94: Gene expression profiling during EMT and MET identifies multiple transcription factors involved in the EMT transcriptional reprogramming
Authors: Voronkova Maria , Addison Joseph , Galeeva Renata , Denvir James , Chen Dongquan , Ivanov Alexey
Published: August 2014

Background and Objective: The Epithelial-to-Mesenchymal Transition (EMT) is a developmental program which is often reactivated in aggressive metastatic breast cancer. Several transcription factors (TFs), such as Snail and ZEB can act as master regulators of EMT, directly repressing the gene for E-cadherin. We sought to identify common gene expression signatures characteristic to both EMT and a reverse process, Mesenchymal-to-Epithelial Transition (MET).

Methods: Using Affymetrix Exon microarrays we characterized global gene expression changes in two cellular models: normal mammary epithelial HMLE cells induced to undergo EMT by expression of Snail1, Snail2 or ZEB1; and MDA-MB-231LN breast cancer cells induced to undergo MET by depletion of ZEB1 and ZEB2.

Results: We identified two large gene sets: 1) 1017 genes down-regulated during EMT and up-regulated during MET, which we designated as MET-specific; and 2) 438 genes up-regulated during EMT and down-regulated during MET, which we designated as EMT-specific. 14 TFs were found in the EMT category. Their functional validation showed that individual overexpression of several of these TFs in HMLE cells was sufficient to elicit partial EMT.

Discussion and Conclusions: Our comprehensive analysis of gene expression signatures common to EMT and MET identifies the EMT transcriptional program characteristic to invasive metastatic breast cancer.

Grant support: NIH NCRR grant P20 RR16440 and Susan G. Komen for the Cure grant KG110350.

Citation Format: Maria Voronkova, Joseph Addison, Renata Galeeva, James Denvir, Dongquan Chen, Alexey Ivanov. Gene expression profiling during EMT and MET identifies multiple transcription factors involved in the EMT transcriptional reprogramming. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr B94.
Abstract C27: Potential contributions of genome-stabilizing activity of NM23 to its metastasis suppressor function in melanoma
Authors: Jarrett Stuart G. , Novak Marian , Cook Gemma S. , Kaetzel David M.
Published: August 2014

Metastasis suppressor activity of NM23-M1 (NM23-H1 in human) in melanoma has been established using melanoma cell lines in culture and, more recently, in a model of UV-induced melanoma using NM23 knockout mice. While NM23-M1/H1 is clearly a suppressor of melanoma cell motility, we have recently shown it also exhibits genome-stabilizing activity, promoting repair of both spontaneous and UV-induced DNA damage via the nucleotide excision repair pathway. These findings suggest NM23 proteins may also inhibit metastasis by suppressing acquisition of metastasis-driving mutations and other genomic aberrations. To dissect the molecular mechanisms through which NM23 contributes to genomic stability, this study focused on the double-strand break repair (DSBR) pathway. All members of the NM23 family of proteins possess nucleoside diphosphate kinase (NDPK) activity, which could enhance nucleotide availability during polymerase-mediated repair, and 3'5' exonuclease activity which has been suggested to be critical in the non-homologous end-joining (NHEJ) pathway of DSBR. To first determine whether NM23 is indeed recruited to DSBs, these lesions were produced in the human melanoma cell line WM793 using a tamoxifen-inducible form of the restriction endonuclease I-PpoI via a retroviral vector. Induction of I-PpoI-catalyzed DSBs resulted in recruitment of both endogenous NM23 and recombinant Flag-tagged H1 (Flag-H1) to a known I-PpoI cleavage site within 30 min, as demonstrated by chromatin immunoprecipitation. The rapid appearance of NM23-H1 at the DSB coincided with that of the damage sensor ATM, and disappearance of histone 2B. Forced expression of NM23-H1 resulted in significantly enhanced repair of the known I-PpoI-induced DSB site, shown using a quantitative PCR across the lesion, indicating a functional contribution of the protein to DSBR. Induction of DSBs resulted in colocalization of Flag-H1 with γ-histone 2AX within small intranuclear foci, also consistent with recruitment of NM23-H1 directly to DSB lesions. Induction of DSBs using the DNA topoisomerase II inhibitor etoposide resulted in rapid nuclear colocalization within 5 minutes of Flag-H1 and ribonucleotide reductase, suggesting cooperative actions of these two enzymatic activities during DSBR. These studies are the first to demonstrate recruitment of NM23-H1 directly to sites of DNA damage, and suggest the possibility that NM23 deficiency in melanoma and other human cancers accelerates the acquisition of metastasis-driving mutations during cancer progression.

Citation Format: Stuart G. Jarrett, Marian Novak, Gemma S. Cook, David M. Kaetzel. Potential contributions of genome-stabilizing activity of NM23 to its metastasis suppressor function in melanoma. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr C27.
Abstract C33: Akt-EphA2 signaling axis promotes diffuse infiltrative invasion of glioma in vivo and regulates glioma stem cell properties
Authors: Miao Hui , Gale Nickolas W. , Wang Bingcheng
Published: August 2014

Glioblastoma multiforme (GBM) is among the most lethal types of human cancer. Diffuse infiltrative invasion is a major cause for the poor prognosis; however the underlying mechanisms remain to be fully elucidated. Using human glioblastoma stem-like cells (GSCs) that recapitulate the highly invasive propensity of primary glioblastomas, we find that ephrin receptor A2 (EphA2) critically regulates glioma invasion in vivo. ShRNA knockdown of EphA2 markedly diminished intracranial invasion. Conversely overexpression of EphA2 enhanced the invasion. The effects required Akt-mediated phosphorylation of EphA2 on serine 897. In vitro, the Akt-EphA2 signaling axis in GSCs was maintained in the absence of ephrin-A ligands and disrupted upon ligand stimulation. In accordance, GSCs invasion was significantly increased in brain slices from the Efna1;Efna3;Efna4 triple knockout mice compared with those from the wild type littermates. Mechanistically overexpression of wild type but not S897A mutant EphA2 promoted GSC self-renewal, which was correlated with the increased expression of stem cell markers. Taken together, the results show that EphA2 stimulates glioma invasiveness in vivo in cooperation with Akt, which is negatively regulated by ephrin-As in tumor microenvironment.

Citation Format: Hui Miao, Nickolas W. Gale, Bingcheng Wang. Akt-EphA2 signaling axis promotes diffuse infiltrative invasion of glioma in vivo and regulates glioma stem cell properties. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr C33.
Abstract C41: MenaINV dysregulation of receptor tyrosine kinase signaling
Authors: Oudin Madeleine J. , Hughes-Alford Shannon K. , Miller Miles , Asokan Sreeja B. , Bear James E. , Lauffenburger Doug A. , Gertler Frank B.
Published: August 2014

Mena, an actin regulatory protein, is upregulated in human breast cancer and its expression is associated with increased metastatic progression. An invasion-specific isoform, MenaINV, is upregulated selectively in invasive tumor cells and increases invasion and metastasis by potentiating tumor cell responses to EGF. MenaINV causes dysregulation of the tyrosine phosphatase PTP1B, leading to increased phosphorylation of EGFR and other downstream targets. We investigated whether MenaINV could similarly promote invasion through dysregulation of signaling downstream of other receptor tyrosine kinases (RTKs). The behavior of MDA-MB-231 triple negative breast cancer cells stably expressing MenaINV or the other cannonical, broadly expressed Mena lacking the “INV” exon was measured after growth factor treatment in two migration assays: a 2D protrusion assay on matrigel and collagen coated coverslips and a 3D invasion assay into collagen gels. We found that expression of MenaINV sensitized responses to other EGFR ligands including HB-EGF and amphiregulin. In addition, MenaINV expression enhanced responses mediated by two other RTKs associated with tumor progression, Met and IGFR, both known PTP1B substrates. Cells expressing MenaINV respond to 20-fold lower concentrations HGF and IGF than control cells. However, there was no effect of MenaINV on responses to the ERBB3 ligand neuregulin and the chemokine SDF-1.

Recently we reported that Mena can regulate cell motility in fibroblasts via its interaction with α5β1 integrin, which is known to co-traffic with EGFR and other RTKs to regulate invasion in tumor cells expressing mutant p53 or upon inhibition of αvβ3. We asked whether the direct interaction of Mena with α5β1 also contributes to invasion. Disrupting the interaction between the Mena isoforms and α5β1 in MDA-MB-231 cells affected how cells responded to EGF in a 3D collagen gel. In addition, fibroblasts that were null for Mena were unable to respond to a fibronectin gradient in a haptotaxis assay.

Overall, these results suggest that the effects of MenaINV on invasion and metastasis could be mediated via different RTKs, as well as through direct interaction with integrins and the extracellular matrix. Experiments are currently underway to investigate how MenaINV regulates signalling downstream of these RTKs and integrins, to understand the molecular mechanism underlying the pro-metastatic effect of MenaINV.

Citation Format: Madeleine J. Oudin, Shannon K. Hughes-Alford, Miles Miller, Sreeja B. Asokan, James E. Bear, Doug A. Lauffenburger, Frank B. Gertler. MenaINV dysregulation of receptor tyrosine kinase signaling. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr C41.
Abstract C71: DEAR1 orchestrates selective control over the epithelial-mesenchymal transition axis of TGFβ's function
Authors: Chen Nanyue , Balasenthil Seetharaman , Cao Yu , Killary Ann M.
Published: August 2014

Little is known about the cellular mechanisms that govern the context dependent roles of the critical cytokine TGFβ, which functions in breast cancer as either a tumor suppressor to restrict proliferation in early stage disease or a master driver of epithelial-mesenchymal transition during invasion and metastasis. We previously reported the discovery of the TRIM protein DEAR1(annotated as TRIM62) as a gene that is mutated and homozygously deleted in early onset breast cancers and functions as a dominant regulator of acinar morphogenesis in three dimensional (3D) culture, suggesting that DEAR1 is a novel tumor suppressor that regulates both polarity and tissue architecture. Herein we demonstrate that loss of function of DEAR1 in immortal mammary epithelial cells (HMECs) resulted in a failure of acinar morphogenesis in the presence of TGFβ and was required for TGFβ-induced cell migration, invasion and anoikis resistance, all of which key indicators of TGFB-driven EMT. However, DEAR1 loss did not affect TGFβ-induced proliferation suppression, indicative that DEAR1 exerts a selective negative control over TGFβ-mediated EMT oncogenic functions while preserving TGFβ's growth suppressive functions. These results indicate that the mechanisms governing the dual functions of TGFβ are separable and that it is possible to selectively block the deleterious arm of TGFβ's function. In addition, DEAR1 suppressed TGFβ-SMAD3 signaling by binding to and ubiquitinating SMAD3, the major effector of TGFβ-meditated EMT. Furthermore, treatment of DEAR1 knockdown HMECs with a SMAD3 inhibitor or SMAD3 shRNA rescued the DEAR1 loss of function phenotype as evidence by the downregulation of expression of EMT markers and inhibition of migration induced by TGFβ in strong support that DEAR1 specifically blocks TGFβ-induced EMT through the regulation of SMAD3 protein levels and suggestive that results could have clinical significance for stratifying breast cancers for targeted therapies aimed at the oncogenic arm of this pathway. These data demonstrate a significant role for DEAR1 in the control of TGFβ-induced EMT as well as present a novel paradigm for regulation of one of the most important pathways aberrant in human breast cancer.

Citation Format: Nanyue Chen, Ret., Seetharaman Balasenthil, Yu Cao, Ann M. Killary. DEAR1 orchestrates selective control over the epithelial-mesenchymal transition axis of TGFβ's function. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr C71.
Abstract C75: miR-7 suppresses brain metastasis of cancer stem-like cells by modulating Kruppel-like factor 4 in breast cancer
Authors: Xing Fei , Okuda Hiroshi , Kobayashi Aya , Pandey Puspa R. , Pandey Puspa R. , Sharma Sambad , Mo Yin-Yuan , Liu Yin , Wu Kerui , Watabe Kounosuke
Published: August 2014

The majority of cancer death of breast cancer attributed to metastatic disease. Despite this clinical importance, the exact pathological process of tumor metastasis is as yet poorly understood, and deciphering the exact molecular mechanism of this process is of paramount importance in order to identify specific therapeutic targets for this devastating disease. Recent active research in microRNA identified a series of this type of molecules that are involved in tumor progression in various tumors as oncogenes and tumor suppressors. Cancer stem-like cells (CSCs) are considered to play a role in metastatic progression of breast cancer; however, the exact pathological role of CSCs is yet to be elucidated. In this report, we found that CSCs (CD24-/CD44+/ESA+) isolated from metastatic breast cell lines are significantly more metastatic than non-CSC populations in an organ specific manner. The results of our microRNA profile analysis for these cells revealed that CSCs that are highly metastatic to bone and brain expressed significantly lower level of miR-7 and that this microRNA was capable of modulating one of the essential genes for induced pluripotent stem cell, KLF4. Interestingly, high expression of KLF4 was significantly and inversely correlated to brain- but not bone-metastasis free survival of breast cancer patients, and we indeed found that the expression of miR-7 significantly suppressed the ability of CSCs to metastasize to brain but not to bone in our animal model. We also examined the expression of miR-7 and KLF4 in brain-metastatic lesions and found that these genes were significantly down- or up-regulated, respectively, in the tumor cells in brain. Furthermore, the results of our in vitro experiments indicate that miR-7 attenuates the abilities of invasion and self-renewal of CSCs by modulating KLF4 expression. These results suggest that miR-7 and KLF4 may serve as biomarkers or therapeutic targets for brain metastasis of breast cancer.

Citation Format: Fei Xing, Hiroshi Okuda, Aya Kobayashi, Puspa R. Pandey, Puspa R. Pandey, Sambad Sharma, Yin-Yuan Mo, Yin Liu, Kerui Wu, Kounosuke Watabe. miR-7 suppresses brain metastasis of cancer stem-like cells by modulating Kruppel-like factor 4 in breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr C75.
Abstract C78: Integrin αvβ3 drives stemness in the pregnant and neoplastic mammary gland
Authors: Desgrosellier Jay , Lesperance Jacqueline , Seguin Laetitia , Cheresh David
Published: August 2014

Carcinoma cell expression of the integrin αvβ3 is associated with enhanced tumorigenicity and metastasis in a diverse array of human tumors. Here, we reveal αvβ3 expression in a subset of CD44+CD24-/low cancer stem cells in human breast tumor biopsies. In fact, αvβ3 is both necessary and sufficient to account for stem-like properties in breast tumor cells, suggesting that αvβ3 may contribute to mammary stem (MaSC)/progenitor cell behavior. While αvβ3 is a luminal progenitor marker in the virgin murine mammary gland, we noted a dramatic, but transient, increase in αvβ3 levels that defined the mammary stem cell pool at mid-pregnancy. Genetic deletion of β3 surprisingly had no effect on luminal progenitor behavior or ductal morphogenesis. In contrast, β3 was specifically required for MaSC clonogenicity and alveologenesis at mid-pregnancy, yet had no influence on MaSCs in the virgin gland. These findings reveal an unexpected role for αvβ3 in driving mammary stemness during pregnancy that may be related to the stem-like properties, and high metastatic potential associated with αvβ3 expression in human breast cancers.

Citation Format: Jay Desgrosellier, Jacqueline Lesperance, Laetitia Seguin, David Cheresh. Integrin αvβ3 drives stemness in the pregnant and neoplastic mammary gland. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr C78.
Abstract C83: Nicotine triggers initiation and progression of K-Ras-driven pancreatic ductal adenocarcinoma
Authors: Hermann Patrick C. , Sainz Bruno , Sancho Patricia , Heeschen Christopher
Published: August 2014

Smoking has been identified as a leading risk factor for pancreatic ductal adenocarcinoma. Nicotine is an important active ingredient of tobacco smoke and replacement products, but does not bear carcinogenic properties. While nicotine has been shown to induce proliferation, invasion and metastasis of fully transformed pancreatic cancer cells, its role in pancreatic cancer development and/or progression has not been determined yet. First, our in vivo studies showed a marked acceleration of carcinogenesis in two distinct genetically engineered mouse models for pancreatic cancer. Moreover, nicotine promoted tumor progression as evidence by enhancing the cancer stem cell signature and invasiveness via epithelial-to-mesenchymal-transition. This translated into increased numbers of circulating cancer cells and metastatic lesions. Using two independent model systems, i.e. pharmacological nAChR inhibition and knockout of the alpha7-nAChR, we demonstrate that nicotine activates the pancreatic progenitor compartment resulting in their subsequent expansion and enhanced susceptibility for K-Ras induced pancreatic carcinogenesis. Mechanistically, we found that nicotine-medicated Ca2+ influx induced mitochondrial ROS production and activation of the non-canonical Wnt pathway. Intriguingly, co-treatment with metformin prevented the accelerated pancreatic carcinogenesis and progression independent of AMPK. In conclusion, our findings reveal for the first time that nicotine promotes activation of the pancreatic (cancer) stem cell compartment and subsequently drives K-Ras-initiated pancreatic cancer development and progression.

Citation Format: Patrick C. Hermann, Bruno Sainz, Jr., Patricia Sancho, Christopher Heeschen. Nicotine triggers initiation and progression of K-Ras-driven pancreatic ductal adenocarcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr C83.