bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3337: IL-6 and IL-8 stimulation of breast cancer stem cells contributes to trastuzumab resistance following PTEN deletion
Authors: Hasan Korkaya , Davis April , Kim Gwangil , Quraishi Ahmet A. , Paulson Amanda K. , Chung Susan , D'Angelo Rosemarie C. , Liu Suling , Luther Tahra , Clouthier Shawn G. , Wicha Max S.
Published: June 2012

Recent studies strongly implicated breast cancer stem cells (CSC) in therapeutic resistance and recurrence. Despite the benefits of HER2 targeted therapeutics including trastuzumab for the treatment of HER2 amplified breast cancer, one third of tumors do not respond and resistance develops in patient with chronic exposure. Although the mechanisms mediating HER2 resistance have not been completely elucidated, there is evidence that PTEN deletion plays a role. We have previously demonstrated that HER2 regulates the breast cancer stem cell population through regulation of Akt signaling resulting in Wnt activation. In order to investigate the mechanisms of trastuzumab resistance, we overexpressed HER2 and/or knocked down PTEN in luminal MCF7 and basal SUM159 breast cancer cells. In addition, we knocked down PTEN in two HER2 amplified breast cancer cell lines BT474 and SKBR3. In each case, PTEN knock down increased the CSC population as determined by the Aldefluor assay as well as markedly increasing the production of the cytokines IL-6 and IL-8. Cytokine production was partially mediated through Akt activation of NF-κB. Short term trastuzumab treatment decreased the CSC population in HER2 amplified breast cancer cell lines, an effect that was completely abrogated by PTEN knockdown. Long term trastuzumab treatment of HER2 amplified and PTEN deleted cell lines generated resistant populations that secreted significantly elevated levels of IL-6 and IL-8. In vivo, intrinsically or experimentally amplified HER2 cells with PTEN knockdown were highly tumorigenic and produced metastasis in multiple organs. We previously demonstrated that the Akt inhibitor perifosine is able to reduce CSCs in PTEN-deleted tumors. In order to examine the role of IL-6 and IL-8 in mediating trastuzumab resistance, we treated mice bearing HER2 overexpressing PTEN deleted xenografts with perifosine alone or in combination with an anti-IL-6 receptor and/or anti-IL-8 antibodies. Tumor growth was substantially suppressed by the addition of IL-6 and IL-8 targeting antibodies. These studies suggest that resistance to trastuzumab in PTEN deleted cells may be partially mediated by the activation of cytokine loops involving IL-6 and IL-8. The use of agents which block these cytokine loops may provide a novel approach to overcome trastuzumab resistance.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3337. doi:10.1158/1538-7445.AM2011-3337
Abstract 334: Evaluation of ProEx C (MCM2 and TOP2A), p16 and Ki-67 as biomarkers for cervical carcinoma
Authors: Wang Hong-Wei , Terinate Paul , Gao Youfang , Wei May , Poongothai A.R. , Kalra Krishan L.
Published: June 2012

Background: Cervical cancer is the second most common cancer among women worldwide. Many studies have confirmed a strong correlation between p16 overexpression and high-grade premalignant or malignant lesions of the cervix. A newer biomarker ProEx C has been implicated as a useful indicator for cervical cancer. However, data on comparison between these biomarkers in cervical cancer remain limited. In this study, we investigated the expression of ProExC, p16 and Ki-67 in cervical carcinoma and ovarian tumors as comparison.

Objective: To determine the value of ProEx C combined with p16 and Ki-67 in detection of cervical carcinoma.

Methods: Total of 28 cases of cervical carcinoma biopsies were included in this study, among these one was adenocarcinoma and 27 cases were squamous cell carcinoma type. Ovary tissue microarray (TMA) samples (BioGenex TS-4212) were used for comparison. ProEx C antibody cocktail was prepared from rabbit monoclonal antibodies against minichromosome maintenance protein 2 (MCM2, clone ID: EPR4120) and Topoisomerase II alpha (TOP2A, clone ID: EP1102Y). All tissue samples were examined for expression of p16 and Ki67. Co-localization of ProEx C/p16 and ProEx C/Ki-67 was determined by simultaneous double stain method. Fully automated Xmatrx® system was used for the IHC staining.

Results: Overexpression of ProEx C was found in all 28 cases of cervical carcinoma tissues. All the cancer cells and some other proliferative cell types showed nucleus staining pattern. Upregulated expression of p16 was observed in all 28 cases, with both nucleus and cytoplasmic staining. The p16 staining was limited within those cancer cells. Simultaneous double stain for ProEx C/p16 demonstrated that over 90% of cancer cells co-expressing these two biomarkers. Although Ki-67 staining was also observed in all the cases, a variable portion (less than 50%) of cancer cells was Ki-67 positive. ProEx C/Ki-67 double positive cells were ranging from 20% to 40% of total ProEx C positive cells. Of the 41 ovary tissues from TMA, 35 were ovarian tumor samples and ProEx C positive, 17/35 was p16 positive (48.6%).

Conclusions: 1) ProEx C is a sensitive proliferation biomarker for diagnosis of cancer, which is more sensitive in determining proliferation status than that of Ki-67. 2) p16 is a more specific biomarker for cervical carcinoma than that for ovarian cancer. 3) Combination of ProEx C and p16 may increase the sensitivity and specificity in cervical cancer detection.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 334. doi:10.1158/1538-7445.AM2011-334
Abstract 3341: TGFβ/ TNFα-mediated epithelial-mesenchymal transition generates breast cancer stem cells with a claudin-low phenotype
Authors: Asiedu Michael K. , Ingle James N. , Behrens Marshall D. , Radisky Derek C. , Knutson Keith L.
Published: June 2012

Breast cancer recurrence is believed to be caused by a potently tumorigenic sub-population of cancer cells possessing stem cell attributes of resistance to chemotherapy, radiation and other forms of treatment. Recently, we and others have reported the generation of breast cancer stem cell (BCSC) characteristics by inducers of epithelial to mesenchymal transition (EMT). Both EMT and acquisition of BCSC properties are therefore important steps in cancer progression, although the physiological process by which BCSCs arise in vivo remains unclear. We show here that exposure to TGFβ and TNFα induces a stable BCSC phenotype, characterized by self-renewal, greatly increased tumorigenicity, and increased resistance to oxaliplatin, etoposide and paclitaxel. We further found that the TGFβ/TNFα-derived cells showed downregulated expression of Claudins 3, 4 and 7 and the luminal marker KRT18, demonstrating a shift to the claudin low molecular subtype, a recently identified breast cancer subtype characterized by the expression of mesenchymal and stem cell-associated markers and correlation with poor prognosis. Furthermore, pathway analyses of the generated BCSCs showed deregulation of a number of breast cancer-associated genes and pathways including inflammatory cytokine and receptors, chemokines, homeobox, hedgehog, notch and metastases genes. These results confirm the role of EMT and BCSCs in resistance of breast cancer to conventional chemotherapy and identify novel target genes and pathways for validation as potential therapeutic targets. Our demonstration that stable BCSCs can be produced by specific microenvironmental signals also provides a valuable tool for studying cancer stem cells, as well as a means for screening potential cancer drugs for efficacy of targeting cancer stem cells to prevent recurrence.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3341. doi:10.1158/1538-7445.AM2011-3341
Abstract 3347: Characterization of an epithelial micro-pattern within ducts and lobules of the human breast: The topography of estrogen receptor expression
Authors: Villadsen Rene , Fridriksdottir Agla , Kim Jiyoung , Ronnov-Jessen Lone , Petersen Ole W.
Published: June 2012

The human breast is a unique organ in that it undergoes most of its development after birth under the control of systemic hormones. The adult human breast undergoes cycles of cell proliferation and apoptosis not only during pregnancy but also within the menstrual cycle throughout the reproductive life of women. These highly dynamic changes are thought to rely on the presence of a mammary stem cell population. Recently, we have succeeded in defining a stem cell hierarcy as well as a stem cell zone located to ducts in the normal human mammary gland.

In the present study we have utilized multiparameter cell sortings to isolate two types of progenitors present in the luminal compartment of the mammary gland. One population defines a lineage-restricted progenitor with the capacity of expressing endocrine receptors. The other compartment is enriched for cells with stem cell activity, including the ability to form TDLU-like structures in Matrigel. Further characterization of these populations include testing of expression markers for stem cell activity, lineage-differentiation, anti-apoptotic pathways, as well as finding optimal culture conditions for propagating the cells in vitro.

This may lead to identification of those long-term breast resident(s) that accumulate enough genetic hits for clonal expansion and tumor development, i.e. the cellular origin(s) of breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3347. doi:10.1158/1538-7445.AM2011-3347
Abstract 335: Mutation analysis of KRAS and BRAF genes in sebaceous lesions and keratoacanthomas sporadic or related to hereditary syndrome
Authors: Meireles Sibele I. , Stamboni Merin B. , Crespo Rodrigo , Gomes Marina , Landman Gilles , Coudry Renata A.
Published: June 2012

BACKGROUND: Sebaceous lesions comprises: hyperplasias, adenomas, sebaceomas and carcinomas, which can be sporadic or related to hereditary syndrome. Keratoacanthomas, as sebaceous lesions, can be associated with hereditary cancer, known as Muir-Torre syndrome (MTS), accepted as the presence of those lesions with visceral malignancies, mainly colorectal cancer (CRC). Besides, a subset of MTS shares clinical, pathological and molecular characteristics with hereditary nonpolyposis colorectal cancer (HNPCC). BRAF mutation has already been described in sebaceous hyperplasia but not in CRC in an onset of HNPCC. BRAF oncogene is part of the MAPKinase pathway, as KRAS gene, and both have an important role in cellular proliferation, differentiation and apoptosis. OBJECTIVE: The aim of this study was to evaluate the role of KRAS and BRAF genes in sebaceous lesions and keratoacanthomas in a sporadic setting or related with hereditary syndrome. METHODS: KRAS (codons 12 and 13) and BRAF (V600E) mutations of 52 sebaceous lesions and 42 keratoacanthomas samples was evaluated using Sanger sequencing. 24 (46%) patients had at least one internal malignancy and thus were diagnosed as having MTS. 7 (14%) patients presented clinical or molecular diagnosis of HNPCC. RESULTS: Mutations in KRAS was identified in 7 of 52 cases (14%) of sebaceous lesions and 10 of 42 cases (24%) of keratoacanthomas. BRAF mutation was observed in 2 of 52 cases (4%) of sebaceous lesions and 2 of 42 cases (5%) of Keratoacanthomas. Mutation in both genes occurred in just one sample. There was no statistical significance observed with clinical variables. BRAF mutation was not observed in patients with diagnosis of MTS or HNPCC. CONCLUSION: The results indicate that KRAS and BRAF mutations play a distinct role in carcinogenesis of sebaceous lesions and KRAS a more important event in keratoacanthomas. KRAS mutation was observed in sporadic lesions and also related to hereditary syndrome. However, BRAF mutation was not observed in patients with HNPCC, concordant with observed in CRC with the same origin.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 335. doi:10.1158/1538-7445.AM2011-335
Abstract 3355: Identification of unique tumoricidal genes in rat umbilical cord matrix stem cells
Authors: Uppalapati Lakshmi D. , Ohta Naomi , Zhang Yongqing , Pyle Marla , Becker Kevin G. , Troyer Deryl L. , Tamura Masaaki
Published: June 2012

Umbilical cord matrix stem cells (UCMSC) represent a promising source of therapeutics for various diseases including cancer. We have shown that naïve rat UCMSC significantly attenuate Fisher 344 rat-derived mammary adenocarcinoma (Mat B III) cell proliferation both in vivo and in vitro. To study the underlying mechanisms and genes involved in the Mat B III growth attenuation, we investigated gene expression profiles of naive rat UCMSC alone co-cultured with Mat BIII cells by cDNA microarray analysis. Total RNA was extracted from the naïve rat UCMSC alone and those co-cultured with Mat B III in transwell culture dishes. The comparison of gene expression profiles between untreated and co-cultured rat UCMSC identified five up-regulated (Follistatin (FST), Sulfatase1 (SULF-1), Glucose phosphate isomerase (GPI), HtrA serine peptidase (HTRA1), and Adipocyte differentiation-related protein (ADRP)) and two down-regulated (Transforming growth factor, beta-induced (TGFBI), Podoplanin (PDPN)) candidate genes based upon the following screening criteria: 1) candidate gene expression should show at least a 1.5 fold change in rat UCMSC co-cultured with Mat B III cells; 2) candidate genes encode secretory proteins; and 3) candidate genes encode cell growth-related proteins. Following confirmation of gene expression by real time-PCR, ADRP, SULF-1 and GPI were selected for further analysis. Addition of specific neutralizing antibodies against these three gene products individually or all together in the co-culture of Mat B III cells and 1/20 cell number of rat UCMSC significantly increased [3H] thymidine uptake in the Mat B III cells implying that these gene products are functionally produced under the co-cultured condition and attenuate cell growth. Immunoprecipitation followed by Western Blot analysis demonstrated that these proteins are indeed secreted into the culture medium. We are investigating the siRNA-dependent down regulation of these genes in rat UCMSC to confirm their tumor suppressor function. These results suggest that ADRP, SULF-1 and GPI act as tumor suppressor genes and these genes might be involved in rat UCMSC-dependent growth attenuation of rat mammary tumor. This work was supported by the Kansas State University (KSU) Terry C. Johnson Center for Basic Cancer Research, KSU College of Veterinary Medicine Dean's Fund, NIH P20 RR017686, p20RR1556, R21CA135599, Kansas Bioscience Authority research fund and by the Intramural Research Program of the NIH, National Institute on Aging.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3355. doi:10.1158/1538-7445.AM2011-3355
Abstract 3358: Acquired epithelial-mesenchymal transition synergizes with normal epithelial cells to induce hepatic metastases
Authors: Zubeldia Idoia G. , Bleau Anne-Marie , Gil-Puig Carmen , Vidal-Vanaclocha Fernando , Calvo Alfonso , Lecanda Jon
Published: June 2012

Identification of the required hallmarks for the tumor cells to disseminate to the liver represents an important milestone to delay cancer progression, and consequently to avoid the harmful consequences for patients. Largely unknown, a myriad of cell properties seem to cooperate in a successful metastatic process and in the chemo-/radio- therapeutic resistance. Our aim is to define the intrinsic characteristics of tumor cells that may contribute to epithelial-mesenchymal transition (EMT) in early and late metastatic events. We previously observed that: i) metastatic cells reaching the liver microenvironment display cancer stem features associated with EMT and increased TGFβ1-signaling (Zubeldia et al. Proceedings AACR, 2010; 51, #2304); ii) hepatic secondary tumors are enriched with a subpopulation of cells with a distinctive Sca1+ phenotype and a concurrent increased expression of other cancer stem markers (Zubeldia et al. Proceedings MRS-AACR, 2010; #A105). First, we demonstrated the high tumorigenicity of these metastatic liver-derived cell lines after subcutaneous injection in nude mice, without obvious correlation with their origin regarding TGFβ1-signaling. However, as shown by bioluminescent imaging, some of the novel metastatic liver-derived cell sublines were unable to achieve metastases following intrasplenic injection in C57BL/6J mice. We also noted a differential efficiency of each clone in primary tumor formation in this experimental model. Importantly, we found that co-injection of these cells (isolated from liver metastases) with non transformed hepatocytes (AML12) resulted in a significant increase of metastasis formation. We show an important role of normal cells for metastatic spread in early steps of tumor formation, and suggest the protective activity that the untransformed epithelial cells may have throughout the metastatic progression. We will present the therapeutic implications of our findings for the clinical treatment of carcinomas.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3358. doi:10.1158/1538-7445.AM2011-3358
Abstract 3371: Expression levels of EMT-related genes in hepatocellular carcinoma
Authors: Nagai Tomoyuki , Arao Tokuzo , Matsumoto Kazuko , Kudo Kanae , Hagiwara Satoru , Sakurai Toshiharu , Ueshima Kazuomi , Haji Seiji , Kudo Masatoshi , Nishio Kazuto
Published: June 2012

Epithelial-Mesenchymal Transition (EMT) has been recognized as a cellular process by which epithelial cells undergo mesenchymal phenotype leading to increased motility and invasion in cancer cells. We recently have reported that sorafenib exerts a potent inhibitory activity against the EMT by inhibiting MAPK signaling and SNAI1 expression in hepatocellular carcinoma (HCC). Large-scale clinical data on SNAI1 expression and the prognosis of patients with HCC was recently reported, and the overexpression of Snail and/or Twist was correlated with a worse prognosis. However, it remains largely unclear on clinico-pathological features of other EMT-related genes and whether these genes are overexpressed in HCC compared with paired non-cancer lesion of the liver.

Here, we examined the mRNA expression levels of EMT-related genes including SNAI1/Snail, SNAI2/slug, ZEB1/TCF8, ZEB2/SIP1, TWIST, CDH1/E-cadherin, CDH2/N-cadherin, VIM/vimentin and FN1/fibronectin in HCC. RNA was extracted from frozen surgical HCC samples (n=48) and their paired liver samples (n=14). Real-time RT-PCR amplification was performed. Glyceraldehyde 3-phosphate dehydrogenase (GAPD) was used to normalize the expression levels in the subsequent quantitative analyses. E-cadherin was significantly downregulated in most of HCC (12/14) and those of 5 HCC were markedly downregulated below 25% of paired liver. Interestingly, we found that ZEB1 is tended to be upregulated in HCC, while ZEB2 was downregulated. Regarding EMT-inducible transcription factors, SNAI1, SNAI2, ZEB1, ZEB2 and TWIST, these expression levels were overexpressed in several HCC samples.

In conclusion, our findings indicate that some HCC subpopulation actually undergo EMT via upregulation of SNAI1, SNAI2, ZEB1, ZEB2 and TWIST. Evaluation of clinico-pathological features on these expression and analysis of additional HCC samples up to 100 cases are now under way.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3371. doi:10.1158/1538-7445.AM2011-3371
Abstract 3377: The effect of E-cadherin loss on melanoma formation and metastasis in a conditional mouse model
Authors: Rosenbaum Lara E. , Damsky William E. , Bosenberg Marcus
Published: June 2012

Melanoma claims the lives of thousands of individuals each year despite the development of novel therapeutic agents. The vast majority of these deaths are due to cancer metastasis and prognosis in each case is often difficult to determine. This lack of effective therapy and prognostic indicators emphasize the need for a better understanding of the genetic and phenotypic changes in melanoma formation and progression. One such change may be the loss of E-cadherin, an important molecule in cell-cell adhesion. E-cadherin is downregulated with melanoma disease progression, suggesting that it may function to restrict melanoma invasion and metastasis. Though changes in E-cadherin expression have been suggested to be important in cancer progression in in vitro studies, few have investigated this change functionally in vivo. In order to characterize the role of E-cadherin in melanoma formation and metastasis, we have utilized a well-characterized conditional mouse model combining the Braf V600E mutation with Pten tumor suppressor loss. This model allows us to specifically and reproducibly induce melanoma in mice in a spatially and temporally restricted model. We have combined this model with conditional E-cadherin inactivation in order to evaluate the role of E-cadherin loss on changes in cell morphology and signaling in addition to melanoma formation, progression and metastasis. Loss of E-cadherin significantly decreases survival of mice in the Braf/Pten tumor model and alters the expression of markers of epithelial to mesenchymal transition (EMT). These findings functionally delineate the role of E-cadherin loss in melanoma formation and progression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3377. doi:10.1158/1538-7445.AM2011-3377
Abstract 3378: HO-1 challenges the epithelial mesenchymal transition in prostate cancer
Authors: Gueron Geraldine , Salles Angeles , Labanca Estefania , Coluccio Federico , Navone Nora , De Siervi Adriana , Vazquez Elba
Published: June 2012

Prostate cancer (PCa) is the second leading cause of cancer-associated death in men. Tumorigenesis is highly associated with inflammation. Key mediators of this event may play multiple roles in the etiology of PCa and the onset of its progression. The metastatic spread of PCa cells relies on their ability to undergo EMT acquiring undifferentiated properties, loosing the tight junctions between them, hence becoming more motile and invasive. In this context, heme oxygenase-1 (HO-1), the inducible isoform of the rate-limiting enzyme in heme degradation, emerges as a potential epithelial mesenchymal transition (EMT) modulator counteracting oxidative and inflammatory damage. Here we assessed the expression profile of the EMT markers and the interplay between EMT regulators in androgen sensitive (MDAPCa2b and LNCaP) and insensitive (PC3) PCa cell lines under HO-1 modulation. Our results show that treatment with hemin, a potent and specific inducer of HO-1, increased mRNA levels of E-cadherin, β-catenin, and endoglin. Stable transfection of HO-1 in PC3 (PC3HO-1) also showed a significant increase of these epithelial markers. PC3HO-1 xenografts growing subcutaneously in athymic nude mice showed significant up-regulation of these markers compared to control tumours. Furthermore, using an RT-qPCR-generated gene array we identified the adhesion molecule COL4A3 as a novel downstream target of HO-1. HO-1 modulation limited the metastatic potential of neoplastic cells by up-regulating COL4A3 production. Moreover, a quantitative analysis of cell adhesive forces revealed that HO-1 induction increased PCa cell adhesion to a collagen IV matrix. Taken together these results implicate for the first time HO-1 in the modulation of the EMT and cell adhesion in PCa progression. Targeting EMT program directly or indirectly through HO-1 modulation may represent a novel avenue to decrease tumor bulk and eradicate undifferentiated cells with potential to colonize a rare field.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3378. doi:10.1158/1538-7445.AM2011-3378
Abstract 338: Truncating TP53 mutations have prognostic significance in head and neck squamous cell carcinoma
Authors: van der Plas Marlon , Brakenhoff Ruud H. , Kuik Dirk J. , Buijze Marijke , Bloemena Elisabeth , Snijders Peter Jf , René Leemans C. , Braakhuis Boudewijn Jm
Published: June 2012

Background: TP53 is a key gene in cellular homeostasis and is frequently mutated in head and neck squamous cell carcinoma (HNSCC). There is a variety of TP53 mutations, each with its own biological and clinical implication. Some HNSCC are TP53 wild type, amongst those caused by infection with the human papillomavirus (HPV). Aim of the study was to assess the prognostic significance of TP53 mutations in HNSCC and to identify the most relevant mutation.

Methods: TP53 mutation status was assessed by direct sequencing in 141 consecutive HNSCC treated by surgery with radiotherapy when indicated and with a known HPV-status. The type of mutation was correlated with overall survival in a multivariate two-sided Cox regression analysis with wild type as reference.

Results: HPV infections was found in 12 out of 141 cases (9%). Although a relation between HPV infection and a favorable prognosis was observed, the association was not significant. A TP53 mutation was found in 88 (62.4%) of the carcinomas and was not associated with survival. Tumors with a mutation resulting in a truncated protein (n=36, 25.5% consisting of nonsense, frame shift and splice site mutations), had a significantly worse overall survival (Hazard ratio: 2.54 with 95% confidence intervals of 1.28 and 5.05, p=0.008). Multivariate analysis showed that a truncating mutation is an independent risk factor, adjusted for HPV status. A missense (i.e. non-truncating) mutation did not influence prognosis. Other ways of mutation classification (disruptive vs. non-disruptive, hotspot vs. non-hotspot and DNA-binding vs. non-DNA-binding) were less discriminative and co-factors, including HPV-status were confounding in these associations.

Conclusion: Truncating mutations in the TP53 gene are an important independent predictor for a poor prognosis of HNSCC patients. This patient group is an ideal target population for adjuvant therapy with chemoradiation or viral vector mediated TP53 gene transfer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 338. doi:10.1158/1538-7445.AM2011-338
Abstract 3380: Transient Tgfβ exposure causes persistent transdifferentiation in mouse mammary epithelial cells in vitro and in vivo
Authors: Dunphy Karen A. , Roberts Amy L. , Yan Haoheng , Tao Luwei , Hagen Mary J. , Jerry D Joseph
Published: June 2012

Transforming growth factor beta (Tgfβ) is transiently increased during involution in the mammary gland following a pregnancy and may promote the risk of pregnancy associated breast cancer (PABC). While tgfβ inhibits growth of normal mammary epithelium and has a functional role in restoring the pre-pregnancy architecture of the mammary gland, this cytokine also has tumor promoter function because it promotes epithelial to mesenchymal transition (EMT) and initiates metastatic behavior in tumor cells. We hypothesize that transient Tgfβ exposure, to mimic involution, selects for cells that are susceptible to EMT and increases risk for PABC. We have found that short term 14 day treatment of CDβGeo cells, a mouse mammary epithelial cell line, with Tgfβ (5ng/ml) promotes EMT. These cells are persistently transdifferentiated (pTD) even after withdrawal of Tgfβ. In contrast to the parental CDβGeo cells, the pTD cells have decreased expression of E-cadherin (3-fold, p<0.05) and increased levels of N-cadherin (4-fold, p<0.05). The pTD cells also exhibited a striking increase in motility and invasion in Matrigel (invasion index >3-fold, p<0.01), but there was no difference in proliferation rates between CDβGeo cells and pTD cells. The pTD cells also were strongly tumorigenic when transplanted into cleared mammary fat pads (80% of pTD,TE50=43 days vs <10% of CDβGeo at 80days; p<0.01). Levels of Snail mRNA were also increased in pTD (2-fold;p<0.01) and in the tumors derived from the pTD transplants (>5-fold;p<0.01). In addition, expression of Tgfb2 mRNA was also increased (2.8-fold;p<0.05) in the pTD cells. These results demonstrate that transient exposure to Tgfβ causes persistent transdifferentation with increases in Snail and Tgfb2 expression in CDβGeo cells and suggest maintenance of transdifferentiation through an autocrine positive feedback loop.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3380. doi:10.1158/1538-7445.AM2011-3380
Abstract 3396: Neural stem cells, cancer stem cells and microRNAs: The medulloblastoma paradigm
Authors: Miele Evelina , Ferretti Elisabetta , Po Agnese , De Smaele Enrico , Begalli Federica , Screpanti Isabella , Gulino Alberto
Published: June 2012

Increasing evidence supports the idea of cancer as an aberrant morphogenetic process in which master developmental pathways (e.g. Hedgehog, Hh) are subverted. Stem cells (SC) sustain cell development through proliferation and differentiation events, from cell progenitor transitions until a fully differentiated phenotype. SC with similar properties have been also identified in most cancers. These cancer stem cells (CSC) may represent both the potential “cell of origin” of the tumor and a never ending reservoir responsible for tumor maintenance and progression. A paradigm of altered development as a cause of malignant transformation via aberrant Hh signaling is provided by Medulloblastoma (MB), the most common brain malignancy of childhood, in which also CSC have been described. Besides, microRNAs (miRNAs) have been recently identified as key molecules in the gene expression regulation both in development and in cancer: an altered expression of miRNAs is involved in neoplastic disorders and CSC behaviour.

The overall aims of our work were to exploit the Hh-dependent tumorigenesis process of cerebellar stem/progenitor cells as a paradigmatic model to understand the link between subverted cell development and neoplastic transformation and tumor maintenance. We performed high-throughput miRNAs expression profiling of both neural and medulloblastoma stem cells (NSC, Mb SC). Of note, a number of miRNAs were found differentially expressed with stemness (both in NSC and in CSC). Moreover, we found different pattern of miRNAs expression in Mb SC samples in comparison with the normal counterpart (NSC). These observations suggest the presence of stemness specific and cancer stemness specific microRNA. Differentially expressed miRNAs will be selected for further testing on regulation of signaling pathways involved in the control of stemness and cell development. This study will provide new insight in miRNAs regulation and role in maintenance of the stem cell-like properties of neuronal tumor cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3396. doi:10.1158/1538-7445.AM2011-3396
Abstract 3400: Stem-like tumor cells confer drug resistant properties to mantle cell lymphoma
Authors: Jung HyunJoo , Nami McCarty
Published: June 2012

Hematological malignancies harbor sub-populations of cancer-initiating cells (C-ICs) that play important roles in contributing to tumor initiation, progression and drug-resistance. Mantle cell lymphoma (MCL) is highly refractory to conventional chemotherapy regimens as well as new antibody-based therapeutic interventions.

We recently observed clonogenic cancer-initiating cells in human MCL (MCL-ICs) and showed that MCL initiating activities were enriched in the cells that lack the prototypic B cell marker CD19. We discovered that MCL-ICs are highly tumorigenic and display self-renewal capacities in vivo; in contrast, CD45+CD19+ MCL cells, which constitute the vast majority of cells within the tumors, show no self-renewal capacities and greatly reduced tumorigenicity.

Given the newly appreciated roles of cancer-initiating cells in the drug resistance of cancers, it is critical to investigate whether MCL-ICs play roles in drug resistance of human MCL. We have discovered MCL-ICs were more resistant to several clinically-relevant chemotherapeutic agents in combination or in a single regimen compared to CD45+CD19+ cells. The drug resistance of MCL-ICs was largely due to quiescent properties with enriched ABC transporters. In conclusion, designing novel therapies to kill MCL-ICs may prevent relapse and increase patient survival.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3400. doi:10.1158/1538-7445.AM2011-3400
Abstract 3422: Requirement of the histone demethylase LSD1 in Snail-mediated transcriptional repression during epithelial-mesenchymal transition
Authors: Lin Tong , Ponn Alison , Lu Jianrong
Published: June 2012

Cellular transitions between epithelial and mesenchymal states have crucial roles in embryonic development and tumor metastasis. Members of the Snai1 family of zinc finger transcription factors have emerged as key regulators of epithelial-mesenchymal transition (EMT) and induce EMT in part by directly repressing epithelial markers such as E-cadherin, a gate keeper of the epithelial phenotype. However, the mechanisms underlying Snai1-mediated transcriptional repression remains incompletely understood. Our study shows Snai1 physically interacts with histone demethylase LSD1 (KDM1A) via the repressive SNAG domain located at the N-terminus. Stable over-expression of Snai1 in human mammary epithelial cell MCF10A recruits LSD1 to the E-cadherin promoter and reduce the level of dimethylation of lysine 4 in histone 3 (H3K4m2), a covalent histone modification commonly associated with active promoters. LSD1 is essential for Snai1-mediated transcriptional repression and for maintenance of the silenced state of Snai1 target genes in invasive cancer cells. In the absence of LSD1, Snai1 fails to repress E-cadherin. In cancer cells in which E-cadherin is silenced, depletion of LSD1 results in partial de-repression of epithelial genes and elevated H3K4m2 levels at the E-cadherin promoter, These results underline the critical role of LSD1 in Snai1-dependent transcriptional repression of epithelial markers and suggest that the LSD1 complex could be a potential therapeutic target for prevention of Snai1-dependent EMT and tumor invasion.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3422. doi:10.1158/1538-7445.AM2011-3422
Abstract 3423: The role of PGC1-α and KLF4 in inhibiting the progression of human hepatoma cells
Authors: Chi Chin-Wen , Sung Ming-Ta , Ho Ann-Tin , Lee Chin-Chun , Tu Wei-Shan , Yin Peng-Nein , Yin Pen-Hui , Lee Hsin-Chen , Lui Wing-Yiu
Published: June 2012

Hepatocellular carcinoma (HCC) is one of the most common cancers with high mortality worldwide. Hypoxia is considered as a driving force to trigger the progression of malignancy, such as epithelial-mesenchymal transition (EMT) process, tumor metastasis, and recurrence. Because of the high recurrence rate caused by frequent metastasis and the lack of effective systemic treatment, development of new biomarkers and therapeutic targets for HCC treatment is urgently needed. Loss of E-cadherin is an early and critical step in EMT process and tumor metastasis. Consequently, modulation of the expression of E-cadherin may be a potential way to prevent tumor metastasis. Recently, we have demonstrated that overexpression of peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) not only down-regulated the cyclin D1 expression and inhibited growth of hepatoma HepG2 cells, but also up-regulated the E-cadherin expression and concomitantly down-regulated the mesenchymal marker, and decreased the vimentin expression as well as the migration of HepG2 cells. In this study, we observed a significant increase in the expression level of Kruppel-like factor 4 (KLF4) in HepG2 cells when PGC-1α was overexpressed by adenovirus mediated gene transfer. Using wound healing assay and Western blotting, we further observed increased cell migration and decreased expression of KLF4 in HepG2, Hep3B, and HA22T/VGH hepatoma cell lines under hypoxia condition. Moreover, the KLF4 expression level in HepG2 cells under hypoxia and combined with drug treatment was also examined. We found that treatment of sodium nitroprusside, a nitric oxide donor, can protect HepG2 cells from hypoxia- and glucose depletion-induced cytotoxicity through repressing the KLF4 and Bip/Grp78 expression. After treatment with a cytotoxic dose (1 μM) of doxorubicin, the KLF4 expression of HepG2 cells was decreased under normoxia while it was increased under hypoxia. These results together suggest that PGC-1α may regulate the expression of E-cadherin via KLF4, and the KLF4 expression correlated with the response of HepG2 cells to doxorubicin under hypoxia. PGC-1α and KLF4 may serve as potential targets to inhibit the growth and metastasis of hepatoma cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3423. doi:10.1158/1538-7445.AM2011-3423
Abstract 3424: Slug-mediated epithelial mesenchymal transition in lung cancer cells
Authors: Daisuke Tamura , Arao Tokuzo , Nagai Tomoyuki , Furuta Kazuyuki , Sakai Kazuko , Kudo Kanae , Kaneda Hiroyasu , Aomatsu Keiichi , Fujita Yoshihiko , Matsumoto Kazuko , Kotani Yoshikazu , Nishimura Yoshihiro , Saijo Nagahiro , Nishio Kazuto
Published: June 2012

Epithelial-Mesenchymal Transition (EMT) has been classified as a unique process by which epithelial cells undergo mesenchymal phenotype leading to increased motility and invasion. The aim of this study was to elucidate the biological functions of Slug/Snail2 in lung cancer cells.

We introduced Slug gene into several lung cancer cell line (A549, Ma1, and H1299) and established stable cell lines. Overexpression of Slug clearly mediated the EMT-related morphological changes including the cell scattering and the elongation of cell-shape. Real-time RT PCR and Western blot demonstrated that overexpression of Slug markedly downregulated the mRNA levels and protein levels of E-cadherin, while mesenchymal marker, N-cadherin, fibronectin 1 and vimentin, were upregulated. In addition to these changes, Slug enhanced the cellular migration activity and the cellular anchorage independent growth activity.

Finally, we examined the Slug-mediated EMT on drug sensitivity to several anti-cancer dugs. Interestingly, Slug-overexpressing cells increased the drug sensitivity to only tubulin-binding agents such as vinorelbine, vincristine, and paclitaxel in vitro. Microarray analysis revealed that Slug downregulates tubulin beta 3 or 4 expression. Luciferase promoter assay showed that Slug directly down-regulates tubulin beta 4 expression at the transcription level. These results suggested that Slug-mediated sensitivity to tubulin-binding agents may be involved in expression changes of tubulin beta 3 or 4.In conclusion, we found that overexpression of Slug mediates EMT and change of drug sensitivity to tubulin-binding agents, presumably via downregulations of tubulin beta 3 and 4 in lung cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3424. doi:10.1158/1538-7445.AM2011-3424
Abstract 3426: A signature for epithelial to mesenchymal transition in lung adenocarcinoma
Authors: Schliekelman Mark , Taguchi Ayumu , Wang Hong , Zhang Qing , Wong Chee-Hong , Chin Alice , Gazdar Adi , Hanash Samir
Published: June 2012

Identification of a molecular signature associated with epithelial to mesenchymal transition (EMT) may provide insight into the potential of a tumor to metastasize. To this effect we have undertaken a systems approach to understanding EMT with transcript and proteomic profiling of 30 lung adenocarcinoma cell lines. In-depth proteomic profiling was performed on conditioned media, cell surface and whole cell lysates from lung adenocarcinoma cell lines, allowing characterization as epithelial or mesenchymal based on their levels of E-cadherin and Vimentin, as well as cell morphology. Gene and protein expression from five cell lines that exhibited mesenchymal features were compared with five cell lines that exhibited epithelial features to identify proteins specifically associated with either a mesenchymal or epithelial phenotype. We identified protein signatures specific for mesenchymal or epithelial cells in the whole cell lysates, cell surface and conditioned media, with secreted proteins in the conditioned media representing the most distinct signature based on cluster analysis of protein expression. A much larger number of proteins were specific for epithelial cells than for mesenchymal, suggesting tighter regulation of expression in the epithelial cells. Networks of proteins associated with cell motion, extracellular matrix and growth regulation were identified that were distinct for mesenchymal cell lines while epithelial cell lines exhibited networks of proteins associated with metabolism and cell adhesion. Gene expression analysis of these cell lines supports the observations of tighter gene regulation in epithelial cells as well as the identified protein networks. Identification of a protein signature for EMT provides further understanding of a critical step in tumor progression and has the potential to yield biomarkers to assess likelihood of tumor metastasis in lung adenocarcinoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3426. doi:10.1158/1538-7445.AM2011-3426
Abstract 3428: Coordinated regulation of mesenchymal epithelial transition in the PMC42-LA breast cancer cell line variant
Authors: Hugo Honor J. , van Denderen Bryce JW , Tomaskovic-Crook Eva , Blick Tony , Huang Dexing , Pinto Cletus , Soo Eliza , Fabra-Fres Angels , Haviv Izhak , Goodall Greg , Wong Nicholas , Ackland Leigh , Newgreen Don F. , Waltham Mark , Thompson Erik W.
Published: June 2012

PMC42 cells were derived from a breast cancer pleural effusion and exhibit stem cell-like features when first characterized (Whitehead, Bertoncello et al. 1983; Whitehead, Monaghan et al. 1983). The PMC42-LA subline (Ackland, Michalczyk et al. 2001; Ackland, Newgreen et al. 2003) is distinctly less mesenchymal than parental PMC42-ET cells, but both exhibit EGF- and TGFβ-inducible mesenchymal-like change. Together they provide an ideal model in which to study the regulation of epithelial-mesenchymal plasticity in a breast cancer context. We have assessed in vitro parameters including migration, 3D colony formation and EMT marker expression, and undertook both miRNA profiling (mirVana probe set V1, Ambion) and alternative splice usage (Affymetrix human 1.0 ST whole genome exon arrays) analysis. Several miRNAs were expressed differently in the two sublines and/or up- or down-regulated in response to EMT-inducing treatments. Relative to the mesenchymal ET subline, the, miR-200 family members were elevated in the epithelial LA subline, where a corresponding loss of Zeb1 expression was seen. The LA subline also showed reduced E-Cadherin promoter methylation, and increased methylation of the Zeb1 promoter. Manipulation of the miR 200 family affected the EMT marker expression in these cells, as did Zeb1 suppression with shRNA. Matrigel invasion was also inhibited with Zeb1 knockdown. Additional gene expression changes and alternative splice usage, promoter methylation changes, and miR expression changes are under study. These studies may identify molecules and pathways that are important in cell specification across the epithelial mesenchymal axis, and represent diagnostic and therapeutic targets in breast cancer.

Ackland, M. L., A. Michalczyk, et al. (2001). “PMC42, A novel model for the differentiated human breast.” Exp Cell Res 263(1): 14-22.

Ackland, M. L., D. F. Newgreen, et al. (2003). “Epidermal growth factor-induced epithelio-mesenchymal transition in human breast carcinoma cells.” Lab Invest 83(3): 435-48.

Whitehead, R. H., I. Bertoncello, et al. (1983). “A new human breast carcinoma cell line (PMC42) with stem cell characteristics. I. Morphologic characterization.” J Natl Cancer Inst 70(4): 649-61.

Whitehead, R. H., P. Monaghan, et al. (1983). “A new human breast carcinoma cell line (PMC42) with stem cell characteristics. II. Characterization of cells growing as organoids.” J Natl Cancer Inst 71(6): 1193-203.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3428. doi:10.1158/1538-7445.AM2011-3428