bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 4289: Early study on LGR5/GPR49 molecule as a potential colon cancer stem cell target for the antibody conjugated drug treatment
Authors: Mao Weiguang , Tien Janet , Goldenberg David , Stawicki Scott , Vij Rajesh , Xia Xiaoling , Hongo Jo-Anne , Ross Sarajane , Kozak Kathy , Firestein Ron , Wu Yan , Spencer Susan , Polakis Paul 
Published: February 2011

Abstract
LGR5 (GPR49) is a Wnt pathway downstream target gene. It has already been confirmed that LGR5 gene is up regulated by APC or β-catenin mutation. LGR5 has recently been identified as a biomarker on the human and murine intestinal or colon stem cells. Our gene expression data shows that LGR5 is highly expressed in colon cancer, with minimal expression in normal tissue. Our strategy in this project is to eliminate tumor stem cells by drug conjugated antibody. Our goal is to find a tumor stem cell marker and develop antibody to target the tumor stem cells. Here we developed and characterized both anti-LGR5 phage and monoclonal antibodies by multi molecular techniques. We finally focus on one phage antibody (YW353) and three monoclonal antibodies (2H6, 3G12 and 8E11) as therapeutic drugs for further study. We evaluated antibody drug conjugate (ADC) in vitro and in vivo with different animal tumor models derived from cell lines and human tumor explants. Good efficacy was observed in these animal models following a single dose of 5mg/kg. Conclusion: LGR5 is an attractive colon cancer target for the administration of anti-LGR5 ADC in human cancer. More in vivo models will be tested to confirm the efficacy and evaluate safety.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4289.
Abstract 4294: Differentiated colorectal cancer cells protect tumor-initiating cells from irinotecan
Authors: Emmink Benjamin L. , van Houdt Winan J. , Vries Robert G. , Hoogwater Frederik J.H. , Jimenez Connie R. , Clevers Hans , Rinkes Inne H.M. Borel , Kranenburg Onno 
Published: February 2011

Abstract
Normal colon tissue stem cells drive tissue turnover by generating daughter stem cells and a rapidly proliferating pool of progenitor cells that give rise to differentiated cell types with specialized functions. This functional hierarchy is preserved in colon tumors in which a tumor-initiating cell (or cancer stem cell) compartment drives the formation of proliferating and differentiated cell types with reduced tumorigenic potential. Normal colon stem cells possess a variety of resistance mechanisms that allow them to endure a lifetime of genotoxic insults. By inheriting these traits, tumor-initiating cells (TIC) are thought to be endowed with an intrinsic resistance to chemotherapy. However, the relationship between chemo-resistance and tumor-initiating potential in colon tumors is poorly understood.
We studied this relationship using a series colonosphere cultures isolated from freshly resected primary colon tumors and liver metastases. These cultures are highly enriched for TIC, based on their high clone and tumor-forming potential and expression of the stem cell marker ALDH1. The TIC-enriched cultures display resistance to the toposomerase I inhibitor irinotecan. However, drug resistance is mediated by a small subpopulation of non-tumorigenic differentiated ALDH1-negative cells expressing the drug efflux pump ABCB1. ABCB1 is localized to the brush border of cells at the colonosphere periphery and of cells forming intra-spheroid tubules. In human colorectal liver metastases ABCB1 is predominantly localized to the luminal side of differentiated tubule-forming cells. These ABCB1 drug-resistant cells are proliferation-competent but unable to initiate tumor formation. Conversely, tumor-initiating cells are ABCB1-negative and drug-sensitive, but could generate non-tumorigenic drug-resistant offspring in vitro and in tumor xenografts.
Our work shows that colorectal tumor-initiating cells do not display intrinsic resistance to irinotecan, most likely because they are derived from a normal stem cell population that does not express ABC transporters. Tumor-initiating cells generate a protective shield of drug-resistant ABCB1-positive offspring. Furthermore, the preservation of tumor-initiating capacity following irinotecan exposure requires the cooperative action of drug-sensitive tumor-initiating cells and their drug-resistant differentiated offspring.
Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4294.
Abstract 4295: The combination of a novel anti-delta-like 4 ligand (DLL4) antibody with irinotecan inhibits growth of Kras-mutated colorectal tumors
Authors: Fischer Marcus , Yen Wan-Ching , Lewicki John , Gurney Austin , Hoey Timothy 
Published: February 2011

Abstract
Kras mutations in colorectal cancer (CRC) are associated with clinical resistance to treatment with the epidermal growth factor receptor (EGFR)-targeted monoclonal antibodies. It has been suggested that cancer stem cells drive tumor growth and progression and are preferentially resistant to many current therapies. Delta-like 4 ligand (DLL4) is an important component of the Notch signaling pathway which is known to mediate stem cell self-renewal and vascular development. We have recently demonstrated that inhibition of human DLL4 in the tumor reduced cancer stem cell frequency, whereas inhibition of mouse DLL4 resulted in hyperproliferation of the tumor vasculature (Cell Stem Cell, 5:168-177, 2009). The goal of the present study is to extend the utility of anti-DLL4 in treatment of mutant Kras CRC. Consistent with clinical findings, mutant Kras colorectal xenograft tumors were generally insensitive to EGFR-targeted monoclonal antibody cetuximab and addition of anti-DLL4 did not further enhance cetuximab-mediated anti-tumor effect. In contrast, anti-DLL4 plus irinotecan was equally efficacious against both wild type and mutant Kras colon tumors. Gene expression analysis showed that anti-DLL4 affected vascular-related genes in the stroma and Notch target genes in the tumor and stroma. Further analysis of mutant Kras tumors indicated that anti-DLL4/ irinotecan combination produced a 5-fold decrease in colon cancer stem cell frequency compared to control antibody treated group. In conclusion, our findings provide a rationale for targeting cancer stem cells and tumor vasculature through inhibition of the DLL4/Notch signaling for treatment of CRC patients with Kras mutation.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4295.
Abstract 4296A: Myeloproliferative disease induced by leukemogenic Ptpn11 (Shp-2) phosphatase arises from hematopoietic stem cells
Authors: Xu Dan , Wang Siying , Yu Wen-Mei , Chan Gordon , Araki Toshiyuki , Bunting Kevin D. , Neel Benjamin G. , Qu Cheng-Kui 
Published: February 2011

Abstract
Germline and somatic gain-of-function (GOF) mutations in the tyrosine phosphatase PTPN11 (SHP-2) are associated with juvenile myelomonocytic leukemia (JMML), a clonal myeloproliferative disease (MPD) of early childhood. However, the mechanism by which PTPN11 mutations induce this disease is not fully understood. Here we report that the germline mutation Ptpn11D61G increases mouse hematopoietic stem cell (HSC) activity, as evidenced by accelerated cycling, increased stem cell pool, enhanced self-renewal, and elevated short-term and long-term repopulating capabilities. More importantly, the MPD is reproduced in primary and secondary recipient mice transplanted with Ptpn11D61G mutant marrow cells or sorted Lineage- Sca-1+c-Kit+ cells, indicative of the long-term stem cell origin of the disease. The leukemogenic effect of Ptpn11D61G mutation appears to be attributed to enhancing cytokine signaling. Furthermore, HSC homeostasis disrupted by Ptpn11D61G mutation is partially restored by deletion of Gab2, an important interacting protein/target of SHP-2. MPD phenotypes are markedly ameliorated in Ptpn11D61G/+/Gab2−/− double mutant mice. Together, these studies suggest that SHP-2 associated JMML arises from HSCs and that targeting SHP-2/Gab2 mediated signaling in stem cells may be useful for the treatment of this disease.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4296A.
Abstract 4304: Malignant melanoma cells with aggressive properties are common and not distinguishable by proposed markers for cancer stem cells
Authors: Prasmickaite Lina , Engesæter Birgit , Skrbo Nirma , Oliver Nina K. , Engebråten Olav , Suo Zhenhe , Aamdal Steinar , Fodstad Øystein , Mælandsmo Gunhild M. 
Published: February 2011

Abstract
In malignant melanoma, conflicting results have been reported regarding the presence of exclusive cells with enhanced aggressive properties, so called cancer stem cells (CSC), raising a doubt whether melanoma follows a CSC model and is hierarchically organized. By characterizing melanoma cells from short-term cell cultures, xenografts and patient biopsies, we aim to collect further evidence either to: i) support the existence of distinct CSC-like subpopulations, or ii) strengthen a notion about the common presence of cells demonstrating aggressive behavior and lack of cellular hierarchy in melanoma. By using individual-cell assays, we have shown that a large fraction (up to 60 %) of random single melanoma cells display high clonogenicity and self-renewal i.e. properties associated with tumorigenic potential. In search for a marker for such clonogenic/tumorigenic cells, we found that melanomas often harbor a large distinct subpopulation with elevated activity of Aldehyde Dehydrogenase (ALDH), a proposed marker for CSC-like cells in some hierarchically organized cancers. Interestingly, ALDH activity in melanoma patient biopsies seemed to correlate to the expression of melanoma-associated-antigen, HMW-MAA, which is linked to tumor progression. Furthermore, in vivo ALDH+ melanoma cells could convert to ALDH−, while the opposite conversion was rare, indicating a certain “cellular hierarchy” with respect to the ALDH phenotype. However, comparison of ALDH+ and ALDH− cells revealed that both subpopulations are highly clonogenic, tumorigenic and resistant to drugs proposed for melanoma therapy, DTIC and HGS-ETR2. This suggests that in malignant melanoma, ALDH, likewise earlier investigated “surface markers” of CSCs, does not distinguish cells with enhanced biological aggressiveness. In conclusion, melanoma cells exhibiting properties linked to aggressive phenotype are common and not restricted to subpopulations expressing proposed “CSC markers”, which contradicts the traditional view of CSCs.
Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4304.
Abstract 4306: Functional role of CD133 in glioblastoma multiforme
Authors: Bandopadhyay Gagori , Grabowska Anna M. , Coyle Beth , Watson Susan A. 
Published: February 2011

Abstract
Introduction: Glioblastoma multiforme (GBM) is a cytologically malignant tumour of the central nervous system, associated with poor prognosis and fatal outcome (5 year survival, &lt;6%). Such tumours are believed to be initiated and maintained by a subpopulation of cells, which resemble normal adult stem cells. Cancer stem cells (CSCs), may contribute to the chemo-/radio-resistance exhibited by these tumours and can be identified using the immunocytochemical marker CD133. This pentaspan membrane protein is associated with increased tumorigenicity, chemo-/radio-resistance and poor prognosis. In this study we investigated the functional role of CD133 in the progression of GBM.
Methods: CD133-specific siRNA and siPORT-Amine transfection reagent were used to achieve transient knockdown of CD133 in GBM cell lines. Gene and protein expression were measured over time using real-time PCR and FACS, respectively. GBM cell lines were cultured in 1% oxygen to induce hypoxia. Transient knockdown of hypoxia-inducible factors (HIF) was also achieved using HIF-specific siRNA, in hypoxic conditions. Biological functions of CD133 were assessed by performing wound-healing assay to investigate migration; MTT to measure the rate of proliferation; neurosphere formation potential to assess tumorigenicity; and etoposide drug challenge to assess chemo-resistance.
Results: CD133-specific siRNA successfully knocked down gene expression of CD133 (85% knockdown; p&lt;0.0001 at Day 3 post transfection; n=3). Consequent downregulation in protein expression was also confirmed (p&lt;0.05; n=1). CD133 knockdown was correlated to susceptibility to chemotherapeutic agents, migration, proliferation and tumorigenicity. Hypoxia upregulated CD133 expression by 4-fold (p&lt;0.0001) compared to cells cultured in normoxia. Knockdown of hypoxia inducible factors resulted in the downregulation of CD133 in hypoxia, at 48hrs post transfection. In GBM cell line U251, HIF1-α and HIF2-α knockdown significantly downregulated CD133 gene expression (HIF1-α = 40% downregulation; HIF2-α = 60% downregulation; p&lt;0.001); HIF2-α downregulated CD133 significantly more than HIF1-α (p&lt;0.01), when compared to control negative siRNA.
Conclusion: CD133 knockdown alters biological properties of GBM cells. Furthermore, hypoxia increases CD133 expression in GBM cells, mediated by HIF-1α and HIF-2α. This of particular importance in view of the hypoxic nature of GBMs, which suggests that hypoxia aids survival of cancer stem cells, rendering these tumours resistant to therapy.
Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4306.
Abstract 4312: Identification of putative stem cell markers of CD133 and CD44 in human ovarian cancer specimens and ovarian cancer cell lines
Authors: Sun Guiqin , Meng Fanliang , Li Zhong , Zou Changping , Brewer Molly A. 
Published: February 2011

Abstract
Objective: Ovarian cancer may arise from a subpopulation of CD133+ 44+ cells, which are self-renewing tumor-initiating cells.
Materials and Methods: We investigated the tumorigenicity of the cell line A2780 which is CD133high44low, the cell line A2780 with siRNA against CD133 (CD133low44low), and human ovarian cancer cells from ascites, from primary ovarian cancer, and from metastatic ovarian cancer (CD133 high/CD44high) harvested from patients at the time of surgical cytoreduction in ultra low attachment plates in serum free medium. Spheroids from each of these sources were used to test their tumorigenicity in SCID mice.
Results: Cells from A2780 cell line (CD133 high/CD44low) formed tumors in SCID mice in 2 months but silencing CD133 with siRNA CD133 (CD133 low/CD44low) inhibited tumorigenicity in SCID mice and retarded but did not prevent spheroid formation. Spheroid cultures of ascites, primary ovary, and metastasis (CD133 high/CD44high) are capable of inducing primary ovarian tumors and metastatic tumors in SCID mice in 2 months compared to 4-6 months in sorted, non-spheroid cells.
Conclusions: The data suggest that CD133 expression is necessary for tumorigenesis in the A2780 cell line but not for spheroid formation. Our data also suggests that spheroids which are CD133 high/CD44high from human tumor recapitulate ovarian cancer in women. These novel in vivo and vitro models may offer useful tools to develop therapies targeted to ovarian cancer.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4312.
Abstract 432: Expression of PITX2 is correlated with invasiveness in breast cancer cells and its downregulation reduces invasive potential
Authors: Pillai Sreeraj G. , Dasgupta Nupur , Fleming Timothy P. , Watson Mark A. , Aft Rebecca 
Published: February 2011

Abstract
Objective
We have previously found that PITX2 expression in the bone marrow (BM) of women newly diagnosed with breast cancer correlates with the development of distant disease. PITX2 is not expressed in the BM of normal volunteers, and thus the source of PITX2 is likely to be disseminated tumor cells which lodge in the bone marrow. PITX2 plays a well-defined role in development. This study was conducted to understand the role of expression of PITX2 in the breast cancer phenotype.
Experimental procedures
PITX2 has three different transcript variants. The RNA expression level of each transcript variant was determined by qRT-PCR using specific primers designed for each isoforms in a variety of breast cancer cell lines. PITX2 was stably silenced using shRNA lentiviral constructs against all isoforms of PITX2 (Sigma, St. Louis) and selecting with puromycin. Individual clones were selected and tested for PITX2 expression. Those cells with near total knockdown of the gene were used for matrigel invasion assays using manufacturer's protocols. Briefly, about 3 × 104 cells were suspended in growth factor free media and added to each well of invasion chamber and complete growth medium was added to the lower chamber as chemoattractant. The number of cells which invaded was counted at 24h and 48h after seeding. Control cells included empty vector, a non-targeting sequence, and shRNA against the unrelated gene, Beta 2- Microglobulin. The number of invasive cells were counted from five different fields from each well and tallied. Percentage invasion was calculated as the number of cells passed through the Matrigel to the total number of cells before harvest. All experiments were repeated three times.
Results
PITX2 isoforms A and B were found to be expressed in the invasive cell lines MDA MB 231 and C1A1 while none of the isoforms were expressed in non-invasive cell lines MCF7 and MCF10A. In matrigel invasion assay, the knockdown of PITX2 substantially reduced invasiveness compared to the controls. There was a 63.8 % reduction in invasion in PITX2 deficient cells at 24 hrs and 72.6 % reduction at 48 hrs compared to the parental MDA MB 231 cells.
ConclusionPITX2 is expressed in breast cancer cell lines which have the ability invade and is not expressed in cell lines which cannot invade. Silencing of PITX2 in breast cancer cell lines abrogates the ability of breast cancer cells to invade. These findings combined with our clinic data suggest that PITX2 plays an important role in the invasiveness of breast cancer.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 432.
Abstract 4329: In vivo visualization of epithelial-mesenchymal transition in real time using a rapidly tuneable E-cadherin
Authors: Leong Hon Sing , Lizardo Michael M. , Nambiar Shruti C. , Ablack Amber , Kim Daero , Chambers Ann F. , Lewis John D. 
Published: February 2011

Abstract
The transformation of benign tumour cells to invasive, metastatic tumour cells involves the dynamic redeployment of factors involved in cell adhesion and motility collectively known as epithelial-mesenchymal transition (EMT). While the loss of E-cadherin localization at cell-cell junctions is a hallmark feature of EMT, the impact of E-cadherin re-expression and modulation in metastatic cancer cells at distinct steps of the metastatic cascade has not been explored. To address this, we developed an intravital imaging approach that allows us to visualize changes in behaviour of highly metastatic MDA-MB-231-LN breast cancer cells in real time using a dynamically tuneable form of E-cadherin. Here, we show that upon induction of E-cadherin in vivo, cell-cell adherens junctions begin to appear within 30 minutes, concurrent with the accumulation of plasma membrane-localized E-cadherin and the retraction of tumour cell protrusions and the induction of a rounded epithelial-like morphology. Furthermore, subsequent depletion of E-cadherin results in a rapid reversion to the mesenchymal morphology. These studies demonstrate that E-cadherin is sufficient to induce a rapid mesenchymal to epithelial transition in vivo, and that sustained E-cadherin expression is required to maintain this less invasive morphology.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4329.
Abstract 4345: Proteasome inhibitor, bortezomib, inhibits cell proliferation and induces apoptosis of medulloblastoma cells
Authors: Yang Fan , Jove Veronica , Chang Shirley , Hedvat Michael , Liu Xiangli , Yen Yun , Jove Richard 
Published: February 2011

Abstract
Medulloblastoma is the most common brain tumor in children. Proteasome inhibitors have been reported to inhibit cell proliferation and survival in a variety of tumor cells. Bortezomib (Velcade), an inhibitor of the 26S proteasome, has been approved by FDA to treat multiple myeloma. Here, we investigated effects of bortezomib on human medulloblastoma cells. Bortezomib inhibited cell proliferation and induced apoptosis of Daoy medulloblastoma cells in a time- and dose-dependent manner. Significantly, a relatively low dose of 10 nM bortezomib effectively inhibited the viability of Daoy cells within 48 h. Bortezomib increased the release of cytochrome C to cytosol, resulting in activation of caspase-9 and caspase-3, and cleavage of poly(ADP-ribose) polymerase (PARP). Caspase inhibitor (Z-VAD-FMK) could rescue tumor cells from the cytotoxicity of bortezomib on both cell proliferation and survival. Bortezomib increased expression of the pro-apoptotic protein, Bak, and cleavage of the anti-apoptotic protein, Mcl-1. In addition, bortezomib increased the expression of p21Cip1, a negative regulator of cell cycle progression. Bortezomib also induced the accumulation of phosphorylated I[[Unable to Display Character: &#312;]]Bα in Daoy cells, resulting in inhibition of NF[[Unable to Display Character: &#312;]]B signaling. MG-132, another proteasome inhibitor, had similar effects on Daoy cells. Moreover, bortezomib inhibited the growth of human medulloblastoma cells in a mouse xenograft model. Our data suggest that proteasome inhibitors are promising drugs for the treatment of pediatric medulloblastomas.
Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4345.