bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 4287: Survival and self-renewing capacity of breast cancer initiating cells during fractionated radiation treatment
Authors: Lagadec Chann H. , Vlashi Erina , Donna Lorenza Della , Meng YongHong , Dekmezian Carmen , Kim Kwanghee , Pajonk Frank
Published: February 2011

Purpose: Recent data indicate a hierarchical organization of many solid cancers, including breast cancer with a small number of cancer initiating cells (CICs) that have the ability to self-renew and exhibit multi-lineage potency. We, and others, have demonstrated that CICs in breast cancer and glioma were relatively resistant to ionizing radiation if compared to their non-tumorigenic counterparts. However, the extent of the remaining self-renewing capacity of CICs after fractions of radiation is currently unknown. We hypothesized that CICs, in contrast with their non-tumorigenic counterparts, not only survive fractions of ionizing radiation but also retain the CIC phenotype as defined by operational means.

Experimental Design: We used two marker systems to identify breast CICs (CD24-/low/CD44high, or lack of proteasome activity) and performed sphere-forming assays after multiple clinical fractions of radiation. Lineage tracking was performed by membrane staining. Cell cycle distribution and RNA content were assed by flow cytometry and senescence was assessed by ß-gal staining.

Results: We demonstrated that irradiated CICs survived and retained their self-renewal capacity for at least 4 generations. We show that fractionated radiation not only spared CICs but also mobilized CICs from a quiescent/G0 phase of the cell cycle into actively cycling cells while the surviving non-tumorigenic cells were driven into senescence.

Conclusions: We conclude that increases in the number of cancer initiating cells after sublethal doses of radiation are potentially of clinically important because the CICs retain increased self-renewal capacity over several generations. Prevention of this process may therefore lead to improved clinical outcome.

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 4287.
Abstract 4291: Imetelstat, a telomerase inhibitor in phase I trials in solid tumor and hematological malignancies, has broad activity against multiple types of cancer stem cells
Authors: Joseph Immanual , Matsui William , LaPorta Caterina A M , Tabori Uri , Kornblum Harley , Herbert Brittney-Shea , Harley Calvin , Tressler Robert J.
Published: February 2011

Numerous studies show that multiple tumor types have rare subpopulations of cells that are initiators of tumor growth, recurrence, and are implicated in tumor metastasis formation. Because of their clonogenic potential, these cells are referred to as tumor initiating cells (TICs) or cancer stem cells. TICs express ABC transporters and can reside in the host in a quiescent state within their preferred niche, which contributes to their resistance to therapies that are effective against bulk tumor cells. Patients having significant objective responses often develop recurrent resistant disease that is thought to be due to TIC outgrowth, and this is thought to contribute to a lack of clinically durable responses. Therefore agents targeting TICs should be included in current therapeutic strategies to assure more effective disease control in patients. Telomerase activation is a common phenotype for the majority of cancers and is essential for maintaining their immortal phenotype. Most tumors having elevated telomerase activity also have shorter telomere lengths than their normal tissue counterparts, and these characteristics make telomerase a promising therapeutic target for cancer. Tumor initiating cells, while distinct from the bulk tumor cell population, share the common traits of increased telomerase activity and relatively short telomeres, suggesting that inhibiting telomerase would be an effective modality for targeting these cells across multiple tumor types. Imetelstat is a potent and specific competitive inhibitor of telomerase currently in phase I clinical trials in solid tumor and hematological malignancies. We have carried out in vitro and in vivo studies demonstrating that imetelstat inhibits telomerase and is effective in targeting TICs from myeloma, melanoma, breast, pancreatic, pediatric glioma, neuroblastoma, prostatic, lung and glioblastoma multiforme tumor types. Our data show that while treatment of TICs with imetelstat is effective, the mechanisms of TIC inhibition may vary depending on the tumor type, and can include antiproliferative effects, induction of apoptotosis or senescence, terminal differentiation, and inhibition of clonogenicity in vitro, as well as inhibition of tumor engraftment and spontaneous metastasis formation in vivo. In summary, imetelstat, a first in class telomerase inhibitor currently in clinical trials, is a promising agent for targeting TICs with broad activity against multiple cancer stem cell types, but the mechanism of inhibition of TICs may vary depending on the specific tumor type.

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 4291.
Abstract 4307: Characterization of a novel lymphoid progenitor population with predictive value in canine non-Hodgkin lymphoma
Authors: Ito Daisuke , Avery Anne C. , Mason Nicola J. , O'Brien Tim D. , Modiano Jaime F.
Published: February 2011

Non-Hodgkin lymphoma (NHL) represents a heterogeneous group of lymphoid tumors divided into more than 25 subtypes. Histological classification and clinical stage are used to predict patient outcomes; however, disease progression is variable even within the same NHL subtype. Cancer stem cells (CSCs) are etiologically important cells that can maintain tumors, or whose frequency may reflect individual tumor biology. In terms of patient care and outcome, CSCs are considered to be resistant to conventional therapies. Thus, CSCs are not only etiologically important, but also might mediate treatment failure and relapse, suggesting they have prognostic impact for cancer. The presence and significance of CSCs or CSC-like progenitor cells in NHL has not been conclusively established. The objective of this study was to evaluate the existence and predictive value of lymphoid progenitor cells (LPCs) in dogs with naturally occurring NHL. We previously reported the use of flow cytometry to prospectively identify and enumerate cells in lymph nodes that co-expressed markers associated with hematopoietic progenitors (CD34, c-Kit, and CD133) and the common leukocyte antigen CD45. The number of these cells was inversely correlated (and predictive) for outcome following standard of care with CHOP-based chemotherapy. We now show that these cells represent an atypical lymphoid population, which harbors progenitor markers and lymphoid differentiation markers found within the B-cell phenotype (CD22+) comprising the malignant population. Furthermore, these cells appear to have clonal antigen receptor rearrangements that are related to the principal rearrangement found in the overall (progenitor antigen-negative) malignant cells. The number of progenitor marker- and CD22-positive cells was significantly greater (P=0.0017) in lymphoma samples as compared to lymph nodes from unaffected control dogs, where cells with this phenotype were present in vanishingly small numbers. Together, our results suggest that LPCs in malignant lymph nodes are not only predictive for survival of dogs with spontaneous NHL, but also may represent the CSC compartment for this disease (i.e., “lymphoma-initiating cells”). To confirm their CSC potential, we have adapted an in vitro culture system and a xenotransplantation model that will allow us to expand and serially transplant these primary canine B-cell lymphomas for more detailed studies. This project establishes a useful large animal (canine) model to test the validity of the cancer stem cell theory in non-Hodgkin lymphoma.

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 4307.
Abstract 4309: Isolation, expansion and molecular characterization of lung cancer stem cells from NSCLC cell lines
Authors: Singh Sandeep , Chellappan Srikumar
Published: February 2011

Lung cancer is the leading cause of death from cancer worldwide. NSCLC represents the most common subtype of lung cancer with the average five-year survival rate is only 16%. The majorities of these tumors are refractory to chemotherapeutics or acquire resistance to the therapy. In addition, most of the patients develop distant metastases even tough their primary tumors are surgically removed. Cancer stem cell hypothesis has emerged as a possible explanation for tumor growth, recurrence after treatment and metastasis in a variety of cancer. This hypothesis suggests that tumors are maintained by the subset of cancer stem cells (CSCs) that has the ability to self-renew and generate the diverse cells that comprise the tumor. While evidence supporting the existence of CSCs has been demonstrated in many solid cancers, it is largely underdeveloped in lung cancer. Here we have isolated cancer stem like cells from NSCLC cell lines either through isolating the side population (SP) cells based on their property to exclude Hoechst 33342 dye or enriched them by cultivating cancer cells in defined serum free medium containing N2-supplement, EGF and bFGF. Cells obtained from both these methods demonstrated higher clonogenic as well as sphere forming ability which is the typical characteristics associated with CSCs. We further characterized these cells for their ability to express progenitor/stem cell marker genes like Oct4, Sox2 and Nanog. Total RNA from SP cells showed higher expression of these genes as compared to main population. Similarly, the expression of Oct4, Sox2 and Nanog was found elevated after culturing H1650, H358, H322 and H292 cells in defined serum free medium for 10 days. Interestingly, CSCs enriched in this condition also showed the loss of E-cadherin expression and consequent gain of mesenchymal proteins like fibronectin and vimentin. Additionally, ABCG2, which is closely associated with the drug resistance and responsible for side population phenotype, was also upregulated in cancer stem like cells enriched from culturing in serum free defined media. In conclusion, results revealed that lung cancer stem like cells could be isolated and expanded from the established lung cancer cell lines by two different methodologies described here. These cells possess the characteristics of both stem cells and malignant tumors. Therefore, further studies towards targeting these cells may result in effective therapy against lung 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 4309.
Abstract 4323: ATP binding cassette transporters modulate both D-luciferin- and coelenterazine-based bioluminescence imaging
Authors: Huang Ruimin , Vider Jelena , Kochetkov Tatiana , Blasberg Ronald
Published: February 2011

Bioluminescence imaging (BLI) of luciferase reporters provides a relatively simple, cost-effective, and extremely sensitive means to image fundamental biological processes in cancer research, including tumor growth, angiogenesis and metastasis. Translocation of D-luciferin (the substrate for Click Beetle Red (cLuc) and Firefly (fLuc) luciferase), and coelenterazine (the substrate for Renilla (rLuc), and Gaussia (gLuc) luciferase), across the cellular membrane could affect BLI intensity in vivo. ATP-binding cassette (ABC) transporters are membrane-bound efflux pumps utilizing the energy from ATP hydrolysis. They are implicated in multidrug resistant phenotypes of tumor cells and may be cancer stem cell markers.

To investigate the effect of ABC transporters on luciferase-based BLI, we generated HEK-293 reporter cells with selective overexpression of different ABC transporters (ABCB1, ABCC1 and ABCG2) and different luciferases (cLuc, fLuc, rLuc and gLuc). In vitro studies showed that BLI signal intensity of intact cells compared to cell lysates decreased 89%, 77% and 75% when ABCG2 was overexpressed in HEK-293 cLuc, fLuc and rLuc reporter cells, respectively. No significant BLI change was observed in HEK-293 gLuc reporter cells with high expression of ABCG2. Overexpression of ABCB1 reduced BLI intensity only in HEK-293 rLuc reporter cells by 51%. ABCC1 overexpression did not affect BLI intensity in any of the HEK-293 reporter cells. These data indicate that ABCG2 affects BLI signal intensity generated from both D-luciferin and coelenterazine, and that ABCB1 affects coelenterazine (but not D-luciferin) signal intensity.

Selective ABC transporter inhibitors, Reversin 121 against ABCB1, MK-571 against ABCC1, and fumitremorgin C (FTC) against ABCG2, were applied in HEK-293 reporter cells with ABC transporter overexpression. Compared with vehicle treatment, FTC increased BLI intensity more than 2-fold in HEK-293 cLuc, fLuc and rLuc reporter cells; Reversin 121 elevated BLI intensity 2.1 fold only in HEK-293 rLuc reporter cells. BLI of xenografts derived from HEK-293 reporter cells with overexpression of ABC transporters confirmed the results of inhibitor treatment in vivo.

These findings demonstrate that ABC transporters can significantly modulate intracellular delivery of luciferase-based substrates, and that endogenous expression of ABC transporters can significantly affect BLI readout, both in vitro and in vivo. In this context, the BLI-based assay can provide a high throughout platform to screen the novel ABC transporter inhibitors for the improvement of antitumor therapy.

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 4323.
Abstract 4326: High-resolution imaging and antitumor effects of GFP(+) bone marrow-derived cells homing to syngeneic mouse colon tumors
Authors: Hart Lori S. , Finnberg Niklas , Dolloff Nathan G. , Rodgers Zachary B. , Dicker David T. , Thomas-Tikhonenko Andrei , El-Deiry Wafik S.
Published: February 2011

Bone marrow-derived cells (BMDCs) are believed to play a significant role in the growth and spread of certain tumors, namely cancers of the breast, brain, lung, and stomach. To date there are limited reports of bone marrow involvement in colon cancer pathogenesis, but such findings have the potential to generate novel treatments for patients with colon cancer. We have established two mouse models (Balb/c and C57/BL6 backgrounds) for imaging BMDCs from whole tumor to single-cell resolution, whereby the bone marrow of lethally irradiated host animals is reconstituted with EGFP-expressing bone marrow cells from matched donors. The bone marrow transplants (BMTs) yield mice with fluorescently labeled bone marrow and BMDCs can subsequently be monitored within a tumor through optical imaging, as well as ex vivo techniques. We have confirmed successful BM reconstitution at six or more weeks following transplantation. At least six weeks after transplantation, surviving Balb/c and C57/BL6 transplanted mice were injected with CT26 mouse colon cancer cells and p53-deficient Ras/Myc-transformed colonocytes, respectively. We have found up to 45% of cells dissociated from the tumors are GFP-positive and we are currently working to identify the various BM lineages represented within these populations. Interestingly, we have found that tumor growth is reduced in BMT animals compared with untransplanted host mice, as well as EGFP-expressing BM donor mice. We are currently working to determine whether an immune response associated with the BMT might account for these apparent anti-tumor effects. It will clearly be important to separate the molecular and cellular (T cells, NK cells, macrophages, etc) basis of the anti-tumor effect of the BMDCs from any pro-tumorigenic effect that could be subverted for therapeutic gain. Additionally, as an extension of our model we are performing orthotopic cecal wall injections in order to determine whether microenvironmental nuances alter BM homing to the colon versus subcutaneous space. It is expected that the identified BMDCs will aid in the development of novel cancer therapeutic and delivery strategies.

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 4326.
Abstract 4330: Effects of isofluran anesthesia on bioluminescence measurements: impact on pharmacological assessment of antitumor activity of chemical entities
Authors: Schnell Christian R. , Arnal Samuel , Becquet Mike , Barbé Stephanie , Garcia-Echeverria Carlos , Cozens Robert
Published: February 2011

Bioluminescence imaging (BLI) has been used for several years in oncology research to quantify tumor growth. In order to allow immobilization during data acquisition, animals are usually anesthetized by isoflurane gas inhalation. However, anesthesia leads to modifications of many physiological parameters, and particularly decreases in heart rate, blood pressure and blood flow, leading to decrease of substrate availability. Thus, it can be postulated that anesthesia will impair bioluminescence read outs. This may in turn profoundly affect interpretation of compound activity based on BLI. We have investigated the difference in BLI measurements performed in conscious and anesthetized animals using subcutaneous xenografts (HCT116 colorectal and U87MG glioblastoma) and orthotopic (U87MG cells injected directly in the brain) models. Moreover, functional tumor vessel mapping and hypoxia stage were obtained using casting technology and HypoxyProbeTM, respectively. Anti-tumor activity of 5-fluorouracil and temozolomide were assessed in the HCT116 xenograft and U87MG orthotopic models, respectively. Our results have clearly demonstrated that in all tested tumor models, tumor growth and efficacy of different compounds were not affected by the regular anesthesia procedure used for bi-weekly BLI assessments. We found a good correlation between caliper and BLI over a wide range of tumor size in conscious mice. When BLI was measured in anesthetized mice, signal intensity dropped significantly up to 70%, impairing the assessment of the antitumor efficacy of 5-FU. A clear correlation to functional tumor vessel density was evidenced. In the U87MG tumors cells implanted intracranialy, we could clearly follow tumor growth over time using BLI readouts. Isoflurane did not impair BLI measurements or the efficacy profile of temozolomide. In conclusion, we can say that BLI measurements in conscious tumor bearing mice offers a better alternative for resolving pharmacologic queries without the confounding effects of anesthesia. Obviously, more extended studies over a wide range of tumor types will be needed to reinforce these conclusions. Moreover, a more quantitative approach to assess vessel density and distribution in the casts using micro-CT technologies would be pivotal.

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 4330.
Abstract 4335: Imaging of cancer stem cells with radiolabeled Hedgehog
Authors: Tworowska Izabela , Li Jessica , Mourtada Firas , Woodward Wendy , Sims-Mourtada Jennifer
Published: February 2011

Recent studies have shown that the majority of early disseminated cancer cells detected in the bone marrow of breast cancer patients have a putative breast cancer “stem cell-like” phenotype. Moreover, activation of stem cell pathways in cancer cells has also been associated with resistance to radiation and chemotherapy. Early detection of these micrometastatic “stem cell-like” cancer cells could allow for earlier commencement of aggressive treatment to minimize relapse and disease spread and to improve therapeutic outcome. However, there is currently no stem cell targeted method to detect this population in vivo. New imaging agents are needed for real-time, non-invasive detection of stem cell pathway activation in micrometastatic disease in breast cancer. The stem cell pathway Hedgehog (HH) is known to regulate cell cycle entry and proliferation of embryonic neural and mammary progenitor cells as well as self-renewal of malignant mammary stem cells. Furthermore, the hedgehog receptor PTCH is overexpressed on cancer stem cells compared to normal mammary stem cells. Therefore, we sought to radiolabel the natural hedgehog ligand, sonic (SHH) with the positron emitter Gallium 68 (68Ga) for detection of cancer stem cells by positron emission tomography (PET). Recombinant SHH ligand was conjugated to the bifunctional chelator DOTA. DOTA-SHH was obtained with a total yield of 45%-60% as assessed by HPLC. DOTA-SHH was further characterized using MALDI-MS, ESI-MS with purity > 90%. The conjugate was radiolabeled with 68Ga, with radiochemical purity of >98% and specific activity of 4.3E+05 MBq/gram (theoretical specific activity = 9.18E+09 MBq/gram) as assessed by ITLC and radioHPLC. 68Ga-DOTA-SHH maintains high receptor binding in breast cancer cells and cellular uptake was correlated with PTCH receptor expression levels. Addition of 100-fold excess cold SHH reduced cellular uptake by approximately 90%. PTCH receptor expression is increased in MCF-7 stem cell-enriching culture conditions (mammospheres) and cellular uptake of 68Ga-DOTA-SHH was approximately 12-fold higher in mammosphere MCF-7 cultures compared to the total cell population. These findings demonstrate that chemical modification and radiolabeling of SHH ligand is feasible. Our studies suggest that 68Ga-DOTA-SHH has potential for molecular imaging of breast cancer by PET. Additionally, our studies suggest that 68Ga-DOTA-SHH can potentially identify aggressive tumors that may be rich in cancer stem cells.

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 4335.
Abstract 4336: Fluorescence laparoscopy for high-resolution pancreatic tumor imaging in an orthotopic mouse model
Authors: Cao Hop S. Tran , Kaushal Sharmeela , Lee Claudia Y. , Snyder Cynthia S. , Thompson Kari J. , Horgan Santiago , Talamini Mark A. , Hoffman Robert M. , Bouvet Michael
Published: February 2011

We report here the development of fluorescence laparoscopy to image green fluorescent protein (GFP)-expressing pancreatic tumors in an orthotopic mouse model.

An orthotopic mouse model of human pancreatic cancer was established by injecting GFP-expressing MiaPaca-2 human pancreatic cancer cells into the pancreas of 6-week old female athymic mice. On post-operative day 14, the animals underwent a diagnostic laparoscopy using both white and fluorescent light. The fluorescence laparoscope was constructed by modifying a standard laparoscopic system in the following manner: a 480-nm short pass excitation filter was placed between the light cable and the laparoscope, and a 2-mm thick emission filter that allows leakage of 1% of the background light was placed between the laparoscope and the camera. The camera and recording system were replaced with a MultiCam 310C (UVP, Upland, CA) that allows variable exposure time and gain setting in the controlling software. The exposure time was set to 110 msec and the gain to 97. A 3-mm 0-degree laparoscope was used in the mice. The mouse's abdomen was gently insufflated to 2 mm Hg via a 22-gauge angiocatheter that was secured via a suture. After fluorescence laparoscopy, the animals were sacrificed, and the identified tumors were collected and processed for histology. The experiments were performed in triplicate.

Fluorescence laparoscopy allowed facile and rapid identification of the bright fluorescent tumors in the pancreatic body. By employing the specific parameters above mentioned, a clear background was visible along with the fluorescent tumor under the fluorescent light mode. This could proffer an advantage in allowing exact localization of the lesions, eliminating the need to flip back and forth between white and fluorescent lighting, under which the background is usually so darkened that it is difficult to maintain spatial orientation.

In summary, the use of fluorescence laparoscopy permits the facile, clear, and rapid identification and localization of tumors that are labeled with fluorescent proteins or other fluorophores. Fluorescence laparoscopy may thus play a useful role in the diagnosis and staging of pancreatic and other aggressive gastrointestinal cancers.

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 4336.
Abstract 4338: The follicle-stimulating hormone receptor: A new tumor vascular endothelial target for imaging and therapy in animal models
Authors: Radu Aurelian , Siraj Ahsan , Vacherot Francis , Thomas Regi , Fujii Dennis K. , Nunn Adrian D. , Ghinea Nicolae
Published: February 2011

The follicle stimulating hormone receptor (FSHR) is a cell surface receptor expressed in the adult human organism only in the ovary and testis by granulosa and Sertoli cells, respectively, and to a lower extent by the endothelial cells (ECs) of gonadal blood vessels. Here we report that FSHR is also expressed by the vascular ECs of some types of tumors in mice and it is accessible to ligands delivered intravenously. We analyzed by immunohistochemistry tumors generated in nude mice by injecting human cell lines and also tumors that occur in transgenic mice that express oncogenes. Consistent FSHR expression by the ECs has been found in mouse tumors generated by the human prostate cell line LNCaP, and in tumors that appear in the polyoma virus middle T oncogene mouse model of breast carcinogenesis. The most robust expression of FSHR by ECs was found in the xenograft tumors generated by injecting the cell line A431 derived from a human epidermoid carcinoma. In a few other tumor types the expression of FSHR by the tumor vascular ECs was less frequent or absent. We investigated also by immunohistochemistry in mouse models the relation between expression by ECs of FSHR and VEGFR2/KDR, a well established marker of angiogenesis. The possibility of using FSHR expressed by tumor ECs for targeted imaging and therapy was explored in mice that carried xenograft LNCaP tumors. We coupled anti-FSHR extracellular domain antibodies to gold particles and perfused the mice with the complexes for 20 minutes. The vasculature was subsequently washed by perfusion and the tissues have been fixed and processed for electron microscopy. Numerous FSHR-gold particles bound to the surface of the tumor endothelium were visible, while there were no particles attached to the ECs in the normal tissues (prostate and lung). The reported data are relevant in the context of our recent finding that FSHR is expressed by ECs in a wide range of human tumors (manuscript submitted). The mentioned animal models can be used to evaluate the potential of FSHR for targeted tumor imaging and therapy based on FSHR ligands delivered intravenously. The mouse models could be also useful for investigating the mechanism of induction of FSHR expression in the tumor ECs and its potential role in tumor growth.

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 4338.
Abstract 4349: The chromosome 17q oncogene LASP1 promotes metastatic dissemination of medulloblastoma
Authors: Remke Marc , Traenka Christopher , Korshunov Andrey , Bender Sebastian , Witt Hendrik , Northcott Paul A. , Scheurlen Wolfram , Reifenberger Guido , Taylor Michael D. , Kulozik Andreas E. , Lichter Peter , Butt Elke , Pfister Stefan
Published: February 2011

Medulloblastoma is the most common malignant brain tumor and one of the leading causes of cancer-related mortality in children. Treatment failure mainly occurs in children harboring tumors with microscopic or macroscopic metastases at the time of diagnosis, which typically show gain of 17q (often based on an isochromosome 17q), a common cytogenetic hallmark of intermediate and high-risk medulloblastoma.

To pinpoint the oncogene(s) targeted by 17q gain, mRNA expression profiling was carried out in primary tumors with and without this indicative aberration and identified LIM and SH3 protein 1 (LASP1) as one of the most up-regulated genes on chromosome 17q in tumors with 17q gain. LASP1 (earlier named MLN50) was initially identified from a cDNA library of nodal breast cancer metastases and is highly expressed in more than 50% of metastatic human breast cancer, ovarian cancer, and hepatocellular carcinoma. In our study in medulloblastoma, a strong association of LASP1 mRNA abundance with 17q gain and metastatic disease at diagnosis was confirmed by quantitative real-time PCR in an independent cohort of 101 primary tumor samples. Protein expression was analyzed by immunohistochemistry in a large cohort of patients (n=207). High LASP1 protein expression was found to be strongly correlated with 17q gain, metastatic dissemination, and inferior overall and progression-free survival confirming our results on transcript level. Furthermore, multivariate analyses revealed LASP1 protein expression as an independent novel prognostic marker for overall survival and tumor progression in medulloblastoma. In vitro experiments in three established medulloblastoma cell lines demonstrate a strong reduction of cell migration and decreased proliferation upon LASP1 knockdown via siRNA, further indicating a functional role for LASP1 in the progression and metastatic dissemination of medulloblastoma.

In conclusion, we have identified LASP1 as an important player in the metastatic dissemination of medulloblastoma which additionally has a high potential to serve as a molecular biomarker for outcome prediction in future prospective studies. Furthermore, LASP1 comprises a promising novel candidate molecule for future targeted therapy approaches in high-risk medulloblastoma.

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 4349.
Abstract 435: Reduction of the invasive phenotype of SNAI overexpressing human breast cancer cells by peptide aptamer-mediated inhibition of SNAI protein functions
Authors: Bailey Charvann K. , Mittal Mukul K. , Misra Smita , Chaudhuri Gautam
Published: February 2011

Two members of the SNAI superfamily of zinc-finger transcriptional repressors: SNAI1 (also known as SNAIL) and SNAI2 (also known as SLUG) are implicated in the induction of aggressiveness and metastatic phenotypes in human breast cancer cells. SNAI1 and SNAI2 are very similar in their amino acid sequences at the C-terminal zinc-finger domains, but the N-terminal repressor domain is somewhat different. SNAI2 has two essential sub-domains, SNAG and SLUG domains, required for its repressor activity. The SNAG domain is also important in SNAI1. We have developed a recombinant protein containing thioredoxin, a tri-repeat of SNAG and SLUG domains of SNAI2 and a membrane translocation motif (MTM; AAVLLPVLLAAP) for the protein to be targeted to the nucleus. We expressed and purified this protein from E. coli using the His-patch thiofusion expression system (Invitrogen). When delivered to MDA-MB-231 and BT549 cells, this aptamer inhibited the functions of the SNAI proteins. The effect of SNAI protein knockdown by the peptide aptamer on the transformed phenotypes of these cells was evaluated by investigating the following parameters: (i) Measurement of doubling time and saturation density by plating cells and performing daily counts. (ii) Evaluation of cellular proliferation by measuring incorporation of 5′-bromodeoxyuridine into logarithmically growing cells. (iii) Determination of anchorage-independent growth in soft agar assays and analysis of the number and size of colonies formed. (iv) Evaluation of the cellular migration in scratch assays and in modified Boyden Chamber/transwell migration assays (directional migration). (v) Measurement of cellular invasion in vitro by using Matrigel-coated chambers. (vi) Assessment of the sensitivity to anoikis by plating cells on poly-HEMA coated plates and determination of cells undergoing apoptosis with propidium iodine staining or annexin labeling and flow cytometric analysis. (vii) Performing 3D culture assays to analyze invasiveness, proliferation or matrix degradation. All these data indicated reduction of the invasive phenotypes of the SNAI protein over expressing highly aggressive and metastatic human breast cancer cells by the peptide aptamer. Wrapsome-mediated targeted delivery of this aptamer alone or with other drugs may be used to reduce the progression of breast cancer. Supported by the DOD-CDMRP IDEA Grant# W81XWH-06-1-0466 and the Susan G. Komen Breast Cancer Foundation grant# BCTR0707627 to GC.

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 435.
Abstract 4352: Using human neural stem cells to model pediatric high grade gliomas: The role of p53, c-myc, and EGFRvIII in neoplastic transformation
Authors: Raabe Eric H. , Maciaczyk Jarek , Kahlert Ulf , Nikkhah Guido , Eberhart Charles
Published: February 2011

Brain tumors are a heterogeneous group of cancers that can arise at multiple locations in the central nervous system. Some brain tumors are restricted to specific anatomical sites, such as medulloblastoma, which is found only in the cerebellum. In the context of this heterogeneity, there are common molecular pathways which are altered across different types of brain tumors. Some of these molecular lesions include inactivation of tumor suppressors such as p53, overexpression of pro-proliferative factors such as c-myc, and alteration of cytokine pathways involving PDGF and EGF. We have isolated neural stem and progenitor cells from multiple sites in the developing human brain, including spinal cord, brain stem, cerebellum, thalamus, and cerebral cortex. These cells can be grown as neurospheres in long term culture, and can differentiate into neurons, astrocytes and oligodendrocytes. To test the hypothesis that these human neurosphere cells can give rise to brain tumors, we infected them with lentivirus encoding hTERT as well as dominant-negative p53, c-myc, and EGFRvIII. The resultant clones derived from cortex, brain stem and spinal cord grow at an increased rate compared to control GFP-infected cells. Interestingly, thalamus-derived cells in the initial analysis do not proliferate rapidly in response to dominant negative p53 and c-myc overexpression, highlighting the potential differences in neural stem and progenitor cell response to oncogenic stimuli. Dominant negative p53 and c-myc overexpressing cells maintain an ability to differentiate in vitro, similar to that observed in human glioblastoma neurosphere lines. Experiments to test the in vitro clonogenic potential and in vivo engraftment of control and infected cells are pending. Our studies suggest that, in contrast to some previous reports, human neural precursor cells can be transformed. They also form the basis for future experiments aimed at creating genetically and pathologically relevant models for pediatric brain tumors.

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 4352.
Abstract 4353: Identification of proteins regulated by mTOR in brain tumors of patients with tuberous sclerosis complex
Authors: Tyburczy Magdalena E. , Kotulska Katarzyna , Pokarowski Piotr , Mieczkowski Jakub , Grajkowska Wieslawa , Jozwiak Sergiusz , Kaminska Bozena
Published: February 2011

Tuberous sclerosis complex (TSC) is characterized by the formation of benign tumors in many organs (mainly brain, heart, kidneys, skin or lungs) and is often associated with epilepsy, mental retardation and autism. Brain lesions include subependymal giant cell astrocytomas (SEGAs), low-grade tumors of a mixed glioneuronal lineage, which are the major cause of morbidity in children and young adults with TSC. The disease is caused by mutations in tumor suppressor genes: TSC1 (Hamartin) or TSC2 (Tuberin) leading to enhancement of mammalian Target Of Rapamycin (mTOR) kinase activity, deregulation of cell growth and tumorigenesis. Signaling via mTOR participates in complex genomic responses but its effectors in the brain are largely unknown. Therefore, we performed first genome-wide expression profiling on SEGAs using Affymetrix Human Genome arrays. We identified differentially expressed specific genes involved in tumorigenesis (up-regulated) and the nervous system development (down-regulated) in SEGAs and SEGA-derived cell cultures when compared to the normal brain or cultured human astrocytes. Out of genes differentially expressed in TSC, 11 were validated by real time PCR on independent tumor samples and 3 SEGA-derived cultures. Immunohistochemistry on paraffin-embedded sections confirmed up-regulated levels of several identified proteins in SEGAs. ANXA1, GPNMB, LTF, RND3, S100A11, SFRP4 and NPTX1 were shown to be mTOR effector genes in SEGA, as their expression was modulated by an mTOR inhibitor - rapamycin in SEGA-derived cell cultures. We are currently investigating the role of ANXA1, GPNMB and S100A11 in regulation of cell viability, migration, adhesion, size and shape of cultured SEGA cells using RNA interference. Furthermore, we observed that combined pharmacological inhibition of mTOR and extracellular signal regulated kinase (ERK) signaling pathways in SEGA cells affected their viability (MTT metabolism test), proliferation (BrdU assay), migration (scratch assay), morphology and size (volume, area and height measured with confocal microscopy). For the first time, we identified genes related to the occurrence of SEGA and regulated by mTOR, and showed an effective modulation of SEGA growth by inhibition of both mTOR and ERK signaling pathways, which could represent a novel therapeutic approach. The study was supported by Ministry of Science and Higher Education grant N N301 263536.

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 4353.
Abstract 4367: Cigarette smoke condensate-induced oxidative DNA damage and its removal in cervical cancer cell lines
Authors: Moktar Afsoon , Vadhanam Manicka V. , Singh Rajesh , Gairola C. Gary , Lillard James W. , Gupta Ramesh C.
Published: February 2011

Increased oxidative stress is implicated in the etiology of cancer. Exposure to cigarette smoke is well documented to increase oxidative stress in smoker tissues and probably plays a role in the incidence of cervical cancer. The cervical pre-cancerous lesions, initiated by HPV infection, generally regress in the absence of the known risk factors such as smoking. The oxidation of deoxyguanosine results in a highly mutagenic and extensively studied oxidative DNA lesion, 8-oxodeoxyguanosine (8-oxodG). The present study was performed to determine i) the effect of cigarette smoke condensate (CSC) on 8-oxodG formation in HPV-transfected cervical cell lines (ECT1/E6 E7); ii) the removal of the oxidative damage from HPV-positive (CaSki), HPV-negative (C33A) and ECT1/E6 E7 cells; and iii) the cell-cycle progression and apoptosis in the CSC-treated ECT1/E6 E7. We found that CSC induced 8-oxodG lesion in a dose- and time-dependent manner in the transfected cervical cell line. A 2.4-fold higher damage was observed in the HPV-positive tumor cell line compared to the HPV-negative cell line. Flow-cytometric and ImageStream (Amnis) analysis indicated that CaSki cells most efficiently removed the oxidative lesion in 48 h (93%). On the contrary, C33A cells did not reveal any significant removal of 8-oxodG up to 48 h. This difference could be explained by the presence of residual p53 activity in CaSki cells while the p53 is mutated in the C33A cell line. ECT1/E6 E7 cell line showed only a modest (22%) removal after 48 h. Interestingly, 8-oxodG was almost completely removed 72 h post-exposure in all the cervical cell lines. Furthermore, a dose-dependent increase in apoptosis was observed in ECT1/E6 E7 cells with an arrest at G0/G1 phase of cell cycle. We conclude that cigarette smoke induces oxidative stress with higher burden in HPV-positive cells; however, HPV exposure may not play a role in the kinetics of 8-oxodG removal (Supported from Agnes Brown Duggan Endowment and, in part, USPHS grant ES-011564).

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 4367.
Abstract 4368: Vitamin E and the green tea active agent EGCG suppress radiation-induced carcinogenesis by different molecular mechanisms
Authors: Mendonca Marc S. , Borgman Anthony , Chin-Sinex Helen , Dhaemers Ryan
Published: February 2011

Treatment induced secondary malignancies after successful radiation and/or chemotherapy cure of primary tumors is a growing area of concern. The identification of chemopreventive compounds that reduce radiation-induced secondary malignancy but are both nontoxic and tolerated with long-term use is a critical need. We investigated the chemopreventive potential and mechanism of action of Vitamin E and EGCG (the active agent in green tea) with the human CGL1 radiation neoplastic transformation assay. The molecularly characterized CGL1 assay allows both alterations of the quantitative neoplastic transformation as well the potential underlying molecular processes of the chemoprevention to be determined. We found long-term treatment with 15 microM EGCG or 50 microM Vitamin E beginning 72 hours after 7 Gy irradiation, significantly reduce radiation-induced neoplastic transformation frequency by a factor of 2.3. We determined that Vit E suppressed radiation-induced carcinogenesis by the induction of a p53 and pro-apoptotic Bax dependent apoptosis in the progeny of the irradiated cells. In addition, we demonstrated that EGCG does not reduce radiation-induced carcinogenesis by increased apoptosis, but rather by the onset of p16 dependent senescence in the irradiated CGL1 progeny. Vit E and EGCG are excellent candidate nontoxic chemopreventive agents for radiation-induced carcinogenesis that work by two distinct molecular mechanisms. We propose that this information should also aid in the development of next generation chemopreventive compounds. These studies were supported by a grant from the DOD awarded to MSM.

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 4368.
Abstract 4371: PI3K/Akt/JNK/c-Jun signaling pathway is a mediator for arsenite-induced cyclin D1 expression and cell growth in human bronchial epithelial cells
Authors: Cai Tongjian , Zuo Zhenghong , Ding Jin , Zhang Dongyun , Li Jingxia , Huang Chuanshu
Published: February 2011

Arsenite exposure is associated with an increased risk of lung cancers. Although efforts have been made, the precise mechanisms of the arsenite-induced lung carcinogenesis remain enigmatic. Aberrant cyclin D1 expression is an early event in carcinogenesis often accompanies human malignancies in the lung. Our previous study has shown that arsenite was able to induce cyclin D1 expression in human keratinocyte HaCat and mouse epidermal Cl41 cells to promote cell cycle transition, cell proliferation and transformation, which accounts for its ability to induce skin carcinogenesis. However, the role of Cyclin D1 underlying the arsenite-induced human lung carcinogenesis remain elusive. In the present study, arsenite exposure induced the cell cycle transition, resulting in growth promotion of human bronchial epithelial cells. The promoter activity and the expression of cyclin D1 were augmented in response to arsenite treatment. To further evaluate the effect of cyclin D1 in arsenite-induced cell proliferation, a cyclin D1 siRNA construct was stably introduced into Beas-2B cells. The siRNA blocked the induction/expression of cyclin D1. It has been reported that JNKs mediate the cyclin D1 expression in hematopoietic cells. Therefore, we investigated the potential contribution of JNKs to cyclin D1 expression induced by arsenite. Our results strongly suggest that JNK1 is a major kinase responsible for maintaining the basal level of C-Jun phosphorylation, and both JNK1 and JNK2 are critical for arsenite-induced C-Jun phosphorylation. Moreover, using a loss of function mutant Dp85 or DN-Akt, we demonstrated that the PI-3K/Akt pathway was involved in arsenite-induced upregulation of cyclin D1 and cell proliferation. The introduction of Dp85 or DN-Akt into the cells also inhibited JNKs activation as well as c-Jun phosphorylation, while the growth promotion induced by arsenite was significantly inhibited by the PI3K inhibitor Ly294002 and JNK inhibitor, or by over expression of DN-Akt. Overall, our data suggest a signaling pathway of PI-3K/Akt/JNK/c-Jun/cylin D1 signaling in response to arsenite in human bronchial epithelial cells, which leading to the growth promotion.

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 4371.