bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1394: Pro-apoptotic and anti-tumorigenic effects of a naturally occurring proteasome inhibitor on hormone-refractory prostate cancer
Authors: Karnak David , Dai Yao , DeSano Jeffrey T. , Tang Wenhua , Ljungman Mats , Lawrence Theodore S. , Xu Liang
Published: February 2011

A major mode by which cancer cells evade death is by an acquired ability to suppress apoptosis. In hormone refractory prostate cancer, the overexpression of pro-survival/anti-apoptotic proteins results in resistance to chemo- and radio-therapy. Hence, developing co-therapies that sensitize cells to standard treatment regimens by overcoming this apoptotic block could improve treatment outcomes in advanced prostate cancer. The naturally occurring proteasome inhibitor celastrol has been previously reported to inhibit DNA damage processing and synergize with radiotherapy to kill PC-3 cells. To further explore the mechanism by which celastrol might potentiate cell death, several lines of questioning were explored. First, the open question regarding whether or not celastrol inhibits DNA damage repair, not simply processing, was tested in the comet assay. The tail moments measured in cells treated with celastrol, irradiated and allowed to recover were significantly greater than those in untreated cells, indicating that DNA damage repair was inhibited. In other experiments, cells treated with celastrol displayed an increased expression of the pro-apoptotic, BH3 only protein Noxa. This correlated with an increase in apoptotic cell death which was further augmented by ionizing radiation treatment. The pro-survival protein NFkB is tightly controlled by IkB-alpha binding. Proteasome inhibition can suppress the pro-survival activity of NFkB by decreasing the turnover of IkB-alpha. Indeed, IkB-alpha was found to accumulate in celastrol treated cells. Further, NFkB target gene activation was markedly reduced. To test the feasibility of celastrol treatment in animals, the PC-3 xenograft model in the athymic nude mouse was employed. When celastrol was combined with radiotherapy, tumor volume decreased, apoptosis increased, angiogenesis decreased, and NFkB target gene mRNA levels were found to be lower. Taken together, these data show that celastrol sensitized PC-3 cells to radiation both in vitro and in vivo by impairing DNA damage repair and augmenting apoptosis through suppressing NFkB activation and increasing the protein levels of Noxa. Celastrol may hold promise as a co-therapy with radiation for the treatment of hormone-refractory prostate 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 1394.
Abstract 1396: FGFR1-induced radioresistance of Panc02 pancreatic tumor cells is decreased by SSR128129 treatment in vitro and in vivo
Authors: Tardy Claudine , Gueguen Genevieve , Mazoyer Sandrine , Morin Gaëlle , Planel Severine , Herbert Corentin , Toulas Christine , Moyal Elisabeth Cohen-Jonathan , Schaeffer Paul , Bono Françoise
Published: February 2011

We have previously established the important role of FGF-2 pathways in tumor cell radioresistance. Although radiotherapy is commonly used in the treatment of pancreatic carcinomas which are known to express FGF and FRGFR, the role of FGFR pathways in radioresistance of pancreatic tumor has not yet been studied. We established a new syngenic mouse model of orthotopic pancreatic xenograft of Panc02 cells transfected with hFGFR1-receptor (Panc02-FGFR1). Whereas the in vitro radioresistance of the parental cell line (Panc02) was not affected by the addition of the specific FGF-receptor antagonist SSR128129, Panc02-FGFR1 radioresistance was significantly decreased by treating cells with SSR128129 (1 µM) 4 hours before irradiation (mean inactivation dose [MID] was 6.1±0.2 Gy in control PancO2-FGFR1 versus 4.2±0.2 Gy in SSR128129 treated cells, P<0.001). Orthotopic injection of Panc02-FGFR1 cells in syngeneic C57B6 mice led to rapid growth of pancreatic tumors. While SSR128129 (30 mg/kg/d) was ineffective on the tumor growth, this compound significantly decreased microvessel density in Panc02-FGFR1 tumors (104.7±14.6 vs 136.6±10.3 vessels/field, P<0.001). Local irradiation (2×2.5 Gy) of tumor-bearing animals previously treated for 1 week with SSR128129, led to a strong decrease of tumor size (40% decrease, P<0.05) one week after radiotherapy, whereas the tumor size of untreated animals was not affected by irradiation. The effect of SSR128129 on microvessel density was not affected by radiotherapy. Together, these data show that inhibiting FGFR pathways leads to a major radiosensitization of pancreatic tumors in vitro and in vivo.

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 1396.
Abstract 1402: Molecular basis for soy isoflavone genistein in the prevention of posttreatment recurrence of neuroblastoma
Authors: Veeraraghavan Jamunarani , Madhusoodhanan Rakhesh , Natarajan Mohan , Herman Terence S. , Aravindan Natarajan
Published: February 2011

Clinical and laboratory evidence suggests that neuroblastoma contain populations of rapidly proliferating clonogens that survive chemoradiation or conventional radiotherapy leading to radioresistance. To that note, radioresistance could be associated with survival advantage resulting in clonal selection and tumor re-growth. Recently, we demonstrated that IR activates NFκB that enhances cell survival by switching on genes that attenuate apoptosis. Coherently, studies have demonstrated Genistein (GEN) inhibits NFκB and radiosensitizes cancer cells. In this study, we investigated the functional mechanistic regulation of NFκB mediated survival advantage and, delineated the efficacy of GEN in this setting. Human SH-SY5Y, IMR-32 and SK-N-MC cells exposed to 2Gy (IR) with or without GEN (100μM) were examined after 15min through 72h. EMSA analysis showed a robust and persistent activation of NFκB at least up to 72h in IR exposed cells. Consistently, IR induced a sustained transactivation (QPCR) and intercellular (ELISA) TNFα in these cells. Forced inhibition of NFκB (SN50, RelA siRNA) or TNFα (TNFR1-Ab) completely and persistently inhibited IR-induced NFκB and/or TNFα demonstrating the IR-induced initiation of NFκB→TNFα→NFκB feed back mechanism (PFC). Consistently, IR simulation experiments with NFκB (SNP, p50/p65 transfection) or TNFα (rH-TNFα) over expression, persistently activated NFκB and/or TNFα exhibiting the occurrence of PFC. Furthermore, IR profoundly induced both mRNA (QPCR) and cellular localization (immunoblotting) of IAP1, IAP2 and Survivin. NFκB knock-out experiments portrait a NFκB dependent activation of IAP1, IAP2 and Survivin in these cells. Conversely, GEN treatment completely and persistently inhibited IR-induced NFκB and, both TNFα transactivation and intercellular levels. Moreover, NFκB and/or TNFα over expression studies with GEN demonstrate the disruption of PFC. In addition, GEN markedly, inhibited IR-induced NFκB dependent IAP1, IAP2 and Survivin and greatly conferred IR-induced inhibition of cell survival. Taken together these results suggests that the surviving neuroblastoma cells may result in the development of survival advantage mediated by persistent activation of NFκB through NFκB→TNFα→NFκB PFC. More importantly, disrupting IR-initiated PFC with GEN may significantly inhibit NFκB dependent survival advantage and, may serve as a potential deliverable in mitigating neuroblastoma relapse and progression after radiotherapy.

Funding Support: ACS- IRG-05-066-01; Presbyterian Health Foundation

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 1402.
Abstract 1407: Mechanistic regulation of NFκB dependent radioprotection in human neuroblastoma
Authors: Aravindan Natarajan , Madhusoodhanan Rakhesh , Veeraraghavan Jamunarani , Herman Terence S. , Natarajan Mohan
Published: February 2011

Induced radio-resistance in cancer cells surviving after radiotherapy (RT) could be associated with increased radioprotection limiting the benefit of RT. Additionally, induced radioprotection may potentiate tumor re-growth at treatment site. Recently, we demonstrated that radiation (IR) induced NFκB in neuroblastoma cells and forced inhibition of NFκB enhanced IR-induced cell death. Accordingly, we investigated the downstream regulation involved in IR-induced NFκB-mediated radioprotection. Human SK-N-MC cells exposed to either low-dose IR (LDIR, 10, 50 and 100cGy), high dose IR (HDIR, 4Gy) or exposed to LDIR and challenged with HDIR after 24h were examined after 15min through 72h. EMSA analysis showed a marked and persistent activation of NFκB both in LDIR and HDIR exposed cells. Interestingly, cells primed with LDIR showed a robust NFκB activation when challenged with HDIR, as opposed to HDIR alone group. Consistently, we observed a significant suppression in HDIR induced DNA fragmentation (Tdt nick end labeling), apoptosis (Annexin V-FITC, caspase activity) and cytotoxicity (MTT) in cells primed with LDIR. Furthermore, clonogenic analysis revealed a profound attenuation of HDIR inhibited clonal expansion with preceding LDIR exposure. NFκB knockout (RelA siRNA) and over expression (p50, p65 transfection) studies demonstrate the influence of LDIR-activated NFκB in the regulation of HDIR induced DNA fragmentation and apoptosis. More importantly, LDIR significantly induced both transcriptional (QPCR) and cellular localization (immunoblotting) levels of radio-responsive TNFα, IL-1α, cMYC, MnSOD (SOD2 activity) and completely suppressed p53 in these cells. Co-culture experiments clearly portraits LDIR-influenced radioprotection and activation of radioresponsive molecules. Individual gene knockout (siRNA approach) studies exhibits that LDIR-modulated TNFα, IL-1α, cMYC, MnSOD and p53 mediates induced radioprotection. Furthermore, NFκB inhibition studies (ΔIκBα) demonstrated that TNFα, IL-1α, cMYC, MnSOD and p53 are selectively regulated by LDIR-induced NFκB. Collectively, these data strongly suggests that cells that survive a course of RT induce NFκB dependent radio-responsive TNFα, IL-1α, cMYC and MnSOD mediated radioprotection. Selectively targeting IR-induced NFκB could further potentiate the use of RT in neuroblastoma cell killing and mitigate tumor regrowth at treatment site.

Funding Support: ACS- IRG-05-066-01; Presbyterian Health Foundation

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 1407.
Abstract 1408: Nicotine decreases the therapeutic efficacy of radiotherapy and chemoradiotherapy in vivo
Authors: Warren Graham W. , Randall Marcus , McGarry Ronald , Kudrimoti Mahesh , Rangnekar Vivek
Published: February 2011

Background: Continued tobacco use during cancer treatment has been associated with poor outcome. Nicotine replacement is currently used as a standard of care for smoking cessation in cancer patients; however, prior data demonstrates that nicotine can promote tumor growth and decrease the effectiveness of cancer treatment in vitro.

Methods: Athymic nude mice with human H460 lung cancer cell xenografts were stratified into three Groups beginning when tumors reached 5 mm in maximal dimension: control (CON), short term nicotine (STN, 60 ug subcutaneously every other day x 6 days), or long term nicotine (LTN, 60 ug SC every other day until tumor endpoint). Within each Group, mice were further stratified into three Treatments consisting of saline (SAL), radiotherapy (RT, 3 Gy daily x 5 days), or chemoradiotherapy (CRT, RT + concurrent cisplatin intraperitoneally 3 mg/kg daily x 5 days). Tumor volumes were measured and compared between Treatments and Groups (n=10 per Treatment within each Group). This protocol was approved by the Institutional Animal Care and Use Committee at the University of Kentucky.

Results: In CON animals, RT (199 uL at day 30) or CRT (100 uL at day 30) significantly prevented tumor regrowth as compared with control SAL animals (864 uL at day 10 requiring euthanasia as per protocol). As expected, CRT was more effective than RT (p<0.05). Nicotine administration alone (STN or LTN) had no effect on tumor growth rate as compared with CON. In contrast, administration of LTN significantly increased tumor regrowth in RT animals (356 uL at day 30, p<0.05) and CRT treated animals (170 uL ad day 30, p<0.05). To eliminate the effects of nicotine on proliferation following completion of RT or CRT, animals were treated with STN. Administration of STN also significantly increased tumor regrowth in RT animals (328 uL at day 30, p<0.05) and CRT animals (176 uL at day 30, p<0.05) with virtually identical regrowth curves as demonstrated for LTN animals.

Conclusions: Results demonstrate that nicotine significantly reduces the efficacy of RT and CRT in vivo. Moreover, data suggest that nicotine use during treatment is the primary determinant of decreased therapeutic response. These results may significantly alter current recommendations for smoking cessation in cancer treatment populations.

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 1408.
Abstract 1410: Bmi-1 enhances the radioresistance of cells by suppressing the expression of NADPH oxidase genes
Authors: Dong Qinghua , Kim Roy , Chen Wei , Oh Ju-Eun , Shin Ki-Hyuk , McBride William , Park No-Hee , Kang Mo K.
Published: February 2011

Bmi-1 is a polycomb group protein necessary for cellular proliferation and maintenance of stem cell phenotype. The current study was undertaken to determine the radioprotective effects of Bmi-1 in human epithelial cells. Primary normal human keratinocytes (NHK) from oral mucosa or epidermis were infected with retroviral vectors expressing Bmi-1. NHK infected with empty virus (NHK/B0) rapidly underwent premature senescence upon exposure to 5 or 10 Gy of ionizing radiation (IR). However, the cells transduced with Bmi-1 (NHK/Bmi-1) maintained cell proliferation and clonogenicity after IR. To determine the mechanism underlying the radioresistance conferred by Bmi-1, we compared the DNA damage response (DDR), production of reactive oxygen species (ROS), and DNA repair activities in both cell types. NHK/B0 and NHK/Bmi-1 cells demonstrated rapid induction of DDR after 5 Gy irradiation. ROS production was increased by irradiation, but Bmi-1 transduction suppressed the ROS production. Irradiation strongly induced the genes encoding the enzymes involved in ROS production, mainly of NADPH oxidase subunits, but Bmi-1 completely abolished the expression of these genes. Chromatin immunoprecipitation (ChIP) revealed binding of Bmi-1 to the promoter regions of these genes in vivo, suggesting transcriptional repression by Bmi-1. In vitro DNA end joining and in vivo double strand break (DSB) repair activities were enhanced in NHK/Bmi-1 cells compared with NHK/B0. These data indicate that Bmi-1 enhances the radioresistance of NHK in part by mitigating the genotoxicity of radiation. This study was supported in part by the grants, UCLA/CBPR (U19) from NIAID and R01DE18295/K02DE18959 from NIDCR/NIH.

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 1410.
Abstract 142: A human DNA methylation analysis microarray
Authors: Ruvolo Michael , Wong Alexander , Ashutosh A. , Giles Shane , Yakhini Zohar , Roberts Douglas
Published: February 2011

CpG islands are stretches of high GC content DNA containing multiple CpG dinucleotides. When CpG dinucleotides within these islands are methylated, especially in promoter regions, expression of the corresponding downstream genes is often repressed. Aberrant CpG island methylation is implicated in cancer. We have refined a protocol for methylated DNA immunoprecipitation (mDIP) and coupled it with microarray detection. DNA isolated by mDIP is fluorescently labeled and hybridized to an oligonucleotide microarray that specifically represents putative methylation target regions in the human genome. This microarray contains ∼237,000 oligo probes tiling ∼28,000 CpG islands along with ∼5000 recently identified regions determined to be undermethylated across multiple tissue types. As proof of concept we perform mDIP and microarray analysis of human genomic DNA samples from normal tissues. We compare our mDIP array data with bisulfite sequencing data. Performing analysis with Agilent Genomic Workbench we demonstrate the ability to distinguish probes corresponding to methylated regions from probes corresponding to unmethylated regions. We then apply the assay to tumor and normal DNA and identify differential methylation patterns.

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 142.
Abstract 1421: Inhibition of melanoma growth by activation of Notch pathway in stromal fibroblasts
Authors: Shao Hongwei , Cai Long , Li Yan , Velazquez Omaida C. , Liu Zhao-Jun
Published: February 2011

Background. Tumor microenvironment influences tumor initiation and progression. Fibroblasts are major components of tumor stroma and critically involved in regulating tumor growth and angiogenesis through secretion of soluble factors, synthesis of extracellular matrix and direct cell-cell interaction. The Notch pathway regulates a variety of cellular activities. However, it is unknown whether and how manipulation of Notch signaling in stromal fibroblasts affects melanoma growth.

Objectives. This study aimed to investigate the effects of Notch-activated stromal fibroblasts on melanoma growth and elucidate the underlying mechanism.

Methods. Enforced activation of Notch pathway was achieved by transducing fibroblasts with lentiviral vector encoding activated Notch1 (NIC). The effect of Notch1-activated stromal fibroblasts on melanoma growth was tested by in vitro co-culture and in vivo co-injection approaches. The soluble factor which produced by Notch1-activated fibroblasts was identified by PCR Array and validated by Western blot analysis. Function of the candidate factor in mediating the inhibitory effect of Notch1-activated stromal fibroblasts on melanoma growth was examined through siRNA-mediated blockade approach and tested by in vitro cell co-culture and in vivo tumor xenografting animal models.

Results. Notch1-activated fibroblasts significantly inhibited melanoma growth by inducing tumor cell apoptosis and suppressing tumor angiogenesis. The inhibitory effect of NIC-engineered fibroblasts was mediated by up-regulating WISP-1 expression. Elevated WISP-1 suppressed melanoma growth while blockade of WISP-1 liberated the inhibitory effect.

Conclusions. Activation of Notch pathway in stromal fibroblasts can suppress melanoma growth, partially through WISP-1. Our study provides a novel approach to target tumor microenvironment through modulating stromal fibroblasts by manipulation of Notch signaling, and highlights WISP-1 as a potential therapeutic target in melanoma.

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 1421.
Abstract 1426: Identification of secretory stromal gene signature of the ovarian tumor microenvironment and implications for ovarian cancer progression
Authors: Thompson Melissa S. , Albitar Lina , Ghosh Sue , Wong Kwong-Kwok , Welch William R. , Birrer Michael J. , Mok Samuel C.
Published: February 2011

Ovarian cancer the deadliest gynecologic disease and despite the significant role of the tumor-associated stroma in cancer progression, little research has been done on the specific role of the tumor-associated stromal microenvironment on ovarian cancer progression. Our objective was to identify genes that are differentially regulated in the stromal component of high-grade late-stage serous ovarian cancer and illustrate direct and specific effects of their differential expression on ovarian cancer progression. Microarray analysis performed on RNA isolated from 10 microdissected normal ovarian fibroblasts, and the epithelial and stromal component of 16 high-grade late stage serous ovarian cancers revealed more than 40 secreted proteins that are overexpressed more than 5 fold by cancer-associated fibroblasts (CAFs) exclusively. Quantitative RT-PCR validated the overexpression of several genes, including sFRP2, by the CAFs. Clinical data correlated stromal sFRP2 overexpression with poorer overall survival and chemoresistance in patients with high-grade late stage serous ovarian cancer, suggesting that sFRP2 promotes ovarian cancer progression. In vitro functional studies illustrate increased ovarian cancer cell proliferation rates in response to recombinant sFRP2 as well as CAF-conditioned medium and pathway analysis via transcription-reporter assays revealed that recombinant sFRP2 signals through the NFκB and Wnt pathways in ovarian cancer cells, both of which affect cell growth. While not affecting cell proliferation, recombinant sFRP2 increased endothelial signaling to the NFAT pathway, which affects endothelial tubal branching. These results were corroborated in vivo such that microenvironments expressing higher levels of sFRP2 exhibited significantly higher microvessel density compared with microenvironments with lower sFRP2 expression. Our results illustrate a direct and specific signaling linkage from the tumor microenvironment to tumor cells and endothelial cells that contributes to tumor progression. In this case, sFRP2 exhibited significant influence on characteristics of tumor progression (i.e. tumor proliferation, microvessel morphology) suggesting that other differentially expressed genes identified by the microarray in CAFs may also play significant roles in this process.

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 1426.
Abstract 1430: Activation of WNT pathway in endometrial cancer stromal fibroblasts
Authors: Palla John , Aprelikova Olga , Yu Xiang , John Simone , Yi Ming , Stevens Robert , Risinger John , Jazaeri Amir , Niederhuber John
Published: February 2011

The dynamic interactions between tumor cells and their corresponding microenvironment play an important role in carcinogenesis. Fibroblasts are a dominant feature within a tumor stroma and have undergone a “reprogramming” to become cancer-activated fibroblasts (CAFs). In our study we established primary cell cultures of fibroblasts from matched pairs of normal human endometrium and endometrial cancer tissues and analyzed the differential expressions of mRNA and microRNA. We found that the WNT pathway was activated in CAFs and confirmed these results via Topflash luciferase reporter assays. Wingless-type (WNT) proteins are a highly conserved family of secreted glycoproteins that have been implicated in the carcinogenesis of many cancers. We demonstrated that one of the reasons for this WNT pathway activation was the methylation-dependent silencing of the secreted frizzled-related protein 4 (SFRP4), an antagonist to the WNT signaling pathway.

An additional reason for WNT pathway activation was found in the microRNA analysis. These experiments showed downregulation of miR-148a, which is a predicted regulator of the founder member of the WNT family, WNT1. We observed that CAFs have increased WNT1 protein expression in three of the five endometrial cancer CAFs. We confirmed that miR-148a directly targets WNT1 by cloning the WNT1 3'UTR into a luciferase reporter construct and showed that co-transfection with miR-148a results in a decrease of luciferase activity. When mutations to the miR-148a binding sites were introduced into the same luciferase reporter construct, the downregulation of luciferase activity by miR-148a was prevented. We conclude that the observed activation of the WNT pathway in endometrial cancer CAFs may be regulated by the miR-148a and contribute to the progression of the endometrial cancer tumorigenesis.

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 1430.
Abstract 1432: Tnfα ablation demonstrates no suppressive effect on inflammation-related mouse colon tumorigenesis
Authors: Sakai Hiroyasu , Yamada Yasuhiro , Shimizu Masahito , Moriwaki Hisataka , Hara Akira
Published: February 2011

Colorectal cancer (CRC) is one of the most serious complications of inflammatory bowel disease. Tumor necrosis factor-α (Tnfα) is a major mediator of inflammation and there is increasing evidence that Tnfα/Tnf-receptor-1 (Tnfr1) signaling may act as an endogenous tumor promoter for colon carcinogenesis. In fact, a previous study revealed that mice lacking Tnfr1 develop significantly fewer colonic tumors in the inflammation-related CRC model. Apc Min/+;Tnfα -/- mice were treated with 2% dextran sodium sulfate (DSS) and the tumor development was compared with Apc Min/+;Tnfα +/+ control mice in order to investigate the role of Tnfα by itself in the inflammation-related CRC. Surprisingly, there were no significant differences in either the severity of colonic inflammation or the expression of DSS-induced chemokines and cytokines (Ccl2, Cxcl1, Tnfβ, Il1β, Il6, and Cox-2) that relate to the colonic inflammation and tumorigenesis between these two groups. Furthermore, the genetic ablation of Tnfα did not suppress the colon tumorigenesis in comparison to the wild-type mice. These observations suggest that redundant inflammatory responses other than the Tnfα-mediated inflammation promote tumorigenesis in the colon. These results also suggest that Tnfα alone may not be an efficient target for the prevention/ treatment of inflammation-related colon tumorigenesis.

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 1432.
Abstract 1437: Laminin-1 confers Bleomycin-resistance through poly(ADP-ribose) polymerase activation in 3D culture
Authors: Benton Gabriel , Xu Hai
Published: February 2011

The purpose of this study is to examine the role of extracellular matrix proteins in regulating Bleomycin resistance and to evaluate the potential role of poly(ADP-ribose) polymerase (PARP) in modulating drug resistance in MDA-MB-231 breast cancer cells. These phenomenons were investigated using a 3D culture model where the MDA-MB-231 cells were cultured on either collagen I or laminin-1. Cells were evaluated for viability as a dose-response to the chemotherapeutic agent, Bleomycin. Cell lysates were also evaluated for PARP expression as a consequence of the 3D culture environment. Cells were then treated with the PARP inhibitor, PJ-34, and evaluated for viability as a dose-response to Bleomycin in the 3D cultures. PARP activity was assessed using a pharmacodynamic ELISA. For the first time, this study presents evidence that the basement membrane protein, laminin-1, induces Bleomycin resistance, that laminini-1 induces PARP expression and activity, and that PARP inhibition sensitizes breast cancer cells to Bleomycin treatment. In conclusion, this data provides a mechanism for ECM-mediated Bleomycin-resistance and the potential therapeutic application for PARP inhibitors to sensitize tumors to Bleomycin treatment.

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 1437.
Abstract 1442: Prognostic value of Dicer expression in human breast cancers and association with the mesenchymal phenotype
Authors: Moyret-Lalle Caroline , Grelier Gael , Lasset Christine , Voirin Nicolas , Chabaud Sylvie , Treilleux Isabelle , Puisieux Alain
Published: February 2011

Introduction:

Dicer, a ribonuclease, is the key enzyme required for biogenesis of miRNAs and small interfering RNAs (siRNAs). It was previously shown that Dicer is essential for mammalian development and cell differentiation. Recent evidence indicates that Dicer may be involved in tumorigenesis. However, no studies have examined the clinical significance of Dicer at both RNA and protein levels in breast cancer.

Methods:

In this study, the biological and prognostic value of Dicer expression was assessed in breast cancer cell lines, breast cancer progression cellular-models, and in two independent and well-characterised set of breast carcinomas with long term follow-up using tissue microarray and quantitative reverse transcription-PCR.

Results:

We have found that Dicer protein expression is significantly associated with hormone receptors status in breast tumours. Dicer mRNA expression appeared to have an independent prognostic impact in metastatic disease. In the breast cancer cell lines, lower Dicer expression was found in cells harbouring a mesenchymal phenotype and in metastatic bone derivatives of a breast cancer cell line. These findings suggested that down-regulation of Dicer expression may be related to metastatic spread of tumours.

Conclusions:

Assessment of Dicer expression may facilitate prediction of distant metastases for patient suffering from breast cancer.

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 1442.
Abstract 1444: Benzyl isothiocyanate inhibits tumor growth and lung metastasis of 4T1 murine mammary carcinoma cells in a BALB/c mouse xenograft model
Authors: Kim Eun Ji , Hong Ji Eun , Eom Soon Ju , Kim Min Hee , Park Jung Han Yoon
Published: February 2011

Benzyl isothiocyanate (BITC) is a hydrolysis product of glucotropaeolin found in cruciferous vegetables, and has been reported to have anti-tumor properties. In our previous study, we observed that BITC inhibited growth and metastatic capacity of breast cancer cells in vitro cell culture models. The present study examined the in vivo effects of BITC administration on tumor growth and metastasis of breast cancer cells. To establish the in vivo breast cancer model, 4T1 mammary carcinoma cells (5 × 104 cells) were injected into the inguinal mammary fat pad of syngeneic female BALB/c mice. One day later, the mice were divided into 3 groups and subjected to gavage with BITC (0, 5 or 10 mg/kg body weight/day) for 4 weeks. Oral administration of BITC significantly reduced the volume and weight of solid 4T1 cell tumors in BALB/c mice. BITC administration decreased the expression of proliferating cell nuclear antigen, Bcl-2, CD31 and VEGF, but increased the levels of Bax, cleaved caspase-3, −7, −9 and cleaved PARP in the tumors. In addition, Oral administration of BITC resulted in a significant reduction in the numbers of pulmonary tumor nodules and total pulmonary metastatic volume. To understand the mechanisms by which BITC exerts antimetastatic effects, metastasis-related proteins in the sera and lungs were measured by utilizing the relevant ELISA kits and Western blot analysis, respectively. BITC treatment significantly decreased the concentrations of matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, and urokinase-type plasminogen activator (uPA) in the sera of mice injected with 4T1 cells. However, the concentrations of TIMP-2 and plasminogen activator inhibitor (PAI)-1 were increased in the sera of mice treated with BITC. Additionally, the administration of BITC reduced the levels of MMP-2, MMP-9, TIMP-1, and uPA and increased TIMP-2 and PAI-1 in the lungs of these animals. In this study, we have demonstrated that BITC profoundly suppresses the tumor growth and lung metastasis in mice bearing orthotopic xenografts of 4T1 breast cancer cells. The present results indicate that BITC has potential as an anti-cancer agent for the treatment 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 1444.
Abstract 1445: Growth inhibitory and anti-metastatic effects of the hexane/ethanol extract of Glycyrrhiza uralensis in a mouse breast cancer xenograft model
Authors: Park So Young , Kwon Sujin , Park Heesook , Lim Soon Sung , Kim Jin Kyu , Kim Jong-Sang , Lee Choonghwan , Park Jung Han Yoon
Published: February 2011

Glycyrrhiza uralensis (licorice) is one of the most frequently prescribed ingredients in Oriental medicine and licorice root extracts have previously been shown to exhibit anti-carcinogenic activities. However, these extracts harbor considerable quantities of glycyrrhizin, which is known to exert anticarcinogenic activities and to induce severe hypokalemia and hypertension. In this study, we evaluated the effects of the hexane/ethanol extract of Glycyrrhiza uralensis (HEGU), which lacks glycyrrhizin, on the metastatic characteristics of 4T1 murine mammary carcinoma cells. When 4T1 cells were cultured on a transwell-filter in an in vitro cell culture model, HEGU inhibited cell migration and adhesion in a dose-dependent manner. Gelatin zymography and Western blot analysis showed that HEGU significantly suppressed the secretion and activation of the matrix metalloproteinase (MMP)-2 and MMP-9. The secretion of tissue inhibitor of metalloproteinase (TIMP)-1 was reduced in HEGU-treated cells. HEGU reduced the protein levels of intercellular adhesion molecule and vascular cell adhesion molecule. To assess the effects of HEGU on lung metastasis in vivo, we injected 4T1 cells (5×104 cells) into the inguinal mammary fat pads of syngeneic, immunocompetent BALB/c mice. One week after 4T1 cell injection, the mice were given HEGU (5 mg/kg body weight/day) in the drinking water for 25 days. HEGU treatment inhibited the solid tumor growth and the number of pulmonary tumor nodules. Immunohistochemistry results revealed that HEGU treatment reduced the expression of CD31, vascular endothelial growth factor (VEGF), proliferating cell nuclear antigen and cyclin-dependent kinase 4 in the tumor tissues. In addition, the serum concentrations of MMP-9 and VEGF were decreased in the sera of mice treated with HEGU. In the present study, we have demonstrated in both in vivo and in vitro systems that HEGU greatly inhibits the growth and lung metastasis of 4T1 cells, which was accompanied by reduced levels of MMPs, adhesion molecules and VEGF. These data suggest that HEGU possesses chemotherapeutic efficacy against breast cancer including the growth of tumor and inhibition of metastasis.

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 1445.
Abstract 145: Interactions among DNA methyltransferase isoforms and their effects on DNA methylation
Authors: Van Emburgh Beth O. , Robertson Keith D.
Published: February 2011

Alterations in DNA methylation patterns are a hallmark of cancer development demonstrated as both global hypomethylation and gene specific hypermethylation. This results in genomic instability as well as tumor suppressor gene silencing. Methylation is catalyzed by the DNA methyltransferases (DNMTs) DNMT1, DNMT3A, and DNMT3B and is assisted by DNMT3L. In order to understand the role of the DNMTs in aberrant methylation and cancer, a better understanding of how they function and interact with one another is essential. All of the DNMTs, but especially DNMT3B, are alternatively spliced generating many isoforms of unknown function. Immunodeficiency, centromere instability, and facial anomalies syndrome (ICF), which is caused by mutations in the de novo methyltransferase DNMT3B and results in altered DNA methylation patterns, is a model disease that can be studied to better understand the function of DNMT3B. We have successfully expressed each of the DNMTs using baculovirus and E. coli expression systems along with several of their common splice variants, mutations associated with ICF syndrome, and deletion constructs of Dnmt3b. A novel system was developed for these recombinant enzymes using a plasmid containing a satellite 2 sequence as a template in order to analyze both the amount of methylation and site specific methylation with bisulfite genomic sequencing and pyrosequencing. The effects of common splice variants and mutations/deletions on protein-protein interactions are being ascertained using GST pull downs and effects on their interaction with DNA examined using electrophoretic mobility shift assays. Preliminary analyses suggest that the splice variants and mutations/deletions significantly affect DNA methylation and also alter their interaction with DNMT3L and DNA. For example, Dnmt3b2 demonstrates less DNA methylation activity than Dnmt3b1, but both are enhanced by the addition of DNMT3L. Both Dnmt3b1 and Dnmt3b2 bind DNMT3L in pull down assays, but unlike Dnmt3b1 the interaction between Dnmt3b2 and DNMT3L is lost at higher salt concentrations suggesting a weaker association. Ongoing studies will provide additional insights into how interaction between Dnmt3a and Dnmt3b splice variants influences methylation and what impact mutations or deletions can have on this. We anticipate that our results will allow for an improved understanding of the functional interactions of DNMTs which will, in turn, enhance our understanding of how and why methylation patterns go awry in cancer. (Supported by NCI grants F32CA132327 and R01CA114229)

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 145.
Abstract 1451: Lipid-based Akt inhibitors preferentially kill lung cancer cells with mesenchymal features
Authors: Zhang Chunyu , Messan Koffi S. , Hobbs Evthokia , Chiang Chun-Te , Saber Barbara , Gills Joell J. , Dennis Phillip A.
Published: February 2011

Most solid tumors are epithelial in origin. A loss of epithelial-cell markers and gain of mesenchymal-cell markers (epithelial mesenchymal transition, EMT) has been observed in patient tumor samples, particularly at the leading edge or invasive front of solid tumors such as non-small cell lung cancer (NSCLC). Pathological EMT is often associated with tumor metastasis and can confer a poor prognosis. EMT is promoted by Akt activation, which contributes to the formation, maintenance, and therapeutic resistance of cancer. In this study, we found that lipid-based Akt inhibitors (LBAI) such as phosphatidylinositol ether lipid analogues (PIAs) and alkylphospholipids (perifosine and miltefosine) preferentially kill tumor cells with mesenchymal features. NSCLC cell lines that exhibited epithelial, intermediate and mesenchymal phenotypes (H322, A549 and H157, respectively) were increasingly sensitive to the cytotoxic effects of LBAI. Prolonged treatment of A549 cells with TGFbeta induced a mesenchymal phenotype and increased sensitivity to LBAI. Because EMT can be controlled by the tumor suppressor RhoB, which we previously showed was transcriptionally activated by LBAI, we investigated the role of RhoB in these cell lines. An inverse relationship between Akt activation and RhoB expression was observed in the parental cell lines as well as A549 cells treated with TGFbeta, which correlated with LBAI cytotoxicity. Stable knockdown of RhoB in A549 cells induced features of EMT including loss of E-cadherin expression, induction of vimentin expression and Akt activation, and increased cellular migration. Stable knockdown of RhoB also increased sensitivity to LBAI. These studies show that lung cancer cells with a mesenchymal phenotype are preferentially sensitivity to LBAI, and that RhoB is a critical mediator of EMT.

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 1451.
Abstract 1455: A model to predict possible parameters to assess tumor progression with Optoacoustic Imaging
Authors: Gertsch Andreas G. , Bush Nigel L. , Birtill David CCJ , Bamber Jeff C.
Published: February 2011

Optoacoustic (OA) imaging is a novel technique which allows optical absorption contrast to be visualized noninvasive using laser induced thermoelastically generated ultrasound. In tumors the highest optical absorption contrast is due to the blood/vascularization. Using optoacoustic biomarkers (such as gold nanoparticle-antibody conjugates) the signal of the vascularization could be enhanced or also other specific regions could be targeted. To assess tumor progression the size of the microvessels and the distance between them can be useful information. We found two different methods to quantify these two parameters using OA imaging. OA texture analysis and the analysis of the contrast-to-noise ratio in the reconstructed OA image and the acoustic frequency spectrum analysis in the raw signal. We present a model to predict the potential of using OA texture analysis combined with acoustic frequency spectrum analysis of the OA signal to assess the progression of tumors. The model is based on the simulation of OA signals using a time domain acoustic propagation method and a Fourier reconstruction algorithm, which has been tested with basic phantom studies. The properties of the receive part, the ultrasound (US) probe, such as the element size, center frequency or bandwidth can freely be adapted. This makes it possible to use this model with any OA system using an US system as the receiver. We show that it is possible to assess the size of optoacoustic absobers, such as the size of the microvasculature in tumors, and partly the distance between them using OA imaging. We also show the influence of a limited bandwidth of the US transducer on the outcome and therefore which transducers should be used for which application. The model has also been tested on different tumors in mice.

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 1455.
Abstract 1460: Piceatannol suppresses the migration and invasion of DU145 human prostate cancer cells
Authors: Kwon Gyoo Taik , Kim Jin-Kyung , Park Jung Han Yoon
Published: February 2011

Piceatannol (trans-3,4,3′,5′-tetrahydroxystilbene) is a polyphenol found in grapes, red wine, Rheum undulatum and seeds of Euphorbia lagascae. The purpose of the present study was to investigate the effects of piceatannol on the migration and invasion characteristics of DU145 prostate cancer cells. DU145 cells were cultured in the presence of 0 − 10 μmol/L piceatannol with or without 10 μg/L epidermal growth factor (EGF). Piceatannol inhibited the basal and EGF-induced cell migration and invasion of DU145 cells. Gelatin zymography and Western blot analysis, Fibrin zymography and real time RT-PCR analysis were conducted using conditioned media and cell extracts. Piceatannol reduced the secretion and mRNA levels of matrix metalloproteinase (MMP)-9, urokinase-type plasminogen activator (uPA), and vascular endothelial growth factor (VEGF). Piceatannol decreased the protein levels of tissue inhibitor of metalloproteinase (TIMP)-1 but increased TIMP-2 levels in a concentration-dependent manner. Additionally, piceatannol inhibited the phosphorylation of signal transducer and activator of transcription (STAT)3. Furthermore, piceatannol decreased both basal and EGF-induced secretion of IL-6. IL-6 treatment increased the secretion of uPA and VEGF, the phosphorylation of STAT3, and migration of DU145 cells and these increase were suppressed by piceatannol. An IL-6 nutralizing antibody inhibited the EGF-induced phosphorylation of STAT3 and increase in cell migration and invasion of DU145 cells, which may be mediated via the inhibition of MMP-9 and uPA activities and secretion of VEGF. The inhibition of IL-6/STAT3 activation may be one of the mechanisms by which piceatannol regulates the expression of proteins involved in the rehulation of DU145 cell migration and invasion.

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 1460.