bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 421: Epidermal growth factor-like repeats of tenascin C alter melanoma cell migration both directly and through alteration of the ECM
Authors: Grahovac Jelena , Wells Alan
Published: July 2012

In melanoma, the most aggressive type of skin cancer, invasion through the extracellular matrix (ECM) is a harbinger of dissemination and mortality. Highly upregulated in both primary invasive and metastatic melanoma is tenascin C (TNC), a hexameric ECM protein with a multidomain structure composed of the globular N-terminal domain, 14.5 epidermal growth factor (EGF)-like repeats, fibronectin-III like repeats and the C-terminal globular fibrinogen-like domain. Our group previously showed that the EGF-like repeats of TNC are able to bind the EGF receptor (EGFR) with μM affinity and preferentially activate the motogenic signaling cascades. Both normal melanocytes and melanoma cells migrate faster on surfaces coated with TNC. Therefore, we hypothesize that the increased levels of TNC in melanomas promote tumor cell migration and invasion heralding dissemination through enhanced EGFR signaling. We expressed EGF-like repeats of TNC (TNC-EGFL) in melanoma cell lines already expressing endogenous TNC and observed change in the cell morphology, and more importantly a prominent anti-adhesive phenotype. TNC-EGFL expressing cells attached with a four-hour lag compared to parental cell lines and detached to a greater extent in inverted centrifugation adhesion assays. This was not due to decreased viability of TNC-EGFL expressing cells as determined by dye exclusion assay. As this phenotype could not be reverted by adding anti-EGFR antibody, we speculate that EGFR signaling might be intracellular. In two-dimensional migration assays, TNC-EGFL expressing cells closed a gap more slowly, possibly due to inability to properly attach during migration, emphasizing the need of concerted action of different TNC domains in regulating migration. On the other hand, quantitative PCR array analysis of a panel of ECM and adhesion molecules revealed changes in matrix metalloproteinase (MMP) expression, specifically MMP-2, MMP-9 and MMP-14, and increase in TGF β1 expression, proteins associated with melanoma invasiveness and vasculogenic mimicry. These results imply that TNC-EGFL repeats are involved in melanoma invasion both by directly influencing cell migration and indirectly by altering the tumor microenvironment and may have implications for development of anti tumor therapies directed at the extracellular matrix.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 421. doi:10.1158/1538-7445.AM2011-421
Abstract 4212: Prevention of estrogen-induced breast cancer by antioxidants: Role of N-quinone oxidoreductase 1 (NQO1)
Authors: Bhat Hari K. , Singh Bhupendra
Published: July 2012

The importance of estrogens in the etiology of breast cancer is widely recognized. However, the exact mechanisms underlying the initiation and progression of estrogen-related cancers are not clear. Literature evidence and our studies strongly support the role of estrogen metabolism-mediated oxidative stress in estrogen-induced breast carcinogenesis. The objective of the current study was to characterize the role of NQO1 in the prevention of estrogen-induced DNA damage and mammary tumorigenesis by antioxidants vitamin C or butylated hydroxyanisole (BHA). NQO1 converts 17β-estradiol (E2)-quinones back to E2-catechols, thus making E2-quinones unavailable for oxidant damage. Female ACI rats were treated with E2 (3 mg); vitamin C (1% in drinking water); E2 + vitamin C; BHA (0.7% in diet); and E2 + BHA for up to 8 months. The female ACI rat is an established animal model to study the mechanisms of E2-induced breast cancer. No tumors were detected in the sham control, vitamin C and BHA treatment groups whereas in the E2 + vitamin C, E2 + BHA, and E2 treatment groups, the breast tumor incidences were 29, 24 and 82% respectively. mRNA and protein expression of NQO1 was analyzed in breast and breast tumor tissues of rats treated with E2 and antioxidants vitamin C or BHA. NQO1 was suppressed in E2-exposed mammary tissue after treatment of rats with E2 for 8 months and in mammary tumors. This suppression was overcome by co-treatment of rats with E2 and vitamin C or BHA. NQO1 enzyme activity was unchanged in mammary tissue of rats from all the treatment groups. However, NQO1 enzyme activity was decreased in E2-induced mammary tumors. Catechol-O-methyltransferase (COMT) activity was unchanged in the mammary tissue of all the groups except in the E2-treated group. Vitamin C or BHA co-treatment significantly decreased E2-mediated increase in 8-hydroxydeoxyguanosine (8-OHdG, an oxidative DNA damage marker) levels in mammary tissue. To investigate the relationship between NQO1 and 8-OHdG damage, human breast epithelial cell line MCF10A was treated with E2, vitamin C, BHA, dicumarol (NQO1 inhibitor), E2 + vitamin C, and E2 + BHA. E2 and dicumarol significantly increased 8-OHdG levels in MCF-10A cells whereas co-treatment with E2 and antioxidants reverted them back to the normal levels. Our studies suggest a protective role of NQO1 in E2-induced DNA damage and breast carcinogenesis. NQO1 may thus have a unique potential in the development of therapeutic strategies for the prevention of estrogen-induced neoplasia.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4212. doi:10.1158/1538-7445.AM2011-4212
Abstract 4215: Apoptosis induction in breast cancer cell lines by the dietary flavonoid fisetin
Authors: Smith Matthew L. , Giacomantonio Carman , Hoskin David
Published: July 2012

Canadian women have a lifetime probability of diagnosis of breast cancer of approximately 1 in 9. Although the current management of breast cancer is effective, significant morbidity and mortality are associated with the disease and its treatments. Fisetin, a phytochemical present in many fruits and vegetables, has demonstrated anticancer activity for both prostate and colon cancer. This study explores fisetin as a possible novel therapeutic modality for breast cancer. Breast cancer cell lines (MDA-MB-468, MDA-MB-231, MCF-7, T47-D, SKBR-3; mitozantrone-resistant (MITX) and paclitaxel-resistant (Tx400) cell lines) were exposed to fisetin and cell survival was assessed by MTT, crystal violet, acid phosphatase, and colony-forming assays. Normal cells (human mammary epithelial cells, fibroblasts, human umbilical vein endothelial cells) were used as negative controls. The mechanism of action of fisetin was explored using cell cycle analysis and assays for apoptosis/necrosis, including Annexin V-propidium iodide staining, DNA fragmentation measured by JAM assay, and LDH-release assay. Apoptosis induction pathways were studied using Western blotting, as well as caspase inhibitors and cell viability assays. Flow cytometry was used to assess mitochondrial membrane stability (DiOC6 staining) and reactive oxygen species (ROS) production (dihydroethidium staining). Fisetin exhibited a dose- and time-dependent cytotoxic effect on breast cancer cell lines (e.g., 100 µM fisetin decreased MDA-MB-468 cell viability by 70% at 72h in both crystal violet and acid phosphatase assays). In contrast, the viability of normal cells was not substantially affected by concentrations of fisetin that killed breast cancer cells. Fisetin-treated breast cancer cells showed cell cycle arrest (MDA-MB-468 cells arrested at G2/M phase; MDA-MB-231 cells arrested in S-phase) and death by apoptosis (e.g., MDA-MB-468 cells showed up to 50% apoptosis and 8% late apoptosis/necrosis by Annexin V-staining; cell cycle analysis and LDH-release assays supported these results). Fisetin-induced apoptosis was associated with mitochondrial membrane permeabilization but did not involve caspase activation since Western blotting showed that caspase-3 was not cleaved in fisetin-treated breast cancer cells and cell viability was not preserved in the presence of a pan-caspase inhibitor. In addition, fisetin did not cause ROS production in MDA-MB-468 or 231 cells, indicating that ROS do not contribute to the cytotoxic effect of fisetin. Together, these findings suggest that fisetin may be useful in the treatment of breast cancer. Ongoing studies are using Zebra fish as a model to explore the in vivo anticancer activity of fisetin.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4215. doi:10.1158/1538-7445.AM2011-4215
Abstract 4228: Ganoderma lucidum (Reishi) reduces inflammatory breast cancer progression via protein synthesis inhibition
Authors: Rosario-Acevedo Raysa , Cubano Luis A. , Dharmawardhane Suranganie F. , Martinez-Montemayor Michelle M.
Published: July 2012

The anti-cancer effects of the medicinal mushroom Ganoderma lucidum (Reishi) were tested as a potential therapeutic for Inflammatory Breast Cancer (IBC). IBC is a rare, lethal and aggressive form of locally advanced breast cancer that manifests itself without a typical tumor mass. Studies suggest that the mammalian target of rapamycin (mTOR) pathway is a key regulator of cell growth via the regulation of protein synthesis. The mTOR effectors for protein synthesis are eukaryotic initiation factor 4E-binding protein 1 (4EBP-1) and the ribosomal protein S6 kinase (p70S6K). The 4EBP-eIF4E complex exerts control over cap-dependent translation, while p70S6K stimulates eIF4F translation of specific mRNAs with highly structured 5′UTRs, promoting cell growth, and tumor progression. In IBC the eukaryotic initiation factor, eIF4GI is overexpressed, which reprograms protein synthesis for cap-independent translation via increased initiation of internal ribosome entry site (IRES)-dependent translation. eIF4GI increased mRNA translation is partly responsible for the unique IBC pathological properties: overexpression of E-cadherin, strong homotypic IBC cell interaction, and formation of tumor emboli to promote IBC cell invasion. Using the patient derived IBC cell line, SUM 149, we previously demonstrated that Reishi extract selectively inhibits IBC cell growth and invasion by downregulating the expression of genes involved in invasion, survival and proliferation, and the protein expression of E-cadherin. The present study demonstrates that Reishi extract reduces the expression of AKT, which signals to activate the translational machinery by mTOR. Reishi extract reduced the expression of p70s6K and eIF4G, and diminished the expression of the IRES dependent mRNA containing proteins: c-Myc, p120 catenin, vascular endothelial growth factor (VEGF), BCL-2 and BCL-XL. Furthermore, Reishi extract reduced the expression of eIF4E and the phosphorylation of its inhibitor, 4EBP-1. Our results provide evidence that Reishi suppresses protein synthesis potentially by both cap-dependent and cap independent mechanisms. Our findings suggest that Reishi is a potential natural therapeutic that can be used in combination with traditional therapy to treat this intractable and deadly disease.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4228. doi:10.1158/1538-7445.AM2011-4228
Abstract 4229: Dichamanetin, a C-benzylated flavonoid from Piper sarmentosum inhibits cell growth and induces G1 cell cycle arrest in cancer cells through mitochondrial-mediated apoptosis
Authors: Matthew Susan , Pan Li , Shen Qi , Kinghorn A. Douglas , Swanson Steven M. , Carcache de Blanco Esperanza J.
Published: July 2012

Dichamanetin (C29H24O6) is a rare C-benzylated flavanoid isolated as a major metabolite from Piper sarmentosum Roxb. (Piperaceae). Dichamanetin significantly decreased the cell viability of various types of cancer cells in a dose- and time-dependent manner, characterized by G1 arrest of the cell cycle. In the present study, we investigated the molecular mechanism whereby dichamanetin exerts its cytotoxic effect on human cancer cells in vitro. We examined the involvement of ROS-signaling components (ROS levels, NF-kB transcription factor, mitochondrial membrane potential, DNA damage, and proteasome inhibition) and demonstrated that the antiproliferative effect of cancer cells is partially mediated by induction of oxidative stress. Dichamanetin treatment did not significantly inhibited proteasome, but inhibited moderately PARP-1 enzyme activity. Additionally, FACS analysis with JC-1 fluorescent dye established significant deviation of mitochondrial membrane potential by dichamanetin in treated cells. The present data therefore supports dichamanetin as an active anti-proliferative metabolite that acts in part through mitochondrial-mediated apoptosis.

Acknowledgment

This research was supported by Program Project Grant P01-CA125066 funded by the National Cancer Institute, NIH.

We also wish to acknowledge the plant taxonomists who collected the plant material used in this investigation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4229. doi:10.1158/1538-7445.AM2011-4229
Abstract 4233: Protolimonoids potently suppress mitochondrial respiration and disrupt protein translation in breast tumor cells
Authors: Zhou Yu-Dong , Li Jun , Mahdi Fakhri , Du Lin , Datta Sandipan , Nagle Dale G.
Published: July 2012

Hypoxia (decreased oxygen tension) is a common feature of solid tumors and represents an obstacle for cancer treatment. The transcription factor hypoxia-inducible factor-1 (HIF-1) has emerged as an important molecular target for antitumor hypoxia drug discovery. A natural product chemistry-based approach was utilized to identify small-molecule HIF-1 inhibitors. Over 20,000 extracts of plants and marine organisms were evaluated for HIF-1 inhibitory activities. An active extract of the sacred medicinal Bael Tree (Aegle marmelos) trunk bark was subjected to bioassay-guided isolation and de-replication-based structure elucidation yielded two known protolimonoids skimmiarepin A (1) and C (2). Compounds 1 and 2 inhibited hypoxia-induced HIF-1 activation in a human breast tumor T47D cell-based reporter assay (IC50 values 0.063 and 0.068 μM, respectively). The hypoxic induction of HIF-1 target genes GLUT-1 and VEGF were also inhibited by 1 and 2. Mechanistic investigation revealed that 1 and 2 suppressed HIF-1 activation by blocking the accumulation of nuclear HIF-1α protein under hypoxic conditions. To test the hypothesis that these protolimonoids may interfere with hypoxic signaling by disrupting mitochondrial function, the effects of 1 and 2 on cellular respiration were examined. Both compounds inhibited T47D cell respiration at the range of concentrations that inhibited hypoxic HIF-1 activation. Compound 1 suppressed mitochondrial electron transport chain at complex I (NADH dehydrogenase). Under experimental conditions, neither 1 nor rotenone (positive control for complex I inhibitor) decreased cellular ATP content following a two-day exposure. However, rotenone and 1 suppressed cellular signaling pathways that control protein translation. While it is commonly believed that the antitumor activity of mitochondrial inhibitors is a consequence of their ability to inhibit cellular ATP production, the disruption of protein translation appears to constitute an important mechanism by which mitochondrial inhibitors obstruct tumor cell proliferation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4233. doi:10.1158/1538-7445.AM2011-4233
Abstract 4235: Antiproliferative effects of cucurbitacin B in breast cancer cells: Down-regulate c-Myc/hTERT/telomerase pathway and obstruct the cell cycle
Authors: Duangmano Suwit , Dakeng Sumana , Jiratchariyakul Weena , Suksamrarn Apichart , Smith Duncan R. , Patmasiriwat Pimpicha
Published: July 2012

Abstract: Naturally occurring cucurbitacins have been shown to have anticancer, antimicrobial and anti-inflammatory activities. In this study, we determined the effects of cucurbitacin B extracted from Thai herb Trichosanthes cucumerina L. on the regulation of telomerase in three human breast cancer cell lines (T47D, SKBR-3, and MCF-7) and a mammary epithelium cell line (HBL-100). Cell viability after treatment with cucurbitacin B which is an active ingredient of this herb, was assessed by MTT assay and cell cycle analysis by flow cytometry. Telomeric Repeat Amplification Protocol (TRAP) assays and RT-PCR (qualitative and realtime) were performed to investigate activity of telomerase as well as expression of human telomerase reverse transcriptase (hTERT) and c-Myc. The c-Myc protein level was also determined in SKBR-3 and HBL-100. Our results show that the cucurbitacin B inhibits growth and telomerase activity in the three breast cancer cell lines and an obvious inhibitory effect was seen in the estrogen receptor (ER)-negative breast cancer cell SKBR-3 rather than ER-positive MCF-7 and T47D cells. The expressions of hTERT and c-Myc were also inhibited by cucurbitacin B, In addition, the reduction of c-Myc protein after the treatment was clearly observed in SKBR-3 cells even at the ten times lower concentration of cucurbitacin B compared to the concentration used for the HBL-100. DNA flow cytometric analysis indicated that treatment with cucurbitacin B resulted in G2/M arrest. These results imply that cucurbitacin B exerts anticancer effect by inhibiting telomerase via down regulating both the hTERT and c-Myc expression and arrest of the cell cycle at G2/M phase in breast cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4235. doi:10.1158/1538-7445.AM2011-4235
Abstract 4261: Anti-angiogenic effects of zoledronic acid on osteotropic breast cancer cells
Authors: Contreras Cynthia , Hamud Walid , Dhakal Bishal , Khanal Bijay , Bush Jason
Published: July 2012

Emerging data suggest the bisphosphonate, zoledronic acid (ZOL), exerts both indirect and direct anti-tumoral effects by decreasing tumor cell proliferation, increasing apoptosis, and inhibiting angiogenesis. Recent data indicate that anti-angiogenic factors exert cellular effects via suppression of mitochondrial oxidative phosphorylation/respiration and elevation of intracellular ROS levels. This project intended to define proteins involved in response to ZOL-treatment of an osteotropic breast cancer cell line, MDA-231BO. Results demonstrate that MDA-231BO cells are more sensitive to ZOL cytotoxicity and salutary effects are both media- and calcium-dependent. To investigate pro-apoptotic mechanisms of ZOL, total RNA, whole cell protein lysates, or mitochondrial-enriched fractions were isolated from MDA-231BO cells and using a combination of RT-PCR, 1D/2D-PAGE separation and MALDI-MS/MS, we identified several angiogenesis inhibitors that were upregulated and pro-angiogenic factors that were downregulated after ZOL treatment. Functional studies demonstrate the improved efficacy of ZOL on MDA-231BO compared to MDA-MB-231 controls. Taken together, these results further support a model that ZOL tips the ‘angiogenic switch’ in favor of anti-angiogenic factors in cancer cells with a propensity for bone metastases. Partial research support came from NIH 5P20MD002732

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4261. doi:10.1158/1538-7445.AM2011-4261
Abstract 4266: Acquired resistance to sorafenib yields CXCL12 (SDF1α) over-expression and increases invasion in hepatocarcinoma cells
Authors: Riveiro Maria E. , Serova Maria , Huet Guillemette , Dumont Patrick , Dokmak Safi , Albert Sébastien , Bieche Ivan , Raymond Eric , Faivre Sandrine
Published: July 2012

Background: Sorafenib has a well known efficacy in patients with advanced hepatocellular carcinoma (HCC). Sorafenib displays antiangiogenic effects by targeting receptors for VEGF (VEGFR2 and VEGFR3) and PDGF (PDGFRβ) and blocks cancer cell proliferation by targeting RAF/MEK/ERK signalling. However, disease-stabilizing effects are eventually followed by emergence of resistance in patients. The aim of the present work was to describe mechanisms associated with acquired resistance to sorafenib.

Materials and Methods: Cell proliferation and clonogenic survival were evaluated in sorafenib-sensitive and -resistant HCC models. Invasiveness of cells was determined by Matrigel invasion assay. qRT-PCR and western blot assays were used to assess a panel of genes and proteins. In vivo sorafenib efficacy was determined in SCID mice bearing SK-HEP1 xenografts. The drug was administered orally, once daily at dose levels of 10 and 30 mg/kg until sorafenib-resistance appearance, starting when tumors were detectable (100-300mm3).

Results: The SK-sora cell line was established from the parental SK-HEP1 cell line using a stepwise exposure to increasing sorafenib concentrations for more than 6 months. Exposure to 48-hour sorafenib led to IC50s of 8.3 and 15.9 µM in SK-HEP1 and SK-sora cells, respectively. Clonogenic assay also indicated a significant sorafenib resistance in SK-sora cells. Sorafenib-resistant cells did not display cross-resistance to sunitinib, another multitarget inhibitor. In addition, 30 days sorafenib withdrawal did not restore the sensitive to the drug in Sk-sora cells. Protracted exposure to sorafenib led to a 3-fold increase mRNA expression of VEGFA, VEGFD, erbb4, IGFR1, CXCL12 (SDF-1α) and MIF in SK-sora respect to parental SK-HEP1 cells. In addition we observed a basal up regulation of MAPK and AKT survival signalling pathways as measured by p-ERK1/2, p-AKT and p-S6rp levels in SK-sora cells. Matrigel assay revealed a 3 fold (p<0.05) increase in the number of invasive SK-sora cells respect to SK-HEP1 cells. Current in vivo studies point out that sorafenib (30 mg/kg/day) significantly suppressed SK-HEP1 xenograft tumor growth (34.6%; p<0.05) after 25 days of treatment. Mechanisms associated with resistance to sorafenib in mice will be explored.

Conclusions: Our data show that acquired resistance to sorafenib is associated with the activation of the AKT and MAPKs pathways together with an increased invasion in HCC cells. The role of CXCR4/CXCL12 axis in this model will be explored.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4266. doi:10.1158/1538-7445.AM2011-4266
Abstract 4269: Human monoclonal anti-angiopoietin-2 antibody, MEDI3617, inhibits angiogenesis in preclinical studies
Authors: Molnar Nikolett , Siemann Dietmar W.
Published: July 2012

Angiogenesis is two-step process that is critical in tumor angiogenesis. First, endothleial-endothelial and endothelial-smooth muscle cell interactions must be broken. Then, endothelial cells must be activated to proliferate, migrate, and form tubes. Presence of Angiopoietin-2 (Ang-2) leads to vessel destabilization while pro-angiogenic factors like Vascular Endothelial Growth Factor (VEGF) are key growth factors that activate new vessel formation. Both are upregulated in the tumor microenvironment. To date most anti-angiogenic therapies have focused on inhibiting the second step in angiogenesis, or activation of the endothelium, and anti-VEGF therapies have shown some success especially in combination with conventional cancer therapies. However, resistance to such therapies has emerged due to upregulation of other pro-angiogenic factors in the absence of VEGF. The present studies examine the impact of MEDI3617, a monoclonal antibody targeting Ang-2, on tumor cell induced angiogenesis by inhibiting the first step, or endothelial-endothelial and endothelial-smooth muscle cell interactions, in angiogenesis. An intradermal assay was used to evaluate the growth of vessels induced by the tumor. Nude mice injected intradermally with colorectal cancer cells, HT29, were treated with a range of MEDI3617 doses (2, 10, 20 mg/kg) and the effect on the number of vessel formation was determined. The results showed that at 2 mg/kg dose of MEDI3617 led to a 42% reduction in the number of vessels induced and 10 and 20 mg/kg induced even greater reduction in the number of vessels (48 and 61% respectively). Current studies are evaluating the mechanistic interaction of endothelial- endothelial cell and endothelial smooth-muscle cell interactions using a co-culture spheroid model. A core of smooth muscle cells are surrounded by a layer of endothelial cells mimicking the interaction of these cells in the vasculature. The effect of Ang-2 on destabilizing this co-culture spheroid and the ability of MEDI3671 on inhibiting this destabilization are being evaluated. Preliminary studies indicate the ability of MEDI3617 to inhibit sphere destabilization in the presence of Ang-2.

Human monoclonal anti-Ang-2 antibody, MEDI3617, was both developed and this study supported by MedImmune, LLC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4269. doi:10.1158/1538-7445.AM2011-4269
Abstract 4271: Combination of VEGF Trap (Aflibercept) with docetaxel, but not with gemcitabine, is efficacious in tumors resistant to anti-VEGF therapy
Authors: Abrahams Cristina L. , Li Baosheng , Parveen Asma , Thurston Gavin
Published: July 2012

Increased anti-tumor efficacy is often observed when VEGF blockade is combined with certain chemotherapy agents. However, the mechanism by which combination treatment with certain agents, but not others, results in enhanced anti-tumor effects is poorly understood. In this study, we compared the anti-tumor effects of VEGF Trap in combination with either docetaxel or gemcitabine on HT1080, a human fibrosarcoma tumor line that is resistant to anti-VEGF treatment. Immunodeficient SCID mice bearing subcutaneous HT1080 tumors (size ∼150 mm3) were treated with either control protein plus vehicle, VEGF Trap, chemotherapy agent (docetaxel or gemcitabine), or the combination. Following three treatments administered every 3-4 days, tumors were harvested either one day after the final dose or allowed to grow and harvested when the average size of the treatment group reached ∼500mm3. We found that combination treatment with VEGF Trap plus docetaxel was significantly more effective compared to single agents, while there was no added benefit of combining VEGF Trap with gemcitabine. Although treatment with chemotherapy agents alone and in combination with VEGF Trap both initially regressed tumor size, only the combination with docetaxel was effective at delaying long-term tumor re-growth. Immunohistochemical analysis of tumors showed that both combination regimens produced a dramatic decrease in the number of proliferating tumor cells. However, only VEGF Trap and docetaxel combination treatment resulted in pruned tumor vessels with less branching, whereas VEGF Trap plus gemcitabine had minimal effect on tumor vessel morphology. Furthermore, VEGF trap plus docetaxel produced an increase in TUNEL-positive cells associated with the tumor vasculature and a marked decrease in tumor pericytes. These results suggest that in tumors resistant to VEGF blockade, taxanes (docetaxel) can sensitize the vasculature to anti-VEGF treatment (aflibercept), thus resulting in enhanced effects on the tumor vessels and improved anti-tumor efficacy. Further understanding of the mechanistic basis of different combination regimens may allow improvement of current strategies to treat tumors resistant to antiangiogenic therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4271. doi:10.1158/1538-7445.AM2011-4271
Abstract 428: Positive correlation of beta1 integrin expression and prognosis in clinically localized prostate cancer
Authors: Jr Jose Pontes , Ribeiro-Filho Leopoldo Alves , dos Reis Sabrina T. , Timoszczuk Luciana , Bernardes Felipe S. , Antunes Alberto A. , Viana Nayara I. , Passerotti Carlo C. , Oliveira Luiz CN , Hagopian Ellen , Dall'Oglio Marcos F. , Leite Katia RM , Srougi Miguel
Published: July 2012

Introduction and objective: Integrins are transmembrane glycoprotein receptors that regulate cell-matrix interactions, functioning as sensors of the environment. They also act as cell adhesion molecules, being responsible for the maintenance of the epithelial phenotype. Some studies have reported correlation between alterations of integrins expression and carcinogenesis, specially β1 integrin, but their role in prostate cancer is unclear. Our aim is to study the expression of β1 integrin and evaluate its association with recurrence of prostate cancer after surgical treatment

Methods: For this case-control study, we selected 111 patients with localized tumor submitted to radical prostatectomy by the same surgeon. 60 of these patients have not presented recurrence after a median follow-up of 123 months. Recurrence was defined as a PSA level above 0.4ng/ml. Integrin expression was evaluated by immunohistochemistry in a Tissue Microarray containing two samples from each tumor. We employed a semiquantitative analysis and considered a case as positive when the expression was strong and diffusely present. We correlated expression with recurrence employing the χ2 test and p<0.05 was considered significant.

Results: Positive expression of β1 integrin was found in 79 out of 100 evaluated cases, ten cases were lost in the tissue microarray. Correlating expression with recurrence we found in the univariate analysis that negative expression of β1 integrin was statistically associated with recurrence (p=0,042) and time to recurrence after radical prostatectomy, when expression of β1 is negative, the odds of recurrence was two times higher than that observed in positive cases (p=0.026 – IC 95% [1.09; 3.83]. In multivariate analysis, including PSA and Gleason, β1 integrin remained independently associated with recurrence p=0.01.

Conclusions: In the present study we have shown that a down regulation of β1integrin expression was significantly correlated with recurrence after radical prostatectomy for localized prostate cancer, making this integrin a potential candidate as a marker of prognosis. Larger series will be evaluated in order to confirm our initial findings

Figure Kaplan Meier curve for recurrence-free survival according to β1expression in 111primaryPCa submitted to RP

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 428. doi:10.1158/1538-7445.AM2011-428
Abstract 4286: Essential Roles of Jab1 in Cell Survival, Spontaneous DNA Damage, and DNA Repair
Authors: Claret Francois
Published: July 2012

Jun activation domain-binding protein 1 (JAB1) is a multifunctional protein that participates in the control cell proliferation and the stability of multiple proteins. JAB1 overexpression has been implicated in the pathogenesis of human cancer. JAB1 regulates several key proteins and thereby produces varied effects on cell cycle progression, genome stability, and cell survival. However, the biological significance of JAB1 activity in these cellular signaling pathways is unclear. Therefore, we developed mice that were deficient in Jab1 and analyzed the null embryos and heterozygous cells. This disruption of Jab1 in mice resulted in early embryonic lethality due to accelerated apoptosis. Loss of Jab1 expression sensitized both mouse primary embryonic fibroblasts and osteosarcoma cells to gamma radiation-induced apoptosis, with an increase in spontaneous DNA damage and homologous recombination (HR) defects, both of which correlated with reduced levels of the DNA repair protein Rad51 and elevated levels of p53. Furthermore, the accumulated p53 directly binds to Rad51 promoter, inhibited its activity, and represent a major mechanism underlying the HR repair defect in Jab1-deficient cells. These results indicate that Jab1 is essential for efficient DNA repair and mechanistically link Jab1 to the maintenance of genome integrity and to cell survival.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4286. doi:10.1158/1538-7445.AM2011-4286
Abstract 4289: Using the right tools: A catalog of ovarian cancer cell lines by subtype
Authors: Anglesio Michael S. , Sheppard Karen E. , Salamanca Clara M. , Chow Christine , Pearson Rick B. , Wang Yuzhuo , Kobel Martin , Gilks Blake , Kalloger Steve E. , Huntsman David G.
Published: July 2012

Ovarian cancer cell lines provide an important tool in exploring disease phenotypes and biology. Within the spectrum of ovarian epithelial cancers at least five histologically distinguishable unique diseases exist: high-grade serous, clear cell, endometrioid, mucinous, and low-grade serous. While sharing a common site of presentation, these ovarian cancer types exhibit distinct genomic signatures, clinical characteristics and treatment responses. Thus, the critical interpretation of the results of cell based experiments performed in in-vitro and in-vivo model systems of ovarian cancer first requires characterization of the disease subtype each model represents. Our group has recently used a minimal panel of nine immunohistochemical (IHC) markers, termed “COSP” (Calculator for Ovarian carcinoma Subtype Prediction), to predict each ovarian cancer type. Application of COSP has suggested that as many as 19% of primary ovarian cancer samples may be misclassified prior to an expert review. Commonly used cell lines are rarely classified into ovarian cancer types, confounding interpretation of results and potentially delaying transition of basic research to clinically relevant application. We now apply COSP for typing commonly used ovarian cancer cell lines, as well as in-house derived xenografts, and primary culture models. The COSP immuno-predictive tool is combined with molecular and mutational data to support each cell line's subtype prediction while primary tumour types are compared to their derivative cell lines. We now present an extensive panel of accurately classified ovarian cancer cell lines to facilitate disease specific analysis of the biology of ovarian cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4289. doi:10.1158/1538-7445.AM2011-4289
Abstract 43: Using matrix factorization to discover clinically-relevant molecular signatures across cancers
Authors: Szeto Christopher W. , Zhu Jingchun , Durbin James , Benz Stephen , Vaske Charles , Stuart Joshua , Haussler David
Published: July 2012

With increasing ubiquity of genome-wide assays it is now common to molecularly subtype cancers to predict patient therapy response. However identifying high-performing, robust molecular signatures for predictions remains difficult. Presented here is work towards a novel machine-learning algorithm that discovers intuitively understood and clinically relevant stratifying molecular signatures. This classification method, as well as many competing methods (SVM, random forests, Bayes nets, etc.), were applied by predicting drug-sensitivity to hundreds of compounds tested on the NCI60 cell lines. This new drug-sensitivity prediction method competes with and in many cases outperforms leading classifiers. The prediction results, as well as the molecular signatures that they are derived from, are publicly available for web-browsing through a new extension to the UCSC Cancer Genomics Browser, hgClassifications (http://genome-cancer.soe.ucsc.edu/hgClassifications).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 43. doi:10.1158/1538-7445.AM2011-43
Abstract 4319: Effects of chemotherapeutics on organotypic corticostriatal slice cultures identified by a new panel of fluorescent and immunohistochemical markers
Authors: Jensen Stine S. , Nørregaard Annette , Kolenda Jesper , Aaberg-Jessen Charlotte , Garnier-Christensen Karina , Jensen Poul H. , Schrøder Henrik D. , Kristensen Bjarne W.
Published: July 2012

Effects of chemotherapeutics on glioma cell lines and spheroids are usually investigated without evaluating the effects of even very high concentrations of chemotherapeutics on normal brain tissue. To perform such investigations, the aim of the present study was to establish a panel of markers for detection of general cell death and more specific neuronal and glial degeneration induced by chemotherapeutics in organotypic rat corticostriatal slice cultures. Organotypic rat corticostriatal slice cultures were exposed to the alkylating agents temozolomide and nimustine, the tyrosine kinase inhibitor imatinib mesylate and the microtubule destabilizing agent vincristine. Densitometric measurements of uptake of the fluorescent dye propidium iodide were used for quantifying cellular degeneration. Moreover, paraffin sections were HE stained and immunohistochemically stained for the neuronal marker MAP2, the astroglial marker GFAP, and the oligodendrocyte marker p25α. The results showed that clinical drug concentrations were non-toxic. However, a time dependent increase in PI uptake was observed for supratherapeutic concentrations of the drugs, except for temozolomide, where no toxicity was observed at all. Corresponding immunostaining showed loss of MAP2 staining and increased expression of GFAP and p25α for cultures exposed to 1000 nM vincristine. Cultures exposed to supratherapeutic concentrations of nimustine and imatinib mesylate disintegrated, leaving no tissue for histology.

In conclusion, corticostriatal slice cultures and the established panel of markers represent an excellent tool for detecting toxicity by chemotherapeutics. Toxicity was not detected at clinical concentrations, but high concentrations with toxic effects were identified suggesting that some of the earlier identified anti-cancer effects in the literature are general cytotoxic effects and not specific anti-cancer effects.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4319. doi:10.1158/1538-7445.AM2011-4319
Abstract LB-162: Blockade of PD-L1 signaling, but not depletion of regulatory T cells, delays tumor growth in a murine pancreatic tumor model
Authors: Vohra Nasreen A. , Sarnaik Amod , Mackay Amy , Ghansah Tomar , Pilon-Thomas Shari
Published: July 2012

Pancreatic cancer is an aggressive disease with poor prognosis. Immunotherapy may be less effective in treating pancreatic tumors due to tumor-mediated suppression. Several mechanisms may contribute to immune suppression seen in mice bearing Panc02 pancreatic adenocarcinomas. We measured an increase in the percentage of CD4+CD25+foxp3+ regulatory T cells (Tregs) in the tumor and spleens of mice bearing Panc02 tumors (p<0.001 compared to non-tumor bearing mice). These Tregs were capable of suppressing antigen-specific T cell proliferation in a dose-dependent manner. Treatment of mice bearing Panc02 tumors using combination therapy with dendritic cells (DC) and anti-CD25 antibody (PC-61) did not demonstrate a delay in tumor growth or survival. As depletion of Tregs had little effect on Panc02 tumor growth, we examined another mechanism of immune suppression. We measured the expression of programmed death ligand-1 (PD-L1) on the surface of Panc02. PD-L1 plays a crucial role in inhibiting T cell responses and maintaining peripheral tolerance. PD-L1 expression has been measured on most pancreatic adenocarcinomas and may lead to down-regulation of antigen-specific T cell responses. To examine PD-L1 signaling blockade, mice bearing Panc02 tumors were treated with anti-PD-L1 antibody at 3 day intervals. After 3 weeks, mice receiving anti-PD-L1 antibody displayed smaller tumors than mice receiving control antibody (134 mm2 vs 221mm2 respectively, p<0.05). Splenocytes from PD-L1 treated mice secreted IFN-gamma in response to restimulation with Panc02 (p<0.01 compared to control treated mice). Furthermore, treatment with anti-PD-L1 antibody in Panc02-bearing athymic nude mice had no effect on tumor growth, indicating that treatment is T cell dependent. Survival benefit was measured in tumor-bearing mice when anti-PD-L1 antibody treatment was combined with DC immunizations (35% survival on day 75 compared to 0% in all control groups, p<0.05). To enhance this treatment, we examined combination therapy with DC, anti-PD-L1 and PC-61 antibodies. Depletion of Tregs did not enhance therapy with DC and anti-PD-L1 antibody. Together, these studies show that blockade of PD-L1 signaling inhibited tumor growth in mice with pancreatic cancer. Depletion of Tregs alone or in combination with PD-L1 blockade demonstrated no benefit in this model. Studies to optimize combination therapy using anti-PD-L1 antibody and DC-based vaccines are ongoing.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-162. doi:10.1158/1538-7445.AM2011-LB-162
Abstract LB-164: B lymphocytes inhibit anti-tumor response in a murine EMT6 tumor model by facilitating expansion of T regulatory cells
Authors: Zhang Yu , Tadmor Tamar , Eliav Yair , Schreiber Taylor H. , Podack Eckhard R. , Levy Robert , Shin Seung-uon , Rosenblatt Joseph D.
Published: July 2012

B lymphocytes play a central role in inhibiting the immune response against certain tumors, but the underlying mechanisms by which B cells facilitate tumor growth are still poorly understood. Murine EMT6 mammary tumors grow readily in immune competent mice (ICM) but poorly in B-cell deficient μ−/− BALB/c mice (BCDM). Both decreased T regulatory cell (Treg) expansion and impaired Treg function were observed in BCDM compared to ICM. In this study, we investigated how the presence or absence of B cells affects expansion of Tregs in response to tumor implantation. We compared tumor growth, and the number of Treg cells, T cell function, number and character of tumor infiltrating cells, immune effector molecule, chemokine and cytokine expression in tumor tissue in ICM, compared to BCDM and B cell reconstituted BCDM (BCDM+B).

Partial reconstitution of BCDM with adoptively transferred B cells restored tumor growth. Transfer of both normal and IL-10−/− B cells restored tumor growth in BCDM. Restored tumor growth correlated with an increase in CD4+FoxP3+ Treg cells in the spleen and draining lymph nodes and a decrease in interferon-γ secretion and cytotoxic T cell activity against EMT6 targets, in BCDM+B to BCDM. Tumor growth was completely inhibited in BCDM+B by depletion of Treg using PC61 antibody. Markedly increased levels of NK and CD8+ T cell infiltration into the tumor bed were seen in BCDM or BCDM+B treated with Treg depletion, compared to levels of infiltration seen in ICM or BCDM+B mice. PCR array analysis of mRNA expression in tumor tissue in BCDM, BCDM+B treated with PC61 antibody, or ICM following PC61 treatment, revealed down regulation of IL-17A, IL-17F, TGF-β and IL-23, CD73, VEGF-C, Rorγt and CCR4, when compared to either BCDM+B or BALB/c control mice. We observed similar changes in immune effector molecules/cytokines mRNA in all scenarios in which Treg levels were decreased.

In conclusion, our studies indicate that the T cell anti-tumor response is enhanced in the absence of B cells, in part due to effects on Treg cell expansion and changes in immune effector molecule and cytokine profile in the tumor micro-environment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-164. doi:10.1158/1538-7445.AM2011-LB-164
Abstract LB-174: A DNA hypermethylation module for the stem/progenitor cell signature of cancer
Authors: Easwaran Hariharan , Johnstone Sarah E. , Van Neste Leander , Ohm Joyce E. , Mosbruger Tim , Aryee Martin , Yegnasubramanian Srinivasan , Matsui William , Baylin Stephen B.
Published: July 2012

It has been firmly established that cancer gene expression partly mimics the gene expression signature in embryonic stem cells (ESC). Since most cancers arise in adult stem or progenitor cells, rather than ESC, we now compare cancer chromatin to both embryonic and adult cell renewal systems to understand the relationships between DNA hypermethylation, gene expression, and chromatin states. DNA hypermethylation at CpG island promoters of hundreds of genes, including classic tumor suppressors, is a major modulator of gene expression in human cancers. Past studies suggest ∼ 50% of these are frequently marked by polycomb complex (PcG) transcriptional repressors, but not DNA methylation, in embryonic stem cells (ESC). In ESC, PcG occupancy is predominantly in the context of “bivalent chromatin”, wherein the active transcription mark H3K4me3 and the repressive PcG mark H3K27me3 are simultaneously present. Genes so marked are in a low, but poised, transcription state important for stemness and self-renewal, characteristics shared with tumor cells. Using whole genome ChIP-seq and DNA methylation arrays, we find between 70 to 80% of genes with DNA hypermethylation in cancer have bivalent chromatin not only in ESC, but also in adult stem cells. For these genes, there appears to be an epigenetic switch in cancer wherein bivalent chromatin is replaced by DNA hypermethylation resulting in tighter repression of gene expression. Many of these DNA methylated cancer genes are constituents of the recently proposed “PRC module” of the “ESC cancer signature.” Our data suggest a “DNA methylation module” that recapitulates the “stem cell signature” and that DNA hypermethylation may be a key mechanism that confers cell-renewal and stemness to tumor cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-174. doi:10.1158/1538-7445.AM2011-LB-174