bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2565: Aryl hydrocarbon receptor agonist 5F 203 induces oxidative stress triggering DNA damage and cytoglobin up-regulation in human breast cancer cells
Authors: Rowland Leah K. , McLean Lancelot S. , Campbell Petreena , Watkins Cheri N. , Zylstra Dain , Amis Louisa H. , Senthil Maheswari , Brantley Eileen
Published: August 2015

Breakthroughs are needed in breast cancer therapy to improve clinical outcomes. Emerging evidence suggests that tumorigenesis stems, in part, from epigenetically silenced tumor suppressor genes (TSGs) and restoring TSGs may represent a viable strategy to treat breast cancer. We previously found that aryl hydrocarbon receptor (AhR) agonist 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203) exhibits potent cytotoxicity, increases reactive oxygen species (ROS), induces DNA damage and up-regulates the expression of putative tumor suppressor gene cytoglobin in breast cancer cells. In the current study, we seek to delineate the mechanism by which 5F 203 induces DNA damage and cytoglobin expression in susceptible breast cancer cells. We found that 5F 203 activated p38 mitogen activated protein kinase (p38) and c-Jun-N terminal kinase (JNK) signaling in breast cancer cells. Pretreatment with antioxidant N-acetyl-L-cysteine or AhR inhibitor α-naphthoflavone diminished 5F 203-mediated p38 or JNK activation in a cell context-dependent fashion. Pretreatment with pharmacological inhibitors of p38 or JNK suppressed 5F 203-mediated increases in intracellular ROS to suggest the presence of a positive feedback loop. 5F 203 induced oxidative DNA damage in breast cancer cells but not breast epithelial MCF-10A cells unlike AhR agonist benzo[a]pyrene which induced oxidative DNA damage more indiscriminately. Pretreatment with p38 or JNK inhibitors suppressed 5F 203-induced single strand break formation and cytoglobin mRNA expression in breast cancer cells. Our data show 5F 203 confers anticancer activity in breast cancer cells in part by increasing ROS via a positive feedback loop to sustain p38 and JNK activation resulting in DNA damage and cytoglobin restoration.

Citation Format: Leah K. Rowland, Lancelot S. McLean, Petreena Campbell, Cheri N. Watkins, Dain Zylstra, Louisa H. Amis, Maheswari Senthil, Eileen Brantley. Aryl hydrocarbon receptor agonist 5F 203 induces oxidative stress triggering DNA damage and cytoglobin up-regulation in human breast cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2565. doi:10.1158/1538-7445.AM2015-2565
Abstract 2600: Targeting cancer stem cell through blocking the Erk pathway with Kazinol-E from Broussonetia kazinoki
Authors: Jung Yu-Chae , Han Seula , Hua Li , Zhao Hui-Yuan , Lee Cheol-Jung , Cho Yong-Yeon , Jeon Raok , Ryu Jae-Ha , Kim Woo-Young
Published: August 2015

Growing evidence suggests that a small population of cells, called cancer stem cells (CSCs) contribute to the heterogeneity, recurrence and resistance to chemotherapy in breast cancer. In this regard, CSC is considered to be a good target to cure breast cancers. The extracellular signal-regulated kinase (ERK) signaling pathway is one of the major determinants in the control of diverse cellular process including the maintenance of CSCs. Kazinol-E is an antioxidant flavan purified from the root bark of Broussonetia kazinoki (Moraceae, paper mulberry). In this study, we found the anti CSC effect of Kazinol-E through targeting ERK pathway. It decreased the population of a breast cancer cell (MCF-7) CSCs which are CD44+/CD24- or aldehyde dehydrogenase positive, at the concentration that does not influence the growth of general MCF-7 cells cultured with serum. It targeted and inhibited ERK kinase activities in vivo in both CSC and in regular cultured cells suggesting the CSCs depend more than the rest of cancer cells do on Erk signaling for the survival. In vitro kinase assay using purified Erk-1 and p90RSK2, as the substrate, and the molecular docking study suggest that the Kazinol-E suppress the Erk activity by direct binding to the ATP binding pocket of Erk-1. Interestingly, a Kazinol-C which is very similar with Kazinol-E in structure did not show the Erk-1 inhibition nor anti CSC activity. These results collectively suggest that Kazinol-E may be a specific anti CSC agent targeting Erk pathway.

Citation Format: Yu-Chae Jung, Seula Han, Li Hua, Hui-Yuan Zhao, Cheol-Jung Lee, Yong-Yeon Cho, Raok Jeon, Jae-Ha Ryu, Woo-Young Kim. Targeting cancer stem cell through blocking the Erk pathway with Kazinol-E from Broussonetia kazinoki. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2600. doi:10.1158/1538-7445.AM2015-2600
Abstract 2617: SUMOylation inhibition attenuates the cancer stem cell population in glioblastoma and basal breast cancer
Authors: Park Jung M. , Wu Tong , Van Dorin Sarah , Weigel Ronald
Published: August 2015

INTRO: TFAP2A and mouse homolog Tcfap2a are transcription factors that play a critical role in development and cancer. We have recently shown that SUMOylation of TFAP2A is a key posttranslational modification that maintains the basal breast cancer phenotype. Treatment with anacardic acid (AA), a SUMOylation inhibitor, led to depletion of the CD44+/hi/CD24-/lo cancer stem cell population. Interestingly, glioblastoma has also been shown to express TFAP2A and demonstrates an expanded cancer stem cell population.

METHODS: Mouse 4T1 basal mammary cancer, IOWA-1T human basal breast cancer and UG118 glioblastoma cell lines were analyzed. MTT was used to measure cell viability. Coulter Counter and hemocytometer were used for cell quantification. Matrigel invasion and western blot were used to further characterize the cell lines.

RESULTS: Treatment of 4T1 and UG118 cells with AA in vitro resulted in a 67% and 65% decrease in cell viability by MTT assay, respectively (p < 0.05 for both). Quantification of cell number confirmed that AA treatment inhibited cell proliferation. At 48 hours, 4T1 cells demonstrated a decrease of 73-77% (p < 0.01), and UG 118 cells decreased by 97 to 98% (p < 0.001). Cell invasiveness assessed by Matrigel invasion assay was attenuated in 4T1 and UG118 cells after treatment (84%, p < 0.01 and 28%, p < 0.05, respectively). Western blot demonstrated a dose-dependent decrease in expression of the cancer stem cell marker CD44 or the mouse homolog CD49f following AA treatment of UG118 and 4T1 cells, respectively. Western blot confirmed that while total TFAP2A levels were unchanged, SUMO conjugated TFAP2A was decreased after AA treatment of 4T1 cells. To further establish relevance to human cancer, an aggressive chemotherapeutic resistant patient-derived xenograft, IOWA-1T, similarly demonstrated a 41% drop (p < 0.007) in cell invasiveness and a concomitant decrease in SUMOylated TFAP2A with AA treatment.

CONCLUSION: Inhibition of the SUMO pathway attenuates the cancer stem cell population in basal breast cancer and glioblastoma. While further investigation is needed, SUMOylation may be a common biological posttranslational modification that defines cancer stem cells. Furthermore, basal breast cancer, brain cancer, and other cancers that express TFAP2A may be amenable to SUMOylation inhibitors such as AA.

Citation Format: Jung M. Park, Tong Wu, Sarah Van Dorin, Ronald Weigel. SUMOylation inhibition attenuates the cancer stem cell population in glioblastoma and basal breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2617. doi:10.1158/1538-7445.AM2015-2617
Abstract 2635: Targeting HER3 by interfering with its Sec61-mediated cotranslational insertion into the endoplasmic reticulum
Authors: Ruiz-Saenz Ana , Sandhu Manbir , Carrasco Yazmin , Maglathlin Rebecca L. , Taunton Jack , Moasser Mark M.
Published: August 2015

There is increasing evidence implicating HER3 in several types of cancer, as a resilient copartner for HER2 in HER2-amplified cancers, and as a driver of resistance in many other types of cancer. However, the development of targeted therapies to inactivate HER3 function has been a challenging endeavor. Its tumor-driving functions are only sometimes driven by ligand-activation, and targeting its extracellular domain with antibody molecules has only limited effects. Its kinase domain functions in allostery, not catalysis, and we have previously shown that the classical ATP-analog class of tyrosine kinase inhibitors fail to inactivate it. Here we describe a novel approach that eliminates HER3 expression. This involves interfering with mechanisms critical for its cotranslational translocation into the endoplasmic reticulum (ER), resulting in the elimination of HER3 protein expression and loss of HER3 function. The small-molecule cotransin CT8 binds the Sec61 translocon channel in the ER membrane and prevents the signal peptide of the nascent HER3 protein from initiating its cotranslational translocation into the lumen of the ER, resulting in the degradation of HER3. Interestingly, CT8 treatment prevents HER3 translocation while the other HER proteins are unaffected. In addition, CT8 treatment suppresses the compensatory induction of HER3 that accompanies lapatinib treatment of HER2-amplified cancer cells, making for a durable suppression of HER2-HER3 signaling with the lapatinib-CT8 combination. Consistent with the effective inactivation of HER2-HER3 signaling, CT8 treatment synergistically enhances the apoptotic effects of lapatinib in HER2-overexpressing cancer cells. The target selectivities of cotransins are highly dependent on their structure and the signal sequence of targeted proteins and can be narrowed through structure-function studies. Our results thus highlight Sec61-dependent processing as a novel strategy to eliminate HER3 expression and function with considerable potential for the treatment of HER2-amplified and other types of cancers.

Citation Format: Ana Ruiz-Saenz, Manbir Sandhu, Yazmin Carrasco, Rebecca L. Maglathlin, Jack Taunton, Mark M. Moasser. Targeting HER3 by interfering with its Sec61-mediated cotranslational insertion into the endoplasmic reticulum. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2635. doi:10.1158/1538-7445.AM2015-2635
Abstract 2662: A dual PI3K/mTOR inhibitor as potential therapeutic option for vulvar cancer
Authors: Rodrigues Iara , Rodrigues Bruna , Giudice Fernanda , Baiocchi Glauco , Soares Fernando Augusto , Martins Vilma , Rocha Rafael Malagoli
Published: August 2015

Introduction: Epithelial to mesenchymal transition (EMT) is an important process during cancer progression by which epithelial cells acquire mesenchymal phenotype and show reduced intercellular adhesion as well as increased motility. Interfering PI3K/AKT pathway has been considered an anti-EMT target therapy, due to its effect in restoration of E-cadherin function and inhibition of transcription factors that repress the E-cadherin promoter, such as Snail, Slug, and Twist. Aim: Investigate the antitumor effects of treatment with PI3K/mTOR dual inhibitor, NVP-BEZ235, in biological behavior of lymph node metastatic vulva cancer cell line (SW962), as a potential anti-EMT agent in vulvar tumor. Methods: we performed in vitro assays and evaluated the expression of proteins related to PI3K/Akt/mTOR pathway as well as Vimentin and E-cadherin, relevant EMT biomarkers. All results were presented as mean standard deviation and were compared using the unpaired t test or ANOVA followed by the Bonferroni post test using Graph Pad InStat v3.02 software. P values < 0.05 were considered statistically significant. Results: Treatment with NVP-BEZ235 resulted in a significant decrease in cell migration (p< 0.001), proliferation (p< 0.01) and invasion (p<0.05). The phosphorylation of AKT, S6K, 4E-BP1 and p70S6 was markedly reduced by NVP-BEZ235 treatment. In contrast, the levels of p-GSK3β (Ser9) were increased. Our qualitative results demonstrated that the localization pattern of E-cadherin and Vimentin protein was similar between control and treatment groups. We observed Vimentin protein only in isolated cells and, E-cadherin protein was found exclusively in cell clusters, demonstrating EMT-like events in SW962 cells. The expression of E-cadherin in SW962 cells treated was slightly increased and the levels of Vimentin was reduced in these cells. Conclusion: The present study suggests that NVP-BEZ235 is an effective inhibitor of PI3K/mTOR pathway, resulting in the decrease of Vimentin expression, an important EMT marker, as well as of other essential tumor events, such as proliferation, migration and invasion of vulva cancer. Taken together, these findings not only provide a novel insight into the actions of NVP-BEZ235 as inhibitor of EMT process in cancer progression, but also highlight a novel potential therapeutic option for the treatment of aggressive tumors such as vulvar carcinoma.

Citation Format: Iara Rodrigues, Bruna Rodrigues, Fernanda Giudice, Glauco Baiocchi, Fernando Augusto Soares, Vilma Martins, Rafael Malagoli Rocha. A dual PI3K/mTOR inhibitor as potential therapeutic option for vulvar cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2662. doi:10.1158/1538-7445.AM2015-2662
Abstract 2667: FP-208, a novel mTOR inhibitor with potent antitumor activities
Authors: Du Zhenjian , Ji Qi , Chen Bo , Zhang Chunxiao , Zhao Ge , Zhang Xingmin
Published: August 2015

The mammalian target of rapamycin (mTOR) is a master regulator of cell growth, proliferation and survival. The phosphatidylinositol 3-kinase (PI3K)/mTOR pathway is commonly dysregulated in cancer. FP-208, animidazolone derivatives, is a novel small molecule that primarily inhibits mTOR with potent antitumor activity. The compound is soluble with a good oral PK profile and excellent bioavailability in mice and rats. Here we report the in vitro and in vivo effects of FP-208 in multiple cancer cell lines and in xenograft tumor models. FP-208 inhibited mTOR enzymatic activity in vitro (IC50 = 0.3nM) in a kinase assay and cell proliferation in multiple cancer cell lines. Western blot analysis to examine the effect of FP-208 showed significant blockade of phosphorylation of S6 and AKTS473, suggesting inhibition of both mTORC1 and mTORC2 activities. The antitumor activity of FP-208 was evaluated in human cancer xenograft models as well. Oral administration of the compound in tumor bearing mice strongly inhibited tumor growth as a single agent. Further analysis demonstrated that treatment with FP-208 inhibited phosphorylation of mTORC1/2 pathway markers, S6 and AKTS473 in the tumors. Taken together, our data from both in vitro and in vivo studies suggest that FP-208 is a drug candidate for the treatment of human cancers.

Citation Format: Zhenjian Du, Qi Ji, Bo Chen, Chunxiao Zhang, Ge Zhao, Xingmin Zhang. FP-208, a novel mTOR inhibitor with potent antitumor activities. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2667. doi:10.1158/1538-7445.AM2015-2667
Abstract 2679: Overexpression of Mcl-1 confers resistance to BRAFV600E inhibitors alone and in combination with MEK1/2 inhibitors in melanoma
Authors: Fofaria Neel M. , Frederick Dennie T. , Sullivan Ryan J. , Flaherty Keith T. , Srivastava Sanjay K.
Published: August 2015

Melanoma harboring BRAF mutations frequently develop resistance to BRAF inhibitors, limiting the impact of treatment. The most prevalent mechanisms of acquired resistance appear to reactivate MAPK pathway. Furthermore, relatively little is known about the determinants of de novo resistance. Here, we establish such a mechanism of resistance and subsequently identified a suitable drug combination to overcome the resistance. Single treatment of BRAF mutant melanoma cell lines with vemurafenib or dabrafenib (BRAF inhibitors) alone or in combination with trametinib (MEK1/2 inhibitor) resulted in overexpression of Mcl-1. Overexpression of Mcl-1 in A375 and SK-MEL-28 by transfection completely blocked BRAF and MEK1/2 inhibitor-mediated inhibition of cell survival. Melanoma cells resistant to BRAF inhibitors showed massive expression of Mcl-1 as compared to respective sensitive cell lines. Silencing of Mcl-1 using siRNA completely sensitized resistant melanoma cells to growth suppression by BRAF inhibitors. In vivo, vemurafenib resistant A375 xenografts implanted in athymic nude mice showed substantial tumor growth inhibition when treated with a combination of vemurafenib and Mcl-1 inhibitor or siRNA. Immunohistochemistry and western blot analyses demonstrated enhanced expression of Mcl-1 and activation of ERK1/2 in vemurafenib-resistant tumors whereas level of Mcl-1 or p-ERK1/2 was diminished in the tumors of mice treated with either of the combination. Biopsied tumors from the patients treated with or resistant to BRAF inhibitors revealed overexpression of Mcl-1. These results suggest that the combination of BRAF inhibitors with Mcl-1 inhibitor may have therapeutic advantage to melanoma patients with acquired resistance to BRAF inhibitors alone or in combination with MEK1/2 inhibitors. [Supported in part by R01 grant CA129038 (to S.K.S) awarded by the National Cancer Institute].

Citation Format: Neel M. Fofaria, Dennie T. Frederick, Ryan J. Sullivan, Keith T. Flaherty, Sanjay K. Srivastava. Overexpression of Mcl-1 confers resistance to BRAFV600E inhibitors alone and in combination with MEK1/2 inhibitors in melanoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2679. doi:10.1158/1538-7445.AM2015-2679
Abstract 2682: Melanoma phenotype switching to adapt to BRAF inhibition
Authors: Robert Lidia , Tsoi Jennifer , Garcia Diaz Angel , Homet Moreno Blanca , Truong Nhat , Graeber Thomas , Ribas Antoni
Published: August 2015

Melanoma can adapt to several stress factors, such as TNF treatment, by changing its phenotype from a highly differentiated (MITF and MART-1 positive) to undifferentiated (neural crest markers) states. We studied this phenomenon as a mechanism of adaptive resistance to BRAF inhibition since melanomas with both MITF high and low have been reported to result in BRAF inhibitor resistance. We treated 17 BRAFV600E mutant melanoma cell lines with the BRAF inhibitor vemurafenib for short term (3 days) or long term (17 days), and compared them to no treatment or TNF treated conditions. We profiled them phenotypically for MART1 antigen (differentiated phenotype) and nerve growth factor receptor (NGFR, neural crest phenotype) expression by flow cytometry. Results comparing median fluorescence intensity (MFI) showed a wide spectrum of adaptive responses to short term BRAF inhibition, followed by solidification or further evolution of these changes upon long term exposure and development of drug tolerance. According to each cell line distribution, we calculated a (x,y) value that organized the cell lines and conditions in four quadrants according to MART1 (x axis) or NGFR (y axis) expression. Two double negative (MART1-/NGFR-) cell lines that were unaffected by treatment and stayed in the same quadrant. Seven MART1-/NGFR+ and four MART1+/NGFR- cell lines slightly changed phenotype with vemurafenib exposure but stayed in the same quadrant. Four cell lines with MART1+/NGFR+ phenotype were greatly influenced by treatment, showing wide plasticity with cells shifting towards NGFR+/MART1- and others towards NGFR-/MART1+. Changes in position between baseline and tolerance to vemurafenib after 17days treatment were numerically quantified as an inferred number from plasticity. Cell lines with double positive (MART1+/NGFR+) phenotype had a significant change in plasticity compared to the rest of cell lines in other quadrants (p = 0.0004). This arranges cells in a four-quadrant pattern that could be likened to a U-turn toward de-differentiation. Cells that de-differentiated with BRAF inhibition mimicked the effect induced by TNF. This effect was driven by a decrease in MITF activity confirmed with a tyrosinase promoter-luciferase assay. In conclusion, baseline melanoma differentiation phenotypes guide the phenotype switch response, with those double positive for differentiation and neural crest markers being at a semi-stable state that can be prone to different plastic changes upon BRAF inhibition.

Citation Format: Lidia Robert, Jennifer Tsoi, Angel Garica Diaz, Blanca Homet Moreno, Nhat Truong, Thomas Graeber, Antoni Ribas. Melanoma phenotype switching to adapt to BRAF inhibition. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2682. doi:10.1158/1538-7445.AM2015-2682
Abstract 2694: Esophageal cancer exhibits a resistance to the chemical inhibition of IGF-1R with a maintained Ras-MAPK activity
Authors: Takaoka Munenori , Bao XiaoHong , Hao Huifang , Ishida Naomasa , Fukazawa Takuya , Yamatsuji Tomoki , Haisa Minoru , Naomoto Yoshio
Published: August 2015

The type 1 insulin-like growth factor receptor (IGF-1R) and its associated signaling system play a significant role in carcinogenesis and progression of gastrointestinal malignancies, and thus have provoked great interest as a promising target for cancer treatment. The aim of our study was to assess the effects of a novel IGF-1R inhibitor, NVP-AEW541, on the cell proliferation and signal transduction of esophageal squamous cell carcinoma. Five human esophageal squamous carcinoma cell lines (TE-1, TE-4, TE-8, TE-10 and T.Tn) were treated with this inhibitor and the IC50 of NVP-AEW541 for each cell line was more than 1μM, exhibiting that these cells were less sensitive to this compound. The activation of IGF-1R and AKT were dose dependently blocked by NVP-AEW541. However, the activities of the key molecules in Ras-MAPK pathway was not significantly inhibited by NVP-AEW541 without any major mutation of Ras. These results indicate that esophageal squamous cell carcinoma may be resistant to targeting IGF-IR due to its maintenance of Ras-MAPK signaling. Thus, to explore the potential mechanism of resistance will contribute to the therapeutic application for NVP-AEW541.

Citation Format: Munenori Takaoka, XiaoHong Bao, Huifang Hao, Naomasa Ishida, Takuya Fukazawa, Tomoki Yamatsuji, Minoru Haisa, Yoshio Naomoto. Esophageal cancer exhibits a resistance to the chemical inhibition of IGF-1R with a maintained Ras-MAPK activity. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2694. doi:10.1158/1538-7445.AM2015-2694
Abstract 2696: Arenobufagin targets K-Ras downstream to enhance the efficiency of gemcitabine in human pancreatic carcinoma cells
Authors: Wang Tianjiao , Yuan Yuhui
Published: August 2015

Pancreatic carcinoma (PC) is a deadly form of cancer with poor overall survival. Currently, chemotherapeutic such as gemcitabine and 5-fluorouracil (5-FU) are the most popular medication that can slightly improve survival, but rapid drug-resistance makes it urgent to search for more effective drugs. In hunting for natural components that cure PC, we found that arenobufagin, a cardiac glycosides-like compound, showed significant effects on the gemcitabine-resistant cell line Panc-1, the gemcitabine-sensitive cell line ASPC-1 and K-Ras activating HPNE cells at nanomolar concentrations. We used MTT and clonogenic survival assays to examine survival and proliferation and western blotting to assess changes of K-Ras downstream and apoptosis related proteins. We also detected the cell cycle and migration by flow cytometry and wound healing assay. Arenobufagin inhibited cellular survival and proliferation, decreased the phosphorylation of key proteins of K-Ras downstream such as Akt, Erk and nuclear factor kappa B (NF-κB), induced cell cycle G2/M arrest and apoptosis, and downregulated the level of phosphorylated epidermal growth factor receptor (EGFR). Most importantly, our data showed that arenobufagin can enhance the sensitivity of PC cells to gemcitabine and 5-fluorouracil (5-FU). Arenobufagin could enhance the effect of gemcitabine and 5-FU on PC cells through targeting multiple key proteins. All above makes arenobufagin a novel agent for combination therapy of pancreatic carcinoma.

Citation Format: Tianjiao Wang, Yuhui Yuan. Arenobufagin targets K-Ras downstream to enhance the efficiency of gemcitabine in human pancreatic carcinoma cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2696. doi:10.1158/1538-7445.AM2015-2696
Abstract 2700: The IAP inhibitor Debio 1143 reverses carboplatin resistance in ovarian cancer cells by inducing both apoptosis and necroptosis
Authors: Thibault Benoît , Genre Ludivine , Broca Clothilde , Barbier Maryse , Zanna Claudio , Vuagniaux Grégoire , Delord Jean-Pierre , Couderc Bettina
Published: August 2015

Ovarian cancer remains the most lethal gynecological cancer. The efficacy of conventional chemotherapy with a combination of platinum salts and taxanes is transient because 70 to 80% of patients initially responding to platinum finally relapse. Mechanisms of resistance to carboplatin include a disruption of the balance between key pro-and anti-apoptotic proteins such as the inhibitor of apoptosis protein (IAP) family. Drug mimetics of the endogenous IAP inhibitor SMAC constitute a novel therapeutic approach to overcome apoptosis resistance and are currently in clinical development for cancer treatment.

In this study we tested the ability of the oral IAP inhibitor Debio 1143 to revert carboplatin resistance in three carboplatin-sensitive (OVCAR-3, IGROV-1, A2780S) and three carboplatin-resistant (SKOV-3, A2780R, EFO-21) human ovarian tumor cell lines.

We demonstrated that in vitro Debio 1143 was able to sensitize SKOV-3, EFO-21 and A2780R ovarian tumor cells to carboplatin. In addition, we demonstrated that the combination allowed a full recovery of carboplatin sensitivity in A2780R similar to the sensitive cell line A2780S. The sensitization to carboplatin correlated with an increased induction of apoptosis (Annexin V/PI assay and PARP cleavage) in SKOV-3 and A2780R cells. In EFO-21 cells, Debio 1143 triggered necroptosis as shown by the necroptosis inhibitor necrostatin-1 which was able to suppress Debio 1143-induced cell death with or without carboplatin. Our study shows that in the above human ovarian tumor cell lines Debio 1143 induces degradation of cIAP1 while XIAP levels remain unchanged.

Using a carboplatin-resistant in vivo ovarian tumor mouse model, we further showed that Debio 1143 alone or in combination with carboplatin causes marked regression of subcutaneous SKOV-3 tumors.

Together, our results suggest that Debio 1143 in combination with carboplatin could provide considerable benefit to patients with innate or acquired resistance to carboplatin by acting as a sensitizing agent. Debio 1143 is currently evaluated in combination with carboplatin and paclitaxel in patient with advanced solid malignancies including platinum-refractory ovarian cancer (NCT01930292).

Citation Format: Benoît Thibault, Ludivine Genre, Clothilde Broca, Maryse Barbier, Claudio Zanna, Grégoire Vuagniaux, Jean-Pierre Delord, Bettina Couderc. The IAP inhibitor Debio 1143 reverses carboplatin resistance in ovarian cancer cells by inducing both apoptosis and necroptosis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2700. doi:10.1158/1538-7445.AM2015-2700
Abstract 2708: New approaches to overcome tyrosine kinase inhibitor resistances in chronic myeloid leukemia
Authors: Halbach Sebastian , Wöhrle Franziska U. , Braun Sandra , Brummer Tilman
Published: August 2015

Chronic myeloid leukemia (CML) is driven by the hyperactive fusion kinase Bcr-Abl, generated by a chromosomal translocation between chromosome 9 and 22. This oncogenic tyrosine kinase builds up its own signaling network with various proteins such as the docking protein Gab2 or the Src kinase Lyn. As a result, the cells become addicted to the constant signals derived from this fusion kinase. This is the reason why selective Bcr Abl tyrosine kinase inhibitors (TKIs), such as Imatinib mesylate or dasatinib, became so successful in the therapy of CML. Despite the great success of these TKIs in CML treatment, TKI resistance remains a serious clinical problem. These resistances can be caused by mutations in the Bcr-Abl oncogene, like the clinical relevant T315I mutation or by aberrant activity of components of the Bcr-Abl signaling network. In that regard, we could show that the overexpression of Gab2 or the expression of a hyperactive mutant of Lyn can confer TKI resistance.

Using different CML cell lines and models we aimed to identify new approaches to overcome TKI resistances caused by Bcr-Abl mutations or aberrant downstream signaling. Therefore, we screened inhibitors for their ability to overcome Gab2 mediated resistance or to inhibit the activity of T315I mutated Bcr-Abl. We identified the multikinase inhibitors sorafenib and axitinib, both clinical approved as second line drugs in renal cell or hepatocellular carcinoma, as compounds reducing the viability of Bcr-AblT315I transformed cells. Interestingly, these inhibitors were highly active against TKI resistant Bcr-Abl positive cells in contrast to non-transformed cells. These results invite for the further evaluation of sorafenib and axitinib in the treatment of TKI-resistant CML.

Citation Format: Sebastian Halbach, Franziska U. Wöhrle, Sandra Braun, Tilman Brummer. New approaches to overcome tyrosine kinase inhibitor resistances in chronic myeloid leukemia. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2708. doi:10.1158/1538-7445.AM2015-2708
Abstract 272: Checkpoint inhibitor combinations in a human mixed leukocyte reaction
Authors: Sult Erin , Hay Carl , Huang Qihui , Fuhrmann Stacy , Hollingsworth Robert , Sachsenmeier Kris F.
Published: August 2015

In an effort to identify effective target combinations, molecules specific for several immuno-oncology targets were combined in vitro using a mixed leukocyte reaction (MLR) assay. Briefly, 20 different healthy human peripheral blood mononuclear cell donor pairs were tested for proliferation and cytokine release in the presence of each molecule alone and in combination. The collection of agents targeted CTLA-4, PD-1, PD-L1, and CD73. Examples of significant (p<0.05) synergy as well as antagonism and additivity were observed. In addition the phenotype and genotype of the MLR donor PBMCs were characterized. The results from this study are significant for at least two reasons: 1) In contrast to murine syngeneic models they represent aspects of multiple different human donor “immune responses” and 2) In contrast to purified T-cell assays they represent an assay system in which both the lymphoid and myeloid/innate immune compartments play a crucial role, and so better recapitulate a physiological T-cell response. Furthermore, these results provide information at the human population level, offering a glimpse of “responder” and “non-responder” population profiles. This information is impossible to obtain from the currently available collection of syngeneic mouse models.

Citation Format: Erin Sult, Carl Hay, Qihui Huang, Stacy Fuhrmann, Robert Hollingsworth, Kris F. Sachsenmeier. Checkpoint inhibitor combinations in a human mixed leukocyte reaction. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 272. doi:10.1158/1538-7445.AM2015-272
Abstract 2725: Progesterone promotes estrogen induced mammary tumorigenesis through the activation of nodal and notch signaling
Authors: Pedroza Diego A. , Arumugam Arunkumar , Nandy Sushmita , Subramani Ramadevi , Boopalan Thiyagarajan , Lakshmanaswamy Rajkumar
Published: August 2015

Nodal and Notch are considered to be important embryonic morphogens, regulating cell - cell communication, determining left - right asymmetry and in formation of the mesoderm. Cellular processes in embryogenesis can be compared to processes occurring during tumorigenesis. Nodal has been shown to re emerge in aggressive triple negative breast carcinomas, and Notch is known to promote breast cancer. The role of Nodal and Notch in breast carcinomas is being studied; however hormonal regulation of theses two cancer-promoting genes is unknown. Ovarian hormones Estrogen (E) and Progesterone (P) play a vital role in the normal development and function of breast tissue, while extensive exposure to these hormones increases the risk of breast cancer. Studies conducted by the Women's Health Initiative (WHI) have demonstrated that combined Hormone Replacement Therapy (HRT) increases breast cancer risk. The objective of this study is to determine whether P promotes E induced mammary tumorigenesis through the activation of Nodal and Notch signaling. To study the molecular mechanism, MCF-7 cells were cultured and treated with hormones: E, P, E+P and E+Mifepristone (MP - a progesterone antagonist). MTS assay for cellular proliferation, PCR array for gene expression, and western blot for protein expression, were performed. MTS assay showed increased cell proliferation of MFC-7 hormone treatment E+P when compared to control. PCR array analysis showed significant alteration of genes associated with Nodal signaling, specifically Lefty in E+MP treatment, protein expression analysis showed activation of Notch and up - regulation of its downstream targets HES1 and HEY1 with E and P individual and combination treatments while it was down regulated in E+MP treatment. Based on our findings, we suggest that P mediates E induced mammary tumorigenesis through the activation of Nodal and Notch signaling, proposing a possible crosstalk between both pathways in the development and progression of breast cancer.

Citation Format: Diego A. Pedroza, Arunkumar Arumugam, Sushmita Nandy, Ramadevi Subramani, Thiyagarajan Boopalan, Rajkumar Lakshmanaswamy. Progesterone promotes estrogen induced mammary tumorigenesis through the activation of nodal and notch signaling. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2725. doi:10.1158/1538-7445.AM2015-2725
Abstract 2734: Ethanol potentiates tobacco smoke carcinogens-induced MAPK activation
Authors: Pandey Manoj K. , Mukherjee Jagat J. , Desai Dhimant H. , Amin Shantu G. , Kumar Subodh
Published: August 2015

Alcohol consumption along with smoking is a well-known health hazard to human. How alcohol consumption potentiates the smoking mediated hazard is not clear. Previously we reported that DNA damage caused by tobacco smoke carcinogen (+/-) anti-benzo[a]pyrene-7, 8-diol-9,10-epoxide [BPDE] is responded by cells through induction of cell growth inhibition in different cell lines. Here we observed that ethanol (EtOH) treatment at physiologically relevant concentration (60mM) increases the DNA synthesis in DNA damaging carcinogen (BPDE) treated cells. BPDE treatment of cells elicits G1-S cell cycle arrest, but EtOH does not have any significant modulating effect of G1-S arrest, indicating increased DNA synthesis by EtOH is due to modulation of some other signaling event(s). We observed that EtOH co-treatment/ pretreatment potentiates BPDE induced phosphorylation and activation of extracellular regulated kinase 1/2 (ERK1/2). Interestingly, treatment of cells with MEK1 inhibitor (PD09059) significantly reduced EtOH's ability to increase DNA synthesis in BPDE treated cells. All together, these findings suggest that the ability of EtOH to potentiate BPDE-induced ERK activation may potentiates PAH-induced tumorigenesis. [Supported by NIH grant # R03 ES021779].

Citation Format: Manoj K. Pandey, Jagat J. Mukherjee, Dhimant H. Desai, Shantu G. Amin, Subodh Kumar. Ethanol potentiates tobacco smoke carcinogens-induced MAPK activation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2734. doi:10.1158/1538-7445.AM2015-2734
Abstract 2736: Analysis of ROS concentration in serous ovarian carcinoma
Authors: Cohen Shakeria L. , Mehbari Sharifeh , Partridge Edward E. , Aikhionbare Felix
Published: August 2015

Serous ovarian cancer is the most malignant form of cancer affecting the female reproductive tract. Early detection is associated with 90% five year survival however, current screening tools are not sensitive enough to detect ovarian cancer at early stages. Thus, there remains a critical need for advanced diagnositic tools for early detection and improved prognosis. An accumulation of ROS compounds coupled with increased oxidative stress over time can be deleterious and has been implicated in many human diseases including serous ovarian cancer. Evalution of the ROS concentration in different stages of serous ovarian cancer could be helpful in understanding of the different signaling pathways that may be involved in the transformations of ovarian tumor tissue phenotype. In this study the production of ROS compounds were evaluated in the mitochondria as a caustic of oxidative stress that involve in the transformations of serous ovarian carcinoma. Through the use of a fluorogenic probe, dichlorodihydrofluorescin (DCFH-DiOxyQ) that reacts with the free radicals in a sample, cumulative level of ROS concentrations among stages of serous ovarian carcinoma were detected. Results revealed an increase of 25% ROS fluorescence in the malignant stages compared to normal/surrounding tissues samples. Additionally there was a notably higher ROS concentration in the malignant stages compared to the borderline tissue samples. Results from this study indicate an exponential increase in the levels of ROS from the benign to malignant stages of the disease, suggesting that cumulative ROS levels from early to late of stages may be involved in the progressive stages of the serous ovarian disease type.

Citation Format: Shakeria L. Cohen, Sharifeh Mehbari, Edward E. Partridge, Felix Aikhionbare. Analysis of ROS concentration in serous ovarian carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2736. doi:10.1158/1538-7445.AM2015-2736
Abstract 2737: Dynamics of Epstein-Barr virus loss in the live epithelial cells
Authors: Zhou Yuan , Tsao George
Published: August 2015

Epstein-Barr virus (EBV) infection is highly associated with not only lymphoma but also some solid tumour such as nasopharyngeal carcinoma (NPC) and gastric adenocarcinoma. Previous study found that EBV genomes were present in all of NPC cells in vivo, however they lost rapidly during in vitro cell culture. Previously, because it was difficult to label the EBV DNA with fluorescence protein in the nuclear, the mechanism for EBV loss has not been well studied. In present study, we confirmed in the immortalized nasopharyngeal epithelial cells that the percentage of EBV positive cells decreased rapidly after infection. In addition, we infected epithelial cells with recombinant EBV particles that could be visualized as fluorescent signals after entering host nuclear. We further monitored the dynamics of EBV in host nucleus at single cell level by live cell imaging. We found that inefficient replication and uneven partition may contribute to the EBV loss in epithelial cells. In conclusion, our data provides quantitative information about the dynamics of EBV plasmids in epithelial cells at single cell level. This information will shed light to uncover the mechanism for EBV loss after infection in epithelial cells. This work is supported in part by grants from GRF, HKU 779713M and HKU779312M.

Citation Format: Yuan Zhou, George Tsao. Dynamics of Epstein-Barr virus loss in the live epithelial cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2737. doi:10.1158/1538-7445.AM2015-2737
Abstract 2743: Cancer risk in relatives of testicular cancer patients by histology type and age at diagnosis: a joint study from five Nordic countries
Authors: Kharazmi Elham , Hemminki Kari , Pukkala Eero , Sundquist Kristina , Tryggvadottir Laufey , Tretli Steinar , Olsen Jørgen H. , Fallah Mahdi
Published: August 2015

Background: None of population-based epidemiological studies to date had a large enough sample size to show familial risk of testicular cancer (TC) by patients’ and their relatives’ age at diagnosis and also by rare histological subtypes.

Objective: We aimed to estimate absolute and relative risk of TC in relatives of TC patients by age at diagnosis in patients and their relatives and histology subtypes.

Design: A joint population-based cohort study.

Setting and Participants: A cohort of 97,402 first-degree relatives of 21,254 TC patients who were diagnosed between1955 and 2010 in five European countries was followed for cancer incidence.

Outcome Measurements and Statistical Analysis: Standardized incidence ratios (SIRs) were estimated using histology-, age-, period-, and country-specific incidence rates as the reference. The lifetime cumulative risks also were calculated.

Results and Limitations: The lifetime cumulative risk of TC in brothers of a patient with TC was 2.3%, which represents 4-fold increased risk (SIR = 4.1, 95%CI = 3.6-4.6) over the general population risk. TC in a father increased the risk up to 2-fold in his son (95%CI = 1.7-2.4; lifetime risk 1.2%) and vice versa. When there were ≥2 TC patients diagnosed in a family, lifetime TC risk for relatives was 10-11%. Depending on age at diagnosis, twins had 9-74% lifetime risk of TC. Family history of most of the histological subtypes of TC increased the risk for concordant and most of the discordant subtypes. There was a tendency toward concordant age at diagnosis of TC among relatives.

Conclusions: This study provides clinically relevant age-specific cancer risk estimates for family members of TC patients. Familial TC cases tended to develop TC at an age close to age at diagnosis of TC among their relatives, which is the novel finding of this study.

Citation Format: Elham Kharazmi, Kari Hemminki, Eero Pukkala, Kristina Sundquist, Laufey Tryggvadottir, Steinar Tretli, Jørgen H. Olsen, Mahdi Fallah. Cancer risk in relatives of testicular cancer patients by histology type and age at diagnosis: a joint study from five Nordic countries. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2743. doi:10.1158/1538-7445.AM2015-2743
Abstract 2746: Significant evidence for linkage for lethal prostate cancer on chromosome arm 4q in Utah high-risk pedigrees
Authors: Cannon-Albright Lisa A. , TEERLINK craig C. , Stephenson Robert A. , Agarwal Neeraj
Published: August 2015

Background: Using the unique Utah genealogical resource that links 12 generations of genealogy data to a statewide cancer registry from 1966 and statewide death certificates from 1904 we have identified a set of high-risk lethal prostate cancer pedigrees with a significant excess of prostate cancer cases having died from prostate cancer.

Methods: Clusters of prostate cancer cases descended from a common ancestor, among whose descendants is observed a statistical excess of prostate cancer (high-risk prostate cancer pedigrees) were recruited and sampled over the past 25 years. Pedigrees including 4 or more cases who have subsequently been reported to have died from prostate cancer (as evidenced by inclusion as a cause of death on a Utah death certificate) were genotyped with 720k high-density SNPs across the genome. Linkage analysis with markers not in linkage disequilibrium was performed to identify regions hypothesized to contain a lethal prostate cancer predisposition gene.

Results: A single extended Utah high-risk prostate cancer pedigree (p<0.05 for significant excess of deceased prostate cancer cases) including 6 distantly related sampled prostate cancer cases who went on to die as a result of their prostate cancer showed significant evidence for linkage at chromosome arm 4q24 (LOD score = +3.28), with 5 of the 6 cases having inherited the same region of chromosome 4 from a common ancestor.

Conclusions: The inability of association studies to identify prostate cancer predisposition genes has returned focus to linkage studies of highly informative high-risk pedigrees, which provide power for identifying and localizing regions of interest for predisposition genes. A focus on only those prostate cancer cases who are members of high-risk lethal prostate cancer pedigrees, who also went on to die as a result of their prostate cancer, has resulted in the identification of evidence for a prostate cancer predisposition gene on chromosome arm 4q24, confirming a previous GWAS that reported association with prostate-cancer-specific-survival (Pomerantz MM et al., 2011) in this region harboring TET2 (a tumor suppressor gene involved in pathogenesis of acute myeloid leukemia, myelodysplastic syndrome, and myeloproliferative neoplasms), and PP2A (implicated in androgen receptor regulation in prostate cancer cell lines).

Citation Format: Lisa A. Cannon-Albright, craig C. TEERLINK, Robert A. Stephenson, Neeraj Agarwal. Significant evidence for linkage for lethal prostate cancer on chromosome arm 4q in Utah high-risk pedigrees. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2746. doi:10.1158/1538-7445.AM2015-2746