bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2903: Differential regulation of LC3 A and B, GABARAPL 1 and 2 autophagy genes by micro-environmental stress and role in breast cancer survival
Authors: Zois Christos E. , Haider Syed , Wigfield Simon , Giatromanolaki Alexandra , Sivridis Efthimios , Morten Karl , Roxanis Ioannis , Leek Russell , Buffa Francesca , Koukourakis Michael , Harris Adrian L.
Published: August 2015

The microtubule-associated protein light chain 3 MAP1LC3 (LC3) and GABARAPL1 and 2 are the major proteins to monitor autophagy. Here, we analyzed the role of both MAP1LC3, GABARAPL1 and 2 in breast cancer cells and primary human breast cancer. HER2 amplified (BT474, SKBR3, MDA-MB-453), ER positive (MCF7, T47D) and triple negative (MDAMB231) breast cancer cell lines were studied in response to hypoxia, in high [25mM] and low glucose [5mM] treatment. Low glucose increased the basal levels for LC3A-II, LC3B-II and GABARAPL2-II in BT474, MCF7 and MDAMB231 cell lines. SKBR3 cell line had the lowest autophagic protein levels for LC3B-II, and Gabarapl2-II and was the most resistance to the autophagy inhibition mediated using siRNAs to all theseIn hypoxia both LC3B (up to 8 fold) and GABARAPL1 (up to 12 fold) mRNA expression were induced in all cell lines (p<0.001). MAP1LC3A knockdown significantly decrease cell proliferation in BT474, MCF7 and MDAMB231 while GABARAPL2 knockdown additionally decreased baseline cell proliferation in T47D and SKBR3 breast cancer cells (p<0.05, n = 3). Moreover, using the Seahorse, decreased MAP1LC3A and GABARAPL2 expression by siRNA led to cellular bioenergetic changes including increased basal oxygen consumption of the MCF7.

Co-expression analysis of autophagic genes define distinctive clusters of MAP1LC3, GABARAPL 1 and 2 with the hypoxic signature in breast cancer subtypes using the METABRIC series.

The expression levels of the MAP1LC3 and GABARAPL1 and 2 among the breast cancer subtypes and normal tissue showed significant suppession of all of them in cancer compared to normal breast tissue. In conclusion, all the pathways were suppressed at RNA level in cancer compared to normal, baseline levels were not associated with core classification of breast cancer types. These latter data were confirmed in a breast cancer cell line panel, which showed a marked variation in inducibility by environemntal stress and role in survival under low glucose and hypoxia. Thus analysis of induced gene expression in response to stress may be important, or heterogeneity in selection of tumors for anti-autophagy therapy.

Citation Format: Christos E. Zois, Syed Haider, Simon Wigfield, Alexandra Giatromanolaki, Efthimios Sivridis, Karl Morten, Ioannis Roxanis, Russell Leek, Francesca Buffa, Michael Koukourakis, Adrian L. Harris. Differential regulation of LC3 A and B, GABARAPL 1 and 2 autophagy genes by micro-environmental stress and role in breast cancer survival. [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 2903. doi:10.1158/1538-7445.AM2015-2903
Abstract 2910: The dual role of autophagy in cadmium induced prostate carcinogenesis
Authors: Das Trinath P. , John Arokya MS , Suman Suman , Ankem Murali , Damodaran Chendil
Published: August 2015

Cadmium chloride (Cd) and cadmium products cause both acute and chronic cytotoxicity and Cd exposure correlates with the risk of cancer, especially prostate cancer in humans. On the cellular and molecular level, Cd compounds may promote transformation of healthy cells to a malignant state by inducing expression of pro-survival signaling molecules. However, the precise molecular mechanism by which Cd affects cellular transformation in different tissue types, especially in prostate, is yet to be delineated. Autophagy is an intracellular lysosomal degradation process by which cells remove damaged organelles and maintain the integrity of intracellular components. In cancer cells, autophagy promotes cancer cell survival as well as cell death. It is unclear of how, and under what circumstances, these dual and opposite roles of autophagy affect both anti-oncogenic and oncogenic functions. It is possible that uncharacterized molecular switch that influences the anti-oncogenic function of autophagy in healthy cells to become oncogenic.

In our studies, we found that exposure of normal prostate epithelial cells (RWPE-2) in culture to Cd (10μM) results in growth inhibition. By contrast, the growth of Cd-transformed prostate epithelial (CTPE) cells was not inhibited by the same Cd treatment. While analyzing the molecular link between Cd induced toxicity and generation of reactive oxygen species (ROS) generation in RWPE-2 and CTPE cells; we found there was no significant change in the ROS induction in both cell types. In addition, no changes in the expression of autophagy targeted genes (Atg family proteins) were seen in Cd treated in both non-transformed and transformed cells. However, microtubule-associated protein 1A/1B-light chain 3B (LC-3B), which is directly involved in autophagy initiation was upregulated in Cd-treated non-transformed cells, but not in Cd-treated transformed cells. LC-3B activation also correlated with growth inhibition in non-transformed cells, while impairing LC-3B activation in RWPE-2 cells causes resistance to CD induced growth inhibition. Our ongoing study will determine whether induction of autophagy via LC-3B is a key event that facilitates Cd-mediated conversion of non-transformed prostate epithelial cells to a malignant state. We strongly believe our studies will define a new concept of LC-3B mediated autophagy in Cd-induced prostate carcinogenesis.

Citation Format: Trinath P. Das, Arokya MS John, Suman Suman, Murali Ankem, Chendil Damodaran. The dual role of autophagy in cadmium induced prostate carcinogenesis. [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 2910. doi:10.1158/1538-7445.AM2015-2910
Abstract 2911: Leptin Notch VEGFR-2 axis influences cancer stromal cell behavior
Authors: Lanier Viola , Jeffers Merle , Walterberger Johannes , Anderson Leonard , Gonzalez Ruben
Published: August 2015

PURPOSE: Breast cancer cells induce changes in the stromal environment during malignancy. These changes promote growth, angiogenesis, invasion, and metastasis. The secretion of the adipokine, leptin, from adipose tissue has been shown to contribute to cell proliferation, migration and survival. We previously reported that leptin induces Notch, a pro-survival factor and contributor to the VEGF/VEGFR-2 pro-angiogenic system. We hypothesize that the leptin Notch axis induces activation of fibroblast cells and leads to endothelial cell proliferation, tubule formation, and survival.

These effects could be related to leptin-induced Notch expression and VEGFR-2 transactivation, independent of VEGF.

METHODS: Mouse Embryo Fibroblast cells (NIH/3T3), human umbilical vein endothelial cells (HUVEC) and porcine aorta endothelial cells (PAEC) were challenged with leptin (dose and time-response), and inhibitors of Notch (DAPT) and VEGFR-2 (SU5416 kinase inhibitor). Expression of Notch, VEGFR-2, Ob-R and phosphorylation of VEGFR-2 were determined. The impact of treatment on angiogenic features of endothelial cells was determined. To determine whether leptin-Notch axis activates fibroblast cells, leptin doses 0.6, 1.2, and 6.2 were used. RESULTS: Leptin induced phosphorylation of VEGFR-2 at intracellular site Y1175 and tubule formation in HUVEC. Leptin induced phosphorylation of VEGFR-2 at sites Y951, Y996, Y1059, and Y1175 in PAEC VEGFR2. Protein expression of Notch4 and Jagged1 was induced by leptin treatment in NIH/3t3 cells.

CONCLUSION: Leptin secreted by fibroblast cells and/or adipose tissue may contribute to tumor angiogenesis by acting directly on stromal cells and inducing a VEGFR-2/Notch crosstalk. Novel therapies that target leptin signaling could be a new strategy for the prevention and treatment of breast cancer. These therapies could be more relevant for obese cancer patients with high circulating amounts of leptin.

Citation Format: Viola Lanier, Merle Jeffers, Johannes Walterberger, Leonard Anderson, Ruben Gonzalez. Leptin Notch VEGFR-2 axis influences cancer stromal cell behavior. [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 2911. doi:10.1158/1538-7445.AM2015-2911
Abstract 2917: Caspase-8 expression is predictive of tumor response to death receptor 5 agonist antibody conatumumab in Ewing's sarcoma
Authors: Kang Zhigang , Goldstein D Seth , Yu Yunkai , Meltzer Paul S. , Loeb David M. , Cao Liang
Published: August 2015

Despite good initial response to cytotoxic chemotherapy, approximately 30% of Ewing's sarcoma (EWS) patients who present with localized tumors develop recurrent disease, which is associated with poor prognosis. Addressing this clinical challenge requires the development of targeted therapies. This study shows that many EWS cell lines are selectively sensitive to a death receptor DR5 antibody and are more resistant to a DR4 antibody. Preclinical evaluation of these cell lines indicates their sensitivity to human DR5 agonist antibody conatumumab in vitro, which induces rapid activation of caspase-8 and apoptosis. Further analysis reveals the correlation of sensitivity to conatumumab with the expression of caspase-8, with its catalytic activity both necessary and sufficient to confer such sensitivity. In vivo, conatumumab has active against both EWS cell lines and a patient-derived xenograft with higher caspase-8 expression, but is not effective against another patient-derived xenograft with lower caspase-8 expression. These studies suggest the potential of conatumumab as a therapeutic agent against EWS and caspase-8 as a biomarker for correlative studies.

Citation Format: Zhigang Kang, D Seth Goldstein, Yunkai Yu, Paul S. Meltzer, David M. Loeb, Liang Cao. Caspase-8 expression is predictive of tumor response to death receptor 5 agonist antibody conatumumab in Ewing's sarcoma. [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 2917. doi:10.1158/1538-7445.AM2015-2917
Abstract 2922: Development of Bcl2 BH4 antagonist for cancer therapy
Authors: Han Bingshe , Park Dongkyoo , Li Rui , Xie Maohua , Owonikoko Taofeek , Sica Gabriel , Ding Chunyong , Zhou Jia , Magis Andrew , Ramalingam Suresh , Khuri Fadlo , Curran Walter , Deng Xingming
Published: August 2015

The BH4 domain of Bcl2 is required for its antiapoptotic function, thus constituting a promising anticancer target. We identified a novel small molecule Bcl2-BH4 domain-antagonist (BDA-366) that binds BH4 with high affinity and selectivity. BDA-366-Bcl2 binding induces conformational change in Bcl2 that abrogates its antiapoptotic function, converting it from a survival to a cell death inducer. BDA-366 induces regression of lung cancer xenografts derived from cell line and patient without significant normal tissue toxicity at effective doses. mTOR inhibition up-regulates Bcl2 in lung cancer cells and tumor tissues from clinical trial patients. Combined BDA-366 and RAD001 treatment exhibits strong synergy against lung cancer in vivo. Development of this Bcl2-BH4 antagonist may provide a novel strategy to improve lung cancer outcome.

Citation Format: Bingshe Han, Dongkyoo Park, Rui Li, Maohua Xie, Taofeek Owonikoko, Gabriel Sica, Chunyong Ding, Jia Zhou, Andrew Magis, Suresh Ramalingam, Fadlo Khuri, Walter Curran, Xingming Deng. Development of Bcl2 BH4 antagonist for cancer therapy. [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 2922. doi:10.1158/1538-7445.AM2015-2922
Abstract 2923: A novel cell-penetrating peptide targeting ATF5 (CP-d/n-ATF5) exerts anti-cancer activity in vitro and in vivo against a broad spectrum of human cancers
Authors: Karpel-Massler Georg , Shu Chang , Chau Lily , Angelastro James M. , Greene Lloyd A. , Siegelin Markus D.
Published: August 2015

Background

The purpose of this study was to validate the anti-neoplastic activity of a novel ATF5-targeted therapeutic approach against various recalcitrant human malignancies. Activating transcription factor 5 (ATF5) is a member of the cAMP response element binding (CREB)/ATF subfamily of basic leucine zipper transcription factors and has been shown to be overexpressed in many human cancers. CP-d/n-ATF5 is a novel peptide specifically designed to contain a cell-penetrating domain and a domain inhibiting the function of ATF5 in a unique and novel targeted therapeutic approach. This therapeutic strategy was tested among a large panel of different therapy refractory human cancers including glioblastoma, melanoma, breast, prostate-, lung- and pancreatic cancer.

Methods

Cellular viability was assessed by MTT-assays. The induction of apoptosis was examined by staining for annexin V/propidium iodide or JC-1 (loss of mitochondrial membrane potential) prior to flow cytometric analysis. Western blotting was performed for further molecular analysis detecting caspase cleavage and expression of Bcl-2 family members. Subcutaneous xenograft models were used to examine the anti-neoplastic effects of CP-d/n-ATF5 in vivo.

Results

Our data show that CP-d/n-ATF5 yields a significant increase in apoptosis across a panel of 10 different cancer cell lines when compared to treatment with a mock-mutated control peptide or penetratin. On the molecular level, treatment with CP-d/n-ATF5 resulted in a marked down-regulation of the anti-apoptotic Bcl-2 family members Mcl-1 and Bcl-2. This effect was amplified in a synergistic manner by adding either ABT-263 or TRAIL to a combined targeted therapeutic approach. In vivo, treatment with CP-d/n-ATF5 resulted in a significant reduction of tumor growth in a heterotopic glioblastoma- and an orthotopic melanoma model.

Conclusions

The novel ATF5-targeting compound CP-d/n-ATF5 provides a broad and pronounced anti-neoplastic activity against human cancers in vitro and in vivo. On the molecular level, this effect is at least in part due to a shift of the cellular homeostasis towards a pro-apoptotic cellular phenotype by inhibiting anti-apoptotic Bcl-2 family proteins. Overall, CP-d/n-ATF5 may represent a promising novel anti-cancer agent.

Citation Format: Georg Karpel-Massler, Chang Shu, Lily Chau, James M. Angelastro, Lloyd A. Greene, Markus D. Siegelin. A novel cell-penetrating peptide targeting ATF5 (CP-d/n-ATF5) exerts anti-cancer activity in vitro and in vivo against a broad spectrum of human cancers. [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 2923. doi:10.1158/1538-7445.AM2015-2923
Abstract 2926: DR5-targeting sensitizes Lgr5+ stem cells to p53 and Chk2-dependent chemotherapy-induced cell death and produces dose-limiting gastrointestinal toxicity (GIT)
Authors: Finnberg Niklas K. , Gokare Prashanth , Navaraj Arunasalam , Lang Kuhs Krystle A. , Cerniglia George , Yagita Hideo , Takeda Kazuyoshi , Motoyama Noboru , El-Deiry Wafik S.
Published: August 2015

Current ongoing clinical trials are exploring combined targeting of the TRAIL-death receptor DR5 with radiochemotherapy. It is not clear mechanistically why targeting of the DR5 increasingly sensitizes cancer cells to cell death without affecting cells in normal tissues. Preclinical data suggests that integration of DR5 agonist antibodies into chemotherapy protocols has the promise to significantly improve cancer specific responses without negatively impacting dose-limiting toxicities. Here we show that targeting of DR5 in mice with the mouse-specific mAb MD5-1 in combination with chemotherapy triggers synergistic gastrointestinal toxicities (GIT) that is associated with the death of Lgr5+ crypt basal columnar (CBC) cells. This type of GIT is mediated by p53 and in the case of irinotecan, the cell cycle checkpoint kinase 2 (Chk2). Pharmacologic targeting of Chk2 sensitized syngeneic mouse colorectal cancer tumors lacking P53 to the irinotecan/MD5-1 combination while at the same time protecting the gastrointestinal tract from injury. Our data indicates that blockade of cell cycle checkpoint kinases can help prevent GIT triggered by a combination of DNA damaging chemotherapy and DR5 agonists. Pharmacologic targeting of Chk2 can improve the anti-tumor response of such drug combinations and subsequently provides a rationale on how to improve therapeutic indices of DR5-targeting in the context of chemotherapy usage.

Citation Format: Niklas K. Finnberg, Prashanth Gokare, Arunasalam Navaraj, Krystle A. Lang Kuhs, George Cerniglia, Hideo Yagita, Kazuyoshi Takeda, Noboru Motoyama, Wafik S. El-Deiry. DR5-targeting sensitizes Lgr5+ stem cells to p53 and Chk2-dependent chemotherapy-induced cell death and produces dose-limiting gastrointestinal toxicity (GIT). [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 2926. doi:10.1158/1538-7445.AM2015-2926
Abstract 2932: Role of death receptor 5 (DR5) in apoptosis induced by anticancer agents in colon cancer cells
Authors: Tong Jingshan , Yu Jian , Zhang Lin
Published: August 2015

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor, also called death receptor 5 (DR5; TRAIL receptor2), is a member of the death receptor family that shares a cysteine-rich extracellular domain and a cytoplasmic death domain. DR5 is located on cell surface, becomes activated upon binding to its ligand TRAIL or overexpression, and then signals apoptosis initiation through an FADD/caspase 8-dependant caspase activation cascade. A number of previous studies showed that DR5 expression is induced upon chemotherapy treatment. However, whether DR5 induction is necessary for apoptosis induction has remained unclear. To determine its functional role in chemotherapy-induced apoptosis, we used homologous recombination to knock out (KO) DR5 in HCT116 colon cancer cells, and then analyzed response of DR5 KO cells to a panel of anticancer agents. Compared to parental HCT116 cells, DR5 KO cells are less sensitive to TRAIL, the DNA damaging drug 5-FU, the non-steroidal anti-inflammatory drug (NSAID) sulindac, as well as several other classes of anticancer agents. We also investigated how these agents induce apoptosis through DR5. Together, our results indicate a critical role of DR5 in mediating therapeutic response of colorectal cancer cells.

Citation Format: Jingshan Tong, Jian Yu, Lin Zhang. Role of death receptor 5 (DR5) in apoptosis induced by anticancer agents in colon 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 2932. doi:10.1158/1538-7445.AM2015-2932
Abstract 2936: Mitochondria dysfunction-mediated apoptosis resistance associates with defective heat shock protein response in African American prostate cancer
Authors: Chaudhary Ajay K. , Bhatt Tariq A. , Kumar Sandeep , Underwood Willie , Koochekpour Shahriar , Shourideh Mojgan , Yadav Neelu , Chandra Dhyan
Published: August 2015

African American (AA) patients with prostate cancer (PCa) respond poorly to current therapy compared to Caucasian American (CA) patients. Although underlying mechanisms are not clearly defined, mitochondria dysfunction is a key reason for PCa disparity. We observed that glycolytic pathway inhibitor dichloroacetate (DCA) inhibited cell proliferation in both AA PCa cells (AA cells) and CA PCa cells (CA cells). CA cells were arrested at G1 and G2/M phases whereas S-phase arrest was observed in AA cells. AA cells showed resistance to cell death upon DCA exposure in spite of higher caspase activation than in CA cells. AA cells possess reduced level of reactive oxygen species (ROS) and mitochondrial membrane potential (mtMP) compared to CA cells. DCA induced cellular and mitochondrial ROS in AA cells but were unchanged in CA cells. DCA upregulated the levels of mtMP in both cell types. DCA enhanced taxol-induced cell death only in CA cells, but DCA sensitized doxorubicin-induced AA cell death. Expression of heat shock proteins (HSPs) were inhibited only in AA cells upon doxorubicin alone or combined treatment of DCA with doxorubicin, whereas Taxol alone or in combination with DCA did not show any changes in the levels of HSPs. DCA suppressed the metastatic features and reduced the population of cancer stem cell-like cells in CA cells but had a little effect on AA cells. Therefore, anticancer agents that can effectively restore mitochondria function may provide new therapeutic potential in reducing PCa health disparity and poor prognosis in AA men with PCa.

Citation Format: Ajay K. Chaudhary, Tariq A. Bhatt, Sandeep Kumar, Willie Underwood, Shahriar Koochekpour, Mojgan Shourideh, Neelu Yadav, Dhyan Chandra. Mitochondria dysfunction-mediated apoptosis resistance associates with defective heat shock protein response in African American prostate 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 2936. doi:10.1158/1538-7445.AM2015-2936
Abstract 2937: MEK/ERK inhibitor GDC-0623 dephosphorylates and accumulates BIM that enables a synergistic apoptosis with the Bcl-xL antagonist, ABT-263, in mutant KRAS colorectal cancer cells
Authors: Zaanan Aziz , Okamoto Koichi , Kawakami Hisato , Huang Shengbing , Sinicrope Frank
Published: August 2015

Background. Oncogenic KRAS mutations occur in nearly one-half of colorectal cancers (CRC) where they contribute to de novo apoptosis resistance and treatment failure. Inhibition of MEK/ERK is a promising strategy to sensitize KRAS mutant tumors to apoptosis that may involve upregulation of pro-apoptotic BH3-only proteins, including BIM. However, BH3-only proteins can be neutralized by anti-apoptotic Bcl-xL that we found was upregulated in isogenic KRAS mutant compared to wild-type HCT116 and DLD1 CRC cells.

Aims. We determined the ability and mechanism by which a novel MEK/ERK inhibitor, GDC-0623, can induce BIM to promote apoptotic signaling. A strategy of concurrent induction of BH3-only proteins and antagonism of Bcl-xL was studied to overcome mutant KRAS-mediated apoptosis resistance.

Results. Using isogenic KRAS HCT116 cells and KRAS mutant SW620 cells, we found that GDC-0623 can potently induce the BH3-only protein BIM, and to a lesser extent BIK, in both KRAS wild-type and mutant cells. Only KRAS mutant cells remained resistant to GDC-0623-induced apoptosis. Knockdown of Bcl-xL or use of a BH3 mimetic drug, ABT-263, sensitized KRAS mutant cells to GDC-0623-mediated apoptosis. GDC-0623 and ABT-263 were shown to interact synergistically to promote apoptosis in KRAS mutant cells. Dependence on BIM or BIK for synergy between GDC-0623 and ABT-263 was shown by shRNA knockdown that each attenuated drug-induced apoptosis. Mechanistically, ABT-263 treatment was shown to release BIM from its binding to Bcl-xL using immunoprecipitation. The ability of GDC-0623 to induce apoptosis occurred via BIM that was phosphorylated by MEK/ERK activation leading to BIM degradation. GDC-0623 was shown to dephosphorylate BIM at serine 69 in cells with wild-type BIM or a phospho-mimic mutation (S69E). However, GDC-0623's ability to dephosphorylate BIM was lost in cells containing a phosphorylation-defective BIM mutation (S69G) that showed delayed BIM degradation.

Conclusion. GDC-0623 was shown to dephosphorylate BIM to enhance its accumulation and to promote apoptosis. Concurrent induction of BIM/BIK and antagonism of Bcl-xL can overcome mutant KRAS-mediated apoptosis resistance, suggesting a promising therapeutic strategy against KRAS mutant CRCs.

Note: This abstract was not presented at the meeting.

Citation Format: Aziz Zaanan, Koichi Okamoto, Hisato Kawakami, Shengbing Huang, Frank Sinicrope. MEK/ERK inhibitor GDC-0623 dephosphorylates and accumulates BIM that enables a synergistic apoptosis with the Bcl-xL antagonist, ABT-263, in mutant KRAS colorectal 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 2937. doi:10.1158/1538-7445.AM2015-2937
Abstract 2938: BMI-1 inhibition by PTC-209 induces mitochondrial apoptosis in acute myeloid leukemia cells
Authors: Kojima Kensuke , Nishida Yuki , Maeda Aya , Chachad Dhruv , Kitamura Hiroaki , Ishizawa Jo , Andreeff Michael , Kimura Shinya
Published: August 2015

Leukemia stem cells play important roles in leukemia initiation, progression, and relapse, and represent a critical target for therapeutic intervention. BMI-1 is essential for the self-renewal of normal hematopoietic and leukemia stem cells. High expression of BMI-1 has been associated with poor prognosis in AML. PTC-209 is a novel transcriptional inhibitor of BMI-1, which has been reported to exhibit antitumor activity against cancer-initiating cells in colorectal cancer. We investigated anti-leukemia effects of the BMI-1 inhibitor PTC-209 on AML cells. A total of 8 AML cell lines (MOLM-13, OCI-AML3, MV4-11, NB4, HL-60, U-937, MOLM-14, OCI-AML2) were treated with different concentrations of PTC-209 for 48 hours and the IC50 values (concentration at which cell growth is inhibited by 50% at 48 hours of exposure) and the ED50 values (effective concentration inducing 50% killing as measured by Annexin V positivity) were determined. The IC50 values were 0.38 ± 0.07 μM (mean ± SEM), indicating high anti-proliferation effect. The ED50 values ranged from 1.2 to 2.6 μM in 7 cell lines (1.97 ± 0.22 μM) and the remaining cell line (NB4) showed relative resistance to PTC-induced apoptosis (> 10 μM). PTC-209 exhibited dose- and time-dependent anti-proliferative and cytotoxic activities, by inducing G1-S transition delay and apoptosis. PTC-209 induced conformational change of BAX (i.e., BAX activation), loss of mitochondrial membrane potential (MMP), caspase-3 activation and DNA fragmentation in addition to phosphatidylserine (PS) externalization, indicating mitochondrial apoptosis. PTC-209 induced Annexin V in primary AML cells (23.4 ± 4.6% after 48-hour treatment with 1 μM PTC-209, n = 23) in a dose-dependent manner, which is more prominent in immature CD34+CD38- population (33.7 ± 6.0%; P = 0.0036). In accordance with its high anti-leukemia activity, PTC-209 strongly reduced cellular BMI-1 levels in CD34+CD38- AML cells. Higher reduction of BMI-1 expression was positively correlated with higher susceptibility to PTC-209 in CD34+CD38- AML cells (r = 0.88; P = 0.047). The apoptotic activity was observed independent of p53 or FLT3 mutational status of the leukemia cells. Our data suggest that BMI-1 inhibition by small molecule inhibitors may be developed into a novel therapeutic strategy for AML. (Drs M. Andreeff and S. Kimura are co-senior authors with equal contribution to the work)

Citation Format: Kensuke Kojima, Yuki Nishida, Aya Maeda, Dhruv Chachad, Hiroaki Kitamura, Jo Ishizawa, Michael Andreeff, Shinya Kimura. BMI-1 inhibition by PTC-209 induces mitochondrial apoptosis in acute myeloid leukemia 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 2938. doi:10.1158/1538-7445.AM2015-2938
Abstract 2939: Induction of apoptosis in prostate cancer cells by altering cell metabolism
Authors: Torga Gonzalo , Mooney Steven , Zarif Jelani C. , Pienta Kenneth J.
Published: August 2015

The levels of ceramides, sphingosine and their related metabolites have been reported to play an important role in cell fate by determining the balance between apoptosis and cell survival signaling through what has been called the sphingolipid rheostat. One of sphingosine metabolic product, sphingosine-1-phosphate, has been widely proven to be related with tumor growth, resistance to apoptosis, angiogenesis, metastasis and invasiveness in several tumors. In prostate cancer, sphingosine-1-phosphate levels correlate with risk of progression to castration-resistant prostate cancer (CRPC), PSA levels, Gleason score, positive surgical margins, lymph node extension, metastatic extension and mortality.

Hypoxia-inducible factors (HIFs) act as pleiotropic transcription factors which serve as major components for cancer progression, upregulation of HIFs are essential for metastasis and tumor growth once hypoxia has ensued. Several relations between HIFs and ceramides/sphingosine metabolism have been reported recently, suggesting that both mechanisms might be somehow interconnected.

Despite decades of research inhibitors to HIF have been few and far between. The DNA-intercalating agent doxorubicin was identified one such inhibitor by a mechanism not yet understood. The major mechanism of doxorubicin-mediated apoptosis has been established to be induced by the transcription factor, p53. The p53 cell cycle arrest is usually through p21 which has been shown to have enhanced expression in response to sphingosine kinase 2, one of the enzymes that mediate the conversion of sphingosine to sphingosine-1-phosphate.

Several studies associating chemotherapy with different drugs that attempt to modify sphingosine and ceramides metabolism have been published with some remarkable results, although never complete responses. We hypothesize that the incomplete responses may be due to an incomplete blockade of the conversion of ceramides and sphingosine towards their phosphorylated metabolites, sphingosine-1-phosphate and ceramide-1-phospate respectively.

Previous work has focused on single agents to enhance chemotherapy. In this work we are interested in studying the combination of different modifiers in the metabolism of ceramides/sphingosine with doxorubicin in order to achieve a total metabolic blockade in an effort to elicit a complete clinical response for prostate cancer.

Citation Format: Gonzalo Torga, Steven Mooney, Jelani C. Zarif, Kenneth J. Pienta. Induction of apoptosis in prostate cancer cells by altering cell metabolism. [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 2939. doi:10.1158/1538-7445.AM2015-2939
Abstract 2951: Evaluation of methylation biomarkers for colon cancer using normal tissues
Authors: Sapienza Carmen , Truongcao May M. , Ghosh Jayashri
Published: August 2015

We have identified DNA methylation biomarkers that discriminate patients with colon cancer from patients without colon cancer using array-based profiling methods. Most DNA-based biomarkers for colon cancer rely on the detection of cancer cell-specific or cancer cell-prevalent mutations or DNA methylation changes in small numbers of tumor cells or small amounts of tumor cell-free DNA that are present in stool or lavage samples. Our hypothesis is that an individual's cancer-predisposing exposure history is recorded in normal tissues as “field cancerization”-related DNA methylation changes and that these changes will be present in normal colon, as well as other normal tissues, including peripheral blood. Consistent with the notion of changes based on “individual exposure history”, the bulk of the candidate biomarkers identified are genes involved in carbohydrate and lipid metabolism, as expected from epidemiological associations between colon cancer and “western” diets. We have now validated that our candidate methylation biomarkers are effective at discriminating cancer patients from controls using normal colon tissue from an independent population, and irrespective of whether the patients have left-side or right-side cancers. We have also found that a significant fraction of our candidate biomarkers also discriminate cancer patients from controls, using peripheral blood DNA analyzed by bisulfite pyrosequencing.

Citation Format: Carmen Sapienza, May M. Truongcao, Jayashri Ghosh. Evaluation of methylation biomarkers for colon cancer using normal tissues. [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 2951. doi:10.1158/1538-7445.AM2015-2951
Abstract 2960: DNA promoter hypermethylation of genes as potential diagnostic and prognostic biomarkers for ovarian cancer
Authors: Valle Blanca L. , Kuhn Elisabetta , Sidransky David , Guerrero-Preston Rafael
Published: August 2015

Till recently, epithelial ovarian cancers were thought to arise from the ovarian surface epithelial cells. However, recent studies suggest that the majority of high grade serous carcinomas (HGSCs) arise from lesions in the fallopian tubes. DNA promoter hypermethylation of certain genes is often an early event in tumorigenesis, and it can be detected in blood and other bodily fluids, making it a feasible biomarker strategy for early detection of tumors. Therefore, we sought to determine the methylation profile of HGSCs as compared to fallopian tube epithelium, using the Infinium HumanMethylation 450 Array. We compared the methylation in 12 HGSC tissue samples to 15 fallopian tube epithelium samples. In addition, we compared the methylation profile among long-term survivors (more than 5 years) and short-term survivors (2-3 years) of HGSCs. Our results identified the promoter regions of HIST1H2BB, MAGI2, and EPSTI1 to be differentially methylated when comparing HGSC with normal fallopian tube samples. Furthermore, these genes were differentially methylated in HGSC patients with long-term survival when compared to patients with short-term survival. Quantitative methylation specific PCR analysis confirmed our results of differential methylation among short-term and long-term survivors, and show that these genes are also methylated in ovarian cancer cell lines. Taken together, we have identified genes that could have potential as diagnostic and prognostic biomarkers. Our findings could lead to the development of a biomarker panel for the diagnosis and/or prognosis of ovarian cancer.

Citation Format: Blanca L. Valle, Elisabetta Kuhn, David Sidransky, Rafael Guerrero-Preston. DNA promoter hypermethylation of genes as potential diagnostic and prognostic biomarkers for ovarian 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 2960. doi:10.1158/1538-7445.AM2015-2960
Abstract 2964: Histology-specific patterns of DNA methylation in Lynch-associated and sporadic ovarian cancer
Authors: Niskakoski Anni , Kaur Sippy , Staff Synnove , Renkonen-Sinisalo Laura , Lassus Heini , Järvinen Heikki J. , Mecklin Jukka-Pekka , Bützow Ralf , Peltomäki Päivi
Published: August 2015

Epithelial ovarian cancer is a heterogeneous group of cancers, and molecular tools are urgently needed for a better understanding and targeted management of this often lethal disease. Since epigenetic methods can offer new tools for the management of ovarian cancer, our aim was to investigate epigenetic mechanisms in ovarian tumorigenesis representing different histological types. Expression profiling of ovarian and endometrial cancer cell lines treated with demethylating agents as well as literature were used to select gene candidates for epigenetic regulation. A methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) assay was constructed for thirteen genes to study methylation in 104 (85 sporadic and 19 Lynch syndrome-associated) ovarian carcinomas.

Increased methylation (hypermethylation) was characteristic of ovarian cancer tissues relative to the corresponding normal tissues and hypermethylation was consistently more prominent in non-serous than serous tumors. The highest frequencies of hypermethylation were detected in Lynch-associated clear cell ovarian carcinomas. An interesting finding among endometrioid ovarian carcinomas was a significant association of lower levels of methylation in HOXA9, RSK4 and SPARC with higher tumor grade; thus, the methylation patterns of high-grade endometrioid ovarian carcinomas resembled epigenetic characteristics of high-grade serous tumors. Overall, non-serous ovarian tumors of Lynch and sporadic origin (as opposed to serous tumors) showed frequent epigenetic inactivation in RSK4, SPARC, PROM1, HOXA10, HOXA9, WT1-AS, SFRP2, SFRP5, OPCML, and MIR34B.

Our findings provide important new information regarding some critical genes affected by epigenetic dysregulation in ovarian tumorigenesis. The results will be utilized in future experiments aiming to define the genetic and epigenetic origins of ovarian carcinomas of different types.

Citation Format: Anni Niskakoski, Sippy Kaur, Synnove Staff, Laura Renkonen-Sinisalo, Heini Lassus, Heikki J. Järvinen, Jukka-Pekka Mecklin, Ralf Bützow, Päivi Peltomäki. Histology-specific patterns of DNA methylation in Lynch-associated and sporadic ovarian 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 2964. doi:10.1158/1538-7445.AM2015-2964
Abstract 2965: Identification of SMARCA4/BRG1 mutation types in NSCLC cell lines and tumors
Authors: Zhang Wei , Yao Yibing , Zhou Yunyun , Ma Xiaotu , Yan Jingsheng , Wang Tao , Girard Luc , Minna John , Xiao Guanghua , Xie Yang , Gazdar Adi
Published: August 2015

Purpose: Identification of SMARCA4/BRG1 mutation types in NSCLC cell lines and tumors. Background: The SMARCA4 gene encodes the major catalytic subunit of the SWI/SNF chromatin remodeling complex and is necessary for the transcriptional regulation of multiple cellular pathways. SMARCA4 is frequently mutated in lung cancer cell lines and in lung cancers. Methods: Sixty four NSCLC cell lines were analyzed. The Cancer Genome Atlas (TCGA) data were examined. SMARCA4 mutations were identified by NextGen and/or Sanger sequencing using genomic DNA or cDNA. Gene expression profiles and global methylation was determined by Illumina BeadChips. BRG1 protein was detected by immunoblotting. Results: SMARCA4 abnormalities were divided into Type1 (loss of full length protein, usually due to deletions, non-sense mutations or splicing site mutations) and Type 2 (homozygous or heterozygous missense mutations with protein present). Sequencing often failed to detect large deletions. Loss of SMARCA4/BRG1 resulted in profound downstream effects on the transcriptome and methylome, while existence of BRG1 with mutations has much less effects. Analysis using most significantly regulated transcripts can distinguish SMARCA4 type 1 abnormality from WT group, and indicate that type 2 abnormality effects were heterogeneous. SMARCA4 regulated transcripts are involved in many important cellular functions such as cell movement, death and proliferation and participate in many cytokines and hormone/nuclear receptors-mediated pathways. The expressions of transcription factors FOXA2 and NKX2-1 were decreased, while two groups of cancer testis antigens (CTAs), PRAME and MAGEA family were elevated in NSCLC cell lines and tumors with SMARCA4 mutations/low expression. Furthermore, FOXA2 and NKX2-1 were downregulated in an inducible SMARCA4 knock- down immortalized human lung epithelial cell line. Conclusions: SMARCA4 mutations can be divided into two types having varying downstream effects.

Citation Format: Wei Zhang, Yibing Yao, Yunyun Zhou, Xiaotu Ma, Jingsheng Yan, Tao Wang, Luc Girard, John Minna, Guanghua Xiao, Yang Xie, Adi Gazdar. Identification of SMARCA4/BRG1 mutation types in NSCLC cell lines and tumors. [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 2965. doi:10.1158/1538-7445.AM2015-2965
Abstract 2966A: A comprehensive investigation of insertional variations of human endogenous retrovirus elements in tumor tissues
Authors: Kahyo Tomoaki , Yamada Hidetaka , Tao Hong , Inoue Yusuke , Kurabe Nobuya , Sugimura Haruhiko
Published: August 2015

Human endogenous retrovirus (HERV) is a member of LTR-retrotransposon family. Retroviral invasions are thought to have occurred in the germ cell lines of human or human ancestors, and the fixed retroviral elements are recognized as HERV. A complete HERV sequence contains two long terminal repeats (LTRs) located at both ends. Because intact LTRs possess the highly conserved transcriptional promoter- and enhancer-sequences, to investigate insertional variations of HERV is a key process for understanding the etiology of human genetic diseases that remain unclear with the analyses targeting single nucleotide variations. However, genome-wide investigation of repetitive sequences including HERV is methodologically difficult, and comprehensive understanding of insertional variations of HERV, including a somatic retrotransposition of HERV, remains poor. In the previous study, we have identified two novel insertional polymorphisms of solo LTRs using the inverse PCR and cloning methods, and one of them was involved with the susceptibility to lung adenocarcinoma. Here, we detected multiple novel LTR loci in the human cancer tissues by developing the high-throughput sequencing method combined with inverse PCR. In this system, to preferentially detect insertional variations, primer sequences were designed based on the conserved region of the LTRs which have an identical sequence to the mate within the same HML-2 proviruse, because almost of known HERV insertional polymorphisms are found in HML-2, which is thought to be the most recently endogenized element of HERV, and the presence of an identical LTR sequence at both ends is necessary for the retrotransposition of exogenous retrovirus. The sequence reads generated from the high-throughput sequencer were trimmed, and the fragments consistent with the inverse PCR process were selected. Following the mapping to the reference genome, the sites not corresponding to known LTR loci were sorted out and subjected to the filtration to exclude the artificial fragments. As the result, some candidates of novel LTR loci were detected, and several of them were verified to be actually present both in tumor and non-tumor genomes using the Sanger method, suggesting they are insertional polymorphisms. By using this detection system, we are now challenging to investigate a novel LTR site specifically detected in tumor genome.

Citation Format: Tomoaki Kahyo, Hidetaka Yamada, Hong Tao, Yusuke Inoue, Nobuya Kurabe, Haruhiko Sugimura. A comprehensive investigation of insertional variations of human endogenous retrovirus elements in tumor tissues. [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 2966A. doi:10.1158/1538-7445.AM2015-2966A
Abstract 2984: Heterogeneous mechanisms of acquired resistance in high grade serous ovarian cancer
Authors: Bowtell David D L
Published: August 2015

In contrast to other solid cancers, overall survival for patients with high-grade serous ovarian cancer (HGSC) is little changed over the last 30 years and it has been difficult to advance beyond platinum-based combination chemotherapy. As HGSC are driven by genomic copy number change rather than recurrent point mutation, we undertook whole genome sequence (WGS) analysis of a large HGSC cohort in order to survey structural variation at high resolution. Utilizing 114 tumours from 92 patients, we performed transcriptome, methylation, and miRNA expression analyses to support the WGS data, and compared resistant, refractory, and sensitive primary disease. We evaluated tumour and normal DNA samples from patients with primary refractory, primary resistant or primary sensitive disease to better understand the drivers of these clinical phenotypes. We also characterized paired pre-treatment chemosensitive and post-resistance samples, and end-stage HGSC obtained from patients who underwent a research autopsy. We found that gene breakage involving tumour suppressors such as NF1 and RB1 is a common form of inactivation in HGSC and in other circumstances contributes to acquired chemotherapy resistance in some patients. We found evidence of a chemotherapy footprint in the genome of recurrent tumour samples. We observed a striking degree of diversity of other mechanisms of acquired resistance, including multiple independent germline BRCA1 or BRCA2 reversion events in individual patients, loss of BRCA1 promoter methylation, a shift in molecular subtype to a desmoplastic phenotype, and a recurrent promoter fusion associated with overexpression of a driver of drug resistance, validated in an independent dataset. Collectively our findings underscore the plasticity of the HGSC genome and indicate that pre-empting resistance by modifying current first line therapy or countering it when it emerges will require a diversity of approaches.

Citation Format: David D L Bowtell. Heterogeneous mechanisms of acquired resistance in high grade serous ovarian 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 2984. doi:10.1158/1538-7445.AM2015-2984