bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract LB-131: Mieap, a p53-inducible protein, controls mitochondrial quality by repairing or eliminating unhealthy mitochondria.
Authors: Nakamura Yasuyuki , Kamino Hiroki , Sano Hitoya , Arakawa Hirofumi
Published: August 2014

The accumulation of unhealthy mitochondria results in mitochondrial dysfunction, which has been implicated in aging, cancer, and a variety of degenerative diseases. However, the mechanism by which mitochondrial quality is regulated remains unclear. Here, we show that Mieap, a novel p53-inducible protein, plays a critical role in mitochondrial quality control. Mieap expression is directly regulated by p53 and is frequently lost in human cancer as result of DNA methylation. Mieap dramatically induces the accumulation of lysosomal proteins within mitochondria and mitochondrial acidic condition without destroying the mitochondrial structure (designated MALM, for Mieap-induced accumulation of lysosome-like organelles within mitochondria) in response to mitochondrial damage. MALM is involved in the degradation of oxidized mitochondrial proteins, leading to increased ATP synthesis and decreased reactive oxygen species generation. However, when MALM is inhibited, Mieap induces vacuole-like structures (designated as MIV for Mieap-induced vacuole), which engulf and degrade the unhealthy mitochondria by accumulating lysosomes. The inactivation of p53 severely impairs both MALM and MIV generation. These results suggest that Mieap plays a pivotal role in mitochondrial quality control by repairing or eliminating unhealthy mitochondria via MALM or MIV generation, respectively. Cancer cells might accumulate unhealthy mitochondria due to p53 mutations and/or Mieap methylation, representing a potential cause of the Warburg effect.

Citation Format: Yasuyuki Nakamura, Hiroki Kamino, Hitoya Sano, Hirofumi Arakawa. Mieap, a p53-inducible protein, controls mitochondrial quality by repairing or eliminating unhealthy mitochondria. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-131. doi:10.1158/1538-7445.AM2013-LB-131
Abstract LB-132: Frequent inactivation of the p53/Mieap/BNIP3 mitochondrial quality control pathway in gastric cancer.
Authors: Sano Hitoya , Kamino Hiroki , Nakamura Yasuyuki , Yoshida Masaki , Murai Ryuya , Saito Yuri , Futamura Manabu , Yoshida Kazuhiro , Arakawa Hirofumi
Published: August 2014

Recently, we discovered a novel mechanism for mitochondrial quality control (MQC), in which Mieap, a p53-inducible protein, controls MQC by repairing or eliminating unhealthy mitochondria via MALM (Mieap-induced Accumulation of Lysosome-like organelles within Mitochondria) or MIV (Mieap-Induced Vacuole) generation, respectively (1, 2). We also reported that two mitochondrial outer membrane proteins, BNIP3 and NIX, are essential mediators of the MALM (2, 3). To examine the role of Mieap-regulated MQC pathway in tumorigenesis, we analyzed the status of p53, Mieap, BNIP3, and NIX in 50 cases of primary gastric cancer. Of the 50 patients, Mieap and BNIP3 promoter methylation was observed in 2 (4%) and 29 (58%) patients, respectively. A p53 mutation was detected in 2 (10%) of the 20 patients with either Mieap or BNIP3 promoter methylation whereas it was found in 3 (15.8%) of the 19 patients with neither Mieap nor BNIP3 promoter methylation, implying that the p53/Mieap/BNIP3 MQC pathway is inactivated in at least 70% of gastric cancer cases. In a colorectal cancer cell line, hypoxia induced MALM. Knockdown of p53, Mieap, or BNIP3 in the cell line severely inhibited hypoxia-induced MALM, leading to the accumulation of unhealthy mitochondria and increased mitochondrial reactive oxygen species (mtROS) generation. Furthermore, the mtROS dramatically enhanced cancer migration and invasion in hypoxic conditions. These results suggest that the p53/Mieap/BNIP3 MQC pathway plays a tumor-suppressive role in gastric cancer.

1. Miyamoto Y et al. PLoS ONE 6: e16054, 2011

2. Kitamura N et al. PLoS ONE 6: e16060, 2011

3. Nakamura Y et al. PLoS ONE 7: e30767, 2012

Citation Format: Hitoya Sano, Hiroki Kamino, Yasuyuki Nakamura, Masaki Yoshida, Ryuya Murai, Yuri Saito, Manabu Futamura, Kazuhiro Yoshida, Hirofumi Arakawa. Frequent inactivation of the p53/Mieap/BNIP3 mitochondrial quality control pathway in gastric cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-132. doi:10.1158/1538-7445.AM2013-LB-132
Abstract LB-135: Stanniocalcin 2 attenuates tumor cell proliferation but suppresses apoptosis in nutrient-deprived conditions.
Authors: Qie Shuo , Tian Lifeng , Wang Chenguang , Sang Nianli
Published: August 2014

High levels of stanniocalcin2 (STC2), a member of the STC secreted glycoprotein family, correlates with tumor progression and poor prognosis. It has been reported that STC2 is over-expressed in response to various stresses, including hypoxia, endoplasmic reticulum stress, oxidative stress and irradiation. Glutamine (Gln) and glucose (Glc) are important nutrients for tumor cells, playing important roles as nitrogen and carbon sources to meet the bioenergetic, biosynthetic and reductive needs. Defective blood supply in solid tumors may result in nutrient insufficiency, including Gln and Glc insufficiency. It remains unknown how tumor cells respond to Gln- and Glc- insufficient microenvironment and regulate their viability and proliferation. Using gene profiling analysis with microarrays, we have identified STC2 as one of the most up-regulated genes in response to either Gln- or Glc- deprivation. We confirm that Gln-deprivation stimulates STC2 expression at both mRNA and protein levels in various human tumor cells by quantitative reverse transcription-real-time PCR and Western blot, respectively. Furthermore, we find that Gln-insufficiency activates both nuclear factor-κB (NF-κB) and ATF4 signaling pathways, which synergistically up-regulates STC2. Finally, we demonstrate that up-regulation of STC2 attenuates tumor cell proliferation but reduces apoptosis in Gln-insufficient conditions. These findings suggest a novel model that STC2 reprograms the priority of tumor cells from rapid proliferation to survival under stress conditions, indicating that STC2 may be a novel target for cancer therapy.

Citation Format: Shuo Qie, Lifeng Tian, Chenguang Wang, Nianli Sang. Stanniocalcin 2 attenuates tumor cell proliferation but suppresses apoptosis in nutrient-deprived conditions. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-135. doi:10.1158/1538-7445.AM2013-LB-135
Abstract LB-154: COX-2 as a mediator of oncogenic PKCε in prostate cancer.
Authors: Garg Rachana , Lal Priti , Blando Jorge , Benavides Fernando J. , Feldman Michael D. , Smyth Emer M. , Kazanietz Marcelo G.
Published: August 2014

Protein kinase C epsilon (PKCε), a member of the PKC family of phorbol ester/diacylglycerol receptors, is up-regulated in many human cancers, including prostate cancer. We recently demonstrated that PKCε is an essential mediator of NF-κB activation in prostate cancer (Garg et al., JBC, 287 (44), 37570–37582, 2012). Cyclooxygenase-2 (COX-2), a well-known NF-κB regulated gene, has been reported to be up-regulated in a number of human cancers, including metastatic prostate cancer. As PKCε plays an important role in prostate cancer cell survival and cooperates with other oncogenic insults, herein we aim to determine if PKCε regulates COX-2 activation during prostate tumorigenesis. PKCε RNAi depletion diminishes TNFα- or LPS-induced COX-2 mRNA expression in LNCaP prostate cancer cells and constitutive COX-2 levels from PC3 cells. Conversely, PKCε overexpression by adenoviral means potentiates TNFα or LPS-induced COX-2 expression in LNCaP cells. Notably, transgenic overexpression of PKCε in the mouse prostate causes preneoplastic lesions with elevated COX-2 levels. Interestingly, when we intercrossed the prostate-specific PKCε transgenic mice with mice haploinsufficient for Pten, a common genetic alteration in human prostate cancer, the resulting compound mutant mice (PB-PKCε;Pten+/− mice) developed fully invasive adenocarcinoma with NF-κB hyperactivation and high COX-2 levels. Likewise, stable overexpression of PKCε in mouse prostate epithelial cell lines that are either heterozygous (P8) or homozygous (CaP8) for Pten deletion, led to significant enhancements in cell proliferation, motility and invasiveness as well as in LPS-induced COX-2 mRNA expression compared to the respective control cells, and this effect is more pronounced in CaP8 cells. Studies using human prostate tumors revealed a co-existence of PKCε overexpression, NF-κB hyperactivation, and COX-2 up-regulation. Lastly, treatment of PKCε overexpressing P8 or CaP8 cells with the selective COX-2 inhibitor NS398 caused a pronounced growth inhibition. Overall, our study identified COX-2 as a PKCε-regulated gene. Our results suggest that COX-2 as a potential mediator of PKCε oncogenesis in prostate cancer, particularly in the context of Pten loss.

Citation Format: Rachana Garg, Priti Lal, Jorge Blando, Fernando J. Benavides, Michael D. Feldman, Emer M. Smyth, Marcelo G. Kazanietz. COX-2 as a mediator of oncogenic PKCε in prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-154. doi:10.1158/1538-7445.AM2013-LB-154
Abstract LB-187: Dietary energy balance modulation of Kras- and Ink4a/Arf+/-driven pancreatic cancer: the role of insulin-like growth factor-1.
Authors: Lashinger Laura M. , Harrison Lauren M. , Rasmussen Audrey J. , Logsdon Craig D. , Fischer Susan M. , McArthur Mark J. , Hursting Stephen D.
Published: August 2014

New molecular targets and intervention strategies for breaking the obesity-pancreatic cancer link are urgently needed. Using relevant murine spontaneous and orthotopically transplanted models of pancreatic cancer, we tested the hypothesis that dietary energy balance modulation impacts pancreatic cancer development and progression through an insulin-like growth factor (IGF) 1—dependent mechanism. In LSL-KrasG12D/Pdx-1-Cre/Ink4a/Arflox/+ mice, calorie restriction, versus overweight- or obesity-inducing diet regimens, decreased serum IGF-1, tumoral Akt/mammalian target of rapamycin (mTOR) signaling, pancreatic desmoplasia, and progression to pancreatic ductal adenocarcinoma (PDAC); and increased pancreatic tumor-free survival by 50%. Serum IGF-1, Akt/mTOR signaling, and orthotopically transplanted PDAC growth were decreased in liver-specific IGF-1—deficient mice (versus wild-type mice), and rescued with IGF-1 infusion. Thus, dietary energy balance modulation impacts spontaneous pancreatic tumorigenesis induced by mutant Kras and Ink4a/Arf deficiency, the most common genetic alterations in human pancreatic cancer. Furthermore, IGF-1 and components of its downstream signaling pathway are promising mechanistic targets for breaking the obesity-pancreatic cancer link.

Citation Format: Laura M. Lashinger, Lauren M. Harrison, Audrey J. Rasmussen, Craig D. Logsdon, Susan M. Fischer, Mark J. McArthur, Stephen D. Hursting. Dietary energy balance modulation of Kras- and Ink4a/Arf+/-driven pancreatic cancer: the role of insulin-like growth factor-1. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-187. doi:10.1158/1538-7445.AM2013-LB-187
Abstract LB-189: BIRC5 (Survivin) is a prognostic biomarker and potential drug target for patients with malignant peripheral nerve sheath tumors.
Authors: Kolberg Matthias , Høland Maren , Ågesen Trude H. , Skotheim Rolf I. , Bjerkehagen Bodil , Hall Kirsten S. , Mertens Fredrik , Smeland Sigbjørn , Lev Dina C. , Davidson Ben , Lote Ragnhild A.
Published: August 2014

Malignant peripheral nerve sheath tumor (MPNST) is a rare soft tissue cancer with high mortality, and there are currently few therapeutic options beyond surgery. We have performed a transcriptome study of 30 MPNSTs and 8 neurofibromas and used a tissue microarray (TMA) with cores from 63 MPNSTs to identify candidate genes and proteins for targeted therapy. The anti-apoptotic gene BIRC5 was one of the most significantly upregulated genes in MPNST vs neurofibroma. This gene is located on the long arm of chr 17, and we have previously shown common gains of 17q sequences and pinpointed BIRC5 as a potential target in MPNSTs. Recently BIRC5 was also identified as a potential drug target. Here, we show that MPNST patients with above median BIRC5 mRNA expression levels had significantly worse 5-year disease-specific survival (DSS: 26%) than patients with below median mRNA levels (DSS: 87%) (P=.0003). Immunohistochemical analyses showed that increased protein expression is also associated with a worse disease outcome (P=.02). We recently performed a meta-analysis on survival for NF1 associated MPNST and sporadic MPNST based on 1800 patients which suggest no difference between these groups. Our data suggest that MPNST patients who present tumors with high expression of BIRC5 might benefit from targeted treatment directed against BIRC5.

Citation Format: Matthias Kolberg, Maren Høland, Trude H. Ågesen, Rolf I. Skotheim, Bodil Bjerkehagen, Kirsten S. Hall, Fredrik Mertens, Sigbjørn Smeland, Dina C. Lev, Ben Davidson, Ragnhild A. Lote. BIRC5 (Survivin) is a prognostic biomarker and potential drug target for patients with malignant peripheral nerve sheath tumors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-189. doi:10.1158/1538-7445.AM2013-LB-189
Abstract LB-212: Mcl-1 and FBW7 control a dominant survival pathway underlying HDAC and Bcl-2 inhibitor synergy in squamous cell carcinoma.
Authors: He Lei , Torres-Lockhart Kristine , Forster Nicole , Ramakrishnan Saranya , Greninger Patricia , Garnett Mathew J. , McDermott Ultan , Rothenberg S. Michael , Benes Cyril , Ellisen Leif
Published: August 2014

Effective targeted therapeutics for squamous cell carcinoma (SCC) are lacking. Here we uncover Mcl-1 as a dominant and tissue-specific survival factor in SCC, providing a roadmap for a new therapeutic approach. Treatment with the HDAC inhibitor vorinostat regulates Bcl-2 family member expression to disable the Mcl-1 axis and thereby induce apoptosis in SCC cells. Although Mcl-1 dominance renders SCC cells resistant to the BH3 mimetic ABT-737, vorinostat primes them for sensitivity to ABT-737 by shuttling Bim from Mcl-1 to Bcl-2/Bcl-xl, resulting in dramatic synergy for this combination and sustained tumor regression in vivo. Moreover, somatic FBW7 mutation in SCC is associated with stabilized Mcl-1 and high Bim levels, resulting in a poor response to standard chemotherapy but a robust response to HDAC inhibitors and enhanced synergy with combination vorinostat/ABT-737. Collectively, our findings provide a biochemical rationale and predictive markers for the application of this therapeutic combination in SCC.

Citation Format: Lei He, Kristine Torres-Lockhart, Nicole Forster, Saranya Ramakrishnan, Patricia Greninger, Mathew J. Garnett, Ultan McDermott, S. Michael Rothenberg, Cyril Benes, Leif Ellisen. Mcl-1 and FBW7 control a dominant survival pathway underlying HDAC and Bcl-2 inhibitor synergy in squamous cell carcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-212. doi:10.1158/1538-7445.AM2013-LB-212
Abstract LB-217: A gene signature that predicts deficiency of homologous recombination DNA repair.
Authors: Peng Guang , Mills Gordon , Lin Shiaw-Yih
Published: August 2014

DNA repair pathways play a fundamental role to maintain genomic stability. Defects in specific DNA repair pathways predispose to cancer development, but also provide therapeutic opportunities: for example, poly-ADP ribose polymerase (PARP) inhibitors are synthetically lethal with cancer cells, which are defective in homologous recombination (HR)-mediated DNA repair, such as BRCA1/BRCA2-deficient tumors. However, recent clinical trials of PARP inhibitors have shown rather disappointing results, particularly in the treatment of triple-negative breast cancer (TNBC), which has a molecular phenotype similar to that of BRCA-deficient breast cancer. As a targeted therapy, the clinical success of PARP inhibitors is dependent on identifying cancer cells with HR repair deficiency. Thus the observations of PARP inhibitors from clinical trials raise a key question: Can we identify a molecular signature of HR repair deficiency in cancer cells?

To answer this question, we utilized the gene expression profiling approach to measure the cellular transcriptional reprograming in HR-deficient cell lines. By analyzing the molecular changes of transcriptional landscape, we identified an HR-defect gene signature that predicted HR repair deficiency in cells, predicted clinical outcomes of multiple human cancers, and predicted sensitivity of human cancer cells to PARP inhibitors. HR repair deficiency leads to genomic instability and often promotes accumulation of additional mutations. Our gene signature analysis further revealed that combinatorial effects of co-existing genetic changes such as loss of both BRCA1 and PTEN may extensively rewire the HR repair network and confer resistance to PARP inhibitor treatment. Moreover, to combat PARP inhibitor resistance, we successfully used our HR-defect gene signature as a drug discovery tool and found that TTK, mTOR and PI3K inhibitors could induce HR repair deficiency and sensitize cancer cells to PARP inhibitor treatment. Collectively, our findings demonstrate that transcriptional signature can be used to define the functional status of the HR repair network in cells.

In summary, our study identifies a gene signature of HR repair deficiency, which provides a novel network view of the DNA repair process. In addition to using our gene signature as a prognostic marker for multiple cancers including breast, ovarian and lung cancer, our findings potentially have a significant impact on predicting responsiveness and overcoming resistance to targeted therapeutic regimens with DNA repair inhibitors such as PARP inhibitors.

Citation Format: Guang Peng, Gordon Mills, Shiaw-Yih Lin. A gene signature that predicts deficiency of homologous recombination DNA repair. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-217. doi:10.1158/1538-7445.AM2013-LB-217
Abstract LB-22: P53 genetic polymorphisms, interactions with lifestyle factors and lung cancer risk in a Chinese population.
Authors: Li Yanli , Chang Shen-Chih , Niu Rungui , Liu Li , Crabtree-Ide Christina R. , Zhao Baoxing , Shi Jianping , Han Xiaoyou , Li Jiawei , Su Jia , Cai Lin , Yu Shunzhang , Zhabg Zuo-Feng , Mu Lina
Published: August 2014

Background: A GWAS study suggested rs2078486 was a novel functional p53 SNP, but very few studies replicate this association. P53 rs1042522 is the most commonly studied SNP, but very few studies examined its potential interaction with environmental factors in relation to lung cancer risk. This study aims to examine associations between two p53 single-nucleotide polymorphisms (SNPs) (rs2078486, rs1042522), their potential interaction with environmental factors and risk of lung cancer.

Methods: A case-control study was conducted in Taiyuan, China. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs). Multiplicative and additive interactions between p53 SNPs and lifestyle factors were evaluated.

Results: Variant p53 rs2078486 SNP was significantly associated with elevated lung cancer risk among smokers (OR: 1.70, 95% CI: 1.08 - 2.67) and individuals with high indoor air pollution exposure (OR: 1.51, 95% CI: 1.00-2.30). Significant or borderline significant multiplicative and additive interactions were found between p53 rs2078486 polymorphism with smoking and indoor air pollution exposure. The variant genotype of p53 SNP rs1042522 significantly increased lung cancer risk in the total population (OR: 1.57, 95% CI: 1.11-2.21), but there was no evidence of heterogeneity among individuals with different lifestyle factors.

Conclusion: This study confirmed that p53 rs2078486 SNP is potentially a novel functional p53 SNP that may affect lung cancer risk. Our study also suggested potential synergetic effects of p53 rs2078486 SNP with smoking and indoor air pollution exposure on lung cancer risk.

Citation Format: Yanli Li, Shen-Chih Chang, Rungui Niu, Li Liu, Christina R. Crabtree-Ide, Baoxing Zhao, Jianping Shi, Xiaoyou Han, Jiawei Li, Jia Su, Lin Cai, Shunzhang Yu, Zuo-Feng Zhabg, Lina Mu. P53 genetic polymorphisms, interactions with lifestyle factors and lung cancer risk in a Chinese population. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-22. doi:10.1158/1538-7445.AM2013-LB-22
Abstract LB-220: The Integrinβ1/Src/Akt-driven bypass signaling pathway contributes to Erlotinib resistance in lung cancer.
Authors: Ono Mayumi , Kanda Rina , Watari Kosuke , Kawahara Akihiko , Kage Masayoshi , Uramoto Hidetaka , Kuwano Michihiko
Published: August 2014

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) such as gefitinib and erlotinib have improved therapeutic efficacies on non-small cell lung cancer (NSCLC) harboring activating EGFR mutations. However, appearance of drug resistant mutation limits patients' outcome. A secondary T790M mutation and MET amplification are two major mechanisms of acquired EGFR-TKI resistance.

To develop novel therapeutics to overcome drug resistant tumors, we should further understand other mechanisms at molecular basis of intrinsic importance.

We established erlotinib or gefitinib resistant cell lines from PC9 cells that harbor an activating EGFR deletion mutation by chronic exposure to these TKIs. We have previously identified that loss of PTEN or loss of activated EGFR gene allele is responsible for acquired resistance (Cancer Res., 2010; Nat Med., 2011; PLoS ONE, 2012; Cancer Sci., 2013). In our present study, one erlotinib-resistant subline from PC9 cells revealed following interesting characteristics;

[1] The increased expression of integrins β1, α2, and α5 was observed, along with enhanced adhesion and migratory activity in the resistant sublines.

[2] The increased expression and activation of Src was also observed.

[3] Interestingly, integrinβ1 knockdown markedly restored sensitivity to erlotinib and reduced the activation of Src and Akt upon treatment with erlotinib.

[4] Furthermore, Src knockdown suppressed Akt phosphorylation and cell growth, and this inhibitory effect was further augmented by erlotinib.

[5] The expression of integrins β1 and α5 was also observed in a refractory tumor sample from a lung cancer patient treated with erlotinib. Together, we will present our novel concept that integrinβ1/Src/Akt pathway represents a novel a bypass effector pathway for the acquisition of resistance to EGFR-TKIs.

Citation Format: Mayumi Ono, Rina Kanda, Kosuke Watari, Akihiko Kawahara, Masayoshi Kage, Hidetaka Uramoto, Michihiko Kuwano. The Integrinβ1/Src/Akt-driven bypass signaling pathway contributes to Erlotinib resistance in lung cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-220. doi:10.1158/1538-7445.AM2013-LB-220
Abstract LB-225: Resistance to paclitaxel in triple negative breast cancer cells is associated with ABCB1 overexpression and gene amplification, and can be reversed by anti-EGFR targeting.
Authors: Ahmadzadeh Elaheh , Przybytkowski Ewa , Aguilar-Mahecha Adriana , Basik Mark
Published: August 2014

Background: Due to the absence of expression of estrogen, progesterone and HER2 receptors, triple negative breast cancer (TNBC) patients do not benefit from targeted therapies. Therefore, chemotherapy remains the only treatment of choice for patients with TNBC. Despite initial clinical responses to chemotherapy, the majority of TNBC patients acquire resistance and develop progressive disease. There is little data about mechanisms of resistance to chemotherapy in TNBCs.

Methods: We investigated the molecular mechanisms of acquired resistance to paclitaxel (PTX) in TNBCs. Four TNBC cell lines (BT20, SUM149, MA-MB-231 and MDA-MB-436) were cultured in the presence of increasing concentrations of paclitaxel until they acquired resistance. Gene expression and aCGH analysis were performed on all parental and resistant pairs.

Results: We found a novel amplification of the ABCB1 gene in BT20 and SUM149 resistant cell lines only. Gene expression analysis revealed significant up-regulation of expression of ABCB1 and EGFR ligands in SUM149 and BT20 resistant cells compared to parental cell lines. The functional activity of ABC transporters assessed using rhodamine 123 efflux assay demonstrated a marked increase in the efflux of rhodamine in SUM149-R and BT20-R which was reversed by verapamil. We treated resistant cells with two anti-EGFR drugs, lapatinib and neratinib, which are also known ABC transporter inhibitors, and found that both drugs inhibited rhodamine 123 efflux and restored sensitivity to PTX in these PTX-resistant TNBC cells.

Conclusion: This is the first report of ABCB1 gene amplification in paclitaxel resistant triple negative breast cancer cells. Our results suggest that ABCB1 gene amplification and EGFR ligand over-expression plays a critical role in the development of PTX resistance in TNBC cells, and that this resistance can be targeted by therapy with anti-EGFR agents. Thus, ABCB1 gene amplification and EGFR ligand expression may be novel predictive biomarkers for both chemotherapy and anti-EGFR therapy in TNBCs.

Citation Format: Elaheh Ahmadzadeh, Ewa Przybytkowski, Adriana Aguilar-Mahecha, Mark Basik. Resistance to paclitaxel in triple negative breast cancer cells is associated with ABCB1 overexpression and gene amplification, and can be reversed by anti-EGFR targeting. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-225. doi:10.1158/1538-7445.AM2013-LB-225
Abstract LB-234: A comparative genomic approach for identifying synthetic lethal interactions in human cancer.
Authors: Asiedu Michael K. , Deshpande Raamesh , Klebig Mitchell , Sutor Shari , Kuzmin Elena , Piotrowski Jeff , Shin Seung Ho , Costanzo Michael , Boone Charles , Wigle Dennis A. , Myers Chad L
Published: August 2014

Synthetic lethal interactions enable a novel approach for discovering specific genetic vulnerabilities in cancer cells that can be exploited for the development of therapeutics. This concept has recently been exploited in the development of PARP inhibitors as novel chemotherapeutics for breast cancer. While PARP is not essential in normal cells, BRCA mutant cells are dependent on it for their survival. This led to the successful treatment of BRCA mutant tumors of the breast, ovary, and prostate with the oral PARP inhibitor, olaparib. Therapeutic strategies based on such synthetic-lethal (SL) interactions can enable drug targeting of cancer-specific alterations for otherwise undruggable tumor suppressors. Large-scale analyses of genetic interaction networks in model organisms like yeast suggest that disease-specific networks should not only give rise to destructive phenotypes (e.g. uncontrolled cell growth), but will also present unique vulnerabilities that can be exploited for novel therapies. Despite successes in model organisms such as yeast, discovering synthetic lethal interactions on a large scale in human cells remains a significant challenge. We have used a combination of computational and experimental approach whereby yeast interactions between human orthologs are filtered by cancer association and prioritized by genomic features, and candidates from the prioritized list are then validated in human cell lines using an RNA interference approach. As a proof of principle, we utilized this approach to discover two previously unknown synthetic lethal/sick interactions, one between SMARCB1 (yeast SNF5) and PSMA4 (yeast PRE9), and another between ASPSCR1 (yeast UBX4) and PSMC2 (yeast RPT1) based on shRNA double knock-down in normal human fibroblast cells. These interactions suggest potentially new therapeutic targets for SMARCB1 and ASPSCR1 mutated cancers, and more broadly, illustrate the potential of this cross-species approach.

Citation Format: Michael K. Asiedu, Raamesh Deshpande, Mitchell Klebig, Shari Sutor, Elena Kuzmin, Jeff Piotrowski, Seung Ho Shin, Michael Costanzo, Charles Boone, Dennis A. Wigle, Chad L Myers. A comparative genomic approach for identifying synthetic lethal interactions in human cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-234. doi:10.1158/1538-7445.AM2013-LB-234
Abstract LB-240: A novel approach to detecting RNA expression in living breast cancer cells.
Authors: Weldon Don , Su Kevin , Ko Alex , Johnston Grace , Hsu Matthew , Armstrong Lucas
Published: August 2014

When studying the complexities of cancer biomarkers, the ability to monitor gene expression within live cells that have become cancerous provides better insight than examining fixed or lysed tissues. However, monitoring RNA within intact cells can prove to be challenging with current techniques, which involve complex RNA isolation procedures that compromise cell viability. Further, amplification methods can create false positives or erroneously inflate differences. Here we describe a probe-based detection method that allows for the detection of ErbB-2 and EGFR mRNA levels across live intact SK-BR-3 breast cancer cells without the need for transfection reagents. The detection methodology is based upon an oligonucleotide gold nanoparticle conjugate capable of detecting intracellular levels of mRNA and miRNA in living cells. The probes enter the cell by means of the cell's native endocytosis machinery. Upon binding to the complementary target RNA sequence, a fluorescent signal (flare) is released, which allows the cells to be detected on any fluorescence analysis platform. In contrast to traditional RNA detection methods, since our technique allows for detection within live cells without altering their gene expression, the same cells that were profiled for EGFR and ErbB-2 expression could be sorted based on their specific mRNA content and subsequently further studied. Stimulation or treatments could then be performed on the previously profiled cells and assessed using probes for additional RNA markers or more traditional techniques such as antibody staining, qRT-PCR, or Array profiling. For this purpose, we combined immunostaining for cell surface EGFR with fluorogenic nanoparticle-based detection of EGFR mRNA in 4 breast cancer cell lines known to range in EGFR expression levels, and observed significant correlation for the signals in two-color flow cytometry. Thus, detecting RNA expression levels in live cancer cells with the ability to utilize the same cells in downstream testing gives researchers the ability to perform experiments which were previously thought to be impossible.

Citation Format: Don Weldon, Kevin Su, Alex Ko, Grace Johnston, Matthew Hsu, Lucas Armstrong. A novel approach to detecting RNA expression in living breast cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-240. doi:10.1158/1538-7445.AM2013-LB-240
Abstract LB-241: Silencing of microRNA-31 prevents esophageal neoplasia in zinc deficient rats.
Authors: Taccioli Cristian , Chen Hongping , Garofalo Michela , Jiang Yubao , Di Leva Gianpiero , Alder Hansjuerg , Middleton Justin , Smalley Karl J. , Bottoni Arianna , Costinean Stefan , Farber John L. , Croce Carlo M. , Fong Louise Y Y
Published: August 2014

Dietary zinc deficiency (ZD) is implicated in the pathogenesis of human esophageal squamous cell carcinoma (ESCC). microRNA-31 (miR-31) is overexpressed in human ESCC. In the rat a ZD diet promotes esophageal carcinogenesis by inducing cellular proliferation and changes in the expression of microRNA and mRNA, including overexpression of miR-31 and cancer-related proinflammation genes. Here we report that treatment of ZD rats with locked nucleic acid (LNA)-modified inhibitor of miR-31 (LNA-antimiR) prevents the development of a precancerous esophageal phenotype. Weanling rats were fed ZD or zinc-sufficient (ZS) diet for 5 weeks. Simultaneously, ZD rats were administered intravenously (twice a week) LNA-antimiR, LNA-scramble miR-31 or the vehicle saline. ZS rats received saline. Compared to ZS rats, LNA-scramble miR-31-treated or saline-treated ZD rats overexpressed miR-31 and displayed a highly proliferative and inflammatory esophageal phenotype. Treatment of ZD rats with LNA-antimiR reduced miR-31 expression in esophageal epithelia and circulating blood by ~60% and reversed the ZD-induced esophageal pathology, as evidenced by a thinned esophageal epithelium with reduced cell proliferation by PCNA immunohistochemistry and increased apoptosis by caspase-3/7 activity. Transcriptome analyses of esophageal epithelia demonstrated derepression of target mRNAs with miR-31 seed sites. In particular, Stk40 (a negative regulator of NF-κ? signaling) was demonstrated to be a bona fide miR-31 target. Using in situ hybridization and immunohistochemistry, miR-31 overexpression in ZD esophageal sections correlated with downregulation of STK40 protein, as well as with upregulation of an NF-κ? p65 - RAGE-S100A9 inflammatory pathway that in turn, was normalized by miR-31 silencing. Thus, silencing miR-31 prevents esophageal neoplasia. Overexpression of miR-31 promotes ESCC initiation by enhancing inflammation via STK40 - NF-κ? signaling. The data indicate that miR-31 may be a promising therapeutic target for improved ESCC diagnosis and prevention. Funding: National Institutes of Health grants U01 CA152758 to CMC and R01CA118560 & R21CA152505 to LYYF.

Citation Format: Cristian Taccioli, Hongping Chen, Michela Garofalo, Yubao Jiang, Gianpiero Di Leva, Hansjuerg Alder, Justin Middleton, Karl J. Smalley, Arianna Bottoni, Stefan Costinean, John L. Farber, Carlo M. Croce, Louise Y Y Fong. Silencing of microRNA-31 prevents esophageal neoplasia in zinc deficient rats. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-241. doi:10.1158/1538-7445.AM2013-LB-241
Abstract LB-25: Exploration of genome-wide circulating microRNA in hepatocellular carcinoma (HCC) - dysregulation of miR-483-5p and miR-150 as diagnostic marker.
Authors: Shen Jing , Wang Antai , Wang Qiao , Gurvich Irina , Siegel Abby B. , Remotti Helen , Santella Regina M.
Published: August 2014

The incidence of hepatocellular carcinoma (HCC) has doubled over the past 20 years in the United States (US). HCC prognosis is poor if not diagnosed and treated at an early stage. MicroRNAs (miRNAs) are a class of small non-coding RNAs that control gene expression by inhibiting translation or inducing cleavage of target messenger RNAs (mRNAs). miRNAs can regulate diverse biological processes including DNA repair, apoptosis, cell proliferation, differentiation and immune function. Circulating miRNAs in cell-free plasma/serum samples have been consistently observed to have high stability and resistance to storage/handling, suggesting their potential use as diagnostic biomarkers. We conducted a two-phase epidemiological case-control study to test the hypothesis that genome-wide dysregulation of circulating miRNAs differentiate HCC cases from controls. A total of 69 HCC patients and 69 controls were recruited and matched on age, gender and ethnicity. Taqman low density arrays were used to examine genome-wide miRNA expression, and quantitative RT-PCR was used to validate promising candidates. Sixty-six miRNAs were found to be significantly over-expressed in plasma of HCC cases compared to controls after adjusting for false discovery rate (p<0.05). A volcano plot indicated that 7 miRNAs had over 2-fold case-control differences with p<0.01. Four significant miRNAs (miR-150, miR-30c, miR-483-5p and miR-520b) detectable in all samples with varied expression levels were further validated in an expanded case-control study. MiR-483-5p was statistically significantly over-expressed in HCC cases compared with controls (3.25 vs. 0.54, p<0.0001). MiR-150 was up-regulated in HCC, but the difference was not significant (5.66 vs. 5.29). The combination of plasma levels of miR-483-5p and miR-150 can significantly differentiate HCC cases from controls with an AUC of 0.850 (p<0.0001). The sensitivity and specificity were, respectively, 63.8% and 85.5%. These preliminary data indicated the importance of dysregulated circulating miRNAs in hepatocarcinogenesis, and suggesting the possibility of using miR-483-5p and miR-150 as diagnostic biomarkers. Large prospective studies are necessary to replicate the current findings, and evaluate the panel of circulating miRNAs in improving early diagnosis of HCC.

Citation Format: Jing Shen, Antai Wang, Qiao Wang, Irina Gurvich, Abby B. Siegel, Helen Remotti, Regina M. Santella. Exploration of genome-wide circulating microRNA in hepatocellular carcinoma (HCC) - dysregulation of miR-483-5p and miR-150 as diagnostic marker. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-25. doi:10.1158/1538-7445.AM2013-LB-25
Abstract LB-253: TRAPing telomerase activity using droplet digital PCR.
Authors: Shelton Dawne , Regan Jack , Karlin-Neumann George , Lin Jue , Blackburn Elizabeth
Published: August 2014

The aim of this work was to develop a more sensitive and high throughput assay for measuring telomerase activity. Telomeres are the protective structures at the ends of chromosomes consisting of 6 bp repeat sequences. In young cells, these regions can be as long as 15kb and act as caps which protect the DNA ends. These ends naturally degrade with each passing cell division, usually losing 25-200 base pairs per division. Once they are shortened below a critical length (estimated to be 200-300 bp) the cells arrest and become senescent, or “old”. Telomeres can be thought of as a cellular or mitotic clock. Once the clock has wound down, the cells either die or pass through crisis and become immortal.

One of the mechanisms of immortality is the activation of the enzyme, telomerase. Telomerase is the endogenous reverse transcriptase responsible for adding repeats to telomeres, rewinding the clock and enabling a cell to continuously divide. Abundant telomerase activity is found in fetal and adult stem cells, germ cells, and cancer. It is also present at much lower levels in non-stem cells, such as immune cells, but these levels can be difficult to measure reliably.

The telomerase repeat amplification protocol (TRAP) measures the presence of active telomerase by measuring the activity of the enzyme on a starting DNA template, which is then amplified by PCR. For samples with abundant telomerase activity, SYBR qPCR assays provide high throughput. However, the current most sensitive method of detection still uses radioactivity, laborious PAGE sequencing gels, and densitometry to quantify telomerase.

Here we explore using droplet digital™ PCR (ddPCR™) to provide absolute quantification of telomerase activity. This was achieved through single-molecule counting of telomerase-extended templates that were partitioned into droplets, amplified by PCR and detected by fluorescence droplet flow cytometry. Analysis of control samples suggests ddPCR is at least an order of magnitude more sensitive than TRAP radiography and is more amenable to higher throughput analysis. We extend throughput, sensitivity, and the range of biological samples that can be analyzed for telomerase activity.

Citation Format: Dawne Shelton, Jack Regan, George Karlin-Neumann, Jue Lin, Elizabeth Blackburn. TRAPing telomerase activity using droplet digital PCR. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-253. doi:10.1158/1538-7445.AM2013-LB-253
Abstract LB-254: XBP1-NFkappaB signaling promotes antiestrogen resistance in breast cancer animal model.
Authors: Hu Rong , Zwart Alan , Warri Anni , Clarke Robert
Published: August 2014

There are nearly 3 million breast cancer survivors in the United States, with more than 230,000 women being newly diagnosed with invasive breast cancer each year. Of total breast cancer patients, around 70 percent are estrogen receptor (ER) positive and often receive endocrine therapy. Endocrine resistance, either de novo or acquired, is a major hurdle for treating ER positive breast cancer patients. Unfolded protein response (UPR) is known to be activated and promote endocrine resistance in breast cancer cells. As an essential component of URP signaling, X-box binding protein 1 (XBP1) was shown up-regulated in endocrine resistant breast cancer. XBP1 was demonstrated as an important mediator for endocrine resistance in vitro cell culture model in our previous findings. In this study, the effect of XBP1 in endocrine resistance in animal model was examined. XBP1 contains two alternative splice variants: XBP1(S) and XBP1(U). In order to differentiate the role of each variant, we generated XBP1 mutant constructs that overexpress specifically only either the XBP1(S) or XBP1(U).

The XBP1 over-expressing human breast cancer cells have been injected into the mammary fat pad of female nude mice. The preliminary data shows that the over-expression of both XBP1 splice variants promotes tumor growth in vivo. More importantly, tumors with over-expressed XBP1 show less sensitivity to tamoxifen treatment. Our previous finding revealed that NFkappaB signaling is regulated by XBP1 and required for antiestrogen resistance in cultured cells. In the current study, we have treated XBP1-overexpressed breast tumor bearing animals with NFkappaB inhibitor Parthenolide, and find that it enhances tamoxifen sensitivity. In conclusion, our data demonstrate that XBP1-NFkappaB signaling plays an important role in antiestrogen resistance in vivo.

Citation Format: Rong Hu, Alan Zwart, Anni Warri, Robert Clarke. XBP1-NFkappaB signaling promotes antiestrogen resistance in breast cancer animal model. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-254. doi:10.1158/1538-7445.AM2013-LB-254
Abstract LB-262: Excessive Wnt activity is insufficient for intestinal tumor growth or regeneration without gp130/Jak2/Stat3 signaling.
Authors: Phesse Toby , Buchert Michael , Ernst Matthias
Published: August 2014

The majority of sporadic and familial colorectal cancers (CRC) arise from unregulated, excessive activation of the WNT signaling pathway as a result of impairment mutations in the tumor suppressor gene APC. Meanwhile, controlled activation of WNT signaling is required for intestinal regeneration in response to injury and ensures intestinal homeostasis. Thus far, however, therapeutic targeting of the WNT pathway has proven difficult in human disease. Here, we show genetically that activation of the cytokine-dependent gp130/Jak/Stat3 pathway augments intestinal regeneration in wild-type mice and promotes intestinal tumorigenesis in Apc mutant mice. Conversely, genetic restriction of gp130/Jak/Stat3 signaling suppresses regeneration and inhibits tumor burden despite persistent, excessive WNT activity. Moreover, therapeutic administration of the Jak2-kinase specific inhibitor AZD1480 in mouse models of either sporadic or inherited CRC effectively blocked de novo tumor initiation and progression. Likewise, AZD1480 suppressed the growth of human APC mutant, but not of isogenic APC wild-type, CRC cell lines in vitro and as tumor xenografts. We identify Stat3-dependent Bmi1 induction and the resulting repression of p16 and p21 as the mechanism by which the gp130/Jak/Stat3 pathway modulates the cellular response to excessive WNT signaling. We therefore propose that the gp130/Jak2/Stat3 pathway is rate-limiting selectively for the growth of APC mutant tumors, and that it provides a readily exploitable target for the therapeutic treatment of CRC.

Citation Format: Toby Phesse, Michael Buchert, Matthias Ernst. Excessive Wnt activity is insufficient for intestinal tumor growth or regeneration without gp130/Jak2/Stat3 signaling. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-262. doi:10.1158/1538-7445.AM2013-LB-262