bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 228: Withaferin A downregulates tubulins and covalently binds β-tubulin at cysteine-303 in human breast cancer cells
Authors: Singh Shivendra V. , Antony Marie Lue , Lee Joomin , Hahm Eun-Ryeong , Kim Su-Hyeong , Romero Guillermo , Marcus Adam I. , Yang Zhen , Kumari Vandana , Ji Xinhua , Vowell Courtney L. , Wipf Peter , Uechi Guy T. , Yates Nathan A. 
Published: May 2015

Abstract
We have shown previously that withaferin A (WA), a C5,C6-epoxy steroidal lactone derived from an Ayurvedic medicine plant (Withania somnifera), not only inhibits growth of human breast cancer cells in vitro and in vivo but also prevents mammary cancer development in a transgenic mouse model without any toxicity. However, the mechanisms underlying cancer preventive effect of WA are not fully understood. Herein, we report that tubulin is a novel target of WA in human breast cancer cells. WA treatment resulted in G2 and mitotic arrest in MCF-7 (estrogen-receptor positive), SK-BR-3 (estrogen-receptor negative), and SUM159 (triple-negative) cells in association with a marked decrease in protein level of β-tubulin. These effects were not observed with the naturally-occurring C6,C7-epoxy analogs of WA (withanone and withanolide A). In addition, a non-tumorigenic normal human mammary epithelial cell line (MCF-10A) was markedly more resistant to mitotic arrest and tubulin downregulation by WA treatment compared with breast cancer cells. Downregulation of tubulin protein in WA-treated cells was due to transcriptional repression as well as proteasomal degradation. Vehicle-treated control breast cancer cells exhibited a normal bi-polar spindle with chromosomes aligned along the metaphase plate. In contrast, WA treatment led to a severe disruption of the normal spindle morphology in breast cancer cells. Unlike breast cancer cells, WA-treated MCF-10A cells exhibited aggregation of tubulin around nucleus. NMR analyses revealed that the A-ring enone in WA, but not in withanone or withanolide A, was highly reactive with cysteamine and rapidly succumbed to irreversible nucleophilic addition. Mass spectrometry demonstrated direct covalent binding of WA at cysteine-303 of β-tubulin in MCF-7 cells. Molecular docking studies indicated that the WA-binding pocket was located on the surface of the β-tubulin and characterized by a hydrophobic floor, a hydrophobic wall, and a charge-balanced hydrophilic entrance. These results provide novel insights into the mechanism of anticancer effect of WA. This work was supported by the grants RO1 CA142604 and P30 CA047904 awarded by the National Cancer Institute.
Citation Format: Shivendra V. Singh, Marie Lue Antony, Joomin Lee, Eun-Ryeong Hahm, Su-Hyeong Kim, Guillermo Romero, Adam I. Marcus, Zhen Yang, Vandana Kumari, Xinhua Ji, Courtney L. Vowell, Peter Wipf, Guy T. Uechi, Nathan A. Yates. Withaferin A downregulates tubulins and covalently binds β-tubulin at cysteine-303 in human breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 228. doi:10.1158/1538-7445.AM2014-228
Abstract 2280: Role of apoptosis signal-regulating kinase 1 in the cell apoptosis in oral leukoplakia
Authors: Tang Xiaofei , Zhang Jian-Fei , Niu Wen-wen , Zhang Min 
Published: May 2015

Abstract
Oral leukoplakia is a common precancerous lesion. The mechanism is not clear. The aim is to investigate the roles of apoptosis signal-regulating kinase 1(ASK1) in the cell apoptosis in oral leukoplakia. Archival tissue sections of 10 oral leukoplakia,23 oral leukoplakia with mild to moderate dysplasia, 7 normal oral mucosa were detected by real time PCR and immunohistochemical staining of markers of ASK1 and p-ASK1.The cell apoptosis was detected by terminal deoxynucleotidyl transferase-mediated nucleotide shift enzyme(TdT) mediated d-UTP end labeling(TUNEL). The results showed The mRNA and protein expression of ASK1 in oral leukoplakia with mild to moderate dysplasia was higher than the normal mucosa(p&lt;0.05).From oral normal mucosa to oral leukoplakia to mild to moderate dysplasia, the expression of p-ASK1 was increased with the increasing grade( p&lt;0.05).The apoptosis in oral leukoplakia and mild to moderate dysplasia increased more than normal mucose(p&lt;0.05). It suggests that ASK1 and p-ASK1 are positive correlation with the increased apoptosis in the development of oral leukoplakia, its related signal pathways and cascade may play an important role in the cell apoptosis in oral leukoplakia.
Citation Format: Xiaofei Tang, Jian-Fei Zhang, Wen-wen Niu, Min Zhang. Role of apoptosis signal-regulating kinase 1 in the cell apoptosis in oral leukoplakia. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2280. doi:10.1158/1538-7445.AM2014-2280
Abstract 2283: Potent curcumin analog FLLL-12 targets both intrinsic and extrinsic signaling pathways to induce apoptosis in lung cancers
Authors: Amin A.R.M. Ruhul , Haque Abedul , Rahman Mohammad A. , Fuchs James R. , Chen Zhuo G. , Shin Dong M. 
Published: May 2015

Abstract
Background: Curcumin is the major bioactive compound isolated from the rhizome of Curcuma longa (turmeric). Despite its high margin of safety and efficacy against various types of cancers, the potential utility of curcumin as a chemopreventive/chemotherapeutic drug is compromised by its low bioavailability and poor selectivity. To circumvent these problems, more potent and selective curcumin analogues have been developed. In the current study, we investigated the mechanism of apoptosis of one such synthetic analogue, FLLL-12, against lung cancers. This compound was reported to exhibit potent anti-tumor activity against prostate, colon and breast cancer cell lines. However, its mechanism of growth inhibition has yet to be elucidated.
Methods: Multiple premalignant and fully transformed lung cancer cell lines were used throughout the study. SRB assay was used to measure cell growth inhibition. Annexin V staining was conducted for apoptosis assay. Expression of mRNAs and proteins were measured by RT-PCR and Western blotting, respectively. Gene overexpression and knockdown strategies were used to activate or shut down of specific proteins.
Results: IC50 values and apoptosis assay results showed that FLLL-12 was ∼10-fold more potent than the natural parent compound, curcumin, against lung cancer cells. Further mechanistic studies revealed that FLLL-12 induced the expression of DR5, inhibited the protein expression of EGFR, p-AKT, AKT and Bcl-2 and increased the expression of BIM. Analysis of mRNA expression suggested that FLLL-12 strongly inhibited the mRNA expression of EGFR and AKT, whereas the expression of Bcl-2 and Bim mRNAs remained unchanged. FLLL-12 also induced the expression of p53 and p73. However, inactivation of these proteins with their dominant negative construct or siRNA had no significant effects on apoptosis induction.
Conclusions: Our results strongly suggest that FLLL-12 is a potent curcumin analog that induces apoptosis of lung cancer cell lines by targeting: (1) intrinsic pathways via transcriptional inhibition of EGFR and AKT and induction of BIM, and (2) extrinsic pathway via induction of DR5. Future in vivo studies using appropriate animal models are warranted for further development of this promising compound for cancer prevention and/or treatment for lung cancer.
(Supported by R03CA171663, P50CA128613 and Robbins Scholar Award of Winship Cancer Institute of Emory University).
Citation Format: A.R.M. Ruhul Amin, Abedul Haque, Mohammad A. Rahman, James R. Fuchs, Zhuo G. Chen, Dong M. Shin. Potent curcumin analog FLLL-12 targets both intrinsic and extrinsic signaling pathways to induce apoptosis in lung cancers. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2283. doi:10.1158/1538-7445.AM2014-2283
Abstract 2288: Pharmacological inhibition of B-Raf/MEK/ERK signaling suppresses DR5 expression and impairs cancer cell response to DR5 activation-induced apoptosis
Authors: Oh You-Take , Yue Ping , Owonikoko Taofeek K. , Khuri Fadlo R. , Sun Shi-Yong 
Published: May 2015

Abstract
Inhibition of B-Raf/MEK/ERK signaling is an effective therapeutic strategy against certain types of cancers such as melanoma and thyroid cancer. While demonstrated to be effective anticancer agents, B-Raf inhibitors have also been associated with increased risk of secondary neoplasms. The induction of apoptosis following ligation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) with its receptor, death receptor 5 (DR5), offers a potent anticancer strategy. Importantly, this is also a natural immunosurveillance mechanism against cancer cells. We previously demonstrated that activated B-Raf/MEK/ERK signaling positively regulates DR5 expression. Hence, our current work seeks to address whether B-Raf/MEK/ERK inhibition and the consequent suppression of DR5 expression impedes cancer cell response to DR5 activation-induced apoptosis. We found that both B-Raf (e.g., PLX4032) and MEK inhibitors (e.g., AZD6244 and PD0325901) effectively inhibited ERK1/2 phosphorylation and reduced DR5 levels in both human thyroid cancer and melanoma cells. Similar to the observed effect of genetic knockdown of the B-Raf gene, pretreatment of cancer cell lines with either B-Raf or MEK inhibitors attenuated or abolished cellular apoptotic response induced by TRAIL or the DR5 agonistic antibody AMG655. Our findings clearly showed that inhibition of the B-Raf/MEK/ERK signaling suppresses DR5 expression and impairs DR5 activation-induced apoptosis. These findings warrant further investigation of potential negative impact of B-Raf or MEK inhibition on TRAIL- or DR5-targeted cancer therapy and on TRAIL/DR5-mediated cancer immunosurveillance.
(This study was supported by the Georgia Cancer Coalition Distinguished Cancer Scholar award, NIH/NCI SPORE P50 grant CA128613 and
Winship Cancer Institute Robbins Scholar award. FR Khuri and SY Sun are Georgia Cancer Coalition Distinguished Cancer Scholars. YT Oh is a recipient of Winship Cancer Institute Robbins Scholar award)
Citation Format: You-Take Oh, Ping Yue, Taofeek K. Owonikoko, Fadlo R. Khuri, Shi-Yong Sun. Pharmacological inhibition of B-Raf/MEK/ERK signaling suppresses DR5 expression and impairs cancer cell response to DR5 activation-induced apoptosis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2288. doi:10.1158/1538-7445.AM2014-2288
Abstract 2290: Rational targeting of inhibitor of apoptosis proteins (IAPs) for effective therapy of colorectal cancer
Authors: Crawford Nyree T. , Dunne Philip D. , Johnston Patrick G. , Waugh David J. , Longley Daniel B. 
Published: May 2015

Abstract
Background
Inhibitor of Apoptosis Proteins (IAPs) are anti-apoptotic proteins which suppress the activation of caspases. IAP proteins have been shown to be overexpressed in several cancers, including colorectal cancer and correlate with poor prognosis. SMAC mimetics are a class of apoptosis inducing drugs that target IAPs by mimicking the N-terminal IAP-binding motif of SMAC. Colorectal cancer has a pro-inflammatory microenvironment with high levels of TNFα. The aims of this study were to assess the efficacy of SMAC mimetic treatment in colorectal cancer.
Methods
Colorectal cell lines were treated with SMAC mimetics and cell viability was determined using MTT assays. Apoptosis was assessed by Western blotting for caspase activation and PARP cleavage and Flow Cytometry using Annexin V/PI staining. Protein-protein interactions were assessed using co-immunoprecipitation experiments. The pro-inflammatory microenvironment was modelled by addition of exogenous TNFα and also media transfer from and direct co-cultures with macrophages (THP-1, monocytic cell line).
Results
Colorectal cell lines were resistant to SMAC mimetic treatment alone unless co-cultured with TNFα. Pretreatment of colorectal cancer cells with 5-FU and oxaliplatin sensitised the cells to SMAC mimetic treatment. THP-1 cells were found to secrete soluble TNFα and media transfer experiments and also co-culture with colorectal cell lines, sensitised the cancer cells to SMAC mimetic mediated cell death. Cell death under these conditions was found to be dependent on soluble TNFα through the utilisation of neutralising antibodies.
Conclusion
Our results to date suggest that the pro-inflammatory microenvironment of colorectal cancer could be exploited to target overexpressed IAP proteins leading to cell death.
Citation Format: Nyree T. Crawford, Philip D. Dunne, Patrick G. Johnston, David J. Waugh, Daniel B. Longley. Rational targeting of inhibitor of apoptosis proteins (IAPs) for effective therapy of colorectal cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2290. doi:10.1158/1538-7445.AM2014-2290
Abstract 2292: Epigenetic alterations in Barrett's esophagus and esophageal adenocarcinoma: identification and evaluation of potential biomarkers
Authors: Stockdale Rachele M. , Kaz Andrew M. , Morris Shelli M. , Chak Amitabh , Willis Joseph , Brenner Dean , Anandabapasathy Sharmila , Westerhoff Maria , Wong Chao-Jen , Barnholtz-Sloan Jill , Chen Yanwen , Grady William M. 
Published: May 2015

Abstract
Patients diagnosed with esophageal adenocarcinoma (EAC) have poor long-term survival rates. Currently, patients identified with Barrett's esophagus (BE), the strongest risk factor for EAC, are placed in costly and invasive surveillance programs. The impact of these surveillance programs on decreasing EAC related mortality is debatable, presumably because many patients with BE are not diagnosed until they develop cancer and because of suboptimal BE risk markers for EAC. Thus, there is a need for more accurate biomarkers. Epigenetic alterations in BE have the potential to be detection and risk markers for BE and EAC. In order to identify individual gene methylation patterns of normal squamous (SQ) epithelium, BE, low-grade dysplasia, high-grade dysplasia and EAC tissues, we have conducted genome-wide methylation assessments of these tissue types using HumanMethylation450 arrays (Illumina). Unique methylation signatures for each histological subtype have been identified by unsupervised clustering. Additionally, we determined the mean methylation state (‘beta value’) for more than 480,000 CpGs for each sample group. After normalization and filtering, differentially methylated loci (FDR p &lt; 0.05) with mean beta values with differences greater than 0.20 between the different tissue types were used to identify potential biomarkers. These biomarkers were then subjected to technical and clinical validation studies. We have currently identified and validated four potential biomarkers that may be useful in detection assays for BE and EAC. We have found two CpGs that distinguish EAC from BE, and two other CpGs that distinguish BE from SQ epithelium. The best performing biomarker has 100% sensitivity and 87.5% specificity in its ability to distinguish BE from EAC in the validation set of tissue samples. We presently have a number of additional candidates in various stages of validation. In summary, we have shown that differential methylation patterns exist between the various stages of progression from normal SQ epithelium to BE and ultimately EAC. Furthermore, some of these methylated CpGs have potential to be used as detection markers for BE or EAC.
Citation Format: Rachele M. Stockdale, Andrew M. Kaz, Shelli M. Morris, Amitabh Chak, Joseph Willis, Dean Brenner, Sharmila Anandabapasathy, Maria Westerhoff, Chao-Jen Wong, Jill Barnholtz-Sloan, Yanwen Chen, William M. Grady. Epigenetic alterations in Barrett's esophagus and esophageal adenocarcinoma: identification and evaluation of potential biomarkers. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2292. doi:10.1158/1538-7445.AM2014-2292
Abstract 2295: Epigenetic regulation of KLHL34 may be predictive of pathologic response to preoperative chemoradiotherapy in rectal cancer patients
Authors: Ha Yejin 
Published: May 2015

Abstract
Aims: Radiation therapy is used to treat half of all cancer patients, but response to radiation therapy varies widely among patients. Studies aimed at predicting individual responsiveness to preoperative radiation therapy (CRT) are urgently needed, especially considering the risks associated with poorly responsive patients.
Methods: This study adopted a three-step process to select radiosensitive candidates of methylation genes. In the first step, a genome-wide creening of methylation genes was performed using Infinium humanMethylation450K Beadchip according to the correlation with istopathologic tumor regression grade (TRG) of 45 patients with locally advanced rectal cancer (LARC). In the second step, methylation status of selected sites was analyzed with pyrosequencing in the other 98 LARC patients. Finally, candidate gene identified by second screening was verified by biological utility assessment using cell viability assays of transfected colorectal cancer (CRC) cells. Results: Genome-wide creening identified that hypermethylation of 7 CpG sites (DZIP cg24107021, DZIP cg26886381, ZEB1 cg04430381, DKK3 cg041006961, STL cg00991794, KLHL34 cg01828474, ARHGAP6 cg07828380) were associated with preoperative CRT responses. Patients carrying hypermethylated KLHL34 cg14232291 were confirmed to show radiosensitivity by pyrosequencing in additional patients. Knockdown of KLHL34 significantly reduced colony formation and increased cytotoxicity in LoVo cells. It increased radiation induced caspase-3 activity and sub G1 population.Conclusions: In this study, we showed that methylation status of KLHL34 cg14232291 may be a predictive marker of radiosensitivity to preoperative CRT, although further validation is needed in large cohorts.
Citation Format: Yejin Ha. Epigenetic regulation of KLHL34 may be predictive of pathologic response to preoperative chemoradiotherapy in rectal cancer patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2295. doi:10.1158/1538-7445.AM2014-2295
Abstract 2296: IDH2 mutation induced histone and DNA hypermethylation is progressively reversed by small molecule inhibition
Authors: Kernytsky Andrew , Wang Fang , Hansen Erica , Schalm Stefanie , Straley Kimberly , Gliser Camelia , Yang Hua , Travins Jeremy , Murray Stuart , Dorsch Marion , Agresta Sam , Schenkein David P. , Biller Scott A. , Su Shinsan M. , Liu Wei , Yen Katharine E. 
Published: May 2015

Abstract
Mutations of IDH1 and IDH2 which produce the oncometabolite 2-hydroxyglutarate (2HG), have been identified in several tumors including acute myeloid leukemia (AML). Recent studies have shown that expression of the IDH mutant enzymes results in high levels of 2HG and a block in cellular differentiation that can be reversed with IDH-mutant specific small molecule inhibitors. To further understand the role of IDH mutations in cancer, we conducted mechanistic studies in the TF-1 IDH2 R140Q erythroleukemia model system and found that IDH2 mutant expression caused both histone and genomic DNA methylation changes that can be reversed when IDH2 mutant activity is inhibited. Specifically, histone hypermethylation is rapidly reversed within days whereas reversal of DNA hypermethylation proceeds in a progressive manner over the course of weeks. Pathway enrichment analysis revealed several pathways involved in tumorigenesis of leukemia and lymphoma, indicating a selective modulation of relevant cancer genes by IDH mutations. As methylation of DNA and histones is closely linked to mRNA expression and differentiation, these results indicate that IDH2 mutant inhibition may function as a cancer therapy via histone and DNA demethylation at genes involved in differentiation and tumorigenesis.
Citation Format: Andrew Kernytsky, Fang Wang, Erica Hansen, Stefanie Schalm, Kimberly Straley, Camelia Gliser, Hua Yang, Jeremy Travins, Stuart Murray, Marion Dorsch, Sam Agresta, David P. Schenkein, Scott A. Biller, Shinsan M. Su, Wei Liu, Katharine E. Yen. IDH2 mutation induced histone and DNA hypermethylation is progressively reversed by small molecule inhibition. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2296. doi:10.1158/1538-7445.AM2014-2296
Abstract 2319: Dynamics of TET methylcytosine dioxygenases in 5-methylcytosine and 5-hydroxymethylcytosine patterning in human cancer cells
Authors: Putiri Emily L. , Tiedemann Rochelle L. , Choi Jeong-Hyeon , Robertson Keith D. 
Published: May 2015

Abstract
The Ten-eleven translocation (TET) family of dioxygenases hydroxylate 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) in DNA. 5mC provides important epigenetic instructions during development, and its aberrant control is a major contributor to cellular transformation; however TET functions in regulating the epigenome, particularly in cancer, remain largely unknown. We targeted TET1, TET2, and TET3 for siRNA-mediated depletion in pluripotent human embryonic carcinoma cells and examined the impact on 5mC and 5hmC genome-wide localization. TET1, TET2, and TET3 co-regulate 5hmC at many sites, and depletion of only one of the TETs is sufficient to reduce 5hmC at these co-regulated sites, suggesting a functional co-dependence for TETs. Depletion of TET1 and TET2 had the greatest impact on 5hmC levels at high and low CpG density promoters, respectively, indicating that TETs exhibit DNA sequence-based functional specificity. All TETs prevent hypermethylation throughout the genome, especially in CpG island shores, where TET depletion resulted in prolific hypermethylation. Promoter hypermethylation resulting from TET depletion was associated with histone H2AK119 monoubiquitination, DNMT1, and DNMT3B occupancy. Surprisingly, TETs also promote cytosine methylation, as many loci became hypomethylated following TET depletion. Induction of differentiation generally caused 5hmC reduction, except at transcriptionally activated genes, which become enriched for 5hmC. Importantly, genes prone to promoter hypermethylation in cancer become depleted of intragenic 5hmC and 5mC with TET deficiency. This study highlights the multi-dimensional functions of TETs in mediating DNA methylation, hydroxymethylation, and gene expression patterns, and the results reveal that chromatin landscape and DNA sequence composition are regulators of TET function.
Citation Format: Emily L. Putiri, Rochelle L. Tiedemann, Jeong-Hyeon Choi, Keith D. Robertson. Dynamics of TET methylcytosine dioxygenases in 5-methylcytosine and 5-hydroxymethylcytosine patterning in human cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2319. doi:10.1158/1538-7445.AM2014-2319