bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 5129: Role of PRKD2 in HSP90 inhibition-mediated suppression of cancer growth
Authors: Azoitei Ninel , Diepold Kristina , Genze Felicitas , Rouhi Arefeh , Brobovich Susanne , Froehling Stefan , Chiosis Gabriela , Brunner Cornelia , Lint Johan van , Cronauer Marcus , Scholl Claudia , Seufferlein Thomas 
Published: May 2015

Abstract
In various types of malignancies, conventional forms of therapy such as surgery, radiation and chemotherapy are often ineffective. In the past decade, a convergence of scientific and technological advances has enabled the identification of molecular targets and signaling pathways specific to cancer cells, resulting in therapies with enhanced selectivity and efficacy and reduced toxicity. Protein kinases represent such molecular targets. We have recently shown that PRKD2 is a crucial regulator of tumor cell - endothelial cell communication in gastrointestinal tumors and demonstrated the kinase to be a novel regulator of glioblastoma growth. Here we report that HSP90/Cdc37 chaperone complex binds to and stabilizes PRKD2 in human cancer cells. RNAi-mediated ablation of HSP90 expression but also the pharmacological inhibition of the chaperone with two independent inhibitors induced degradation of PRKD2 in a broad range of human cancer cell lines and in vivo. Treatment of various cancer cell lines with proteasome inhibitors such as MG-132 or Bortezomib, followed by incubation with HSP90 inhibitors rescued the PRKD2 levels to the detergent-insoluble fraction suggesting that degradation of the kinase follows the proteasomal pathway. Kinetic experiments conducted with chaperone inhibitors demonstrated that PRKD2 was degraded in a time- and dose-dependent manner and this degradation was associated with the activation of the apoptotic programme both in vitro and in vivo. Furthermore, ectopic expression of the kinase protected cancer cells from the apoptotic effects of HSP90 abrogation suggesting PRKD2 as a protein whose depletion mediates the sensitivity of tumor cells to chaperone inhibition. Altogether, these findings 1) propose PRKD2 ablation through HSP90 inhibition as a potential therapeutic strategy with immediate implementation, 2) reveal the kinase as a crucial modulator of HSP90-mediated apoptotic effects and 3) promote the intensification of designing specific PRKD2 inhibitors and their implementation in targeted therapy in human cancer.
Citation Format: Ninel Azoitei, Kristina Diepold, Felicitas Genze, Arefeh Rouhi, Susanne Brobovich, Stefan Froehling, Gabriela Chiosis, Cornelia Brunner, Johan van Lint, Marcus Cronauer, Claudia Scholl, Thomas Seufferlein. Role of PRKD2 in HSP90 inhibition-mediated suppression of cancer growth. [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 5129. doi:10.1158/1538-7445.AM2014-5129
Abstract 513: Investigating stress-response pathways in pancreatic cancer cells using novel PERK inhibitors
Authors: Park Jihyun , Wang Qiantao , Kaoud Tamer S. , Tavares Clint D. J , Edupuganti Ramakrishna , Ren Pengyu , Dalby Kevin N. 
Published: May 2015

Abstract
An adaptive stress response mechanism, termed the unfolded protein response (UPR), is highly activated in a variety of tumor types to cope with ER stress and maintain protein homeostasis. PERK (PKR-like endoplasmic reticulum kinase) is one of the key components of the UPR. PERK is a Ser/Thr protein kinase whose active homodimer phosphorylates and inactivates eukaryotic initiation factor 2α (eIF2α), thereby inhibiting protein translation globally and reducing the load of newly synthesized proteins entering the ER. Previous studies demonstrated that cells with a compromised PERK signaling pathway are sensitive to hypoxic stress in vitro and form tumors that grow more slowly in vivo. Thus, selective inhibitors of PERK activity may be useful therapeutic candidates for the treatment of cancer. Using an HTS approach a number of lead compounds were identified with demonstrated ability to inhibit PERK kinase activity in vitro. The potent PERK inhibitors were further tested in pancreatic cancer cells to evaluate the modulation of the PERK-eIF2α-ATF4-CHOP signaling pathway. The effect of PERK inhibitors on cell viability was determined by an MTS assay. PERK inhibitors had dose-dependent effects on suppression of pancreatic cancer cell proliferation. Inhibitor-mediated PERK inhibition is associated with the down-regulation of PERK signaling and with the suppression of pancreatic cancer cell proliferation, suggesting their potential anticancer activities. Here we present new findings implicating additional inputs into this stress response.
Citation Format: Jihyun Park, Qiantao Wang, Tamer S. Kaoud, Clint D. J Tavares, Ramakrishna Edupuganti, Pengyu Ren, Kevin N. Dalby. Investigating stress-response pathways in pancreatic cancer cells using novel PERK inhibitors. [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 513. doi:10.1158/1538-7445.AM2014-513
Abstract 5133: Identification of FC101-interacting proteins by immunoprecipitation
Authors: Washington Dominique C. , Williams Amber D. , Williams-Hart Tara 
Published: May 2015

Abstract
Fusarochromanone (FC 101) is a small toxic metabolite produced by Fusarium equiseti, a fungus found on decaying cereal plants and food grains. FC101 has been shown to exhibit anti-angiogenic and anti-cancer activity on various mammalian cells. Previous studies have revealed that FC101 inhibits growth of 35 human cancer cells and reduces mouse tumor size almost two-fold with increased caspase3 expression in FC101-treated tumors. cDNA microarray analysis and RT-qPCR were used to identify differentially expressed genes in human bladder cancer cell lines (UM-UC14) and Saccharomyces cerevisiae (budding yeast) exposed to different concentrations of FC101. These genes encode proteins that represent possible molecular targets of FC101. The objective of this study is to identify proteins that interact with FC101 by immunopercipitation using an FC101 antibody in UM-UC14 cells. We predict FC101 molecular targets will be verified in future animal studies and eventually FC101 may be used as a chemotherapeutic agent.
Citation Format: Dominique C. Washington, Amber D. Williams, Tara Williams-Hart. Identification of FC101-interacting proteins by immunoprecipitation. [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 5133. doi:10.1158/1538-7445.AM2014-5133
Abstract 5135: A chromatin modifier from the 8p11 amplicon in luminal breast cancer
Authors: Ivey Brittany Turner , Guest Steve , Ethier Stephen P. 
Published: May 2015

Abstract
The chromosome 8p11-p12 amplicon is present in 12-15% of breast cancers, resulting in an increase in both copy number and expression of several chromatin modifiers in these tumors, including KAT6A, WHSC1L1, and ASH2L. Previous analyses in SUM52 breast cancer cells showed amplification and over-expression of KAT6A, and subsequent RNAi screening identified KAT6A as a potential driving oncogene. Also known as MYST3, KAT6A is a histone acetyltransferase (HAT) with intrinsic HAT activity towards itself and lysine residues on histone 2B, histone 3, and histone 4. Previously identified as a fusion partner with CREB binding protein (CREBBP) in acute myeloid leukemia, KAT6A is amplified in 8.7% of invasive breast cancers according to the Cancer Genome Atlas (TCGA). Knockdown of KAT6A with several shRNAs in SUM52 cells, a luminal breast cancer cell line harboring the 8p11 amplicon, resulted in reduced growth rate compared to non-silencing controls and profound loss of clonogenic capacity both in mono-layer and in soft agar. The normal cell line MCF10A, however, did not exhibit slower growth with knockdown of KAT6A, nor did other breast cancer cell lines without KAT6A amplfied. Interestingly, SUM52 cells with KAT6A knockdown formed fewer mammospheres in culture compared to non-silencing controls, suggesting a possible role for KAT6A in breast cancer stem cell activity and self-renewal. Further analysis of cell surface markers CD24 and CD44 in KAT6A knockdown cells revealed an increase in cells double positive for CD24 and CD44 expression, a characteristic of increased cell differentiation. Previous work from our laboratory identified FGFR2 as a driving oncogene in SUM52 cells. While FGFR inhibition can completely arrest the growth of these cells, it is completely reversible. Thus, exposure of SUM52 cells to FGFR inhibitors does not significantly affect the colony forming ability of the cells. By contrast, the colony forming efficiency of SUM52 KAT6A knockdown cells in the presence of the FGFR inhibitor PD170374 was significantly reduced compared to cells with KAT6A knockdown only. These data suggest that KAT6A may be a potential novel oncogene in breast cancers bearing the 8p11 amplicon and that it interacts with FGFR2 to regulate expression of transformed phenotypes. While there are other putative oncogenes in the amplicon, the identification of KAT6A as a driving oncogene suggests that chromatin-modifying enzymes are a key class of oncogenes in these cancers, and play an important role in the selection of this amplicon in luminal B breast cancers.
Citation Format: Brittany Turner Ivey, Steve Guest, Stephen P. Ethier. A chromatin modifier from the 8p11 amplicon in luminal breast 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 5135. doi:10.1158/1538-7445.AM2014-5135
Abstract 5139: MOF cooperates with DNA polymerase eta to repair intrastrand break induced by crosslinking agents
Authors: Singh Mayank , Gupta Arun , Komal Komal , Pandita Tej K. 
Published: May 2015

Abstract
The human MOF gene encodes a protein that specifically acetylates histone H4 at lysine 16 (H4K16ac). Reduced levels of H4K16ac correlate with a defective DNA damage response (DDR) and double-strand break (DSB) repair post ionizing radiation exposure. MOF overexpression increases cell survival to intrastrand crosslink inducing agents like cisplatin. DNA polymerase eta (Pol H), the product of the xeroderma pigmentosum variant (XPV) gene and a Y-family DNA polymerase, plays a pivotal role in translesion DNA synthesis and was found to interact with MOF. Its interaction with MOF increases in a dose dependent manner after exposure to intrastrand DNA damage induced by cisplatin. Pol H colocalized with phosphorylated MOF and γ-H2AX foci in cisplatin treated cells. Overexpression of MOF enhances recruitment of Pol H to laser induced DNA damage. This correlated with monoubiquitination of PCNA which has been shown to facilitate the switch between the replicative DNA polymerase with the low-fidelity polymerase eta to bypass UV or cisplatin-induced DNA lesions during replication. MOF was found to interact with PCNA and regulating the ubiquitination of PCNA thereby facilitating Pol H recruitment to DNA damage sites.
Note: This abstract was not presented at the meeting.
Citation Format: Mayank Singh, Arun Gupta, Komal Komal, Tej K. Pandita. MOF cooperates with DNA polymerase eta to repair intrastrand break induced by crosslinking agents. [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 5139. doi:10.1158/1538-7445.AM2014-5139
Abstract 514: Heat shock transcription factor-1 and heat shock protein 60 are important for lung carcinoma anoikis resistance
Authors: Carter Jack D. , Murphy Suzanne K. 
Published: May 2015

Abstract
Metastasis of cancer cells to distant sites leads to poor prognosis and comprises approximately 90% of cancer mortalities. It is evident that metastasis requires resistance to anoikis, an apoptotic program induced by detachment from the extracellular matrix. Heat shock proteins (HSPs) are molecular chaperones whose major functions include protein folding and suppression of apoptosis, and are transcriptionally regulated by heat shock transcription factor-1 (HSF1). HSF1 has been linked to metastasis and promotes anchorage-independent proliferation of breast cancer cells. HSP60 is a chaperone found in both the mitochondria and cytosol and is linked to metastasis and regulation of tumor cell apoptosis. To investigate whether HSF1 and HSP60 are necessary for anoikis resistance, anchorage-dependent lung carcinoma (A549, H460) and normal lung epithelial (Beas-2b) cells were suspended by plating on poly-2-hydroxyethyl-methacrylate-coated culture dishes. Anoikis induction was measured by executioner caspase-7 cleavage and PARP cleavage by western blot. Protein expression was measured by western blot. Small-interfering RNAs were used to inhibit hsf1 and hsp60. We show here that upon detachment for 24-48h, lung cancer cells resisted caspase-dependent anoikis in contrast to normal lung epithelial cells, with A549 cells showing the highest level of anoikis resistance. After 24h detachment there was increased phosphorylation of HSF1 on activating serine 326 in lung cancer cells. Antisense inhibition of hsf1 and hsp60 in attached lung cancer cells had minimal effects on caspase-7 and PARP cleavage. In contrast, hsf1 and hsp60 knockdown in cancer cells that were suspended for 24-48h initiated caspase-dependent anoikis. Furthermore, knockdown of hsf1 resulted in inhibition of HSP72, HSP40, and HSP27. HSP60 was not significantly inhibited with loss of HSF1. This data suggests that HSF1 and HSP60 are necessary for lung carcinoma anoikis resistance. Our work adds to evidence suggesting HSF1 and HSP60 are promising therapeutic targets for metastasis prevention. Although more detailed mechanistic evaluation is necessary, a therapeutic approach to induce anoikis in circulating tumor cells by modulating HSF1 or HSP60 may be promising.
Citation Format: Jack D. Carter, Suzanne K. Murphy. Heat shock transcription factor-1 and heat shock protein 60 are important for lung carcinoma anoikis resistance. [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 514. doi:10.1158/1538-7445.AM2014-514
Abstract 5142: Probing the molecular mechanism of EZH2 in rhabdoid tumors
Authors: Lira Michelle , Chan Ho Man , Gibaja Veronica 
Published: May 2015

Abstract
Proteins that regulate chromatin dynamics and post-translational modifications of histones are crucial transcriptional regulators, and are implicated in diverse cellular processes including proliferation, differentiation and genome integrity control. The Polycomb repressive complex 2 (PRC2) plays a key role in the maintenance of transcriptional repression of genes necessary for normal embryonic development. Enhancer of Zeste homolog 2 (EZH2) is the catalytic subunit of PRC2 and methylates lysine 27 on histone 3 (H3K27).Overexpression and mutations of EZH2 have been reported to promote tumorigenesis [1,2]. Malignant Rhabdoid Tumors (MRTs) are highly aggressive tumors of soft tissues showing high sensitivity to an EZH2 inhibitor [1,3,4].Treatment with a highly selective and potent EZH2 inhibitor (EI1) leads to induction of p16 expression, sustained growth arrest and senescence in G401, a MRT cell line model (Fig. 1) (3, 4). Taking advantage of the strong anti-proliferative effect of EI1 in G401, we performed an shRNA screen to identify molecular targets that will confer resistance to EI1-mediated growth arrest. We hypothesized that such targets will provide novel insight of EZH2 biology in rhabdoid cancers, and may be relevant to potential mechanisms of resistance.
Citation Format: Michelle Lira, Ho Man Chan, Veronica Gibaja. Probing the molecular mechanism of EZH2 in rhabdoid tumors. [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 5142. doi:10.1158/1538-7445.AM2014-5142
Abstract 5143: KDM3A promotes cell growth and cisplatin-resistance in ovarian cancer cells
Authors: Ramadoss Sivakumar , Sen Suvajit , Chaudhuri Gautam , Farias-Eisner Robin 
Published: May 2015

Abstract
Background: Ovarian cancer is the most lethal gynecological cancer affecting the women worldwide. One of the main challenging hurdles in ovarian cancer treatment is the high recurrence rate due to therapeutic resistance. Recent evidences showed that JmjC-domain (JMJD) containing histone demethylases plays a critical role in controlling gene expression during normal development and cancer progression.
Aims: To determine whether histone demethylase plays a role in ovarian cancer progression and therapeutic resistance.
Methods: We developed cisplatin-resistance ovarian cancer cell lines SKOV-3 and OVCAR-5 and isolated total RNA to screen the expression pattern of JMJD family genes by real-time RT-PCR. We performed stable knock-down of KDM3A by lentiviral mediated ShRNA transfection and studied its effects on cell proliferation and apoptosis by MTT assay and western blot analysis (PARP, caspase-3), respectively. We also determined the effect of KDM3A knock-down on cell cycle and apoptosis regulators by western blot.
Results: Our observations indicated the differential expression of various JMJD family proteins between cisplatin-resistance and sensitive cell lines. To further evaluate our results, we also tested the expression of those differentially expressed JMJD proteins in a widely used cisplatin-resistance and sensitive A2780 cell lines. We observed that KDM3A/JMJD1A is consistently overexpressed in all the cisplatin-resistance cell lines studied. Next, we stably knock-down KDM3A in cisplatin-resistance OVCAR-5 and A2780 cell lines. More interestingly, we found that KDM3A depletion inhibited cell proliferation, induced apoptosis and enhanced the sensitivity to cisplatin treatment. Further, we confirmed that the important regulators of cell cycle and apoptosis including p21 and Bcl-2 were modulated by KDM3A knock-down.
Conclusions: Our results indicate that KDM3A is a critical epigenetic factor required for the ovarian cancer growth by promoting cell proliferation and cisplatin-resistance. Our findings might have important clinical implications in targeting ovarian cancer cells by using specific histone demethylase inhibitors.
Grant support: This work was supported by Carl and Roberta Deutsch, and Kelly Day Foundations.
Citation Format: Sivakumar Ramadoss, Suvajit Sen, Gautam Chaudhuri, Robin Farias-Eisner. KDM3A promotes cell growth and cisplatin-resistance in ovarian 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 5143. doi:10.1158/1538-7445.AM2014-5143
Abstract 5152: Mechanism and therapeutic potential of the histone demethylase GASC1 in castration-resistant prostate cancer
Authors: Labbe Roselyne M. , Ye Qin , Holowatyj Andreana , Zhang Lihong , Yang Zeng Quan 
Published: May 2015

Abstract
The histone lysine demethylase, GASC1 (Gene Amplified in Squamous Cell Carcinoma 1) is an epigenetic regulatory protein both highly expressed during mammalian embryogenesis and overexpressed in several types of cancer, including aggressive Castration Resistant Prostate Cancer (CRPC). GASC1 mainly catalyzes demethylation of tri- and di-methylated forms of histone H3 lysine 9 (H3K9me3/me2) epigenetic repressive marks, regulating gene expression and chromatin architecture. This research aims to elucidate the fundamental mechanism by which GASC1 dysregulation contributes to CRPC progression, as well as to evaluate its potential as a therapeutic target against aggressive prostate cancer. Previously, our lab and others have shown that GASC1 interacts with the androgen receptor (AR) and functions as a co-activator of AR-induced transcription in prostate cancer. We have used an shRNA approach to determine whether GASC1 knockdown affects the proliferation and transformation of CRPC cells. We found that knocking down GASC1 inhibits the growth and colony formation of C4-2B and CWR22Rv1 cells in vitro. Knockdown also reduced transcript levels of classical and CRPC-specific AR target genes in either the presence or absence of the AR ligand. As a result, we are evaluating the therapeutic potential of novel and highly specific lysine demethylase inhibitors towards abating GASC1 function in prostate cancer cells in vitro. We have recently determined that one of these novel inhibitors is highly effective in modulating the survival and proliferation of several prostate cancer cell lines including CRPC lines with IC50 values, all well under 1 uM. Together, our data demonstrates that GASC1 is a therapeutically relevant target in controlling and preventing the emergence of prostate cancers, with particular application against aggressive CRPC subtypes.
Citation Format: Roselyne M. Labbe, Qin Ye, Andreana Holowatyj, Lihong Zhang, Zeng Quan Yang. Mechanism and therapeutic potential of the histone demethylase GASC1 in castration-resistant prostate 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 5152. doi:10.1158/1538-7445.AM2014-5152
Abstract 5156: The oncogenic polycomb histone methyltransferase EZH2 methylates lysine 120 on histone H2B and competes ubiquitination in human cancer
Authors: Hamamoto Ryuji , Nakamura Yusuke 
Published: May 2015

Abstract
The histone methyltransferase EZH2 is known to be a polycomb protein homologus to Drosophila enhancer of zeste and catalyzes the addition of methyl groups to histone H3 at lysine 27 (H3K27). We previously reported that EZH2 was overexpressed in various types of cancer and plays a crucial role in the cell cycle regulation of cancer cells. In this study, we demonstrated that EZH2 has the function to mono-methylated lysine 120 on histone H2B (H2BK120). EZH2-dependent H2BK120 methylation in cancer cells was confirmed with an H2BK120 methylation-specific antibody. Overexpression of EZH2 significantly attenuated the ubiquitination of H2BK120, a key post-translational modification of histones for transcriptional regulation. Concordantly, knockdown of EZH2 increased the ubiquitination level of H2BK120, suggesting that the methylation of H2BK120 by EZH2 may competitively inhibit the ubiquitination of H2BK120. Subsequent ChIP-Seq and microarray analyses identified downstream candidate genes regulated by EZH2 through the methylation of H2BK120. This is the first report to describe a novel substrate of EZH2, H2BK120, unveiling a new aspect of EZH2 functions in human carcinogenesis.
Citation Format: Ryuji Hamamoto, Yusuke Nakamura. The oncogenic polycomb histone methyltransferase EZH2 methylates lysine 120 on histone H2B and competes ubiquitination in human 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 5156. doi:10.1158/1538-7445.AM2014-5156