bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2881: Deubiquitinase Usp9x controls tumorigenicity through regulation of the Ets-1 transcription factor in melanoma
Authors: Potu Harish , Peterson Luke F. Peterson , Kandarpa Malathi Kandarpa , Pal Anupama Pal , Sun Hanshi Sun , Harms Paul W. Harms , Hollenhorst Peter C. Hollenhorst , Eskiocak Ugur Eskiocak , Talpaz Moshe Talpaz , Donato Nicholas J. Donato 
Published: July 2016

Abstract
Transcription factors are frequently deregulated in cancer cells and may be good therapeutic targets, but few successful targeting strategies have been reported. Deubiquitinases (DUBs) are specialized enzymes that regulate the ubiquitin (Ub) content on many proteins and DUB expression and activity are elevated in a number of cancers where they can act to alter tumor suppressor and/or oncoprotein levels. We previously described Usp9x activity and expression in melanoma; here we sought to investigate its role in primary melanoma and metastatic disease. Usp9x was upregulated in tumor cells compared to normal melanocytes and Usp9x expression and activity were found to be essential for 3D growth and melanoma tumor expansion in vivo. We defined the Usp9x ubiquitinated protein landscape and demonstrate that Usp9x regulates Ets-1, a cancer-promoting transcription factor. Usp9x binds, deubiquitinates and thereby stabilizes Ets-1 protein, and primary tissue and tumor analysis demonstrated elevated and coincident Usp9x/Ets-1 protein expression in melanoma compared to normal skin or benign nevi. Usp9x knockdown or Usp9x inhibition with small molecule G9 reduced Ets-1 protein levels and blocked tumor growth in vitro and in vivo. Conversely, Usp9x overexpression in melanoma cells increased Ets-1 protein levels and enhanced 3D tumor growth in vitro and in vivo, which were all reversible by treatment with G9. We conclude that Usp9x is essential for Ets-1 protein stability and may be therapeutically exploited with small molecule Usp9x inhibitors to reduce Ets-1-dependent gene expression and tumorigenicity.
Citation Format: Harish Potu, Luke F. Peterson Peterson, Malathi Kandarpa Kandarpa, Anupama Pal Pal, Hanshi Sun Sun, Paul W. Harms Harms, Peter C. Hollenhorst Hollenhorst, Ugur Eskiocak Eskiocak, Moshe Talpaz Talpaz, Nicholas J. Donato Donato. Deubiquitinase Usp9x controls tumorigenicity through regulation of the Ets-1 transcription factor in melanoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2881.
Abstract 2882: HnRNP Q1, a novel translational regulator for Aurora-A protein synthesis in colorectal cancer
Authors: Lai Chien-Hsien , Hung Liang-Yi 
Published: July 2016

Abstract
HnRNP Q1 is a multifunctional RNA-binding protein and has an abundant expression level compared with hnRNP Q member. In colorectal cancer, hnRNP Q has been reported to associate with cell proliferation, but the underlying mechanism is still unclear. By RNA-immunoprecipitation assay following next-generation sequencing (NGS), a group of cell cycle-related genes was identified to be targeted by hnRNP Q1, including Aurora-A kinase. Aurora-A is a cell cycle dependent kinase involved in regulating centrosome duplication, maturation and spindle assembly during mitosis. Abnormally elevated Aurora-A will cause mitotic defects and aneuploidy, which might lead to genomic instability and tumorigenesis. Our previous work has demonstrated that Aurora-A can be translational up-regulated in colorectal cancer. In order to investigate the role of hnRNP Q1 in Aurora-A expression, GFP-hnNRP Q1 was overexpressed in colorectal cancer cells. We found that Aurora-A protein, but not the mRNA level, was up-regulated in those GFP-hnRNP Q1-overexpressing cells. By biotin pull down and Biacore analysis, we revealed that hnRNP Q1 binds to the 5’-UTRs of Aurora-A mRNA directly, and their interacting domain was mapped. Importantly, we found that hnRNP Q1 can enhance Aurora-A protein synthesis through IRES-mediated translational regulation in a cell cycle-regulated manner by ribosomal protein S6 immunoprecipitation, polysome fractionation and bicistronic reporter assay. CCK-8 assay, colony formation and in vivo xenograft assay all suggested that overexpression of hnRNP Q1 can promote cell proliferation and tumorigenesis of colorectal cancer cells. In addition, the expression level of hnRNP Q1 is positively correlated with Aurora-A in clinical colorectal cancer tissues. Taken together, our data indicate that hnRNP Q1 is a novel trans-acting factor that binds to Aurora-A 5’-UTRs and regulates its translation, which may increase cell proliferation and contribute to the tumorigenesis of colorectal cancer.
Citation Format: Chien-Hsien Lai, Liang-Yi Hung. HnRNP Q1, a novel translational regulator for Aurora-A protein synthesis in colorectal cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2882.
Abstract 2886: KLF8 phosphorylation at Serine 48 by ERK2 is critical for its stability and function
Authors: Lahiri Satadru , Lu Heng , Mukherjee Debarati , Yu Lin , Zhao Jihe 
Published: July 2016

Abstract
Krüppel-like factor 8 (KLF8) is a member of Krüppel like family transcription factor which was found to be upregulated in different types of cancers, primarily breast and ovarian cancer. It transcriptionally activates a host of downstream effectors like CyclinD1, EGFR, MMP9, and EPSTI1 to promote cell proliferation, cancer cell invasion and migration. Additionally, KLF8 transcriptionally represses E-cadherin to induce epithelial to mesenchymal transition and oncogenic transformation of cell. As such, KLF8 plays a central role in cancer progression. Several types of post-translational modifications including sumoylation, acetylation, ubiquitylation and PARylation have been discovered that regulate KLF8's function KLF8 has been shown to consistently migrate as doublet on SDS-PAGE. However, the reason for this motility shift of KLF8 has remained mysterious. We performed a series of experiments to determine the mechanism(s) behind this motility shift of KLF8. Truncation mutation showed that deletion of the first 50 amino acid residues, but not other regions, caused disappearance of the top band of the doublet, suggesting that the N50 region is responsible for the motility shift. Phosphatase treatment resulted in the same change in wild-type KLF8 protein, indicating that phosphorylation in the N50 region is causal to the motility shift. Further deletion and point mutation in this region identified Serine 48 as a novel phosphorylation site for KLF8. Interestingly, these experiments also identified KLF8 N terminal 31-40 region to play an important role in regulating the S48 phosphorylation and the motility shift. Our study identified that phosphorylation at Serine 48 is critical in maintaining KLF8 stability. Finally, we demonstrated that abolishing KLF8 S48 phosphorylation inhibits KLF8 mediated cancer cell migration. Kinase inhibitors treatment showed that ERK2 is the kinase responsible for KLF8 Serine 48 phosphorylation. Furthermore we identified that phosphorylated KLF8 acts as a mask to protect unphosphorylated KLF8. Overall this study identifies a novel phosphorylation site of KLF8 and a hitherto unknown link between ERK2 and KLF8 that is critical for maintaining its overall stability and function.
Citation Format: Satadru Lahiri, Heng Lu, Debarati Mukherjee, Lin Yu, Jihe Zhao. KLF8 phosphorylation at Serine 48 by ERK2 is critical for its stability and function. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2886.
Abstract 2888: Identification of an NKX3.1-G9a-UTY regulatory network that controls proper prostate differentiation
Authors: Le Magnen Clementine , Dutta Aditya , Mitrofanova Antonina , Califano Andrea , Abate-Shen Cory 
Published: July 2016

Abstract
Maintenance of cell differentiation is tightly coordinated by specific gene expression programs, which are often deregulated during tumorigenesis. While the homeodomain-containing transcription factor, NKX3.1, plays essential roles in both prostate differentiation and prostate cancer, the mechanisms governing these events are still unclear. Here, we aim to elucidate detailed mechanisms governing Nkx3.1-driven prostate epithelial differentiation and explain how deregulation of such can lead to prostate tumorigenesis.
Using an Nkx3.1 mutant mouse model, we find that loss-of-function of Nkx3.1 in the prostate results in the down-regulation of genes associated with prostate differentiation as well as the up-regulation of genes that are not normally expressed in prostate. Interestingly, these mice also develop pre-malignant lesions resembling prostatic intraepithelial neoplasia (PIN). Conversely, gain of function of Nkx3.1 in a fully differentiated non-prostate epithelium is sufficient to induce prostate differentiation in renal grafts in vivo. Using a DNA binding mutant, we show that these activities are mediated via NKX3.1 homeodomain in vitro and in vivo. Exploiting mass spectrometry to identify NKX3.1-interacting proteins, we find that NKX3.1 interacts with the histone methyltransferase G9a and that this interaction is required for induction of prostate differentiation in vitro and in vivo. Finally, we show that these NKX3.1-driven activities are mediated, at least in part, by regulation of target genes such as the male-specific factor UTY (KDM6c).
We propose that the NKX3.1-G9a-UTY network is essential for proper prostate differentiation whereas disruption of these activities predisposes to cancer.
Citation Format: Clementine Le Magnen, Aditya Dutta, Antonina Mitrofanova, Andrea Califano, Cory Abate-Shen. Identification of an NKX3.1-G9a-UTY regulatory network that controls proper prostate differentiation. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2888.
Abstract 2893: PARP-1 regulates cell cycle by downregulating E2F-1 transcriptional activity in vitro and in vivo
Authors: Iglesias Pablo , Seoane Marcos , Castro-Piedras Isabel , Arce Victor M. , Costoya Jose A. 
Published: July 2016

Abstract
Although PARP-1 has been traditionally related to DNA repair, in the last years an increasing number of studies have linked this polymerase to other cellular processes such as metabolism and cell mitosis.
In this study we wanted to investigate the biological importance of the interaction between PARP-1 and the transcription factor E2F-1, and more specifically in scenarios where the activity, or hyperactivity, of E2F-1 is of critical importance such as embryonic development or oncogenesis. In this regard, we have found that the treatment either with enzymatic inhibitors of PARP-1 has an effect on the transcriptional activity of E2F-1 as well as the proliferative rate of treated cells. This effect is significantly increased with the treatment with gossypol, a specific inhibitor of PARP-1 protein-protein interactions occurring through the BRCT domain, as in the case of E2F-1. This effect is also observed in vivo since the severity of histological malformations in Rb-/- embryos is significantly reduced in Parp-1-/- Rb-/- embryos, which phenotype closely resembles that of E2f-1-/- Rb-/- mice. Finally, we also found that the deletion or inhibition of PARP-1 in an animal model of gliomagenesis helps the cell to block oncogenic stimuli derived from E2F-1 hyperactivity, by reactivating critical signalling pathways involved in oncogene-induced senescence.
In summary, the importance of the relationship between PARP-1 and E2F-1 in different biological contexts leads us to believe that the search for ways of altering or disrupting this interaction could be a novel strategy for the development of molecules of therapeutic potential.
Citation Format: Pablo Iglesias, Marcos Seoane, Isabel Castro-Piedras, Victor M. Arce, Jose A. Costoya. PARP-1 regulates cell cycle by downregulating E2F-1 transcriptional activity in vitro and in vivo. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2893.
Abstract 29: MEK and PI3K signaling cooperate through mTORC1/2 to promote PIK3CA mutant melanoma cell proliferation
Authors: Silva Jillian M. , Deuker Marian M. , Baguley Bruce C. , McMahon Martin 
Published: July 2016

Abstract
Oncogenic transformation of mutationally activated BRAF or NRAS melanocytes often requires the cooperation of genetic aberrations in the phosphoinositide 3-kinase (PI3K) pathway to promote melanomagenesis. Activating point mutations in the p110α catalytic subunit of PI3K are detected at a low frequency in both BRAF and NRAS mutant melanomas, yet the principle mechanism of this cooperation remains elusive. Thus, using BRAFV600E/PIK3CAH1047R, NRASQ61H/PIK3CAH1047R, and PIK3CAE545K mutant melanoma cells derived from metastatic melanoma patients treated with pathway-targeted inhibitors, we examined the contribution of mutational activation of PIK3CA to melanoma maintenance and signaling and the consequential response of these PIK3CA mutant cells to α-specific PI3K inhibition. Combined MEK and isoform-selective PI3K inhibition elicited more potent anti-proliferative effects and greater suppression of S-phase progression of the cell cycle compared to single-agent inhibition of either pathway. Analysis of signaling downstream of MEK or PI3K revealed that these pathways cooperated to regulate PIK3CA cell proliferation through mTORC1-mediated effects on ribosomal protein S6 and 4E-BP1 phosphorylation in an AKT-dependent manner. Despite the profound anti-proliferative and biochemical effects of α-specific or PI3Kβ-sparing class I PI3K inhibition in vitro, these agents elicited largely cytostatic effects on PIK3CA xenograft tumors. However, combined inhibition of PI3Kβ-sparing class I PI3K and MEK did significantly cooperate to reduce tumor growth compared to the corresponding monotherapies. Furthermore, this study provides a biochemical mechanism to explain how mTORC1/2 moderates the cooperation of MEK and PI3K signaling for the maintenance of PIK3CA mutant melanoma cell proliferation.
Citation Format: Jillian M. Silva, Marian M. Deuker, Bruce C. Baguley, Martin McMahon. MEK and PI3K signaling cooperate through mTORC1/2 to promote PIK3CA mutant melanoma cell proliferation. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 29.
Abstract 2906: Targeting FoxA1 in estrogen receptor-positive breast cancer: biological characterization of kinase regulators
Authors: Johnston Simon J. , Holmes Kelly A. , Carroll Jason S. 
Published: July 2016

Abstract
Estrogen receptor (ER) is the driving and defining transcription factor in 75% of breast cancers and is directly inhibited by targeted therapies such as tamoxifen. DNA interactions and transcriptional potential of ER depend on the pioneer factor, FoxA1, which thereby plays an essential role in determining tumour growth and progression - even when resistance to existing drugs has developed. The aim of this study is to characterize kinase regulators of FoxA1 function in order to identify druggable targets for the indirect inhibition of ER.
To identify kinase regulators in ER+ breast cancer, primary screening of multiple cell lines was performed using an siRNA library of the human kinome. After secondary screening of ER+ specific growth-regulatory kinases using a stable luciferase reporter of FoxA1 activation, 50 putative kinase regulators of FoxA1 were identified. These were cross-referenced with kinase inhibitors of FoxA1 activation discovered via a separate cell-based compound screen and competitive-binding kinase displacement assay.
This two-pronged screening approach revealed 6 common putative FoxA1-regulatory kinase enzymes. These were characterized by chromatin immunoprecipitation (ChIP) of FoxA1 and ER with quantitative PCR of archetypal ER enhancers, 48 hours after siRNA knockdown of the kinase. This revealed 3 kinases whose inhibition prevented FoxA1 and ER from accessing the chromatin, and 1 kinase that had the opposite effect.
Mass spectrometry-based proteomic analysis of endogenous FoxA1-protein interactors using ChIP is underway to assess the change in FoxA1 co-factors following inhibition of these 4 candidate kinases. We used a proteomic purification method called RIME which permits analysis of phosphorylation events on FoxA1. We are currently assessing whether silencing of specific kinases influences phosphorylation of the putative substrate, FoxA1.
In summary, the identified kinases demonstrate promising FoxA1 specificity, and may provide druggable targets for the inhibition of ER via FoxA1. This study has potential clinical value for patients with tumours that have become resistant to existing ER-targeted therapies.
Citation Format: Simon J. Johnston, Kelly A. Holmes, Jason S. Carroll. Targeting FoxA1 in estrogen receptor-positive breast cancer: biological characterization of kinase regulators. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2906.
Abstract 2907: Eugenol potentiates the effect of cisplatin on cancer stem-like cells through targeting the NF-κB pathway
Authors: Islam Syed S. , Ibtehaj Al-Sharif , Ahlam Sultan , Aboussekhra Abdelilah 
Published: July 2016

Abstract
Triple-negative subtype of breast cancer (TNBC) contains exclusively tumorigenic and often endowed with self-renewing and resistance to cytotoxic chemotherapy, such as, paclitaxel resulting in relative increases in CSCs phenotype. Signaling through NF-kB may be essential for the CSCs self-renewal and could present potential target for novel treatment in breast cancer patients. We explored the possible involvement of NF-kB pathway that contribute to the functions and maintenance of breast CSCs and targeting this pathway by cisplatin combining with a natural product eugenol both in vitro and in vivo, using estrogen dependent (MCF-7) and independent (MDA-MB-231, MDA-MB-468 and BT-20) cell lines and xenografted both subcutaneous and orthotopic (fat pad) sites in nude mice. Chromatin immunoprecipitation (ChIP) assay was utilized to assess the NF-kB associated DNA binding capacity in promoter region. Surprisingly, neither cisplatin nor eugenol was capable of complete diminishing the CSCs populations. Cisplatin alone administration partially diminished apoptosis, mammospheres formation, aldehyde dehydrogenase 1 (ALDH1) activity, invasion and growth on nude mice. We observed cisplatin-induced activation of NF-kB associated with survival and regrowth of mamospheres. For effective elimination of CSCs phenotype by cisplatin, we cotreated cells with eugenol. Combination of eugenol and cisplatin significantly eradicated cisplatin induced NF-kB DNA binding capability assed by EMSA and ChIP assays, which was associated with abrogated apoptosis, mammospheres formation, ALDH1 activity and invasion. In vivo, combination therapy reduced the tumor size in synergistic manner. This was possibly due to induction of apoptosis, inhibition of proliferation, angiogenesis and downregulation of cisplatin-induced expression of proteins of NF-kB target genes. Although treatment of mammospheres by cisplatin partially induced the CSCs population through interleukin (IL)-6 pathway, however, only coadministration of eugenol and cisplatin reduced the numbers of CSCs to virtually undeletable levels in vitro and in vivo. Our data suggest that eugenol may be well suited to increase targeting of breast CSCs by cisplatin.
Citation Format: Syed S. Islam, Al-Sharif Ibtehaj, Sultan Ahlam, Abdelilah Aboussekhra. Eugenol potentiates the effect of cisplatin on cancer stem-like cells through targeting the NF-κB pathway. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2907.
Abstract 2924: Metastasis-associated protein 1 induces tamoxifen resistance in MCF7 breast cancer cells
Authors: Lee Min-Ho , Koh Dahae , Lee Mi-Ock 
Published: July 2016

Abstract
Tamoxifen is most commonly used to treat estrogen receptor-alpha positive breast cancer, but its therapeutic benefit is limited by the development of drug resistance. Metastasis associated protein 1 (MTA1) is a cancer progression-related gene and has been reported to be overexpressed in a variety of human cancers including breast cancer. Here, we showed that transient overexpression of MTA1 in MCF7 breast cancer cells results in tamoxifen resistance, whereas si-RNA mediated knockdown of MTA1 was more susceptible to tamoxifen-induced growth inhibition. Moreover, stable overexpression of MTA1 in MCF7 cells promoted cell proliferation and reduced tamoxifen sensitivity. To explore the mechanisms of MTA1-mediate tamoxifen resistance, we used microarray analysis to profile the gene expression patterns of MTA1 overexpress MCF7 stable cells after tamoxifen treatment. From microarray data analysis, 538 genes were selected as associated with MTA1-mediated tamoxifen resistance (P &lt; 0.05, LPE test; cutoff ≥ 1.5-fold). The Database for Annotation, Visualization and Integrated Discovery (DAVID) analysis revealed that the predominant biological processes associated with these genes are M phase, negative regulation of cell proliferation, mitosis and M phase of mitotic cell cycle. Further, we found that cell-cycle regulator Cyclin D1 and cyclin B1 protein levels were increased in MTA1 overexpression MCF7 stable cells. Analyses of publicly available patient data sets indicated that MTA1 levels are higher in patients after endocrine therapy failure (recurrence), compared to those of responders (non-recurrence). These results suggest that MTA1 may contributed tamoxifen resistance through the regulation of cell cycle components.
Citation Format: Min-Ho Lee, Dahae Koh, Mi-Ock Lee. Metastasis-associated protein 1 induces tamoxifen resistance in MCF7 breast cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2924.