bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 4611: Interrogation of PI3K signaling via multiplex detection of differential phosphorylation of specific Akt isoforms
Authors: Saporita Anthony J. , Schluter Melissa , MacIvor Debra , Mistry Jehangir , Hwang Joseph 
Published: July 2016

Abstract
The serine/threonine protein kinase Akt is a key node in the PI3K pathway, one of the primary signaling cascades hyperactivated in human cancer. Emerging evidence demonstrates that the three Akt isoforms (Akt1, Akt2, and Akt3) may have unique, isoform-specific roles in key cellular processes such as differentiation and proliferation. We have developed 2-plex assays for each of the Akt isoforms in order to measure the relative levels of phospho- and total Akt1, Akt2, and Akt3. Differential regulation of Akt isoforms was characterized in multiple human cancer cell lines, including SH-SY5Y neuroblastoma cells and MCF-7 breast cancer cells. SH-SY5Y cells were used to study Akt phosphorylation in the context of differentiation. Briefly, SH-SY5Y cells were treated with retinoic acid (RA) for 3 days to induce neuronal differentiation before cells were collected, lysed, and evaluated by Luminex assay. RA-induced differentiation of SH-SY5Y cells stimulated phosphorylation of all three Akt isoforms, with Akt2 displaying the greatest induction. Multi-pathway analysis demonstrated co-induction of phospho-JNK in the RA-treated SH-SY5Y cells, consistent with the role of JNK in RA-mediated differentiation. To study differential regulation of the Akt isoforms in response to growth-stimulatory and growth-inhibitory signals, we used MCF-7 cells. In contrast to SH-SY5Y cells which express all three isoforms, MCF-7 cells only expressed Akt1 and Akt2. Serum-starved MCF-7 cells were cultured in the presence or absence of the PI3K inhibitor LY294002 prior to stimulation with insulin growth factor (IGF). Akt1 showed a greater induction of phosphorylation in response to IGF relative to Akt2. Similarly, whereas LY294002 pre-treatment reduced phospho-Akt1 to baseline levels, it only partially inhibited the IGF-dependent induction of phospho-Akt2. This suggests that Akt1 may be more sensitive to PI3K inhibition than Akt2 in certain human breast cancer cells. Collectively, our results demonstrate that Akt1, Akt2, and Akt3 are differentially regulated in human cancer cells at both the level of phosphorylation and of total protein expression.
Citation Format: Anthony J. Saporita, Melissa Schluter, Debra MacIvor, Jehangir Mistry, Joseph Hwang. Interrogation of PI3K signaling via multiplex detection of differential phosphorylation of specific Akt isoforms. [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 4611.
Abstract 4612: In breast cancer cells IGF-I induces upregulation of DDR1 by suppressing miR-199a-5p via the PI3K/Akt pathway
Authors: Palladino Chiara , Matà Roberta , Nicolosi Maria Luisa , Lo Presti Anna Rita , Malaguarnera Roberta , Ragusa Marco , Sciortino Daniela , Morrione Andrea , Maggiolini Marcello , Vella Veronica , Belfiore Antonino 
Published: July 2016

Abstract
Discoidin Domain Receptor 1 (DDR1) is a collagen receptor tyrosine-kinase that is implicated in tumor progression by contributing to epithelial mesenchymal transition (EMT) and by enhancing tumor cell migration and invasion.
We previously demonstrated that, in breast cancer cells, DDR1 functionally cross-talks with IGF-I receptor (IGF-IR), by affecting IGF-IR expression and trafficking. In these cells, DDR1 was able to enhance the stimulatory effects of IGF-I on mitogenesis and invasion suggesting that the DDR1-IGF-IR cross-talk may play a role in cancer progression.
Herein, we evaluated whether IGF-I may in turn affect DDR1 expression. Indeed, we demonstrated that in breast cancer cells (MCF-7 and MDA-MB-231), IGF-I was able to upregulate DDR1 protein expression in a time and dose dependent manner. In contrast, DDR1 mRNA levels showed non-significant changes after stimulation with IGF-I.
Moreover, we found that DDR1 protein upregulation requires the activation of the PI3K/Akt pathway, while the Erk1/2, the p70/mTOR and the PKC pathways are not involved.
Indeed, IGF-I induced DDR1 protein upregulation through a post-trascriptional mechanism involving miR-199a-5p suppression via Akt. We also found that autocrine IGF-II, induced by stable IGF-II cDNA transfection, is also able to elicit significant DDR1 upregulation in breast cancer cells. Similar effects were induced by IGF-II secreted by human cancer associated fibroblasts.
Finally, we showed that miR-199a-5p transfection in breast cancer cells, decreased DDR1 expression and affected the response to IGF-I in terms of intracellular signaling through the PI3K/Akt and Erk1/2 pathways, and biological effects such as cell proliferation and migration.
These results demonstrate that the protumoral effects of IGF-I include downregulation of miR-199a-5p and consequent upregulation of DDR1 protein. Both these molecules may represent important targets for breast cancers with overactivation of the IGF-IR axis.
Citation Format: Chiara Palladino, Roberta Matà, Maria Luisa Nicolosi, Anna Rita Lo Presti, Roberta Malaguarnera, Marco Ragusa, Daniela Sciortino, Andrea Morrione, Marcello Maggiolini, Veronica Vella, Antonino Belfiore. In breast cancer cells IGF-I induces upregulation of DDR1 by suppressing miR-199a-5p via the PI3K/Akt 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 4612.
Abstract 4613: SMYD3-mediated lysine methylation is critical for the activation of AKT1 in human cancer
Authors: Yoshioka Yuichiro , Nakamura Yusuke , Hamamoto Ryuji 
Published: July 2016

Abstract
v-Akt Murine Thymoma Viral Oncogene Homolog 1 (AKT1), a serine/threonine-protein kinase also known as protein kinase B Alpha (PKB Alpha), is a key mediator of a signaling pathway that governs various cellular processes regulating cell growth, survival, glucose metabolism, genome stability and neovascularization. It is known that dysregulation of AKT1 activity is one of the critical factors for the development and/or progression of a variety of human cancers. Posttranslational modifications of AKT1, including phosphorylation, ubiquitination and glycosylation, are well-analyzed, and it is known that the phosphorylation status of AKT1 is strongly correlated with its oncogenic activity. However, biological functions of methylation on AKT1 have never been analyzed so far. In the present study, we demonstrated that the protein lysine methyltrasnferase SMYD3 methylates lysine 14 in the PH domain of AKT1, which is known to play a critical role in the regulation of AKT1 activity through binding to phosphatidylinositol-3,4,5-triphosphate (PtdIns(3,4,5)P3) or phosphatidylinositol-3,4-bisphosphate (PtdIns(3,4)P2), in vitro and in vivo. Lysine 14-substituted AKT1 shows significantly lower levels of phosphorylation at threonine 308, which is the major indicator of AKT1 activity, than wild-type AKT1, and knockdown of SMYD3 as well as treatment with a SMYD3 inhibitor significantly attenuates this phosphorylation in cancer cells. Furthermore, substitution of lysine 14 diminishes the plasma membrane accumulation of AKT1, and cancer cells overexpressing lysine 14-substiuted AKT1 shows lower growth rate than those overexpressing wild-type AKT1. These results imply that SMYD3-mediated methylation of AKT1 at lysine 14 plays a central role in the oncogenic activity of AKT1. Although Phosphatidylinositide 3-kinase (PI3K)-dependent AKT1 phosphorylation by Pyruvate Dehydrogenase Kinase, Isozyme 1 (PDK1) and mTOR Complex 2 (mTORC2) has long been considered to be the primary mechanism accounting for AKT1 activation, these members are not sufficient enough to explain how AKT1 hyperactivation can occur in tumors with normal levels of PI3K/Phosphatase And Tensin Homolog (PTEN) activity. Our findings unveiled the novel mechanism of constitutive hyperphosphorylation on AKT1 in cancer cells, mediated by SMYD3-mediated methylation. The inhibition of this methylation pathway appears to be a promising strategy to develop anti-cancer drugs.
Citation Format: Yuichiro Yoshioka, Yusuke Nakamura, Ryuji Hamamoto. SMYD3-mediated lysine methylation is critical for the activation of AKT1 in human 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 4613.
Abstract 4622: Identification of p62/SQSTM1 as a component of non-canonical WNT VANGL2-JNK signaling in breast cancer
Authors: Borg Jean-Paul , Tania Puvirajesinghe , Bertucci François , Birnbaum Daniel , Jain Ashish , Johansen Terje , Scerbo Pierluigi , Kodjabachian Laurent 
Published: July 2016

Abstract
Planar cell polarity (PCP), an evolutionarily conserved developmental process originally described in Drosophila melanogaster, is essential to the control of tissue morphogenesis and development of polarized structures in metazoans. Its importance in human diseases is best demonstrated in polycystic kidney disease, hearing loss, Bardet Biedl syndrome, neural tube closure defects and cancer. PCP involves a set of evolutionarily conserved PCP genes encoding WNT ligands, transmembrane (vangl2, frizzled, fat, dachsous) and cytoplasmic (scribble, prickle, dishevelled, diego) molecules triggering a genetically well-defined non-canonical WNT-JNK pathway. Recent work has linked defects of this pathway to breast cancer aggressiveness and proposed non-canonical WNT/PCP signaling as a therapeutic target. Here we show that the archetypal non-canonical WNT/PCP protein VANGL2 is overexpressed in basal breast cancers, associated with poor prognosis and implicated in tumor growth. We identify the scaffold p62/SQSTM1 protein as a novel VANGL2-binding partner and show its key role in an evolutionarily conserved VANGL2-p62/SQSTM1-JNK pathway in breast cancer cells and in Xenopus. This proliferative signaling cascade is upregulated in breast cancer patients with shorter survival, and can be inactivated in patient-derived xenograft cells by inhibition of the JNK pathway or by disruption of the VANGL2-p62/SQSTM1 interaction. VANGL2-JNK signaling is thus a potential target for breast cancer therapy.
Puvirajesinghe T.M., et al. Identification of p62/SQSTM1 as a component of non-canonical Wnt VANGL2-JNK signaling in breast cancer. Nature Communications, in press. Sebbagh M. and Borg J.-P. Insight into Planar Cell Polarity. (2014) Invited review in Experimental Cell Research, 328:284-295. Belotti E., et al. The human PDZome: a gateway to PDZ mediated functions. (2013) Mol Cell Proteomics, 12: 2587-603.
Citation Format: Jean-Paul Borg, Puvirajesinghe Tania, François Bertucci, Daniel Birnbaum, Ashish Jain, Terje Johansen, Pierluigi Scerbo, Laurent Kodjabachian. Identification of p62/SQSTM1 as a component of non-canonical WNT VANGL2-JNK signaling in breast 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 4622.
Abstract 4628: The RSK inhibitor SL0101 impairs the proliferation of glioblastoma cell lines
Authors: Roffe Martín , Lupinacci Fernanda C. , Soares Luana C. , Hajj Glaucia N. , Martins Vilma R. 
Published: July 2016

Abstract
Glioblastoma (GBM) is the most common and lethal type of brain tumor. The most frequently altered signaling pathway in this tumor is the RTKs-PI3K-Akt-mTORC1 (88% of cases). However, clinical trials for GBM using inhibitors of this pathway exhibited poor clinical responses. One of the main responsibles for this resistance is the compensatory activation of the Ras-ERK1/2 pathway. In fact, GBMs can also present alterations in the Ras-ERK1/2 pathway, such as mutation of NF1 in 18% of the cases. RSK is a direct target of ERK1/2 and has been shown to regulate important functions in different types of tumors, such as prostate and breast. RSK is a family of kinases comprised by four highly-homologous isoforms in humans (RSK1-4) and nothing is known about their functions in GBMs. Here we show that RSK1 levels are highly variable between cells, the levels of RSK2 are less variable, and RSK3 and RSK4 were not detected. To gain insight into the function of RSK, we studied the effects of the RSK inhibitor, SL0101, on the proliferation of four different GBM cell lines (LN18, LN229, U87MG and A172). A suboptimal concentration of SL0101 (50 μM) was able to inhibit basal and EGF-stimulated proliferation, and it was more potent than 100 nM rapamycin in some of the cells. In 3 of the cell lines, SL0101 inhibited serum-stimulated proliferation, and in 2 of them, it was more potent than rapamycin. We have previously shown that SL0101 can inhibit mTORC1 signaling in an ERK1/2-RSK independent manner. However, SL0101 showed a synergistic interaction with rapamycin in all of the cell lines, which suggests that other effects besides RSK-mTORC1 inhibition might be involved in the effect of SL0101. This was further suggested by the modest synergistic interaction between rapamycin and the RSK inhibitor, fmk. Altogether, these results indicate that SL0101 is a potent inhibitor of proliferation in a manner not related with the RSK1 status of GBM cells. Further studies to define the molecular mechanism of the effects of SL0101 are necessary to understand which pathways are indeed modulated.
Citation Format: Martín Roffe, Fernanda C. Lupinacci, Luana C. Soares, Glaucia N. Hajj, Vilma R. Martins. The RSK inhibitor SL0101 impairs the proliferation of glioblastoma cell lines. [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 4628.
Abstract 4631: SCFFbxo7 ubiquitin ligase targets cereblon to limit the anti-myeloma activity of IMiDs
Authors: Liu Jiye , Zhou Wenrong , Feng Yan , Song Tianyu , Gao Shaobing , Wu Junfeng , Peng Zhenggang , Cang Yong 
Published: July 2016

Abstract
Multiple myeloma (MM) patients have witnessed significantly improved survival after the approved treatment with the proteasome inhibitor bortezomib and immunomodulatory drugs (IMiDs) including thalidomide and its derivatives lenalidomide and pomalidomide. IMiDs directly bind cereblon (CRBN), an adaptor of the Cul4-DDB1 (CRL4) ubiquitin ligase, and activate CRL4CRBN to target B cell-specific transcription factors IKZF1 and IKZF3 for ubiquitination. IKZF1 and IKZF3 are essential for MM cell survival and their proteasomal degradation induced by IMiDs provides insights into how these drugs work. Paradoxically, IMiDs achieve better clinical response in MM patients when combined with bortezomib, which blocks IKZF1 and IKZF3 turnover and would in principle counteract IMiDs therapy. We performed a CRISPR-based genome-wide knockout screening for regulators of pomalidomide sensitivity in MM cells, and found that CRBN is inherently unstable and its level is controlled by the COP9 signalosome (CSN) to sustain IMiDs cytotoxicity. When unbound to CRL4, CRBN is recruited by the F-box protein Fbxo7 to the Cul1-Skp1 (SCF) ubiquitin ligase for ubiquitination and degradation, a process suppressed by CSN-mediated de-neddylation of Cul1. Deletion of SCFFbxo7 components, or treatment with bortezomib or neddylation inhibitor MLN4924 stabilizes CRBN, and IMiDs further promote the loading of CRBN to CRL4 by inhibiting SCFFbxo7-targeted CRBN degradation, leading to enhanced turnover of IKZF1 and IKZF3 in MM cells and synergistic inhibition of MM cell proliferation. Our findings unravel a dual role of IMiDs in activating CRL4CRBN E3 ligase in MM cells and provide a framework to select patients most susceptible to bortezomib and IMiDs combination therapy.
Citation Format: Jiye Liu, Wenrong Zhou, Yan Feng, Tianyu Song, Shaobing Gao, Junfeng Wu, Zhenggang Peng, Yong Cang. SCFFbxo7 ubiquitin ligase targets cereblon to limit the anti-myeloma activity of IMiDs. [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 4631.
Abstract 4638: Targeted therapy of precancerous fields in the mucosal linings of the head and neck
Authors: de Boer D Vicky , Martens-de Kemp Sanne R. , Buijze Marijke , Stigter-van Walsum Marijke , Bloemena Elisabeth , Leemans C René , Braakhuis Boudewijn J.M. , Brakenhoff Ruud H. 
Published: July 2016

Abstract
Primary head and neck squamous cell carcinomas (HNSCC) and local relapses develop in preneoplastic fields in the mucosal linings of the upper aerodigestive tract. These fields are characterized by tumor-associated genetic changes, show frequently dysplastic features and are occasionally macroscopically visible as lesions. Currently, there are no adequate treatment options for these fields to prevent tumor development. To develop a targeted therapeutic approach we established four unique preneoplastic cell lines, derived from fields adjacent to HNSCCs. Next, we performed a screen with a selective panel of small interfering RNAs (siRNAs) that are lethal for HNSCC cells, to identify genes essential for survival of preneoplastic cells and not for normal cells. One of these selective essential genes was Polo-like kinase 1 (PLK1). Inhibition of PLK1, both with siRNAs as well as small molecule inhibitors, caused cell death of preneoplastic and HNSCC tumor cells, while primary fibroblasts and keratinocytes were hardly affected. Targeting PLK1 caused a strong G2/M cell cycle arrest in preneoplastic cells accompanied by formation of monopolar spindles during mitosis. Hence, PLK1 is a promising therapeutic target for chemopreventive eradication of preneoplastic fields in patients at high risk of developing HNSCC and local relapses.
Citation Format: D Vicky de Boer, Sanne R. Martens-de Kemp, Marijke Buijze, Marijke Stigter-van Walsum, Elisabeth Bloemena, C René Leemans, Boudewijn J.M. Braakhuis, Ruud H. Brakenhoff. Targeted therapy of precancerous fields in the mucosal linings of the head and neck. [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 4638.
Abstract 4644: Inhibition of the androgen receptor at two drug-targetable sites on the DNA-binding domain protein surface
Authors: Dalal Kush , Sharma Aishwariya , Roshan-Moniri Mani , Borgmann Hendrik , Lallous Nada , Awrey Shannon , Li Huifang , Ban Fuqiang , LeBlanc Eric , Cherkasov Artem , Rennie Paul S. 
Published: July 2016

Abstract
The androgen receptor (AR) is a hormone inducible transcription factor that continues to be an important drug-target to prevent or slow the progression of prostate cancer. Current small molecule inhibitors, such as Enzalutamide (anti-androgens), compete with naturally occurring steroids that bind to the hormone binding pocket of the AR ligand binding domain (LBD). In advanced or castration resistant prostate cancer (CRPC), mutations in the LBD confer drug-resistance by converting anti-androgens into agonists, prompting research to develop small molecule inhibitors that target different sites on the AR protein surface. Recently, we characterized a set of small molecules that could interact with the DNA binding domain (DBD) of the AR and block its transcriptional activity. Here, we extend the pioneering observations by clarifying the mechanism of two classes of compounds that either block AR-chromatin interactions or reduce AR-dimerization in the cell nucleus. Compound efficacy is demonstrated across multiple prostate cancer cells lines, including enzalutamide resistant forms, with respect to AR transactivation, cell viability and expression of downstream genes. We also characterize the pharmacological properties of the lead compound and its effects on tumour xenografts in mice. Collectively, these results lay the foundation for the development of alternative prostate cancer drugs that interfere with the biochemical function of the activated, nuclear localized AR.
Citation Format: Kush Dalal, Aishwariya Sharma, Mani Roshan-Moniri, Hendrik Borgmann, Nada Lallous, Shannon Awrey, Huifang Li, Fuqiang Ban, Eric LeBlanc, Artem Cherkasov, Paul S. Rennie. Inhibition of the androgen receptor at two drug-targetable sites on the DNA-binding domain protein surface. [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 4644.
Abstract 4660: Inhibition of p38 enhances ERK inhibitor efficacy in pancreatic ductal adenocarcinoma
Authors: Ryan Meagan B. , Bryant Kirsten L. , Hayes Tikvah K. , Kher Swapnil , Wood Kris C. , Samatar Ahmed A. , Cox Adrienne D. , Der Channing J. 
Published: July 2016

Abstract
Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer deaths in the United States, with a poor prognosis and limited treatment options. Oncogenic mutation of KRAS in greater than 90% of PDAC leads to aberrant activation of multiple effector pathways including the extra cellular related kinase (ERK)/mitogen activated protein kinase (MAPK) cascade. Hyperactivation of the ERK MAPK cascade has been correlated with poorer prognosis in PDAC patients. We recently showed that direct pharmacological inhibition of ERK1/2 kinases with the ERK1/2-selective inhibitor SCH772984 inhibits the growth of PDAC cell lines both in vitro and in vivo. However, much like the response to ERK/MAPK pathway inhibitors acting at upstream nodes RAF or MEK, resistance to direct inhibition at the level of ERK will also inevitably arise. We performed a novel gain-of-function “Cancer Toolkit” (CTK) genetic screen to identify mechanisms of resistance to the ERK inhibitor SCH772984 in a panel of KRAS-mutant PDAC cell lines. Our CTK screen revealed that expression of either MAPK14 (p38α) or its upstream activator MKK6 could cause resistance to this and other ERK inhibitors. Because we identified activation of the p38 pathway as a mechanism of ERK inhibitor resistance, we tested whether inhibition of p38 would enhance sensitivity to SCH772984. We observed a &gt;2 fold shift to a lower GI50 of SCH772984 upon cotreatment of a panel of established and patient-derived xenograft (PDX) PDAC cell lines with SCH772984 and the clinical candidate p38 inhibitor LY2228820. Consistent with this, we found that SCH772984 induced p38 signaling, marked by phosphorylation of the downstream substrate HSP27, and that combination treatment of SCH772984 and LY2228820 both reversed p38 pathway activation and enhanced PARP cleavage. Results of in vivo testing of the combination treatment as well as the mechanistic basis for p38-driven resistance will be reported. We propose that p38 is a mechanism of resistance to ERK inhibition in PDAC and that p38 inhibitors such as LY2228820 can overcome that resistance to enhance ERK inhibitor efficacy.
Citation Format: Meagan B. Ryan, Kirsten L. Bryant, Tikvah K. Hayes, Swapnil Kher, Kris C. Wood, Ahmed A. Samatar, Adrienne D. Cox, Channing J. Der. Inhibition of p38 enhances ERK inhibitor efficacy in pancreatic ductal adenocarcinoma. [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 4660.