bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3149: Identification of genes associated with the cisplatin resistance in cervical cancer cells expressing E545K mutation
Authors: Arjumand Wani , Jette Nicholas , McIntyre Jb , Ghatage Prafull , Doll Corinne M. , Lees-Miller Susan P.
Published: July 2017

The phosphatidylinositol-3 kinase (PI3K)/AKT/ mTOR signaling pathway is activated in several human cancers and activation is frequently mediated by “hotspot” mutations including E542K, E545K and H1047R in the PIK3CA gene. Approximately 30% of cervical cancer patients have the PIK3CA-E545K mutation. Cisplatin with radiotherapy (RT) is the standard treatment of cervical cancer world-wide, used in both the radical and post-operative adjuvant settings. However, details of the molecular mechanisms responsible for cisplatin resistance remain unclear. We previously reported PIK3CA mutation in patients with earlier stage (IB/II) cervical cancer was associated with poor survival (McIntyre et al. Gynecol Oncol. 2013, PMID:23266353), and in our recent study we observed that PIK3CA-E545K mutation renders cervical cancer cells more resistant to cisplatin or cisplatin plus RT and results in a more migratory phenotype than isogenic cell lines with wild type-PIK3CA. Moreover, these phenotypes are reversed by the PI3K inhibitor GDC-0941/Pictilisib (Wani et al. Oncotarget. 2016, PMID:27489350). The aim of the present study is to identify the expression of genes related to cisplatin resistance in cervical cancer cells engineered to express PIK3CA-E545K. Microarray analysis identified 161 genes that were up-regulated and 189 that were down-regulated in the cervical cancer cells stably expressing PIK3CA-E545K, some of which are involved in well-characterized mechanisms that could be relevant to cisplatin resistance. We are currently validating some of those genes by Real-time PCR that will help us to determine the mechanism of PIK3CA-E545K induced cisplatin resistance and enhanced migration in cervical cancer cells expressing PIK3CA-E545K and extending our in vitro findings to animal models. Together, our data will provide a useful basis for screening candidate targets for risk stratification and provide valuable information for potential targeted intervention in patients whose tumors harbor cisplatin-resistant molecular characteristics.

Citation Format: Wani Arjumand, Nicholas Jette, Jb McIntyre, Prafull Ghatage, Corinne M. Doll, Susan P. Lees-Miller. Identification of genes associated with the cisplatin resistance in cervical cancer cells expressing E545K mutation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3149. doi:10.1158/1538-7445.AM2017-3149
Abstract 315: S100B regulates IL-6 signaling via the p90 ribosomal S6 kinase (RSK) in malignant melanoma
Authors: Alasady Milad J. , Adipietro Kaylin A. , Pierce Adam D. , Wilder Paul T. , Hartman Kira G. , Weber David J. , Hay Nissim
Published: July 2017

S100B is a tumor marker that is highly elevated during the progression of malignant melanoma. However, the function of S100B in the progression of melanoma is not well understood. Here we propose a regulatory mechanism that defines interplay between S100B, Interleukin-6 (IL-6), STAT3, and CREB. First, we show that S100B inhibits IL-6 mRNA and protein levels, and that silencing S100B in melanoma cell lines induces the expression and secretion of IL-6. Consistent with this result, STAT3 phosphorylation and its activation occur upon S100B ablation and IL-6 production. Our data suggest that S100B exerts its effect on the IL-6 pathway via p90 ribosomal S6 kinase (RSK), leading to activation of transcription factor CREB. Elevated S100B in melanoma cells were shown to bind directly to RSK, sterically block its phosphorylation (at Thr573) and sequester RSK in the cytoplasm (Hartman et al., 2014). Silencing of S100B enables RSK nuclear translocation, which in turn elevates CREB phosphorylation and its transcriptional activity in the nucleus to induce IL-6 expression, which is consistent with these newer observations. Because IL-6 can inhibit the proliferation of melanocytes and early stage melanoma cells, we propose that the suppression of IL-6 by elevated S100B may be a mechanism for cancer cells to circumvent the inhibitory effect of IL-6 at early stages of melanoma. Additionally, the suppression of IL-6 by elevated S100B may also curb local immune response(s), which otherwise would be elevated by the secreted IL-6.

Note: This abstract was not presented at the meeting.

Citation Format: Milad J. Alasady, Kaylin A. Adipietro, Adam D. Pierce, Paul T. Wilder, Kira G. Hartman, David J. Weber, Nissim Hay. S100B regulates IL-6 signaling via the p90 ribosomal S6 kinase (RSK) in malignant melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 315. doi:10.1158/1538-7445.AM2017-315
Abstract 3151: Loss of Axin1 drives acquired resistance to WNT pathway blockade in colorectal cancer cells carrying RSPO3 fusions
Authors: Picco Gabriele , Petti Consalvo , Centonze Alessia , Torchiaro Erica , Bardelli Alberto , Medico Enzo
Published: July 2017

In colorectal cancer (CRC), WNT pathway activation by genetic rearrangements of RSPO3 is emerging as a promising target. However, its low prevalence severely limits availability of preclinical models for in-depth characterization. Using a pipeline designed to suppress stroma-derived signal, we find that RSPO3 “outlier” expression in CRC samples highlights translocation and fusion transcript expression. Outlier search in 151 CRC cell lines identified VACO6 and SNU1411cells as carriers of, respectively, a canonical PTPRK(e1)-RSPO3(e2) fusion and a novel PTPRK(e13)-RSPO3(e2) fusion. Both lines displayed marked in vitro and in vivo sensitivity to WNT blockade by the porcupine inhibitor LGK974, associated with transcriptional and morphological evidences of WNT pathway suppression. Long-term treatment of VACO6 cells with LGK974 led to the emergence of a resistant population carrying two frameshift deletions of the WNT pathway inhibitor AXIN1, with consequent protein loss. Suppression of AXIN1 in parental VACO6 cells by RNA interference conferred marked resistance to LGK974. These results provide the first mechanism of secondary resistance to WNT pathway inhibition.

Citation Format: Gabriele Picco, Consalvo Petti, Alessia Centonze, Erica Torchiaro, Alberto Bardelli, Enzo Medico. Loss of Axin1 drives acquired resistance to WNT pathway blockade in colorectal cancer cells carrying RSPO3 fusions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3151. doi:10.1158/1538-7445.AM2017-3151
Abstract 3158: In vivo acquired resistance to an emibetuzumab analogue in MET-amplified gastric xenografts can be overcome by a MET-targeting antibody mixture or PIK3CA/AKT/mTOR inhibition
Authors: Pollmann Sofie Ellebæk , Petricoin Emanuel Frank , Calvert Valerie , Rao Shruti , Boca Simina , Madhavan Subha , Horak Ivan David , Kjær Andreas , Kragh Michael , Poulsen Thomas Tuxen
Published: July 2017

Aberrant over-activation of MET receptor tyrosine kinase is involved in driving malignancies such as gastric and non-small cell lung cancer (NSCLC), and in the development of resistance to EGFR-targeting therapeutics. This has led to the development of several MET-targeting agents in the form of tyrosine kinase inhibitors (TKIs) and monoclonal antibodies (mAbs), many of which are in clinical development. However, resistance to MET-targeted agents is an emerging problem. This study aims to understand mechanisms underlying resistance development to an analogue of emibetuzumab, a mAb targeting MET. Upon long term in vivo treatment, emibetuzumab-resistant tumors and cell lines were generated, isolated, and characterized to investigate their acquired resistance mechanisms. Extensive reverse phase protein array and network analysis were used to characterize the proteomic profiles of three resistant cell lines, revealing three distinct resistance profiles, one involving activation of the PI3Kinase/AKT/mTOR pathway. We further show, how these resistance mechanisms can be overcome by treatment with other targeting therapeutics both in vitro and in vivo. Two of the models demonstrated in vivo sensitivity to Sym015, a novel mixture of two mAbs targeting non-overlapping epitopes of MET, partly due to ADCC, indicating that Sym015 can overcome acquired resistance to emibetuzumab. The third model demonstrated a marked increase in PI3Kinase/AKT/mTOR pathway activation. This activation translated into induced cancer cell and tumor growth, which could be inhibited by agents targeting PI3Kinase, AKT, or mTOR. This study thus points to treatment of patients with acquired resistance to single targeting MET mAbs with PI3Kinase/AKT/mTOR-targeting agents or a MET-targeting antibody mixture such as Sym015.

Citation Format: Sofie Ellebæk Pollmann, Emanuel Frank Petricoin, Valerie Calvert, Shruti Rao, Simina Boca, Subha Madhavan, Ivan David Horak, Andreas Kjær, Michael Kragh, Thomas Tuxen Poulsen. In vivo acquired resistance to an emibetuzumab analogue in MET-amplified gastric xenografts can be overcome by a MET-targeting antibody mixture or PIK3CA/AKT/mTOR inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3158. doi:10.1158/1538-7445.AM2017-3158
Abstract 3159: Lysosomal membrane permeabilization as potential mediator of resistance in pancreatic neuroendocrine tumors
Authors: Wiedmer Tabea , Frank Rasmus M. , Tschan Mario P. , Perren Aurel , Marinoni Ilaria
Published: July 2017

Sunitinib, an anti-angiogenic tyrosine kinase inhibitor, is approved for treatment of pancreatic neuroendocrine tumors (pNETs). However, its efficacy is greatly limited due to resistance. Sunitinib is a lysosomotropic drug, thus accumulates in lysosomes, leading to their destabilization and to lysosomal membrane permeabilization (LMP), which in turn can lead to cell death. Autophagy might be activated for clearance of damaged lysosomes, thus promote survival and act as a mechanism of resistance. We found that the autophagy inhibitor chloroquine increases sunitinib efficacy in pNET cell lines and in a transgenic mouse model of pNETs. Interestingly, chloroquine is a lysosomotropic drug as well and the response towards sunitinib and chloroquine in pNET cell lines correlated with lysosome-associated membrane protein 2 (LAMP2) levels, which influence lysosome stability. We hypothesized that sunitinib and the combination with chloroquine induce LMP in pNETs and that LMP leads to activation of the transcription factor EB (TFEB), master regulator of genes involved in lysosomal biogenesis and autophagy, leading to therapy resistance. We found that LMP increased upon combined treatment of sunitinib and chloroquine compared to single treatment in pNET cell lines. Treatment of pNET cell lines with sunitinib or chloroquine led to activation of TFEB as assessed by nuclear/cytoplasmic fractionation and western blotting. Additionally, sunitinib significantly increased the expression of TFEB target genes, which were further upregulated upon combination with chloroquine. Interestingly, activation of TFEB and upregulation of TFEB target genes was more pronounced in the more resistant pNET cell line with respect to reduced viability and increased apoptosis. Our data indicate that sunitinib and chloroquine activate TFEB in pNET cell lines, leading to autophagy as a survival mechanism. Upon massive LMP or if autophagy is dysfunctional, cell death is induced. Based on our data, we suggest the combination of sunitinib and chloroquine as a treatment option for pNET patients and that TFEB could be an interesting therapeutic target in combination with lysosomotropic drugs.

Citation Format: Tabea Wiedmer, Rasmus M. Frank, Mario P. Tschan, Aurel Perren, Ilaria Marinoni. Lysosomal membrane permeabilization as potential mediator of resistance in pancreatic neuroendocrine tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3159. doi:10.1158/1538-7445.AM2017-3159
Abstract 3180: Chemotherapeutical agent triggers transient resistance of cancer cells by promoting ABCB1 intercellular transfer
Authors: Wang Xiaokun , Qiao Dongjuan , Chen Likun , Huang Liyan , Xu Meng , Chen Zhen , Wang Fang , Chen Zhesheng , Zeng Musheng , Fu Li-Wu
Published: July 2017

Multidrug resistance remains a major impediment to successful chemotherapy. In clinical chemotherapy, some patients often develop chemoresistance quite rapidly, the underlying mechanism remains elusive. Herein, we report that a transient exposure to chemotherapeutic agents can acutely promote the intercellular transfer of ABCB1 through stimulating Rab8B-mediated secretion of microvesicles (MVs) containing ABCB1 in drug-resistant donor cells, and promoting parallelly the endocytic recycling of ABCB1 in recipient tumor cells via the downregulation of Rab5. Sensitive recipient cells take up these ABCB1-incorporated MVs by a clathrin- and dynamin 2- dependent endocytic pathway, thereby acquiring a transient resistance to chemotherapeutic agents which are ABCB1 substrates. More fascinatingly, ABCB1 molecules can locally or distantly transfer to recipient tumor cells and respond to chemotherapeutical drug in the xenograft tumor models. In some cases of patients with NSCLC, a variable increase of ABCB1 surface expression was also detected in the peripheral blood monocyte subpopulations after they received the first chemotherapy. Our findings proposed a novel molecular mechanism of how sensitive cancer cells rapidly acquire the emergency resistance to chemotherapeutic agents by stimulating intercellular transfer of ABCB1. The precise modulation of this process may provide a valid therapeutic strategy to alleviate the MDR phenotype for successful treatment.

Citation Format: Xiaokun Wang, Dongjuan Qiao, Likun Chen, Liyan Huang, Meng Xu, Zhen Chen, Fang Wang, Zhesheng Chen, Musheng Zeng, Li-Wu Fu. Chemotherapeutical agent triggers transient resistance of cancer cells by promoting ABCB1 intercellular transfer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3180. doi:10.1158/1538-7445.AM2017-3180
Abstract 3185: Adipocyte-derived hydrogen peroxide promotes chemoresistance to daunorubicin in leukemia cells
Authors: Parmentier Jean-Hugues , Dieli-Conwright Christina M. , Mittelman Steven D.
Published: July 2017

Background: Adipocytes protect acute lymphoblastic leukemia (ALL) cells from several chemotherapeutic drugs. This protection is associated with an oxidative stress response in adipocytes. Since adipocytes are known to release reactive oxygen species, and anthracyclines are sensitive to inactivation mediated by hydrogen peroxide (H2O2), we investigated whether adipocyte release of H2O2 into the micro-environment might contribute to drug resistance of ALL cells.

Methods: Pre-B lymphoblast/myeloblast BV173 cells in complete media (CM) were co-cultured for 3 days in transwells over 3T3-L1 fibroblasts or adipocytes. Viable cells were determined by Trypan blue exclusion for BV173 cells. Leukemia Conditioned Media (LCM) was prepared from BV173 cultured for 48 hrs. Total antioxidant capacity was measured by ABTS-based assay. H2O2 released in the extracellular compartment of adipocytes was monitored with Amplex Red and ROS-Glo.

Results: BV173 cells were protected from DNR in presence of 1 mM H2O2 (9.34±2.15x104 vs. 3.33±1.01x104 viable cells with and without H2O2, p=0.03). Interestingly, this protection was only observed when pyruvate was present in the culture media at equimolar concentrations with H2O2 (DNR: 4.14±2.14x104; DNR+pyruvate: 4.17±1.53x104; DNR+H2O2: 3.77±2.74x103; DNR+pyruvate+H2O2: 3.21±0.59x105, p=0.02). Adipocytes released H2O2 into the media measured with Amplex Red fluorescence in a time-dependent manner significantly more than fibroblasts (1.96-fold, p=0.001). LCM potentiated adipocyte H2O2 released (1.5-fold over CM, p=0.05). Human adipose tissue biopsies from breast cancer survivors also released H2O2 (4.37x103 RFU for biopsies vs. 0.65x103 RFU for HBSS, 90 min, n=5). Co-culture of adipocytes and BV173 cells increases the survival of BV173 to DNR treatment (1.55±0.34x105 vs. 6.88±2.91x103 viable cells with and without adipocytes, p=0.006). Adipocyte-mediated protection of BV173 cells was reversed in a dose-dependent manner by adding the H2O2-inactivating enzyme catalase to the extracellular media (7.28±1.44x104 vs. 15.58±3.48x104 viable cells with and without 500 U/ml catalase, p=0.01).

Conclusion: These data show that adipocytes release H2O2, which in the presence of pyruvate, protects ALL cells from DNR. Further work is needed to determine whether adipocytes secrete significant amounts of H2O2 in the bone marrow micro-environment to contribute to anthracycline resistance.

Citation Format: Jean-Hugues Parmentier, Christina M. Dieli-Conwright, Steven D. Mittelman. Adipocyte-derived hydrogen peroxide promotes chemoresistance to daunorubicin in leukemia cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3185. doi:10.1158/1538-7445.AM2017-3185
Abstract 3202: Pharmacologic modulation of Sigma1 induces autophagic degradation of programmed death-ligand 1 in cancer cells
Authors: Maher Christina M. , Thomas Jeffrey D. , Longen Charles G. , Haas Derick A. , Oyer Halley M. , Tong Jane Y. , Kim Felix J.
Published: July 2017

Emerging evidence suggests that Sigma1 (also known as sigma1 receptor) is a unique ligand-operated integral membrane chaperone or scaffolding protein that contributes to cellular protein homeostasis. Previously, we found that treatment of various cancer cell lines with some prototypic small molecule modulators of Sigma1 can engage endoplasmic reticulum (ER) associated protein homeostasis pathways including the unfolded protein response and autophagy. Programmed death-ligand 1 (PD-L1) is a type 1 integral membrane glycoprotein that is processed and transported through the ER and secretory pathway of tumor cells. PD-L1 expressed at the surface of tumor cells can act as a T-cell inhibitory checkpoint molecule that inactivates tumor infiltrating immune cells that express PD-1, its cognate receptor. Here, we show that Sigma1 physically associates with PD-L1. In triple negative breast and androgen-independent prostate cancer cells, PD-L1 protein levels are suppressed by both RNAi mediated knockdown of Sigma1 and pharmacological modulation of Sigma1. We observe decreased cell surface and intracellular levels of PD-L1 by flow cytometry and biochemical subcellular fractionation respectively, which corresponds with a dose-responsive decrease in functional PD-L1/PD-1 interaction in a co-culture of cancer cells and T-cells. Inhibitors of autophagy block this suppression of PD-L1 protein levels, suggesting PD-L1 is degraded away by autophagy after Sigma1 modulation. Through confocal microscopy, we show that Sigma1 modulation results in colocalization of PD-L1 and GFP-LC3, a marker of autophagosomes. From these conclusions, we hypothesize that autophagic degradation of nascent PD-L1 after Sigma1 modulation plays a key role in preventing the transport of functional PD-L1 to the plasma membrane. Together, these data demonstrate that Sigma1 modulators have the potential to act as novel therapeutic agents in PD-1/PD-L1 blockade strategies.

Citation Format: Christina M. Maher, Jeffrey D. Thomas, Charles G. Longen, Derick A. Haas, Halley M. Oyer, Jane Y. Tong, Felix J. Kim. Pharmacologic modulation of Sigma1 induces autophagic degradation of programmed death-ligand 1 in cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3202. doi:10.1158/1538-7445.AM2017-3202
Abstract 3205: A nanomolar potency small-molecule compound against castration-resistant and bone metastatic prostate cancer
Authors: Mamouni Kenza , Gera Lajos , Li Xin , Wu Daqing
Published: July 2017

A standard treatment for prostate cancer (PCa) is androgen deprivation therapy (ADT) that suppresses androgen receptor (AR) signaling axis. Although initially responsive, most patients receiving ADT eventually develop metastatic castration-resistant prostate cancer (CRPC), with more than 90% of them exhibiting bone metastases. A mechanism by which CRPC cells evade ADT is the expression of constitutively active AR variants (AR-Vs), such as the well-characterized AR-V7. Recently we developed GH501, a flurbiprofen-modified small-molecule compound, and investigated its anti-cancer activity and mechanism of action in pre-clinical models of CRPC. At nanomolar range, GH501 effectively induces cell cycle arrest and apoptosis in CRPC cells regardless of their resistance status to enzalutamide treatment. RNA-seq analysis of GH501 combined with Western blotting analysis identified key targets implicated in CRPC progression, including the full-length AR, AR-V7 variant, and other important genes implicated in CRPC progression. Importantly, low doses of GH501 effectively inhibit the skeletal growth of CRPC in a xenograft model without obvious in vivo toxicities. These preclinical results indicate that GH501 is a promising small-molecule compound that can be further developed for the treatment of lethal prostate cancer.

Citation Format: Kenza Mamouni, Lajos Gera, Xin Li, Daqing Wu. A nanomolar potency small-molecule compound against castration-resistant and bone metastatic prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3205. doi:10.1158/1538-7445.AM2017-3205
Abstract 3234: Development of potent and selective antibody-drug conjugates with pyrrole-based KSP inhibitors as novel payload class
Authors: Lerchen Hans-Georg , Wittrock Sven , Griebenow Nils , Lobell Mario , Rebstock Anne-Sophie , Cancho-Grande Yolanda , Stelte-Ludwig Beatrix , Mahlert Christoph , Greven Simone , Sommer Anette , Berndt Sandra , Terjung Carsten , Apeler Heiner , Kreft Bertolt , Jautelat Rolf
Published: July 2017

The number of cytotoxic payload classes with different modes-of-action which have been successfully employed in antibody-drug conjugates (ADC) is still rather limited. So far, only ADCs with microtubule inhibitors, DNA binding payloads or topoisomerase I inhibitors have been advanced into clinical testing. To this end, the identification of ADC payload classes with a novel mode of action will increase therapeutic options and potentially help to overcome resistance. Inhibitors of kinesin spindle protein (KSP/Eg5) have generated interest due to their high antitumor potency. However, transferring the preclinical potency of small molecule KSP inhibitors (KSPis) into highly efficient clinical regimens with a sufficient therapeutic window has remained challenging. We have investigated a new pyrrole subclass of KSPis which showed subnanomolar potency against a large panel of tumor cell lines for their utility as a novel payload class in ADCs. Towards this goal different attachment sites for linkers have been explored in the KSPi molecule which were found compatible with cleavable and/or non-cleavable linkers. Subnanomolar potency and selectivity of ADCs with antibodies targeting either HER2, EGFR or TWEAKR could be demonstrated in vitro. For selected ADCs, the intracellular trafficking and metabolite formation was investigated and KSP inhibition was confirmed as the ADC mode of action. Depending on the linker composition differential profiles of the ADC metabolites with regard to efflux, cellular permeation, and bystander effect have been achieved. Moreover, specific accumulation in the tumor versus other tissues was demonstrated in biodistribution studies in vivo. In conclusion, KSP inhibitors have been established as a versatile new payload class for the generation of highly potent and selective ADCs.

Citation Format: Hans-Georg Lerchen, Sven Wittrock, Nils Griebenow, Mario Lobell, Anne-Sophie Rebstock, Yolanda Cancho-Grande, Beatrix Stelte-Ludwig, Christoph Mahlert, Simone Greven, Anette Sommer, Sandra Berndt, Carsten Terjung, Heiner Apeler, Bertolt Kreft, Rolf Jautelat. Development of potent and selective antibody-drug conjugates with pyrrole-based KSP inhibitors as novel payload class [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3234. doi:10.1158/1538-7445.AM2017-3234
Abstract 3253: Targeting G-quadruplex nucleic acids: a series of β-carboline alkaloids with new skeletons from the seeds of Peganum harmala
Authors: wang Kaibo , Hua Huiming , Yang Danzhou
Published: July 2017

G-quadruplexes are DNA secondary structures implicated in essential physiological and pathological processes, such as tumorgenesis. Small molecules which can stabilize or induce G-quadruplex formation have potential as antitumor agents through the alteration of oncogene expression levels or the disruption of telomere maintenance. Targeting G-quadruplex nucleic acids, we screened 17 medicinal plants for binding activity to a model G-quadruplex d(TTGGGTT)4 system by 1H NMR experiment. We found that the crude extract of Peganum harmala L. seeds showed the most potential binding activity and specific cytotoxicity against the PC-3 cancer cell line with an IC50 value of 13.65 μg/mL. Subsequently, 1H NMR and bioassay co-guided isolation of the extract of P. harmala L. was performed and obtained 21 new alkaloids, including 10 novel β-carboline alkaloids with unprecedented carbon skeletons, and 12 known analogues. Their structures including the absolute configurations were determined by extensive analysis of spectroscopic data, X-ray crystallography, ECD calculations, and ECD exciton chirality approaches. The antiproliferative activities and G-quadruplex binding activities were evaluated for these newly discovered and previously reported alkaloids. Some of the isolates showed pronounced cytotoxic effects with IC50 values below 10 µM and significant G-quadruplex binding activities. More interestingly, pegaharmine D (4), which showed the strongest G-quadruplex interaction, exhibited significant cytotoxic activity against HL-60, PC-3 and SGC-7901 cell lines, with IC50 values of 3.81 ± 0.32, 11.52 ± 0.62, and 15.16 ± 0.42 µM, respectively. The G-quadruplex interactions positively correlated with antiproliferative activities suggesting these β-carboline alkaloids may exert their anti-cancer effects through G-quadruplex interactions. This work contributed a practical strategy at first time for the discovery of novel G-quadruplex ligands from natural products and provided potential insights for using β-carboline alkaloids as anticancer lead compounds specifically targeting G-quadruplexes.

Citation Format: Kaibo wang, Huiming Hua, Danzhou Yang. Targeting G-quadruplex nucleic acids: a series of β-carboline alkaloids with new skeletons from the seeds of Peganum harmala [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3253. doi:10.1158/1538-7445.AM2017-3253
Abstract 326: Baseline IL-17 receptor signaling is essential for controlling aberrant JNK-dependent cellular proliferation via maintenance of endogenous level of ubiquitin-editing enzyme A20
Authors: Yan Chi , Lei Yang , Greenshields Anna L. , Hoskin David W. , Lin Tong-Jun , Wang Jun
Published: July 2017

The molecular mechanisms underlying aberrant activation of NF-κB and JNK in cancer remain incompletely understood. Here, we demonstrate that baseline IL-17 receptor (IL-17R) signaling is essential for controlling aberrant NF-κB and JNK activation, and restraining JNK-dependent homeostatic cellular proliferation. Using a shRNA knockdown approach, we demonstrated in B16 melanoma and 4T1 breast carcinoma murine cell lines that IL-17RA silencing markedly enhanced tumor cell growth in vitro and in vivo. Through mapping IL-17R signaling pathways, we further demonstrated that baseline IL-17A/IL-17R signaling actively restrained JNK phosphorylation in vitro and in vivo via the maintenance of basal expression of the ubiquitin-editing enzyme A20, a negative regulator of NF-κB and JNK. Remarkably, IL-17RA reconstitution evidently restored the A20 level, and suppressed cell proliferation and JNK activity in tumor cells. The reconstitution of A20 in IL-17RA knockdown subclones was able to restore the normal rate of cellular proliferation and associated JNK/c-Jun activity. Finally, meta-analysis of human cancer microarray and RNA-Seq datasets confirmed significant co-expression of IL-17RA and A20. Furthermore, alterations (mutation, upregulation or downregulation) of IL-17RA level in melanoma, ER+ breast cancer and colorectal cancer patients were associated with poorer overall survival compared to the respective patients with normal baseline IL-17RA expression. Together, our data demonstrates a previously unrecognized molecular mechanism underlying aberrant activation of NF-κB and JNK in cancer cells. This work highlights the unique biological role of proinflammatory IL-17R signaling in the maintenance of A20 to regulate the pathogenesis of human cancer, which draws caution on the utility of IL-17A neutralizing antibody in cancer therapy.

CY is a PhD student supported by the graduate student scholarship from the IWK Health Centre and received a trainee award from the Beatrice Hunter Cancer Research Institute with funds provided by the Cancer Research Training Program as part of The Terry Fox Foundation Strategic Health Research Training Program in Cancer Research in CIHR.

Citation Format: Chi Yan, Yang Lei, Anna L. Greenshields, David W. Hoskin, Tong-Jun Lin, Jun Wang. Baseline IL-17 receptor signaling is essential for controlling aberrant JNK-dependent cellular proliferation via maintenance of endogenous level of ubiquitin-editing enzyme A20 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 326. doi:10.1158/1538-7445.AM2017-326
Abstract 3260: Training for cancer surgery in Sub Saharan Africa
Authors: Jalloh Mohamed , Gueye Serigne Magueye
Published: July 2017

BACKGROUND: Low- and middle-income countries (LMICs) face both training and infrastructural challenges for surgical care, particularly for cancer. Practitioners charged with caring for these patients have few options for basic or advanced training.

OBJECTIVES: To describe the training options for cancer surgery in Sub Saharan Africa

METHODS: The different methods of training are described and the advantages and limits of each methods is highlighted.

RESULTS: Training during residency and onsite fellowship are a good option but requires an appropriate number and capacity of training programme. International fellowships have the limitation of readjustment back home for the trained fellow. Onsite International training missions like IVUmed’s missions have the advantage of “Teach One, Reach Many” outcome where a whole team in trained in accordance of local needs and the participation of all stakeholders.

CONCLUSIONS: Long-term program commitments; effective communication; and a shared vision among the program site, the coordinating nongovernmental organization, and supporting organizations facilitate the development of thriving surgical teaching programs capable of serving local communities and conducting outreach training.

Citation Format: Mohamed Jalloh, Serigne Magueye Gueye. Training for cancer surgery in Sub Saharan Africa [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3260. doi:10.1158/1538-7445.AM2017-3260
Abstract 3266: Oral rinse point of care test to predict head and neck cancer
Authors: Donovan Michael J. , Curtis Kris , Ginn Greg , Franzmann Elizabeth J.
Published: July 2017

Background: Head and neck squamous cell carcinoma (HNSCC) is the 6th most common cause of cancer mortality throughout the world affecting some 50,000 people in the US and 600,000 worldwide each year. The ability to detect the disease in a potentially malignant phase and earlier stage could have significant impact on overall outcome. Previous studies have demonstrated that a combined salivary CD44, a tumor-initiating marker, and total protein assay was able to aid in the diagnosis of HNSCC. We sought to understand the performance characteristics of these biomarkers in a prospective population using a qualitative, point-of-care assay (POC) which consists of a cassette with a colorimetric read-out based on a pre-determined threshold for both CD44 and total protein. We also performed results from same samples with a quantitative lab-based test.

Methods: Saline oral rinse specimens (~5ml) from 134 patients (84 HNSCC cases; 50 controls) were obtained from biorepositories. Samples were thawed, gently swirled, placed in a standard collection cup. 600ul were removed for lab assay prior to POC test. The tapered end of the POC cassette was submerged in rinse for 20’; levels of CD44 and total protein (TP) were evaluated by two operators. POC test results were compared between operators and with lab test results using Cohen’s kappa coefficient and McNemar’s test, sensitivity(Se), specificity(Sp), NPV and PPV.

Results: 95% HNSCC patients (cases) were mean 60 years of age, 60% male, 97% white and 74% smokers vs. 43 years, 28%, 96% and 0% respectively, for controls. POC was positive with either CD44 or TP above threshold. Weighted kappa yielded 75% and 72% for CD44 and TP respectively between operators. With a prevalence of 9.27: POC: NPV 94%, PPV 10%; variable TP cut-off produced Se71-84% and Sp30%-50%. McNemar and Kappa for both lab CD44 and TP vs POC indicated moderate agreement; independently both POC and lab produced NPV >90%.

Conclusions: Concordance of the POC assay between operators and moderate agreement with a quantitative lab assay provides supportive evidence for clinical application of the POC assay as an aid in the diagnosis for HNSCC. Additional studies are underway to confirm these observations.

Citation Format: Michael J. Donovan, Kris Curtis, Greg Ginn, Elizabeth J. Franzmann. Oral rinse point of care test to predict head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3266. doi:10.1158/1538-7445.AM2017-3266
Abstract 3267: Combined effect of multiple gene polymorphisms on cancer risk stratification
Authors: Andavolu Radhika Gade , Rodriguez Olivia , Rubakovic Anastasia Al , Stafford Catherine , Andavolu Murthy V.
Published: July 2017

Cyclin D1 (CCND1) G870A polymorphism has been known to be a risk factor in multiple cancers. Cyclin D1 is a cell cycle regulator frequently mutated, amplified and overexpressed in a variety of tumors. Activation and over expression of CCND1 have been found in variety of tumors and alterations in CCND1 are thought to be involved in carcinogensis. CCND1 polymorphism A870G interferes with splicing and studies showed DNA damage in cells from subjects with ‘A’ allele to bypass G1/S check point of the cell cycle control mechanism more easily than damage in cells with G allele (wild type). A single base pair polymorphism (exon 4, G870A) in the CCND1 gene affects gene splicing. This identification and validation of contributing genetic factors such as single-nucleotide polymorphisms (SNPs) represents a critical step in the advance toward personalized medicine. Several gene expression correlation studies have been done but to our knowledge studies have not been reported on SNP’s of ERBB2 gene, ESR gene and CCND1 combined effect correlating with high risk. In this study, we examined the relationship between ERBB2 (codon 655), Estrogen receptor (ER Intron1 T<C) and cyclin D1 (Exon 4) polymorphic additive effect in cancers more specific to breast cancer. Genomic DNA was extracted from whole blood samples collected on study. The SNPs were tested by the PCR-restriction fragment length polymorphism (PCR-RFLP) method. Our results show individuals carrying CCND1 ‘A allele in combination with variant ERBB2/BsmAI uncut allele are significantly high (P<0.004) in cancer patients (N=232) as compared to controls. (N=222). Similarly individuals carrying CCND1 Variant ‘A ‘ allele in combination with ESR ‘C’ Allele showed high frequency with p<0.009. Both these combinations showed a strong and significant association with cancer but individually, ERBB2 variant did not show any significant association, ESR gene showed a borderline association and CCND1 showed strong association independent of these two gene polymorphisms. Earlier few studies have shown no association of ERBB2 mutation in agreement with the previous reports. In conclusion our data suggests that in complex diseases a single gene may not contribute to show its effect but in combination may show a profound effect in evaluating the risk.

Citation Format: Radhika Gade Andavolu, Olivia Rodriguez, Anastasia Al Rubakovic, Catherine Stafford, Murthy V. Andavolu. Combined effect of multiple gene polymorphisms on cancer risk stratification [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3267. doi:10.1158/1538-7445.AM2017-3267
Abstract 3300: Inhibition of autophagy by 3-MA enhances the effect of ursolic acid-induced apoptosis in hepatoma SK-Hep-1 cells
Authors: Wan-Ling Chuang , Ping-Yi Lin , Yao-Li Chen
Published: July 2017

Purpose

The aim of this study is to investigate the autophagic effect of Ursolic Acid (UA) on hepatoma SK-Hep-1 cells.

Methods

The cytotoxicity of UA in hepatoma SK-Hep-1 cells was measured by MTT assay, the accumulation of acidic vesicular organelles was measured by FACS, the protein expression of LC3-II was detected by immunofluorescence staining, and the autophagic protein expression was evaluated by western blotting.

Hepatoma SK-Hep-1 cells treated with a combination of autophagy inhibitor 3-Methyladenine (3-MA) and UA, then use Annexin V/PI Double Staining and western blotting to detect apoptosis and apoptotic protein levels.

Statistical Analyses

Data was expressed as the mean ± standard deviation and were compared using the Student’s t-test. A p value of <0.05 was considered to indicate statistical significance. All statistical analyses were performed using GraphPad Prism software, version 4.0 (GraphPad Software, Inc., La Jolla, CA, USA).

Preliminary Results

SK-Hep-1 cells treated with different concentrations of UA (0, 20, 40, and 60 μM). Regarding the results, the half-maximal inhibitory concentration (IC50) was 45.9 and 36.6 μM for 24 and 48 h, respectively. The FACS results showed that when increase the dose of UA could increase the percentages of autophagic populations. The anti-autophagic proteins such as Beclin, Atg-5, Atg-7, and LC3-II, in our results showed that UA decreased the protein expression of mTOR, PI3K, and p62 and PI3K/Akt/mTOR expression. Immunocytochemistry staining showed that SK-Hep-1 cells treated with UA increased the protein expression of LC3-II. The combination treatment of 3-MA and UA significantly increased the apoptotic cell death as monitored by increased protein expression of Caspase-3 and PAPR.

Conclusions

UA could induced autophagy in hepatoma SK-Hep-1 cells through inhibition of mTOR and PI3K signaling pathways. SK-Hep-1 cells treated with UA exhibited LC3-І/LC3-II conversion, increased protein expression levels of Beclin, Atg-7, and Atg-5 along with reduced protein expression levels of p62. UA-induced apoptosis was enhanced by the treatment of autophagy inhibitor 3-MA. Our findings may assist in the development of novel chemotherapeutic agents for the treatment of malignant types of liver cancer.

Citation Format: Chuang Wan-Ling, Lin Ping-Yi, Chen Yao-Li. Inhibition of autophagy by 3-MA enhances the effect of ursolic acid-induced apoptosis in hepatoma SK-Hep-1 cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3300. doi:10.1158/1538-7445.AM2017-3300
Abstract 3302: Autophagy is required for cell survival under L-asparaginase-induced metabolic stress in acute lymphoblastic leukemia cells
Authors: Inoue Jun , Takahashi Hiroyoshi , Sakaguchi Kimiyoshi , Takagi Masatoshi , Mizutani Shuki , Inazawa Johji
Published: July 2017

L-asparaginase has been used for more than three decades in acute lymphoblastic leukemia (ALL) patients and remains an essential drug in the treatment of ALL. Poor response to L-asparaginase is associated with increased risk of therapeutic failure in ALL. However, both the metabolic perturbation and molecular context of L-asparaginase-treated ALL cells has not been fully elucidated. Here we identify that treatment with L-asparaginase results in metabolic shutdown via the reduction of both glycolysis and oxidative phosphorylation, accompanied by mitochondrial damage and activation of autophagy. The autophagy is involved in reducing reactive oxygen species (ROS) level by eliminating injured mitochondria. Inhibition of autophagy enhances L-asparaginase-induced cytotoxicity and overcomes the acquired resistance to L-asparaginase in ALL cells. The ROS-p53 positive feedback loop is an essential mechanism of this synergistic cytotoxicity. Thus, our findings provide the rationale for the future development of combined treatment of L-asparaginase and anti-autophagy drug in ALL patients.

Citation Format: Jun Inoue, Hiroyoshi Takahashi, Kimiyoshi Sakaguchi, Masatoshi Takagi, Shuki Mizutani, Johji Inazawa. Autophagy is required for cell survival under L-asparaginase-induced metabolic stress in acute lymphoblastic leukemia cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3302. doi:10.1158/1538-7445.AM2017-3302
Abstract 331: SIRPB1 promotes prostate cancer cell proliferation & migration
Authors: Song Qiong , Qin Siyuan , Zou Chunlin , Wang Wenchu , Wang Lihui , Tong Haibo , Catalona William J. , Zhang Jian , Lu Yi , Wang Zhou
Published: July 2017

Signal-regulatory-protein beta 1(SIRPB1) is a member of the signal-regulatory-protein (SIRP) family that belongs to the immunoglobulin superfamily and is capable of modulating receptor tyrosine kinase-coupled signaling. The copy-number variations (CNV) at the SIRPB1 locus were associated with aggressiveness of prostate cancer in patients. To test if SIRPB1 could affect prostate cancer development and progression, we investigated the potential role and mechanisms of SIRPB1 action in prostate cancer cell lines in vitro and in xenograft tumors. Knockdown of SIRPRB1 by RNA interference resulted in significant suppression of cell colony formation, cell mobility, cell migration, and invasion. The knockdown also induced cell cycle arrest during the G0/G1 phase and a remarkable enhancement of apoptosis in PC3 prostate cancer cells. In contrast, overexpression of SIPRB1 significantly induced cell migration, invasion, colony formation and cell cycle in C4-2 prostate cancer cells. Furthermore, overexpression of SIRPB1 in C4-2 cell model enhanced its tumor take rate in nude mice. Also, SIRPB1 mRNA expression was increased in up to 39% of the prostate cancer specimens based on in silico analysis of several public databases. These results suggest that SIRPB1 is a potential oncogene in the prostate and could be used as a biomarker to identify patients at risk of developing aggressive prostate cancer.

Citation Format: Qiong Song, Siyuan Qin, Chunlin Zou, Wenchu Wang, Lihui Wang, Haibo Tong, William J. Catalona, Jian Zhang, Yi Lu, Zhou Wang. SIRPB1 promotes prostate cancer cell proliferation & migration [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 331. doi:10.1158/1538-7445.AM2017-331
Abstract 3314: Synergistic effects of chemotherapy-induced autophagy and epigenetic remodeling
Authors: Tyutyunyk Liliya , Landry Joseph , Saleh Tareq , Gewirtz David
Published: July 2017

Cytotoxic chemotherapy has been shown to enhance tumor cell immunogenicity by promoting the secretion of damage-associated molecular pattern (DAMP) molecules which, in turn, stimulates the immune response. These effects can be further stimulated by combining chemotherapy with an immunotherapy designed to enhance effector cell (CD8 T cell or NK cell) anti-tumor activity. Our studies demonstrate that knockdown of the epigenetic regulator NURF increases DNA damage (gamma H2AX staining) and autophagy (acridine orange staining) in breast tumor cells exposed to doxorubicin and enhances growth inhibition as well as suppressing the capacity of the cells to recover and proliferate. Similar increases in autophagy were observed using a small molecule inhibitor of NURF, suggesting that NURF can be targeted therapeutically. Sensitization was not observed with ionizing radiation or cisplatin. Studies are in progress to assess the nature of autophagy in the NURF KD and NURF WT cells, distinguishing between the cytoprotective, cytotoxic, cytostatic and nonprotective forms. How NURF regulates doxorubicin induced DNA damage is being investigated by mapping sites of damage genome wide. It is anticipated that enhanced cell autonomous tumor cell sensitivity in concert with improvements in tumor cell antigenicity (cell non-autonomous sensitization) achieved by NURF depletion could improve anti-tumor immunogenicity, achieve tumor regression, reduce metastasis, and possibly achieve long term remission in breast cancer.

Citation Format: Liliya Tyutyunyk, Joseph Landry, Tareq Saleh, David Gewirtz. Synergistic effects of chemotherapy-induced autophagy and epigenetic remodeling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3314. doi:10.1158/1538-7445.AM2017-3314