bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract B46: Targeting tumor-propagating cells in medulloblastoma through inhibition of G2/M cell cycle regulators
Authors: Markant Shirley , Esparza Lourdes Adriana , Barton Kelly , Sun Jesse , Wechsler-Reya Robert 
Published: March 2013

Abstract
Medulloblastoma is the most common malignant brain tumor in children. While the current treatment strategy of surgery plus radiation has a 60–80% cure rate, the survivors suffer severe side effects, including growth delays and cognitive deficits. Therefore, more effective, less toxic treatments are needed. One approach to achieving this is targeting the cells within a tumor that are capable of re-populating the tumor, known as tumor-propagating cells (TPCs). These cells are thought to be responsible for tumor resistance to conventional therapies. In the patched mutant mouse model of medulloblastoma, TPCs are marked by expression of the cell surface carbohydrate antigen CD15. Our previous studies have suggested that CD15+ cells display increased expression of genes associated with the G2/M phases of the cell cycle. Cell cycle analysis suggests that CD15+ cells move quickly through the G1 and S phases of the cell cycle, but accumulate in the G2/M phases. This accumulation in G2/M may represent a vulnerability of CD15+ TPCs, and inhibition of G2/M regulators, such as Aurora kinases, may represent one approach for targeting TPCs and overcoming therapeutic resistance. Treatment of tumor cells from patched mutant mice or human Hedgehog-associated medulloblastoma with Aurora kinase inhibitors in vitro leads to inhibition of proliferation, arrest in G2/M and apoptosis. Furthermore, in vivo treatment of tumor-bearing mice with Aurora kinase inhibitors significantly delays tumor progression and prolongs survival. Our findings suggest that targeting Aurora kinases in TPCs may represent a new approach for the treatment of human medulloblastoma.
Abstract B47: Identification of a novel ALK inhibitor active against Crizotinib-allele resistant mutants
Authors: Nicolas Jean-Paul , Calvet Loreley , Vergne Fabrice , Leroy Vincent , Garcia-Echeverria Carlos , Valtingojer Iris , Dassencourt Laurent , Herve Francoise , Serres Emerson , Delarbre Laure , Wolfrom Meredith , Lennon Amanda , Hoffmann Dietmar , Deprets Stephanie 
Published: March 2013

Abstract
Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase belonging to the insulin receptor superfamily. Activating mutations in ALK are oncogenic and cause 10% to 15% of neuroblastoma cases. Similarly, activating ALK fusions have been detected in several cancers, including ALCL (NPM-ALK in 70% of patients) and NSCLC (EML4-ALK in 3% to 7% of patients).
Several ALK inhibitors are currently undergoing clinical development, among which crizotinib has recently received marketing approval from the U.S. FDA under the name Xalkori. This nonselective ALK inhibitor has provided clinical benefit to lung cancer patients, but its sustained efficacy seems to be impaired by acquired drug resistance and several publications have already described ALK secondary mutations identified in patients who progressed while on crizotinib therapy.
In this study, we have:
Identified EML4-ALK mutations able to confer resistance to crizotinib.
A screen using the Ba/F3 system found 24 residues in the ALK kinase domain where mutations can cause crizotinib resistance. Some of these mutations (L1152R, C1156Y, F1174L, G1202R, S1206F) have been identified in lung cancer patients progressing under crizotinib treatment
Evaluated the activity of novel in-house and reference ALK kinase inhibitors against Ba/F3 cell lines stably expressing wild-type EML4-ALK and selected crizotinib-allele resistant mutantsPerformed in vivo head to head studies with a representative in-house ALK inhibitor and crizotinib to compare their pharmacodynamic properties
This work resulted in the identification of an ALK kinase inhibitor with similar potency against wild-type EML4-ALK and crizotinib-allele resistant mutants and displaying significant target coverage in in vivo settings.
Abstract B48: Sensitization of Hepatocellular Carcinoma Cells to TRAIL by a Novel Aκt/NF-kappaB Signaling Inhibitor
Authors: Omar Hany A. , Arafa El-Shaimaa A. , Weng Jing-Ru 
Published: March 2013

Abstract
Tumor necrosis factor-related apoptosis ligand (TRAIL) represents a promising cancer therapeutic agent considering its selectivity in targeting malignant cells while sparing normal cells. However, hepatocellular carcinoma (HCC) cells are intrinsically resistant to TRAIL, in part, due to the compensatory activation of nuclear factor-kappaB (NF-κB). Previously, based on the scaffold of indole-3-carbinol, we developed a potent Akt/NF-κB signaling inhibitor, OSU-A9, that exhibits in vitro and in vivo efficacy in suppressing HCC cell growth.
In this study, we report the sensitizing effect of OSU-A9 on TRAIL-induced cell death in Hep3B and Huh7 HCC cells by antagonizing TRAIL-induced NF-κB activation. Even at 1 μM, OSU-A9 could restore the sensitivity of these cells to TRAIL-mediated antitumor effect to a level comparable to that of TRAIL-sensitive PC-3 cells. Exposure to OSU-A9 led to a dose-dependent reduction in the expression and nuclear localization of RelA/p65 by suppressing Akt activation and RelA expression, which was accompanied by parallel decreases in the expression of antiapoptotic Bcl-xL, Mcl-1, cIAP1, cIAP2, and survivin. In addition, OSU-A9 upregulated death receptor (DR)5 expression via a reactive oxygen species-dependent mechanism. Concertedly, these effects gave rise to increased capsase-3 and caspase-8 activities and PARP cleavage in TRAIL-treated cells, indicative of therapeutic synergy between OSU-A9 and TRAIL. Moreover, this synergistic effect was abolished by the ectopic expression of NF-κB/p65, supporting the role of NF-κB inhibition in OSU-A9-mediated sensitization of HCC cells to TRAIL. Taken together, the ability of OSU-A9 to accentuate TRAIL-induced apoptosis by inactivating NF-κB signaling might foster a promising therapeutic strategy for HCC.
Abstract B54: Role of inverted Alu repeats in triggering TMPRSS2-ERG fusions in prostate cancer following irradiation
Authors: Singh Sheetal , Cheung Jean P. , Ho Bay , Vaughan Andrew , Ghosh Paramita 
Published: March 2013

Abstract
Radical Prostatectomy and radiation therapy are the two most common treatments for primary prostate cancer (PCa). However, patients treated with radiotherapy are at greater risk for metastases compared to those treated with radical prostatectomy. Among other factors regulating biochemical or clinical recurrence is the formation of gene fusions. Ionizing radiation (IR) can trigger formation of TMPRSS2-ERG in PCa which may facilitate the development of more aggressive clones, especially in men with an intact androgen axis. Bioinformatics analysis has indicated that breakpoint regions of TMPRSS2 and ERG are rich in Alu elements, including inverted Alu repeat that are inherently unstable when in close proximity. Previous work in multiple cell lines showed that adjacent inverted Alu repeats, but not tandem or single Alu's, are recombinationally unstable subsequent to IR exposure. Based on these results, we hypothesize that regions containing inverted Alu repeats in the prostate genome are vulnerable to DNA strand breaks and rearrangements in hormone naïve PCa patients undergoing IR therapy.
As gene fusions require each gene to be broken prior to fusion, the effect of irradiation on ERG fragmentation was studied using ligation mediated-PCR. Data from two androgen-sensitive PCa cell lines, PC-346C and LNCaP, showed that after irradiation DNA breaks were introduced preferentially in proximity to an Alu inverted repeat, Alu-Y pair, in intron 3 of ERG. To determine if the enhanced fragmentation observed in this region is translated into rearrangements, FISH (fluorescence in-situ hybridization) probes were designed to bracket the area of interest in ERG. In addition, the same region has been analyzed by inverse-PCR to detect ERG rearrangements. Application of these techniques will enable a better understanding of those mechanisms driving the formation of fusion genes in the proximity of Alu repeats.
Abstract B58: The ATP-competitive mammalian target of rapamycin (mTOR) inhibitors suppress proliferation and induce apoptosis in the acquired rapamycin resistant breast cancer cells
Authors: Tzung-Ju Wu , Chi-Kwan Tsang , Yan-Jie Zhang , Steven Zheng X.F. 
Published: March 2013

Abstract
The mammalian target of rapamycin (mTOR) is the major regulator of cell growth, metabolism and survival. The anti-cancer effect of allosteric mTOR-inhibitors, rapamycin and its analogs (rapalogs), has been tested extensively in different types of cancer cells. However, there is only limited clinical efficacy observed by treatment of these traditional mTOR inhibitors, partly due to the occurring of acquired rapamycin resistance (ARR). Several new mTOR inhibitors have been developed which specifically target to the catalytic sites of mTOR by competing with ATP binding, and are suggested to be more effective in inhibiting mTOR signaling and cell growth. However, their effect and mechanisms in ARR cells are not clear yet. In the present study, we used an in vitro model of acquired rapamycin-resistant (ARR) breast cancer cells to evaluate the efficacy of two major classes of ATP-competitive mTOR inhibitors, PI3K/mTOR dual and mTORC1/mTORC2 inhibitors. We found that ATP-competitive mTOR inhibitors acutely suppress the proliferation and prominently inhibit PI3K/mTOR signaling of ARR breast cancer cells. In contrast to the cytostatic effect of rapamycin, the ATP-competitive mTOR inhibitors induced apoptosis in ARR breast cancer cells. Unexpectedly, one of PI3K/mTOR dual inhibitors we tested, PI-103, only transiently inhibits its proposed signaling targets and the anti-proliferation effects are possibly mediated through the off-target mechanism. Our results support the rationale to use ATP-competitive mTOR inhibitors to treat rapamycin-resistant breast cancer cells and highlight the putative off-target effect of the new generation of mTOR inhibitor on cancer cells.
Abstract B59: MET gene copy number related to radiation treatment response and prognosis in breast cancer
Authors: Veenstra Cynthia , Pérez-Tenorio Gizeh , Fornander Tommy , Nordenskjöld Bo , Stål Olle 
Published: March 2013

Abstract
The hepatocyte growth factor receptor (HGFR), also known as the Met receptor, promotes cell survival and proliferation by activating signaling pathways such as the PI3K/Akt and RAS/MAPK pathway. HGFR, coded by MET, has been shown to be abundant in several cancers and in some cases it interferes with treatment response. In vitro, HGFR has been shown to be upregulated and activated after radiotherapy, increasing the protection from apoptosis and thus increasing radiation resistance. In this study, it was aimed to determine the number of MET gene copies in breast tumors and correlate these findings with different clinicopathological parameters that were available in this material. Tumors of 172 patients with primary breast cancer were analyzed for MET using qPCR. Increased MET copy number (three or more copies) was found in 34% of the tumors. Five or more gene copies were found in 4.7% of the patients and indicated a significantly higher risk of developing distant metastasis. For the patients that received radiotherapy as the only postoperative treatment, the number of MET copies was associated with increased risk of distant metastasis. In terms of locoregional recurrence, it was found that increased MET copy number was associated with worse response to postoperative radiation therapy compared with chemotherapy. These results suggest that radiotherapy in combination with a Met inhibitor might be an option for patients with increased MET gene copy number to overcome radiation resistance.
Abstract B6: PEGPH20 depletion of pericellular hyaluronan sensitizes high hyaluronan-producing tumor cells in antibody-dependent cell-mediated cytotoxicity
Authors: Singha Netai C. , Jiang Ping , Zimmerman Susan , Connor Robert , Frost Gregory I. , Huang Zhongdong , Shepard H. Michael 
Published: March 2013

Abstract
Monoclonal antibodies (MAbs) have been developed successfully as part of the anticancer armamentarium. However, even in cases where the target of the antibody is stably and abundantly expressed, efficacy often falls below expectations. The tumor microenvironment (TME) has previously been shown to contribute to resistance to MAb therapy because matrix-associated high interstitial fluid pressure inhibits efficient drug penetration (1). Hyaluronan is an important component of the extracellular matrix (ECM) in about 25% of tumors, and 56% of breast cancers. This glycosaminoglycan is produced by malignant and stromal cells and acts to cross-link ECM proteins, contributing to the desmoplastic phenotype. Accumulation of HA has been associated with more aggressive malignancy (2).In this work, we show that &gt;50% of p185HER2-overexpressing breast tumors have a high accumulation of HA (HA+3). We hypothesized that tumor cells which overexpress HA create a protective “turtle shell” when it cross-links other ECM proteins (e.g., versican), and this pericellular structure protects the HER2-overexpressing tumor cell from attack by antibody-mediated cellular cytotoxicity (ADCC). SKBR3 (overexpressing p185HER2) and MDA-MB-231 (expressing EGFR) breast tumor cells were transfected with hyaluronan synthase 2 (HAS2), creating SKBR3/HAS2 (HA+3) and MDA-MB-231/HAS2 (HA+2), enabling these cells to form substantial pericellular matrices. NK-cell/trastuzumab/cetuximab-mediated ADCC is diminished in both of the HAS2-transfected cell types, suggesting that HA accumulation may contribute to tumor cell resistance to ADCC. Similarly, when these cells are treated in vitro with PEGPH20, a pegylated PH20 hyaluronidase (3), sensitivity to trastuzumab/cetuximab-mediated ADCC of the HAS2-overexpressing tumor cells is increased by up to 2-fold. These experiments show that the pericellular matrix coat (“turtle shell”) of high HA-producing tumor cells can inhibit the access of human immune cells to target cells, and that this effect can be reversed by depleting HA using PEGPH20. In vivo studies have shown that only PEGPH20, and not native PH20, has the bioavailability to induce antitumor activity in vivo. Models are currently in development to test whether PEGPH20 will enhance the activity of therapeutic MAbs in vivo.
Abstract B60: Overcoming drug resistant cancer by hyaluronic acid based nanogel formulated with anticancer drugs
Authors: Wei Xin , Senanayake Thulani H. , Vinogradov Serguei V. 
Published: March 2013

Abstract
One of major challenges of current anticancer therapies is the overcoming of emerging drug resistances and the preventing of tumor relapse. Among different causes of tumor resistance to therapy, the most important is probably the presence of a population of cancer initiating/stem cells (CSC) distinguished from other cancer cells by low metabolic activity, protective apoptotic signaling pathways and overexpression of drug efflux transporters [1, 2]. Many drug-resistant tumors and CSC display the overexpressed levels of CD44 receptor, a cellular glycoprotein binding hyaluronic acid (HA) [3]. The HA-CD44 interaction plays a prominent part in mediating cellular and intercellular events during cancer development. For biomedical applications, HA has been actively studied as a scaffold for tissue engineering and targeting moiety for drug delivery [4]. Here, we report an advanced design of HA-based polymeric nanogel-drug formulations with stronger activity compared to free drugs, which can potentially target CD44-expressing drug-resistant tumor cells.
The novel nanogels are based on the biocompatible and biodegradable HA-drug conjugates with a high drug load and linked hydrophobic moieties (e.g., cholesterol), which are capable of folding into nanogels in aqueous media. A set of nanogel conjugates of poorly soluble anticancer drug, including curcumin, etoposide and salinomycin, was obtained, characterized and studied in cancer cell cultures. Cholesterol is a common cellular component that was expected to facilitate nanogel-membrane interaction and the intracellular transport of these drugs. The drug content in nanogel conjugates was as high as 15–20% (NMR analysis). These nanogels formed very small and uniform particles of 30–40 nm in diameter as determined by dynamic light scattering. The small size of nanogels can facilitate passive tumor accumulation through leaky neovasculature (EPR effect) and drug distribution in tumor tissue. Cytotoxicity assays (MTT) demonstrated stronger anticancer activity of nanogel-drug conjugates compared to free drugs and HA-drug conjugates in human breast carcinoma cells in vitro. Fluorescent microscopy confirmed that these nanogels are internalized by receptor-mediated endocytosis depending on the expression of CD44 receptors on the surface of cancer cells. Potential further developments would include an optimization of the hydrophilic-lipophilic balance of these nanogel-drug conjugates, introduction of diagnostic and vector molecules, and the development of dual-drug nanoformulations. In conclusion, we developed and characterized in vitro a novel HA-based nanogel drug delivery and theranostic platform that exhibits high anticancer activity and has a potential to become a novel therapy for overcoming tumor drug resistance.
Abstract B63: Heterologous expression of serine palmitoyltransferase-1 alters chemosensitivity and multidrug resistance profile of human cancer cells of different tissue origins
Authors: Yerokun Tokunbo 
Published: March 2013

Abstract
The progression of human brain, bladder and prostate cancers, considered inflammatory cancers, is characterized by the acquisition of metastatic and drug resistance profiles which remain major impediments to the efficacious delivery of therapeutic intervention. Recent localization and protein interaction studies of the sphingolipid metabolism protein, serine palmitoyltransferase-1, SPTLC1, suggest a signaling, other than metabolic role during cellular response to diverse stress stimuli. The current study examined chemosensitivity to genotoxic compounds by a set of SPTLC1 recombinant cancer cell lines. When exposed to the anti-cancer drugs celecoxib and fenretinide, SPTLC1 localization as determined by confocal immunofluorescence microscopy showed its translocation to focal adhesion sites. This allows for possible interaction and crosstalk with other stress response proteins involved in regulating cell growth, differentiation, proliferation, apoptosis, migration and other processes by which cells respond to stress stimuli. Stress-inducible gene expression profile of cytochrome p450 transcripts shows differential attenuation of the Cyp1A1, 1A2 and 3A4 species. Altered expression of the genes for the cytochrome p450 xenobiotic metabolism proteins can have profound effect on the toxicity of anticancer drugs especially those with narrow therapeutic window. Taken together, the heterologous expression of a C-terminal modified SPTLC1 gene in the human cancer cell lines used in this study was found to mediate an altered drug response profile consistent with acquisition of a multidrug resistance phenotype. This is exemplified in increased resistance to anti-proliferative effect of therapeutic drugs, differential attenuation of transcriptional expression of Cyp450 species, as well as, chemical induced DNA fragmentation. The observations further support a general role for SPTLC1 in cellular stress response and its potential contribution in cellular resistance to cytotoxic drugs.
Abstract B7: Annexin V inhibits local but not systemic murine fibrosarcoma growth by blocking phosphatidylserine
Authors: Masadeh Maen , Yin Chaobo , Shilyansky Joel 
Published: March 2013

Abstract
Introduction: Phosphatidylserine (PS), a phospholipid expressed on the cytoplasmic surface of plasma membrane, becomes externalized during apoptosis and regulates immune activation. During our previous studies, we found that live tumor cells can express PS on the cell surface. We hypothesized that PS expression allows tumors to escape immune destruction, and blocking PS with annexin V (AnV) would retard tumor growth.
Materials and methods: CMS5 fibrosarcoma tumor cells were engineered to secrete AnV. Balb/c mice were inoculated subcutaneously with 105-106 CMS5 cells. Tumor growth was determined. Data was analyzed using student t-test.
Results: WT tumors grew significantly faster than AnV secreting tumors, with average size of 0.876 cm3 compared to 0.320 cm3 (p&lt;0.05) in immune competent but not in SCID mice. To test whether AnV secreting tumors are intrinsically altered we inoculated mice with a mixture of 25% AnV secreting and 75% WT tumor cells. Growth of mixed cell tumors was identical to AnV secreting tumors, and was significantly smaller than WT tumors, 0.876 cm3 compared to 0.324 cm3 (p&lt;0.05). To determine whether the effect of AnV was local or systemic mice were inoculated with tumor cells on each flank. Regardless of the type of tumor on the opposite side, WT tumors grew significantly faster than AnV secreting tumors with average size of .684 cm3 versus 0.345 cm3 (p&lt;0.05).
Conclusion: We demonstrated blocking tumor PS with AnV retards local tumor growth. The effects of AnV require an intact immune system. These findings suggest that PS promotes tumor tolerance and blocking PS with AnV may be used in future immunotherapy studies.
Abstract IA1: Keynote Presentation: BRAF and RAS signaling in melanoma from basic to translational and clinical research
Authors: Marais Richard M. 
Published: March 2013

Abstract
BRAF is a protein kinase that is mutated in about half of human melanomas. Its activator, the small G-protein NRAS, is mutated in another 20% of cases. Drugs that inhibit BRAF mediate impressive responses in melanoma patients whose tumors carry mutations in BRAF, but are not effective in patients whose tumors express wild-type BRAF. Unexpectedly however, whereas BRAF drugs inhibit MEK/ERK signaling in melanoma cells that express oncogenic BRAF, they activate MEK/ERK signaling in cells that express oncogenic RAS. This paradoxical activation of MEK/ERK signaling in melanoma cells that express oncogenic RAS occurs because BRAF drugs drive the formation of dimers between BRAF and a closely related family member, called CRAF. These hetero- and homo-dimers contain one partner that is drug-bound and one partner that is drug-free, and the drug-bound partner activates the drug-free partner through a conformational change, or by acting as a scaffold protein. Notably, this paradoxical activation drives the formation of non-melanoma skin lesions (keratoacanthomas, squamous cell carcinomas) in about a third of patients. Using a two-stage skin carcinogenesis model, we find that this is not because BRAF inhibitors are tumor promoters per se; rather they act by accelerating the inevitable in susceptible patients by driving the growth of pre-existing lesions through paradoxical RAF activation. We also find that nilotinib is a weak RAF inhibitor that activates the RAF paradox and thereby drives survival in drug-resistant chronic mylogenous leukemia (CML) cells. Our data show how improved understanding of signaling responses to BRAF inhibitors can lead to improved patient care.