bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2383: IL-6 and RANTES mediate the cross-talk between tumor cells and CAFs in the esophageal tumor microenvironment
Authors: Karakasheva Tatiana A. , Soni Monica , Waldron Todd , Rustgi Anil K.
Published: August 2015

Desmoplasia, or deposition of connective tissue proper in the stroma, is a key characteristic of esophageal squamous cell carcinoma (ESCC). The cellular component of connective tissue proper is comprised of fibroblasts, and cancer-associated fibroblasts (CAFs) are widely recognized as a major constituent of the tumor microenvironment (TME). The purpose of this study was to identify tumor-promoting factors that are secreted as a result of the crosstalk between CAFs and tumor cells in ESCC.

We have performed a comprehensive cytokine array and found that IL-6 and RANTES (also known as CCL5) are significantly overexpressed in conditioned media from co-culture of esophageal CAFs and ESCC cells, compared to mono-culture. Both proteins are known to play important roles in the development of multiple types of cancer, mostly via activation of the STAT3 signaling pathway. We have demonstrated that co-culture with fibroblasts prompts the ESCC cells to acquire a more mesenchymal phenotype and express potent mediators of cell migration and invasion, such as matricellular proteins (periostin, fibrillin, osteonectin) and hepatocellular growth factor (HGF). Furthermore, knockdown of IL-6 suppresses invasiveness and proliferation of human ESCC cells in our 3D organotypic culture model. We have also performed staining of tissue samples from ESCC patients and found that, compared to normal esophagus, expression of IL-6 and RANTES is enhanced in ESCC in both epithelial cells and fibroblasts.

In summary, our findings indicate that IL-6 and RANTES are responsible for migration and invasion of ESCC cells promoted by CAFs in the tumor microenvironment. This is the first report of such a dual induction of these specific cytokines in ESCC, and it provides a rationale for dual inhibition of IL-6 and RANTES as novel therapy for ESCC, and possibly other types of cancer.

Supported by NCI P01 CA098101.

Citation Format: Tatiana A. Karakasheva, Monica Soni, Todd Waldron, Anil K. Rustgi. IL-6 and RANTES mediate the cross-talk between tumor cells and CAFs in the esophageal tumor microenvironment. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2383. doi:10.1158/1538-7445.AM2015-2383
Abstract 2392: Hyaluronan-dependent growth of human triple negative breast cancer MDA-MB-468 in mouse xenograft models
Authors: Zhao Chunmei , Marella Mathieu , Zimmerman Susan , Huang Lei , Shepard H. Michael , Huang Zhongdong
Published: August 2015

Hyaluronan (also known as hyaluronic acid or HA) is a nonsulfated glycosaminoglycan in the extracellular matrix. Elevated levels of HA in the tumor microenvironment have been associated with poor prognosis of several human cancers, including pancreatic, breast, colon and prostate. In many cases of breast cancer, HA is found to be associated with the stromal compartment. To understand the interaction between tumor cells and HA containing stromal compartment, we engineered a HA-high stromal cell line by overexpressing the human HAS3 gene in Balb/c 3T3 fibroblast cells. In vitro, the 3T3/HAS3 cells produced and secreted HA, which was shown to bind to the HA-low/CD44-high breast cancer cell line MDA-MB-468 at the cell surface. When co-grafted with MDA-MB-468 cells in mice, 3T3/HAS3 cells promoted the in vivo growth of MDA-MB-468 cells. Furthermore, depletion of HA with PEGPH20 (a pegylated form of the recombinant human PH20 protein) significantly inhibited the growth of MDA-MB-468 cells co-grafted with 3T3/HAS3 cells, suggesting that the HA provided by 3T3/HAS3 cells is critical for the growth of MDA-MB-468 cells in vivo. Immunohistochemical analysis of tumor xenograft samples showed that HA-low MDA-MB-468 cells were surrounded by HA-high stromal cells, resembling the tumor morphology observed in certain breast cancer patients. To model for breast cancers with tumor cell-associated HA, we overexpressed the human HAS3 gene directly in MDA-MB-468 cells. The in vivo growth of MDA-MB-468 was significantly enhanced by HAS3 overexpression. Depletion of HA by PEGPH20 synergized with Abraxane and improved its anti-cancer efficacy in the MDA-MB-468/HAS3 xenograft model compared to PEGPH20 and Abraxane alone. Taken together, we have developed tumor xenograft models that mimic HA-high breast cancers and can be used to test the pharmacological activity of anticancer agents. Further characterization of these models will provide insights into the understanding of the mechanisms by which increased levels of HA and the associated changes in the tumor microenvironment promote the disease progression in breast cancer and how depletion of HA can interfere with this process and synergize with chemotherapies to inhibit tumor progression.

Citation Format: Chunmei Zhao, Mathieu Marella, Susan Zimmerman, Lei Huang, H. Michael Shepard, Zhongdong Huang. Hyaluronan-dependent growth of human triple negative breast cancer MDA-MB-468 in mouse xenograft models. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2392. doi:10.1158/1538-7445.AM2015-2392
Abstract 2393: PDAC cells release BAG3 that activates a paracrine loop with stromal macrophages
Authors: Rosati Alessandra , Basile Anna , D'Auria Raffaella , d'Avenia Morena , De Marco Margot , Falco Antonia , Festa Michelina , Guerriero Luana , Iorio Vittoria , Pascale Maria , Franco Renato , Arra Claudio , Barbieri Antonio , Rea Domenica , Menichini Giulio , Hahne Michael , Bijlsma Marteen , Barcaroli Daniela , Tuveson David A. , Todoric Jelena , Karin Michael , De Laurenzi Vincenzo , Turco Maria Caterina
Published: August 2015

Interactions between cancer cells and stromal cells are critically involved in tumor formation, progression and development of metastasis. Here we report for the first time that human pancreatic adenocarcinoma (PDAC) cells secrete BAG3 that binds and activates macrophages, inducing their activation and the secretion of pancreatic cancer- supporting factors. We also identify IFITM-2 as a BAG3 receptor, by its co-precipitation with BAG3 from macrophage cell membrane and by impairment of BAG3- induced activation in IFITM-2- silenced macrophages. Finally we show the importance of this pathway in vivo since in nu/nu mice carrying orthotopic xenografts of human PDAC (MIA PaCa-2) cells, BAG3 sequestration by an anti-BAG3 antibody results in reduced tumor growth and prevents metastastasis formation. In conclusion we have identified a novel paracrine loop involved in PDAC growth and metastatic spreading and shown that its pharmacological blockage with an anti-BAG3 antibody has therapeutic potential.

Citation Format: Alessandra Rosati, Anna Basile, Raffaella D'Auria, Morena d'Avenia, Margot De Marco, Antonia Falco, Michelina Festa, Luana Guerriero, Vittoria Iorio, Maria Pascale, Renato Franco, Claudio Arra, Antonio Barbieri, Domenica Rea, Giulio Menichini, Michael Hahne, Marteen Bijlsma, Daniela Barcaroli, David A. Tuveson, Jelena Todoric, Michael Karin, Vincenzo De Laurenzi, Maria Caterina Turco. PDAC cells release BAG3 that activates a paracrine loop with stromal macrophages. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2393. doi:10.1158/1538-7445.AM2015-2393
Abstract 24: The phosphorylation of p53 at serine 46 is essential to induce cell death through palmdelphin in response to DNA damage
Authors: Dashzeveg Nurmaa Khund , Yoshida Kiyotsugu
Published: August 2015

Tumor suppressor p53 plays a pivotal role in cell cycle arrest, DNA repair, and apoptosis in response to DNA damage. Promoter selectivity of p53 depends mainly on post-translational modification. Notably, the apoptotic function of p53 is related to its phosphorylation at serine-46 (ser46) to promote pro-apoptotic genes. However, little is known about the pro-apoptotic genes induced by Ser46 phosphorylation. Our research achieved to investigate the pro-apoptotic genes induced by p53 in a phospho-ser46-specific manner using microarray and ChIP sequencing in human cancer cell lines. As a result, palmdelphin (PALMD), an isoform of paralemmin protein, was strongly elicited from the phosphorylation of ser46. The mRNA and protein expression of PALMD increased only in wild type p53 transfected cells, but not in ser46-mutated cells. Importantly, PALMD moved to the nucleus in response to DNA damage and the apoptotic function of PALMD was tightly exerted with localization into nucleus. Interestingly, down-regulation of PALMD by siRNA resulted in necroptosis-like cell death through ATP depletion. Moreover, we found vimentin as a PALMD interacting protein and the depletion of vimentin increased PALMD level to accelerate apoptosis. These results demonstrate that p53 regulates cell death fate (apoptosis or necroptosis-like cell death) through promoting PALMD expression in a phospho-ser46-specific manner in response to DNA damage.

Citation Format: Nurmaa Khund Dashzeveg, Kiyotsugu Yoshida. The phosphorylation of p53 at serine 46 is essential to induce cell death through palmdelphin in response to DNA damage. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 24. doi:10.1158/1538-7445.AM2015-24
Abstract 2418: A comparison of NVP-AUY-922 (AUY) and Geldenamycin (G) in human tumor primary culture microspheroids
Authors: Nagourney Robert Alan , Bernard Paula J. , Francisco Federico , Cule Meghan , Wexler Ryan , Evans Steven S.
Published: August 2015

Introduction: Molecular chaperone heat shock protein 90 (HSP 90) maintains the stability and function of client proteins essential for malignant transformation. The ansamycin Geldenamycin (G) and its derivative 17-AAG are potent HSP90 inhibitors with activity observed in human tumors. The resorcinol-based HSP90 inhibitor AUY offers advantages with regard to solubility & DT-diaphorase independence. To evaluate and compare the activity of AUY & G we conducted ex vivo analysis of programmed cell death (EVA/PCD™) on microspheroids isolated from fresh human tumor specimens. Methods: The EVA/PCD™ method as previously reported (Nagourney, RA Anticancer Res. 2012) isolates microspheroids of desired size by mechanical & enzymatic disaggregation followed by precise density centrifugation. Drug activity is measured by delayed loss of membrane integrity & ATP content (luciferase). Lethal concentration (LC50) values are interpolated from 5-point dose response curves and compared by modified Z-Score. Concentrations ranges for AUY were 6.25-100 uM and for G 1.25-20 uM. Results: AUY and G activity compared in 22 parallel analyses by Pearson Moment revealed a correlation coefficient R = 0.59 (p <0.005). Activities for AUY & G by disease were generally similar favoring Heme >Sarcoma >Melanoma >Ovary>NSCLC>Breast. ERBB2 (+) breast appeared more sensitive as did several EGFr mutation (+) NSCLC specimens. Metachronous assays conducted in 3 EGFr (+) NSCLC pts revealed activity for G following Erlotinib failure. Additional studies with AUY alone and in combination are underway. Conclusions: i) HSP-90 inhibitors are active in human tumor primary cultures ii) AUY and G activity correlate iii) HSP90 inhibitor activities reveal disease & patient-specific profiles iv) EVA/PCD™ analyses could facilitate the development of clinical strategies for the use of HSP90 inhibitors. Supported by The Vanguard Cancer Foundation & The Nagourney Institute. NVP-AUY-922 was the kind gift of Novartis AG.

Citation Format: Robert Alan Nagourney, Paula J. Bernard, Federico Francisco, Meghan Cule, Ryan Wexler, Steven S. Evans. A comparison of NVP-AUY-922 (AUY) and Geldenamycin (G) in human tumor primary culture microspheroids. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2418. doi:10.1158/1538-7445.AM2015-2418
Abstract 2422: Pan-pim kinases inhibitor, AZD1208 suppresses tumor growth and synergistically interacts with an AKT inhibitor in gastric cancer cells
Authors: Lee Miso , Lee Kyung-Hun , Min Ahrum , Kim Jungeun , Im Seock-Ah , Kim Seon-Gyeong , Jang Hyemin , Yang Yae-Won , Kim Tae-Yong , Han Sae-Won , Oh Do-Youn , Kim Tae-You , Bang Yung-Jue
Published: August 2015

Introduction: Pim kinases are highly conserved serine/threonine kinases that control proliferation and survival pathways in cancer cells. Different expression patterns of each isoforms (Pim-1, Pim-2, and Pim-3) have been observed in various types of human cancer including gastric cancer. AZD1208 is a potent and selective inhibitor that affects all three isoforms of Pim. We investigated the effect of AZD1208 as a single agent or in combination with an Akt inhibitor on the growth and cell death in gastric cancer cells.

Materials and Methods: The antitumor activity of AZD1208 with/without an Akt inhibitor was evaluated in a large panel of gastric cancer cell lines through growth inhibition assay. The underlying mechanism was also examined by western blotting, immunofluorescence assay (IFA), and cell cycle analysis.

Results: Direct substrates of Pim kinases were downregulated by the treatment with AZD1208, but we could not find any reduction of cell viability in short-term cell cultures. In contrast, cell viability decreased significantly in long-term cultures. Light chain 3B (LC3B), a marker for autophagy, increased in sensitive cells in dose dependent manner with AZD1208 treatment, which suggest that the growth inhibition effect of AZD1208 was achieved through autophagy, but not through apoptosis. Moreover, we found that ATM and Chk2, two critical components of the DNA repair pathway, were activated in an AZD1208-resistant cell line. We also confirmed that the combination of an Akt inhibitor with AZD1208 produced a highly synergistic effect in gastric cancer cell lines.

Conclusion: AZD1208 induced cell death through autophagy in gastric cancer cells. Additionally, the combination of AZD1208 with an Akt inhibitor shows synergistic antitumor effects.

Citation Format: Miso Lee, Kyung-Hun Lee, Ahrum Min, Jungeun Kim, Seock-Ah Im, Seon-Gyeong Kim, Hyemin Jang, Yae-Won Yang, Tae-Yong Kim, Sae-Won Han, Do-Youn Oh, Tae-You Kim, Yung-Jue Bang. Pan-pim kinases inhibitor, AZD1208 suppresses tumor growth and synergistically interacts with an AKT inhibitor in gastric cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2422. doi:10.1158/1538-7445.AM2015-2422
Abstract 2444: Directed evolution strategy for generating of novel zinc finger peptides with affinity for gapped DNA
Authors: Plaskon Dylan , Guerra Rachel M. , McGuckin Connor P. , Lopez Ruiz Vania , Sheehan Colin T. , Weeks Ryan A. , Cincotta Dylan , Rice Kevin P.
Published: August 2015

A significant fraction of oncologists’ chemotherapeutic arsenal consists of agents that cause DNA damage. Repair proteins that recognize aberrant DNA structural features mitigate this damage and thus the efficacy of such anticancer drugs. DNA damage recognition is also crucial for genomic stability, and thus avoidance of carcinogenesis, in healthy cells. The DNA repair enzymes poly(ADP-ribose) polymerase (PARP) and DNA ligase III use similar zinc finger motifs to facilitate this sequence-independent DNA recognition. Reported here is a strategy to model these protein-DNA interactions using small proteins. Proteins with high affinity for gapped DNA are selected from highly diverse libraries of proteins, based on PARP-like zinc finger domains, using phage display. These populations were engineered at the DNA level, using two parallel approaches, with built-in randomization then cloned into viral chromosomes. The de novo approach involved synthetic oligonucleotides with specific random codons. In addition, the gene encoding the second PARP zinc finger was cloned from human cells and subjected to 30 cycles of error-prone PCR with a mutation rate of 0.02 per nucleotide. From each approach, a library of approximately 10 billion distinct phage-displayed variants is exposed to immobilized DNA molecules featuring a gapped DNA construct. Selected molecules are either identified by DNA sequencing or subjected to further selection after amplification in bacterial culture. A preliminary selection against nicked DNA yielded a single, truncated peptide after four rounds of selection. In subsequent experiments, Illumina sequencing will identify consensus sequences that will be cloned into plasmids appropriate for expression in bacteria. Molecules discovered by this strategy will help illuminate the structure-function relationships of proteins that recognize distinct DNA structures and may lead to new anticancer approaches.

Citation Format: Dylan Plaskon, Rachel M. Guerra, Connor P. McGuckin, Vania Lopez Ruiz, Colin T. Sheehan, Ryan A. Weeks, Dylan Cincotta, Kevin P. Rice. Directed evolution strategy for generating of novel zinc finger peptides with affinity for gapped DNA. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2444. doi:10.1158/1538-7445.AM2015-2444
Abstract 2445: DNA recognition by XR5944, a novel bis-intercalator and potent anticancer drug
Authors: Lin Clement , Mathad Raveendra I. , Sidell Neil , Yang Danzhou
Published: August 2015

DNA is a major target for drugs used in cancer therapy. However, DNA interactive chemotherapeutics are limited by adverse effects due to their poor selectivity. The bis-phenazine compound XR5944 is a DNA bis-intercalator and potent anticancer drug which reached phase I clinical trials. The DNA binding mode and mechanism of XR5944 are unique, allowing it to recognize and bind the estrogen response element (ERE) sequence to inhibit ERα activity and making it highly effective against ER-positive breast cancer in vitro. Understanding XR5944's novel mechanism of DNA recognition may allow the further development of anti-cancer agents capable of overcoming drug resistance to current anti-estrogen treatments by directly targeting transcriptional control, bypassing the hormone-receptor complex currently targeted by anti-estrogen treatments. In this study, we used nuclear magnetic resonance (NMR) spectroscopy to determine the structure of XR5944 in complex with its preferred DNA duplex sequence identified its binding mode. The structure of the 2:1 complex of XR5944 with the naturally occurring TFF1-ERE exhibits several unexpected features. Our NMR structure shows the two phenazine moieties are well stacked and the carboxamide amino linker lies in the major groove of DNA. At both binding sites in the 2:1 complex, XR5944 intercalates strongly at one site but weakly at the other. The binding sites within a native promoter sequence appear to be context- and sequence- dependent. Taken together, our results highlight that the DNA binding of a bis-intercalator is different from the simple addition of two single intercalation sites. Our study suggests that improved XR5944 derivatives targeting EREs may be designed through optimization of aminoalkyl linker and intercalation moieties.

Citation Format: Clement Lin, Raveendra I. Mathad, Neil Sidell, Danzhou Yang. DNA recognition by XR5944, a novel bis-intercalator and potent anticancer drug. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2445. doi:10.1158/1538-7445.AM2015-2445
Abstract 2452: Deorphanizing TLX: Implications for treatment of glioblastomas
Authors: Benod Cindy C. , Villagomez Rosa , Webb Paul
Published: August 2015

Nuclear receptors (NRs) are important ligand-dependent transcriptional factors. Presently, no natural or synthetic ligand has been identified for a large group of so- called “orphan” NRs. The orphan NR tailless (TLX, NR2E1), a transcriptional repressor, is a major player in neurogenesis and emerging evidence indicates that it is an excellent target to treat Neural Stem Cell (NSC) derived brain tumors and glioblastomas. Indeed, several groups hypothesized that small molecules de-repressing TLX activity in glioblastoma cells should slow tumor progression and invasiveness by inducing the cyclin-dependent kinase inhibitor p21 and the tumor suppressor pten. Until recently, no chemical probes to modulate TLX activity to test this hypothesis were available, and it was not clear whether TLX was druggable. Our homology models of the TLX ligand binding domain (LBD) suggest that TLX belongs to an emerging class of NRs that lack two LBD helices and fold into an auto-repressed conformation. While our models suggests that TLX could harbor a ligand binding pocket, the consequences of its unusual organization for small molecule development were unknown. We used a medium throughput screening strategy to assess TLX ligand binding capacity. We investigated direct binding of 20,000 compounds to purified human TLX protein and verified interactions with a secondary (orthogonal) assay. We then assessed effects of verified binders on TLX activity. As a result, we reported three compounds that bind to TLX with affinities in the high nanomolar to low micromolar range and enhance TLX transcriptional repressive activity. Based on this study, we could conclude that TLX is druggable. We are now investigating how to de-repress TLX transcriptional activity using derivatives of these small molecules. We are imaging the mode of binding of the three identified ligands and discovering surfaces which bind coregulators of TLX in glioblastomas. This knowledge will allow us to devise strategies to chemically modify novel TLX ligands to disrupt coregulator interactions and to obtain the desirable biological activities. A first generation of novel analogues is currently being tested. In this presentation we will describe ongoing Structure-Activity Relationship studies to identify new specific TLX ligands able to de-repress TLX transcriptional activity.

Citation Format: Cindy C. Benod, Rosa Villagomez, Paul Webb. Deorphanizing TLX: Implications for treatment of glioblastomas. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2452. doi:10.1158/1538-7445.AM2015-2452
Abstract 2463: Enhanced anti-tumor activity of an Auristatin-based antibody-drug conjugate in combination with PI3K/mTOR inhibitors or taxanes: Translational implications and mechanistic insights
Authors: Sapra Puja , Shor Boris , Dougher Maureen , Kahler Jennifer , Mack Michelle , Xu Jane , Lu Shuyan , Melamud Eugene , Wang Fang , Rosfjord Edward
Published: August 2015

Targeted treatment with antibody-drug conjugates (ADCs) can lead to dramatic regressions of solid tumors; combination therapies with the ADCs that could potentially help achieve long-term disease control remain largely unexplored. The aim of the study is to investigate most promising combination regimens of auristatin-based conjugates in preclinical models of cancer.

A tool ADC, an auristatin-based anti-5T4 antibody conjugate (5T4-ADC) and permeable auristatin analogs were combined with dual PI3K/mTOR catalytic site inhibitor PF-05212384 (PF-384) or taxanes in a panel of common cancer cell lines of breast, lung or ovarian origin. Drug combinations were tested for their effects in vitro on cell viability, apoptosis, cell cycle or modulation of PI3K/mTOR pathway markers. Anti-tumor efficacy of selected combinations was also evaluated in a 5T4-positive human breast or lung tumor xenografts in vivo.

Remarkably, ADC and auristatin analogs resulted in synergistic or additive effects on cell cytotoxicity when combined with PF-384 or with taxanes in vitro. ADC/PF-384, auristatin/PF-384 and ADC/Paclitaxel (PTX), auristatin/PTX combinations showed enhanced induction of apoptosis and selective attenuation of the downstream phospho-markers of the PI3K/mTOR pathway. Quantitative proteomic analysis of cells treated with auristatin-based agents and PF-384 alone or in combination revealed novel and unique effects on key components of mRNA translation, including translation initiation or elongation factors. In human lung or breast cancer xenograft models, dual targeting with 5T4-ADC/PF-384 or 5T4-ADC/PTX produced substantially greater antitumor effects with longer average survival as compared to monotherapy treatments.

Our results provide strong rationale for combining 5T4-ADC with PI3K/mTOR pathway inhibitors or taxanes. New biological insights into molecular mechanisms underlying synergistic effects of ADC - drug combinations suggest/reveal that synergies are mediated by payload's mode of action. These findings can be applicable to several ADCs employing microtubule inhibitors that are undergoing clinical evaluation.

Citation Format: Puja Sapra, Boris Shor, Maureen Dougher, Jennifer Kahler, Michelle Mack, Jane Xu, Shuyan Lu, Eugene Melamud, Fang Wang, Edward Rosfjord. Enhanced anti-tumor activity of an Auristatin-based antibody-drug conjugate in combination with PI3K/mTOR inhibitors or taxanes: Translational implications and mechanistic insights. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2463. doi:10.1158/1538-7445.AM2015-2463
Abstract 247: Comparing radiation therapy and ipilimumab to ipilimumab alone in metastatic melanoma patients
Authors: Patel Kirtesh R. , Oliver Daniel E. , Okwan-Dadu Derick , Liu Yuan , Kudchadkar Ragini R. , Lawson David H. , Khan Mohammad K.
Published: August 2015

Purpose/Objective:

With evidence suggesting ipilimumab and intracranial stereotactic radiosurgery (SRS) improves survival compared to SRS alone, we compared toxicity, response rates (RRs), and outcomes of metastatic melanoma patients receiving radiation (RT) and ipilimumab to ipilimumab alone.

Methods and Materials:

We reviewed records of metastatic melanoma patients receiving ipilimumab 3mg/kg between 2010-2014. RRs, measured by immune RECIST criteria, and toxicity were compared by Fischer's exact text. Overall survival (OS) was estimated by the Kaplan Meier method.

Results:

61 patients received ipilimumab, with 35 (57.4%) also receiving radiation within 4 months of ipilimumab. The radiation cohort was similar at baseline except for greater systemic burden of disease (82.9% vs. 42.3%, p = 0.005), higher dexamethasone use (14.3% vs. 0%, p = 0.048), and more brain involvement (74.3% vs. 0% p<0.001). 92.3% of brain metastases received SRS. Grade 3 toxicity was not statistically different between cohorts (5.9% vs. 20.0%, p = 0.113); one grade 4 was experienced (1.6%), while no grade 5 occurred. While the ipilimumab alone group demonstrated a trend toward higher 1-year OS (49.4% vs. 73.2%, p = 0.090), the cohort did not have any patients with brain metastases; therefore, comparing only patients with extra-cranial metastases, 1-year OS was similar (76.2% vs. 73.2%, p = 0.587). RR between both cohorts was similar (20.0% vs. 11.5%, p = 0.494). Pre-ipilimumab absolute lymphocyte count greater than 1000 was the only significant predictor for increased RR in multivariable analysis (Odds Ratio: 8.56, 95% CI: 1.82-40.42; p = 0.007). Comparing 2-5 fractions of radiation to ipilimumab alone demonstrated a trend towards higher response rate (42.9% vs. 11.5%, p = 0.074).

Conclusion:

Despite poorer prognostic characteristics in the RT with ipilimumab cohort, toxicity, RR and OS were similar between the arms. Prospective studies investigating the ideal radiation fractionation to improve ipilimumab response rates are warranted. ALC < 1000 should be considered an exclusion criteria for these trials.

Citation Format: Kirtesh R. Patel, Daniel E. Oliver, Derick Okwan-Dadu, Yuan Liu, Ragini R. Kudchadkar, David H. Lawson, Mohammad K. Khan. Comparing radiation therapy and ipilimumab to ipilimumab alone in metastatic melanoma patients. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 247. doi:10.1158/1538-7445.AM2015-247
Abstract 2497: Immune checkpoint inhibitors enhance benefits of modified vaccinia virus Ankara to improve survival in preclinical models of cancer
Authors: Rittner Karola , Remy-Ziller Christelle , Hortelano Julie , Farine Isabelle , de Meyer Micael , Nourtier Virginie , Gantzer Murielle , Thioudellet Christine , Slos Philippe , Preville Xavier
Published: August 2015

TG4010 is a Modified Vaccinia virus Ankara (MVA) expressing human interleukin 2 and the human mucin1 (MUC1) tumor associated antigen. TG4010 has demonstrated clinical benefit for advanced non small cell lung cancer patients in combination with standard of care chemotherapy in two phase 2 randomized and controlled clinical trials (NCT00415818 and NCT1383148).

Immunotherapy based on the use of immune checkpoint blockers such as anti PD-1 and anti PD-L1 has also demonstrated efficacy in phase 2 trials. Hence, the combination of both approaches appears to be of great interest considering the high unmet medical need of this pathology. We developed experimental primary tumor and lung metastasis models to evaluate the rationale of combining both approaches at the preclinical level. Using two CT26 cell lines expressing different target antigens (β-galactosidase and MUC1) we evaluated the impact on overall survival of combined MVA-based and immune checkpoint-based immunotherapies. Synergistic increase in overall survival was observed in the therapeutic CT26-CL25 primary tumor and lung metastasis models upon treatment of mice with the combination of MVA-βgal and anti CTLA4 or anti PD-1 in comparison with either treatment alone. We provide evidence that TG4010 synergized with immune checkpoint inhibitors to increase overall survival in the therapeutic CT26-MUC1 tumor models in comparison with either treatment administrated independently. These observations were associated with an increase in the frequency and the quality of antigen-specific tumor infiltrating CD8+ T cells.

These studies pave the way for the evaluation of combinatorial therapies including TG4010 and immune checkpoint blockers in the clinic.

Citation Format: Karola Rittner, Christelle Remy-Ziller, Julie Hortelano, Isabelle Farine, Micael de Meyer, Virginie Nourtier, Murielle Gantzer, Christine Thioudellet, Philippe Slos, Xavier Preville. Immune checkpoint inhibitors enhance benefits of modified vaccinia virus Ankara to improve survival in preclinical models of cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2497. doi:10.1158/1538-7445.AM2015-2497
Abstract 2500: Identification of promiscuous oncofetal antigen (IMP-3)-derived long peptides, bearing both Th cell and CTL epitopes
Authors: Hirayama Masatoshi , Yuno Akira , Tomita Yusuke , Sayem Mohammad Abu , Tsukamoto Hirotake , Irie Atsushi , Senju Satoru , Yoshitake Yoshihiro , Fukuma Daiki , Shinohara Masanori , Yuba Eiji , Kono Kenji , Yoshida Koji , Nakamura Yusuke , Nakayama Hideki , Nishimura Yasuharu
Published: August 2015

We recently identified CTL epitopes derived from an oncofetal antigen, insulin-like growth factor II mRNA-binding protein 3 (IMP-3) which was frequently overexpressed in head-and-neck cancers (HNCs) and lung cancers, but not in many normal adult organs, by using genome-wide cDNA microarray analyses. Several phase I/II clinical trials using IMP-3-derived short peptides (SPs) vaccination against several types of malignant tumor are ongoing. Recently we reported the phase I/II clinical trial of multiple tumor-associated-antigen (TAA)-derived SPs vaccinations including IMP-3-SP for advanced HNC patients. In this trial, we observed the vaccinated SPs-specific CTL responses and the prolongation of overall survival of HNC patients (Clin Cancer Res; Nov. 12, 2014 in press). In order to further develop peptides-based cancer immunotherapy, we attempted to identify IMP-3-derived long peptides (LPs) containing both CTL and Th cell epitopes in this study. We successfully identified two promiscuous IMP-3-derived LPs, and one of them encompasses two natural CTL epitopes, and these LPs can stimulate IMP-3-LP-specific Th1 cells restricted by 7 frequent HLA class II molecules. We confirmed that Th cells induced by two LPs responded to autologous dendritic cells (DCs) loaded with IMP-3 protein, suggesting that these IMP-3-derived LPs were possibly naturally processed from IMP-3 protein and presented by DCs. We also demonstrated that one of the IMP-3-derived LPs could cross-prime IMP-3-SP-specific CTLs in vitro in human and in vivo in HLA-A2 transgenic mice. The same LP encapsulated in newly developed pH-sensitive liposome, that can deliver LPs from endosome to cytoplasm, was also found to be efficiently cross presented in vitro to stimulate IMP-3-SP-specific human CTLs. Furthermore, we could induce IMP-3-LP-specific Th cells from a HNC patient vaccinated with an IMP3-derived SP. Immune response to these LPs in many other HNC patients is now under investigation. Taken together, IMP-3-derived LPs may be applicable to cancer immunotherapy.

Citation Format: Masatoshi Hirayama, Akira Yuno, Yusuke Tomita, Mohammad Abu Sayem, Hirotake Tsukamoto, Atsushi Irie, Satoru Senju, Yoshihiro Yoshitake, Daiki Fukuma, Masanori Shinohara, Eiji Yuba, Kenji Kono, Koji Yoshida, Yusuke Nakamura, Hideki Nakayama, Yasuharu Nishimura. Identification of promiscuous oncofetal antigen (IMP-3)-derived long peptides, bearing both Th cell and CTL epitopes. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2500. doi:10.1158/1538-7445.AM2015-2500
Abstract 2524: Combination with vorinostat overcomes ABT-263 resistance of small cell lung cancer
Authors: Nakajima Wataru , Hicks Mark A. , Sharma Kanika , Le Ngoc , Krystal Geoffrey W. , Harada Hisashi
Published: August 2015

Lung cancer is the most common cause of cancer related mortality worldwide, with small cell lung cancer (SCLC) representing 15% of cases, accounting for 30,000 new cases in the US each year. While SCLC is initially a highly chemotherapy-responsive disease, relapse and progressive development of chemotherapy resistance is the rule. One promising approach to overcome the therapeutic resistance would be to utilize agents targeting molecular abnormalities regulating resistance to apoptosis.

Tumor cell death induced by chemotherapy or lack of appropriate cellular survival signals is mediated by the BCL-2 family-dependent mitochondrial apoptotic pathway. We and others have shown that the pro-survival member BCL-2, as well as BCL-XL and MCL-1, is overexpressed in SCLC. BH3 mimetic antagonists have been developed to block the function of pro-survival BCL-2 family members. ABT-737 and its orally available derivative ABT-263 bind to and block BCL-2 and BCL-XL, but not MCL-1 function. Although SCLC is the only non-hematologic malignancy against which ABT-737/ABT-263 are effective as single agents, the sensitivity of SCLC to these drugs varies over a broad range in vitro and in clinical trials. We have shown in a model SCLC system that expression of Noxa, a BH3-only pro-apoptotic BCL-2 family protein, is a critical determinant of ABT-737 sensitivity, demonstrating that Noxa specifically binds to and recruits MCL-1 from the cytosol to the mitochondria.

Recent integrative genome analysis in SCLC implicates histone modification as a major feature of SCLC. It has also been demonstrated that Noxa is transcriptionally activated by HDAC inhibitors. Thus, we hypothesized that alteration of histone modification by a HDAC inhibitor, vorinostat could induce Noxa to enhance cell death by ABT-737/263 treatment. We have found that combination of ABT-263 and vorinostat efficiently induces apoptosis in a variety of SCLC cell lines, even in the ABT-263 resistant cells. Cell death induced by combined treatment is Noxa- and/or BIM-dependent in some cell lines but in others appears to be mediated by an alternative mechanism. These results suggest that combination of HDAC inhibitors and BCL-2 inhibitors could be an alternative effective regimen for SCLC treatment.

Citation Format: Wataru Nakajima, Mark A. Hicks, Kanika Sharma, Ngoc Le, Geoffrey W. Krystal, Hisashi Harada. Combination with vorinostat overcomes ABT-263 resistance of small cell lung cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2524. doi:10.1158/1538-7445.AM2015-2524
Abstract 2541: Preclinical results of SGN-CD19A in combination with R-ICE or R-CHOP in non-Hodgkin lymphoma models
Authors: Van Epps Heather A. , Klussman Kerry , Anderson Martha , Zeng Weiping , Olson Devra , Ryan Maureen , Albertson Tina , Law Che-Leung
Published: August 2015

SGN-CD19A is an antibody drug conjugate (ADC) that recognizes CD19, a B-cell specific marker expressed in B-cell malignancies including non-Hodgkin lymphoma (NHL). SGN-CD19A is currently in a phase I clinical trial for adult patients with relapsed refractory B-cell NHL (CT.gov NCT01786135) in which it has shown evidence of single-agent activity (1). This ADC binds CD19, internalizes, and releases cys-mcMMAF, which ultimately induces apoptosis in targeted cells (2). Lymphoma tumor xenografts treated with SGN-CD19A show growth delay in a dose dependent manner. Here we show that SGN-CD19A in combination with standard of care [rituximab/ifosfamide/carboplatin/etoposide (R-ICE), rituximab/cyclophosphamide/doxorubicin/vincristine/prednisone (R-CHOP), or components] exceeds the activity of SGN-CD19A alone and results in impressive anti-tumor activity in multiple xenograft models. It was notable that in some xenograft models, SGN-CD19A + R-CHOP or SGN-CD19A + R-ICE yielded activity that was similar to SGN-CD19A plus rituximab alone. This strong interaction between rituximab and SGN-CD19A was modeled in vitro. SGN-CD19A synergized with rituximab, in the absence of cross-linking, to cause decreased cell viability in NHL cell lines. These data suggest that cell autonomous signaling contributes to the unique interaction between rituximab and SGN-CD19A. Our in vivo and in vitro data support R-CHOP, R-ICE, or rituximab as viable combination therapies for NHL patients with SGN-CD19A.

1) Uma Borate et al. A first-in-human phase 1 study of the antibody-drug conjugate SGN-CD19A in relapsed or refractory B-lineage acute leukemia and highly aggressive lymphoma. Blood 2013 122:1437

2) Che-Leung Law et al. Preclinical characterization of an auristatin-based anti-CD19 drug conjugate, SGN-19A. Abstract number 625. In: Proceedings of the 102th Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL.

Citation Format: Heather A. Van Epps, Kerry Klussman, Martha Anderson, Weiping Zeng, Devra Olson, Maureen Ryan, Tina Albertson, Che-Leung Law. Preclinical results of SGN-CD19A in combination with R-ICE or R-CHOP in non-Hodgkin lymphoma models. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2541. doi:10.1158/1538-7445.AM2015-2541
Abstract 2549: Tyrosyl-DNA phosphodiesterase 1 (TDP1) is critical for the repair of DNA breaks induced by sapacitabine, a nucleoside antimetabolite in clinical trials targeted to ATM- and BRCA-deficient tumors
Authors: Al Abo Muthana , Liu Xiaojun , Plunkett William , Pommier Yves
Published: August 2015

2′-C-cyano-2′-deoxy-1-β-D-arabino-pentofuranosylcytosine (CNDAC) is a nucleoside analogue and the active metabolite of the anticancer drug, sapacitabine. The cytotoxic activity of CNDAC is achieved by incorporation of its nucleoside triphosphate metabolite into genomic DNA during replication, which subsequently undergoes beta-elimination that generates a single-strand break with 3′-end blocking DNA lesion. Subsequent DNA replication converts the nick into a double strand break. Earlier investigations demonstrated that cells lacking homologous recombination function are sensitized 20- to 100-fold to CNDAC. Because tyrosyl-DNA phosphodiesterase 1 (TDP1) efficiently hydrolyzes 3′-blocking ends, we tested its role in the repair of CNDAC-induced DNA lesions and the potential cellular tolerance to CNDAC. Here we show that cells lacking TDP1 (TDP1-/- DT40 cells) exhibited marked hypersensitivity to CNDAC indicating the importance of TDP1 for the repair of CNDAC-induced DNA damage. Although the 3′-end blocking DNA lesions caused by another arabinosyl-nucleoside analog, cytosine arabinoside (cytarabine, AraC) and the topoisomerase I inhibitor camptothecin (CPT) are also repaired by TDP1, inactivation of homologous recombination, including BRCA1 and BRCA2, rendered cells hypersensitive to CNDAC and CPT but not to AraC. On the other hand, cells lacking PARP1/2 were hypersensitive to CPT only. Consistent with earlier findings, DT40 cells deficient in BRCA1, BRCA2, FANCD2, and ATM were sensitized to CNDAC. Thus, the present study has identified TDP1 as an additional mechanism that contributes to the repair of CNDAC-induced DNA lesions. It also demonstrates the differential involvement of DNA repair pathways that underlie the resistance to CNDAC, AraC and camptothecins, and provides a rationale for using sapacitabine to treat various types of cancers with preexisting defects in DNA repair pathways.

Citation Format: Muthana Al Abo, Xiaojun Liu, William Plunkett, Yves Pommier. Tyrosyl-DNA phosphodiesterase 1 (TDP1) is critical for the repair of DNA breaks induced by sapacitabine, a nucleoside antimetabolite in clinical trials targeted to ATM- and BRCA-deficient tumors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2549. doi:10.1158/1538-7445.AM2015-2549
Abstract 2559: Optimisation of EGFR TKI efficiency wild-type EGFR lung cancer
Authors: Raimbourg Judith , Cabart Mathilde , Joalland Marie-Pierre , Decaudin Didier , Deplater Ludmilla , Lanoe Didier , Douillard Jean-Yves , Bennouna Jaafar , Vallette François , Lalier Lisenn
Published: August 2015

Background : Lung cancer is the first cause of cancer death worldwide. EGFR tyrosine kinase inhibitors (EGFR-TKI) have improved the survival of patient harboring EGFR activating mutations. Besides, EGFR-TKIs have shown clinical activity for patients with wild type EGFR (wtEGFR) tumors as maintenance treatment and for a fraction of them as second line treatment. These observations impel us to objective and document the mechanisms implicated in order to optimize the use of EGFR-TKI in the treatment of wtEGFR lung cancer.

Methods : In vitro experiments rely on lung cancer cell lines expressing either wtEGFR or mutated EGFR. Their sensitivity to erlotinib in control conditions or short after a sublethal cisplatin treatment was studied. In vitro results were validated on lung patients-derived xenografts (PDX) with four wtEGFR human adenocarcinomas.

Results : Cisplatin pretreatment enhances erlotinib toxicity in wtEGFR cells (providing its robust expression) but not in EGFR-mutated cells. Cisplatin priming increases erlotinib toxicity either through apoptosis or autophagy depending on the cell line. This sensitization correlates with an increase in EGFR expression and phosphorylation and a raise in AKT and Erk phosphorylation. The sensitization is also observed during long-term cisplatin treatment in a cisplatin-resistant subpopulation, together with concomitant EGFR pathway activation.

The in vivo experiments conducted in PDX confirm that cisplatin pretreatment potentiates erlotinib in three of the four wtEGFR lung tumors models.

Of note, the sensitization to erlotinib occured independently from KRas status.

Conclusion : The sensitivity of the wtEGFR lung cancer cells and lung cancer xenografts to erlotinib is enhanced by cisplatin pretreatment, whatever the type of induced cell death. Cisplatin induces activation of EGFR and his downstream kinases AKT and Erk. This sensitization is independent from the tumor K-Ras status. EGFR phosphorylation could be a potential marker of this sensitization and might be predicitive of the optimal efficiency of EGFR TKI. In vivo validation of this marker is still ongoing.

This study was supported by Roche laboratory and by the foundation for medical research.

Citation Format: Judith Raimbourg, Mathilde Cabart, Marie-Pierre Joalland, Didier Decaudin, Ludmilla Deplater, Didier Lanoe, Jean-Yves Douillard, Jaafar Bennouna, François Vallette, Lisenn Lalier. Optimisation of EGFR TKI efficiency wild-type EGFR lung cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2559. doi:10.1158/1538-7445.AM2015-2559
Abstract 2577: Aurora kinase inhibitors require PUMA to induce apoptosis and preferentially kill KRAS-mutant colon cancer cells
Authors: Sun Jing , Knickelbein Kyle , He Kan , Chen Dongshi , Yu Jian , Zhang Lin
Published: August 2015

Aurora kinases play a key role in mitosis and are frequently overexpressed in a variety of tumor cells. Inhibition of aurora kinases results in mitotic arrest and death of cancer cells, and has been explored as an anti-cancer strategy. However, how aurora inhibition kills cancer cells is poorly understood. In this study, we found that inhibition of aurora kinases by siRNA or small-molecule inhibitors led to induction of p53-upregulated modulator of apoptosis (PUMA), a BH3-only BCL-2 family protein, in colorectal cancer cells irrespective of p53 status. Deficiency in PUMA increased polyploidy and abrogated mitochondria-mediated apoptosis induced by aurora kinase inhibitors. In response to aurora kinase inhibition, PUMA was directly activated by p65 through the canonical NF-kB pathway following AKT inhibition. Interestingly, aurora kinase inhibitors were found to preferentially kill KRAS-mutant colon cancer cells, which is associated with enhanced induction of PUMA and another BH3-only protein NOXA. Furthermore, PUMA was necessary for the chemo-sensitization and in vivo anti-tumor effects of aurora kinase inhibitors in colon cancer cells. These results suggest that PUMA induction mediates the apoptotic response to mitotic arrest imposed by aurora kinase inhibition, and may be a useful indicator for the anti-cancer activity of aurora kinase inhibitors.

Citation Format: Jing Sun, Kyle Knickelbein, Kan He, Dongshi Chen, Jian Yu, Lin Zhang. Aurora kinase inhibitors require PUMA to induce apoptosis and preferentially kill KRAS-mutant colon cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2577. doi:10.1158/1538-7445.AM2015-2577