bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 914: Age-associated neoplastic transformation of mammary stem cells
Authors: Gu Xiang , Bouamar Hakim , Pressley Kyle , Sun LuZhe
Published: July 2017

Incidence rate of breast cancer increases significantly with age. However, the mechanism of age-associated mammary tumorigenesis is unknown. Although mammary stem/progenitor cells have been proposed as the cells of origin for breast cancer, the mechanism remains largely elusive. Previously we discovered that in the old (28 to 30 month-old) mouse mammary gland, the luminal cells in the hyperplastic lesions elevated expression of CD49f, which is a basal cell marker. This led to an increased percentage of mammary stem cells (MaSCs) marked by CD49fhi in the old in comparison to the young (3 to 6 month-old). Similarly, old (>60 yr) human mammary ducts in the adjacent normal tissues from patients with breast cancer showed more hyperplastic lesions and CD49fhi luminal cells than young (<40 yr) tissues. Regenerated mammary glands by the old CD49fhi MaSCs through in vivo transplantation in cleared mammary fat pads showed more hyperplastic and dysplastic lesions than those regenerated by the young CD49fhi MaSCs, suggesting the old CD49fhi MaSCs contain transformed MaSCs. Moreover, gene set enrichment analysis of whole genome transcriptome data showed that they also have elevated expression of luminal cell specific genes and reduced expression of basal cell specific genes. Through large scale screening with flow cytometry guided by bioinformatics analysis, we found that Lin- CD24med CD49fhi CD13+ CD73- mammary epithelial cells had increased number of MaSCs. By comparing young (3 to 6 months old) and old Balb/C mice, we found that the frequency of this specific MaSCs was significantly increased by four folds in old mammary epithelial cells (young: 4%, old: 16%). In contrast, relative percentage of Lin- CD24med CD49fhi CD13- CD73+ cells significantly decreased (young: 46%, old: 16%) during aging while the CD13 and CD73 double positive or double negative subpopulations remained unchanged. CD13+ CD73- cells generated significantly many more mammospheres (around 40 spheres per 1,000 cells) in suspension culture than other three types of cells (around 2 spheres per 1,000 cells). However, there was no significant difference between the young and old in terms of sphere formation efficiency for any of the four subpopulations marked by CD13 and CD73. We are studying whether anyone of these four subpopulation from CD49fhi old cells will generate more hyperplastic and dysplastic lesions in regenerated glands than the other subpopulations as well as than the corresponding young subpopulation. Our study show that CD13 and CD73 may be the markers for the identification of tumor-initiating MaSCs.

Citation Format: Xiang Gu, Hakim Bouamar, Kyle Pressley, LuZhe Sun. Age-associated neoplastic transformation of mammary stem 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 914. doi:10.1158/1538-7445.AM2017-914
Abstract 915: Thrombomodulin expression regulates the tumor stroma differentiation of mesenchymal stem cells for controlling tumor growth
Authors: Shih Tsung-Hsien , Li Jhy-Ming , Shi Guey-Yueh , Wu Hua-Lin
Published: July 2017

Introduction: Thrombomodulin (TM), a thrombin receptor on endothelial cell surface, acts as an anti-coagulant factor in thrombin-catalyzed protein C activation and inhibits the pro-coagulant functions of thrombin. Owing to TM’s widely expression patterns on various cell types, our studies have demonstrated that beside anti-coagulation, TM also participates in controlling cell-cell adhesion, tumor growth, inflammation, angiogenesis, and atherosclerosis. However, the significance of TM expression in mesenchymal stem cells (MSCs) has never been investigated. The non-hematopoietic MSCs could specifically home into the developing tumors and becomes the active components of tumor stroma, which affects tumor’s growth, immunity, progression, and therapeutic resistance. Recently, we investigated the role of TM on the tumor microenvironment differentiation of MSCs for establishing the active stroma that assists tumor growth.

Materials & methods: Normal and TM gene-targeting transgenic mice-isolated bone marrow-derived MSCs were used as the research models to investigate the expressing significance of TM on MSC’s biological activities and differentiations during mouse melanoma B16F10 cell’s conditioning in vitro and in vivo.

Results: Our data showed that MSC's TM expression was low in the quiescent state but was up-regulated while treating with B16F10 cell’s conditioned medium in the mechanism of plate-derived growth factor signaling dependence. Accordingly, using conditional gene knockout strategy, under the condition of tumor cell other than normal culture resulted in that TM gene knockout significantly affected MSC’s proliferation, migration, interleukin-6 secretion, angiogenic activity, and tumor-associated fibroblast differentiation in vitro. Furthermore, TM knockout notably reduced the capacity of MSCs on regulating the growth, vasculogenesis, and active stroma establishment of B16F10 melanoma xenograft in vivo.

Conclusion: These results indicate that the secretion of tumor-associated plate-derived growth factor is a critical event for MSC’s TM expression that controls MSC’s stroma differentiation for developing active tumor microenvironment, which promotes tumor progression. This study further suggests that the modulation of TM expression on MSCs has the therapeutic potential via diminishing the establishment of functional tumor stroma that sensitizes tumor for the therapies.

Citation Format: Tsung-Hsien Shih, Jhy-Ming Li, Guey-Yueh Shi, Hua-Lin Wu. Thrombomodulin expression regulates the tumor stroma differentiation of mesenchymal stem cells for controlling tumor growth [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 915. doi:10.1158/1538-7445.AM2017-915
Abstract 916: Asymmetric cell division regulator prevents hyperproliferation in glioma cell-of-origin
Authors: Daynac Mathieu , Petritsch Claudia K.
Published: July 2017

In the past, we demonstrated that adult oligodendrocyte progenitor cells (OPC) undergo asymmetric cell division (ACD) to self-renew and generate functional cells by unequally distributing active EGFR and the OPC-specific marker NG2. Moreover, premalignant OPC switch from an asymmetric to symmetric, self-renewing division mode at premalignant stages, and exhibit aberrant proliferation and impaired differentiation (Sugiarto S et al Cancer Cell 2011). OPC are the cell-of-origin of glioma in genetically engineered mouse models (Persson A et al Cancer Cell 2010) and OPC-like glioma cells have high tumor-initiating potential in some glioma types. These data contribute to the emerging evidence that asymmetric cell division (ACD) has tumor suppressive activity. Whether the loss of ACD directly promotes tumor initiation is unclear, because the detailed mechanisms of mammalian ACD have not been elucidated (Gomez-Lopez S et al. Cell Mol Life Sci 2014). Lethal giant larvae 1 (Lgl1) was initially identified as a tumor suppressor in Drosophila and has been implicated in the asymmetric localization of cell fate determinants in mammalian neural progenitor cells (Klezovitch et al., Genes Dev, 2004). Others have shown also that human Lgl1 is inhibited by PTEN loss, which is common in glioblastoma, and Lgl1 depletion in human glioblastoma cells increases their invasive properties (Gont et al, Oncotarget, 2013 and 2014). Whether Lgl1 restricts proliferation, promotes differentiation and prevents neoplastic transformation of OPC, by regulating their asymmetric division, is unknown. We developed a flow cytometry method to isolate proliferative and differentiation-committed OPC (COP) and showed that Lgl1 expression is elevated in differentiation. Using a Cre-conditional knock-out allele (Klezovitch et al., Genes Dev, 2004), we show that Lgl1 knockout OPC proliferate more and differentiate less when compared with Lgl1 wildtype OPC. Lgl1 depletion increases symmetric, self-renewing divisions and reduces the frequency of ACD. Lgl1 appears to control the expression of several conserved ACD regulators, as revealed by comparative Taqman expression analyses of Lgl1 knockout versus control OPC. Ongoing studies are aimed to investigate the link of Lgl1 depletion, altered ACD regulator expression and observed OPC phenotypes. Data derived from this work are expected to provide further insights into the extent to which defective ACD contributes to neoplastic transformation in all cancers.

Citation Format: Mathieu Daynac, Claudia K. Petritsch. Asymmetric cell division regulator prevents hyperproliferation in glioma cell-of-origin [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 916. doi:10.1158/1538-7445.AM2017-916
Abstract 924: Dedifferentiation into polyploid blastomere-like cancer stem cells via formation of polyploid giant cancer cells
Authors: Niu Na , Liu Jinsong
Published: July 2017

We have recently shown that polyploid giant cancer cells (PGCCs) are capable of tumor initiation and acquisition of embryonic-like stemness and thus represent a novel type of cancer stem cells. However, two important questions remain to be answered from this surprising finding: (1) how PGCCs acquire such stemness; (2) on which stage of normal development PGCCs correspond to. Here, we tracked the fate of single PGCCs induced via mitotic failure by paclitaxel. Morphologically, early spheroids derived from PGCCs were indistinguishable from human embryos at the polyploid blastomere, compaction, morula, and blastocyst-like stages by scanning electron microscopy. PGCCs showed time- and space-dependent activation of expression of the embryonic stem cell markers OCT4, NANOG, SOX2, and SSEA-1 and lacked expression of Xist. PGCCs also showed time-dependent activation of expression of the germ layer-specific markers alpha-fetoprotein, smooth muscle actin, and β3-tubulin and were capable of redifferentiation into three germ layers in vitro. PGCCs-derived daughter cells showed attenuated invasive ability and increased resistance to paclitaxel. PGCCs-derived spheroids grew into a wide spectrum of human neoplasms, including malignant dysgerminoma and embryonic carcinoma, poorly differentiated or well-differentiated carcinomas, and benign squamous tissue. We also observed PGCCs in ovarian cancer from patients treated with chemotherapy. Thus, our data demonstrated that PGCCs acquired novel cancer stem cell properties and capability to redifferentiate into different tumors including the germ cell tumors, which are at the topmost developmental hierarchy. Our studies, for the first time, link PGCCs to the polyploid blastomere-like cancer stem cells and thus offer a new paradigm for the origin of cancer.

Citation Format: Na Niu, Jinsong Liu. Dedifferentiation into polyploid blastomere-like cancer stem cells via formation of polyploid giant 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 924. doi:10.1158/1538-7445.AM2017-924
Abstract 941: CXCL1-CXCR2 signaling might recruit the bone marrow-derived mesenchymal cells to the carcinoma-associated fibroblasts of gastric cancer
Authors: Yashiro Masakazu , Okuno Tomohisa , Kasashima Hiroaki , Miki Yuichiro , Nakamae Hirohisa , Kitayama Kisyu , Kawashima Toshiyuki , Hatano Takaharu , Fujikawa Heishiro , Hasegawa Tsuyoshi , Nakane Takahiko , Hino Masayuki , Hirakawa Kosei , Ohira Masaichi
Published: July 2017

Background & Aims: Activated fibroblasts in the tumor stroma, also termed carcinoma-associated fibroblasts (CAFs), play a critical role in the progression of cancer. In our previous studies, we identified CAFs as playing an important role in cancer progression in the development of gastric cancer. However, it remains unclear which factor recruit and promote CAFs. The aim of this study is to clarify from where CAFs originate and which factor recruits them into the gastric cancer microenvironment.

Methods: In vitro study analyzed the chemotaxis-stimulating factor from gastric cancer cells using bone marrow-derived mesenchymal cells (BM-MCs). The nude mice with bone marrow transplantation from CAG-EGFP mice were used for the in vivo gastric cancer experiments. The influences of chemokine (C-X-C motif) receptor 2 (CXCR2) inhibitor on the migration of BM-MCs were examined in vitro and in vivo.

Results: BM-MCs migrated into tumor stroma of in vivo gastric cancer. The number of BM-MCs was much greater in the gastric tumor than in normal tissue from three days after inoculation of cancer cells. C-X-C motif ligand 1 (CXCL1) from gastric cancer cells significantly (p<0.001) stimulated the chemoattractant ability of BM-MCs in vitro. Anti-CXCL1 antibody and CXCR2 inhibitor significantly (p<0.05) decreased the migration-stimulating activity of gastric cancer cells. A CXCR2 inhibitor, SB225002, decreased tumor size and lymph node metastasis of gastric tumor, and significantly (p=0.039) prolonged survival of gastric-tumor bearing mice. The histologic findings indicated that SB225002 decreased the recruitment of BM-MCs into the tumor stroma, resulting in the reduction of CAFs.

Conclusions: BM-MSCs recruit into gastric tumor and differentiate into CAFs. CXCL1 from gastric cancer cells stimulates the recruitment of BM-MCs into gastric cancer locus via CXCR2 signalling. Inhibition of BM-MCs’ recruitment appears a promising therapy for gastric cancer.

Citation Format: Masakazu Yashiro, Tomohisa Okuno, Hiroaki Kasashima, Yuichiro Miki, Hirohisa Nakamae, Kisyu Kitayama, Toshiyuki Kawashima, Takaharu Hatano, Heishiro Fujikawa, Tsuyoshi Hasegawa, Takahiko Nakane, Masayuki Hino, Kosei Hirakawa, Masaichi Ohira. CXCL1-CXCR2 signaling might recruit the bone marrow-derived mesenchymal cells to the carcinoma-associated fibroblasts of gastric 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 941. doi:10.1158/1538-7445.AM2017-941
Abstract 952: Modulation of immune cell trafficking into human colorectal cancer by gut microbiota
Authors: Cremonesi Eleonora , Garzón Jesus G. , Governa Valeria , Mele Valentina , Amicarella Francesca , Padovan Elisabetta , Muraro Manuele , Zajac Paul , Oertli Daniel , Borsig Lubor , Iezzi Giandomenica
Published: July 2017

Introduction: Colorectal cancer (CRC) is a leading cause of cancer-related death. CRC infiltration by immune cells, including cytotoxic CD8+ T cells (CTLs), IFN-gamma-producing T-helper 1 cells (Th1), Foxp3+ regulatory T cells (Tregs) and CD16+ MPO+ neutrophils, is associated with favorable prognosis. However, chemokines driving these cell populations into the tumor site, their cellular sources and their microenvironmental triggers remain to be elucidated.

Aim: We investigated the chemokine/chemokine receptor network promoting CRC infiltration by immune cells associated to favorable prognosis.

Results: CRC infiltration by immune cells was associated with defined chemokine gene signatures, including CCL5, CXCL9 and CXCL10 for cytotoxic T lymphocytes and T-helper 1 cells, and CCL17, CCL22 and CXCL12 for T-helper 1 and regulatory T cells. Most of these chemokine genes were expressed by tumor cells upon exposure to gut bacteria in vitro and in vivo. Indeed, chemokine expression levels were significantly higher in orthotopic xenografts than in intraperitoneal tumors, and were drastically reduced by antibiotic treatment of tumor-bearing mice. Importantly, in human CRC samples, extents of chemokine production and immune cell infiltration was significantly associated with bacterial loads.

Conclusion: Gut microbiota stimulates chemokine production by CRC cells, thus favoring T cell recruitment into tumor tissues.

Note: This abstract was not presented at the meeting.

Citation Format: Eleonora Cremonesi, Jesus G. Garzón, Valeria Governa, Valentina Mele, Francesca Amicarella, Elisabetta Padovan, Manuele Muraro, Paul Zajac, Daniel Oertli, Lubor Borsig, Giandomenica Iezzi. Modulation of immune cell trafficking into human colorectal cancer by gut microbiota [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 952. doi:10.1158/1538-7445.AM2017-952
Abstract 956: Novel oral small molecule CXCR4 inhibitor improves activity of immune checkpoint blockade in ovarian cancer mouse model
Authors: Starbuck Kristen , McGray Robert , Masoumi-Moghaddam Samar , Francois Ariel , Odunsi Kunle , Zsiros Emese
Published: July 2017

Ovarian cancer continues to be the most lethal gynecologic malignancy with no real cure for patients presenting with advanced stage disease. Immune check point blockade showed modest clinical response in patient with recurrent ovarian cancer, thus additional therapeutic strategies for combination therapy are needed. As chemokines and their receptors drive both immune cell migration and tumor growth, angiogenesis and metastasis formation, they are an attractive target for combinatorial cancer therapy.

CXCR4 is the most highly expressed chemokine receptor in advanced stage high grade serous ovarian cancer, thus the objective of this study was to evaluate the efficacy of a novel oral small molecule CXCR4 inhibitor (X4-136) alone and in combination with immune checkpoint inhibition and the anti-angiogenic agent bevacizumab, and characterize the changes in circulating immune cells during treatment in murine ovarian cancer model. The ID8 cell line was used in C57BL/6J mice to establish an immune competent murine model and to compare single agent and combination therapy with oral X4-136 CXCR4 inhibitor, bevacizumab, and anti-PD1. During treatment blood sampling was performed and immune cells were analyzed by flow cytometry.

Our results demonstrated that single agent therapies alone with either drug had no significant effect on tumor progression or survival. Combination therapy with the CXCR4 inhibitor and anti-PD1 improved survival compared to control animals and the other combination therapy groups. The addition of bevacizumab to the dual combination did not further prolong survival. Analysis of circulating immune cells revealed elevations in CD11b+Ly6C+ and the ratio of CD11b+Ly6C+ to CD11b+Ly6G+ in groups treated with the CXCR4 inhibitor, indicating an increase in circulating myeloid cells. Bevacizumab had no activity in this mouse model as a single agent, and did not have synergistic effect in combination therapy.

For the first time we demonstrated that novel CXCR4 inhibitor X4-136 in combination therapy with anti-PD1 showed improved survival in murine ovarian cancer model. CXCR4 blockade increased the proportion of circulating myeloid cells during active treatment, thus further investigation into this novel therapeutic approach is warranted.

Citation Format: Kristen Starbuck, Robert McGray, Samar Masoumi-Moghaddam, Ariel Francois, Kunle Odunsi, Emese Zsiros. Novel oral small molecule CXCR4 inhibitor improves activity of immune checkpoint blockade in ovarian cancer mouse model [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 956. doi:10.1158/1538-7445.AM2017-956
Abstract 980: BAY-299, a novel chemical probe for in-depth analysis of the function of the bromodomain proteins BRPF2 and TAF1
Authors: Bouche Lea , Christ Clara D. , Siegel Stephan , Tallant Cynthia , Fernández-Montalván Amaury E. , Huber Kilian V. , Pütter Verra , Müller Susanne , Fedorov Oleg , Laak Antonius ter , Sugawara Tatsuo , Stöckigt Detlef , Meier Julia , Holton Simon J. , Hartung Ingo V. , Haendler Bernard
Published: July 2017

With the exception of the bromodomain and extra-terminal domain BET subgroup, little is known about the role of bromodomain (BD) containing proteins in cancer so that there is a dire need for chemical probes addressing other family members. The bromodomain and PHD-finger (BRPF) family encompasses three paralogs, BRPF1, BRPF2 and BRPF3, which are all found in histone acetyltransferase (HAT) complexes. BRPF2 is a scaffold protein and its knock-out leads to embryonic lethality at E15.5, potentially due to its role in embryonic stem cell differentiation. Here we present the structure-activity relationship (SAR) and characterization of the first selective BRPF2 chemical probe BAY-299, with additionnal strong activity at TAF1, a major component of the basal transcription initiation complex TFIID. BAY-299 shows in vitro activity for BRPF2 (IC50 = 67 nM) and TAF1 second bromodomain (BD2; IC50 = 8 nM) in the TR-FRET assay, as well as in the cellular NanoBRET assay [IC50 (BRPF2) = 575 nM; IC50 (TAF1 BD2) = 825 nM]. To the best of our knowledge BAY-299 is the only disclosed inhibitor showing BRPF2 selectivity over its two paralogues BRPF1 and BRPF3. It belongs to the 1,3-benzimidazolone scaffold and bears a novel substitution which is responsible for its high BRPF2 selectivity and also for its inactivity on BET BDs. The dual inhibitory properties of BAY-299 against BRPF2 and TAF1 make it an ideal research tool for further investigation of these two proteins in physiological and pathological processes.

Citation Format: Lea Bouche, Clara D. Christ, Stephan Siegel, Cynthia Tallant, Amaury E. Fernández-Montalván, Kilian V. Huber, Verra Pütter, Susanne Müller, Oleg Fedorov, Antonius ter Laak, Tatsuo Sugawara, Detlef Stöckigt, Julia Meier, Simon J. Holton, Ingo V. Hartung, Bernard Haendler. BAY-299, a novel chemical probe for in-depth analysis of the function of the bromodomain proteins BRPF2 and TAF1 [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 980. doi:10.1158/1538-7445.AM2017-980
Abstract 992: Patient-derived tumor organoids of neuroendocrine prostate cancer
Authors: Puca Loredana , Bareja Rohan , Shaw Reid , Karthaus Wouter , Gao Dong , Pauli Chantal , Mosquera Juan Miguel , Cyrta Joanna , Rosati Rachele , Rao Rema , Sboner Andrea , Grandori Carla , Inghirami Giorgio , Chen Yu , Rubin Mark A. , Beltran Himisha
Published: July 2017

Background: The development of neuroendocrine prostate cancer (NEPC) is one mechanism of treatment resistance to androgen receptor (AR)-targeted therapies for a subset of patients with advanced prostate cancer. This is associated with transition from a prostate adenocarcinoma to small cell/NEPC histology, low AR signaling signaling, and expression of neuroendocrine markers as Chromogranin A (CGHA), Synaphophysin (SYP) and CD56). Patient derived preclinical models recapitulating the NEPC phenotype may be used to address NEPC pathogenesis and test emerging therapeutic targets.

Methods: Tumor organoids were developed according to protocols previously described (Gao et al, Cell 2015). Briefly the tissue biopsies (liver and bone biopsy) were washed, enzymatically digested and then seeded in Matrigel (BD) droplets. Organoids were characterized at genomic (WES), RNA and protein level (IHC) to confirm the expression of specific markers. Lentiviral infections were performed using shRNAs against EZH2 to knock down EZH2 in organoids. Organoids were also subcutaneously injected in NSG mice to generate patient derived xenografts (PDXs) for drug treatment in vivo.

Results: We developed and characterized two NEPC tumor organoids from tumor biopsies (liver and bone) of two patients both in vitro and in vivo (as PDXs). NEPC tumor organoid models retained the molecular and histological characteristic of their matched patient samples. We successfully manipulated the activity of the histone methyltransferase EZH2 by using a catalytic inhibitor and its expression by infecting organoids with shEZH2. We showed that the absence of EZH2 affects the expression of neuroendocrine-associated programs as stem cell and neuronal pathway. Moreover treatment with EZH2 inhibitor decreased tumor organoids viability and PDXs tumor volume. Drug screening approaches on NEPC organoids were used to discovery novel drug targets and combinations that could potentially benefit NEPC patients. Top single agent hits included previously identified targets such as EZH2, AURKA, as well as novel synergies.

Conclusions NEPC patient tumor organoids are clinically relevant tumor models to study the NEPC phenotype in advanced prostate cancer and may be used to elucidate novel drug targets.

Citation Format: Loredana Puca, Rohan Bareja, Reid Shaw, Wouter Karthaus, Dong Gao, Chantal Pauli, Juan Miguel Mosquera, Joanna Cyrta, Rachele Rosati, Rema Rao, Andrea Sboner, Carla Grandori, Giorgio Inghirami, Yu Chen, Mark A. Rubin, Himisha Beltran. Patient-derived tumor organoids of neuroendocrine 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 992. doi:10.1158/1538-7445.AM2017-992
Abstract 998: OPeN: the oncology precision network data sharing consortium
Authors: Nadauld Lincoln , Haslem Derrick , Tittel Paul D. , Tameishi Mariko , Brown Thomas , Ford James
Published: July 2017

Background: The advent of Next-Generation Sequencing (NGS), and other molecular diagnostic technologies, has enabled the use of genomic information to guide targeted treatment in cancer patients. While this precision oncology approach can yield exciting clinical outcomes, the innumerable genomic variants identified in individual tumors effectively establishes each case as a unique N=1 clinical presentation. This scenario is contrary to a basic dogma of medical practice where historical cases and treatment outcomes guide future management and therapeutic decisions. Aggregation of large data sets, on a multi-institutional basis, has the potential to overcome the N=1 paradox and yield management insights in the implementation of precision oncology.

Methods: We have formed the Oncology Precision Network (OPeN), an oncology data sharing consortium, to aggregate big data sets consisting of clinical, genomic, pharmacological, and treatment response data from diverse patient cases. Data from Intermountain Healthcare, Stanford University, and Swedish Cancer Institute-Providence St. Joseph Health, as well as other institutions, comprises the database and is derived from 79 hospitals, over 800 physician clinics and more than 50,000 annual cases.

Results: The OPeN database can be interrogated by variant type, specific therapeutics, clinical outcomes, and by grouped variables, in a structured data format. The overarching IT platform is a cloud based, open source, triple store precision oncology solution, Syapse. These data are yielding valuable insights, including tumor mutational burden (TMB) scores and their correlation to immunotherapy response, clinical response in various drug-gene combinations, and therapy-specific adverse events.

Conclusions: We anticipate this resource will be used by the Molecular Tumor Boards of contributing institutions for clinical interpretation, and by treating providers to overcome the N=1 challenge associated with precision oncology.

Citation Format: Lincoln Nadauld, Derrick Haslem, Paul D. Tittel, Mariko Tameishi, Thomas Brown, James Ford. OPeN: the oncology precision network data sharing consortium [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 998. doi:10.1158/1538-7445.AM2017-998
Abstract CT137: Standard therapy versus active surveillance for low grade DCIS: the LORD trial
Authors: Wesseling Jelle , Duijnhoven Frederieke van , Tryfonidis Konstantinos , Peric Aleksandra , Leeuwen-Stok Elise van , Bijker Nina , Elshof Lotte , Rutgers Emiel
Published: July 2017

The introduction of population-based breast cancer screening and implementation of digital mammography have led to an increased incidence of ductal carcinoma in situ (DCIS) without a decrease in the incidence of advanced breast cancer. This suggests DCIS overdiagnosis exists.

We hypothesize that asymptomatic, low-grade DCIS can safely be managed by active surveillance. If progression to invasive breast cancer would still occur, this will be low-grade and hormone receptor positive with excellent survival rates. Also, breast-conserving treatment will still be an option, if no prior radiotherapy has been applied. It also may save many low-grade DCIS patients from intensive treatment.

We will compare active surveillance with conventional treatment, being either wide local excision (WLE) only, WLE plus radiotherapy or mastectomy, possibly followed by hormonal therapy for primary low-grade DCIS, detected by calcifications only, in a phase III, open-label, non-inferiority, multi-center, randomized clinical trial legally supported by the Breast Cancer Group of the European Organisation for the Research and Treatment of Cancer (EORTC-1401-BCG). The Dutch Centers are coordinated by the BOOG Study Center (BOOG 2014-04).

Randomization will be 1:1 in to one of the following arms: active surveillance or standard treatment per local policy. In total, 1240 women (≥ 45 years) with asymptomatic, pure, low-grade DCIS, based on vacuum-assisted biopsies of calcifications as detected by population-based or opportunistic screening, without prior breast cancer, will be included. Assuming 25% of randomized women qualified to enroll in the study will drop out or will be excluded from per protocol population, at least 1,240 women need to be randomized to obtain the 930 patients required for the evaluation of the primary endpoint. The same follow-up scheme will be applied in both study arms, i.e. annual mammography for a period of 10 years. The primary end-point is ipsilateral invasive breast tumor-free rate at 10 years. Secondary end-points are among others: overall survival, breast cancer-specific survival, mastectomy rate and patient reported outcomes. Accrual has started in January 2017.

Acknowledgements: This trial is funded by Pink Ribbon Netherlands, the Dutch Cancer Society and Dutch Cancer Society/Alpe d’HuZes.

Citation Format: Jelle Wesseling, Frederieke van Duijnhoven, Konstantinos Tryfonidis, Aleksandra Peric, Elise van Leeuwen-Stok, Nina Bijker, Lotte Elshof, Emiel Rutgers. Standard therapy versus active surveillance for low grade DCIS: the LORD trial [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 CT137. doi:10.1158/1538-7445.AM2017-CT137
Abstract DDT02-01: Discovery of GDC-0077, a highly isoform selective inhibitor of PI3Kα that promotes selective loss of mutant-p110α
Authors: Staben Steven T.
Published: July 2017

PIK3CA, the gene that encodes for the p110α catalytic subunit of phosphatidylinositol-3-kinase (PI3Kα), is frequently mutated in cancer, with activating and transforming mutations of PIK3CA occurring in approximately 17% of cancers diagnosed annually. The narrow therapeutic index of PI3K inhibitors evaluated in the clinic thus far may be due to insufficient selectivity for PI3K isoform or mutant oncogenic driver. We report the results of our efforts directed at improving efficacy and safety of a class of benzoxazepin inhibitors of PI3K. A structure-, property-, and phenotype-guided strategy directed at high PI3K-isoform and PIKK-family selectivity, as well as a distinct cellular mechanism of action, culminated in the discovery of GDC-0077. Differences in primary and tertiary structure among PI3K isoforms were leveraged to achieve >300-fold selective inhibition of the PI3Kα isoform over the β, δ, and γ isoforms in biochemical assays. Very high selectivity over PIKK-family proteins such as mTOR, DNA-PK and VPS34 was also achieved through this process. In vitro and in vivo data indicate that GDC-0077 operates by a mechanism that promotes the selective degradation of “hotspot” p110α mutants (H1047R, E545K). Treatment of nude mice bearing PIK3CA-mutant breast tumor xenografts with oral GDC-0077 resulted in tumor regressions at well-tolerated doses. Together, the high degree of isoform selectivity, selective degradation of mutant-p110α, and in vivo PK/efficacy support the clinical evaluation of GDC-0077 as a treatment for patients with locally advanced or metastatic, PIK3CA-mutant cancer.

Citation Format: Steven T. Staben. Discovery of GDC-0077, a highly isoform selective inhibitor of PI3Kα that promotes selective loss of mutant-p110α [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 DDT02-01. doi:10.1158/1538-7445.AM2017-DDT02-01
Abstract DDT02-02: SGN-2FF: A novel small molecule inhibitor of fucosylation with preclinical antitumor activity through multiple immune mechanisms
Authors: Alley Stephen C. , O'Meara Megan , Gardai Shyra J. , Okeley Nicole M.
Published: July 2017

Increased fucosylation is associated with tumor progression and metastasis, and targeting fucosylation is a novel strategy in cancer therapy. 2-Fluorofucose (SGN-2FF) has been shown to inhibit cellular fucosylation by depletion of the fucosylation substrate GDP-fucose, as well as by direct inhibition of fucosyltransferases, leading to the production of afucosylated glycoproteins including antibodies. SGN-2FF has antitumor activity in multiple mouse tumor models, showing substantial tumor growth delay. SGN-2FF also enhanced the protective effect of a lymphoma vaccine in a syngeneic mouse model (1). This protection was determined to be immune dependent since depletion of CD4 and CD8 T cells reduced the SGN-2FF/vaccine activity. In vitro, SGN-2FF has been shown to activate human T cells in an antigen-dependent manner. Therefore, by inhibiting fucosylation SGN-2FF can potentially work through multiple mechanisms, including but not limited to effects on immune cells, tumor cells, and the tumor microenvironment. A first-in-human, phase 1, multicenter dose-escalation study of SGN-2FF is ongoing to investigate the safety, pharmacokinetics, and antitumor activity of SGN-2FF given orally to patients with advanced solid tumors (NCT# 02952989). Pharmacodynamic effects, including markers of fucosylation status, will also be evaluated to help determine the optimal biologic dose. This presentation reviews the preclinical activity data of SGN-2FF and describes the design of the phase 1 study, showing how demonstrated preclinical pharmacodynamic effects on fucosylation status informed how activity and pharmacodynamics will be monitored and evaluated in the phase 1 study.

Reference

1. Okeley NM, Alley SC, Anderson ME, Boursalian TE, Burke PJ, Emmerton KM, et al. Development of orally active inhibitors of protein and cellular fucosylation. Proc Natl Acad Sci U S A 2013;110:5404-9.

Citation Format: Stephen C. Alley, Megan O'Meara, Shyra J. Gardai, Nicole M. Okeley. SGN-2FF: A novel small molecule inhibitor of fucosylation with preclinical antitumor activity through multiple immune mechanisms [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 DDT02-02. doi:10.1158/1538-7445.AM2017-DDT02-02
Abstract LB-006: Oncology model fidelity scores
Authors: Datta Debajyoti , Goldstein Theodore , Gu Zhiping , Butte Atul
Published: July 2017

Animal models remain a cornerstone of research efforts in Oncology to model the complexity of cancer progression and to discover new therapeutic approaches to disease management. With the advent of new genomic manipulation techniques such as CRISPR, and advances in mouse modeling with genetically engineered mice (GEM) and patient-derived xenografts (PDX), we can expect the development of novel and powerful animal models in the near future. These techniques are expanding our capability for pre-clinical testing of novel therapeutic agents or for n-of-1 patient-specific disease modeling. However, the reliability of animal models to faithfully recapitulate human disease, especially cancer, remains controversial, as evidenced by numerous therapeutic agents that show promise in animal models but fail in clinical trials. We propose a new scoring system called the Oncology Model Fidelity Scores, which allow researchers and clinicians to compare animal models and select those most suited for the question at hand, whether in basic science, for translational research, or within clinical applications. The formalism and tools we are developing for the analysis of mouse models and other model organisms are based on the Hallmarks of Cancer and therapeutic pathways as well as The Cancer Genome Atlas (TCGA) and other comprehensive systems. The scoring system begins with RNASEQ expression data and DNA variation analysis, and is designed for use in mapping animal models both to individual patients and to a TCGA cohort. We are applying this scoring system to mouse models available through NCI’s Oncology Model Forum and we are analyzing how these animal models compare to human cancers based on TCGA data. Ultimately, the development of an Oncology Model Fidelity Score will help to advance patient care through efficient identification and validation of animal models for a variety of applications, from pre-clinical testing of novel therapeutics to the use of patient-specific animal models.

Citation Format: Debajyoti Datta, Theodore Goldstein, Zhiping Gu, Atul Butte. Oncology model fidelity scores [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 LB-006. doi:10.1158/1538-7445.AM2017-LB-006
Abstract LB-007: Leveraging spatial heterogeneity in tumor purity for improved somatic variant calling of archival tumor-only samples
Authors: Halperin Rebecca F. , Liang Winnie S. , Tassone Erica , Adkins Jonathan , Russell Megan , Tran Nhan , Hank Nicole , Newell James , Gupta Sandeep , Berens Michael , Korn Ronald , Craig David W. , Byron Sara A.
Published: July 2017

Archival tumor samples present a rich resource of annotated specimens for genomics research. However, standard variant calling approaches require a matched normal sample from the same individual, which is often not available with archival tissue. Without a matched normal sample, it is very difficult to distinguish between true somatic variants and germline variants that are private to the individual. Archival FFPE sections often contain adjacent normal tissue, but this normal tissue is often contaminated with infiltrating tumor cells. Comparative somatic variant callers are designed to exclude variants present in the normal sample, so a novel approach is required to leverage sequencing of adjacent normal tissue. Here we present LumosVar 2.0, a software package designed to jointly analyze multiple samples from the same patient. The approach is based on the concept that the allelic fraction of somatic variants, but not germline variants, would be diluted by the presence of normal tissue. Given the allele specific copy number state and expected tumor fraction of each sample, one can model the expected allelic fractions of somatic and germline variants. LumosVar estimates allele specific copy number and tumor sample fractions from the data, and uses the model to call somatic and germline variants. LumosVar is also able to detect sub clonal events and spatial heterogeneity between samples. To evaluate this approach, we used a glioblastoma dataset, where enhancing (high tumor content) and non-enhancing (low tumor content) samples were available for each patient, as well as the matched normal sample to define the true somatic variants. We show that both sensitivity and positive predictive value are improved by analyzing the high tumor and low tumor jointly compared to analyzing the samples individually or in silico pooling of the two samples. Finally, we apply this approach to a set of breast and prostate archival FFPE tumor samples where normal samples were not available for germline sequencing.

Citation Format: Rebecca F. Halperin, Winnie S. Liang, Erica Tassone, Jonathan Adkins, Megan Russell, Nhan Tran, Nicole Hank, James Newell, Sandeep Gupta, Michael Berens, Ronald Korn, David W. Craig, Sara A. Byron. Leveraging spatial heterogeneity in tumor purity for improved somatic variant calling of archival tumor-only samples [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 LB-007. doi:10.1158/1538-7445.AM2017-LB-007
Abstract LB-017: HSP110 sustains aberrant NFkB signaling in activated B-cell diffuse large B-cell lymphoma through MyD88 stabilization
Authors: Boudesco Christophe , Causse Sebastien , Hammann Arlette , Verhoeyen Els , Martin Laurent , Fest Thierry , Wolz Oliver , Weber Alexander , Garrido Carmen , Jego Gaetan
Published: July 2017

Diffuse large B cell lymphoma (DLBCL) is an aggressive lymphoproliferative disorder of B lymphocytes accounting for 30 % of adult Non Hodgkin Lymphoma (NHL). Among DLBCL, Activated B Cell - DLBCL (ABC-DLBCL) is the most aggressive form and has a poor prognosis. Heat-shock proteins (HSPs) are molecular chaperons highly expressed in cancer cells and implicated in resistance to radio- and chemotherapy. Therefore, HSPs are envisioned as therapeutic targets in many cancers. Among the different HSPs, HSP110 has been recently identified as a pro-survival factor in germinal center-derived DLBCL (GC-DLBCL), through stabilization of the GC-DLBCL oncogene Bcl-6. Here, we have explored if HSP110 could also be involved in the survival of the most aggressive form of DLBCL. We observed a high HSP110 expression in all ABC-DLBCL patient samples, compared to normal reactive lymph nodes by using IHC staining of ABC-DLBCL tumor sections and transcriptional analysis of ABC-DLBCL patient tumors. Furthermore, shRNA silencing of HSP110 decreases the survival of several ABC-DLBCL cell lines, and downregulates the expression of pro-survival factors such as BcL2 and BcL-XL. SiRNA silencing of HSP110 abrogates NF-kB signaling, which is the major oncogenic pathway in ABC-DLBCL cell lines. In accord with these results, over-expression of HSP110 in DLBCL and non-DLBCL cell lines increases NF-kB signaling, indicating a tight interplay between HSP110 and the NF-kB pathway. Using immune-precipitation and DuolinkTM assays, we identified an in vitro and in cellulo interaction between HSP110 and Myd88, a critical protein of the NF-kB pathway that bears an activated mutation in many ABC-DLBC patients and that is responsible for lymphoma aggressiveness. Finally, we demonstrate that HSP110 stabilizes the wild type as well as the mutated form of Myd88, therefore facilitating the chronic NF-kB pathway activation in those cells. In conclusion, we identified HSP110 as a regulator of NF-kB signaling through MyD88 stabilization in ABC-DLBCL. This finding highlights HSP110 as a new potential therapeutic target in DLBCL.

Citation Format: Christophe Boudesco, Sebastien Causse, Arlette Hammann, Els Verhoeyen, Laurent Martin, Thierry Fest, Oliver Wolz, Alexander Weber, Carmen Garrido, Gaetan Jego. HSP110 sustains aberrant NFkB signaling in activated B-cell diffuse large B-cell lymphoma through MyD88 stabilization [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 LB-017. doi:10.1158/1538-7445.AM2017-LB-017
Abstract LB-019: Hakai, an E3-ligase for E-cadherin, stabilizes δ-catenin through Src kinase
Authors: Shrestha Hridaya , Ryu Taeyong , Seo Young-woo , Park So-yeon , He Yongfeng , Dai Weiye , Park Eunsook , Simkhada Shishli , Kim Hangun , Lee Keesook , Kim Kwonseop
Published: July 2017

Hakai ubiquitinates and induces endocytosis of the E-cadherin complex; thus, modulating cell adhesion and regulating the epithelial-mesenchymal transition in development of metastasis. Our previous published data show that δ-catenin promotes E-cadherin processing and thereby activates β-catenin-mediated oncogenic signals in prostate cancer. Although several published data show the interactions between δ-catenin and E-cadherin; and Hakai and E-cadherin separately, we found no published report on the relationship between δ-catenin and Hakai. In this study, we show Hakai stabilizes δ-catenin regardless of its E3-ligase activity. We found that Hakai and Src increase the stability of δ-catenin synergistically. Furthermore, we show that Hakai stabilizes Src, which in turn inhibits binding between glycogen synthase kinase-3β and δ-catenin, resulting in less glycogen synthase kinase-3β mediated phosphorylation and proteosomal degradation of δ-catenin. Taken together, these results suggest that stabilization of δ-catenin by Hakai is dependent on Src. Our novel findings on the Hakai mediated δ-catenin stabilization in an ubiquitination independent manner will add a new perspective to provide further insight into E3-ligase activity independent role of Hakai in cancer pathogenesis.

Citation Format: Hridaya Shrestha, Taeyong Ryu, Young-woo Seo, So-yeon Park, Yongfeng He, Weiye Dai, Eunsook Park, Shishli Simkhada, Hangun Kim, Keesook Lee, Kwonseop Kim. Hakai, an E3-ligase for E-cadherin, stabilizes δ-catenin through Src kinase [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 LB-019. doi:10.1158/1538-7445.AM2017-LB-019
Abstract LB-028: Mdm4 regulates mutant p53 stability in vivo
Authors: Plehaty Molly , Srinivas Tara , Stevens Wanida , Sobhani Nema , Iwakuma Tomoo , Podell Brendan , Arbab Farinaz , Terzian Tamara
Published: July 2017

The p53 tumor suppressor is maintained mainly at low physiological levels in normal cells by its two major inhibitors, Mdm2 and Mdm4. Mdm2 is an E3 ubiquitin ligase while Mdm4 lacks this activity. Deletion of either inhibitor results in p53-dependent embryonic lethality in mice. We have shown that Mdm2 binds and inhibits mutant p53R172H in a mouse model of Li-Fraumeni syndrome. We recently established that Mdm4, like Mdm2, regulates p53R172H stability in vivo, and that endogenous Mdm2 cannot compensate for this stabilization. Thus, mice that lack Mdm4 and are homozygous for the p53R172H allele have stabilized p53R172H and display accelerated tumor development and an increased range of tumor types, compared to p53R172H/R172H mice. Furthermore, we compared mutant mice with the loss of two different alleles of Mdm4 and observed a threshold for metastasis associated with higher p53R172H levels. These data support the gain-of-function hypothesis: high levels of mutant p53 increase the frequency of metastasis. We are currently analyzing mutant p53 target genes expression differences between the two Mdm4 alleles and Mdm2 to assess mutant p53 mode of regulation of these alleles.

Citation Format: Molly Plehaty, Tara Srinivas, Wanida Stevens, Nema Sobhani, Tomoo Iwakuma, Brendan Podell, Farinaz Arbab, Tamara Terzian. Mdm4 regulates mutant p53 stability in vivo [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 LB-028. doi:10.1158/1538-7445.AM2017-LB-028