bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract SY20-02: Inhibitor combinations targeting KRAS effector signaling in KRAS-mutant pancreatic cancer
Authors: Cox Adrienne D. , Goodwin Craig M. , Bryant Kirsten L. , Dagliyan Irem , George Samuel D. , Lucas Kelly E. , Gautam Prson , Wennerberg Krister , Der Channing J.
Published: August 2018

KRAS mutations are found in 95% of pancreatic ductal adenocarcinoma (PDAC), where they are key cancer drivers. Effective anti-KRAS therapeutics are thus anticipated to make a significant improvement in PDAC treatment. Despite the promise of inhibiting KRAS effector signaling, such inhibitors have not demonstrated significant activity as monotherapy, and there are concerns regarding potential normal tissue toxicity. Inhibitor combinations may overcome limitations of both efficacy and toxicity. We performed a 525-drug chemical biology screen to identify combinations that enhanced the cytotoxic activity of inhibitors of the RAF-MEK-ERK and the PI3K-AKT-mTOR effector pathways. Many such combinations were identified for RAF effector pathway inhibitors, while few were identified for PI3K pathway inhibitors. Generally, the same classes of inhibitors were identified for inhibitors of the RAF, MEK, and ERK nodes of the MAP kinase (MAPK) cascade. We found that inhibitors of the PI3K-AKT-mTOR pathway, microtubules, HDAC, and HSP90 each synergistically enhanced the cytotoxicity of RAF, MEK, and ERK inhibitors, in both conventional and PDX-derived PDAC cell lines. Mechanistically, we found that a shared basis for this synergy was enhanced loss of MYC protein, a key ERK substrate. Our studies identify promising combinations of KRAS effector inhibitors for PDAC treatment.

Citation Format: Adrienne D. Cox, Craig M. Goodwin, Kirsten L. Bryant, Irem Dagliyan, Samuel D. George, Kelly E. Lucas, Prson Gautam, Krister Wennerberg, Channing J. Der. Inhibitor combinations targeting KRAS effector signaling in KRAS-mutant pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr SY20-02.
Abstract A05: Deep immunofluorescence imaging of solvent-cleared mouse mammary glands
Authors: Polec Anna , Norum Jens Henrik , Brech Andreas , Sorlie Therese
Published: August 2018

We seek to trace the progression of epithelial lesions originating from Lgr5+ cells in mouse mammary glands using the 3DISCO protocol for solvent-cleared tissue. Lineage tracing is increasingly being used to probe different cell types that exist within the mammary gland. Lgr5 is a stem cell marker and it is expressed in several different tissues including colon, stomach, and breast. It has been reported that Lgr5+ cells are necessary for mammary gland organogenesis. However, the cells that initiate tumor formation have remained intangible. Lgr5+ cells reside within the basal cell population of mammary ducts. Lgr5 is a downstream target of Wnt and therefore Lgr5+ cells may have a role in breast cancer progression. Since heterogeneity of tumors is shaped by several factors, including the cell of origin, specific oncogenic events, and interactions between tumor cells and cells of the microenvironment, it is important to obtain 3-dimensional information of tumor development.

We used the 3DISCO protocol for solvent-clearing mammary fat pads for deep immunofluorescence staining of transgenic mice harboring a EGFP reporter for Lgr5+ cells (mouse: Lgr5-EGFP-Ires-CreERT2). We performed deep immunofluorescence staining with DAPI and an antibody against the basal cell marker keratin 5 (K5).

Mammary fat pads were successfully solvent-cleared and prepared for deep immunofluorescence staining. Epithelial mammary ducts were easily recognized within the fat tissue using DAPI nuclear staining and an antibody against K5. Three-dimensional confocal microscope imaging protocols for whole mammary glands, including epithelial ducts, were established. We optimized the method using tile scans covering the entire fat pad, and multiple z-stacks of selected areas of Lgr5+ cells expressing EGFP were also detected and colocalized with K5+ cells.

The whole-organ tissue clearing, assessed in the mouse mammary gland, is suitable to obtain 3-dimensional information of various cell populations using specific molecular markers. This technique enables high-resolution, 3D imaging and phenotyping of tissue and might significantly enhance our understanding of mammary gland tumorigenesis. We will use the established protocol to localize the appearance of early lesions in mouse mammary glands and determine the role of Lgr5+ cells in mammary tumor development.

Citation Format: Anna Polec, Jens Henrik Norum, Andreas Brech, Therese Sorlie. Deep immunofluorescence imaging of solvent-cleared mouse mammary glands [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr A05.
Abstract A36: Chemosensitivity to trastuzumab emtansine (T-DM1) differs in naturally or transduced HER2-overexpressing human breast cancer cells
Authors: Wu Jeffrey , Muldoon Leslie , Neuwelt Edward
Published: August 2018

Human epidermal growth factor receptor-2 (HER2) is overexpressed in 25-30% of breast cancers and is associated with distant metastasis and poor survival. Trastuzumab emtansine (T-DM1), an antibody-drug conjugate of anti-HER2 mAb trastuzumab linked to microtubule-targeting agent mertansine, has been approved for the treatment of HER2-positive metastatic breast cancer. Chemoresistance has been a major obstacle to T-DM1 treatment, and mechanisms remain incompletely understood. We tested T-DM1 chemosensitivity in vitro and in vivo using two human breast cancer cell lines, MDA-MB-231BR-HER2 (triple-negative cells stably transfected with HER2 plasmid) and HCC1954 (natural HER2 overexpression), which show equivalent HER2 and αv integrin protein levels. MDA-MB-231BR-HER2 was strongly resistant to T-DM1, with doses as high as 1 µg/ml failing to induce apoptosis indicated by the presence of cleaved PAPR protein. In contrast, HCC1954 cells are sensitive to T-DM1, with doses as low as 10 ng/mL causing cytotoxicity in a dose-dependent manner. Cellular internalization of trastuzumab-pHrodo conjugates was significantly higher in HCC1954 than MDA-MB-231BR-HER2, but no difference was found in anti-EGFR-Ab-pHrodo conjugates internalization. Endocytosis-related proteins caveolin-1 and rab5, but not early endosome antigen, were diminished in HCC1954 cells. Consistently, single-dose treatment with T-DM1 (3.6 mg/kg, IV) significantly reduced brain tumor volume in rats inoculated with HCC1954 but not MDA-MB-231BR-HER2 cells in an intracerebral xenograft breast cancer brain metastasis model. In conclusion, our findings suggest that rab5 and caveolin-1 proteins mediating antibody internalization and/or natural vs transduced HER2 overexpression may provide possible mechanisms in resistance of T-DM1 and should be investigated when HER2-positive cancer patients fail T-DM1 HER2-targeted therapy in clinical settings.

Citation Format: Jeffrey Wu, Leslie Muldoon, Edward Neuwelt. Chemosensitivity to trastuzumab emtansine (T-DM1) differs in naturally or transduced HER2-overexpressing human breast cancer cells [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr A36.
Abstract A47: Long-term treatment of bortezomib reduced resistance to doxorubicin by reducing CerS6/GCS and elevating CerS2/GBA expressions
Authors: Shin Kim , Dongeun Kim , Inkeun Park , Woo-Jae Park
Published: August 2018

Multiple drug resistance (MDR) is main cause of chemotherapy failure in breast cancer. Herein, we tried to find the mechanism of MDR. Since overexpression of glucosylceramide synthase (GCS) plays an important role in development of MDR, we analyzed expression levels of many molecules from TCGA data to find a connection between GCS and other molecules. Interestingly, correlations between GCS and ceramide synthase 6 (CerS6), and between glucocerebosidase (GBA) and CerS2, 4, 5 were analyzed. To further analyze whether these correlations are true, we treated C16~C24-ceramide to MD-MBA-361 cells. C24-ceramide treatment for 48 and 72 hrs increased GBA expression, which increased susceptibility of apoptosis upon doxorubicin treatment. Moreover, C16-ceramide treatment for 16 weeks increased GCS expression, which also induced MDR1 protein expression. Recently we found that bortezomib, an FDA-approved proteasome inhibitor, increased CerS2 and decreased CerS6 expressions in a dose-dependent manner. To further understand whether bortezomib affects MDR, bortezomib was treated with doxorubicin for 6-8 months and it prevented doxorubicin-induced MDR development by reducing CerS6 and elevating CerS2. In conclusion, downregulation of CerS6 and upregulation of CerS2 is a good strategy to prevent development of MDR, and bortezomib can be used for the prevention of acquired MDR.

Citation Format: Kim Shin, Kim Dongeun, Park Inkeun, Park Woo-Jae. Long-term treatment of bortezomib reduced resistance to doxorubicin by reducing CerS6/GCS and elevating CerS2/GBA expressions [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr A47.
Abstract A64: Cold-inducible RNA binding protein (CIRP) links inflammation and breast cancer
Authors: Lujan Daniel Albino , Perrone-Bizzozero Nora , Beswick Ellen J. , Kusewitt Donna F. , Hartley Rebecca S.
Published: August 2018

RNA binding proteins (RBPs) post-transcriptionally regulate gene expression by associating with the regulatory sequences in the untranslated regions of mRNAs. RBPs are often disrupted in cancer, but current knowledge of their role in regulating cancer-associated genes is largely based on in vitro studies. This study seeks to determine the in vivo role of cold-inducible RBP (CIRP), which is overexpressed in some human breast cancers. CIRP promotes cell proliferation and survival and inhibits apoptosis in vitro, as well as promotes inflammation in vivo, all hallmarks of cancer. We set out to test the hypothesis that CIRP promotes breast tumorigenesis in vivo by crossing a transgenic mouse overexpressing CIRP in the mammary epithelium with the PyMT mouse model of breast cancer. Effects on both early (7 weeks of age) and late (14 weeks) tumorigenesis were assessed. Unexpectedly, mammary glands from 7-week CIRP/PyMT mice had 50% fewer mammary intraepithelial neoplasias than those from PyMT mice. Consistent with this, histopathologic analysis showed decreased mitosis and increased apoptosis in CIRP/PyMT vs. PyMT mammary glands. Late-stage tumorigenesis was also inhibited. CIRP/PyMT mice had slower tumor growth kinetics, smaller tumors, decreased tumor burden, and decreased pulmonary metastasis compared to PyMT mice. To assess mechanism, mammary glands from 7- and 14-week mice were incubated in medium overnight followed by Luminex cytokine assays on the medium. Results showed a decrease in cytokines that promote inflammation, angiogenesis, and metastasis. Altogether, results suggest that in vivo, CIRP inhibits proliferation and promotes apoptosis to suppress early tumorigenesis, potentially via decreasing the protumorigenic inflammatory response.

Citation Format: Daniel Albino Lujan, Nora Perrone-Bizzozero, Ellen J. Beswick, Donna F. Kusewitt, Rebecca S. Hartley. Cold-inducible RNA binding protein (CIRP) links inflammation and breast cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr A64.
Abstract B14: Sprouty4 regulates the transition to invasive breast ductal carcinoma through ERK/MAPK signaling
Authors: Brock Ethan J. , Jackson Ryan , Boerner Julie L. , Li Quanwen , Sloane Bonnie F. , Mattingly Raymond R.
Published: August 2018

Breast cancer is one of the most common oncologic developments in U.S. women, with approximately 25% of these cases being in situ disease (DCIS). For many years DCIS lesions have been treated using surgery and radiotherapy with the goal of decreasing the amount of late-stage disease. Unfortunately, a number of reports have since shown that early intervention is not sufficient and have highlighted the likelihood of overtreatment. This is especially true for triple-negative breast cancers, which are more strongly associated with distant recurrence, metastasis, and death compared to other types of invasive breast ductal carcinoma (IDC). These factors have generated a substantial clinical need for reliable biomarkers or molecular determinants to assess disease progression. Sprouty proteins are recognized as important regulators of ERK/MAPK signaling, and have been studied in various cancers. We hypothesize that Sprouty4 is an endogenous inhibitor of ERK/MAPK signaling, and its loss or reduced expression is a mechanism by which DCIS lesions progress toward IDC, including triple-negative disease. Using immunohistochemistry we found that Sprouty4 expression was reduced in IDC patient tissue samples compared to normal or DCIS tissues, and that ERK/MAPK activity had an inverse relationship to Sprouty4 expression. These results correspond with immunoblot data from our 3D culture model of breast cancer progression in which Sprouty4 expression was higher during DCIS than in the IDC stage. Efficient overexpression of Sprouty4 reduced both ERK/MAPK activity as well as the aggressive phenotype of MCF10.CA1d IDC cells. Immunofluorescence experiments revealed data consistent with the relocation of E-cadherin back to the cell surface and the restoration of adherens junctions. To determine whether these effects were due to changes in ERK/MAPK signaling, IDC cells were treated with MEK162, an allosteric MEK inhibitor. Nanomolar concentrations of drug produced the restoration of an epithelial-like phenotype similar to Sprouty4 overexpression. From these data we conclude that Sprouty4 may act to control ERK/MAPK signaling in DCIS, thus limiting the progression of these premalignant breast lesions.

Citation Format: Ethan J. Brock, Ryan Jackson, Julie L. Boerner, Quanwen Li, Bonnie F. Sloane, Raymond R. Mattingly. Sprouty4 regulates the transition to invasive breast ductal carcinoma through ERK/MAPK signaling [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr B14.
Abstract B20: Glutamine metabolic vulnerabilities define triple-negative from luminal A breast cancer subsets
Authors: Geldermalsen Michelle van , Quek Lake-Ee , Turner Nigel , Balaban Seher , Hoy Andrew , Wang Qian , Holst Jeff
Published: August 2018

Although a nonessential amino acid in normal cells, the demand for glutamine is dramatically increased throughout malignant transformation to support increased metabolic demands; namely, provision of catabolic substrates for ATP production and anabolic substrates for the citric acid cycle and subsequent macromolecule biosynthesis, as well as potentiating the uptake of other critical amino acids by acting as an obligate exchange substrate. Elevated expression of glutamine metabolism-related genes, MYC-driven transcriptional events, and increased consumption and reliance on glutamine are all associated with aggressive breast cancers, including the high-risk triple-negative (TN) subtype. We recently showed that in breast cancer cells, glutamine uptake by the small neutral amino acid transporter, ASCT2, is required to sustain TN cell growth in vitro and in vivo. We therefore hypothesized that highly proliferative TN breast cancers that are sensitive to ASCT2 inhibition may have unique metabolic signatures that could be additionally exploited for therapeutic purposes.

Using a targeted metabolomics approach, we combined labeled substrate tracing, liquid chromatography coupled tandem-mass spectrometry (LC-MS/MS), and gas chromatography mass spectrometry (GC-MS) to analyze intracellular levels of key tricarboxylic acid (TCA) cycle intermediates, glycolytic metabolites, fatty acid precursors, and amino acids in human breast cancer cell lines. These analyses revealed distinct metabolic effects when glutamine uptake was blocked in vitro by L-γ-glutamyl-p-nitroanilide (GPNA), a pharmacologic inhibitor of ASCT2. These data confirm a broad reliance on glutamine availability in TN breast cancers, reinforced by TCGA gene expression data showing a specific upregulation of multiple glutamine metabolism enzymes that is completely absent in the luminal A subtype. These data emphasize the link between increased glutamine metabolism and clinically aggressive breast cancers, thus highlighting the therapeutic potential of targeting glutamine metabolism pathways in these patients.

Citation Format: Michelle van Geldermalsen, Lake-Ee Quek, Nigel Turner, Seher Balaban, Andrew Hoy, Qian Wang, Jeff Holst. Glutamine metabolic vulnerabilities define triple-negative from luminal A breast cancer subsets [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr B20.
Abstract B21: Improved efficacy of mitochondrial disrupting agents upon inhibition of autophagy in a mouse model of BRCA1-deficient breast cancer
Authors: Yeo Syn Kok , Paul Ritama , Haas Michael , Wang Chenran , Guan Jun-Lin
Published: August 2018

Breast cancer is a heterogeneous disease, and stratification of patients is fundamental to the success of treatment modalities. Breast tumors deficient in BRCA1 are mostly associated with basal-like breast cancers, and targeted therapeutics for this disease subtype are still lacking. In order to address whether autophagy inhibition will be effective in BRCA1-deficient mammary tumors, we generated mice with conditional deletion of an essential autophagy gene FIP200 along with Brca1 and Trp53, through utilization of the K14-Cre transgene. We found that FIP200 deletion suppressed tumorigenesis in the BRCA1-deficient model when compared to wild-type and heterozygous FIP200 controls. However, in contrast to previous studies in the MMTV-PyMT model, tumor growth and the distribution of histologic subtypes were not affected by loss of FIP200. Interestingly, loss of FIP200 decreased mitochondrial mass and oxidative respiratory capacity of these tumor cells, along with a decrease in the phosphorylation of mTOR substrates and transcript levels of genes involved in mitochondrial biogenesis. Importantly, we observed an increased sensitivity to mitochondrial disrupting agents upon loss of FIP200. Consequently, our data showed that combination of an autophagy inhibitor, Spautin-1, along with a mitochondrial complex I inhibitor, metformin, was more effective in limiting oxidative respiratory capacity, colony-forming ability, and tumor growth. Altogether, our results indicate that inhibition of autophagy can increase the benefits of metformin treatment in BRCA1-deficient breast cancers.

Citation Format: Syn Kok Yeo, Ritama Paul, Michael Haas, Chenran Wang, Jun-Lin Guan. Improved efficacy of mitochondrial disrupting agents upon inhibition of autophagy in a mouse model of BRCA1-deficient breast cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr B21.
Abstract B46: Targeting EZH2 reactivates a breast cancer subtype-specific antimetastatic transcriptional program
Authors: Hirukawa Alison , Smith Harvey , Zou Dongmei , Savage Paul , Johnson Radia , Bourque Guillaume , Giguere Vincent , Basik Mark , Dufour Cathy , Park Morag , Muller William
Published: August 2018

Emerging evidence has illustrated the importance of epigenomic reprogramming in cancer, with altered post-translational modifications of histones contributing to the pathogenesis of many tumor types, including breast cancer. However, the contributions of histone modifiers to breast cancer progression are unclear, and how these processes vary between molecular subtypes has yet to be adequately addressed. In this study, we demonstrate that genetic or pharmacologic targeting of the epigenetic modifier Ezh2 dramatically hinders metastatic behavior in a mouse model of breast cancer reflective of the luminal B subtype. We also employ patient-derived xenografts from different intrinsic subtypes of breast cancer to confirm that pharmacologic inhibition of Ezh2 activity hinders metastasis specifically in the luminal B subtype. We further define a molecular mechanism intrinsic to the luminal B subtype whereby EZH2 maintains H3K27me3-mediated repression of the FOXC1 gene, thereby inactivating a FOXC1-driven, antiinvasive transcriptional program. We demonstrate that higher FOXC1 levels are predictive of favorable outcome specifically in luminal B breast cancer patients and establish the use of EZH2 methyltransferase inhibitors as a viable strategy to block metastasis in luminal B breast cancer, where options for targeted therapy are currently limited.

Citation Format: Alison Hirukawa, Harvey Smith, Dongmei Zou, Paul Savage, Radia Johnson, Guillaume Bourque, Vincent Giguere, Mark Basik, Cathy Dufour, Morag Park, William Muller. Targeting EZH2 reactivates a breast cancer subtype-specific antimetastatic transcriptional program [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr B46.
Abstract B47: Validation of novel breast cancer drivers using mammary stem cell-based somatic mouse models
Authors: Zhang Zheng , Christin John R. , Wang Chunhui , Ge Kai , Oktay Maja , Guo Wenjun
Published: August 2018

Cancer genomics has provided an unprecedented opportunity for understanding genetic causes of human cancer. However, distinguishing which mutations are functionally relevant to cancer pathogenesis remains a major challenge. We describe here a mammary stem cell (MaSC) organoid-based approach for rapid generation of somatic genetically engineered mouse models (GEMMs). By using RNAi and CRISPR-mediated genome engineering in MaSC-GEMMs, we have discovered that inactivation of Ptpn22 or Mll3, two genes mutated in human breast cancer, greatly accelerated PI3K-driven mammary tumorigenesis. Using these tumor models, we have also identified genetic alterations promoting tumor metastasis and causing resistance to PI3K- targeted therapy. Both Ptpn22 and Mll3 inactivation resulted in disruption of mammary gland differentiation and an increase in stem cell activity. Mechanistically, Mll3 deletion enhanced stem cell activity through activation of the HIF pathway. Thus, our study has established a robust in vivo platform for functional cancer genomics and has discovered functional breast cancer mutations.

Citation Format: Zheng Zhang, John R. Christin, Chunhui Wang, Kai Ge, Maja Oktay, Wenjun Guo. Validation of novel breast cancer drivers using mammary stem cell-based somatic mouse models [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr B47.
Abstract B51: Genetic etiology of ER low/HER2- breast tumors
Authors: Lovejoy Leann A. , Shriver Craig D. , Ellsworth Rachel E.
Published: August 2018

Background: In 2010, the American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP) issued guidelines that tumors with >1% positively staining cells should be considered ER positive. Numerous studies have demonstrated that tumors with 1-9% ER-positive cells (low staining) represent ER-negative intrinsic subtypes with outcomes similar to ER-negative tumors. Given the similarities between low-staining tumors and TNBC, we investigated whether low-staining tumors share a germline etiology with TNBC.

Methods: The Clinical Breast Care Project was queried to identify all tumors with percent ER-positive cells and HER2 data available. Genomic DNA was isolated from available blood samples from patients with HER2-negative tumors with either negative (TNBC) or low-staining (1-9%) ER status. Targeted sequencing was performed using the Illumina TruSight Cancer panel. Pathogenic mutations were identified using VariantStudio and classified as pathogenic, likely pathogenic, uncertain significance (VUS), likely benign, or benign using ClinVar.

Results: Low ER/HER2- tumors and TNBC represented 50 (2.7%) and 223 (12.2%) of the 1819 tumors in the database. Patients with low-staining tumors and TNBC did not differ significantly by age at diagnosis, ethnicity, family history, tumor stage, size, grade, or survival, and all the low ER/HER2- tumors with gene expression data available (n=17) were basal-like. Four (9%) of the women with low ER/HER2- tumors had pathogenic mutations in BRCA1 or BRCA2; an additional 4 (9%) had pathogenic mutations in the cancer predisposition genes BLM (n=2), FH (n=1), and MUTYH (n=1). Seven others had VUS in BRCA2, BRIP1, CHEK2, MSH2, MSH6, and SMAD4. Frequency of pathogenic mutations did not differ significantly (P=0.139) between low-staining tumors (18%) and TNBC (13%).

Discussion: Low ER/HER2- tumors share similar clinicopathologic characteristics and outcomes with TNBC and have a significant genetic component, with 9% of patients having BRCA1 or BRCA2 germline mutations and an additional 9% having mutations in other cancer-predisposing genes. These data suggest that while ASCO/CAP guidelines define low ER tumors as ER positive, women with low ER/HER2- tumors may benefit from the clinical care and genetic testing provided to women with TNBC.

The views expressed in this article are those of the author and do not reflect the official policy of the Department of Army/Navy/Air Force, the Department of Defense, or the U.S. Government.

Citation Format: Leann A. Lovejoy, Craig D. Shriver, Rachel E. Ellsworth. Genetic etiology of ER low/HER2- breast tumors [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr B51.
Abstract B64: Sox10 drives tumor progression in breast cancer by reprogramming mammary tumor cells into a state of plasticity resembling primitive neural crest cells
Authors: Dravis Christopher , Wahl Geoffrey
Published: August 2018

Many foundational features of tumor malignancy such as tumor initiation, tumor heterogeneity, therapeutic resistance, and metastasis are driven through dysregulated cell plasticity. Thus, the development of strategies to counter mechanisms of reprogramming in cancer cells is a critical area of need in the field. To address this challenge, we have focused on discovering how cell plasticity is specified in normal mammary development and tissue, and how these processes may be co-opted to drive tumor progression in breast cancer. To facilitate the study of these complex phenomena, we have developed a CRISPR- and tissue engineering-based platform system to rapidly generate de novo, in vivo, mammary glands and mammary tumors that carry any conceivable genomic modification. Here, we have used this system to study the function of Sox10 in breast cancer, as we have previously shown that the transcription factor Sox10 is a critical mammary cell plasticity factor that labels and is functionally required for stem/progenitor activity in normal mammary cells. We now demonstrate that Sox10 is also a major plasticity factor in breast cancer. We find that Sox10 is expressed in both human breast cancer and multiple murine mammary tumor models, and demonstrate critical roles for Sox10 in driving both tumor initiation and progression. Sox10 expression in these tumors correlates with multiple indicators of elevated cell plasticity, which include features of de-differentiation and EMT, specific enrichment of mammary stem/progenitor identity, and expanded lineage potential compared to normal mammary cells. In addition to its role in specifying stem/progenitor activity in mammary cells, Sox10 is also a dominant specifier of neural crest cells, a primitive and highly plastic cell state found only in the early embryo. Strikingly, we find that Sox10+ mammary tumor cells also exhibit transcriptional and epigenetic features of neural crest cells that are not found in normal mammary cells. Collectively, these data reveal that Sox10 is a major plasticity factor that contributes to mammary tumor progression, and demonstrate the remarkable scope of cell state reprogramming that can occur during tumorigenesis when potent plasticity factors are dysregulated.

Note: This abstract was not presented at the conference.

Citation Format: Christopher Dravis, Geoffrey Wahl. Sox10 drives tumor progression in breast cancer by reprogramming mammary tumor cells into a state of plasticity resembling primitive neural crest cells [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr B64.
Abstract IA12: Precision medicine for triple-negative breast cancer patients using a systems biology approach
Authors: Perou Charles M.
Published: August 2018

Triple-negative breast cancers (TNBC = ER-, PR-, and HER2-negative) are among the most clinically challenging because of their poor prognosis and paucity of approved treatment options. TNBC is composed of multiple disease subtype, with multiple classification systems having been developed. These methods are largely in agreement and identify four basic groups including basal-like, Claudin-low/mesenchymal, immune-infiltrated, and luminal-type (LAR). Each of these distinct patient subsets may require distinct therapeutic strategies, some of which will be discussed.

Within TNBC, the basal-like disease type predominates (70-80%), but again, all the intrinsic subtypes are also present. Interestingly, luminal/TNBC or HER2-enriched/TNBC show very similar gene expression patterns to luminal/ER+ or HER2-enriched/HER2+, except for expression of ERBB2 (and the genes in the 17q amplicon). Importantly, the distinction between basal-like versus non-basal-like within TNBC seems to be important for predicting 1) survival following (neo)adjuvant multiagent chemotherapy, 2) bevacizumab benefit in the neoadjuvant setting (CALGB40603), and 3) docetaxel vs. carboplatin benefit in the first-line metastatic setting (TNT Trial). In addition, genomic predictors of chemotherapy benefit for TNBC typically identify tumor and immune cell features as positive predictors of response, thus highlighting the importance of the microenvironment in response and survival, and highlighting the importance of methods that can account for both of these key features.

TNBC are also more common in younger women and African American women, which contributes to racial disparities in mortality due to breast cancer. Recent TCGA analyses suggest that there are few molecular differences in the somatic tumor landscape according to race, which suggests that access to health care and/or adherence to therapy may be the major contributors to differences in outcomes according to race. Overall, these data suggest that intrinsic molecular profiling, plus measures of the microenvironment, can provide clinically relevant information beyond current pathology-based classifications, which can assist in making more precise therapy recommendations for TNBC patients.

Citation Format: Charles M. Perou. Precision medicine for triple-negative breast cancer patients using a systems biology approach [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr IA12.
Abstract IA22: Integrating immunotherapy and targeted therapy in breast cancer
Authors: Zhao Jean
Published: August 2018

Therapeutic resistance is a major obstacle in the clinic for cancer treatment. Utilizing our novel genetically engineered mouse models (GEMMs) of cancer driven by inducible expression of oncogenic PIK3CA or HER2, coupled with pharmacologic approaches, we identified several significant resistance mechanisms to PI3K- or HER2-targeted therapy. For example, we found spontaneous focal amplification of Met and Myc, recurrent mutations in Ras and β-catenin, and compensatory activation of the MAPK pathway render resistance to PI3K inhibition. We recently identified Cyclin D1-CDK4 mediated resistance to HER2-targeted therapy through a signaling feedback loop. Beyond suppressing cell cycle progression, we found that CDK4/6 inhibitors promote antitumor immunity and increase cytotoxic T cell-mediated clearance of tumor cells, which is further enhanced by the addition of immune checkpoint blockade. More importantly, these results led to the design of clinical trials with CDK4/6 inhibitor in combination with HER2-targeted therapy and PD1 blockade for patients with metastatic, refractory HER2+ breast cancer. Parallel to GEMMs, we have led the efforts to establish and characterize novel cancer patient-derived xenograft (PDX) models, with an emphasis on brain metastases, an emerging clinical challenge. I will discuss how we have used these models to discover therapeutic strategies that integrate targeted therapy and immunotherapy to overcome resistance and to drive these discoveries to the clinical trials.

Citation Format: Jean Zhao. Integrating immunotherapy and targeted therapy in breast cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr IA22.
Abstract A61: Ascites-derived and tissue-derived ovarian cancer cell primary 3D cultures aimed for personalized medicine
Authors: Nanki Yoshiko , Hirasawa Akira , Nomura Hiroyuki , Okubo Aki , Itoh Manabu , Akahane Tomoko , Chiyoda Tatsuyuki , Kataoka Fumio , Tominaga Eiichiro , Aoki Daisuke
Published: August 2018

Objective: Ovarian cancer is a poor-prognosis gynecologic disease with over 220,000 diagnoses each year worldwide and a 5-year survival rate less than 40%. In this study, we present a method for isolation and characterization of ovarian cancer cells from patient-derived ascites and tissue samples by using three-dimensional (3D) cell culture.

Materials and Methods: Ascites and tissue samples were obtained from primary ovarian, peritoneal, and fallopian tube cancer patients intraoperatively. Samples were isolated and cultured within 6 hours after collection. After isolation, cells were resuspended in Matrigel and were placed at the center of each well. Optimized medium is added to each well. NanoCulture Plate LH96 (Low-Binding, MH pattern, 96-wells, Medical and Biological Laboratories Co., Ltd., Japan) were used for 3D cell culture. Plates were incubated at 37°C. The cultures were examined for metabolically active cells by ATP assay and medium changed on days 0, 1, 4, 7, 10, and 14.

Results: We successfully obtained ascites-derived primary cell cultures within 1-7 days from 100% (3/31) of the ascites samples and 62% (5/8) from tissue-derived primary cell cultures. Spheroids-like structures were formed in 30% (1/3) of ascites samples and 50% (4/8) of tissue samples. The tumorigenicity and invasiveness of the cells were demonstrated using new 3D spheroid model cultured in vitro by NanoCulture Plate LH96.

Conclusion: Primary ascites and tissue culture of ovarian cancer cells can successfully be cultured by 3D cell culture plates. We may apply this method for drug sensitivity testing; therefore, 3D cell culture has a potential to evaluate the sensitivity of candidate chemotherapeutic drug for individual patients.

Citation Format: Yoshiko Nanki, Akira Hirasawa, Hiroyuki Nomura, Aki Okubo, Manabu Itoh, Tomoko Akahane, Tatsuyuki Chiyoda, Fumio Kataoka, Eiichiro Tominaga, Daisuke Aoki. Ascites-derived and tissue-derived ovarian cancer cell primary 3D cultures aimed for personalized medicine. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr A61.
Abstract IA12: Acquired chemotherapy resistance in high-grade serous ovarian cancer patients
Authors: Christie Elizabeth L. , Beach Jessica , Etemadmoghadam Dariush , Garsed Dale , Patch Ann-Marie , Fereday Sian , Pattnaik Swetansu ,   Australian Ovarian Cancer Study, Brady Samuel , Bild Andrea , Bowtell David D.L.
Published: August 2018

High-grade serous ovarian cancer (HGSC) was one of the first cancer types subjected to comprehensive genomic analysis, and over the last 5-7 years gene expression and DNA sequence data have been generated from hundreds of samples. A large majority of this data has been obtained from surgical samples collected following primary debulking surgery or following a few cycles of neoadjuvant chemotherapy. By contrast, comparatively little data exist from patients who have been extensively treated with chemotherapy or newer targeted agents, such as antiangiogenics or PARP inhibitors (PARPi). Of particular interest are samples collected from patients whose cancer was initially responsive to treatment but has become resistant to therapy (acquired resistance) at the time of collection.

The presentation will describe data obtained from whole-genome (N=73 samples, 36 patients) and targeted (N=65 samples, 48 patients) sequence analysis of recurrent or end-stage HGSC samples, focusing in particular on two mechanisms of acquired resistance–fusions involving the ABCB1 gene and reversion of germline BRCA1/2 mutations. ABCB1 encodes the multidrug resistance transporter MDR1, also known as P-glycoprotein. Data will be presented on the frequency and mechanisms of ABCB1 deregulation in recurrent HGSC, and approaches to clinical intervention in fusion-positive patients. Reversions in BRCA1/2 appear to render tumors that were defective in homologous recombination (HR) repair, HR proficient and therefore may have important implications for likely treatment response. The presentation will also discuss approaches to evaluating reversion status in patients with mutation in BRCA1/2.

Citation Format: Elizabeth L. Christie, Jessica Beach, Dariush Etemadmoghadam, Dale Garsed, Ann-Marie Patch, Sian Fereday, Swetansu Pattnaik, Australian Ovarian Cancer Study, Samuel Brady, Andrea Bild, David D.L. Bowtell. Acquired chemotherapy resistance in high-grade serous ovarian cancer patients. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr IA12.
Tagesklinische dialektisch-behaviorale Therapie: Eine Verlaufsuntersuchung nach Entlassung. Gibt es Prädiktoren für eine Verschlechterung?
Authors: Richter Christoph
Published: August 2018

Einleitung: Die dialektisch-behaviorale Therapie (DBT) für Patienten mit Borderline-Persönlichkeitsstörung (BPS) ist evidenzbasiert. Es gibt jedoch nur eine kleine Anzahl von Studien, die die Frage einer möglichen anhaltenden Wirkung von DBT untersuchen. Über Prädiktoren dieser Nachhaltigkeit ist wenig bekannt. Methode: Am Beispiel eines zertifizierten tagesklinischen Settings wird der posttherapeutische Verlauf untersucht. Mögliche Prädiktoren einer Verschlechterung nach Therapieende sollen erkannt werden. Hierzu wurden Patienten der DBT-Tagesklinik, deren Daten schon in eine prospektive, naturalistische, offene und nicht kontrollierte Vorstudie eingingen, erneut retrospektiv befragt. Somit konnten die Scores der Borderline-Symptomliste 95 (BSL-95) und des Beck-Depressions-Inventars (BDI) zu 3 verschiedenen Zeitpunkten (Z1 = Start, Z2 = Therapieende, Z3 = Katamnesezeitpunkt) verglichen werden. Der Fragebogen zu «Nebenwirkungen stationärer Psychotherapien» (NESTAP) lieferte weitere mögliche Prädiktoren. Ergebnisse: Der Katamnesezeitraum betrug 3-51 Monate. 82 Patienten wurden angeschrieben, es antworteten 41. Anhand des BDI und der BSL-95 (Differenz Z1 zu Z3, p < 0,05) ist eine Symptombesserung in dieser Gruppe auch weit über das Therapieende feststellbar. In einem linearen Regressionsmodell mit einer Effektstärke von 1,04 (Cohen) zeigt eine Subgruppe (25%), gekennzeichnet durch hohe Werte des Prädiktors «Dysphorie» im BSL-95 (Z2 zu Z1) eine geringe anhaltende Wirkung der DBT (Differenz der BSL-95- und BDI-Scores zu Z2 und Z3). Schlussfolgerungen: Es konnten Hinweise für ein tagesklinisches DBT-Programm zur anhaltenden Symptombesserung bis 51 Monate nach Therapieende dargestellt werden. Für 50% der Patienten ist hierfür keine Aussage möglich. Auch gab es keine Kontrollgruppe. Die Veränderung von «Dysphorie» während der Therapiephase scheint diese therapeutische Wirkung über diesen Katamnesezeitraum zu beeinflussen. Weitere Studien sollten folgen, um die Daten zu prüfen oder andere Prädiktoren zu finden.
Non-Immune Hydrops, Hypotonia, Encephalopathy, and Liver Failure with Novel Compound Heterozygous AHCY Mutations
Authors: Judkins Allison J. , MacQueen Brianna C. , Christensen Robert D. , Comstock Jessica , Mao Rong , Flores-Daboub Josue
Published: August 2018

A late-preterm infant with a prenatal diagnosis of non-immune hydrops was born with hypotonia, poor respiratory effort, chylothorax, encephalopathy, coagulopathy, progressive hepatic failure, and refractory pulmonary hypertension. Life support was withdrawn at 7 days of life due to multisystem organ failure. Rapid whole exome sequencing revealed novel compound heterozygous mutations in the gene encoding S-adenosylhomocysteine hydrolase (AHCY); each novel variant was carried by an asymptomatic parent. Reports of neonates with other AHCY mutations describe a pathology of varying severity. AHCY mutations should be considered when seeking an etiology for neonates with the combination of non-immune hydrops, hypotonia, encephalopathy, and liver failure.
Evaluation of Vascular Changes with Optical Coherence Tomography Angiography after Plaque Radiotherapy of Choroidal Melanoma
Authors: Cennamo Giovanni , Breve Maria Angelica , Velotti Nunzio , Sparnelli Federica , Iovino Claudio , Farella Antonio , Liuzzi Raffaele , de Crecchio Giuseppe , Cennamo Gilda
Published: August 2018

Aim: The purpose of this paper was to evaluate whether optical coherence tomography angiography (OCT-A) can be used to quantify the vascular changes in radiation maculopathy, and changes in the tumor vasculature in eyes treated with plaque radiotherapy for choroidal melanoma. Methods: In this prospective study, we evaluated 39 Caucasian patients with choroidal melanoma (39 eyes) treated with ruthenium-106 plaque radiotherapy. The patients underwent complete ophthalmic examination, bulbar echography, and OCT-A before and 1 year after treatment. Results: At baseline, the mean best-corrected visual acuity (BCVA) in the affected eyes was 0.35 ± 0.40 logMAR, and the mean tumor thickness was 2.68 ± 0.25 mm at A-scan echography. After treatment, the mean BCVA increased to 0.41 logMAR, the mean tumor thickness decreased to 1.66 ± 0.23 mm, and the tumor basal diameter was significantly reduced (U = 108, p = 0.001). Moreover, the capillary vessel density was significantly lower in all Early Treatment of Diabetic Retinopathy Study sectors, and both the vessel and flow areas were significantly reduced (p = 0.030 and p = 0.001, respectively). Conclusions: OCT-A is a noninvasive, reliable method with which to quantify the vessel changes in radiation maculopathy and, given the association between vascularization and malignancy, this procedure may be an aid in treatment decision-making and in monitoring the efficacy of treatment.
Morphological Evaluation of Thyroid Cartilage Invasion in Early Glottic Tumors Involving the Anterior Commissure
Authors: Sava Henrique Wendling , Dedivitis Rogério Aparecido , Gameiro Gustavo Rosa , Pfuetzenreiter Elio Gilberto , de Almeida Ricardo Camillo , Matos Leandro Luongo , Cernea Claudio Roberto
Published: August 2018

Introduction: The anterior commissure is an area of glottic cancer infiltration, even in early stages. Objective: To evaluate the invasion by tumors into the anterior commissure cartilage in surgical specimens of frontolateral laryngectomy. Methods: Forty-eight patients who had undergone frontolateral laryngectomy for T1b/T2 squamous cell carcinoma were included. Epidemiological and clinical aspects as well as morphological histopathological analysis were evaluated. Results: Of the 48 patients, 42 (87.5%) had T1b lesions and 6 (12.5%) had T2. Thirty-four cases (70.8%) showed healthy tissue between the tumor and the thyroid cartilage, 10 cases (20.8%) had a tumor in close proximity to the cartilage, and in 4 cases (8.3%) there was cartilage invasion. There was no major risk of adverse outcome in the groups with infiltration or tumor adjacent to the cartilage. Level of differentiation, mitotic index, nuclear irregularity, and the presence of nucleolus and tumor necrosis were not related to cartilage invasion. Conclusion: The infiltration of thyroid cartilage occurred in 8.3% of tumors and did not change the outcome in patients submitted to frontolateral laryngectomy. The morphological characteristics did not present any statistical significance.
Severe Gastritis after Administration of Nivolumab and Ipilimumab
Authors: Nishimura Yoshito , Yasuda Miho , Ocho Kazuki , Iwamuro Masaya , Yamasaki Osamu , Tanaka Takehiro , Otsuka Fumio
Published: August 2018

Immune checkpoint inhibitors such as ipilimumab, a cytotoxic T-lymphocyte-associated antigen-4 inhibitor, have been widely used for advanced malignancies. As these inhibitors improve antitumor immunity via T-cell modulation, immune-mediated adverse events associated with T-cell activation, such as colitis, might occur. Herein, we describe a 75-year-old Japanese woman with metastatic malignant melanoma who developed hemorrhagic gastritis after ipilimumab treatment. There was no macroscopic or clinical improvement of gastritis after proton pump inhibitor treatment. However, her condition improved after approximately 3 weeks of corticosteroid therapy and Helicobacter pylori eradication. This case suggests a potential association between severe gastritis and immune checkpoint inhibitor treatment. Although several reports have mentioned ipilimumab-associated colitis, gastritis is considered to be rare. In the present case, H. pylori-associated gastritis might have been exacerbated by the T-cell modulation effect of ipilimumab. To date, no report has clarified the mechanism by which ipilimumab modifies H. pylori infection. The present treatment course provides a helpful perspective for similar cases.