bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract LB-384: A-to-I miR-378a-3p editing prevents melanoma progression via regulation ofPARVA expression
Authors: Shoshan Einav , Velazquez-Torres Guermarie , Fuentes-Mattei Enrique , Ivan Cristina , Bar-Eli Menashe
Published: August 2018

Although recent studies have shown that adenosine-to-inosine (A-to-I) RNA editing occurs in microRNAs (miRNAs), the effects of A-to-I miRNAs editing on melanoma growth and metastasis are yet to be determined. Previously we have reported that metastatic melanoma cell lines and tumor specimens have reduced expression of ADAR1 and consequently are impaired in their ability to perform A-to-I microRNA (miRNA) editing. Here we report that miR-378a-3p is undergoing A-to-I editing only in the non-metastatic but not in metastatic melanoma cells. The function of the edited form is different from its wild-type counterpart. The edited form of miR-378a-3p preferentially binds to the 3'UTR of the PARVA oncogene and inhibits its expression, thus preventing the progression of melanoma towards the malignant phenotype. Indeed, edited miR- 378a-3p but not its WT form inhibits melanoma metastasis in vivo. These results further emphasize the role of RNA editing in melanoma progression.

Citation Format: Einav Shoshan, Guermarie Velazquez-Torres, Enrique Fuentes-Mattei, Cristina Ivan, Menashe Bar-Eli. A-to-I miR-378a-3p editing prevents melanoma progression via regulation ofPARVA expression [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 LB-384.
Abstract LB-385: miR-3140 suppresses tumor cell growth by targeting BRD4 via its coding sequence and downregulates the BRD4-NUT fusion oncoprotein
Authors: Muramatsu Tomoki , Tonouchi Erina , Gen Yasuyuki , Hiramoto Hidekazu , Tanimoto Kousuke , Inoue Jun , Inazawa Johji
Published: August 2018

Bromodomain Containing 4 (BRD4) mediates transcriptional elongation of the oncogene MYC by binding to acetylated histones. BRD4 has been shown to play a critical role in tumorigenesis in several cancers, and the BRD4-NUT fusion gene is a driver of NUT midline carcinoma (NMC), a rare but highly lethal cancer. microRNAs (miRNAs) are endogenous small non-coding RNAs that suppress target gene expression by binding to complementary mRNA sequences. Here, we show that miR-3140, which was identified as a novel tumor suppressive miRNA by function-based screening of a library containing 1090 miRNA mimics, directly suppressed BRD4 by binding to its coding sequence (CDS). miR-3140 concurrently downregulated BRD3 by bind to its CDS as well as CDK2 and EGFR by binding to their 3' untranslated regions. miR-3140 inhibited tumor cell growth in vitro in various cancer cell lines, including EGFR tyrosine kinase inhibitor-resistant cells. Interestingly, we found that miR-3140 downregulated the BRD4-NUT fusion protein and suppressed in vitro tumor cell growth in a NMC cell line, Ty-82 cells. Furthermore, administration of miR-3140 suppressed in vivo tumor growth in a xenograft mouse model. Our results suggest that miR-3140 is a candidate for the development of miRNA-based cancer therapeutics.

Citation Format: Tomoki Muramatsu, Erina Tonouchi, Yasuyuki Gen, Hidekazu Hiramoto, Kousuke Tanimoto, Jun Inoue, Johji Inazawa. miR-3140 suppresses tumor cell growth by targeting BRD4 via its coding sequence and downregulates the BRD4-NUT fusion oncoprotein [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 LB-385.
Abstract LB-388: New clinical diagnostic approach for miRNA quantification using the Chlorella virus DNA ligase
Authors: Hynstova Iveta , Mrackova Tereza , Adamcova Michaela , Dvorakova Barbora , Stastna Zlata , Slaby Ondrej , Bartos Milan , Ruzicka Viktor
Published: August 2018

miRNAs have an immense potential to serve as diagnostic, prognostic and prediction biomarkers in the whole field of oncology. Their utilization in liquid biopsy as a non-invasive diagnostic tool is very promising as well. However, to our knowledge, no miRNA-based diagnostics is currently used in clinical laboratories. We believe the reason is simple - the lack of easy, fast, sensitive and reproducible measurement technology, which would have passed the strict clinical validation criteria. On this count we have optimized a very promising miRNA detection technique, utilizing the enzyme Chlorella virus DNA ligase (SplintR® ligase, New England Biolabs), for clinical use. This two-step method involves ligation of two adjacent DNA oligonucleotides hybridized to a miRNA target, followed by TaqMan probe real-time quantitative PCR (qPCR). We managed to reduce the total procedure time from previous 5 hours to 2 hours and 15 minutes maintaining the high sensitivity (1 amol/µl in original clinical sample) and large dynamic range (7 logs). Moreover, we enabled the use of two PCR detection chemistries - more cost-effective SYBR green or more specific TaqMan probe. Based on this optimized method we developed an assay for detection of miR-142-5p, potential marker of colorectal cancer. We measured miR-142-5p profiles in the real samples of whole blood, plasma and serum of healthy donors. The results showed an excellent correlation with the TaqMan qPCR assay and miREIA® immuno-based technology for absolute quantification of miRNA. We conclude, that using SplintR® ligase for miRNA detection is potentially useful for clinical diagnostics.

This work was funded by the Ministry of Industry and Trade of Czech Republic, project No. CZ.01.1.02/0.0/0.0/16_084/0008832.

Citation Format: Iveta Hynstova, Tereza Mrackova, Michaela Adamcova, Barbora Dvorakova, Zlata Stastna, Ondrej Slaby, Milan Bartos, Viktor Ruzicka. New clinical diagnostic approach for miRNA quantification using the Chlorella virus DNA ligase [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 LB-388.
Abstract SY14-01: Determinants of neoantigen immunogenicity
Authors: Delamarre Lelia
Published: August 2018

Genetic instability is a hallmark of cancer, and can lead to accumulation of hundreds of somatic mutations. These mutations, which are unique to each patient, have the potential to be immunogenic if presented on major histocompatibility complex (MHC) molecules and recognized as “non-self” neoantigens by the immune system. There is now compelling evidence that neoantigens have an important role in driving antitumor immunity. Mutational load correlates with clinical response to immune checkpoint blockade therapy in cancer patients. In addition, neoantigen-directed tumor-infiltrating lymphocyte therapy was shown to lead to regression of metastatic lesions in patients. The recent advent of next-generation sequencing technologies has enabled rapid and comprehensive discovery of cancer mutations in individual patients and provides the opportunity to develop novel approaches to selectively target neoantigens. A major challenge, however, is that only a small fraction of the mutations generate T-cell responses. Currently, MHCI binding prediction is used as the major criterion for prioritizing neoantigens. Although this approach enriches for immunogenic neoantigens, a high frequency of false positive remains. For a mutant peptide to be immunogenic, the source protein has to be processed, the resulting mutant peptide needs to bind MHCI, and finally T cells must recognize the MHCI/peptide complex. To investigate the determinants of neoantigen immunogenicity, we performed profiling of the immunopeptidome by mass spectrometry and generated a dataset of immunogenic and nonimmunogenic mutant peptides identified in mouse tumor models by vaccination.

Citation Format: Lelia Delamarre. Determinants of neoantigen immunogenicity [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 SY14-01.
Abstract SY14-02: Personalized therapies: Neoantigen discovery and vaccination
Authors: Bhardwaj Nina
Published: August 2018

Tumor antigens derived from somatic mutations, or indels, are referred to as mutation-derived tumor antigens (MTAs) but are also known as neoantigens,or tumor-specific antigens. Evidence suggests that MTAs play a significant role in the endogenous adaptive immune response to tumors, and in the induced response following treatment with checkpoint inhibitors such as anti-CTLA-4 or anti-PD-1. This session will cover the concept of shared neoantigens in cancer and vaccine approaches to elicit adaptive antitumor immunity.

Citation Format: Nina Bhardwaj. Personalized therapies: Neoantigen discovery and vaccination [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 SY14-02.
Abstract SY17-01: Metabolic impact on immune cell subsets in the tumor microenvironment and its therapeutic relevance
Authors: Zou Weiping
Published: August 2018

We have studied the crosstalk among immune cell subsets (Tregs, Th17, Th22, CD8+ T cells, and APCs) and tumor (stem) cells in the tumor microenvironment, and its impact on tumor immunity and therapy. Over the past few years, our team has achieved important insights into cancer immunopathogenesis. Our research efforts demonstrate that the tumor microenvironment comprises immune cells that have been reprogrammed by active tumor-mediated processes to defeat tumor immunity and promote tumor progression in a highly effective manner. These studies have helped define the nature of immune responses in the cancer microenvironment, form the concept of immunosuppressive networks in the cancer microenvironment, and provide significant insights into designing current immune therapies including inhibitory B7 checkpoint blockade (PD-L1, B7-H1) to treat cancer patients. In this talk, we focus on how glycolysis and oxidative stress affect naïve T cells, effector T cells, and Tregs in the tumor microenvironment. We have demonstrated that tumor-associated glycolysis affects naïve T-cell phenotype via the FIP200-associated autophagy pathway and controls effector T-cell poly-functionality via EZH2-H3K27me3 mediated-epigenetic regulatory mechanism. Furthermore, we have found that tumor Tregs sustain and amplify their suppressor capacity by inadvertent death via oxidative stress. This process is highly regulated through energy metabolism. The work highlights the metabolic pathways controlling T-cell subset functional behavior and affecting cancer immune checkpoint therapy.

Citation Format: Weiping Zou. Metabolic impact on immune cell subsets in the tumor microenvironment and its therapeutic relevance [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 SY17-01.
Abstract SY18-02: The relationship between Batf3-DC and antitumor T-cell responses
Authors: Spranger Stefani
Published: August 2018

Cancer immunotherapy has attracted enormous attention and investment, stimulated by successes of immune checkpoint blockade drugs, such as anti-CTLA4 and anti-PD-1. Despite the potential of immunotherapy to eradicate even metastatic cancer, only a minority of cancer patients respond to checkpoint blockade agents. Clinical and preclinical data provide evidence that the presence of tumor-specific CD8 T cells within the tumor microenvironment (TME) is critical for the response to checkpoint blockade. Another major component of tumor-infiltrating immune systems is the mononuclear phagocytic cell compartment, which provides both pro- and antitumoral properties, depending on its composition. A rare subset of conventional dendritic cells, marked by CD103 and the transcription factor Batf3, is required for the uptake, transport, and presentation of tumor-derived antigens to CD8 T cells in the tumor-draining lymph node. Tumors lacking CD103+ dendritic cells do not mount spontaneous antitumor immune responses and fail to respond to checkpoint blockade therapy. Moreover, we observed that absence of this subset of DC is mediating resistance to adoptive T-cell transfer. Analysis of tumor-residing CD103+ dendritic cells revealed that this small subset of cells provides the predominant source of effector T-cell recruiting chemokines (CXCL9 and 10) and is a critical component of the TME. This observation imposes a more detailed and refined analysis of the contribution of tumor-residing dendritic cells to the local antitumor immune response.

Citation Format: Stefani Spranger. The relationship between Batf3-DC and antitumor T-cell responses [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 SY18-02.
Abstract SY24-02: Improving radio-sensitivity in cervical cancer by targeting tumor metabolism
Authors: Schwarz Julie K.
Published: August 2018

Our group has previously shown that cervical cancers that take up large quantities of glucose, as defined by pretreatment 18F-fluoro-deoxy-glucose positron emission tomography (FDG-PET) imaging, are resistant to standard-of-care treatment (cisplatin plus concurrent pelvic irradiation). In this session, we will review the clinical evidence that supports this finding, and translational studies that support a connection between aberrant PI3K/AKT signaling and increased glucose uptake in tumors. We will then detail recent preclinical evidence that supports simultaneous inhibition of glycolysis and redox metabolism as an effective and safe alternative treatment strategy for highly glycolytic, radiation-resistant cervical cancers. Ongoing efforts to identify, characterize, and validate biomarkers to guide this strategy will be discussed.

Citation Format: Julie K. Schwarz. Improving radio-sensitivity in cervical cancer by targeting tumor metabolism [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 SY24-02.
Abstract SY28-01: Management of MAP kinase and apoptosis signaling thresholds by microRNAs
Authors: Derry W. Brent
Published: August 2018

An important problem in cancer biology is concerned with how apoptotic thresholds are established. Defective regulation of apoptosis can cause resistance to chemotherapeutic agents and radiation therapy, which highlights the need to resensitize these tumors to therapy. The apoptosis pathway was first elucidated in the roundworm Caenorhabditis elegans, and studies in this organism continue to uncover regulatory mechanisms that are also conserved in humans. By taking advantage of the powerful genetics, cell biology, and proteomics tools of C. elegans, we seek to understand how apoptotic signaling is fine-tuned in response to ionizing radiation (IR). Our work has uncovered a network of regulatory mechanisms, such as ubiquitin proteolysis and microRNAs, that control the levels of apoptotic proteins. I will discuss our recent efforts to understand how microRNA 35 (mir-35) antagonizes translation of the BH3-only protein EGL-1 and the Ras/MAPK effector NDK-1 in response to IR. EGL-1 is homologous to human PUMA and NDK-1 is the worm orthologue of human NME1 (NME/NM23 nucleoside diphosphate kinase 1), which has been shown to regulate MAPK signaling in both worms and human cells. mir-35 normally functions to buffer IR-induced apoptosis through its combinatorial effects on EGL-1 and NDK-1 translation. Ablation of mir-35, or mutations in the mir-35 binding sites in the 3'-untranslated region (3'UTR) of egl-1 and ndk-1, increase the levels of these proteins and cause hypersensitivity to IR-induced apoptosis. By targeting both the core apoptosis pathway and the MAPK cascade, we propose that mir-35 plays a key role in fine-tuning apoptotic signaling in order to protect healthy cells and ensure a rapid response to DNA-damaging agents. Given the high conservation in the organization of these pathways from C. elegans to human, manipulating microRNAs might help resensitize tumors that have developed resistance to radiation and/or chemotherapy.

Citation Format: W. Brent Derry. Management of MAP kinase and apoptosis signaling thresholds by microRNAs [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 SY28-01.
Abstract SY35-01: Systematic approaches to identify cancer dependencies
Authors: Hahn William C.
Published: August 2018

We now have a draft view of the genetic alterations that occur in human cancer, and molecular profiling of cancers provides the means to identify therapeutic agents for some patients. However, the number of mutations found at low frequency, the molecular heterogeneity of most cancers, and the lack of therapeutic agents specific for many cancer drivers limit the application of precision medicine in many patients. To complement genome characterization studies, we have used genome-scale gain- and loss-of-function approaches to identify genes required for cell survival and transformation. Specifically, we have performed systematic studies to interrogate rare alleles found altered in cancer genomes and used advances in synthetic gene synthesis to prospectively interrogate all possible alleles of known cancer genes. In parallel, we have performed both genome-scale RNAi and CRISRP-Cas9 screens in more than 800 cancer cell lines to identify differentially essential genes and the context that specifies gene dependency. These studies allow us to define a global cancer dependencies map, which will help further operationalize precision cancer medicine.

Citation Format: William C. Hahn. Systematic approaches to identify cancer dependencies [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 SY35-01.
Abstract SY37-03: Mitochondrial genetic contributions to metastatic efficiency
Authors: Welch Danny R.
Published: August 2018

Complex phenotypes, like tumorigenicity or metastasis, require coordinated expression of multiple genes. Additionally, the contributions of some of those genes can be affected by polymorphisms in the protein coding or regulatory sequences (PMID: 22257951). The pathobiology of metastasis remains poorly understood because both intrinsic (i.e., genetic) and extrinsic (i.e., tumor-microenvironment interactions) are involved. A growing body of data indicates demonstrate that there are underlying genetic components that govern the processes involved in cancer spread and colonization. To assess the contributions of mitochondrial genetics in metastasis, we created Mitochondrial Nuclear Exchange (MNX) mice by transferring an oocyte nucleus from strainx into an enucleated oocyte from strainy, and showed that mammary tumor formation and metastasis are regulated by inherited mitochondrial polymorphisms in an oncogenic driver-dependent manner (PMID: 26471915; PMID: 29070615). Since stromal compartments also possess changed mitochondria in the MNX mice, we hypothesized that mitochondrial polymorphisms in non-cancer cell compartments could exert effects on tumor formation and/or metastasis in addition to genetic (cell autonomous) changes. Syngeneic tumor cells were injected into MNX mice with the same nuclear, and therefore same MHC, background. Experimental metastasis was compared between wild-type and MNX mice (i.e., with same or different mtDNA backgrounds, respectively). E0771 mammary carcinoma and B16-F10 melanoma cells (both syngeneic to C57BL/6J), formed significantly (P<0.01) more lung metastases in C57BL/6J-mtMNX(C3H/HeN). K1735-M2 melanoma cells (syngeneic to C3H/HeN) formed significantly (P<0.05) fewer lung metastases in C3H/HeNmtMNXC57BL/6J. These results have been replicated ≥3 times using >10 mice per experiment. C57BL/6J mitochondria confer resistance to metastasis in both cell autonomous and non-cell autonomous experiments. Basal metabolic and ROS differences comparing mouse embryonic fibroblasts isolated from wild-type and MNX mice are among mechanisms being explored. Differential gene expression occurred in tissues isolated from wild-type and MNX mice (PMID: 28663334). Additionally, altered immune and microbiota profiles have been observed. Together, our findings highlight striking influences that mitochondrial haplotypes can exert on tumorigenicity and metastasis via both intrinsic and extrinsic mechanisms.

Support: Susan G. Komen for the Cure (SAC11037), Natl Fndn Cancer Res. and CA168524.

Citation Format: Danny R. Welch. Mitochondrial genetic contributions to metastatic efficiency [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 SY37-03.
Abstract SY40-01: In vivo genetic screens for genes that modulate tumor immunity
Authors: Haining W Nicholas
Published: August 2018

Despite the dramatic clinical success of cancer immunotherapy with PD-1 checkpoint blockade, most patients do not experience sustained clinical benefit from treatment, suggesting that additional therapeutic strategies are needed. To discover new immunotherapy targets, we developed a pooled, loss-of-function in vivo genetic screening approach using CRISPR/Cas9 genome editing in mouse transplantable tumors treated with vaccination and PD-1 checkpoint blockade. We tested 2,400 genes expressed by melanoma cells for those that synergize with or cause resistance to checkpoint blockade, and recovered the known immune evasion molecules, PD-L1 and CD47. Loss of function of genes required to sense interferon-γ caused resistance to immunotherapy. Deletion of Ptpn2, a pleotropic protein tyrosine phosphatase, improved response to immunotherapy. Cellular, biochemical, transcriptional, and genetic epistasis experiments demonstrated that loss of function of Ptpn2 sensitizes tumors to immunotherapy by enhancing interferon-γ-mediated effects on antigen presentation and growth suppression. Thus, strategies that increase interferon-γ sensing by tumor cells could improve the efficacy of immunotherapy. More generally, in vivo genetic screens in tumor models can identify new immunotherapy targets, model resistance mechanisms, and may accelerate the rational selection of combination immunotherapy.

Citation Format: W Nicholas Haining. In vivo genetic screens for genes that modulate tumor immunity [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 SY40-01.
Abstract SY43-01: Coordinated gene expression mediated by RNA modifications
Authors: Agami Reuven
Published: August 2018

Gene transcription and mRNA translation are two main pillars of gene expression. Due to the different timings, spots of action, and mechanisms of regulation, these processes are mainly regarded as distinct and generally uncoupled, despite serving a common purpose. We identified that the rate of transcription regulates the efficacy of translation. We show that RNA modification, in the form of N6-adenosine methylation (m6A), is co-transcriptional and depends on the dynamics of RNA transcription. Altogether, our study uncovered a general and widespread link between transcription and translation that is governed by epigenetic modification of mRNAs. We postulate that this mechanism will play a role in cancer-related processes.

Citation Format: Reuven Agami. Coordinated gene expression mediated by RNA modifications [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 SY43-01.
Abstract A57: Antisense oligonucleotide therapeutics with receptor-targeted delivery in triple-negative breast cancer cells via microRNA blockade without passenger strand side effects
Authors: Jin Yuan-Yuan , Wickstrom Eric
Published: August 2018

Triple-negative breast cancer (TNBC) attacks >40,000 young women annually in the US, and has no molecular targeted therapies. MicroRNAs drive many forms of cancer, and they modulate multiple gene pathways simultaneously. Highly expressed microRNA miR-17-5p is distinctive in TNBC and contributes to cancer cell survival. We hypothesized that reduction of miR-17-5p activity by delivering oligonucleotide-based antagomiRs specifically to breast cancer cells via receptor-mediated endocytosis would inhibit metastatic behavior of TNBC cells.

Using a luciferase reporter system harboring a miR-17-5p binding site in the 3′ untranslated region of the luciferase gene, we assessed the efficacy of various antagomiRs. Contrary to conventional wisdom, that only one of the two strands in a pre-miRNA duplex is active, such as miR-17-5p, we previously observed that a full-length miR-17-5p DNA-LNA blocker created additional off-target effects by mimicking miR-17-3p, implying that therapeutic microRNA blockers should be designed to avoid resemblance to the opposing strands. We designed guide strand specific blockers of miR-17-5p composed of gapmers with anionic backbone derivatives 2′-fluoro-arabino nucleic acid (FANA), and 2′-aminomethyl-bridged nucleic acid (NC-BNA). Since most breast cancer cells overexpress insulin-like growth factor receptor (IGF1R), a peptide derivative of the IGF1 was conjugated to anti-miR-17-5p antagomiRs to achieve breast cancer cell-specific delivery.

Our results showed that in multiple TNBC cell lines, the NC-BNA 15mers displayed high efficacy with sub-nM activity for miR-17-5p blockade and significant inhibition of cell growth. Anti-miR-17-5p-IGF1 peptide conjugate successfully inhibited miR-17-5p activity in the luciferase reporter system. We are further examining the effects of NC-BNA-peptides in multiple TNBC cell lines. Our study provides a good basis for the development of a new TNBC targeted therapy. Supported by Bound Therapeutics LLC. Conflict of interest: pending TJU PCT/US2015/015681 patent application licensed to Bound Therapeutics LLC.

Citation Format: Yuan-Yuan Jin, Eric Wickstrom. Antisense oligonucleotide therapeutics with receptor-targeted delivery in triple-negative breast cancer cells via microRNA blockade without passenger strand side effects [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 A57.
Abstract B02: Intratumoral bidirectional transitions between epithelial and mesenchymal cells in triple-negative breast cancer
Authors: Yamamoto Mizuki , Inoue Jun-ichiro
Published: August 2018

Epithelial-mesenchymal transition (EMT) and its reverse process, MET, are crucial in cancer metastasis. EMT allows cancer cells to move to proximal blood vessels for intravasation. However, because EMT and MET processes are dynamic, mesenchymal cancer cells are likely to undergo MET to form metastatic foci and subsequently re-undergo EMT to restart the metastatic process. To elucidate such regulation, we chose HCC38, a human triple-negative breast cancer (TNBC) cell line, because HCC38 is composed of epithelial and mesenchymal populations. We purified epithelial and mesenchymal cells from Venus-labeled and unlabeled HCC38 and mixed them at various ratios to follow EMT and MET. Using this system, we demonstrate that the two populations significantly enhance the transition of cells from the other population to their own. In addition, knockdown of ZEB1 or SLUG significantly suppressed EMT but promoted partial MET. We also demonstrate that primary breast cancer cells underwent EMT. These changes were very similar to those observed in EMT in HCC38. Consequently, we propose HCC38 as a suitable model to analyze EMT-MET dynamics that could affect development of TNBC.

Citation Format: Mizuki Yamamoto, Jun-ichiro Inoue. Intratumoral bidirectional transitions between epithelial and mesenchymal cells in triple-negative 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 B02.
Abstract B17: Activating AMPK signaling by SCT-1015 to suppress tumor growth on triple negative breast cancer cells
Authors: Su Jung-Chen , Huang Jui-Wen , Shiau Chung-Wai
Published: August 2018

AMPK (AMP-activated protein kinase) is one of the central regulators of cellular and organismal metabolism that has been linked to the regulation of tumor progression; however, its biologic functions and signaling cascades remain unclear. Recently, many AMPK activators, including metformin, phenformin, and nilotinib, have shown anticancer efficacy. Nilotinib is a small-molecule tyrosine kinase inhibitor approved for the treatment of imatinib-resistant chronic myelogenous leukemia (CML).

In our previous study, we found that nilotinib increased AMPK phosphorylation and led to autophagic cell death in human hepatocellular carcinoma (HCC) cells. To dissect the involvement of Bcr-Abl kinases in nilotinib-mediated cell death in human TNBC cells, we designed a series of new compounds, with structure similar to nilotinib but without hinge-binding activity in the ATP binding pocket of kinases.

In this work, we found one of the nilotinib analogues, SCT-1015, showed better efficacy on AMPK activation and cell death induction compared to nilotinib without inhibiting Bcr-Abl kinase in human TNBC cells. Moreover, we demonstrate that SCT-1015 increased AMPK phosphorylation and inhibited cell proliferation in TNBC. Importantly, SCT-1015 suppressed tumor growth in HCC1806 orthotopic mice model. Our study indicates that targeting AMPK signaling pathway may be a useful approach for the development of targeted agents for anti-breast cancer.

Citation Format: Jung-Chen Su, Jui-Wen Huang, Chung-Wai Shiau. Activating AMPK signaling by SCT-1015 to suppress tumor growth on triple negative 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 B17.
Abstract B22: Inducing cell state transitions in triple-negative breast cancer (TNBC)
Authors: Loo Ser Yue , Toh Liping , Pathak Elina , Tan Wilson , Ma Siming , Yuan Ju , Periyasamy Giridharan , Torta Federico , Chan Jack , Tan Tira , Sim Yi Rong , Tan Veronique , Tan Benita , Madhukumar Preetha , Yong Wei Sean , Ong Kong Wee , Wong Chow Yin , Wenk Markus R. , Foo Roger , Yap Yoon-Sim , Lim Elaine , Tam Wai Leong
Published: August 2018

Triple-negative breast cancer (TNBC), as immunohistochemically defined by its estrogen receptor (ER)-negative, progesterone receptor (PR)-negative and human epidermal growth factor receptor-2 (HER2)-negative status, is an important subtype due to its biologically aggressive behavior and limited treatment options available. TNBC is associated with an overall poorer prognosis, with higher risk of disease recurrence/progression and shorter duration of treatment response, i.e., treatment resistance. Treatment resistance may be largely attributed to cancer stem cells (CSCs), which are intrinsically treatment resistant and continually self-renew, proliferate, and differentiate into different phenotypes. Activation of the cell biologic program, epithelial-mesenchymal transition (EMT), has been demonstrated to promote the dedifferentiation of heterogeneous subpopulations of cancer cells towards CSC phenotypes. We hypothesized that induction of the mesenchymal-epithelial transition (MET) program might disrupt CSC function, drive differentiation, and render greater susceptibility to conventional chemotherapy. In this study, we utilized high-throughput chemical-genetic screens to uncover a potent class of MET mediators. With the use of in vitro and in vivo models of TNBC, we showed that changing the malignant cell state to a differentiated phenotype by inducing MET reduced mammosphere formation, increased chemosensitivity, and decreased the tumor burden in NSG mice. Delving into the mechanisms of tumor differentiation via ChIP-seq, RNA-seq, and Gene Ontology analysis revealed differences in metabolic status between cell states, which might be exploited in the treatment of TNBC. We also assessed combinations of MET mediators, in order to increase the potency and durability of differentiation. Hence, this study assessed the role of differentiation in the treatment of TNBC and the efficacy of various MET mediators, singly and in combination, in inducing differentiation.

Citation Format: Ser Yue Loo, Liping Toh, Elina Pathak, Wilson Tan, Siming Ma, Ju Yuan, Giridharan Periyasamy, Federico Torta, Jack Chan, Tira Tan, Yi Rong Sim, Veronique Tan, Benita Tan, Preetha Madhukumar, Wei Sean Yong, Kong Wee Ong, Chow Yin Wong, Markus R. Wenk, Roger Foo, Yoon-Sim Yap, Elaine Lim, Wai Leong Tam. Inducing cell state transitions in triple-negative breast cancer (TNBC) [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 B22.
Abstract B34: Novel synergistic combination therapies with BET bromodomain inhibitors in triple-negative breast cancer
Authors: Bevill Samantha M. , Sciaky Noah , Golitz Brian T. , Rashid Naim U. , Zawistowski Jon S. , Johnson Gary L.
Published: August 2018

Adaptive resistance to targeted cancer therapies is a universal problem in cancer treatment where tumor cells circumvent targeted pathway inhibition to reactivate growth signaling. In our previous work, we observed genome-wide enhancer remodeling following MEK inhibition (MEKi) capable of driving adaptive gene transcription in triple-negative breast cancer (TNBC). Adaptive enhancers were enriched for the BET bromodomain protein BRD4 and cotreatment with MEKi and BET inhibitor (JQ1) could durably suppress TNBC growth in multiple cell lines and preclinical mouse models. There are currently 10 BET inhibitors in clinical trials being tested as single agents across multiple tumor types including TNBC. There is also a growing body of preclinical literature using epigenetic inhibitors to block the adaptive ability of tumor cells in combination with multiple targeted therapies. This led us to screen for inhibitors that synergize with JQ1 to suppress growth of TNBC using a 176-compound library enriched for epigenetic and kinase inhibitors. We performed synergy screens in 6 TNBC cell lines across 6 doses of JQ1 and each library compound. Using the Bliss Independence model to assess synergy, we found that inhibition of MEK, CDK9, Aurora Kinase, CREBBP/P300, and BAZ2A/B was strongly synergistic with JQ1. BRD4, CDK9, and the acetyltransferase CREBBP/P300 are all members of the P-TEFb transcriptional elongation complex. When we performed additional synergy screens against the P300 bromodomain inhibitor CPI-637, we found a significant overlap in synergistic targets with the JQ1 screen including MEK, BET bromodomain proteins, ERK, Aurora Kinase, and CDK9. BAZ2A/B inhibition using the small-molecule inhibitor GSK2801, which targets the bromodomain of BAZ2A/B, synergized significantly stronger with JQ1 across all cell lines compared to CPI637. BAZ2A/B proteins are members of nucleosome remodeling complexes that mediate DNA silencing by aiding in recruitment of histone modifying enzymes. Ongoing studies seek to understand the role of BAZ2A/B and the mechanism of GSK2801 synergy with BET bromodomain inhibition using RNA sequencing and ChIP sequencing experiments. These results define novel targets that synergize with JQ1 to suppress tumor cell growth and illuminate additional mechanisms of transcriptional regulation driven by BET bromodomain proteins in TNBC.

Citation Format: Samantha M. Bevill, Noah Sciaky, Brian T. Golitz, Naim U. Rashid, Jon S. Zawistowski, Gary L. Johnson. Novel synergistic combination therapies with BET bromodomain inhibitors in triple-negative 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 B34.
Abstract B38: The role of BQ323636.1, a novel splice variant of NCOR2, in modulation of oxidative stress in breast cancer
Authors: Leung Man Hong , Tsoi Ho , Man Ellen Pui Sum , Lam Eric Wing-Fai , Khoo Ui Soon
Published: August 2018

Breast cancer is the most common type of female cancer. Reactive oxygen species (ROS) plays an important role in the signaling pathways governing survival and proliferation of breast cancer cells. Several chemotherapeutic drugs, such as taxanes, platinum compounds, and anthracyclines, induce cell death by enhancing the levels of ROS. Nuclear factor erythroid 2-related factor 2 (NRF2) is the master transcription factor regulating antioxidative responses against ROS. Overexpression of NRF2 has been found in breast cancer and it modulates oxidative stress response, leading to drug resistance in cancers. Our previous splice array study identified a novel splice variant of NCOR2, BQ323636.1 (BQ), as predictor of tamoxifen resistance in breast cancer. In the current study, we show overexpression of BQ could promote cell proliferation and protect cells from oxidative stress. In addition, overexpression of BQ could reduce the levels of ROS in breast cancer cells. We therefore hypothesized that BQ could compromise oxidative stress via the NRF2 pathway. By qPCR assay, several downstream targets of NRF2 were found to be upregulated in BQ-overexpressing cells. This suggested that NRF2 transcriptional activity could be modulated by BQ. The results from luciferase reporter assay confirmed that NCOR2 could repress the transcriptional activity via antioxidant response element (ARE), the primary binding site of NRF2 in promoter region. BQ could reverse the repressive effect of NCOR2 on ARE, suggesting that BQ might modulate NRF2 activity via NCOR2. Co-immunoprecipitation indicated NCOR2 interacted with NRF2. BQ overexpression might inhibit such an interaction. Taken together, our results suggest that BQ regulates NRF2 signaling pathway via interfering with NCOR2 activity. Our findings reveal a novel role for BQ as a modulator of NRF2 and oxidative stress in breast cancer.

Citation Format: Man Hong Leung, Ho Tsoi, Ellen Pui Sum Man, Eric Wing-Fai Lam, Ui Soon Khoo. The role of BQ323636.1, a novel splice variant of NCOR2, in modulation of oxidative stress 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 B38.
Abstract B41: BP1 is an important biomarker in breast cancer
Authors: Berg Patricia E. , Man Yan-gao , Simmens Samuels , Fu Sidney W. , Cavalli Lucianne , Vesuna Farhad , Kirolikar Saurabh , Schwartz Arnold
Published: August 2018

Beta protein 1 (BP1), a transcription factor (TF) we identified and cloned, is encoded by a homeobox gene called DLX4. BP1 is overexpressed in breast cancer, prostate cancer, ovarian cancer, acute myeloid leukemia, non-small cell lung cancer, and possibly other malignancies as well. Important characteristics of BP1 in breast cancer, a focus in our laboratory, include findings that: (1) BP1 is expressed in 80% of invasive ductal breast tumors, including 89% of the tumors of African American women. These data are based on both RNA and protein data. (2) BP1 expression correlates with the progression of breast tumors, from 0% in normal breast tissue to 21% in hyperplasia and 46% in ductal carcinoma in situ. (3) BP1, which maps to 17q21, can be activated by DNA amplification. (4) BP1 appears to be associated with metastasis. Forty-six cases of inflammatory breast cancer were examined; all were positive for BP1 expression. Nine cases had metastasized; lymph nodes from all nine were also BP1 positive. Moreover, BP1 activates a known trigger of metastasis, the Twist gene. (5) BP1 overexpression induces oncogene expression. BP1 activates the BCL-2 gene; high BCL-2 protein levels are associated with resistance to drug and radiation therapy. BP1 also activates VEGF and c-MYC, as well as other genes important in angiogenesis, invasion, and metastasis. (6) Cells overexpressing BP1, when injected into the fat pads of nude mice, were associated with larger and more frequent tumors than found in control mice receiving cells with low BP1. In summary, BP1 appears to confer properties on breast cancer cells that lead to a more invasive and aggressive phenotype. Since the functions of homeotic transcription factors are highly conserved, it is possible that BP1 regulates many of the same processes and genes in other malignancies in which it is active.

Citation Format: Patricia E. Berg, Yan-gao Man, Samuels Simmens, Sidney W. Fu, Lucianne Cavalli, Farhad Vesuna, Saurabh Kirolikar, Arnold Schwartz. BP1 is an important biomarker 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 B41.
Abstract IA14: Breast tumor evolution: The role of the microenvironment
Authors: Polyak Kornelia
Published: August 2018

The immune system and the tissue microenvironment shape tumor evolution by providing selection for cancer cells with certain phenotypes. Immunotherapy is one of the most promising current cancer therapies and one of the very few that has the potential to cure even advanced metastatic disease. However, in breast cancer its success thus far has been limited to a subset of triple-negative tumors. This could be due to the testing of a limited set of immune-regulatory agents, but also a consequence of heterogeneity among tumors for mechanisms by which they escape immune surveillance. We hypothesized that the in situ to invasive carcinoma transition is a critical step for immune escape in breast cancer, since in DCIS (ductal carcinoma in situ) cancer cells are still physically separated from the stroma by the basement membrane and myoepithelial cell layer, and tumor-infiltrating leukocytes are rarely detected in direct contact with cancer cells. In contrast, in invasive tumors cancer cells and leukocytes are mixed, providing a strong selection for cancer cells that can overcome a potential immune attack. To begin dissecting mechanisms of immune escape during breast tumor evolution, we analyzed the composition of leukocytes in normal breast tissues, DCIS, and invasive ductal carcinomas (IDC) by a combination of technologies including FACS, RNA-seq, multicolor immunofluorescence, and immune-FISH. Based on these analyses, we found that invasive tumors have a less active immune environment due to a combination of upregulation of immune-suppressive mechanisms by both the cancer cells and various other cell types composing the microenvironment. Our results will improve our understanding of immune escape in breast cancer and aid the design of more effective immunotherapies for both advanced and early-stage disease.

Citation Format: Kornelia Polyak. Breast tumor evolution: The role of the microenvironment [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 IA14.
Abstract IA19: Homologous recombination repair deficiency and breast cancer progression in high-risk populations
Authors: Olopade Olufunmilayo I.
Published: August 2018

Analysis of cancer genomes has rapidly become an integral part of the practice of clinical oncology, with implications for diagnosis, prognosis, treatment, and prevention. Inherited and sporadic cancers often share common mutational events. When inherited mutations are identified, genetic counseling is an essential component of care. Pathogenic BRCA1 and BRCA2 mutations are the strongest predictors of breast cancer risk and may be the strongest predictors of other inherited forms of solid tumors and hematologic malignancies as well. Waiting to treat advanced breast cancer with targeted therapies is a failure of primary prevention, and population-based strategies for risk management in high-risk populations will be needed. Understanding breast cancer progression in genetic defined subgroups has the potential to accelerate progress in precision medicine. I will discuss ongoing research in our group, our recent findings in defining the genomic landscape of early-onset breast cancer, and future directions for the early detection, treatment, and prevention of breast cancer in high-risk populations.

Citation Format: Olufunmilayo I. Olopade. Homologous recombination repair deficiency and breast cancer progression in high-risk populations [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 IA19.
Abstract 02: BCL-W significantly contributes to B-cell lymphoma survival and development
Authors: Adams Clare M. , Mitra Ramkrishna , Gong Jerald Z. , Kim Annette S. , Choi John K. , Eischen Christine M.
Published: August 2018

The ability of cells to undergo apoptosis in response to cellular stresses functions as a safeguard against tumorigenesis. Consequently, compromised apoptotic signaling must precede tumor development. To design effective therapies for cancer treatment, the underlying mechanisms that govern cell survival need to be understood. The anti-apoptotic proteins of the Bcl-2 family are key regulators of cell survival and are frequently overexpressed in malignancies, leading to increased cancer cell survival. Bcl-w, the closest anti-apoptotic relative to Bcl-2 and Bcl-xL, is essential for spermatogenesis, but was considered dispensable for other cell types. However, we recently uncovered a significant role for Bcl-w in B-cell survival and lymphomagenesis. Specifically, loss of Bcl-w conferred sensitivity to growth factor deprivation-induced B-cell apoptosis. In addition, apoptosis triggered by hyperproliferative signals from the Myc oncogene was accentuated by loss of Bcl-w. Consequences of elevated apoptosis were observed in vivo, as Bcl-w loss profoundly delayed Myc-mediated B-cell lymphoma development. We also determined Myc regulates Bcl-w expression through its transcriptional regulation of the miR-15 family. Importantly, evaluation of Burkitt lymphoma (BL) patient samples revealed BCL-W overexpression was highly selected for, and that targeting BCL-W using multiple methods induced apoptosis of BL cells. In addition, overexpression of BCL-W in BL cell lines conferred resistance to the BH3-mimetics ABT-737 and ABT-263 that inhibit anti-apoptotic BCL-2 family members. Furthermore, BCL-W was overexpressed in diffuse large B-cell lymphoma (DLBCL) and correlated with decreased patient survival. Analysis of multiple data sets of other aggressive and indolent B-cell lymphomas showed that BCL-W was frequently overexpressed in them as well. Collectively, our data indicate that BCL-W is an understudied contributor to B-cell lymphoma development and survival that appears to be as important as BCL-2 to B-cell lymphomas. In addition, BCL-W is a predictive biomarker that could improve prognostication and the development of more effective treatment strategies for B-cell lymphomas.

Citation Format: Clare M. Adams, Ramkrishna Mitra, Jerald Z. Gong, Annette S. Kim, John K. Choi, Christine M. Eischen. BCL-W significantly contributes to B-cell lymphoma survival and development [abstract]. In: Proceedings of the Second AACR Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; May 6-9, 2017; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(24_Suppl):Abstract nr 02.