bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract LB-179: The feasibility of delivering a cancer education program in correctional facilities
Authors: Valera Pamela , Mackey Daniel , Lian Zi , McLaughlin William
Published: August 2018

Introduction. Cancer 101, a cancer education program, is a critical resource to increase cancer knowledge, awareness, and cancer prevention activities to improve cancer health and survival rates. The purpose of this study was to test the feasibility of delivering the Cancer 101 curriculum to incarcerated adult males to improve cancer knowledge and increase cancer prevention activities.

Methods. Cancer 101 curriculum was pilot tested for adaptation with representatives from the target audience in a New York and Pennsylvania prison facilities and based on their feedback modifications were implemented. Three prison facilities participated in adapting Cancer 101 for this study; participation in the Cancer 101 educational intervention was limited to individuals who were current smokers or former smokers. Pre-test and post-test surveys were used to assess knowledge of, perceived attitudes regarding and benefits of cancer prevention activities at baseline and immediately after completing the Cancer 101 educational intervention. To determine whether cancer knowledge improved after participating in the Cancer 101 program, a paired t-test procedure was conducted; since improvement was expected, a one-tailed alpha of .05 was specified.

Results. The mean cancer knowledge scores differed prior to and after completing the Cancer 101 intervention, t(165) = -14.65, p < .000. Mean cancer knowledge scores prior to the Cancer 101 intervention (M = 28.42, SD = 4.21) were significantly lower than after the intervention (M = 32.68, SD = 3.36). Therefore, the intervention had a positive effect on cancer knowledge. Participants also reported that the primary reasons for participating in the Cancer 101 intervention were to develop knowledge about cancer and the skills to participate in cancer prevention activities and to educate other inmates and family members about cancer. Participants demonstrated significant increases in cancer knowledge and interest in partaking in cancer prevention activities.

Discussion. A prison-based Cancer 101 educational intervention provides opportunities for inmates to increase cancer knowledge, as well as promote action for cancer control during incarceration.

Citation Format: Pamela Valera, Daniel Mackey, Zi Lian, William McLaughlin. The feasibility of delivering a cancer education program in correctional facilities [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-179.
Abstract LB-242: PTEN regulates mitotic checkpoint complex during mitotic progression
Authors: Choi Byeong Hyeok , Xie Steve , Dai Wei
Published: August 2018

PTEN is a well-known tumor suppressor through the negative regulation of the PI3K signaling pathway. Recently, it has been reported that nuclear PTEN plays an important role in cellular function. To understand the molecular basis by which PTEN mediates mitotic progression, we examined whether PTEN regulated the formation of mitotic checkpoint complex (MCC). Here we observed that arsenic trioxide, a mitotic inducer, stimulated nuclear translocation of PTEN in a time-dependent manner. PTEN physically interacted with Cdc20 and Mad2, two important components of MCC. Arsenic treatment diminished the physical association of PTEN with BubR1 and Bub3 but not with Cdc20 and Mad2. Our further studies revealed that downregulation of PTEN via RNAi enhanced formation of MCC during the cell cycle. Moreover, PTEN silencing induced chromosomal instability. Given the crucial role of PTEN in suppressing tumor development, our study strongly suggests that PTEN also functions to maintain chromosomal stability, partly through suppressing unscheduled formation of MCC.

Citation Format: Byeong Hyeok Choi, Steve Xie, Wei Dai. PTEN regulates mitotic checkpoint complex during mitotic progression [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-242.
Abstract LB-248: Chemically distinct class I HDAC inhibitors synergize to inhibit global lipid metabolism in cancer
Authors: Mahmud Iqbal , Garrett Timothy J. , Stowe Ryan , Roush William R. , Liao Daiqing
Published: August 2018

An increased rate of lipid production is a hallmark metabolic feature in cancer cells, which provides energy supplies, building blocks for membrane biogenesis, and signaling molecules for increased cancer cell proliferation. Current chemotherapeutic strategies targeting lipid metabolism have shown significant limitations, and as such, there is great interest in discovering novel therapies that effectively inhibit lipid production in cancer cells. Class I histone deacetylases (HDACs 1-3) are a key component of the epigenetic machinery regulating gene expression, and behave as oncogenes in several cancer types, spurring the development of HDAC inhibitors (HDACi) as novel anticancer drugs. Interestingly, HDAC inhibitors (HDACi) have been shown to decrease lipid production in different cells by modulating key genes in cholesterol synthesis, uptake, and efflux. However, effects of HDACi in lipid biosynthesis of cancer remains poorly studied. We have discovered a novel class of HDACi with a previously undescribed benzoylhydrazide scaffold. These new inhibitors are highly selective and potent to the class I HDACs (HDAC1, HDAC2, and HDAC3). Using global lipidomics approach by Ultra High-Performance Liquid Chromatography coupled High-Resolution Mass Spectrometry (UHPLC-HRMS), we found that a novel optimized analog, SR-4370, exhibits potent inhibition of lipid production in cells of diverse cancer types. Strikingly, SR-4370 in combination with entinostat, a benzamide analog of class I HDAC inhibitor currently in multiple clinical trials for treating breast cancer and other types of solid tumors, exhibits synergistic effects on inhibition of lipid production in cancer cells. We will present lipidomic profiling data from cells and xenograft tumors after treatment with SR-4370/entinostat, and discuss mechanisms of action for these distinct HDACi in inhibiting lipid production. In summary, our findings provide a rationale for inhibiting lipogenesis using isoform-selective HDACi in cancer therapy.

Citation Format: Iqbal Mahmud, Timothy J. Garrett, Ryan Stowe, William R. Roush, Daiqing Liao. Chemically distinct class I HDAC inhibitors synergize to inhibit global lipid metabolism in 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 LB-248.
Abstract LB-267: A small molecule mimic approach to the PEDF/LAMR1 interaction in prostate cancer
Authors: Edwards Daniel F. , Umbaugh Charles S. , Figueiredo Marxa L.
Published: August 2018

Pigment epithelium derived factor, or PEDF, is a well-known and potent inhibitor of angiogenesis. Our lab as well as others have examined PEDF as a novel prostate cancer therapy, as PEDF inhibits tumor establishment, promotes tumor cell differentiation, and induces tumor apoptosis. PEDF has been identified as a binding partner for the cancer associated protein Laminin Receptor (LAMR1). LAMR1 has been shown to be overexpressed in several types of cancers including breast, colon, and prostate. It has been reported in the literature that the PEDF/LAMR1 interaction inhibits tumor migration and invasion. Recent work in the lab investigated whether we could mimic the PEDF/LAMR1 interaction using a small molecule approach.

Utilizing a 14,400 compound in-silico screen, we identified several small molecules as potential binders to the PEDF interaction interface of LAMR1. From those, we identified a hit compound with anti-proliferative capacity against several prostate cancer cell lines. In PC-3 cells, our hit compound showed activation of anti-tumor signaling and altered proteins associated with prostate cancer and DNA maintenance through LAMR1. We recently tested our hit compound as well as several structural analogs in PC-3 cells at 10 and 50 uM in a cell viability assay to compare the activity of the analogs with that of our hit compound. Several analogs showed activity comparable or superior to our hit compound at 50 uM, with at least a 95% reduction in cell viability after 48 and 96 hours.

We are currently working to identify medium-throughput in vitro functional assays that can be utilized for compound screening and profiling. Through an iterative screening, characterization, and optimization process, we hope to identify a lead-type compound to use in future preclinical studies. We are also investigating the mechanism of action downstream of the PEDF/LAMR1 interaction in prostate cancer, which will help us shed light on the therapeutic potential of LAMR1.

Support or Funding InformationCTSI Core Grant Purdue Cancer Research Center Department of Basic Medical Sciences

Citation Format: Daniel F. Edwards, Charles S. Umbaugh, Marxa L. Figueiredo. A small molecule mimic approach to the PEDF/LAMR1 interaction in prostate 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 LB-267.
Abstract LB-277: A small molecule compound targets mutant Ras driven cancers via changes in mitochondrial morphology and mTOR-dependent execution
Authors: Foo Jonathan C. , Iskandar Kartini B. , Pervaiz Shazib
Published: August 2018

In a recent report, we presented evidence that a small molecule compound selectively induces autophagy-associated execution of mutant RAS driven cancer cells via Akt-dependent mitochondrial ROS production (Iskandar, K. et al. Antiox. Redox Sig., 2016). During our efforts to explore the underlying mechanism of RAS dependent execution, we unraveled a novel mechanism of action involving changes in proteins responsible for maintaining mitochondrial morphology, Drp-1 and Opa-1. Exposure of cells to the small molecule, C1, results in specific phosphorylation of Drp-1 (serine 616) associated with mitochondrial fission as well as cleavage of the fusion associated protein Opa-1. Gene knockdown of KRAS significantly abrogated drug-induced phosphorylation of Drp-1 and rescued mitochondrial morphology. Interestingly, siKRAS also resulted in the complete inhibition of mitophagy induced upon exposure to the small molecule compound; mitophagy in this model is driven by the activation of Drp-1. We also provide evidence that KRAS is recruited to the mitochondria, upstream of Drp-1 activation and mitophagy induction in response to drug treatment. Furthermore, as Akt activation was linked to an increase in ROS production and knockout of Akt1/2 salvaged cells from the death inducing activity of C1, we studied the mechanism of Akt activation in this model. We present evidence that Akt activation might be downstream of Torin-sensitive but not Rapamycin-sensitive mTOR activation. Furthermore, a priori treatment with Torin completely blocked the effect of C1 on tumor colony forming ability. These data provide an interesting insight into the molecular mechanism(s) of a small molecule compound that triggers RAS dependent execution with potential therapeutic implications.

Citation Format: Jonathan C. Foo, Kartini B. Iskandar, Shazib Pervaiz. A small molecule compound targets mutant Ras driven cancers via changes in mitochondrial morphology and mTOR-dependent execution [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-277.
Abstract LB-301: Inhibition of the co-inhibitory receptor KLRG1 reduces murine 4T1 breast cancer metastasis and MC38 colon cancer primary tumor growth and mortality
Authors: Greenberg Steven A. , Gulla Stefano V. , Thompson Evan
Published: August 2018

Introduction

Targeting of lymphocyte co-inhibitory receptors, such as CTLA-4, PD-1, Lag-3, and Tim-3, has gained intense interest for treatment of cancer. KLRG1 is also a lymphocyte co-inhibitory receptor, expressed predominantly on effector memory CD8+ T cells and NK cells, whose ligands E- and N-cadherin are differentially expressed during epithelial-mesenchymal transition. Targeting of KLRG1 in murine cancer models has not previously been published.

Methods

We constructed an anti-mouse KLRG1 antibody that neutralized the interaction of KLRG1 with its ligands. Anti-KLRG1 antibody was administered as a monotherapy in a murine metastatic tumor model (4T1 murine breast cancer) and as combination therapy with anti-PD-1 (clone RMP1-14) in a murine primary tumor growth model (MC38 murine colon cancer).

Results

In the 4T1 murine breast cancer model, anti-KLRG1 antibody reduced lung metastases compared to control antibody as measured by mean lung weights (0.28 g vs. 0.47 g; p=0.04) and nodule count (10.7 vs. 30.1; p=0.002). In the MC38 model, primary tumor growth was inhibited by anti-KLRG1 + anti-PD-1 antibody greater than anti-KLRG1 antibody or anti-PD-1 antibody or control antibody (day 13 tumor volume 582 vs. 1259 vs. 1279 vs. 1461 mm3, respectively). Combination therapy anti-KLRG1 + anti-PD-1 produced synergistic benefit significantly greater than that of anti-PD-1 alone for tumor volume (p=0.01) and survival (p=0.02; day 18 survival 60% of mice alive treated with combination therapy compared to 0% alive treated with anti-PD-1 alone). Ex vivo KLRG1 blockade with anti-human KLRG1 antibodies resulted in human CD8+ T cell proliferation and proinflammatory cytokine secretion.

Conclusions

Anti-KLRG1 neutralizing antibody demonstrates efficacy in inhibiting metastases in the murine 4T1 breast cancer model and reducing primary tumor volume and improving survival as synergistic combination therapy with anti-PD-1 in the murine MC38 colon cancer model. Anti-KLRG1 blockade with anti-human KLRG1 antibodies results in activation of CD8+ T cells. These data suggest that anti-KLRG1 treatment is a promising new approach for cancer immunotherapy.

Citation Format: Steven A. Greenberg, Stefano V. Gulla, Evan Thompson. Inhibition of the co-inhibitory receptor KLRG1 reduces murine 4T1 breast cancer metastasis and MC38 colon cancer primary tumor growth and mortality [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-301.
Abstract LB-310: hnRNPM drives cell-state specific alternative splicing during EMT through combinatorial regulation with other RNA binding proteins
Authors: Harvey Samuel E. , Cheng Chonghui
Published: August 2018

The epithelial-mesenchymal transition (EMT) is a fundamental developmental program that is abnormally activated in cancer cells, resulting in therapeutic resistance and metastasis. Dramatic changes in alternative splicing occur during EMT, however the master regulators of this critical regulatory layer are poorly understood. We previously identified the ubiquitously expressed RNA binding protein hnRNPM as a causal driver of EMT and breast cancer metastasis whereby hnRNPM drives alternative exon skipping of the cancer stem cell marker CD44 in a mesenchymal-cell-state restricted manner. However, the scope of hnRNPM-mediated regulation of the EMT post-transcriptional landscape and the mechanisms by which hnRNPM functions in a cell-state specific fashion remain uncertain. By integrating breast epithelial and mesenchymal hnRNPM-depletion RNA-sequencing datasets coupled with individual nucleotide crosslinking and immunoprecipitation of hnRNPM, we identified cell-state specific hnRNPM target RNAs undergoing alternative splicing. hnRNPM cell-state specific targets enrich for distinct gene ontology terms where epithelial targets are enriched in genes critical for the cell cycle while mesenchymal targets cluster in pathways associated with cell migration and EMT. Strikingly, we found hnRNPM regulates splicing to oppose EMT in the epithelial state but then promotes EMT in the mesenchymal state. This unexpected regulatory switch where hnRNPM maintains the cell-cycle in epithelial cells while driving cell migration and metastasis in mesenchymal cells suggests a dual role for hnRNPM in sustaining epithelial and mesenchymal-type breast cancers. Motif analysis and regulon overlap of cell-state specific hnRNPM targets identify ESRP1 and other RNA binding proteins as putative mediators of hnRNPM cell-state specific activity during EMT. Together, this study extends our functional understanding of how hnRNPM regulates the EMT post-transcriptional program and functions in different subtypes of breast cancer.

Citation Format: Samuel E. Harvey, Chonghui Cheng. hnRNPM drives cell-state specific alternative splicing during EMT through combinatorial regulation with other RNA binding proteins [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-310.
Abstract LB-317: Anti-invasive effects of saracatinib in preclinical models of luminal bladder cancer
Authors: Wehrenberg Bryan , Neal David , Ochoa Andrea , Choi Woonyoung , McConkey David
Published: August 2018

Bladder cancers (BC) form biologically and clinically distinct luminal and basal subtypes. In both subtypes, identifying treatments to prevent progression from non-muscle invasive to muscle invasive disease is a major clinical priority. Anti-invasive agents, such as the SRC and SRC-Family Kinase inhibitor, saracatinib, may benefit high risk non-muscle invasive BC patients. We hypothesized that SRC inhibition limits invasion in bladder tumor models. We examined SRC mRNA expression in the luminal and basal subtypes of BC using publicly available The Cancer Genome Atlas (TCGA) data. Using RNA-Seq expression data, we classified 30 human BC cell lines as luminal or basal and compared SRC expression between the subtypes. We then studied the effect of saracatinib in luminal and basal BC models. Proliferation was measured by MTT assay and invasion was measured using transwell assays. Transwells were either uncoated (modeling migration), matrigel coated (modeling basement membrane invasion) or collagen-1 coated (modeling muscle wall invasion). Luminal TCGA bladder tumors showed significantly enrichments in SRC mRNA expression (p<0.001). SRC expression was significantly higher in luminal than basal cell lines (p<0.05). Saracatinib had limited anti-proliferative activity in both luminal and basal models. All luminal models showed significantly decreased migration and collagen 1 invasion (p<0.05). Of the subset of luminal cell lines that invade matrigel, two thirds had significantly decreased invasion (p<0.05). Only one basal cell line exhibited significantly decreased invasion or migration (p<0.05). Invasion and migration in other basal models were not significantly altered or, in several case, were significantly increased (p<0.05), by saracatinib. Enrichment of SRC expression in luminal tumors and significant reductions in luminal cell line invasion after saracatinib treatment suggest SRC promotes invasion in luminal BC. The increase in basal cell line invasion, observed in a subset of these models, emphasizes the importance of considering subtype in studying the biology of BC. Though further validation in 3D culture and animal models is necessary, these results suggest saracatinib, and other SRC-Family Kinase inhibitors, could serve as effective anti-progression agents in luminal BC.

Citation Format: Bryan Wehrenberg, David Neal, Andrea Ochoa, Woonyoung Choi, David McConkey. Anti-invasive effects of saracatinib in preclinical models of luminal bladder 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 LB-317.
Abstract LB-318: Automated monitoring and analysis of kinetic live cell 3D spheroid-based tumor invasion within a hydrogel matrix
Authors: Larson Brad
Published: August 2018

Metastasis is the main cause of death in cancer patients and one of the most complex biological processes in human diseases. The development of therapies designed to forestall the metastatic activity of tumors has been met with multiple challenges. The first is the initial focus on single target remedies. As many types of cancers develop multiple mutations during tumor progression, individual cancers are often little affected by this type of drug. The advancement of novel methods that allow for the discernment of the effect a potential therapy has on the invasive phenotype of a particular type of cancer has proven invaluable to circumventing these early failures. A second hurdle is the choice of an appropriate cell model. Tumors in vivo exist as a three-dimensional (3D) mass of multiple cell types, including cancer and stromal cells. Therefore, incorporating a 3D spheroid-type cellular structure that includes co-cultured cell types forming a tumoroid, provides a more predictive model than the use of individual cancer cells cultured on the bottom of a well in traditional two-dimensional (2D) format. A third impediment is the inclusion of proper incubation time. Traditionally in vitro assessments of anti-cancer drugs have included short-term incubations, sometimes limited to 48 hours. In vivo treatments, however, can consist of a multi-week regimen. Pre-clinical tests must also, then, extend a similar length of time. A final hindrance which is necessary to overcome is the proper capture and analysis of microscopic images. The ability to monitor the entire tumoroid with a degree of sensitivity across multiple z-planes as cells invade into the matrix, as well as quantify changes over time, is critical. The information presented here will demonstrate a combined procedure for the generation of 3D spheroidal tumoroid structures, creation of a suitable invasion matrix, automated kinetic image-based monitoring of tumor invasion, and cellular analysis of captured z-stacked images.

Citation Format: Brad Larson. Automated monitoring and analysis of kinetic live cell 3D spheroid-based tumor invasion within a hydrogel matrix [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-318.
Abstract LB-342: Targeted gene control with bifunctional molecules to harness endogenous chromatin-modifying activity
Authors: Chiarella Anna M. , Butler Kyle V. , Jin Jian , Hathaway Nathaniel A.
Published: August 2018

Epigenetic pathways are commonly found disrupted in many human diseases including cancer, yet much remains unknown about the mechanisms by which dysregulation of chromatin regulatory pathways leads to disease pathology. To investigate and control these complex interactions in live cells, we developed a novel system that will unveil the underlying mechanisms of proteins responsible for modulating chromatin states using a gene-specific manipulation strategy. To explore how dynamic changes in acetylation levels impact chromatin structure we generated an endogenous reporter system at the murine Oct4 locus with a Gal4 DNA binding array upstream of an EGFP reporter allele. In our system, a FKBP protein fused to a Gal4 DNA-binding-domain serves as a protein anchor to the DNA binding array. Next, we synthesized novel cell-permeable, bifunctional molecules that include FK506 (which binds to FKBP) linked to a component that selectively binds to a histone tail chromatin-modifying enzyme. We characterized the effects of the Chemical Epigenetic Modifiers (CEM)s using flow cytometry, high-content microscopy and chromatin immunoprecipitation. We show that our lead repressive CEM can repress GFP expression by 50%. Next, we have made our system more modular by creating a deactivated Cas9 (dCas9)-FKBP fusion protein. The FKBP portion allows us to recruit our CEMs to any region of the genome to which we design a guide RNA. To study the addition of histone acetylation we utilized our new activating, HAT-binding CEMs and designed our dCas9-FKBP to target low-expression reporters. Our lead activating CEM increases expression over 20-fold. We are now using our activating CEM system to target tumor suppressor genes in hard to treat cancers. To show proof-of-principle, we have targeted the tumor suppressor p53 in a colon cancer cell line. We hypothesize that our activating CEM platform will activate the repressed P53 allele leading to slower tumor cell proliferation and apoptosis. This work represents a novel therapeutic strategy that is capable of modulating gene expression in a reversible and dose-dependent manner.

Citation Format: Anna M. Chiarella, Kyle V. Butler, Jian Jin, Nathaniel A. Hathaway. Targeted gene control with bifunctional molecules to harness endogenous chromatin-modifying activity [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-342.
Abstract LB-379: Targeted single-cell RNA expression profiling for cellular characterization of tumor microenvironment
Authors: Chenchik Alex , Makhanov Michael , Frangou Costa , Diehl Paul
Published: August 2018

New rapid and robust transcriptome-based methods for cellular characterization of the tumor microenvironment and biomarker discovery are required to improve prognosis and treatment of cancer and other diseases. However, challenges with current approaches for the above applications include high sample requirements, poor sensitivity, low dynamic range, and limited throughput. To address these limitations, we have developed the DriverMap™ targeted RNA expression profiling assay using a genome-wide set of 19,000 validated primer pairs that leverages the sensitivity of multiplex RT-PCR with the throughput and digital readout depth of next-generation sequencing (NGS). Starting from just 10pg (single-cell) to 100ng (10,000 cells) of total RNA is sufficient to quantify over 5 orders of magnitude variation in gene expression levels with performance similar to conventional qRT-PCR. Further, the use of gene-specific primers enables direct analysis of total RNA isolate and obviates the need for globin and rRNA depletion from whole blood samples. And, using a subset of primers empirically selected from the DriverMap™ assay, we have developed a novel single-cell targeted RNA expression (scTRex) profiling assay compatible with conventional oligo dT-molecular indexing, single- cell barcoding strategies. In this study, we present the performance of the assay to analyze the level of immune cell infiltration in tumor samples, and identify active pathways in tumor, xenograft samples and cell lines treated with small molecules. Preliminary studies demonstrate the assay's unparalleled specificity and sensitivity resulting in better detection of low abundance mRNA transcripts as well as an improved cost-effectiveness for high-throughput clinical applications.

Citation Format: Alex Chenchik, Michael Makhanov, Costa Frangou, Paul Diehl. Targeted single-cell RNA expression profiling for cellular characterization of tumor microenvironment [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-379.
Abstract LB-387: In vivo study on the pathological role of microRNA 155 in liver malignancy
Authors: Lee Tae Jin , Yoo Ji Young , Kaur Balveen , Croce Carlo
Published: August 2018

Growing body of evidence proposes that causative factor for liver damage, such as viral infection, inflammation, fatty liver and genotoxin, induces over-expression of microRNA-155 (miR-155), and increases the chance to develop hepatocellular carcinoma (HCC), where miR-155 is also found to be highly over-expressed. To understand the underlying mechanism how over-expression of miR-155 in liver induces pathologic changes linking early liver damage to malignant HCC development, we have generated conditional transgenic and knockout mice for hepatocyte-specific over-expression or deletion of miR-155 using Cre-LoxP technology. Although the miR-155 over-expressing Tg mice did not develop spontaneous HCC, they showed early inflammation in liver with elevated level of pro-inflammatory cytokines in both liver and serum through Caspase-I activation. Postnatal insulting by genotoxin, Diethylnitrosamine (DEN), has dramatically increased incidents of HCC in miR-155 Tg mice (82%) compared to wildtype mice (21%) by 9 months. Microarray analysis on whole mouse liver transcriptome has revealed that 294 genes were significantly up-regulated in the Tg mice while 147 genes were significantly down-regulated. Further pathway analysis showed that those affected genes mainly involve in acute-phase response, inflammatory response, fatty acid metabolic process, and cholesterol metabolic process, which coincides with our phenotypic observation. In addition, it was found that high incidence of HCC by DEN insult is consequence of impaired DNA damage repair and apoptosis pathways through downregulation of several genes including Foxo3a, Sirt1, C/EBP-beta and Smac by miR-155. Our in vivo study provides first insight of dysregulation of single microRNA can set forth liver damage to malignant HCC, which makes miR-155 a promising therapeutic target not only for HCC but also many type of liver damage-related liver diseases.

Citation Format: Tae Jin Lee, Ji Young Yoo, Balveen Kaur, Carlo Croce. In vivo study on the pathological role of microRNA 155 in liver malignancy [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-387.
Abstract LB-389: miR133a-3p sensitizes breast cancer cells by targeting GSTP1
Authors: Chang Minsun , Liu Xiyuan , Park Eun Young
Published: August 2018

Breast cancer is a main threat for women's health and mammary carcinogenesis is attributed to estrogen receptor α (ERα)-mediated signaling pathways. Tamoxifen is one of the most effective ERα-targeting antiestrogen therapies to treat breast cancer. However, tamoxifen resistance remains a major hurdle in the long-term management of breast cancer. Glutathione S-transferase P1-1 (GSTP1) is one of the major non-hepatic GST family and plays important role in detoxification. Our previous study has shown that GSTP1 is a modulator for ERα signaling in tamoxifen-resistant MCF7 breast cancer cells (LCC3) and other studies have proposed that GSTP1 is one of biomarkers for the diagnosis of breast cancer risk and drug resistance. In the present study, a microRNA (miR) 133a-3p is identified as a functional modulator for GSTP1 expression and cell proliferation in LCC3 cells. We have found that level of miR133a-3p was much lower and the GSTP1 expression at both mRNA and protein was higher in LCC3 cells compared to MCF7 cells. Treatment of miR133a-3p mimics decreased the levels of GSTP1 in LCC3 cells. Finally, the miR133a-3p mimics resensitized the LCC3 cells against tamoxifen-induced cell death. Our data demonstrated that GSTP1 is the target of miR133a-3p in MCF7-derived breast cancer cells and miR133a-3p may play a critical role to overcome tamoxifen resistance in breast cancer chemotherapy.

Citation Format: Minsun Chang, Xiyuan Liu, Eun Young Park. miR133a-3p sensitizes breast cancer cells by targeting GSTP1 [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-389.
Abstract LB-399: Aspirin reduces doxorubicin-induced senescence and early-aging in mice
Authors: Feng Mingxiao , Shim Minsub
Published: August 2018

Survivors of childhood cancers are often associated with the adverse late effects of earlier cancer treatments, including hearing loss, early menopause, osteoporosis, hypoplasia, fatigue, and infertility. While an accumulating body of evidence supports the hypothesis that cancer treatment is associated with accelerated aging, the mechanisms that lead to a functional decline or frailty remain elusive. Expression of cyclooxygenase-2 (COX2), a key enzyme in prostaglandin biosynthesis, is known to be increased in the tissues of aged humans and mice. We have previously found that transgenic expression of COX2 causes premature aging phenotypes in mice. Since it is well-known that COX2 expression is highly induced by various chemotherapeutic agents, we further investigated the possible link between COX2 and the late effects of chemotherapy. Treatment of juvenile mice with doxorubicin (DOX), an anthracycline-based chemotherapeutic agent, resulted in increased cellular senescence and premature aging in adult mice. Interestingly, tissue expression of COX2 persisted even at 11 weeks after cessation of DOX treatment. In addition, aspirin, a classical non-steroidal anti-inflammatory drug (NSAID), alleviated cellular senescence and early aging phenotypes in DOX-treated mice. Moreover, NSAIDs, either a selective or non-selective COX2 inhibitors, reduced the viability of senescent cells and down-regulated the levels of Bcl-xL and LC3b. Our results suggest that chemotherapy-induced COX2 may play an important role in the late effects of chemotherapy by inducing cellular senescence and further aging.

Citation Format: Mingxiao Feng, Minsub Shim. Aspirin reduces doxorubicin-induced senescence and early-aging in mice [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-399.
Abstract PL01-02: Immune checkpoint therapy: From CTLA-4 to PD-1/PD-L1 and beyond
Authors: Sharma Padmanee
Published: August 2018

Immune checkpoint therapies, including anti-CTLA-4, anti-PD-1, and anti-PD-L1, have led to significant clinical responses in cancer patients. However, there are still substantial numbers of patients who do not respond to anti-CTLA-4 or anti-PD-1/PD-L1. We and others have demonstrated that treatment of patients with immune checkpoint therapies impacts immune responses to enhance effector T-cell responses but also leads to increased expression of compensatory pathways or development of adaptive resistance mechanisms that act to abrogate antitumor immune responses. Rational combination strategies to address these compensatory pathways and/or adaptive resistance mechanisms, including those that permit blockade of multiple T-cell inhibitory pathways or blockade of inhibitory pathways plus targeting of co-stimulatory pathways or intervention with agents, such as epigenetic agents, to promote differentiation of effector T cells and/or M1 macrophages, are at the forefront of preclinical and clinical studies as the field of immune checkpoint therapy aims to provide benefit to even more patients. Combination therapies with anti-CTLA-4 and anti-PD-1 have already shown improved patient benefit. The next promising combinations include those with ICOS, CD47, VISTA, oncolytic viruses, and EZH2-inhibitors, to name a few. Preclinical and clinical data regarding these targets will be discussed in greater detail.

Citation Format: Padmanee Sharma. Immune checkpoint therapy: From CTLA-4 to PD-1/PD-L1 and beyond [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 PL01-02.
Abstract SY01-02: Blockade of estrogen signaling boosts antitumor immunity by dwindling cancer-promoting myelopoiesis
Authors: Svoronos Nikolaos , Perales-Puchalt Alfredo , Conejo-Garcia Jose R.
Published: August 2018

Although the role of estrogen signaling in the progression of breast tumors and a subset of ovarian cancer patients has been underscored by the clinical use of ER antagonists, how estrogens impact the orchestration and maintenance of protective antitumor immunity remains elusive. Here we show that estrogen signaling accelerates the progression of different estrogen-insensitive tumor models by contributing to tumor-promoting, expanded myelopoiesis. This results in increased mobilization of myeloid-derived suppressor cells (MDSCs) and also the augmentation of their intrinsic immunosuppressive activity on a per cell basis, in vivo in the bone marrow of tumor-bearing hosts. Accordingly, estrogens had a profound effect on T cell-dependent antitumor immunity and tumor-promoting inflammation, independently of the sensitivity of tumor cells to estrogen signaling. Differences in tumor growth in the presence of estrogen-insensitive tumor cells are dependent on blunted antitumor immunity and, correspondingly, disappear in immunodeficient hosts and also upon MDSC depletion. Mechanistically, estrogen receptor alpha activates the STAT3 pathway in human and mouse bone marrow myeloid precursors by enhancing JAK2 and SRC activity. Consequently, fulvestrant had significant effects in delaying the progression of estrogen-insensitive tumors, providing a rationale for blocking estrogen signals to boost the effectiveness of anticancer immunotherapies, which is currently being tested at our institution in breast cancer patients. Our data therefore provide novel mechanistic insight into how enhanced estrogenic activity contributes to malignant progression in established tumors by driving pathologic, tumor-promoting myelopoiesis. Our work suggests that new antiestrogen drugs that have no agonistic effects (different from tamoxifen) could have benefits to boost protective immunity in a wide range of cancers, while augmented estrogenic activity could contribute to tumor initiation and/or malignant progression.

Citation Format: Nikolaos Svoronos, Alfredo Perales-Puchalt, Jose R. Conejo-Garcia. Blockade of estrogen signaling boosts antitumor immunity by dwindling cancer-promoting myelopoiesis [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 SY01-02.
Abstract SY05-02: Polycomb dysregulation by oncohistones
Authors: Lewis Peter W.
Published: August 2018

Covalent modifications to both the DNA and the histone proteins allow chromatin to act as a dynamic information hub that integrates diverse biochemical stimuli to regulate genomic DNA access to the transcription machinery and ultimately establish and maintain cellular phenotypes. Moreover, there is increasing appreciation that chromatin alterations per se, including DNA and histone modifications, are involved in the pathogenesis of cancer. Nowhere is this better supported than with the groundbreaking discoveries of high-frequency, somatic mutations in histones that are drivers of oncogenesis. These mutations (collectively called "oncohistones") cause amino acid substitutions that localize to conserved residues in the N-terminal tail of histone H3 and all seem to be linked, either directly or indirectly, to disruption of normal levels and distribution of histone H3 methylation and thus genomic regulation. Specifically, oncohistones directly or indirectly promote aberrant genome-wide distribution of lysine 27 methylation on histone H3. H3K27 methylation, catalyzed by the Polycomb Repressive Complex 2 (PRC2), is mechanistically linked to establishment and maintenance of gene repression. We are currently using a combination of biochemical and genomic approaches to investigate how oncohistone-driven changes in histone H3 K27 methylation lead to altered chromatin states that profoundly influence gene expression patterns. I will discuss some of our recent mechanistic and functional work on various oncohistone mutations.

Citation Format: Peter W. Lewis. Polycomb dysregulation by oncohistones [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 SY05-02.
Abstract SY29-03: The impact of aerobic exercise on breast cancer progression
Authors: Nelson Erik R.
Published: August 2018

In 1924, Otto Warburg first postulated that cancer was caused by altered metabolism, specifically the reliance of cancer cells on glycolysis. Since then, this altered metabolism has been recognized as a "hallmark of cancer," with numerous studies supporting this. It is now clear that pathologies resulting in perturbed homeostasis at the level of the organism, such as obesity, diabetes, and hypercholesterolemia, are also associated with tumor progression. Since aerobic exercise is known to alter systemic homeostasis, we reasoned that it may also impact tumor progression. In this regard, emerging epidemiologic evidence indicates an inverse correlation between exercise and the onset of many forms of cancer, including breast cancer. Intriguingly, several studies have found that self-reported physical activity is associated with decreased recurrence. We have now directly tested the impact of exercise on the progression of breast cancer, using several murine models of mammary cancer, finding that exercise significantly reduces tumor growth and metastasis. Subsequent work has been focused on delineating the molecular mechanisms by which exercise hinders the progression of breast cancer. We will discuss these results and present our current understanding of how exercise influences tumor pathophysiology. Collectively, our work suggests that aerobic exercise may offer an effective complementary adjunct therapy with current standard of care.

Citation Format: Erik R. Nelson. The impact of aerobic exercise on breast cancer progression [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 SY29-03.
Abstract 17: In situ immune expression signatures before and after ipilimumab therapy for relapsed acute myeloid leukemia after allogeneic stem cell transplantation
Authors: Bachireddy Pavan , Davids Matthew S. , Rooney Michael S. , Bowden Michaela , Zhou Chensheng W. , Rodig Scott J. , Ho Vincent , Antin Joseph , Koreth John , Alyea Edwin , Soiffer Robert J. , Wu Catherine J.
Published: August 2018

Immune evasion may facilitate hematologic relapse after allogeneic hematopoietic stem cell transplantation (allo-SCT). We recently demonstrated that CTLA4 blockade with ipilimumab reinvigorates a graft-versus-leukemia effect to induce complete remissions of acute myeloid leukemia (AML) relapsing after allo-SCT. Here, we hypothesized that immune subpopulation dynamics and activation states inferred from in situ gene expression changes within the leukemic microenvironment are informative of clinical outcome. We undertook an in situ transcriptomic characterization of paired, pre/post ipilimumab leukemic biopsies from five samples with relapsed, extramedullary AML. We performed a response-to-treatment expression analysis for each patient and found three immune patterns corresponding to three clinical response patterns following ipilimumab (durable response, relapse, and primary resistance). Durable responses were characterized by a diverse infiltration of activated cytotoxic T lymphocytes, B cells, and macrophages. In contrast, primary resistance was associated with both marked infiltration of CD8 T cells deficient in T-cell receptor signaling, activation, or cytolytic activity and absent infiltration of other immune effectors. Interestingly, the sample with transient response and eventual relapse demonstrated pre- and post-treatment immunologically “inflamed” states that were strongly downregulated during clinical relapse. In situ gene expression analyses of leukemic biopsies before and after ipilimumab therapy suggest that specific patterns of immune population dynamics and activation states underlie diverse clinical outcomes.

Citation Format: Pavan Bachireddy, Matthew S. Davids, Michael S. Rooney, Michaela Bowden, Chensheng W. Zhou, Scott J. Rodig, Vincent Ho, Joseph Antin, John Koreth, Edwin Alyea, Robert J. Soiffer, Catherine J. Wu. In situ immune expression signatures before and after ipilimumab therapy for relapsed acute myeloid leukemia after allogeneic stem cell transplantation [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 17.
Abstract 50: Small molecule Ring1B-Bmi1 inhibitor attenuates PRC1 E3 ligase activity and targets leukemia stem cells self-renewal
Authors: Shukla Shirish , Gray Felicia , Ying Weijiang , Cho Hyoje , Zhao Qingjie , Miao Hongzhi , Miao Hongzhi , Purohit Trupta , Guzman Monica , Grembecka Jolanta , Cierpicki Tomasz
Published: August 2018

Polycomb group proteins, Ring1B and Bmi1 constitute catalytic component of Poly-comb Repressive Complex 1(PRC1) and execute gene silencing through histone H2A lysine119 ubiquitination (H2AK119ub). Bmi1 is overexpressed in a wide range of human cancers and has been implicated in regulation of leukemic stem cells (LSCs) self-renewal capacity. LSCs are refractory to the conventional therapies and eventually lead to the disease relapse. Small-molecule inhibitors of the Ring1B-Bmi1 E3 ligase activity have not been reported to date, but are highly desired as potential therapeutic agents to target LSCs. In the present study, employing fragment-based screening and extensive medicinal chemistry optimization, we developed WY332 that binds to Ring1B-Bmi1 with low micromolar affinity. Extensive characterization of the WY332 demonstrated selective reduction in Ring1B-Bmi1 mediated H2AK119ub levels in vitro and in leukemic cells whereas structurally similar and less potent compound displayed similar effect at much higher concentrations. Treatment of model cell lines, TEX and M9:ENL1, enriched in leukemia initiating cells show that the reduction in H2AK119ub levels is associated with induction of cellular differentiation and altered colony-forming potential. Further, gene expression analysis of TEX cells treated with WY332 indicated reprogramming of CD34+ cells and revealed significant increase in expression of genes suppressed in LSCs. In addition, WY332 treatment led to a marked increase in CD11b expression and significantly decreased CD34 expression in TEX cells. Evaluation of WY332 in patients' derived primary AML cells further revealed reprogramming of gene expression profile and phenotypic markers associated with LSCs self-renewal property. Overall, these compounds represent the novel small-molecule inhibitors of Ring1B-Bmi1 which inhibit E3 ubiquitin ligase activity and impair leukemic stem cell self-renewal capacity.

Citation Format: Shirish Shukla, Felicia Gray, Weijiang Ying, Hyoje Cho, Qingjie Zhao, Hongzhi Miao, Hongzhi Miao, Trupta Purohit, Monica Guzman, Jolanta Grembecka, Tomasz Cierpicki. Small molecule Ring1B-Bmi1 inhibitor attenuates PRC1 E3 ligase activity and targets leukemia stem cells self-renewal [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 50.