bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5491: Blocking acyl-CoAs synthesis inhibits prostate cancer progression
Authors: Cai Houjian , Ma Yongjie
Published: August 2018

Fatty acid metabolism is essential for the biogenesis of cellular components and ATP production to sustain proliferation of cancer cells. Bioconversion of exogenous or de novo synthesized fatty acids to their corresponding fatty acyl-CoAs, which is required for the fatty acids to participate in metabolic processes, is catalyzed by long chain fatty acyl-CoA synthetases (ACSLs). However, the influence of individual ACSL isoforms on the progression of prostate cancer remains unknown. The goal of this study is to analyze how ACSLs regulates the biosynthesis of acyl-CoAs, thereby prostate cancer progression. In this study, lentivirus carrying shRNA of ACSL1 was constructed and produced in house. Oxygen Consumption Rate (OCR) and Extracellular Acidification Rate (ECAR) were measured by Seahorse. The amount of protein and acyl-CoAs was analyzed by immunoblotting and LC-MS/MS, respectively. Additionally, the amount of triglyceride and neutral lipid were measured by gas Chromatography and Oil red O staining. TCGA database was also used for analysis of ACSL1 expression levels in different stages of prostate cancer. Finally, inhibition of cell proliferation, migration, invasion assays and cell cycle analysis were examined in numerous cancer cells. Prostate xenograft tumor models were applied for in vivo studies. Prostate tumor tissue array was utilized for the analysis of ACSL1 expression. Based on the systematic analysis on the correlation of ACSL expression levels and the amount of intracellular acyl-CoAs, we demonstrate that expression levels of ACSL1 were significantly associated with the levels of a variety of acyl-CoAs, and were elevated in human prostate tumors. ACSL1 increased the biosynthesis of fatty acyl-CoAs including C16:0-, C18:0-, C18:1- and C18:2-CoA, triglycerides and lipid accumulation in cancer cells. In addition, ACSL1 modulated mitochondrial respiration through regulation of carnitine palmitoyltransferase 1A (CPT1A) activity. Knockdown of ACSL1 expression inhibited the cell cycle, and suppressed the proliferation and migration of prostate cancer cells in vitro, and growth of prostate xenograft tumors in vivo. Our study demonstrates ACSL1 plays an important role in prostate tumor progression. Our results provide a therapeutic strategy of targeting fatty acid metabolism for the treatment of prostate cancer.

Citation Format: Houjian Cai, Yongjie Ma. Blocking acyl-CoAs synthesis inhibits prostate 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 5491.
Abstract 5497: Effective combination therapy for breast cancer targeting BACH1 and mitochondrial metabolism
Authors: Lee Jiyoung , Yesilkanal Ali , Frankenberger Casey , Elbaz Mohamad , Rabe Daniel , Yan Jielin , Rustandy Felicia , Hart Peter , Kang Christie , Grossman Elizabeth , Locasale Jason , Nomura Daniel , Bonini Marcelo , Rosner Marsha
Published: August 2018

Oxidative phosphorylation is an attractive target for cancer therapy. Reprogramming metabolic pathways by promoting oxidative phosphorylation could improve the ability of metabolic inhibitors to suppress cancers with limited treatment options like triple negative breast cancer (TNBC). Here we show that BACH1, a heme-binding transcription factor whose expression is enriched in patients with TNBC, inhibits oxidative phosphorylation through direct transcriptional regulation of electron transport chain (ETC) gene expression. Treatment of cells with hemin, which induces BACH1 degradation, mimics BACH1 depletion with shRNA. Pretreatment of TNBC tumors with BACH1 shRNA or hemin overcame resistance to metformin, an anti-diabetic drug, and abolished the growth of both cell line and patient-derived tumor xenografts. BACH1 gene expression inversely correlated with ETC gene expression in breast cancer patients as well as other tumor types, highlighting the clinical relevance. This study demonstrates that oxidative phosphorylation represents an Achilles heel that can be exploited through targeting BACH1 to sensitize breast cancer and potentially other tumor tissues to mitochondrial inhibitors.

Citation Format: Jiyoung Lee, Ali Yesilkanal, Casey Frankenberger, Mohamad Elbaz, Daniel Rabe, Jielin Yan, Felicia Rustandy, Peter Hart, Christie Kang, Elizabeth Grossman, Jason Locasale, Daniel Nomura, Marcelo Bonini, Marsha Rosner. Effective combination therapy for breast cancer targeting BACH1 and mitochondrial 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 5497.
Abstract 55: Intrinsic molecular characteristics of bone marrow-disseminated tumor cells
Authors: Maeshiro Manabu , Shinriki Satoru , Nakamura Takuya , Jono Hirofumi , Nakayama Hideki , Ando Yukio , Matsui Hirotaka
Published: August 2018

Dormant or slow-cycling disseminated tumor cells (DTC) in bone marrow (BM) are known to persist in patients with various types of cancer including head and neck squamous cell carcinoma (HNSCC). BM-DTC has been thought to have possible metastatic stem cell traits although functional and clonal analysis of BM-DTC remain elusive. Recently, we reported that the intrinsic TGF-β2-triggered SDF-1-CXCR4 signaling axis was crucial for drug resistance dependent on a slow-cycling state in BM-DTC but not in lung metastatic cells. This study aimed to elucidate intrinsic molecular characteristics in BM-DTC. We used the human HNSCC cell line HEp3-originated sublines [i.e. parental line (P-HEp3), BM-DTC-derived (BM-HEp3), and lung metastases-derived sublines (Lu-HEp3)]. Our transcriptome analyses for these sublines revealed that slow-cycling and drug-resistant BM-HEp3 cells had unique gene expression signatures. In addition, our investigation for phosphorylation of 39 kinases associated with tumor progression showed enhanced activation of only Src in BM-HEp3 compared with P- and Lu-HEp3. Importantly, Src inhibition by dasatinib in these sublines led to a remarkable reduction in cell viability only in BM-HEp3. These data suggest that intrinsic molecular characteristics of BM-DTC are distinct from primary and lung metastatic tumor cells. Src activation may be important for survival of dormant or slow-cycling BM-DTC. Further studies should contribute to better understanding of biology of minimal residual disease in BM and metastatic initiation.

Citation Format: Manabu Maeshiro, Satoru Shinriki, Takuya Nakamura, Hirofumi Jono, Hideki Nakayama, Yukio Ando, Hirotaka Matsui. Intrinsic molecular characteristics of bone marrow-disseminated tumor cells [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 55.
Abstract 555: Loss of function Cbl-c mutations in solid tumors
Authors: Daniels Silvano R. , Kales Stephen C. , Liyasova Mariya , Nau Marion M. , Ryan Phil E. , Green Jeffrey E. , Lipkowitz Stanley
Published: August 2018

Receptor Tyrosine Kinase (RTK) signaling, which is essential for cellular growth and proliferation, can lead to malignant transformation and tumorigenesis when aberrantly activated. Cbl proteins (Cbl, Cbl-b, and Cbl-c) are a conserved family of RING finger (RF) ubiquitin ligases (E3) that negatively regulate the activity of several tyrosine kinases such as the EGFR. Cbl mutations have recently been identified in 5% of human myeloid neoplasms, with a majority of mutations clustered within the RF and linker domains. Cbl-c is the most recently identified Cbl protein and is exclusively expressed in epithelial cells. We recently identified a novel cDNA isolated from a mouse mammary tumor in the C3(1) Large T Antigen transgenic mouse model. This mutant cDNA encodes a protein that has a deletion in the RF domain of Cbl-c, thereby resembling known Cbl family mutations associated with myeloid neoplasias. Genomic analyses of both parental and transgenic lines show no evidence of germline mutation, suggesting that this mutation is most likely somatic. The mutant Cbl-c protein enhances transformation of NIH 3T3 cells when co-transfected with SV40 Large T Antigen. In overexpression studies, this mutant Cbl-c fails to mediate ubiquitination of activated EGFR and acts in a dominant negative manner to prevent ubiquitination of activated EGFR by wildtype Cbl proteins. Datamining also reveals Cbl-c mutations associated with human solid tumors. Cell-based analyses demonstrate a similar loss of E3 function in some of these human mutations. These data collectively suggest that, like Cbl mutations in myeloid neoplasms, loss of function Cbl-c mutants may also contribute to the pathogenesis of solid tumors in murine models and in humans.

Citation Format: Silvano R. Daniels, Stephen C. Kales, Mariya Liyasova, Marion M. Nau, Phil E. Ryan, Jeffrey E. Green, Stanley Lipkowitz. Loss of function Cbl-c mutations in solid tumors [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 555.
Abstract 5570: Analytical and clinical validation of blood-based NGS panel for detection of genomic alterations in DNA repair pathways
Authors: Wang Xiaohong , Yu Jianjun
Published: August 2018

Response to DNA-damaging agents, such as PARP inhibitors (PARPi), is associate with homologous recombination deficiency (HRD). In fact, patients with advanced breast, prostate, and ovarian cancers who carry harmful mutations in BRCA1/2 have benefited greatly from olaparib, niraparib, and rucaparib as reported in multiple clinical trials. However, current available assays either require tumor biopsy which may be of insufficient quantity or unobtainable or only examine very limited genes such as BRCA1, BRCA2, and ATM from patient blood. We recently developed a blood-based NGS panel to accurately detect genomic alterations in 51 genes related to DNA damage and repair. With in-house proprietary ultra-sensitive DeepSeaTM(Deterministic, Efficient, Precise, Sensitive Algorithm) variant detection algorithm, analytical performance was rigorously assessed via serial dilutions of reference materials and also further validated by clinical plasma samples in prostate, ovarian, lung and breast cancer.

Key words: cfDNA, DNA damage repair, PARP, BRCA1, BRCA2, liquid biopsy, biomarker

Citation Format: Xiaohong Wang, Jianjun Yu. Analytical and clinical validation of blood-based NGS panel for detection of genomic alterations in DNA repair pathways [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 5570.
Abstract 5582: Use of circulating tumor DNA (ctDNA) to predict superiority of dosing schedules in early clinical development
Authors: Chmielecki Juliann , Lai Zhongwu , Potts Kristy , Garg Kavita , Li Mark , Barrett J Carl
Published: August 2018

Changes in ctDNA can be used as a surrogate molecular marker of response to determine clinical efficacy and often precede imaging changes. This analysis is valuable to early clinical trials for dose optimization as response data may not be available for patients because of the short period of time on drug. Unlike other ctDNA applications where tumor-specific single gene mutations are followed over time, inclusion of “all comers” populations in phase I trials necessitates a comprehensive assay design optimized to detect multiple ctDNA changes from diverse tumors. Therefore, we developed a highly sensitive bespoke ctDNA panel (Resolution Bioscience) suitable for monitoring applications in “all comers” solid tumor populations. The panel uses next-generation sequencing technology to interrogate mutational hotspots from 8 oncogenes as well as the complete coding sequences of 3 tumor suppressor genes. Validation studies established the mutant allele frequency (MAF) limit of detection for short variants and small insertions/deletions as 0.1%; additionally, mutant alleles detected at or above this frequency can be followed below this threshold in serial samples. The assay requires 2mL plasma and results are reported within 14 days. In silico analysis predicted detection of at least one monitorable somatic alteration from ~63% of solid tumors that shed ctDNA. To demonstrate applicability, we used this assay to analyze serial ctDNA samples from patients enrolled in dose-escalation cohorts for the Wee1 inhibitor, AZD1775 (NCT02610075). Dosing schedules were compared for the degree of ctDNA clearance after completion of the first cycle, and correlated with subsequent RECIST response data, where available. To date, 15 patients were evaluable, with more anticipated as additional cohorts accrue. Greater ctDNA decreases were observed with higher drug dose, and longer drug exposure. Together with safety and exposure data, our studies demonstrate that ctDNA dynamics can be used to inform decisions around optimal dosing schedule. This enables rapid decision making before imaging studies are available, and complements traditional measurements of target engagement.

Citation Format: Juliann Chmielecki, Zhongwu Lai, Kristy Potts, Kavita Garg, Mark Li, J Carl Barrett. Use of circulating tumor DNA (ctDNA) to predict superiority of dosing schedules in early clinical development [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 5582.
Abstract 5599: Noninvasive genomic profiling of cerebral spinal fluid in breast cancer patient with leptomeningeal disease
Authors: Oikawa Masahiro , Ramesh Naveen , Sei Emi , Bai Shanshan , Hu Min , John de Groot F. , Rshmi Murthy , O'Brien Barbara , Navin Nicholas
Published: August 2018

Leptomeningeal disease (LMD) involves the dissemination of tumor cells from the primary breast tumors into the membranes surrounding the central nervous system and spinal cords. LMD occurs in about 5% of breast cancer patients and is associated with very poor survival. The genomic evolution of LMD in breast cancer patients has remained difficult to study, in part due to technical challenges in collecting longitudinal biopsy samples from the central nervous system. Liquid biopsies of the cerebral spinal fluid (CSF) may provide a unique opportunity to profile circulating tumor DNA (ctDNA) and has not been compared directly to non-invasive monitoring of ctDNA in blood samples. Furthermore, most non-invasive ctDNA profiling methods are limited to a targeted set of genes and have not allowed unbiased whole-genome profiling. To address these limitations, we developed an unbiased method for ctDNA analysis called PEGASUS (Plasma Exome and Genome Analysis by Size-selection and Unbiased Sequencing) that enables whole-genome sequencing of copy number aberrations and somatic mutations from ctDNA. We applied PEGASUS to sequence matched blood samples and CSF from 10 breast cancer patients with LMD. Quantitation of ctDNA levels showed that ctDNA was detected in CSF samples from 9/10 patients, while blood ctDNA was detected in only 1 LMD patient with extensive metastatic disease. Whole-genome copy number profiling at 220kb resolution and mutational profiling of a 2000 cancer gene panel of the matched CSF and blood samples was performed in 10 LMD patients using PEGASUS. Our data identified aneuploid copy number aberrations and somatic mutations (range: 11-25) in the CSF of 7 patients, including mutations in known driver genes such as BRAF, RB1, TP53 and amplifications of MYC and ERBB2. In contrast the matched blood samples showed only diploid copy number profiles and no detectable somatic mutations in 9/10 LMD patients. In one patient with extensive cranial metastatic disease with matched CSF and blood ctDNA, we found a high concordance in copy number profiles (R= 0.75) and modest concordance of somatic mutations (59.5%), but also additional CNAs and mutations that were specific to the CSF. Collectively, these data show that genomic profiling of ctDNA in CSF is technically feasible for patients with LMD, and provides a major advantage over blood ctDNA which cannot be detected in mostcases.

Citation Format: Masahiro Oikawa, Naveen Ramesh, Emi Sei, Shanshan Bai, Min Hu, de Groot F. John, Murthy Rshmi, Barbara O'Brien, Nicholas Navin. Noninvasive genomic profiling of cerebral spinal fluid in breast cancer patient with leptomeningeal disease [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 5599.
Abstract 5606: Eradication of triple-negative breast cancer cells by targeting glycosylated PD-L1
Authors: Lim Seung-Oe , Li Chia-Wei , Hung Mien-Chie
Published: August 2018

EGF signaling inhibits GSK3β-β-TrCP-mediated degradation of N-linked glycosylated programmed death ligand-1 (PD-L1), resulting in PD-L1 protein destabilization and enhanced immune checkpoint blockade efficacy. Here we show that EGF also mediates PD-L1 and receptor programmed cell death protein-1 (PD-1) interaction, requiring β-1,3-N-acetylglucosaminyl transferase (B3GNT3) expression in triple-negative breast cancer cells. Downregulation of B3GNT3 enhances cytotoxic T cell-mediated anti-tumor immunity. A monoclonal antibody targeting glycosylated PD-L1 (gPD-L1) blocks PD-L1/PD-1 interaction and promotes PD-L1 internalization and degradation. In addition to immune reactivation, drug-conjugated gPD-L1 antibody induces potent cell-killing effect as well as bystander-killing effect on adjacent cancer cells without PD-L1 expression with virtually no detectable toxicities. Our work suggests targeting protein glycosylation as a potential strategy to enhance immune checkpoint therapy.

Citation Format: Seung-Oe Lim, Chia-Wei Li, Mien-Chie Hung. Eradication of triple-negative breast cancer cells by targeting glycosylated PD-L1 [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 5606.
Abstract 5611: Inhibition of IL-6 trans-signaling in HNSCC
Authors: Simons Andrean L. , Dahl Rachel A. , Espinosa-Cotton Madelyn , Rodman Samuel N. , Rose-John Stefan
Published: August 2018

Various types of cancers including head and neck squamous cell carcinomas (HNSCCs) are highly inflammatory, and the cytokine interleukin-6 (IL-6) is believed to be associated with this inflammatory phenotype. Unfortunately, global inhibition of IL-6 signaling has demonstrated little to no clinical efficacy in various types of cancers. Previous studies in the field have reported major differences between IL-6 classical signaling through the membrane bound IL-6R (mIL-6R) and IL-6 trans-signaling through the soluble IL-6R (sIL-6R), and the idea that these 2 pathways may have vastly different functions. Recent studies in models of inflammation have proposed that IL-6 classical signaling serves an anti-inflammatory/homeostatic role while IL-6 trans-signaling stimulates proinflammatory events. Therefore, IL-6 trans-signaling (and not classical signaling) may be associated with the proinflammatory phenotype observed in HNSCCs and may also be responsible for the increased tumor progression and treatment resistance frequently encountered with this disease. The goal of this work is to investigate if selective inhibition of IL-6 trans-signaling will demonstrate superior antitumor efficacy compared to global inhibition of IL-6 signaling in HNSCC cells and if selective inhibition of IL-6 trans-signaling will enhance the antitumor efficacy of chemo/radiotherapy in HNSCC cells. We observed that the HNSCC cell lines SQ20B, SCC-25, FaDu and Cal-27 all express mIL-6R and secrete IL-6, sIL-6R, and the natural inhibitor of sIL-6R signaling–soluble glycoprotein 130 (sgp130)–at varying levels. Simultaneous inhibition of IL-6 classical and trans-signaling using the IL-6R antagonist tocilizumab, and selective inhibition of IL-6 trans-signaling using the extracellular portion of gp130 fused to the Fc portion of human IgG1 (sgp130-Fc), showed no significant effects on cell survival in vitro. However, sgp130-Fc significantly suppressed SQ20B tumor growth in athymic nude mice while tocilizumab had no effect. Significant antitumor effects of sgp130-Fc were also observed in a murine SCCVII/C3H syngeneic mouse model. Cell lines treated with cisplatin and/or X-ray radiation (0-4 Gy) increased IL-6, sIL-6R and sgp130 in a dose-dependent manner and sgp130-Fc significantly increased SQ20B tumor response to chemo/radiotherapy in vivo. Altogether, this work suggests that selective inhibition of IL-6 trans-signaling using sgp130-Fc may be more effective than global IL-6 inhibition with respect to suppressing HNSCC tumor growth and warrants further study as an adjuvant to standard HNSCC therapy.

Citation Format: Andrean L. Simons, Rachel A. Dahl, Madelyn Espinosa-Cotton, Samuel N. Rodman, Stefan Rose-John. Inhibition of IL-6 trans-signaling in HNSCC [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 5611.
Abstract 5616: Rituximab chemotherapy induces a partial recovery from T-cell exhaustion in follicular lymphoma patients
Authors: Milcent Benoit , Brice Pauline , Thieblemont Catherine , Teillaud Jean-Luc , Siberil Sophie
Published: August 2018

For many years, the clinical responses observed in cancer patients treated with antitumor antibodies have been viewed only as a consequence of the recruitment and activation of innate immune cells. Several preclinical studies have indicated that anti-tumor antibodies can also induce a potent anti-tumor adaptive T-cell response capable of protecting animals from tumor challenge. Our studies have shown that CD4+ Th1 cells play a central role in the response to anti-CD20 tumor therapy by opposing Treg expansion and that CD20-specific memory T cells are responsible for anti-tumor protection observed in surviving animals subjected to tumor rechallenge. Whether an adaptive T-cell response is elicited in patients with Follicular Lymphoma (FL) receiving anti-CD20-based treatment is not known. In the present work, we analyzed peripheral T cells before and during anti-CD20-chemotherapy treatment of FL patients (R-CHOP) with high tumor burden. We first examined in ELISPOT assays the IFN-γ production by PBMC from 20 patients against human CD20-derived peptides previously selected by combining in silico and in vivo screening using transgenic human HLA-DR mice. Both FL patients before treatment and patients undergoing R-CHOP treatment exhibited peripheral T-cell responses to the selected CD20-derived peptides. However, these responses were markedly lower than those observed in healthy donors. Similar results were also obtained when T cell responses against viruses commonly infecting large numbers of individuals (CMV, EBV, influenza) were assessed, suggesting that high tumor burden FL patients exhibit an immune exhaustion of T cells. Multiparametric flow cytometry analyses suggested that their poor ability to respond to viral and CD20-derived peptides is related to the presence of an immunocompromised and exhausted blood T-cell peripheral compartment with higher percentages of TIGIT- and PD-1-expressing T cells, of peripheral Treg, and terminally differentiated CD8+ TEMRA. R-CHOP therapy induced a shift of CD4+ and CD8+ T cells toward a central memory phenotype (TCM), an additional shift of CD8+ T cells to a naive phenotype, and a decrease in the number of PD-1+ and TIGIT+ T cells, making these cells evolving toward a lesser degree of exhaustion. However, it did not restore a level of specific responses similar to those observed in healthy donors. These results support the use of anti-PD-1 and anti-TIGIT antibodies in combination with anti-CD20 in FL patients with high-tumor burden.

Citation Format: Benoit Milcent, Pauline Brice, Catherine Thieblemont, Jean-Luc Teillaud, Sophie Siberil. Rituximab chemotherapy induces a partial recovery from T-cell exhaustion in follicular lymphoma patients [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 5616.
Abstract 5643: TCRβ repertoire analysis from a prophylactic MUC1 cancer vaccine trial
Authors: Miller Michelle L. , Lohmueller Jason , McKolanis John R. , Schoen Robert , Finn Olivera J.
Published: August 2018

Mucin 1 (MUC1) is a large transmembrane glycoprotein that is overexpressed and hypoglycosylated in many adenocarcinomas, including colon cancer. In the hypoglycosylated state, the peptide core of the 20aa variable number of tandem repeats (VNTR) region is exposed, allowing it to function as an altered-self ligand for antibodies and T cells. VNTR peptides have been previously used as antigens in therapeutic cancer vaccines. A clinical trial was conducted to test immunogenicity and safety of a MUC1 100mer VNTR peptide+polyICLC adjuvant vaccine in a prophylactic setting in patients with premalignant colon adenomas who were at high risk for later developing colon cancer. In this premalignant setting, where patients were expected to have fewer immunosuppressive countermeasures usually present in patients with cancer, nearly half of the individuals generated IgG antibodies with no noted adverse effects. Because the antibody response was isotype-switched, it suggested simultaneous T cell activation. To determine whether changes in T cell clonal abundance following immunization could be detected, we sequenced and analyzed TCRβ repertoires from PBMCs of 21 antibody-responders collected before and after both primary and one-year booster vaccinations. Of the patients analyzed, we identified 8 TCRβ sequences from three patients that were significantly elevated after both priming and boosting immunizations, potentially identifying T cell clones that expanded in response to the vaccine. 16 TCRβ sequences from four individuals were significantly decreased at both time points, potentially identifying T cell clones that left circulation to participate in immune responses in secondary lymphoid organs or tissues. The timing of blood collection at two weeks post immunization may have been too late to allow us to detect all of the vaccine-expanded clones before they left circulation. In summary, we found 24 TCRβ CDR3 sequences from 7/21 vaccine responders that significantly changed in frequency after both primary and booster vaccinations. TCR sequencing studies from patients' T cells expanded in vitro with MUC1 peptide will be performed to determine if they overlap with those sequenced ex vivo.

Citation Format: Michelle L. Miller, Jason Lohmueller, John R. McKolanis, Robert Schoen, Olivera J. Finn. TCRβ repertoire analysis from a prophylactic MUC1 cancer vaccine trial [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 5643.
Abstract 567: The lysosomal transporter SLC46A3 is a potential predictive biomarker for antibody-drug conjugates bearing the non-cleavable warheads SG3376 and DM1
Authors: Kinneer Krista , Tai Yu-Tzu , Sridhar Sriram , Meekin John , Phipps Sandrina , Ruddle Ben , Fleming Ryan , Dimasi Nazzareno , Herbst Ronald , Tiberghien Arnaud , Masterson Luke , Howard Philip , Anderson Kenneth , Tice David
Published: August 2018

Antibody drug conjugates (ADCs) combine a monoclonal antibody with a potent cytotoxic drug to preferentially eliminate antigen-positive cells for the treatment of cancer. ADCs bearing non-cleavable drug-linkers such as the pyrrolobenzodiazepine (PBD) SG3376 or the maytansinoid DM1 rely upon lysosomal degradation of the antibody for release of the cytotoxic warheads, which must then escape the lysosome and bind to their intracellular targets. We sought to identify the mechanism of lysosomal transport of these membrane-insoluble warheads and have recently reported that the lysosomal transporter SLC46A3 is required for cytotoxic activity of ADCs bearing SG3376 and DM1, and that loss of SLC46A3 is a mechanism of acquired resistance to Trastuzumab-DM1 (T-DM1). Here we explore the potential translational relevance of SLC46A3. Analysis of SLC46A3 mRNA expression across several tumors showed that breast cancer cell lines and primary tumor samples have relatively high levels of SLC46A3 compared to samples derived from multiple myeloma (MM), esophageal, and upper aerodigestive tract malignancies, all of which are being targeted in clinical trials with non-cleavable DM1 ADCs. Deeper analysis indicates that levels of SLC46A3 are decreased in MM patients compared to healthy donors, and levels are further decreased in the relapsed/refractory setting compared to samples taken at diagnosis. We measured the expression of SLC46A3 in a panel of MM cell lines by RT-PCR and found that 5 of 9 (56%) had undetectable levels of SLC46A3. In vitro cytotoxicity assays demonstrate that SLC46A3-negative cells are resistant to B-cell maturation antigen (BCMA)-targeted ADCs prepared with non-cleavable DM1 and SG3376 warheads, but remain sensitive to the cleavable payload PBD SG3249 (Tesirine). Taken together, our results suggest that SLC46A3 may be a predictive response marker for ADCs bearing the non-cleavable warheads SG3376 and DM1, and this marker may be particularly useful in trials involving MM.

Citation Format: Krista Kinneer, Yu-Tzu Tai, Sriram Sridhar, John Meekin, Sandrina Phipps, Ben Ruddle, Ryan Fleming, Nazzareno Dimasi, Ronald Herbst, Arnaud Tiberghien, Luke Masterson, Philip Howard, Kenneth Anderson, David Tice. The lysosomal transporter SLC46A3 is a potential predictive biomarker for antibody-drug conjugates bearing the non-cleavable warheads SG3376 and DM1 [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 567.
Abstract 5713: Promising predictive biomarkers for immunotherapy in metastatic melanoma
Authors: Nyakas Marta , Aamdal Elin , Guren Tormod , Aamdal Steinar , Jacobsen Kari Dolven , Brunsvig Paal , Tasken Kristin Austlid , Mælandsmo Gunhild , Yndestad Arne , Halvorsen Bente , Aukrust Paal , Ueland Thor
Published: August 2018

Aim: to explore biomarkers in order to predict outcome in patients with metastatic melanoma who have had immunotherapy with ipilimumab in a real-world setting. Metastatic melanoma is a very aggressive, incurable cancer with historically few therapeutic options and poor survival. Immunotherapy represents a revolution for metastatic melanoma treatment but there is a lack of biomarkers to predict treatment response. Material and methods: In the Norwegian National Phase 4 Multicenter Study, IPI4, 150 patients were included to receive ipilimumab (anti-CTLA3). A subgroup of 73 patients (4 screening failure) was included at Oslo University Hospital -The Norwegian Radium Hospital. Serum was available from 56 patients of this subgroup and were examined before and during ipilimumab treatment concerning possible predictive biomarkers. Expression of a panel of 17 inflammatory markers reflecting different inflammatory pathways including extra cellular matrix remodeling and fibrosis, vascular inflammation, notch signaling, inflammation in general and monocyte/macrophage activation were measured at baseline and at the 2nd and/or 3rd treatment with ipilimumab. Results: During an average 33.7 months follow-up, 33 (59%) patients died. Six promising candidates (endostatin, osteoprotegerin, C-reactive protein, pulmonary and activation-regulated chemokine and galectin-3 binding-protein) were higher in non-survivors. In particular, high endostatin and galectin-3 binding protein levels were independently associated with poor long time survival also in adjusted analysis (age, gender, lactate dehydrogenase). A 1 standard deviation (SD) increase in Gal3BP gave a 1.8 x times higher risk of death (95% CI 1.10-2.95, p=0.019) while a 1 SD increase in endostatin was associated with a 2x higher risk of death (95% CI 1.12-3.64, p=0.020) in the final model. Conclusion: Endostatin and galectin-3 binding protein may represent biomarkers for prognosis during immunotherapy with ipilimumab and should be further evaluated.

Citation Format: Marta Nyakas, Elin Aamdal, Tormod Guren, Steinar Aamdal, Kari Dolven Jacobsen, Paal Brunsvig, Kristin Austlid Tasken, Gunhild Mælandsmo, Arne Yndestad, Bente Halvorsen, Paal Aukrust, Thor Ueland. Promising predictive biomarkers for immunotherapy in metastatic melanoma [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 5713.
Abstract 573: BRAF, KRAS, and NRAS mutations in archival tumor samples and samples of cell-free DNA from serum and bone marrow aspirates from patients with multiple myeloma
Authors: Janku Filip , Li Qian , Huang Helen J. , Wang Yafei , Cao Zeng , Karlin-Neumann George , Liu Zhiqiang
Published: August 2018

Background: Oncogenic mutations in BRAF, KRAS and NRAS genes have been reported in multiple myeloma and can be explored as biomarkers for selection of targeted therapies. Methods: Unamplified DNA from archival tumor tissue samples and cell-free DNA (cfDNA) from serum and bone marrow aspirates from patients with multiple myeloma was tested for BRAF V600, KRAS G12/G13, NRAS G12/G13 and NRAS Q61 mutations using multiplex assays for droplet digital PCR (Bio-Rad). Agreement among methods was evaluated and results were compared to clinical outcomes. Results: Of 88 patients with multiple myeloma (stage I, 13 [15%]; stage II, 26 [30%]; stage III, 34 [39%]; stage unknown, 15 [17%]), 4 (5%) patients were found to have BRAF V600 mutation (all confirmed V600E), 15 (17%) KRAS G12/G13 mutation, 3 (3%) NRAS G12/G13 mutation and 16 (18%) NRAS Q61 mutation in archival tumor tissue. Most mutations were subclonal with a median variant allelic frequency (VAF) 1.55% (range, 0.13%-34%). Survival data were available for 47 patients and patients with high mutation VAF had a trend to shorter survival than patients with low mutation VAF (25.3 months vs. not reached, P=0.087). Of 88 patients, 22 (25%) had simultaneous serum cfDNA collection, which demonstrated BRAF V600 mutation in 7 (32%; 3 confirmed as V600E), KRAS G12/G13 mutation in 2 (9%), NRAS G12/G13 mutation in 0 (0%) and NRAS Q61 mutation in 4/22 (18%) of samples and median VAF was 2.9% (range, 0.34%-18.8%). Agreement rates for serum compared to tissue were 73% for BRAF V600, 95% for KRAS G12/G13, 100% for NRAS G12/G13 and 95% for NRAS Q61. In addition, 13 (15%) patients had simultaneous bone marrow aspirate cfDNA collection, which demonstrated BRAF V600 mutation in 1 (8%; confirmed as V600E), KRAS G12/G13 mutation in 0 (0%), NRAS G12/G13 mutation in 0 (0%) and NRAS Q61 mutation in 1 (8%) of samples. Agreement rates for bone marrow aspirates compared to tissue were 100% for BRAF V600, 92% for KRAS G12/G13, 100% for NRAS G12/G13 and 100% for NRAS Q61. Conclusion: Common oncogenic mutations in BRAF, KRAS and NRAS genes are prevalent with relatively low VAF in multiple myeloma and can be detected with sensitive techniques such as ddPCR. Their prognostic significance and therapeutic utility needs to be further investigated.

Citation Format: Filip Janku, Qian Li, Helen J. Huang, Yafei Wang, Zeng Cao, George Karlin-Neumann, Zhiqiang Liu. BRAF, KRAS, and NRAS mutations in archival tumor samples and samples of cell-free DNA from serum and bone marrow aspirates from patients with multiple myeloma [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 573.
Abstract 5733: IL-11 as a therapeutic target to treat colorectal cancer
Authors: Huynh Jennifer , Chand Ashwini , Ernst Matthias
Published: August 2018

Introduction Colorectal cancer is a pressing health concern and there is a demand to develop novel therapeutics and improve current therapies to treat this disease. Immune checkpoint inhibitors (i.e. anti-PD-1 treatment) have been highly successful for the treatment of solid malignancies however, the majority of colorectal cancers do not typically respond to immunotherapy. Accumulating evidence alludes to a role for IL-11 signaling in tumor development although the mechanisms underlying IL-11 biology in colorectal cancer remain largely unknown. We postulate that IL-11 could be a mode of immunosuppression which can be targeted to overcome the poor responses of colorectal cancer to immunotherapy. Here we aim to investigate IL-11 signaling as a therapeutic strategy which can also be targeted in combination with anti-PD-1 treatment. Moreover, we present data that indicates an immunological function for IL-11 in modulating T cell anti-tumor activity.

Method To assess the therapeutic potential for targeting IL-11 signaling in colon cancer in vivo, wild type and Il11r-/- C57BL/6 mice were injected subcutaneously in the flank on Day 0 with 1 x 106 MC38 colon cancer cells. The mice were then treated with an anti-PD-1 antibody i.p. dose once every 3 days. Mice were euthanised at Day 18. Harvested tumors were analysed by FACs and immunohistochemistry. To ascertain a role for IL-11 signaling in T cell activity, CD8+ and CD4+ T cells were FACs-sorted from wild type and il11r-/- mice, and activated with PMA/ionomycin for 24h. T cell activation was assessed by measuring mRNA levels of granzyme B and perforin by qPCR, and IFNγ production by ELISA.

Results MC38 growth was attenuated in il11r-/- mice compared to wild type hosts. Lower tumor burden corresponded with a modest increase in tumor-infiltrating CD8+ T cells however we observed no differences in other immune cell subtypes (i.e. CD4+ T cells, MDSCs and macrophages). In addition, lower tumor burden corresponded with a marked reduction in Ki67 as assessed by immunohistochemistry. In addition, T cells harvested from il11r-/- hosts expressed lower levels of granzyme B, perforin and IFNγ under both basal conditions and following PMA/ionomycin stimulation.

Conclusion Here we report that IL-11 signaling supports tumorigenesis using the MC38 colon cancer mouse model. For the first time, we have characterized a functional role for IL-11 in modulating T cell function. Overall, the findings from this study indicate IL-11R as a potential therapeutic target to improve the efficacy of immune checkpoint inhibitors for the treatment of colorectal cancer.

Citation Format: Jennifer Huynh, Ashwini Chand, Matthias Ernst. IL-11 as a therapeutic target to treat colorectal 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 5733.
Abstract 5734: Interleukin-1 signaling is required for HNSCC tumor response to cetuximab
Authors: Espinosa-Cotton Madelyn M. , Dahl Rachel A. , Fertig Elana , Jensen Isaac , McLaren Ayana J. , Miller Kenley , Rodman Samuel N. , Schmitz Sandra , Simons Andrean L.
Published: August 2018

Despite the incorporation of the epidermal growth factor receptor (EGFR) inhibitor cetuximab into the clinical management of head and neck squamous cell carcinoma (HNSCC), limited to no long-term changes in overall survival are observed in HNSCC patients even though EGFR is expressed at high levels in these tumors. Therefore, the identification of novel therapeutic approaches to enhance the clinical efficacy of cetuximab could lead to improved long-term survival for HNSCC patients. Our previous work suggests that cetuximab activates the interleukin-1 (IL-1) pathway via tumor release of IL-1 alpha (IL-1α), although the implications of activating this pathway are unclear. The IL-1 pathway plays a central role in immune response and displays both pro-tumor and anti-tumor activities. IL-1 may promote tumor growth by upregulating the secretion of pro-inflammatory mediators involved in angiogenesis and metastasis. On the other hand, IL-1 signaling may promote antitumor immunity specifically via natural killer (NK)-cell mediated antibody-dependent cell-mediated cytotoxicity (ADCC), which is also an important mechanism of action of cetuximab. The goal of our work is to determine how modulation of the IL-1 pathway affects HNSCC tumor response to cetuximab. We found that blockade of IL-1 signaling using an IL-1-receptor antagonist (IL-1RA, anakinra), neutralizing IL-1α/IL-1β antibodies, and genetic knockdown of the IL-1R all suppressed the anti-tumor efficacy of cetuximab, while IL-1α overexpression and treatment with recombinant IL-1α enhanced HNSCC tumor response to cetuximab in immunodeficient and immunocompetent HNSCC mouse models. Mechanistically, these results appear to be due to modulation of ADCC, as we found that IL-1 blockade significantly reduced cetuximab-mediated ADCC in vitro. Additionally, we found that HNSCC patients with high baseline circulating levels of IL-1 ligands (IL-1α, IL-1β) were significantly more likely to respond favorably to cetuximab monotherapy compared to patients with low or no baseline circulating IL-1 ligands. Altogether, these results suggest that IL-1 signaling is necessary for HNSCC tumor response to cetuximab. Therefore, IL-1α warrants further study as a novel therapeutic to enhance response to cetuximab and as an immunologic biomarker for cetuximab response.

Citation Format: Madelyn M. Espinosa-Cotton, Rachel A. Dahl, Elana Fertig, Isaac Jensen, Ayana J. McLaren, Kenley Miller, Samuel N. Rodman, Sandra Schmitz, Andrean L. Simons. Interleukin-1 signaling is required for HNSCC tumor response to cetuximab [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 5734.
Abstract 5741: Dexamethasone suppresses cytokine-induced dual oxidase 2 and VEGF-A expression in human pancreatic cancer cells in vitro and pancreatic cancer growth in xenografts
Authors: Wu Yongzhong , Doroshow James H.
Published: August 2018

Chronic pancreatic inflammation is strongly associated with pancreatic cancer. We previously demonstrated that inflammatory cytokines interact to produce a DUOX2 -dependent, reactive oxygen species (ROS)-related, pro-oxidant milieu that could increase the pathologic potential of pancreatic inflammation, enhancing malignant transformation. Furthermore, we have shown that DUOXuox2 expression is upregulated in patients with chronic pancreatitis as well as pancreatic ductal adenocarcinoma (PDAC). Dexamethasone (Dex) has been reported to inhibit PDAC invasiveness, the formation of pancreatic intraepithelial neoplasia in genetically-engineered mouse models of pancreatic cancer, as well as epithelial to mesenchymal transition in PDACs, and local tumor recurrence and metastasis in vivo. Using cultured human pancreatic cancer cell lines, we found that in a dose- and time-dependent fashion Dex inhibited cytokine (IFN-γ/LPS, IL-4, and IL-17)-mediated up-regulation of DUOXuox2 and VEGF-A expression in several human pancreatic cancer cell lines, including BxPC-3, ASPC-1, and CFPAC-1. Dex pretreatment also blocked DUOX2-related DNA double strand breaks (detected as activated γH2AX) and the expression of HIF-1α in PDAC cells treated with pro-inflammatory cytokines. The effects of Dex were abolished by pre-treatment with the Dex antagonist RU-486. As expected, we did not observe anti-proliferative effects of Dex on PDAC cells in vitro. However, Dex strongly repressed DUOXuox2 mRNA and protein expression as well as the growth of xenografts initiated from BxPC-3 cells; in contrast, for the MIA-Paca line that is unresponsive to cytokines in culture, Dex produced no effect on DUOXuox2 expression and tumor growth when these cells were grown as xenografts. Examination of the human DUOXuox2 promotor in silico revealed a putative negative glucocorticoid receptor (GR) binding element. Western analysis, using nuclear extracts from pancreatic cancer cells treated with Dex, revealed that both activated glucocorticoid receptor and certain co-repressors, such as NCOR-1/2 and histone deacetylases (HDAC1, 2, and 3) exist in human pancreatic cancer cell nuclei. Our ongoing experiments are focused on understanding the molecular mechanism of Dex-mediated DUOXuox2 repression both in vitro and in vivo. In summary, these studies suggest that cytokine-related oxidant stress, generated by Duox2, could play a role in the progression of pancreatic cancer.

Citation Format: Yongzhong Wu, James H. Doroshow. Dexamethasone suppresses cytokine-induced dual oxidase 2 and VEGF-A expression in human pancreatic cancer cells in vitro and pancreatic cancer growth in xenografts [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 5741.