bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1497: A PRC2 independent role of EZH2 in androgen receptor signaling in prostate cancer
Authors: Lee Yongik , Kim Jung a , Changsheng Zhao , Lu Xiadong , Fong Ka Wing , Yu Jindan
Published: August 2018

Prostate cancer is the most frequently diagnosed cancer and third most frequent cause of cancer deaths in US males. Prostate cancer patients have benefitted from androgen deprivation therapy and small molecular inhibitors targeting androgen receptor (AR). However, 30% of patients have primary resistance to both forms of treatment with a majority of patients eventually developing resistance to these therapies and progressing from androgen dependent prostate cancer (ADPC) to castration resistant prostate cancer (CRPC). Unfortunately, there are no effective therapeutic options available for CRPC patients, so novel and more effective therapeutic strategies for CRPC are urgently needed. Enhancer of Zeste 2 (EZH2) is a well-characterized oncogene that is one of the most highly upregulated genes in aggressive PCa and suggested as a prognostic biomarker. EZH2 is a part of polycomb repressive complex2 (PRC2) with embryonic ectoderm development (EED) and suppressor of zeste 12 (SUZ12) to function as a repressor through the SET domain, especially Histidine 689 to methylate H3K27. Recently, some studies suggest a context-dependent or PRC2 independent function of EZH2, but new functional role of EZH2 in cancer that are yet to be delineated. In the present study, we demonstrated EZH2 enhances AR signaling through direct AR promoter occupancy at exon1, independent of histone methyltransferase activity. EZH2 has a dual role as a transcriptional activator mediated by AR and an epigenetic silencer mediated by H3K27me3. Therefore, simultaneously targeting EZH2 and AR by drug inhibitors, EPZ and enzalutamide (Enz), respectively, leads to synergistic cell growth inhibition. Taken together, our data reveal a dual function of EZH2 in PCa as a transcriptional activator and an epigenetic silencer. We believe that this study provide not only a novel function of EZH2 in the regulating AR signaling pathway but also provide novel therapeutic strategies for advanced prostate cancer which currently has no therapeutic options available.

Citation Format: Yongik Lee, Jung a Kim, Zhao Changsheng, Xiadong Lu, Ka Wing Fong, Jindan Yu. A PRC2 independent role of EZH2 in androgen receptor signaling 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 1497.
Abstract 1503: Arsenic trioxide inhibits proliferation of acute leukemia cells through reduced expression of E2F1, cyclin E, and activation of retinoblastoma protein
Authors: Kumar Sanjay , Tchounwou Paul
Published: August 2018

Arsenic trioxide (ATO) is has been used successfully in the treatment of all age group of acute promyelocytic leukemia (APL) patients in both induction and consolidation therapy. It inhibits growth APL cells through various mechanism including oxidative stress, cell cycle regulation, and apoptosis. However, detail molecular mechanism ATO-induced APL cell proliferation inhibition mostly poorly known. E2F1, a transcriptional factor widely involved proliferation and differention of many types of cancer cells through providing signal to accumulation p53, cell cycle regulation, and apoptosis. We hypothesized that ATO inhibits proliferation and differentiation of APL cells through reduced expression of E2 F1, cyclin E and stimulation of retinoblastoma and AMPKα2 expressions in APL cells. To test hypothesis, we used APL cell lines and after treatment with different concentration (2,4,6, and 8μg/ml) ATO, checked expression level of E2F1, cyclin A, cyclin E, Akt, retinoblastoma (Rb D20 & H1) and AMPKα2 by western blotting, immunocytochemistry, and confocal imaging. We found that it reduced expression significantly of E2F1, cyclin E by modulating expression profile of retinoblastoma (Rb D20 & H1), Akt and AMPKα2 proteins in APL cells concentration dependent manner. Our data showed that E2F1 associated with p53 and its association may involve ATO -induced cell cycle regulation and apoptosis. On the basis of these findings, we conclude that ATO inhibits APL cells proliferation by reducing E2F1, cyclin E expression through stimulation of retinoblastoma (Rb D20 & H1), Akt , and AMPKα2 proteins. It is novel mode of action of ATO in APL cells and may help in the designing of new anti-leukemic drugs for treatment of APL patients more efficiently and quickly.

Keywords: Arsenic trioxide, E2F1, cyclin E, Rb proteins, AMPKα2, and APL cells.

Acknowledgements: This research was financially supported by National Institutes of Health NCRR Grant No. 5G12RR013459 and MIMHD Grant No. 8G12MD007581, through the RCMI-Center for Environmental Health at Jackson State University.

Citation Format: Sanjay Kumar, Paul Tchounwou. Arsenic trioxide inhibits proliferation of acute leukemia cells through reduced expression of E2F1, cyclin E, and activation of retinoblastoma protein [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 1503.
Abstract 1505: GATA3 expression is associated with poor differentiation of osteosarcoma cells
Authors: Hiraoka Koji
Published: August 2018

Objective: GATA3, a transcriptional factor promoting differentiation of Th2 cells, was expressed in breast cancer cells or bladder cancer cells. We reported that Gata3 expression in soft tissue sarcoma is an independent factor for poor prognosis. However, the role of GATA3 in osteosarcoma is unknown. We investigated whether GATA3 expression is associated with cell differentiation or clinical prognosis of osteosarcoma. Methods: We examined whether decreased GATA3 expression in MG63 osteosarcoma cells by induction of siRNA GATA3 using electroporation affects cell differentiation. We also evaluated GATA3 expression in biopsy samples of 31 osteosarcoma cases using immunohistochemical analysis, and statistically compared clinicopathological characteristics of GATA3-positive and GATA3-negative cases. In particular, the correlation between osteoid formation and GATA3 expression was examined. Result: GATA3 expression was observed in MG63 cells by Western blotting and real-time PCR. Decreased GATA3 expression caused by induction of siRNA promoted the expression of the osteoblast differentiation markers; osteopontin, osteocalcin and RUNX2; in MG63 cells, while ALP and DMP-1, pre-osteocyte markers, had not increased. The expression of p21, one of the differentiation markers of osteosarcoma, is also elevated by decreased GATA3 expression. GATA3 significantly expressed in osteosarcoma cases with less osteoid formation (P<0.001), although no significant correlation between GATA3 expression and clinical prognosis was observed. Conclusion: These data indicated that GATA3 expression might be associated with poor differentiation of osteosarcoma cells. GATA3 may be a target to treat for osteosarcoma through promotion of cell differentiation.

Citation Format: Koji Hiraoka. GATA3 expression is associated with poor differentiation of osteosarcoma 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 1505.
Abstract 1521: Role of Trim28 in prostate cancer
Authors: Fong Ka-Wing , Zhao Jonathan , Zheng Bin , Yu Jindan
Published: August 2018

TRIM28 is an essential gene during embryonic development, which is involved in a wide range of biologic processes. From the pathologic viewpoint, TRIM28 overexpression was proved to broadly exist in pancreatic, liver, breast, glioma and lung cancer, and often expression of TRIM28 is correlated with clinical stage. Functional assays have demonstrated that TRIM28 promotes cancer cell growth and metastasis, further supporting TRIM28 as a promising target for therapeutic intervention. For past decade, TRIM28 is considered to be a transcriptional co-repressor due to TRIM28-dependent recruitment of histone modifiers such as CHD1/NuRD complex and SETDB1 for histone methylation and heterochromatin formation to achieve gene silencing. Surprisingly, transcriptome study revealed that TRIM28 can activate the expression of its target genes as much as it represses, hypothesizing the main role of TRIM28 may not lie in transcriptional repression. In addition, recent findings demonstrated that TRIM28 interacts with 7SK snRNP complex, which facilitates P-TEFb kinase module recruitment and productive transcription elongation at inducible genes. This evidence implicated that TRIM28 may form distinct complexes to induce or repress gene expression in context-dependent manner. On top of that, it remains unclear about the role of TRIM28 in prostate cancer. Our preliminary study revealed that TRIM28 is upregulated in castration-resistant prostate cancer (CRPC). TRIM28 knockdown markedly decreased prostate cancer cell proliferation, clonogenicity as well as CRPC-xenograft tumor growth. Moreover, proteomic analysis in LNCaP prostate cancer cells revealed that TRIM28 associates with a number of transcription co-activators. Gene expression profiling showed that androgen signaling is positively regulated by TRIM28. We proposed that TRIM28 forms the transcription activation complexes that modulate gene expression of various oncogenic pathway and promote PCa progression.

Citation Format: Ka-Wing Fong, Jonathan Zhao, Bin Zheng, Jindan Yu. Role of Trim28 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 1521.
Abstract 1535: T Cells engineered to express the IL-13Rα2 specific CAR and a PD-L1 specific switch receptor show increased anti-tumor activity in the Glioblastoma tumor microenvironment
Authors: Castro Abel De , Keys Megan E. , Arroyo Jonathan , Prosser Megan E.
Published: August 2018

Glioblastoma multiforme (GBM) is an aggressive brain cancer with poor prognosis with traditional treatments such as chemotherapy and radiotherapy, which often leave lasting and pervasive damage to the individual. GBM cells upregulate the surface protein interleukin 13 receptor subunit alpha-2 (IL13Rα2), which can be targeted as a novel immunotherapeutic marker for the immune response to be initiated. In this study, IL13Rα2 is targeted using a first generation chimeric antigen receptor (CAR) that contains an intracellular zeta chain domain. However, a limitation to this approach is that the tumor microenvironment exhausts the T cells that interact with the tumor through a receptor-mediated response. Programmed Death Ligand 1 (PD-L1) is a molecule that is expressed on cancerous cells that binds to Programmed Death 1 (PD-1) on T cells. When the ligand binds to PD-1 on T cells, there is decreased T cell proliferation, cytokine production, and anti-tumor activity. This problem can be avoided via creation of a switch receptor with a PD-1 extracellular domain fused to transmembrane and intracellular costimulatory CD28, which converts tumor mediated inhibition into stimulation upon ligation of PD-L1. It is hypothesized that the incorporation of additional costimulatory domains will enhance the stimulatory effects of the switch receptor. Engineered T cells expressing varied switch receptors in conjunction with the IL13Rα2-specific CAR have been created and have been assessed in vitro as a basis for glioblastoma treatment. Tests performed include cytokine secretion and T-cell proliferation assays. Results of these preliminary studies suggest that the the inclusion of additional costimulatory domains in the switch receptor design may be advantageous in enhancing anti-tumor responses in the GBM microenvironment.

Citation Format: Abel De Castro, Megan E. Keys, Jonathan Arroyo, Megan E. Prosser. T Cells engineered to express the IL-13Rα2 specific CAR and a PD-L1 specific switch receptor show increased anti-tumor activity in the Glioblastoma 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 1535.
Abstract 1539: In vivo study of natural killer cell cytotoxicity against cholangiocarcinoma in a nude mouse model
Authors: Jung Inhye , Kim DoHee , Chung Yong Yoon , Park Seung Woo , Yoo Da Kyung
Published: August 2018

NK cell is one of the lymphocytes clinically used for various cancer types. Cytotoxicity of NK cell to cholangiocarcinoma (CC), however, has not been studied yet, nor has NK cell therapy against CC been clinically applied. In this study, relevance of NK cell therapy for antitumor efficacy against CC was preclinically investigated. Human HuCCT-1 cells, an intrahepatic CC cell line, were xenografted into nude mice. The HuCCT-1 tumor-bearing nude mice then received multiple infusions of ex vivo expanded human NK cell (SMT01) and were evaluated for in vivo cytotoxic activity of the NK cells. Dosage-dependent safety and toxicity of SMT01 was evaluated at three different dose levels. The mice well tolerated the maximum dose of SMT01. All of the three dosage groups did not show any significant adverse event. To evaluate in vivo activity of SMT01 against CC, we administered 5 infusions of SMT01 into the HuCCT-1 tumor-bearing nude mice. A standard chemotherapy as a positive control was also included. The result showed that SMT01 infusions resulted in significant inhibition of the CC tumor growth compared to the negative control (normal saline infusion), suggesting that NK cell contains in vivo cytolytic activity against cholangiocarcinoma. When body weights of the nude mice were measured, however, the body weight of the nude mice administered with chemotherapy was found to be maintained as lowest among all treatment groups while all the NK cell infusion groups well maintained the body weight during the treatment, suggesting beneficial effect of NK cell therapy in relevance of quality of life. IHC experiments and TUNEL assay using the tumor tissue sections clearly supported the cytotoxicity results of SMT01 against CC. We found that a robust infiltration of the infused NK cells was located along the loose tissue where feeding vessels entered. TUNEL-positive tumor cells were mainly localized at the vicinity of populated NK cells. In conclusion, our in vivo study demonstrates that NK cell also contains cytolytic activity against cholangiocarcinoma. Further investigation of the NK cell-based immunotherapy can be useful to determine cancer therapeutics for the specific tumor.

Citation Format: Inhye Jung, DoHee Kim, Yong Yoon Chung, Seung Woo Park, Da Kyung Yoo. In vivo study of natural killer cell cytotoxicity against cholangiocarcinoma in a nude mouse model [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 1539.
Abstract 1541: Directed, unbiased mapping of lentiviral integrations with next generation sequencing in CAR-T cells
Authors: Johnstone Timothy G. , Chari Rajagopal , Koppstein David , Hause Ronald J. , Ponce Rafael , Briggs Adrian W. , Vigneault Francois
Published: August 2018

During manufacturing of an exemplary CD19-directed CAR-T cell product, patient T cells were transduced with a viral vector encoding the CD19-directed, 41BBζ endodomain-containing chimeric antigen receptor (CAR) construct, enabling permanent genetic modification of the target T cells. Lentiviral transduction with a self-inactivating (SIN) vector can offer certain advantages in safety and consistency over other DNA delivery methods. Although the integration patterns of wildtype HIV-1 have been well-characterized and shown to have a low risk of insertional transformation, the addition of an artificial construct may have the potential to affect integration patterns. Existing techniques for viral integration mapping, such as ligation-mediated polymerase chain reaction (LM-PCR), have limitations precluding comprehensive, unbiased, high-throughput insertion site mapping. To characterize insertional events in engineered CAR-T cells, we developed an unbiased NGS assay and computational pipeline capable of characterizing viral integration events genome-wide. The method leverages Tn5 transposase, coupled with a long terminal repeat-specific PCR, to map integration events down to nulceotide resolution. This assay identified over 150,000 high-confidence integration events across 23 patient-derived CAR-T cell products. Analysis of these sites revealed a similar integration preference to lentiviruses described in the literature: driven by GC content, local nucleotide content, chromatin status, and transcriptional activity, with no indication of preferential integration at oncogenic loci. In conclusion, in this assay a CD19-directed, CAR-containing lentivirus exhibited a low risk integration profile with no significant evidence of construct-specific risk factors. Furthermore, the findings suggest that the NGS assay may be useful for more efficient, cost-effective, and sensitive measurement of CAR-T integration events for a range of constructs.

Citation Format: Timothy G. Johnstone, Rajagopal Chari, David Koppstein, Ronald J. Hause, Rafael Ponce, Adrian W. Briggs, Francois Vigneault. Directed, unbiased mapping of lentiviral integrations with next generation sequencing in CAR-T 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 1541.
Abstract 1563: Characterization of two new recombinant rabbit anti-PDL1 IHC staining in bladder cancer, NSCLC, and melanoma with immune cell markers
Authors: Gonzalez Rachel M. , Fu Wei , Logis Evelin , Ding Emma , Chen Casey , Li Xiaojie , Merritt Sonia , Liu Mingjuan , Zhang Amy , Wang Yiran , Wang Guangli , Ma Donghui
Published: August 2018

Published studies show tumor cells overexpress PD-L1 to escape the host immune defense by binding to PD-1 on surveilling T-cells causing the T-cells to shut down. Immunotherapies disrupting PD-1/PD-L1 signaling interactions have great success in treating PD-L1 positive tumors. Immunohistochemistry (IHC) is an important diagnostic tool currently used to determine the expression level of PD-L1 in tumor and immune cells. The FDA approved PD-L1 clones (SP142 and 28-8) for IHC present different staining patterns when evaluated on the same tumor tissue. In this study, we assessed both the immune cells and tumor cells IHC positive stain of PD-L1. To do this we evaluated multiple immune cell markers with multiple PD-L1 antibodies. IHC screens were done with 5 PD-L1 antibodies, 2 recombinant rabbit monoclonal antibodies (clone OR-5E3 and OR-5H8), the mouse monoclonal antibody (clone UMAB229), and the FDA approved clones (SP142 and 28-8). The immune cell markers used were CD3, CD8A, CD20, CD68, and FOXP3. NSCLC, Bladder Cancer, and Melanoma immune cells, as indicated by the CD3, CD8A, CD20, CD68 and FOXP3 staining, generated different distribution pattern in the three tumor types. The five PD-L1 antibodies did show variation in detection of both the immune and tumor cells. For example, PD-L1 clones OR-5E3 and OR-5H8 stained tumor cells stronger and picked up weak expression of PD-L1 better than clone SP142, suggesting the two antibodies have higher affinity. The mouse monoclonal anti-PDL1 clone UMAB229 picked up strong and weak staining similar or better than clones OR-5H8 and picked up the immune cells similar to SP-142. The five PD-L1 antibodies were made from different antigens which may contribute to their sensitivity and specificity to detect PD-L1 in tumor cells. This study suggests the new generation of PD-L1 antibodies may make a better tool for diagnostic screens.

Citation Format: Rachel M. Gonzalez, Wei Fu, Evelin Logis, Emma Ding, Casey Chen, Xiaojie Li, Sonia Merritt, Mingjuan Liu, Amy Zhang, Yiran Wang, Guangli Wang, Donghui Ma. Characterization of two new recombinant rabbit anti-PDL1 IHC staining in bladder cancer, NSCLC, and melanoma with immune cell markers [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 1563.
Abstract 1591: Cell-free DNA quantification reflects survival in non-small cell lung cancer patients with low metabolic tumor burden
Authors: Hyun Myung Han , Lee Eun Sung , Eo Jae Seon , Sung Jae Sook , Kang Eun Joo , Choi Yoon Jee , Park Kyong Hwa , Shin Sang Won , Lee Sung Yong , Kim Yeul Hong
Published: August 2018

We aimed to assess the role of tumor biological behavior/aggressiveness measured by cell-free DNA (cfDNA) quantification according to metabolic tumor burden measured by FDG-PET/CT scan to predict survival of advanced non-small cell lung cancer (NSCLC). Newly-diagnosed eighty-two NSCLC patients with baseline cfDNA quantification and positron emission tomography/computed tomography (PET/CT) scan were prospectively enrolled. The cfDNA level was quantified by Agilent High Sensitivity DNA kit. Metabolic tumor burden was measured by metabolic tumor volume (MTV) and total lesion glycolysis (TLG) from PET/CT scan. The optimal cut-off value for cfDNA quantification, MTV, and TLG were found using X-tile analysis. The high-cfDNA quantification is associated with poor overall survival (OS) (hazard ratio=2.71, 95% confidential interval=1.33-5.52; p=0.006) than that of low. After categorized by metabolic tumor burden, however, the patients with high-MTV showed poor prognosis regardless of cfDNA quantification (low-cfDNA quantification vs high-cfDNA quantification, median OS = 3.9 months vs 7.0 months; p value > 0.05). On the other hands, the patients with high-cfDNA quantification showed poor prognosis in patients with low-MTV (low-cfDNA quantification vs high-cfDNA quantification, median OS = 52.8 months vs 22.9 months; p values < 0.001). According to baseline TLG level, the role of cfDNA quantification to predict survival was similar to MTV. Although cfDNA quantification independent prognostic factors for OS, the significance was disappeared when adjusted by MTV or TLG. This finding provides novel insights that the cfDNA quantification reflect survival for selected patients with low metabolic tumor burden in NSCLC.

Citation Format: Myung Han Hyun, Eun Sung Lee, Jae Seon Eo, Jae Sook Sung, Eun Joo Kang, Yoon Jee Choi, Kyong Hwa Park, Sang Won Shin, Sung Yong Lee, Yeul Hong Kim. Cell-free DNA quantification reflects survival in non-small cell lung cancer patients with low metabolic tumor burden [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 1591.
Abstract 1618: Simultaneous isolation of exosomes and cfDNA from liquid biopsies using universal kit based on SubX-MatrixTM technology
Authors: Malykh Andrei G. , Malek Anastasia , Lokshin Anna , Evtushenko Vladimir
Published: August 2018

In 2016 we have developed novel approach for isolation of circulating cell-free DNA employing the proprietary bi-functional substance SubX® that tightly binds DNA and forms sandwich [cfDNA- SubX®-magnetic particles]. These sandwich aggregates are easily separated from bio-liquid with magnet followed by cfDNA isolation by speedy protocol. Our approach does not require Proteinase K digestion and 2-3-fold dilution of bio-liquid with lysis/binding buffer in contrast to all commercially available kits. Our kit has been evaluated in various research and clinical labs for cfDNA isolation from serum, plasma and urine of patients with different forms of cancer. SubX®-approach also allows for isolation of cfDNA from large volumes of urine samples without its concentration. We demonstrated linear increase of the DNA yield with liquid biopsy volume. Another unique property of the SubX® is that both ends of the molecule display lipid binding groups. This feature allows each molecule of SubX® to anchor two exosomes (i.e. dimerize). Excess of SubX® molecules in the solution results in aggregation of up to 10-15 exosomes and formation of micron-size particles that are easily precipitated in a brief 14K x g (or 30 min 2K x g) centrifugation step. A specially designed buffer allows for reconstitution of the pelleted exosomes back to monomer format for downstream applications. Flow cytometry with specific surface marker CD9 confirmed that SubX®-aggregated vesicles are exosomes. Analysis of membrane-bound protein markers and microRNA profile of exosomes isolated from plasma of prostate cancer patients will be presented. Difference in SubX® binding strength for cfDNA and exosomes allows for consequent isolation from the [cfDNA/exosomes- SubX®-magnetic particles] pellet first exosomes, then cfDNA. Eventually, we combined both approaches in one kit for isolation of cfDNA and exosomes from the same sample. This simultaneous isolation protocol is simple and fast, it allows to employ minimal volume of valuable bio samples as well as to reduce labor and cost. The kit was validated in serum and urine samples from patients with ovarian and pancreatic cancer. Exosome nature of isolated vesicles was confirmed by three independents methods - light scattering, immunological and electron microscopy. Thus, one could analyze both genetic (DNA and RNA) as well as protein markers present in the same liquid biopsy sample.

Citation Format: Andrei G. Malykh, Anastasia Malek, Anna Lokshin, Vladimir Evtushenko. Simultaneous isolation of exosomes and cfDNA from liquid biopsies using universal kit based on SubX-MatrixTM technology [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 1618.
Abstract 1634: BRCA-like phenotype constitutes hallmark of osteosarcoma
Authors: Kovac Michal , Ribi Sebastian , Blattmann Claudia , Nathrath Michaela , Baumhoer Daniel
Published: August 2018

Background: Osteosarcomas are aggressive bone tumours with a high degree of genetic heterogeneity, which limits treatment options in patients who do not respond to standard chemotherapy.

Methods: We sequenced 104 exomes and low-coverage genomes from 14 time-series consisting of chemotherapy-naïve biopsies, resection specimens, locally recurring tumours and/or distant metastases. We then identified cancer driver mutations, signatures of mutation processes and reconciled clonal structures of tumours with phylogenetic trees, thus building and evolutionary history of each tumour. Where possible, we searched for the evidence of selection acting on the tumours and molecular hallmarks that could be therapeutically exploited.

Results: Interrogating genomic data from time series, we identified pathogenic mutations in at least 10 cancer genes, but there was no universal cancer driver event present in the majority of tumours at any given time point. However, >80% of osteosarcomas exhibited specific combination of single-base substitutions, LOH and large-scale genome instability characteristic of BRCA1/2-deficient tumours. In osteosarcoma, "BRCAness" developed recurrently through independent BRCA1/2 mutations and mutations in their binding partners such as PALB2 or CHEK2. We therefore investigated the sensitivity of a panel of osteosarcoma cell lines to the poly(ADP)-ribose polymerase inhibitor talazoparib. In combination with temozolomide, talazoparib led to the to good response of osteosarcoma cell lines, activation of BAX and BAK, loss of mitochondrial membrane potential, DNA fragmentation and caspase-dependent cell death.

Conclusion: The acquisition of a BRCA-like phenotype in osteosarcoma has implications for the development of novel treatment strategies using PARP inhibitors alone, or together with standard chemotherapy.

Citation Format: Michal Kovac, Sebastian Ribi, Claudia Blattmann, Michaela Nathrath, Daniel Baumhoer. BRCA-like phenotype constitutes hallmark of osteosarcoma [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 1634.
Abstract 1639: Androgen receptor and ALDH1 expression among internationally diverse patient populations
Authors: Jiagge Evelyn M. , Jibri Aisha , Bensenhaver Jessica , Wicha Max , Awuah Baffour , Merajver Sofia , Newman Lisa
Published: August 2018

Background: Population-based incidence rates of breast cancers that are negative for the estrogen receptor (ER), progesterone receptor (PR), HER2/neu triple-negative breast cancer (TNBC) are higher among African American (AA) compared to White American (WA) women, and several studies suggest that TNBC prevalence is increased among selected populations of African patients. The colonial-era transatlantic slave trade resulted in shared ancestry between contemporary AA and Gh populations. The extent to which associations between TNBC are related to East African versus West African ancestry, and whether these associations extend to expression of additional hormone receptors such as androgen receptor (AR) and stem cell markers such as ALDH1, is uncertain, but this research may explain breast cancer disparities between domestic communities within the United States as well as between international population subsets.

Methods: We utilized immunohistochemistry to evaluate ER, PR, HER2/neu, AR and ALDH1 expression among White American (n=153), African American (n=76), Ethiopian (Eth)/East African (n=90), and Ghanaian (Gh)/West African (n=286) breast cancers through an IRB-approved international research program.

Results: Mean age at breast cancer diagnosis was 43, 49, 60, and 57 years for the Eth, Gh, AA, and WA patients, respectively. Frequency of TNBC was significantly higher for the AA and Gh patients (41% and 54%, respectively) compared to the WA and Eth patients (23% and 15%, respectively; p<0.001). These associations were unchanged when limited to patients age 50 years and younger (47% and 49% for AA and Gh, respectively, versus 18% and 16% for WA and Eth, respectively; p<0.001). Frequency of ALDH1 positivity was also higher for the AA and Gh tumors (32% and 36%, respectively) compared to the WA and Eth tumors (23% and 17%, respectively; p=0.007). Significant differences were also observed for distribution of AR positivity, which was 71%, 55%, 42%, and 50% for the WA, AA, Gh, and Eth cases, respectively (p=0.008). Frequency of ALDH1 expression was numerically higher in the AA, Gh, and Eth TNBC cases compared to the WA TNBC cases, but this was not statistically significant (33%, 41%, and 31%, respectively, versus 18%; p=0.47).

Conclusions: Extent of African ancestry appears to be associated with particular breast cancer phenotypes. West African ancestry correlates with increased risk of TNBC and breast cancers that are positive for ALDH1.

Citation Format: Evelyn M. Jiagge, Aisha Jibri, Jessica Bensenhaver, Max Wicha, Baffour Awuah, Sofia Merajver, Lisa Newman. Androgen receptor and ALDH1 expression among internationally diverse patient populations [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 1639.
Abstract 1641: Utilization of palliative therapies among Hispanics with stage IV non-small cell lung cancer
Authors: Duma Narjust , Durani Urshila , Molina Julian , Moynihan Timothy J.
Published: August 2018

Background: Racial disparities in the treatment of lung cancer are well documented. However, research in disparities in palliative care is limited. Early integration of palliative care in advanced non-small cell lung cancer (NSCLC) has been proven to improve quality of life and overall survival in this subset of patients. We proposed to study the use of palliative treatments for stage IV NSCLC among Hispanic patients (pts). Methods: Using the National Cancer Database (NCDB), we identified all Hispanic pts (self-reported) diagnosed with stage IV NSCLC from 2005 to 2013. Cases with incomplete data, unknown life/death status or classified as Hispanic by surname only were excluded. Hispanics were grouped based on place of origin. Pearson chi-square tests were used to estimate differences in categorical data; predictors of palliative care referral/use were determined by logistic regression analysis. Results: 10,441 pts were included. The median age was 66 years. Regarding place of origin: 15.5% of pts were from Mexico, 8% from South/Central America, 7% from Cuba, 6% from Puerto Rico, 2.4% from the Dominican Republic and 57.6% were no-otherwise specified. When all Hispanic pts were included, 3.5% received surgery, 45% radiation and 52.9% chemotherapy. Overall, 2.2% of pts received a referral for palliative pain management +/- other palliative therapies. When divided by place of origin, Dominican pts had the highest percentage of pain management referrals at 5.5% (p<0.01) followed by Puerto Rican patients (2.4%). On the other hand, only 1.3% of pts from South/Central America were referred to pain management. In multivariate analysis, Dominican Republic origin (OR: 3.30, 95%CI: 1.69-6.44, p<0.01), bone metastasis (OR: 1.98, 95%CI: 1.17-3.3, p<0.01) and a Charlson comorbidity index ≥2 (OR: 2.07, 95%CI: 1.11-3.85, p<0.02) were significant predictors of receiving a pain management referral. We observed an increased number of pain management referrals over time with 1.4% of Hispanic patients getting a referral in 2004 vs. 2.9% in 2013 (p<0.02). Conclusions: We observed that only a small percentage of Hispanic pts with metastatic NSCLC cancer are receiving referral for palliative care/pain management. Several cultural beliefs and barriers may play a role in these findings. Providers should offer early referrals to pain management/palliative care to all patients with metastatic NSCLC independent of their race or ethnicity.

Citation Format: Narjust Duma, Urshila Durani, Julian Molina, Timothy J. Moynihan. Utilization of palliative therapies among Hispanics with stage IV non-small cell lung 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 1641.
Abstract 1707: Tumor treating fields exert cellular and immunologic effects
Authors: Wong Eric T. , Timmons Joshua , Swanson Kenneth D.
Published: August 2018

While there is clear clinical evidence to support the therapeutic efficacy of low dose alternating electric fields (TTFields) in treating glioblastoma, their intracellular targets and mechanism of action remains poorly defined. Historically, TTFields have been thought to operate by inducing extensive plasma membrane blebbing during the entry into anaphase resulting in aberrant mitotic exit and cell death. However, we have found that cells exposed to TTFields exhibited increased granularity and evidence of endoplasmic reticulum stress and genotoxic stress suggesting other mechanisms to explain their clinical efficacy. Cells exposed to TTFields exhibited reductions in levels of culture media acidification and analysis of intracellular metabolism showed evidence for an increase in mitochondrial respiration and glutaminolysis pathway. Our previous analysis of data from the pivotal phase III EF-11 clinical trial showed that increased corticosteroid use was strongly correlated with poor outcomes in TTFields-treated patients, possibly by suppressing immune effector function required for to drive tumor regression. TTFields drives the cell surface expression of immune stimulatory stress marker proteins calreticulin, and the secretion of the Alarmin/DAMP protein, HMGB1 which are together suggest that TTFields can stimulate immunogenic cell death. Co-culture of bone marrow derived macrophages with TTFields-treated CT26 cells resulted in the up-regulation of cell surface activation markers in the macrophage population that was blocked by a monoclonal antibody directed against HMGB1. Further, supernatants from these co-cultures contained increased levels of pro-inflammatory cytokines and chemokines and a reduction of anti-inflammatory cytokines associated with the presence of the TTFields-treated cells relative to co-cultures containing naïve tumor cells. Further, in vivo, engrafted Lewis lung carcinoma tumors exhibited increased levels of granzyme positive cells following TTFields treatment. Together, these data suggest that TTFields affect cancer cells during interphase and this insult leads to alterations in cancer cell metabolism and increased tumor cell immunogenicity and thus act to drive increased immune recognition and tumor rejection. In patients, these effects are likely to be opposed by the immune suppressive functions within the tumor microenvironment and corticosteroid use. Therefore, this model of TTFields action may provide a therapeutically rational base to devise improved TTFields treatment strategies from.

Citation Format: Eric T. Wong, Joshua Timmons, Kenneth D. Swanson. Tumor treating fields exert cellular and immunologic effects [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 1707.
Abstract 1710: DKN-01, a therapeutic DKK1 neutralizing antibody, has immune modulatory activity in nonclinical tumor models
Authors: Haas Michael , Heath Heidi , Wu Yinyuan , Zhang Xinjun , Sirard Cynthia , He Xi , Newman Walter , Kagey Michael
Published: August 2018

Wnt signaling is a fundamental pathway that is dysregulated in oncology. The Wnt signaling modulator DKK1 is expressed in a variety of tumor types and elevated levels frequently correlate with poor survival. DKK1 promotes tumor growth by stimulating proliferation, metastasis, and angiogenesis, and has been implicated in contributing to an immune suppressive tumor microenvironment. DKN-01 is a humanized monoclonal therapeutic antibody that binds DKK1 with high affinity and selectivity. It is currently being evaluated clinically as a monotherapy and in combination in a variety of solid tumors. Here we describe further characterization of the mechanism of action of DKN-01 and demonstrate immune mediated anti-tumor activity in nonclinical models. A murine version of DKN-01 (mDKN-01) has efficacy in a syngeneic melanoma B16 tumor model. However, mDKN-01 is unable to impede B16 tumor growth in NSG immunodeficient mice, indicating that a functioning immune system is required for antibody activity. Furthermore, preliminary data suggest that mDKN-01 is targeting a myeloid derived suppressor cell population in the tumor microenvironment. These data support an immune mediated mechanism of action of DKN-01 and provide a rationale for clinical development in combination with immunotherapy agents. The first clinical study evaluating DKN-01 in combination with pembrolizumab has initiated enrollment in patients with relapse/refractory esophagogastric malignancies.

Citation Format: Michael Haas, Heidi Heath, Yinyuan Wu, Xinjun Zhang, Cynthia Sirard, Xi He, Walter Newman, Michael Kagey. DKN-01, a therapeutic DKK1 neutralizing antibody, has immune modulatory activity in nonclinical tumor models [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 1710.
Abstract 1728: Nonalcoholic steatohepatitis (NASH) impairs treatment of intrahepatic metastases with CD4+ T cell dependent RNA vaccine
Authors: Heinrich Bernd , Brown Zachary J. , Mathias Vormehr , Fu Qiong , Ma Chi , Yu Su Jong , Sahin Ugur , Greten Tim F.
Published: August 2018

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disorder in Western industrialized countries. NAFLD along with its advanced form non-alcoholic steatohepatitis (NASH) are becoming an increasing risk factor for the development of cirrhosis and subsequently for hepatocellular carcinoma (HCC). We showed a selective CD4+ T cell loss in mice fed with methionine-choline deficient (MCD) diet, a model to induce NASH (Ma et al. Nature 2016). This selective loss of CD4 T cells may not only lead to immune escape by tumor cells but also lessen the effectiveness of immunotherapy. Kreiter et al. created a RNA vaccine from B16 melanoma cells encoding the neo-epitope M30, which is presented by MHC class II and recognized by CD4+ T cells. The vaccine showed therapeutic immune response in mouse models of subcutaneous B16-tumors and lung metastases (Kreiter et al. Nature 2015). Here we present an in vivo study of M30 RNA vaccine in a mouse model of B16 melanoma liver metastasis induced by intrahepatic injection. Mice were separated into groups and fed regular chow or MCD diet. B16F10-GFP-Luc melanoma cells were intrahepatically injected and mice were treated with M30 RNA or irrelevant RNA as control via tail vein injection. Intrahepatic tumor growth was monitored by bioluminescence imaging over the course of treatment. Mice were sacrificed and immunomonitoring of tumor surrounding liver tissue and tumor infiltrating lymphocytes (TIL) was performed. Mice treated with M30 RNA vaccine showed reduced tumor growth of intrahepatic metastasis compared to irrelevant RNA. Mice fed MCD diet could not control tumor growth either receiving M30 RNA vaccine treatment or irrelevant RNA. This impaired function of the treatment was related to a loss of CD4+ T cells in the NASH liver and a more immunosuppressive immune cell phenotype in the tumor environment.

This study indicates impaired efficacy of cancer immunotherapy due to fatty liver disease and subsequently changed immune response due to loss of CD4+ T cells as the main effector immune cell. As the M30 RNA vaccine reduced tumor growth in non-fatty liver, this data might be considered when planning future immunotherapy treatment strategies for comorbid patients with fatty liver disease as CD4+ T cell based treatment strategies might be impaired in patients with NASH.

Citation Format: Bernd Heinrich, Zachary J. Brown, Vormehr Mathias, Qiong Fu, Chi Ma, Su Jong Yu, Ugur Sahin, Tim F. Greten. Nonalcoholic steatohepatitis (NASH) impairs treatment of intrahepatic metastases with CD4+ T cell dependent RNA vaccine [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 1728.
Abstract 1733: Wnt antagonists synergize with immune checkpoint inhibitors to enhance anti-tumor responses
Authors: Ross Jenny , Hoey Timothy , Kapoun Ann , Lewicki John , Gurney Austin , Murriel Christopher L.
Published: August 2018

Aberrant Wnt signaling through overexpression or activating mutations in Wnt pathway proteins is responsible for the initiation and progression of numerous cancers. While enhanced Wnt signaling has been shown to play a major role in cancer stem cell biology, more recent studies have implicated Wnt in the development of resistance to anti-tumor immune responses. Here, we show that in various syngeneic murine tumor models, targeting Wnt signaling using the Fzd receptor monoclonal antagonist antibody, OMP-18R5 (vantictumab) or the pan-Wnt decoy receptor Fc fusion protein OMP-Fzd8-Fc (ipafricept) in combination with immune checkpoint inhibitors anti-CTLA-4 or anti-PD1 induce synergistic anti-tumor responses leading to decreased tumor volume and increased infiltration of activated CD8+ T cells into the tumor microenvironment. In addition, we show that combined Wnt and immune checkpoint inhibition decrease regulatory T cells (Tregs), enhance cytotoxic T cell activity and increase antigen presentation by APCs. More importantly, we demonstrate that anti-PD1 and the Wnt antagonists decrease immune suppressive myeloid cell populations, which may enhance therapeutic efficacy and anti-tumor responses. Therefore, these results suggest that co-targeting Wnt and immune checkpoint proteins may provide valuable opportunities for novel combination strategies for immunotherapeutic clinical development.

Citation Format: Jenny Ross, Timothy Hoey, Ann Kapoun, John Lewicki, Austin Gurney, Christopher L. Murriel. Wnt antagonists synergize with immune checkpoint inhibitors to enhance anti-tumor responses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1733.
Abstract 1784: IL-7R targeting therapy for immunoregulation and overcoming steroid resistance in cancer and autoimmune disease
Authors: Yasunaga Masahiro , Manabe Shino , Matsumura Yasuhiro
Published: August 2018

The occurrence of autoimmune reactions caused by immune checkpoint blockade in the treatment of cancer indicates the importance of the cross-disciplinary study of malignancy and autoimmune disease. Meanwhile, although steroids have been commonly used for the treatment of malignancies and immune diseases, steroid resistance is a serious prognosis factor and remains an unsolved problem. IL-7R signaling, which physiologically regulates lymphocyte growth and survival, including antigen-responsive T lymphocyte selection, has been implicated in the development of malignancies and autoimmune diseases. However, the biological significance of IL-7R-signaling in steroid treatment is poorly understood. Here, we identified the relationship between unique IL-7R-signaling and steroid-resistance in lymphoid malignancy and demonstrated the presence of steroid-resistant IL-7R-positive lymphocytes in a mouse bone marrow and spleen or in a mouse model of autoimmune arthritis following steroid treatment. We further showed that an anti-IL-7R-antibody conjugated with SN-38 (A7R-ADC-SN-38) has strong anti-tumor effects against both parent and steroid-resistant malignant cells. Although A7R-ADC-SN-38 efficiently eliminated IL-7R-positive cells, IL-7R-negative mature lymphocytes were preserved. Furthermore, inflammation in the mouse autoimmune arthritis model was suppressed to a greater extent by A7R-ADC conjugated to MMAE than by A7R-ADC-SN-38. Strong and specific elimination of enhanced IL-7R-positive cells, a common pathogenesis of both lymphoid malignancy and autoimmune disease, might prevent the development of malignancy or autoimmune disease in high-risk patients. Thus, the use of A7R-ADC may be a promising strategy for the immunoregulation of both malignancy and autoimmune disease and may serve as a new option to steroid therapy. Thus, A7R-ADC may be a promising strategy to treat malignancies and autoimmune diseases and may serve as a novel alternative to steroid therapy. Thus, A7R-ADC may be a promising strategy to treat malignancies and autoimmune diseases and may serve as a novel alternative to steroid therapy. We have evaluated the effectiveness of A7R-ADC in the treatment of other autoimmune or inflammatory diseases involving IL-7R signaling in a preclinical setting for general use. In addition, IL-7R metastatic solid tumors which acquired Il-7R-dependent homing ability of lymphocytes to be spread into many organs may also be promising therapeutic targets of A7R-ADC. We are proceeding the study to advance A7R-ADC for clinical use in both cancer and autoimmune disease

Citation Format: Masahiro Yasunaga, Shino Manabe, Yasuhiro Matsumura. IL-7R targeting therapy for immunoregulation and overcoming steroid resistance in cancer and autoimmune 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 1784.