bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3846: Targeting epigenetic dysregulation in isocitrate dehydrogenase mutant glioblastoma
Authors: Sears Thomas K. , Datta Sandipan , Cortopassi Gino , Angelastro James , Woolard Kevin
Published: August 2019

Glioblastoma (GBM) is an incurable form of brain cancer with a median survival time (MdST) of ~15 months after treatment with chemoradiotherapy. Identification of a CpG Island Methylator Phenotype (CIMP) subtype of GBM (G-CIMP), represents a significant clinical discovery, as these patients have an enhanced survival, with a MdST of 3 years. G-CIMP is characterized by a mutation in isocitrate dehydrogenase 1 or 2 (IDH1/2), which results in production of the oncometabolite 2-hydroxglutarate, an inhibitor of α-ketoglutarate-dependent demethylases. This results in aberrant DNA methylation, transcriptional repression, and may drive tumorigenesis. Here, we present data showing that G-CIMP is significantly more sensitive in vitro to inhibitors of the two arms of epigenetic regulation of transcription: the transcriptional activation arm and the transcriptional repression arm. Drug targets include the Bromodomain and Extraterminal (BET) and Histone Deacetylase (HDAC) proteins, involved in epigenetic transcriptional activation of oncogenes and repression of tumor suppressors, respectively. G-CIMP cells show a profound loss of cell viability at submicromolar concentrations using the small molecule inhibitors JQ1 and Panobinostat, which target BET and HDAC proteins, respectively. Western blot analysis indicates that BET inhibition elicits preferential loss of histone phosphorylation and acetylation in G-CIMP, notably serine 10 of Histone 3 and lysine 27 of Histone 3 (H3K27Ac), respectively. Both epigenetic marks are associated with positively regulating transcription. H3K27Ac is a superenhancer with known functions in activating oncogene transcription. These data ultimately suggest that G-CIMP tumor cells are reliant on established epigenetic transcriptional regulation to maintain cell viability. The global methylation status of these tumors may make them particularly sensitive to pharmacologic disruption of these epigenetic pathways. These studies provide a strong foundation for future preclinical work evaluating the prospective treatment of G-CIMP with combinatorial therapy using BET and/or HDAC inhibitors.

Citation Format: Thomas K. Sears, Sandipan Datta, Gino Cortopassi, James Angelastro, Kevin Woolard. Targeting epigenetic dysregulation in isocitrate dehydrogenase mutant glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3846.
Abstract 3847: Knockout of DNMT1 using CRISPR gene-editing technology confers resistance to DNMT inhibitors in human breast cancer cells
Authors: Laranjeira Angelo B. , Huang Erich , Rubinstein Larry , Nguyen Dat , Yang Sherry X.
Published: August 2019

DNA methyltransferase (DNMT) 1 plays an important role for DNA replication and cell proliferation, and it is implicated in the maintenance and propagation of DNA methylation patterns. Targeting DNMT represents a promising approach for epigenetic therapy in cancer. To better elucidate the function of DNMT1 on the treatment effect of DNMT inhibitors in cancer cells derived from human solid tumors, we used clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated system (Cas9) to edit DNMT1 gene in MCF-7 breast carcinoma cells. The co-transfection of the DNMT1 target sequence that directs to exon 1 of the gene in pCas-guide vector and a donor DNA vector effectively knocked down DNMT1 protein in MCF-7 cells as detected by Western blot. After 96h of drug exposure, IC50s of azacitidine (5-azacytidine) and decitabine (5-aza-2’-deoxycytidine) were all higher than 10 µM in DNMT1 knockout (DNMT1-/-) cells assessed by MTT; in contrast, IC50s were 1.44 µM and 10 µM in parental (DNMT1+/+) cells. As for the cellular survival in the presence of drugs, a remarkable increase in the colony formation was observed in DNMT1-/- cells compared to DNMT1+/+ cells. The annexin-V/propidium iodide test by flow cytometry provided evidence of lower percentages of necroptosis in the DNMT1-/- cells than DNMT1+/+ cells when the cells were exposed to these inhibitors for 48 hours at 5 µM (7.12 ± 5.24 vs. 39.0 ± 2.65 by azacitidine, p = 4.11 × 10-5, and 5.77 ± 4.19 vs. 20.0 ± 6.66 by decitabine, p = 4.11 × 10-5); in addition, there were large fractions of viable cells in the DNMT1-/- cells versus DNMT1+/+ cells (85.86 ± 6.39 vs. 56.86 ± 4.00 for azacitidine treatment, p = 4.11 × 10-5 and 87.4 ± 5.56 vs. 76.2 ± 9.36 for decitabine, p = 5.60 × 10-3). The findings demonstrate that knockout of DNMT1 using CRISPR/Cas9 method leads to an increased resistance to azacitidine and decitabine, in corroboration with our previous data in DNMT1 knockout HCT116 colorectal cancer cells. Therefore, DNMT1 is critical to antitumor activity of DNMT inhibitors in human solid tumor cell lines.

Citation Format: Angelo B. Laranjeira, Erich Huang, Larry Rubinstein, Dat Nguyen, Sherry X. Yang. Knockout of DNMT1 using CRISPR gene-editing technology confers resistance to DNMT inhibitors in human breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3847.
Abstract 3873: CHOP10/TRB3/Akt signaling regulates ER stress apoptosis in colon cancer cells treated with prostamide-J
Authors: Albassam Hussam , Ladin Daniel A. , Dross Rukiyah Van
Published: August 2019

The endoplasmic reticulum (ER) is a cellular organelle that is primarily responsible for oxidative protein folding. When the protein folding load in cells exceeds the protein folding capacity, ER stress occurs. The ER stress pathway is a prominent regulator of cancer cell death and as a result, ER stress inducers are being exploited pharmacologically. Cytotoxic ER stress is typically regulated by the transcription factor, C/EBP homologous protein 10 (CHOP10). Transcriptional products of CHOP10 include pro-apoptotic genes, such as tribbles-related protein 3 (TRB3), death receptor-5 (DR5), and ER oxidoreductase 1α (ERO1α). Our previous data showed that apoptosis mediated by 15deoxy, Δ12,14 prostamide J2 (15dPMJ2) occurred in an ER stress-dependent manner. However, the signaling pathway that regulates 15dPMJ2 mediated ER stress apoptosis has not been identified. Therefore, the goal of this study is to determine the role of CHOP10 and its transcriptional targets in ER stress apoptosis that is induced by 15dPMJ2 in colon cancer cells. According to our data, 15dPMJ2 was 3-fold more effective in inducing apoptosis in the human colon cancer cell line, HCT116, compared to the non-tumorigenic colon cell line, FHC. The induction of apoptosis in HCT116 cells occurred coincident with a significant increase in CHOP10 protein expression. In addition, blockade of the ER stress pathway with 4-phenylbuterate (PBA) or salubrinal prevented apoptosis indicating that cell death is reliant upon ER stress. To determine the role of CHOP10 in this process, CRISPR/Cas9 CHOP10 knockout HCT116 cells (CHOP10-KO-HCT116) were generated. As anticipated, 15dPMJ2 increased CHOP10 expression in wt-HCT116 cells but not in CHOP10-KO-HCT116 cells. Furthermore, 15dPMJ2 increased the expression of ERO1α, DR5, TRB3, and it induced apoptosis in wt-HCT116 cells, but not in CHOP10-KO cells. Interestingly, the induction of TRB3, but not DR5 or ERO1α, was completely inhibited in cells devoid of CHOP10 expression. Therefore, the activity of protein kinase B (PKB)/Akt, a known TRB3 target, was investigated. CHOP10 stimulation by 15dPMJ2 inactivated Akt in wt-HCT116 cells, but not in CHOP10-KO cells. These findings suggest the importance of CHOP10, TRB3, and Akt in the control of the ER stress-mediated apoptosis in response to 15dPMJ2 treatment. Thus, 15dPMJ2 is a potential chemotherapeutic agent that inhibits PKB/Akt survival signaling by upregulating the CHOP10/TRB3 pathway to prevent colon cancer growth.

Citation Format: Hussam Albassam, Daniel A. Ladin, Rukiyah Van Dross. CHOP10/TRB3/Akt signaling regulates ER stress apoptosis in colon cancer cells treated with prostamide-J [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3873.
Abstract 3885: Evaluation of pharmacokinetics of proxalutamide, a novel androgen receptor antagonist, in treatment for mCRPC patients via CTC enumeration and AR biomarker analysis
Authors: Chu Lincy , Zhang Phoebe , Anderson Amanda , Landers Mark , Wang Yipeng , Zhou Karl
Published: August 2019

Introduction: Proxalutamide (code name: GT-0918) is a novel androgen receptor (AR) blocker and has shown efficacy in the treatment of castration resistant prostate cancer. Proxalutamide binds to AR and inhibits androgen-induced receptor activation. A Phase 1/2 clinical trial (ClinicalTrials.gov Identifier: NCT02826772) was conducted to identify dose-limiting toxicities (DLTs) and to assess safety, tolerability, and PK of GT0918 in pts with mCRPC who have progressed on standard of care and experimental therapies in the United States. To better understand patient responses and pharmacokinetics of GT0918, we sought to examine CTC enumeration, AR-N term expression, and AR-V7 nuclear expression using Epic CTC platform for patients treated with GT0918.

Methods: A total of 18 metastatic castrate resistant prostate cancer (mCRPC) patients were recruited under either dose escalation or expansion studies and blood samples were collected at 3 time points: C1D1, C3D1, and C6D1/EOS. Patients with histologically confirmed mCRPC who had progressed after both hormonal therapy (abiraterone or enzalutamide) and chemotherapy (e.g., docetaxel) were eligible. Dosages of 300, 400, and 500 mg were evaluated in this study. CTCs were detected using the Epic Sciences platform and assessed for full length AR status using an AR N-terminus specific antibody and for nuclear localized AR-V7 truncation. AR-V7 nuclear localization was confirmed by trained technician.

Results: 18/18 (100%) of patients had detectable CTCs, with 12/18 (67%) patients having AR-N term+ CTCs. 7/12 (58%) of AR-N term+ patients were AR-V7 positive. Reduction of CTC/mL, AR+ CTC/mL and % of AR+ CTC in follow up draws were observed in the whole cohort, with 500mg dose group showing more reduction than others. Sample accrual and patient follow up is ongoing and the correlation of CTC, AR, and AR-V7 status with the clinical outcomes will be investigated once the data becomes mature.

Conclusions: In this clinical trial, we evaluated the pharmokinetic effects of GT0918 on CTC enumeration and Androgen Receptor CTC status. GT0918 might serve as a potential alternative for late stage mCRPC patients who have developed resistance to both hormone and chemotherapy treatments. The role of CTC as PK marker or patient selection device is ongoing.

Citation Format: Lincy Chu, Phoebe Zhang, Amanda Anderson, Mark Landers, Yipeng Wang, Karl Zhou. Evaluation of pharmacokinetics of proxalutamide, a novel androgen receptor antagonist, in treatment for mCRPC patients via CTC enumeration and AR biomarker analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3885.
Abstract 3896: Distinct pharmacokinetics, tissue distribution and CNS penetration of ABI-009 (nab-Sirolimus)
Authors: Hou Shihe , Schmid Anita , Desai Neil
Published: August 2019

Background: Activation of the mTOR signaling pathway is frequently observed in multiple types of cancer. The poor solubility and low oral bioavailability of the mTOR inhibitor sirolimus limit its development as an anticancer therapy. ABI-009 (nab-sirolimus) is an injectable nanoparticle form of human albumin-bound sirolimus developed with a proprietary nanoparticle albumin-bound (nab®) technology. Currently, numerous phase 1 and 2 clinical studies are ongoing with ABI-009, including a registrational phase 2 study for the treatment of malignant perivascular epithelioid cell carcinoma (PEComa), and various oncology (bladder cancer, soft-tissue sarcomas, neuroendocrine tumors, colorectal cancer, glioblastoma, and various childhood cancers) as well as in non-oncology indications (pulmonary arterial hypertension (PAH), pediatric epilepsy, and mitochondrial diseases). Several nonclinical studies were conducted to evaluate pharmacokinetics, tissue distribution and in particular, CNS penetration of ABI-009.

Methods: Rats were intravenously (IV) administered with a single dose of ABI-009 at 1.7, 9.5, and 17 mg/kg. Blood and organs were collected at 2, 8, 24, 72, and 120 hrs to analyze for sirolimus concentrations.

Results: There is a generally linear dose response with sirolimus concentrations in blood, heart, lung, liver, and pancreas following a single dose of IV ABI-009. Sirolimus concentrations in blood and well-perfused organs had high peaks at earlier time points but dropped quickly with time, with the highest concentrations observed in lung. In contrast, sirolimus concentrations in brain rose slowly at first, but maintained at a steady level over time. After 5 days, sirolimus level in the brain was similar to other organs, suggesting substantial and prolonged drug distribution to the brain with ABI-009. Organ/blood ratios of most organs increased with time, with the brain/blood ratios increasing more significantly over time. Higher initial dose of ABI-009 resulted in increased brain/blood ratios.

Conclusions: ABI-009 administered IV demonstrated a distinct PK profile compared with oral mTOR inhibitors. The PK of ABI-009 is characterized by higher Cmax and AUC, and rapid tissue distribution. Combined with efficient tumor penetration observed in a xenograft study, results of this study support the potential use of ABI-009 for the treatment of cancers in different organ sites, including lung, brain, liver, and pancreas. These findings also warrant further clinical studies in non-oncology indications including PAH and disorders involving the CNS.

Citation Format: Shihe Hou, Anita Schmid, Neil Desai. Distinct pharmacokinetics, tissue distribution and CNS penetration of ABI-009 (nab-Sirolimus) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3896.
Abstract 3906: PK-PD modelling of an anti-CTLA-4 antibody on immune checkpoint humanized mice
Authors: Lee Madeline , Xiang Jie , Gan Tian , Shen Yuelei , Guo Chaoshe
Published: August 2019

Cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4; also known as CD152) is expressed on the surface of T cells, where it primarily suppresses the early stages of T cell activation. In preclinical studies, blockade of CTLA-4 led to an increase in T-cell proliferation. Anti-CTLA-4 monoclonal antibodies (mAbs) have been shown to be an effective approach for tumor immunotherapy. Preclinical pharmacokinetic (PK) and pharmacodynamic (PD) characterization of these antibodies is essential for designing first-in human trials.

PK prediction is especially challenging for monoclonal antibodies attributed to target-mediated drug disposition (TMDD). We generated a humanized B-hCTLA-4 mouse model, in which exon 2 of the murine CTLA-4 gene was replaced with its human counterpart. In homozygous mice, only human protein expression can be detected, while mouse CTLA-4 was knocked out. Using B-hCTLA-4 mice, we developed a mAb PK/PD model to characterize the anti-tumor effects of hCTLA-4 antibodies.

MC38 cancer cells were inoculated into both C57BL/6 wild type and humanized CTLA-4 animals. After administering different antibody concentrations (ranging from 3.0, 1.0, 0.3, 0.1mg/kg), serum samples from each animal were taken at specific time points for PK/PD analysis. An NCA approach was used to determine serum concentrations of mAb in mice. The levels of 13 cytokines (IL-23, IL-1α, IFN-r, TNF-a, IL-6 etc.) were quantified using LEGENDplex bead-based immunoassays. The PK half-life was 50~100h and the cytokine concentration ranged from 0-2000pg/ml depending on the dose used. The Tumor Growth Inhibition (TGI) value was also evaluated as a PD effect in the MC38/B-hCTLA-4 model. The TGI value reached nearly 100% when the dose was above 0.3mg/kg. The PK/PD assays showed that the anti hCTLA-4 mAb tested has a dose-dependent tumor inhibition effect in hCTLA-4 mice. Results from TMDD model data showed that the humanized mice reached QuasiSteady State faster than wild type mice, indicating that the humanized mice are an appropriate TMDD model. In conclusion, humanized B-hCTLA-4 mice are a promising PK/PD model for CTLA-4 mAb preclinical trials.

Citation Format: Madeline Lee, Jie Xiang, Tian Gan, Yuelei Shen, Chaoshe Guo. PK-PD modelling of an anti-CTLA-4 antibody on immune checkpoint humanized mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3906.
Abstract 3971: MEK inhibitors limit inflammatory cytokine production and modulate the immune response in the setting of Cholangiocarcinoma.
Authors: Ruggieri Amanda N. , Farren Matthew R. , Yarchoan Mark , Azad Nilofer S. , Dennison Lauren , El-Reyes Bassel , Lesinski Gregory B.
Published: August 2019

Cholangiocarcinoma (CC) is a rare but aggressive cancer of the bile ducts with a five-year survival rate of only 2% in patients with metastatic disease. MAP kinase signaling is important in the pathogenesis of CC and serves as a key regulator of cell proliferation and survival. Our data indicate this pathway is constitutively active in several CC cell lines and accompanied by production of immunomodulatory cytokines including IL-6, MCP-1 and GM-CSF. Cobimetinib is a potent and selective inhibitor of MEK that has been utilized clinically in patients with advanced CC. Although MEK inhibitors (MEKi) have been studied in a variety of solid tumors, the mechanisms by which they act upon CC cells are not completely defined. These agents have modest single agent activity in CC, and their impact in combination with immunotherapy is under active investigation. We hypothesized that MEKi can modulate cytokine and chemokine expression from CC tumors, thereby complementing immunotherapy in this aggressive disease. Using a novel panel of human CC cell lines, we demonstrated a variable impact of cobimetinib on in vitro cell proliferation, with a reduction in viability no greater than 35%. However, MEKi reproducibly limited cytokine (GM-CSF and IL-1β) and chemokine (MIP-1α) production from human CC cell lines in vitro. The ability of cobimetinib to limit MAPK signal transduction in these cells was confirmed via immunoblot. These data complement prior published observations by Ebert et al.in 2016 indicating that single agent MEKi is sufficient to elicit T cell infiltration into tumors. We have completed enrollment of a Phase II clinical trial (NCT03201458) evaluating the efficacy of cobimetinib in combination with the PD-L1 inhibitor, atezolizumab. An extensive series of correlative studies are underway in peripheral blood and tumor biopsies to examine the impact of cobimetinib on modulating cytokine and chemokine signatures in the context of PD-L1 targeted therapy. These data will provide new insight into the impact of MEK inhibitors as a complement to immunotherapy in a disease that is refractory to most conventional therapies.

Citation Format: Amanda N. Ruggieri, Matthew R. Farren, Mark Yarchoan, Nilofer S. Azad, Lauren Dennison, Bassel El-Reyes, Gregory B. Lesinski. MEK inhibitors limit inflammatory cytokine production and modulate the immune response in the setting of Cholangiocarcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3971.
Abstract 3980: Molecular profiling of cell-free DNA and RNA in the blood of patients with non-small cell lung cancer
Authors: Reese Jordan , Jackson Leisa , Mellert Hestia S. , Pestano Gary
Published: August 2019

Lung cancer is the leading cause of cancer-related deaths in the United States with Non-Small Cell Lung Cancer (NSCLC) being the most commonly diagnosed subtype. However, up to 30% of advanced NSCLC patients are not eligible for tissue biopsy. As a result, liquid biopsies are becoming increasingly utilized in clinical testing as they are non-invasive and have an overall decreased risk to patients. This approach also addresses other challenges associated with tissue-based profiling, including tumor heterogeneity and low yield of quality nucleic acid for the identification of actionable targets of treatment. In this study, cell-free total nucleic acid (cfTNA) was isolated from donor patient plasma samples collected and shipped at ambient temperatures in blood collection tubes to the Biodesix CAP/CLIA laboratory in Boulder, CO. cfTNA was profiled with a targeted cancer NGS (next generation sequencing) panel, using the Ion Torrent GeneStudio S5 Plus System. Variant analyses were conducted using a threshold of ≥0.3% percent variant allele frequency to assess concordance in the patient donor specimens. A high level of concordance (R2=0.99) was observed between inter-laboratory/inter-instrument NGS runs using 6 clinical samples. In the 0.1% single nucleotide variant (SNV) positive control sample which encompasses 23 hotspots, there was slightly lower concordance (R2=0.90) due to low variant allele frequency (0.06-0.3%). Validation studies are in progress and include RNA fusions and additional variants present in blood from patients diagnosed with NSCLC.

Citation Format: Jordan Reese, Leisa Jackson, Hestia S. Mellert, Gary Pestano. Molecular profiling of cell-free DNA and RNA in the blood of patients with non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3980.
Abstract 4000: Development of a patient navigation training program for the Caribbean context
Authors: Ashing Kimlin T. , Badal KImberly
Published: August 2019

Introduction

For the Caribbean context, a patient navigator (PN) is one who is responsible for coordinating and streamlining care in a complex cancer care continuum by providing support in physical, mental and emotional challenges; educating and empowering patients in their journey; tracking patient medical records electronically and addressing barriers to care. As a first step to introducing this role to the Caribbean, a comprehensive training program for new navigators was developed and conducted.

Methods

A multi-disciplinary steering committee consisting of a behavioral scientist, two oncology registered nurses and educators, a clinical psychologist, two cancer survivors, a cancer researcher, a physician and an experienced oncology nurse navigator was formed in Trinidad and Tobago. The steering committee had these objectives: (i) develop a comprehensive list of PN core competencies; (ii) determine PN skill requirements; (iii) develop and execute a training curriculum that met the PN core competencies.

Results

Two categories of navigators and requisite skill requirements were developed for each (Table 1). Three skill domains were defined as patient navigator skills, research skills and professional skills. Each domain was then divided into specific competencies which translated into 11 curriculum topics. Candidates who met the skill requirements filled a form-based application, provide a curriculum vitae and completed 0.5hr scenario-based interview. A 5-day, 30 contact hour patient navigation training program was successfully conducted with candidates from 4 Caribbean territories. Results of the pre- and post- test assessment as well as the training evaluation will be reported in the presentation.

Conclusion

A productive international collaboration between City of Hope an NCI designated Comprehensive Cancer Center and CCRI a civil society cancer organization successfully developed and conducted a comprehensive program to train patient navigators for the Caribbean context.

Table 1:Skill requirements for oncology nurse navigators and lay navigatorsOncology Nurse NavigatorLay NavigatorPrimary Skill RequirementsOncology-trained Registered Nurse. Registered Nurse with 2 years clinical experience in OncologyCancer survivor. Care giverAlternative Skill Requirements SkillsRetired medical personnel. Any Registered NurseAny person with interest, holding a minimum Bachelor degree in a related area of expertise such as counselling pharmacy, psychology, social work etc.

Citation Format: Kimlin T. Ashing, KImberly Badal. Development of a patient navigation training program for the Caribbean context [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4000.
Abstract 4007: Decipher the myth between progression-free survival and overall survival in HER-2 positive metastatic nreast cancer: Anti-HER2 antibody as the constant winner—A hypothesis-driven meta-regression analysis
Authors: Chen I-Chun , Hu Fu-Chiang , Lin Ching-Hung , Lu Yen-Shen
Published: August 2019

Purpose: Traditionally, the predictive value of progression free survival (PFS) hazard ratio (HR) on overall survival (OS) HR in metastatic breast cancer (MBC) was low. We observed that when trials were designed as adding on an anti-HER2 antibody, either trastuzumab or pertuzumab, to the control treatment, the OS increment is usually greater than the PFS increment. We aim to investigate the interaction of increment of median PFS and median OS in HER-2 positive MBC stratified by drug difference patterns between treatment arms using trial-level information.

Methods: All randomized phase II or III trials of systematic therapy specifically for HER-2 positive MBC with available OS information were included after a systematic literature review. Treatment arms with shorter PFS were defined as control arm in the analysis. The correlation and interaction of HR for PFS and OS as well as the absolute increment for median PFS and OS were evaluated by fixed-effect or random-effect meta-regression meta-analysis. Drug difference between two treatment arms were specified as a categorical variable in the analysis.

Results: A total of 28 trials with 10928 patients published between January 1999 and December 2017 were included in the final analysis. The correlation of median PFS HR (0.73, 95% C.I.= 0.68-078) and median OS HR (0.82, 95% C.I.= 0.77-0.87) was modest as reported by other investigators. However, when the drug difference between treatment arms was anti-HER2 antibody, the absolute increment in median OS is 2 fold of the absolute increment in median PFS (p = 0.0005), showing a linear correlation. This linear correlation was not observed when the drug difference between treatments was non-anti-HER2 antibody. Anti-HER2 antibody as drug difference would translate the absolute increment of median PFS into absolute increment of median OS, suggesting a good predictive value of median PFS on median OS.

Conclusion: Anti-HER2 antibody as the drug difference between treatment arms provides consistently longer OS improvement than PFS improvement in HER-2 positive MBCs.

Citation Format: I-Chun Chen, Fu-Chiang Hu, Ching-Hung Lin, Yen-Shen Lu. Decipher the myth between progression-free survival and overall survival in HER-2 positive metastatic nreast cancer: Anti-HER2 antibody as the constant winner—A hypothesis-driven meta-regression analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4007.
Abstract 4018: Pan-cancer predictions of drug sensitivity based on protein-coding and non-coding RNA biomarkers
Authors: Lloyd John P. , Merrill Nathan , Lachacz Eric , Li Jun Z. , Merajver Sofia , Soellner Matthew
Published: August 2019

Molecular characteristics that accurately forecast tumor response to drug therapies represent an important target for precision cancer treatment. However, it is not known whether tumor drug response can be predicted in a tissue-agnostic manner or if predictions must be established within historically-defined cancer types and subtypes. To address this question, we utilized public datasets to test whether multi-omics biomarkers in 346 tumor cell lines representing 17 cancer types can predict response to five small molecule therapies (2 MEK, 2 PI3K, and 1 FGFR inhibitors). The pool of potential biomarkers tested included 51,268 total RNA expression levels and DNA variants. We identify a panel of 45 gene expression levels capable of accurately predicting response to MEK inhibitors (AUC-ROC >0.90), indicating that tumor response to small molecule drugs can be predicted regardless of cancer type. We found that RNA expression levels, notably among non-coding sequences, were most important for predictions. Experimental validation of the 45-gene panel is demonstrated based on predicted and observed MEK inhibitor sensitivity in 12 cell lines from 5 cancer types without previously known drug sensitivities. Successful pan-cancer predictions of drug response in cancer cell lines represents a critical step toward truly personalized treatment in real time, based on the characteristics of individual tumors.

Citation Format: John P. Lloyd, Nathan Merrill, Eric Lachacz, Jun Z. Li, Sofia Merajver, Matthew Soellner. Pan-cancer predictions of drug sensitivity based on protein-coding and non-coding RNA biomarkers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4018.
Abstract 4060: Discovery and screening of protein biomarkers with the FirePlex Technology Platform
Authors: Perea Amy , Neuner Russell , Heinrich Bianca , Doran Graeme , Austin Wayne , Rafferty Conor , Camilleri Matt , Tackett Michael , To Long , Atabakhsh Elnaz , Murray James , Pregibon Daniel
Published: August 2019

In patients and animal models, molecular biomarkers are used as indicators of normal and pathogenic processes. In drug discovery and screening pipelines, molecular biomarkers are used to assess the mechanism of action, efficacy, and toxicity of lead compounds. To address the need for rapid and sensitive biomarker quantitation, we have developed the FirePlex® Technology Platform. Utilizing patented hydrogel particles and a three-region encoding design, FirePlex assays allow for true, in-well multiplexing, providing flexible and customizable quantification of miRNA and protein analytes. To facilitate biomarker discovery studies, we offer our standard-throughput, flow cytometry-based assays which enable quantitation of up to 75 miRNA or protein analytes per sample, from only 20 µl of input. These assays demonstrate 5 logs of dynamic range and offer highly sensitive quantitation of analytes in serum, plasma, cell culture supernatant, urine, and CSF without the need for sample processing or RNA isolation. For drug discovery and screening studies, we offer our high-throughput FirePlex (FirePlex®-HT) Immunoassays for quantitation of up to 10 protein analytes per sample from only 6.25 µl biofluid input, in 384-well plate format. FirePlex-HT assays provide 3-4 logs dynamic range, demonstrate 1-100 pg/ml sensitivity, and have been validated in serum, plasma, and cell culture supernatant. The two-step workflow, no-wash assay format, and readout on high-content imagers limit hands-on time and are amenable to automation, thus making FirePlex-HT ideally suited for high-throughput screening studies. In addition, here we introduce our high-throughput miRNA assays for screening miRNA biomarkers in 96-well or 38-4well plate format, with readout on high-content imagers. Here we present data from miRNA and protein profiling studies using the FirePlex platform, and introduce the simplified workflow of the FirePlex-HT® immunoassays with data demonstrating the performance for quantifying key cytokines in multiplex, in biological samples. Together, this novel combination of multiplexed, high-sensitivity assays and bioinformatics tools enables rapid quantitation of protein biomarker signatures in biofluid specimens.

Citation Format: Amy Perea, Russell Neuner, Bianca Heinrich, Graeme Doran, Wayne Austin, Conor Rafferty, Matt Camilleri, Michael Tackett, Long To, Elnaz Atabakhsh, James Murray, Daniel Pregibon. Discovery and screening of protein biomarkers with the FirePlex Technology Platform [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4060.
Abstract 4067: PD-L1 expression, CD8 cells and MHC-class-1 Beta-2-microglobulin expression in advanced non-small lung cancer
Authors: Hijmering-Kappelle Lucie , Hiltermann Jeroen , Hiddinga Birgitta , Wekken Anthonie van der , Hart Nils 't , Groen Harry , Timens Wim
Published: August 2019

Introduction: PD-L1 expression has been approved as predictive biomarker for immune checkpoint inhibitors (ICI) in non-small cell lung carcinoma (NSCLC). In case of lack of PD-L1 expression in tumor biopsies, 8-10% of patients will respond to ICI. However, in case of > 50% PD-L1 tumor expression half of patients show no response. Tumor immune escape phenotypes are characterized by loss of MHC-class-I and a lower grade of CD8 T-cell infiltration, despite upregulation of PD-L1 expression. At least one of the four phenotypes of MHC-class-I and PD-L1 co-expression is considered responsible for non-responsiveness. We investigated the frequency of PD-L1, MHC-class-I β2-microglobulin (β-2M) co-expression and presence of CD8 cells in advanced NSCLC.

Methods: Analysis was performed on formalin fixed, paraffin embedded (FFPE) transbronchial or transthoracic tumor biopsies of 27 patients with advanced NSCLC. Immunohistochemistry was performed using Ventana Benchmark Ultra immunostainer. PD-L1 was detected using Ventana PD-L1 (SP263) Assay (CE IVD), CD8 by Ventana CONFIRM anti-CD8 (SP57) antibody and MHC-class I β2-M by Agilent-Dako polyclonal rabbit anti-human beta-2-Microglobulin. PDL1 expression was scored as percentage positive tumor cells according to the manufacturers guideline, β2-M was scored as positive or negative in tumor cells and CD8 cells as low (+), intermediate (++) or high (+++) numbers in tumor or peritumoral stroma.

Results: In 27 patients IHC staining was performed. PDL1 expression was scored as <1%, 1-49% and ≥50% in 17, 3, and 7 patients, respectively. PD-L1 positive (>1%) patients had positive β-2M in 10 of 10 cases. PD-L1 negative tumors showed presence of β-2M in 10 of 17 cases. Seven out of 27 cases (26%) were β-2M negative; all of them were PD-L negative cases. Low CD8 score was seen in 7 patients and 2 of these patients have a PD-L1 expression >1% and positive β-2M.

Conclusion: In this ongoing study one quarter of advanced NSCLC patients had no tumor MHC-class-1 β-2M expression. In our cohort β-2M negative phenotype was associated with lack of PD-L1 tumor expression.

Citation Format: Lucie Hijmering-Kappelle, Jeroen Hiltermann, Birgitta Hiddinga, Anthonie van der Wekken, Nils 't Hart, Harry Groen, Wim Timens. PD-L1 expression, CD8 cells and MHC-class-1 Beta-2-microglobulin expression in advanced non-small lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4067.
Abstract 4069: Development of PSB205, a bifunctional MabPair product that targets PD-1 and CTLA-4
Authors: Fanslow William C. , Liu Zhi , Hu Zhonghua , Liu Hua , Shen Min , Peng Yufeng , Domeier Cristina , Treiber David , Schoner Ron , Yan Wei
Published: August 2019

Here we describe a novel platform that enables the production of two full length IgG molecules from a single production cell line. This technology was achieved using a molecular engineering approach to precisely control the cognate pairing of antibody heavy chains and light chains during the assembly of two antibodies in the same cell line. This technology platform, which has been designated as MabPair, can be applied for the development of therapeutic antibody products that contain a mixture of two different antibodies. The antibody cocktail is produced by the same cell line in a predefined ratio and can be manufactured using a conventional antibody production process. When addressing multiple targets, MabPair products can offer significant advantages and flexibility over a bispecific antibody. MabPair technology represents a novel approach for developing antibody combination products. This approach is exemplified by the development of PSB205, our lead MabPair product candidate. PSB205 targets two immune checkpoint pathways, PD-1 and CTLA-4. The development of PSB205, as a potential anti-cancer immunotherapeutic, is discussed.

Citation Format: William C. Fanslow, Zhi Liu, Zhonghua Hu, Hua Liu, Min Shen, Yufeng Peng, Cristina Domeier, David Treiber, Ron Schoner, Wei Yan. Development of PSB205, a bifunctional MabPair product that targets PD-1 and CTLA-4 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4069.
Abstract 4079: EVT801: a selective VEGFR3 inhibitor with the potential for combination with immune-checkpoint therapies, preclinical evidences and plans for first-in-human evaluation
Authors: Fons Pierre , Esquerre Michael , Paillasse Michael , Visentin Virgile , Dol Frederique , Meneyrol Jerome , Badet Gaelle , Cogo Eric , Vidaud Lionel , Alam Antoine , Blanc Isabelle , Bono Francoise , Lisztwan Joanna , Poublanc Muriel , Filleron Thomas , Hunneyball Ian , Delord Jean-Pierre , Whittaker Mark
Published: August 2019

We have identified a highly selective VEGFR3 inhibitor drug candidate, which strongly inhibits angiogenesis without inducing hypoxia, reputed as one of the main causes of cancer-associated immunosuppression. Combination of EVT801 and Immune Checkpoint Therapy (ICT) could be synergistic as hypoxia-induced-immunosuppression should be avoided. We have demonstrated that EVT801 is a narrow spectrum inhibitor of the VEGFR3 tyrosine kinase with residual activity against VEGFR2 and TAK1 and with an activity on VEGFRs different from Fruquitinib and Lenvatinib. We then showed that EVT801 inhibited human endothelial cell proliferation in vitro and tumor angiogenesis on ex-vivo mouse ring aortic assay. EVT801 was active in vivo in the RIP1-Tag2 mouse model during the angiogenic switch. In comparison to sorafenib, EVT801 in 2 different tumors mouse model decreased tumor development without inducing increase of hypoxia which is in favor to a sustained blood vessel tumor normalization. In orthotopic 4T1 mammary carcinoma, we demonstrated that EVT801 in combination with PD1 mAb was significantly superior than single agent treatment and a decrease of lung metastasis spreading was observed. We observed that decrease of MDSCs in blood in response to EVT801 was correlated with decrease in tumor weight. By IHC analysis, we showed that treatment with EVT801 increases CD8+ T-cells infiltration inside the tumor. Taken together, these results indicated that EVT801 represents an innovative anti-angiogenic drug for cancer immunotherapy which may improve the frequency of response to ICT. Clinical trial design including patient stratification and biomarkers of activity has been proposed in order to be ready for first-in-human evaluation by mid-2019.

Citation Format: Pierre Fons, Michael Esquerre, Michael Paillasse, Virgile Visentin, Frederique Dol, Jerome Meneyrol, Gaelle Badet, Eric Cogo, Lionel Vidaud, Antoine Alam, Isabelle Blanc, Francoise Bono, Joanna Lisztwan, Muriel Poublanc, Thomas Filleron, Ian Hunneyball, Jean-Pierre Delord, Mark Whittaker. EVT801: a selective VEGFR3 inhibitor with the potential for combination with immune-checkpoint therapies, preclinical evidences and plans for first-in-human evaluation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4079.
Abstract 4098: A heavy chain only antibody against CTLA4 with outstanding preclinical efficacy and safety profile
Authors: Liu George , Gan Xin , He Yun , Zhao Jiuqiao , Duan Huayan , Rong Yiping
Published: August 2019

Anti-CTLA-4 antibodies are one of the only three types of immune checkpoint inhibitors (together with anti-PD-1 and anti-PD-L1 antibodies) with proven monotherapy value in cancer therapy. Despite demonstrated efficacy, their broad application in monotherapies and combinational therapies are hampered by the safety profiles. Evidence in animal models suggests that efficacy of anti-CTLA-4 antibodies is at least partially due to depletion of regulatory T cells (Treg) via ADCC function, whereas clinically adverse events are positively correlated with systemic exposure.

Here we embarked to develop the next generation anti-CTLA-4 antibody with better efficacy and safety profile. Fully human Heavy Chain only antibody (HCAb) 4003-2 was generated using the Harbour HCAb transgenic mouse platform. 4003-2 specifically binds to CTLA-4 and blocks its binding to B7.1/B7.2. It was optimized to have enhanced ADCC function that affords superior ability to deplete Treg cells both in vitro and in vivo. 4003-2 showed in murine tumor models significantly more potent anti-tumor activity than other CTLA4 antibodies, at least partly driven by substantially enhanced depletion of intra-tumoral Treg cells. In addition, due to its shorter serum half-life, 4003-2 has less systemic drug exposure in vivo at efficacious doses, suggesting potentially improvement of safety profile in clinical applications.

The augmented efficacy and safety profile of 4003-2 present it as an excellent candidate for the development of next generation anti-CTLA4 therapy.

Citation Format: George Liu, Xin Gan, Yun He, Jiuqiao Zhao, Huayan Duan, Yiping Rong. A heavy chain only antibody against CTLA4 with outstanding preclinical efficacy and safety profile [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4098.
Abstract 41: A novel high-throughput microfluidic drug screening platform using pancreatic ductal adenocarcinoma derived organoids
Authors: Kramer Bart , Paassen Wijnand van , Haan Luuk de , Lanz Henriette , Joore Jos
Published: August 2019

Pancreatic cancer is one of the deadliest tumors due to the limited treatment options and late diagnosis. Here, we describe a novel high throughput drug screening platform combining a microfluidic based 3D-culture plate, and the recently described pancreatic ductal adenocarcinoma (PDAC) derived organoids. The microfluidic plate is a high throughput microfluidic 3D cell culture platform, supporting physiologically relevant models with a minimal requirement of cell material and enabling a wide range of flow and co-culture options (e.g. with blood vessels). Organoids were derived from human PDAC xenografts and seeded in the microfluidic plate. The low amount of tissue material required (4000 cells per chip) and the high number of replicates on one plate (n=96 on a standard microtiter format plate) renders the microfluidic plate an efficient and cost-effective platform for drug screening and toxicity assays on complex, 3D models. Organoids were exposed to various chemotherapeutic drugs for 72 hours. The viability of the organoids before and after drug treatment is monitored with standard viability assays and subsequently used to generate dose response curves. In conclusion, we showed that the microfluidic plate can be used for high throughput drug screening assays and toxicity screening, and demonstrated its compatibility with human pancreatic PDAC derived organoids.

Citation Format: Bart Kramer, Wijnand van Paassen, Luuk de Haan, Henriette Lanz, Jos Joore. A novel high-throughput microfluidic drug screening platform using pancreatic ductal adenocarcinoma derived organoids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 41.
Abstract 4109: Functional profiling of 17,000 open reading frames identifies regulators of PDL1 expression in HNSCC
Authors: Mann Jacqueline , Devenport Samantha , Kulkarni Aditi , Hoesli Rebecca , Foltin Susan , Michmerhuizen Nicole , Nesvizhskii Alexey , Brenner Chad
Published: August 2019

The interaction of Programmed Death Ligand 1 (PD-L1) with the PD-1 receptor serves as an immune checkpoint, dampening anti-tumor immunity. While immunotherapies targeting this pathway (Pembrolizumab and Nivolumab), were approved for use in recurrent and metastatic head and neck squamous cell carcinoma (HNSCC) in 2016, overall response rates are low and few biomarkers have been identified to differentiate responders. We expect a more detailed understanding of PD-L1 checkpoint regulation in HNSCC to provide insight toward addressing these deficits. Thus, we developed a high- throughput screening protocol to discover signals modulating PD-L1 expression. We have employed a lentiviral open reading frame (ORF) library for overexpression of over 14,000 different genes in a pooled format. UM-SCC-49 cells transduced with this library were stained for cell surface PD-L1 and sorted by flow cytometry to select cells with enhanced PD-L1 expression. Sequencing of the selected sub-population was performed to determine ORFs enriched over an unsorted pool. To validate a role for individual target genes in modulating PD-L1 expression, monoclonal populations were expanded from the sorted pool and evaluated for PD-L1 expression. We confirmed increased PD-L1 expression in 7 of these cell lines over wild-type and LacZ overexpressing controls via western blotting and flow cytometry. Furthermore, we selected 5 ORFs of interest overrepresented in the sorted pool for further validation using stably expressed V5 tagged constructs. Target gene expression was confirmed by western blot, and enhanced cell surface PD-L1 expression was validated via flow cytometry for 4/5 cell lines. Thus, we provide evidence for successful identification of signals regulating PD-L1 using a novel high-throughput overexpression screen. Future experiments will aim to clarify the mechanism of PD-L1 induction in response to the signals identified here, and may ultimately provide a more thorough understanding of genetic factors modulating immunosuppression and response to immunotherapy in HNSCC patients.

Citation Format: Jacqueline Mann, Samantha Devenport, Aditi Kulkarni, Rebecca Hoesli, Susan Foltin, Nicole Michmerhuizen, Alexey Nesvizhskii, Chad Brenner. Functional profiling of 17,000 open reading frames identifies regulators of PDL1 expression in HNSCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4109.