bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 684: Gastrointestinal/liver-targeted TLR7 agonist for treatment of colorectal and liver cancers
Authors: Miller Andrew T. , Rodrigo Evelyn , Corpuz Manny , Plouffe David , Wu Tom Y.-H.
Published: September 2020

Anti-PD1/L1 has become the backbone of immune therapy for many cancer types. However, the majority of patients do not respond due to a myriad of mechanisms affecting the tumor microenvironment, including low tumor mutational burden and low immune cell infiltrate. Innate immune agonists can potentially address both issues by increasing tumor antigen presentation and tumor microenvironment inflammation, thereby turning cold tumors hot. As clinical proof-of-concept, many intratumoral TLR/STING agonists have shown promising anti-tumor responses as single agents and in combination with checkpoint inhibitors; however, successful clinical applications have been limited to cutaneous-accessible tumor types. APR003 is an orally-administered GI/liver-targeted small molecule TLR7 agonist designed for the treatment of visceral colorectal and liver cancers. Studies in mice and monkeys demonstrate robust Type-1 Interferon pathway activation with good tolerability. APR003 is efficacious in several syngeneic orthotopic models of liver and colon cancer, both as single agent and in combination with anti-PDL1. Mechanistic studies show enhancement of CD103+ dendritic cells in tumor draining lymph nodes and tumor antigen-specific T cells in the tumor microenvironment. Pre-clinical pharmacology data will be presented.

Citation Format: Andrew T. Miller, Evelyn Rodrigo, Manny Corpuz, David Plouffe, Tom Y.-H. Wu. Gastrointestinal/liver-targeted TLR7 agonist for treatment of colorectal and liver cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 684.
Abstract 694: PAWI-2 overcomes tumor stemness and drug resistance in pancreatic cancer stem cells
Authors: Cheng Jiongjia , Cashman John , Gomez-Galeno Jorge
Published: September 2020

Today, pancreatic cancer (PC) remains a major health problem in the US and soon will be the second most common cause of mortality due to cancer. However, most of the front-line PC chemotherapies cause serious side effects and a majority of patients with PC are often resistant to clinical therapies. The fact that cancer stem cells (CSCs) become enriched after anti-cancer therapy implicates CSCs as key contributors to tumor dormancy, metastasis, and relapse in PC. Given the important role of human pancreatic cancer stem cells (hPCSCs) in PC, development of a novel treatment strategy that targets hPCSCs or their extrinsic and intrinsic regulators could be of great clinical utility to treat PC. Herein, we used a highly validated hPCSCs model (FGβ3 cells) to test a novel compound (PAWI-2) to target CSCs. In this hPCSC model, integrin αvβ3 expression was shown to be a marker/functional contributor to CSC progression and drug resistance attributed to its ability to trigger anchorage-independent cell survival and tumor metastasis. Specifically, integrin αvβ3 recruits KRAS and RalB to tumor cell plasma membranes to activate NF-κB signaling that triggers dysregulated KRAS-RalB-NF-κB pathways. This was shown to be a pharmacological target to reverse CSC-like properties or re-sensitize drug resistance (e.g., EGFR inhibitors, erlotinib) of established FGβ3 tumors. Compared to parental FG cells, PAWI-2 showed greater potency to inhibit cell viability and self-renewal capacity of FGβ3 cells. PAWI-2 inhibited dysregulated integrin β3-KRAS-RalB-NF-κB signaling independent of KRAS and Ral. This is clinically relevant because >90% of KRAS is activated by mutations in PC and RAS or Ral inhibitors have not proven effective clinically. PAWI-2 targeted downstream of KRAS signaling and was negatively regulated by other feedback mechanisms. This was further shown by genetic knockdown of key regulator and co-treatment of specific inhibitors. PAWI-2 overcomes erlotinib resistance in FGβ3 cells with greater potency than bortezomib. In the proposed mechanism of PAWI-2 action, key regulators link the inhibition of KRAS signaling and cell cycle arrest (G2/M). The great utility and pharmacological potency of PAWI-2 in FGβ3 cells (that possess stem-like properties) compared to FG cells provide a basis for further development. PAWI-2 as an efficient therapeutic to reverse tumor stemness and resensitize CSC tumors to drug inhibition.

This work was supported by Inception Award from California Institute for Regenerative Medicine (CIRM) (DISC1-10583; J.R. Cashman) and by funds from the Human BioMolecular Research Institute.

Citation Format: Jiongjia Cheng, John Cashman, Jorge Gomez-Galeno. PAWI-2 overcomes tumor stemness and drug resistance in pancreatic cancer stem cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 694.
Abstract 722: Urine for noninvasive liquid biopsy for germline and somatic mutations
Authors: Vowles James V. , Kim Amy K. , Hamilton James P. , Lin Selena Y. , Shieh Fwu-Shan , Luu Harry , Villafana Gabrielle , Hu Chi-Tan , Su Ying-Hsiu
Published: September 2020

Circulating tumor DNA (ctDNA) from blood and peripheral blood mononuclear cells (PBMCs) are used to determine comprehensive cancer genetics and germline genomics for precision medicine. To evaluate the use of urine samples as a noninvasive alternative to blood samples, we performed a comprehensive characterization of urine DNA as an alternative to PBMC DNA for germline genomics.

Whole genome sequencing (WGS) was performed in PBMC and total urine DNA in six normal subjects to compare the quality and comprehensiveness of the genomic data. There was no significant difference between the sequencing data obtained from PBMC and urine DNA upon comparing the variant calling, percent reads passing Phred score Q30 (p>0.05, paired t-test), and coverage of human genome. Similar to plasma cfDNA, mononucleosomal-sized DNA was the most predominant species present in urine cfDNA. Samples from three hepatocellular carcinoma (HCC) patients were further analyzed for insert sizes by NGS, which demonstrated predominantly mononucleosomal-sized DNA fragments, with a series of peaks occurring with 10-bp periodicity, in both urine and plasma cfDNA. With shallow WGS, the genome coverage overlap was 53-61%, and by increasing the depth of coverage the overlap increased from 60% to 74%. Interestingly, 8-10% of the genome covered in plasma DNA was not detected in urine DNA, and 4-8% of the genome covered in urine DNA was not covered in plasma DNA.

Next, we compared the detectability of three HCC-associated genetic mutations in the matched urine and plasma DNA obtained from 76 HCC patients including mutations at TP53 codon 249 (TP53 249T), CTNNB1 exon 3 regions 32-37 (CTNNB1 32-37), and hTERT promoter region position 124 (hTERT 124). We observed higher levels of the TP53 mutation, similar levels of CTNNB1 mutation, and lower levels of the TERT mutation in urine cfDNA compared to plasma ctDNA. This suggests a potential for urine as a potential noninvasive source for ctDNA analysis, and a combination of both urine and plasma ctDNA may increase the overall sensitivity of ctDNA detection. In conclusion, our data suggest that (1) total urine DNA can replace PBMC DNA for providing comprehensive genomic sequencing data and (2) urine can complement blood for liver cancer liquid biopsy, precision medicine, and potential applications in other cancers.

Citation Format: James V. Vowles, Amy K. Kim, James P. Hamilton, Selena Y. Lin, Fwu-Shan Shieh, Harry Luu, Gabrielle Villafana, Chi-Tan Hu, Ying-Hsiu Su. Urine for noninvasive liquid biopsy for germline and somatic mutations [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 722.
Abstract 728: Early assessment of treatment effect in small cell lung cancer (SCLC) via ctDNA analysis
Authors: Jiang John , Ju Christine , Woestmann Corinna , Balasubramanyam Aarthi , Xi Liu , Yaung Stephanie J. , Gattam Sandeep , Hinzmann Bernd , Thomas Michael , Lasitschka Felix , Meister Michael , Schneider Marc , Herth Felix , Muley Thomas , Wehnl Birgit , Palma John
Published: September 2020

INTRODUCTION:

Quantifying circulating tumor DNA (ctDNA) is an emerging method to non-invasively assess treatment effect for solid tumors. A ctDNA-based method for disease monitoring for small cell lung cancer (SCLC) would be beneficial to disease management. By employing plasma taken during early treatment cycles and NGS, we tested whether early response assessed by ctDNA level could predict treatment effect.

METHODS:

Using a 197-gene NGS assay, the AVENIO ctDNA Surveillance Kit (for Research Use Only, not for use in diagnostic procedures), ctDNA levels were assessed in post-treatment plasma samples based on variants identified at baseline. Mutant allele concentration or mutant molecules per milliliter-of-plasma (MMPM) was utilized to quantify ctDNA over all variants of all sequenced genomic regions.

Samples collected from an observational German Lung Cancer Multi-Marker Study were analyzed retrospectively. In a cohort of 69 stage IV SCLC subjects, the association of survival with ctDNA-based monitoring classifier was evaluated in the first available post-treatment plasma sample after starting chemotherapy (median number of days after start of treatment = 25) by Kaplan-Meier methods and Cox proportional hazards model.

RESULTS:

The analysis demonstrated that subjects with mean MMPM less than the lower quartile (14.3) had longer progression free survival (PFS) compared to that of subjects with mean MMPM greater than or equal to the lower quartile (log-rank P = 0.0095; HR [95% CI] = 0.48 [0.27, 0.84]). The same classifier was applied for overall survival analysis, and subjects with mean MMPM less than the lower quartile had longer overall survival (OS) compared to that of subjects with mean MMPM greater than or equal to the lower quartile (log-rank P = 0.0095; HR [95% CI] = 0.46 [0.26, 0.84]).

CONCLUSIONS:

Changes in ctDNA levels in response to treatment may prove to be a valuable way of identifying subjects that either respond or fail to respond to therapy earlier than current standard of care methods such as computed tomography (CT) scan. Hypotheses will be validated in a separate cohort. Future prospective studies to confirm these results are needed.

Citation Format: John Jiang, Christine Ju, Corinna Woestmann, Aarthi Balasubramanyam, Liu Xi, Stephanie J. Yaung, Sandeep Gattam, Bernd Hinzmann, Michael Thomas, Felix Lasitschka, Michael Meister, Marc Schneider, Felix Herth, Thomas Muley, Birgit Wehnl, John Palma. Early assessment of treatment effect in small cell lung cancer (SCLC) via ctDNA analysis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 728.
Abstract 773: Tumor-derived Extracellular Vesicles (EVs) expressing TGFb as potential biomarkers for anti-TGFb antibody activity and drug activity in liquid biopsy
Authors: Nunes Manoel , Bernard Camille , Muzard Gaelle , Dos-Santos-Bele Wilson , Pollard Jack , Protopopov Alexei , Dib Colette
Published: September 2020

The field of liquid biopsies is of enormous interest in cancer using a noninvasive process. There are currently three major approaches: Circulating Cell Tumors (CTCs), circulating cell free DNA (cfDNA) and Extracellular Vesicles (EVs) such as exosomes, microvesicles and apoptotic bodies. The EVs are cell-derived small membrane vesicles secreted by cells that convey biological messages, either by surface-to-surface interaction or by shuttling bioactive molecules to a recipient cell's cytoplasm. The EVs released by cells harbor the cargos of their original cells and could be a good tool to follow drug activity.

We are developing anti-TGFβ antibody SAR439459 for the treatment of cancer (NCT03192345), and in this vitro study we explore the effect of anti-TGFβ antibody in EVs carrying TGFβ. The cargo of EVs were analyzed by an Elisa test for both latent and active free TGFβ and by miRNA expression.

Cell lines were selected based on their expression of TGFβ (A549, DU45, PC3, MCF7 and Caco2), treated for 72h and compared with respective untreated controls. The EVs were isolated from the supernatant and purified. Nanoparticle Tracking Analysis was used to quantify and determine size distribution of EVs. The expression of active free and latent TGFβ was done using Elisa tests. TGFβ antibody-coated magnetic beads were used to capture EVs, and miRNA expression sequencing was done using the Illumina NextSeq.

Anti-TGFβ treatment reduced notably the expression of latent TGFβ in the supernatant of cultured tumor cells; the active free TGFβ was very low expressed or not detected in the supernatants. EVs express both latent and active free TGFβ; the anti-TGFβ antibody treatment significantly reduced the active free TGFβ and altered miRNA expression in EVs. Finally, using TGFβ Antibody-coated magnetic beads, we demonstrate that intact EVs express TGFβ at their surface.

In conclusion, these results suggest that EVs express TGFβ at their surface and carry the active free TGFβ. Finally, the expression of active free TGFβ in EVs is decreased with anti-TGFβ antibody, suggesting that it might be a biomarker for monitoring anti-TGFβ antibody activity in patients by liquid biopsies.

Citation Format: Manoel Nunes, Camille Bernard, Gaelle Muzard, Wilson Dos-Santos-Bele, Jack Pollard, Alexei Protopopov, Colette Dib. Tumor-derived Extracellular Vesicles (EVs) expressing TGFb as potential biomarkers for anti-TGFb antibody activity and drug activity in liquid biopsy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 773.
Abstract 807: Predictive biomarkers for Bevacizumab activity in recurrent glioblastoma: A single institution study
Authors: Dragan Marcin , Carli Matthew , Malkin Mark , Yazbeck Victor
Published: September 2020

Glioblastoma Multiforme (GBM) is an aggressive type of astrocytoma and the most common malignant brain tumor in adults. Bevacizumab is a recombinant monoclonal antibody that targets VEGF-A. VEGF is regulated by the hypoxia-inducible-factor (HIF-1α) pathway, with the tumor suppressor gene TP53 as one of the key regulating factors. Our study examines the relevance of various genetic mutations of the HIF-1α pathway and their predictive significance in patients diagnosed with recurrent GBM and treated with bevacizumab. A total of 41 patients diagnosed with recurrent GBM and treated with Bevacizumab at Virginia Commonwealth University from January 1990 through November 2018 were included in our study. Our study cohort consists of 56.1% males and 43.9% females, with an average age of 59.9 (SD 12.1), and 68.3% were Caucasian. The majority (90%) of the cohort were classified as de novo cases of GBM. The overall survival (OS) was 172.5 days (95% CI: 122.0, 218.5), with a minimum of 11 days and maximum of 904 days measured from the date of the first bevacizumab treatment to the date of death. The majority of patients (70.7%) responded to treatment, with 61% exhibiting a partial response and 9.8% exhibiting a complete response. The median first response to treatment (FRT) was 34 days (95% CI: 21, 40), with a minimum of 2 days and maximum of 76. All patients died during the follow-up period. Survival analyses for OS, along with FRT, were both performed with Kaplan-Meier curves generated individually. We have examined the clinical characteristics of our study cohort and are currently examining the genetic characteristics of the tumors in our cohort. At the time of the conference we will have updated genomic and radiographic data in addition to the current detailed clinical data.

Citation Format: Marcin Dragan, Matthew Carli, Mark Malkin, Victor Yazbeck. Predictive biomarkers for Bevacizumab activity in recurrent glioblastoma: A single institution study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 807.
Abstract 869: Leveraging a novel analysis pipeline for outcomes predictions from routine MRIs
Authors: Vadmal Vachan , Waite Kristin , Barnholtz-Sloan Jill S.
Published: September 2020

There is a desperate need for approaches that allow us to use routinely gathered clinical and imaging data to make outcomes predictions for patients. The acquisition of MRI images forms a standard part of clinical care for cancer patients, especially for malignant brain tumor patients. As these digital MRI scans are performed regularly, the associated digital MRI data also grows and can form the basis for longitudinal assessment of disease and prediction of clinical outcomes. However, standard modalities are coupled with non-standard modalities in most cases (some of which is institution specific), making it difficult to organize and standardize these images for analysis. In addition, for a rare cancer such as malignant brain tumors, multi-institutional collaborations are necessary in order to have appropriate power for analyses, thereby complicating the issues around organization and standardization of images for analysis. In addition, there are likely to be discrepancies among data formats intra-institutionally. To address these shortcomings and to expedite the research process, we developed a general digital MRI analysis pipeline that is able to organize messy data, automatically preprocess, segment, extract features, and produce results that are ready for statistical analysis and discovery. Such a pipeline with modular segments for major stages in the process is beneficial to investigators who are analyzing MRI data and hope to save time from the tedium of organization and data management. With a focus on efficiency, extensibility, and reproducibility, the tools that form this pipeline also aim to increase the accessibility of complex imaging analysis to a wider audience by leveraging artificial intelligence. While pipelines exist in the literature, most are not focused on clinical MRI images of brain tumors and quickly become deprecated as software dependencies change, resulting in outdated and potentially buggy software. Our pipeline implements the latest Python version using object-oriented principles, employing PEP 8 style, and is optimized to run on modern hardware thus ensuring extensibility. The pipeline itself runs intuitively via the command line interface (CLI) that requires minimal input parameters to perform its subtasks but will have the option of accepting other parameters. We showcase features of this new MRI analysis pipeline, using malignant brain tumors as an exemplar, given their disproportionate contribution to cancer morbidity and mortality.

Citation Format: Vachan Vadmal, Kristin Waite, Jill S. Barnholtz-Sloan. Leveraging a novel analysis pipeline for outcomes predictions from routine MRIs [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 869.
Abstract 908: BRAF inhibition and nanoparticle-delivered cytokine therapy for melanoma: A novel rational combined approach
Authors: Romano Gabriele , Liang Roger , Francesca Paradiso , Miller John , Taraballi Francesca , Costello James , Kwong Lawrence
Published: September 2020

Although the advent of BRAF inhibitors plus MEK inhibitors has revolutionized BRAF-mutant melanoma therapy, most patients relapse within 16 months due to the persistence of minimal residual disease (MRD), a key obstacle in cancer therapy. In our inducible genetically engineered mouse model (iBIP), doxycycline withdrawal results in BRAFV600E extinction causing tumors to shrink, but not completely disappear, achieving a status of MRD. Time-course microarray analysis revealed a set of immune hallmarks with acute and strong initial activation after BRAFV600E extinction, then a decrease through to MRD, suggesting that the MRD might be immune suppressive/evasive.

Systems biology analysis pinpointed the family of interferon inducible chemokines CXCL9/10/11 as central players in the orchestration of the process: CXCL9/10/11 are strongly induced within 8 hours of BRAFV600E extinction, but dissipate just prior to MRD, paralleling the more general immune signature. Data obtained in human samples and in other immunocompetent mouse models also show both a strong CXCL9/10/11 induction after BRAF inhibition and an immune evasive/suppressive microenvironment after eventual tumor relapse. Our preliminary data indicates resident macrophages as the main population responsible for CXCL9/10/11 production.. These data led us to hypothesize that sustaining CXCL9/10/11 expression might support superior tumor immune infiltration and activation to neutralize or eradicate the MRD.

In a pilot study, we have observed significant tumor rejection in vivo with combined BRAF extinction plus intratumoral recombinant CXCL9 (rCXCL9) therapy in immunocompetent mice, which suggests that CXCL9 can therapeutically convert immunologically “cold” MRD back to “hot”. In order to improve the pharmacokinetics of cytokine therapy, we are currently developing a nanoparticle-based delivery that extends stability and half-life of rCXLC9 in vitro, with in vivo experiments as the next step. In this work, we utilized a confluence of in silico and in vivo data to guide the rational identification of a molecularly-driven cancer treatment based on immune drivers with predicted molecular synergy.

Citation Format: Gabriele Romano, Roger Liang, Paradiso Francesca, John Miller, Francesca Taraballi, James Costello, Lawrence Kwong. BRAF inhibition and nanoparticle-delivered cytokine therapy for melanoma: A novel rational combined approach [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 908.
Abstract 913: Defining melanoma patients unresponsive to single agent anti-PD-1 therapy but responsive to combination anti-PD-1 + anti-CTLA-4 therapy
Authors: Edwards Jarem J. , da Silva1 Inês Pires , Ferguson Angela , Johansson Peter , Conway Jordan , Attrill Grace , Saw Robyn P.M , Thompson John F. , Menzies Alexander M. , Palendira Umaimainthan , Long Georgina V. , Scolyer Richard A. , Wilmott James S.
Published: September 2020

Background: A proportion of patients that fail single agent anti-PD-1 therapy will subsequently receive and respond to combination anti-PD-1 and anti-CTLA-4 immunotherapy. The clinical and biological characteristics of these patients remain poorly defined and as such there are presently no reliable validated biomarkers to distinguish patients requiring the addition of anti-CTLA-4 in the context of anti-PD-1 therapy.

Clinical cohort and methods: We performed RNA sequencing, immunofluorescence-IHC, and multiparameter image-mass cytometry (IMC) on formalin-fixed paraffin embedded (FFPE) tumors at baseline and post anti-PD-1 therapy from n=15 stage IV melanoma patients who failed anti-PD-1 therapy and went on to receive combination immunotherapy (7 non-responders; 8 responders).

Results: Tumor pathological parameters including TIL and neutrophil densities, fibrosis, necrosis and mitotic rates identified were not different between responders and non-responders. While T-reg, cytotoxic CD8 and CD39+ resident CD8 T cells densities were not significantly different, the proportion of TCF7+ CD8 T cells was significantly higher at baseline (p=0.01) and in all tumor samples (p=0.007) in responders compared to non-responders. RNA differential gene expression analysis revealed higher expression of cancer testis antigens (CTAs) in responding patient tumors. Hierarchical clustering of differentially expressed genes separated responding patients from non-responding patients.

Conclusions: The proportion of TCF7+ CD8 T cells and the presence of melanoma cancer testis antigens may be a predictive biomarker of response to combination immunotherapy in patients failing anti-PD-1 monotherapy but requires further validation.

Citation Format: Jarem J. Edwards, Inês Pires da Silva1, Angela Ferguson, Peter Johansson, Jordan Conway, Grace Attrill, Robyn P.M Saw, John F. Thompson, Alexander M. Menzies, Umaimainthan Palendira, Georgina V. Long, Richard A. Scolyer, James S. Wilmott. Defining melanoma patients unresponsive to single agent anti-PD-1 therapy but responsive to combination anti-PD-1 + anti-CTLA-4 therapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 913.
Abstract 92: Increasing TTFields treatment efficacy by targeting G2 cell cycle checkpoint
Authors: Slangen Paul , van Geldorp Mariska , de Gooijer Mark , van Tellingen Olaf , Borst Gerben
Published: September 2020

Introduction; Tumor Treating Fields (TTFields) is a novel non-invasive anticancer treatment modality utilizing alternating electric fields. TTFields is FDA approved for glioblastoma patients after demonstrating a 5 months increase in overall survival, and for unresectable mesothelioma patients after the STELLAR trial showed an overall survival of 18 months without increasing the toxicity. While the effectiveness of TTFields is initially attributed to the effects of TTFields during cell division, studies are ongoing analysing its interphase effects and impact on the tumor (micro)environment. Our aim is to further exploit the working mechanism of TTFields by analysing its effect on the cell cycle and identify targets to increase its efficacy.

Material and Methods; To analyse the effect of TTFields on the cell cycle, A172 glioblastoma cells were synchronized in S-phase by double thymidine block. Six hours post-release, cells were subjected to TTFields treatment (200kHz; 4,5V/cm). Cell cycle analysis was performed by flow cytometry (PI, α-phospho-histone H3Ser10). Efficacy of combination strategies were tested in 3 different glioblastoma cells lines (A172, U251 and SNB-19). Efficacy was quantified by colony formation assay (CFA) testing the cell reproductive death after treatment (i.e. only viable cells after treatment are replated to analyse the colony forming capacity).

Results: TTFields treatment of synchronized A172 cells showed that TTFields causes an accumulation of cells in G2 phase and delayed entry into mitosis with less than 1% of the cells in mitosis 4 hours after TTFields exposure (versus 5% of mitotic cells in the control arm, p<0.001). This arrest can be abrogated by Wee1 inhibition (AZD1775) increasing the mitotic population to more than 35% at 4 hours after TTFields exposure (p<0.001). To test the efficacy of targeting the G2 checkpoint during TTFields treatment, cells were treated with TTFields and a Wee1 (AZD1775, PD0166285) or Chk1 (AZD7762) inhibitor for 72 hours and then replated for CFA. We observed an impressive synergistic effect between TTFields and any of these G2 cell cycle interfering drugs in all three cell lines (p<0.001).

Conclusion: The underlying mechanism of the G2 checkpoint activation and the synergistic effect of TTFields plus G2 checkpoint targeting agents is subject of ongoing research. By any means, the combination of TTFields and G2 checkpoint targeting agents causes a synergistic treatment effect and is a very promising strategy.

Citation Format: Paul Slangen, Mariska van Geldorp, Mark de Gooijer, Olaf van Tellingen, Gerben Borst. Increasing TTFields treatment efficacy by targeting G2 cell cycle checkpoint [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 92.
Abstract 94: Pla2g4a: A new cell cycle related gene in patients with non-M3/NPM1 wildtype acute myeloid leukemia
Authors: Bai Hansong , Ming Zeng
Published: September 2020

In this study, we aimed to explore and validate the prognostic value of PLA2G4A expression in patients with non-M3/NPM1 wildtype (WT) acute myeloid leukemia (AML) using two independent datasets. Data from the Cancer Genome Atlas-Acute Myeloid Leukemia (TCGA-LAML) and the Therapeutically Applicable Research to Generate Effective Treatments (TARGET)-AML were used to assess the prognostic value PLA2G4A in NPM1-WT AML cases. A single-cell RNA-seq dataset that included 96 AML cells from a recurrent AML case was used to check the correlation between PLA2G4A expression and the functional state of AML cells. Results showed that non-M3 AML cases had significantly increased PLA2G4A expression compared to normal peripheral blood samples. Multivariate analysis showed that high PLA2G4A expression was independently associated with shorter OS in 97 non-M3/NPM1-WT AML cases in TCGA-LAML (HR: 1.932, 95%CI: 1.092-3.419, p=0.024). The prognostic value was validated based on 128 non-M3/NPM1-WT AML cases in TARGET-AML (HR: 1.894, 95%CI: 1.065-3.369, p=0.030). Single-cell RNA-seq data suggested that PLA2G4A expression was positively correlated with cell cycle progression of AML cells. Therefore, PLA2G4A expression might serve as an independent prognostic marker in OS in patients with non-M3/NPM1 WT AML. Its upregulation might confer malignant phenotype of AML cells at least partly by promoting cell cycle progression. Future molecular studies are required to explore other molecular pathways involved.

Citation Format: Hansong Bai, Zeng Ming. Pla2g4a: A new cell cycle related gene in patients with non-M3/NPM1 wildtype acute myeloid leukemia [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 94.
Abstract 949: Anti-cancer activity by photoimmunotherapy is driven by adaptive immune responses and vaccinates the host against the tumor
Authors: De Magalhaes Filho C. Daniel , Hsu Michelle A. , Okamura Stephanie M. , Gitnick Dany , Solis Estela , Fong Jerry J. , Garcia-Guzman Miguel
Published: September 2020

INTRODUCTION: Photoimmunotherapy (PIT) is an investigational anti-cancer treatment platform utilizing cell-targeted antibodies conjugated to the IR700 (IRDye 700DX®) light-excitable dye. Upon illumination with non-thermal red light, target cells bound with antibody-conjugates undergo rapid necrosis. Previous work demonstrated that PIT induces features of immunogenic cell death of tumor cells and ignites an immune response against the tumor. In these preclinical studies, we investigated the extent to which the immune response contributes to the in vivo anti-cancer activity using syngeneic cancer models.

METHODS: PIT treatment was applied to a panel of mouse and human cancer cell lines targeted by their respective antigen-binding conjugate in vitro, and the release of damage-associated molecular patterns (DAMPs) was measured from the cell supernatant. To determine the contribution of the immune response to PIT anti-cancer activity, PIT treatment was applied to immunocompetent animals with antibody-mediated CD8 T cell depletion, or blockade of CD40-CD40L axis concurrent with tumor implant or PIT treatment. To determine whether the immunogenic properties of PIT treatment induce vaccinal effects, immunocompetent animals were inoculated with in vitro PIT-treated cancer cells, and then challenged with live tumor cells in the contralateral flank one week later.

RESULTS: Cancer cells treated with PIT released significant amounts of immunogenic cell death markers including DAMPs such as ATP and Annexin A1. The anti-cancer activity of PIT treatment in immunocompetent animals was inhibited when 1) pre-existing immunity was abrogated by blockade of the CD40-CD40L interaction at time of tumor implant, and 2) CD8 T cells were depleted from the animals. Applying CD40-CD40L blockade concurrent with PIT treatment partially abrogated anti-cancer activity. When animals were inoculated with cancer cells treated by PIT ex vivo, tumor rejection was achieved in 8 out of 9 animals when challenged with live tumor cells on the contralateral flank.

CONCLUSIONS: Cancer treatment by PIT induces necrotic and immunogenic cell death resulting in local and systemic immune response. These preclinical data indicate that adaptive immune responses induced by PIT treatment drive the anti-cancer effects and can also provide vaccinal effects due to the release of DAMPs and cancer antigens.

Citation Format: C. Daniel De Magalhaes Filho, Michelle A. Hsu, Stephanie M. Okamura, Dany Gitnick, Estela Solis, Jerry J. Fong, Miguel Garcia-Guzman. Anti-cancer activity by photoimmunotherapy is driven by adaptive immune responses and vaccinates the host against the tumor [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 949.
Abstract 953: Herpes simplex virus thymidine kinase/ganciclovir-mediated apoptotic tumor cells induce anti-tumor immunity
Authors: Umegaki Sho , Shirota Hidekazu , Ishioka Chikashi
Published: September 2020

Immune cells can recognize tumor antigen and elicit an adaptive immune response against tumor cells. It has been reported that apoptotic or necrotic death of tumor cells releases tumor antigen stimulating anti-tumor immunity. However, the immune responses against apoptotic tumor cells in vivo are poorly understood. To investigate whether apoptotic tumor cells affect anti-tumor immunity, local immune responses in tumor were evaluated by induction of apoptotic tumor cells with herpes simplex virus thymidine kinase (HSVtk)/ ganciclovir (GCV) system. HSVtk gene transduced tumor cells were resulted in apoptosis in vitro. Administration of GCV triggered apoptosis in HSVtk transfected tumor cells in vivo and regressed the tumor. Comprehensive gene expression analysis of the bulk tumor showed that IFNγ and IL-12 were upregulated. CD8+ T cells were increased in the treatment group compared to the control group. The tumor regression by induction of GCV-triggered apoptosis was inhibited by anti-CD8 depleting antibody. These findings indicate that apoptotic tumor cells induce CD8+ T cell-dependent anti-tumor immunity.

Citation Format: Sho Umegaki, Hidekazu Shirota, Chikashi Ishioka. Herpes simplex virus thymidine kinase/ganciclovir-mediated apoptotic tumor cells induce anti-tumor immunity [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 953.
Abstract CT114: Pharmacokinetic analysis of navitoclax in combination with sorafenib in patients with relapsed or refractory solid organ tumors
Authors: Koubek Emily J. , Costello Brian A. , Yin Jun , McGovern Renee M. , Buhrow Sarah A. , Schoon Renee A. , Strand Carrie A. , Jiang Yixing , Borad Mitesh J. , Takebe Naoko , Kaufmann Scott H. , Adjei Alex A. , Reid Joel M.
Published: September 2020

Prior in vitro work in the human hepatoma cell lines Huh7 and HEP3B indicated that combination treatment of the BH3 mimetic, navitoclax, and the multi-kinase inhibitor, sorafenib, was more effective at inducing apoptosis than either compound alone. This current study was part of a phase I clinical trial to determine the maximum tolerated dose of concurrent navitoclax and sorafenib treatment in patients with relapsed or refractory solid organ tumors and sought to characterize the pharmacokinetics (PK) and pharmacodynamics (PD) of both agents in combination. Cleavage of cytokeratin 18 by caspase 3 was used as a biomarker for therapy-induced activation of apoptosis to determine if combination treatment results in an increase in apoptosis as previously observed in in vitro work. PK were assessed in 26 patients (ages 32 - 80) enrolled in a phase I clinical trial (NCT02143401). 150 mg of oral navitoclax was administered once daily for a seven day run-in (beginning Day -7) prior to 150 mg (Dose level 1) or 200 mg (Dose level 2) navitoclax concomitant treatment with 400 mg of twice daily oral sorafenib (Day 1). Samples for pharmacokinetic analysis were obtained on Day -7 and Day 1 prior to dosing and at 1, 2, 4, 8-12, and 24 hours post dosing. PK parameters were estimated by noncompartmental analysis using Phoenix® WinNonlin® Version 6.4. To examine the PD of both agents in combination, cytokeratin 18 cleavage was quantified by ELISA after the 7-day navitoclax run-in and on Day 2 or 4 and Day 8 of navitoclax and sorafenib combination treatment. PK estimates of maximum concentration, exposure, volume of distribution, and clearance for navitoclax on Day -7 and Day 1 were not significantly different, indicating a lack of navitoclax accumulation. Finally, no correlation was found between navitoclax exposure and apoptosis as indicated by cytokeratin-18 cleavage. This work was supported by the NCI Cancer Center Support Grant P30 CA15083 and NCI Experimental Therapeutics Phase I Grant UM1 CA186686.

Citation Format: Emily J. Koubek, Brian A. Costello, Jun Yin, Renee M. McGovern, Sarah A. Buhrow, Renee A. Schoon, Carrie A. Strand, Yixing Jiang, Mitesh J. Borad, Naoko Takebe, Scott H. Kaufmann, Alex A. Adjei, Joel M. Reid. Pharmacokinetic analysis of navitoclax in combination with sorafenib in patients with relapsed or refractory solid organ tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT114.
Abstract CT164: A phase 1 study of abemaciclib in Chinese patients with advanced and/or metastatic cancers
Authors: Hu Xichun , Yang Nong , Zhang Jian , Zhou Chunhua , Ji Dongmei , Shen Weina , Li Wenhua , Han Rubing , Lu Yi , Chapman Sonya C.
Published: September 2020

Background: Abemaciclib, a cyclin-dependent kinase 4 & 6 inhibitor, is approved in combination with endocrine therapy or as a single agent for HR+/HER2- advanced breast cancer patients (pts) outside of China. The safety and PK profile has not been established in Chinese pts.

Patients and methods: In this multicenter, open-label, phase 1 trial, pts were randomized to receive abemaciclib 150 mg or 200 mg orally every 12 hours on a 28-day cycle. The primary objective was to evaluate the safety and tolerability of abemaciclib monotherapy in Chinese pts with advanced and/or metastatic cancers. The secondary objective was to assess PK and antitumor activity.

Results: A total of 25 pts were treated with abemaciclib: 12 in 150 mg cohort and 13 in 200 mg cohort. Pts had a median age of 54 years (range: 29-69) and a median of 4 prior systemic therapies (range: 1-7) for metastatic disease. In two dose cohorts, common (≥25%) treatment emergent adverse event (TEAE) related to study treatment included diarrhea, neutrophil count decreased, white blood cell count decreased, decreased appetite, blood creatinine increased, malaise, anemia, platelet count decreased, nausea, alanine aminotransferase increased and cough. The majority of TEAEs were Grade 1 or 2 in severity. Study treatment related Grade ≥3 TEAE (≥10%) included neutrophil count decreased (32%), platelet count decreased (24%), embolism (16%), diarrhea (12%) and white blood cell count decreased (12%). Four pts (16%) discontinued treatment due to AE. The PK characteristics of abemaciclib and its two major active metabolites (LSN2839567 and LSN3106726) were comparable to those observed in previous studies in non-Chinese populations. No CR was observed. Two pts (8%) achieved PR with one confirmed responder. The disease control rate (CR + PR + SD) was 68% (n=17).

Conclusion: Abemaciclib was well tolerated at both cohorts evaluated in Chinese pts with advanced and/or metastatic cancers. The safety profile and PK characteristics in Chinese pts were similar to those in previous studies in non-Chinese populations. Preliminary antitumor activity was observed and supported further development of abemaciclib in Chinese pts.

ClinicalTrials.gov no.: NCT02919696

Citation Format: Xichun Hu, Nong Yang, Jian Zhang, Chunhua Zhou, Dongmei Ji, Weina Shen, Wenhua Li, Rubing Han, Yi Lu, Sonya C. Chapman. A phase 1 study of abemaciclib in Chinese patients with advanced and/or metastatic cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT164.
Abstract CT183: CD5+ B-cell count is a favorable prognostic factor associated with progression-free survival in glioblastoma patients receiving chemoradiation and pembrolizumab
Authors: Claunch Cheryl J. , Diaz Claire , Roth-Carter Riley A. , Popp Lauren , Fu Rochelle , Huddleston Amy E. , Moussalli Dana L. , Peterson Julie , Uluc Kutluay , Szidonya Laszlo , Fan Guang , Pucci Ferdinando , Barajas Ramon F. , Muldoon Leslie L. , Neuwelt Edward A. , Ambady Prakash
Published: September 2020

The exploratory endpoint for our prospective single-arm study (NCT 03347617) evaluated longitudinal changes in immune cell sub-populations (B-cells, T-cells, NK cells, monocytes, and myeloid cells) in 25 newly diagnosed glioblastoma patients who received standard of care chemoradiation with concurrent pembrolizumab after maximal safe resection. Patient demographics included the following: 15 males, 10 females, age range 25-72 years old, mean age 52 years old, 8 MGMT unmethylated, 17 MGMT methylated, 7 IDH1 mutant, and 18 IDH1 wild-type. Flow cytometry was performed on blood collected at predetermined timepoints (pre-treatment, post-radiation, suspected progression, and confirmed progression) and immune cell sub-populations were evaluated as covariates in survival analysis using Cox proportional hazards regression in R. CD5+ CD19+ B-cell count was significantly associated with progression-free survival at pre-treatment (hazard ratio (HR)= 0.76; likelihood ratio test (LRT) p=0.029) and post-radiation (HR = 0.16; LRT p=0.004) timepoints. No association with progression-free survival was found in 25 other immune cell sub-populations evaluated. The study will continue to monitor for progression. Results of imaging, tissue histology, overall survival analysis and functional studies in animal models are pending. Investigations of the immunological mechanisms underlying the potential anti-tumor activity of CD5+ B-cells are ongoing and include detection and characterization of anti-tumor antibodies, T cell-dependence of the response, and whether it is triggered by pembrolizumab. Modulating CD5+ B-cells, or the antibodies they produce, may have therapeutic implications in improving checkpoint inhibition in glioblastoma.

Citation Format: Cheryl J. Claunch, Claire Diaz, Riley A. Roth-Carter, Lauren Popp, Rochelle Fu, Amy E. Huddleston, Dana L. Moussalli, Julie Peterson, Kutluay Uluc, Laszlo Szidonya, Guang Fan, Ferdinando Pucci, Ramon F. Barajas, Leslie L. Muldoon, Edward A. Neuwelt, Prakash Ambady. CD5+ B-cell count is a favorable prognostic factor associated with progression-free survival in glioblastoma patients receiving chemoradiation and pembrolizumab [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT183.
Abstract CT235: A phase 1b/2 study of onvansertib (PCM-075) in combination with FOLFIRI and bevacizumab for second line treatment of patients with KRAS-mutated metastatic colorectal cancer (mCRC)
Authors: Barzi Afsaneh , Lenz Heinz-Josef , Samuëlsz Errin , Ridinger Maya , Erlander Mark , Bekaii-Saab Tanios S. , Ahn Daniel H.
Published: September 2020

Background: Chemotherapy in combination with targeted agents are standard-of-care options for patients for mCRC with response rates >50% in first line. In the second line setting, efficacy of chemotherapy and targeted agents are much lower with response rates of 5% for FOLFIRI (5-fluorouracil, leucovorin, irinotecan) + bevacizumab (anti-VEGF). New treatment options are urgently needed in particular for the 50 % of patients harboring a KRAS mutation. Polo-like kinase 1 (PLK1) is a serine/threonine kinase, master regulator of the mitotic checkpoint and cell division. PLK1 is overexpressed in CRC and its overexpression is associated with poor prognostic. A genome wide RNAi screen identified PLK1 as a synthetic lethal target in KRAS mutant CRC cells, inducing cell cycle arrest and apoptosis upon inhibition. Onvansertib is an oral, highly selective PLK1 inhibitor that demonstrates single agent and synergistic activity with irinotecan in preclinical CRC models. Additionally, KRAS mutated vs wild-type cells showed higher sensitivity to onvansertib. PLK1 inhibition is a potential target in KRAS-mutated mCRC and onvansertib + FOLFIRI + bevacizumab may provide a new second-line treatment option.

Trial design: The primary objective of this single-arm Phase 1b/2 study is to assess the safety and preliminary efficacy of onvansertib in combination with FOLFIRI and bevacizumab in the second line setting for KRAS-mutated mCRC patients. For the Phase 1b segment, a standard 3 + 3 dose-escalation design is used to determine the maximum tolerated dose or recommended phase 2 dose (RP2D) of onvansertib. As of January 24th 2020, enrollment in the second dose level is ongoing. Efficacy will be determined by objective response rate (ORR) according to RECIST v1.1 (primary endpoint), progression-free survival and reduction in KRAS allelic burden in liquid biopsies (secondary endpoints). In the phase 2, based on a one-sided one sample log-rank test with 10% Type I error, there will be at least 90% power to detect an improvement in ORR from 5% to 20% with 26 patients. Exploratory endpoints include genomic studies of circulating tumor cells and ctDNA to evaluate altered pathways that correlate with patient response. Clinical trial identification NCT03829410.

Citation Format: Afsaneh Barzi, Heinz-Josef Lenz, Errin Samuëlsz, Maya Ridinger, Mark Erlander, Tanios S. Bekaii-Saab, Daniel H. Ahn. A phase 1b/2 study of onvansertib (PCM-075) in combination with FOLFIRI and bevacizumab for second line treatment of patients with KRAS-mutated metastatic colorectal cancer (mCRC) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT235.