bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1729: Reproducible, MoA-reflecting reporter-based bioassays to enable drug development of biosimilars and biobetters
Authors: Moravec Rich , Li Dun , Wilkinson Jennifer , Swanson Brad , Fan Frank , Cong Mei
Published: July 2021

Cytokines and growth factors can be described as small immunomodulatory proteins secreted by a wide variety of cells including fibroblasts, endothelial and stromal cells, whose role it is to regulate surrounding cells in an autocrine, paracrine, or endocrine fashion. Immunocytokines represent a promising class of activators of the immune system, with the potential to be used alone or in combination with other therapeutic modalities. Many are currently FDA approved therapy agents (e.g. IFN, IL-2 and Epo), while others are targets for approved biological blocking therapies to support treatment of a variety of diseases. Examples of cytokine blocking agents include basiliximab (IL-2R), tocilizumab and sarilumab (IL-6R), siltuximab (IL-6), ustekinumab and its biosimilars (IL-12/IL-23 p40), secukinumab (IL-17A), bevasizumab (VEGF), and denosumab (RANKL). Many more are in development and trials as biosimilars and biobetters. IL-2 and IL-15 are still clinically important cytokines as researchers look to improve potency, patient tolerance and response by developing new molecules with sustained and targeted activities. We have developed luciferase reporter bioassays which individually can be used for the quantitation of a variety of cytokines and growth factors including IL-2, IL-6, IL-12, IL-15, IL-17, IL-23, TGF-β, VEGF and RANKL using respective mechanism of action pathways. The bioassay format is based on thaw-and use cells, eliminating the need to establish and pre-culture cytokine responsive cell lines which provides the benefits of convenience, reproducibility, and transferability. We demonstrate these assays measure cytokine response and inhibition with blocking drugs or potency changes from stressed samples. In summary, these reporter-based bioassays provide valuable tools for the development, stability testing, and potency determination in the manufacture of cytokine biosimilars and biobetters.

Citation Format: Rich Moravec, Dun Li, Jennifer Wilkinson, Brad Swanson, Frank Fan, Mei Cong. Reproducible, MoA-reflecting reporter-based bioassays to enable drug development of biosimilars and biobetters [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1729.
Abstract 1730: Up-regulation of C/EBPα inhibits suppressive activity of myeloid cells and potentiates antitumor response in mice and cancer patients
Authors: Hashimoto Ayumi , Sarker Debashis , Reebye Vikash , Jarvis Sheba , Sodergren Mikael H. , Kossenkov Andrew , Raulf Nina , Vasara Jenni , Andrikakou Pinelopi , Meyer Tim , Huang Kai-Wen , Plummer Ruth , Chee Cheng Ean , Spalding Duncan , Pai Madhava , Pinato David J. , Sharma Rohini , Basu Bristi , Palmer Daniel , Ma Yuk-Ting , Habib Robert , Martirosyan Anna , Elasri Naouel , Reynaud Adeline , Rossi John , Cobbold Mark , Habib Nagy , Gabrilovich Dmitry
Published: July 2021

Tumor associated macrophages (TAM) and myeloid-derived suppressor cells (MDSC) are widely implicated in the suppression of immune responses in cancer and are associated with negative clinical outcomes. We report that in mouse tumor models, therapeutic up-regulation of the transcriptional factor C/EBPα with small activating RNA (MTL-CEBPA) blocks the suppressive activity of monocytic (M) MDSC and TAM without affecting polymorphonuclear (PMN) MDSC. MTL-CEBPA treatment demonstrated antitumor activity that was dependent on T cells. Combination of MTL-CEBPA and anti-PD1 antibody or with PMN-MDSC targeted therapy resulted in marked antitumor effect. A phase I trial was conducted in 36 patients with advanced hepatocellular carcinoma (HCC). Marked decrease in M-MDSC and the expression of genes and proteins involved in immune suppressive activity of these cells were observed. Combined treatment with MTL-CEBPA and sorafenib resulted in a 27% objective radiological response and three complete responses in patients with virally associated HCC. Tissue biopsies from these patients demonstrated decrease in M2 polarized macrophages within the tumors. Thus, therapeutic up-regulation of C/EBPα inhibited suppressive myeloid cells that resulted in potent antitumor effect in mice and with encouraging clinical response in cancer patients. We are currently recruiting to a multi-centre study of MTL-CEBPA in combination with a PD-1 inhibitor (pembrolizumab) in adult patients with advanced solid tumors (TIMEPOINT - ClinicalTrials.gov Identifier: NCT04105335).

Citation Format: Ayumi Hashimoto, Debashis Sarker, Vikash Reebye, Sheba Jarvis, Mikael H. Sodergren, Andrew Kossenkov, Nina Raulf, Jenni Vasara, Pinelopi Andrikakou, Tim Meyer, Kai-Wen Huang, Ruth Plummer, Cheng Ean Chee, Duncan Spalding, Madhava Pai, David J. Pinato, Rohini Sharma, Bristi Basu, Daniel Palmer, Yuk-Ting Ma, Robert Habib, Anna Martirosyan, Naouel Elasri, Adeline Reynaud, John Rossi, Mark Cobbold, Nagy Habib, Dmitry Gabrilovich. Up-regulation of C/EBPα inhibits suppressive activity of myeloid cells and potentiates antitumor response in mice and cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1730.
Abstract 1828: AZD8853: A novel antibody targeting GDF15 for immunotherapy refractory tumors
Authors: Hurt Elaine , Thomas Suneetha , Mulgrew Kathy , Blackmore Stephen , Moynihan James , Cusdin Fiona , Dodd Roger , Cariuk Peter , Sigurdardottir Anna , Brannigan Emily , Dobson Claire , Kumar Rakesh , Cobbold Mark
Published: July 2021

Immunotherapy has revolutionized patient care, however, the majority of patients with cancer still do not benefit from this treatment modality. This is due to many factors, including a complex tumor microenvironment (TME) that has too few functional effector cells and/or the presence of many inhibitory cells. Understanding how to remodel the TME to potentiate productive immunity against cancer cells is an active area of research. Growth and Differentiation Factor 15 (GDF-15) is a member of the TGF-beta superfamily that is overexpressed by many solid tumors and is implicated in dampening immune responses. The present study was aimed at understanding the role of GDF-15 in tumor immune biology. We show that GDF-15 can inhibit the differentiation and activation of human monocyte-derived dendritic cells (DCs) and prevent T cell activation. Furthermore blockade of GDF-15 by AZD8853, an anti-GDF15 monoclonal antibody, can restore these activities in vitro. Tumors derived from GDF15 knock-out syngeneic cell lines, Renca and MC-38, show 2-3 fold increases in T cells and activated DCs in the TME as compared to tumors derived from isogeneic parental cells. Treatment of mice with anti-GDF15 mAb leads to substantial anti-tumor activity in anti-PD-L1 refractory LL/2 and MBT2 syngeneic tumors with 50% of the animals showing complete tumor regressions. Coupled with this anti-tumor activity, we show that after 2 doses of anti-GDF15 mAb there is an increase in both activated T cells and DCs in the TME. Depletion of T cells, using anti-CD4 and anti-CD8, in mice ablates the anti-tumor activity observed with anti-GDF15 mAb treatment. These results suggest that inhibition of GDF15 by AZD8853 may be an attractive therapeutic strategy for patients with solid tumors that have high expression of GDF15.

Citation Format: Elaine Hurt, Suneetha Thomas, Kathy Mulgrew, Stephen Blackmore, James Moynihan, Fiona Cusdin, Roger Dodd, Peter Cariuk, Anna Sigurdardottir, Emily Brannigan, Claire Dobson, Rakesh Kumar, Mark Cobbold. AZD8853: A novel antibody targeting GDF15 for immunotherapy refractory tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1828.
Abstract 1914: Orally available oncolytic reovirus, RC402, effectively promotes anti-cancer immunity and synergizes with immune checkpoint blockade in colon cancer
Authors: Kim Chan , Chon Hong Jae , Lee Hye Jin , Lee Won Suk , Yang Hannah , Kim Jeong Hun , Kong So Jung , Lee Yu Seong , Lee Seung Joon , Gansukh Enkhtaivan , Song Ki-Hoon , Lee Yeon-Sook , Kang Beodeul
Published: July 2021

Introduction: Reoviruses are replication-competent and selectively infect and destroy cancer cells. Although the most common route of oncolytic virotherapy is intratumoral or intravenous administration, these routes are often not clinically feasible because of tumor inaccessibility, tumor multiplicity, and systemic toxicities. Here, we developed an orally available oncolytic reovirus, RC402, to elicit potent anti-tumor immune responses without the above mentioned limitations and thereby maximize the efficacy of PD-1 immune checkpoint blockade in colon cancer.

Method: MC38 or CT26 colon cancer-bearing immunocompetent mice were treated with RC402 and/or anti-PD-1 antibody. Tumor growth was monitored after treatment and comprehensively analyzed by flow cytometry and/or multiplex tissue imaging.

Results: RC402 treatment effectively delayed tumor growth regardless of the route of administration (per os as well as intratumorally). In particular, orally administered RC402 was well tolerated without gross toxicity and interacted with intestinal immune cells, eliciting adaptive T cell responses within intestinal lymphoid organs such as Peyer's patch. Most of the RC402 was cleared in the gastrointestinal tract within 10 days of the first treatment, and it was not detectable in the blood stream or major organs after oral administration. However, RC402 selectively induced strong and durable anti-tumor immunity in distant tumor tissues. Oral RC402 monotherapy markedly increased CD8+ cytotoxic T cells and decreased CD4+CD25+Foxp3+ regulatory T cells in distant colon cancers, while there were no significant changes in tumor-associated myeloid cells. Finally, oral RC402 treatment cooperated with anti-PD-1 blockade to further suppress colon cancer growth and augment anti-tumor immunity within the tumor microenvironment, leading to complete regression of tumors and survival benefit of tumor-bearing mice.

Conclusion: Our study demonstrates that orally available oncolytic reovirus, RC402, could induce potent anti-cancer immune responses and effectively suppress colon cancer progression in combination with anti-PD-1 blockade.

Citation Format: Chan Kim, Hong Jae Chon, Hye Jin Lee, Won Suk Lee, Hannah Yang, Jeong Hun Kim, So Jung Kong, Yu Seong Lee, Seung Joon Lee, Enkhtaivan Gansukh, Ki-Hoon Song, Yeon-Sook Lee, Beodeul Kang. Orally available oncolytic reovirus, RC402, effectively promotes anti-cancer immunity and synergizes with immune checkpoint blockade in colon cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1914.
Abstract 1924: Therapeutic potential of inhibitor of apoptosis protein (IAP) inhibitor APG-1387 combined with DR5 agonist monoclonal antibody (mAb) CTB-006 in preclinical models of solid tumors
Authors: Li Qiang , Fang Douglas D. , Li Zhe , Yang Dajun , Cao Fengqi , Zhai Yifan
Published: July 2021

TNF-related apoptosis-inducing ligand (TRAIL) receptor (DR4 or DR5) agonists are promising agents for cancer therapy because they induce apoptosis selectively in cancer cells. However, their clinical effect is hampered by either primary or acquired resistance in cancer cells. Second mitochondria-derived activator of caspase (Smac) mimetics that antagonize the IAPs potently sensitize cancer cells to TRAIL-induced apoptosis in a caspase-8-dependent manner. We evaluated antitumor effects of small-molecule IAP antagonist APG-1387combined with an agonist mouse mAb directed against TRAIL death receptor type 5 (DR5) termed CTB-006 in the preclinical setting. Both agents are in phase I/II clinical development for patients with solid tumors. In vitro the combination treatment showed synergy in a dose-dependent manner across various cancer cell lines, as evidenced by synergistic antiproliferative activity and enhanced induction of caspase-3 cleavage. Potential synergistic in vivo antitumor activity of the combination was then assessed in human triple negative breast cancer (TNBC) xenograft models in mice. Specifically, in MDA-MB-231 and 2LMP TNBC xenograft models, either APG-1387 or CTB-006 single agent exhibited limited antitumor activity, with T/C (%) values of >35% (T, tumor volume in the treatment group; C, tumor volume in the vehicle control group). Only one tumor showed partial regression (PR) by DR5 treatment. Addition of APG-1387 potentiated this effect, with the combination treatment leading to T/C values of 3% to 15%, and complete regression, PR, or stable disease in all treated tumors. In summary, our results suggest great potential of combination therapy with APG-1387 and CTB-006 for solid tumor therapy and deserves further clinical investigation.

Citation Format: Qiang Li, Douglas D. Fang, Zhe Li, Dajun Yang, Fengqi Cao, Yifan Zhai. Therapeutic potential of inhibitor of apoptosis protein (IAP) inhibitor APG-1387 combined with DR5 agonist monoclonal antibody (mAb) CTB-006 in preclinical models of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1924.
Abstract 1953: Q901, a selective CDK7 inhibitor, a potential new strategy for primary and CDK4/6 inhibitor resistant ER-positive breast cancer
Authors: Yu Donghoon , Jeon Yeejin , Park Dongsik , Seo Mooyoung , Ahn Wongyun , Kim Jaeseung , Nam Kiyean
Published: July 2021

CDK4/6 inhibitors, in combination with hormone therapy, has made a breakthrough in treatment of hormone receptor-positive, HER2-negative metastatic breast cancers. However, in clinical practice, a substantial number of patients who responded to CDK4/6 inhibitors eventually develop resistance within 2-3 years. Current knowledge of the molecular mechanisms of CDK4/6 inhibitor resistance is under investigation , with the loss of function of the retinoblastoma (RB) protein the most frequently observed change in resistance to CDK4/6 inhibitors. RB loss of function by CDK4/6 inhibitors appears an irreversible mechanism of resistance while gain of cyclin E, and overexpression of CDK2 reducing cyclin D1-CDK4/6 dependency which results in the resistant cell to re-enter into s-phase. Thus, inhibition of the cyclin E-CDK2 axis may be effective in overcoming resistance to CDK4/6 inhibitors. We report a novel treatment strategy that targets Cyclin-dependent kinase 7 (CDK7) in CDK4/6 inhibitor-resistant, ER+ breast cancer. Q901 is a novel highly-selective inhibitor against CDK7 and demonstrates good functional inhibition of CDK activating kinase (CAK) activities leading to activation of CDK4, 6 and CDK2 in vitro and in vivo. Q901, monotherapy, effectively inhibited tumor growth in ER+ breast cancer xenograft model as well as CDK4/6 inhibitor resistant PDX model. The results suggest a potential for Q901 in treatment of hormone receptor-positive, HER2-negative metastatic breast cancer, regardless of resistance status to CDK4/6 inhibitors.

Citation Format: Donghoon Yu, Yeejin Jeon, Dongsik Park, Mooyoung Seo, Wongyun Ahn, Jaeseung Kim, Kiyean Nam. Q901, a selective CDK7 inhibitor, a potential new strategy for primary and CDK4/6 inhibitor resistant ER-positive breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1953.
Abstract 2170: Proteogenomic and metabolomic characterization of human glioblastoma
Authors: Wang Liang-Bo , Karpova Alla , Gritsenko Marina A. , Kyle Jennifer E. , Cao Song , Li Yize , Rykunov Dmitry , Colaprico Antonio , Rothstein Joseph , Hong Runyu , Stathias Vasileios , Cornwell MacIntosh , Petralia Francesca , Smith Richard D. , Iavarone Antonio , Chheda Milan G. , Barnholtz-Sloan Jill S. , Rodland Karin D. , Liu Tao , Ding Li ,   Clinical Proteomic Tumor Analysis Consortium
Published: July 2021

Glioblastoma (GBM) is the most aggressive nervous system cancer, with median survival under 2 years. Understanding its molecular pathogenesis is crucial for improving diagnosis and treatment. We performed an integrated analysis of genomic, proteomic, post-translational modification and metabolomic data on 99 treatment-naive GBMs. We identified key phosphorylation events (e.g., phosphorylated PTPN11 and PLCG1) as potential switches mediating oncogenic pathway activation as well as potential targets for EGFR-, TP53- and RB1-altered tumors. We detected immune subtypes, driven by the presence of distinct immune cell populations using bulk omics, validated by snRNA-seq, and they were correlated with specific expression and histone acetylation patterns. Acetylation of histone H2B in classical-like and immune-low GBM was driven largely by BRDs, CREBBP, and EP300. Integrated metabolomic and proteomic data identified specific lipid distributions across subtypes and distinct global metabolic changes in IDH mutated tumors. By comparing the adult GBM proteomics to the adolescent and young adult (AYA) GBM cohort from the HOPE study, we found downregulated IDH1 expression and up-regulated expression of genes in the NADH dehydrogenase family, including NDUFB1, and NDUFB3 among others, which may be related to high IDH1 mutation frequency in AYA. This work highlights biological relationships which could potentially aid GBM patient stratifications for more effective treatments.

Citation Format: Liang-Bo Wang, Alla Karpova, Marina A. Gritsenko, Jennifer E. Kyle, Song Cao, Yize Li, Dmitry Rykunov, Antonio Colaprico, Joseph Rothstein, Runyu Hong, Vasileios Stathias, MacIntosh Cornwell, Francesca Petralia, Richard D. Smith, Antonio Iavarone, Milan G. Chheda, Jill S. Barnholtz-Sloan, Karin D. Rodland, Tao Liu, Li Ding, Clinical Proteomic Tumor Analysis Consortium. Proteogenomic and metabolomic characterization of human glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2170.
Abstract 222: Towards patient-specific optimization of neoadjuvant treatment protocols for breast cancer based on image-based fluid dynamics
Authors: Wu Chengyue , Hormuth David A. , Pineda Federico , Karczmar Gregory S. , Yankeelov Thomas E.
Published: July 2021

Introduction: Standard-of-care neoadjuvant therapeutic regimens are based on clinical trials designed to identify treatment protocols at the population level, which cannot capture the unique characteristics of individual patients. Moreover, it is impossible for clinical trials to experimentally evaluate all the possible treatment combinations and dosing strategies. Mechanism-based, mathematical modeling can potentially address this critical barrier to achieving truly personalized treatment. In this contribution, we present preliminary results using a fluid dynamics model personalized with a patient's imaging data to optimize a drug injection protocol in breast cancer.

Methods: Nine breast cancer patients are included in this study. MRI data are acquired, processed, and used to estimate hemodynamics and imported to our drug delivery model. By varying the dosing schedule, the model predicts varying dynamics of drug distribution throughout the breast. We define an objective function, MSTD, balancing the treatment efficacy and toxicity, and use it to optimize the injection protocol for each patient. The injection schedules tested include: (a) single injection on day 1 of each 3-week cycle; double injections of half the total dose each at (b) day 1 and 2, (c) day 1 and 3, (d) day 1 and 5, and (e) day 1 and 8 within each 3-week cycle. The doses tested vary from 0 to 100 μg/ml of maximal plasma concentration. Improvement ratio of the optimal protocol to a standard protocol, 10 μg/ml via schedule (a), is measured.

Results: The optimal protocol and improvement are reported for each patient in Table 1.

Conclusion: Our modeling system can efficiently solve the personalization of drug injection protocol as an optimal control problem. Different patients have different optimal treatment protocols, each of which is predicted to outperform the standard protocol.

Table 1.Optimal injection protocol for individual patientsPatientOptimal scheduleOptimal dose (μg/ml)Improvement ratio1(e)8.891.492(e)6.071.823(e)5.882.124(e)7.362.415(e)5.193.266(e)5.203.377(e)5.703.598(e)4.103.079(e)4.593.49NCI U01CA142565, U01CA174706, R01CA218700, R01CA172801, U24CA226110, P30CA014599. CPRIT RR160005.

Citation Format: Chengyue Wu, David A. Hormuth, Federico Pineda, Gregory S. Karczmar, Thomas E. Yankeelov. Towards patient-specific optimization of neoadjuvant treatment protocols for breast cancer based on image-based fluid dynamics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 222.
Abstract 2391: Computation of a user-friendly composite score from three prostate cancer biomarkers
Authors: Pal Gargi , Asante-Asamani Emmanuel , Liu Leslie , Ogunwobi Olorunseun O.
Published: July 2021

Summary: Prostate cancer (PCa) is the most commonly diagnosed solid organ cancer in men worldwide. Current diagnosis of PCa includes use of initial prostate specific antigen assay which has a high false positive rate, low specificity, and low sensitivity. Consequently, it results in overdiagnosis and overtreatment, leaving patients with unintended health complications from the side effects of unnecessary prostate biopsies and treatment. PCa biomarkers are being discovered to address this unmet need. Here, we report creation of a composite score based on three PCa biomarkers, plasmacytoma variant translocation 1 exon 4A, exon 4B, and exon 9. Statistical analysis of copy numbers derived from a real-time quantitative polymerase chain reaction - based assay showed these PCa biomarkers to be linearly separable. We trained a supervised learning algorithm using support vector classifiers to generate a classification hyperplane from which a composite score is developed. Our aggregate score when applied to test data from non-cancerous prostate epithelial cells and PCa cells accurately classified 100% PCa cells. Creation of this 3-biomarker based composite score lays the groundwork for clinical trial of its use in PCa diagnosis.

Citation Format: Gargi Pal, Emmanuel Asante-Asamani, Leslie Liu, Olorunseun O. Ogunwobi. Computation of a user-friendly composite score from three prostate cancer biomarkers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2391.
Abstract 281: pH-sensitive liposome for siRNA delivery to treat drug-resistant ovarian cancer
Authors: Alatise Kharimat Lora , Gardner Samantha , Alexander-Bryant Angela
Published: July 2021

Introduction: With a 5-year survival rate of 47%, ovarian cancer is the 5th leading cause of death amongst women worldwide. Over 75% of patients experience recurrence after initial treatment, indicating a need for improved treatment options. Drug resistance is a major barrier hindering the success of current treatment methods. Our study analyzes the characteristics of a stimuli-sensitive liposomal delivery system for combatting drug resistance. Our delivery system will deliver bioactive siRNAs targeting genes related to drug resistance, cell proliferation, and apoptosis. In this study, we investigate the characteristics of the liposomes to determine particle size, surface charge, and ability to encapsulate/bind both siRNAs. We also begin to investigate the delivery potential of the pH-sensitive liposomal formulation in vitro using ovarian cancer cell lines.

Methods: Empty and siRNA loaded cationic, pH-sensitive liposomes (CHEMS-LPs) were synthesized by the thin-film hydration method. Liposome size, zeta potential, and polydispersity index (PDI) were measured by dynamic light scattering (DLS). To measure siRNA encapsulation efficiency, fluorescently labeled siRNA was loaded into CHEMS-LPs and subjected to centrifugation to pellet the LPs. Fluorescence spectroscopy was used to detect siRNA in the supernatant. The toxicity of unloaded CHEMS-LPs was determined by an MTS assay using OVCAR3 (drug-sensitive) and OVCAR3-T40 (drug-resistant) human ovarian cancer cells.

Results: The size and zeta potential of blank and siRNA-loaded CHEMS-LPs were 97.88 ± 2.39 nm and 29.0 ± 2.00 mV, and 80.78 ± 0.77​ nm and 13.1 ±1.66​ mV, respectively. The positively charged zeta potential confirms the cationic nature of our liposomes. The PDI demonstrated that the liposomes were unimodal and monodisperse with PDI values of less than 0.300 for each formulation. In addition, siRNA was successfully bound to CHEMS-LPs through electrostatic interaction with the cationic lipid layer, resulting in an encapsulation efficiency of 99.6%

Conclusion: CHEMS-LPs are pH-sensitive, cationic, monodisperse liposomes able to encapsulate siRNAs in order to mediate delivery into ovarian cancer cells. Their stable structure, positive charge, and low cytotoxicity is promising for future studies, including delivery of bioactive siRNAs to stimulate downregulation of target genes related to drug resistance.

Acknowledgements: This work was supported in part by the National Science Foundation EPSCoR Program under Award # OIA-1655740. We would like to thank George Duran from Stanford University for donating the OVCAR3-T40 cell line.

Citation Format: Kharimat Lora Alatise, Samantha Gardner, Angela Alexander-Bryant. pH-sensitive liposome for siRNA delivery to treat drug-resistant ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 281.
Abstract 2903: The exosome marker CD63 and Caveolin-1 in breast cancer patients
Authors: Iwabuchi Erina , Miki Yasuhiro , Kanai Ayako , Ishida Takanori , Sasano Hironobu
Published: July 2021

The tetraspanin CD63, a proposed exosome marker, has been reported to be expressed in solid tumors. For instance, CD63 status in carcinoma cells was reported to be a significant independent prognostic factor in gastric cancer patients, with its overexpression causing adversity in patients with gastrointestinal stromal tumors. However, the expression of CD63 has remained virtually unknown in breast cancer pathological specimens. In addition, the detection of high levels of exosomes expressing CD63 and Caveoloin-1 in the plasma of melanoma patients was reported as a novel tool for the clinical management of cancer patients. Caveolin-1 has also been reported to negatively regulate the endocytosis of exosomes. Tetraspanin proteins are shown to form complicated interaction networks in cells to exert their functions. In this study, we immunolocalized CD63 and Caveolin-1 in the surgical pathology specimens of 88 breast cancer patients. CD63 was immunolocalized in the cytoplasm of both the cancer and stromal cells. The number of CD63-positive cancer cells was significantly higher in HER2-positive patients and the levels of CD63-positive stromal cells were also significantly higher in those with high pathologic T factor (pT) and proliferation marker protein Ki-67 labeling index and low pathologic N factor (pN). The number of CD63-double-positive cancer cells and stromal cells was associated with high histological grade, high pT, and high Ki67 expressions. CD63-positive cancer cells and Caveolin-1-positive cancer cells were both significantly higher in Estrogen receptor-positive breast cancer patients with high histological grade and pT. To the best of our knowledge, this is the first study demonstrating the significance of CD63 in breast cancer. Our results indicated that CD63-double-positive cancer cells and stromal cells could be involved in clinically and biologically aggressive subtypes of breast cancer. Further studies are required to clarify the clinical significance of the associations between CD63 and Caveolin-1 in patients with breast cancer.

Citation Format: Erina Iwabuchi, Yasuhiro Miki, Ayako Kanai, Takanori Ishida, Hironobu Sasano. The exosome marker CD63 and Caveolin-1 in breast cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2903.
Abstract 2977: Organoid-T-cell co-cultures for preclinical testing of adoptive cell and cancer immunotherapy
Authors: Hombrink Pleun , Mardpour Soura , Spaan Ewout , Hanrath Jarmil , Pourfarzad Farzin , Mullenders Jasper , Overmeer Rene , Robert G.J , Vries  , Sylvia F , Boj
Published: July 2021

Recent advances in cancer immunotherapy had a positive impact on the life expectancy of patients with a large range of clinical indications. With new treatment strategies and druggable targets being identified at an increasing pace, the number of patients eligible for cancer immunotherapy is expected to expand steadily. However, promising therapeutic developments face hurdles in translating preclinical findings into therapy. Challenges range from lack of confidence in animal cancer models, inter-tumor heterogeneity and the absence of cellular microenvironment. Hubrecht Organoid Technology (HUB) offers an innovative alternative, build on the discovery that adult stem cells proliferate and organize into three-dimensional organotypic structures when they are embedded into Matrigel. HUBOrganoids™ are generated from healthy and disease tissues and stored as “living” biobanks with high quality and reproducibility. HUB Organoids recapitulate complex characteristics of the original parental tissue, including molecular heterogeneity, and morphological and functional traits. HUB has developed organoid-T-cell co-culture systems that allow a physiologic representation of the complexity of interactions in the tumor microenvironment, which is important for evaluating the effects of novel therapies. HUB offers an innovative platform combining image-based analysis with flow cytometry to visualize and quantify T-cell-tumor interactions as well as measurements of T-cell cytotoxicity against tumor (and normal-matched) organoids for colorectal and several other cancers. Our platform offers a powerful strategy for the development and validation of cancer immunotherapy and may help to screen the efficacy of immune checkpoint blockade or bispecific antibodies. In addition, cancer organoid-T-cell co-culture may also predict the functionality of tumor-infiltrating lymphocytes (TIL) and chimeric antigen receptor (CAR)-engineered T cells. As such, our platform offers opportunities in preclinical development and could become a diagnostic tool to predict individual patient response to immunotherapy.

Citation Format: Pleun Hombrink, Soura Mardpour, Ewout Spaan, Jarmil Hanrath, Farzin Pourfarzad, Jasper Mullenders, Rene Overmeer, G.J Robert, Vries, F Sylvia, Boj. Organoid-T-cell co-cultures for preclinical testing of adoptive cell and cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2977.
Abstract 2993: Intraductal xenografts model ERα-positive invasive lobular carcinoma of the breast
Authors: Sflomos George , Battista Laura , Aouad Patrick , De Martino Fabio , Scabia Valentina , Stravodimou Athina , Ayyanan Ayyakkannu , Ifticene-Treboux Assia ,   RLS, Bucher Philipp , Fiche Maryse , Ambrosini Giovanna , Brisken Cathrin
Published: July 2021

Invasive lobular carcinoma (ILC) is the most frequent special histological subtype of breast cancer, typically characterized by loss of E-cadherin. It has clinical features distinct from other estrogen receptor-positive (ER+) breast cancers but the molecular mechanisms underlying its characteristic biology are poorly understood because we lack experimental models to study them. By xenografting lobular cells to the milk ducts, we recapitulate the human disease, including invasion and metastasis to clinically relevant organs. Using patient-derived intraductal xenografts from lobular and non-lobular ER+ HER2- tumors to compare global gene expression we identify extracellular matrix modulation as a lobular carcinoma cell-intrinsic trait. Analysis of TCGA patient datasets shows matrisome signature is enriched in lobular carcinomas with overexpression of elastin, collagens, and the collagen modifying enzyme LOXL1. Pharmacological treatment and silencing of LOXL1 expression decrease tumor growth, invasion, and metastasis by disrupting ECM structure resulting in decreased ER signaling. We conclude that LOXL1 inhibition is a promising therapeutic strategy for ILC. This is the first study of a hormone-responsive ER+ preclinical lobular model that mimics their clinical counterparts and opens opportunities for the development and evaluation of therapies.

Citation Format: George Sflomos , Laura Battista, Patrick Aouad, Fabio De Martino, Valentina Scabia, Athina Stravodimou, Ayyakkannu Ayyanan, Assia Ifticene-Treboux, RLS, Philipp Bucher, Maryse Fiche, Giovanna Ambrosini, Cathrin Brisken. Intraductal xenografts model ERα-positive invasive lobular carcinoma of the breast [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2993.
Abstract 305: ELU001, a targeted C'Dot drug conjugate (CDC) for the treatment of folate receptor alpha (FRα) overexpressing cancers
Authors: Adams Gregory Paul , Ma Kai , Venkatesan Aranapakam , Chen Feng , Wu Fei , Turker Melik , Gardinier Thomas , Chen Peiming , Patel Vaibhav , Bayever Eliel , Rudick Paul , Germano Geno
Published: July 2021

CDCs are novel ultra-small (6-7 nm) nanoparticle drug conjugates that have been demonstrated to be capable of faster tumor targeting and deeper tumor penetration than antibody drug conjugates in animal models. CDCs are capable of targeting tumors in the brain and pancreas that are difficult to access, while exhibiting limited exposure to normal tissues due their efficient renal elimination. CDCs are composed of a silica core, in which Cy5, a far red dye is covalently encapsulated. The silica core is covalently coated with a layer of polyethylene glycol which is then functionalized with targeting moieties and payloads. ELU001 is a CDC functionalized with ~20 molecules of the topoisomerase-1 inhibitor exatecan linked via a proteolytic cleavable linker as a payload and ~15 folic acids to provide targeting to FRα overexpressing cancers. ELU001 is rapidly internalized into FRα expressing cells and is trafficked to the lysosome where the payload is released from the CDC. ELU001 exhibits potency in the low single digit nanomolar to sub-nanomolar range against cancer cells that express 3+ (KB, IGROV-1) and 2+ (SK-OV-3, HCC827 and OVCAR-3) levels of FRα after a 6-hr exposure in a 7-day viability study. In contrast, an anti-FRα ADC based ADC mirvetuximab soravtansine exhibits lower potency (>100 nM IC50) against SK-OV-3 and HCC827 cells and 40 nM IC50 against OVCAR-3 cells. ELU001 exhibits potent efficacy against established s.c. KB human cervical tumor xenografts in immunodeficient mice with significantly better efficacy and safety than free exatecan payload. It is also effective in treating established SK-OV-3 tumors with lower (2+) FRα expression, a setting where the ADC is again less effective. IND-enabling nonclinical studies are currently underway to prepare for initiation of a first-in-human phase 1 clinical trial in subjects with FRα overexpressing cancers in the second half of 2021.

Citation Format: Gregory Paul Adams, Kai Ma, Aranapakam Venkatesan, Feng Chen, Fei Wu, Melik Turker, Thomas Gardinier, Peiming Chen, Vaibhav Patel, Eliel Bayever, Paul Rudick, Geno Germano. ELU001, a targeted C'Dot drug conjugate (CDC) for the treatment of folate receptor alpha (FRα) overexpressing cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 305.
Abstract 3070: Lung cancer TTFields treatment planning sensitivity to errors in torso segmentation
Authors: Atya Hadas Ben , Peles Oren , Shamir Reuben , Bomzon Zeev
Published: July 2021

Introduction: Tumor Treating Fields (TTFields) is a treatment modality for glioblastoma multiforme (GBM) and other malignant tumors, utilizing low-intensity, intermediate frequency (100-300kHz) alternating electric field delivered through noninvasive transducer arrays. TTFields are currently being tested in a phase III clinical trial for the treatment of advanced Non-Small Cell Lung Cancer (NSCLC). Previous studies have demonstrated that the treatment efficacy increases when the dose of TTFields delivered to the tumor is at least 1 V/cm. Thus, personalized simulations to estimate the dose are performed as part of the patient treatment planning. For NSCLC treatment, these simulations require the segmentation of torso tissues. We are currently developing a semi-automatic software for the segmentation of these tissues. Achieving highly accurate segmentation is time consuming and not always necessary. Therefore, in this study we assess the level of segmentation accuracy that is required for TTFields dose estimation.

Methods: We introduce a novel pipeline for evaluating the sensitivity of TTFields treatment planning errors in the segmentation of torso tissues. To this end, we incorporated an expert-segmented torso volume and artificially placed NSCLC tumors of different sizes in the vicinity of the tested torso tissue. We employed relaxations to the segmentation algorithm and derived the TTFields distribution with and without the simulated segmentation errors. We then computed the treatment planning error as the per-voxel average deviation of the TTFields dose computed over the erroneous segmentation from the reference one. The dose was calculated over the simulated tumor location and over the entire lung volume.

Results: We have evaluated our sensitivity analysis pipeline on 9 different test cases. Based on previous analysis, we have set our tolerable target error to be 0.1 V/cm. Our results show that 6 out of the 9 tests were within the target, whereas the other 3 exceeded the target, requiring algorithmic refinements.

Conclusions: We have presented a method for estimating the sensitivity of lung cancer TTFields treatment planning to segmentation errors. This method is used to evaluate the required accuracy of the semi-automatic torso segmentation tool that we are currently developing. Our method can be further extended to other types of tumors in different regions of the body.

Citation Format: Hadas Ben Atya, Oren Peles, Reuben Shamir, Zeev Bomzon. Lung cancer TTFields treatment planning sensitivity to errors in torso segmentation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3070.
Abstract 3170: Targeting tumor-associated astrocyte dependence in glioblastoma treatment
Authors: Domino Joseph S. , Alvarado Anthony , Arnold Levi , Gunewardena Sumedha , Akhavan David , Thomas Sufi M.
Published: July 2021

Glioblastoma (GBM) is the most common malignant primary brain tumor and remains challenging to treat due to its aggressive nature with high rate of recurrence. Despite advances in therapy, prognosis is poor with median survival of 19 months with maximal therapy. The normal astrocytes within the GBM TME undergo a phenotypic shift, promoting alterations supportive of tumor growth. There is increasing attention on the role of tumor-associated astrocytes (TAA) in GBM progression and resistance to therapy. Previous studies assessing astrocyte support of GBM employ astrocytes derived from murine or fetal sources. We have isolated TAAs from patients with GBM as well as normal human astrocytes (NHA) from cancer-free patients undergoing surgical treatment of epilepsy. The cells are maintained at a low passage number (<10 passes). Our data emphasize the supportive role these cells in GBM progression and resistance to GBM therapy. Briefly, conditioned media (CM) from non-malignant, GFAP positive TAAs, demonstrate a propensity to induce invasion and migration of U87 GBM cells compared to the NHA CM. In addition, TAA CM significantly increased the IC50 dose of U87 cells treated with temozolomide from 536 μM to 1351 μM demonstrating treatment resistance (p<0.001). TAA CM induced temozolomide resistance of the GBM cells can be abolished with supra-therapeutic dosing. RNA sequencing (RNAseq) of two TAA and three NHA samples revealed 399 differentially expressed genes identified with 38 of those upregulated genes coding extracellular products. Expression data was verified by quantitative polymerase chain reaction (qPCR), thus validating the differential expression profile generated by RNAseq. The differential expression data was explored further using Ingenuity Pathway Analysis (IPA) and gene set enrichment analysis (GSEA). Attention was focused on genes with excreted factors as products or involved in the regulation of critical excreted products. We identified and validated high expression of IL1β in TAAs compared to NHAs. RNAseq data revealed multiple potential pathways for targeted therapies aimed at modulating the effect of TAAs in the tumor microenvironment. In ongoing studies, we will determine the efficacy of IL1β in attenuating the TAA-induced temozolomide resistance in GBM. These studies reveal for the first time a highly clinically relevant approach to attenuate TAA-facilitated GBM progression and therapy resistance.

Citation Format: Joseph S. Domino, Anthony Alvarado, Levi Arnold, Sumedha Gunewardena, David Akhavan, Sufi M. Thomas. Targeting tumor-associated astrocyte dependence in glioblastoma treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3170.
Abstract 336: Gut microbiome predicts response to CDK4/6 inhibitor and immune check point inhibitor combination in patients with hormone receptor positive metastatic breast cancer
Authors: Wong Chi Wah , Yost Susan E. , Lee Jin Sun , Highlander Sarah K. , Yuan Yuan
Published: July 2021

Background: CDK4/6 inhibitors (CDK4/6i) have been shown to modulate immune responses in the preclinical setting. Palbociclib is a front-line therapy for hormone receptor positive (HR+) metastatic breast cancer (MBC), and the combination with immune check point inhibitors (ICI) is increasingly being studied. An ongoing phase I trial was designed to test the safety and efficacy of palbociclib, pembrolizumab, and letrozole in postmenopausal women with HR+ HER2- MBC (NCT02778685). Stool microbiome was collected and analyzed. The aim of this study is to determine the association of gut microbiota and response using metagenome sequencing data through a machine learning model.

Methods: Postmenopausal women with histologically proven stage IV HR+ HER2- MBC were enrolled. Stool samples were collected at baseline and during treatment for analysis using metagenome sequencing. Response per RECIST 1.1 were grouped into: responders (complete response or partial response) and non-responders (stable disease or progressive disease). Using metagenomic relative abundance data, a gradient-boosted tree model was developed with leave-one-patient-out cross validations to predict patient response at baseline. Kruskal-Wallis tests were used to assess the differences of the most important microbiota relative abundance (generated from the machine learning model) between responders and non-responders.

Results: Forty-seven stool samples from 11 patients were collected at baseline and during treatment, and metagenome sequencing was performed. For predictive modeling, the validation Area Under the Receiver Operating Characteristic Curve (AUROC) and Area Under the Precision Recall Curve (AUPRC) were 0.71 and 0.83, respectively. Among the top 5 features from the model, patients with a larger relative abundance of Gemmiger formicillis have increased probability of responding to therapy (p<0.05 uncorrected), whereas an increase of Bacteroides vulgatus have reduced probability of responding to therapy (p<0.05 uncorrected). The relative abundance of Gemmiger formicillis at baseline has been reported in recent studies to be higher in patients with long term benefit (Aarnoutse et al. 2017). Thus, there is increasing evidence that gut microbiota plays a role in the pathogenesis of breast cancer and response of MBC patients to systemic cancer therapy.

Citation Format: Chi Wah Wong, Susan E. Yost, Jin Sun Lee, Sarah K. Highlander, Yuan Yuan. Gut microbiome predicts response to CDK4/6 inhibitor and immune check point inhibitor combination in patients with hormone receptor positive metastatic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 336.
Abstract 39: APOBEC3A drives acquired resistance to targeted therapies in non small cell lung cancer
Authors: Isozaki Hideko , Abbasi Ammal , Nikpour Naveed , Langenbucher Adam , Su Wenjia , Stanzione Marcello , Sequist Lecia V. , Buisson Rémi , Lawrence Michael S. , Hata Aaron N.
Published: July 2021

Acquired drug resistance to even the most effective anti cancer targeted therapies remains an unsolved clinical problem. Although many drivers of acquired drug resistance have been identified, the underlying molecular mechanisms shaping tumor evolution during treatment are incompletely understood. The extent to which therapy actively drives tumor evolution by promoting mutagenic processes or simply provides the selective pressure necessary for the outgrowth of drug resistant clones remains an open question. Here, we report that lung cancer targeted therapies commonly used in the clinic induce the expression of cytidine deaminase APOBEC3A (A3A), leading to sustained mutagenesis in drug tolerant cancer cells persisting during therapy. Induction of A3A facilitated the formation of double strand DNA breaks (DSBs) in cycling drug-treated cells, and fully resistant clones that evolved from drug tolerant intermediates exhibited an elevated burden of chromosomal aberrations such as copy number alterations and structural variations. Preventing therapy induced A3A mutagenesis either by gene deletion or RNAi mediated suppression delayed the emergence of drug resistance. Finally, we observed accumulation of A3A mutations in lung cancer patients who developed drug resistance after treatment with sequential targeted therapies. These data suggest that induction of A3A mutagenesis in response to targeted therapy treatment may facilitate the development of acquired resistance in non small cell lung cancer. Thus, suppressing expression or enzymatic activity of A3A may represent a potential therapeutic strategy to prevent or delay acquired resistance to lung cancer targeted therapy.

Citation Format: Hideko Isozaki, Ammal Abbasi, Naveed Nikpour, Adam Langenbucher, Wenjia Su, Marcello Stanzione, Lecia V. Sequist, Rémi Buisson, Michael S. Lawrence, Aaron N. Hata. APOBEC3A drives acquired resistance to targeted therapies in non small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 39.