Resilience has recently emerged as a security priority, but the development of mission resilience analysis techniques for military systems has lagged behind those for other systems. This paper identifies gaps for mission resilience assessment in current vulnerability assessment approaches used at military facilities. Additionally, the paper describes ongoing research to develop a set of mission resilience models that addresses those gaps and could be used to evaluate mission resilience to electric power outages.
The transcription factor β-catenin is a key player in many cellular processes, including stem cell renewal, cellular homeostasis and inflammation. Deregulation of β-catenin occurs frequently in several cancer types by mutation or overexpression of the β-catenin gene or mutation of negative regulators such as Adenomatous Polyposis Coli (APC). ST316 is a novel peptide antagonist that specifically interferes with the association of β-catenin with its co-activator BCL9, disrupting β-catenin nuclear localization and attenuating target gene expression. In an orthotopic triple-negative breast cancer (TNBC) model, ST316 demonstrates potent anti-tumor activity, resulting in 84% tumor growth inhibition (TGI) (p<0.001 vs. vehicle control). In addition to its cell-autonomous mechanisms, deregulated Wnt/β-catenin signaling can promote tumorigenesis by impacting the tumor microenvironment. Reprogramming of immunosuppressive M2-like Tumor Associated Macrophages (TAMs) toward an immune-promoting program (M1-like) is an attractive cancer immunotherapeutic strategy. Here we explored ST316 potential for macrophage repolarization toward the M1-like phenotype, activation of cytotoxic T-cells in macrophage/T-cell co-culture assays and cooperation of ST316 with anti-PD-1 to enhance anti-tumor activity in vivo. Initial studies demonstrate that human macrophages derived from Peripheral Blood Mononuclear Cells (hPBMCs) and subsequently committed to the M2-like identity are reprogrammed toward an M1-like phenotype upon ST316 exposure. ST316 treatment dose-dependently suppressed expression of the M2 marker CD163 by flow cytometry and quantitative PCR, resulting in 100-fold increase in the M1/M2 ratio without substantial impact on cell viability. Importantly, T-cell viability and activation markers associated with M1-state (CD80, CD86) were not affected by ST316 at the concentrations used in these studies. Further, in co-cultures of M2 macrophage with T cells, ST316 exposure resulted in a three-fold increase in T-cell activation compared to control M2/T cell co-cultures, as measured by intracellular IFN-γ staining. Finally, in an orthotopic TNBC model in vivo, subtherapeutic ST316 enhanced the anti-tumor activity of anti-PD-1 [85% TGI with combination, compared to 51% TGI with anti-PD1 alone (p<0.01) and -9% TGI with subtherapeutic ST316 alone (p<0.001)]. Anti-tumor activity was accompanied by an increase the M1/M2 ratio. Overall, these results support the immuno-therapeutic potential of ST316 and extend the application range of ST316 to include Wnt-driven cancers with poor clinical response to immune checkpoint blockade and other immunotherapeutic agents. Citation Format: Claudio Scuoppo, Lila Ghamsari, Erin Gallagher, Siok Leong, Mark Koester, Rick Ramirez, Jerel Gonzales, Gene Merutka, Barry Kappel, Abi Vainstein-Haras, Jim Rotolo. Immunotherapeutic potential of ST316, a peptide antagonist of β-catenin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB016.
Anti-apoptotic B cell lymphoma 2 (Bcl-2) family proteins are frequently overexpressed across a variety of tumors, resulting in tumor cell survival and resistance to therapy. Inhibition of the expression or activity of these survival factors is an attractive approach for cancer therapy. Activating transcription factor 5 (ATF5) regulates gene transcription of anti-apoptotic Bcl-2 family proteins in neural progenitor cells and a wide range of human cancer cells. Here, we describe ST101, a rationally designed, synthetic, D-amino acid, cell penetrating peptide therapeutic designed to disrupt the protein-protein interactions driving ATF5-regulated gene transcription. Exposure of HL60 promyelocytic leukemia cells and MCF7 breast adenocarcinoma cells to low micromolar concentration of ST101 resulted in a decrease in MCL-1, BCL-2 and BIRC5 (Survivin) mRNA expression at 4 and 24 hrs post exposure. Further, exposure to ST101 resulted in a dose-dependent loss of viability across a panel of human cancer cells, including MCF7, HL60, U251 glioblastoma, A375 melanoma, DU145 prostate cancer, and A549 lung adenocarcinoma, characterized by an increase in annexin V and PI staining by flow cytometry peaking 48 hrs post exposure, resulting in a median half maximal effective concentration (EC50) value of 4.0 micromolar. In contrast, normal human peripheral blood mononuclear cells and bone marrow mononuclear cells were resistant to ST101-mediated cell death, with >80 micromolar EC50 values. In mouse xenograft experiments, 25mg/kg ST101 administered three times per week for three weeks resulted in significant tumor regression in MCF7 and U251 subcutaneous tumors as well as tumor growth delay in HL60 subcutaneous tumors. Tumor growth remained significantly inhibited weeks after the last treatment in the MCF7 and U251 models. In summary, ST101 selectively kills cancer cell lines by decreasing BCL-2 family gene expression, resulting in significant reductions in tumor growth in mouse models. Taken together, these data validate ST101 as a potent peptide therapeutic candidate for a variety of solid tumor and hematologic malignancies. Citation Format: Jim A. Rotolo, Rick Ramirez, Mark Koester, Siok Leong, Lila Ghamsari, Gene Merutka, Barry J. Kappel. Cell penetrating peptide, ST101, disrupts ATF5 regulation of anti-apoptotic Bcl-2 family proteins, resulting in induction of cancer cell death in vitro and tumor growth inhibition/regression in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2050.
Transcription factor dysregulation is common in cancer, resulting in aberrant gene expression that drives oncogenesis. Antagonism of oncogenic transcription factor activity, by disrupting essential protein-protein interactions needed for activation of downstream effector molecules or association with DNA, represents a powerful approach to target this previously ‘undruggable' class of proteins. CCAAT/Enhancer Binding Protein Beta (C/EBPβ) is a transcription factor overexpressed in many cancers that regulates expression of factors that promote tumor survival, proliferation and inhibit differentiation. Here, we decribe the anti-tumor activity of ST101, a cell-penetrating peptide antagonist of C/EBPβ. To demonstrate ST101 disruption of the interaction of C/EBPβ with co-factor activating transcription factor 5 (ATF5), a competition ELISA assay was performed. Recombinant ATF5 associated with plate-bound C/EBPβ with a binding affinity of ∼1 nM. Addition of ST101 inhibited this interaction in dose-dependent manner, resulting in an IC50 of 25 nM. To demonstrate ST101 disruption of C/EBPβ phosphorylation and gene transactivation in cancer cells, western blot analysis and quantitative polymerase chain reaction (qPCR) were performed on U251 glioblastoma, MCF7 breast adenocarcinoma and A549 lung adenocarcinoma cells. Administration of ST101 resulted in a dose-dependent decrease in C/EBPβ activation, as evidenced by a decrease in Thr189 phosphorylation. Anatgonism of C/EBPβ activity resulted in a dose-dependent decrease in mRNA expression of genes involved in survival (BCL2 and the baculoviral inhibitor of apoptosis factors BIRC3, BIRC5), inhibition of differentiation (Inhibitor of DNA binding proteins ID1, ID2 and ID3) and proliferation (cyclins CCNB1 and CCNA2 and cyclin-dependent kinases CDK1 and CDK2). Finally, in a mouse xenograft model, 25mg/kg ST101 administered three times per week for three weeks resulted in significant and sustained tumor growth inhibition in U251 subcutaneous tumors, both when ST101 administration was initiated early (day 2, 200 mm3 tumors, p<0.05) or late (day 16, >500mm3 tumors, p<0.05). These data demonstrate the therapeutic potential of systemic administration of ST101 and support clinical development of ST101 as a potent peptide therapeutic for a variety of solid tumor malignancies. Citation Format: Jim A. Rotolo, Rick Ramirez, Mark Koester, Erin Gallagher, Siok Leong, Lila Ghamsari, Gene Merutka, Barry J. Kappel. C/EBPβ antagonist peptide, ST101, attenuates oncogenic gene transactivation in cancer cells to drive antitumor activity [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 1817.
Aberrant activation of the canonical Wnt signaling pathway occurs in a variety of cancers, resulting in overactivation of β-catenin-mediated transcriptional activity and increased expression of genes that promote tumor survival, proliferation and inhibit differentiation. Disruption of the β-catenin transcription complex, by inhibiting protein-protein interactions required for its formation, represents a powerful approach to inhibit this previously ‘undruggable' target. The goal of these experiments is to characterize the anti-tumor activity of β-catenin antagonist peptides, BCA1 and BCA2, designed to disrupt the β-catenin transcription complex, in breast cancer models. In in vitro experiments, MCF7 (HER2neg/HRpos) breast adenocarcinoma cells were exposed to β-catenin antagonist peptides, and the impact on β-catenin-mediated gene transactivation was determined by quantitative polymerase chain reaction (qPCR). Results indicate that β-catenin antagonist peptide attenuated oncogenic gene transactivation in MCF7 cells, significantly decreasing the expression of direct β-catenin target genes including Myc, Cyclin D1 and Cyclin-dependent kinase 4 (p<0.05). The impact of β-catenin antagonist peptides on cancer cell viability was quantified by annexin V/PI flow cytometry analysis, indicating a dose-dependent decrease in overall cell viability 48 hours post peptide exposure. Additionally, BCA1 was administered to primary breast cancer tumoroids (HER2pos/HRneg or HER2neg/ HRneg), and the impact on tumoroid viability was quantified by histology and immunofluorescence microscopy. β-catenin antagonist peptide BCA1 resulted in dose-dependent decrease in surviving HER2pos/HRneg and HER2neg/ HRneg breast cancer tumoroids, with EC50 values of 5.2 and 6.9 µM, respectively. Finally, the impact of BCA2, an analogue of BCA1 with an additional N-terminal modification, on subcutaneous MCF7 xenograft tumors was determined in vivo. Administration of 5 mg/kg BCA2 via subcutaneous injection at a dosing frequency of 3x/week for 3 weeks resulted in 18-day tumor regression from the start of treatment and a 63.1% tumor growth inhibition compared to vehicle-treated controls (p<0.05). Taken together, these data demonstrate the significant anti-breast cancer activity of β-catenin antagonist peptides in vitro and in vivo. Citation Format: Jim A. Rotolo, Lila Ghamsari, Erin Gallagher, Rick Ramirez, Mark Koester, Siok Leong, Gene Merutka, Barry J. Kappel. β-catenin antagonist peptide attenuates oncogenic gene transactivation and promotes antitumor activity in breast cancer models [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 1816.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.