Aggressive Breast Cancer Cell Lines Research Articles

The influence of the chlorine atom on the biological activity of 2′-hydroxychalcone in relation to the lipid phase of biological membranes - Anticancer and antimicrobial activity

The study investigates the effect of the presence of a chlorine atom in the 2′-hydroxychalcone molecule on its interaction with model lipid membranes, in order to discern its potential pharmacological activity. Five chlorine derivatives of 2′-hydroxychalcone were synthesized and evaluated against liposomes composed of POPC and enriched with cationic (DOTAP) or anionic (POPG) lipids. The physicochemical properties of the compounds were initially simulated using SwissAdame software, revealing high lipophilicity (ilogP values: 2.79–2.90). The dynamic light scattering analysis of liposomes showed that chloro chalcones induce minor changes in the diameter of liposomes of different surface charges. Fluorescence quenching assays with a TMA-DPH probe demonstrated the strong ability of the compounds to interact with the lipid bilayer, with varying quenching capacities based on chlorine atom position. FTIR studies indicated alterations in carbonyl, phosphate, and choline groups, suggesting a transition area localization rather than deep penetration into the hydrocarbon chains. Additionally, dipole potential reduction was observed in POPC and POPC-POPG membranes, particularly pronounced by derivatives with a chlorine atom in the B ring. Antibacterial and antibiofilm assays revealed enhanced activity of derivatives with a chlorine atom compared to 2′-hydroxychalcone, especially against Gram-positive bacteria. The MIC and MBIC50 values showed increased efficacy in the presence of chlorine with 3′-5′-dichloro-2′-hydroxychalcone demonstrating optimal antimicrobial and antibiofilm activity. Furthermore, antiproliferative assays against breast cancer cell lines indicated higher activity of B-ring chlorine derivatives, particularly against MDA-MB-231 cells. In general, the presence of a chlorine atom in 2′-hydroxychalcone improves its pharmacological potential, with derivatives showing improved antimicrobial, antibiofilm, and antiproliferative activities, especially against aggressive breast cancer cell lines. These findings underscore the importance of molecular structure in modulating biological activity and highlight chalcones with a chlorine as promising candidates for further drug development studies.

MCT4 knockdown by tumor microenvironment-responsive nanoparticles remodels the cytokine profile and eradicates aggressive breast cancer cells

Breast cancer is a wide-spread threat to the women’s health. The drawbacks of conventional treatments necessitate the development of alternative strategies, where gene therapy has regained hope in achieving an efficient eradication of aggressive tumors. Monocarboxylate transporter 4 (MCT4) plays pivotal roles in the growth and survival of various tumors, which offers a promising target for treatment. In the present study, pH-responsive lipid nanoparticles (LNPs) based on the ionizable lipid,1,2-dioleoyl-3-dimethylammonium propane (DODAP), were designed for the delivery of siRNA targeting MCT4 gene to the breast cancer cells. Following multiple steps of characterization and optimization, the anticancer activities of the LNPs were assessed against an aggressive breast cancer cell line, 4T1, in comparison with a normal cell line, LX-2. The selection of the helper phospholipid to be incorporated into the LNPs had a dramatic impact on their gene delivery performance. The optimized LNPs enabled a powerful MCT4 silencing by ∼90 % at low siRNA concentrations, with a subsequent ∼80 % cytotoxicity to 4T1 cells. Meanwhile, the LNPs demonstrated a 5-fold higher affinity to the breast cancer cells versus the normal cells, in which they had a minimum effect. Moreover, the MCT4 knockdown by the treatment remodeled the cytokine profile in 4T1 cells, as evidenced by 90 % and ∼64 % reduction in the levels of TNF-α and IL-6; respectively. The findings of this study are promising for potential clinical applications. Furthermore, the simple and scalable delivery vector developed herein can serve as a breast cancer-targeting platform for the delivery of other RNA therapeutics.

Abstract 6772: A 3D model of breast cancer-bone metastasis to mimic dysregulation of bone remodeling and drug response

Abstract Introduction: Bone metastases are common among advanced stage breast cancer patients and induce dysregulation of bone remodeling. Crosstalk between cancer cells and the bone niche drives the vicious cycle of bone loss and breast cancer growth. To accelerate discovery of targeted therapies, there is a critical need for experimental models that can mimic breast cancer-induced dysregulation of bone remodeling in patients. Mouse models are the current gold standard, but are low throughput, costly, and cannot fully recapitulate human-human cell interactions. To address these limitations, our goal is to engineer a fully human 3D in vitro model of breast cancer-bone metastasis that can mimic dysregulation of bone remodeling and drug responses in patients, and enable screening of potential new drug candidates. Methods: Two human breast cancer cell lines (MDA-MB-231, MCF-7) were chosen given their well characterized clinical features and tendency to invade bone. Our 3D model comprises an outer ring of tissue engineered (TE) bone and a center of breast cancer cells to mimic invasion through the bone marrow/long bone interface. Human mesenchymal stem cells were encapsulated in 3D gelatin microribbon scaffolds and cultured in osteogenic media for 28 days to form TE bone. Human monocyte-derived osteoclasts were seeded onto the bone, and the center was replaced with GFP-labeled breast cancer cells. Denosumab and zoledronic acid were selected as they are standard treatments for reducing bone loss in patients, and were used to treat the model at 30 µg/mL and 2 µg/mL, respectively. Intermittent parathyroid hormone (iPTH) treatment was selected as it showed efficacy in animal models, and was used to treat the model at 10 µg/mL for 6 hours daily. All groups were treated with drugs for 14 days. Bone volume was assessed using microCT. Cancer cell proliferation and invasion into bone was monitored with fluorescence confocal microscopy. Results: MicroCT imaging showed both breast cancer cell lines induced bone loss in the triculture model, compared to the control with no breast cancer cells in the center. Consistent with known clinical features, the more aggressive cell line (MDA-MB-231) induced a greater amount of bone loss than the less aggressive breast cancer cell line (MCF-7). Consistent with clinical findings, both denosumab and zoledronic acid reduced bone loss in our 3D model, and zoledronic acid further reduced breast cancer cell invasion and proliferation. Finally, the 3D model recapitulated the in vivo drug response of iPTH treatment, reducing bone resorption and breast cancer invasion. Conclusions: Here we report a fully human triculture model of breast cancer-bone metastasis that can mimic key clinical features of breast cancer-induced bone resorption and drug response in patients. Such a 3D model could enable screening of drug candidates with reduced time and cost and enable identification of novel druggable targets. Citation Format: Michelle Tai, Eva C. González Díaz, Callan E. Monette, Joy Wu, Fan Yang. A 3D model of breast cancer-bone metastasis to mimic dysregulation of bone remodeling and drug response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6772.

Abstract 3385: Modeling evolutionary fitness in resistant cancers based on a common adaptability trait

Abstract Cancer is composed of a major subpopulation of proliferative cells and a minor subpopulation of highly adaptable cells. Although it is evident that cancer is an evolution like process driven by rare adaptable cancer cells that persist under various selection pressures, most of our knowledge about cancer comes from studying proliferative cancer cells. To overcome the hurdle in modeling adaptable cancer cell state that defeats all currently offered therapies, we are exploiting a linkage that exists between different adaptability substates such as metabolic, regulatory, and structural substates. Our studies, thus far carried out with aggressive triple-negative breast cancer and melanoma cell lines, suggest that it is feasible to apply severe metabolic challenges as realistic selection pressures/bottlenecks for modeling highly abnormal and highly adaptable cancer cells that drive cancer evolution and therapy resistance. The most significant aspect of our approach is an ability to model rare resistant cells (approximately 0.01% of cells) that survive in reversible quiescence under selection pressures. Monitoring of cells under microscope for several weeks under a severe and prolonged metabolic challenge, for example, a lack of glutamine in culture medium, revealed perhaps most interesting and cancer-relevant cells that survive in quiescence for weeks and then advance to generate therapy-resistant cells. Such microscopic monitoring revealed a significant heterogeneity among surviving cells. As examples, 1) surviving cells differ in the depth of quiescence, some cells trying to proliferate sooner than others; 2) as cells progress from quiescence to proliferation, their fate is far from certain: cells may progress to yield few cells, tiny colony, or large colony and then stop proliferating and in most instances die (abortive attempts at evolution). Of significance, the cell lines derived inflammatory breast cancer (IBC), an aggressive subtype of breast cancer, possessed a higher evolutionary fitness than non-IBC cell lines. This approach also eliminates 99.99% of cells that proliferate in cell culture but would not survive selection pressures in the body. The adaptable cells that survived the bottleneck and then proliferated indefinitely were highly resistant and metastatic. Molecular analyses of adaptable cells, including gene expression microarrays, CGH microarrays, and whole genome sequencing revealed mechanisms for their plasticity (exemplified by markers of high EMT), and for generating cellular diversity by altering epigenome (exemplified by low TET2) and by structural modifications in transcriptome (exemplified by high FTO). We conclude that the phenotype-based approach described here is good at modeling deep intrinsic resistance and may be useful in developing strategies for improving outcomes in resistant cancers. Supported by a State of Texas Grant for Rare and Aggressive Cancers. Citation Format: Balraj Singh, Vanessa N. Sarli, Anthony Lucci. Modeling evolutionary fitness in resistant cancers based on a common adaptability trait [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3385.

177Lu-Labeled Iron Oxide Nanoparticles Functionalized with Doxorubicin and Bevacizumab as Nanobrachytherapy Agents against Breast Cancer.

The use of conventional methods for the treatment of cancer, such as chemotherapy or radiotherapy, and approaches such as brachytherapy in conjunction with the unique properties of nanoparticles could enable the development of novel theranostic agents. The aim of our current study was to evaluate the potential of iron oxide nanoparticles, coated with alginic acid and polyethylene glycol, functionalized with the chemotherapeutic agent doxorubicin and the monoclonal antibody bevacizumab, to serve as a nanoradiopharmaceutical agent against breast cancer. Direct radiolabeling with the therapeutic isotope Lutetium-177 (177Lu) resulted in an additional therapeutic effect. Functionalization was accomplished at high percentages and radiolabeling was robust. The high cytotoxic effect of our radiolabeled and non-radiolabeled nanostructures was proven in vitro against five different breast cancer cell lines. The ex vivo biodistribution in tumor-bearing mice was investigated with three different ways of administration. The intratumoral administration of our functionalized radionanoconjugates showed high tumor accumulation and retention at the tumor site. Finally, our therapeutic efficacy study performed over a 50-day period against an aggressive triple-negative breast cancer cell line (4T1) demonstrated enhanced tumor growth retention, thus identifying the developed nanoparticles as a promising nanobrachytherapy agent against breast cancer.

Abstract B039: Butyrate and propionate-reduced oncogenic phenotypes in triple-negative breast cancer

Abstract Objectives Triple negative breast cancer (TNBC) is the most aggressive form of breast cancer affecting 5% of all patients with no known treatment. Hispanic women show a higher risk of developing this type of cancer at an early age. Heterogeneity of TNBC between patients makes it challenging to devolop a effective treatment. The compostion of microbiome amongst the patients has a high variablity that could affect the production of the microbial products. The changes in microbial products have not been previously evaluated and could possibly contribute to chronic inflammation in the patients. Short-chain fatty acids (SCFA), i.e. butyrate, acetate, and propionate which are metabolical products of the microbiome that can potentially inhibit cell growth, proliferation and migration of cancer cells, may represent an alternative treatment for TNBC. Here, we measured the impact of SCFAs treament on viability and migration of MDA-231 cell lines. Methods MDA-231 cell line is an aggressive triple-negative breast cancer (TNBC) cell line common for evaluating new therapeutic strategies. MDA-231 cells were cultured in RPMI-1640 medium supplemented with 10% fetal bovine serum and we evaluated oncogenic phenotypes (cell viability and migration) after SCFA treatment. Cells were treated with butyrate, acetate, and propionate in cell culture media at seven concentrations starting at 125mM (1:2 dilution factor) for 24, 48 and 72 hours (h). We determined the cell viability using Alamar blue and determined the half-maximal inhibitory concentration (IC50) after SCFA treatment at all time points. Furthermore, we performed a wound-healing assay for 24h to evaluate the impact of SCFA on cell migration. MDA-231 cells were cultured to a 100% confluency and a scratch was performed in the cell monolayer to create an artificial gap, simulating the wound. Immediately after performing the wound, the cells were treated with SCFA at concentrations of 1mM and 5mM. Results Higher concentrations of butyrate and propionate reduced cell viability for MDA-231 was reduced. Particularly, butyrate showed an IC50 at 24h, 48h and 72h of 4.7mM, 4.34 mM and 3.6mM, respectively. However, propionate showed an IC50 only at 48h and 72h of 21.09 mM and 19.5 mM, respectively. There was no impact in cell viability after acetate treatment. In relation to migration, MDA-231 cell lines treated with butyrate and propionate at 5mM show a slower migration rate at 24h when compared to the untreated cells. Conclusions Our results suggest that butyrate and propionate can reduce oncogenic phenotypes in MDA-231. Future work will measure the impact of SCFA on cell proliferation, motility, and epithelial-mesenchymal transition. SCFAs may represent a promising target for novel treatment strategies for TNCB. Citation Format: Liah M Román-Calderón, Ariana S García-López, Jeannette L Salgado-Montilla, Gabriel Borges-Vélez, Esther A Peterson-Peguero, Josué Pérez-Santiago. Butyrate and propionate-reduced oncogenic phenotypes in triple-negative breast cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr B039.

Integrative Modulation of Magnetic Resonance Transverse and Longitudinal Relaxivity in a Cell-Viable Bimagnetic Ensemble, γ-Fe2O3@ZnFe2O4.

The potential application of magnetic nanosystems as magnetic resonance imaging (MRI) contrast agents has been thoroughly investigated. This work seeks to attain robust MRI-contrast efficiency by designing an interacting landscape of a bimagnetic ensemble of zinc ferrite nanorods and maghemite nanoparticles, γ-Fe2O3@ZnFe2O4. Because of competing spin clusters and structural anisotropy triggered by isotropic γ-Fe2O3 and anisotropic ZnFe2O4, γ-Fe2O3@ZnFe2O4 undergoes the evolution of cluster spin-glass state as evident from the critical slowing down law. Such interacting γ-Fe2O3@ZnFe2O4 with spin flipping of 1.2 × 10-8 s and energy barrier of 8.2 × 10-14 erg reflects enhanced MRI-contrast signal. Additionally, γ-Fe2O3@ZnFe2O4 is cell-viable to noncancerous HEK 293 cell-line and shows no pro-tumorigenic activity as observed in MDA-MB-231, an extremely aggressive triple-negative breast cancer cell line. As a result, γ-Fe2O3@ZnFe2O4 is a feasible option for an MRI-contrast agent having longitudinal relaxivity, r1, of 0.46 s-1mM-1 and transverse relaxivity, r2, of 15.94 s-1mM-1, together with r2/r1 of 34.65 at 1.41 T up to a modest metal concentration of 0.1 mM. Hence, this study addresses an interacting isotropic/anisotropic framework with faster water proton decay in MR-relaxivity resulting in phantom signal amplification.

Preliminary anticancer evaluation of new Pd(II) complexes bearing NNO donor ligands

In this study we presented a novel series of NNO tridentate ligands generating imino, amido and oxo donor pocket for Pd(II) coordination. All the compounds were meticulously characterized by elemental analysis and advanced spectroscopic techniques, including FTIR, proton and carbon NMR. The synthesized compounds underwent rigorous evaluation for their potential as anti-cancer agents, utilizing the aggressive breast cancer cell lines MDA-MB (ATCC) and MCF-7 as a crucial model for assessing growth inhibition in cancer cells. Remarkably, the MTT assay unveiled the robust anti-cancer activity for all palladium complexes against MDA-MB-231 and MCF-7 cells. Particularly, complex [Pd(L1)(CH3CN)] exhibited exceptional potency with an IC50 value of 25.50 ± 0.30 µM (MDA-MB-231) and 20.76 ± 0.30 µM (MCF-7), compared to respective 27.00 ± 0.80 µM and 24.10 ± 0.80 µM for cisplatin, underscoring its promising therapeutic potential. Furthermore, to elucidate the mechanistic basis for the anti-cancer effects, molecular docking studies on tyrosine kinases, an integral target in cancer research, were carried out. The outcome of these investigations further substantiated the remarkable anticancer properties inherent to these innovative compounds. This research offers a compelling perspective on the development of potent anti-cancer agents rooted in the synergy between ligands and Pd(II) complexes and presenting a promising avenue for future cancer therapy endeavors.

Super-resolution microscopy reveals the nanoscale cluster architecture of the DEK protein cancer biomarker

DEK protein, a key chromatin regulator, is strongly overexpressed in various forms of cancer. While conventional microscopy revealed DEK as uniformly distributed within the cell nucleus, advanced super-resolution techniques uncovered cluster-like structures. However, a comprehensive understanding of DEK's cellular distribution and its implications in cancer and cell growth remained elusive. To bridge this gap, we employed single-molecule localization microscopy (SMLM) to dissect DEK's nanoscale organization in both normal-like and aggressive breast cancer cell lines. Our investigation included characteristics such as localizations per cluster, cluster areas, and intra-cluster localization densities (ICLDs). We elucidated how cluster features align with different breast cell types and how chromatin decompaction influences DEK clusters in these contexts. Our results indicate that DEK's intra-cluster localization density and nano-organization remain preserved and not significantly influenced by protein overexpression or chromatin compaction changes. This study advances the understanding of DEK's role in cancer and underscores its stable nanoscale behavior.

Inhibitor titrations reveal low control of glyceraldehyde 3-phosphate dehydrogenase and high control of hexokinase on glycolytic flux in an aggressive triple-negative breast cancer cell line

The glycolytic flux, and in particular lactate production, is strongly increased in cancer cells compared to normal cells, a characteristic often referred to as aerobic glycolysis or the Warburg effect. This makes the glycolytic pathway a potential drug target, in particular if the flux control distribution in the pathway has shifted due to the metabolic reprogramming in cancer cells. The flux response of a drug is dependent on both the sensitivity of the target to the drug and the flux control of the target, and both these characteristics can be exploited to obtain selectivity for cancer cells. Traditionally drug development programs have focused on selective sensitivity of the drug, not necessarily focussing on the flux control of the target. We determined the flux control of two steps that have been suggested to have high control in cancer cells, using two inhibitors, iodoacetic acid and 3-bromopyruvate, and measured a flux control of the glyceraldehyde 3-phosphate dehydrogenase close to zero, while the hexokinase holds 50% of all flux control in glycolysis in an invasive cancer cell line MDA-mb-231.

Urtica dioica Leaf Infusion Enhances the Sensitivity of Triple-Negative Breast Cancer Cells to Cisplatin Treatment.

Urtica dioica (UD) has been widely used in traditional medicine due to its therapeutic benefits, including its anticancer effects. Natural compounds have a promising potential when used in combination with chemotherapeutic drugs. The present study explores the anticancer and anti-proliferative properties of UD tea in combination with cisplatin on MDA-MB-231 breast cancer cells in vitro. To elucidate the effect of this combination, a cell viability assay, Annexin V/PI dual staining, cell death ELISA, and Western blots were performed. The results showed that the combination of UD and cisplatin significantly decreased the proliferation of MDA-MB-231 cells in a dose- and time-dependent manner compared to each treatment alone. This was accompanied by an increase in two major hallmarks of apoptosis, the flipping of phosphatidylserine to the outer membrane leaflet and DNA fragmentation, as revealed by Annexin V/PI staining and cell death ELISA, respectively. DNA damage was also validated by the upregulation of the cleaved PARP protein as revealed by Western blot analysis. Finally, the increase in the Bax/Bcl-2 ratio further supported the apoptotic mechanism of death induced by this combination. Thus, a leaf infusion of Urtica dioica enhanced the sensitivity of an aggressive breast cancer cell line to cisplatin via the activation of apoptosis.

Abstract 3704: The essential role of an alternate mRNA translation initiation in the regulation of breast cancer cell metabolism

Abstract Translational control and metabolic reprogramming are hallmarks of advanced cancers. Important genes involved in cancer progression express mRNAs that are selectively translated, including regulators of cancer cell metabolism. Cancer cells acquire an altered metabolism, switching from oxidative phosphorylation (OXPHOS) to a glycolytic phenotype (Warburg effect), to increase reliance on alternate metabolic pathways to support growth, proliferation, and metastasis. Triple-negative breast cancer (TNBC), one of the most aggressive and highly metastatic subtypes with the poorest outcome, is characterized by elevated glycolysis and low OXPHOS. Still, the exact mechanism for this metabolic switch is largely unknown. Using a TNBC cell model it has been shown an alternate mechanism of cap-dependent but mTORC1/eIF4Eindependent mRNA translation by the eIF4G homolog, DAP5, which directly binds the cap-binding protein eIF3d. Our research indicates that this alternate translation initiation is essential in regulating several mRNAs involved in breast cancer metabolism. DAVID analysis from genome-wide transcriptomic and translatomic studies, metabolomic assays including Glycolysis Assay [Extracellular Acidification], Oxidative Phosphorylation, and Mitotracker Assay, as well as RT-PCR and western blot analysis was performed from well-characterized triple-negative aggressive breast cancer cell lines,4T1 and MDA-231, Non-silencing (Nsi) control and silencing DAP5 (shDAP5) samples. Several mRNAs related to glucose metabolism decreased after silencing DAP5 and on the opposite, critical mRNAs associated with OXPHOS increased, independent of their steady-state mRNA abundance. Silencing DAP5 increased Oxidative Phosphorylation activity and decrease the glycolytic rate in TNBC breast cancer cells. Proteins correlated with aberrant glycolytic metabolism including the E-cadherin transcriptional repressors Snail (SNAI1) were reduced after silencing of DAP5. Our data indicates that the alternate mRNA translation initiation mechanism by DAP5 of specific mRNAs correlated to glycolysis and OXPHOS could play an essential role in the mechanism by which TNBC breast cancer cells orchestrate a metabolic switch required for malignant progression and metastasis. Citation Format: Hanna Rosenstock, Erna Mitaishvili, Columba de la Parra. The essential role of an alternate mRNA translation initiation in the regulation of breast cancer cell metabolism. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3704.

Development and evaluation of a java-based deep neural network method for drug response predictions.

Accurate prediction of drug response is a crucial step in personalized medicine. Recently, deep learning techniques have been witnessed with significant breakthroughs in a variety of areas including biomedical research and chemogenomic applications. This motivated us to develop a novel deep learning platform to accurately and reliably predict the response of cancer cells to different drug treatments. In the present work, we describe a Java-based implementation of deep neural network method, termed JavaDL, to predict cancer responses to drugs solely based on their chemical features. To this end, we devised a novel cost function and added a regularization term which suppresses overfitting. We also adopted an early stopping strategy to further reduce overfit and improve the accuracy and robustness of our models. To evaluate our method, we compared with several popular machine learning and deep neural network programs and observed that JavaDL either outperformed those methods in model building or obtained comparable predictions. Finally, JavaDL was employed to predict drug responses of several aggressive breast cancer cell lines, and the results showed robust and accurate predictions with r 2 as high as 0.81.

The Chorioallantoic Membrane Xenograft Assay as a Reliable Model for Investigating the Biology of Breast Cancer

The chorioallantoic membrane (CAM) assay is an alternative in vivo model that allows for minimally invasive research of cancer biology. Using the CAM assay, we investigated phenotypical and functional characteristics (tumor grade, mitosis rate, tumor budding, hormone receptor (HR) and HER2 status, Ki-67 proliferation index) of two breast cancer cell lines, MCF-7 and MDA-MB-231, which resemble the HR+ (luminal) and triple-negative breast cancer (TNBC) subgroups, respectively. Moreover, the CAM results were directly compared with murine MCF-7- and MDA-MB-231-derived xenografts and human patient TNBC tissue. Known phenotypical and biological features of the aggressive triple-negative breast cancer cell line (MDA-MB-231) were confirmed in the CAM assay, and mouse xenografts. Furthermore, the histomorphological and immunohistochemical variables assessed in the CAM model were similar to those in human patient tumor tissue. Given the confirmation of the classical biological and growth properties of breast cancer cell lines in the CAM model, we suggest this in vivo model to be a reliable alternative test system for breast cancer research to reduce murine animal experiments.

Antimigratory Evaluation from Curcumin-Derived Synthetic Compounds PGV-1 and CCA-1.1 on HCC1954 and MDA-MB-231 Cells

Earlier findings reported the anticancer-mediated activities of curcumin-modified compounds Pentagamavunone-1 (PGV-1) and Chemoprevention Curcumin Analog 1.1 (CCA-1.1) with several mechanisms including cell cycle arrest, reactive oxygen species (ROS) production, and cell migration disruption. Our study aims to evaluate the antimigratory activity of PGV-1 and CCA-1.1 on aggressive breast cancer cell lines (MDA-MB-231 and HCC1954 cells) and their effect on HER2 protein. The trypan blue exclusion method was conducted for the antiproliferative effect. The PGV-1 or CCA-1.1 effect on cell migration was determined by wound healing assay. Using gelatin zymography, we checked the secretion level of matrix metalloproteinase (MMP). We also evaluated the human epidermal growth receptor-2 (HER2) level after incubation with PGV-1 or CCA-1.1 in HCC1954 cells by western blot. Based on the antiproliferation assay, MDA-MB-231 and HCC1954 cells were sensitive to PGV-1 and CCA-1.1. MMP-2 was only observed in HCC1954 cells while MMP-9 was only observed in MDA-MB-231. Both PGV-1 and CCA-1.1 significantly suppressed MMP-9 activity in MDA-MB-231 cells. Moreover, PGV-1 inhibited HER2 protein levels in HCC1954 although it was not significant, whereas CCA-1.1 did not affect HER2 protein. This study strengthens the scientific evidence for PGV-1 and CCA-1.1 activities for future exploration as candidate chemotherapy with multitarget against breast cancer.Keywords: Curcumin analog, cell migration, MMP-9, HER2, breast cancer.

Subcellular analysis of nuclear and cytoplasmic redox indices differentiates breast cancer cell subtypes better than nuclear-to-cytoplasmic area ratio.

.SignificanceStratification of malignancy is valuable for cancer treatment. Both optical redox imaging (ORI) indices and nuclear-to-cytoplasmic volume/area ratio (N:C ratio) have been investigated to differentiate between cancers with varying aggressiveness, but these two methods have not been directly compared. The redox status in the cell nucleus has not been studied by ORI, and it remains unknown whether nuclear ORI indices add new biological information.AimWe sought to compare the capacity of whole-cell and subcellular ORI indices and N:C ratio to differentiate between breast cancer subtypes with varying aggressiveness and between mitotic and nonmitotic cells.ApproachORI indices for whole cell, cytoplasm, and nucleus as well as the N:C area ratio were generated for two triple-negative (more aggressive) and two receptor-positive (less aggressive) breast cancer cell lines by fluorescence microscopy.ResultsWe found positive correlations between nuclear and cytoplasmic ORI indices within individual cells. On average, a nuclear redox status was found to be more oxidized than cytoplasm in triple-negative cells but not in receptor-positive cells. Whole-cell and subcellular ORI indices distinguished between the receptor statuses better than the N:C ratio. However, N:C ratio was a better differentiator between nonmitotic and mitotic triple-negative cells.ConclusionsSubcellular ORI analysis differentiates breast cancer subtypes with varying aggressiveness better than N:C area ratio.

Abstract 424: Development of HJC0152-based proteolysis-targeting chimera degraders for breast cancer therapy

Abstract Signal transducer and activator of transcription 3 (STAT3), a member of the STAT family, is constitutively activated in various human cancers, and has been recognized as an attractive therapeutic target in cancer. STAT3 protein dimerizes and translocates to the nucleus to eventually transactivate downstream target genes. Despite some progress has been made in the past two decades, to date there is still lack of FDA-approved STAT3 inhibitors available for clinical use. Recently, proteolysis-targeting chimera (PROTAC) technology has dramatically advanced the development of therapeutics by introducing targeted protein degradation. Previously, our team has developed HJC0152, a promising STAT3 inhibitor, via structure- and fragment-based drug design strategies and in silico molecular modeling and docking. HJC0152 has demonstrated an attractive cancer therapeutic and preventive efficacy by targeting the non- estrogen receptor (ER)-based STAT3 signaling pathway. To achieve better potency and inhibition of STAT3 signaling, we therefore developed a series of HJC0152-based PROTAC protein degraders. These potential anticancer agents have been initially evaluated and several showed favorable potency in inhibiting the proliferation in a panel of breast cancer cell lines. We found that compounds JMX1122, JMX1123, and JMX1124 significantly inhibited proliferation and colony formation of a highly aggressive triple-negative breast cancer (TNBC) cell line, MDA-MB-231, and the ER-positive breast cancer cell lines. Different from the lead compound HJC0152, which showed an early inhibition on the phosphorylation of STAT3 at the Tyr705 and Ser727 residues, the newly developed HJC0152-PROTACs showed a significantly late differential inhibition of STAT3 phosphorylation at the Tyr705 and Ser727 residues, and reduced the total STAT3 protein level at 72 hours of treatment. Our current results support the notion that HJC0152-based PROTAC degraders potently suppress breast cancer cell proliferation and induce apoptosis, via direct targeting of STAT3 and its protein degradation. These compounds are currently being investigated for breast cancer cell migration and invasion, and will be evaluated for the in vivo inhibition of tumor growth and metastasis in different mouse models. This project is supported by NIH/NCI Awards R01CA226001 and R01CA231150 to Q.S. and J.Z. Citation Format: Junhai Xu, Jimin Xu, Ruixia Ma, Mingxiang Zhou, Doerte R. Fricke, Haiying Chen, Hyejin Kim, Xi Liu, Jia Zhou, Qiang Shen. Development of HJC0152-based proteolysis-targeting chimera degraders for breast cancer therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 424.

Abstract 108: Insulin-like growth factor binding protein 4 exerts differential effects on breast cancer cell proliferation based on the expression status of pregnancy-associated plasma protein A

Abstract Insulin-Like Growth Factor Binding Protein 4 (IGFBP-4) is one of six binding proteins involved in sequestering insulin-like growth factors 1 and 2 (IGFs). IGFBP-4 expression is induced by estrogen receptor α (ERα), and its classical function is to prevent activation of IGF-1 receptor (IGF-1R) by sequestration of IGF-1. However, the aggressive triple-negative breast cancer cell line MDA-MB-231 shows high expression of IGFBP-4 along with its protease, pregnancy-associated plasma protein A (PAPP-A). Further, inhibition of IGFBP-4 in MDA-MB-231 cells is sufficient to reduce migration. To better understand the function of IGFBP-4 as a pro-cancer or anti-cancer protein, its anti-proliferative effects in ERα positive cells must be reconciled with its pro-migratory effects in triple negative cells. The role of IGFBP-4 in proliferation across four breast cancer cell lines representing ERα positive and triple negative subtypes was investigated. Stable transfection with IGFBP-4 expression construct in the MCF-7 and T-47D cell lines, which have silenced the PAPP-A gene, shows a reduction in proliferation. Further, MCF-7 parental cells cultured in conditioned media containing IGFBP-4 also show reduced proliferation, suggesting that the anti-proliferative effect of IGFBP-4 is associated with the absence of PAPP-A. Stable IGFBP-4 transfection of triple-negative MDA-MB-468 cell line, which has low extracellular IGFBP-4 when compared to MDA-MB-231 but does express PAPP-A, was sufficient to increase proliferation. Taken together, these results support the conclusion that proliferative effects of IGFBP-4 are dependent upon the expression status of PAPP-A. Citation Format: Keenan L. Flynn, Kevin D. Houston. Insulin-like growth factor binding protein 4 exerts differential effects on breast cancer cell proliferation based on the expression status of pregnancy-associated plasma protein A [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 108.

Density-Dependent Migration Characteristics of Cancer Cells Driven by Pseudopod Interaction.

The ability of cancer cells to invade neighboring tissue from primary tumors is an important determinant of metastatic behavior. Quantification of cell migration characteristics such as migration speed and persistence helps to understand the requirements for such invasiveness. One factor that may influence invasion is how local tumor cell density shapes cell migration characteristics, which we here investigate with a combined experimental and computational modeling approach. First, we generated and analyzed time-lapse imaging data on two aggressive Triple-Negative Breast Cancer (TNBC) cell lines, HCC38 and Hs578T, during 2D migration assays at various cell densities. HCC38 cells exhibited a counter-intuitive increase in speed and persistence with increasing density, whereas Hs578T did not exhibit such an increase. Moreover, HCC38 cells exhibited strong cluster formation with active pseudopod-driven migration, especially at low densities, whereas Hs578T cells maintained a dispersed positioning. In order to obtain a mechanistic understanding of the density-dependent cell migration characteristics and cluster formation, we developed realistic spatial simulations using a Cellular Potts Model (CPM) with an explicit description of pseudopod dynamics. Model analysis demonstrated that pseudopods exerting a pulling force on the cell and interacting via increased adhesion at pseudopod tips could explain the experimentally observed increase in speed and persistence with increasing density in HCC38 cells. Thus, the density-dependent migratory behavior could be an emergent property of single-cell characteristics without the need for additional mechanisms. This implies that pseudopod dynamics and interaction may play a role in the aggressive nature of cancers through mediating dispersal.

MitoQ Inhibits Human Breast Cancer Cell Migration, Invasion and Clonogenicity.

Simple SummarySolid tumors comprise metabolically hostile areas adjacent to metabolically friendly ones, and their distribution fluctuates in space and time. Selection pressure is maximal in hostile areas where cancer cells develop at least four survival strategies: to adapt themselves, to modify the microenvironment, to hibernate metabolically, and to escape. Escape marks the transition from a localized to an invasive tumor that may ultimately disseminate remotely, forming metastases. Based on the hypothesis that mitochondria are metabolic sensors that control these responses, we previously established that mitochondrial superoxide is a pro-metastatic intracellular signaling agent. Here, we tested MitoQ, a mitochondria-targeted ROS inactivator that already successfully passed Phase I safety clinical trials, as a potential inhibitor of the early steps of the metastatic cascade. Using human breast cancer cells as models in anticipation of preclinical and clinical assays, we report that MitoQ inhibits cancer cell migration, invasion, clonogenicity, sphere formation and spheroid stability.To successfully generate distant metastases, metastatic progenitor cells must simultaneously possess mesenchymal characteristics, resist to anoïkis, migrate and invade directionally, resist to redox and shear stresses in the systemic circulation, and possess stem cell characteristics. These cells primarily originate from metabolically hostile areas of the primary tumor, where oxygen and nutrient deprivation, together with metabolic waste accumulation, exert a strong selection pressure promoting evasion. Here, we followed the hypothesis according to which metastasis as a whole implies the existence of metabolic sensors. Among others, mitochondria are singled out as a major source of superoxide that supports the metastatic phenotype. Molecularly, stressed cancer cells increase mitochondrial superoxide production, which activates the transforming growth factor-β pathway through src directly within mitochondria, ultimately activating focal adhesion kinase Pyk2. The existence of mitochondria-targeted antioxidants constitutes an opportunity to interfere with the metastatic process. Here, using aggressive triple-negative and HER2-positive human breast cancer cell lines as models, we report that MitoQ inhibits all the metastatic traits that we tested in vitro. Compared to other mitochondria-targeted antioxidants, MitoQ already successfully passed Phase I safety clinical trials, which provides an important incentive for future preclinical and clinical evaluations of this drug for the prevention of breast cancer metastasis.