by Keyword: Lead
Liu, TY, De Pace, C, Huang, RD, Bruno, G, Shao, T, Tian, YP, Chen, B, Chen, L, Luo, K, Gong, QY, Ruiz-Pérez, L, Battaglia, G, Tian, XH, (2023). An Iridium (III) complex revealing cytoskeleton nanostructures under super-resolution nanoscopy and liquid-phase electron microscopy Sensors And Actuators B-Chemical 388, 133839
Live cell actin visualization is fundamental for exploring cellular motility, cytokinesis, intracellular transport, and other correlated functions. The current imaging techniques that allow imaging of actin in its native environment are optical and electron microscopy. Such imaging techniques offer high enough resolution to investigate the ultrastructure of actin however they come at the expense of actin integrity. Inspired by the lack of suitable probes that preserve actin's integrity, we designed a cyclometalated Ir (III) complex that interacts with live cells and displays light switch behaviour upon specific actin binding. The exceptional photophysical properties of the proposed probe allow unprecedented resolution of cytoskeleton ultrastructures under stimulated emission depletion (STED) super-resolution nanoscopy. Moreover, the Ir complex enables the capability of visualizing actin polymers and periodicity under correlative light electron microscopy (CLEM) and liquid-phase electron microscopy (LPEM) at similar to 8 nm resolution.
JTD Keywords: Actin dynamics, Actin targeting, Adhesion, Cells, Clem, Fluorescent, Iridium (iii) complex, Lead, Light, Lpem, Super-resolution ultrastructures
Hino, N, Matsuda, K, Jikko, Y, Maryu, G, Sakai, K, Imamura, R, Tsukiji, S, Aoki, K, Terai, K, Hirashima, T, Trepat, X, Matsuda, M, (2022). A feedback loop between lamellipodial extension and HGF-ERK signaling specifies leader cells during collective cell migration Developmental Cell 57, 2290-2304 
Upon the initiation of collective cell migration, the cells at the free edge are specified as leader cells; however, the mechanism underlying the leader cell specification remains elusive. Here, we show that lamellipodial extension after the release from mechanical confinement causes sustained extracellular signal-regulated kinase (ERK) activation and underlies the leader cell specification. Live-imaging of Madin-Darby canine kidney (MDCK) cells and mouse epidermis through the use of Förster resonance energy transfer (FRET)-based biosensors showed that leader cells exhibit sustained ERK activation in a hepatocyte growth factor (HGF)-dependent manner. Meanwhile, follower cells exhibit oscillatory ERK activation waves in an epidermal growth factor (EGF) signaling-dependent manner. Lamellipodial extension at the free edge increases the cellular sensitivity to HGF. The HGF-dependent ERK activation, in turn, promotes lamellipodial extension, thereby forming a positive feedback loop between cell extension and ERK activation and specifying the cells at the free edge as the leader cells. Our findings show that the integration of physical and biochemical cues underlies the leader cell specification during collective cell migration.Copyright © 2022 Elsevier Inc. All rights reserved.
JTD Keywords: activation, c-met, contact inhibition, focal adhesions, heparan-sulfate, mechanical forces, morphogenesis, rho, stress fibers, Collective cell migration, Erk, Feedback regulation, Fret, Growth-factor receptor, Hgf, Lamellipodia, Leader cell specification, Signal transduction, Traction force, Wound healing
Zañudo, JGT, Mao, PP, Alcon, C, Kowalski, K, Johnson, GN, Xu, GT, Baselga, J, Scaltriti, M, Letai, A, Montero, J, Albert, R, Wagle, N, (2021). Cell line-specific network models of er breast cancer identify potential pi3kainhibitor resistance mechanisms and drug combinations Cancer Research 81, 4603-4617
Durable control of invasive solid tumors necessitates identifying therapeutic resistance mechanisms and effective drug combinations. In this work, we used a network-based mathematical model to identify sensitivity regulators and drug combinations for the PI3Ka inhibitor alpelisib in estrogen receptor positive (ER) PIK3CAmutant breast cancer. The model-predicted efficacious combination of alpelisib and BH3 mimetics, for example, MCL1 inhibitors, was experimentally validated in ER breast cancer cell lines. Consistent with the model, FOXO3 downregulation reduced sensitivity to alpelisib, revealing a novel potential resistance mechanism. Cell line-specific sensitivity to combinations of alpelisib and BH3 mimetics depended on which BCL2 family members were highly expressed. On the basis of these results, newly developed cell line-specific network models were able to recapitulate the observed differential response to alpelisib and BH3 mimetics. This approach illustrates how network-based mathematical models can contribute to overcoming the challenge of cancer drug resistance.
JTD Keywords: activation, akt, feedback, foxo, leads, p27(kip1), phosphorylation, reveals, transcription factors, Dependent kinase inhibitor
Conti, S, Kato, T, Park, D, Sahai, E, Trepat, X, Labernadie, A, (2021). CAFs and cancer cells co-migration in 3D spheroid invasion assay Methods In Molecular Biology 2179, 243-256
© 2020, Springer Science+Business Media, LLC, part of Springer Nature. In many solid tumors, collective cell invasion prevails over single-cell dissemination strategies. Collective modes of invasion often display specific front/rear cellular organization, where invasive leader cells arise from cancer cell populations or the tumor stroma. Collective invasion involves coordinated cellular movements which require tight mechanical crosstalk through specific combinations of cell–cell interactions and cell–matrix adhesions. Cancer Associated Fibroblasts (CAFs) have been recently reported to drive the dissemination of epithelial cancer cells through ECM remodeling and direct intercellular contact. However, the cooperation between tumor and stromal cells remains poorly understood. Here we present a simple spheroid invasion assay to assess the role of CAFs in the collective migration of epithelial tumor cells. This method enables the characterization of 3D spheroid invasion patterns through live cell fluorescent labeling combined with spinning disc microscopy. When embedded in extracellular matrix, the invasive strands of spheroids can be tracked and leader/follower organization of CAFs and cancer cells can be quantified.
JTD Keywords: 3d spheroid invasion, cancer associated fibroblasts, collective migration, dissemination, epithelial cancer cells, leader/follower cells, 3d spheroid invasion, Cancer associated fibroblasts, Collective invasion, Collective migration, Epithelial cancer cells, Leader/follower cells
Solà-Soler, J., Giraldo, B. F., (2020). Comparison of ECG-eerived respiration estimation methods on healthy subjects in function of recording site and subject position and gender Engineering in Medicine & Biology Society (EMBC) 
42nd Annual International Conference of the IEEE , IEEE (Montreal, Canada) , 2650-2653
Respiration rate can be assessed by analyzing respiratory changes of the electrocardiogram (ECG). Several methods can be applied to derive the respiratory signal from the ECG (EDR signal). In this study, four EDR estimation methods based on QRS features were analyzed. A database with 44 healthy subjects (16 females) in supine and sitting positions was analyzed. Respiratory flow and ECG recordings on leads I, II, III and a Chest lead was studied. A QR slope-based method, an RS slope-based method, an QRS angle-based method and an QRS area-based method were applied. Their performance was evaluated by the correlation coefficient with the reference respiratory volume signal. Significantly higher correlation coefficients in the range r = 0.77 – 0.86 were obtained with the Chest lead for all methods. The EDR estimation method based on the QRS angle provided the highest similarity with the volume signal for all recording leads and subject positions. We found no statistically significant differences according to gender or subject position.Clinical Relevance— This work analyzes the EDR signal from four electrocardiographic leads to obtain the respiratory signal and contributes to a simplified analysis of respiratory activity.
JTD Keywords: Electrocardiography, Lead, Estimation, Correlation coefficient, Databases, Heart, Correlation
Conti, S., Kato, T., Park, D., Sahai, E., Trepat, X., Labernadie, A., (2020). CAFs and cancer cells co-migration in 3D spheroid invasion assay Methods in Molecular Biology (ed. Campbell, K., Thevenea, E.), Humana Press (New York, USA) 2179, 243-256
In many solid tumors, collective cell invasion prevails over single-cell dissemination strategies. Collective modes of invasion often display specific front/rear cellular organization, where invasive leader cells arise from cancer cell populations or the tumor stroma. Collective invasion involves coordinated cellular movements which require tight mechanical crosstalk through specific combinations of cell–cell interactions and cell–matrix adhesions. Cancer Associated Fibroblasts (CAFs) have been recently reported to drive the dissemination of epithelial cancer cells through ECM remodeling and direct intercellular contact. However, the cooperation between tumor and stromal cells remains poorly understood. Here we present a simple spheroid invasion assay to assess the role of CAFs in the collective migration of epithelial tumor cells. This method enables the characterization of 3D spheroid invasion patterns through live cell fluorescent labeling combined with spinning disc microscopy. When embedded in extracellular matrix, the invasive strands of spheroids can be tracked and leader/follower organization of CAFs and cancer cells can be quantified.
JTD Keywords: 3D spheroid invasion, Cancer associated fibroblasts, Collective migration, Epithelial cancer cells, Leader/follower cells
