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Posligua Garcia, J. D.

Publications and source records attributed to Posligua Garcia, J. D..

2 recordsLinked to original sources

Dynamic Tracking and Single-Cell Analysis of Starvation-Induced Autophagic Responses in Breast Cancer Cells

Nutrient stress induces dynamic and heterogeneous cellular responses that are often reduced to population averages or endpoint measurements. AURORA is a longitudinal single-cell phenotyping framework integrating high-content time-lapse imaging, trajectory-aware quality control, multi-compartment morphology, reference phenotypic states, and cross-cell-line aggregation of state-occupancy behaviors. AURORA is applied to MCF-7, MDA-MB-231, A-549, and HT-1080 cancer cells during 4 h exposure to Earle's balanced salt solution (EBSS). Population-level Total Autophagy shows sustained EBSS-associated elevation in MCF-7, A-549, and HT-1080, but a stronger early response followed by attenuation in MDA-MB-231. Longitudinal analysis shows that these averages arise from cell-line- and time-dependent changes in single-cell distributions rather than uniform displacement. Feature-level analysis further identifies distinct combinations of nuclear, whole-cell, and autophagosome-associated organization, compactness, and shape in each model. Projection of EBSS-treated cells into Complete-defined phenotypic landscapes reveals line-specific redistribution among reference states. Despite this specificity, dominant state-occupancy signatures converge into six recurrent higher-order programs, linking different cellular routes to partially shared remodeling architectures. Because DAPGreen is not paired with a flux inhibitor or ratiometric reporter, these findings describe an autophagy-associated imaging phenotype rather than autophagic flux. AURORA therefore distinguishes population-average change from heterogeneous single-cell adaptation during dynamic stress responses.

cancer biology↗

Hydroxyurea induces ER stress and cytoplasmic protein aggregation

The endoplasmic reticulum (ER) lumen provides the proper redox environment for disulfide bond formation, which is required for the appropriate folding of proteins that enter the secretory pathway and constitute membranes. Defective protein folding in the ER activates proteostatic mechanisms that are now beginning to be elucidated. Here, we show that hydroxyurea (HU) causes ER stress and triggers a transient perinuclear ER expansion, which leads to the clustering of nuclear pore complexes. This striking phenotype is mimicked by diamide (DIA), a specific thiol stress inductor, and prevented or rapidly reverted by dithiothreitol, a dithiol-reducing agent, suggesting that ER expansion is caused by disulfide stress. ER expansion induced by HU or DIA depends on glutathione (GSH), is Ire1-independent, and is associated with a unique transcriptome program that differs from the canonical unfolding protein response (UPR). The ER luminal expansion accumulates Hsp70 Bip1 chaperone, and it evolves parallel with the appearance of cytoplasmic protein aggregates containing heat stress proteins (HSPs), indicating that both HU and DIA are impinging on protein folding. Thus, our data reveal that HU induces disulfide stress that impinges on protein folding in the cytoplasm and ER.

cell biology↗