Biology subjects

Jerabkova-Roda, K.

Publications and source records attributed to Jerabkova-Roda, K..

3 recordsLinked to original sources

bioRxiv2026

Quantitative Mapping of Organelle Positioning in Cultured Cells Using Semi-Automated Image Analysis Pipeline

Subcellular architecture is tightly controlled and contributes to the maintenance of cells homeostasis. Organelles are regulated in size, shape, number and position which respond to changes in extracellular environment. Lysosomes are of particular interest as they integrate various functions in the cells (nutrient sensing, metabolism, cell migration and adhesion), serving as signaling hubs. Their function is tightly linked to their subcellular position and deregulation of lysosome homeostasis leads to several diseases including cancer. Therefore, methods allowing precise analysis of organelle subcellular distribution can aid in fundamental, diagnostic and therapeutic approaches. Here, we provide a versatile image analysis pipeline using ImageJ and CellProfiler. This workflow allows to quantify subcellular lysosome distribution in living and fixed melanoma cells, and is applicable to other subcellular compartments and to various cell types.

cell biology↗

bioRxiv2026

Selective targeting of RalA with intrabodies impairs Triple Negative Breast Cancer metastasis

This study successfully developed and validated isoform-specific intrabodies targeting the highly homologous Ral oncoproteins, key effectors in cancer progression. Phage display was used to isolate single-chain variable fragment (scFv) clones that recognize specifically RalA (C1-A, G5-A), RalB (F6-B), or both paralogs (A12-AB). Using lentiviral transduction, these intrabodies were stably expressed as GFP fusions in murine breast cancer 4T1 cells. The anti-RalA clones C1-A and A12-AB demonstrated clear colocalization with RalA, confirming their binding activity inside the cell. We further confirmed their activity in cells by analyzing Ral-dependent pathways. All intrabodies targeting RalA (C1-A, G5-A, A12-AB) but not the one specific to RalB inhibited mitochondrial fission, a known RalA function. All clones, except the pan-Ral one, altered the endo-lysosome pathway by decreasing lysosome number. Furthermore, the RalA-specific C1-A clone reduced lysosomes size, and uniquely and strongly reduced extracellular vesicle secretion, highlighting its distinct inhibitory potential. In an orthotopic Triple-Negative Breast Cancer (TNBC) mouse model, The C1-A RalA specific clone significantly but weakly reduced primary tumor growth, but exerted a powerful anti-metastatic effect, dramatically reducing lung metastases, with a complete abolition of metastases observed in 2/5 mice. In summary, these potent, isoform-specific Ral intrabodies act as effective intracellular inhibitors, successfully modulating RalA-specific functions in cells and offering a promising therapeutic strategy for significantly suppressing tumor growth and metastasis in vivo.

cancer biology↗

bioRxiv2023

Peripheral positioning of lysosomes supports melanoma aggressiveness

Emerging evidences suggest that function and position of organelles are pivotal for tumor cell dissemination. Among them, lysosomes stand out as they integrate metabolic sensing with gene regulation and secretion of proteases. Yet, how their function is linked to their position and how this controls metastasis remains elusive. Here, we analyzed lysosome subcellular distribution in patient-derived melanoma cells and patient biopsies and found that lysosome spreading scales with their aggressiveness. Peripheral lysosomes promote matrix degradation and invasion of melanoma cells which is directly linked to their lysosomal and cell transcriptional programs. When controlling lysosomal positioning using chemo-genetical heterodimerization in patient-derived melanoma cells, we demonstrated that perinuclear clustering impairs lysosomal secretion, matrix degradation and invasion. Impairing lysosomal spreading in two distinct in vivo models (mouse and zebrafish) significantly reduces invasive outgrowth. Our study provides a direct demonstration that lysosomal positioning controls cell invasion, illustrating the importance of organelle adaptation in carcinogenesis and suggesting that lysosome positioning could potentially be used for the diagnosis of metastatic melanoma.

cell biology↗