22-(4′-py)-JA

The spheroid/tumor organoid invasion assay measures outward movement of cancer cells from a compact 3D aggregate into an extracellular matrix, usually collagen I, basement membrane matrix, or mixed collagen-Matrigel hydrogels; the readout is generated by bright-field, fluorescence, confocal, or time-lapse imaging of cell egress, invasion area, invasion distance, dispersion, protrusion formation, basement-membrane perforation, or cell trajectories. The assay reflects cell-cell cohesion, cell-matrix adhesion, matrix remodeling, protease-dependent invasion, contractility, and invasion behavior in a 3D microenvironment rather than migration on a flat 2D surface.

Ex vivo organotypic tissue slice cultures are based on maintaining thin, viable tissue sections at an air-liquid interface to preserve native cytoarchitecture and local cell-matrix interactions, enabling observation of cell behavior such as migration and tissue infiltration within a physiologically relevant 3D microenvironment. The method relies on maintaining tissue viability on porous membrane supports, allowing diffusion of nutrients and oxygen while preserving structural integrity for extended culture periods, which makes it suitable for studying dynamic cellular processes in intact tissue contexts such as cell movement and tissue remodeling. .

Patient-derived organoid (PDO) invasion assays are based on the ability of epithelial tumor organoids to self-organize in three-dimensional extracellular matrix (ECM) hydrogels (commonly Matrigel) and to recapitulate key aspects of in vivo tissue architecture, including polarity, proliferation, and invasive outgrowth when exposed to permissive microenvironmental cues. In this system, invasion is operationally defined as the emergence of multicellular protrusions, collective budding, or single-cell dissemination from the organoid core into the surrounding ECM, reflecting epithelial-mesenchymal plasticity and matrix remodeling capacity. Organoid morphology and invasive behavior are typically monitored using brightfield or confocal microscopy over time, enabling quantitative assessment of invasion area, protrusion number, and structural disruption of the organoid spheroid architecture.

Mitochondrial membrane potential fluorescent assays estimate ΔΨm in living cells using lipophilic cationic dyes such as TMRM, TMRE, rhodamine 123, and JC-1, which accumulate in mitochondria according to membrane polarization; loss of signal after FCCP or CCCP treatment is interpreted as mitochondrial depolarization. TMRM/TMRE and rhodamine 123 are commonly used for semi-quantitative live-cell microscopy or flow cytometry, while JC-1 can report a shift from red aggregate fluorescence to green monomer fluorescence during depolarization; interpretation requires controls because dye concentration, quenching mode, cell type, dye efflux, and mitochondrial mass can affect fluorescence independently of ΔΨm.

3D tumor spheroid invasion assay measures outward tumor-cell movement from a compact multicellular spheroid into a surrounding extracellular matrix, producing image-based readouts such as invasion area, invasion distance, cell dispersion, or time-resolved cell movement. The method models tumor-cell interaction with matrix components in three dimensions and is used to study invasive phenotypes in cancer models including glioblastoma, squamous cell carcinoma, breast cancer, prostate cancer, ovarian cancer, and other solid tumor systems.

Matrigel Transwell/Boyden chamber invasion assay measures the ability of cells to degrade or traverse an extracellular matrix-coated porous membrane and move from an upper chamber toward a chemoattractant in a lower chamber. Invasion is distinguished from migration by coating the membrane with Matrigel or basement membrane matrix; uncoated inserts measure migration, while coated inserts require cells to cross an ECM barrier before reaching the underside of the membrane.

Invadopodia/fluorescent gelatin degradation assay detects proteolytic extracellular matrix degradation by cancer-cell invadopodia, which are actin-rich protrusive structures associated with matrix remodeling, invasion, and metastasis. The readout is generated by culturing cells on fluorescent gelatin and measuring dark degraded areas where fluorescent substrate has been locally removed, often together with immunofluorescent detection of invadopodia markers such as F-actin, cortactin, and TKS5.

Endothelial tube formation assay evaluates the ability of endothelial cells to attach, migrate, align, and organize into capillary-like networks when cultured on gelled basement membrane extract or Matrigel; the readout is the morphology and quantity of tube-like networks, which reflects an in vitro endothelial morphogenesis step related to angiogenesis. Basement membrane extract/Matrigel provides laminin-rich extracellular matrix cues that support endothelial differentiation into capillary-like structures, but it can contain biologically active growth factors, so growth-factor-reduced matrix is preferred when testing defined angiogenic stimulators or inhibitors.

Mitochondrial membrane potential staining measures the electrochemical polarization across the mitochondrial inner membrane in live cells using lipophilic cationic fluorescent probes; early rhodamine-based work showed that selective mitochondrial dye accumulation is lost when the mitochondrial transmembrane potential is dissipated. JC-1 reports mitochondrial polarization by shifting from green monomer fluorescence to red J-aggregate fluorescence as dye concentration increases within energized mitochondria; therefore, the red/green fluorescence ratio is used as a relative readout of mitochondrial membrane potential. TMRE or TMRM staining provides a single-channel relative readout because these cationic rhodamine esters accumulate in polarized mitochondria, and lower fluorescence indicates reduced mitochondrial polarization when acquisition and dye-loading conditions are controlled. Mitochondrial mass staining is commonly performed with MitoTracker Green FM or related MitoTracker dyes as

The organotypic 3D invasion assay measures carcinoma-cell invasion into a fibroblast-remodeled extracellular matrix, usually collagen I with or without basement-membrane matrix, under an air-liquid or grid-supported culture condition; the readout is invasion depth, invaded area, or an invasion index from histological or fluorescence images. This assay models stromal regulation of invasion because fibroblasts or CAFs remodel matrix, generate tracks, and can lead collective carcinoma-cell invasion; the resulting cancer-cell penetration into the gel reflects tumor-stroma-ECM interactions rather than migration on a rigid 2D substrate.

Cell invasion is the ability of cells to migrate from one area to another via the extracellular matrix. Cell invasion is the response of normal and cancer cells to chemical and mechanical stimuli. Before migrating to a new region, the extracellular matrix is degraded by proteases within the cell. Cell invasion often occurs during wound repair, vascularization and inflammation, abnormal tissue invasion, and tumor cell metastasis.

The Matrigel/ECM Transwell invasion assay measures the ability of cells to move toward a chemoattractant while crossing an extracellular-matrix barrier placed on a porous membrane; therefore, the readout reflects both chemotactic motility and matrix invasion rather than migration alone. Matrigel is a basement-membrane-rich matrix derived from Engelbreth-Holm-Swarm mouse sarcoma and has been used as a reconstituted basement membrane barrier in chemoinvasion assays. The assay readout is generated by quantifying cells that reach the underside of the insert membrane or lower compartment after incubation, commonly by staining and counting invaded cells or by fluorescence-based quantification.

The glioma/brain tumor 3D invasion assay measures outward migration and matrix invasion from multicellular tumor spheroids into a 3D extracellular matrix or organotypic brain slice. The readout is generated by time-lapse brightfield, fluorescence, confocal, or high-content imaging and quantified as invasion distance, invasion area, migration index, single-cell velocity, directionality, cumulative sprout length, or Z-direction invasion into brain tissue. Classic in vitro versions embed glioma or GBM spheroids in collagen I, Matrigel, collagen I/Matrigel, or collagen I/Matrigel/hyaluronic acid matrices, while ex vivo versions implant fluorescent GBM spheroids onto organotypic brain slices to model invasion in a preserved brain microenvironment.

The 3D collagen/hydrogel matrix invasion assay is based on embedding cells within or on top of a three-dimensional fibrillar extracellular matrix (typically type I collagen or collagen-rich hydrogels) to model cell migration through a physiologically relevant physical barrier. In this system, invasive behavior is quantified by measuring the ability of cells to degrade, remodel, and migrate through the 3D matrix architecture, which better reflects in vivo tissue invasion compared to 2D migration assays. Collagen-based 3D matrices provide structural cues such as fiber alignment and porosity that influence cell motility and integrin-mediated adhesion, enabling observation of collective or single-cell invasion modes depending on matrix density and organization.