Anticancer agent 223

Cytotoxicity assays are usually based on the assessment of cell membrane damage, which can also be indirectly detected by measuring cell viability. Detection methods include MTT assay, CKK-8 assay, LDH assay and ATP assay, etc.

Live/dead viability and cytotoxicity staining assays are based on the simultaneous detection of intracellular esterase activity in metabolically active (viable) cells and membrane integrity loss in non-viable cells. In commonly used dual-staining approaches, membrane-permeant fluorogenic substrates are converted by intracellular esterases into fluorescent products in live cells, while impermeant DNA-binding dyes selectively enter cells with compromised plasma membranes and label nucleic acids in dead or dying cells, enabling discrimination between viable and non-viable populations by fluorescence microscopy or flow cytometry.

Suspension spheroid formation by low-adhesion or forced aggregation is a scaffold-free 3D culture method in which cells are prevented from attaching to plastic and are guided to interact with each other, forming compact multicellular aggregates through cell-cell adhesion, gravity-driven settling, microwell confinement, or centrifugation-assisted aggregation. The method detects the capacity of a cell population to self-assemble into spheroids, and the main readouts are spheroid formation efficiency, morphology, compactness, projected area or diameter, circularity, viability, proliferation, and experimental responses such as drug sensitivity. Classic implementations include hanging drops, agarose or hydrogel microwells, ultra-low-attachment round-bottom wells, and centrifugation-assisted aggregation in non-adherent wells. Low-adhesion culture shifts the system away from cell-substrate adhesion and toward cell-cell adhesion, while round-bottom or microwell geometry concentrates cells into

Apoptosis is a regulated, generally non-lytic cell-death pathway that removes unwanted, damaged, infected, or abnormal cells through coordinated morphological changes, caspase activation, DNA fragmentation, and membrane remodeling. The intrinsic apoptosis pathway is controlled mainly by mitochondrial outer membrane permeabilization, BCL-2 family proteins, cytochrome c release, apoptosome formation, caspase-9 activation, and downstream executioner caspase-3/7 activation. The extrinsic apoptosis pathway is initiated by death receptors such as Fas, TNFR, and TRAIL receptors, which recruit adaptor proteins and activate caspase-8 before engaging executioner caspases or mitochondrial amplification through BID cleavage. Apoptosis is linked to many phenotypes, including cancer cell killing, tissue homeostasis, immune regulation, neurodegeneration, infection response, and treatment-induced cytotoxicity; unresolved questions include how apoptosis interacts with necroptosis, pyroptosis, ferroptos

Hanging drop spheroid culture is a scaffold-free 3D culture method in which a small droplet of cell suspension is inverted so that suspended cells sediment by gravity toward the lowest point of the drop, aggregate, and form a multicellular spheroid with direct cell-cell contact. Spheroids generated by this method are used to study 3D cell cohesion, cell-ECM interactions, drug response, co-culture organization, and tumor-like microenvironmental behavior. The primary readouts are spheroid formation efficiency, spheroid size, circularity or compactness, viability, and treatment response; these can be measured by bright-field microscopy, fluorescence viability staining, ATP-, fluorescence-, or colorimetric-based assays, and image-based diameter or volume calculations.