BACKGROUND Necrosis, a type of cell death accompanied by the rupture of the plasma membrane, promotes tumor progression and aggressiveness by releasing the pro-inflammatory and angiogenic cytokine high mobility group box 1. It is commonly found in the core region of solid tumors due to hypoxia and glucose depletion (GD) resulting from insufficient vascularization. Thus, metabolic stress-induced...

Long-term culture and monitoring of individual multicellular spheroids and embryoid bodies (EBs) remains a challenge for in vitro cell propagation. Here, we used a continuous 3D projection printing approach - with an important modification of nonlinear exposure - to generate concave hydrogel microstructures that permit spheroid growth and long-term maintenance, without the need for spheroid tra...

A quiescent (nonproliferating) subpopulation was identified by flow cytometric analysis using two-step acridine orange staining in the EMT6/Rochester, N. Y. subline multicellular tumor spheroid, an in vitro culture system which provides a cellular microenvironment which mimics that of many of in vivo tumors. To isolate a viable quiescent cell subpopulation, centrifugal elutriation which allows ...

We consider emergent collective behavior of a multicellular biological system. Specifically, we investigate the role of hypoxia (lack of oxygen) in migration of brain tumor cells. We performed two series of cell migration experiments. In the first set of experiments, cell migration away from a tumor spheroid was investigated. The second set of experiments was performed in a typical wound-healin...

Enforced EGFR activation upon gene amplification and/or mutation is a common hallmark of malignant glioma. Small molecule EGFR tyrosine kinase inhibitors, such as erlotinib (Tarceva), have shown some activity in a subset of glioma patients in recent trials, although the reported data on the cellular basis of glioma cell responsiveness to these compounds have been contradictory. Here we have use...

The uptake of E -combretastatins, potential prodrugs of the anticancer Z -isomers, into multicellular spheroids has been imaged by intrinsic fluorescence in three dimensions using two-photon excited fluorescence lifetime imaging with 625-nm ultrafast femtosecond laser pulses. Uptake is initially observed at the spheroid periphery but extends to the spheroid core within 30 min. Using agarose gel...

A calcitonin (CT)-producing cell line (DMS53) established from human small cell carcinoma of the lung was grown as three-dimensional multicellular spheroids in spinner culture or on agar in multiwells, and as tumors in nude (athymic) mice. CT release into the media was directly proportional to spheroid volume. The response of these cells following exposures to X-irradiation, Adriamycin, or diaz...

We developed the double elution analysis technique, a modification of standard alkaline elution techniques, to assess cross-link formation and repair in the cycling and noncycling cell populations of multicellular spheroids. DNA cross-linking from cycling cells was measured using radioisotope incorporation; DNA cross-linking from the total cell population was estimated using a fluorometric meth...

Glandular epithelial cells differentiate into complex multicellular or acinar structures, when embedded in three-dimensional (3D) extracellular matrix. The spectrum of different multicellular morphologies formed in 3D is a sensitive indicator for the differentiation potential of normal, non-transformed cells compared to different stages of malignant progression. In addition, single cells or cel...

We developed the double elution analysis technique, a modification of standard alkaline elution techniques, to assess cross-link formation and repair in the cycling and noncycling cell populations of multicellular spheroids. DNA cross-linking from cycling cells was measured using radioisotope incorporation; DNA cross-linking from the total cell popu lation was estimated using a fluorometric met...