Search results for "Spheroid"

Proliferation-associated oxygen consumption and morphology of tumor cells in monolayer and spheroid culture.

1992

The oxygen consumption rate, proliferative activity, and morphology of EMT6/Ro mouse mammary sarcoma cells in monolayer and multicellular spheroid culture have been investigated in a comparative study. During the transition of monolayer cells from the exponential into the plateau growth phase, there is a distinct decrease in the cellular volume that is associated with a corresponding decrease in the proliferative and respiratory activity of the cells. The decline in cell volume is mainly due to a decrease in the content of cytoplasm, whereas the size of the nucleus is only slightly reduced. A concomitant decrease in the number of mitochondria per cell obviously accounts for the reduction in…

Glutathione content of V79 cells in two- or three-dimensional culture

1997

The cellular glutathione (GSH) content of two- and three-dimensional cell cultures of V79 hamster lung cells has been studied. As previously described, cells in monolayer cultures show a decrease in GSH when they reach the confluent state. Three-dimensional cell cultures (multicell spheroids) allow a smoother transition from the initial proliferating to the nonproliferating status, and they show a central area of necrosis when a certain diameter is reached. Cellular GSH content in spheroids is variable throughout the culturing period: 1) GSH content (expressed per mg protein) is lower in spheroids with central necrotic areas than in smaller spheroids without necrosis, and 2) results expres…

Three-dimensional cell cultures: from molecular mechanisms to clinical applications.

1997

This article reviews actual advances in the development and application of three-dimensional (3-D) cell culture systems. Recent therapeutically oriented studies include characterization of multicellular-mediated drug resistance, novel ways of quantifying hypoxia, and new approaches to more efficient immunotherapy. Recent progress toward understanding the development of necrosis in tumor spheroids has been made using novel spheroid models. 3-D cultures have been used for studies on molecular mechanisms involved in invasion and metastasis, with a major focus on the role of E-cadherin. Similarly, tumor angiogenesis and the significance of vascular endothelial growth factor have been investigat…

Oxygen Consumption and Oxygen Diffusion Properties of Multicellular Spheroids from two Different Cell Lines

1984

Multicellular spheroids are an in vitro tissue model in which the cells are supplied by diffusion of oxygen and substrates from the environmental growth medium (Sutherland et al., 1971). Since these substances are consumed when diffusing to the spheroid center, their concentration should decrease continuously towards the inner parts of the spheroids. Therefore, the location of the cells within the spheroid is an important determinant of the efficiency of the O2 and nutrient supply. The restriction of the O2 availability in the inner part of the spheroids may influence the metabolic and cell cycle state, and may even cause cell death, indicated by central necrosis in larger spheroids. Also, …

Size-Dependent Oxygenation and Energy Status in Multicellular Tumor Spheroids

1990

Multicellular tumor spheroids show numerous analogies to tumor microregions in vivo, such as the development of central necrosis at a certain spheroid size (for reviews see: Mueller-Klieser, 1987; Sutherland, 1988). The histological structure of the cell aggregates suggests that diffusion limitation of oxygen or nutrients in spheroids may cause cell death in the innermost parts of the spheroids. However, measurements with oxygen-sensitive microelectrodes are indicative of necrosis arising in the presence of relatively high oxygen tension (PO2) values, as they were found in normal tissue (Carlsson and Acker, 1985; Mueller-Klieser et al., 1986). Although still controversial in literature, rec…

Differential changes in purine nucleotides after Doxorubicin treatment of human cancer cells in vitro

2002

The present investigation was performed to elucidate the role of purine nucleotides as potential indicators of chemosensitivity of malignant tumors. Drug-sensitive (s) and -resistant (r) tumor cell lines grown as monolayers (s: T47D, MCF-7 wild-type; r: NCI/ADR-RES, MCF-7/MDR) or as multicellular spheroids (T47D; NCI/ADR-RES) were exposed to 0.1, 1.0, and 10.0 microM Doxorubicin for up to 24 h. Purine nucleotides were assayed using HPLC and with some selected spheroids using imaging bioluminescence. The data show that in the time frame of the experiments reproducible and statistically significant changes in the nucleotides only occur at the highest drug concentration investigated. Under the…

Changes in the Transcriptome Profiles of Human Amnion-Derived Mesenchymal Stromal/Stem Cells Induced by Three-Dimensional Culture: A Potential Primin…

2022

Mesenchymal stromal/stem cells (MSCs) are believed to function in vivo as a homeostatic tool that shows therapeutic properties for tissue repair/regeneration. Conventionally, these cells are expanded in two-dimensional (2D) cultures, and, in that case, MSCs undergo genotypic/phenotypic changes resulting in a loss of their therapeutic capabilities. Moreover, several clinical trials using MSCs have shown controversial results with moderate/insufficient therapeutic responses. Different priming methods were tested to improve MSC effects, and three-dimensional (3D) culturing techniques were also examined. MSC spheroids display increased therapeutic properties, and, in this context, it is crucial…

Phake Intraokularlinsen

2004

Phakic intraocular lenses (PIOLs), which are located closer to the eye's nodal points than the anterior corneal surface, can provide superior optical quality for higher corrections because of retention of normal prolate corneal asphericity and larger effective optical zones. Improvements in the material and design of phakic intraocular lenses and their insertion devices combined with advances in the understanding of the anatomical and physiological interactions of the PIOLs with intraocular structures, have increased safety and efficacy. Safety of these implants over the long term remains a concern, but in several situations PIOLs are the refractive correction of choice. The purpose of this…

k-Carrageenan and PVA blends as 3D printing bioinks for cartilage reconstruction scaffolding

2021

Injectable hydrogel formulations to host adipose stem cell spheroids for stemness maintenance and bone and cartilage regeneration

2021

Adipose-derived mesenchymal stem cells (ASCs) represent a great promise for tissue regeneration as fat is a very abundant source of stem cells (1) and owing to their ability to self-renew and differentiate into specific tissue types (2). In general, they are usually cultured as two-dimensional (2D) adherent monolayers, not representative of the in vivo condition, often entailing lower cell viability and, more in general, a lower “cell quality” in terms of regenerative potential (3, 4). When ASCs are cultured in low adhesion flasks and with a suitable culture medium, they aggregate in the form of three-dimensional spheroids (SASCs). The incorporation of these spheroids into injectable, in-si…