Proliferation-associated oxygen consumption and morphology of tumor cells in monolayer and spheroid culture.
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 cellular oxygen uptake. Despite a continuous decrease of cell proliferation from the surface to interior regions of EMT6 spheroids reflected by a gradient in tritiated thymidine labeling, volume-related oxygen consumption is rather uniform in viable regions of these aggregates. The finding can be explained by the results of the morphometric evaluation showing a uniform volume density of mitochondria, i.e., of oxygen-consuming sites within these spheroids.
Bredel-Geissler
A
A
Institute of Physiology and Pathophysiology, University of Mainz, Germany.
Karbach
U
U
Walenta
S
S
Vollrath
L
L
Mueller-Klieser
W
W
D000818:Animals; D002455:Cell Division / Q000502:physiology*; D007700:Kinetics; D015674:Mammary Neoplasms, Animal / Q000378:metabolism / Q000648:ultrastructure*; D051379:Mice; D008854:Microscopy, Electron; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology*; D012509:Sarcoma / Q000378:metabolism / Q000648:ultrastructure*; D014407:Tumor Cells, Cultured
D010100:Oxygen