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Influence of growth phase, nutrition and hypoxia on heterogeneity of cellular buoyant densities in in vitro tumor model systems
Author(s) -
Luk Catherine K.,
Sutherland Robert M.
Publication year - 1986
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910370614
Subject(s) - isopycnic , percoll , monolayer , spheroid , biophysics , biology , plateau (mathematics) , exponential growth , density gradient , chemistry , in vitro , centrifugation , biochemistry , physics , mathematical analysis , mathematics , quantum mechanics
EMT6/Ro multicellular spheroids were sequentially dissociated into outer, middle and inner layers, and the buoyant densities of these subpopulations were compared to aerobic or exponential or plateau‐phase monolayers by isopycnic density centrifugation using Percoll as the gradient medium. Spheroids were more heterogeneous in buoyant density distributions than monolayer cultures. The outer‐layer cells of spheroids and fed plateau monolayers peaked at a similar density; the majority of middle‐layer cells banded close to unfed plateau and exponential hypoxic monolayers, while most inner‐layer cells banded where fed or unfed plateau hypoxic monolayer peaked in density. Our data suggest that metabolic heterogeneity due to growth phase, together with altered cellular microenvironment brought about by differences in oxygenation and external nutrient supplies between spheroids and monolayers, can be manifested in one biophysical parameter such as buoyant density.