Abstract
A technique for exposing the interior of aggregates of cultured cells has been developed and is described in this report. Using this technique, we have examined for the first time, by scanning electron microscopy, cell morphology and cell contact ultrastructure in the interior of aggregates of BALB/c 3T3 and SV40-transformed 3T3 cells. The 3T3 cells make initial intercellular contact by means of microvillar processes. Over a period of 3-8 h, some of these microvillar contacts are replaced by broader projections. In contrast, the SV40-transformed cells make initial intercellular contact by means of blebs or blunt projections which are also broadened and extended over a period of 3-8 h. For both 3T3 and SV40-3T3 cells, the surfaces of the cells which form the outer layer of the aggregate resemble the surfaces of single cells fixed in suspension, regardless of how long the aggregates have been cultured. Thse cells are covered with many cellular processes and are roughly hemispherical in profile. The surfaces of the internal cells of the aggregates, however, lose many of their cellular processes, develop smooth patches, and many become irregular in shape. This smooth morphology was also observed on the interior surfaces of the peripheral cell layer. From these observations we conclude that: (a) the stabilization of adhesive contacts is a slow process which takes at least 3-8 h; (b) the outer surfaces of peripheral cells differ significantly from the surfaces of interior cells; and (c) clear differences in surface topography exist between nonmalignant 3T3 cells and their malignant SV40 transformants.
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Selected References
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- Aaronson S. A., Todaro G. J. Development of 3T3-like lines from Balb-c mouse embryo cultures: transformation susceptibility to SV40. J Cell Physiol. 1968 Oct;72(2):141–148. doi: 10.1002/jcp.1040720208. [DOI] [PubMed] [Google Scholar]
- Ben-Shaul Y., Moscona A. A. Scanning electron microscopy of aggregating embryonic neural retina cells. Exp Cell Res. 1975 Oct 1;95(1):191–204. doi: 10.1016/0014-4827(75)90624-2. [DOI] [PubMed] [Google Scholar]
- Collard J. G., Temmink J. H. Surface morphology and agglutinability with concanavalin A in normal and transformed murine fibroblasts. J Cell Biol. 1976 Jan;68(1):101–112. doi: 10.1083/jcb.68.1.101. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Follett E. A., Goldman R. D. The occurrence of microvilli during spreading and growth of BHK21-C13 fibroblasts. Exp Cell Res. 1970 Jan;59(1):124–136. doi: 10.1016/0014-4827(70)90631-2. [DOI] [PubMed] [Google Scholar]
- Gershman H., Drumm J. Mobility of normal and virus-transformed cells in cellular aggregates. J Cell Biol. 1975 Nov;67(2PT1):419–435. doi: 10.1083/jcb.67.2.419. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mazia D., Schatten G., Sale W. Adhesion of cells to surfaces coated with polylysine. Applications to electron microscopy. J Cell Biol. 1975 Jul;66(1):198–200. doi: 10.1083/jcb.66.1.198. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Porter K. R., Puck T. T., Hsie A. W., Kelley D. An electron microscopy study of the effects on dibutyryl cyclic AMP on Chinese hamster ovary cells. Cell. 1974 Jul;2(3):145–162. doi: 10.1016/0092-8674(74)90089-0. [DOI] [PubMed] [Google Scholar]
- Revel J. P., Wolken K. Electronmicroscope investigations of the underside of cells in culture. Exp Cell Res. 1973 Mar 30;78(1):1–14. doi: 10.1016/0014-4827(73)90031-1. [DOI] [PubMed] [Google Scholar]
- Rosen J. J., Culp L. A. Morphology and cellular origins of substrate-attached material from mouse fibroblasts. Exp Cell Res. 1977 Jun;107(1):139–149. doi: 10.1016/0014-4827(77)90395-0. [DOI] [PubMed] [Google Scholar]
- Turner F. R., Mahowald A. P. Scanning electron microscopy of Drosophila embryogenesis. 1. The structure of the egg envelopes and the formation of the cellular blastoderm. Dev Biol. 1976 May;50(1):95–108. doi: 10.1016/0012-1606(76)90070-1. [DOI] [PubMed] [Google Scholar]
- Vial J., Porter K. R. Scanning microscopy of dissociated tissue cells. J Cell Biol. 1975 Nov;67(2PT1):345–360. doi: 10.1083/jcb.67.2.345. [DOI] [PMC free article] [PubMed] [Google Scholar]