Malignant transformation of human cell in vitro by the SV 40 DNA and related alteration in biological activity of cell membranes.


In vitro cell transformation of human embryonic cells could be induced by DNA extracted from virions of SV 40 purified by density gradient centrifugation. The result shows clearly that cell transformation is in· duced by incorporation ofa part of viral DNA into the genome. In addition, for the purpose of clarifing the biological differences between the normal and transformant, the alteration of the cell membrane structures of transformants was observed from the mechanism of phagocytosis. The iron colloid particles are taken up by normal diploid fibroblasts but not by the human and hamster transformants. This fact suggests a difference in the molecular arrangement of the cell membranes between the normal and transformants. In the presence of histones, however, the transformants phagocytize the colloid particles very actively. The results show cell membranes of transformants are altered in the molecular structure responsible for the surface charge. ∗PMID: 4333632 [PubMed indexed for MEDLINE] Copyright c ©OKAYAMA UNIVERSITY MEDICAL SCHOOL Acta Med. Okayama 25, 77-86 (971) MALIGNANT TRANSFORMATION OF HUMAN CELL IN VITRO BY THE SV 40 DNA AND RELATED ALTERATION IN BIOLOGICAL ACTIVITY OF CELL MEMBRANES Tetsuo KIMOTO, E-iti YOKOMURA, Yoriko SHIMIZU, Morihei YAMAKAW A and Satimaru SENO Department of Pathology, Okayama University Medical School Okayama, Japan (Director: Prof. S. Seno) Received for publication, February 10, 1971 As reported first by ABERCROMBIE (1), the cell division of normal and non-neoplastic cell lines (fibroblasts) in culture is largely suppressed by contact with neighboring cells, i. e. contact inhibition. By the malignant transformation, however, the cells (transformants) lose much of their inhibitory effect on the neighboring cells piling up one another, eventually forming a gross lump of the transformed cells. This means the loss of normal characteristics of the cell behavior and such a change in the cell characteristics serves as the very marker for the malignant transformation of the cells, though occasionally normal cells also become slightly insensitive to the "cell contact". The outer coat of the cell membrane composed of glycolipid should be directly related to the phenomenon and the alteration in its architectural structure or molecular arrangement with some qualitative and quantative changes may be responsible for the insensitivity to contact inhibition because the changes in electric charge of the cell surface are clearly observable in relation to the malignant transformation or to the loss of contact inhibition. The changes in cell surface seem also to suggest the appearance of the specific surface antigen that is found on the cell surfaces of the transformants induced by oncogenic virus (polyoma, adeno virus 12 and SV 40). Besides these, YOKOMURA and others (2, .3) revealed that the phagocytic activity of the cell is closely correlated to the specificity of the cell membrane indicating that such substances absorbed on the cell surface are solely taken by the celL This indicates that the phagocytic activity of the cell is closely connected to the specific molecular structure of the cell surface. In this paper, dealing with human and hamster embryonic cells and their transformant induced by SV40 and its extracted DNA, it is reported that the phagocytic activity gives a good and sensitive information for the

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@article{Kimoto1971MalignantTO, title={Malignant transformation of human cell in vitro by the SV 40 DNA and related alteration in biological activity of cell membranes.}, author={Takafumi Kimoto and E-iti Yokomura and Yuji Shimizu and Masaaki Yamakawa and Satsuki Seno}, journal={Acta medicinae Okayama}, year={1971}, volume={25 2}, pages={77-86} }