Some Effects of Hypervitaminosis A on Metastasis of Spontaneous Breast Cancer in Mice

The effects of hypervitaminosis A on the pulmonary metastatic pattern of spontaneous mammary tumors in mice were studied in three groups with spontaneous mammary tumors: an overall control group (I), a hypervitaminotic group (III) and a group (II), in which the mean body weight was kept at that of g...

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Bibliographic Details
Published in:JNCI : Journal of the National Cancer Institute 1969-11, Vol.43 (5), p.1045-1054
Main Authors: Weiss, L., Holyoke, E. D.
Format: Article
Language:English
Subjects:
Animals
Breast Neoplasms
Diet
Enzyme Activation
Lung Neoplasms
Lysosomes
Mice
Neoplasm Metastasis - chemically induced
Neoplasm Transplantation
Vitamin A - adverse effects
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Summary:The effects of hypervitaminosis A on the pulmonary metastatic pattern of spontaneous mammary tumors in mice were studied in three groups with spontaneous mammary tumors: an overall control group (I), a hypervitaminotic group (III) and a group (II), in which the mean body weight was kept at that of group III by diet restriction. A greater percentage of animals developed metastases in group III, and in these, more pulmonary metastases per animal occurred. In in vitro experiments, cells were liberated more easily from tumors of group III than in the other groups; cell detachment was made easier by lysosomal enzymes, and hypervitaminosis A neither demonstrably affected the retention of tumor cells in the lungs nor their growth in this organ. It is suggested that hypervitaminosis A promotes pulmonary metastasis through facilitated release of cells from primary tumors, which is mediated through released lysosomal enzymes. Other mechanisms of lysosomal activation, which may be immunological or due to chemotherapy, may also increase metastases.
ISSN:0027-8874
1460-2105
1460-2105
DOI:10.1093/jnci/43.5.1045