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Updated: Aug 8, 2026
Evaluation of Mammary Gland Development and Function in Mouse Models
Published on: July 21, 2011
Organic and inorganic selenium compounds inhibit mouse mammary cell growth in vitro by different cellular pathways
Abstract:
Selenium, both organic and inorganic forms, inhibit mammary tumorigenesis in vivo and mammary cell growth in vitro. In the present study, sodium selenite was compared to methylselenocysteine (MSC) for their individual effects on cell growth, cdc2/cdk2 kinase activities and the levels of cyclins D1, E and A bound to cdk2 in a mouse mammary epithelial cell culture model. Selenite arrested the growth of cells in S-G2-M phase in contrast to MSC which arrested or delayed the cells in G1. In MSC-treated cells there was a 57% drop in the cdk2 kinase activity accompanied by a 73.5% decrease in cyclin E-cdk2 content as compared to the control cells. Selenite treatment increased the cdk2 kinase activity by 30% without any appreciable change in either of the cyclins D1, E or A bound to cdk2 when compared to the control cells. These data support the hypothesis that selenite and MSC have distinct modes of action in the inhibition of cell growth in vitro. Selenite has a strong genotoxic effect on the tumor cells; in contrast, MSC appears to inhibit cell growth via specific inhibition of cell cycle regulatory proteins.
Insights
Selenium compounds, sodium selenite and methylselenocysteine (MSC), inhibit mammary cell growth through distinct mechanisms. Selenite causes genotoxicity, while MSC specifically targets cell cycle proteins, affecting cell division.
Area of Science:
- Biochemistry
- Cell Biology
- Oncology
Background:
- Selenium compounds, including organic and inorganic forms, are known to inhibit mammary tumorigenesis in vivo and mammary cell growth in vitro.
- Understanding the distinct mechanisms of action of different selenium compounds is crucial for their therapeutic application.
Purpose of the Study:
- To compare the effects of sodium selenite and methylselenocysteine (MSC) on mouse mammary epithelial cell growth.
- To investigate their individual impacts on cell cycle progression, cdc2/cdk2 kinase activities, and cyclin D1, E, and A levels bound to cdk2.
Main Methods:
- Mouse mammary epithelial cell culture model.
- Treatment with sodium selenite and methylselenocysteine (MSC).
- Analysis of cell growth, cell cycle phase distribution, cdc2/cdk2 kinase activities, and cyclin-cdk2 complex levels.
Main Results:
- Sodium selenite arrested cell growth in the S-G2-M phase, while MSC caused G1 arrest or delay.
- MSC treatment reduced cdk2 kinase activity by 57% and cyclin E-cdk2 content by 73.5%.
- Selenite treatment increased cdk2 kinase activity by 30% without significantly altering cyclin D1, E, or A levels bound to cdk2.
Conclusions:
- Sodium selenite and methylselenocysteine (MSC) exhibit distinct mechanisms in inhibiting mammary cell growth in vitro.
- Selenite demonstrates a genotoxic effect on tumor cells.
- MSC appears to inhibit cell growth through specific targeting of cell cycle regulatory proteins.
