We are studying the effect of interleukin-1 IL-1) on MCF-7 human breast cancer cell growth and metabolism. We found that IL-1 inhibits in a dose-dependent manner the growth of these cells. IL-1 acts to block cell growth in the G(0)G(1) phase of the cell cycle. We also found the IL-1 blocks estradiol stimulated growth of these cells. This is dose-dependent for IL-1 and occurs for all concentrations of estradiol from 10-8 to 10-11M. IL-1 acts synergistically with the estrogen antagonist hydroxytamoxifen to further inhibit cell growth; this synergism with hydroxytamoxifen is also dose-dependent for IL01. IL-1 has been found to down-regulate the estrogen receptor (ER) in these cells by 38.0-44.0%. Down-regulation is demonstrated by both Scatchard analysis and enzyme immunoassay. Down-regulation occurs by 12 hours and persists through 48 hours of exposure, is dose-dependent, and occurs without a change in the receptor affinity constant (Kd) Down-regulation is blocked by cycloheximide, and thus requires continuous protein synthesis. IL-1 does not, however, alter expression of ER MRNA and therefore IL-1 is acting at the post-transcriptional level to down-regulate the ER. IL-1 did not block estradiol stimulation of progesterone (PgR) synthesis as determined by Scatchard analysis of EIA, and did not alter resting PgR levels. IL-1 also did not block estradiol down-regulation of the ER or ER MRNA. The effect of IL-1 on secretion of insulin-like growth factor was examined. IL-1 decreased resting levels of IGF, however, did not block estradiol stimulation of IGF secretion, further indicating that IL-1 selectively alters the estrogen responsiveness of these cells. We are currently studying the effect of IL-1 on growth and metabolism of MCF-7 cells in vivo in nude mice, as well as the effect of IL-1 on TGF-beta growth factor secretion, protooncogene erbB expression and EGF receptor expression, and modultion of estradiol regulation of cell cycle phase distribution.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Intramural Research (Z01)
Project #
1Z01CM006658-08
Application #
3874448
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
8
Fiscal Year
1990
Total Cost
Indirect Cost
Name
Division of Cancer Treatment
Department
Type
DUNS #
City
State
Country
United States
Zip Code