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Proliferation of human mammary cancer cells exposed to 27-hydroxycholesterol
Pamela Cruz1, Cristian Torres, María Eugenia Ramírez
1Laboratorio de Nutrición y Regulación Metabólica, INTA-Universidad de Chile , Santiago 7830489;
Abstract:
The aim of the present study was to identify the possible mechanisms by which certain estradiol receptor (ER)-positive mammary tumor cells remain resistant to treatment with anti-estrogens or inhibitors of local estradiol (E(2)) production. To this end, we compared the proliferative effects on mammary cancer cells of the novel selective ER modulator 27-hydroxycholesterol (27OHC) to those of E(2), and evaluated their inhibition by ICI 182,780 (ICI). Analysis of the effects on the cell cycle of 27OHC and E(2) in the absence or presence of ICI was conducted. In ER-positive mammary tumor cells, we detected the blocking of 27OHC proliferation-stimulatory activity by simvastatin, as well as the inhibition of E(2)-stimulated proliferation by an α-fetoprotein-derived cyclic nonapeptide. The effects reported herein may be extrapolated to infiltrating mammary cancer, where the activity of local macrophages may stimulate tumor growth. We suggest that increased breast cancer growth in obese patients may be related to increased 27OHC circulatory levels.
Insights
Estradiol receptor-positive breast cancer cells show resistance to anti-estrogen therapies. Novel compounds like 27-hydroxycholesterol and specific peptides offer potential therapeutic strategies for overcoming this resistance.
Area of Science:
- Oncology
- Endocrinology
- Molecular Biology
Background:
- Estradiol receptor (ER)-positive mammary tumors often develop resistance to anti-estrogen therapies and local estradiol (E(2)) production inhibitors.
- Understanding the mechanisms of this resistance is crucial for developing effective breast cancer treatments.
Purpose of the Study:
- To investigate the mechanisms underlying resistance in ER-positive mammary tumor cells.
- To compare the proliferative effects of 27-hydroxycholesterol (27OHC), a novel selective ER modulator, with estradiol (E(2)) and assess their inhibition by ICI 182,780 (ICI).
Main Methods:
- Compared the proliferative effects of 27OHC and E(2) on mammary cancer cells.
- Evaluated the inhibition of these effects by ICI 182,780.
- Analyzed cell cycle effects of 27OHC and E(2) with and without ICI.
- Tested simvastatin for blocking 27OHC activity and an alpha-fetoprotein-derived cyclic nonapeptide for inhibiting E(2)-stimulated proliferation.
Main Results:
- Simvastatin blocked the proliferation-stimulatory activity of 27OHC in ER-positive mammary tumor cells.
- An alpha-fetoprotein-derived cyclic nonapeptide inhibited E(2)-stimulated proliferation.
- These findings suggest potential therapeutic avenues for overcoming resistance.
Conclusions:
- The study identifies potential mechanisms for overcoming resistance in ER-positive breast cancer.
- Findings may be relevant to infiltrating mammary cancer, considering the role of macrophages in tumor growth.
- Increased breast cancer growth in obese patients might be linked to elevated 27OHC levels.
