Recent clinical trials with histone deacetylase inhibitors (HDACi) have shown increased progression free survival by re-sensitizing resistant estrogen receptor positive (ER+) breast cancer cells to hormone suppressive...Recent clinical trials with histone deacetylase inhibitors (HDACi) have shown increased progression free survival by re-sensitizing resistant estrogen receptor positive (ER+) breast cancer cells to hormone suppressive therapies (HT). However, these trials lacked a sensitive, specific assay to identify and monitor HDACi/HT sensitive or resistant tumors. We tested detection of ER expression and histone acetylation of chromatin at the growth regulation by estrogen in breast cancer 1 (GREB1) gene, an estrogen-responsive gene involved in ER expression, in circulating tumor cell (CTC) as potential candidate assays for HDACi/HT sensitivity. ER+ and ER- CTC were detected and isolated from breast cancer patient peripheral blood by high speed fluorescence activated cell sorting (FACS) for use in mRNA analysis and anti-acetylated histone-mediated Chromatin Immunoprecipitation (ChIP). cDNA from mRNA and DNA extracted from the ChIP isolates were quantified by real-time PCR for GREB1. CTC isolates from patients who had an ER+ breast cancer primary contained both ER+ and ER- cells. More ER+ than ER- CTC was found in HT sensitive patients compared to HT resistant patients (p = 0.0559). GREB1 was found in acetylated histone chromatin from both ER+ and ER- CTC. The number of ER+ and ER- CTC found in peripheral blood appears to parallel patient outcomes as to their sensitivity to HT. Acetylated histone analysis can detect chromatin containing GREB1 in CTC, suggesting it may be useful as a more specific measure of HDACi effects on breast tumor cells. A larger, longitudinal data set following patients through HT/HDACi trials is needed to confirm these observations and their development for clinical use.展开更多
Promestriene (3-propyl ethyl, 17B-methyl estradiol) is a synthetic estrogen analogue with reported minimal systemic absorption which has been suggested for topical treatment of vaginal atrophy. Promestriene’s ability...Promestriene (3-propyl ethyl, 17B-methyl estradiol) is a synthetic estrogen analogue with reported minimal systemic absorption which has been suggested for topical treatment of vaginal atrophy. Promestriene’s ability to stimulate proliferation and estrogen responsive gene expression was analyzed in estrogen receptor (ER+) positive breast cancer cell lines MCF-7, T-47D, and BT-474 using CFSE flow cytometric analysis, and quantitative RT-PCR analysis of GREB1 RNA expression, an estrogen responsive gene involved in estrogen receptor alpha expression. In estrogen replete conditions, Promestriene did not stimulate proliferation even at high concentrations (100,000 pg/ml). However, anti-estradiol depletion allowed low dose Promestriene (2 - 10 pg/ml) to stimulate GREB1 expression in all three cell lines at levels equal to that induced by estradiol (BT-474) or significantly higher than estradiol (MCF7 and T-47D). These findings suggest that Promestriene has the potential to support estrogen like cell signaling, a possible contraindication for use in treatment of vaginal atrophy associated with breast cancer aromatase inhibitor therapy.展开更多
文摘Recent clinical trials with histone deacetylase inhibitors (HDACi) have shown increased progression free survival by re-sensitizing resistant estrogen receptor positive (ER+) breast cancer cells to hormone suppressive therapies (HT). However, these trials lacked a sensitive, specific assay to identify and monitor HDACi/HT sensitive or resistant tumors. We tested detection of ER expression and histone acetylation of chromatin at the growth regulation by estrogen in breast cancer 1 (GREB1) gene, an estrogen-responsive gene involved in ER expression, in circulating tumor cell (CTC) as potential candidate assays for HDACi/HT sensitivity. ER+ and ER- CTC were detected and isolated from breast cancer patient peripheral blood by high speed fluorescence activated cell sorting (FACS) for use in mRNA analysis and anti-acetylated histone-mediated Chromatin Immunoprecipitation (ChIP). cDNA from mRNA and DNA extracted from the ChIP isolates were quantified by real-time PCR for GREB1. CTC isolates from patients who had an ER+ breast cancer primary contained both ER+ and ER- cells. More ER+ than ER- CTC was found in HT sensitive patients compared to HT resistant patients (p = 0.0559). GREB1 was found in acetylated histone chromatin from both ER+ and ER- CTC. The number of ER+ and ER- CTC found in peripheral blood appears to parallel patient outcomes as to their sensitivity to HT. Acetylated histone analysis can detect chromatin containing GREB1 in CTC, suggesting it may be useful as a more specific measure of HDACi effects on breast tumor cells. A larger, longitudinal data set following patients through HT/HDACi trials is needed to confirm these observations and their development for clinical use.
文摘Promestriene (3-propyl ethyl, 17B-methyl estradiol) is a synthetic estrogen analogue with reported minimal systemic absorption which has been suggested for topical treatment of vaginal atrophy. Promestriene’s ability to stimulate proliferation and estrogen responsive gene expression was analyzed in estrogen receptor (ER+) positive breast cancer cell lines MCF-7, T-47D, and BT-474 using CFSE flow cytometric analysis, and quantitative RT-PCR analysis of GREB1 RNA expression, an estrogen responsive gene involved in estrogen receptor alpha expression. In estrogen replete conditions, Promestriene did not stimulate proliferation even at high concentrations (100,000 pg/ml). However, anti-estradiol depletion allowed low dose Promestriene (2 - 10 pg/ml) to stimulate GREB1 expression in all three cell lines at levels equal to that induced by estradiol (BT-474) or significantly higher than estradiol (MCF7 and T-47D). These findings suggest that Promestriene has the potential to support estrogen like cell signaling, a possible contraindication for use in treatment of vaginal atrophy associated with breast cancer aromatase inhibitor therapy.
