Detection of Estrogen Responsive Breast Cancer Circulating Tumor Cells: Assay Development for Anti-Hormone Therapy Resistance

• 作者: Alvin J. O. Almodovar David A. Decker Elizabeth Griffith Louis Barr Na’im Fanaian Robert Reynolds Ryan Sause Sally A. Litherland Stephanie Dickstein Tiffany Encarnacion Xiang Zhu Yai-Ping Shao
• 来源期刊: 癌症治疗(英文)
• 学科: 医学
• 关键词: EPIGENETICS Breast Cancer ESTROGEN Receptor Histone ACETYLATION Anti-Hormone Therapy
• 年，卷（期）: azzlyw_2015,（9）
• 页码范围: 773-782
• 页数: 10页
• 分类号: R73

摘要

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.