17-烯丙氨基-17-去甲氧基格尔德霉素治疗导致磁共振波谱检测到胆碱代谢物升高，与胆碱转运蛋白 SLC44A1 和磷脂酶 A2 的表达增加有关。
17-allyamino-17-demethoxygeldanamycin treatment results in a magnetic resonance spectroscopy-detectable elevation in choline-containing metabolites associated with increased expression of choline transporter SLC44A1 and phospholipase A2.
机构信息
Department of Radiology and Biomedical Imaging, University of California, San Francisco, 94158, USA.
出版信息
Breast Cancer Res. 2010;12(5):R84. doi: 10.1186/bcr2729. Epub 2010 Oct 14.
INTRODUCTION
17-allyamino-17-demethoxygeldanamycin (17-AAG), a small molecule inhibitor of Hsp90, is currently in clinical trials in breast cancer. However, 17-AAG treatment often results in inhibition of tumor growth rather than shrinkage, making detection of response a challenge. Magnetic resonance spectroscopy (MRS) and spectroscopic imaging (MRSI) are noninvasive imaging methods than can be used to monitor metabolic biomarkers of drug-target modulation. This study set out to examine the MRS-detectable metabolic consequences of Hsp90 inhibition in a breast cancer model.
METHODS
MCF-7 breast cancer cells were investigated, and MRS studies were performed both on live cells and on cell extracts. (31)P and (1)H MRS were used to determine total cellular metabolite concentrations and (13)C MRS was used to probe the metabolism of [1,2-(13)C]-choline. To explain the MRS metabolic findings, microarray and RT-PCR were used to analyze gene expression, and in vitro activity assays were performed to determine changes in enzymatic activity following 17-AAG treatment.
RESULTS
Treatment of MCF-7 cells with 17-AAG for 48 hours caused a significant increase in intracellular levels of choline (to 266 ± 18% of control, P = 0.05) and phosphocholine (PC; to 181 ± 10% of control, P = 0.001) associated with an increase in expression of choline transporter SLC44A1 and an elevation in the de novo synthesis of PC. We also detected an increase in intracellular levels of glycerophosphocholine (GPC; to 176 ± 38% of control, P = 0.03) associated with an increase in PLA2 expression and activity.
CONCLUSIONS
This study determined that in the MCF-7 breast cancer model inhibition of Hsp90 by 17-AAG results in a significant MRS-detectable increase in choline, PC and GPC, which is likely due to an increase in choline transport into the cell and phospholipase activation. (1)H MRSI can be used in the clinical setting to detect levels of total choline-containing metabolite (t-Cho, composed of intracellular choline, PC and GPC). As Hsp90 inhibitors enter routine clinical use, t-Cho could thus provide an easily detectable, noninvasive metabolic biomarker of Hsp90 inhibition in breast cancer patients.
简介
17- 烯丙氨基-17- 去甲氧基格尔德霉素（17-AAG）是一种小分子热休克蛋白 90（Hsp90）抑制剂，目前正在乳腺癌的临床试验中进行研究。然而，17-AAG 治疗通常导致肿瘤生长的抑制而不是缩小，这使得检测反应成为一个挑战。磁共振波谱（MRS）和波谱成像（MRSI）是两种非侵入性的成像方法，可用于监测药物靶标调节的代谢生物标志物。本研究旨在探讨乳腺癌模型中 Hsp90 抑制的 MRS 可检测的代谢后果。
方法
研究了 MCF-7 乳腺癌细胞，并且在活细胞和细胞提取物上进行了 MRS 研究。（31）P 和（1）H MRS 用于确定总细胞代谢物浓度，（13）C MRS 用于探测[1,2-（13）C]-胆碱的代谢。为了解释 MRS 代谢发现，使用微阵列和 RT-PCR 分析基因表达，并进行体外活性测定以确定 17-AAG 处理后酶活性的变化。
结果
用 17-AAG 处理 MCF-7 细胞 48 小时导致细胞内胆碱水平显著增加（增加到对照的 266±18%，P=0.05）和磷酸胆碱（PC）增加（增加到对照的 181±10%，P=0.001），与胆碱转运蛋白 SLC44A1 的表达增加和 PC 的从头合成升高有关。我们还检测到细胞内甘油磷酸胆碱（GPC）水平升高（增加到对照的 176±38%，P=0.03），与 PLA2 表达和活性增加有关。
结论
本研究确定，在 MCF-7 乳腺癌模型中，Hsp90 的 17-AAG 抑制导致 MRS 可检测的胆碱、PC 和 GPC 显著增加，这可能是由于细胞内胆碱的摄取增加和磷脂酶的激活所致。（1）H MRSI 可用于临床环境中检测总胆碱含量代谢物（t-Cho，由细胞内胆碱、PC 和 GPC 组成）的水平。随着 Hsp90 抑制剂常规临床应用，t-Cho 可能成为乳腺癌患者 Hsp90 抑制的一种易于检测、非侵入性代谢生物标志物。
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