细胞周期蛋白D1过表达与乳腺癌模型中硼替佐米治疗反应

Cyclin D1 overexpression and response to bortezomib treatment in a breast cancer model.

作者信息

Ishii Yuki, Pirkmaier Andreja, Alvarez James V, Frank David A, Keselman Inna, Logothetis Diomedes, Mandeli John, O'Connell Matthew J, Waxman Samuel, Germain Doris

机构信息

Division of Hematology/Oncology, Department of Medicine, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA.

出版信息

J Natl Cancer Inst. 2006 Sep 6;98(17):1238-47. doi: 10.1093/jnci/djj334.

DOI:10.1093/jnci/djj334

PMID:16954476

Abstract

BACKGROUND

Cyclin D1 is frequently overexpressed in breast cancer, and its overexpression is, surprisingly, associated with improved survival. One potential mechanism for this association involves signal transducer and activator of transcription 3 (STAT3).

METHODS

Cyclin D1 and STAT3 expression were assessed in human tumors using microarray analysis and in breast cancer cell lines HBL100, T47D, MCF7, MDA-MB-453, and BT20 and in HBL100 and T47D cells stably overexpressing cyclin D1 using immunoblot analysis. Cyclin D1 protein was stabilized by treatment with the proteasome inhibitor bortezomib, and the effects on STAT3 expression in vitro was determined by using immunoblotting and on xenograft tumor growth and apoptosis in vivo was determined by using terminal deoxyuridine nick-end labeling assays. All statistical tests were two-sided.

RESULTS

Tumors with high cyclin D1 expression (n = 17) had low STAT3 expression (mean = 274 arbitrary units), and those with low cyclin D1 expression (n = 31) had high STAT3 expression (mean = 882 arbitrary units) (P<.001). In HBL100 and T47D parental and cyclin D1-overexpressing cells, cyclin D1 overexpression was also inversely associated with STAT3 expression, and cyclin D1 directly reduced the expression of STAT3. Stabilization of cyclin D1 protein by bortezomib treatment further amplified the cyclin D1-dependent repression of STAT3 in vitro and slowed tumor growth in vivo (week 7: untreated mean = 185.7 mm3 versus treated mean = 136.2 mm3, difference = 49.5 mm3, 95% confidence interval [CI] = 18 to 81 mm3, P = .007; week 8: untreated mean = 240.2 mm3 versus treated mean = 157.3 mm3, difference = 82.9 mm3, 95% CI = 9.1 to 156.7 mm3, P = .0014; and week 9: untreated mean = 256.4 mm3 versus treated mean = 170.2 mm3, difference = 86.2 mm3, 95% CI = 22.8 to 149.6 mm3, P = .006) and increased apoptosis (untreated mean = 19% versus treated mean = 54%, difference = 35%, 95% CI = 24.7% to 45.4%; P = .013) of xenograft tumors.

CONCLUSIONS

Cyclin D1 repression of STAT3 expression may explain the association between cyclin D1 overexpression and improved outcome in breast cancer. In addition, bortezomib can amplify the proapoptotic function of cyclin D1, raising the possibility that cyclin D1 levels may be a marker for predicting the response to this novel drug.

摘要

背景

细胞周期蛋白D1（Cyclin D1）在乳腺癌中常过度表达，令人惊讶的是，其过度表达与生存率提高相关。这种关联的一种潜在机制涉及信号转导和转录激活因子3（STAT3）。

方法

使用微阵列分析评估人类肿瘤中Cyclin D1和STAT3的表达，并使用免疫印迹分析评估乳腺癌细胞系HBL100、T47D、MCF7、MDA-MB-453和BT20以及稳定过度表达Cyclin D1的HBL100和T47D细胞中的表达。用蛋白酶体抑制剂硼替佐米处理使Cyclin D1蛋白稳定，通过免疫印迹法测定其对体外STAT3表达的影响，通过末端脱氧尿苷缺口末端标记试验测定其对体内异种移植肿瘤生长和凋亡的影响。所有统计检验均为双侧检验。

结果

Cyclin D1高表达的肿瘤（n = 17）STAT3表达低（平均值 = 274任意单位），而Cyclin D1低表达的肿瘤（n = 31）STAT3表达高（平均值 = 882任意单位）（P <.001）。在HBL100和T47D亲本细胞以及Cyclin D1过度表达的细胞中，Cyclin D1过度表达也与STAT3表达呈负相关，且Cyclin D1直接降低STAT3的表达。硼替佐米处理使Cyclin D1蛋白稳定，进一步增强了体外Cyclin D1对STAT3的依赖性抑制作用，并减缓了体内肿瘤生长（第7周：未处理平均值 = 185.7 mm3，处理后平均值 = 136.2 mm3，差异 = 49.5 mm3，95%置信区间[CI] = 18至81 mm3，P =.007；第8周：未处理平均值 = 240.2 mm3，处理后平均值 = 157.3 mm3，差异 = 82.9 mm3，95% CI = 9.1至156.7 mm3，P =.0014；第9周：未处理平均值 = 256.4 mm3，处理后平均值 = 170.2 mm3，差异 = 86.2 mm3，95% CI = 22.8至149.6 mm3，P =.006），并增加了异种移植肿瘤的凋亡（未处理平均值 = 19%，处理后平均值 = 54%，差异 = 35%，95% CI = 24.7%至45.4%；P =.013）。