Department of Gynecology and Obstetrics, University Medical Center Regensburg, Regensburg, Germany.
Anticancer Drugs. 2013 Feb;24(2):150-7. doi: 10.1097/CAD.0b013e32835a7e29.
Previously, we have shown that the targeted cytotoxic somatostatin (sst) analogue AN-162 [AZSE-124] inhibits the growth of MDA-MB-231 human breast cancers xenografted into nude mice. In this study, we examined the trafficking of AN-162 into the cell, the expression of the somatostatin receptors (sstr) in specimens of human triple-negative breast cancers (TNBC), and the effect of AN-162 on HCC 1806 human TNBC xenografts. The expression of sstr in TNBC tumor samples was investigated by immunohistochemical staining. The expression of sstr in HCC 1806 was evaluated by reverse transcription PCR. Internalization studies with I-labeled AN-162 were carried out and the autofluorescence sign of doxorubicin moiety in the cell nucleus after incubation with AN-162 was measured using a fluorescence assay. The effects of AN-162 on the growth of HCC 1806 xenografted into nude mice were studied. A fluorescence microscopy cytotoxicity assay in vitro to detect cell death after treatment with AN-162 was also carried out. About 28% of TNBC tumor specimens showed a positive staining for sstr subtype 2a. HCC 1806 expresses all five subtypes of sstr. In the fluorescence cytotoxicity assay, dead HCC 1806 cells were found 24 h after incubation with AN-162. The growth of HCC 1806 tumors in nude mice was significantly inhibited by treatment with AN-162. AN-162 was internalized into the HCC 1806 cells and doxorubicin moiety was detected in the cell nuclei. This study is the first to show that the trafficking of the cytotoxic sst analogue AN-162 into the cell is mediated by sstr. Our work shows that the growth of xenografted HCC 1806 TNBCs can be effectively inhibited in vivo with AN-162. This investigation provides information on the mechanism of action and efficacy of this new targeted cytotoxic sst analogue and identifies in this relation the sstr as a favorable therapeutic target in TNBC.
先前，我们已经表明，靶向细胞毒性生长抑素（sst）类似物 AN-162[AZSE-124]可抑制异种移植到裸鼠体内的 MDA-MB-231 人乳腺癌的生长。在这项研究中，我们研究了 AN-162 进入细胞的运输、人三阴性乳腺癌（TNBC）标本中生长抑素受体（sstr）的表达，以及 AN-162 对 HCC 1806 人 TNBC 异种移植瘤的影响。通过免疫组织化学染色研究了 sstr 在 TNBC 肿瘤样本中的表达。通过逆转录 PCR 评估了 HCC 1806 中 sstr 的表达。用 I 标记的 AN-162 进行内化研究，并使用荧光测定法测量孵育后 AN-162 中阿霉素部分在细胞核中的自发荧光信号。研究了 AN-162 对裸鼠异种移植 HCC 1806 生长的影响。还进行了体外荧光显微镜细胞毒性测定，以检测用 AN-162 处理后细胞死亡的情况。约 28%的 TNBC 肿瘤标本对 sstr 亚型 2a 呈阳性染色。HCC 1806 表达所有五种亚型的 sstr。在荧光细胞毒性测定中，孵育 24 小时后发现 HCC 1806 细胞死亡。用 AN-162 处理可显著抑制裸鼠 HCC 1806 肿瘤的生长。AN-162 被内化到 HCC 1806 细胞中，并在细胞核中检测到阿霉素部分。这项研究首次表明，细胞毒性 sst 类似物 AN-162 进入细胞的运输是由 sstr 介导的。我们的工作表明，用 AN-162 体内可有效抑制异种移植 HCC 1806 TNBC 的生长。这项研究提供了关于这种新型靶向细胞毒性 sst 类似物的作用机制和疗效的信息，并确定了 sstr 作为 TNBC 有利的治疗靶点。
