Discovery of a New STAT3 Inhibitor Acting on the Linker Domain
Discovery of a New STAT3 Inhibitor Acting on the Linker Domain
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DOI：
10.1248/bpb.b18-00992
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发表时间：
2019-05-01
影响因子：
2
通讯作者：
Asai, Akira
中科院分区：
文献类型：
--
作者：
Koseki, Tatsuya;Suehiro, Naoya;Asai, Akira
信号转导子和转录激活子3（STAT 3）是一种潜在的转录因子，其有助于肿瘤细胞的生长和存活，并且通常在几种类型的癌症中具有组成性活性，这使得其成为癌症治疗的有吸引力的靶标。我们鉴定了5，5 '-（戊-1，5'-二基）双（2-甲基-1，4-苯醌）（BPMB）作为新的STAT 3抑制剂。BPMB抑制STAT 3的转录活性，尽管它不能减少STAT 3的磷酸化和核转位。BPMB选择性地抑制具有组成性激活的STAT 3的人乳腺癌细胞系的增殖。此外，凝胶阻滞模式，获得免疫印迹只有当这些STAT 3激活的细胞系用BPMB处理。用抗STAT 3抗体可以免疫印迹出移动的条带，但用抗STAT 1/STAT 5抗体则不能，并且在还原条件下是稳定的。纯化的重组STAT 3蛋白用BPMB处理后得到类似的条带移动模式。基质辅助激光解吸/电离-质谱分析的组成部分，包括主要的移动频带表明，该复合物是一个STAT 3的同源二聚体交联的BPMB通过迈克尔除了与Cys 550在连接器域。在凝胶阻滞测定中，在该位置处的丙氨酸替换导致STAT 3二聚体形成的减少。因此，我们的研究结果表明，BPMB抑制STAT 3激活的细胞系的增殖，大概是通过酰化的连接结构域和随后的非活性STAT 3复合物的诱导。
Signal transducer and activator of transcription 3 (STAT3) is a latent transcription factor that contributes to tumor cell growth and survival and is often constitutively active in several types of cancers, which makes it an attractive target for cancer therapy. We identified 5,5'-(pentane-1,5'-diyl)bis(2-methyl-1,4-benzoquinone) (BPMB) as a new STAT3 inhibitor. BPMB inhibited the transcriptional activities of STAT3, despite its inability to reduce the phosphorylation and nuclear translocation of STAT3. BPMB selectively inhibited the proliferation of human breast cancer cell lines with constitutively activated STAT3. Furthermore, a gel retardation pattern was obtained by immunoblotting only when those STAT3-activated cell lines were treated with BPMB. The shifted bands could be immunoblotted with anti-STAT3 antibody but not with anti-STAT1/STAT5 antibody, and were stable under reducing conditions. The purified recombinant STAT3 protein treated with BPMB afforded a similar band shift pattern. Matrix-assisted laser desorption/ ionization-mass spectrometry analysis of the component comprising the main shifted band suggested that the complex is a STAT3 homodimer crosslinked by BPMB through a Michael addition with Cys550 in the linker domain. Alanine replacement at this position resulted in reduction of the STAT3 dimer formation in the gel retardation assay. Thus, our results suggest that BPMB inhibits the proliferation of STAT3-activated cell lines, presumably through acylation of the linker domain and subsequent induction of the inactive STAT3 complexes.