Department of Clinical Laboratory, The Second Hospital, Cheeloo College of Medicine, Shandong University, 247 Beiyuan Street, Jinan, Shandong, 250033, China.
International Biotechnology R&D Center, Shandong University School of Ocean, 180 Wenhua Xi Road, Weihai, Shandong 264209, China.
Theranostics. 2020 Jul 25;10(21):9458-9476. doi: 10.7150/thno.44688. eCollection 2020.
It has been proposed that cancer stem/progenitor cells (or tumor-initiating cells, TICs) account for breast cancer initiation and progression. Sirtuins are nicotinamide adenine dinucleotide (NAD+)-dependent class-III histone deacetylases and mediate various basic biological processes, including metabolic homeostasis. However, interplay and cross-regulation among the sirtuin family are not fully understood. As one of the least studied sirtuin family members, the mitochondrial sirtuin SIRT4 is a tumor suppressor gene in various cancers. However, its role in cancer stemness, as well as initiation and progression of breast cancer, remains unknown. The expression of SIRT4 in breast cancer was analyzed using the TCGA breast cancer database and 3 GSEA data. Normal breast epithelial cells MCF10A and breast cancer cell lines MCF-7, MDA-MB-231, BT549, MDA-MB-468 were used to establish SIRT4 gene knockdown and corresponding overexpression cells. Identified MTT cytotoxicity assays, cell invasion and motility assay, sorting of SP, confocal immunofluorescence microscopy, mouse mammary stem cell analysis, glutamine and glucose production, clonogenic and sphere-formation assay, mass spectrometric metabolomics analysis and ChIP-seq to further explore SIRT4 biological role in breast cancer. We elucidated a novel role for SIRT4 in the negative regulation of mammary gland development and stemness, which is related to the mammary tumorigenesis. We also uncovered an inverse correlation between SIRT4 and SIRT1. Most importantly, SIRT4 negatively regulates SIRT1 expression via repressing glutamine metabolism. Besides, we identified H4K16ac and BRCA1 as new prime targets of SIRT4 in breast cancer. These results demonstrate that SIRT4 exerts its tumor-suppressive activity via modulating SIRT1 expression in breast cancer and provide a novel cross-talk between mitochondrial and nuclear sirtuins.
已经有人提出，癌症干细胞/祖细胞（或肿瘤起始细胞，TICs）是乳腺癌发生和发展的原因。沉默信息调节因子 2 相关酶 4（Sirtuins）是烟酰胺腺嘌呤二核苷酸（NAD+）依赖性 III 类组蛋白去乙酰化酶，介导各种基本的生物学过程，包括代谢稳态。然而，sirtuin 家族成员之间的相互作用和交叉调节尚未完全了解。作为研究最少的 sirtuin 家族成员之一，线粒体 sirtuin SIRT4 是各种癌症中的肿瘤抑制基因。然而，它在癌症干细胞特性以及乳腺癌的发生和发展中的作用尚不清楚。 使用 TCGA 乳腺癌数据库和 3 个 GSEA 数据分析 SIRT4 在乳腺癌中的表达。使用正常乳腺上皮细胞 MCF10A 和乳腺癌细胞系 MCF-7、MDA-MB-231、BT549、MDA-MB-468 建立 SIRT4 基因敲低和相应过表达细胞。通过 MTT 细胞毒性测定、细胞侵袭和迁移测定、SP 分选、共聚焦免疫荧光显微镜、小鼠乳腺干细胞分析、谷氨酰胺和葡萄糖产生、集落形成和球体形成测定、质谱代谢组学分析和 ChIP-seq 进一步探索 SIRT4 在乳腺癌中的生物学作用。 我们阐明了 SIRT4 在乳腺发育和干细胞特性的负调控中的新作用，这与乳腺肿瘤发生有关。我们还发现了 SIRT4 和 SIRT1 之间的负相关关系。最重要的是，SIRT4 通过抑制谷氨酰胺代谢来负调控 SIRT1 的表达。此外，我们还确定了 H4K16ac 和 BRCA1 是 SIRT4 在乳腺癌中的新的主要靶标。 这些结果表明，SIRT4 通过调节乳腺癌中的 SIRT1 表达发挥其肿瘤抑制活性，并为线粒体和核 sirtuins 之间提供了一种新的串扰。
