1. Women's Hospital, and Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
2. State Key Laboratory for Medical Genomics, National Research Center for Translational Medicine at Shanghai, Shanghai Institute of Hematology, Rui-Jin Hospital affiliated to Shanghai Jiao-Tong University School of Medicine, Shanghai, China.
3. Department of biophysics and Kidney Disease Center of the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
4. Women's Hospital, and Institute of Genetics, and Department of Environmental Medicine, Zhejiang University School of Medicine, Hangzhou, China.
5. College of Pharmaceutical Sciences, Zhejiang University.
6. Zhejiang University-University of Edinburgh united Institute.
7. Key Laboratory of Adult Stem Cell Translational Research, Chinese Academy of Medical Sciences, National & Guizhou Joint Engineering Laboratory for Cell Engineering and Biomedicine Technique, Guizhou Province Key Laboratory of Regenerative Medicine, Guizhou Medical University, Guiyang, Guizhou, China, 550004.
8. Harvard Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA.
9. Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital, Pediatric Hematology/Oncology at Dana Farber Cancer Institute, Harvard Stem Cell Institute, Harvard Medical School and Howard Hughes Medical Institute, Boston, MA 02115, USA.
#These authors contributed equally to this article and should be regarded as joint first authors.
Rationale: Tanshinone, a type of diterpenes derived from salvia miltiorrhiza, is a particularly promising herbal medicine compound for the treatment of cancers including acute myeloid leukemia (AML). However, the therapeutic function and the underlying mechanism of Tanshinone in AML are not clear, and the toxic effect of Tanshinone limits its clinical application.
Methods: Our work utilizes human leukemia cell lines, zebrafish transgenics and xenograft models to study the cellular and molecular mechanisms of how Tanshinone affects normal and abnormal hematopoiesis. WISH, Sudan Black and O-Dianisidine Staining were used to determine the expression of hematopoietic genes on zebrafish embryos. RNA-seq analysis showed that differential expression genes and enrichment gene signature with Tan I treatment. The surface plasmon resonance (SPR) method was used with a BIAcore T200 (GE Healthcare) to measure the binding affinities of Tan I. In vitro methyltransferase assay was performed to verify Tan I inhibits the histone enzymatic activity of the PRC2 complex. ChIP-qPCR assay was used to determine the H3K27me3 level of EZH2 target genes.
Results: We found that Tanshinone I (Tan I), one of the Tanshinones, can inhibit the proliferation of human leukemia cells in vitro and in the xenograft zebrafish model, as well as the normal and malignant definitive hematopoiesis in zebrafish. Mechanistic studies illustrate that Tan I regulates normal and malignant hematopoiesis through direct binding to EZH2, a well-known histone H3K27 methyltransferase, and inhibiting PRC2 enzymatic activity. Furthermore, we identified MMP9 and ABCG2 as two possible downstream genes of Tan I's effects on EZH2.
Conclusions: Together, this study confirmed that Tan I is a novel EZH2 inhibitor and suggested MMP9 and ABCG2 as two potential therapeutic targets for myeloid malignant diseases.
Keywords: Tanshinone I, hematopoiesis, leukemia, EZH2, H3K27me3