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Letters to the Editor
ber at 1 mM after treatments at 30 hpf (DMSO Uninject vs. CHMFL-FLT3-362 Uninject) (Figure 2D), indicating no apparent myelosuppression toxicity. In FLT3-ITD- transduced embryos, compound 362 effectively rescued the abnormal proliferation of mpx+ myeloid cells caused by overexpression of the FLT3-ITD gene (DMSO Inject vs. CHFML-FLT3-362 Inject) (Figure 2D) and inhibited the spread of FLT3-ITD-injected leukemic blasts at 1 mM (Online Supplementary Figure S6) indicating that com- pound 362 exerted its effects through FLT3-ITD on-tar- get inhibition. In addition, oral administration of 300, 600, and 1,200 mg/kg/day dosages for 14 days did not result in significant toxicity and weight loss in the mice (Online Supplementary Figure S7). Furthermore, bone marrow (BM) smear analysis also showed that com- pound 362 had no effect on the proliferation and activ- ity of mouse BM cells (Figure 2E).
To examine the inhibitory effects of compound 362 on tumor growth, different dosages of compound 362 were administered orally every day for 28 days in the subcutaneous MV4-11 cells xenograft mice model. It displayed dose-dependent anti-tumor efficacy and achieved the tumor growth inhibition of 95% at a dosage of 150 mg/kg/day (Figure 2F). No weight loss or any other obvious signs of toxicity was observed. Immunohistochemistrystaining of the tumor tissue also confirmed that the cell proliferation was inhibited (Ki- 67 staining) and the apoptosis was induced (TUNEL staining) (Online Supplementary Figure S8A-C). We then further confirmed the anti-tumor efficacy of compound 362 in an orthotopic model of BM engraftment using MV4-11 and MOLM-13 cells, which physiologically dif- fers from the subcutaneous MV4-11 xenograft model. Compound 362 dose-dependently extended the survival of mice at 50, 100, and 150 mg/kg/day dosages with no apparent weight loss at all dosages (Figure 2G and Online Supplementary Figure S8D and E). Flow cytometry analysis revealed significant reduction of the MV4-11 cells in the BM in this in vivo model (Online Supplementary Figure S9).
In this study, we describe a novel FLT3-ITD mutant selective inhibitor CHMFL-FLT3-362, which achieved 30-fold selectivity between FLT3-ITD mutants and FLT3-wt in biochemical assays and 10-fold selectivity in cellular context. Considering that FLT3-wt is essential for the proliferation of normal primitive hematopoietic cells, this selectivity indicates that it might provide bet- ter safety profiles. In addition, compound 362 was potent against different ITD mutants which are more relevant to the clinically observed heterogenicity. Furthermore, it also achieved great selectivity over cKIT kinase which would help to avoid the myeloid suppres- sion toxicity due to the FLT3/cKIT dual inhibition. The unique selectivity profile combined with acceptable in vivo PK/PD properties in the preclinical models makes compound 362 a valuable research tool for FLT3 medi- ated pathological study as well as a novel potential anti- FLT3-ITD+ AML drug candidate.
Aoli Wang,1,2* Chen Hu,1,2* Cheng Chen,1,3*
Xiaofei Liang,1,2* Beilei Wang,1,2* Fengming Zou,1,2 Kailin Yu,1 Feng Li,1,3 Qingwang Liu,2,4 Ziping Qi,1,2 Junjie Wang,1,3 Wenliang Wang,1,3 Li Wang,1,2 Ellen L. Weisberg,5 Wenchao Wang,1,2,3 Lili Li,6 Jian Ge,6 Ruixiang Xia,6
Jing Liu1,2,3# and Qingsong Liu1,2,3,4,7#
1High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui, P.R. China;
2Precision Medicine Research Laboratory of Anhui Province, Hefei, Anhui, P.R. China; 3University of Science and Technology of China, Hefei, Anhui, P.R. China; 4Precision Targeted Therapy Discovery Center, Institute of Technology Innovation, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui, P.R. China; 5Department of Medical Oncology, Dana Farber Cancer Institute, Harvard Medical School, Boston, MA, USA and 6Department of Hematology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, P.R. China and 7Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui, P.R. China
*AW, CH, CC, XL and BW contributed equally as co-first authors.
#Jing Liu and Qingsong Liu contributed equally as co-senior authors.
Correspondence:
QINGSONG LIU - qsliu97@hmfl.ac.cn JING LIU - jingliu@hmfl.ac.cn
doi:10.3324/haematol.2019.244186
Disclosures: no conflicts of interests to disclose.
Contributions: ALW, CH, CC, XFL, and BLW designed and performed the experiments; FMZ, KLY, FL, QWL, ZPQ, JJW, WWW, and LW aquired the data; ELW provided materials and reviewed the data. WCW reviewed the data and revised the manuscript. LLL, JG, and RXX collected the patient samples. JL and QSL designed the project and wrote the manuscript.
Acknowledgments: we are also grateful for the Youth Innovation Promotion Association of CAS support (n. 2016385) for XL and the support of Hefei leading talent for FZ. Part of this work was supported by the High Magnetic Field Laboratory of Anhui Province.
Funding: this work was supported by the National Natural Science Foundation of China (grant ns. 81773777, 81803366, 81872745, 81872748, 81673469), the “Personalized Medicines- Molecular Signature-Based Drug Discovery and Development”, Strategic Priority Research Program of the Chinese Academy of Sciences (grant n. XDA12020114), the National Science & Technology Major Project “Key New Drug Creation and Manufacturing Program” of China (grant n. 2018ZX09711002), the China Postdoctoral Science Foundation (grant ns. 2018T110634, 2018M630720, 2019M652057), the Postdoctoral Science Foundation of Anhui Province (grant ns. 2018B279, 2019B300, 2019B326), the Frontier Science Key Research Program of CAS (grant n. QYZDB-SSW-SLH037), the CASHIPS Director's Fund (grant n. BJPY2019A03), and the Key Program of 13th five-year plan of CASHIPS (grant n. KP-2017-26).
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