Simultaneous CK2/TNIK/DYRK1 inhibition by 108600 suppresses triple negative breast cancer stem cells

Triple negative breast cancer (TNBC) remains challenging because of heterogeneous responses to chemotherapy. Incomplete response is associated with a greater risk of metastatic progression. Therefore, treatments that target chemotherapy-resistant TNBC and enhance chemosensitivity would improve outcomes for these high-risk patients. Breast cancer stem cell-like cells (BCSCs) have been proposed to represent a chemotherapy-resistant subpopulation responsible for tumor initiation, progression and metastases. Targeting this population could lead to improved TNBC disease control. Here, we describe a novel multi-kinase inhibitor, 108600, that targets the TNBC BCSC population. 108600 treatment suppresses growth, colony and mammosphere forming capacity of BCSCs and induces G2M arrest and apoptosis of TNBC cells. In vivo, 108600 treatment of mice bearing triple negative tumors results in the induction of apoptosis and overcomes chemotherapy resistance.

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Fig: 108600 suppresses the growth of TNBC stem cells: A Chemical structure of 108600. B IC50 values for inhibition of 108600 target kinases. C 108600 inhibits phosphorylation of CK2α, DYRK1A and TNIK substrates. Lysates derived from MDA-MB-231 and Hs578T cells treated for 24 h with 108600 at the indicated concentrations were probed for expression of phospho-AKT1 (Ser129), phospho-CYCLIN D1 (Thr286), and AXIN2. The blots are representative of three independent experiments. Samples derive from the same experiment and the blots processed in parallel. D GI50 values for growth inhibition of breast cancer and normal cells treated with 108600. E Simultaneous siRNA-mediated knockdown of CK2α, DYRK1A, and TNIK suppresses proliferation of MDA-MB-231 and Hs578T cells. siRNA-transfected cells were counted on the indicated days. All data represent mean values ± standard deviation obtained from three independent biological replicates. The statistical difference between the target and nontarget siRNA treated groups was tested using two-way ANOVA (two-sided). Knockdown was confirmed by western blot analysis, which was performed three times. Samples derive from the same experiment and the blots processed in parallel. F 108600 treatment suppresses colony and G mammosphere formation of CD44high/CD24low stem cell fraction of MDA-MB-231 and Hs578T cells. For colony assays, CD44high/CD24low cells were purified by FACS, treated with the indicated concentrations of 108600 for 72 h, washed and allowed to grow for 7–14 days in drug-free medium. Cells were fixed with 4% paraformaldehyde in PBS, stained with crystal violet solution and colonies quantified microscopically. All data points represent mean value ± standard deviation. Scale bars = 50 µm. Values in F and G represent the mean percentage of colony and sphere formation ±SD, respectively, relative to that of DMSO, which was set to 100%, in three independent experiments. Source data are provided as a source data file.

Finally, treatment with 108600 and chemotherapy suppresses growth of pre-established TNBC metastases, providing additional support for the clinical translation of this agent to clinical trials.

Sato, K., Padgaonkar, A.A., Baker, S.J. et al. Simultaneous CK2/TNIK/DYRK1 inhibition by 108600 suppresses triple negative breast cancer stem cells and chemotherapy-resistant disease. Nat Commun 12, 4671 (2021). https://doi.org/10.1038/s41467-021-24878-z

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