Fig. 2
a Relative cell growth of T-ALL cell lines and normal T cell after treatment with various concentration of auranofin. Cell numbers were counted at 48 h post treatment with auranofin. b Auranofin-induced T-ALL cell death was attenuated by full-length TET1 overexpression. Data are mean ± SD (Two-tailed unpaired Student’s t test, **** p < 0.0001). c Auranofin-induced T-ALL cell death was attenuated by TET1-CD overexpression. Data are mean ± SD (Two-tailed unpaired Student’s t test, **** p < 0.0001). d Schematic of cell-derived xenograft (CDX) validating the in vivo anti-T-ALL activity. A total of 5 × 106 luciferase-expressing Jurkat cells were injected through the tail vein to NCG mice. Auranofin (20 mg/kg/2 days) was intraperitoneally administered from day 14 to day 28 with PBS as Vehicle. e Time-lapse bioluminescence imaging of the xenograft mice. f Quantification of the total photon flux of the xenograft mice at day 28. Data are mean ± SD (Two-tailed unpaired Student’s t test, ** p < 0.01). g Representative flow cytometry analysis of bone marrow resident Jurkat cancer cells in Vehicle and auranofin treated mice. Jurkat cancer cells were stained with anti-human CD7 antibody. h Quantification of the bone marrow resident Jurkat cancer cells shown in g. Two-tailed unpaired Student’s t test, *** p < 0.001. i Kaplan–Meier survival curves the xenograft mice treated with Vehicle or auranofin. j Venn diagram depicting vital genes which are intersected among 5hmC and RNA downregulated and 5mC upregulated genes. 31 intersected genes including c-Myc were identified. k Western blot analysis showing the time-dependent down-regulation of c-Myc expression in Jurkat and CCRF-CEM cells. l qRT-PCR analysis showing that c-Myc mRNA decreased after knockdown of TET1. m qRT-PCR analysis showing that c-Myc mRNA increased after overexpression of TET1. n Auranofin-induced T-ALL Jurkat cell death was attenuated by c-Myc overexpression at various auranofin concentrations. Data are mean ± SD (Two-tailed unpaired Student’s t test, **** p < 0.0001). o Schematic diagram showing the proposed mechanism of action of auranofin in T-ALL. Auranofin inhibits TET1 enzymatic activity through competitive occupation of the binding pocket to its cofactor substrates 2-oxoglutarate (2-OG) and Fe (II). Inhibition of TET1 subsequently down-regulated the transcription and translation of c-Myc, at least partially through c-Myc DNA epigenetic remodeling, leading to T-ALL cells death