Fig. 1

3-HAA induces apoptosis by binding with transcription factor YY1. A Quantitative analysis of tryptophan metabolites by LC–MS/MS and GC–MS in HCC and the corresponding paratumor tissues. **: P < 0.01. B Apoptosis analysis by TUNEL assay in SMMC7721 cells treated for 24 h with 3-HAA at the indicated dose. **: P < 0.01. C Apoptosis analysis by TUNEL assay and flow cytometry in SMMC7721 xenografts with and without 3-HAA treatment. The dose of 3-HAA was 100 mg/kg day. Mice were treated for seven days and sacrificed on day 10. *: P < 0.05. D The growth curve and representative photo of PCX xenografts. E The common proteins between 3-HAA-increased chromatin-binding proteins and predicted transcription factors binding to the top 4 genes’ promoter region. F The common proteins between 3-HAA-increased chromatin-binding proteins and predicted transcription factors binding to the promoter region of the top 4 genes. G YY1 knockdown abolished 3-HAA-induced DUSP6 expression. SMMC7721 cells were treated with 100 μM of 3-HAA for the indicated time. H The effect of YY1 knockdown on 3-HAA-induced HCC apoptosis, analyzed by flow cytometry. The concentration of 3-HAA was 100 μM. The **: P < 0.01. I YY1 depletion attenuated 3-HAA suppression of HCC tumor formation and shorten the survival of mice bearing transposon HCCs. The transposon genetic HCC mouse model was established as described in the section of Methods and Materials (n = 6). J The ChIP-sequencing analysis of YY1 on the DUSP6 and UGFBP1 genes. The HCC cells were treated with the indicated dose of 3-HAA prior to ChIP-sequencing. K 3-HAA binding to YY1 was determined by electrophoretic mobility shift assay (EMSA). The synthesized oligonucleotide was labeled at the 5' terminus with FAM, and YY1 was purified using a Hitrap heparin column. L NMR measurement of direct binding between 3-HAA and YY1. T1r NMR spectra for PBS (red) alone or in the presence of YY1 at 5 µM (green), or 8 µM (blue). The CPMG spectrum for 6b was recorded in the presence of 5 mM YY1