Thymoquinone inhibits proliferation in gastric cancer via the STAT3 pathway in vivo and in vitro

Figure 1 Thymoquinone suppresses constitutive STAT3 activation in three gastric cancer cell lines. A: Human gastric cancer cells (HGC27, BGC823, and SGC7901) were incubated with 50 μmol/L thymoquinone (TQ) for 24 h, and western blotting was performed as described previously; B: The same blots were stripped and reprobed with the GAPDH antibody to verify equal protein loading; C: TQ suppressed phospho-STAT3 levels in a concentration- and time-dependent manner. HGC27 cells (1 × 10⁶/mL) were treated with the indicated concentrations of TQ for 24 h, and western blotting was performed (left). HGC27 cells (1 × 10⁶/mL) were treated with 50 μmol/L TQ for the indicated times, and western blotting was performed (right). The same blots were stripped and reprobed with the STAT3 antibody to verify equal protein loading; D: TQ suppressed STAT3 gene levels in a concentration- and time-dependent manner. HGC27 cells (1 × 10⁶/mL) were treated with the indicated concentrations of TQ for 24 h, and real-time RT-PCR was performed (left). HGC27 cells (1 × 10⁶/mL) were treated with 50 μmol/L TQ for the indicated times, and real-time RT-PCR was performed (right); E: TQ suppressed STAT3 nuclear translocation. HGC27 cells (1 × 10⁶/mL) cells were treated with or without 50 μmol/L TQ for 24h, and nuclear extracts were assessed for the detection nuclear accumulation of STAT3. Lamin-A was used as a nuclear extract marker. GAPDH: Glyceraldehyde-3-phosphate dehydrogenase; RT-PCR: Reverse transcription polymerase chain reaction; STAT: Signal transducer and activator of transcription.