Thymoquinone inhibits proliferation and impairs wound closure dynamics via apoptosis and autophagy-related pathways in multiple cancer cell lines

Abstract

Background Thymoquinone (TQ), the principal bioactive component of Nigella sativa, has attracted considerable attention for its potential anticancer properties. However, its antiproliferative effects and the underlying molecular mechanisms across different cancer cell types remain incompletely understood. Methods This study aimed to investigate the cytotoxic, antiproliferative, and antimigratory effects of TQ and to elucidate its role in apoptosis- and autophagy-related pathways in multiple cancer cell lines. Human liver (Hep3B), lung (A549), neuroblastoma (SH-SY5Y), and breast cancer (MCF-7) cells were treated with TQ at concentrations of 1-200 & micro;M for 24 and 48 h, while L929 fibroblast cells were used as a non-cancerous control. Cell viability was evaluated using the MTS assay, and wound closure, reflecting combined effects of cell migration and proliferation, was assessed using the wound healing assay. The expression levels of apoptosis- and autophagy-related genes (BAX, BCL2, CASP3, CASP8, CASP9, BECN1, SQSTM1, ATG5, and ATG7), as well as antiproliferative genes (TOB1, TOB2, BTG1, and BTG2), were analyzed by RT-PCR. Results TQ treatment significantly reduced cell viability in a dose- and time-dependent manner, with Hep3B and SH-SY5Y cells showing the highest sensitivity. Moreover, TQ markedly inhibited wound closure, particularly in Hep3B, A549, and MCF-7 cells. At the molecular level, TQ upregulated pro-apoptotic (BAX, CASPs) and autophagy-related (BECN1, ATG genes) markers while downregulating the anti-apoptotic gene BCL2. Additionally, the increased expression of TOB and BTG family genes supports their antiproliferative activity. Conclusions TQ exhibits broad-spectrum anticancer effects by suppressing proliferation and wound closure dynamics and inducing apoptosis and autophagy through gene regulatory mechanisms in a cell type-dependent manner. These findings provide mechanistic insights into the therapeutic potential of TQ in cancer treatment.