Evaluating the Anti-Cancer Effects of Thymoquinone in Treating Colorectal Cancer In Vitro

Abstract

Abstract: Colorectal cancer (CRC) remains a significant health concern worldwide. The toxicities associated with the current treatment modalities for CRC and the growing emergence of chemotherapeutic resistance underscores the need for the discovery of novel anti-cancer agents that offer benefits in tackling these issues. Thymoquinone (TQ), a compound derived from Nigella sativa, has shown promising anticancer effects. This study aimed to investigate the anticancer properties of TQ against colorectal cancer (HCT-116) cells in vitro. The anti-cancer potential of TQ was evaluated using immunocytochemistry, cell cycle analysis, and Annexin V/PI apoptotic assay after 48 hours of treatment with TQ, 5-fluorouracil (5-FU) (positive control), and TQ + 5-FU. The results indicated a substantial reduction in (Epidermal growth factor receptor) EGFR expression post-TQ treatment (P ≤ 0.001). Similarly, increased expression of the apoptotic marker Caspase-3 was observed in cells treated with TQ (P ≤ 0.001), 5- FU (P ≤ 0.001), and their combination (P ≤ 0.001). Cell cycle analysis showed increased pre-G1 cell events in 5-FU (7.4%, P ≤ 0.05) and 5-FU + TQ (6.6%, P ≤ 0.05) with a slight elevation seen with TQ (1.7 %, P ≥0.05). Annexin V/PI apoptosis analysis further indicated that TQ-induced early apoptosis (9.15%) and late apoptosis (48.2%) and 5-FU + TQ had 14.5% and 24.8% respectively. In conclusion, Thymoquinone shows anticancer effects against colorectal cancer cells (HCT-116), decreasing EGFR expression and inducing apoptosis as evidenced by pre-G1 cell accumulation and elevated caspase-3 expression. While combined TQ and 5-FU treatment showed certain effects, it did not appear to enhance the anti-cancer activity of TQ or 5-FU, warranting further exploration.