Combination of Thymoquinone and Intermittent Fasting as a Treatment for Breast Cancer Implanted in Mice

Breast cancer stands out as a particularly challenging form of cancer to treat among various types. Traditional treatment methods have been longstanding approaches, yet their efficacy has diminished over time owing to heightened toxicity, adverse effects, and the emergence of multi-drug resistance. Nevertheless, a viable solution has emerged through the adoption of a complementary treatment strategy utilizing natural substances and the incorporation of intermittent fasting to enhance therapeutic outcomes. This study aimed to assess the anticancer activity of thymoquinone (TQ), intermittent fasting, and their combination using in vivo and in vitro methods. The anti-proliferative activity of TQ and fasting (glucose/serum restriction) were evaluated against the T47D, MDA-MB-231, and EMT6 cell lines and compared to normal cell lines (Vero) using the MTT colorimetric assay method. Additionally, this study aimed to determine the half-maximal inhibitory concentration (IC₅₀) of TQ. For the in vivo experiment, the antitumor activity of TQ and intermittent fasting (IF) was assessed by measuring the tumor sizes using a digital caliper to determine the change in the tumor size and survival rates. At the molecular level, the serum levels of glucose, β-hydroxybutyrate (β-HB), leptin, and insulin growth factor-1 (IGF-1) were measured using standard kits. Additionally, the aspartate transaminase (AST), alanine transaminase (ALT), and creatinine serum levels were measured. The inhibition of the breast cancer cell lines was achieved by TQ. TQ and intermittent fasting both had an additional anticancer effect against breast tumors inoculated in mice. The combination therapy was evaluated and found to significantly reduce the tumor size, with a change in tumor size of -57.7%. Additionally, the combination of TQ and IF led to a decrease in the serum levels of glucose, IGF-1 (24.49 ng/mL) and leptin (1.77 ng/mL) while increasing β-hydroxybutyrate in the mice given combination therapy (200.86 nM) with no toxicity on the liver or kidneys. In the mice receiving combination therapy, TQ and IF treated breast cancer in an additive way without causing liver or kidney toxicity due to decreased levels of glucose, IGF-1, and leptin and increased levels of β-hydroxybutyrate. Further investigation is required to optimize the doses and determine the other possible mechanisms exhibited by the novel combination.