Thymoquinone and pentoxifylline enhance the chemotherapeutic effect of cisplatin by targeting Notch signaling pathway in mice.

AIMS: Notch signaling is highly implicated in several cancers and chemoresistance. Therefore, Notch-targeted therapies might be beneficial in enhancing chemotherapeutic effect and cancer regression. This study aimed to investigate implication of Notch in development and progression of solid Ehrlich carcinoma (SEC) and enhancement of anticancer effect of cisplatin (CIS) by addition of thymoquinone (TQ) and pentoxifylline (PTX) through modulation of Notch. MAIN METHODS: SEC was induced in mice as model for mammary carcinoma by s.c. injection of 1 × 106 Ehrlich cells into back of the mice. On 12th day, solid tumor was developed and mice were divided into seven groups; tumor control, early CIS (ECIS), ECIS + ETQ, ECIS + ETQ + EPTX, late CIS (LCIS), LCIS + LTQ, and LCIS + LTQ + LPTX. Early treatment was started on 12th day, whereas late treatment was begun on 19th day from tumor inoculation. At the endpoint, samples were collected for detection of Notch1, Hes1, Jagged1, ß-catenin, TNF-α, IL-6, IFN-γ, IL-2, VEGF, apoptosis, CD4, and CD8. KEY FINDINGS: Adding PTX and TQ to CIS significantly reduced Notch1, Hes1, Jagged1, ß-catenin, TNF-α, IL-6, IFN-γ, and VEGF with increment in IL-2, CD4, CD8, and apoptotic cells. Moreover, early treated groups showed remarkable attenuation in tumor growth and the relevant parameters compared to their counterpart later groups. SIGNIFICANCE: Addition of PTX with TQ to CIS showed a synergistic chemotherapeutic action and induced better oncostatic effect mainly through Notch suppression. Consequently, shutting Notch could be of great interest in promoting chemosensetivity and cancer control.