Crocetin induces cytotoxicity and enhances vincristine-induced cancer cell death via p53-dependent and -independent mechanisms

Aim: To investigate the anticancer effect of crocetin, a major ingredient in saffron, and its underlying mechanisms. Methods: Cervical cancer cell line HeLa, non-small cell lung cancer cell line A549 and ovarian cancer cell line SKOV3 were treated with crocetin alone or in combination with vincristine. Cell proliferation was examined using MTT assay. Cell cycle distribution and sub-G(1) fraction were analyzed using flow cytometric analysis after propidium iodide staining. Apoptosis was detected using the Annexin V-FITC Apoptosis Detection Kit with flow cytometry. Cell death was measured based on the release of lactate dehydrogenase (LDH). The expression levels of p53 and p21(WAF1/Cip1) as well as caspase activation were examined using Western blot analysis. Results: Treatment of the 3 types of cancer cells with crocetin (60-240 mu mol/L) for 48 h significantly inhibited their proliferation in a concentration-dependent manner. Crocetin (240 mu mol/L) significantly induced cell cycle arrest through p53-dependent and -independent mechanisms accompanied with p21(WAF1/Cip1) induction. Crocetin (120-240 mu mol/L) caused cytotoxicity in the 3 types of cancer cells by enhancing apoptosis in a time-dependent manner. In the 3 types of cancer cells, crocetin (60 mu mol/L) significantly enhanced the cytotoxicity induced by vincristine (1 mu mol/L). Furthermore, this synergistic effect was also detected in the vincristine-resistant breast cancer cell line MCF-7/VCR. Conclusion: Ccrocetin is a potential anticancer agent, which may be used as a chemotherapeutic drug or as a chemosensitizer for vincristine.