Crocin promotes apoptosis in human EBV-transformed b-lymphocyte via intrinsic pathway

Abstract

Background: As a major carotenoid in saffron, crocin demonstrates potent anti-cancer impacts. However, its anti-lymphoma effects remain vague, especially in the human EBV-associated B-cell lymphoproliferative disorders. This study examined crocin's apoptogenic potential and its underlying mechanism in CO 88BV59-1 cell line vs. normal human peripheral blood B cells. Methods: CO 88BV59-1 cells were treated with crocin alone or in combination with vincristine for up to 72 h. The cell viability was examined using a resazurin assay. Flow cytometry using annexin V and propidium iodide labeling was performed to detect apoptotic cells. Also, the expression levels of genes and proteins involved in apoptosis (CASP3, CASP8, CASP9, P53, Bax, and Bcl-2) were respectively determined via real-time PCR and Western blot analysis. Results: Crocin concentration-dependently reduced cell viability in CO 88BV59-1 cells with no significant toxicity toward normal B cells. Similar to vincristine, crocin significantly increased apoptosis in these cells during 72 h of incubation. Furthermore, the combination of crocin (80 μM) and vincristine (1 μM) enhanced apoptosis in CO 88BV59-1 cells. Therefore, this synergistic effect was detected in human EBV-transformed B-lymphocyte. CASP3, CASP9, P53, and Bax/Bcl-2 ratio expressions were significantly raised in CO 88BV59-1 cells, whereas CASP8 was unaltered. It was proposed that crocin promoted apoptosis in CO 88BV59-1 cells in a time- and concentration-dependent manner via the induction of the intrinsic pathway. Conclusion: The results suggest that crocin may serve as a good alternative/coadjuvant to vincristine in EBV-associated B-cell lymphoproliferative disorders.