The Effect and Mechanisms of Proliferative Inhibition of Crocin on Human Leukaemia Jurkat Cells

An In Vitro Study of Saffron Carotenoids: The Effect of Crocin Extracts and Dimethylcrocetin on Cancer Cell Lines

Crocus sativus L. has various pharmacological properties, known for over 3600 years. These properties are attributed mainly to biologically active substances, which belong to the terpenoid group and include crocins, picrocrocin and safranal. The aim of the current work was to examine the effects of crocins (CRCs) and their methyl ester derivate dimethylcrocetin (DMCRT) on glioblastoma and rhabdomyosarcoma cell lines, in terms of cytotoxicity and gene expression, implicated in proapoptotic and cell survival pathways. Cell cytotoxicity was assessed with Alamar Blue fluorescence assay after treatment with saffron carotenoids for 24, 48 and 72 h and concentrations ranging from 22.85 to 0.18 mg/mL for CRCs and 11.43 to 0.09 mg/mL for DMCRT. In addition, BAX, BID, BCL2, MYCN, SOD1, and GSTM1 gene expression was studied by qRT-PCR analysis. Both compounds demonstrated cytotoxic effects against glioblastoma and rhabdomyosarcoma cell lines, in a dose- and time-dependent manner. They induced apoptosis, via BAX and BID upregulation, MYCN and BCL-2, SOD1, GSTM1 downregulation. The current research denotes the possible anticancer properties of saffron carotenoids, which are considered safe phytochemicals, already tested in clinical trials for their health promoting properties.

Crocin Promotes Apoptosis in Human EBV-Transformed B-Lymphocyte via Intrinsic Pathway

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.

Antiangiogenic effect of crocin on breast cancer cell MDA-MB-231

Background

Crocin is the major chemical constituent of the Chinese herb saffron. A number of studies have indicated that crocin induces an antitumor effect by inhibiting proliferation and inducing the apoptosis of tumor cells. However, the effect of crocin on tumor angiogenesis remains unknown.

Methods

The effects of prolonged crocin exposure on breast cancer cell MDA-MB-231, human umbilical vein endothelial cells (HUVECs) and mice were examined.

Results

Crocin had a profound effect on the morphology and proliferation rate of MDA-MB-231 and HUVECs. Furthermore, crocin induced apoptosis and cell cycle arrest at the G2/M phase in MDA-MB-231 cells in a dose-dependent manner. This confirms that crocin induces the inhibition of HUVECs. Furthermore, the expression of CD34 in tumor tissues decreased after crocin treatment.

Conclusions

Crocin has an anti-angiogenesis effect that may be correlated to the decreased expression of CD34. Crocin is likely to be involved in the regulation of molecules in the angiogenesis pathway.

Crocin induces autophagic apoptosis in hepatocellular carcinoma by inhibiting Akt/mTOR activity

Background

Autophagy induction is a common mechanism for antitumor chemicals in induction of cancer cell death. However, the role of autophagy in crocin-induced apoptosis is barely studied in hepatocellular carcinoma (HCC).

Materials and methods

The influence of crocin on growth, apoptosis, and autophagy and its mutual relations were analyzed by Cell Counting Kit-8 assay, flow cytometer, EGFP-LC3 puncta analysis, and Western blot in HCC cells. The activities of Akt/mTOR axis and its roles in autophagy regulation were also detected by Western blot in HCC cells treated with crocin. Finally, the roles of Akt/mTOR axis in crocin-induced autophagic apoptosis were analyzed by Western blot and flow cytometer in HCC cells.

Results

The results showed that crocin can induce growth inhibition in a does- and time-dependent pattern by apoptosis. Increased LC3 puncta and upregulated LC3-II accumulation was observed as early as at 6 hours in HepG2 and HCCLM3 cells treated with 3 mg/mL crocin. Moreover, apoptosis analysis using flow cytometer and cleaved poly (ADP-ribose) polymerase detection revealed that autophagy initiation was prior to apoptosis activation in HCC cells treated with crocin. When autophagy was blocked with 3-methyladenine, crocin-induced apoptosis was inhibited in HCC cells. Furthermore, crocin treatment constrained the activities of key proteins in Akt/mTOR signaling, such as p-Akt (S473), p-mTOR (S2448), and p-p70S6K (T389), suggesting that crocin could induce autophagic apoptosis in HCC cells in an Akt/mTOR-dependent mechanism. Indeed, when autophagy was suppressed by forced expression of Akt, the crocin-induced apoptosis was also impaired in HCC cells.

Conclusion

The results suggested that crocin could induce autophagic apoptosis in HCC cells by inhibiting Akt/mTOR activity. This study originally revealed that autophagic apoptosis is a novel cytotoxic function of crocin, which lays the theoretical foundation for clinical application of crocin in HCC.