The objective of this research is to investigate the regulation of apoptotic associated-genes and proteins expression of aloe emodin on oestrogen receptor (ER)-positive (MCF-7). Oestrogen receptor (ER)-positive (MCF-7) cells were cultured in complete RPMI media. Cells were treated with aloe emodin at its IC50 of 80uM. Maximum treatment time was set for 72 hours in all assays. Both genes and proteins involved in the regulation of apoptosis (Fas, FADD, Caspase-3, Caspase-8, Caspase-9, Bax, Bcl-2, and Cytochrome c) in aloe emodin-treated MCF-7 were determined using Quantigene 2.0 Plex and protein ELISA assays respectively. Aloe emodin, previously reported as anti-cancer agent, was found to act as an apoptotic inducer on MCF-7 cells. In intrinsic apoptosis signalling, Bax, Cytochrome c and Caspase-9 proteins were upregulated (54.11% ± 4.51, 25.17% ± 4.13 and 36.05% ±11.75); while no change was observed in Bcl-2 protein. Except for Caspase-9, these results are in accordance with gene expression. In extrinsic apoptosis, Fas and Caspase-8 were upregulated (133.82% ± 2.85 and 26.44% ± 2.48), contrary to gene expression. These findings indicate that aloe emodin activates both extrinsic and intrinsic apoptosis pathways. The data suggests (i) aloe emodin has the potential to be a selective apoptotic inducer in ER+-breast cancer management; and (ii) the present study could be used as a basis for in vivo experiment.
Two-third of breast cancer patients expressed estrogen receptors (ER)s and received endocrine treatment with established anti-estrogens such as tamoxifen. But the action and acquired resistance during treatment are largely unknown. In contrary, phytochemicals are more selective and less cytotoxic to normal cells. Accordingly, we found aloe emodin, an anthraquinone to inhibit the proliferation of ER+-breast cancer cells, MCF-7 with IC50 of 80 µM, but not affecting control breast cells, MCF-10A. Tamoxifen was non-selective to both cells with IC50 of 27 and 38 μM, respectively. Thus, we aimed to investigate the anti-proliferative mechanism of aloe emodin on MCF-7 and its underlying signalling compared to tamoxifen. Cells were treated separately with aloe emodin and tamoxifen at respective IC50 for 72 h. Apoptosis was determined using Annexin V-FITC/PI staining. The expression of insulin-like growth factor-1 receptor (IGF-1R), insulin like growth factor binding protein (IGFBP)-2 and B-raf gene was investigated using QuantiGene 2.0 Plex assay. Pairedstudent t-test and ANOVA test were used to compare between untreated and treated cells on the measured parameters. Each treatment was conducted in triplicate and repeated three times. Significance was set at p<0.05. The presences of early and late apoptosis in MCF-7 were seen in both treatments. All target genes were down regulated. The anti-proliferation effect of aloe emodin on MCF-7 is similar with tamoxifen which mediates inhibition of IGF-1R signalling pathway. This suggests aloe emodin as a potential anti-cancer agent to be used in combined anti-estrogen therapy to enhance its efficacy in ER+-breast cancer treatment.