The combined effect of survivin-targeted shRNA and emodin on the proliferation and invasion of ovarian cancer cells

Is Emodin with Anticancer Effects Completely Innocent? Two Sides of the Coin

Many anticancer active compounds are known to have the capacity to destroy pathologically proliferating cancer cells in the body, as well as to destroy rapidly proliferating normal cells. Despite remarkable advances in cancer research over the past few decades, the inclusion of natural compounds in researches as potential drug candidates is becoming increasingly important. However, the perception that the natural is reliable is an issue that needs to be clarified. Among the various chemical classes of natural products, anthraquinones have many biological activities and have also been proven to exhibit a unique anticancer activity. Emodin, an anthraquinone derivative, is a natural compound found in the roots and rhizomes of many plants. The anticancer property of emodin, a broad-spectrum inhibitory agent of cancer cells, has been detailed in many biological pathways. In cancer cells, these molecular mechanisms consist of suppressing cell growth and proliferation through the attenuation of oncogenic growth signaling, such as protein kinase B (AKT), mitogen-activated protein kinase (MAPK), HER-2 tyrosine kinase, Wnt/-catenin, and phosphatidylinositol 3-kinase (PI3K). However, it is known that emodin, which shows toxicity to cancer cells, may cause kidney toxicity, hepatotoxicity, and reproductive toxicity especially at high doses and long-term use. At the same time, studies of emodin, which has poor oral bioavailability, to transform this disadvantage into an advantage with nano-carrier systems reveal that natural compounds are not always directly usable compounds. Consequently, this review aimed to shed light on the anti-proliferative and anti-carcinogenic properties of emodin, as well as its potential toxicities and the advantages of drug delivery systems on bioavailability.

Dietary Phytochemicals as a Potential Source for Targeting Cancer Stem Cells

The tumor microenvironment is composed of various types of cells that lead to tumor heterogeneity. In the middle of these populations, cancer stem cells play a vital role in the initiation and progression of cancer cells and are capable of self-renewal and differentiation processes. These cancer stem cells are resistant to conventional therapy such as chemotherapy and radiotherapy. To eradicate the cancer stem cells in the tumor environment, various natural product has been found in recent years. In this review, we have selected some of the natural products based on anticancer potential including targeting cancer cells and cancer stem cells. Further, this review explains the molecular mechanism of action of these natural products in various cancer stem cells. Therefore, targeting a multi-drug resistant cancer stem cell by natural products is a novel method to reduce drug resistance and adverse effect during conventional therapy.

Emodin inhibits epithelial‑mesenchymal transition and metastasis of triple negative breast cancer via antagonism of CC‑chemokine ligand 5 secreted from adipocytes

Triple negative breast cancer (TNBC) has the lowest survival rate of the breast cancer subtypes owing to its aggressive and metastatic behavior. It has been reported that peritumoral adipose tissue contributes to the cell invasiveness and dissemination of TNBC. Emodin is an active anthraquinone derivative isolated from Rheum palmatum, with anticancer properties that have been reported to inhibit lung metastasis in a nude mouse xenograft model. In the present study, the effects of emodin on human TNBC cells and adipocytes were investigated in vivo and in vitro. The TNBC cell lines MDA‑MB‑231 and MDA‑MB‑453 were co‑cultured with human adipocytes and treated with either emodin or epirubicin. Cell proliferation was assessed by MTT assay and migration and invasion were examined using a wound healing assay and a Transwell assay. interleukin‑8, CC‑chemokine ligand 5 (CCL5) and insulin‑like growth factor‑1 levels in the culture supernatants were detected by ELISA. The epithelial‑mesenchymal transition (EMT) or metastasis associated markers were determined by western blot analysis. Nude mice fed with a high fat and sugar diet were used investigate the in vivo effect of emodin. The results showed that emodin inhibited TNBC proliferation and invasion more efficiently than epirubicin when co‑cultured with adipocytes by downregulating the level of CCL5 in adipocyte supernatants; inhibiting the expression level of protein kinase B (AKT); and activating glycogen synthase kinase‑3i (GSK3) and β‑catenin. This led to the suppressed expression of EMT‑ and invasion‑associated markers, including vimentin, snail, matrix metalloproteinase (MMP)‑2 and MMP‑9, and upregulation of E‑cadherin, contributing to the inhibition of invasion. The in vivo assay showed that emodin inhibited tumor growth, and suppressed the lung and liver metastasis of TNBC cells by decreasing the secretion of CCL5 in mice fed a high fat and sugar diet more efficiently when compared with epirubicin. In conclusion, emodin inhibited the secretion of CCL5 from adipocytes, inhibited the EMT of TNBC cells, and inhibited tumor growth and lung and liver metastasis, which indicated a novel role of emodin in preventing the metastasis of TNBC.

Artonin E Induces Apoptosis via Mitochondrial Dysregulation in SKOV-3 Ovarian Cancer Cells

Artonin E is a prenylated flavonoid isolated from the stem bark of Artocarpus elasticus Reinw.(Moraceae). This study aimed to investigate the apoptotic mechanisms induced by artonin E in a metastatic human ovarian cancer cell line SKOV-3 in vitro. MTT assay, clonogenic assay, acridine orange and propidium iodide double staining, cell cycle and annexin V analyses were performed to explore the mode of artonin E-induced cell death at different time points. DNA laddering, activation of caspases-3, -8, and -9, multi-parametric cytotoxicity-3 analysis by high-content screening, measurement of reactive oxygen species generation, and Western blot were employed to study the pathways involved in the apoptosis. MTT results showed that artonin E inhibited the growth of SKOV-3 cells, with IC50 values of 6.5±0.5 μg/mL after 72 h treatment, and showed less toxicity toward a normal human ovarian cell line T1074, with IC50 value of 32.5±0.5 μg/mL. Results showed that artonin E induced apoptosis and cell cycle arrest at the S phase. This compound also promoted the activation of caspases-3, -8, and -9. Further investigation into the depletion of mitochondrial membrane potential and release of cytochrome c revealed that artonin E treatment induced apoptosis via regulation of the expression of pro-survival and pro-apoptotic Bcl-2 family members. The expression levels of survivin and HSP70 proteins were also down regulated in SKOV-3 cells treated with artonin E. We propose that artonin E induced an antiproliferative effect that led to S phase cell cycle arrest and apoptosis through dysregulation of mitochondrial pathways, particularly the pro- and anti-apoptosis signaling pathways.

Emodin inhibits epithelial to mesenchymal transition in epithelial ovarian cancer cells by regulation of GSK-3β/β-catenin/ZEB1 signaling pathway

Emodin (EMO) has been shown to possess pleiotropic anticancer capabilities in many types of cancer, including epithelial ovarian cancer (EOC). Inhibitory efficacy of EMO on EOC invasion and migration was previously observed, however, the underlying mechanisms have not been completely elucidated. The present study is aimed to explore the mechanisms. Transwell assay demonstrated that EMO significantly inhibited A2780 and SK-OV-3 cell invasion. Western blot analysis was performed to detect the expression levels of epithelial to mesenchymal transition (EMT)-related markers. We found that EMO treatment dose-dependently upregulated E-cadherin, keratin and downregulated N-cadherin, vimentin, matrix metalloproteinase-9 (MMP-9) and matrix metalloproteinase-2 (MMP-2) to repress EMT. Mechanistically, EMO could inhibit glycogen synthase kinase 3β (GSK-3β) phosphorylation, decrease total β-catenin protein levels and subsequently downregulate transcription factor zinc finger E-box binding homeobox 1 (ZEB1) expression. These effects of EMO were weakened when the cells were pretreated with SB216763, an inhibitor of GSK-3β kinase. Besides, we utilized small interfering RNA (siRNA) to downregulate ZEB1 expression. We found that treatment of ZEB1-knockdown cells with EMO, ZEB1 levels were lowest and cell invasion was weakest but ZEB1 knockdown had no effect on the expression of phospho-Ser9-GSK-3β (p-GSK-3βSer9), β-catenin. In conclusion, our results suggested that EMO inhibited EOC cell invasion by regulation of GSK-3β/β-catenin/ZEB1 signaling pathway to suppress EMT in vitro.

Emodin induces apoptosis of human breast cancer cells by modulating the expression of apoptosis-related genes

The aim of this study was to investigate the effects of emodin on the proliferation of human breast cancer cells Bcap-37 and ZR-75-30. Cell viability following emodin treatment was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The effects of emodin on apoptosis were determined by flow cytometry using Annexin V-fluorescein isothiocyanate and propidium iodide staining. Quantitative polymerase chain reaction and western blot analysis were used to determine changes in the expression of apoptotic genes and protein, respectively. The effect of emodin on the invasiveness of breast cancer cells was evaluated by Matrigel invasion assay. Treatment of breast cancer cells Bcap-37 and ZR-75-30 with emodin was observed to inhibit the growth and induced apoptosis in a time- and dose-dependent manner. Emodin reduced the level of Bcl-2 and increased levels of cleaved caspase-3, PARP, p53 and Bax. These findings indicate that emodin induces growth inhibition and apoptosis in human breast cancer cells. Emodin may be a potential therapeutic agent for the treatment of breast cancer.