Emodin inhibits angiogenesis in pancreatic cancer by regulating the transforming growth factor-ß/drosophila mothers against decapentaplegic pathway and angiogenesis-associated microRNAs.

Emodin is a traditional Chinese medicine, which has been demonstrated to inhibit the growth of pancreatic cancer cells. However, the underlying molecular mechanisms remain to be elucidated. The present study investigated whether emodin suppresses angiogenesis in pancreatic cancer. A nude mouse pancreatic cancer xenograft model was established using SW1990 human pancreatic cancer cells by surgical orthotopic implantation. Different doses of emodin were injected into the abdominal cavities of the tumor­bearing mouse models and controls three times each week for 2 weeks. The tumors were measured and weighed, the expression of cluster of differentiation 34 was detected using immunochemistry, and microvessel densities were calculated. Reverse transcription­quantitative polymerase chain reaction (RT­qPCR) and western blotting were performed to determine the mRNA and protein expression levels of transforming growth factor (TGF)­ß and drosophila mothers against decapentaplegic (Smad) homologs. The angiogenesis­associated microRNAs (miR), miR­20, miR­155 and miR­210 were assessed by RT­qPCR. A negative dose­dependent association was revealed between treatment with emodin and the volume and weight of tumors and microvessel density. Emodin was associated with lower mRNA and protein expression levels of TGF­ß1 and its downstream target, angiopoietin­like 4, and higher mRNA and protein expression levels of TGF­ß receptor (TßR)I, TßRII and Smad4. Notably, treatment with emodin was associated with lower expression levels of miR­155 and miR­210 and higher expression levels of miR­20b. The present study suggested that treatment with emodin may repress angiogenesis in pancreatic cancer by altering the activities of the TGF-ß/Smad pathway and angiogenesis-associated miR-20b, miR-155, and miR-210.

Antiangiogenic effects of oxymatrine on pancreatic cancer by inhibition of the NF-κB-mediated VEGF signaling pathway.

Oxymatrine, the main alkaloid component in the traditional Chinese herbal medicine Sophora japonica (Sophora flavescens Ait), has been reported to have antitumor properties. However, the mechanisms of action in human pancreatic cancer are not well established to date. In the present study, we investigated the antiangiogenic effects of oxymatrine on human pancreatic cancer as well as the possible mechanisms involved. The results of the cell viability assay showed that treatment of PANC-1 pancreatic cancer cells with oxymatrine resulted in cell growth inhibition in a dose- and time-dependent manner. To investigate the possible mechanisms involved in these events, we performed western blotting and reverse transcription-polymerase chain reaction (RT-PCR) analysis. The results revealed that oxymatrine decreased the expression of angiogenesis-associated factors, including nuclear factor κB (NF-κB) and vascular endothelial growth factor (VEGF). Finally, the antiproliferative and antiangiogenic effects of oxymatrine on human pancreatic cancer were further confirmed in pancreatic cancer xenograft tumors in nude mice. In conclusion, our studies for the first time suggest that oxymatrine has potential antitumor effects on pancreatic cancer via suppression of angiogenesis, probably through regulation of the expression of the NF-κB-mediated VEGF signaling pathway.

Involvement of endoplasmic reticulum stress in capsaicin-induced apoptosis of human pancreatic cancer cells.

Capsaicin, main pungent ingredient of hot chilli peppers, has been shown to have anticarcinogenic effect on various cancer cells through multiple mechanisms. In this study, we investigated the apoptotic effect of capsaicin on human pancreatic cancer cells in both in vitro and in vivo systems, as well as the possible mechanisms involved. In vitro, treatment of both the pancreatic cancer cells (PANC-1 and SW1990) with capsaicin resulted in cells growth inhibition, G0/G1 phase arrest, and apoptosis in a dose-dependent manner. Knockdown of growth arrest- and DNA damage-inducible gene 153 (GADD153), a marker of the endoplasmic-reticulum-stress- (ERS-) mediated apoptosis pathway, by specific siRNA attenuated capsaicin-induced apoptosis both in PANC-1 and SW1990 cells. Moreover, in vivo studies capsaicin effectively inhibited the growth and metabolism of pancreatic cancer and prolonged the survival time of pancreatic cancer xenograft tumor-induced mice. Furthermore, capsaicin increased the expression of some key ERS markers, including glucose-regulated protein 78 (GRP78), phosphoprotein kinase-like endoplasmic reticulum kinase (phosphoPERK), and phosphoeukaryotic initiation factor-2 α (phospho-eIF2 α ), activating transcription factor 4 (ATF4) and GADD153 in tumor tissues. In conclusion, we for the first time provide important evidence to support the involvement of ERS in the induction of apoptosis in pancreatic cancer cells by capsaicin.

Antitumor and apoptosis-promoting properties of emodin, an anthraquinone derivative from Rheum officinale Baill, against pancreatic cancer in mice via inhibition of Akt activation.

Pancreatic adenocarcinoma is one of the most common malignancies worldwide. Gemcitabine is currently the standard first-line chemotherapeutic agent for pancreatic cancer. However, gemcitabine can induce activation of Akt and nuclear factor-κB (NF-κB), which is associated with its chemoresistance. It has been reported that gemcitabine combination therapies result in improved survival outcomes in pancreatic cancer. Therefore, agents that can either enhance the effects of gemcitabine or overcome chemoresistance to the drug are needed for the treatment of pancreatic cancer. Emodin is an active component of Chinese medicinal herbs and can inhibit the activation of Akt and NF-κB. In this study, we investigated whether emodin could enhance the anticancer effect of gemcitabine on pancreatic cancer in vivo. We demonstrated that treatment of gemcitabine combined with emodin efficiently suppressed tumor growth in mice inoculated with pancreatic tumor cells. This treatment paradigm promoted apoptotic cell death and mitochondrial fragmentation. Furthermore, it reduced phosphorylated-Akt (p-Akt) level, NF-κB activation and Bcl-2/Bax ratio, increased caspase-9 and -3 activation, Cytochrome C (CytC) release occurred in combination therapy. Collectively, emodin enhanced the activity of gemcitabine in tumor growth suppression via inhibition of Akt and NF-κB activation, thus promoting the mitochondrial-dependent apoptotic pathway. Therefore, our findings may provide new insights into understanding the pharmacological regulation of emodin on gemcitabine-mediated proapoptosis in pancreatic cancer and may aid in the design of new therapeutic strategies for the intervention of human pancreatic cancers.

[Effect of emodin combined gemcitabine on the growth and apoptosis of pancreatic cancer cell line BxPC-3 in vitro].

OBJECTIVE: To explore the effect of emodin combined gemcitabine (E&G) on human pancreatic cancer cell line BxPC-3 in vitro. METHODS: BxPC-3 cells were treated with emodin alone in different concentrations (0, 10, 20, 40, 80, and 160 micromol/L, respectively) for 24, 48, and 72 h, and E&G (emodin 40 micromol/L + gemcitabine 20 micromol/L) for 72 h. The inhibition on BxPC-3 cell proliferation was detected by Cell Counting Kit-8 assay and the cell apoptosis of BxPC-3 was determined using flow cytometry. RESULTS: Emodin obviously suppressed the proliferation of BxPC-3 cells in a dose- and time-dependent manner. The survival rates of BxPC-3 cells by 40 micromol/L emodin for 24, 48, and 72 h were 79. 39%, 46. 35%, and 45. 44%, respectively, while the survival rate of BxPC-3 cells acted by 72-h E&G was only 26. 62%, showing significant difference from that by gemcitabine alone (42.78%) and the emodin alone (47.18%). The early apoptotic ratio of BxPC-3 cells induced by 24 h emodin (40 micromol/L) and gemcitabine (20 micromol/L) were 4.70% +/- 1.54% and 11.20% +/- 1.41% respectively, while early apoptotic ratio of BxPC-3 cells induced by E&G was 20.60% +/-3.23%, showing significant difference from that induced by emodin or gemcitabine alone (P<0.05). CONCLUSIONS: Emodin could significantly inhibit BxPC-3 cell growth. It could act synergistically with gemcitabine to inhibit the tumor proliferation of BxPC-3 cells. Its synergistic action was achieved mainly through inducing pancreatic cancer cell apoptosis.

Effect of emodin in suppressing acute rejection following liver allograft transplantation in rats.

OBJECTIVE: To investigate the mechanism of action of emodin for suppressing acute allograft rejection in a rat model of liver transplantation. METHODS: Brown Norway (BW) recipient rats of orthotopic liver transplantation (OLT) were divided into three groups, Group A receiving isografting (with BW rats as donor), Group B receiving allografting (with Lewis rats as donor), Group C receiving allografting and emodin treatment (50 mg/kg daily). They were sacrificed on day 7 of post-transplantation, and their hepatic histology, plasma cytokine levels, and T-cell subset expression were detected. RESULTS: Compared with those in Group A, rats: in Group B exhibited severe allograft rejection with a rejection activity index (RAI) of 7.67+/-0.98, extensive hepatocellular apoptosis with an apoptosis index (AI) of 35.83+/-2.32, and elevated plasma levels of interleukin-2 (IL-2), interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-alpha), CD4(+) and CD4 CD4(+)/CD8(+) ratio. However, recipients in Group C showed a decrease in histological grade of rejection and hepatocellular apoptosis, as well as a decrease in plasma levels of IL-2, TNF-alpha, CD4(+) and CD4(+)/CD8(+) ratio, but elevated levels of IL-10 as compared with the allograft group. CONCLUSION: Post-OLT acute rejection could be attenuated by emodin, its mechanism of action may be associated with protecting hepatocytes from apoptosis, polarizing the Th 1 paradigm to Th2, and inhibiting the proliferation of CD4(+) T cell in plasma.