Although gemcitabine is the standard chemotherapy treatment for advanced pancreatic cancer, its benefits are quite limited due to prevalent chemoresistance, and the mechanism underlying gemcitabine chemoresistance remains unclear. Currently, Nrf2 has been deemed as a significant contributor to gemcitabine chemoresistance in pancreatic cancer. Brusatol is a unique inhibitor of the Nrf2 pathway, and in previous studies, we determined that brusatol exhibits the effects of growth inhibition and proapoptosis in pancreatic cancer cells. Due to these data, we speculate that brusatol can reverse gemcitabine‐induced Nrf2 activation and propose that it can enhance gemcitabine efficacy in treating pancreatic cancer. In this study, we first proved that brusatol can effectively inhibit the Nrf2 signalling pathway and increase ROS accumulation in pancreatic cancer cells. Next, we demonstrated that brusatol can abrogate gemcitabine‐induced Nrf2 activation in pancreatic cancer cells. In addition, we discovered that brusatol potentiates gemcitabine‐induced growth inhibition and apoptosis in human pancreatic cancer cells. In nude mice with PANC‐1 xenografts, treatment with a combination of brusatol and gemcitabine considerably reduced in vivo tumour growth compared with control treatment or treatment with either brusatol or gemcitabine alone. Immunohistochemical staining also showed that Nrf2 expression levels were reduced in brusatol‐treated xenograft tumour tissues. In summary, our results suggest that brusatol is capable of enhancing the antitumour effects of gemcitabine in both pancreatic cancer cells and PANC‐1 xenografts via suppressing the Nrf2 pathway.
15 August 2017 in Cellular Physiology and Biochemistry
Background/Aims: Pancreatic carcinoma (PC) is the one of the most common and malignant cancers worldwide. LncRNA taurine upregulated gene 1 (TUG1) was initially identified as a transcript upregulated by taurine, and the abnormal expression of TUG1 has been reported in many cancers. However, the biological role and molecular mechanism of TUG1 in PC still needs further investigation. Methods: Quantitative real-time PCR (qRT-PCR) was performed to measure the expression of TUG1 in PC cell lines and tissues. MTT and colony formation assays were used to measure the effect of TUG1 on cell proliferation. A wound healing assay, transwell assay and western blot assay were employed to determine the effect of TUG1 on cell migration and the epithelial mesenchymal transition (EMT) phenotype. RNA-binding protein immunoprecipitation (RIP) and a biotin-avidin pulldown system were performed to confirm the interaction between miR-328 and TUG1. A gene expression array analysis using clinical samples and RT-qPCR suggested that enhancer of zeste homolog 2 (EZH2) was a target of miR-382 in PC. Results: In this study, we reported that TUG1 was overexpressed in PC tissues and cell lines, and high expression of TUG1 predicted poor prognosis. Further experiments revealed that overexpressed TUG1 promoted cell proliferation, migration and contributed to EMT formation, whereas silenced TUG1 led to opposing results. Additionally, luciferase reporter assays, an RIP assay and an RNA-pulldown assay demonstrated that TUG1 could competitively sponge miR-382 and thereby regulate EZH2. Conclusion: Collectively, these findings revealed that TUG1 functions as an oncogenic lncRNA that promotes tumor progression, at least partially, by functioning as an endogenous ‘sponge’ and competing for miR-382 binding to the miRNA target EZH2.
Luteolin, a flavone, has been shown to exhibit anticancer properties. Here, we investigated whether luteolin affects epithelial–mesenchymal transition (EMT) and invasiveness of pancreatic cancer cell lines and their underlying mechanism. Pancreatic cancer cell lines PANC-1 and SW1990 were used in our study, and their EMT characters, matrix metalloproteinase (MMP) expression level, invasiveness, and signal transducer and activator of transcription 3 (STAT3) activity were determined after luteolin treatment. We also treated pancreatic cancer cells with interleukin-6 (IL-6) to see whether IL-6-induced activation of STAT3, EMT, and MMP secretion was affected by luteolin. We found that luteolin inhibits EMT and MMP2, MMP7, and MMP9 expression in a dose-dependent manner, similar to STAT3 signaling. Through Transwell assay, we found that invasiveness of pancreatic cancer cells was inhibited by luteolin. EMT characters and MMP secretion increase with STAT3 activity after IL-6 treatment and these effects, caused by IL-6, were inhibited by luteolin. We concluded that luteolin inhibits invasiveness of pancreatic cancer cells, and we speculated that luteolin inhibits EMT and MMP secretion likely through deactivation of STAT3 signaling. Luteolin has potential antitumor effects and merits further investigation.
Quercetin, a flavone, is multifaceted, having anti-oxidative, anti-inflammatory, and anticancer properties. In the present study, we explored the effects of quercetin on the epithelial–mesenchymal transition (EMT) and invasion of pancreatic cancer cells and the underlying mechanisms. We noted that quercetin exerted pronounced inhibitory effects in PANC-1 and PATU-8988 cells. Moreover, quercetin inhibited EMT and decreased the secretion of matrix metalloproteinase (MMP). Meanwhile, we determined the activity of STAT3 after quercetin treatment. STAT3 phosphorylation decreased following treatment with quercetin. We also used activating agent of STAT3, IL-6, to induce an increase in cell malignancy and to observe the effects of treatment with quercetin. As expected, the EMT and MMP secretion increased with activation of the STAT3 signaling pathway, and quercetin reversed IL-6-induced EMT, invasion, and migration. Therefore, our results demonstrate that quercetin triggers inhibition of EMT, invasion, and metastasis by blocking the STAT3 signaling pathway, and thus, quercetin merits further investigation.
1 January 2017 in Canadian Journal of Gastroenterology and Hepatology
Background and Aims. To investigate the association between serum albumin levels within 24 hrs of patient admission and the development of persistent organ failure in acute pancreatitis.Methods. A total of 700 patients with acute pancreatitis were enrolled. Multivariate logistic regression and subgroup analysis determined whether decreased albumin was independently associated with persistent organ failure and mortality. The diagnostic performance of serum albumin was evaluated by the area under Receiver Operating Characteristic (ROC) curves.Results. As levels of serum albumin decrease, the risk of persistent organ failure significantly increases (). The incidence of organ failure was 3.5%, 10.6%, and 41.6% in patients with normal albumin and mild and severe hypoalbuminaemia, respectively. Decreased albumin levels were also proportionally associated with prolonged hospital stay () and the risk of death (). Multivariate analysis suggested that biliary etiology, chronic concomitant diseases, hematocrit, blood urea nitrogen, and the serum albumin level were independently associated with persistent organ failure. Blood urea nitrogen and the serum albumin level were also independently associated with mortality. The area under ROC curves of albumin for predicting organ failure and mortality were 0.78 and 0.87, respectively.Conclusion. A low serum albumin is independently associated with an increased risk of developing of persistent organ failure and death in acute pancreatitis. It may also be useful for the prediction of the severity of acute pancreatitis.