Recent developments in antibacterial or antibiofilm compound coating for biliary stents.

Cholestasis of the indwelling biliary stents usually leads to stone recurrence after endoscopic retrograde cholangio pancreatoraphy (ERCP). Biliary stents, including metallic and none-degradable plastic stents are widely used in clinical settings due to their many excellent properties. However, conventional biliary stents still suffer from poor antibacterial activity and anti-bile-adhesion, which lead to injured, local fibroblasts proliferating. Currently, various coatings for biliary stents have been prepared to meet the clinical demands. In this review, we start by summarizing and discussing classifications of biliary stents and antibacterial/antibiofilm mechanism. Then, the latest advances about developing antibacterial and antibiofilm coatings for improving the properties of biliary stents are reviewed and discussed in detail. Lastly, we list several possible directions for future development of biliary stents coatings and biliary stent, such as anti-bile-adhesion coating, multifunctional coating, drug-eluting biodegradable biliary stents and 3D printed biliary stents.

[Role of PRKCD and ASK1 in U937 cell differentiation].

OBJECTIVE: To investigate the expression of ASK1 and PRKCD in the process of monocyte differentiation, and explore their role in functional changes of hypersplenism spleen macrophages (Mφ) in portal hypertension (PH). METHODS: U937 cells were stimulated to differentiate into monocyte/macrophage-like cells by cultivation in PMA and the mRNA expressions of ASK1 and PRKCD were detected by q-PCR and the changes of protein expression were identified by western blot analysis. The secretion of phagocytose related cytokines such as IL-10 and TNF-α were tested by ELISA, and the function of the macrophage-like cells were studied by chicken red blood cell phagocytose test. RESULTS: The expressions of PRKCD and ASK1 mRNA were gradually decreased along with the cell differentiation, while the secretion of TNF-α was increased, IL-10 secretion reached a maximum at 24 h after PAM stimulation, and then gradually fell. The expression of ASK1 and p-ASK1 were rapidly increased compared with the non-stimulated U937 cells, while the expression of PRKCD and p-PRKCD were sightly declined. The phagocytose test show that U937 cells induced with PMA were able to swallow the chicken red blood cell. CONCLUSION: Up-regulated protein expression of ASK1 and p-ASK1 and down-regulated protein expression of PRKCD and p-PRKCD in the process of PMA induced monocyte differentiation, are consist with the expression changes of splenic macrophage phagocytosis in hypersplenism, which leads to increased activity of Mφ.

[Expressions of Bim and ERKs in multidrug-resistant hepatic carcinoma cells].

OBJECTIVE: To investigate the expressions of extracellular signal-regulated kinase (ERK) and the BH3-only subgroup of Bcl-2 related proteins (Bim) in multidrug-resistant hepatocellular carcinoma (HCC) cells and their association with drug resistance in the cells. METHODS: The multdrug-resistant HepG-2 cell line was established by treatment with gradually increasing doses of ADM. CCK-8 assay was used to determine the drug sensitivity of the cells, and the expressions of MRP-1, P-gp, ERK1, ERK2, ERK5, and Bim were detected with Western blot. Bim mRNA expression level was measured using quantitative real-time PCR. RESULTS: The drug resistance indices to ADM, 5-FU and CDDP was 6.8, 4.10, and 4.5 in HepG-2/ADM cells, respectively. The drug-resistantcells showed marked up-regulation of MRP-1, P-gp, ERK1, ERK2 and ERK5 with down-regulated phosphorylated ERK2 protein expression but no significant changes in phosphorylated ERK1 protein expression to result in a decreased ratio of P-ERK1/2 and P-ERK1/2. Bim mRNA and protein expressions were both decreased in HepG-2/ADM cells. CONCLUSION: ERK and Bim are related to multidrug resistance in HepG-2/ADM cells.

JNK1, JNK2, and JNK3 are involved in P-glycoprotein-mediated multidrug resistance of hepatocellular carcinoma cells.

BACKGROUND: Multidrug resistance (MDR) is extremely common in hepatocellular carcinoma (HCC) and is a major problem in cancer eradication by limiting the efficacy of chemotherapy. Modulation of c-Jun NH2-terminal kinase (JNK) activation could be a new method to reverse MDR. However, the relationship between JNK activity and MDR in HCC cells is unknown. This study aimed to explore the relationship between MDR and JNK in HCC cell lines with different degrees of MDR. METHODS: A MDR human HCC cell line, SMMC-7721/ADM, was developed by exposing parental cells to gradually increasing concentrations of adriamycin. The MTT assay was used to determine drug sensitivity. Flow cytometry was used to analyze the cell cycle distribution and to measure the expression levels of P-glycoprotein (P-gp) and MDR-related protein (MRP)-1 in these cells. JNK1, JNK2 and JNK3 mRNA expression levels were quantified by real-time PCR. Expression and phosphorylation of JNK1, JNK2, and JNK3 were analyzed by Western blotting. RESULTS: The MDR of SMMC-7721/ADM cells resistant to 0.05 mg/L adriamycin was mainly attributed to the overexpression of P-gp but not MRP1. In addition, these cells had a significant increase in percentage in the S phase, accompanied by a decrease in percentage in the G0/G1 phase, which is likely associated with a reduced ability for cell proliferation and MDR generation. We found that JNK1, JNK2, and JNK3 activities were negatively correlated with the degree of MDR in HCC cells. CONCLUSION: This study suggests that JNK1, JNK2, and JNK3 activities are negatively correlated with the degree of MDR in HCC cells.

Down-regulation of extracellular signal-regulated kinase 1/2 activity in P-glycoprotein-mediated multidrug resistant hepatocellular carcinoma cells.

AIM: To study the expression and phosphorylation of extracellular signal-regulated kinase (ERK) 1 and ERK2 in multidrug resistant (MDR) hepatocellular carcinoma (HCC) cells. METHODS: MDR HCC cell lines, HepG2/adriamycin (ADM) and SMMC7721/ADM, were developed by exposing parental cells to stepwise increasing concentrations of ADM. MTT assay was used to determine drug sensitivity. Flow cytometry was employed to analyze cell cycle distribution and measure cell P-glycoprotein (P-gp) and multidrug resistant protein 1 (MRP1) expression levels. ERK1 and ERK2 mRNA expression levels were measured by quantitative real-time PCR (QRT-PCR). Expression and phosphorylation of ERK1 and ERK2 were analyzed by Western blot. RESULTS: MTT assay showed that HepG2/ADM and SMMC7721/ADM were resistant not only to ADM, but also to multiple anticancer drugs. The P-gp expression was over 10-fold higher in HepG2/ADM cells than in HepG2 cells (8.92% +/- 0.22% vs 0.88% +/- 0.05%, P < 0.001) and over 4-fold higher in SMMC7721/ADM cells than in SMMC7721 cells (7.37% +/- 0.26% vs 1.74% +/- 0.25%, P < 0.001). However, the MRP1 expression was not significantly higher in HepG2/ADM and SMMC7721/ADM cells than in parental cells. In addition, the percentage of MDR HepG2/ADM and SMMC7721/ADM cells was significantly decreased in the G0/G1 phase and increased in the the S phase or G2/M phase. QRT-PCR analysis demonstrated that the ERK1 and ERK2 mRNA expression increased apparently in HepG2/ADM cells and decreased significantly in SMMC7721/ADM cells. Compared with the expression of parental cells, ERK1 and ERK2 protein expressions were markedly decreased in SMMC7721/ADM cells. However, ERK2 protein expression was markedly increased while ERK1 protein expression had no significant change in HepG2/ADM cells. Phosphorylation of ERK1 and ERK2 was markedly decreased in both HepG2/ADM and SMMC7721/ADM MDR cells. CONCLUSION: ERK1 and ERK2 activities are down-regulated in P-gp-mediated MDR HCC cells. ERK1 or ERK2 might be a potential drug target for circumventing MDR HCC cells.