Malformin A1 treatment alters invasive and oncogenic phenotypes of human colorectal cancer cells through stimulation of the p38 signaling pathway.

Malformin A1 (MA1), a cyclic pentapeptide isolated from Aspergillus niger, has been found to possess a range of bioactive properties including antibacterial activity. However, it is unclear whether MA1 exerts an anticancer effect or not. In this study, we conducted in vitro experiments to investigate its anticancer properties in human colorectal cancer cells. The effect of MA1 on human colorectal cancer cells, SW480 and DKO1, was examined by the WST-1 cell viability assay, inverted microscopy, 5-bromo-2-deoxyuridine (BrdU) incorporation, flow cytometry, DNA fragmentation, wound healing, Transwell assays, and western blotting. MA1 treatment showed potent cytotoxic activities on human colorectal cancer cells. MA1 treatment induced apoptosis by activating the poly(ADP-ribose) polymerase (PARP), caspase­3, -7, and -9. MA1 treatment led to the increase in p53 upregulated modulator of apoptosis (PUMA) and the decrease in X-linked inhibitor of apoptosis protein (XIAP) and Survivin. In addition, MA1 treatment induced cell cycle arrest in the sub-G1 phase. The pan-caspase inhibitor, Z­VAD­FMK, attenuated these MA1-induced apoptotic effects on human colorectal cancer cells. Moreover, MA1 treatment suppressed tumor cell migration and invasion. The phosphorylation level of p38 was upregulated by MA1 treatment, and the inhibitor of p38, SB203580, attenuated the MA1-induced p38 phosphorylation as well as caspase­3 and PARP activation. These results indicate that MA1 treatment alters invasive and oncogenic phenotypes of human colorectal cancer cells through the stimulation of the p38 signaling pathway.

The outcome of endoscopic management of bile leakage after hepatobiliary surgery.

BACKGROUND/AIMS: Despite improvements in surgical techniques and postoperative patient care, bile leakage can occur after hepatobiliary surgery and may lead to serious complications. The aim of this retrospective study was to evaluate the efficacy of endoscopic treatment of bile leakage after hepatobiliary surgery. METHODS: The medical records of 20 patients who underwent endoscopic retrograde cholangiopancreatography because of bile leakage after hepatobiliary surgery from August 2009 to September 2014 were reviewed retrospectively. Endoscopic treatment included insertion of an endoscopic retrograde biliary drainage stent after endoscopic sphincterotomy. RESULTS: Most cases of bile leakage presented as percutaneous bile drainage through a Jackson-Pratt bag (75%), followed by abdominal pain (20%). The sites of bile leaks were the cystic duct stump in 10 patients, intrahepatic ducts in five, liver beds in three, common hepatic duct in one, and common bile duct in one. Of the three cases of bile leakage combined with bile duct stricture, one patient had severe bile duct obstruction, and the others had mild strictures. Five cases of bile leakage also exhibited common bile duct stones. Concerning endoscopic modalities, endoscopic therapy for bile leakage was successful in 19 patients (95%). One patient experienced endoscopic failure because of an operation-induced bile duct deformity. One patient developed guidewire-induced microperforation during cannulation, which recovered with conservative treatment. One patient developed recurrent bile leakage, which required additional biliary stenting with sphincterotomy. CONCLUSIONS: The endoscopic approach should be considered a first-line modality for the diagnosis and treatment of bile leakage after hepatobiliary surgery.

Effect of Recepteur d'Origine Nantais expression on chemosensitivity and tumor cell behavior in colorectal cancer.

Recepteur d'Origine Nantais (RON) expression is known to induce oncogenic properties including tumor cell growth, survival, motility, angiogenesis and chemoresistance. In the present study, we evaluated whether RON affects chemosensitivity and oncogenic behavior of colorectal cancer cells and investigated its prognostic value in colorectal cancer. To evaluate the impact of RON on chemosensitivity and tumor cell behavior, we treated colorectal cancer cells with small interfering RNAs specific to RON. This was followed by flow cytometric analyses and migration, Matrigel invasion and endothelial tube formation assays. The expression of RON was investigated by immunohistochemistry in colorectal cancer tissues. TUNEL assay and immunohistochemical staining for CD34 and D2-40 were deployed to determine apoptosis, angiogenesis and lymphangiogenesis. RON knockdown enhanced 5-fluorouracil (FU)-induced apoptosis by upregulating the activities of caspases and expression of proapoptotic genes. Moreover, it enhanced 5-FU-induced cell cycle arrest by decreasing the expression of cyclins and cyclin­dependent kinases and inducing that of p21. Furthermore, RON knockdown augmented the 5-FU-induced inhibition of invasion and migration of colorectal cancer cells. The ß-catenin signaling cascade was blocked by RON knockdown upon 5-FU treatment. RON knockdown also decreased endothelial tube formation and expression of VEGF-A and HIF-1α and increased angiostatin expression. Furthermore, it inhibited lymphatic endothelial cell tube formation and the expression of VEGF-C and COX-2. RON expression was observed to be associated with age, tumor size, lymphovascular and perineural invasion, tumor stage, lymph node and distant metastasis, and poor survival rate. The mean microvessel density value of RON-positive tumors was significantly higher than that of RON-negative ones. These results indicate that RON is associated with tumor progression by inhibiting chemosensitivity and enhancing angiogenesis in colorectal cancer.

Myeloid cell leukemia-1 promotes epithelial-mesenchymal transition of human gastric cancer cells.

Epithelial-mesenchymal transition (EMT) is a critical process that occurs during cancer progression, and cancer stem cells have been shown to acquire the EMT phenotype. Myeloid cell leukemia-1 (Mcl-1) has been implicated in cancer progression and is overexpressed in a variety of human cancers. However, the interaction between Mcl-1 and EMT in human gastric cancer (GC) is unclear. We investigated the impact of Mcl-1 expression levels on EMT and the underlying signaling pathways in human GC cells. We used the human GC cell lines, AGS and SNU638, and small interfering RNAs (siRNAs) to evaluate the effects of Mcl-1 knockdown on cell adhesion, migration and invasion. Expression of Mcl-1 and other target genes was determined using reverse transcription-polymerase chain reaction assays and western blotting. The results revealed that expression levels of Mcl-1 mRNA and protein in the AGS and SNU638 cells were reduced following transfection with Mcl-1 siRNAs. Knockdown of Mcl-1 led to increased cellular adhesion to fibronectin and collagen. Expression levels of vimentin, MMP-2, MMP-9 and Snail protein were decreased following knockdown of Mcl-1. However, expression of E-cadherin was increased in the AGS cells following knockdown of Mcl-1. The expression of cancer stemness markers, such as CD44 and CD133, was not altered by knockdown of Mcl-1. Knockdown of Mcl-1 suppressed tumor cell migration and invasion in both human GC cell lines. Signaling cascades, including the ß-catenin, MEK1/2, ERK1/2 and p38 pathways, were significantly blocked by knockdown of Mcl-1. Our results indicate that Mcl-1 expression induces EMT via ß-catenin, MEK1/2 and MAPK signaling pathways, which subsequently stimulates the invasive and migratory capacity of human GC cells.