Kyohei Ariake

GCF2/LRRFIP1 promotes colorectal cancer metastasis and liver invasion through integrin-dependent RhoA activation

The precise relationship between GCF2 expression and carcinogenesis has not yet been established. To clarify the metastatic potential of GCF2 in colorectal cancer, HT-29 cells stably suppressing GCF2 expression were injected into the spleens of severe combined immunodeficient (SCID) mice. GCF2 suppression reduced the number of metastatic foci in the liver and reduced fibronectin-induced cell adhesion, migration, and invasion. Downstream from the integrin signaling pathways, GCF2 regulates RhoA interaction with the RGS domain of Leukemia associated RhoGEF (LARG). Altogether, our results suggest that GCF2 plays an important role in colorectal cancer metastasis by regulating RhoA-induced cell adhesion, migration, and invasion.

Silencing of LRRFIP1 reverses the epithelial–mesenchymal transition via inhibition of the Wnt/β-catenin signaling pathway

The canonical Wnt/β-catenin signaling pathway has been shown to promote the epithelial-mesenchymal transition (EMT), which is a crucial process in multiple embryonic developmental processes and the progression of carcinomas. We recently provided evidence that leucine-rich repeat flightless-1-interacting protein 1 (LRRFIP1) promotes cancer metastasis and invasion. In the present study, we identified the signaling elements targeted by LRRFIP1 for promotion of the EMT in pancreatic and lung cancer. LRRFIP1 silencing reversed the EMT, as shown by increased expression of E-cadherin (an epithelial marker) and decreased expression of vimentin (a mesenchymal marker). Silencing of LRRFIP1 up-regulated phosphorylation of β-catenin and decreased its nuclear localization by targeting the β-catenin destruction complex. The expression of β-catenin and E-cadherin in the plasma membrane fraction was increased in LRRFIP1 silenced cancer cells, and the migration and invasion capabilities were strongly inhibited. In addition, this protein was highly expressed at the invasion front of malignant tissue collected from pancreatic cancer patients. Consequently, our data strongly suggested that LRRFIP1 played an important role in the invasion of carcinoma cells. Our data provide experimental evidence that LRRFIP1 is an attractive candidate for targeted therapy in human cancers.

E-PASS comprehensive risk score is a good predictor of postsurgical mortality from comorbid disease in elderly gastric cancer patients

The long‐term prognosis of elderly gastric cancer patients is poor because of the cancer and unrelated comorbidities. We investigated the risk factors for mortality after gastrectomy to aid surgeons in deciding the correct operative procedure for elderly gastric cancer patients.

GC-binding factor 2 interacts with dishevelled and regulates Wnt signaling pathways in human carcinoma cell lines.

GC‐binding factor 2 (GCF2), a transcriptional repressor that decreases the activity of several genes is capable of binding directly to the GC‐rich sequence of the EGFR promoter and repressing the transcriptional activity of EGFR. In addition to its function as a transcriptional repressor, GCF2 can directly interact with other proteins such as flightless‐1 (Fli‐1). Many previous findings pertaining to the function of Fli‐1 have suggested a role for fli‐1 in providing a direct link between molecules involved in signal transduction pathways and the actin cytoskeleton. We hypothesized that GCF2, together with Fli‐1, plays a role in regulating cytoskeleton function, cell migration, and/or morphology. In our study, we observed that GCF2 is crucial for the activation of RhoA, a small GTPase that plays a key role in the regulation of the actin cytoskeleton. RhoA was markedly inactivated as a result of the decreased expression of GCF2. Co‐immunoprecipitations were subsequently performed to further investigate the mechanism for the repressive function. We identified dishevelled (Dvl), which is the key mediator for the Wnt pathway, as a binding partner with GCF2. These results strongly suggest that GCF2 plays a role in the Wnt‐noncanonical planar cell polarity (PCP) signaling pathway. Consequently, GCF2 may regulate the cytoskeleton or migration via Dvls and RhoA.

CLIC4 interacts with histamine H3 receptor and enhances the receptor cell surface expression

Histamine H3 receptor (H3R), one of G protein-coupled receptors (GPCRs), has been known to regulate neurotransmitter release negatively in central and peripheral nervous systems. Recently, a variety of intracellular proteins have been identified to interact with carboxy (C)-termini of GPCRs, and control their intracellular trafficking and signal transduction efficiencies. Screening for such proteins that interact with the C-terminus of H3R resulted in identification of one of the chloride intracellular channel (CLIC) proteins, CLIC4. The association of CLIC4 with H3R was confirmed in in vitro pull-down assays, coimmunoprecipitation from rat brain lysate, and immunofluorescence microscopy of rat cerebellar neurons. The data from flowcytometric analysis, radioligand receptor binding assay, and cell-based ELISA indicated that CLIC4 enhanced cell surface expression of wild-type H3R, but not a mutant form of the receptor that failed to interact with CLIC4. These results indicate that, by binding to the C-terminus of H3R, CLIC4 plays a critical role in regulation of the receptor cell surface expression.

FBXW7 modulates malignant potential and cisplatin-induced apoptosis in cholangiocarcinoma via NOTCH1 and MCL1

The ubiquitin ligase F‐box and WD repeat domain‐containing 7 (FBXW7) is responsible for degrading diverse oncoproteins and is considered a tumor suppressor in many human cancers. Inhibiting FBXW7 enhances the malignant potential of several cancers. In this study, we aimed to investigate the role of FBXW7 in cholangiocarcinoma. We found that FBXW7 expression was associated with clinicopathological outcomes in cholangiocarcinoma patients. Both disease‐free and overall survival were significantly worse in the low‐FBXW7 group than in the high‐FBXW7 group (P = .001 and P < .001, respectively). Multivariate analysis with the Cox proportional hazards model indicated that FBXW7 was the most important independent prognostic factor for disease‐free (P = .006) and overall (P = .0004) survival. We also showed that the two FBXW7 substrates, NOTCH1 and myeloid cell leukemia sequence 1 (MCL1), regulate cholangiocarcinoma progression. Depletion of FBXW7 resulted in NOTCH1 accumulation and increased cholangiocarcinoma cell migration and self‐renewal. Interestingly, when cells were stimulated with cis‐diamminedichloridoplatinum(II) (cisplatin), FBXW7 suppression induced MCL1 upregulation, which reduced the sensitivity of cholangiocarcinoma cells to apoptosis, indicating that FBXW7‐mediated ubiquitylation is context‐dependent. These results indicate that FBXW7 modulates the malignant potential of cholangiocarcinoma through independent regulation of NOTCH1 and MCL1.

Mo1693 Percutaneous Transhepatic Gallbladder Drainage Without Cholecystectomy Is Optimum Procedure in High-Risk Patients

Background: Intrahepatic stones are very uncommon in Western societies. In comparison, hepatolithiasis occurs more frequently in Southeast Asia because of the high prevalence of congenital biliary cysts and hepatobiliary parasites. Many Asian patients present with advanced disease which is usually managed with left hepatectomy. In North America both the underlying biliary pathology and the timing of presentation differ, but management has not been standardized, in part, because of the rarity of the disease. This analysis documents the etiology, presentation and outcomes of a transhepatic team approach for management of hepatolithiasis at a Western referral center. Methods: The records of patients with hepatolithiasis managed by interventional radiologists (IR) and surgeons from 2002 through 2012 were reviewed. Surgery was undertaken when required to repair the biliary pathology and/ or when the stone burden was extensive. All but one patient were managed with 20F transhepatic stent(s) placed either percutaneously or during surgery. Choledochoscopy was performed in almost all patients either percutaneously or intraoperatively to assist with stone removal. Laser lithotripsy and balloon dilation were undertaken for difficult stones and strictures. Transhepatic stents were removed when patients were stone and stricture free. A successful outcome was defined as stent removal without symptoms requiring more procedures. Results: Seventy-four patients were managed by IR alone (66%) or by IR and surgery (34%). The mean age was 55.6 years, and 51.4% were women. The majority of patients were Caucasian (80%), and only five (7%) were Asian. Underlying biliary pathology included benign strictures (55%), choledocholithiasis (22%), sclerosing cholangitis (12%), choledochal cysts (10%), and biliary parasites (1%). Twenty patients (27%) had biliary cirrhosis, and 17 of these patients developed hepatolithiasis after undergoing orthotopic liver transplantation. Fifteen additional patients (20%) had a prior biliary-enteric anastomosis. Upper abdominal pain (65%), cholangitis (47%) and jaundice (34%) were the most common presenting symptoms. The median number of IR procedures was 11, and choledochoscopy (88%) laser lithotripsy (68%) and balloon dilation (47%) were performed frequently. Surgical management included cholangioor hepatico-jejunostomy in 22 patients (88%) and hepatectomy in one (4%). Recurrent stone and stricture rates were both 26% and were managed with further biliary stenting. None of the patients have developed a cholangiocarcinoma with a median follow-up of 29 months. Conclusions: A combined interventional radiologic and surgical approach employing large bore transhepatic stents is a safe, but labor intensive, method for managing hepatolithiasis. This approach preserves hepatic parenchyma and prevents malignant degeneration.