Extracellular RNA transfer from non-malignant human cholangiocytes can promote cholangiocarcinoma growth.

Extracellular vesicles (EV) within the cellular secretome are emerging as modulators of pathological processes involved in tumor growth through their ability to transfer donor-derived RNA into recipient cells. While the effects of tumor and stromal cell EVs within the tumor microenvironment have been studied, less is known about the contributions of normal, nontransformed cells. We examined the impact of EVs within the cellular secretome from nonmalignant cells on transformed cell growth and behavior in cholangiocarcinoma cells. These effects were enhanced in the presence of the pro-fibrogenic mediator TGF-ß. We identified miR-195 as a TGF-ß responsive miRNA in normal cells that can be transferred via EV to tumor cells and regulate cell growth, invasion, and migration. The effects of miR-195 involve modulation of the epithelial-mesenchymal transition through direct effects on the transcription factor Snail. These studies provide in vitro and in vivo evidence for the impact of normal cellular secretome on transformed cell growth, show the importance of EV RNA transfer, and identify mechanisms of EV-mediated transfer of miRNA as a contributor to tumor development, which may provide new therapeutic opportunities for targeting human cholangiocarcinoma.

Extracellular vesicle-encapsulated miR-30e suppresses cholangiocarcinoma cell invasion and migration via inhibiting epithelial-mesenchymal transition.

Early-staged cholangiocarcinoma (CCA) is difficult to diagnose due to its high potential for invasion and metastasis. Epithelial-mesenchymal transition (EMT) is induced by transforming growth factor-ß (TGF-ß) in a process thought to be important for invasion and metastasis in several cancers, including CCA. Although microRNAs (miRNAs) have been implicated in the pathogenesis of several malignancies, their roles to CCA are not clearly understood. Some miRNAs were reported to be included in extracellular vesicles (EVs) and transferred from their donor cells to other cells, modulating recipient cell behaviors. In this study, the involvement and functional roles of EV-contained miRNAs during EMT in human CCA were determined. Expression profiling identified a subset of miRNAs that were reduced by TGF-ß in CCA cells. Among these, miR-30e was highly downregulated by TGF-ß and predicted to target Snail, which is an EMT-inducible transcription factor. MiR-30e overexpression suppressed cell invasion and migration via inhibiting EMT, whereas miR-30e inhibition promoted EMT, cell invasion and migration. Moreover, miR-30e was enriched in EVs derived from CCA cells after miR-30e overexpression, and miR-30e intercellular transfer through EVs suppressed EMT, cell invasion and migration in recipient CCA cells. Together, our results suggest that EV-mediated miR-30e transfer could inhibit EMT via directly targeting Snail, which subsequently suppresses CCA cell invasion and migration. These findings provide several new insights into regulatory mechanisms of tumor invasion and metastasis in human CCA.

Repeated administrations of concanavalin A induce Th1 to Th2 cytokine shift and tolerance against liver injury in mice.

The intravenous injection of concanavalin A (Con A) activates T cells and induces cytokine dependent liver injury in mice. However, the effect of repeated administrations of Con A has not been fully investigated. Female BALB/c mice were intravenously injected with Con A (20mg/kg) or saline once a week for six times. Mice were rechallenged with Con A 17 days after repeated administrations of Con A. Repeated Con A administrations elicited a sustained inhibition of rechallenged-Con A-induced liver injury. Plasma TNF-alpha and IFN-gamma levels after rechallenge of Con A were decreased compared with that of repeated saline treatments. By contrast, plasma IL-4 and IL-10 levels after rechallenge of Con A were increased. In spleen cells prepared from repeated Con A treated mice, the production of TNF-alpha and IFN-gamma 24h after co-incubation with Con A decreased, and that of IL-4 and IL-10 increased. In naive mice, plasma ALT level after Con A injection was decreased by the transfer of spleen cells prepared from the repeated Con A treated mice. The repeated administrations of Con A elicited Th1 to Th2 cytokine shift and the tolerant state against the Con A-induced liver injury in mice.

Inhibitory effect of angiotensin II receptor antagonist on hepatic stellate cell activation in non-alcoholic steatohepatitis.

AIM: To investigate the efficacy of angiotensin II receptor antagonist on hepatic stellate cells (HSCs) activation in the patients with non-alcoholic steatohepatitis (NASH). METHODS: Seven patients with NASH were prescribed losartan, a selective angiotensin II type 1 receptor antagonist (50 mg/d) for 48 wk. Liver biopsies were performed both at the entry and end of the study in all patients. Quiescent and activated HSCs were identified by double immunostaining using anti-p75 and -smooth muscle actin antibodies, and the number of each phenotype was counted. Similarly, the liver specimens obtained from the eight patients with non-alcoholic fatty liver (NAFL) were also examined as controls. RESULTS: In NASH hepatic tissues, activated HSCs were dominantly distributed as compared with those in NAFL. The 48-wk losartan treatment induced a remarkable decrease in activated HSCs and a mild increase in quiescent phenotypes. CONCLUSION: Our data suggest the crucial involvement of HSCs in anti-fibrotic effect of angiotensin II receptor antagonist on patients with NASH.

Angiotensin II type 1 receptor antagonist prevents hepatic carcinoma in rats with nonalcoholic steatohepatitis.

BACKGROUND: Angiotensin II type 1 receptor blockers (ARBs) have been reported to attenuate hepatic fibrosis in non-alcoholic steatohepatitis (NASH). However, it is uncertain whether ARBs prevent hepatocarcinogenesis in NASH even after hepatic fibrosis has developed. METHODS: Male Wistar rats were fed with a choline-deficient, L-amino acid-defined (CDAA) diet for 24 weeks, and then fed with the CDAA diet with telmisartan (2 mg/kg/day), a novel ARB, or vehicle for another 24 weeks. The liver histology and the expression of genes and proteins related to angiogenesis were investigated. RESULTS: The 24-week CDAA diet induced liver cirrhosis. The 48-week CDAA diet exacerbated liver cirrhosis, and developed hepatocellular carcinoma (HCC) in 54.6 % of the rats concurrently with increases of hypoxia-inducible factor-1α (HIF-1α) protein and vascular endothelial growth factor (VEGF) mRNA, which are potent angiogenic factors in the liver. Telmisartan inhibited hepatic fibrosis and preneoplastic lesions and prevented the development of HCC along with inducing decreases in HIF-1α protein and VEGF mRNA. CONCLUSIONS: These data indicated that telmisartan may prevent hepatocarcinogenesis through the inhibition of hepatic angiogenesis even after liver cirrhosis has been established.

Hepatic schwannoma: imaging findings on CT, MRI and contrast-enhanced ultrasonography.

A primary benign schwannoma of the liver is extremely rare and is difficult to preoperatively discriminate from a malignant tumor. We compared the imaging and pathological findings, and examined the possibility of preoperatively diagnosing a benign liver schwannoma. A 72-year-old woman was admitted to our hospital because of a 4.6-cm mass in the liver. A malignant tumor was suspected, and a right hepatectomy was performed. After this, the diagnosis of a primary benign schwannoma of the liver was made through pathological examination. Contrast-enhanced ultrasonography (CEUS) with Sonazoid showed minute blood flows into the septum and solid areas of the tumor in the vascular phase; most likely due to increased arterial flow associated with infiltration of chronic inflammatory cells. In the postvascular phase, CEUS showed contrast defect of cystic areas and delayed enhancement of solid areas; most likely due to aggregation of siderophores. Because discriminating between a benign and malignant schwannoma of the liver is difficult, surgery is generally recommended. However, the two key findings from CEUS may be useful in discriminating ancient schwannoma by recognizing the hemorrhage involved in the secondary degeneration and aggregation of siderophores.