TGF-β downstream of Smad3 and MAPK signaling antagonistically regulate the viability and partial epithelial-mesenchymal transition of liver progenitor cells

BACKGROUND

Liver progenitor cells (LPCs) are a subpopulation of cells that contribute to liver regeneration, fibrosis and liver cancer initiation under different circumstances.

RESULTS

By performing adenoviral-mediated transfection, CCK-8 analyses, F-actin staining, transwell analyses, luciferase reporter analyses and Western blotting, we observed that TGF-β promoted cytostasis and partial epithelial-mesenchymal transition (EMT) in LPCs. In addition, we confirmed that TGF-β activated the Smad and MAPK pathways, including the Erk, JNK and p38 MAPK signaling pathways, and revealed that TGFβ-Smad signaling induced growth inhibition and partial EMT, whereas TGFβ-MAPK signaling had the opposite effects on LPCs. We further found that the activity of Smad and MAPK signaling downstream of TGF-β was mutually restricted in LPCs. Mechanistically, we found that TGF-β activated Smad signaling through serine phosphorylation of both the C-terminal and linker regions of Smad2 and 3 in LPCs. Additionally, TGFβ-MAPK signaling inhibited the phosphorylation of Smad3 but not Smad2 at the C-terminus, and it reinforced the linker phosphorylation of Smad3 at T179 and S213. We then found that overexpression of mutated Smad3 at linker phosphorylation sites intensifies TGF-β-induced cytostasis and EMT, mimicking the effects of MAPK inhibition in LPCs, whereas mutation of Smad3 at the C-terminus caused LPCs to blunt TGF-β-induced cytostasis and partial EMT.

CONCLUSION

These results suggested that TGF-β downstream of Smad3 and MAPK signaling were mutually antagonistic in regulating the viability and partial EMT of LPCs. This antagonism may help LPCs overcome the cytostatic effect of TGF-β under fibrotic conditions and maintain partial EMT and progenitor phenotypes.

Direct interaction of platelet with tumor cell aggravates hepatocellular carcinoma metastasis by activating TLR4/ADAM10/CX3CL1 axis

Metastasis is the main culprit of cancer-related death and account for the poor prognosis of hepatocellular carcinoma. Although platelets have been shown to accelerate tumor cell metastasis, the exact mechanism remained to be fully understood. Here, we found that high blood platelet counts and increased tumor tissue ADAM10 expression indicated the poor prognosis of HCC patients. Meanwhile, blood platelet count has positive correlation with tumor tissue ADAM10 expression. In vitro, we revealed that platelet increased ADAM10 expression in tumor cell through TLR4/NF-κB signaling pathway. ADAM10 catalyzed the shedding of CX3CL1 which bound to CX3CR1 receptor, followed by inducing epithelial to mesenchymal transition and activating RhoA signaling in cancer cells. Moreover, knockdown HCC cell TLR4 (Tlr4) or inhibition of ADAM10 prevented platelet-increased tumor cell migration, invasion and endothelial permeability. In vivo, we further verified in mice lung metastatic model that platelet accelerated tumor metastasis via cancer cell TLR4/ADAM10/CX3CL1 axis. Overall, our study provides new insights into the underlying mechanism of platelet-induced HCC metastasis. Therefore, targeting the TLR4/ADAM10/CX3CL1 axis in cancer cells hold promise for the inhibition of platelet-promoted lung metastasis of HCC.

m6A-regulated tumor glycolysis: new advances in epigenetics and metabolism

Glycolytic reprogramming is one of the most important features of cancer and plays an integral role in the progression of cancer. In cancer cells, changes in glucose metabolism meet the needs of self-proliferation, angiogenesis and lymphangiogenesis, metastasis, and also affect the immune escape, prognosis evaluation and therapeutic effect of cancer. The n6-methyladenosine (m6A) modification of RNA is widespread in eukaryotic cells. Dynamic and reversible m6A modifications are widely involved in the regulation of cancer stem cell renewal and differentiation, tumor therapy resistance, tumor microenvironment, tumor immune escape, and tumor metabolism. Lately, more and more evidences show that m6A modification can affect the glycolysis process of tumors in a variety of ways to regulate the biological behavior of tumors. In this review, we discussed the role of glycolysis in tumor genesis and development, and elaborated in detail the profound impact of m6A modification on different tumor by regulating glycolysis. We believe that m6A modified glycolysis has great significance and potential for tumor treatment.

Collagen I-DDR1 signaling promotes hepatocellular carcinoma cell stemness via Hippo signaling repression

Cancer stem cells (CSCs) are a minority population of cancer cells with stemness and multiple differentiation potentials, leading to cancer progression and therapeutic resistance. However, the concrete mechanism of CSCs in hepatocellular carcinoma (HCC) remains obscure. We found that in advanced HCC tissues, collagen I was upregulated, which is consistent with the expression of its receptor DDR1. Accordingly, high collagen I levels accompanied by high DDR1 expression are associated with poor prognoses in patients with HCC. Collagen I-induced DDR1 activation enhanced HCC cell stemness in vitro and in vivo. Mechanistically, DDR1 interacts with CD44, which acts as a co-receptor that amplifies collagen I-induced DDR1 signaling, and collagen I-DDR1 signaling antagonized Hippo signaling by facilitating the recruitment of PP2AA to MST1, leading to exaggerated YAP activation. The combined inhibition of DDR1 and YAP synergistically abrogated HCC cell stemness in vitro and tumorigenesis in vivo. A radiomic model based on T2 weighted images can noninvasively predict collagen I expression. These findings reveal the molecular basis of collagen I-DDR1 signaling inhibiting Hippo signaling and highlight the role of CD44/DDR1/YAP axis in promoting cancer cell stemness, suggesting that DDR1 and YAP may serve as novel prognostic biomarkers and therapeutic targets in HCC.

Locusta migratoria flight muscle troponin partially activates thin filament in a calcium-dependent manner

The troponin (Tn) complex, the sensor for Ca²⁺ to regulate contraction of striated muscle, is composed of three subunits, that is, TnT, TnI and TnC. Different isoforms of TnI and TnC are expressed in the thorax dorsal longitudinal muscle (flight muscle) and the hind leg extensor tibiae muscle (jump muscle) of the migratory locust, Locusta migratoria. The major Tn complexes in the flight muscle and the jump muscle are Tn-171 (TnT1/TnI7/TnC1) and Tn-153 (TnT1/TnI5/TnC3), respectively. Here, we prepared a number of recombinant Tn complexes and the reconstituted thin filaments, and investigated their regulation on thin filament. Although both Tn-171 and Tn-153 regulate thin filament in a Ca²⁺ -dependent manner, the extent of Ca²⁺ activation mediated by Tn-171 was significantly lower than that by Tn-153. We demonstrated that TnC1 and TnC3, rather than TnI5 and TnI7, are responsible for the different levels of the thin filament activation. Mutagenesis of TnC1 and TnC3 shows that the low level of TnC1-mediated thin filament activation can be attributed to the noncanonical residue Leu60 in the EF-hand-II of TnC1. We therefore propose that, in addition to Ca²⁺ , other regulatory mechanism(s) is required for the full activation of locust flight muscle.

18[Formula: see text]-Glycyrrhetinic Acid Inhibits TGF-[Formula: see text]-Induced Epithelial-to-Mesenchymal Transition and Metastasis of Hepatocellular Carcinoma by Targeting STAT3

18[Formula: see text]-glycyrrhetinic acid (GA) is the active ingredient of the traditional Chinese medicinal herb Glycyrrhizae radix et rhizoma. We previously demonstrated that GA inhibited tumor growth in hepatocellular carcinoma (HCC). However, the effect of GA on transforming growth factor-[Formula: see text] (TGF-[Formula: see text]-induced epithelial-mesenchymal transition (EMT) and metastasis were still unclear. In this study, in vitro transwell assays and immunofluorescence (IF) demonstrated that GA inhibited TGF-[Formula: see text]-induced migration, invasion and EMT of HCC cells. However, it had little effect on the inhibition of proliferation by TGF-[Formula: see text]. Moreover, we confirmed that GA suppressed the metastasis of HCC cells in vivousing an ectopic lung metastasis model. Furthermore, we found that GA inhibited TGF-[Formula: see text]-induced EMT mainly by reducing the phosphorylation of signal transducer and activator of transcription 3 (STAT3), which played an essential role in TGF-[Formula: see text]-induced EMT and cell mobility. Mechanistically, GA inhibited the phosphorylation of STAT3 by increasing the expression of Src homology 2 domain-containing protein tyrosine phosphatases 1 and 2 (SHP1 and SHP2). Therefore, we concluded that GA inhibited TGF-[Formula: see text]-induced EMT and metastasis via the SHP1&SHP2/STAT3/Snail pathway. Our data provide an attractive therapeutic target for future multimodal management of HCC.

Step-by-step Vascular Control for Extracapsular Resection of Complex Giant Liver Hemangioma Involving the Inferior Vena Cava

Massive hemorrhage remains an important clinical problem in extracapsular resection of giant liver hemangiomas (GLHs), especially for those involving the proximal hepatic veins and/or inferior vena cava. Between July 2004 and March 2012, 87 patients with a complex GLH scheduled for surgical treatment were included in this study. All patients were underwent vascular preparation (Step 1), advanced hepatic artery clamping (Step 2), and stepwise vascular occlusion (Step 3). Intraoperative blood loss, blood transfusion volume, degree of ischemia–reperfusion injury, and postoperative complications were recorded. No patients required urgent vascular preparation to manage intraoperative bleeding. In total, 87, 64, and 21 patients had portal triad (PT), infra-hepatic inferior vena cava (IVC), and suprahepatic IVC preparation; and 17, 43, and 11 patients had PT, PTand suprahepatic IVC, and all three (PT, infra-, and suprahepatic IVC) occlusions. The PT, infrahepatic IVC, and SIVC occlusion times were 12.1 ± 3.7 minutes, 7.9 ± 2.4 minutes, and 3.2 ± 1.4 minutes, respectively. Mean blood loss was 291.9 ± 124.5 mL, and only four patients received blood transfusions. No patients had life-threatening complications or died (Clavien-Dindo Grade 4, 5). Compared with paralleled studies, this technique has an advantage to decrease the blood loss in less liver ischemia time. For complex GLH resections, the described step-by-step vascular control technique was efficacious and feasible for controlling intraoperative bleeding.

Type-2 11β-hydroxysteroid dehydrogenase promotes the metastasis of colorectal cancer via the Fgfbp1-AKT pathway

Type-2 11β-hydroxysteroid dehydrogenase (HSD11B2) is a key enzyme which converts cortisol to inactive cortisone and is involved in tumor progression and metastasis. Several studies have shown that the promotion of tumor progression and metastasis by HSD11B2 resulted from its physiological function of inactivating glucocorticoids (GC). However, the underlying molecular mechanisms by which HSD11B2 drives metastasis, in addition to inactivating GC, are still unclear. In our study, a series of in vivo and in vitro assays were performed to determine the function of HSD11B2 and the possible mechanisms underlying its role in CRC metastasis. mRNA transcriptome array analysis was used to identify the possible downstream targets of HSD11B2. We found that the ectopic expression of HSD11B2 significantly promoted the migration, invasion and metastasis of colorectal cancer (CRC) cells both in vitro and in vivo, while it did not affect their proliferation in either case. Mechanically, HSD11B2 appeared to enhance cell migration and invasion by upregulating the expression of fibroblast growth factor binding protein 1 (Fgfbp1), and subsequently increasing the phosphorylation of AKT. Furthermore, AKT activation partially mediated the increased expression of Fgfbp1 induced by HSD11B2. HSD11B2 expression was positively correlated with Fgfbp1 and p-AKT expression in clinical samples of CRC. Additionally, knockdown of either Fgfbp1 or AKT impaired the migration and invasion capability of CRC cells with HSD11B2 overexpression, suggesting that HSD11B2 promoted the migration, invasion and metastasis of CRC cells via the Fgfbp1-AKT pathway. Therefore, targeting HSD11B2 or Fgfbp1 may be a novel treatment strategy for inhibiting the metastasis of CRC.

Correction to: Viral integration drives multifocal HCC during the occult HBV infection

In the original publication of this article [1], Fig. 6 is wrong and the updated figure is shown below.

TGF-β1 accelerates the hepatitis B virus X-induced malignant transformation of hepatic progenitor cells by upregulating miR-199a-3p

Increasing evidence has suggested that liver cancer arises partially from transformed hepatic progenitor cells (HPCs). However, the detailed mechanisms underlying HPC transformation are poorly understood. In this study, we provide evidence linking the coexistence of hepatitis B virus X protein (HBx) and transforming growth factor beta 1 (TGF-β1) with miR-199a-3p in the malignant transformation of HPCs. The examination of liver cancer specimens demonstrated that HBx and TGF-β1 expression was positively correlated with epithelial cell adhesion molecule (EpCAM) and cluster of differentiation 90 (CD90). Importantly, EpCAM and CD90 expression was much higher in the specimens expressing both high HBx and high TGF-β1 than in those with high HBx or high TGF-β1 and the double-low-expression group. HBx and TGF-β1 double-high expression was significantly associated with poor prognosis in primary liver cancer. We also found that HBx and TGF-β1 induced the transformation of HPCs into hepatic cancer stem cells and promoted epithelial–mesenchymal transformation, which was further enhanced by concomitant HBx and TGF-β1 exposure. Moreover, activation of the c-Jun N-terminal kinase (JNK)/c-Jun pathway was involved in the malignant transformation of HPCs. miR-199a-3p was identified as a significantly upregulated microRNA in HPCs upon HBx and TGF-β1 exposure, which were shown to promote miR-199a-3p expression via c-Jun-mediated activation. Finally, we found that miR-199a-3p was responsible for the malignant transformation of HPCs. In conclusion, our results provide evidence that TGF-β1 cooperates with HBx to promote the malignant transformation of HPCs through a JNK/c-Jun/miR-199a-3p-dependent pathway. This may open new avenues for therapeutic interventions targeting the malignant transformation of HPCs in treating liver cancer.

Outcomes and Prognostic Factors of Spontaneously Ruptured Hepatocellular Carcinoma

BACKGROUND

Spontaneous tumor rupture is a rare and life-threatening complication of hepatocellular carcinoma (HCC). The best treatment strategy remains unclear.

METHODS

The clinical data of 137 patients with spontaneously ruptured HCC from 2010 to 2015 were reviewed retrospectively. We investigated the outcome and prognostic factors of various treatment strategies.

RESULTS

Of the 137 patients, 53, 45, 3, and 36 patients underwent transcatheter arterial chemoembolization (TACE) alone, liver resection (LR) (LR alone or TACE + LR), surgical hemostasis, and conservative therapy. The patients undergoing LR had longest overall survival (OS). In the TACE alone group, independent factors affecting 30-day mortality were MELD score ≥ 12, AFP ≥ 1000 ng/ml, and largest tumor size ≥ 10 cm. AFP ≥ 1000 ng/ml, largest tumor size ≥ 10 cm, and no tumor capsule were significantly associated with poorer OS. In the LR group, largest tumor size ≥ 10 cm and no tumor capsule were the only independent prognostic factors for poorer OS and recurrence-free survival (RFS). Hypovolemic shock was an independent prognostic factor for poorer OS. The differences in OS between the TACE + LR group and LR alone group were not significant (P = 0.955). However, the RFS is significantly better in the LR alone group than those in the TACE + LR group (P = 0.031).

CONCLUSION

For resectable tumor, LR is the treatment of choice for patients with spontaneous ruptured HCC and preserved liver function. The delay in LR due to preoperative TACE may account for its worse RFS compared with LR alone. In patients with an unresectable tumor, TACE therapy alone improved survival over conservative therapy.

Viral integration drives multifocal HCC during the occult HBV infection

BACKGROUND & AIMS

Although the prognosis of patients with occult hepatitis B virus (HBV) infection (OBI) is usually benign, a small portion may undergo cirrhosis and subsequently hepatocellular carcinoma (HCC). We studied the mechanism of life-long Integration of virus DNA into OBI host's genome, of which may induce hepatocyte transformation.

METHODS

We applied HBV capture sequencing on single cells from an OBI patient who, developed multiple HCC tumors and underwent liver resection in May 2013 at Tongji Hospital in China. Despite with the undetectable virus DNA in serum, we determined the pattern of viral integration in tumor cells and adjacent non-tumor cells and obtained the details of the viral arrangement in host genome, and furthermore the HBV integrated region in cancer genome.

RESULTS

HBV captured sequencing of tissues and individual cells revealed that samples from multiple tumors shared two viral integration sites that could affect three host genes, including CSMD2 on chr1 and MED30/EXT1 on chr8. Whole genome sequencing further indicated one hybrid chromosome formed by HBV integrations between chr1 and chr8 that was shared by multiple tumors. Additional 50 poorly differentiated liver tumors and the paired adjacent non-tumors were evaluated and functional studies suggested up-regulated EXT1 expression promoted HCC growth. We further observed that the most somatic mutations within the tumor cell genome were common among the multiple tumors, suggesting that HBV associated, multifocal HCC is monoclonal in origin.

CONCLUSION

Through analyzing the HBV integration sites in multifocal HCC, our data suggested that the tumor cells were monoclonal in origin and formed in the absence of active viral replication, whereas the affected host genes may subsequently contribute to carcinogenesis.

Clinical Value of Trans-parenchymal Compressing Suture to Decrease the Cutting Surface Related Complications after Non-anatomical Liver Resection

Non-anatomical liver resection with appropriate resection margin is regarded as a potential curative treatment for selected major hepatic carcinoma due to preserving maximal normal liver, especially in cirrhotic patients. But occurrence of cutting surface related complications becomes a main challenge. From June 2010 to June 2016, 448 patients with major hepatic carcinoma received non-anatomical liver resection in our liver surgery center. After excluding 66 cases that were incongruent with the purpose of study, 235 patients undergoing transparenchymal compressing suture (TCS) to "not good" cutting surface were allocated as study group; 147 patients with exposed surface (ES) were matched as control group. The characteristics of postoperative drainage, postoperative hepatic and renal functions, hospital days, and outcomes were collected retrospectively. We further compared cutting surface related complications under different levels of liver cirrhosis between the two groups. Compared with ES group, patients in TCS group had a decreased incidence of cutting surface related complications (14.3% vs. 6.8%, P=0.011) and a decreased probability of interventions for cutting surface related complications (8.2% vs. 3.4%, P=0.042). TCS application was much more effective to prevent cutting surface related complications in patients with moderate and severe cirrhosis (5.4% vs. 15.8%, P=0.003). Postoperative hepatic and renal function, hospital days and mortality did not differ between the two groups. In conclusion, TCS decreases the probability of cutting surface related complications and postoperative interventions for related complications, especially in patients with moderate and severe cirrhosis.

FBXO22 promotes the development of hepatocellular carcinoma by regulating the ubiquitination and degradation of p21

BACKGROUND

Deregulation of ubiquitin ligases is related to the malignant progression of human cancers. F-box only protein 22 (FBXO22), an F-box E3 ligase, is a member of the F-box protein family. However, the biological function of FBXO22 in HCC and the underlying molecular mechanisms are still unclear. In this study, we explored the role of FBXO22 in HCC and its mechanism of promoting tumor development.

METHODS

We examined the expression of FBXO22 in normal liver cell lines, HCC cell lines, HCC tissue microarrays and fresh specimens. The correlation between FBXO22 and clinical features was analyzed in a retrospective study of 110 pairs of HCC tissue microarrays. Univariate and multivariate survival analyses were used to explore the prognostic value of FBXO22 in HCC. At the same time, the correlation between the FBXO22 and p21 was also studied in HCC samples. Knock-down and overexpression experiments, CHX and Mg132 intervention experiments, ubiquitination experiments, rescue experiments and nude mouse xenograft models were used to determine the potential mechanism by which FBXO22 promotes tumorigenesis in vitro and in vivo.

RESULTS

The expression of FBXO22 in HCC tissues was significantly higher than in normal liver tissues. The overall survival rate and disease-free survival time of patients with high expression of FBXO22 were significantly shorter than those of patients with low expression of FBXO22. The high expression of FBXO22 in HCC tissues were significantly correlated with serum AFP (p = 0. 003, Pearson's chi-squared test), tumor size (p = 0. 019, Pearson's chi-squared test) and vascular invasion (p = 0. 031, Pearson's chi-squared test). Especially, Multivariate analysis showed that tumor size and the expression of FBXO22 were independent prognostic indicator of OS (95% CI: 1.077-5.157, P<0.05). Correlation analysis also showed that FBXO22 was negatively correlated with p21 in tissue microarrays (r = - 0.3788, P<0.001, Pearson correlation) and fresh specimens (r = - 0.4037, P<0.01, Pearson correlation). Moreover, both in vitro and in vivo experiments showed that knocking down FBXO22 expression could inhibit cell proliferation, while overexpression of FBXO22 promoted tumor formation. Furthermore, we identified that FBXO22 interacts with p21 by regulating protein stability and by influencing the ubiquitination process. A knockdown of FBXO22 decreased the ubiquitylation of p21, while overexpression enhanced it.

CONCLUSIONS

This study uncovered a new mechanism by which FBXO22 functions as an oncogene in HCC pathogenesis and progression by mediating the ubiquitination and degradation of p21. It was also found that tumor size and the expression of FBXO22 were independent prognostic indicator of OS and the expression of FBXO22 and p21 was negatively correlated in clinical samples. Our findings present a new perspective for understanding the development of HCC, which may provide a new target for the treatment and management of this challenging cancer.

FAM134B induces tumorigenesis and epithelial-to-mesenchymal transition via Akt signaling in hepatocellular carcinoma

Fam134b (JK‐1, RETREG1) was first identified as an oncogene in esophageal squamous cell carcinoma. However, the roles of FAM134B during tumorigenesis of hepatocellular carcinoma (HCC) and in epithelial‐to‐mesenchymal transition (EMT) were previously unclear. In this study, we investigated the function of FAM134B in HCC and the related tumorigenesis mechanisms, as well as how FAM134B induces EMT. We detected the expression of FAM134B in a normal hepatic cell line, HCC cell lines, fresh specimens, and a HCC tissue microarray. A retrospective study of 122 paired HCC tissue microarrays was used to analyze the correlation between FAM134B and clinical features. Gain‐ and loss‐of‐function experiments, rescue experiments, Akt pathway activator/inhibitors, nude mice xenograft models, and nude mice lung metastasis models were used to determine the underlying mechanisms of FAM134B in inducing tumorigenesis and EMT in vitro and in vivo. The expression level of FAM134B was highly elevated in HCC, as compared with that in normal liver tissues and normal hepatic cells. Overexpression of FAM134B was significantly associated with tumor size (P = 0.025), pathological vascular invasion (P = 0.026), differentiation grade (P = 0.023), cancer recurrence (P = 0.044), and portal vein tumor thrombus (P = 0.036) in HCC. Patients with high expression of FAM134B had shorter overall survival and disease‐free survival than patients with non‐high expression of FAM134B. Furthermore, knockdown of FAM134B with shRNAs inhibited cell growth and motility, as well as tumor formation and metastasis in nude mice, all of which were promoted by overexpression of FAM134B. Our study demonstrated that Fam134b is an oncogene that plays a crucial role in HCC via the Akt signaling pathway with subsequent glycogen synthase kinase‐3β phosphorylation, accumulation of β‐catenin, and stabilization of Snail, which promotes tumorigenesis, EMT, and tumor metastasis in HCC.

Taurocholate Induces Connective Tissue Growth Factor Expression in Hepatocytes Through ERK-YAP Signaling

BACKGROUND/AIMS

Cholestasis is characterized by intrahepatic accumulation of cytotoxic bile acids (BAs), ultimately leading to fibrosis and cirrhosis, but the precise role of BAs in cholestasis-induced liver fibrosis remains largely elusive. In this study, we investigated the role and the potential mechanisms of BAs during cholestasis in vivo and in vitro.

METHODS

The effect of BAs during cholestasis was studied in bile duct ligation (BDL) rat models in vivo. We performed immunohistochemistry, Western blotting, and quantitative RT-PCR to investigate the expression of connective tissue growth factor (CTGF/CCN2) in rat liver during cholestasis. The hepatic cell lines AML12 and BRL were stimulated with taurocholate (TC) and the level of CTGF/CCN2, and activation of ERK, Akt, p38 MAPK, JNK, YAP, and TGF-β/Smad signaling were examined using Western blotting. Next, to elucidate the mechanism underlying bile acid-induced CTGF/CCN2, we treated the cells with MEK1/2 inhibitor (U0126), YAP function inhibitor (verteporfin), p38 kinase inhibitor (SB203580), Akt inhibitor (MK2206), and small interfering RNA (siRNA) targeting mek1, erk, and yap in cooperation with TC. Besides, we confirmed the activation of these signaling pathways in BDL and sham rat livers by immunohistochemistry, Western blotting, and quantitative RT-PCR.

RESULTS

In this study, we confirmed that the expression of CTGF/CCN2 was increased in BDL-induced rodent cholestatic liver fibrosis. In addition, we showed that TC, the main component of BAs, enhanced the synthesis of CTGF/ CCN2 in AML12 and BRL hepatic cell lines. Moreover, we demonstrated that TC activated ERK, Akt, and YAP signaling in hepatocytes, but the precise roles of these signaling cascades in the expression of CTGF/CCN2 were different: TC-induced expression of CTGF/CCN2 was mediated by ERK-YAP signaling, whereas Akt signaling inhibited ERK signaling and YAP and subsequently the expression of CTGF/CCN2 in hepatocytes. Furthermore, YAP functioned as a downstream regulator of ERK signaling in TC-induced CTGF/CCN2 expression in hepatocytes.

CONCLUSION

Our report provides evidence for the role of conjugated BAs in liver fibrosis and suggests that the production of CTGF/CCN2, induced by conjugated BAs via ERK-YAP axis activation, may be a therapeutic target in cholestasis-induced liver fibrosis.

Effect of surgical liver resection on circulating tumor cells in patients with hepatocellular carcinoma

BACKGROUND

This study explored the effect of liver resection on perioperative circulating tumor cells (CTCs) and found that the prognostic significance of surgery was associated with changes in CTC counts in patients with hepatocellular carcinoma (HCC).

METHODS

One hundred thirty-nine patients with HCC were consecutively enrolled. The time-points for collecting blood were one day before operation and three days after operation. CTCs in the peripheral blood were detected by the CellSearch™ System.

RESULTS

Both CTC detection incidence and mean CTC counts showed greater increases postoperatively (54%, mean 1.54 cells) than preoperatively (43%, mean 1.13 cells). The postoperative CTC counts increased in 41.7% of patients, decreased in 25.2% of patients and did not change in 33.1% of patients. The increase in postoperative CTC counts was significantly associated with the macroscopic tumor thrombus status. Patients with increased postoperative CTC counts (from preoperative CTC < 2 to postoperative CTC ≥ 2) had significantly shorter disease-free survival (DFS) and overall survival (OS) than did patients with persistent CTC < 2. Patients with persistent CTC levels of ≥2 had the worst prognoses.

CONCLUSIONS

Surgical liver resection is associated with an increase in CTC counts, and increased postoperative CTC numbers are associated with a worse prognosis in patients with HCC.

Rapamycin Upregulates Connective Tissue Growth Factor Expression in Hepatic Progenitor Cells Through TGF-β-Smad2 Dependent Signaling

Rapamycin (sirolimus) is a mTOR kinase inhibitor and is widely used as an immunosuppressive drug to prevent graft rejection in organ transplantation currently. However, some recent investigations have reported that it had profibrotic effect in the progression of organ fibrosis, and its precise role in the liver fibrosis is still poorly understood. Here we showed that rapamycin upregulated connective tissue growth factor (CTGF) expression at the transcriptional level in hepatic progenitor cells (HPCs). Using lentivirus-mediated small hairpin RNA (shRNA) we demonstrated that knockdown of mTOR, Raptor, or Rictor mimicked the effect of rapamycin treatment. Mechanistically, inhibition of mTOR activity with rapamycin resulted in a hyperactive PI3K-Akt pathway, whereas this activation inhibited the expression of CTGF in HPCs. Besides, rapamycin activated the TGF-β-Smad signaling, and TGF-β receptor type I (TGFβRI) serine/threonine kinase inhibitors completely blocked the effects of rapamycin on HPCs. Moreover, Smad2 was involved in the induction of CTGF through rapamycin-activated TGF-β-Smad signaling as knockdown completely blocked CTGF induction, while knockdown of Smad4 expression partially inhibited induction, whereas Smad3 knockdown had no effect. Rapamycin also induced ROS generation and latent TGF-β activation which contributed to TGF-β-Smad signaling. In conclusion, this study demonstrates that rapamycin upregulates CTGF in HPCs and suggests that rapamycin has potential fibrotic effect in liver.

18β-Glycyrrhetinic-acid-mediated unfolded protein response induces autophagy and apoptosis in hepatocellular carcinoma

18β-Glycyrrhetinic acid (GA) is the active ingredient of the traditional Chinese medicine, Glycyrrhrzae Radix et Rhizoma. Here, we explored the effects of GA on hepatocellular carcinoma (HCC) in vitro and in vivo and the underlying molecular mechanisms. We confirmed that GA suppressed proliferation of various HCC cell lines. Treatment of GA caused G0/G1 arrest, apoptosis and autophagy in HCC cells. GA-induced apoptosis and autophagy were mainly due to the unfolded protein response. We compared the roles of the ATF4/CHOP and IRE1α/XBP1s UPR pathways, which were both induced by GA. The ATF4/CHOP cascade induced autophagy and was indispensable for the induction of apoptosis in GA-treated HCC cells. In contrast, the IRE1α/XBP1s cascade protected HCC cells from apoptosis in vitro and in vivo induced by GA. Despite this, activation of autophagy protected HCC cells from apoptosis induced by GA. We concluded that pharmacological inhibition of autophagy or IRE1α may be of benefit to enhance the antitumor activity of GA.

IDH1 mutation correlates with a beneficial prognosis and suppresses tumor growth in IHCC

BACKGROUND

Isocitrate dehydrogenase 1/2 (IDH1/2) mutations have been reported in intrahepatic cholangiocarcinoma (IHCC). However, the prognosis of a single IDH1 mutation and impact of mutant IDH1 on IHCC tumor growth remain unclear.

METHODS

A total of 85 IHCC tumor samples were sequenced. Prognosis and clinicopathological correlation were analyzed. The role of mutant IDH1 in IHCC tumor growth was measured by cell proliferation assay, colony formation assay in soft agar, and xenograft tumor models. Akt, ERK, p38 MAPK, and JNK signaling, which commonly affect tumor growth, were examined by Western blotting to explore the potential mechanism.

RESULTS

IDH1 mutations correlated with a beneficial prognosis and smaller tumor size. Mutant IDH1 exhibited a growth-inhibitory effect on IHCC cell lines in vitro and in vivo. Akt signaling was suppressed in IHCC cell lines expressing a mutant IDH1. The reactivation of Akt signaling by SC79 restored the inhibited growth of cell lines expressing a mutant IDH1 in IHCC.

CONCLUSIONS

Collectively, we demonstrated that mutant IDH1 correlates with a beneficial prognosis and inhibits tumor growth by suppressing Akt signaling in IHCC. We suggest that patients with IDH1 mutations could be considered for both less-aggressive therapy and therapy tailored to the presence of their mutant enzyme in the future.

CRISPR/Cas9-mediated knockout of HBsAg inhibits proliferation and tumorigenicity of HBV-positive hepatocellular carcinoma cells

Chronic hepatitis B virus (HBV) infection remains the most common risk factor for hepatocellular carcinoma (HCC). High HBV surface antigen (HBsAg) levels are highly correlated with hepatocarcinogenesis and HBV‐associated HCC development. However, the role and detailed mechanisms associated with HBsAg in HCC development remain elusive. In this study, we designed specific single guide RNAs (sgRNAs) targeting the open reading frames, preS1/preS2/S, of the HBV genome and established HBsAg knockout HCC cell lines using the CRISPR/Cas9 system. We showed that knockout of HBsAg in HCC cell lines decreased HBsAg expression and significantly attenuated HCC proliferation in vitro, as well as tumorigenicity in vivo. We also found that overexpression of HBsAg, including the large (LHBs), middle (MHBs), and small (SHBs) surface proteins promoted proliferation and tumor formation in HCC cells. Moreover, we demonstrated that knockout of HBsAg in HCC cells decreased interleukin (IL)‐6 production and inhibited signal transducer and activator of transcription 3 (STAT3) signaling, while overexpression of HBsAg induced a substantial accumulation of pY‐STAT3. Collectively, these results highlighted the tumorigenic role of HBsAg and implied that the IL‐6‐STAT3 pathway may be implicated in the HBsAg‐mediated malignant potential of HBV‐associated HCC.

MicroRNA-630 suppresses tumor metastasis through the TGF-β- miR-630-Slug signaling pathway and correlates inversely with poor prognosis in hepatocellular carcinoma

The epithelial-mesenchymal transition (EMT) is the key process that drives tumor metastasis. Accumulating evidence suggests that the deregulation of some microRNAs (miRNAs), is implicated in this process. Here, we highlight the function and molecular mechanism of miR-630 and its potential clinical application in hepatocellular carcinoma (HCC). First, we identified the clinical relevance of miR-630 expression in a screen of 97 HCC patient tissues. Patients with low miR-630 expression had higher recurrence rates and shorter overall survival than those with high miR-630 expression. Functional studies demonstrated the overexpression of miR-630 in HCC cells attenuated the EMT phenotype in vitro. Conversely, inhibition of miR-630 promoted EMT in HCC cells. Mechanistically, our data revealed that miR-630 suppressed EMT by targeting Slug. Knockdown of Slug expression reversed miR-630 inhibitor-mediated EMT progression. Furthermore, we found that the TGF-β-Erk/SP1 and JNK/c-Jun signaling pathways repressed miR-630 transcription through occupying transcription factor binding sites. Ectopic expression of miR-630 restored the TGF-β-activated EMT process. Taken together, these findings demonstrate, in HCC cells, miR-630 exerts its tumor-suppressor functions through the TGF-β-miR-630-Slug axis and provides a potential prognostic predictor for HCC patients.

MicroRNA-199b-5p attenuates TGF-β1-induced epithelial-mesenchymal transition in hepatocellular carcinoma

Background:

Accumulating evidence indicates that N-cadherin is a cell adhesion molecule that has critical roles in tumour progression. However, the role of N-cadherin in hepatocellular carcinoma (HCC) remains controversial.

Methods:

This study aims to investigate the expression status of N-cadherin and its molecular mechanisms in HCC.

Results:

The expression of N-cadherin was markedly overexpressed in HCC tissues and cell lines. We identified that miR-199b-5p binds to the 3′-UTR of N-cadherin mRNA, thus decreasing N-cadherin expression in HCC cells. We also found the downregulation of miR-199b-5p in HCC specimens, which was inversely correlated with N-cadherin upregulation, predicted poor clinical outcomes in HCC patients. Next, we determined that miR-199b-5p overexpression promoted cell aggregation, suppressed cell migration and invasion in HCC cells, and inhibited xenografts tumour metastasis in nude mice. Moreover, we demonstrated that miR-199b-5p attenuated TGF-β1 induced epithelial–mesenchymal transition (EMT) -associated traits, while its effects could be partially reversed by N-cadherin restoration. Finally, we examined that N-cadherin downregulation or miR-199b-5p overexpression suppressed TGF-β1-induced Akt phosphorylation, and inhibition of PI3K/Akt pathway blocked TGF-β1-induced N-cadherin overexpression in HCC cells.

Conclusions:

Our data demonstrate that N-Cadherin was markedly overexpressed and miR-199b-5p was significantly downregulated in HCC. MiR-199b-5p exerts inhibitory effects on EMT, and directly targets N-cadherin in HCC, supporting the potential utility of miR-199b-5p as a promising strategy to treat HCC. Also, a positive regulatory loop exists between N-cadherin and Akt signalling represents a novel mechanism of TGF-β1-mediated EMT in HCC cells.

Hepatitis B virus X protein promotes CREB-mediated activation of miR-3188 and Notch signaling in hepatocellular carcinoma

Familiar clustering of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) has been frequently reported. However, limited information is available about the underlying molecular mechanisms in HBV-related HCC patients with family history of HCC. In our previous study, Agilent miRNA Base 16.0 microarray showed miRNA profiles of the plasma of HBV-related HCC patients who had a family history of HCC. This study aims to explore the expression, function, and mechanisms of miR-3188 in HCC that might provide novel insights into the role of family history on the risk of HCC. The expression levels of miR-3188 were markedly overexpressed in HCC tissues, HBV transgenic mice, and HepG2.215 cells. We knocked out miR-3188 in HCC cell lines using the CRISPR/Cas9 system, and demonstrated that miR-3188 knockout (KO) suppressed cell growth, migration, and invasion, and inhibited xenografts tumor growth in nude mice. Next, we determined that miR-3188 KO exerts antitumor functions by directly repressing ZHX2. It has been reported that HBV X protein (HBx) plays a critical role in HBV-related HCC, promoting CREB-mediated activation of miR-3188 and activation of Notch signaling through repressing ZHX2. Finally, we verified that ZHX2 functions as a transcriptional repressor to Notch1 via interaction with NF-YA. Our data demonstrate that the HBx–miR-3188–ZHX2-Notch1 signaling pathway plays an important role in the pathogenesis and progression of HBV-related HCC with family history of HCC. These findings have important implications for identifying new therapeutic targets in HBV-related HCC.

Loss of 11βHSD1 enhances glycolysis, facilitates intrahepatic metastasis, and indicates poor prognosis in hepatocellular carcinoma

11Beta-hydroxysteroid dehydrogenase type 1 (11βHSD1), converting glucocorticoids from hormonally inactive cortisone to active cortisol, plays an essential role in glucose homeostasis. Accumulating evidence suggests that enhanced glycolytic activity is closely associated with postoperative recurrence and prognosis of hepatocellular carcinoma (HCC). Whether 11βHSD1 contributes to HCC metastasis and recurrence remains unclear. Here we found that expression of 11βHSD1 in human HCC (310 pairs) was frequently decreased compared to the adjacent non-neoplastic liver tissues (ANT), which correlated well with the intrahepatic-metastatic index, serum glycemia, and other malignant clinicopathological characteristics of HCC and predicted poor prognosis. Knockdown of 11βHSD1 in BEL-7402 cells drastically reduced the pH of culture medium and induced cell death. Meanwhile, overexpression of 11βHSD1 in SMMC-7721 HCC cells resulted in repression of cell migration, invasion, angiogenesis, and proliferation in vitro. When transferred into BALB/c nude mice, 11βHSD1 overexpression resulted in decreased intrahepatic metastasis, angiogenesis, and tumor size. F-18-2-fluoro-2-deoxyglucose accumulation assay measured by positron emission tomography elucidated that 11βHSD1 reduced glucose uptake and glycolysis in SMMC-7721 cells in vitro, and intrahepatic metastasis foci and subcutaneous tumor growth in vivo. We showed that 11βHSD1 repressed cell metastasis, angiogenesis and proliferation of HCC by causing disruption of glycolysis via the HIF-1α and c-MYC pathways. In conclusion, 11βHSD1 inhibits the intrahepatic metastasis of HCC via restriction of tumor glycolysis activity and may serve as a prognostic biomarker for patients.

Indications for Administration of Parenteral Nutrition in Adults

BACKGROUND

Who benefits from parenteral nutrition (PN) has been the subject of much debate and 4 recent meta-analyses.

METHODS

We reviewed the 4 meta-analyses that examined the prospective, randomized, clinical trials (PRCT) that compared PN with no nutrition support (standard care) for design, study population, outcomes evaluated, and results.

RESULTS

Overall, a total of 113 PRCT were included in the 4 meta-analyses; however, only 4 studies were included in all of them. Despite the differences in populations studied and outcomes evaluated, some similarities emerged: (1) PN does not affect mortality; (2) PN does not reduce complications in normally nourished patients; (3) in malnourished patients, PN demonstrated a trend for reduced infections and complication rates; and (4) PN reduced postoperative complications in patients having surgery for cancer of the esophagus or stomach.

CONCLUSION

PN does not appear to be beneficial for most hospitalized patients. Among those with malnutrition or with upper gastrointestinal cancer, benefits may exist; however, these were influenced by quality of the study and year of publication.

c-Jun N-terminal kinase inhibitor favors transforming growth factor-β to antagonize hepatitis B virus X protein-induced cell growth promotion in hepatocellular carcinoma

Transforming growth factor (TGF)-β induces cell growth arrest in well-differentiated hepatocellular carcinoma (HCC) while hepatitis B virus X protein (HBx) minimizes the tumor suppression of TGF-β signaling in early chronic hepatitis B. However, how to reverse the oncogenic effect of HBx and sustain the tumor-suppressive action of TGF-β has yet to be investigated. The present study examined the effect of TGF-β and a c-Jun N-terminal kinase (JNK) inhibitor on cell growth in HCC cells with forced expression of HBx. It was found that HBx promoted cell growth via activation of the JNK/pSMAD3L pathway and inhibition of the transforming growth factor-beta type I receptor (TβRI)/pSMAD3C pathway. pSMAD3L/SMAD4 and pSMAD3C/SMAD4 complexes antagonized each other to regulate c-Myc expression. In the absence of HBx, TGF-β induced cell growth arrest through activation of the TβRI/pSMAD3C pathway in well-differentiated HCC cells. In the presence of HBx, TGF-β had no effect on cell growth. JNK inhibitor SP600125 significantly reversed the oncogenic action of HBx and favored TGF-β to regain the ability to inhibit the cell growth in HBx-expressing well-differentiated HCC cells. In conclusion, targeting JNK signaling favors TGF-β to block HBx-induced cell growth promotion in well-differentiated HCC cells. As an adjunct to anti-viral therapy, the combination of TGF-β and inhibition of JNK signaling is a potential therapy for HBV-infected HCC.

Abstract B47: Incomplete RFA-generated heat shock response provokes colorectal cancer liver metastases (CRLMs) recurrence by inducing cancer cell stemness and invasion

Even now, radiofrequency ablation (RFA) is accepted as a curative therapy for colorectal cancer liver metastasis (CRLMs). Accumulating data have shown that incomplete radiofrequency ablation (ICR) associates with increase of tumor recurrence and more aggressive malignant phenotype. We determined the mechanisms of this progression, including effectively predict biologic behaviors.We established a mouse model highly mimicking the process of RFA treatment. Functional studies were performed in vitro and in vivo. Our xenograft model unveiled ICR increases the risk in CRLMs recurrence. Here we focused on the heat shock (HS)-induced CRC malignance. Sublethal HS in CRC cell lines provoked cell growth, invasion, and tumor initiation in vitro. Consistently, the xenograft mouse model also confirmed the effects of HS in promoting tumor growth. With Western blot analysis, we found that Fra-1, which is a typical down-stream of the transcription factor ERK1/2, was significantly increased by heat shock stimuli compared with the untreated CRC cells. Furthermore, we demonstrated that silence of Fra-1 in HS treated cells could abolish the effects of HS in promoting malignant phenotype. Significantly, proliferation markers (Ki67, c-Myc, CyclinD1, CDK2), stem cell markers (Sox-2, Sox-9, Oct3/4, Lgr5) and invasion related MMP1 were up-regulated in the HS treated cells and in xenograft model. Taken together, this study established a novel mouse model to study the effect of ICR in CRLM. HS induces CRC proliferation and metastasis by targeting Fra-1, which is a potential prognostic marker and a promising therapeutic strategy for CRC recurrence after RFA treatment.

Citation Format: Zhan-Guo Zhang, Wan-Guang Zhang, Yan-Hui Wu, Hui-Fang Liang, Bi-Xiang Zhang, Xiao-Ping Chen. Incomplete RFA-generated heat shock response provokes colorectal cancer liver metastases (CRLMs) recurrence by inducing cancer cell stemness and invasion. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr B47.

PX-12 inhibits the growth of hepatocelluar carcinoma by inducing S-phase arrest, ROS-dependent apoptosis and enhances 5-FU cytotoxicity

BACKGROUND

1-methylpropyl 2-imidazolyl disulfide (PX-12), a thioredoxin 1 (Trx1) inhibitor, has been investigated in a number of ancers, but its effectiveness in the treatment of hepatocellular carcinoma (HCC) has not been reported. PX-12 has generated considerable interest in its use in a variety of solid tumors, yet most studies have confined their interests to using PX-12 as a single agent. The aim of this study is to investigate whether PX-12 inhibits cell growth and has a synergistic anti-tumor effect in combination with 5-fluorouracil (5-FU) in HCC.

METHODS

Cells were treated with different concentrations of PX-12 and 5-FU. Cell viability assays, colony formation assay, cell cycle assay, reactive oxygen species (ROS) assay, apoptosis analysis, western blot assay, immunohistochemistry and xenograft tumorigenicity assay were performed.

RESULTS

Treatment with PX-12 inhibited cell growth, induced S-phase arrest, and increased ROS levels. PX-12-induced apoptosis and inhibition of colony formation were associated with the generation of ROS, and inhibition of ROS attenuated PX-12-induced apoptosis and inhibition of colony formation. Treatment with PX-12 increased the expression of bax and reduced the expression of bcl-2, indicating that PX-12-mediated apoptosis is mitochondria-dependent. PX-12 also exerted a synergistic effect with 5-FU tosignificantly suppress tumorigenicity both in vitro and in vivo. Inhibition of ROS accumulation reduced the synergistic effect of PX-12 and 5-FU.

CONCLUSIONS

PX-12 has anti-tumor activity and a synergistic effect in combination with 5-FU in HCC. Treatment with PX-12 alone or in combination with 5-FU may have clinical use in the treatment of HCC and other cancers.

Animal and cellular models of hepatocellular carcinoma bone metastasis: establishment and characterisation

BACKGROUND

An increasingly high occurrence of bone metastases in hepatocellular carcinoma (HCC) patients highlights the importance of fundamental research on HCC bone metastasis, which has been limited in its success due to the lack of a model system.

PURPOSE

Establishment of animal and cellular models of HCC bone metastasis and discovery of HCC bone metastasis-related genes.

METHODS

Luciferase-transfected HCC cell lines HCCLM3, MHCC97H, and SMMC-7721 were used to inoculate nude mice intracardially. Formation of bone metastases was examined by bioluminescence imaging, SPECT, and pathology study. Metastatic cells in bone were isolated and subcultured. Differences between bone metastatic cells and their parental cells were studied by in vitro/in vivo assays.

RESULTS

Mouse model of HCC bone metastasis was successfully established. Injected tumour cells formed metastases in the skull, the spine, the hind limbs, and the sternum, causing osteolytic lesions via act of MMP-1 and recruitment of osteoclasts. Four bone metastatic cell lines were extracted from HCCLM3-inoculated mice and were demonstrated to exhibit a much stronger ability to form bone metastases as well as other phenotypes, including enhanced in vitro migration/invasion and colony formation. Moreover, the expression of PTHrP, MMP-1, and CTGF was significantly elevated in bone metastatic cells compared to parental HCC cells.

CONCLUSION

The nude mouse model and bone metastatic cell lines together provide an effective simulation of HCC bone metastasis. This model system will become powerful tool with which to explore the mechanisms and therapies of HCC bone metastasis. Additionally, PTHrP, MMP-1, and CTGF are candidate genes related to HCC bone metastasis.

MiR-132 prohibits proliferation, invasion, migration, and metastasis in breast cancer by targeting HN1

Accumulating evidence indicates that miRNAs play critical roles in tumorigenesis and cancer progression. This study aims to investigate the role and the underlying mechanism of miR-132 in breast cancer. Here, we report that miR-132 is significantly down-regulated in breast cancer tissues and cancer cell lines. Additional study identifies HN1 as a novel direct target of miR-132. MiR-132 down-regulates HN1 expression by binding to the 3' UTR of HN1 transcript, thereby, suppressing multiple oncogenic traits such as cancer cell proliferation, invasion, migration and metastasis in vivo and in vitro. Overexpression of HN1 restores miR-132-suppressed malignancy. Importantly, higher HN1 expression is significantly associated with worse overall survival of breast cancer patients. Taken together, our data demonstrate a critical role of miR-132 in prohibiting cell proliferation, invasion, migration and metastasis in breast cancer through direct suppression of HN1, supporting the potential utility of miR-132 as a novel therapeutic strategy against breast cancer.

Smad6 suppresses the growth and self-renewal of hepatic progenitor cells

Activation of hepatic progenitor cells (HPCs) is commonly observed in chronic liver disease and Wnt/β-catenin signaling plays a crucial role in the expansion of HPCs. However, the molecular mechanisms that regulate the activation of Wnt/β-catenin signaling in the liver, especially in HPCs, remain largely elusive. Here, we reported that ectopic expression of Smad6 suppressed the proliferation and self-renewal of WB-F344 cells, a HPC cell line. Mechanistically, we found that Smad6 inhibited Wnt/β-catenin signaling through promoting the interaction of C-terminal binding protein (CtBP) with β-catenin/T-cell factor (TCF) complex to inhibit β-catenin mediated transcriptional activation in WB-F344 cells. We used siRNA targeting β-catenin to demonstrate that Wnt/β-catenin signaling was required for the proliferation and self-renewal of HPCs. Taken together, these results suggest that Smad6 is a regulatory molecule which regulates the proliferation, self-renewal and Wnt/β-catenin signaling in HPCs.

HBx protein promotes oval cell proliferation by up-regulation of cyclin D1 via activation of the MEK/ERK and PI3K/Akt pathways

Growing evidence has shown that hepatic oval cells, also named liver progenitor cells, play an important role in the process of liver regeneration in various liver diseases. Oval cell proliferation has been reported in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) and chronic liver disease. Studies have found expression of HBV surface and core antigens in oval cells in the livers of patients with HCC, suggesting that HBV infection of oval cells could be a mechanism of human hepatocarcinogenesis. In addition, there is evidence of multiplication of HBV in oval cell culture. However, little research has been performed to explore the role of HBV-encoded proteins in the proliferation of hepatic oval cells. Previously, we successfully transfected the HBV x (HBx) gene, one of the four genes in the HBV genome, into a rat LE/6 oval cell line. In this study, we tested whether or not the transfected HBx gene could affect oval cell proliferation in vitro. Our results show that overexpression of HBx promotes the proliferation of oval cells and increases cyclin D1 expression, assessed at both the mRNA and protein levels. We also found that HBx activated the PI-3K/Akt and MEK/ERK1/2 pathways in HBx-transfected oval cells. Furthermore, the HBx-induced increases in cyclin D1 expression and oval cell proliferation were completely abolished by treatment with either MEK inhibitor PD184352 or PI-3K inhibitor LY294002. These results demonstrated that HBx has the ability to promote oval cell proliferation in vitro, and its stimulatory effects on cell proliferation and expression of cyclin D1 depend on the activation of the MEK/ERK and PI3K/Akt signaling pathways in cultured oval cells.

Step-by-step vascular control for extracapsular resection of complex giant liver hemangioma involving the inferior vena cava

Massive hemorrhage remains an important clinical problem in extracapsular resection of giant liver hemangiomas (GLHs), especially for those involving the proximal hepatic veins and/or inferior vena cava. Between July 2004 and March 2012, 87 patients with a complex GLH scheduled for surgical treatment were included in this study. All patients were underwent vascular preparation (Step 1), advanced hepatic artery clamping (Step 2), and stepwise vascular occlusion (Step 3). Intraoperative blood loss, blood transfusion volume, degree of ischemia-reperfusion injury, and postoperative complications were recorded. No patients required urgent vascular preparation to manage intraoperative bleeding. In total, 87, 64, and 21 patients had portal triad (PT), infrahepatic inferior vena cava (IVC), and suprahepatic IVC preparation; and 17, 43, and 11 patients had PT, PT and suprahepatic IVC, and all three (PT, infra-, and suprahepatic IVC) occlusions. The PT, infrahepatic IVC, and SIVC occlusion times were 12.1 ± 3.7 minutes, 7.9 ± 2.4 minutes, and 3.2 ± 1.4 minutes, respectively. Mean blood loss was 291.9 ± 124.5 mL, and only four patients received blood transfusions. No patients had life-threatening complications or died (Clavien-Dindo Grade 4, 5). Compared with paralleled studies, this technique has an advantage to decrease the blood loss in less liver ischemia time. For complex GLH resections, the described step-by-step vascular control technique was efficacious and feasible for controlling intraoperative bleeding.

Oval cell response is attenuated by depletion of liver resident macrophages in the 2-AAF/partial hepatectomy rat

BACKGROUND/AIMS

Macrophages are known to play an important role in hepatocyte mediated liver regeneration by secreting inflammatory mediators. However, there is little information available on the role of resident macrophages in oval cell mediated liver regeneration. In the present study we aimed to investigate the role of macrophages in oval cell expansion induced by 2-acetylaminofluorene/partial hepatectomy (2-AAF/PH) in rats.

METHODOLOGY/PRINCIPAL FINDINGS

We depleted macrophages in the liver of 2-AAF/PH treated rats by injecting liposome encapsulated clodronate 48 hours before PH. Regeneration of remnant liver mass, as well as proliferation and differentiation of oval cells were measured. We found that macrophage-depleted rats suffered higher mortality and liver transaminase levels. We also showed that depletion of macrophages yielded a significant decrease of EPCAM and PCK positive oval cells in immunohistochemical stained liver sections 9 days after PH. Meanwhile, oval cell differentiation was also attenuated as a result of macrophage depletion, as large foci of small basophilic hepatocytes were observed by day 9 following hepatectomy in control rats whereas they were almost absent in macrophage depleted rats. Accordingly, real-time polymerase chain reaction analysis showed lower expression of albumin mRNA in macrophage depleted livers. Then we assessed whether macrophage depletion may affect hepatic production of stimulating cytokines for liver regeneration. We showed that macrophage-depletion significantly inhibited hepatic expression of tumor necrosis factor-α and interleukin-6, along with a lack of signal transducer and activator of transcription 3 phosphorylation during the early period following hepatectomy.

CONCLUSIONS

These data indicate that macrophages play an important role in oval cell mediated liver regeneration in the 2-AAF/PH model.

Hepatic oval cell lines generate hepatocellular carcinoma following transfection with HBx gene and treatment with aflatoxin B1 in vivo

Hepatic oval cells (HOC) are considered to be the stem cells of the liver and have been linked to the development of hepatic malignancies. Studies have demonstrated that chronic hepatitis B virus (HBV) infection and dietary aflatoxin B1 (AFB1) exposure are among the most important risk factors for the development of hepatocellular carcinoma (HCC). However, little research has been done to evaluate the role of oval cells in these two environmental factors on hepatocarcinogenesis. In this study, partial transformation of rat HOC (LE/6) were accomplished by transfected HBV x gene (HBx), and then transfected cells were implanted both intra-hepatically and subcutaneously into nude mice treated with AFB1 in vivo. We found the oval cells produced tumors (4/24 of the animals) in liver following transfection with HBx gene and treatment with AFB1. These intrahepatic tumors included HCC cells (immunopositive for HepParl, ALB, CK8 and AFP) and mesenchymal cells (immunopositive for Vimentin and SMA). Whereas mesenchymal tumors were observed at the subcutaneous tissue with a similar rate in all controls treated with cell lines (10/24 in HBx-oval cells/AFB1 group, 8/20 in HBx-oval cells/non-AFB1 group, 10/20 in non-HBx/AFB1 group; 9/20 in non-HBx/non-AFB1 group). Conversely, none of the controls developed intrahepatic tumors. These results provide an evidence that oval cells have the capacity to generate HCC through the combined effects of the HBx and AFB1 in the liver microenvironment.

The epithelial-mesenchymal transition promotes transdifferentiation of subcutaneously implanted hepatic oval cells into mesenchymal tumor tissue

Hepatic oval cells are thought to represent facultative hepatic epithelial stem cells in liver in which damage inhibits hepatocyte proliferation and liver regeneration. The LE/6 hepatic stem cell line was derived from the liver of male Sprague-Dawley rats fed a choline-deficient diet containing 0.1% ethionine. They are histochemically characterized by their expression of hepatocytic (hepPar1), cholangiocytic cytokeratin (CK19), hepatic progenitor cell (OV-6), and hematopoietic stem cell (c-kit) markers. In this study, we transplanted LE/6 cells by subcutaneous injection into adult female nude mice, and examined their engraftment and differentiation potential in the subcutaneous microenvironment in vivo. Our results demonstrated that following subcutaneous transplantation, differentiation of LE/6 cells into mesenchymal tumor tissue (MTT) was associated with reduced E-cadherin expression, upregulation of E-cadherin repressor molecules (Snail proteins), and increased expression of vimentin and N-cadherin, all of these events are characteristic of the epithelial-mesenchymal transition (EMT).

[Differentiation of hepatic oval cell into mature hepatocyte induced by hepatic stellate cells]

OBJECTIVE

To investigate the role of hepatic stellate cells in the differentiation of hepatic oval cells into adult hepatocyte.

METHODS

The oval cell were cocultured with primary hepatic stellate cells (HSC) in the same well (M-coculture) or separately cultured with HSC by millIcell (S-coculture). Oval cells were cultured alone as control; the expression of adult hepatocyte marker HNF-4alpha, albumin, and oval cell marker AFP, CK-19 in each group were detected by real-time PCR and western-blot. Phenotype changes were observed by transmission electron microscope (TEM); PAS staining was used to detect the quantity of glycogen granule in oval cell. Albumin level in supernatant was detected using ELISA kit.

RESULT

(1) The relative level of HNF-4alpha and albumin mRNA expression compared with pre-coculture: M-coculture: HNF-4a: 1.9+/-0.2, 10.7+/-1.2, 12.0+/-1.3; albumin: 5.7+/-1.6, 110.7+/-13.7, 173.6+/-22.3. S-coculture: 1.4+/-0.1, 3.2+/-0.6, 8.9+/-1.4 times; albumin: 2.9+/-1.4, 22.3+/-8.5, 96.3+/-16.3. The relative level of HNF-4a and albumin mRNA expression in coculture group (M- and S-coculture) were higher than control group (LSD-t: 32.98, 10.08, 13.38, 7.96; P less than 0.01); and a higher level of HNF-4a and albumin was found in M-coculture group compared to S-coculture group (LSD-t: 32.98, 25.65; P less than 0.01). The relative level of AFP and CK-19 mRNA expression compared with pre-coculture: M-coculture: 1.1+/-0.2, 0.2+/-0.0, 0.0+/-0.0; S-coculture group: AFP: 1.0+/-0.2, 0.2+/-0.1, 0.1+/-0.0; CK-19: 0.6+/-0.1, 0.1+/-0.0, 0.0+/-0.0; control group: AFP: 1.0+/-0.1, 1.0+/-0.1, 1.1+/-0.1, CK-19: 1.0+/-0.1, 1.1+/-0.1, 1.0+/-0.1. The relative level of AFP and CK-19 mRNA expression in coculture group (M- and S-coculture) were lower than that in control group (LSD-t: 37.99, 34.50, 13.59, 22.46; P less than 0.01). (2) The albumin secretion was detected in M-coculture: 14 day: (15.30+/-0.09) ng/ml, 21: (20.98+/-0.12) ng/ml; S-coculture: 14 day: (11.41+/-0.13) ng/ml, 21 day:(15.12+/-0.17) ng/ml. (3) It showed more organelles such as endoplasmic reticulum, mitochondrion and Golgi apparatus in oval cells cocultured with HSC. And cholangiole-like structure appeared between oval cells cocultured with HSC. (4) PAS staining showed glycogen granules could be observed in coculture groups.

CONCLUSION

HSC can induce differentiation of oval cell into mature hepatocyte.

[Preliminary study on cardiac allograft rejection in mice by Extractum trametes robiniophila murr]

OBJECTIVE

To study the effect of Extractum trametes robiniophila murr on cardiac allograft rejection in mice.

METHODS

All abdominal heterotopic heart transplantation models were divided into three groups as follows: (A) Extractum trametes robiniophila murr group. (B) Rejection group. (C) Isograft group. In each group, mean survival times (MST) of transplanted hearts and their pathologic histological changes at postoperative fifth day were observed. With fluoroimmunoassay, granzyme B and CD8(+) expressions were examined.

RESULTS

The MST of heart allografts in group A were (6.38 +/- 0.69) d, significantly shorter than that of group B [(8.31 +/- 0.59) d] (P < 0.01). In group A, acute rejection was present in advance; transplanted hearts were seriously damaged into acute rejection pathological grade 3, and CD8(+) T lymphocytes infiltrated diffusely and the expression of granzyme B increased significantly as compared with other groups.

CONCLUSIONS

Exclusive application of Extractum trametes robiniophila murr can promote the acute rejection of graft in early phase of postoperation, and the mechanism may be the promoted proliferation and infiltration of CD8(+) T lymphocytes and the increased expression of granzyme B.

Hyaluronic acid fragments evoke Kupffer cells via TLR4 signaling pathway

Kupffer cells, expressing toll-like receptor 4 (TLR4), play a central role in hepatic ischemia/reperfusion (I/R) injury. Hyaluronic acid (HA) fragments, degradative products of high-molecular-weight HA (HMW-HA), acquire the ability to activate immune cells under inflammatory conditions. Here we investigated whether HA fragments could activate Kupffer cells and analyzed the underlying mechanism. Kupffer cells were isolated from wild-type mice (WT, C3H/HeN) and TLR4 mutant mice (C3H/HeJ) and HA fragments were produced by the methods of enzyme digestion and chromatography. Then Kupffer cells were stimulated by HA fragments or other control stimuli. The activation of Kupffer cells was estimated as the release of pro-inflammatory cytokines. The activation of p38 MAPK pathway of Kupffer cells was checked and blocking experiments were done as well. The results indicated that HA fragments acquired the ability to activate Kupffer cells in vitro, which was TLR4 dependent and not due to contamination of lipopolysaccharide. Experiments of p38 MAPK kinase inhibition by SB-203580 verified p38 MAPK was required in HA fragments induced Kupffer cells activation. This suggests that HA fragments, degradative products of one of the major glycosaminoglycans of the extracellular matrix, play critical roles in Kupffer cell activation mediated by TLR4 signaling pathway, which is, at least partially, dependent on p38 MAPK activation.

Stability of a biological tissue fixed with a naturally occurring crosslinking agent (genipin)

The study was undertaken to investigate the stability of a biological tissue fixed with a naturally occurring crosslinking agent (genipin) at distinct elapsed storage durations. The glutaraldehyde-fixed counterpart was used as a control. Porcine pericardia procured from a slaughterhouse were used as raw materials. After fixation, the fixed tissues were sterilized in a graded series of ethanol solutions and thoroughly rinsed in phosphate buffered saline for 1 day, and then stored in a jar containing sterilized water. The samples were taken out and tested for their stability during the durations of 1day through 6 months after storage. The stability of each study group was tested by measuring its tensile strength, free-amino-group content, and denaturation temperature. Additionally, the cytotoxicity of each test sample and its corresponding storage solution were investigated in vitro using 3T3 fibroblasts. The results were examined using a microscope and 3-(4,5-dimethylthiazol-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. It was found that the stability of the genipin-fixed tissue during storage was superior to its glutaraldehyde-fixed counterpart. The differences in stability between the genipin- and glutaraldehyde-fixed tissues during storage may be caused by their differences in crosslinking structure. There was no apparent cytotoxicity for both the genipin-fixed tissue and its corresponding storage solution throughout the entire course of the study, whereas significant cytotoxicity was observed for both the glutaraldehyde-fixed tissue and its storage solution. However, the cytotoxicity of the glutaraldehyde-fixed tissue decreased with increasing elapsed storage duration, whereas that of its corresponding storage solution increased. This suggested that the toxic residues remaining in the glutaraldehyde-fixed tissue leached out slowly into its corresponding storage solution during the course of storage.