Three isoforms of exosomal circPTGR1 promote hepatocellular carcinoma metastasis via the miR449a-MET pathway

BACKGROUND

The role of exosomal circular RNAs (circRNAs) in Hepatocellular carcinoma (HCC) cells with high metastatic potential has been little studied.

METHODS

Exosomal circRNA from cells with non-metastatic (HepG2), low metastatic (97L), and high metastatic (LM3) potential were sequencing. Metastatic-related circRNAs in serum from HCC patients were measured and their association with clinical prognosis was evaluated. Furthermore, candidate functional circRNAs in LM3-derived exosomes was assessed.

FINDINGS

LM3 exosomes enhanced the cell migration and invasion potential of HepG2 and 97 L cells. CircPTGR1, a circRNA with three isoforms, was specifically expressed in exosomes from 97 L and LM3 cells, upregulated in serum exosomes from HCC patients and was associated with the clinical stage and prognosis. Knockdown of circPTGR1 expression suppressed the migration and invasion of HepG2 and 97L cells induced by co-culturing with LM3 exosomes. Bioinformatics, co-expression analysis, and a luciferase assay indicated that circPTGR1 competed with MET to target miR449a.

INTERPRETATION

Higher metastatic HCC cells can confer this potential on those with lower or no metastatic potential via exosomes with circPTGR1, resulting in increased migratory and invasive abilities in those cells. FUND: National Natural Science Foundation of China (No. 81470870, 81670601, 81570593), Guangdong Natural Science Foundation (No. 2015A030312013, 2015A030313038), Sci-tech Research Development Program of Guangdong Province (2014B020228003), Sci-tech Research Development Program of Guangzhou City (No. 201508020262, 201400000001-3, 201604020001, 201607010024), Innovative Funds for Small and Medium-Sized Enterprises of Guangdong Province (2016A010119103), Pearl River S&T Nova Program of Guangzhou (201710010178), and National 13th Five-Year Science and Technology Plan Major Projects of China (No. 2017ZX10203205-006-001).

A scoring model based on neutrophil to lymphocyte ratio predicts recurrence of HBV-associated hepatocellular carcinoma after liver transplantation

BACKGROUND

Neutrophil to lymphocyte ratio (NLR) has been proposed to predict prognosis of hepatocellular carcinoma (HCC). However, the cut-off values are empirical. We determined the optimal cut-off value to predict HCC recurrence after liver transplantation (LT) and further established a scoring model based on NLR.

METHODOLOGY/PRINCIPAL FINDINGS

We analyzed the outcome of 101 HBV-associated HCC patients undergoing LT. Preoperative risk factors for tumor recurrence were evaluated by univariate analysis. By using ROC analysis, NLR≥3 was considered elevated. The disease-free survival (DFS) and overall survival (OS) for patients with high NLR was significantly worse than that for patients with normal NLR (the 5-year DFS and OS of 28.5% and 19.5% vs. 64.9% and 61.8%, respectively; P<0.001). Univariate analysis revealed that tumor size >5 cm, tumor number >3, macrovascular invasion, AFP≥400 µg/L, NLR≥3, and HBV-DNA level >5 log10 copies/mL were preoperative predictors of DFS. Cox regression analysis showed macrovascular invasion, tumor number, and high NLR were independent prognostic factors. We then established a preoperative prognostic score based on multivariate analysis. Each factor was given a score of 1. Area under the ROC curve of the score was 0.781. All nine patients with score 3 developed recurrence within 6 months after LT. Of 71 patients without vascular invasion, three patients with both tumor number >3 and NLR≥3 developed recurrence within 14 months after LT while the 5-year DFS and OS for patients with a score of 0 or 1 were 68.1% and 62.8%, respectively.

CONCLUSIONS/SIGNIFICANCE

Preoperative elevated NLR significantly increases the risk of recurrence in patients underwent LT for HCC. Patients with both NLR≥3 and tumor number >3 are not a good indication for LT. Our score model may aid in the selection of patients that would most benefit from transplantation for HCC.

Rapamycin-treated mature dendritic cells have a unique cytokine secretion profile and impaired allostimulatory capacity

Rapamycin (RAPA, sirolimus) is a recently introduced immunosuppressive agent. Its effect on the differentiation and antigen uptake of immature dendritic cells (iDCs) has been studied. However, whether it can also modulate the function of mature DCs (mDCs) is unknown. We investigated the effects of RAPA on rat bone marrow-derived DCs at different stages of maturation. RAPA affected maturation, increased apoptosis and reduced lipopolysaccharide (LPS)-induced IL-12 and IL-10 production in iDCs. However, mDCs were resistant to RAPA-induced apoptosis. RAPA-mDCs produced significantly less IL-10 and TNF-alpha when compared with mature DCs but similar amounts of IL-12. RAPA did not affect constitutive NF-kappaB activity, but inhibited allostimulatory activity in mature DCs. In conclusion, mDCs treated with RAPA are reprogrammed to produce a unique cytokine secretion profile and exhibit low allostimulatory capacity, which may play an important role in rapamycin-based immunomodulation.

Pretransplant Elevated Plasma Fibrinogen Level is a Novel Prognostic Predictor for Hepatocellular Carcinoma Recurrence and Patient Survival Following Liver Transplantation

BACKGROUND

Elevated plasma fibrinogen is associated with tumour progression and poor outcomes in several cancers. The present study investigated the prognostic value of preoperative fibrinogen in hepatocellular carcinoma (HCC) patients after liver transplantation (LT).

MATERIAL AND METHODS

We analyzed the preoperative plasma fibrinogen levels of 41 patients who underwent LT for HCC. The cut-off value for elevated level of fibrinogen was determined by using a receiver operating characteristic (ROC) curve analysis. Cox regression analysis was performed to analyze the relationship between elevated fibrinogen level and HCC recurrence. The disease-free survival (DFS) and overall survival (OS) rate after transplantation were calculated by Kaplan-Meier method and compared by log-rank test.

RESULTS

The fibrinogen levels were significantly higher in patients with tumor recurrence (3.31±0.98 g/L) compared with those in patients without recurrence (2.39±0.89 g/L) (P<0.01). A cut-off value for elevated fibrinogen level of 2.675 g/L was defined. Cox regression analysis showed that the relative risk for tumor recurrence increased by 6.871 times for patients with elevated fibrinogen. Eleven patients in the elevated fibrinogen group (21 cases) developed recurrence, while only 2 in the normal fibrinogen group (20 cases) developed recurrence. There were significant differences in DFS and OS between the elevated fibrinogen group and normal fibrinogen group (5-year DFS and OS of 44.0% and 42.9% vs. 89.2% and 80.0%, respectively, P<0.05). Vascular invasion and fibrinogen level ≥2.675 g/L were the independent prognostic predictors of tumor recurrence and poor outcome.

CONCLUSIONS

Pretransplant elevated fibrinogen levels are associated with tumor recurrence and poor prognosis in hepatocellular carcinoma patients after liver transplantation.

Rapamycin combined with donor immature dendritic cells promotes liver allograft survival in association with CD4(+) CD25(+) Foxp3(+) regulatory T cell expansion

AIM

  To determine whether donor immature dendritic cells (imDCs) combined with a short postoperative course of rapamycin (Rapa) has the ability to expand the CD4(+) CD25(+) Foxp3(+) regulatory T (Treg) cells and prolong liver allograft survival.

METHODS

  Orthotopic liver transplantation (OLT) was performed from Lewis rats to Brown Norway recipients. Three days before transplantation, animals were injected intravenously with 2 × 10(6) donor bone marrow-derived imDCs. Recipient rats (the combined treated group) also received Rapa for 7 d after liver transplantation. Additional groups received either imDCs alone, Rapa alone, or saline alone. Every six recipients from each group were killed at 14 days, 28 days after OLT. The changes of CD4(+) CD25(+) Foxp3(+) Treg cells in peripheral blood and spleen, histological changes of liver grafts, and serum cytokine levels were investigated. The other six recipients were left in each group to observe the animal survival.

RESULTS

  Donor imDCs followed by a short postoperative course of Rapa induced long-term allograft survival. The percentage of CD4(+) CD25(+) Foxp3(+) Treg cells in CD4(+) T cells in the combination treatment group were significantly higher compared with the acute rejection group. Moreover, within the CD4(+) CD25(+) T cell population the combination treatment recipients maintained a higher incidence of Foxp3(+) T cells compared with the other groups. Despite the lower serum levels of interleukin (IL)-2, IL-12, and interferon-γ in the combined treated group, the cytokine levels in the combined treated group at 7 days after OLT was nearly twice that at 3 days after OLT but decreased significantly compared with the other groups at 28 days after OLT. Serum IL-10 level in the combined treated group was higher than the other groups.

CONCLUSIONS

  A single imDC infusion followed by a short postoperative course of Rapa prolongs liver allograft survival and enhances the expansion of Treg cells. This optimal protocol may be a promising administration protocol for the peritransplant tolerance induction.

Rapamycin combined with allogenic immature dendritic cells selectively expands CD4+CD25+Foxp3+ regulatory T cells in rats

BACKGROUND

Dendritic cells (DCs) can initiate the expansion of regulatory T cells (Tregs), which play an indispensable role in inducing transplantation tolerance. Some studies have investigated the effect of the immunosuppressant rapamycin (Rapa) on Tregs in vitro. However, the in vivo effect of Rapa combined with immature DCs (iDCs) on Tregs is unknown. This study was undertaken to determine whether allogenic iDCs combined with a short course of Rapa have the ability to selectively expand the CD4+CD25+Foxp3+ Tregs in a rat model.

METHODS

Brown Norway rats were injected intravenously with 2X10(6) Lewis iDCs followed by 1 mg/kg per day Rapa intraperitoneally for 7 consecutive days. On day 8, the levels of CD4+CD25+Foxp3+ Treg cells in peripheral blood and spleen cells were analyzed by flow cytometry. IL-2, IL-4, TGF-beta1, and IFN-gamma levels in serum were assessed by ELISA. The experimental animals were divided into four groups: control, Rapa-treated, iDC-treated, and combination-treated.

RESULTS

CD4+CD25+Foxp3+ Tregs comprised 7%-8% of CD4+ T cells in control rats. Rapa combined with iDCs enhanced this percentage in the peripheral blood and spleen. However, the levels of Tregs did not significantly change after treatment with Rapa or iDCs alone. The levels of CD4+CD25-Foxp3+ T cells and CD4+CD25+Foxp3- T cells in CD4+ T cells did not significantly change in the combined group. The TGF-beta1 level in serum from the combined group increased significantly compared with the other groups.

CONCLUSIONS

A significantly higher percentage of CD4+ CD25+ Foxp3+ Tregs was found in rats treated with allogenic iDCs and a short course of Rapa, along with an increase in the TGF-beta1 level in serum. This improved protocol may be a promising therapeutic strategy to increase Tregs, which are beneficial to the induction of peritransplant tolerance.

Elevated blood eosinophil count is a valuable biomarker for predicting late acute cellular rejection after liver transplantation

BACKGROUND

Recent studies have indicated the value of increased blood eosinophil counts for the diagnosis of acute cellular rejection (ACR) after orthotopic liver transplantation (OLT). However, the relationship between eosinophil count and late ACR at more than 6 months after OLT is still unclear.

METHODS

We sought to retrospectively analyzed the ACR predictive value of eosinophil counts. In the day before or the day of biopsy among 40 biopsies performed on 37 patients beyond 6 months after OLT.

RESULTS

Relative eosinophil count was significantly higher in the ACR (n = 24) than the non-ACR cohort, albeit with no significant difference in absolute eosinophil count. Receiver operating characteristic (ROC) analysis showed an absolute eosinophil count of 0.145 × 10(9)/L and a relative eosinophil count of 2.3% to show the highest Youden index with area under the ROC curves of 0.746 and 0.813, respectively. When absolute eosinophil count ≥ 0.145 × 10(9)/L or relative eosinophil count ≥ 2.3% was defined to be elevated, the sensitivity and specificity to predict ACR were 45.8% and 87.5%, and 75% and 87.5%, respectively. When the absolute eosinophil count ≥ 0.285 × 10(9)/L or relative eosinophil count ≥ 3% was defined as elevated, the sensitivity and specificity were 25% and 100%, and 50% and 100%, respectively. All patients with an absolute eosinophil count ≥ 0.285 × 10(9)/L showed a relative eosinophil count ≥ 3%.

CONCLUSIONS

Elevated blood eosinophil count was a valuable biomarker to predict late ACR after OLT.

Rapamycin inhibits activator protein-1 but not nuclear factor-kappaB activity of mature bone marrow-derived dendritic cells

Rapamycin (Rapa), a recently introduced immunosuppressive drug, appears to be effective in preventing acute allograft rejection episodes. Its effects on differentiation and maturation of dendritic cells (DCs) have been studied. In this report, we evaluated the effects of Rapa on the intracellular signal transduction pathways in mature DCs. The results showed that Rapa did not depress p65, p50, or IkappaBalpha expression. However, it dramatically reduced activator protein-1 activation. The fact that Rapa exerts a specific effect on activator protein-1 activity in mature DCs may contribute to its unique actions to prevent allograft rejection and induce immune tolerance.

[Preoperative neutrophil-lymphocyte ratio as a prognostic predictor after liver transplantation for hepatocellular carcinoma]

OBJECTIVE

To analyze the negative impact of preoperative neutrophil-lymphocyte ratio (NLR) on the tumor recurrence of hepatocellular carcinoma (HCC) after orthotopic liver transplantation.

METHODS

The clinical data of HBV (hepatitis B virus)-associated HCC patients undergoing liver transplantation were retrospectively analyzed. Their clinical and pathological risk factors for tumor-free survival were evaluated by univariate analysis. The analysis of Cox multiple regression was performed to determine the parameters of predicting the HCC recurrence. NLR ≥ 2.5 was considered to be elevated.

RESULTS

A total of 76 patients were identified. Among them, 37 had an elevated NLR. The 1, 3 and 5-year tumor-free survival rates were 69.2%, 52.7% and 50.9% respectively. The disease-free survival for patients with high NLR was significantly worse than that for those with normal NLR (1, 3, and 5 year survivals at 56.3%, 37.6% and 37.6% vs 81.1%, 66.9% and 63.3% respectively; P = 0.011). Univariate analysis of factors revealed that tumor size > 5 cm, tumor number > 3, vascular invasion, serum α-fetoprotein level ≥ 400 µg/L and NLR ≥ 2.5 were preoperative predictors of disease-free survival. Cox regression analysis showed that the presence of vascular invasion, tumor number > 3 and NLR ≥ 2.5 were independent prognostic factors of worse disease-free survival.

CONCLUSION

An elevated NLR significantly increases the risk for tumor recurrence in HCC patients undergoing liver transplantation.

Nrf2 deficiency causes hepatocyte dedifferentiation and reduced albumin production in an experimental extrahepatic cholestasis model

The transcription factor Nrf2 modulates the initiation and progression of a number of diseases including liver disorders. We evaluated whether Nrf2 mediates hepatic adaptive responses to cholestasis. Wild-type and Nrf2-null mice were subjected to bile duct ligation (BDL) or a sham operation. As cholestasis progressed to day 15 post-BDL, hepatocytes in the wild-type mice exhibited a tendency to dedifferentiate, indicated by the very weak expression of hepatic progenitor markers: CD133 and tumor necrosis factor-like weak induced apoptosis receptor (Fn14). During the same period, Nrf2 deficiency augmented this tendency, manifested by higher CD133 expression, earlier, stronger, and continuous induction of Fn14 expression, and markedly reduced albumin production. Remarkably, as cholestasis advanced to the late stage (40 days after BDL), hepatocytes in the wild-type mice exhibited a Fn14+ phenotype and strikingly upregulated the expression of deleted in malignant brain tumor 1 (DMBT1), a protein essential for epithelial differentiation during development. In contrast, at this stage, hepatocytes in the Nrf2-null mice entirely inhibited the upregulation of DMBT1 expression, displayed a strong CD133+/Fn14+ phenotype indicative of severe dedifferentiation, and persistently reduced albumin production. We revealed that Nrf2 maintains hepatocytes in the differentiated state potentially via the increased activity of the Nrf2/DMBT1 pathway during cholestasis.