PPARγ activation reduces ischemia/reperfusion-induced metastasis in a murine model of hepatocellular carcinoma

In vivo study revealed pro-tumorigenic effect of CMTM3 in hepatocellular carcinoma involving the regulation of peroxisome proliferator-activated receptor gamma (PPARγ)

PURPOSE

To clarify the ambiguity of the function of CMTM3 in the development of hepatocellular carcinoma (HCC) and explore its molecular mechanism.

METHODS

The Cmtm3-KO C57BL/6 mouse strain was established using CRISPR-Cas9. Acute liver damage and HCC models were induced by peritoneal injection of 100 or 25 mg/kg.BW N-Nitrosodiethylamine (DEN) to male mice. Liver function and histology were evaluated by blood serum levels of AST and ALT, and HE staining. Gene and protein expression in liver tissues was investigated by RNA-seq, RT-qPCR, Western blotting, immunohistochemistry, and immunofluorescence. Protein-protein interactions were studied by STRING and topological measures. The mRNA expression of CMTM3 and PPARs and patient survival were analyzed using the UALCAN database.

RESULTS

Global knockout of Cmtm3 in KO mice was successfully confirmed. Cmtm3 knockout alleviated DEN-induced acute damage to liver histological integrity and liver function, reduced DNA damage and apoptosis, and also caused a significantly reduced number (WT: 8.7 ± 5.5 vs. KO: 2.7 ± 3.1, P = 0.0394) and total size of tumors (WT: 130.9 ± 181.8 mm² vs. KO: 9.3 ± 11.5 mm², P = 0.026) in the liver. Mechanistically, Cmtm3 knockout resulted in reduced expression and inactivation of Pparγ and its downstream lipid metabolism genes (e.g. Adipoq) upon DEN intoxication. CMTM3 and PPARγ were both overexpressed in HCC, and higher levels of both genes were associated with worse overall survival of HCC patients.

CONCLUSION

This study clarified the pro-tumorigenesis role of CMTM3 in HCC in vivo, possibly through the upregulation of PPARγ and activation of the PPAR pathway.

PPARγ Mediates Protective Effect against Hepatic Ischemia/Reperfusion Injury via NF-κB Pathway

BACKGROUND

Hepatic ischemia/reperfusion injury (HIRI) is an unavoidable complication in liver surgery, however its pathological process is still unclear. Therefore, in this study, the role and mechanism of peroxisome proliferator-activated receptor gamma (PPARγ) was investigated in HIRI.

MATERIALS AND METHODS

We constructed mice models with HIRI and L02 cell models insulted hypoxia/re-oxygenation (H/R). PPARγ agonist rosiglitazone was administered prior to HIRI in mice and PPARγ-siRNA was to H/R treatment in L02 cells. Liver injury was measured by serum ALT, AST and LDH levels and performing H&E staining; the inflammatory injury was reflected by inflammatory markers IL-1β, IL-6 and TNF-α, which were assayed by Real-time PCR and Western blotting, MPO activity was determined using commercial kits; oxidative stress injury was evaluated by iNOS, MDA, SOD and GSH-PX levels; apoptosis was detected by cleaved-Caspase-3, TUNEL staining and flow cytometry; NF-κB signaling activation was reflected by phosphorylation of IκBα (p-IκBα) and nuclear translocation of NF-κB p65.

RESULTS

The level of PPARγ expression was obviously down-regulated both in mice liver subjected to IRI and in L02 cells to H/R. Overexpression of PPARγ presented protective effect on HIRI by reducing serum levels of aminotransferase and hepatic necrosis, inhibiting inflammation and apoptosis and alleviating oxidative stress in vivo. But PPARγ-siRNA aggravate H/R insult by promoting inflammation and apoptosis in vitro. Mechanistically, the NF-κB pathway activity was increased with PPARγ down-regulation by PPARγ-siRNA. Importantly, inhibition of NF-κB signaling abolished PPARγ knockdown-mediated hepatic injury.

CONCLUSIONS

PPARγ present protective effects on HIRI by attenuating liver injury, inflammatory response, oxidative stress and apoptosis in vivo and in vitro, and its mechanism may be related to down-regulation of NF-κB signaling.

One Shoot, Two Birds: Alleviating Inflammation Caused by Ischemia/Reperfusion Injury to Reduce the Recurrence of Hepatocellular Carcinoma

Inflammation is crucial to tumorigenesis and the development of metastasis. Hepatic ischemia/reperfusion injury (IRI) is an unresolved problem in liver resection and transplantation which often establishes and remodels the inflammatory microenvironment in liver. More and more experimental and clinical evidence unmasks the role of hepatic IRI and associated inflammation in promoting the recurrence of hepatocellular carcinoma (HCC). Meanwhile, approaches aimed at alleviating hepatic IRI, such as machine perfusion, regulating the gut-liver axis, and targeting key inflammatory components, have been proved to prevent HCC recurrence. This review article highlights the underlying mechanisms and promising therapeutic strategies to reduce tumor recurrence through alleviating inflammation induced by hepatic IRI.

Rosuvastatin alleviated the liver ischemia reperfusion injury by activating the expression of peroxisome proliferator-activated receptor gamma (PPARγ)

Liver ischemia and reperfusion could cause serious damage to liver tissues. Abnormal liver function could induce serious damage and threaten human health. Evidence emerged to suggest that rosuvastatin could relieve cerebral ischemia-reperfusion injury and alleviate the disease related to vessels by activating the expression of PPARγ. However, whether rosuvastatin could relieve the liver ischemia reperfusion injury by enhancing the expression of PPARγ is unclear. For the strictness of experimental findings, we established both the rat models and the cell model of liver ischemia reperfusion injury by respectively treating rats and cells with rosuvastatin. PPARγ inhibitor was also used for the stimulation of these cells and rats. Reactive oxygen species (ROS) levels, apoptosis and related protein levels were determined with ROS staining, ROS staining and western blotting for the detection of injury induced by oxygen-glucose deprivation and re-oxygenation (OGD/R). Pretreatment of rosuvastatin promoted the expression of PPARγ in liver tissues and MIHA cells. It also inhibited the ischemia reperfusion and OGD/R induced production of ROS while promoted the release of SOD in liver tissues and MIHA cells. Furthermore, rosuvastatin also alleviated the ischemia reperfusion -induced apoptosis of liver tissues and OGD/R-induced MIHA cells apoptosis. However, application of PPARγ inhibitor abolished the restorative effects of rosuvastatin on the apoptosis and oxidative stress on liver tissues and MIHA cells. Rosuvastatin prevented the liver ischemia reperfusion injury of rats by activating PPARγ.

The herbal agent plantamajoside, exerts a potential inhibitory effect on the development of hepatocellular carcinoma

Plantamajoside (PMS), a major component of Plantago asiatica L, has several pharmacological properties, including anti-proliferative, anti-inflammatory and anti-tumor effects. However, the effects of PMS on hepatocellular carcinoma (HCC) have yet to be determined. The aim of the present study was to investigate the effects of PMS on HCC and elucidate the underlying mechanism. All assays were conducted using 5 groups, namely control, sorafenib, and PMS 100, 50, and 25 µg/ml groups. Cell proliferation was determined by the MTT assay. Cell migration was evaluated with the wound healing and Transwell assays, respectively. Cell apoptosis and cell cycle distribution were evaluated via flow cytometry. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis and western blotting were used to further investigate the mechanism of action of PMS. Sorafenib and PMS both significantly attenuated the proliferation and migration of HCC cells, and markedly promoted cell apoptosis. PMS induced cell cycle arrest in the G0/G1 phase. The efficacy of PMS increased in a dose-dependent manner. Further study evaluated the expression of peroxisome proliferator-activated receptor (PPARγ), nuclear factor (NF)-κB and cyclooxygenase (Cox-2) using RT-qPCR analysis and western blotting. The results demonstrated that PMS promoted the expression of PPARγ and suppressed the expression of NF-κB and Cox-2. In conclusion, PMS was shown to affect cell proliferation, migration, apoptosis and cell cycle distribution. Furthermore, PMS promoted the expression of PPARγ and inhibited the expression of NF-κB and Cox-2, which may be the mechanism underlying its biological effects. Based on the results of the present study, PMS appears to be a promising agent for HCC therapy.

Efficacy of traditional herbal medicine versus transcatheter arterial chemoembolization in postsurgical patients with hepatocellular carcinoma: A retrospective study

BACKGROUND

Recurrence is a major obstacle to improve the prognosis of hepatocellular carcinoma (HCC) patients. Transcatheter arterial chemoembolization (TACE) has been routinely used as an adjuvant therapy in treating HCC, but efficacy of TACE in preventing the recurrence of HCC remains unsatisfactory. This study aimed to compare the efficacy of a traditional herbal medicine (THM) therapy and TACE in preventing tumor recurrence and improving survival in postsurgical patients with HCC.

MATERIALS AND METHODS

A total of 1506 HCC patients were enrolled from January 2008 to June 2017, including 262 patients who received THM therapy and 1244 patients who were treated with TACE. All patients were followed up until the occurrence of outcome event or June 30th, 2019. The recurrence-free survival (RFS) and overall survival (OS) were calculated by the Kaplan-Meier method, and the differences of RFS and OS between THM group and TACE group were analyzed by the log-rank test. Factors affecting the RFS or OS among these patients were assessed by the Cox proportional hazard regression model. A nomogram was built with the factors based on the Cox regression analysis to predict the prognosis.

RESULTS

The 1-, 3-, and 5-year RFS were 91.0%, 68.3%, and 49.7%, respectively, in the THM group and 79.4%, 38.6%, and 19.3%, respectively, in the TACE group. The RFS in the THM group was significantly higher than that of the TACE group (P = 6.2 × 10^-11). The 1-, 3-, and 5-year OS were significantly improved in the THM group as compared to those in the TACE group (94.3%, 65.2%, and 41.4% vs. 82.7%, 46.0%, and 25.4%, P = 2.2 × 10^-11). Multivariate analysis revealed that serum AFP level ≥400 ng/mL, HBV DNA load ≥500 copies/mL, TNM stage III-IV, tumor diameter ≥5 cm, presence of MVI, and multiple tumor nodules were independent risk factors for RFS, while complete tumor encapsulation and THM therapy were protective factors for RFS and OS. The nomogram demonstrated good accuracy in predicting RFS and OS, with the adjusted C-index of 0.748 and 0.796, respectively.

CONCLUSION

The efficacy of THM therapy was superior to that of TACE in preventing recurrence and improving survival for HCC patients after hepatectomy.

Ischemia reperfusion-induced metastasis is resistant to PPARγ agonist pioglitazone in a murine model of colon cancer

Ischemia reperfusion injury (IRI) during liver-metastasis resection for treatment of colon cancer may increase the risk of further metastasis. Peroxisome proliferator-activated receptor-γ (PPARγ) activation has been observed to exert a protective effect against IRI and IRI-induced metastasis of hepatocellular carcinoma. The present study aimed to investigate the effect of the PPARγ agonist pioglitazone on tumor metastasis and liver injury following IRI in a mouse model of colon cancer. Pioglitazone (30 mg/kg weight) was administered orally 1.5 h before and 2 h after the initiation of ischemia and was orally administrated daily to mice from day 0–21. SL4-cancer cells expressing red fluorescent protein (SL4-RFP) (1 × 10⁶) were injected into the spleen. Fifteen minutes after injection, the hepatoduodenal ligament was clamped with a vessel clip, and released 5 min later. Liver, blood and tumor samples were taken from mice in order to determine if inflammation was induced by IRI. The effect of pioglitazone on liver metastasis was assessed. Furthermore, the effect of pioglitazone to control the inflammatory response during IRI progression was examined. Liver metastasis along with MMP-9 activation and the production of inflammatory cytokines were resistant to pioglitazone. Our results indicate that liver metastasis and associated inflammation in mice were resistant to pioglitazone.

Effect of sevoflurane pretreatment in relieving liver ischemia/reperfusion-induced pulmonary and hepatic injury

Purpose

To investigate the effect of sevoflurane preconditioning on ischemia/reperfusion (I/R)-induced pulmonary/hepatic injury

Methods

Fifty-one Wistar rats were randomly grouped into sham, I/R, and sevoflurane groups. After reperfusion, the structural change of the lung was measured by Smith score, the wet and dry weights (W/D) were determined, malondialdehyde (MDA) myeloperoxidase (MPO) content was determined colorimetrically and by fluorescence, respectively, and matrix metalloprotein-9 (MMP-9) mRNA was quantified by RT-PCR. Biopsy and morphological analyses were performed on liver tissue, activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were determined, and tumor necrosis factor-alpha (TNF-α) level was determined.

Results

The sham group showed no changes in tissue structure. Structural lesions in the sevoflurane and I/R groups were mild and severe, respectively. Smith score, W/D, MDA, MPO, and MMP mRNA showed the same trend, and were increased in the I/R group and recovered in the sevoflurane group, compared with the sham group (both P<0.05). AST and ALT were significantly increased compared to the sham group (AST: 655±52.06 vs . 29±9.30 U/L; ALT: 693±75.56 vs . 37±6.71 U/L; P<0.05). In the sevoflurane group, AST and ALT levels were significantly decreased (464±47.71 and 516±78.84 U/L; P<0.001). TNF-α presented similar results.

Conclusion

The protection of lung and liver by sevoflurane may be mediated by inhibited leukocyte recruitment and MMP-9 secretion.

Use of Steatotic Grafts in Liver Transplantation: Current Status

In the field of liver transplantation, the demand for adequate allografts greatly exceeds the supply. Therefore, expanding the donor pool to match the growing demand is mandatory. The present review summarizes current knowledge of the pathophysiology of ischemia/reperfusion injury in steatotic grafts, together with recent pharmacological approaches aimed at maximizing the utilization of these livers for transplantation. We also describe the preclinical models currently available to understand the molecular mechanisms controlling graft viability in this specific type of donor, critically discussing the heterogeneity in animal models, surgical methodology, and therapeutic interventions. This lack of common approaches and interventions makes it difficult to establish the pathways involved and the relevance of isolated discoveries, as well as their transferability to clinical practice. Finally, we discuss how new therapeutic strategies developed from experimental studies are promising but that further studies are warranted to translate them to the bedside.

New insights into molecular mechanisms of rosiglitazone in monotherapy or combination therapy against cancers

Rosiglitazone (ROSI), a member of thiazolidinediones (TZDs) which act as high-affinity agonists of the nuclear receptor peroxisome-proliferator-activated receptor-γ (PPARγ), is clinically used as an antidiabetic drug which could attenuate the insulin resistance associated with obesity, hypertension, and impaired glucose tolerance in humans. However, recent studies reported that ROSI had significant anticancer effects on various human malignant tumor cells. Mounting evidence indicated that ROSI could exert anticancer effects through PPARγ-dependent or PPARγ-independent ways. In this review, we summarized the PPARγ-dependent antitumor activities of ROSI, which included apoptosis induction, inhibition of cell proliferation and cancer metastasis, reversion of multidrug resistance, reduction of immune suppression, autophagy induction, and antiangiogenesis; and the PPARγ-independent antitumor activities of ROSI, which included inhibition of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway, inhibition of prostaglandin E2 (PGE₂), increasing MAPK phosphatase 1 (MKP-1) expression and regulation of other apoptosis-related cell factors. In addition, we discussed the anti-cancer application of ROSI by monotherapy or combination therapy with present chemotherapeutic drugs in vitro and in vivo. Moreover, we reviewed the phase I cancer clinical trials related to ROSI combined with chemotherapeutics and phase II trials about the anti-cancer effects of ROSI monotherapy and the radiotherapy sensitivity of ROSI.

Novel Targets for Treating Ischemia-Reperfusion Injury in the Liver

Liver ischemia-reperfusion injury (IRI) is a major complication of hemorrhagic shock, liver transplantation, and other liver surgeries. It is one of the leading causes for post-surgery hepatic dysfunction, always leading to morbidity and mortality. Several strategies, such as low-temperature reperfusion and ischemic preconditioning, are useful for ameliorating liver IRI in animal models. However, these methods are difficult to perform in clinical surgeries. It has been reported that the activation of peroxisome proliferator activated receptor gamma (PPARγ) protects the liver against IRI, but with unidentified direct target gene(s) and unclear mechanism(s). Recently, FAM3A, a direct target gene of PPARγ, had been shown to mediate PPARγ’s protective effects in liver IRI. Moreover, noncoding RNAs, including LncRNAs and miRNAs, had also been reported to play important roles in the process of hepatic IRI. This review briefly discussed the roles and mechanisms of several classes of important molecules, including PPARγ, FAM3A, miRNAs, and LncRNAs, in liver IRI. In particular, oral administration of PPARγ agonists before liver surgery or liver transplantation to activate hepatic FAM3A pathways holds great promise for attenuating human liver IRI.

VSP-17, a New PPARγ Agonist, Suppresses the Metastasis of Triple-Negative Breast Cancer via Upregulating the Expression of E-Cadherin

Triple-negative breast cancer (TNBC), an aggressive subtype of breast cancer, shows higher metastases and relapse rates than other subtypes. The metastasis of TNBC is the main reason for the death of TNBC patients. Increasing evidence has shown that inhibiting the metastasis of TNBC is a good method for TNBC treatment. Here, VSP-17 was designed and synthesized as an agonist of PPARγ, evidenced by upregulating the expression of CD36 and increasing the activity of PPARγ reporter gene. VSP-17 obviously inhibited the migration and invasion process of MDA-MB-231 cells but showed little effect on the viability of MDA-MB-231 cells. Notably, VSP-17 could selectively promote the expression of E-cadherin without affecting the expression of BRMS1, CXCL12, MMP9, Orai1, Stim1, TGF-β, and VEGF. In addition, VSP-17 significantly suppressed the metastasis of liver and promoted the expression of E-cadherin in MDA-MB-231 xenograft model. In conclusion, VSP-17 inhibited the metastasis process of TNBC via upregulating the expression of E-cadherin.

Expression of B7-H4 and hepatitis B virus X in hepatitis B virus-related hepatocellular carcinoma

AIM: To investigate the expression and clinical significance of B7-H4 and hepatitis B virus X (HBx) protein in hepatitis B virus-related hepatocellular carcinoma (HBV-HCC).

METHODS: The expression of B7-H4 in the human HCC cell lines HepG2 and HepG2.2.15 were detected by western blot, flow cytometry, and immunofluorescence. The expression of B7-H4 and HBx in 83 HBV-HCC was detected by immunohistochemistry, and the relationship with clinicopathological features was analyzed. Paraffin sections were generated from 83 HBV-HCC patients (22 females and 61 males) enrolled in this study. The age of these patients ranged from 35 to 77 years, with an average of 52.5 ± 11.3 years. All experiments were approved by the Ethics Committees of the Second Affiliated Hospital, Zhejiang University School of Medicine.

RESULTS: B7-H4 was significantly upregulated in HepG2.2.15 cells compared to HepG2 cells. Specifically, the protein expression of B7-H4 in the lysates of HepG2 cells was more than that in HepG2.2.15 cells. In addition, HBx was expressed only in HepG2.2.15 cells. Similar data were obtained by flow cytometry. The positive rates of B7-H4 and HBx in the tissues of 83 HBV-HCC patients were 68.67% (57/83) and 59.04% (49/83), respectively. The expression of HBx was correlated with tumor node metastases (TNM) stage, and the expression of B7-H4 was positively correlated with HBx (r_s = 0.388; P < 0.01). The expression level of B7-H4 in HBx-positive HBV-HCC tissues was substantially higher than that in HBx-negative HBV-HCC tissues. The expression level of B7H4 was negatively related to tumor TNM stage.

CONCLUSION: Higher expression of HBx and B7-H4 was correlated with tumor progression of HBV-HCC, suggesting that B7-H4 may be involved in facilitating HBV-related hepatocarcinogenesis.