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23 result(s) for "Yu, Le-Xing"
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Role of nonresolving inflammation in hepatocellular carcinoma development and progression
Hepatocellular carcinoma (HCC) has become a leading cause of cancer-related death, making the elucidation of its underlying mechanisms an urgent priority. Inflammation is an adaptive response to infection and tissue injury under strict regulations. When the host regulatory machine runs out of control, nonresolving inflammation occurs. Nonresolving inflammation is a recognized hallmark of cancer that substantially contributes to the development and progression of HCC. The HCC-associated inflammation can be initiated and propagated by extrinsic pathways through activation of pattern-recognition receptors (PRRs) by pathogen-associated molecule patterns (PAMPs) derived from gut microflora or damage-associated molecule patterns (DAMPs) released from dying liver cells. The inflammation can also be orchestrated by the tumor itself through secreting factors that recruit inflammatory cells to the tumor favoring the buildup of a microenvironment. Accumulating datas from human and mouse models showed that inflammation promotes HCC development by promoting proliferative and survival signaling, inducing angiogenesis, evading immune surveillance, supporting cancer stem cells, activating invasion and metastasis as well as inducing genomic instability. Targeting inflammation may represent a promising avenue for the HCC treatment. Some inhibitors targeting inflammatory pathways have been developed and under different stages of clinical trials, and one (sorafenib) have been approved by FDA. However, as most of the data were obtained from animal models, and there is a big difference between human HCC and mouse HCC models, it is challenging on successful translation from bench to bedside.
The gut microbiome and liver cancer: mechanisms and clinical translation
Key Points Intestinal dysbiosis and increased bacterial translocation contribute to the pathophysiology of chronic liver disease (CLD) and hepatocarcinogenesis A large body of literature has demonstrated that targeting the gut-microbiota–liver axis can inhibit the development of hepatocellular carcinoma (HCC) in mice and rats Promising findings from these preclinical studies in mice and rats have not yet been translated to clinical settings, presenting therapeutic opportunities Targeting the gut–liver axis by nonabsorbable antibiotics such as rifaximin might not only prevent the development of HCC in patients with CLD, but additionally reduce other complications and improve survival Increasing evidence suggests that the gut microbiota are important modulators of chronic liver disease progression and the development of hepatocellular carcinoma. In this Review, Yu and Schwabe discuss the mechanisms by which the gut microbiota promote hepatocarcinogenesis, and explore therapeutic interventions with clinical potential. Hepatocellular carcinoma (HCC) is the third leading cause of worldwide cancer mortality. HCC almost exclusively develops in patients with chronic liver disease, driven by a vicious cycle of liver injury, inflammation and regeneration that typically spans decades. Increasing evidence points towards a key role of the bacterial microbiome in promoting the progression of liver disease and the development of HCC. Here, we will review mechanisms by which the gut microbiota promotes hepatocarcinogenesis, focusing on the leaky gut, bacterial dysbiosis, microbe-associated molecular patterns and bacterial metabolites as key pathways that drive cancer-promoting liver inflammation, fibrosis and genotoxicity. On the basis of accumulating evidence from preclinical studies, we propose the intestinal-microbiota–liver axis as a promising target for the simultaneous prevention of chronic liver disease progression and HCC development in patients with advanced liver disease. We will review in detail therapeutic modalities and discuss clinical settings in which targeting the gut-microbiota–liver axis for the prevention of disease progression and HCC development seems promising.
4‐phenylbutyric acid promotes hepatocellular carcinoma via initiating cancer stem cells through activation of PPAR‐α
Background and aims 4‐phenylbutyric acid (4‐PBA) is a low molecular weight fatty acid that is used in clinical practice to treat inherited urea cycle disorders. In previous reports, it acted as a chemical chaperone inhibiting endoplasmic reticulum (ER) stress and unfolded protein response signaling. A few studies have suggested its function against hepatic fibrosis in mice models. However, its role in hepatocarcinogenesis remained unknown. Methods 4‐PBA was administered alone or in combination with diethylnitrosamine to investigate its long‐term effect on liver tumorigenesis. The role of 4‐PBA in oncogene‐induced hepatocellular carcinoma (HCC) mice model using sleeping beauty system co‐expressed with hMet and β‐catenin point mutation (S45Y) was also observed. RNA‐seq and PCR array were used to screen the pathways and genes involved. In vitro and in vivo studies were conducted to explore the effect of 4‐PBA on liver and validate the underlying mechanism. Results 4‐PBA alone didn't cause liver tumor in long term. However, it promoted liver tumorigenesis in HCC mice models via initiation of liver cancer stem cells (LCSCs) through Wnt5b‐Fzd5 mediating β‐catenin signaling. Peroxisome proliferator‐activated receptors (PPAR)‐α induced by 4‐PBA was responsible for the activation of β‐catenin signaling. Thus, intervention of PPAR‐α reversed 4‐PBA‐induced initiation of LCSCs and HCC development in vivo. Further study revealed that 4‐PBA could not only upregulate the expression of PPAR‐α transcriptionally but also enhance its stabilization via protecting it from proteolysis. Moreover, high PPAR‐α expression predicted poor prognosis in HCC patients. Conclusions 4‐PBA could upregulate PPAR‐α to initiate LCSCs by activating β‐catenin signaling pathway, promoting HCC at early stage. Therefore, more discretion should be taken to monitor the potential tumor‐promoting effect of 4‐PBA under HCC‐inducing environment. 4‐PBA could promote HCC at early stage of tumor development in vivo. 4‐PBA initiated CSCs via activating Wnt5b‐Fzd5‐β‐catenin signaling pathway dependent of PPAR‐α activation. 4‐PBA could not only regulate the expression of PPAR‐α transcriptionally, but also stabilize it via direct binding.
Identification of important genes and drug repurposing based on clinical-centered analysis across human cancers
Identification of the functional impact of mutated and altered genes in cancer is critical for implementing precision oncology and drug repurposing. In recent years, the emergence of multiomics data from large, well-characterized patient cohorts has provided us with an unprecedented opportunity to address this problem. In this study, we investigated survival-associated genes across 26 cancer types and found that these genes tended to be hub genes and had higher K-core values in biological networks. Moreover, the genes associated with adverse outcomes were mainly enriched in pathways related to genetic information processing and cellular processes, while the genes with favorable outcomes were enriched in metabolism and immune regulation pathways. We proposed using the number of survival-related neighbors to assess the impact of mutations. In addition, by integrating other databases including the Human Protein Atlas and the DrugBank database, we predicted novel targets and anticancer drugs using the drug repurposing strategy. Our results illustrated the significance of multidimensional analysis of clinical data in important gene identification and drug development.
Opposing roles of hepatic stellate cell subpopulations in hepatocarcinogenesis
Hepatocellular carcinoma (HCC), the fourth leading cause of cancer mortality worldwide, develops almost exclusively in patients with chronic liver disease and advanced fibrosis 1 , 2 . Here we interrogated functions of hepatic stellate cells (HSCs), the main source of liver fibroblasts 3 , during hepatocarcinogenesis. Genetic depletion, activation or inhibition of HSCs in mouse models of HCC revealed their overall tumour-promoting role. HSCs were enriched in the preneoplastic environment, where they closely interacted with hepatocytes and modulated hepatocarcinogenesis by regulating hepatocyte proliferation and death. Analyses of mouse and human HSC subpopulations by single-cell RNA sequencing together with genetic ablation of subpopulation-enriched mediators revealed dual functions of HSCs in hepatocarcinogenesis. Hepatocyte growth factor, enriched in quiescent and cytokine-producing HSCs, protected against hepatocyte death and HCC development. By contrast, type I collagen, enriched in activated myofibroblastic HSCs, promoted proliferation and tumour development through increased stiffness and TAZ activation in pretumoural hepatocytes and through activation of discoidin domain receptor 1 in established tumours. An increased HSC imbalance between cytokine-producing HSCs and myofibroblastic HSCs during liver disease progression was associated with increased HCC risk in patients. In summary, the dynamic shift in HSC subpopulations and their mediators during chronic liver disease is associated with a switch from HCC protection to HCC promotion. Subpopulations of cytokine-producing and myofibroblastic hepatic stellate cells, identified by single-cell RNA sequencing, protect against or promote the development of hepatocellular carcinoma via high expression of hepatocyte growth factor or type I collagen, respectively..
Platelets promote tumour metastasis via interaction between TLR4 and tumour cell-released high-mobility group box1 protein
Increasing evidence suggests that TLR4 expression by tumour cells promotes tumour progression, but it is unclear whether TLR4 is involved in metastasis. Here we show that TLR4 deficiency significantly diminishes experimental lung metastasis without affecting primary tumour growth. Bone marrow transplantation experiment and application of antiplatelet agents in mice demonstrate that TLR4 on platelets plays an important role in metastasis. TLR4 is critical for platelet–tumour cell interaction in vitro . Furthermore, high-mobility group box1 (HMGB1) neutralization attenuates platelet–tumour cell interaction in vitro and metastasis in vivo in a TLR4-dependent manner, indicating that tumour cell-released HMGB1 is the key factor that interacts with TLR4 on platelets and mediates platelet–tumour cell interaction, which promotes metastasis. These findings demonstrate a mechanism by which platelets promote tumour cell metastasis and suggest TLR4, and its endogenous ligand HMGB1 as targets for antimetastatic therapies. Factors affecting the fate of disseminating tumour cells in the circulation play a critical role in metastasis. Here the authors show that TLR4 on platelets promotes their adhesion to tumour cells and enhances metastasis.
Abrogation of Local Cancer Recurrence After Radiofrequency Ablation by Dendritic Cell-based Hyperthermic Tumor Vaccine
Local recurrence is a therapeutic challenge for radiofrequency ablation (RFA) in treatment of small solid focal malignancies. Here we show that RFA induced heat shock proteins (HSPs) expression and high mobility group box-1 (HMGB1) translocation in xenografted melanoma, which might create a proinflammatory microenvironment that favors tumor antigen presentation and activation of the effector T cells. On this basis, we investigate whether a prime-boost strategy combining a prime with heat-shocked tumor cell lysate-pulsed dendritic cell (HT-DC) followed by an in situ boost with radiofrequency thermal ablation can prevent local tumor recurrence. The combination treatment with HT-DC and RFA showed potent antitumor effects, with ≥90% of tumor recurrence abrogated following RFA treatment. By contrast, prevaccination with unheated tumor lysate-pulsed DC had little effect on tumor relapse. Analysis of the underlying mechanism revealed that splenocytes from mice treated with HT-DC plus RFA contained significantly more tumor-specific, IFN-γ-secreting T cells compared with control groups. Moreover, adoptive transfer of splenocytes from successfully treated tumor-free mice protected naive animals from tumor recurrence following RFA, and this was mediated mainly by CD8+ T cells. Therefore, the optimal priming for the DC vaccination before RFA is important for boosting antigen-specific T cell responses and prevention of cancer recurrence.
In vitro assessment of the glucose-lowering effects of berberrubine-9-O-β-D-glucuronide, an active metabolite of berberrubine
Berberrubine (BRB) is the primary metabolite of berberine (BBR) that has shown a stronger glucose-lowering effect than BBR in vivo. On the other hand, BRB is quickly and extensively metabolized into berberrubine-9-O-β-D-glucuronide (BRBG) in rats after oral administration. In this study we compared the pharmacokinetic properties of BRB and BRBG in rats, and explored the mechanisms underlying their glucose-lowering activities. C57BL/6 mice with HFD-induced hyperglycemia were administered BRB (50 mg·kg^-1·d^-1, ig) for 6 weeks, which caused greater reduction in the plasma glucose levels than those caused by BBR (120 mg·kg^-1·d^-1) or BRB (25 mg·kg^-1·d^-1). In addition, BRB dose-dependently decreased the activity of α-glucosidase in gut of the mice. After oral administration of BRB in rats, the exposures of BRBG in plasma at 3 different dosages (10, 40, 80 mg/kg) and in urine at different time intervals (0-4, 4-10, 10-24 h) were dramatically greater than those of BRB. In order to determine the effectiveness of BRBG in reducing glucose levels, we prepared BRBG from the urine pool of rats, and identified and confirmed it through LC-MS-IT-TOF and NMR spectra. In human normal liver cell line 1_-02 in vitro, treatment with BRB or BRBG (5, 20, 50 pmol/L) increased glucose consumption, enhanced glycogenesis, stimulated the uptake of the glucose analog 2-NBDG, and modulated the mRNA levels of glucose-6-phosphatase and hexokinase. However, both BBR and BRB improved 2-NBDG uptake in insulin-resistant L-02 cells, while BRBG has no effect. In conclusion, BRB exerts a stronger glucose-lowering effect than BBR in HFD-induced hyperglycemia mice. Although BRB significantly stimulated the insulin sensitivity and glycolysis in vitro, BRBG may have a greater contribution to the glucose-lowering effect because it has much greater system exposure than BRB after oral administration of BRB. The results suggest that BRBG is a potential agent for reducing glucose levels.
Adaptive changes in autophagy after UPS impairment in Parkinson's disease
Ubiquitin-proteasome system (UPS) and autophagosome-lysosome pathway (ALP) are the most important machineries respon- sible for protein degradation in Parkinson's disease (PD). The aim of this study is to investigate the adaptive alterations in autophagy upon proteasome inhibition in dopaminergic neurons in vitro and in vivo. Methods: Human dopaminergic neuroblastoma SH-SYSY cells were treated with the proteasome inhibitor lactacystin (5 pmol/L) for 5, 12, or 24 h. The expression of autophagy-related proteins in the cells was detected with immunoblotting. UPS-impaired mouse mode of PD was established by microinjection of lactacystin (2 pg) into the left hemisphere of C57BL/6 mice that were sacrificed 2 or 4 weeks later. The midbrain tissues were dissected to assess alterations in autophagy using immunofluorescence, immunoblotting and electron microscopy assays. Results: Both in SH-SY5Y cells and in the midbrain of UPS-impaired mouse model of PD, treatment with lactacystin significantly increased the expression levels of LC3-1/II and Beclin 1, and reduced the levels of p-mTOR, mTOR and p62/SQSTM1. Furthermore, lactacystin treatment in UPS-impaired mouse model of PD caused significant loss of TH-positive neurons in the substantia nigra, and dramatically increased the number of autophagosomes in the left TH-positive neurons. Conclusion: Inhibition of UPS by lactacystin in dopaminergic neurons activates another protein degradation system, the ALP, which includes both the mTOR signaling pathway and Beclin 1-associated pathway.