Maintenance of glutamine synthetase expression alleviates endotoxin-induced sepsis via alpha-ketoglutarate-mediated demethylation.

Glutamine synthetase (Glul) is the enzyme that synthesizes endogenous glutamine, which is responsible for critical metabolic pathways and the immune system. However, the role of Glul in regulating endotoxin (lipopolysaccharide, LPS)-induced sepsis remains unclear. Here, we found that Glul expression in macrophages was significantly inhibited in endotoxemia, and that Glul deletion induced macrophages to differentiate into the pro-inflammatory type and aggravated sepsis in mice. Mechanistically, TLR4/NF-κB-induced alpha-ketoglutarate (α-KG) depletion inhibits Glul expression through H3K27me3-mediated methylation in septic mice. Both Glul overexpression with adeno-associated virus (AAV) and restoration by replenishing α-KG can alleviate the severity of sepsis. In conclusion, the study demonstrated that Glul can regulate LPS-induced sepsis and provides a novel strategy for the treatment of this disease.

The Role of Exhaled Hydrogen Sulfide in the Diagnosis of Colorectal Adenoma.

PURPOSE: Exhaled determination can detect metabolite hydrogen sulfide in the intestine. We aim to analyze the predictive value of hydrogen sulfide in the diagnosis of colorectal adenoma. METHODS: We recruited seventy patients diagnosed with colorectal adenoma as the observation group and sixty-six healthy subjects as the control group. The colorectal adenoma was diagnosed by colonoscopy at the Endoscopy Center of Huashan Hospital affiliated to Fudan University from June 2018 to November 2019. Exhaled gas was collected through the nose and mouth, respectively, and hydrogen sulfide in exhaled gas was determined according to the manufacturer's instructions. RESULTS: Receiver operating characteristic (ROC) curve was analyzed based on the exhaled data of the observation group and the control group. The ROC curve showed an area under ROC curve (AUC) 0.724 for nasal exhaled H2S, which had a diagnostic value. When nasal exhaled H2S was >13.3 part per billion (ppb), the sensitivity and the specificity of predicting colorectal adenoma were 57% and 78%, respectively. The exhaled H2S of the observation group was significantly different from that of the control group. The AUC value was 0.716 as a prognostic factor of colorectal adenoma. As exhaled H2S was >28.8 ppb, the sensitivity and the specificity of predicting colorectal adenoma were 63% and 77%, respectively. CONCLUSION: Exhaled and nasal H2S determination has a predictive value for colorectal adenoma as a novel and noninvasive method. Therefore, it is worth conducting more research to analyze exhaled and nasal H2S.

Aldehyde dehydrogenase-2 (ALDH2) opposes hepatocellular carcinoma progression by regulating AMP-activated protein kinase signaling in mice.

Potential biomarkers that can be used to determine prognosis and perform targeted therapies are urgently needed to treat patients with hepatocellular carcinoma (HCC). To meet this need, we performed a screen to identify functional genes associated with hepatocellular carcinogenesis and its progression at the transcriptome and proteome levels. We identified aldehyde dedydrogenase-2 (ALDH2) as a gene of interest for further study. ALDH2 levels were significantly lower at the mRNA and protein level in tumor tissues than in normal tissues, and they were even lower in tissues that exhibited increased migratory capacity. A study of clinical associations showed that ALDH2 is correlated with survival and multiple migration-associated clinicopathological traits, including the presence of metastasis and portal vein tumor thrombus. The result of overexpressing or knocking down ALDH2 showed that this gene inhibited migration and invasion both in vivo and in vitro. We also found that ALDH2 altered the redox status of cells by regulating acetaldehyde levels and that it further activated the AMP-activated protein kinase (AMPK) signaling pathway. CONCLUSION: Decreased levels of ALDH2 may indicate a poor prognosis in HCC patients, while forcing the expression of ALDH2 in HCC cells inhibited their aggressive behavior in vitro and in mice largely by modulating the activity of the ALDH2-acetaldehyde-redox-AMPK axis. Therefore, identifying ALDH2 expression levels in HCC might be a useful strategy for classifying HCC patients and for developing potential therapeutic strategies that specifically target metastatic HCC. (Hepatology 2017;65:1628-1644).

Hippocalcin-like 1 suppresses hepatocellular carcinoma progression by promoting p21(Waf/Cip1) stabilization by activating the ERK1/2-MAPK pathway.

UNLABELLED: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death. However, the underlying mechanism during hepatocarcinogenesis remains unclarified. Stable isotope labeling by amino acids in cell culture (SILAC) is a powerful quantitative strategy for proteome-wide discovery of novel biomarkers in cancers. Hippocalcin-like 1 (HPCAL1) is a calcium sensor protein. However, the biological function of HPCAL1 is poorly understood in cancers, including HCC. Herein, HPCAL1 was identified by SILAC as a novel hepatocarcinogenesis suppressor down-regulated in HCC cell lines and tissues. Importantly, lost expression of HPCAL1 was associated with worse prognosis of HCC patients. Interestingly, secreted HPCAL1 protein in the plasma dropped dramatically in HCC patients compared with healthy donors. Receiver operating characteristic curve analysis showed that serum HPCAL1 at a concentration of 8.654 ng/mL could better predict HCC. Furthermore, ectopic expression of HPCAL1 suppresses cell proliferation, while depletion of HPCAL1 led to increased cell growth both in vitro and in vivo. Mechanistically, HPCAL1 directly interacted with p21(Waf/Cip1) in the nucleus, which requires the EF-hand 4 motif of HPCAL1 and the Cy1 domain of p21. This interaction stabilized p21(Waf/Cip1) in an extracellular signal-regulated kinase 1/2-mitogen-activated protein kinase-dependent manner, which subsequently prevented p21(Waf/Cip1) proteasomal degradation by disrupting SCF(Skp2) and CRL4(Cdt2) E3 ligase complexes, resulting in increased protein stability and inhibitory effect of p21(Waf/Cip1). Notably, the tumor suppressive function of HPCAL1 was dependent on p21 in vitro and in vivo. Consistent with this observation, expression of HPCAL1 and p21(Waf/Cip1) was positively correlated in HCC tissues. CONCLUSION: These findings highlight a novel tumor suppressor upstream of p21(Waf/Cip1) in attenuating cell cycle progression and provide a promising diagnostic and prognostic factor, as well as a potential therapeutic target for HCC.

Acetyl-coenzyme A carboxylase alpha promotion of glucose-mediated fatty acid synthesis enhances survival of hepatocellular carcinoma in mice and patients.

UNLABELLED: Solid tumors often suffer from suboptimal oxygen and nutrient supplies. This stress underlies the requirement for metabolic adaptation. Aberrantly activated de novo lipogenesis is critical for development and progression of human hepatocellular carcinoma (HCC). However, whether de novo lipogenesis influences biological behaviors of HCCs under conditions of metabolic stress are still poorly understood. Here, we show that HCCs display distinct levels of glucose-derived de novo lipogenesis, which are positively correlated with their survival responses to glucose limitation. The enhanced lipogenesis in HCCs is characterized by an increased expression of rate-limiting enzyme acetyl-coenzyme A carboxylase alpha (ACCα). ACCα-mediated fatty acid (FA) synthesis determines the intracellular lipid content that is required to maintain energy hemostasis and inhibit cell death by means of FA oxidation (FAO) during metabolic stress. In accord, overexpression of ACCα facilitates tumor growth. ACCα forms a complex with carnitine palmitoyltransferase 1A (CPT1A) and prevents its mitochondria distribution under nutrient-sufficient conditions. During metabolic stress, phosphorylation of ACCα leads to dissociation of the complex and mitochondria localization of CPT1A, thus promoting FAO-mediated cell survival. Therefore, ACCα could provide both the substrate and enzyme storage for FAO during glucose deficiency. Up-regulation of ACCα is also significantly correlated with poorer overall survival and disease recurrence postsurgery. Multivariate Cox's regression analysis identified ACCα as an effective predictor of poor prognosis. CONCLUSION: These results present novel mechanistic insight into a pivotal role of ACCα in maintaining HCC survival under metabolic stress. It could be exploited as a novel diagnostic marker and therapeutic target.

Interleukin-1ß/Iinterleukin-1 receptor-associated kinase 1 inflammatory signaling contributes to persistent Gankyrin activation during hepatocarcinogenesis.

UNLABELLED: Hepatocellular carcinoma (HCC) is a prototype of inflammation-associated cancer. Oncoprotein Gankyrin, which mostly increases in HCC, plays a critical role in HCC development and metastasis. However, the exact mechanism of Gankyrin up-regulation in HCC remains unclear. A Gankyrin luciferase reporter was developed to screen a potential regulator for Gankyrin from a list of proinflammatory cytokines, and interleukin (IL)-1ß was found as one of its activators. In clinical premalignant and malignant liver disease samples, enhanced IL-1ß/interleukin-1 receptor-associated kinase 1 (IRAK-1) signaling accompanied by increased Gankyrin was observed. Lower expression of Gankyrin and phospho-IRAK-1 are favorable prognostic markers for HCC. A similar correlation was observed in the diethylnitrosamine (DEN) model of rat hepatocarcinogenesis. The results from Gankyrin reporter activity, real-time polymerase chain reaction, or immunoblotting further confirmed the up-regulation of Gankyrin by IL-1ß/IRAK-1 inflammatory signaling. Moreover, a series of Gankyrin's truncated reporters were constructed, and electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) were performed to analyze the properties of Gankyrin promoter. Mechanistically, the core promoter of Gankyrin contains the binding site of nuclear factor Y (NF-Y) family members, which can recruit histone acetyltransferase coactivator E1A-binding protein p300 (p300) or CREB-binding protein (CBP) to promote Gankyrin transcription. Conversely, knockdown of NF-Y, p300, or CBP inhibits Gankyrin expression. IL-1ß stimulation causes sequential phosphorylation of IRAK-1, c-Jun N-terminal kinase (JNK), and p300 and enhances recruitment of the p300/CBP/NF-Y complex to Gankyrin promoter. Inhibition of phospho-JNK impairs IL-1ß/IRAK-1 signaling-mediated up-regulation of Gankyrin. CONCLUSION: The finding of IL-1ß/IRAK-1 signaling promoting Gankyrin expression through JNK and NF-Y/p300/CBP complex provides a fresh view on inflammation-enhanced hepatocarcinogenesis.

Role of exhaled hydrogen sulfide in the diagnosis of colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is often accompanied by increased excretion of hydrogen sulfide (H2S). This study aimed to explore the value of exhaled H2S in the diagnosis of CRC. METHODS: A total of 80 people with normal colonoscopy results and 57 patients with CRC were enrolled into the present observational cohort study. Exhaled oral and nasal H2S were detected by Nanocoulomb breath analyser. Results were compared between the two groups. Receiver operating characteristic (ROC) curves were analysed and area under the curves (AUCs) were calculated to assess the diagnostic value of exhaled H2S. Meanwhile, the clinicopathological features, including gender, lesion location and tumour staging of patients with CRC, were also collected and analysed. RESULTS: The amount of exhaled H2S from patients with CRC was significantly higher than that of those with normal colonoscopy results. The ROC curve showed an AUC value of 0.73 and 0.71 based on oral and nasal H2S detection, respectively. The exhaled H2S in patients with CRC was correlated with gender, lesion location and tumour progression, including depth of invasion, lymphatic metastasis and TNM (Tumor, Lymph Nodes, Metastasis) staging. CONCLUSION: Exhaled H2S analysis is a convenient and non-invasive detection method for diagnosing CRC, suggesting a potential role in population screening for CRC.

Disturbance of Ca2+ homeostasis converts pro-Met into non-canonical tyrosine kinase p190MetNC in response to endoplasmic reticulum stress in MHCC97 cells.

c-Met, the tyrosine-kinase receptor for hepatocyte growth factor, plays a critical role in the tumorigenesis of hepatocellular carcinoma (HCC). However, the underlying mechanism remains incompletely understood. The mature c-Met protein p190Met(αß) (consists of a α subunit and a ß subunit) is processed from pro-Met. Here we show that pro-Met is processed into p190Met(NC) by sarco/endoplasmic reticulum calcium-ATPase (SERCA) inhibitor thapsigargin. p190Met(NC) compensates for the degradation of p190Met(αß) and protects human HCC cells from apoptosis mediated by endoplasmic reticulum (ER) stress. In comparison with p190Met(αß), p190Met(NC) is not cleaved and is expressed as a single-chain polypeptide. Thapsigargin-initiated p190Met(NC) expression depends on the disturbance of ER calcium homeostasis. Once induced, p190Met(NC) is activated independent of hepatocyte growth factor engagement. p190Met(NC) contributes to sustained high basal activation of c-Met downstream pathways during ER calcium disturbance-mediated ER stress. Both p38 MAPK-promoted glucose-regulated protein 78 (GRP78) expression and sustained high basal activation of PI3K/Akt and MEK/ERK are involved in the cytoprotective function of p190Met(NC). Importantly, the expression of p190Met(NC) is detected in some HCC cases. Taken together, these data provide a potential mechanism to explain how c-Met promotes HCC cells survival in response to ER stress. We propose that context-specific processing of c-Met protein is implicated in HCC progression in stressful microenvironments.

p53 promotes inflammation-associated hepatocarcinogenesis by inducing HMGB1 release.

BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) develops in response to chronic hepatic injury. Although induced cell death is regarded as the major component of p53 tumor-suppressive activity, we recently found that sustained p53 activation subsequent to DNA damage promotes inflammation-associated hepatocarcinogenesis. Here we aim at exploring the mechanism linking p53 activation and hepatic inflammation during hepatocarcinogenesis. METHODS: p53(-/-) hepatocytes expressing inducible p53 and primary wild type hepatocytes were treated to induce p53 expression. The supernatants were collected and analyzed for the presence of released inflammatory cytokines. Ethyl pyruvate was used in a rat model of carcinogen-induced hepatocarcinogenesis to examine its effect on p53-dependent chronic hepatic injury, inflammation, and tumorigenesis. RESULTS: Here we show that cytoplasmic translocation and circulating levels of potent inflammatory molecule high-mobility group protein 1 (HMGB1) were greater in wild type rats than in p53(+/-) rats following carcinogen administration. Restoration of p53 expression in p53-null hepatocytes or induction of endogenous p53 in wild type hepatocytes gives rise to the release of HMGB1. Administration of the HMGB1 release inhibitor ethyl pyruvate, which does not affect p53-mediated hepatic apoptosis, substantially prevented carcinogen-induced cirrhosis and tumorigenesis in rat livers. CONCLUSIONS: These results suggest that although p53 is usually regarded as a tumor suppressor, its constant activation can promote pro-tumorigenic inflammation, at least in part, via inducing HMGB1 release. Application of HMGB1 inhibitors when restoring p53 in cancer therapy might protect against pro-tumorigenic effects while leaving p53-mediated clearance of malignant cells intact.

Hepatitis B virus X (HBx) induces tumorigenicity of hepatic progenitor cells in 3,5-diethoxycarbonyl-1,4-dihydrocollidine-treated HBx transgenic mice.

UNLABELLED: Hepatitis B virus X (HBx) protein is implicated in hepatitis B virus (HBV)-associated liver carcinogenesis. However, it remains unclear whether HBx-expressing hepatic progenitor cells (HPCs) are attributed to liver tumor formation. In this study, by using HBx transgenic mice and a 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-induced liver injury model, the relationship between HBx expression and tumorigenicity of HPCs was analyzed. Compared with control mice, an elevated number of EpCAM(+) cells with characteristics of HPCs was observed in HBx mice after 1 month and 4 months of DDC diet feeding. All HBx transgenic mice developed liver tumors characterized by histological features of both hepatocellular carcinoma (HCC) and cholangiocarcinoma after 7 months of DDC feeding. Notably, EpCAM(+) HPCs isolated from premalignant HBx mice exposed to a DDC diet for 4 months formed subcutaneous mixed-lineage tumors (four out of six) in nonobese diabetic/severe-combined immunodeficient (NOD/SCID) mice, and none of the cells from wildtype (WT) induced tumor, indicating that HBx may induce malignant transformation of HPCs that contributes to tumorigenesis. We also found higher titers of circulating interleukin (IL)-6, activities of IL-6/STAT3, and Wnt/ß-catenin signaling pathways in HBx transgenic mice, suggesting HBx may induce intrinsic changes in HPCs by way of the above signaling that enables HPCs with tumorigenicity potential. Finally, clinical evidence showed that high HBx expression in human HBV-related HCC was statistically associated with expansion of EpCAM(+) or OV6(+) tumor cells and aggressive clinicopathologic features. CONCLUSION: HBx induces intrinsic cellular transformation promoting the expansion and tumorigenicity of HPCs in DDC-treated mice, which may be a possible origin for liver cancer induced by chronic hepatitis infection.

Ultrasensitive quantification of trace amines based on N-phosphorylation labeling chip 2D LC-QQQ/MS.

Trace amines (TAs) are metabolically related to catecholamine and associated with cancer and neurological disorders. Comprehensive measurement of TAs is essential for understanding pathological processes and providing proper drug intervention. However, the trace amounts and chemical instability of TAs challenge quantification. Here, diisopropyl phosphite coupled with chip two-dimensional (2D) liquid chromatography tandem triple-quadrupole mass spectrometry (LC-QQQ/MS) was developed to simultaneously determine TAs and associated metabolites. The results showed that the sensitivities of TAs increased up to 5520 times compared with those using nonderivatized LC-QQQ/MS. This sensitive method was utilized to investigate their alterations in hepatoma cells after treatment with sorafenib. The significantly altered TAs and associated metabolites suggested that phenylalanine and tyrosine metabolic pathways were related to sorafenib treatment in Hep3B cells. This sensitive method has great potential to elucidate the mechanism and diagnose diseases considering that an increasing number of physiological functions of TAs have been discovered in recent decades.

OV6⁺ tumor-initiating cells contribute to tumor progression and invasion in human hepatocellular carcinoma.

BACKGROUND & AIMS: Accumulating evidence suggests the involvement of tumor-initiating cells (T-ICs) in cancer genesis, but whether liver T-ICs contribute to HCC invasion and metastasis remains unclear. METHODS: OV6(+) T-ICs were isolated from SMMC7721 and HuH7 cell lines by magnetic sorting. Characteristics of T-ICs were assessed by in vitro and mouse xenograft assays. Expression of OV6 was determined by immunostaining in specimens from 218 HCC patients, and Kaplan-Meier survival analysis was used to determine the correlation of OV6 expression with prognosis. RESULTS: OV6(+) T-ICs isolated from HCC cell lines not only possess a higher capacity to form tumor spheroids in vitro, but also had a greater potential to form tumors when implanted in non-obese diabetic/severe combined immunodeficient mice, suggesting their elevated self-renewal capacity and tumorigenicity. Moreover, OV6(+) T-ICs exhibited more invasive and metastatic potentials both in vitro and in vivo. Patients with more OV6(+) tumor cells were associated with aggressive clinicopathologic features and poor prognosis. CXCR4 is expressed at higher levels in OV6(+) cells. Recombinant stromal cell-derived factor-1 (SDF-1) treatment expanded the OV6(+) HCC T-ICs population, by sustaining the stem cell property of OV6(+) cells. The SDF-1 effect was blocked by a specific CXCR4 inhibitor, AMD3100, or transfection of siRNA targeting CXCR4. CONCLUSIONS: OV6(+) HCC cells may represent a subpopulation of T-ICs with augmented invasion and metastasis potential, which contribute to progression and metastasis of HCC. The SDF-1/CXCR4 axis also provides therapeutic targets for elimination of liver T-ICs.

Profound impact of gut homeostasis on chemically-induced pro-tumorigenic inflammation and hepatocarcinogenesis in rats.

BACKGROUND & AIMS: Due to its anatomic connection, the liver is constantly exposed to gut-derived bacterial products or metabolites. Disruption of gut homeostasis is associated with many human diseases. The aim of this study was to determine the role of gut homeostasis in initiation and progression of hepatocellular carcinoma (HCC). METHODS: Disruption of intestinal homeostasis by penicillin or dextran sulfate sodium (DSS) and its restoration by probiotics were applied in a diethylnitrosamine (DEN) model of rat hepatocarcinogenesis. RESULTS: Patients with liver cirrhosis and HCC had significantly increased serum endotoxin levels. Chronic DEN treatment of rats was associated with an imbalance of subpopulations of the gut microflora including a significant suppression of Lactobacillus species, Bifidobacterium species and Enterococcus species as well as intestinal inflammation. Induction of enteric dysbacteriosis or intestinal inflammation by penicillin or DSS, respectively, significantly promoted tumor formation. Administration of probiotics dramatically mitigated enteric dysbacteriosis, ameliorated intestinal inflammation, and most importantly, decreased liver tumor growth and multiplicity. Interestingly, probiotics not only inhibited the translocation of endotoxin, which bears pathogen-associated molecular patterns (PAMPs) but also the activation of damage-associated molecular patterns (DAMPs) such as high-mobility group box 1 (HMGB1). As a result, the production of pro- and anti-inflammatory cytokines was skewed in favor of a reduced tumorigenic inflammation in the liver. CONCLUSIONS: The data highlights the importance of gut homeostasis in the pathogenesis of HCC. Modulation of the gut microbiota by probiotics may represent a new avenue for therapeutic intervention to treat or prevent HCC development.

Effects of Immune Cells on Intestinal Stem Cells: Prospects for Therapeutic Targets.

The intestinal epithelium undergoes rapid cell turnover to maintain the integrity of the mucosal barrier, which is driven by the proliferation and differentiation of intestinal stem cells (ISCs). Due to their properties, ISCs are not only vulnerable targets during intestinal damage, but also act as the resources responsible for repair and regeneration. Moreover, the intestinal tract is the largest immune organ in the body, with the greatest number of immune cells including, but not limited to, macrophages, innate lymphoid cells and T cells. With the advance of intestinal organoid culture systems and single-cell RNA sequencing, the effects of immune cells on ISCs have been initially explored. As a component of the stem cell niche, these activated immune cells and their corresponding cytokines directly modulate apoptosis or survival of ISCs, leading to either destruction or protection of the intestinal epithelium in immune-mediated diseases, such as inflammatory bowel disease and graft-versus-host disease. In this review, we describe the effects of various immune cells on ISCs, as well as the mechanisms underlying these effects. We also highlight the remarkable role of ISCs in intestinal pathogenesis and raise the possibility of developing novel and effective therapeutic strategies for immune-mediated diseases based on ISCs.

Phenylalanine impairs insulin signaling and inhibits glucose uptake through modification of IRß.

Whether amino acids act on cellular insulin signaling remains unclear, given that increased circulating amino acid levels are associated with the onset of type 2 diabetes (T2D). Here, we report that phenylalanine modifies insulin receptor beta (IRß) and inactivates insulin signaling and glucose uptake. Mice fed phenylalanine-rich chow or phenylalanine-producing aspartame or overexpressing human phenylalanyl-tRNA synthetase (hFARS) develop insulin resistance and T2D symptoms. Mechanistically, FARS phenylalanylate lysine 1057/1079 of IRß (F-K1057/1079), inactivating IRß and preventing insulin from promoting glucose uptake by cells. SIRT1 reverse F-K1057/1079 and counteract the insulin-inactivating effects of hFARS and phenylalanine. F-K1057/1079 and SIRT1 levels in white blood cells from T2D patients are positively and negatively correlated with T2D onset, respectively. Blocking F-K1057/1079 with phenylalaninol sensitizes insulin signaling and relieves T2D symptoms in hFARS-transgenic and db/db mice. These findings shed light on the activation of insulin signaling and T2D progression through inhibition of phenylalanylation.

Targeting mTORC2/HDAC3 Inhibits Stemness of Liver Cancer Cells Against Glutamine Starvation.

Cancer cells are addicted to glutamine. However, cancer cells often suffer from glutamine starvation, which largely results from the fast growth of cancer cells and the insufficient vascularization in the interior of cancer tissues. Herein, based on clinical samples, patient-derived cells (PDCs), and cell lines, it is found that liver cancer cells display stem-like characteristics upon glutamine shortage due to maintaining the stemness of tumor initiating cells (TICs) and even promoting transformation of non-TICs into stem-like cells by glutamine starvation. Increased expression of glutamine synthetase (GS) is essential for maintaining and promoting stem-like characteristics of liver cancer cells during glutamine starvation. Mechanistically, glutamine starvation activates Rictor/mTORC2 to induce HDAC3-mediated deacetylation and stabilization of GS. Rictor is significantly correlated with the expression of GS and stem marker OCT4 at tumor site, and closely correlates with poor prognosis of hepatocellular carcinomas. Inhibiting components of mTORC2-HDAC3-GS axis decrease TICs and promote xenografts regression upon glutamine-starvation therapy. Collectively, the data provides novel insights into the role of Rictor/mTORC2-HDAC3 in reprogramming glutamine metabolism to sustain stemness of cancer cells. Targeting Rictor/HDAC3 may enhance the efficacy of glutamine-starvation therapy and limit the rapid growth and malignant progression of tumors.

Endotoxin accumulation prevents carcinogen-induced apoptosis and promotes liver tumorigenesis in rodents.

UNLABELLED: Increasing evidence suggests that the presence of endotoxemia is of substantial clinical relevance to patients with cirrhosis, but it is unclear whether and how gut-derived LPS amplifies the tumorigenic response of the liver. We found that the circulating levels of LPS were elevated in animal models of carcinogen-induced hepatocarcinogenesis. Reduction of LPS using antibiotics regimen in rats or genetic ablation of its receptor Toll-like receptor 4 (TLR4) in mice prevented excessive tumor growth and multiplicity. Additional investigation revealed that TLR4 ablation sensitizes the liver to carcinogen-induced toxicity via blocking NF-κB activation and sensitizing the liver to reactive oxygen species (ROS)-induced toxicity, but lessens inflammation-mediated compensatory proliferation. Reconstitution of TLR4-expressing myeloid cells in TLR4-deficient mice restored diethylnitrosamine (DEN)-induced hepatic inflammation and proliferation, indicating a paracrine mechanism of LPS in tumor promotion. Meanwhile, deletion of gut-derived endotoxin suppressed DEN-induced cytokine production and compensatory proliferation, whereas in vivo LPS pre-challenge promotes hepatocyte proliferation. CONCLUSION: Our data indicate that sustained LPS accumulation represents a pathological mediator of inflammation-associated hepatocellular carcinoma (HCC) and manipulation of the gut flora to prevent pathogenic bacterial translocation and endotoxin absorption may favorably influence liver function in patients with cirrhosis who are at risk of developing HCC.

Protective Effects of Aminooxyacetic Acid on Colitis Induced in Mice with Dextran Sulfate Sodium.

As a known inhibitor of pyridoxal phosphate-dependent transaminase glutamic-oxaloacetic transaminase 1 (GOT1), aminooxyacetic acid (AOAA) has been pointed out to have potential pharmacological effects in antiepileptic, anticonvulsant, antibacterial, cancer cell proliferation inhibition, and acute myocardial infarction (MI) relief. However, its role in inflammatory bowel disease (IBD) has not been reported. Through the in vivo experiment of dextran sulfate sodium- (DSS-) induced colitis in mice, it was found that AOAA significantly attenuated the symptoms, signs, and pathological changes of colitis. In addition, AOAA treatment prevented gut barrier damages by enhancing the expression of zona occludens- (ZO-) 1, occludin, claudin-1, and E-cadherin and recovering the upregulation of the most abundant intermediate filament protein (vimentin). Moreover, the release of interleukin- (IL-) 1ß, IL-6, and tumour necrosis factor- (TNF-) α was suppressed, yet the level of IL-10 was upregulated by AOAA treatment compared to the model group. Furthermore, it was shown that AOAA administration boosted M2-like phenotype and effectively reduced M1 macrophage phenotype in the lamina propria of mouse colonic epithelium. Similarly, the effect of AOAA was verified in vitro. AOAA effectively inhibited the classically activated M1 macrophage phenotype and proinflammatory cytokine (IL-1ß, TNF-α, and IL-6) expression induced by lipopolysaccharide (LPS) and promoted M2-like phenotype. Collectively, this study reveals for the first time that short-term treatment of AOAA can significantly alleviate DSS-induced acute colitis by regulating intestinal barrier function and macrophage polarization, which provides a theoretical basis for the potential use of AOAA in the treatment of IBD.

Fatty acid transport protein-5 (FATP5) deficiency enhances hepatocellular carcinoma progression and metastasis by reprogramming cellular energy metabolism and regulating the AMPK-mTOR signaling pathway.

Aberrant lipid metabolism is an essential feature of hepatocellular carcinoma (HCC). Fatty acid transport protein-5 (FATP5) is highly expressed in the liver and is involved in the fatty acid transport pathway. However, the potential role of FATP5 in the pathogenesis of HCC remains largely unknown. Herein, we showed that FATP5 was downregulated in HCC tissues and even much lower in vascular tumor thrombi. Low expression of FATP5 was correlated with multiple aggressive and invasive clinicopathological characteristics and contributed to tumor metastasis and a poor prognosis in HCC patients. FATP5 inhibited the epithelial-mesenchymal transition (EMT) process and suppressed HCC cell migration and invasion, while silencing FATP5 had the opposite effects. Mechanistically, knockdown of FATP5 promoted cellular glycolytic flux and ATP production, thus suppressing AMP-activated protein kinase (AMPK) and activating its downstream signaling mammalian target of rapamycin (mTOR) to support HCC progression and metastasis. Activation of AMPK using metformin reversed the EMT program and impaired the metastatic capacity of FATP5-depleted HCC cells. Collectively, FATP5 served as a novel suppressor of HCC progression and metastasis partly by regulating the AMPK/mTOR pathway in HCC, and targeting the FATP5-AMPK axis may be a promising therapeutic strategy for personalized HCC treatment.

Microbiota transplantation reveals beneficial impact of berberine on hepatotoxicity by improving gut homeostasis.

Berberine has been shown to reduce acute liver injury although the underlying mechanism is not fully understood. Because of the anatomic connection, the liver is constantly exposed to gut-derived bacterial products and metabolites. In this study, we showed that berberine has beneficial effects on both hepatotoxicity and intestinal damage in a rat model of chronic or acute liver injury. Microbiota transplantation from the rats with chronic hepatotoxicity could aggravate acute hepatotoxicity in mice treated with diethylnitrosamine (DEN). In rat models with gut homeostasis disruption induced by penicillin or dextran sulfate sodium (DSS), their fecal microbiota could also cause an enhanced hepatotoxicity of recipient mice. When treated with berberine, the DSS-induced enteric dysbacteriosis could be mitigated and their fecal bacteria were able to reduce acute hepatotoxicity in recipient mice. This study indicates that berberine could improve intestinal dysbacteriosis, which reduces the hepatotoxicity caused by pathological or pharmacological intervention. Fecal microbiota transplantation might be a useful method to directly explore homeostatic alteration in gut microbiota.