Antagonizing adipose tissue-derived exosome miR-103-hepatocyte phosphatase and tensin homolog pathway alleviates autophagy in non-alcoholic steatohepatitis:A trans-cellular crosstalk

BACKGROUND Obesity plays a vital role in the occurrence and development of non-alcoholic steatohepatitis(NASH).However,the underlining mechanism is still unclear,where adipose tissue(AT)derived exosomes may actively participate.MicroRNAs(miRNAs)are commonly secreted from exosomes for cell communication.Though the regulation of miR-103 on insulin sensitivity has been reported,the specific role of AT-derived exosomes miR-103 in NASH is still vague and further investigation may provide novel therapeutic choices.AIM To determine the specific role of AT-derived exosomes miR-103 in developing NASH through various methods.METHODS The expression levels of miR-103 in the AT-derived exosomes and livers were detected and compared between NASH mice and control.The effect of miR-103 on NASH progression was also explored by antagonizing miR-103,including steatosis and inflammation degree changes.The interaction between miR-103 and the autophagy-related gene phosphatase and tensin homolog(PTEN)was confirmed by dual-luciferase reporter assay.The role of the interaction between miR-103 and PTEN on autophagy was verified in NASH-like cells.Finally,the effects of miR-103 from adipose-derived exosomes on NASH and autophagy were analyzed through animal experiments.RESULTS The expression of miR-103 was increased in NASH mice,compared to the control,and inhibition of miR-103 could alleviate NASH.The results of the dual-luciferase reporter assay showed miR-103 could interact with PTEN.MiR-103-anta decreased p-AMPKa,p-mammalian target of rapamycin(mTOR),and p62 but increased the protein levels of PTEN and LC3-II/I and the number of autophagosomes in NASH mice.Similar results were also observed in NASH-like cells,and further experiments showed PTEN silencing inhibited the effect of miR-103-anta.AT derivedexosome miR-103 aggravated NASH and increased the expressions of p-AMPKa,p-mTOR,and p62 but decreased the protein levels of PTEN and LC3-II/I and the number of autophagosomes in mice.CONCLUSION AT derived-exosome increased the levels of miR-103 in the liver,and miR-103 aggravated NASH.Mechanically,miR-103 could interact with PTEN and inhibit autophagy.

Nerve growth factor pretreatment against glutamate-induced hippocampal neuronal injury Action mechanism of phosphatase and tensin homologue deleted on chromosome 10

BACKGROUND： Nerve growth factor （NGF） attenuates glutamate-induced injury to hippocampal neurons, and the human tumor suppressor gene phosphatase and tensin homologue deleted on chromosome 10 （PTEN） promotes neuronal apoptosis. However, effects of PTEN in NGF-mediated neuroprotection against glutamate excitotoxicity remain poorly understood. OBJECTIVE： To investigate the relationship between NGF inhibition of glutamate-induced injury and PTEN. DESIGN, TIME AND SE＇I＇rlNG： The randomized, controlled, in vitro study was performed at the Department of Pathophysiology, Medical School of Nantong University, China from October 2007 to March 2008. MATERIALS： Glutamate, NGF, 4, 6-diamidino-2-phenyl-indolediacetate, 3-[4, 5-dimethylthiazol-2-yl]- 2, 5-diphenyl tetrazoliumbromide （M-I-F）, and lactate dehydrogenase kit （Sigma, USA）, fluorescence microscope and inverted phase contrast microscope （Olympus, Japan） were used in this study. METHODS： Hippocampal neurons were obtained from newborn （〈 24 hours） Sprague Dawley rats and cultured for 7 days. The control group was not treated with any intervention factor, the glutamate group was treated with glutamate （0.2 mmol/L）, and NGF groups were treated with NGF （10, 50, 100, and 200 μg/L, respectively） prior to glutamate treatment. MAIN OUTCOME MEASURES： The MTT and lactate dehydrogenase assays were applied to evaluate viability of hippocampal neurons. Morphological changes in hippocampal neurons were observed using an inverted phase-contrast microscope, and neuronal apoptosis was detected by 4, 6-diamidino-2- phenyl-indolediacetate staining. PTEN mRNA and protein expression were measured by reverse transcription-polymerase chain reaction and Western blot analysis, respectively. RESULTS： Glutamate （0.2 mmol/L） induced significantly decreased neuronal viability and greater lactate dehydrogenase efflux compared with the control group （P 〈 0.01）. However, compared with the glutamate group, cell viability significantly increased and lactate dehydrogenase efflux decreased in the NGF group with increasing NGF concentrations （P 〈 0.05 or P 〈 0.01）. The apoptotic ratio and PTEN mRNA and protein expression decreased in the NGF group compared with the glutamate group （P 〈 0.01）. CONCLUSION： Pretreatment with NGF exerted neuroprotective effects against glutamate-induced injury, partially through inhibition of PTEN expression and neuronal apoptosis.

Expression of phosphatase and tensin homolog deleted on chromosome ten in liver of athymic mice with hepatocellular carcinoma and the effect of Fuzheng Jiedu Decoction

AIM： To explore the expression of phosphatase and tensin homolog deleted on chromosome ten （PTEN） in liver of athymic mice with hepatocellular carcinoma （HCC） and the effect of Fuzheng Jiedu Decoction （FJD）. METHODS： Forty eight male BALB/c athymic mice models were built by Bel-7402 with an indirect method. After 24 h of postoperation, the 48 athymic mice were distributed randomly into 4 groups： A, B, C, D, each group had 12 athymic mice. Group A were were treated by intragastric administration with FT207 （Tegafur） for 4 wk. Group B, C and D were treated by intragastric administration with FJD （complex prescription of Chinese crude drug） that had been delegated into 3 kinds of density as the low, middle, and high for 4 wk. At last, athymic mice were put to death, live time, volume of tumors, exponent of tumors and the tumor metastasis in livers were observed; and PTEN was detected in hepatic tissue, latero-cancer tissue and cancer tissue by immunohistochemistry. RESULTS： Four weeks later, the total survival rate in treatment group （A ＋ B ＋ C） was 50% and higher than the control group （0%） treated by FT207, （P 〈 0.01）. The survival rate in group A, B, C was higher than in group D, and except group A with D, there was significant differentces （Fisher＇s Exact Test P = 0.05 or 0.01）. And no differences were observed between the treatment groups and the control group in volume of tumors and exponent of tumors （P 〉 0.05）. Tumor metastasis in livers of the treatment group was less than the controls （Fisher＇s Exact Test, P = 0.021）. The result of immunohistochemistry showed that the intensity of PTEN in latero-cancer tissue was the highest, and then the hepatic tissue, the lowest was cancer tissue （Kruskal- Wallis test, X^2 = 60.67, P = 0.000）. It also showed that the intensity of PTEN in treatment groups （A, B, C） was higher than the control group （D） （F = 5.90, P = 0.002 in hepatic tissue and F = 15.99, P = 0.000 in latero-cancer tissue and X^2 = 26.08, P = 0.000 in cancer tissue）, and group B is the highest in the treatment groups （P 〈 0.05, r = 0.01. respectively）. However, there was no significant statistic difference between group A and group C （P 〉 0.05）. CONCLUSION： FJD can prolong the survival time and decrease tumor metastasis in livers of these experimental mice. Mechanisms of FJD healing HCC may partially be explained by enhancing the expression of PTEN in liver.

Is NEDD4-1 a negative regulator of phosphatase and tensin homolog in gastric carcinogenesis?

The expression of phosphatase and tensin homolog (PTEN ), a tumor suppressor gene, is frequently downregulated in gastric carcinomas due to mutation, loss of heterozygosity, and promoter hypermethylation. However, it is unknown if additional mechanisms may account for the down-regulation of PTEN expression. While neuronal precursor cell-expressed developmentally down-regulated 4-1 (NEDD4-1) is believed to be a potential dual regulator of PTEN, there are conflicting reports regarding their interaction. To gain further insight into the role of NEDD4-1 and its association with PTEN in gastric carcinoma development, we measured the protein expression of NEDD4-1 and PTEN in gastric mucosae with various pathological lesions and found that NEDD4-1 increased from normal gastric mucosa to intestinal metaplasia and decreased from dysplasia to gastric carcinoma. These changes did not correlate with PTEN expression changes during gastric carcinogenesis. Moreover, we found similar results in protein levels in the primary tumors and adjacent non-tumorous tissues. These results differ from a previous report showing that expression of NEDD4-1 is up-regulated in gastric carcinomas, and show a more complex pattern of NEDD4-1 gene expression during gastric carcinogenesis.

phosphatase and tensin homolog is a differential diagnostic marker between nonalcoholic and alcoholic fatty liver disease

AIM: To investigate the protein expression of phosphatase and tensin homolog (PTEN) in human liver biopsies of patients with alcoholic and non-alcoholic liver disease.METHODS: PTEN protein expression was assessed by immunohistochemistry in formalin-fixed, paraffin-embedded liver sections of patients with non-alcoholic fatty liver disease (NAFLD) (n = 44) or alcoholic liver disease (ALD) (n = 25). Liver resections obtained from 3 healthy subjects candidate for partial liver donation served as controls. Histological evaluations were performed by two experienced pathologists, and diagnoses established based on international criteria. The intensity of the PTEN staining in nuclei was compared between steatotic and non-steatotic areas of each liver fragment analyzed. For each liver specimen, the antibody-stained sections were examined and scored blindly by three independent observers, who were unaware of the patients’ clinical history.RESULTS: In healthy individuals, PTEN immunostaining was intense in both the cytoplasm and nuclei of all hepatocytes. However, PTEN was strongly downregulated in both the nucleus and the cytoplasm of hepatocytes from steatotic areas in patients with NAFLD, independently of the disease stage. In contrast, no changes in PTEN protein expression were observed in patients with ALD, regardless of the presence of steatosis or the stage of the disease. The degree of PTEN downregulation in hepatocytes of patients with NAFLD correlated with the percentage of steatosis (r = 0.3061, P = 0.0459) and the BMI (r = 0.4268, P = 0.0043). Hovewer, in patients with ALD, PTEN expression was not correlated with the percentage of steatosis with or without obesity as a confounding factor (P = 0.5574). Finally, PTEN expression level in steatotic areas of ALD patients was significantly different from that seen in steatotic areas of NAFLD patients (P < 0.0001).CONCLUSION: PTEN protein expression is downregulated early in NAFLD, but not in ALD. PTEN immunohistochemical detection could help in the differential diagnosis of NAFLD and ALD.

Rapid construction of phosphatase and tensin homolog-deleted on chromosome ten gene recombinant adenovirus using the AdEasy system

Recent studies have shown that phosphatase and tensin homolog-deleted on chromosome ten （PTEN） gene plays an important role in ischemic brain damage and synaptic plasticity. The AdEasy system, which has been widely used, greatly simplifies preparation of recombinant adenovirus. Therefore, recombinant defective adenovirus vector carrying human PTEN tumor suppressor gene （Ad-PTEN） was constructed using the AdEasy-1 system and was transfected into HEK293 cells for packaging and amplification. Infection efficiency and expression intensity were observed in primary cultured rat hippocampal neurons infected with Ad-PTEN in vitro. Results revealed a cytopathic effect in green fluorescent protein expression, which increased with prolonged time. After three cycles of amplification, the adenovirus titer was increased to an adequate titer for infecting hippocampal neurons. The entire process typically requires 4-5 weeks for completion. Results suggested that recombinant defective adenovirus vector carrying the PTEN gene was successfully and rapidly constructed using the AdEasy system.

Dual regulatory role for phosphatase and tensin homolog in specification of intestinal endocrine cell subtypes

AIM:To investigate the impact of phosphatase and tensin homolog(Pten) in the specification of intestinal enteroendocrine subpopulations.METHODS:Using the Cre/loxP system,a mouse with conditional intestinal epithelial Pten deficiency was generated.Pten mutant mice and controls were sacrificed and small intestines collected for immunofluorescence and quantitative real-time polymerase chain reaction.Blood was collected on 16 h fasted mice by cardiac puncture.Enzyme-linked immunosorbent assay was used to measure blood circulating ghrelin,somatostatin(SST) and glucose-dependent insulinotropic peptide(GIP) levels.RESULTS:Results show an unexpected dual regulatory role for epithelial Pten signalling in the specification/differentiation of enteroendocrine cell subpopulations in the small intestine.Our data indicate that Pten positively regulates chromogranin A(CgA) expressing subpopulations,including cells expressing secretin,ghrelin,gastrin and cholecystokinin(CCK).In contrast,Pten negatively regulates the enteroendocrine subtype specification of non-expressing CgA cells such as GIP and SST expressing cells.CONCLUSION:The present results demonstrate that Pten signalling favours the enteroendocrine progenitor to specify into cells expressing CgA including those producing CCK,gastrin and ghrelin.

Phosphatase and tensin homolog expression related to cetuximab effects in colorectal cancer patients: A meta-analysis

AIM: To investigate the correlation between expression of phosphatase and tensin homolog (PTEN) and cetuximab effects in colorectal cancer. METHODS: We searched PubMed, EMBASE and ASCO to identify eligible studies. Finally, 8 randomized control studies were included in the meta-analysis. STATA 10.0 Software was used to investigate heterogeneity among individual studies and to summarize all the studies. Risk ratios (RRs) and hazard ratios (HRs) with 95% confidence intervals (CIs) were used to assess the strength of the association. RESULTS: Compared with 20 of 266 patients with loss of PTEN, 206 of 496 patients with intact PTEN protein expression had a better objective response rate to cetuximab-based therapy (RR, 4.75; 95% CI, 2.59-8.72; P < 0.001). PTEN positivity was associated with better progression-free survival (PFS) (HR, 0.675; 95% CI, 0.473-0.964; P = 0.031) but not with better overall survival (OS) (HR, 0.608; 95% CI, 0.411-0.899; P = 0.013). In patients with KRAS wild-type status, PTEN positivity did not predict a longer PFS or OS (PFS: HR, 0.707; 95% CI, 0.440-1.138; P = 0.154; OS: HR, 0.943; 95% CI, 0.646-1.377; P = 0.761). CONCLUSION: Expression of PTEN is related to the effect of cetuximab in colorectal cancer patients and should be considered in treatment with cetuximab.

Phosphatase and tensin homology deleted in chromosome 10,hypoxia-inducible factor-1 alpha gene expression in colorectal adenoma and adenocarcinoma and their relation to vascular endothelial growth factor protein expression

To examine phosphatase and tensin homology deleted in chromosome 10 (PTEN),hypoxia-inducible factor-1 alpha (HIF-1 alpha) gene expressions and their relation to vascular endothelial growth factor(VEGF) protein expression in the patients with human colorectal adenomas and adenocarcinomas.Methods The expression of PTEN,HIF-1 alpha gene was detected by using in situ hybridization,and the VEGF expression levels by immunohistochemistry in colorectal adenomas and primary colorectal adenocarcinoma.Results Strong expression of HIF-1 alpha was detectable in the majority of colorectal dadenocarcinoma,particularly surrounding areas of necrosis in adenocarcinoma.PTEN,HIF-1 alpha mRNA and VEGF protein were positive in 51.6%,67.7% and 59.7% respectively in 62 cases of adenocarcinomas,and 77.8%,44.4% and 33.3% respectively in 18 cases of adenomas.The positive rate of VEGF was higher in the patients with colorectal adenocarcinomas than that in those with adenomas,whereas that of PTEN mRNA was contrary.HIF-1 mRNA expression was correlated significantly with lymph node metastasis,liver metastasis,Duke’s stage and recurrence.During colorectal tumor progression,the expression of HIF-1 alpha mRNA was positively correlated with the VEGF protein expression (χ2= 4.751 ,P<0.05),but negatively with the PTEN mRNA expression(χ2=21.84,P<0.01).Conclusion The absence or low expression of PTEN and the increased levels of HIF-1α and VEGF may paly an important role in carcinogenesis and progression of colorectal carcinoma.These results suggest that VEGF upregulated by HIF-1 alpha gene may be involved in angiogenesis of colorectal adenocarcinoma.4 refs,1 tab.

Genome-wide CRISPR screening identifies critical role of phosphatase and tensin homologous (PTEN) in sensitivity of acute myeloid leukemia to chemotherapy

Although significant progress has been made in the development of novel targeted drugs for the treatment of acute myeloid leukemia(AML)in recent years,chemotherapy still remains the mainstay of treatment and the overall survival is poor in most patients.Here,we demonstrated the antileukemia activity of a novel small molecular compound NL101,which is formed through the modification on bendamustine with a suberanilohydroxamic acid(SAHA)radical.NL101 suppresses the proliferation of myeloid malignancy cells and primary AML cells.It induces DNA damage and caspase 3-mediated apoptosis.A genome-wide clustered regularly interspaced short palindromic repeats(CRISPR)library screen revealed that phosphatase and tensin homologous(PTEN)gene is critical for the regulation of cell survival upon NL101 treatment.The knockout or inhibition of PTEN significantly reduced NL101-induced apoptosis in AML and myelodysplastic syndrome(MDS)cells,accompanied by the activation of protein kinase B(AKT)signaling pathway.The inhibition of mammalian target of rapamycin(mTOR)by rapamycin enhanced the sensitivity of AML cells to NL101-induced cell death.These findings uncover PTEN protein expression as a major determinant of chemosensitivity to NL101 and provide a novel strategy to treat AML with the combination of NL101 and rapamycin.

Hepatoprotective effects of Xiaoyao San formula on hepatic steatosis and inflammation via regulating the sex hormones metabolism

BACKGROUND The modified Xiaoyao San(MXS)formula is an adjuvant drug recommended by the National Health Commission of China for the treatment of liver cancer,which has the effect of preventing postoperative recurrence and metastasis of hepatocellular carcinoma and prolonging patient survival.However,the molecular mechanisms underlying that remain unclear.AIM To investigate the role and mechanisms of MXS in ameliorating hepatic injury,steatosis and inflammation.METHODS A choline-deficient/high-fat diet-induced rat nonalcoholic steatohepatitis(NASH)model was used to examine the effects of MXS on lipid accumulation in primary hepatocytes.Liver tissues were collected for western blotting and immunohisto chemistry(IHC)assays.Lipid accumulation and hepatic fibrosis were detected using oil red staining and Sirius red staining.The serum samples were collected for biochemical assays and NMR-based metabonomics analysis.The inflammation/lipid metabolism-related signaling and regulators in liver tissues were also detected to reveal the molecular mechanisms of MXS against NASH.RESULTS MXS showed a significant decrease in lipid accumulation and inflammatory response in hepatocytes under metabolic stress.The western blotting and IHC results indicated that MXS activated AMPK pathway but inhibited the expression of key regulators related to lipid accumulation,inflammation and hepatic fibrosis in the pathogenesis of NASH.The metabonomics analysis systemically indicated that the arachidonic acid metabolism and steroid hormone synthesis are the two main target metabolic pathways for MXS to ameliorate liver inflammation and hepatic steatosis.Mechanistically,we found that MXS protected against NASH by attenuating the sex hormone-related metabolism,especially the metabolism of male hormones.CONCLUSION MXS ameliorates inflammation and hepatic steatosis of NASH by inhibiting the metabolism of male hormones.Targeting male hormone related metabolic pathways may be the potential therapeutic approach for NASH.

Nuclear miR-665 aggravates heart failure via suppressing phosphatase and tensin homolog transcription

Although numerous miRNAs have been discovered,their functions in the different subcellular organelles have remained obscure.In this study,we found that miR-665 was enriched in the nucleus of cardiomyocytes,and then investigated the underlying role of nuclear miR-665 in heart failure.RNA fluorescence in situ hybridization assays in human heart tissue sections and primary cardiomyocytes showed that miR-665 was localized in the nucleus of cardiomyocytes.Increased expression of nuclear miR-665 was observed not only in the cardiomyocytes isolated from the heart of mice treated in vivo by transverse aortic constriction(TAC),but also in phenylephrine(PE)-treated cultured cardiomyocytes in vitro.To further explore the role of miR-665 in heart failure,a type 9 recombinant adeno-associated virus(rAAV)system was employed to manipulate the expression of miR-665 in mice.Overexpression of miR-665 aggravated TAC-induced cardiac dysfunction,while down-expression of miR-665 showed opposite effects.Bioinformatic prediction and biological validation confirmed that the PTEN(phosphatase and tensin homolog)gene was one of the targets of miR-665 in the nucleus.Furthermore,restoring PTEN expression significantly eliminated the destructive effects of miR-665 over-expression in TAC-induced cardiac dysfunction.Our data showed that nuclear miR-665 aggravates heart failure via inhibiting PTEN expression,which provided a therapeutic approach for heart failure.

Phosphatase and Tensin Homologue Genetic Polymorphisms and their Interactions with Viral Mutations on the Risk of Hepatocellular Carcinoma

Background： Chronic hepatitis B virus （HBV） infection is the major cause of hepatocellular carcinoma （HCC）. Some HBV mutants and dysregulation of phosphatase and tensin homolog （PTEN） may promote the development of HCC synergistically. We aimed to test the effects of PTEN genetic polymorphisms and their interactions with important HBV mutations on the development of HCC in HBV-infected subjects. Methods： Quantitative po[ymerase chain reaction was applied to genotype PTEN polymorphisms （rs1234220, rs2299939, rsl234213） in 1012 healthy controls, 302 natural clearance subjects, and 2011 chronic H BV-infected subjects including 1021 HCC patients. HBV mutations were determined by sequencing. The associations of PTEN polymorphisms and their interactions with HBV mutations with HCC risk were assessed using multivariate logistic regression analysis. Results： Rs1234220 C allele was significantly associated with HCC risk compared to healthy controls （adjusted odds ratio [AOR] = 1.35, 95% confidence interval [CI] = 1,07-1.69） and HCC-free HBV-infected subjects （AOR = 1.27, 95% CI = 1.01-1 .57）. rsl234220 C allele was significantly associated with increased frequencies of HCC-risk A 1652G, C 1673T, and C 1730G mutations in genotype B H BV-in fected subjects. Rs2299939 GT genotype was inversely associated with HCC risk in HBV-infected patients （AOR 0.75, 95% CI 0.62-0.92）. The interaction of rs2299939 variant genotypes （GT＋TT） with A3054T mutation significantly increased HCC risk （AOR = 2.41, 95% CI = 1.08-5.35）; whereas its interaction with C3116T mutation significantly reduced HCC risk （AOR = 0.34, 95% CI 0.18-0.66）. These significant effects were only evident in males alter stratification. Conclusions： PTEN polymorphisms and their interactions with HBV mutations may contribute to hepatocarcinogenesis in males. The host-virus interactions are important in identifying HBV-infected subjects who are more likely to develop HCC.

MiR-106b-5p Inhibits Tumor Necrosis Factor-α-induced Apoptosis by Targeting Phosphatase and Tensin Homolog Deleted on Chromosome 10 in Vascular Endothelial Cells

Background： Apoptosis of endothelial cells （ECs） plays a key role in the development of atherosclerosis and there are also evidence indicated that phosphatase and tensin homolog deleted on chromosome 10 （PTEN） is a viable target in therapeutic approaches to prevent vascular ECs apoptosis. Aberrant miR-106b-5p expression has been reported in the plasma of patients with unstable atherosclerotic plaques. However, the role and underlying mechanism of miR-106-5p in the genesis of atherosclerosis have not been addressed. In this study, we explored the anti-apoptotic role of miR-106-5p by regulating PTEN expression in vascular ECs. Methods： Real-time reverse transcription polymerase chain reaction （RT-PCR） was performed to detect the expression levels of miR-106b-5p in human atherosclerotic plaques and normal vascular tissues. Human umbilical vein endothelial cells （HUVEC） were transfected with miR-106b-5p mimic or negative control mimic, and apoptosis was induced by serum starvation and tumor necrosis factor-α （TN F-α） treat. Western blotting and real-time RT-PCR experiments were used to detect PTEN expression levels and TN F-α-induced apoptosis was evaluated by the activation of caspase-3 and cell DNA fragmentation levels in HUVEC. Results： The expression ofmiR-106b-5p was significantly downregulated in plaques than in normal vascular tissues. TNF-α significantly downregulated miR-106b-5p expression levels and upregulated activation of caspase-3 and cell DNA fragmentation levels in HUVEC. Overexpression ofmiR-106b-5p with miR-106b-5p mimic inhibited PTEN expression and TNF-α-induced apoptosis in HUVEC. Luciferase reporter assays confirmed that miR-106b-5p binds to PTEN mRNA 3＇ untranslated region site, Conclusion： MiR-106b-5p could inhibit the expression of PTEN in vascular ECs, which could block TNF-α-induced activation of caspase-3, thus prevent ECs apoptosis in atherosclerosis diseases.

Suppression of hepatic steatosis in non-alcoholic steatohepatitis model by modified Xiaoyao San formula:Evidence,mechanisms and perspective

In this letter,we comment on a recent publication by Mei et al,in the World Journal of Hepatology,investigating the hepatoprotective effects of the modified Xiaoyao San(MXS)formula in a male rat model of non-alcoholic steatohepatitis(NASH).The authors found that MXS treatment mitigated hepatic steatosis and inflam-mation in the NASH model,as evidenced by the reduction in lipid droplets(LDs),fibrosis markers and lipogenic factors.Interestingly,these hepatoprotective effects were associated with androgen upregulation(based on metabolomics analysis of male steroid hormone metabolites),adenosine 5’-monophosphate-activated protein kinase(AMPK)activation,and restoration of phosphatase and tensin homolog(PTEN)expression.However,the authors did not clearly discuss the relationships between MXS-induced hepatic steatosis reduction in the NASH model,and androgen upregulation,AMPK activation,and restoration of PTEN expression.This editorial emphasizes the reported mechanisms and explains how they act or interact with each other to reduce hepatic steatosis and inflammation in the NASH model.As a perspective,we propose additional mechanisms(such as autophagy/lipophagy activation in hepatocytes)for the clearance of LDs and suppression of hepatic steatosis by MXS in the NASH model.A proper understanding of the mechanisms of MXS-induced reduction of hepatic steatosis might help in the treatment of NASH and related diseases.

Micro RNA-21 promotes phosphatase gene and protein kinase B/phosphatidylinositol 3-kinase expression in colorectal cancer

AIM: To explore the regulatory mechanism of the target gene of micro RNA-21(mi R-21), phosphatase gene(p TEN), and its downstream proteins, protein kinase B(AKT) and phosphatidylinositol 3-kinase(p I3K), in colorectal cancer(CRC) cells. METHODS: Quantitative real-time p CR(q RT-p CR) and Western blot were used to detect the expression levels of mi R-21 and p TEN in HCT116, HT29, Colo32 and SW480 CRC cell lines. Also, the expression levels of p TEN m RNA and its downstream proteins AKT and p I3 K in HCT116 cells after downregulating mi R-21 were investigated. RESULTS: Comparing the mi R-21 expression in CRC cells, the expression levels of mi R-21 were highest in HCT116 cells, and the expression levels of mi R-21 were lowest in SW480 cells. In comparing mi R-21 and p TEN expression in CRC cells, we found that the protein expression levels of mi R-21 and p TEN were inversely correlated(p < 0.05); when mi R-21 expression was reduced, m RNA expression levels of p TEN did not significantly change(p > 0.05), but the expression levels of its protein significantly increased(p < 0.05). In comparing the levels of p TEN protein and downstream AKT and p I3 K in HCT116 cells after downregulation of mi R-21 expression, the levels of AKT and p I3 K protein expression significantly decreased(p < 0.05). CONCLUSION: p TEN is one of the direct target genesof mi R-21. Thus, phosphatase gene and its downstream AKT and p I3 K expression levels can be regulated by regulating the expression levels of mi R-21, which in turn regulates the development of CRC.

PTEN in liver diseases and cancer

The phosphoinositide 3-kinase (PI3K)/phosphatase and tensin homolog (PTEN)/Akt axis is a key signal transduction node that regulates crucial cellular functions, including insulin and other growth factors signaling, lipid and glucose metabolism, as well as cell survival and apoptosis. In this pathway, PTEN acts as a phosphoinositide phosphatase, which terminates PI3Kpropagated signaling by dephosphorylating PtdIns(3,4)P2 and PtdIns(3,4,5)P3. However, the role of PTEN does not appear to be restricted only to PI3K signaling antagonism, and new functions have been recently discovered for this protein. In addition to the well-established role of PTEN as a tumor suppressor, increasing evidence now suggests that a dysregulated PTEN expression and/or activity is also linked to the development of several hepatic pathologies. Dysregulated PTEN expression/activity is observed with obesity, insulin resistance, diabetes, hepatitis B virus/hepatitis C virus infections, and abusive alcohol consumption, whereas mutations/deletions have also been associated with the occurrence of hepatocellular carcinoma. Thus, it appears that alterations of PTEN expression and activity in hepatocytes are common and recurrent molecular events associated with liver disorders of various etiologies. These recent f indings suggest that PTEN might represent a potential common therapeutic target for a number of liver pathologies.

Increased susceptibility of aging gastric mucosa to injury:The mechanisms and clinical implications

This review updates the current views on aging gastric mucosa and the mechanisms of its increased susceptibility to injury. Experimental and clinical studies indicate that gastric mucosa of aging individuals-&#x0201c;aging gastropathy&#x0201d;-has prominent structural and functional abnormalities vs young gastric mucosa. Some of these abnormalities include a partial atrophy of gastric glands, impaired mucosal defense (reduced bicarbonate and prostaglandin generation, decreased sensory innervation), increased susceptibility to injury by a variety of damaging agents such as ethanol, aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs), impaired healing of injury and reduced therapeutic efficacy of ulcer-healing drugs. Detailed analysis of the above changes indicates that the following events occur in aging gastric mucosa: reduced mucosal blood flow and impaired oxygen delivery cause hypoxia, which leads to activation of the early growth response-1 (egr-1) transcription factor. Activation of egr-1, in turn, upregulates the dual specificity phosphatase, phosphatase and tensin homologue deleted on chromosome ten (PTEN) resulting in activation of pro-apoptotic caspase-3 and caspase-9 and reduced expression of the anti-apoptosis protein, survivin. The imbalance between pro- and anti-apoptosis mediators results in increased apoptosis and increased susceptibility to injury. This paradigm has human relevance since increased expression of PTEN and reduced expression of survivin were demonstrated in gastric mucosa of aging individuals. Other potential mechanisms operating in aging gastric mucosa include reduced telomerase activity, increase in replicative cellular senescence, and reduced expression of vascular endothelial growth factor and importin-&#x003b1;-a nuclear transport protein essential for transport of transcription factors to nucleus. Aging gastropathy is an important and clinically relevant issue because of: (1) an aging world population due to prolonged life span; (2) older patients have much greater risk of gastroduodenal ulcers and gastrointestinal complications (e.g., NSAIDs-induced gastric injury) than younger patients; and (3) increased susceptibility of aging gastric mucosa to injury can be potentially reduced or reversed pharmacologically.

PTEN and Ki67 expression is associated with clinicopathologic features of non-small cell lung cancer

Phosphatase and tensin homolog deleted on chromosome 10（PTEN） and the proliferating antigen Ki67 have been widely studied in several tumors.However,their role as indicator in non-small cell lung cancer（NSCLC）remains unknown.Here,we investigated the expression of PTEN and Ki67 in NSCLC tissues and paired normal lung tissues to identify whether these proteins are associated with lung cancer development and survival.Immunohistochemistry for PTEN and Ki67 was performed on 67 lung cancer tissues and 41 paired adjacent normal lung tissues to detect the expression of these two proteins.The expression of PTEN in NSCLC tissues（32.8%） was significantly lower than that in normal tissues（82.9%,P 〈 0.05）.In contrast,the expression of Ki67 in NSCLC tissues（76.1%） was significantly higher than that in normal tissues（27.3%,P 〈 0.05）.Expression of both PTEN and Ki67 were strongly associated with tumor histology,clinical stage,lymph node metastasis,differentiation and4-year postoperative survival rate（P 〈 0.05）.However,PTEN expression was negatively correlated with Ki67 expression（r =-0.279,P 〈 0.05）.In conclusion,low PTEN expression and Ki67 overexpression are associated with malignant invasion and lymph node metastasis of NSCLC.These proteins may serve as diagnostic and prognostic biomarkers of NSCLC.

MiR-200a and miR-200b target PTEN to regulate the endometrial cancer cell growth in vitro

Objective:To study whether miR-200a and miR-200b target PTEN gene expression to regulate the endometrial cancer cell growth in vitro. Methods:Endometrial cancer cells ECC-1 were cultured and transfected with the miR-200a and miR-200b mimics and inhibitors as well as the negative control mimics and inhibitors,and then the cell proliferation activity as well as the expression of PTEN and downstream genes in cells was determined; after transfection of miR-200a and miR-200b mimics as well as PTEN-3'UTR luciferase report gene plasmids,the fluorescence activity of luciferase reporter gene was determined. Results:12 h,24 h and 48 h after transfection,the cell proliferation activity of miR-200a mimics group and miR-200b mimics group were significantly higher than those of NC mimics group while the cell proliferation activity of mi R-200 a inhibitor group and miR-200b inhibitor group were significantly lower than those of NC inhibitor group; 48 h after transfection,PTEN expression in cells and PTEN-3'UTR luciferase reporter gene fluorescence activity of miR-200 a mimics group and miR-200b mimics group were significantly lower than those of NC mimics group while p-PI3K and p-Akt expression were significantly higher than those of NC mimics group; PTEN expression in cells and PTEN-3'UTR luciferase reporter gene fluorescence activity of miR-200 inhibitor group and miR-200b inhibitor group were significantly higher than those of NC inhibitor group while p-PI3K and p-Akt expression were significantly lower than those of NC inhibitor group. Conclusion:miR-200 a and miR-200b can promote the endometrial cancer cell growth in vitro by targeted inhibition of PTEN gene expression.