Hepatic prohibitin 1 and methionine adenosyltransferase α1 defend against primary and secondary liver cancer metastasis.

BACKGROUND & AIMS: The liver is a common site of cancer metastasis, most commonly from colorectal cancer, and primary liver cancers that have metastasized are associated with poor outcomes. The underlying mechanisms by which the liver defends against these processes are largely unknown. Prohibitin 1 (PHB1) and methionine adenosyltransferase 1A (MAT1A) are highly expressed in the liver. They positively regulate each other and their deletion results in primary liver cancer. Here we investigated their roles in primary and secondary liver cancer metastasis. METHODS: We identified common target genes of PHB1 and MAT1A using a metastasis array, and measured promoter activity and transcription factor binding using luciferase reporter assays and chromatin immunoprecipitation, respectively. We examined how PHB1 or MAT1A loss promotes liver cancer metastasis and whether their loss sensitizes to colorectal liver metastasis (CRLM). RESULTS: Matrix metalloproteinase-7 (MMP-7) is a common target of MAT1A and PHB1 and its induction is responsible for increased migration and invasion when MAT1A or PHB1 is silenced. Mechanistically, PHB1 and MAT1A negatively regulate MMP7 promoter activity via an AP-1 site by repressing the MAFG-FOSB complex. Loss of MAT1A or PHB1 also increased MMP-7 in extracellular vesicles, which were internalized by colon and pancreatic cancer cells to enhance their oncogenicity. Low hepatic MAT1A or PHB1 expression sensitized to CRLM, but not if endogenous hepatic MMP-7 was knocked down first, which lowered CD4+ T cells while increasing CD8+ T cells in the tumor microenvironment. Hepatocytes co-cultured with colorectal cancer cells express less MAT1A/PHB1 but more MMP-7. Consistently, CRLM raised distant hepatocytes' MMP-7 expression in mice and humans. CONCLUSION: We have identified a PHB1/MAT1A-MAFG/FOSB-MMP-7 axis that controls primary liver cancer metastasis and sensitization to CRLM. IMPACT AND IMPLICATIONS: Primary and secondary liver cancer metastasis is associated with poor outcomes but whether the liver has underlying defense mechanism(s) against metastasis is unknown. Here we examined the hypothesis that hepatic prohibitin 1 (PHB1) and methionine adenosyltransferase 1A (MAT1A) cooperate to defend the liver against metastasis. Our studies found PHB1 and MAT1A form a complex that suppresses matrix metalloproteinase-7 (MMP-7) at the transcriptional level and loss of either PHB1 or MAT1A sensitizes the liver to metastasis via MMP-7 induction. Strategies that target the PHB1/MAT1A-MMP-7 axis may be a promising approach for the treatment of primary and secondary liver cancer metastasis.

Epicardial adipose tissue in patients with chronic obstructive pulmonary disease: systematic review with meta­analysis and trial sequential analysis.

BACKGROUND: Limited data suggest that chronic obstructive pulmonary disease (COPD) patients have pathologic elevated epicardial adipose tissue (EAT), which is splanchnic fat tissue with anti-inflammatory properties and regulating free fatty acids functions. Therefore, there is a need for meta-analysis to explore the relationship between EAT and COPD. METHODS: Online databases were systematically searched for studies about EAT in COPD patients published up to October 5th, 2022. The EAT data of the COPD patient group and the control group were included. Trial sequential analysis (TSA) and meta-analysis were applied to assess the difference in EAT between patients with and without COPD. TSA software and Stata 12.0 were used in all statistical analyses. RESULTS: The final analysis included 5 studies (n = 596 patients). COPD patients had significantly more EAT than control subjects (SMD: 0.0.802; 95% CI: 0.231, 1.372; P = 0.006; TSA-adjusted 95% CI 1.20, 1.80; P < 0.0001). And higher CRP levels in COPD patients than non-COPD patients, whereas triglycerides and LDL were not significantly different between patients with and without COPD. CONCLUSION: EAT is abnormally elevated in COPD patients, which may be related to systemic inflammatory responses in COPD. PROSPERO NUMBER: CRD42021228273.

Effect of Argatroban Plus Intravenous Alteplase vs Intravenous Alteplase Alone on Neurologic Function in Patients With Acute Ischemic Stroke: The ARAIS Randomized Clinical Trial.

Importance: Previous studies suggested a benefit of argatroban plus alteplase (recombinant tissue-type plasminogen activator) in patients with acute ischemic stroke (AIS). However, robust evidence in trials with large sample sizes is lacking. Objective: To assess the efficacy of argatroban plus alteplase for AIS. Design, Setting, and Participants: This multicenter, open-label, blinded end point randomized clinical trial including 808 patients with AIS was conducted at 50 hospitals in China with enrollment from January 18, 2019, through October 30, 2021, and final follow-up on January 24, 2022. Interventions: Eligible patients were randomly assigned within 4.5 hours of symptom onset to the argatroban plus alteplase group (n = 402), which received intravenous argatroban (100 µg/kg bolus over 3-5 minutes followed by an infusion of 1.0 µg/kg per minute for 48 hours) within 1 hour after alteplase (0.9 mg/kg; maximum dose, 90 mg; 10% administered as 1-minute bolus, remaining infused over 1 hour), or alteplase alone group (n = 415), which received intravenous alteplase alone. Both groups received guideline-based treatments. Main Outcomes and Measures: The primary end point was excellent functional outcome, defined as a modified Rankin Scale score (range, 0 [no symptoms] to 6 [death]) of 0 to 1 at 90 days. All end points had blinded assessment and were analyzed on a full analysis set. Results: Among 817 eligible patients with AIS who were randomized (median [IQR] age, 65 [57-71] years; 238 [29.1%] women; median [IQR] National Institutes of Health Stroke Scale score, 9 [7-12]), 760 (93.0%) completed the trial. At 90 days, 210 of 329 participants (63.8%) in the argatroban plus alteplase group vs 238 of 367 (64.9%) in the alteplase alone group had an excellent functional outcome (risk difference, -1.0% [95% CI, -8.1% to 6.1%]; risk ratio, 0.98 [95% CI, 0.88-1.10]; P = .78). The percentages of participants with symptomatic intracranial hemorrhage, parenchymal hematoma type 2, and major systemic bleeding were 2.1% (8/383), 2.3% (9/383), and 0.3% (1/383), respectively, in the argatroban plus alteplase group and 1.8% (7/397), 2.5% (10/397), and 0.5% (2/397), respectively, in the alteplase alone group. Conclusions and Relevance: Among patients with acute ischemic stroke, treatment with argatroban plus intravenous alteplase compared with alteplase alone did not result in a significantly greater likelihood of excellent functional outcome at 90 days. Trial Registration: ClinicalTrials.gov Identifier: NCT03740958.

A Novel Quinazoline Derivative Prevents and Treats Arsenic-Induced Liver Injury by Regulating the Expression of RecQ Family Helicase.

Arsenic is a carcinogenic metalloid toxicant widely found in the natural environment. Acute or prolonged exposure to arsenic causes a series of damages to the organs, mainly the liver, such as hepatomegaly, liver fibrosis, cirrhosis, and even hepatocellular carcinoma. Therefore, it is imperative to seek drugs to prevent arsenic-induced liver injury. Quinazolines are a class of nitrogen heterocyclic compounds with biological and pharmacological effects in vivo and in vitro. This study was designed to investigate the ameliorating effects of quinazoline derivatives on arsenic-induced liver injury and its molecular mechanism. We investigated the mechanism of the quinazoline derivative KZL-047 in preventing and ameliorating arsenic-induced liver injury in vitro by cell cycle and apoptosis. We performed real-time fluorescence quantitative polymerase chain reaction (qPCR) and Western blotting combined with molecular docking. In vivo, the experiments were performed to investigate the mechanism of KZL-047 in preventing and ameliorating arsenic-induced liver injury using arsenic-infected mice. Physiological and biochemical indices of liver function in mouse serum were measured, histopathological changes in liver tissue were observed, and immunohistochemical staining was used to detect changes in the expression of RecQ-family helicases in mouse liver tissue. The results of in vitro experiments showed that sodium arsenite (SA) inhibited the proliferation of L-02 cells, induced apoptosis, blocked the cell cycle at the G1 phase, and decreased the expression of RecQ family helicase; after KZL-047 treatment in arsenic-induced L-02 cells, the expression of RecQ family helicase was upregulated, and the apoptosis rate was slowed, leading to the restoration of the cell viability level. KZL-047 inhibited arsenic-induced oxidative stress, alleviated oxidative damage and lipid peroxidation in vivo, and ameliorated arsenic toxicity-induced liver injury. KZL-047 restored the expression of RecQ family helicase proteins, which is consistent with the results of in vitro studies. In summary, KZL-047 can be considered a potential candidate for the treatment of arsenic-induced liver injury.

Targeted suppression of gibberellin biosynthetic genes ZmGA20ox3 and ZmGA20ox5 produces a short stature maize ideotype.

Maize is one of the world's most widely cultivated crops. As future demands for maize will continue to rise, fields will face ever more frequent and extreme weather patterns that directly affect crop productivity. Development of environmentally resilient crops with improved standability in the field, like wheat and rice, was enabled by shifting the architecture of plants to a short stature ideotype. However, such architectural change has not been implemented in maize due to the unique interactions between gibberellin (GA) and floral morphology which limited the use of the same type of mutations as in rice and wheat. Here, we report the development of a short stature maize ideotype in commercial hybrid germplasm, which was generated by targeted suppression of the biosynthetic pathway for GA. To accomplish this, we utilized a dominant, miRNA-based construct expressed in a hemizygous state to selectively reduce expression of the ZmGA20ox3 and ZmGA20ox5 genes that control GA biosynthesis primarily in vegetative tissues. Suppression of both genes resulted in the reduction of GA levels leading to inhibition of cell elongation in internodal tissues, which reduced plant height. Expression of the miRNA did not alter GA levels in reproductive tissues, and thus, the reproductive potential of the plants remained unchanged. As a result, we developed a dominant, short-stature maize ideotype that is conducive for the commercial production of hybrid maize. We expect that the new maize ideotype would enable more efficient and more sustainable maize farming for a growing world population.

Reciprocal Regulation Between Forkhead Box M1/NF-κB and Methionine Adenosyltransferase 1A Drives Liver Cancer.

BACKGROUND AND AIMS: Forkhead box M1 (FOXM1) and nuclear factor kappa B (NF-ĸB) are oncogenic drivers in liver cancer that positively regulate each other. We showed that methionine adenosyltransferase 1A (MAT1A) is a tumor suppressor in the liver and inhibits NF-ĸB activity. Here, we examined the interplay between FOXM1/NF-κB and MAT1A in liver cancer. APPROACH AND RESULTS: We examined gene and protein expression, effects on promoter activities and binding of proteins to promoter regions, as well as effects of FOXM1 inhibitors T0901317 (T0) and forkhead domain inhibitory-6 (FDI-6) in vitro and in xenograft and syngeneic models of liver cancer. We found, in both hepatocellular carcinoma and cholangiocarcinoma, that an induction in FOXM1 and NF-κB expression is accompanied by a fall in MATα1 (protein encoded by MAT1A). The Cancer Genome Atlas data set confirmed the inverse correlation between FOXM1 and MAT1A. Interestingly, FOXM1 directly interacts with MATα1 and they negatively regulate each other. In contrast, FOXM1 positively regulates p50 and p65 expression through MATα1, given that the effect is lost in its absence. FOXM1, MATα1, and NF-κB all bind to the FOX binding sites in the FOXM1 and MAT1A promoters. However, binding of FOXM1 and NF-κB repressed MAT1A promoter activity, but activated the FOXM1 promoter. In contrast, binding of MATα1 repressed the FOXM1 promoter. MATα1 also binds and represses the NF-κB element in the presence of p65 or p50. Inhibiting FOXM1 with either T0 or FDI-6 inhibited liver cancer cell growth in vitro and in vivo. However, inhibiting FOXM1 had minimal effects in liver cancer cells that do not express MAT1A. CONCLUSIONS: We have found a crosstalk between FOXM1/NF-κB and MAT1A. Up-regulation in FOXM1 lowers MAT1A, but raises NF-κB, expression, and this is a feed-forward loop that enhances tumorigenesis.

Evaluating effort-reward imbalance among nurses in emergency departments: a cross-sectional study in China.

BACKGROUND: Effort-reward imbalance is an adverse psychological response to working conditions that has several negative effects on nurses. However, there is little research on effort-reward imbalance and its influencing factors among nurses in emergency departments. This study aimed to understand the current situation of effort-reward imbalance and explore its influencing factors among emergency department nurses in China. METHODS: From July to August 2018, a structured online questionnaire survey was conducted among emergency department nurses in China. Data were collected from emergency department nurses employed in hospitals providing pre-hospital care in China. The questionnaire consisted of sociodemographic characteristics, work-related factors and effort-reward imbalance. A descriptive analysis and a binary logistic regression were conducted to explore the effort-reward imbalance and its influencing factors among emergency department nurses. RESULTS: The study involved 17,582 emergency department nurses; notably, the prevalence of effort-reward imbalance was 59.66%. The participating nurses who were males, aged 25 to 34 years, whose educational level was a bachelor degree or above, who had a junior or above title, who had longer years of service, and who had suffered verbal or physical violence in the past year had a higher risk of effort-reward imbalance. Furthermore, the nurses with a high monthly income, who believed that the number of nurses met the department's demand had a lower risk of effort-reward imbalance. CONCLUSIONS: Effort-reward imbalance was prevalent among emergency department nurses in China. Measures such as adjusting the night shift frequency, increasing the number of nurses, raising salaries and reducing workplace violence should be considered to reduce the level of effort-reward imbalance.

The mitochondrial chaperone Prohibitin 1 negatively regulates interleukin-8 in human liver cancers.

Prohibitin 1 (PHB1) is a mitochondrial chaperone whose expression is dysregulated in cancer. In liver cancer, PHB1 acts as a tumor suppressor, but the mechanisms of tumor suppression are incompletely understood. Here we aimed to determine PHB1 target genes to better understand how PHB1 influences liver tumorigenesis. Using RNA-Seq analysis, we found interleukin-8 (IL-8) to be one of the most highly up-regulated genes following PHB1 silencing in HepG2 cells. Induction of IL-8 expression also occurred in multiple liver and nonliver cancer cell lines. We examined samples from 178 patients with hepatocellular carcinoma (HCC) and found that IL-8 mRNA levels were increased, whereas PHB1 mRNA levels were decreased, in the tumors compared with adjacent nontumorous tissues. Notably, HCC patients with high IL-8 expression have significantly reduced survival. An inverse correlation between PHB1 and IL-8 mRNA levels is found in HCCs with reduced PHB1 expression. To understand the molecular basis for these observations, we altered PHB1 levels in liver cancer cells. Overexpression of PHB1 resulted in lowered IL-8 expression and secretion. Silencing PHB1 increased c-Jun N-terminal kinase (JNK) and NF-κB activity, induced nuclear accumulation of c-JUN and p65, and enhanced their binding to the IL-8 promoter containing AP-1 and NF-κB elements. Conditioned medium from PHB1-silenced HepG2 cells increased migration and invasion of parental HepG2 and SK-hep-1 cells, and this was blocked by co-treatment with neutralizing IL-8 antibody. In summary, our findings show that reduced PHB1 expression induces IL-8 transcription by activating NF-κB and AP-1, resulting in enhanced IL-8 expression and release to promote tumorigenesis.

Development and nationwide application of an antibiotic knowledge scale.

Misconceptions about antibiotics among the public can potentially lead to their inappropriate use. Currently, there is no antibiotic knowledge assessment tool to address this issue. This study aimed to develop and validate an antibiotic knowledge scale (AKS) and apply this scale to assess public knowledge about antibiotics in China. An initial 18-item AKS was designed and validated among 1180 people recruited in June 2017. After removing redundant items, the reliability and validity of the AKS were examined. Subsequently, a nationwide survey was conducted, and 12,772 people were recruited using multistage sampling and surveyed using the developed AKS. A logistic regression model was used to identify the factors associated with poor knowledge about antibiotics. The final AKS included two screening items and fifteen knowledge evaluation items. Cronbach's alpha, test-retest reliability, and split-half reliability were 0.91, 0.88, and 0.89, respectively. These knowledge evaluation items were loaded in four distinct factors that explained 70.72% of cumulative variance among respondents. Using the developed AKS to assess public knowledge about antibiotics among 12,772 participants, the mean score on the AKS was 7.25 and 67% of participants had poor antibiotic knowledge, which was associated with male gender, rural residence, lower educational level, poor economic status, living in western China, and lacking education on antibiotics. The AKS demonstrated satisfactory reliability and validity in identifying the population with poor antibiotic knowledge. Importantly, the majority of participants had inadequate knowledge about antibiotics. Thus, it is necessary to conduct interventions focusing on improving public knowledge about antibiotics.

The effects and safety of omega-3 fatty for acute lung injury: a systematic review and meta-analysis.

BACKGROUND: Several randomized controlled trials (RCTs) have compared the treatment of acute lung injury (ALI) with omega-3 fatty, yet the results remained inconsistent. Therefore, we attempted this meta-analysis to analyze the role of omega-3 fatty in the treatment of ALI patients. METHODS: We searched PubMed databases from inception date to October 31, 2019, for RCTs that compared the treatment of ALI with or without omega-3 fatty. Two authors independently screened the studies and extracted data from the published articles. Summary mean differences (MD) with 95% confidence intervals (CI) were calculated for each outcome by fixed- or random-effects model. RESULTS: Six RCTs with a total of 277 patients were identified, of whom 142 patients with omega-3 fatty acid treatment and 135 patients without omega-3 fatty treatment. Omega-3 fatty treatments significantly improve the PaO2 (MD = 13.82, 95% CI 8.55-19.09), PaO2/FiO2 (MD = 33.47, 95% CI 24.22-42.72), total protein (MD = 2.02, 95% CI 0.43-3.62) in ALI patients, and omega-3 fatty acid treatments reduced the duration of mechanical ventilation (MD = - 1.72, 95% CI - 2.84 to - 0.60) and intensive care unit stay (MD = - 1.29, 95% CI - 2.14 to - 0.43) in ALI patients. CONCLUSIONS: Omega-3 fatty can effectively improve the respiratory function and promote the recovery of ALI patients. Future studies focused on the long-term efficacy and safety of omega-3 fatty use for ALI are needed.

Mechanisms of MAFG Dysregulation in Cholestatic Liver Injury and Development of Liver Cancer.

BACKGROUND & AIMS: MAF bZIP transcription factor G (MAFG) is activated by the farnesoid X receptor to repress bile acid synthesis. However, expression of MAFG increases during cholestatic liver injury in mice and in cholangiocarcinomas. MAFG interacts directly with methionine adenosyltransferase α1 (MATα1) and other transcription factors at the E-box element to repress transcription. We studied mechanisms of MAFG up-regulation in cholestatic tissues and the pathways by which S-adenosylmethionine (SAMe) and ursodeoxycholic acid (UDCA) prevent the increase in MAFG expression. We also investigated whether obeticholic acid (OCA), an farnesoid X receptor agonist, affects MAFG expression and how it contributes to tumor growth in mice. METHODS: We obtained 7 human cholangiocarcinoma specimens and adjacent non-tumor tissues from patients that underwent surgical resection in California and 113 hepatocellular carcinoma (HCC) specimens and adjacent non-tumor tissues from China, along with clinical data from patients. Tissues were analyzed by immunohistochemistry. MAT1A, MAT2A, c-MYC, and MAFG were overexpressed or knocked down with small interfering RNAs in MzChA-1, KMCH, Hep3B, and HepG2 cells; some cells were incubated with lithocholic acid (LCA, which causes the same changes in gene expression observed during chronic cholestatic liver injury in mice), SAMe, UDCA (100 µM), or farnesoid X receptor agonists. MAFG expression and promoter activity were measured using real-time polymerase chain reaction, immunoblot, and transient transfection. We performed electrophoretic mobility shift, and chromatin immunoprecipitation assays to study proteins that occupy promoter regions. We studied mice with bile-duct ligation, orthotopic cholangiocarcinomas, cholestasis-induced cholangiocarcinoma, diethylnitrosamine-induced liver tumors, and xenograft tumors. RESULTS: LCA activated expression of MAFG in HepG2 and MzChA-1 cells, which required the activator protein-1, nuclear factor-κB, and E-box sites in the MAFG promoter. LCA reduced expression of MAT1A but increased expression of MAT2A in cells. Overexpression of MAT2A increased activity of the MAFG promoter, whereas knockdown of MAT2A reduced it. MAT1A and MAT2A had opposite effects on the activator protein-1, nuclear factor-κB, and E-box-mediated promoter activity. Expression of MAFG and MAT2A increased, and expression of MAT1A decreased, in diethylnitrosamine-induced liver tumors in mice. SAMe and UDCA had shared and distinct mechanisms of preventing LCA-mediated increased expression of MAFG. OCA increased expression of MAFG, MAT2A, and c-MYC, but reduced expression of MAT1A. Incubation of human liver and biliary cancer cells lines with OCA promoted their proliferation; in nude mice given OCA, xenograft tumors were larger than in mice given vehicle. Levels of MAFG were increased in human HCC and cholangiocarcinoma tissues compared with non-tumor tissues. High levels of MAFG in HCC samples correlated with hepatitis B, vascular invasion, and shorter survival times of patients. CONCLUSIONS: Expression of MAFG increases in cells and tissues with cholestasis, as well as in human cholangiocarcinoma and HCC specimens; high expression levels correlate with tumor progression and reduced survival time. SAMe and UDCA reduce expression of MAFG in response to cholestasis, by shared and distinct mechanisms. OCA induces MAFG expression, cancer cell proliferation, and growth of xenograft tumors in mice.

Prohibitin 1 suppresses liver cancer tumorigenesis in mice and human hepatocellular and cholangiocarcinoma cells.

Prohibitin 1 (PHB1) is best known as a mitochondrial chaperone, and its role in cancer is conflicting. Mice lacking methionine adenosyltransferase α1 (MATα1) have lower PHB1 expression, and we reported that c-MYC interacts directly with both proteins. Furthermore, c-MYC and MATα1 exert opposing effects on liver cancer growth, prompting us to examine the interplay between PHB1, MATα1, and c-MYC and PHB1's role in liver tumorigenesis. We found that PHB1 is highly expressed in normal hepatocytes and bile duct epithelial cells and down-regulated in most human hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA). In HCC and CCA cells, PHB1 expression correlates inversely with growth. PHB1 and MAT1A positively regulate each other's expression, whereas PHB1 negatively regulates the expression of c-MYC, MAFG, and c-MAF. Both PHB1 and MATα1 heterodimerize with MAX, bind to the E-box element, and repress E-box promoter activity. PHB1 promoter contains a repressive E-box element and is occupied mainly by MAX, MNT, and MATα1 in nonmalignant cholangiocytes and noncancerous tissues that switched to c-MYC, c-MAF, and MAFG in cancer cells and human HCC/CCA. All 8-month-old liver-specific Phb1 knockout mice developed HCC, and one developed CCA. Five-month-old Phb1 heterozygotes, but not Phb1 flox mice, developed aberrant bile duct proliferation; and one developed CCA 3.5 months after left and median bile duct ligation. Phb1 heterozygotes had a more profound fall in the expression of glutathione synthetic enzymes and higher hepatic oxidative stress following left and median bile duct ligation. CONCLUSION: We have identified that PHB1, down-regulated in most human HCC and CCA, heterodimerizes with MAX to repress the E-box and positively regulates MAT1A while suppressing c-MYC, MAFG, and c-MAF expression; in mice, reduced PHB1 expression predisposes to the development of cholestasis-induced CCA. (Hepatology 2017;65:1249-1266).

A near-infrared fluorescent sensor with large Stokes shift for rapid and highly selective detection of thiophenols in water samples and living cells.

The development of simple methods with high sensitivity and selectivity to differentiate toxic aromatic thiols (thiophenols) from aliphatic thiols (cysteine, homocysteine, and glutathione) and hydrogen sulfide (H2S) is of great significance. Herein, we report on the fabrication of a novel near-infrared (NIR) fluorescent sensor for rapid and highly selective detection of thiophenols through the photoinduced electron transfer (PET) mechanism. In the presence of the thiophenols, an obvious enhancement of NIR fluorescence at 658 nm could be visualized with the aid of nucleophilic aromatic substitution (SNAr) reaction. The sensor displays large Stokes shift (~ 227 nm), fast response time (< 30 s), high sensitivity (~ 8.3 nM), and good biocompatibility. Moreover, the as-prepared sensor possesses an excellent anti-interference feature even when other possible interferents exist (aliphatic thiols and H2S) and has been successfully utilized for thiophenol detection in both water samples and living cells. Graphical abstract Illustration of the sensor for thiophenol imaging in living cells.

Real-time monitoring of endogenous cysteine levels in living cells using a CD-based ratiometric fluorescent nanoprobe.

A simple and readily available fluorescent probe is needed for the real-time monitoring of endogenous cysteine (Cys) levels in living cells, as such a probe could be used to study the role of Cys in related diseases. Herein, we report the first fluorescent probe based on carbon dots (CDs-FITA) for the selective and ratiometric imaging of endogenous Cys in live cells. In this ratiometric fluorescent probe, a fluorescein derivative (FITA) that recognizes Cys is covalently linked to the surfaces of carbon dots (CDs); employing CDs greatly improves the water solubility of the probe. Acrylate on FITA is selectively cleaved by Cys in aqueous solution under mild conditions, leading to a dramatic increase in the fluorescence from fluorescein. The probe therefore allows the highly selective ratiometric fluorescent detection of Cys even in the presence of various interferents. The as-prepared CDs-FITA showed excellent performance when applied to detect Cys in blood serum. In addition, due to its negligible cytotoxicity, the CDs-FITA can also be utilized for the real-time monitoring of endogenous cysteine (Cys) levels in living cells. Graphical abstract Illustration of the CD-based probe for Cys imaging in living cells.

Bisdemethoxycurcumin sensitizes cisplatin-resistant lung cancer cells to chemotherapy by inhibition of CA916798 and PI3K/AKT signaling.

Curcumin, a dietary supplement or herbal medicine from Curcuma longa, has shown antitumor activity in different cancer cell lines and clinical trials. CA916798, a novel protein, is overexpressed in multidrug-resistant tumor cells. This study aimed to assess the effects of curcumin on regulating chemosensitivity in cisplatin-resistant non-small cell lung cancer (NSCLC) cells in vitro and to explore the underlying molecular mechanisms. Human cisplatin-sensitive A549 and cisplatin-resistant A549/CDDP lung adenocarcinoma cells were treated with curcumin to assess cell viability and gene modulations using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blotting. CA916798 shRNA and point mutations were used to assess the CA916798 functions and phosphorylation sites. Bisdemethoxycurcumin sensitized cisplatin-resistant lung cancer cells to various chemotherapeutic agents, including cisplatin. Bisdemethoxycurcumin reduced the levels of CA916798 mRNA and protein in A549 and A549/CDDP cells, while it also suppressed phosphatidylinositol-3-kinase (PI3K)/AKT signaling. CA916798, as a downstream gene, interacted with AKT after bisdemethoxycurcumin treatment in A549 and A549/CDDP cells. Moreover, A549/CDDP cells expressing the point-mutated CA916798-S20D protein were more resistant to cisplatin and bisdemethoxycurcumin, whereas tumor cells expressing CA916798-S20A, CA916798-S31A, CA916798-S60A, CA916798-S93A, or CA916798-T97A (different sites of amino acid phosphorylation) showed similar sensitivity or resistance to cisplatin and bisdemethoxycurcumin, compared with the control cells. Bisdemethoxycurcumin is able to sensitize cisplatin-resistant NSCLC cells to chemotherapeutic agents by inhibition of CA916798 and PI3K/AKT activities. Moreover, phosphorylation of CA916798 at the S20 residue plays a critical role in mediating bisdemethoxycurcumin antitumor activity.

Deregulated methionine adenosyltransferase α1, c-Myc, and Maf proteins together promote cholangiocarcinoma growth in mice and humans(‡).

UNLABELLED: c-Myc induction drives cholestatic liver injury and cholangiocarcinoma (CCA) in mice, and induction of Maf proteins (MafG and c-Maf) contributes to cholestatic liver injury, whereas S-adenosylmethionine (SAMe) administration is protective. Here, we determined whether there is interplay between c-Myc, Maf proteins, and methionine adenosyltransferase α1 (MATα1), which is responsible for SAMe biosynthesis in the liver. We used bile duct ligation (BDL) and lithocholic acid (LCA) treatment in mice as chronic cholestasis models, a murine CCA model, human CCA cell lines KMCH and Huh-28, human liver cancer HepG2, and human CCA specimens to study gene and protein expression, protein-protein interactions, molecular mechanisms, and functional outcomes. We found that c-Myc, MATα1 (encoded by MAT1A), MafG, and c-Maf interact with one another directly. MAT1A expression fell in hepatocytes and bile duct epithelial cells during chronic cholestasis and in murine and human CCA. The opposite occurred with c-Myc, MafG, and c-Maf expression. MATα1 interacts mainly with Mnt in normal liver, but this switches to c-Maf, MafG, and c-Myc in cholestatic livers and CCA. Promoter regions of these genes have E-boxes that are bound by MATα1 and Mnt in normal liver and benign bile duct epithelial cells that switched to c-Myc, c-Maf, and MafG in cholestasis and CCA cells. E-box positively regulates c-Myc, MafG, and c-Maf, but it negatively regulates MAT1A. MATα1 represses, whereas c-Myc, MafG, and c-Maf enhance, E-box-driven promoter activity. Knocking down MAT1A or overexpressing MafG or c-Maf enhanced CCA growth and invasion in vivo. CONCLUSION: There is a novel interplay between MATα1, c-Myc, and Maf proteins, and their deregulation during chronic cholestasis may facilitate CCA oncogenesis. (Hepatology 2016;64:439-455).

Detection and comparison of microRNAs in the caprine mammary gland tissues of colostrum and common milk stages.

BACKGROUND: MicroRNAs (miRNAs) have a great influence on various physiological functions. A lot of high-throughput sequencing (HTS) research on miRNAs has been executed in the caprine mammary gland at different lactation periods (common milk lactation and dry period), but little is known about differentially expressed miRNAs in the caprine mammary gland of colostrum and peak lactation periods. RESULT: This study identified 131 differentially expressed miRNAs (P < 0.05 and log2 colostrum normalized expression (NE)/peak lactation NE > 1 or log2 colostrum NE/peak lactation NE < -1), including 57 known miRNAs and 74 potential novel miRNAs in the colostrum and peak lactation libraries. In addition, compared with differentially expressed miRNAs in the peak lactation period, 45 miRNAs in the colostrum lactation period were remarkably upregulated, whereas 86 miRNAs were markedly downregulated (P < 0.05 and log2 colostrum NE/peak lactation NE > 1 or log2 colostrum NE/peak lactation NE < -1). The expressions of 10 randomly selected miRNAs was analyzed through stem-loop real-time quantitative PCR (RT-qPCR). Their expression patterns were the same with Solexa sequencing results. Pathway analysis suggested that oestrogen, endocrine, adipocytokine, oxytocin and MAPK signalling pathways act on the development of mammary gland and milk secretion importantly. In addition, the miRNA-target-network showed that the bta-miR-574 could influence the development of mammary gland and lactation by leptin receptor (LEPR), which was in the adipocytokine signalling pathway. Chr5_3880_mature regulated mammary gland development and lactation through Serine/threonine-protein phosphatase (PPP1CA), which was in the oxytocin signalling pathway. CONCLUSIONS: Our finding suggested that the profiles of miRNAs were related to the physiological functions of mammary gland in the colostrum and peak lactation periods. The biological features of these miRNAs may help to clarify the molecular mechanisms of lactation and the development of caprine mammary gland.

An irradiation density dependent energy relaxation in plant photosystem II antenna assembly.

Plant photosystem II (PSII) is a multicomponent pigment-protein complex that harvests sunlight via pigments photoexcitation, and converts light energy into chemical energy. Against high light induced photodamage, excess light absorption of antenna pigments triggers the operation of photoprotection mechanism in plant PSII. Non-photochemical energy relaxation as a major photoprotection way is essentially correlated to the excess light absorption. Here we investigate the energy relaxation of plant PSII complexes with varying incident light density, by performing steady-state and transient chlorophyll fluorescence measurements of the grana membranes (called as BBY), functional moiety PSII reaction center and isolated light-harvesting complex LHCII under excess light irradiation. Based on the chlorophyll fluorescence decays of these samples, it is found that an irradiation density dependent energy relaxation occurs in the LHCII assemblies, especially in the antenna assembly of PSII supercomplexes in grana membrane, when irradiation increases to somewhat higher density levels. Correspondingly, the average chlorophyll fluorescence lifetime of the highly isolated BBY fragments gradually decreases from ~1680 to ~1360 ps with increasing the irradiation density from 6.1×10(9) to 5.5×10(10) photon cm(-2) pulse(-1). Analysis of the relation of fluorescence decay change to the aggregation extent of LHCIIs suggests that a dense arrangement of trimeric LHCIIs is likely the structural base for the occurrence of this irradiation density dependent energy relaxation. Once altering the irradiation density, this energy relaxation is quickly reversible, implying that it may play an important role in photoprotection of plant PSII.

Methionine adenosyltransferase 2B-GIT1 complex serves as a scaffold to regulate Ras/Raf/MEK1/2 activity in human liver and colon cancer cells.

Methionine adenosyltransferase 2B (MAT2B) encodes for variant proteins V1 and V2 that interact with GIT1 to increase ERK activity and growth in human liver and colon cancer cells. MAT2B or GIT1 overexpression activates MEK. This study explores the mechanism for MEK activation. We examined protein-protein interactions by co-immunoprecipitation and verified by confocal microscopy and pull-down assay using recombinant or in vitro translated proteins. Results were confirmed in an orthotopic liver cancer model. We found that MAT2B and GIT1-mediated MEK1/2 activation was not mediated by PAK1 or Src in HepG2 or RKO cells. Instead, MAT2B and GIT1 interact with B-Raf and c-Raf and enhance recruitment of Raf proteins to MEK1/2. MAT2B-GIT1 activates c-Raf, which is the key mediator for MEK/12 activation, because this still occurred in RKO cells that express constitutively active B-Raf mutant. The mechanism lies with the ability of MAT2B-GIT1 to activate Ras and promote B-Raf/c-Raf heterodimerization. Interestingly, MAT2B but not GIT1 can directly interact with Ras, which increases protein stability. Finally, increased Ras-Raf-MEK signaling occurred in phenotypically more aggressive liver cancers overexpressing MAT2B variants and GIT1. In conclusion, interaction between MAT2B and GIT1 serves as a scaffold and facilitates signaling in multiple steps of the Ras/Raf/MEK/ERK pathway, further emphasizing the importance of MAT2B/GIT1 interaction in cancer growth.

S-Adenosylmethionine and methylthioadenosine inhibit ß-catenin signaling by multiple mechanisms in liver and colon cancer.

S-Adenosylmethionine (SAMe), the principal methyl donor that is available as a nutritional supplement, and its metabolite methylthioadenosine (MTA) exert chemopreventive properties against liver and colon cancer in experimental models. Both agents reduced ß-catenin expression on immunohistochemistry in a murine colitis-associated colon cancer model. In this study, we examined the molecular mechanisms involved. SAMe or MTA treatment in the colitis-associated cancer model lowered total ß-catenin protein levels by 47 and 78%, respectively. In an orthotopic liver cancer model, increasing SAMe levels by overexpressing methionine adenosyltransferase 1A also reduced total ß-catenin levels by 68%. In both cases, lower cyclin D1 and c-Myc expression correlated with lower ß-catenin levels. In liver (HepG2) and colon (SW480, HCT116) cancer cells with constitutively active ß-catenin signaling, SAMe and MTA treatment inhibited ß-catenin activity by excluding it from the nuclear compartment. However, in liver (Huh-7) and colon (RKO) cancer cells expressing wild-type Wnt/ß-catenin, SAMe and MTA accelerated ß-catenin degradation by a glycogen synthase kinase 3-ß-dependent mechanism. Both agents lowered protein kinase B activity, but this was not mediated by inhibiting phosphoinositide 3-kinase. Instead, both agents increased the activity of protein phosphatase 2A, which inactivates protein kinase B. The effect of MTA on lowering ß-catenin is direct and not mediated by its conversion to SAMe, as blocking this conversion had no influence. In conclusion, SAMe and MTA inhibit Wnt/ß-catenin signaling in colon and liver cancer cells regardless of whether this pathway is aberrantly induced, making them ideal candidates for chemoprevention and/or chemotherapy in these cancers.