Odorants Identified in Chinese Dry-Cured Ham Contribute to Salty Taste Enhancement.

Jinhua dry-cured ham (JDH) is a traditional fermented Chinese meat product. We studied the dynamic sensory and emotional profiles of JDHs obtained by five preparation methods and the corresponding release of sodium ions (Na+), potassium ions (K+), and volatile organic compounds (VOCs) during oral processing. The VOCs with salty taste enhancement abilities were screened based on the correlations of VOCs with salty flavor and concentration of Na and K ions with salty flavor. A trained sensory panel evaluated the saltiness enhancements of selected VOCs by using static and dynamic sensory methods. The results revealed that Na+, K+, and selected VOCs were mainly released during 0-10 s of the chewing process. The release of Na+ and K+ in JDH residue samples exhibited consistently decreasing trends, while in saliva, their concentrations increased. The VOCs showing a high correlation with Na+ and K+ and salty flavor have saltiness enhancement abilities in both NaCl solutions and NaCl + MSG mixtures. Odor-induced saltiness was pronounced at low salt concentrations (0.2% NaCl). The investigation demonstrated 16 VOCs exhibiting saltiness enhancement abilities, including 4 pyrazines, 5 acids, 4 sulfur-containing compounds, and 3 other compounds. The sensory evaluation suggested pyrazines and sulfur-containing compounds as good saltiness enhancers. 2-Furfuryl mercaptan significantly enhanced the salty sensation in the NaCl + MSG solutions when compared with MSG alone (p < 0.05). This research provides evidence that certain odorants identified in JDHs exhibit salty-enhancing properties, indicating their potential for salt reduction at the industrial level.

Mechanism of Shenfu injection in suppressing inflammation and preventing sepsis-induced apoptosis in murine cardiomyocytes based on network pharmacology and experimental validation.

ETHNOPHARMACOLOGICAL RELEVANCE: Shenfu injection(SFI), as a famous classical Chinese patent medicine injection for the treatment of sepsis, has achieved good curative effects in clinical practice. However, its specific ingredients and molecular mechanisms is still unclear. AIM OF THE STUDY: To analyze the effective ingredients and molecular mechanisms of SFI in the treatment of sepsis via network pharmacology technology and experimental validation. MATERIALS AND METHODS: A total of 198 mice were used in this experiment. Septic mice model was performed by cecal ligation and puncture (CLP). First, Survival rates were calculted to screen the dosage and the treatment time window of SFI. Cardiac function was evaluated by echocardiography. The potential targets and pathways of SFI in the treatment of sepsis were predicted by network pharmacology. Myocardial tissue samples were harvest from different groups after CLP surgery. Hematoxylin-eosin (H&E) and TUNEL staining were used to examine the injury of heart. Western-blot analysis was performed to determine the protein expression of apoptosis. Meanwhile, the structural changes and mitochondrial membrane potential in the mitochondria of cardiomyocytes were also observed by transmission electron microscopy. RESULTS: The Kaplan-Meier survival analysis showed that SFI significantly improved the 7-day survival rate as compared with that of CLP mice (P < 0.05). Echocardiography analysis found that LVEF and FS were significantly reduced in CLP mice compared with Sham mice, while SFI significantly increased LVEF (P < 001). Network pharmacology analysis indicated that the potential targets with higher degrees include IL2, BCL2, BAX, CASP7, BID, CASP8. Pathways with higher degrees include apoptosis, TNF signaling pathway, mitochondrial pathway apoptosis, PI3K-AKT signaling pathway. SFI treatment markedly attenuated the quantity of apoptotic cells as compared with the CLP group (P < 0.01). Western blot analysis indicated that CLP surgery decreased the expression of Bcl-2 (anti-apoptotic) but improved the protein expression of Bid, t-Bid, Cyc (pro-apoptotic) as compared with the Sham group (P < 0.01). While, SFI treatment markedly prevent the expression of Bid, t-Bid, Cyc and Caspase-9. The myocardial mitochondrial membrane potential of CLP group decreased after CLP surgery, while the mitochondrial membrane potential of SFI group increased significantly. Compared with the CLP group, in SFI group, the Z-line of the sarcomere was clear and distinguishable, and swollen mitochondria were significantly improved. CONCLUSIONS: The present study demonstrated that SFI improved survival rate and cardiac function of septic mice mainly by suppressing inflammation and apoptosis.

Sepsis­induced cardiac dysfunction and pathogenetic mechanisms (Review).

Sepsis is a manifestation of the immune and inflammatory response to infection, which may lead to multi­organ failure. Health care advances have improved outcomes in critical illness, but it still remains the leading cause of death. Septic cardiomyopathy is heart dysfunction brought on by sepsis. Septic cardiomyopathy is a common consequence of sepsis and has a mortality rate of up to 70%. There is a lack of understanding of septic cardiomyopathy pathogenesis; knowledge of its pathogenesis and the identification of potential therapeutic targets may reduce the mortality rate of patients with sepsis and lead to clinical improvements. The present review aimed to summarize advances in the pathogenesis of cardiac dysfunction in sepsis, with a focus on mitochondrial dysfunction, metabolic changes and cell death modalities and pathways. The present review summarized diagnostic criteria and outlook for sepsis treatment, with the goal of identifying appropriate treatment methods for this disease.

A Meta-Analysis of the Effects of Levosimendan on Cardiac Function and Outcomes in Patients with Sepsis.

Objective: To systematically evaluate the effect of levosimendan on cardiac function and outcomes in patients with sepsis. Method: We searched multiple databases including CNKI, VIP, WanFang Data, WOS, PubMed, EMbase, and The Cochrane Library up to February 2023. We targeted RCTs comparing levosimendan with dobutamine as a control for treating sepsis. After a rigorous screening and quality evaluation, 18 studies were selected for meta-analysis using Review Manager 5.4. Results: Out of 18 studies involving 980 sepsis patients, the meta-analysis revealed the following for the levosimendan group compared to dobutamine: (1) A significant reduction in mortality rate (OR = 0.63, 95% CI (0.42,0.95), P = .03). (2) Shortened ICU stay (MD = -2.55, 95% CI (-3.12, -1.98), P < .00001). (3) Increased left ventricular ejection fraction (LVEF) (MD = 6.05, 95%CI (5.28, 6.81), P < .00001) and cardiac index (CI) (MD = 0.47, 95%CI (0.35, 0.59), P < .00001). (4) Decreased blood lactate (Lac) (MD = -1.31, 95%CI (-1.73, -0.90), P < .00001) and troponin I (TnI) levels (MD = -0.43, 95%CI (-0.66, -0.21), P = .0002). (5) Reduced incidence of adverse events (OR = 0.43, 95% CI (0.23,0.81), P = .008). Conclusions: Compared to dobutamine, levosimendan substantially enhances cardiac function in sepsis patients, leading to improved outcomes and fewer adverse events.

Application of GC-TOF/MS and GC×GC-TOF/MS to Discriminate Coffee Products in Three States (Bean, Powder, and Brew).

The volatiles in coffee play an important part in the overall flavor profile. In this study, GC-TOF/MS and GC×GC-TOF/MS were used to detect the volatile organic compounds (VOCs) in coffee samples of three different brands at three states (bean, powder, and brew). The differences between the two methods in characterizing VOCs were analyzed using the Venn diagram and PCA (principal component analysis). The important aroma-contributing compounds were further compared and analyzed. The results of the venn diagrams of different coffee samples showed that most VOCs existed in 2-3 kinds of coffee. The PCA of VOCs in different coffee samples showed that the VOCs detected by GC-TOF/MS could distinguish the coffee samples in the different states. GC×GC-TOF/MS was suitable for the further identification and differentiation of the different brands of coffee samples. In addition, pyridine, pyrrole, alcohols, and phenols greatly contributed to distinguishing coffee in three states, and alcohols greatly contributed to distinguishing the three brands of coffee.

Molecular Mechanism Pathways of Natural Compounds for the Treatment of Non-Alcoholic Fatty Liver Disease.

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world, and its incidence continues to increase each year. Yet, there is still no definitive drug that can stop its development. This review focuses mainly on lipotoxicity, oxidative stress, inflammation, and intestinal flora dysbiosis to understand NAFLD's pathogenesis. In this review, we used NCBI's PubMed database for retrieval, integrating in vivo and in vitro experiments to reveal the therapeutic effects of natural compounds on NAFLD. We also reviewed the mechanisms by which the results of these experiments suggest that these compounds can protect the liver from damage by modulating inflammation, reducing oxidative stress, decreasing insulin resistance and lipid accumulation in the liver, and interacting with the intestinal microflora. The natural compounds discussed in these papers target a variety of pathways, such as the AMPK pathway and the TGF-ß pathway, and have significant therapeutic effects. This review aims to provide new possible therapeutic lead compounds and references for the development of novel medications and the clinical treatment of NAFLD. It offers fresh perspectives on the development of natural compounds in preventing and treating NAFLD.

Fast and Non-Destructive Profiling of Commercial Coffee Aroma under Three Conditions (Beans, Powder, and Brews) Using GC-IMS.

The flavor of coffee can be affected by the preparation parameters. In this investigation, the flavor profiles of three coffee brands under three conditions (bean, powder, and brew) were analyzed by gas chromatography-ion mobility spectrometry (GC-IMS) and the electronic nose (E-nose). The flavor results were further studied using multiple factor analysis (MFA). A total of 117 peaks were identified in all coffee samples by GC-IMS, and the principal component analysis (PCA) showed these coffee samples could be grouped and separated. A total of 37 volatile organic compounds (VOCs) were selected as biomarkers to distinguish coffee samples, including 5 aldehydes, 10 ketones, 8 alcohols, 2 acids, 4 esters, 5 furans, and 3 other compounds. The comparison between E-nose and GC-IMS data using partial least squares regression (PLSR) and MFA showed GC-IMS could present very close sample spaces. Compared with E-nose, GC-IMS could not only be used to classify coffee samples in a very short time but also provide VOC bio-markers to discriminate coffee samples.

Dexmedetomidine Versus Propofol for Patients With Sepsis Requiring Mechanical Ventilation: A Systematic Review and Meta-Analysis.

Purpose: This meta-analysis was performed to access the influence of dexmedetomidine versus propofol for adult patients with sepsis undergoing mechanical ventilation. Materials and Methods: NCBI PUBMED, Cochrane Library, Embase, China National Knowledge Internet (CNKI), and China Biological Medicine (CBM) were searched. Revman 5.3 and Stata software (version 12.0, Stata Corp LP, College Station, TX, United States) were used for meta-analysis. Results: Fifteen studies were included, and the data from the included studies were incorporated into the meta-analysis. Also, the result shows that compared with propofol, dexmedetomidine does not reduce 28-day mortality [risk ratios (RR) =0.97, 95% confidence interval (CI) =0.83-1.13, p = 0.70]. However, our analysis found that dexmedetomidine could reduce intensive care unit (ICU) stays {standard mean difference (SMD): -0.15; 95% CI: [-0.30-(-0.01)], p = 0.03}, duration of mechanical ventilation {SMD: -0.22; 95% CI: [-0.44-(-0.01)], p = 0.043}, sequential organ failure assessment (SOFA) {SMD: -0.41; 95% CI: [-0.73-(-0.09)], p = 0.013}, levels of interleukin-6 (IL-6) at 24 h (SMD: -2.53; 95% CI: -5.30-0.24, p = 0.074), and levels of CK-MB at 72 h {SMD: -0.45; 95% CI: [-0.83-(-0.08)], p = 0.017}. Conclusions: This meta-analysis (MA) suggests that in terms of 28-day mortality, sepsis patients with the treatment of dexmedetomidine did not differ from those who received propofol. In addition, more high-quality trials are needed to confirm these findings. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/#recordDetails, identifier CRD42021249780.

The Efficacy and Safety of Esmolol for Septic Shock: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

Purpose: The meta-analysis aims to identify whether septic shock patients can benefit from esmolol. Materials and Methods: The relevant studies from MEDLINE, Cochrane Library, Embase were searched by two independent investigators using a variety of keywords. Stata software (version 12.0, Stata Corp LP, College Station, TX, United States)was used for statistical analysis. Results: A total of 14 studies were identified and incorporated into the meta-analysis. For overall analysis, the treatment of esmolol was associated with decreased 28-day mortality (RR = 0.66, 95% CI = 0.56-0.77, p < 0.001). Meanwhile, our analysis found that, esmolol could decrease HR (SMD: -1.70; 95% CI: [-2.24-(-1.17)], cTnI (SMD: -1.61; 95% CI: [-2.06-(-1.16)] compared with standard treatment. No significant differences between the two groups were found in MAP, Lac, CI, and SVI. Conclusion: The findings of this meta-analysis intend to demonstrate that septic shock patients with high heart beats rate might be benefit from esmolol treatment despite enough fluid resuscitation. While, dependent on the study published, with the further development of septic shock, the positive impact of esmolol varies. The appropriate heart rate change interval cannot be confirmed, further high-quality and large-scale RCTs should be performed to verify it and screening more suitable heart rate levels. Systematic Review Registration: CRD42021239513.

Punicalagin induces ROS-mediated apoptotic cell death through inhibiting STAT3 translocation in lung cancer A549 cells.

Lung cancer is a noxious disease with substandard overall survival. Despite this, there are several treatment strategies for lung cancer include chemotherapy, radiotherapy, surgery; however, the overall survival remains poor. Punicalagin has been documented as a potential phytomedicine to selectively inhibit the progression and expansion of numerous cancers. In the present study, we evaluated the antiproliferative ability of punicalagin against lung cancer A549 cells by inducing apoptosis by inhibiting STAT-3 activation. Punicalagin induces toxic effects of A549 cells in a dose-associated manner after 24 h treatment. And we also observed that punicalagin (10, 20, and 30 µM) induced reactive oxygen species generation, alters the mitochondrion membrane potential and apoptotic morphological changes in A549 cells. The STAT-3 overexpression regulates apoptosis, proliferation, and angiogenesis. Here, the punicalagin inhibited STAT-3 translocation and thereby induces apoptosis by inhibiting expression Bcl-2 and enhanced expression of Bax, cytochrome-c, caspase-9, and caspase-3 in A549 cells. Hence, we stated that the punicalagin is a possible therapy for non-small cell lung, malignancies. Altogether, the punicalagin is a promising phytomedicine in malignancy treatment and further endeavors are needed to unveil the complete potential.

Voltage-gated sodium channel 1.7 expression decreases in dorsal root ganglia in a spinal nerve ligation neuropathic pain model.

The role of the voltage-gated sodium channel 1.7 (Nav1.7) is unclear in models of neuropathic pain induced by nerve injury. In the present study, we measured expression levels of Nav1.7 in two distinct neuropathic pain models: spinal nerve ligation (SNL) and chronic constriction injury (CCI). In the SNL model, both mRNA and protein levels of Nav1.7 were markedly lower in the L5 dorsal root ganglia (DRG) but were significantly higher in the L4 DRG. Nav1.7 protein levels were notably higher in both L4 and L5 DRGs under CCI conditions. We found that excessive damage of L5 nerves such as SNL reduced expression levels of Nav1.7 in the injured L5 DRG and activated the adjacent uninjured DRG, resulting in Nav1.7 level increases in the adjacent L4 DRG. We confirmed again that Nav1.7 was closely related to neuropathic pain induced by nerve injury. More importantly, our results suggest that tracing the molecular changes exclusively in the L5 DRG in SNL model may not completely explain the pain mechanism; it is necessary to study the adjacent uninjured L4 DRG.

Effects of Kudiezi Injection on Serum Inflammatory Biomarkers in Patients with Acute Cerebral Infarction.

BACKGROUND: Kudiezi injection is a traditional Chinese medicine for acute cerebral infarction, but the exact mechanisms are poorly understood. OBJECTIVE: To investigate the mechanisms of Kudiezi injection on the inflammatory response in the treatment of acute cerebral infarction. METHODS: This was a prospective study of patients with acute cerebral infarction within 48 h of onset and treated between July 2012 and July 2016 at three hospitals in China. The patients were randomized to routine treatments (control group) versus routine treatments and Kudiezi injection (Kudiezi group). The National Institutes of Health Stroke Score was assessed on days 1, 3, 5, 7, and 14. The patients were tested for serum levels of pro- and anti-inflammatory cytokines (S100 calcium-binding protein B, neuron-specific enolase, interleukin-6, interleukin-10, interleukin-18, and matrix metaloproteinase-9; by enzyme-linked immunosorbent assay) immediately after admission and on days 3, 5, and 14. RESULTS: Stroke scores were improved in both groups from days 1 to 14. On days 5 and 7, stroke scores in the Kudiezi group were lower than in the control group (P < 0.05). Compared with controls, the Kudiezi group had lower serum S100 calcium-binding protein B on day 14; higher interleukin-6 and interleukin-10 on day 3; lower interleukin-6 and interleukin-18 on day 5; and lower interleukin-18 and matrix metaloproteinase-9 on day 14. CONCLUSION: Kudiezi injection could lead to early reduction of interleukin-6, interleukin-18, matrix metaloproteinase-9, neuron-specific enolase, and S100 calcium-binding protein B levels and increases of interleukin-10 levels in patients with acute ischemic stroke. This trial is registered with ClinicalTrials.gov NCT01636154.

Impact of O6-methylguanine-DNA methyltransferase expression on the drug resistance of clear cell renal cell carcinoma.

OBJECTIVE: The deoxyribonucleic acid-repair protein O(6)-methylguanine-deoxyribonucleic acid methyltransferase is a major determinant of resistance of cells to various alkylating drugs. Its expression profile is different in different cancer types. Here, we studied the expression and function of O(6)-methylguanine-deoxyribonucleic acid methyltransferase in clear cell renal cell carcinoma. METHODS: The expression of O(6)-methylguanine-deoxyribonucleic acid methyltransferase was evaluated in clear cell renal cell carcinoma tissues and cell lines by quantitative real-time polymerase chain reaction and immunohistochemistry. The relationship between O(6)-methylguanine-deoxyribonucleic acid methyltransferase expression and clinicopathological characteristics was analyzed. To further investigate the function of O(6)-methylguanine-deoxyribonucleic acid methyltransferase in clear cell renal cell carcinoma resistance to alkylating agents, siRNA targeting O(6)-methylguanine-deoxyribonucleic acid methyltransferase were used to silence the O(6)-methylguanine-deoxyribonucleic acid methyltransferase expression. RESULTS: We found that O(6)-methylguanine-deoxyribonucleic acid methyltransferase is over-expressed in clear cell renal cell carcinoma tissues and cell lines. O(6)-methylguanine-deoxyribonucleic acid methyltransferase expression is related with tumor progression in clear cell renal cell carcinoma patients. Up-regulation of O(6)-methylguanine-deoxyribonucleic acid methyltransferase plays a critical role in primary resistance to alkylating agents. CONCLUSIONS: The overexpression of O(6)-methylguanine-deoxyribonucleic acid methyltransferase contributes to resistance of clear cell renal cell carcinoma to standard chemotherapy. Our results have significance for understanding a new pathway of the development of drug resistance of clear cell renal cell carcinoma.

Characteristics and classification of hippocampal θ rhythm induced by passive translational displacement.

Theta rhythms in the hippocampus are believed to be the "metric" relating to various behavior patterns for free roaming rats. In this study, the theta rhythms were studied while rats either walked or were passively translated by a toy car on a linear track (referred to as WALK and TRANS respectively). For the similar running speeds in WALK and TRANS conditions, theta frequency and amplitude were both reduced during TRANS. Theta modulation of pyramidal cells during TRANS was reduced compared to that during WALK. Theta frequency was positively correlated with translation speed during TRANS. Theta rhythm remained apparent during TRANS and WALK after large dose of atropine sulfate (blocking the cholinergic pathway) was injected compared to still states. The present study demonstrated the patterns of theta rhythm induced by passive translation in rats and suggested that the Type I theta rhythm could occur during non-voluntary locomotion. We further argued that the perception of actual self-motion may be the underlying mechanism that initiates and modulates type I theta.

Sympathetic nervous system overactivity in the Wistar rat with proliferative lesions of ventral prostate induced by chronic stress.

OBJECTIVES: The sympathetic nervous system and hypothalamic-pituitary-adrenal axis have been known to be reactive to psychological factors such as stress in which several humoral factors are released. Growing data suggest that stress conditions could be associated with the development or aggravation of prostatic disease. The present study aims to investigate the influence of chronic stress and blockade of the sympathetic nerve on rat prostate. METHODS: We used 2 weeks of restraint water-immersion stress to induce a chronic psychological stress model of Wistar rats. Denervation of the peripheral sympathetic nerve was done by 6-hydroxydopamine (6-OHDA). Blood flow of ventral prostate, plasma catecholamine and cortisol were measured at the end of the experiment. The weight and secretions of dissected prostate lobes were measured and histology was performed by hematoxylin and eosin stain. RESULTS: After 14 days of stress, the blood flow of ventral prostate decreased and plasma cortisol increased. The apparent proliferation of epithelium of ventral lobes were observed and dorsolateral ones were almost unaffected. On the other hand, the hyperplasia changes were not seen after the chemical sympathectomy had been done during stress. CONCLUSIONS: Chronic stress may lead to hyperplasia of ventral prostate, the overactivity of sympathetic nervous system is involved in the pathogenesis of prostatic disease.

Expression of p53 isoforms in renal cell carcinoma.

BACKGROUND: Several isoforms of p53 have been reported, which may have varying functions and expressions. This study aimed to analyze the expression patterns of p53 isoforms in renal cell carcinoma (RCC) at the mRNA and protein levels and their associations with clinical and pathologic factors to explore the mechanism of p53 isoforms' activity in RCC. METHODS: The specimens of tumours (T) and clinically normal tissues (N) adjacent to them were collected from 41 patients with RCC. mRNA expression levels of p53 isoforms were detected using RT-PCR followed by nested PCR. Protein expression levels were detected using immunohistochemisty and Western blotting with the anti-p53 antibodies DO-1 and DO-12. The data were analyzed with clinicopathological features by chi(2) test or Fisher's exact test. RESULTS: p53 mRNA was expressed in all tumours and matched clinically normal tissue adjacent to the tumour. All six isoforms could be detected in tumour and normal tissues, with the exception of the Delta133p53beta isoform, which was not detected in the normal tissue. Of the six isoforms, p53beta mRNA was significantly overexpressed in tumour samples (P < 0.001), and correlated with tumour stage. Nested PCR results consistently indicated the presence of p53gamma (19T/22N), Delta133p53 (33T/26N), Delta133p53beta (2T/0N), and Delta133p53gamma (13T/9N). Immunohistochemical analysis showed that p53 was expressed only in tumour tissues and correlated with tumour stage and grade. The results of Western blotting analysis were consistent with these findings. CONCLUSIONS: Although all six isoforms are present in RCC, their function in tumour development or progression might be different. Our findings suggest that p53beta might play an important role in the formation of RCC and it might be used as a new predictor and therapeutic target for RCC.

Lysine-specific demethylase 1 (LSD1) Is required for the transcriptional repression of the telomerase reverse transcriptase (hTERT) gene.

BACKGROUND: Lysine-specific demethylase 1 (LSD1), catalysing demethylation of mono- and di-methylated histone H3-K4 or K9, exhibits diverse transcriptional activities by mediating chromatin reconfiguration. The telomerase reverse transcriptase (hTERT) gene, encoding an essential component for telomerase activity that is involved in cellular immortalization and transformation, is silent in most normal human cells while activated in up to 90% of human cancers. It remains to be defined how exactly the transcriptional activation of the hTERT gene occurs during the oncogenic process. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we determined the effect of LSD1 on hTERT transcription. In normal human fibroblasts with a tight hTERT repression, a pharmacological inhibition of LSD1 led to a weak hTERT expression, and a robust induction of hTERT mRNA was observed when LSD1 and histone deacetylases (HDACs) were both inhibited. Small interference RNA-mediated depletion of both LSD1 and CoREST, a co-repressor in HDAC-containing complexes, synergistically activated hTERT transcription. In cancer cells, inhibition of LSD1 activity or knocking-down of its expression led to significant increases in levels of hTERT mRNA and telomerase activity. Chromatin immunoprecipitation assay showed that LSD1 occupied the hTERT proximal promoter, and its depletion resulted in elevated di-methylation of histone H3-K4 accompanied by increased H3 acetylation locally in cancer cells. Moreover, during the differentiation of leukemic HL60 cells, the decreased hTERT expression was accompanied by the LSD1 recruitment to the hTERT promoter. CONCLUSIONS/SIGNIFICANCE: LSD1 represses hTERT transcription via demethylating H3-K4 in normal and cancerous cells, and together with HDACs, participates in the establishment of a stable repression state of the hTERT gene in normal or differentiated malignant cells. The findings contribute to better understandings of hTERT/telomerase regulation, which may be implicated in the development of therapeutic strategies for telomerase dysregulation-associated human diseases including cancers.

The opposing effect of hypoxia-inducible factor-2alpha on expression of telomerase reverse transcriptase.

Hypoxia-inducible factor-1alpha (HIF-1alpha) has been implicated in the transcriptional regulation of the telomerase reverse transcriptase (hTERT) gene expression and telomerase activity, essential elements for cellular immortalization and transformation. However, controversial results were obtained in different studies. Moreover, it is totally unclear whether HIF-2alpha, the paralog of HIF-1alpha, plays a role in regulating hTERT expression. In the present study, we found that hypoxic treatment enhanced hTERT mRNA expression and telomerase activity in three renal cell carcinoma (RCC) cell lines with different genetic backgrounds. Both HIF-1alpha and HIF-2alpha were capable of significantly increasing the hTERT promoter activity in these cells. Moreover, depleting HIF-2alpha led to a down-regulation of hTERT mRNA level in RCC A498 cells expressing constitutive HIF-2alpha. It was found that HIF-2alpha bound to the hTERT proximal promoter and enhanced the recruitment of the histone acetyltransferase p300 and histone H3 acetylation locally in A498 cells treated with hypoxia. Increased levels of hTERT mRNA were observed in two of three hypoxia-treated malignant glioma cell lines. However, HIF-1alpha stimulated whereas HIF-2alpha inhibited the hTERT promoter activity in these glioma cell lines. Ectopic expression of HIF-2alpha resulted in diminished hTERT expression in glioma cells. Collectively, HIF-1alpha activates hTERT and telomerase expression in both RCC and glioma cells, and HIF-2alpha enhances hTERT expression in RCC cells, whereas it represses the hTERT transcription in glioma cells. These findings reveal a complex relationship between HIF-1alpha/2alpha and hTERT/telomerase expression in malignant cells, which may have both biological and clinical implications.

The telomerase reverse transcriptase (hTERT) gene is a direct target of the histone methyltransferase SMYD3.

Recent evidence has accumulated that the dynamic histone methylation mediated by histone methyltransferases and demethylases plays key roles in regulation of chromatin structure and transcription. In the present study, we show that SET and MYND domain-containing protein 3 (SMYD3), a histone methyltransferase implicated in oncogenesis, directly trans-activates the telomerase reverse transcriptase (hTERT) gene that is essential for cellular immortalization and transformation. SMYD3 occupies its binding motifs on the hTERT promoter and is required for maintenance of histone H3-K4 trimethylation, thereby contributing to inducible and constitutive hTERT expression in normal and malignant human cells. Knocking down SMYD3 in tumor cells abolished trimethylation of H3-K4, attenuated the occupancy by the trans-activators c-MYC and Sp1, and led to diminished histone H3 acetylation in the hTERT promoter region, which was coupled with down-regulation of hTERT mRNA and telomerase activity. These results suggest that SMYD3-mediated trimethylation of H3-K4 functions as a licensing element for subsequent transcription factor binding to the hTERT promoter. The present findings provide significant insights into regulatory mechanisms of hTERT/telomerase expression; moreover, identification of the hTERT gene as a direct target of SMYD3 contributes to a better understanding of SMYD3-mediated cellular transformation.

Switch to full-length of XAF1 mRNA expression in prostate cancer cells by the DNA methylation inhibitor.

X-linked inhibitor of apoptosis protein (XIAP) suppresses apoptotic cell death by binding to caspases and inhibiting their functions, while the XIAP-associated factor1 (XAF1), a zinc finger protein, antagonizes XIAP activities, thereby promoting apoptosis. The aberrant silence of the XAF1 gene has recently been found in various types of cancer cells, which is suggested to be one of the potential mechanisms underlying survival advantages of malignant cells. In the present study, we investigated the XAF1 expression in prostate cancer cells. Compared with normal tissues where a full-length of XAF1 mRNA is predominant, LNCaP and DU145 prostate cancer cell lines only expressed a short form of XAF1 transcripts, whereas PC3 cells exhibited a complete silence of the XAF1 gene. Inhibition of DNA methylation led to a switch to the full length of XAF1 mRNA expression in LNCaP and DU145 cells. The down-regulation of XAF1 expression was also observed in 6/8 tumor samples derived from patients with prostate cancer. Our findings suggest that splicing alterations or downregulation of the XAF1 transcript may occur during the development of prostate cancers due to the aberrant DNA methylation. The alternative splicing of XAF1 mRNA leads to formation of a truncated XAF1 protein with 19 amino acid deletion in its zinc finger domain, which likely affects its functional interaction with XIAP, and consequently, contributes to the pathogenesis of prostate cancers by disrupting balance of the apoptosis machinery.