Sphingosine-1-phosphate Attenuates Endoplasmic Reticulum Stress-induced Cardiomyocyte Apoptosis Through Sphingosine-1-phosphate Receptor 1.

BACKGROUND: Endoplasmic reticulum stress (ER stress) is involved in the development and progression of various forms of heart disease and may lead to myocardial apoptosis. Sphingosine-1-phosphate (S1P) possesses cardioprotective properties, including anti-apoptosis. However, little is known about the link between S1P and ER stress-induced myocardial apoptosis. This study investigated the regulatory role of S1P in ER stress-induced apoptosis in cardiomyocytes. METHODS: ER stress and myocardial apoptosis were induced by transverse aortic constriction (TAC) or tunicamycin in mice, which were then treated with 2-acetyl-5-tetrahydroxybutyl imidazole (THI) or S1P. AC16 cells were treated with tunicamycin or thapsigargin, or pretreated with S1P, sphingosine-1-phosphate receptor (S1PR) subtype antagonists, S1PR1 agonist, and PI3K and MEK inhibitors. Cardiac function, the level of S1P in plasma and heart, ER stress markers, cell viability, and apoptosis were detected. RESULTS: S1P reduced the expression of ER stress-related molecules and ER stress-induced myocardial apoptosis in mice subjected to TAC or an injection of tunicamycin. Furthermore, in AC16 cells exposed to thapsigargin or tunicamycin, S1P decreased the expression of ER stress-related molecules, promoting cell viability and survival. Nevertheless, the S1PR1 antagonist abrogated the protection of S1P. Subsequently, in TAC S1PR1 heterozygous (S1PR1+/-) mice, S1P had no effect on ER stress and apoptosis in cardiomyocytes. Notably, in vitro, the impact of anti-ER stress-induced myocardial apoptosis by the S1PR1 agonist was reversed by PI3K and MEK inhibitors. CONCLUSION: This study is the first to demonstrate that S1P relieves ER stress-induced myocardial apoptosis via S1PR1/AKT and S1PR1/ERK1/2, which are potential therapeutic targets for heart disease.

Chlorpromazine Efficiently Treats the Crisis of Pheochromocytoma: Four Case Reports and Literature Review.

Pheochromocytoma multisystem crisis (PMC) is a potentially lethal emergency due to catecholamine secretion. The condition manifests as severe hypertension to intractable cardiogenic shock and has a high mortality rate. This study explored the efficacy and safety of applying chlorpromazine on PMC patients. The study included seven patients (median age, 42 years; range, 14-57 years) diagnosed with pheochromocytoma. Four consecutive PMC patients were admitted to our critical care unit between 2016 and 2020 due to abdominal or waist pain, nausea, and vomiting. Their blood pressure (BP) fluctuated between 200-330/120-200 and 40-70/30-50 mmHg. Chlorpromazine (25 or 50 mg) was injected intramuscularly, followed by continuous intravenous infusion (2-8 mg/h). The patients' BP decreased to 100-150/60-100 mmHg within 1-3 h and stabilized within 3-5 days. Two weeks later, surgical tumor resection was successfully performed in all four patients. Similar clinical outcomes were also obtained in three patients with sporadic PMC reported in the literature who received chlorpromazine treatment, which reduced their BP readings from >200/100 mmHg to 120/70 mmHg. Our observations, combined with sporadic reports, showed that chlorpromazine efficiently controlled PMC. Thus, future studies on the use of chlorpromazine are warranted.

Machine learning-aided risk stratification system for the prediction of coronary artery disease.

BACKGROUND: Machine learning (ML) may be helpful to simplify the risk stratification of coronary artery disease (CAD). The current study aims to establish a ML-aided risk stratification system to simplify the procedure of the diagnosis of CAD. METHODS AND RESULTS: 5819 patients with coronary artery angiography (CAG) from July 2015 and December 2018 in our hospital, 2583 patients (aged 56 ± 11, <50% stenosis) and 3236 patients (aged 60 ± 10, ≥50% stenosis), available on age, sex, history of smoking, systolic and diastolic blood pressure, total cholesterol level, low- and high-density lipoprotein, triglyceride level, glycosylated hemoglobin A1c and uric acid were included in the ensemble model of ML. Receiver-operating characteristic curves showed that area-under-the-curve of the training data (90%) and the testing data (10%) were 0.81 and 0.75 (P = 0.006483). The validation data of 582 patients with CAG from July 2019 to September 2019 in our hospital showed the same predictive rate of the testing data. The low-risk group (risk probability<0.2) without the treatment of hypertension, diabetes and CAD could be probably excluded the diagnosis of CAD, the moderate-risk group (risk probability 0.2-0.8) would need further examination, and high-risk group (risk probability>0.8) would suggested to perform CAG directly. CONCLUSION: Machine learning-aided detection system with the clinical data of age, sex, history of smoking, systolic and diastolic blood pressure, total cholesterol level, low- and high-density lipoprotein, triglyceride level, glycosylated hemoglobin A1c and uric acid could be helpful for the risk stratification of prediction for the coronary artery disease.

Management perspectives from the 2019 Wuhan international workshop on fulminant myocarditis.

Fulminant myocarditis (FM) is a form of acute myocardial inflammation leading to rapid-onset hemodynamic instability due to cardiogenic shock or life-threatening arrhythmias. As highlighted by recent registries, FM is associated with high rates of death and heart transplantation, regardless of the underlying histology. Because of a paucity of evidence-based management strategies exists for this disease, an International workshop on FM was held in Wuhan, China, in October 2019, in order to share knowledge on the disease and identify areas of consensus. The present report highlights both agreements and controversies in FM management across the world, focusing the attention on areas of opportunity, FM definition, the use of endomyocardial biopsy and viral identification on heart specimens, treatment algorithms including immunosuppression and the timing of circulatory support escalation. This report incorporates the most recent recommendations from national and international professional societies. Main areas of interest and aims of future prospective observational registries and randomized controlled trials were finally identified and suggested.

Longitudinal correlation of biomarkers of cardiac injury, inflammation, and coagulation to outcome in hospitalized COVID-19 patients.

BACKGROUND: Cardiac injury, as measured by troponin elevation, has been reported among hospitalized coronavirus disease 2019 (COVID-19) patients and portends a poor prognosis. However, how the dynamics of troponin elevation interplay with inflammation and coagulation biomarkers over time is unknown. We assessed longitudinal follow-up of cardiac injury, inflammation and coagulation markers in relation to disease severity and outcome. METHODS: We retrospectively assessed 2068 patients with laboratory-confirmed COVID-19 between January 29 and April 1, 2020 at Tongji Hospital in Wuhan, China. We defined cardiac injury as an increase in high sensitivity cardiac troponin-I (hs-cTnI) above the 99th of the upper reference limit. We explored the dynamics of elevation in hs-cTnI and the relationship with inflammation (interleukin [IL]-6, IL-8, IL-10, IL-2 receptor, tumor necrosis factor-α, C-reactive protein) and coagulation (d-dimer, fibrinogen, international normalized ratio) markers in non-critically ill versus critically ill patients longitudinally and further correlated these markers to survivors and non-survivors. RESULTS: Median age was 63 years (first to third quartile 51-70 years), 51.4% of whom were women. When compared to non-critically ill patients (N = 1592, 77.0%), critically ill (defined as requiring mechanical ventilation, in shock or multiorgan failure) patients (N = 476, 23.0%), had more frequent cardiac injury on admission (30.3% vs. 2.3%, p < 0.001), with increased mortality during hospitalization (38.4% vs. 0%, p < 0.001). Among critically ill patients, non-survivors (N = 183) had a continuous increase in hs-cTnI levels during hospitalization, while survivors (N = 293) showed a decrease in hs-cTnI level between day 4 and 7 after admission. Specifically, cardiac injury is an independent marker of mortality among critically ill patients at admission, day 4-7 and 8-14. Consistent positive correlations between hs-cTnI and interleukin (IL)-6 on admission (r = 0.59), day 4-7 (r = 0.66) and day 8-14 (r = 0.61; all p < 0.001) and d-dimer (at the same timepoints r = 0.54; 0.65; 0.61, all p < 0.001) were observed. A similar behavior was observed between hs-cTnI and most of other biomarkers of inflammation and coagulation. CONCLUSIONS: Cardiac injury commonly occurs in critically ill COVID-19 patients, with increased levels of hs-cTnI beyond day 3 since admission portending a poor prognosis. A consistent positive correlation of hs-cTnI with IL-6 and d-dimer at several timepoints along hospitalization could suggest nonspecific cytokine-mediated cardiotoxicity.

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.

Pretreatment of rAAV-Mediated Expression of Myostatin Propeptide Lowers Type 2 Diabetes Incidence in C57BL/6 Mice on a High-Fat Diet.

Myostatin, a negative modulator of muscle growth, has been considered as a potential target for the treatment of type 2 diabetes (T2D). In previous work, it was found that myostatin inhibition by adeno-associated virus (AAV)-mediated gene delivery of myostatin propeptide (MPRO) could improve muscle mass and achieve therapeutic effects on glucose regulation and lipid metabolism in db/db mice. This study investigated whether pre-intervention of rAAV-mediated expression of MPRO could lower the incidence of T2D. Three-week-old male C57BL/6 mice were randomly divided into saline control, rAAV-GFP, and rAAV-MPRO groups, all of which were fed on a high-fat diet. It was observed that pre-intervention of rAAV-MPRO prevented high-fat diet-induced hyperglycemia and hyperlipidemia. It also improved glucose tolerance, downregulated serum insulin levels, and facilitated the growth of skeletal muscle and fat redistribution, with no significant difference in serum free fatty acid levels and body weight, which ultimately reduced the incidence of T2D. In addition, pretreatment of rAAV-MPRO in C2C12 cells increased insulin-stimulated glucose uptake, as well as glycogen synthesis under insulin resistance conditions induced by free fatty acids, with no significant difference in insulin-stimulated glucose oxidation. Finally, the study demonstrated that improved glucose metabolism by rAAV-MPRO pretreatment might be due to the activation of the PI3K/Akt/GSK3ß pathway and spurring Glut4 transposition from the cytoplasm to the cytomembrane in C2C12 cells. Based on these findings, MPRO is most likely to be a new method for the prevention of T2D.

miR-1322 regulates ChREBP expression via binding a 3'-UTR variant (rs1051943).

The carbohydrate response element-binding protein (ChREBP), also referred to as MLXIPL, plays a crucial role in the regulation of glucose and lipid metabolism. Existing studies have shown an association between genetic variations of the ChREBP gene and lipid levels, such as triglycerides and high-density lipoprotein cholesterol. However, mechanistic studies of this association are limited. In this study, bioinformatic analysis revealed that the polymorphism rs1051943A occurs in the complementary binding sequence of miR-1322 in the ChREBP 3'-untranslated region (UTR). Studies of potential mechanisms showed that the A allele could facilitate miR-1322 binding, and luciferase activity significantly decreased when co-transfected with a ChREBP 3'-UTR luciferase reporter vector and miR-1322 mimics in HepG2 cells. Furthermore, miR-1322 significantly regulated the expression of ChREBP downstream genes and reduced the synthesis of lipids. The expression of miR-1322 was up-regulated by glucose and palmitic acid stimulation. Population studies showed that rs1051943-A allele was only found in the Han Chinese and Uighur ethnic groups, different from European populations (G allele frequency = 0.07). In summary, we provide evidence that the rs1051943 A allele creates a functional miR-1322 binding site in ChREBP 3'-UTR and post-transcriptionally down-regulates its expression, possibly associated with levels of plasma lipids and glucose.

An APOC3 3'UTR variant associated with plasma triglycerides levels and coronary heart disease by creating a functional miR-4271 binding site.

Apolipoprotein C-III (APOC3) is a key regulator of plasma triglycerides levels. Increasing evidence has shown that loss-of-function mutations in APOC3 is associated with reduction in plasma triglycerides levels and will confer a benefit in patients at high risk for cardiovascular disease. However, these favorable mutations were extremely distribution discrepant among different ethnics. In this study, the APOC3 gene was resequenced and we identified a common variant which located in the microRNA-binding site in APOC3 and would affect its expression and the risk of coronary heart disease (CHD). The molecular mechanism was explored. We found that the T allele of rs4225 suppressed APOC3 translation by facilitating miR-4271 binding, but not the G allele. Subjects carrying the GG genotype had higher plasma APOC3 levels (p for trend = 0.03) than those with the TT genotype. Furthermore, the T allele was significantly associated with decreased triglyceride levels [Beta (SE): -0.024 (0.020), P = 0.03]. Finally, the case-control study suggested that the TT genotype resulted in a significant reduction in overall CHD risk [OR, 0.89 (95% confidence interval, 0.77-0.98), P = 0.009]. In conclusion, our results provide evidence that the rs4225 in the 3'-UTR of APOC3 might contribute to the risk of CHD by interfering with miR-4271 binding.

Overcoming Insulin Insufficiency by Forced Follistatin Expression in ß-cells of db/db Mice.

Diabetes poses a substantial burden to society as it can lead to serious complications and premature death. The number of cases continues to increase worldwide. Two major causes of diabetes are insulin resistance and insulin insufficiency. Currently, there are few antidiabetic drugs available that can preserve or protect ß-cell function to overcome insulin insufficiency in diabetes. We describe a therapeutic strategy to preserve ß-cell function by overexpression of follistatin (FST) using an AAV vector (AAV8-Ins-FST) in diabetic mouse model. Overexpression of FST in the pancreas of db/db mouse increased ß-cell islet mass, decreased fasting glucose level, alleviated diabetic symptoms, and essentially doubled lifespan of the treated mice. The observed islet enlargement was attributed to ß-cell proliferation as a result of bioneutralization of myostatin and activin by FST. Overall, our study indicates overexpression of FST in the diabetic pancreas preserves ß-cell function by promoting ß-cell proliferation, opening up a new therapeutic avenue for the treatment of diabetes.

P-450-dependent epoxygenase pathway of arachidonic acid is involved in myeloma-induced angiogenesis of endothelial cells.

P-450-dependent epoxygenase pathway of arachidonic acid and the products of epoxyeicosatrienoic acids (EETs) have been demonstrated to be involved in angiogenesis and tumor progression. This study examined the expression of EETs and the role of the pathway in the angiogenesis of multiple myeloma (MM). MM cell lines of U266 and RPMI8226 were cultured, and the EETs levels (11, 12-EET and 14, 15-EET) in the supernatant were determined by ELISA. Human umbilical vein endothelial cells (HUVECs) were cultured and used for analysis of the angiogenesis activity of the two MM cell lines, which was examined both in vitro and in vivo by employing MTT, chemotaxis, tube formation and matrigel plug assays. 11, 12-EET and 14, 15-EET were found in the supernatant of the cultured MM cells. The levels of the two EETs in the supernatant of U266 cells were significantly higher than those in the RPMI8226 cell supernatant (P<0.05), and the levels paralleled the respective angiogenesis activity of the two different MM cell lines. 17-octadecynoic acid (17-ODYA), as a specific inhibitor of P450 enzyme, suppressed HUVECs proliferation and tube formation induced by MM cells. Furthermore, 17-ODYA decreased the EET levels in the supernatant of MM cells. These results suggest that EETs may play an important role in the angiogenesis of MM, and the inhibitor 17-ODYA suppresses this effect.

Post-Natal knockdown of fukutin-related protein expression in muscle by long-termRNA interference induces dystrophic pathology [corrected].

Limb-girdle muscular dystrophy 2I (LGMD2I) is caused by mutations in the fukutin-related protein (FKRP) gene. Unlike its severe allelic forms, LGMD2I usually involves slower onset and milder course without defects in the central nervous system. The lack of viable animal models that closely recapitulate LGMD2I clinical phenotypes led us to use RNA interference technology to knock down FKRP expression via postnatal gene delivery so as to circumvent embryonic lethality. Specifically, an adeno-associated viral vector was used to deliver short hairpin (shRNA) genes to healthy ICR mice. Adeno-associated viral vectors expressing a single shRNA or two different shRNAs were injected one time into the hind limb muscles. We showed that FKRP expression at 10 months postinjection was reduced by about 50% with a single shRNA and by 75% with the dual shRNA cassette. Dual-cassette injection also reduced a-dystroglycan glycosylation and its affinity to laminin by up to 70% and induced α-dystrophic pathology, including fibrosis and central nucleation, in more than 50% of the myofibers at 10 months after injection. These results suggest that the reduction of approximately or more than 75% of the normal level of FKRP expression induces chronic dystrophic phenotypes in skeletal muscles. Furthermore, the restoration of about 25% of the normal FKRP level could be sufficient for LGMD2I therapy to correct the genetic deficiency effectively and prevent dystrophic pathology.

The epoxyeicosatrienoic acid-stimulated phosphorylation of EGF-R involves the activation of metalloproteinases and the release of HB-EGF in cancer cells.

AIM: To test the hypothesis that the epoxyeicosatrienoic acid (EET)-induced transactivation of EGF-R depends on the activation of metalloproteinases and the subsequent release of HB-EGF in cancer cells. METHODS: Exogenous 14,15-EET were added to four human-derived cancer cell lines Tca-8113, A549, HepG2, and MDA-MB-231, or these same cell lines were transfected with a mutant CYP epoxygenase (CYP102 F87V, an active 14,15-epoxygenase). The effects of elevated EET levels on the phosphorylation of tyrosine residues in the EGF receptor and on ERK1/2 activation were then assessed. RESULTS: Both the addition of 14,15-EET and the transfection of cells with CYP102 F87V markedly increased the phosphorylation of the tyrosine residues of EGF-R and ERK1/2, an effect that was blocked by a selective EGF-R tyrosine kinase inhibitor (tyrphostin AG1478), a broad-spectrum metalloproteinase inhibitor (1,10-phenanthroline), and an inhibitor of HB-EGF release (CRM197) in Tca-8113 cells. In addition, AG1478, 1,10-phenanthroline, and CRM197 also inhibited the tyrosine phosphorylation of EGF-R and ERK1/2 that was induced by 14,15-EET in the A549, HepG2, and MDA-MB-231 cell lines. CONCLUSION: These results suggest that the EET-induced transactivation of EGF-R depends on activation of metalloproteinases and the subsequent release of HB-EGF in cancer cell lines.

Expression of cytochrome P450 arachidonic acid epoxygenase 2J2 in human tumor tissues and cell lines.

BACKGROUND AND OBJECTIVE: Cytochrome P450 arachidonic acid epoxygenase 2J2 (CYP2J2) is a new metabolic pathway of arachidonic acid. However, its biological effects, especially pathophysiologic significance in human beings, remain to be further recognized. This study was to determine the expression of CYP2J2 in human tumor tissues and cell lines. METHODS: The expression of CYP2J2 mRNA and protein in 130 specimens of human carcinoma and related adjacent normal tissues, four specimens of inflammatory pseudotumor tissues, eight human tumor cell lines and two normal cell lines (as control) was detected by reverse transcription-polymerase chain reaction (RT-PCR), western blot and immunohistochemistry. RESULTS: CYP2J2 was highly expressed in 101 (78%) carcinoma tissues, but was not detected in adjacent normal tissues and inflammatory pseudo-tumor tissues. Its mRNA level was obviously correlated to its protein level (r = 0.613, p < 0.01). Immunohistochemistry analysis showed the same results as RT-PCR and western blot. Furthermore, CYP2J2 was only expressed in cancer cells but not in interstitial and inflammatory cells. CYP2J2 was highly expressed in all carcinoma cell lines, but not in two normal cell lines. CONCLUSION: CYP2J2 is highly and selectively expressed in human tumor tissues and cell lines and may be a novel biomarker of human tumors.

Effects of cytochrome P450 arachidonic acid epoxygenases on the proliferation of tumor cells.

BACKGROUND AND OBJECTIVE: Cytochrome P450 (CYP) arachidonic acid epoxygenases promote cell proliferation and inhibit apoptosis in endothelial cells. This study was to investigate the effects of CYP epoxygenases on the proliferation of tumor cells and possible signaling pathways. METHODS: The effects of recombinant adeno-associated virus (rAAV) mediated cytochrome P450 2J2 (CYP2J2), cytochrome P450 F87V (CYPF87V) and anti-CYP2J2 on proliferation of Tca-8113, A549, Ncl-H446 and HepG2 cells were measured using MTT and flow cytometry. Expressions of phosphorylated epidermal growth factor receptor (EGFR), extracellular signal-regulated kinase (ERK)1/2 and Akt before and after transfection were detected by western blot. Tca-8113 cells infected with rAAV-CYP2J2, rAAV-CYPF87V, rAAV-antiCYP2J2 and rAAV-GFP were inoculated into nude mice, to observe the effect of CYP epoxygenases on the growth of xenografts. RESULTS: Infection of Tca-8113, A549, Ncl-H446 and HepG2 cells with rAAV-CYP2J2 and rAAVCYPF87V significantly increased the proliferation of tumor cells by 1.7-, 1.4-, 1.6- and 2.2-fold, and 2.0-, 1.5-, 1.8- and 2.0-fold respectively, as compared with control cells. On the contrary, infection with rAAV-antiCYP2J2 inhibited the proliferation of the four tumor cell lines. Moreover, CYP epoxgenases remarkably enhanced phosphorylation of EGFR, ERK1/2 and Akt, and upregulated total PI3K by 2-, 2.3-, 2.4- and 1.9-fold in the four cell lines, while rAAV-antiCYP2J2 exerted an inhibition effect. Infection of CYP450 epoxygenase genes markedly increased the cell percentage in S/G(2)/M phases by 210% as compared to control Tca-8113 cells. rAAV-CYP2J2 and rAAV-CYPF87V promoted tumor growth of Tca-8113 cell xenografts in nude mice in comparison to the control and rAAV-antiCYP2J2 groups. CONCLUSION: CYP epoxygenases efficiently promote the proliferation of tumor cells, which may be related with the activation of EGFR, ERK1/2 and PI3K/Akt signaling pathways.

A myocardium tropic adeno-associated virus (AAV) evolved by DNA shuffling and in vivo selection.

To engineer gene vectors that target striated muscles after systemic delivery, we constructed a random library of adeno-associated virus (AAV) by shuffling the capsid genes of AAV serotypes 1 to 9, and screened for muscle-targeting capsids by direct in vivo panning after tail vein injection in mice. After 2 rounds of in vivo selection, a capsid gene named M41 was retrieved mainly based on its high frequency in the muscle and low frequency in the liver. Structural analyses revealed that the AAVM41 capsid is a recombinant of AAV1, 6, 7, and 8 with a mosaic capsid surface and a conserved capsid interior. AAVM41 was then subjected to a side-by-side comparison to AAV9, the most robust AAV for systemic heart and muscle gene delivery; to AAV6, a parental AAV with strong muscle tropism. After i.v. delivery of reporter genes, AAVM41 was found more efficient than AAV6 in the heart and muscle, and was similar to AAV9 in the heart but weaker in the muscle. In fact, the myocardium showed the highest gene expression among all tissues tested in mice and hamsters after systemic AAVM41 delivery. However, gene transfer in non-muscle tissues, mainly the liver, was dramatically reduced. AAVM41 was further tested in a genetic cardiomyopathy hamster model and achieved efficient long-term delta-sarcoglycan gene expression and rescue of cardiac functions. Thus, direct in vivo panning of capsid libraries is a simple tool for the de-targeting and retargeting of viral vector tissue tropisms facilitated by acquisition of desirable sequences and properties.

[Promotive effects of epoxyeicosatrienoic acids (EETs) on proliferation of tumor cells].

BACKGROUND & OBJECTIVE: Epoxyeicosatrienoic acids (EETs) are generated from arachidomic acid by cytochrome P450(CYP). Previous studies revealed very strong and selective expression of CYP expoxygenase in human cancer tissues, but almost none in adjacent normal tissues. This study was to investigate the promotive effect of EETs on proliferation of tumor cells and the possible mechanisms. METHODS: Four tumor cell lines, Tca-8113, A549, Ncl-H446 and HepG2, were treated with different concentrations of EETs (8,9-EET, 11,12-EET and 14,15-EET) for 12, 24, 48 and 72 h, respectively. Cell proliferation was measured using the MTT assay. The effect of exogenous EETs on cell cycle of Tca-8113 cells was assessed by flow cytometry. Signal transduction inhibitors of PI3K (LY294002), MAPKK (PD98059), MAPK (apigenin) and PKC (H7) were used to block EETs-induced cell proliferation. Expressions of the total protein and phosphorylated ERK1/2 and Akt were determined by Western blot. RESULTS: EETs promoted proliferation of tumor cells compared with the control and vehicle group in a dose-and time-dependent manner (P<0.01). Incubation of tumor cells with EETs markedly increased the cell number at S/G2-M phase. The percentages of Tca-8113 cells at S and G2-M phases were (49.7+/-7.5%) vs. (17.2+/-9.7%) (P<0.01) and (21.0+/-5.3%) vs. (4.9+/-7.3%), respectively(P<0.01) with and without the treatment of 11,12-EET. EETs incubation significantly enhanced phosphorylation of MARK as well as PI3K/Akt in tumor cells. LY294002, PD98059, apigenine and H7 reduced the stimulative effect of EETs on cell proliferation. CONCLUSION: EETs possess the promotive effect on proliferation of tumor cells via activation of MAPK and PI3K/Akt signal pathways.

Effective rescue of dystrophin improves cardiac function in dystrophin-deficient mice by a modified morpholino oligomer.

Antisense oligonucleotide-mediated exon skipping is able to correct out-of-frame mutations in Duchenne muscular dystrophy and restore truncated yet functional dystrophins. However, its application is limited by low potency and inefficiency in systemic delivery, especially failure to restore dystrophin in heart. Here, we conjugate a phosphorodiamidate morpholino oligomer with a designed cell-penetrating peptide (PPMO) targeting a mutated dystrophin exon. Systemic delivery of the novel PPMO restores dystrophin to almost normal levels in the cardiac and skeletal muscles in dystrophic mdx mouse. This leads to increase in muscle strength and prevents cardiac pump failure induced by dobutamine stress in vivo. Muscle pathology and function continue to improve during the 12-week course of biweekly treatment, with significant reduction in levels of serum creatine kinase. The high degree of potency of the oligomer in targeting all muscles and the lack of detectable toxicity and immune response support the feasibility of testing the novel oligomer in treating Duchenne muscular dystrophy patients.

Myostatin propeptide gene delivery by adeno-associated virus serotype 8 vectors enhances muscle growth and ameliorates dystrophic phenotypes in mdx mice.

Myostatin has been extensively documented as a negative regulator of muscle growth. Myostatin inhibition is therefore considered an attractive strategy for the treatment of muscle-wasting diseases such as muscular dystrophies. To investigate whether systemic gene delivery of myostatin propeptide (MRPO), a natural inhibitor of myostatin, could enhance body-wide skeletal muscle growth, we used adeno-associated virus serotype 8 (AAV8) vectors to deliver the MRPO gene into either normal mice or mdx mice, a murine model of Duchenne muscular dystrophy (DMD). In normal mice, a significant increase in skeletal muscle mass was observed after either an intraperitoneal injection of AAV-MPRO into neonates, or an intravenous injection of AAV-MPRO76AFc (a modified MPRO fused with IgG Fc) into adults. Enhanced muscle growth occurred because of myofiber hypertrophy, not hyperplasia. In mdx mice, a significant increase in skeletal muscle mass was also observed after AAV-MPRO76AFc injection. The treated mdx mice showed larger and more uniform myofibers, fewer infiltrating mononuclear cells, less fibrosis, and lower serum creatine kinase levels. In addition, a grip force test and an in vitro tetanic contractile force test showed improved muscle strength. A treadmill test, however, showed reduced endurance of the treated mdx mice compared with their untreated counterparts. Importantly, no cardiac hypertrophy was observed in either normal or mdx mice after myostatin inhibition by gene delivery. These results clearly demonstrate the efficacy of AAV8-mediated myostatin propeptide gene delivery in a rodent model of DMD, and warrant further investigation in large animal models and eventually in human patients.

Cytochrome p450 epoxygenase promotes human cancer metastasis.

Cytochrome P450 (CYP) epoxygenases convert arachidonic acid to four regioisomeric epoxyeicosatrienoic acids (EET), which exert diverse biological activities in a variety of systems. We previously reported that the CYP2J2 epoxygenase is overexpressed in human cancer tissues and cancer cell lines and that EETs enhance tumor growth, increase carcinoma cell proliferation, and prevent apoptosis of cancer cells. Herein, we report that CYP epoxygenase overexpression or EET treatment promotes tumor metastasis independent of effects on tumor growth. In four different human cancer cell lines in vitro, overexpression of CYP2J2 or CYP102 F87V with an associated increase in EET production or addition of synthetic EETs significantly induced Transwell migration (4.5- to 5.5-fold), invasion of cells (3- to 3.5-fold), cell adhesion to fibronectin, and colony formation in soft agar. In contrast, the epoxygenase inhibitor 17-ODYA or infection with the antisense recombinant adeno-associated viral vector (rAAV)-CYP2J2 vector inhibited cell migration, invasion, and adhesion with an associated reduction in EET production. CYP overexpression also enhanced metastatic potential in vivo in that rAAV-CYP2J2-infected MDA-MB-231 human breast carcinoma cells showed 60% more lung metastases in athymic BALB/c mice and enhanced angiogenesis in and around primary tumors compared with control cells. Lung metastasis was abolished by infection with the antisense rAAV-CYP2J2 vector. CYP epoxygenase overexpression or EET treatment up-regulated the prometastatic matrix metalloproteinases and CD44 and down-regulated the antimetastatic genes CD82 and nm-23. Together, these data suggest that CYP epoxygenase inhibition may represent a novel approach to prevent metastasis of human cancers.