A novel tumor metastasis suppressor gene LASS2/TMSG1 interacts with vacuolar ATPase through its homeodomain

LASS2/TMSG1 was a novel tumor metastasis suppressor gene, which was first cloned by our laboratory from non‐metastatic and metastatic cancer cell variants of human prostate carcinoma PC‐3M using mRNA differential display in 1999. LASS2/TMSG1 could interact with the C subunit of vacuolar ATPase (V‐ATPase, ATP6V0C) and regulate V‐ATPase activity. In an attempt to provide molecular mechanism of the interaction between LASS2/TMSG1 and V‐ATPase, we constructed four variant transfectants containing different functional domain of LASS2/TMSG1 and stably transfected the variants to human prostate cancer cell line PC‐3M‐1E8 cell with high metastatic potential. Results showed that there were no obvious differences of V‐ATPase expression among different transfected cells and the control. However, V‐ATPase activity and intracellular pH was significantly higher in the variant transfectants with Homeodomain of LASS2/TMSG1 than that in the control using the pH‐dependent fluorescence probe BECEF/AM. Immunoprecipitation, immunofluorescence and immuno‐electron microscope alone or in combination demonstrated the direct interaction of Homeodomain of LASS2/TMSG1 and ATP6V0C. Loss of Homeodomain markedly enhanced the proliferation ability but weakened the apoptotic effect of LASS2/TMSG1 in PC‐3M‐1E8 cells. These lines of results for the first time contribute to the conclusion that LASS2/TMSG1 could regulate V‐ATPase activity and intracellular pH through the direct interaction of its Homeodomain and the C subunit of V‐ATPase. Their interaction could play important roles in the apoptosis of tumor cells. J. Cell. Biochem. 114: 570–583, 2013. © 2012 Wiley Periodicals, Inc.     

Spheroids from adipose‐derived stem cells exhibit an miRNA profile of highly undifferentiated cells

Two‐dimensional (2D) cell cultures have been extensively used to investigate stem cell biology, but new insights show that the 2D model may not properly represent the potential of the tissue of origin. Conversely, three‐dimensional cultures exhibit protein expression patterns and intercellular junctions that are more representative of their in vivo condition. Multiclonal cells that grow in suspension are defined as “spheroids,” and we have previously demonstrated that spheroids from adipose‐derived stem cells (S‐ASCs) displayed enhanced regenerative capability. With the current study, we further characterized S‐ASCs to further understand the molecular mechanisms underlying their stemness properties. Recent studies have shown that microRNAs (miRNAs) are involved in many cellular mechanisms, including stemness maintenance and proliferation, and adipose stem cell differentiation. Most studies have been conducted to identify a specific miRNA profile on adherent adipose stem cells, although little is still known about S‐ASCs. In this study, we investigate for the first time the miRNA expression pattern in S‐ASCs compared to that of ASCs, demonstrating that cell lines cultured in suspension show a typical miRNA expression profile that is closer to the one reported in induced pluripotent stem cells. Moreover, we have analyzed miRNAs that are specifically involved in two distinct moments of each differentiation, namely early and late stages of osteogenic, adipogenic, and chondrogenic lineages during long‐term in vitro culture. The data reported in the current study suggest that S‐ASCs have superior stemness features than the ASCs and they represent the true upstream stem cell fraction present in adipose tissue, relegating their adherent counterparts.     

两株采自惠州的细鞘丝藻亚科(Leptolyngbyaceae)嗜热蓝细菌的分离鉴定及细胞组分分析

【背景】随着CO_2排放增加,全球变暖愈发严峻,嗜热蓝细菌作为能够在45°C及以上环境中生长并实现生物固碳的微生物,具有重要的研究意义。【目的】对从广东惠州地区采集的藻种进行分离鉴定,并筛选出2株嗜热蓝细菌,研究其生长特性,为嗜热蓝细菌的后续应用提供依据。【方法】通过16SrRNA基因、藻蓝蛋白链A基因(PhycoA)序列分析确定从惠州地区采集到的菌株的分类学位置。对PKUAC-GDTS1-24和PKUAC-GDTS1-29两株嗜热蓝细菌进行形态观察和主要细胞成分(灰分、糖类、脂质、蛋白质和色素)分析。【结果】共分离出12株嗜热蓝细菌,其中PKUAC-GDTS1-24和PKUAC-GDTS1-29菌株,形态上呈蓝绿色球形毛状体,是由细胞形成密集的簇,彼此附着形成的。两株嗜热蓝细菌的主要细胞成分是糖类,分别占细胞干重的36.42%和28.46%。PKUAC-GDTS1-24的灰分、脂质和蛋白质含量分别为24.41%、21.40%和26.64%。PKUAC-GDTS1-29的细胞中,灰分、脂质和蛋白质含量分别为24.72%、23.92%和12.93%。藻蓝蛋白(Phycocyanin,PC)在PKUAC-GDTS1-24和PKUAC-GDTS1-29中的含量分别为157.29 mg/g DW和374.86 mg/g DW,类胡萝卜素分别为65.13 mg/g DW和18.87 mg/g DW。【结论】基于系统发育树研究,本实验的2个分离株属于细鞘丝藻亚科(Leptolyngbyaceae),与研究较少的纤发鞘丝蓝细菌属(Leptolyngbya)菌株相近,可能是广东和四川温泉中存在的一种新型丝状轻度嗜热蓝细菌属或Leptolyngbya新种。嗜热菌株PKUAC-GDTS1-24和PKUAC-GDTS1-29的形态和细胞组成相似,通过比较,2个菌株的藻胆蛋白含量远远高于其他研究报道的Leptolyngbya蓝细菌,尤其是PKUAC-GDTS1-29可以作为藻蓝蛋白生产的潜在菌株。     

Evaluation of self-similar features in time series of serum growth hormone and prolactin levels by fractal analysis: Effect of delayed sleep and complexity of diurnal variation

We assayed the diurnal concentrations of growth hormone (GH) and prolactin (PRL) in 6 healthy male volunteers to evaluate the self-similar features in the time series of each hormone on the basis of fractal theory and to determine the fractal dimension as an index of the complexity of the diurnal variation. In addition, we assessed the effects of a 6-hour delay in the sleep period on the complexity of the diurnal variaton of these hormones. There was a statistically significant fractal feature in the serum levels of GH both under the nocturnal-sleep and delayed-sleep conditions in all subjects. The time series of the serum PRL concentrations also showed a statistically significant fractal feature under the nocturnal-sleep and delayed-sleep conditions in all subjects. The fractal dimensions of the patterns of the GH or PRL levels were 1.879 and 1.929 or 1.754 and 1.785 under the nocturnal-sleep and delayed-sleep conditions, respectively. Two-way ANOVA revealed no significant difference in the fractal dimension between the two sleep conditions but did reveal a significant difference between the fractal dimensions of the GH and PRL levels. These results showed (1) that delayed sleep had no significant effect on the complexity of the diurnal pattern of these hormones, and (2) that the diurnal pattern of the GH levels was more complex than that of the PRL levels.     

Targeting to the HIV-1 RRE of the influenza virus NS1 protein effector domain as a potent, specific anti-HIV agent

The Rev axis of HIV autoregulation is one of two critical viral regulatory pathways required for expression of viral genomic and mRNA and for replication. Consequently it is an attractive therapeutic target. Previous studies have investigated the anti-HIV efficacy of targeting to the RRE (the viral RNA target sequence of the Rev axis) a trans-dominant negative inhibitor mutant Rev, M10. In this study we have fused a portion of the influenza virus NS1 protein (which normally inhibits polyA(+) mRNA transport and splicing) to the Rev M10 gene while deleting the NS1 poly(A) binding region. The resulting chimera demonstrates specific and enhanced inhibition of viral-RRE-containing RNA expression.     

Fish-oil supplementation in patients with implantable cardioverter defibrillators: a meta-analysis

Background

A recent Cochrane meta-analysis did not confirm the benefits of fish and fish oil in the secondary prevention of cardiac death and myocardial infarction. We performed a meta-analysis of randomized controlled trials that examined the effect of fish-oil supplementation on ventricular fibrillation and ventricular tachycardia to determine the overall effect and to assess whether heterogeneity exists between trials.

Methods

We searched electronic databases (MEDLINE, EMBASE, The Cochrane Central Register of Controlled Trials, CINAHL) from inception to May 2007. We included randomized controlled trials of fish-oil supplementation on ventricular fibrillation or ventricular tachycardia in patients with implantable cardioverter defibrillators. The primary outcome was implantable cardioverter defibrillator discharge. We calculated relative risk [RR] for outcomes at 1-year follow-up for each study. We used the DerSimonian and Laird random-effects methods when there was significant heterogeneity between trials and the Mantel-Hanzel fixed-effects method when heterogeneity was negligible.

Results

We identified 3 trials of 1–2 years'' duration. These trials included a total of 573 patients who received fish oil and 575 patients who received a control. Meta-analysis of data collected at 1 year showed no overall effect of fish oil on the relative risk of implantable cardioverter defibrillator discharge. There was significant heterogeneity between trials. The second largest study showed a significant benefit of fish oil (relative risk [RR] 0.74, 95% confidence interval [CI] 0.56–0.98). The smallest showed an adverse tendency at 1 year (RR 1.23, 95% CI 0.92–1.65) and significantly worse outcome at 2 years among patients with ventricular tachycardia at study entry (log rank p = 0.007).

Conclusion

These data indicate that there is heterogeneity in the response of patients to fish-oil supplementation. Caution should be used when prescribing fish-oil supplementation for patients with ventricular tachycardia.There is a public perception that fish and fish oil can be recommended uniformly for the prevention of coronary artery disease.^1–3 However, the scientific evidence is divided^4,5 and official agencies have called for more research.⁶It is estimated that 0.5% of patients with coronary heart disease, 1% of patients with diabetes or hypertension and 2% of the general population at low risk of coronary heart disease take fish-oil supplements.⁷ In 2004, the price of fish oils overtook that of vegetable oils, and in 2006, the price rose to US$750 per ton.⁸ The value of fish oil as a nutraceutical in the European market was US$194 million in 2004, and it is anticipated that the price will continue to rise as availability declines.⁸ Canada is both a consumer and an exporter of fish oil, and it exported 15 000 tons in 2006.⁹The scientific debate over the clinical value of fish oil is highlighted by a recent Cochrane review, which concluded that long-chain omega-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid) had no clear effect on total mortality, combined cardiovascular events or cancer.⁴ Furthermore, another recent meta-analysis¹⁰ only showed a significant positive association between fish-oil consumption and prevention of restenosis after coronary angioplasty in a select subgroup after excluding key negative papers.¹¹ Finally, the antiarrhythmic effect, which is proposed to be the principal mechanism of their benefit in cardiovascular disease, has not been demonstrated clearly in clinical trials.^12–14We therefore performed a meta-analysis of randomized controlled trials that examined the effect of fish-oil supplementation in patients with implantable cardioverter defibrillators who are at risk of ventricular arrhythmia to determine the overall effect of fish oils. We also sought to investigate whether there was significant heterogeneity between trials.