豹蛙核酸酶与斑蝥酸钠对肺腺癌细胞增殖的协同抑制作用

豹蛙核酸酶(onconase,Onc)是从美洲北方豹蛙卵母细胞中提取的一种核糖核酸酶,对许多肿瘤细胞都具有杀伤作用。斑蝥素(cantharidin)是存在于芫青科昆虫斑蝥体内的一种天然防御性毒素,斑蝥酸钠(sodium cantharidate,SCA)是斑蝥素半合成衍生物。鉴于Onc与SCA对非小细胞肺癌都具有杀伤作用,采用MTT法测定Onc与SCA单独与联合作用于两株肺腺癌细胞的IC50值,运用联合作用指数(combination index,CI)和等效线分析评价两者联合作用的效果。结果表明,Onc与SCA联合作用时,CI值均小于0.7,等效线分析图显示,代表Onc与SCA联合作用的点均位于加成线下方,Onc与SCA对肺腺癌SPC-A-1、A549细胞株增殖的抑制作用具有协同效应。用流式细胞仪进行的凋亡细胞检测结果也支持上述"Onc/SCA联合使用具有协同抗癌作用"的结论。     

Tea Consumption and Cognitive Impairment: A Cross-Sectional Study among Chinese Elderly

Background

Laboratorial and epidemiological researches suggested that tea exhibited potential neuroprotective effect which may prevent cognitive impairment, but there were few data among the elderly aged 60 years and above in China.

Objective

The objective was to explore the relationship between characteristics of tea consumption and cognitive impairment.

Design

We analyzed the baseline data from Zhejiang Major Public Health Surveillance Program (ZPHS) which was conducted in 2014. Totally 9,375 residents aged 60 years and above were recruited in this study. Face-to-face interview based on a self-developed questionnaire was performed for each participant. Detailed tea consumption habits were included in the questionnaire. Cognitive impairment screening was performed by using Mini-Mental State Examination (MMSE). Education-specific cut-off points for Chinese were applied to determine the status of cognitive impairment. Logistic regression analysis was used to calculate odds ratios (ORs) of cognitive impairment associated with tea consumption.

Results

The means (SD) of MMSE scores for the subjects who did not consume tea and consumed <2 cups/d, 2–4 cups/d, ≥4 cups/d were 23.3 (SD = 5.61), 23.8 (SD = 5.60), 24.5 (SD = 5.63) and 25.0 (SD = 5.08), respectively. An inverse correlation was found between tea consumption (of all types) and prevalence of cognitive impairment. Volume of tea consumption was significantly associated with cognitive impairment: compared with non-consumption participants, those who consumed < 2 cups/d, 2–4 cups/d, and ≥4 cups/d were observed ORs of 0.77 (95% CI: 0.56, 1.07), 0.62 (95% CI: 0.47, 0.81), and 0.49 (95% CI: 0.36, 0.66), respectively. Compared with non-consumption, black tea presented a positive correlation with cognitive function after controlling for potential confounders (OR = 0.52, 95% CI: 0.28, 0.95), while green tea showed no significant difference (OR = 1.04, 95% CI: 0.72, 1.51). Participants who consumed weak tea, moderate tea or strong tea more often were observed a better cognitive status when compared with those who did not have tea, with an OR of 0.51 (95% CI: 0.28, 0.92), 0.32 (95% CI: 0.19, 0.56) and 0.42 (95% CI: 0.22, 0.78) after adjusting for the potential confounders. But there was no statistically significant difference between any two of these ORs.

Conclusion

Black tea consumption was association with better cognitive performance among the elderly aged 60 years and above in China, while green tea presented no correlation. The positive association of cognitive status with tea consumption was not limited to particular type of concentration.     

Diurnal Expression Pattern,Allelic Variation,and Association Analysis Reveal Functional Features of the E1 Gene in Control of Photoperiodic Flowering in Soybean

Although four maturity genes, E1 to E4, in soybean have been successfully cloned, their functional mechanisms and the regulatory network of photoperiodic flowering remain to be elucidated. In this study, we investigated how the diurnal expression pattern of the E1 gene is related to photoperiodic length; and to what extent allelic variation in the B3-like domain of the E1 gene is associated with flowering time phenotype. The bimodal expression of the E1 gene peaked first at around 2 hours after dawn in long-day condition. The basal expression level of E1 was enhanced by the long light phase, and decreased by duration of dark. We identified a 5bp (3 SNP and 2-bp deletion) mutation, referred to an e1-b3a, which occurs in the middle of B3 domain of the E1 gene in the early flowering cultivar Yanhuang 3. Subcellular localization analysis showed that the putative truncated e1-b3a protein was predominately distributed in nuclei, indicating the distribution pattern of e1-b3a was similar to that of E1, but not to that of e1-as. Furthermore, genetic analysis demonstrated allelic variations at the E1 locus significantly underlay flowering time in three F₂ populations. Taken together, we can conclude the legume specific E1 gene confers some special features in photoperiodic control of flowering in soybean. Further characterization of the E1 gene will extend our understanding of the soybean flowering pathway in soybean.     

Bufalin Reverses Resistance to Sorafenib by Inhibiting Akt Activation in Hepatocellular Carcinoma: The Role of Endoplasmic Reticulum Stress

Sorafenib is the standard first-line therapeutic treatment for patients with advanced hepatocellular carcinoma (HCC), but its use is hampered by the development of drug resistance. The activation of Akt by sorafenib is thought to be responsible for this resistance. Bufalin is the major active ingredient of the traditional Chinese medicine Chan su, which inhibits Akt activation; therefore, Chan su is currently used in the clinic to treat cancer. The present study aimed to investigate the ability of bufalin to reverse both inherent and acquired resistance to sorafenib. Bufalin synergized with sorafenib to inhibit tumor cell proliferation and induce apoptosis. This effect was at least partially due to the ability of bufalin to inhibit Akt activation by sorafenib. Moreover, the ability of bufalin to inactivate Akt depended on endoplasmic reticulum (ER) stress mediated by inositol-requiring enzyme 1 (IRE1). Silencing IRE1 with siRNA blocked the bufalin-induced Akt inactivation, but silencing eukaryotic initiation factor 2 (eIF2) or C/EBP-homologous protein (CHOP) did not have the same effect. Additionally, silencing Akt did not influence IRE1, CHOP or phosphorylated eIF2α expression. Two sorafenib-resistant HCC cell lines, which were established from human HCC HepG2 and Huh7 cells, were refractory to sorafenib-induced growth inhibition but were sensitive to bufalin. Thus, Bufalin reversed acquired resistance to sorafenib by downregulating phosphorylated Akt in an ER-stress-dependent manner via the IRE1 pathway. These findings warrant further studies to examine the utility of bufalin alone or in combination with sorafenib as a first- or second-line treatment after sorafenib failure for advanced HCC.     

Downregulation of TNIP1 Expression Leads to Increased Proliferation of Human Keratinocytes and Severer Psoriasis-Like Conditions in an Imiquimod-Induced Mouse Model of Dermatitis

Psoriasis is a chronic, inflammatory skin disease involving both environmental and genetic factors. According to genome-wide association studies (GWAS), the TNIP1 gene, which encodes the TNF-α–induced protein 3-interacting protein 1 (TNIP1), is strongly linked to the susceptibility of psoriasis. TNIP1 is a widely expressed ubiquitin sensor that binds to the ubiquitin-editing protein A20 and restricts TNF- and TLR-induced signals. In our study, TNIP1 expression decreased in specimens of epidermis affected by psoriasis. Based on previous studies suggesting a role for TNIP1 in modulating cancer cell growth, we investigated its role in keratinocyte proliferation, which is clearly abnormal in psoriasis. To mimic the downregulation or upregulation of TNIP1 in HaCaT cells and primary human keratinocytes (PHKs), we used a TNIP1 specific small interfering hairpin RNA (TNIP1 shRNA) lentiviral vector or a recombinant TNIP1 (rTNIP1) lentiviral vector, respectively. Blocking TNIP1 expression increased keratinocyte proliferation, while overexpression of TNIP1 decreased keratinocyte proliferation. Furthermore, we showed that TNIP1 signaling might involve extracellular signal-regulated kinase1/2 (Erk1/2) and CCAAT/enhancer-binding protein β (C/EBPβ) activity. Intradermal injection of TNIP1 shRNA in BALB/c mice led to exaggerated psoriatic conditions in imiquimod (IMQ)-induced psoriasis-like dermatitis. These findings indicate that TNIP1 has a protective role in psoriasis and therefore could be a promising therapeutic target.     

A Sweetpotato Geranylgeranyl Pyrophosphate Synthase Gene,IbGGPS, Increases Carotenoid Content and Enhances Osmotic Stress Tolerance in Arabidopsis thaliana

Sweetpotato highly produces carotenoids in storage roots. In this study, a cDNA encoding geranylgeranyl phyrophosphate synthase (GGPS), named IbGGPS, was isolated from sweetpotato storage roots. Green fluorescent protein (GFP) was fused to the C-terminus of IbGGPS to obtain an IbGGPS-GFP fusion protein that was transiently expressed in both epidermal cells of onion and leaves of tobacco. Confocal microscopic analysis determined that the IbGGPS-GFP protein was localized to specific areas of the plasma membrane of onion and chloroplasts in tobacco leaves. The coding region of IbGGPS was cloned into a binary vector under the control of 35S promoter and then transformed into Arabidopsis thaliana to obtain transgenic plants. High performance liquid chromatography (HPLC) analysis showed a significant increase of total carotenoids in transgenic plants. The seeds of transgenic and wild-type plants were germinated on an agar medium supplemented with polyethylene glycol (PEG). Transgenic seedlings grew significantly longer roots than wild-type ones did. Further enzymatic analysis showed an increased activity of superoxide dismutase (SOD) in transgenic seedlings. In addition, the level of malondialdehyde (MDA) was reduced in transgenics. qRT-PCR analysis showed altered expressions of several genes involved in the carotenoid biosynthesis in transgenic plants. These data results indicate that IbGGPS is involved in the biosynthesis of carotenoids in sweetpotato storage roots and likely associated with tolerance to osmotic stress.     

Identification and characterization of a novel salt‐tolerant esterase from a Tibetan glacier metagenomic library

A salt‐tolerant esterase, designated H9Est, was identified from a metagenomic library of the Karuola glacier. H9Est gene comprised 1071 bp and encoded a polypeptide of 357 amino acids with a molecular mass of 40 kDa. Sequence analysis revealed that H9Est belonged to the family IV of bacterial lypolitic enzyme. H9Est was overexpressed in Escherichia coli and the purified enzyme showed hydrolytic activity towards p‐nitrophenyl esters with carbon chain from 2 to 8. The optimal esterase activity was at 40°C and pH 8.0 and the enzyme retained its activity towards some miscible organic solvents such as polyethylene glycol. A three‐dimensional model of H9Est revealed that S200, D294, and H324 formed the H9Est catalytic triad. Circular Dichroism spectra and molecular dynamic simulation indicated that the esterase had a wide denaturation temperature range and flexible loops that would be beneficial for H9Est performance at low temperatures while retaining heat‐resistant features. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:890–899, 2015