Cloning and expression analysis of squalene synthase, a key enzyme involved in antifungal steroidal glycoalkaloids biosynthesis from Solanum nigrum

Steroidal glycoalkaloids (SGAs) are a family of nitrogenous secondary metabolites produced in solanaceous plants. In our present study, γ-solamargine and its aglycone solasodine from Solanum nigrum were found to inhibit hyphae formation of Fusarium oxysporum. As phytoalexins, the formation of SGAs was significantly increased in the plants when infected with the spore of F. oxysporum. In order to understand this inducible defense mechanism, the rate-limiting enzyme squalene synthase in the biosynthesis process of SGAs was investigated well. A full-length cDNA encoding squalene synthase was isolated from S. nigrum (the squalene synthase in S. nigrum was designated as SnSS). The full-length cDNA of SnSS was 1,765 bp and contained a 1,236 bp open reading frame (ORF) encoding a polypeptide of 411 amino acids. Bioinformatic analysis revealed that the deduced SnSS protein had a high similarity with other plant squalene synthases. Real-time RT-PCR analysis showed that SnSS was expressed constitutively in all tested tissues, with the highest expression in stems. After treatment with the spore of F. oxysporum, the mRNA level of SnSS was significantly increased in the infected plants in accordance with the change of SGAs.

Production and crystallization of the C-propeptide trimer from human procollagen III

The C-propeptide domains of the fibrillar procollagens, which are present throughout the Metazoa in the form of ∼90 kDa trimers, play crucial roles in both intracellular molecular assembly and extracellular formation of collagen fibrils. The first crystallization of a C-propeptide domain, that from human procollagen III, is described. Following transient expression in mammalian 293T cells of both the native protein and a selenomethionine derivative, two crystal forms of the homotrimer were obtained: an orthorhombic form (P2(1)2(1)2(1)) that diffracted to 1.7 Å resolution and a trigonal form (P321) that diffracted to 3.5 Å resolution. Characterization by MALDI-TOF mass spectrometry allowed the efficiency of selenomethionine incorporation to be determined.

Polymorphisms in the SLC11A1 gene and tuberculosis risk: a meta-analysis update

BACKGROUND

Polymorphisms in SLC11A1 gene have been extensively studied for an association with tuberculosis (TB); however, results from replication studies have been inconsistent.

OBJECTIVE

To comprehensively evaluate the genetic risk of polymorphisms (D543N, 3'UTR TGTG ins/del, INT4, [GT]n) in the SLC11A1 gene for TB.

METHODS

A meta-analysis was carried out to analyse the association between SLC11A1 polymorphisms and TB risk.

RESULTS

A total of 82 case-control studies in 35 articles were included in the meta-analysis. The results showed that these four polymorphisms were associated with an increased risk of TB (D543N OR 1.31, 95%CI 1.11-1.55; 3'UTR TGTG ins/del OR 1.45, 95%CI 1.25-1.68; INT4 OR 1.27, 95%CI 1.09-1.49; [GT]n OR 1.35, 95%CI 1.14-1.61). In further stratified analyses by ethnicity and TB forms, significant increased risks were found in subgroups of Asians and in pulmonary TB (PTB) for all four polymorphisms, while an increased risk of extra-pulmonary TB (EPTB) was found for D543N polymorphism.

CONCLUSIONS

This meta-analysis suggests that polymorphisms in the SLC11A1 gene contribute to TB (both PTB and EPTB), particularly in Asians.

Interplay between mesenchymal stem cells and lymphocytes: implications for immunotherapy and tissue regeneration

In addition to their potential for replacing damaged and diseased tissues by differentiating into tissue-specific cells, mesenchymal stem cells (MSCs) have been found to interact closely with immune cells, such as lymphocytes. In this review, we will discuss current research regarding the immunomodulatory properties of MSCs and the effects of lymphocytes on MSCs. We will suggest how these findings could be translated to potential clinical treatment. MSCs can regulate immune response by inducing activated T-cell apoptosis through the FAS ligand (FASL)/FAS-mediated death pathway via cell-cell contact, leading to up-regulation of regulatory T-cells (Tregs), which ultimately results in immune tolerance. Conversely, lymphocytes can impair survival and osteogenic differentiation of implanted MSCs by secreting the pro-inflammatory cytokines IFN-γ and TNF-α and/or through the FASL/FAS-mediated death pathway, thereby negatively affecting MSC-mediated tissue regeneration. One novel strategy to improve MSC-based tissue engineering involves the reduction of IFN-γ and TNF-α concentration by systemic infusion of Tregs or local application of aspirin. Further understanding of the mechanisms underlying the interplay between lymphocytes and MSCs may be helpful in the development of promising approaches to improve cell-based regenerative medicine and immune therapies.

Targeting Cullin-RING ligases by MLN4924 induces autophagy via modulating the HIF1-REDD1-TSC1-mTORC1-DEPTOR axis

MLN4924, a newly discovered small molecule inhibitor of NEDD8-activating enzyme (NAE), inactivates Cullin-RING E3 ubiquitin Ligases (CRLs) by blocking cullin neddylation. As a result, MLN4924 causes accumulation of several key substrates of CRLs and effectively suppresses tumor cell growth by inducing apoptosis and senescence. However, the role of MLN4924 in induction of autophagy and its biological significance are totally unknown. Here we showed that MLN4924 effectively induces autophagy in both time- and dose-dependent manners in multiple human cancer lines, indicating a general phenomenon. Mechanistically, by inactivating CRLs, MLN4924 causes accumulation of DEPTOR and HIF1α. The siRNA knockdown and gene KO studies showed that DEPTOR and the HIF1-REDD1-TSC1 axis are responsible for MLN4924-induced autophagy via inhibiting mTORC1. Biologically, autophagy is a survival signal to tumor cells, and blockage of autophagy via siRNA knockdown, gene KO and small molecule inhibitor remarkably enhanced MLN4924-induced apoptosis. Our study reveals an uncharacterized mechanism of MLN4924 action and provides the proof-of-concept evidence for strategic drug combination of MLN4924 with an autophagy inhibitor for maximal killing of tumor cells via enhancing apoptosis.

Combined performance of physical examination, mammography, and ultrasonography for breast cancer screening among Chinese women: a follow-up study

OBJECTIVE

We aimed to determine which combination of physical examination (pe), mammography (mam), and ultrasonography (us) would optimize breast cancer detection in China.

METHODS

We conducted a trial of screening with pe, mam, and us among Chinese women 25 years of age and older. All initial screenings using the three modalities were completed within 30 days of each other, and subjects were followed approximately 1 year later. The performances of the three screening methods used alone, in parallel, or in series were compared. Data were analyzed using exact confidence intervals (cis) and the McNemar test.

RESULTS

Between March 2009 and July 2011, 3028 eligible women completed all study examinations. At a mean follow-up of 1.3 years, 33 breast cancers were identified in the study population. Mammography detected 28 cancers; us, 24 cancers; and pe, 22 cancers. During the follow-up period, 2 false-negative cases occurred clinically. The highest sensitivity for breast cancer screening (93.9%) was achieved by paralleling mam with us, but came at the cost of a higher recall rate (12.15%). Using us alone at the first stage, followed by mam when indicated, offered high specificity (99.4%) and the lowest recall rate (1.82%), which were not reached at the expense of sensitivity (84.8%). Used in series, us and mam achieved a sensitivity similar to that for the same modalities used in parallel (McNemar p > 0.05).

CONCLUSIONS

Taking limited health resources into consideration, the strategy of screening with us alone at the first stage, followed by mam when indicated, may optimize breast cancer detection in most regions of China.

Fas ligand regulates the immunomodulatory properties of dental pulp stem cells

Dental pulp stem cells (DPSCs) possess immunoregulatory properties, but the underlying mechanism is not fully understood. Here we showed that DPSCs were capable of inducing activated T-cell apoptosis in vitro and ameliorating inflammatory-related tissue injuries when systemically infused into a murine colitis model. Mechanistically, DPSC-induced immunoregulation was associated with the expression of Fas ligand (FasL), a transmembrane protein that plays an important role in inducing the Fas apoptotic pathway. Knockdown of FasL expression by siRNA in DPSCs reduced their capacity to induce T-cell apoptosis in vitro and abolished their therapeutic effects in mice with colitis. However, the expression level of FasL did not affect either DPSC proliferation rate or multipotent differentiation potential. In summary, FasL governs the immunoregulatory property of DPSCs in the context of inducing T-cell apoptosis.

Altered angiogenesis gene expression in gastrointestinal stromal tumors: potential use in diagnosis, outcome prediction, and treatment

Gastrointestinal stromal tumors (GISTs) occur in diverse locations of the gastrointestinal system. We studied the pathogenesis of GIST by measurement of microvascular density (MVD) and expression of nine signal transduction molecules that have known roles in diverse types of cancers (PI3K, Akt, pTEN, uPA, MMP2, MMP9, HIF1, NOS2, and VEGF) in the tumorous tissues and adjacent normal tissues of 124 GIST patients. We also compared the MVD (a measure of angiogenesis) in tumorous and adjacent normal tissues. Our results indicated significant differences in the expression of the assayed mRNAs and proteins in GIST cells and in adjacent normal cells. In addition, tumorous tissues had significantly higher MVD than adjacent normal tissues. These nine genes have potential for use for diagnosis, outcome prediction, and as new targeted treatments for GISTs.

Distinct and overlapping functional roles of Src family kinases in mouse platelets

BACKGROUND AND OBJECTIVES

Src family kinases (SFKs) play a critical role in initiating and propagating signals in platelets. The aims of this study were to quantitate SFK members present in platelets and to analyze their contribution to platelet regulation using glycoprotein VI (GPVI) and intregrin αIIbβ3, and in vivo.

METHODS AND RESULTS

Mouse platelets express four SFKs, Fgr, Fyn, Lyn and Src, with Lyn expressed at a considerably higher level than the others. Using mutant mouse models, we demonstrate that platelet activation by collagen-related peptide (CRP) is delayed and then potentiated in the absence of Lyn, but only marginally reduced in the absence of Fyn or Fgr, and unaltered in the absence of Src. Compound deletions of Lyn/Src or Fyn/Lyn, but not of Fyn/Src or Fgr/Lyn, exhibit a greater delay in activation relative to Lyn-deficient platelets. Fibrinogen-adherent platelets show reduced spreading in the absence of Src, potentiation in the absence of Lyn, but no change in the absence of Fyn or Fgr. In mice double-deficient in Lyn/Src or Fgr/Lyn, the inhibitory role of Lyn on spreading on fibrinogen is lost. Lyn is the major SFK-mediating platelet aggregation on collagen at arterial shear and its absence leads to a reduction in thrombus size in a laser injury model.

CONCLUSION

These results demonstrate that SFKs share individual and overlapping roles in regulating platelet activation, with Lyn having a dual role in regulating GPVI signaling and an inhibitory role downstream of αIIbβ3, which requires prior signaling through Src.

A phase I, open-label dose-escalation study of continuous treatment with BIBF 1120 in combination with paclitaxel and carboplatin as first-line treatment in patients with advanced non-small-cell lung cancer

BACKGROUND

BIBF 1120 is an oral potent inhibitor of vascular endothelial growth factor receptor, fibroblast growth factor receptor and platelet-derived growth factor receptor, the three key receptor families involved in angiogenesis. This phase I, open-label dose-escalation study investigated BIBF 1120 combined with paclitaxel (Taxol) and carboplatin in first-line patients with advanced (IIIB/IV) non-small-cell lung cancer.

PATIENTS AND METHODS

Patients received BIBF 1120 (starting dose 50 mg b.i.d.) on days 2-21 and paclitaxel (200 mg/m2) and carboplatin [area under curve (AUC)=6 mg/ml/min] on day 1 of each 21-day cycle. Primary end points were safety and BIBF 1120 maximum tolerated dose (MTD) in this combination. Pharmacokinetics (PK) profiles were evaluated.

RESULTS

Twenty-six patients were treated (BIBF 1120 50-250 mg b.i.d.). BIBF 1120 MTD was 200 mg b.i.d. in combination with paclitaxel and carboplatin. Six dose-limiting toxicity events occurred during treatment cycle 1 (liver enzyme elevations, thrombocytopenia, abdominal pain, and rash). Best responses included 7 confirmed partial responses (26.9%); 10 patients had stable disease. BIBF 1120 200 mg b.i.d. had no clinically relevant influence on the PK of paclitaxel 200 mg/m2 and carboplatin AUC 6 mg/ml/min and vice versa.

CONCLUSIONS

BIBF 1120 MTD was 200 mg b.i.d when given with paclitaxel and carboplatin; this combination demonstrated an acceptable safety profile. No relevant changes in PK parameters of the backbone chemotherapeutic agents or BIBF 1120 were observed.

A 48-week study of amlodipine plus amiloride / hydrochlorothiazide vs. amlodipine plus telmisartan in the treatment of hypertension

Background:  Chinese Hypertension Intervention Efficacy (CHIEF) study is a large-scale randomised clinical trial across China, which compares the efficacy of two combination regimens in reducing cardiovascular events associated with hypertension. Methods:  We reported the 48-week efficacy and tolerability of the two antihypertensive regimens in participants from Shandong Province, China. Eligible patients aged 50-79 years were randomised to receive amlodipine plus amiloride/hydrochlorothiazide (Group A) or amlodipine plus telmisartan (Group B). The doses of both regimens were titrated and other antihypertensive agents were added subsequently to achieve a blood pressure (BP) goal (<140/90 mmHg for general population, <130/80 mmHg for diabetics and <150/90 mmHg for elderly). Efficacy variables included the changes of BP, control rates (the proportion of patients achieving a BP goal), and response rates (the proportion of patients achieving a BP goal or a reduction of BP ≥20/10 mmHg). Safety was assessed by monitoring the incidence of adverse events (AEs). Results:  Of the 349 patients enrolled, 314 were randomised and 291 completed the study (141 in Group A and 150 in Group B). At week 48, the BP was reduced by 28.77/15.55 mmHg in Group A and by 31.38/16.07 mmHg in Group B (p > 0.05 for comparisons between Group A and Group B). The control rates (71.79% vs. 77.22%; p = 0.270) and response rates (79.49% vs. 84.81%; p = 0.218) were also similar. For both regimens, the control rates in diabetic patients were relatively lower (31.91% and 32.50%), while those in elderly patients were pretty higher (90.74% and 97.62%). AEs were mild to moderate in severity (17.95% vs. 12.66%, p = 0.193). Conclusion:  Both combination regimens, amlodipine plus amiloride/hydrochlorothiazide and amlodipine plus telmisartan, were effective and safe for the high-risk hypertensive patients.

MiR-181a confers resistance of cervical cancer to radiation therapy through targeting the pro-apoptotic PRKCD gene

The purpose of this study was to define the roles of miR-181a in determining sensitivity of cervical cancer to radiation therapy, to explore the underlying mechanism and to evaluate the potential of miR-181a as a biomarker for predicting radio-sensitivity. Tumor specimens from 18 patients with a histological diagnosis of squamous cervical carcinoma (stage IIIB) were used in the micro-RNA profiling and comparison. These patients never received any chemotherapy before radiation therapy. Human cervical cancer cell lines, SiHa and Me180, were used in vitro (cell culture) and in vivo (animal) studies. Transfection of tumor cells with the mimic or inhibitor of miR-181a, and reporter gene assay, were performed to investigate the role of miR-181a in determining radio-sensitivity and the target gene. Higher expression of miR-181a was observed in human cervical cancer specimens and cell lines that were insensitive to radiation therapy, as compared with sensitive cancer specimens and the cell lines. We also found that miR-181a negatively regulated the expression of PRKCD, a pro-apoptotic protein kinase, via targeting its 3'-untranslated region (UTR), thereby inhibiting irradiation-induced apoptosis and decreasing G2/M block. The role of miR-181a in conferring cellular resistance to radiation treatment was validated both in cell culture models and in mouse tumor xenograft models. The effect of miR-181a on radio-resistance was mediated through targeting the 3'-UTR of PRKCD gene. Thus, the expression level of miR-181a in cervical cancer may serve as a biomarker for sensitivity to radiation therapy, and targeting miR-181a may represent a new approach to sensitizing cervical cancer to radiation treatment.

Unusual localization and translocation of TRPV4 protein in cultured ventricular myocytes of the neonatal rat

TRPV4 protein forms a Ca²⁺-permeable channel that is sensitive to osmotic and mechanical stimuli and responds to warm temperatures, and expresses widely in various kinds of tissues. As for cardiac myocytes, TRPV4 has been detected only at the mRNA level and there were few reports about subcel-lular localization of the protein. The purpose of the present study was to investigate the expression profile of TRPV4 protein in cultured neonatal rat ventricular myocytes. Using Western blots, immunofluorescence, confocal microscopy and immuno-electron microscopy, we have shown that TRPV4 protein was predominantly located in the nucleus of cultured neonatal myocytes. Furthermore, cardiac myocytes responded to hypotonic stimulation by translocating TRPV4 protein out of the nucleus. The significance and mechanism concerning the unusual distribution and translocation of TRPV4 protein in cardiac myocytes remain to be clarified.

Ex vivo expansion of normal and chronic myeloid leukemic stem cells without functional alteration using a NUP98HOXA10homeodomain fusion gene

HOX genes have been implicated as regulators of normal and leukemic stem cell functionality, but the extent to which these activities are linked is poorly understood. Previous studies revealed that transduction of primitive mouse hematopoietic cells with a NUP98HOXA10homeodomain (NA10HD) fusion gene enables a subsequent rapid and marked expansion in vitro of hematopoietic stem cell numbers without causing their transformation or deregulated expansion in vivo. To determine whether forced expression of NA10HD in primitive human cells would have a similar effect, we compared the number of long-term culture-initiating cells (LTC-ICs) present in cultures of lenti-NA10HD versus control virus-transduced CD34(+) cells originally isolated from human cord blood and chronic phase (CP) chronic myeloid leukemia (CML) patients. We found that NA10HD greatly increases outputs of both normal and Ph(+)/BCR-ABL(+) LTC-ICs, and this effect is particularly pronounced in cultures containing growth factor-producing feeders. Interestingly, NA10HD did not affect the initial cell cycle kinetics of the transduced cells nor their subsequent differentiation. Moreover, immunodeficient mice repopulated with NA10HD-transduced CP-CML cells for more than 8 months showed no evidence of altered behavior. Thus, NA10HD provides a novel tool to enhance both normal and CP-CML stem cell expansion in vitro, without apparently altering other properties.