SIRT1 RNAi knockdown induces apoptosis and senescence, inhibits invasion and enhances chemosensitivity in pancreatic cancer cells

The NAD(+)-dependent deacetylase, sirtuin 1 (SIRT1), has been recently been suspected to have a role in tumorigenesis. We investigated the expression of SIRT1 in pancreatic cancer and the effect of SIRT1-targeted RNA interference (RNAi) on cell proliferation and tumor formation in a pancreatic cancer cell line, PANC1. The expression of SIRT1 was investigated in 49 specimens of pancreatic cancer and adjacent normal pancreatic tissues. SIRT1 was overexpressed in pancreatic cancer tissues at both the mRNA and protein levels, with increased SIRT1 positivity associated with tumors from patients over 60 years old, tumors larger than 4 cm, higher TNM (extent of tumor (T), the extent of spread to lymph nodes (N), and presence of distant metastasis (M)) stage or the presence of lymph node or hepatic metastases. The PANC-1 was stably transfected with a SIRT1 small hairpin RNA (shRNA) expression plasmid and compared with untransfected and PANC-1-negative RNAi cells. Proliferation of PANC-1-SIRT1-RNAi cells was significantly reduced, accompanied by increased rates of apoptosis, G1 arrest and senescence. Furthermore, FOXO3a expression was markedly upregulated in PANC-1-SIRT1-RNAi cells, but no significant difference in p53 expression was observed. The invasive ability of PANC-1-SIRT1-RNAi cells was markedly reduced in vitro, which was linked to increased E-cadherin and reduced-MMP expression. Additionally, PANC-1-SIRT1-RNAi cells had a significantly reduced capacity to form tumors in vivo compared with untransfected and PANC-1-negative RNAi cells. These results suggest that SIRT1 may promote cell proliferation and tumor formation in pancreatic cancer, and downregulation of SIRT1 using shRNA could provide a novel therapeutic treatment.

Outbreak Investigation of NADC30-Like PRRSV in South-East China

Epidemiological outbreak investigations were conducted on NADC30-like porcine reproductive and respiratory syndrome virus (PRRSV) to investigate the prevalence of the disease in south-east China in 2015. Two more provinces were found to have NADC30-like PRRSV circulating besides previously reported six provinces. Phylogenetic analysis showed that these virus isolates were clustered in an independent branch and shared high nucleotide similarity to NADC30, a type 2 PRRSV that has been isolated in Unite States in 2008. One NADC30-like PRRSV strain from Henan province was successfully isolated on porcine alveolar macrophages and was tested on 6-week-old specific pathogen-free pigs for pathogenic study. The virus-inoculated pigs showed typical PRRSV clinical symptoms, but all pigs survived throughout the study with a period of 14 days. At necropsy, the lungs of infected pigs developed PRRSV-specific interstitial pneumonia, and virus antigen was detected in lung samples. Therefore, our results indicated NADC30-like PRRSV has widely spread in China and could cause clinical disease on pigs.

The serine-rich Entamoeba histolytica protein is a phosphorylated membrane protein containing O-linked terminal N-acetylglucosamine residues

Previously, we described the isolation of a cDNA clone and the gene encoding a protective antigen of the protozoan parasite Entamoeba histolytica, the serine-rich Entamoeba histolytica protein (SREHP). The derived amino acid sequence of the SREHP cDNA clone was remarkable for a high serine content (52/233 amino acids), a putative signal sequence, multiple hydrophilic dodecapeptide and octapeptide tandem repeats, and a hydrophobic C-terminal putative membrane-spanning region. Here, we show that SREHP is modified by the addition of phosphate at serine residues, O-linked terminal N-acetylglucosamine residues, and by acylation. When the SREHP gene is expressed in baculovirus transformed Sf-9 cells, the product is also phosphorylated and glycosylated and is localized to the plasma membrane of the insect cells. The native SREHP molecule also serves as a potent chemoattractant for amebic trophozoites. The data presented here suggest that SREHP is a unique membrane protein with phosphorylation and glycosylation patterns usually associated with nuclear or cytoplasmic proteins.

Approaching the in vitro clinical trial: engineering organs on chips

In vitro cell culture and animal models are the most heavily relied upon tools of the pharmaceutical industry. When these tools fail, the results are costly and have at times, proven deadly. One promising new tool to enhance preclinical development of drugs is Organs on Chips (OOCs), proposed as a clinically and physiologically relevant means of modeling health and disease. Bringing the patient from bedside to bench in this form requires that the design, build, and test of OOCs be founded in clinical observations and methods. By creating OOCs as models of the patient, the industry may be better positioned to evaluate medicinal therapeutics.

Effect of different alcohols on stratum corneum kallikrein 5 and phospholipase A2 together with epidermal keratinocytes and skin irritation

OBJECTIVES

The aim of this exploratory study was to investigate the effect of ethanol, isopropanol and n-propanol on stratum corneum (SC) enzymes and keratinocytes in vitro together with their effects on skin condition and function.

METHODS

Activities of kallikrein 5 (KLK5) and phospholipase A2 (PLA2) as well as keratinocyte metabolic activity, interleukin-1α (IL-1α) and tumor necrosis factor-α (TNF-α) were measured in vitro in the presence and absence of the different alcohols. We also measured transepidermal water loss (TEWL), skin capacitance, visual dryness and visual redness on the volar forearms of 25 Caucasian women following application of the alcohols 20 and 100 times per day over a period of 14 days in a clinical study.

RESULTS

Reduced activities of KLK5 and PLA2 were observed in the presence of the alcohols. The greatest denaturing effect was always observed for n-propanol (P < 0.001), and in the case of PLA2, the effect of isopropanol was greater than ethanol (P < 0.001). Equally, ethanol had the mildest effects on keratinocyte metabolic activity and cytokine secretion (P < 0.001) and n-propanol always produced the most severe changes in normal and differentiated keratinocytes. These in vitro findings supported the clinical results where the major effects were on the induction of skin irritation (increased dropout rates) and ranked the intolerance of the different alcohols as follows: n-propanol > isopropanol > ethanol. At the high application frequencies, the effect of the different alcohols on transepidermal water loss (TEWL) and skin capacitance was similar, but at the low application frequencies, n-propanol had a significant effect on TEWL and capacitance values (P < 0.05). Equally, n-propanol and isopropanol produced significantly more skin redness at the low application frequencies.

CONCLUSIONS

Clearly, isopropanol and n-propanol caused significant SC and keratinocyte perturbation in vitro together with damage to skin condition and function in vivo whereas ethanol did not. As a result, we show that ethanol-based sanitizers are better tolerated by skin, particularly in high-use settings, than other alcohols and should be the active ingredient of choice.

An in vitro peptide folding model suggests the presence of the molten globule state during nascent peptide folding

Although molten globules have been widely accepted as a general intermediate in protein folding, there is no clear evidence to show their presence during nascent peptide folding. This paper concentrates on whether the molten globule state occurs, and if it does, when does it form during nascent peptide folding, by comparing the changes in conformation during peptide chain extension of staphylococcal nuclease R. The results show that a large N-terminal fragment of staphylococcal nuclease, SNR121, which already contains more than 80% amino acid sequence of the nuclease, is found to fulfill all the criteria for the molten globule state, suggesting that the molten globule should occur at a later stage of peptide elongation. At this stage the hydrophobic collapse of the polypeptide chain occurs driven by the hydrophobic force, which leads to the formation of a solvent-accessible non-polar core, characterized by the high ANS-binding fluorescence. The nascent peptide folding of the nuclease is a hierarchical process that at the very least includes the following steps: secondary structure accumulation, pre-molten globule state, molten globule state, post-molten globule state and finally the native state. Constant conformation adjustment is necessary for correct folding and active expression of the protein.

MR Imaging Grading System for Skull Base Chordoma

BACKGROUND AND PURPOSE

Skull base chordoma has been widely studied in recent years, however, imaging characteristics of this tumor have not been well elaborated. The purpose of this study was to establish an MR imaging grading system for skull base chordoma.

MATERIALS AND METHODS

In this study, 156 patients with skull base chordomas were retrospectively assessed. Tumor-to-pons signal intensity ratios were calculated from pretreatment MR images R_T1 (ratio of tumor to pons signal intensity in T1 FLAIR sequence), R_T2 (ratio of tumor to pons signal intensity in T2 sequence) and R_EN (ratio of tumor to pons signal intensity in enhanced T1 FLAIR sequence), and significant ratios for overall survival and progression-free survival were selected to establish a grading system. Clinical variables among different MR imaging grades were then analyzed to evaluate the usefulness of the grading system.

RESULTS

R_T2 (P < .001) and R_EN (P = .04) were identified as significant variables affecting progression-free survival. After analysis, the classification criteria were set as follows: MR grade I, R_T2 > 2.49 and R_EN ≤ 0.77; MR grade II, R_T2 > 2.49 and R_EN > 0.77, or R_T2 ≤ 2.49 and R_EN ≤ 0.77; and MR grade III, R_T2 ≤ 2.49 and R_EN > 0.77. MR grade III tumors had a more abundant tumor blood supply than MR grade I tumors (P < .001), and the intraoperative blood loss of MR grade III tumors was higher than that of MR grade I tumors (P = .002). Additionally, skull base chordoma progression risk increased by 2.071 times for every single MR grade increase (P < .001).

CONCLUSIONS

A higher R_T2 value was a negative indicator of tumor progression, whereas a higher R_EN value was a positive risk factor of tumor progression. MR grade III tumors showed a more abundant blood supply than MR grade I tumors, and the risk of skull base chordoma progression increased with every single MR grade increase.

Immunogenicity of the recombinant serine rich Entamoeba histolytica protein (SREHP) amebiasis vaccine in the African green monkey

We report the first study in non-human primates of the safety and immunogenicity of a recombinant vaccine designed to prevent amebic liver abscess. In a pilot study, a recombinant vaccine containing the serine rich Entamoeba histolytica protein (SREHP) attached to a maltose binding protein (SREHP/MBP), which has been shown to be effective in preventing amebic liver abscess in rodent models of infection, was used to immunize two African Green Monkeys. Vaccination with SREHP/MBP resulted in no systemic side-effects. The monkeys receiving the SREHP/MBP protein developed antibodies that recognized the recombinant SREHP/MBP molecule, the native SREHP protein, and the surface of amebic trophozoites. Antiserum from SREHP/MBP-vaccinated monkeys could block the adhesion of E. histolytica trophozoites to mammalian cells, a feature that may correlate with vaccine efficacy. Attempts to produce amebic liver abscess in naive African Green Monkeys by direct hepatic inoculation with virulent E. histolytica trophozoites was not successful, suggesting this species is probably not suitable for vaccine efficacy studies.

The isolation and characterization of purified heterocomplexes of recombinant retinoic acid receptor and retinoid X receptor ligand binding domains

Retinoic acid exerts many of its biological effects by interaction with heterocomplexes of nuclear retinoic acid receptors (RARs) and retinoid X receptors (RXRs). To further examine this interaction, a glutathione S-transferase (GST) fusion protein containing the ligand binding domain of human RXR alpha has been used to copurify the ligand binding domain of human RAR gamma by affinity chromatography over glutathione-agarose. Complexes of recombinant RAR-RXR ligand binding domains retaining full ligand binding capacity were purified, and their interactions with various retinoids were characterized by fluorometric titration and photoaffinity labeling. Analyses of the distribution of limiting amounts of [3H]-all-trans-retinoic acid between cytoplasmic retinoic acid binding proteins, CRABP-I and CRABP-II, and the purified heterocomplexes indicate that all-trans-retinoic acid binds with comparable affinity to CRABP-I and the heterocomplexes, but with approximately 10-fold less affinity to CRABP-II. The aromatic retinoid acitretin, which is used in the treatment of psoriasis, binds relatively poorly to the purified heterocomplexes, although it binds with high affinity to the CRABPs. Acitretin displaces [3H]-all-trans-retinoic acid from the CRABPs and increases retinoic acid occupancy of the heterocomplexes. These results suggest that certain retinoids could potentially perturb the distribution of endogenous retinoic acid between the CRABPs and the nuclear receptors and thus affect retinoid signaling. The purified recombinant complexes should provide a useful model system for further structural analysis of the dimerization interface between the RAR and RXR ligand binding domains.

Identification and expression patterns of Halloween genes encoding cytochrome P450s involved in ecdysteroid biosynthesis in the cotton bollworm Helicoverpa armigera

20-Hydroxyecdysone (20E) is a key hormone which regulates growth, development and reproduction in insects. Although cytochrome P450 enzymes (P450s) participating in the ecdysteroid biosynthesis of 20E have been characterized in a few model insects, no work has been published on the molecular entity of their orthologs in the cotton bollworm Helicoverpa armigera, a major pest insect in agriculture worldwide. In this study, four cytochrome P450 homologs, namely HarmCYP302A1, HarmCYP306A1, HarmCYP314A1 and HarmCYP315A1 from H. armigera, were identified and evolutional conservation of these Halloween genes were revealed among lepidopteran. Expression analyses showed that HarmCYP302A1 and HarmCYP315A1 were predominantly expressed in larval prothoracic glands, whereas this predominance was not always observed for HarmCYP306A1 and CYP314A1. The expression patterns of Halloween genes indicate that the fat bodies may play an important role in the conversion of ecdysone into 20E in larval-larval molt and in larval-pupal metamorphosis, and raise the possibility that HarmCYP315A1 plays a role in tissue-specific regulation in the steroid biosynthesis in H. armigera. These findings represent the first identification and expression characterization of four steriodogenic P450 genes and provide the groundwork for future functional and evolutionary study of steroid biosynthesis in this agriculturally important pest.

Folding of SNase R begins early during synthesis: the conformational feature of two short N-terminal fragments of staphylococcal nuclease R

To further understand the folding of nascent peptide during the early course of peptide synthesis, two short N-terminal fragments of staphylococcal nuclease R (SNase R), SNR52 and SNR79, were made by deleting 97 and 70 amino acid residues from the C-terminus. The conformations of SNR52 and SNR79 were studied by FTIR and far-ultraviolet CD. The results demonstrate that even the short N-terminal fragments of SNase R still have a certain amount of residual ordered secondary structure in the physiological condition. The ordered secondary structures were mainly assigned as beta-strands and turns, which corresponds well to the structures of the N-terminal part in the native protein. The conformational changes during unfolding and refolding in different concentrations of guanidine hydrochloride (GuHCl), monitored by far-ultraviolet CD and intrinsic fluorescence, show that the interaction between amino acid residues, which governs the formation of their conformation are not random. Considered together with earlier studies (Jing et al., Biochim Biophys Acta 1995;1250:189-196; Zhou et al., J Biochem 1996:120: 881-888), the results suggest that the folding of nascent peptide chains begins early in the synthesis process and that the amount of ordered structure increases with increasing peptide chain length until the conformation of the biologically active protein is generated.

WTH3 is a direct target of the p53 protein

Previous results showed that overexpression of the WTH3 gene in multidrug resistance (MDR) cells reduced MDR1 gene expression and converted their resistance to sensitivity to various anticancer drugs. The WTH3 gene promoter was found to be differentially regulated in paired MDR vs non-MDR MCF7 cells owing to epigenetic modifications and transcription factor modulations. To understand further the mechanisms that govern WTH3's differential expression, we uncovered a p53-binding site in its promoter, which indicated that WTH3 could be regulated by the p53 gene. This hypothesis was then tested by different strategies. The resulting data revealed that (1) the WTH3 promoter was upregulated by the p53 transgene in diverse host cells; (2) there was a correlation between WTH3 expression levels and p53 gene status in a cell line panel; (3) a WTH3 promoter region was directly targeted by the p53 protein in vitro and in vivo. In addition, overexpression of the WTH3 gene promoted the apoptotic phenotype in host cells. On the basis of these findings, we believe that the negative role played by the WTH3 gene in MDR development is through its proapoptotic potential that is regulated by multiple mechanisms at the transcription level, and one of these mechanisms is linked to the p53 gene.

Prokaryotic functional expression and activity comparison of three CYP9A genes from the polyphagous pest Helicoverpa armigera

Cytochrome P450s (CYPs or P450s) have been long recognized as very important enzymes in the metabolism of xenobiotic and endogenous compounds, but only a few CYPs have been functionally characterized in insects. The effort in functional characterization of insect P450s is heavily hindered by technical difficulties in preparing active, individual P450 enzymes directly from the target insect. In this paper, we describe the functional expression of two additional pyrethroid resistance-associated CYP9A genes (CYP9A12 and CYP9A17) from the polyphagous pest Helicoverpa armigera in the facile Escherichia coli. The functionality of E. coli produced CYP9A12, CYP9A14, and CYP9A17 was investigated and activities of these CYP9As were compared against three probe substrates after reconstitution with NADPH-dependent cytochrome P450 reductase. The results showed that active forms of CYP9A12 and CYP9A17 were expressed in E. coli with a content of about 1.0-1.5 nmol mg-1 protein in membrane preparations. In vitro assays showed that CYP9A14 was capable of catalyzing O-dealkylation of methoxyresorufin (MROD), ethoxyresorufin (EROD), and benzyloxyresorufin (BROD), while CYP9A12 and CYP9A17 exhibited only MROD and EROD activities. Kinetic studies demonstrated that CYP9A14 had the greatest k cat/K m value for MROD, and CYP9A17 for EROD, while the lowest k cat/K m values for both MROD and EROD were observed for CYP9A12. The distinct biochemical traits suggest that the three paralogous CYP9As may play different roles in xenobiotic metabolism in this important pest.

The change of carnitine content in seminal plasma after reversible injection occlusion of vas deferens

The change in carnitine content in seminal plasma after reversible injection occlusion of vas deferens (RIOVD) was observed. RIOVD is a safe, effective and simple method of male fertility control. Carnitine was determined by microenzymatic method. The incidence of sperm disappearance increased with the duration of RIOVD and reached 90% at the end of 12 months after operation. Before RIOVD, the mean value of carnitine in seminal plasma was 336.9 +/- 78.1 nmol/ml (X +/- SD, n = 58); after RIOVD, the mean value of seminal plasma carnitine was 112.7 +/- 50.7 nmol/ml (n = 172) in the group with sperm disappearance, and 172.5 +/- 71.7 nmol/ml (n = 51) in the group without sperm disappearance. There was a significant difference in carnitine content between pre-operation and postoperation (p < 0.01). After RIOVD, the carnitine concentration in seminal plasma of the group with sperm disappearance was lower than that of the group without sperm disappearance (p < 0.01). The results suggest that carnitine content in seminal plasma following RIOVD may be a reference index for judging the success or failure of the operation.

Expression and clinical significance of ARTN and MMP-9 in endometrial carcinoma

The aim of this study was to detect the differential expression of Artemin (ARTN) and matrix metallopeptidase protein 9 (MMP-9) in endometrial carcinoma (EC) and to assess their clinical significance in order to provide insight into the pathological mechanism of tumor infiltration and metastasis in EC. A total of 48 patients who had undergone surgery for EC at the School of Medicine and Affiliated Hospital of HeBei University of Engineering between July 2015 and July 2016 were included in the study. The 48 patients were classified into 3 groups according to tumor stage: 27 patients with EC stage I, 12 patients with EC stage II and 9 patients with EC stage III. The samples collected from each patient included fresh normal endometrial tissue, endometrial simple hyperplastic tissue and endometrial atypical hyperplastic tissue. The transcription levels of ARTN and MMP-9 mRNA in each group were investigated using RT-PCR. The expression levels of ARTN and MMP-9 protein in each group were examined using Western blotting. Spearman’s correlation analysis was used to analyze the correlation between the expression levels of ARTN and MMP-9 proteins and EC tissue type. RT-PCR and Western blotting assays revealed that the expression levels of ARTN and MMP-9 were increased in normal endometrial tissue, simple hyperplastic tissue, atypical hyperplastic tissue and EC of stages I, II and III. The differences noted were statistically significant (P less than 0.05). Furthermore, Western blot analysis indicated that the expression levels of ARTN and MMP-9 proteins in lymphatic metastatic tissues were higher than those in non-lymphatic metastatic tissues (P less than 0.05). The expression levels in the infiltration tissues of the deep muscular layer were higher than those noted in the light muscular layer (P less than 0.05). The expression levels of ARTN and MMP-9 proteins were positively correlated (P less than 0.05). The data suggest that ARTN and MMP-9 are involved in the occurrence, development, invasion and metastasis of EC, and play a synergistic role in the development of EC and lymphatic metastasis.

Kinetics of plasma cytokines and its clinical significance in patients with severe trauma

OBJECTIVE

To examine the kinetics of plasma tumor necrosis factor alpha (TNF alpha), interleukin-6 (IL-6) and interleukin-8 (IL-8) in patients with severe trauma and to discuss their relationship with organ damage and endotoxemia.

METHODS

Seventeen patients (10 men and 7 women) with severe trauma were selected in this study. Their mean age was 37.9 +/- 11.9 years. All patients were divided into two groups according to injury severity score (ISS): group I with ISS from 16-25 (18.8 +/- 2.9, n = 10) and group II with ISS more than 25 (34.3 +/- 8.3, n = 7). Ten young healthy volunteers (6 men and 4 women) were used as controls. Plasma TNF alpha and IL-8 levels were assayed with enzyme-linked immunosorbent assay. IL-6 activity in the plasma was determined by bioassay with IL-6-dependent cell-line 7TD1. Limulus amebocyte lysate chromogenic test was used for plasma endotoxin assay.

RESULTS

Plasma cytokine levels in patients with trauma had a successively significant increase. Plasma TNF level increased earlier. Increases in plasma IL-6 and IL-8 occurred later. All the increases were significantly correlated with the severity of trauma and organ damage after trauma. In addition, obvious endotoxemia occurred at the early stage of trauma and was significantly correlated with the severity of trauma and the levels of plasma TNF alpha, IL-6 and IL-8.

CONCLUSIONS

Release of TNF alpha, IL-6 and IL-8 can be significantly increased in patients with severe trauma. The increase may be related to massive endotoxin translocation and may play an important role in the development of organ damage after trauma.