Epidermal growth factor induces HCCR expression via PI3K/Akt/mTOR signaling in PANC-1 pancreatic cancer cells

BACKGROUND

Human cervical cancer oncoprotein 1 (HCCR-1), reported as a negative regulator of p53, is over-expressed in a variety of human cancers. However, it is yet unknown whether HCCR-1 plays any role in pancreatic cancer development. The aim of this study was to investigate the effect of epidermal growth factor on the expression of HCCR in pancreatic cancer cells, and to explore if PI3K/Akt/mTOR signaling pathway mediated this expression.

METHODS

A polyclonal antibody against HCCR protein was raised by immunizing Balb/c mice with the purified recombinant protein pMBPc-HCCR. Tissue samples were constructed on a tissue chip, and the expression of HCCR was investigated by immunohistochemistry assay and Western blotting. Pancreatic cell line, PANC-1 cells were stably transfected with plasmids containing sense-HCCR-1 fragment and HCCR siRNA fragment. MTT and transwell assay were used to investigate the proliferation and invasion of stable tansfectants. The specific inhibitor of PI3K and mTOR was used to see if PI3K/mTOR signal transduction was involved in the induction of HCCR gene expression. A Luciferase assay was used to see if Akt can enhance the HCCR promoter activity.

RESULTS

HCCR was up-regulated in pancreatic tumor tissues (mean Allred score 4.51+/-1.549 vs. 2.87+/-2.193, P<0.01), especially with high expression in poorly differentiated pancreatic cancer. The growth of cells decreased in HCCR-1 siRNA transfected cells compared with vector transfectants. The number of invasion cells was significantly lower in HCCR-1 siRNA transfected cells (24.4+/-9.9) than that in vector transfectants (49.1+/-15.4). Treatment of PANC-1 cells with epidermal growth factor increased HCCR protein level in a dose- and time-dependent manner. However, application of LY294002 and rapamycin caused a dramatic reduction of epidermal growth factor-induced HCCR expression. Over-expression of exogenous constitutively active Akt increased the HCCR promoter activity; in contrast, dominant negative Akt decreased the promoter activity.

CONCLUSIONS

EGF-induced HCCR-1 over-expression is mediated by PI3K/AKT/mTOR signaling which plays a pivotal role in pancreatic tumor progression, suggesting that HCCR-1 could be a potential target for cancer therapeutics.

Identification of an HLA-A*0201-restrictive CTL epitope from MUC4 for applicable vaccine therapy

Recent research has indicated that MUC4 plays an important role in the development of many tumors and may prove useful as a novel cancer immunotherapy target. We aimed to identify HLA-A*0201-restrictive cytotoxic T lymphocyte (CTL) epitopes of the cancer-associated antigen MUC4. The MUC4 sequence was scanned for immunogenic peptides using HLA-binding prediction software. Dendritic cells (DCs) from peripheral blood mononuclear cells (PBMCs) were induced by cytokines. Five possible CTL epitopes were selected by software analysis, synthesized, and used to pulse mature DCs. The CD8(+) T cells from PBMCs from an HLA-A*0201 healthy donor were stimulated with autologous MUC4-peptide-loaded DCs and expanded in vitro. T cell activation was assessed by ELISPOT, and cytotoxicity was determined by (51)chromium ((51)Cr)-release assays. Our results show that CTLs induced by peptide P01204 could lyse T2 cells pulsed with peptide P01204 and HCT-116 cells (MUC4(+), HLA-A2(+)). Compared with a control peptide, P01204 increased the number of IFN-gamma producing T cells. Overall, these results suggest that P01204 is a novel HLA-A*0201-restrictive CTL epitope of the cancer-associated antigen MUC4. This will provide a foundation for the development of tumor-specific peptide vaccines.

Surface hydrophilisation and antibacterial functionalisation for microporous polypropylene membranes

The surface properties of polymer membranes are crucial to their separation performances. For the microporous polypropylene membranes, the high hydrophobicity and lack of functionality easily cause protein adsorption and subsequent microorganism attachment and biofilm formation, i.e. biofouling. Thus, their applications in water treatment, bioseparation and biomedical fields are largely limited. Surface hydrophilisation and antibacterial functionalisation are, therefore, reasonably necessary. This review provides a concise summarisation of related studies according to the surface modification strategies. Especially, the interfacial crosslinking approach developed in our previous studies is presented in detail.

[Diagnosis and surgical treatment for non-functional islet cell tumor: a retrospective analysis of 44 cases]

OBJECTIVE

To evaluate the methods of diagnosis and surgical treatment for nonfunctional islet cell tumor (NICT).

METHODS

Forty-four patients with non-functional islet cell tumor treated at the First Affiliated Hospital of Nanjing Medical University during January 1968 to June 2008 were analyzed retrospectively. There were 9 males and 35 females, aged from 7- to 70-years-old. Clinical manifestation: 15 cases (34.1%) of abdominal masses, 17 patients (38.6%) with epigastric or back pain, 5 cases of jaundice, 5 cases (11.4%) for upper abdominal fullness or vomiting, 10 cases (22.7%) of pancreatic tumor noticed by routine health checkups or imaging examinations. Imaging examination: CT scan, sonography, ERCP, MRI, upper GI series were performed in 33 (75.0%), 16 (36.4%), 6 (13.6%), 2 (4.5%), and 10 cases (22.7%) respectively. Operation methods: 39 patients (88.6%) underwent surgical resection and the other 5 patients did not.

COMPLICATIONS

pancreatic fistula in 7 patients (15.9%), intra-abdominal bleeding in 4 (9.1%), gastrojejunal anastomosis outlet obstruction in 1 (2.3%), biliary fistula in 2 (4.5%) and incisional infection in 3 (6.8%). Surgery related mortality happened in 2 patients (4.5%), both treated before 1999. Twenty-five patients underwent operation between January 1999 and June 2008 were followed up for 6 to 108 months. All survive except one died 75 months after the surgery for unknown reason.

CONCLUSIONS

No specific clinical manifestation is recognized for non-functional islet cell tumor. Spiral CT is an optimal diagnostic method, while surgery is the first choice for treatment. Middle segmental pancreatectomy has become an alternative surgical protocol for NICT.

Protective role of angiotensin II type 2 receptor signaling in a mouse model of pancreatic fibrosis

The renin-angiotensin system contributes to pathological processes in a variety of organs. In the pancreas, blocking the angiotensin II (AII) type 1 receptor (AT1) attenuates pancreatic fibrogenesis in animal models of pancreatitis. Because the role of the AII type 2 receptor (AT2) in modulating pancreatic injury is unknown we investigated the role of AT2 in pancreatic injury and fibrosis. Pancreatic fibrosis was induced by repetitive cerulein administration in C57BL/6 wild-type (WT) or AT2-deficient (AT2-/-) mice and assessed by morphology and gene expression at 10 days. There was no difference between WT and AT2-/- mice in the degree of acute pancreatic injury as assessed by amylase release at 9 and 12 h and by histological examination of the pancreas at 12 h. In contrast, parenchymal atrophy and fibrosis were more pronounced in AT2-/- mice compared with WT mice at 10 days. Fibrosis was accompanied by activation of pancreatic stellate cells (PSC) evaluated by Western blot analysis for alpha-smooth muscle actin and by immunocytochemistry; PSC activation was further increased in AT2-/- mice compared with WT mice. The level of pancreatic transforming growth factor-beta1 mRNA and protein after repetitive cerulein treatment was higher in AT2-/- mice than in WT mice. Our results demonstrate that, in contrast to AT1 receptor signaling, AT2 receptor signaling modulates protective antifibrogenic effects in a mouse model of cerulein-induced pancreatic fibrogenesis. We propose that the effects of AII on injury-induced pancreatic fibrosis may be determined by the balance between AT1 and AT2 receptor signaling.

Effect of CYP2C19 genetic polymorphisms on the efficacy of proton pump inhibitor-based triple therapy for Helicobacter pylori eradication: a meta-analysis

OBJECTIVE

CYP2C19 polymorphisms have been inconsistently reported to associate with the efficacy of proton pump inhibitor (PPI)-based triple therapies for eradicating Helicobacter pylori infection. The aim of this meta-analysis was to determine whether CYP2C19 polymorphism affect H. pylori eradication rates obtained with first-line PPI-based triple therapies.

METHODS

A systematic literature search was conducted up to July 2007 using Medline, PubMed, EMBase, Cochrane Central Register of Controlled Trials (CENTRAL), ISI Web of Science, CNKI (Chinese), and Wanfang (Chinese) digital database. MeSH terms and keywords included proton pump inhibitor, omeprazole, lansoprazole, rabeprazole, pantoprazole, or esomeprazole, cytochrome P4502C19 or CYP2C19, and Helicobacter pylori or H. pylori. Twenty articles met the inclusion criteria, and were included in the meta-analysis by using Review Manager 4.2.8.

RESULTS

Eradication rates were significantly different between poor metabolizers (PM) and heterozygous extensive metabolizers (HetEM) (odds ratio (OR) = 1.73, p = .002) and between PM and homozygous extensive metabolizers (HomEM) (OR = 2.79, p < .0001). Moreover, eradication rates were also significant difference between HetEM and HomEM (OR = 2.00, p < .0001). Triple omeprazole and lansoprazole therapies achieved higher H. pylori eradication rates in PM than in HomEM (OR = 4.28, p = .0005 for omeprazole and OR = 3.06, p = .001 for lansoprazole), and higher in HetEM than those in HomEM (OR = 3.22, p < .0001 for omeprazole and OR = 1.95, p = .040 for lansoprazole). Rabeprazole therapies had no significant effect on H. pylori eradication rates (between PM and HomEM, OR = 1.35, p = .610 and between HetEM and HomEM, OR = 1.57, p = .190). No significant difference in H. pylori eradication rates between PM and HetEM was observed in the three individual PPI therapies.

CONCLUSION

The efficacy of omeprazole- and lansoprazole-based first-line triple therapies at the standard doses is dependent on CYP2C19 genotype status, which appears not to affect the efficacy of the regimens including rabeprazole.

Development of a cell-based assay for monitoring hepatitis C virus ns3/4a protease activity

Hepatitis C virus (HCV) NS3/4A (non-structural 3 and 4 B) protease plays a key role in the processing of polyprotein precursor and it becomes an attractive target for antiviral drug discovery. We developed a cell-based assay for monitoring of the NS3/4A protease activity in mammalian cells that is an important step in screening of specific drugs against the protease. The recombinant caspase 3 (rCasp3) was used as the specific substrate for NS3/4A protease. The endogenous cleavage sites in the procaspase 3 molecule were substituted by decapeptides specific for NS3/4A protease. The activation of rCasp3 depended on its specific cleavage by NS3/4A protease and resulted in an apoptosis of stable cells expressing the protease. The difference in cell viability between the cells expressing NS3/4A protease transfected with rCasp3 and the counterparts pretreated with NS3/4A protease inhibitors could be estimated by a spectrophotometry based on 3-(4,5-dimethylthioazol- 2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) staining of cells in microplates. Thus, we developed a simple and cost-effective colorimetric assay for evaluating NS3/4A protease activity enabling the screening of candidate NS3/4A protease inhibitors.

[Combined multiple organ resection in 16 patients with adenocarcinoma of the body or tail of the pancreas]

OBJECTIVE

To investigate the feasibility and therapeutic results of multiple organ resection in patients with tumor of the body and tail of pancreas.

METHODS

The clinical and pathological data were analysed in 16 consecutive patients with neoplasm of the body and tail of pancreas from 1999 to 2004 retrospectively.

RESULTS

Multiple organ resection was performed in 6 cases of primary pancreatic adenocarcinoma of the body and tail (3 cases of pancreatic cancer, 2 cases of malignant glucagonoma, and 1 case of well-differentiated pancreatic stromal sarcoma) and 10 cases of extrapancreatic malignancy (4 cases of gastric cancer, 2 cases of gastric leiomyosarcoma, 1 case of duodenal cancer, and 3 cases of colon cancer of hepatic flexure). Distal pancreatectomy with splenectomy was performed in all cases. In addition, 10 patients received splenic flexure colectomy, 6 patients received distal gastrectomy, 3 patients received left nephrectomy, left colectomy, total gastrectomy, liver lobe resection, left adrenalectomy, and local diaphragma resection, and 2 patients received transverse colectomy, subtotal colectomy, proximal proctectomy, proximal gastrectomy, and duodenectomy. No perioperative death and severe complications were observed. Patients with primary pancreatic cancer or pancreatic stromal sarcoma died within 1 year. Two patients with malignant glucagonoma died 51 and 39 months later. The 3-year survival rate was 70% in 10 patients with extrapancreatic malignancy, among which 2 patients with enteric cancer have survived 37 and 48 months.

CONCLUSION

Radical combined multiple organ resection may be performed actively in appropriately selected patients.

[Preliminary studies on tissue culture and agrobacterium-medicated transformation of Brassica campestris ssp. chinensis]

The hypocotyls and cotyledons of the asepetic seedling of Brassica campestris ssp. chinensis L cv. Pudongaijiecai) were used as explants for tissue culture. Adventitious buds were differentiated on modified MS medium supplemented with TDZ 1-2 mg/L, NAA 0.2-1 mg/L and AgNO3 7.5 mg/L. The percentage of explants which formed buds of cotyledons was about 56%, and that of hypocotyls was about 37%. When the regenerated explants were transferred onto MS medium with 2 i.p. 5 mg/L and NAA 0.1 mg/L for two weeks, whole plantlets were obtained by culturing the regenerated shoots on 1/2 MS medium with NAA 0.1 mg/L. Agrobacterium tumefaciens strain (LBA 4404/PBI 121) carrying the GUS gene and Npt II gene was used for transformation. After 2 days of coculture, the hypocotyls and cotyledons were transferred onto regenerated medium containing CP 300 mg/L for bud formation. After 4-5 weeks, the differentiated buds were transferred onto selection medium with CP 200 mg/L and Km 10 mg/L for 1 month, then the green shoots were transferred onto the rooting medium containing Cef 100 mg/L and Km 20 mg/L. 4-5 weeks later, plantlets with Km resistance were obtained and some of them showed higher enzymatic activities of beta-glucuronidase than control ones.

[Cleavage activity of ribozymes on a target RNA of tobacco mosaic virus in E. coli]

A target cDNA fragment from TMV RNA was inserted to a reporter gene CAT immediately to the 3' end of the translation initiation codon ATG resulting in the formation of a chimeric CAT gene in an in vivo transcription and expression vector. The in vivo activities of various ribozymes on the target sequence were observed by determining the changes of the CAT activities of the chimeric CAT gene expressed in E. coli. The CAT activity was reduced by up to 30% when a specific ribozyme RZ1, RZ1A or RZ1B was transcribed, no change in CAT activity was observed when a non-specific ribozyme RZ3 was expressed. The protein electrophoresis and primer extension experiments indicated that this reduction in CAT activity was due to the specific cleavage of the ribozymes to the chimeric CAT mRNA at the target region hence the decrease in CAT protein synthesis.

[Cloning and expression of an antifreeze peptide gene of winter flounder in E. coli]

Antifreeze peptide (AFP) produced in some animals is able to lower freezing temperature to prevent serum from freezing. There is a great potential to apply AFP in various circumstances wherever tolerance to cold environment is required. cDNA copies of AFP and proAFP coding sequence were synthesized according to the published sequence from a winter flounder (Pseudopleuronectes americanus). Expression of AFP or proAFP cDNA was initially tested in E. coli using a procaryotic expression vector. Level of the expression was essentially low indicated by SDS-PAGE and protein staining procedures. In order to detect the low level expression, the AFP (or proAFP) cDNA was fused, in frame, to the 5'-end of the CAT reporter gene resulting in a chimeric AFP/CAT (or proAFP/CAT) cDNA. The product translated from such a chimeric mRNA must contain a N'-terminal AFP (or proAFP) portion and C'-terminal CAT portion. Thus, low level of expression of AFP (or proAFP) in the fused form may be detected indirectly by sensitive CAT assay as long as the chimeric CAT still remains the activity. As expected, CAT activity has been clearly detected in protein extract from induced E. coli indicating that AFP (or proAFP) cDNA clones be expressed in E. coli.

Structure-specific binding of wound tumor virus transcripts by a host factor: involvement of both terminal nucleotide domains

A gel retardation assay was used to demonstrate binding of wound tumor virus transcripts by a protein component of leafhopper vector cell extracts. Comparative binding studies employing terminally modified and internally deleted transcripts established that the segment-specific inverted repeats present in the terminal domains of the viral transcripts were necessary but not sufficient for optimal binding. An additional involvement of internal sequences in either the formation or the stabilization of the binding complex was indicated. Results of competitive binding experiments confirmed the sequence- and structure-specificity of the protein-RNA interaction and revealed apparent differences in the ability of individual viral transcripts to form a stable binding complex. Possible implications of structure-specific interactions between wound tumor virus transcripts and a host component and the role of the terminal inverted repeats are discussed.

Effect of treatment with nimodipine in patients with mild and moderate essential hypertension

This study shows that nimodipine significantly reduces levels of blood pressure in patients with mild and moderate essential hypertension. Hypotensive efficacy is less than with nifedipine, but side effects are light, and the drug is shown to reduce serum Na+ and cholesterol and there is regression of LVH (ECG).

Complete nucleotide sequence of wound tumor virus genomic segments encoding nonstructural polypeptides

Sequence analysis of the genomic segments which encode the five wound tumor virus nonstructural polypeptides has been completed. The complete nucleotide sequence of segments S4 (2565 bp), S6 (1700 bp), S9 (1182 bp), and S10 (1172 bp) are presented in this report while the sequence of segment S12 (851 bp) has been described previously (T. Asamizu, D. Summers, M. B. Motika, J. V. Anzola, and D. L. Nuss, 1985, Virology 144, 398-409). Comparison of the only published sequence for another member of the genus Phytoreovirus, that of rice dwarf virus segment S10, with the combined available wound tumor virus sequence data revealed similarity with WTV segment S10: 54.9 and 30.6% at the nucleotide and amino acid level, respectively. Although wound tumor virus and rice dwarf virus differ in plant host range, tissue specificity, vector range, and disease symptom expression, the level of sequence similarity shared by the two segments suggests a common origin for these viruses. The potential use of a phytoreovirus sequence database for predicting functions of viral encoded gene products is considered.

The 3'-terminal sequence of a wound tumor virus transcript can influence conformational and functional properties associated with the 5'-terminus

We recently reported the presence of segment-specific inverted repeats within the terminal regions of wound tumor virus genomic segments (J. V. Anzol, Z. Xu, T. Asamizu, and D. L. Nuss, 1987, Proc. Natl. Acad. Sci. USA, 84, 8301-8305). This report describes a series of experiments designed to investigate potential intramolecular interactions involving the 5'- and 3'-terminal domains of wound tumor virus transcripts. A series of transcription vectors were constructed which allowed the synthesis of an exact copy of the transcript corresponding to genomic segment S8 and four analogs that differed from the authentic sequence only at the immediate 3'-terminus. Modifications designed to extend or alter the 3'-terminal inverted repeat altered the in vitro translational efficiency of the transcript and the sensitivity of phosphodiester bonds within the immediate 5'-terminal domain to digestion by nuclease T1. These results were consistent with computer-assisted secondary structure analyses of the complete nucleotide sequence of transcripts corresponding to six genomic segments which predicted intramolecular interactions involving the terminal inverted repeats. Potential roles of the terminal domains in expression, sorting and packaging of a segmented RNA genome are considered.

Assignment of wound tumor virus nonstructural polypeptides to cognate dsRNA genome segments by in vitro expression of tailored full-length cDNA clones

Presumptive full-length cDNA clones of 9 of the 12 wound tumor virus double-stranded RNA genome segments were tailored for efficient in vitro expression by a recently described strategy [Z. Xu, J.V. Anzola, and D.L. Nuss (1987) DNA6, 505-513]. In vitro synthesized polypeptides specified by synthetic transcripts corresponding to the tailored cDNAs comigrated in polyacrylamide gels with in vivo synthesized viral-specific polypeptides. This analysis confirmed the functional integrity of the tailored cDNA clones and identified cognate genome segments which encode all five viral non-structural polypeptides as well as four structural polypeptides; two which comprise the capsid, one located in the viral core and one associated with the outer protein coat.

Segment-specific inverted repeats found adjacent to conserved terminal sequences in wound tumor virus genome and defective interfering RNAs

Defective interfering (DI) RNAs are often associated with transmission-defective isolates of wound tumor virus (WTV), a plant virus member of the Reoviridae. We report here the cloning and characterization of WTV genome segment S5 [2613 base pairs (bp)] and three related DI RNAs (587-776 bp). Each DI RNA was generated by a simple internal deletion event that resulted in no sequence rearrangement at the deletion boundaries. Remarkably, although several DI RNAs have been in continuous passage for more than 20 years, their nucleotide sequences are identical to that of corresponding portions of segment S5 present in infrequently passaged, standard, transmission-competent virus. The positions of the deletion breakpoints indicate that the minimal sequence information required for replication and packaging of segment S5 resides within 319 bp from the 5' end of the (+)-strand and 205 bp from the 3' end of the (+)-strand. The terminal portions of segment S5 were found to contain a 9-bp inverted repeat immediately adjacent to the conserved terminal 5'-hexanucleotide and 3'-tetranucleotide sequences shared by all 12 WTV genome segments. The presence of a 6- to 9-nucleotide segment-specific inverted repeat immediately adjacent to the conserved terminal sequences was found to be a feature common to all WTV genome segments. These results reveal several basic principles that govern the replication and packaging of a segmented double-stranded RNA genome.

Tailored removal of flanking homopolymer sequences from cDNA clones

Terminal homopolymer sequences introduced during the synthesis and cloning of cDNA molecules often interfere with subsequent expression of the cloned cDNA. We describe a general method for the removal of homopolymer flanking sequences from cDNA inserts and subsequent tailoring of the resulting termini. The cDNA insert containing homopolymer tails is first subcloned into the multiple cloning site of an appropriate transcription vector. cDNA copies are then generated from in vitro-synthesized transcripts using oligonucleotide primers complementary to the nucleotide sequences adjacent to the homopolymer tails. The resulting double-stranded cDNA contains the homopolymer flanking sequences as 3'-terminal extensions that are conveniently removed by the 3'----5' exonuclease activity of T4 DNA polymerase. If the oligonucleotide primers also contain 5'-terminal noncomplementary sequences that specify potential restriction endonuclease sites, those sites are subsequently generated by the 5'----3' polymerase activity of the T4 DNA polymerase. Thus, in the same reaction, flanking homopolymer sequences are removed and the resulting termini are tailored to specify desired sequences.

The antigenic analysis of haemorrhagic fever with renal syndrome viruses in China by monoclonal antibodies

Thirty-six strains of haemorrhagic fever with renal syndrome (HFRS) virus were isolated from patients and a number of host animals in various areas in China. They were analysed by an immunofluorescence test (IFAT) using 10 monoclonal antibodies (McAbs) specific for the HFRS virus; antigenic differences among the strains have been demonstrated. The HFRS virus strains revealed nine different reactions with the McAbs, showing that there are at least nine different antigenic determinants including group-, type- and strain-specific. Analysis of the results shows that antigenic differences among the HFRS virus strains are mainly related to differences in the host animals.