Novel mutations of PRSS1 gene in patients with pancreatic cancer among Han population / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>A high mortality rate of pancreatic cancer becomes a bottleneck for further treatment with long-term efficacy. It is urgent to find a new mean to predict the early onset of pancreatic cancer accurately. The authors hypothesized that genetic variants of cationic trypsinogen (PRSS1) gene could affect trypsin expression/function and result in abnormal activation of protease activated receptor-2 (PAR-2), then lead to pancreatic cancer. The aim of this study was to elaborate some novel mutations of PRSS1 gene in the patients with pancreatic cancer.</p><p><b>METHODS</b>Totally 156 patients with pancreatic cancer and 220 unrelated individuals as controls were enrolled in this study. The mutations of PRSS1 gene were analyzed by direct sequencing. K-ras Mutation Detection Kit was used to find the general k-ras gene disorder in the pancreatic cancer tissue. Then the clinical data were collected and analyzed simultaneously.</p><p><b>RESULTS</b>There were two patients who carried novel mutations which was IVS 3 + 157 G > C of PRSS1 gene in peripheral blood specimens and pancreatic cancer tissue. What's more, it was surprising to find a novel complicated mutation of exon 3 in PRSS1 gene (c.409 A > G and c.416 C > T) in another young patient. The complicated mutation made No. 135 and No. 137 amino acid transfer from Thr to Ala and Thr to Met respectively. No any mutation was found in the normal controls while no mutations of k-ras gene were detected in the three patients.</p><p><b>CONCLUSION</b>Mutations of PRSS1 gene may be an important factor of pancreatic cancer.</p>

Construction of the eukaryotic coexpression vector containing Mycobacterium tuberculosis heat shock protein 70 and green fluorescent protein / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct an eukaryotic coexpression vector containing Mycobacterium tuberculosis heat shock protein 70 (mtHSP70) and enhanced green fluorescent protein (EGFP) controlled by cytomegalovirus promoter using pIRES-EGFP vector.</p><p><b>METHODS</b>The mtHSP70 gene fragment was amplified by PCR from pVAX-mtHSP70-HSV2gD using specific primers. The PCR product was cloned into the vector pMD 18-T vector, and the correct clone was selected according to DNA sequence analysis. The interested mtHSP70 gene fragment was subcloned into pCMV-IRES-EGFP vector with XhoI and EcoR I digestion. The recombinant plasmid was transfected into mouse melanoma B16 cell line, and the green fluorescent cells were detected by fluorescence microscopy and mtHSP70 expression was detected by Western blotting.</p><p><b>RESULTS</b>The recombinant plasmid obtained was confirmed by enzyme digestion. The transfected mouse melanoma B16 cells exhibited green fluorescence under fluorescence microscopy and expressed mtHSP70 protein as demonstrated by Western blotting.</p><p><b>CONCLUSION</b>The eukaryotic coexpression vector PCMV-mtHSP70-IRES-EGFP has been established to allow further investigation of the role of mtHSP70 gene in tumor immunotherapy.</p>

Novel mutation and polymorphism of PRSS1 gene in the Chinese patients with hereditary pancreatitis and chronic pancreatitis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Mutations in the cationic trypsinogen gene (PRSS1) have been detected in patients with hereditary pancreatitis (HP). This study investigated the prevalence of the R122H (c.365 G > A), A121T (c.361 G > A) and D162D (c.488 C > T) mutations or polymorphisms in the common, non-hereditary forms of chronic pancreatitis and in an HP family.</p><p><b>METHODS</b>DNA was prepared from blood samples of 54 patients with chronic pancreatitis (35 alcoholic, 17 idiopathic and 2 hereditary) and 120 normal controls. The PRSS1 genes were amplified by polymerase chain reaction (PCR) and their products were analyzed by sequencing and related clinical data were also collected.</p><p><b>RESULTS</b>A new polymorphism (c.488 C > T) of PRSS1 was found in 25 patients with chronic pancreatitis (including one affected member of the HP family) and six members of the normal controls. The C/T genotype was significantly increased in chronic pancreatitis (OR: 16.379, 95% CI: 5.7522 - 52.3663), the frequency of c.488 C > T change was in according with the Hardy-Weinberg equilibrium, but it doesn't affect the clinical phenotype. The commonly reported change of R122H (c.365 G > A) was not detected in any of the study subjects. c.361 G > A was found in 2 affected members and one unaffected carrier in an HP family. One of the affected members of an HP family had c.361 G > A mutation and polymorphism (c.488 C > T) in the PRSS1 gene at the same time. The patient's clinical values (C3, C4, CA19-9 and HbA1c) were higher than those of the other patients with chronic pancreatitis. The two patients with HP developed diabetes mellitus and their father died with pancreatic cancer.</p><p><b>CONCLUSION</b>A new polymorphism (c.488 C > T) in the PRSS1 gene is associated with chronic pancreatitis, but it did not affect the clinical phenotype while the A121T (c.361 G > A) mutation in the gene shows a significant correlation in the patients with HP.</p>

Loss of heterozygosity in the region of chromosome 4p15.1-4q12 in nasopharyngeal carcinoma patients with familial history / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the allelic loss of heterozygosity (LOH) in the region of chromosome 4p15.1-4q12 in nasopharyngeal carcinoma (NPC) patients with family history.</p><p><b>METHODS</b>Tumor cells and lymphocytes were obtained from paraffin-embedded biopsied tissue section by microdissection. LOH detections were carried out on 25 NPC patients with family history by PCR-based microsatellite polymorphism analysis using 7 pairs of microsatellite markers primers. The microsatellite loci located in 4p15.1-4q12 region. Genescan software was used to analyse LOH at each locus.</p><p><b>RESULTS</b>Ninety-two percent of NPC cases (23/25) with family history was showed at least one microsatellite marker of LOH. Higher frequencies of LOH were found at three loci: D4S238 (56%), D4S350 (50%), D4S1547 (50%). The minimal common region of deletion might be defined between D4S350 and D4S1547.</p><p><b>CONCLUSION</b>The higher incidence of LOH at D4S350 and D4S1547 suggests that there may be a potential tumor suppressor gene located in the two regions.</p>

NP9 gene inhibits tumorigenicity of nasopharyngeal carcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the effect of NP9 on the growth of transplanted nasopharyngeal carcinoma (NPC) in nude mice and explore the mechanisms involved.</p><p><b>METHODS</b>Recombinant pRc/CMV2-NP9 plasmid was constructed and transfected into the NPC cell lines by lipofectamine 2000. Cell clones stably expressing NP9 were obtained by detecting the mRNA expression of NP9 in G418-resistant clones with RT-PCR. The tumorigenicity and size of transplanted tumors were assessed after inoculation of NPC cells and their transgene clones into Balb/C mice. The expression of PCNA and cyclin D1 in transplanted tumors was detected by immunohistochemistry.</p><p><b>RESULTS</b>The expression of NP9 was detected in some of NP9 gene-transfected G418-resistant clones of CNE1 and SUNE1. In vivo experiments showed that the tumorigenicity of CNE19 clone was decreased significantly compared to that of CNE1 and its vector control, and the transplanted tumors grew more slowly from SUNE1/NP9 than from SUNE1 and SUNE1/vector. Compared with the vector control, the expression of cyclin D1 and PCNA in CNE1/NP9 transplants was decreased.</p><p><b>CONCLUSION</b>NP9 inhibits tumorigenicity and growth of NPC transplanted tumor by down-regulating the expression of cyclin D1 and PCNA.</p>

Construction of a trans-splicing ribozyme for restoring EGFP truncation mutation / 生物工程学报

Special designed group I intron ribozymes can specifically splice objective RNA, repair the mutant gene in RNA level. The specificity of ribozyme is determined by nucleotides specific internal guide sequence (IGS) introduced to the enzyme. In this study, fragment sequence containing Tetrahymena thermophilia intron I of 26S rRNA gene was cloned and cis-splicing activity of this ribozyme was confirmed by in vitro transcription. For evaluating the trans-splicing activity of this ribozyme, a truncated mutant Green Fluorescence Protein (GFP) vector, XYQ5/XYQ10- pEGFP-C2, was constructed. This vector deleted the 3' end 564bp fragment of EGFP coding sequence, led to the lost the activity of emitting green fluorescence. Trans-splicing ribozyme plasmids ptrans-rib-CMV2 for remedy of the truncated mutant EGFP was constructed by PCR and molecular cloning techniques. This vector utilizing cloned 26S rRNA intron 1 as core enzyme; selecting T-G site at 194bp of EGFP coding sequence as splicing receptor, designed an IGS which is inversely complement to the 188-193nt of EGFP mRNA; the 195-890bp fragment of EGFP coding sequence was ligated to the 3'-end of ribozyme core. The fragment containing these components was inserted to a eukayotic expression vector pRC-CMV2. Using linearized XYQ5/XYQ10- pEGFP-C2 and ptrans-rib-CMV2 as templates, truncated EGFP mRNA and the constructed ribozyme vector were transcribed and mixed to evaluate the trans-splicing activity. Analysis of in vitro transcription products mix by RT-PCR verified the existence of wild type EGFP mRNA molecule. Co-transfection of XYQ5/XYQ10- pEGFP-C2 with ptrans-rib-CMV2 to Hela cells proved this ribozyme restored green fluorescence within cell, but the efficiency was low.