AIM: To investigate the genetic and epigenetic alterations of p14~ ARF gene and mutation status of p53 gene in human primary colorectal carcinomas and to analyze the relationship between the two gene changes and the role of abrogation of the p14~ ARF -p53 pathway in colorectal carcinogenesis. METHODS: The homozygous deletions, mutations, methylation of 5′ CpG islands, mRNA expression of p14~ ARF gene and mutations of p53 gene were assessed by PCR, direct sequencing, methylation-specific PCR, and RT-PCR in the tumorous and matched adjacent normal colorectal tissues from 56 patients with colorectal carcinoma. RESULTS: ① p14~ ARF alterations were detected in 27% (15/56) of colorectal carcinoma tissues studied, of which 1 case showed homozygous deletion, 14 cases showed 5′ CpG island methylation, and no mutation was found in any tumor. ②15 colorectal carcinomas with p14~ ARF alterations indicated lack of (13 cases) or at low level of expression (2 cases) of p14~ ARF mRNA, while expression of the p14~ ARF transcript was detected in the remaining 41 colorectal carcinomas and any matched adjacent normal colorectal tissues. ③ The mutations of p53 gene were detected in 48% (27/56) of colorectal carcinomas investigated. ④ Of these 56 cases, 12 had p14~ ARF alterations alone, 24 had p53 mutations alone, 3 had both p53 mutations and p14~ ARF methylation, and 17 had neither. 70% (39/56) of the samples had either or both abnormalities of the two genes, and p14~ ARF hypermethylation was related to wildtype p53 (P

AIM: To construct the shuttle plasmid vector for thymidine kinase (tk) and EGFP fusion protein gene driven by IGF - Ⅱ P3 promoter, and investigate the specific killing effect of the HSV - tk/GCV system on hepatocellular carcinoma(HCC) cells in vitro. METHODS: Recombinant shuttle plasmid vector was constructed by techniques of genetic recombination and screening, and identified by restriction digestion and sequencing analysis. Then the recombinant shuttle plasmid was transfected into HepG2 and HeLa cells by techniques of lipofectamine transfection and its expression was detected by fluorescence microscope and RT -PCR. Cell killing after ganciclovir(GCV) application was determined by MTT. RESULTS: Identification of pDC316 -tkEGFP- P3 by enzyme digestion and sequencing analysis showed that the length, inserted location and direction of the target genes which were inserted into the recombinant were correct. It was found that enhanced green fluorescence protein could only be seen in HepG2 cells, but not in HeLa cells. The results of RT -PCR showed that only two bands could be seen in the samples of pDC316 -tkEGFP- P3 transfected HepG2 cells. The MTT test showed the selective cytotoxicity of GCV to the transfected HepG2 cells. CONCLUSION: The shuttle plasmid vector carrying the tkEGFP fusion protein gene driven by IGF - Ⅱ P3 promoter has been constructed successfully and its specific expression in HepG2 cells provided a sound basis for targeted gene therapy for HCC.

Objective In order to examine the value of the combination of carotid artery ultrasound and Transcrani-al Doppler (TCD) in the evaluation of carotid artery stenosis stenting. Methods Seventy-one carotid stenosis cases con-firmed by digital subtraction angiography (DSA) who had cerebral ischemia symptoms and received stent implantation were reviewed. Carotid artery ultrasound and TCD were adopted to measure the vessel diameter, peak systolic velocity (PSV) of the narrow segment, PSV and pulsatility index (PI) of ipsilateral middle cerebral artery (MCA) before and after the treatment of intravascular stents, and a comparison analysis was made. Results Carotid stent implantation significant-ly improved the inner diameter, PSV of the narrow part, PSV and PI of the MCA on the stenotic side. Inner diameter of the narrow part was 3.13±0.83, 4.77±0.51 and 4.64±0.52 mm at before, one week and one year after the implantation, re-spectively (P<0.05). The PSV of the narrow part was 190.69±113.65, 86.15±30.52 and 90.28±29.79 cm/s at before, one week and one year after the implantation, respectively(P<0.05).PSV of the MCA on the stenotic side was 77.68±14.66, 115.62±22.32 and 108.89±20.29 cm/s at before, one week and one year after the implantation, respectively(P<0.05). PI of the MCA on the stenotic side was 0.81±0.01, 1.07±0.01 and 1.06±0.02 at before, one week and one year after the implantation, respectively (P<0.05). Conclusions The present study demonstrates that the combination of carotid artery ultrasound and TCD can quantitatively detect the vascular structural and hemodynamic improvements following the endo-vascular stenting, indicating that the combination of carotid artery ultrasound and TCD can be used for the accurate as-sessment and follow up of carotid artery stenting treatment.

Objective To determine the likelihood of G-protein coupled receptor 56 (GPR56 ) induces axonal development and myelination in the corpus callosum of mouse brain.Methods A total of 64 Gpr56 +/-and Gpr56 -/-mice were selected and randomly divided into two groups:Gpr56 +/-group (n=32)and Gpr56 -/-group (n=32).According to number of days after birth,each group was further divided into 4 subgroups including P7d,P14d,P21d and P28d subgroups.Levels of neurofilament-200 (NF -200)and proteolipid protein (PLP ) of myelin basic protein in corpus callosum were measured with immunohistochemistry staining and Western blot in P7d、P14d、P21d、P28d Gpr56 +/- and Gpr56 -/-mice.Gpr56 +/-and Gpr56 -/-neurons were cultured using P1 d Gpr56 +/-and Gpr56 -/-mouse brain.The lengths of Gpr56 +/- and Gpr56 -/-neuronal axon were measured and compared with Image J software. Axonal myelination in the corpus callosum of mouse brain in each group was observed under electronic microscopy and the axonal diameters between subgroups were compared.Results The levels of NF-200 and PLP in the corpus callosum in P7d、P14d、P21d、P28d Gpr56 -/-mice decreased significantly compared with Gpr56 +/- mice.The length of Gpr56 -/-neuronal axon was shortened compared with Gpr56 +/-neuronal axon.The number of myelinated axons was obviously reduced in the corpus callosum in P28d Gpr56 -/-mice.The diameter of axon in the corpus callosum of P28d Gpr56 +/-mouse is longer than that of P28d Gpr56 -/-mouse. Conclusions GPR56 may be involved in axonal development and myelination in the corpus callosum of mouse brain.

OBJECTIVETo explore the involvement of hepatitis B X protein (HBx) in promoter 3 (P3)-driven mRNA overexpression of the insulin-like growth factor II gene (IGF-II) and investigate the underlying epigenetic mechanism.

METHODSLevels of P3 and HBx mRNA and status of P3 methylation were analyzed in human hepatocellular carcinoma (HCC) samples, with and without hepatitis B virus (HBV) infection, using quantitative reverse transcription-PCR and bisulfite sequencing. In addition, the levels of P3 mRNA and P3 methylation were examined in HepG2 cells stably overexpressing HBx (HepG2-HBx). Finally, P3 promoter-luciferase constructs were cotransfected into HepG2 cells along with an HBx-expressing plasmid, and the effects of HBx on transcriptional activity and methylation of P3 were analyzed. Statistical analyses of the data were conducted by chi square test, Fisher's exact test, Student's t-test, Marn-Whitney U test, and Pearson's correlation coefficient test.

RESULTSThe HBV-positive HCC specimens had significantly higher levels of P3 mRNA than the HBV-negative HCC specimens (-9.59 ± 3.22 vs. -12.97 ± 3.08 delta CT; P=0.006) but significantly lower levels of P3 methylation (mean values for the 17 CpG sites (36.9% ± 15.5% vs. 52.1% ± 19.1%; P=0.025). The P3 transcript abundance was positively correlated with the level of HBx expression and negatively correlated with the level of P3 methylation. The epigenetic results from experiments with the HepG2-HBx cells were similar. Transfection of HBx significantly decreased P3 methylation level and increased its activity.

CONCLUSIONHBx expression may promote IGF-II expression by inducing hypomethylation of its P3 promoter in hepatocellular carcinoma.

Carcinoma, Hepatocellular ; genetics ; metabolism ; DNA Methylation ; Epigenesis, Genetic ; Female ; Gene Expression ; Hep G2 Cells ; Humans ; Insulin-Like Growth Factor II ; genetics ; metabolism ; Liver Neoplasms ; genetics ; metabolism ; Male ; Promoter Regions, Genetic ; RNA, Messenger ; genetics ; Trans-Activators ; pharmacology