Expression of topoisomerase II alpha in human colorectal carcinoma and its significance / 南方医科大学学报

<p><b>OBJECTIVE</b>To detect the correlation between the expression of topoisomerase 2 alpha (TOP2A) and the biological behaviors of human colorectal carcinoma.</p><p><b>METHODS</b>Immunohistochemistry and real-time RT-PCR were used to detect the expression of TOP2A in colorectal carcinomas and normal mucosa.</p><p><b>RESULTS</b>The protein and mRNA expressions of TOP2A in the metastatic lymph nodes were significantly higher than those in matched primary lesions and normal tissues (P<0.05). No significant difference was found in TOP2A expressions between normal mucosa and colorectal carcinomas. The protein and mRNA expressions of TOP2A were significantly correlated to the lymph node metastasis and invasion depth (P<0.05), but not to the differentiation of the tumor (P>0.05).</p><p><b>CONCLUSION</b>TOP2A plays an important role in the invasion and metastasis of the colorectal carcinomas, and may serve as a valuable indicator for the diagnosis, treatment and the prognostic evaluation of the malignancy.</p>

A new reagent for methemoglobin reduction test / 南方医科大学学报

<p><b>OBJECTIVE</b>To develop a new stable and efficient reagent for methemoglobin reduction test.</p><p><b>METHODS</b>The results of methemoglobin reduction test using the new reagent were compared with those by G6P/6PG ratio method and classic methemoglobin reduction test.</p><p><b>RESULTS</b>The new reagent was stable for at least 6 months at room temperature and 12 months at 2-8 degrees celsius;. The results of the test using this new reagent were stable and reliable.</p><p><b>CONCLUSION</b>The new reagent for methemoglobin reduction test allows easy operation with well reproducible results and can be used in clinical screening of glucose-6-phosphate dehydrogenase deficiency.</p>

Expression of the zinc finger transcriptional factor Snail in colorectal carcinoma and its significance / 南方医科大学学报

<p><b>OBJECTIVE</b>To study expression of the zinc finger transcriptional factor Snail in colorectal carcinoma and its significance.</p><p><b>METHODS</b>Expressions of Snail in colorectal carcinoma SW480 and SW620 cells were assayed by immunocytochemistry and immunofluorescent cytochemistry. The paraffin-embedded specimens from 68 cases of colorectal carcinoma and its corresponding adjacent tissues, 33 cases of adenoma and 35 cases of metastatic lymph nodes were also examined for Snail expressions using immunohistochemistry.</p><p><b>RESULTS</b>Snail protein was located mainly in the cell nucleus of SW480 and SW620 cells. The expressions of PRL-3 protein in the specimens of colorectal carcinoma, normal mucosa, adenoma and metastatic lymph nodes were significantly different (Chi(2)=92.852, P=0.000). In the adenoma tissues, the expression was significantly higher than that in normal mucosa (Z=-2.902, P=0.004), the metastatic lymphnodes had significantly higher expressions than the primary colorectal carcinomas (Z=-4.951, P=0.000), which, in turn, showed significantly higher expression than the adenoma tissues (Z=-3.572, P=0.000). Significant correlation of Snail expression was found to the progression and metastasis of colorectal carcinoma (Z=-2.043, P=0.041).</p><p><b>CONCLUSION</b>The expression of Snail is significantly correlated to genesis, progression and metastasis of colorectal carcinoma.</p>

Construction of a lentiviral vector for RNA interference of human CDH22 gene and its gene silencing effect in SW480 cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct a lentiviral expression vector for RNA interference of human CDH22 gene, and assess its gene silencing effect in colorectal cancer cells to provide a basis for investigating the role of CDH22 gene in the signaling pathway involved in human colorectal carcinoma metastasis.</p><p><b>METHODS</b>Human CDH22 gene short hairpin RNA (shRNA) sequence was designed using a software available on-line. After synthesis and annealing, the double-stranded oligonucleotides (dsOligoe) were cloned into the pENTR(TM)/U6 plasmid followed by sequence analysis. A positive clone was subcloned into pLenti6/BLOCK-iT(TM)-DEST vector and transformed into stb13 competent cells, with also verification by sequencing. The recombinant lentivirus was harvested from 293FT cells contransfected with the positive recombined plasmid and lentiviral packing materials. SW480 cells were infected with the recombinant lentivirus and the cells with stable CDH22 knock-down were screened by blasticidin selection. CDH22 expression in the cells was determined by real-time reverse transcription-polymerase chain reaction.</p><p><b>RESULTS</b>A recombinant lentiviral vector expressing shRNAs against CDH22 gene was obtained and confirmed by DNA sequencing. Fifteen clones of SW480 cells infected with the recombinant lentivirus were selected, and clone 11 exhibited substantial knock-down of CDH22 mRNA expression.</p><p><b>CONCLUSION</b>The lentiviral shRNA expression vector targeting human CDH22 gene capable of stable CDH22 gene knock-down in SW480 cells has been successfully constructed, which provides a basis for further study of the relationship between human colorectal carcinoma and CDH22 gene.</p>

Preliminary study of PRL-3 gene promoter binding sites of Snail in SW480 cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To identify the region in PRL-3 gene promoter where the transcriptional factor Snail can bind.</p><p><b>METHODS</b>PRL-3 promoter and the possible binding sites of the transcription factors were analyzed by bioinformatical methods. Chromatin immunoprecipitation and PCR were performed using the antibody specific for Snail to verify the binding of Snail to PRL-3 promoter.</p><p><b>RESULTS</b>According to the prediction by TRED, a promoter prediction software, PRL-3 gene promoter was located between -700 bp to 299 bp of PRL-3 gene. Many possible transcription factor binding sites such as for Snail, n-MYC, ARNT, E74A, NF-kappaB, NRF-2 and AML-1 were predicted by Consite, a promoter analysis web system. Interestingly, a 5'-CACCTG-3' core sequence and other related sequences of Snail binding sites were found in the promoter region of PRL-3 genes by Consite software. Two regions in PRL-3 promoter were validated to allow binding of Snail by chromatin immunoprecipitation analysis of SW480 cells.</p><p><b>CONCLUSIONS</b>Snail regulates the activity of PRL-3 gene by binding to the promoter of PRL-3 gene in SW480 cells.</p>