Analysis of hemagglutinin-neuraminidase gene characteristics of human parainfluenza virus type 3 among children with acute respiratory tract infection in Qingdao city / 中华预防医学杂志

The purpose was to discuss the infection status of human parainfluenza virus type 3 (HPIV-3) in children with acute respiratory tract infection(ARTI) in Qingdao, Shandong province, and to analyze the gene characteristics of HPIV-3 hemagglutinin-neuraminidase protein (HN). This study was a cross-sectional study. A total of 1 674 throat swab samples were collected randomly from children with ARTI, in the three hospitals (Qingdao Women and Children's Hospital, West Coast Branch of Affiliated Hospital of Qingdao University, Laoshan Branch of Affiliated Hospital of Qingdao University) from January 2018 to December 2019. Multiplex real-time fluorescence RT-PCR was performed to screen HPIV-3 positive specimens. For HPIV-3 positive specimens, nested PCR was used to amplify the full-length HN gene of HPIV-3. The HN gene was sequenced and compared with the representative strains of HPIV-3 in GenBank, and the phylogenetic tree was established. As results, this study collected 1 674 samples, in which there were 90 HPIV-3 positive samples showed and the detection rate was 5.37%. Among positive specimens, the number of samples from children under 6 years old was 88, accounting for 97.78%. HPIV-3 positive cases were mainly distributed in spring and summer. The full-length sequences of 44 HPIV-3 HN genes were obtained by nested PCR method. Sequence alignment and evolutionary analysis showed that the HPIV-3HN gene belonged to the C3a and C3b branches of C3 genotype, with 30 strains of subtype C3a and 14 strains of subtype C3b. The nucleotide and amino acid homology of the amplified 44 strains of the HPIV-3 HN gene in Qingdao were 97.0%-100.0% and 98.5%-100.0%, respectively. In conclusion, from 2018 to 2019, the C3a and C3b branches of HPIV-3 C3 genotype were circulating prevalent in Qingdao, Shandong province. HN gene variation rate was low, but showed certain regional characteristics in evolution.

CD44 variant increases the invasive ability of human breast cancer cell line MCF-7 cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the impact of a new CD44 variant on invasion of human breast cancer cell line MCF-7, and its possible mechanisms.</p><p><b>METHODS</b>The full length cDNA encoding CD44v17 was obtained from the total RNA isolated from the MCF-7/ADR cells by reverse transcript-polymerase chain reaction (RT-PCR) and subcloned into pMD19-T vector. The CD44v17 gene sequence and reading frame were confirmed by two restriction enzymes and nucleotide sequencing, and then inserted into the eukaryotic expression vector pcDNA3.1. The pcDNA3.1-CD44v17 was transfected into MCF-7 cells by Lipofectamine. The changes of MMP-2 and MMP-9 expression at gene and protein levels were detected by RT-PCR and gelatin zymography, respectively. The number of the cells through the artificial matrix membrane in every group was counted to compare the change of the invasive ability regulated by CD44 variant. The ERK and p-ERK were investigated by Western blotting to approach the molecular mechanisms of MMP-2 and MMP-9 expression regulated by CD44 variant.</p><p><b>RESULTS</b>The new gene sequence was successfully cloned into recombinant vector pcDNA3.1 and identified by the two restriction enzymes. It was confirmed that the reconstructed plasmid contained the sequence of CD44 gene variant which was composed of 1 to 4 exons, 16 to 17 exons, and 1 to 205 bases of 18 exons. The new gene sequence was sent to NCBI for publication and obtained the registered number FJ216964. The up-regulated levels of the CD44 gene mRNA and protein were respectively detected by RT-PCR and flow cytometry in MCF-7 cells transfected with pcDNA3.1-CD44v17. The invasiveness of the cells and the activity of MMP-2 and MMP-9 were clearly activated by hyaluronic acid (HA) treatment and blocked by CD44 neutralizing antibody. Pretreated MCF-7/CD44v17 cells with the neutralizing antibody against CD44 and the inhibitor of MAPKs signaling pathway strongly block the expression of p-ERK.</p><p><b>CONCLUSION</b>A new CD44 gene variant has been found in adriamycin-resistant human breast cancer MCF-7/ADR cells. The expression vector pcDNA3.1-CD44v17 has been cloned and constructed successfully. HA can be integrated with CD44 variant and then regulates the expression of MMP-2 and MMP-9, which increases the invasion ability of MCF-7 cells through the Ras/MAPK signaling pathway.</p>