Objective To investigate the effects of live attenuated measles vaccine Hu191 strain(MV-Hu191)on epithelial mesenchymal transition(EMT),proliferation and migration of 4T1 breast cancer cells.MethodsCCK-8 and clone formation assay were used to analyze the effect of MV-Hu191 on the proliferation of 4T1 cells;The effect of MV-Hu191 on 4T1cell migration was analyzed by cell scratch test;The expression of EMT pathway proteins(MMP-2,MMP-9,E-cadherin)in4T1 cells was detected by Western blot;4T1 tumor-bearing mouse model was established in female BALB/c mice. The model mice were divided into control group(PBS),MV-Hu191(1 × 106TCID50)group and paclitaxel group(15 mg/kg),with 10 mice in each group,and injected into tumor at the dosage of 100 μL every 2 d for 5 times. At 28 d after administration,the effects of MV-Hu191 on survival time,tumorigenicity and metastasis in vivo were observed;The pathological characteristics of lung tissue and tumor tissue were observed by HE staining under microscope;The expression of EMT pathway proteins(MMP-2,MMP-9 and E-cadherin)in tumor tissue was detected by immunohistochemical staining.Results The results of in vitro experiment showed that,compared with the control group,MV-Hu191 inhibited the proliferation and migration of 4T1 cells(F = 2. 811 and 13. 535,P = 0. 001 and 0. 002,respectively),down regulated the expression of MMP-2 and MMP-9(F = 45. 433 and 9. 744,P = 0. 011 and 0. 038,respectively),and up regulated the expression of Ecadherin(F = 7. 001,P = 0. 032);The results of in vivo experiment showed that MV-Hu191 significantly prolonged the survival time of tumor-bearing mice,and decreased the tumor quality(F = 8. 301,P = 0. 003)and the number of pulmonary nodules metastasis compared with the control group(F = 33. 792,P = 0. 000);MV-Hu191 treated tumor tissue gap was small,the cells were round,and the alveolar contour was clearly visible;The expression of MMP-2 and MMP-9 in MVHu191 treated tumor tissue decreased significantly(F = 6. 705 and 9. 047,P = 0. 028 and 0. 023,respectively),while the expression of E-cadherin increased significantly(F = 3. 468,P = 0. 039).ConclusionMV-Hu191 signi-ficantly inhibits the proliferation and migration of 4T1 breast cancer cells,antagonizes the tumorigenicity and lung meta-stasis of 4T1 tumorbearing mice,and prolongs the survival time of mice. The possible mechanism of MV-Hu191 against breast cancer is closely related to the regulation of EMT pathway protein expression.

2019 Novel coronavirus (2019-nCoV) infection has caused a global pandemic. Although researchers have carried out a lot of research on 2019-nCoV, analyzed the molecular structure and conducted evolutionary tree analysis, there is still insufficient understanding of its specific pathogenic mechanism, resulting in the lack of specific and effective therapeutic drugs and method. 2019-nCoV infection can cause inflammation and may deteriorate to acute respiratory distress syndrome (ARDS) and sepsis, which have become the main complication of its death. Therefore, using antiviral and symptomatic treatment with inflammation reduction can have a better therapeutic effect. Mesenchymal stem cells (MSCs) not only have a significant immune-regulation function, but also play a role in regeneration and repair, repairing damaged lungs, so they can be considered as a new effective method for the treatment of coronavirus disease 2019 (COVID-19). This article analyzes the main pathogenic mechanism of 2019-nCoV, and the process of developing into ARDS, combined with the research status of MSCs, to explore its significance and feasibility for the treatment of COVID-19. Finally, it will provide a substantial theoretical basis for clinical treatment now and in the future.

Objective:To construct recombinant influenza viruses expressing Gaussia luciferase (Gluc) with different influenza virus backbones and analyze their growth characteristics, genetic stability, ability to express Gluc and in vitro anti-influenza drug activity. Methods:The C-terminal of PR8NA was modified by inserting the porcine teschovirus-2A autocleavage peptide (P2A) and the Gluc-coding gene. Recombinant viruses, PR8NAGluc/PR8 and PR8NAGluc/WSN, were rescued using the eight-plasmid system of influenza virus reverse genetics, with seven plasmids derived from A/Puerto Rico/8/34(PR8) (H1N1) and A/WSN/1933 (WSN) H1N1. The genetic stability of the recombinant viruses was verified by RT-PCR. The fluorescence activity and the growth kinetics of the two recombinant viruses were compared. The correlation between the fluorescence activity of PR8NAGluc/WSN and median tissue culture infective dose (TCID 50), and the anti-drug activity of PR8NAGluc/WSN against oseltamivir, favipiravir, and Lianhua Qingwen in vitro were also analyzed. Results:The Gluc-expressing recombinant viruses constructed using PR8 and WSN backbones were successfully rescued by reverse genetics. Compared with the PR8 backbone, the WSN backbone significantly improved the fluorescence activity of Gluc. Moreover, the PR8NAGluc/WSN virus expressed stably in embryonated egg, and its replication kinetics was slightly lower than that of wild type. The fluorescence activity of PR8NAGluc/WSN virus had a good correlation with its TCID 50. The PR8NAGluc/WSN virus was sensitive to oseltamivir, favipiravir and Lianhua Qingwen. Conclusions:The recombinant virus with a WSN backbone exhibited higher fluorescence expression intensity as compared with the recombinant virus with a PR8 backbone. This study provided reference for high-throughput screening of anti-influenza drugs and the development of influenza virus vector vaccines.