AIM:This study examined the inhibitory effect of peiminine on the human colonic adenocarcino-ma cell line SW480 and explored the underlying mechanisms.METHODS:SW480 and human normal colonic epithelial CCD-841CoN cells were treated with different concentrations of peiminine and subjected to the CCK-8 assay to select the optimal treatment time and concentration of the compound.SW480 cell migration and invasion were evaluated by the wound-healing and Transwell assays.Cell cycle progression was analyzed by flow cytometry.The expression levels of cell cycle-related proteins were examined by Western blot.SW480 xenograft tumor model was established in nude mice to ex-amine the effect of peiminine on tumor growth and the expression of cell cycle-related proteins in vivo.RESULTS:Peimi-nine(110 mg/L)significantly inhibited the proliferation of SW480 cells compared with the control group(P<0.01),caused cell cycle arrest at G1 phase,and significantly downregulated the expression of cyclin dependent kinase 2(CDK2),CDK4,CDK6,cyclin D1,p-Rb/Rb,E2F1,E2F3,and E2F4(P<0.05).Peiminine inhibited SW480 xenograft tumor growth,prolonged the survival of model mice,and affected the expression of CDK2,CDK4,CDK6,and cyclin D1 in tu-mor tissues.CONCLUSION:Peiminine promotes G1 phase arrest by down-regulating the expression of CDK2,CDK4,CDK6,and cyclin D1,thereby inhibiting the proliferation of SW480 cells.

In order to develop a positive quality control products for the detection of porcine repro-ductive and respiratory syndrome virus(PRRSV)nucleic acid by real-time fluorescent quantitative PCR(RT-qPCR),the positive quality control products of PRRSV-1 and PRRSV-2 M genes were prepared using armored RNA technology of MS2 phage.PRRSV-1 and PRRSV-2 M genes were amplified,purified and recovered,and ligated into pET28b vector containing MS2 mature enzyme protein gene and capsid protein.After transformed into BL21(DE3),the gene products were in-duced by IPTG and purified by PEG6000 precipitation method to prepare the armored RNA virus-like particles(AR-PRRSV)containing PRRSV M gene.Following the performance evaluation,as the positive quality control products of PRRSV-1 and PRRSV-2 M genes,AR-PRRSV1M and AR-PRRSV2M were calculated using YY/T 1652-2019 standard.Results showed that it had a good u-niformity,stable storage for the armored virus-like particles at-20,4,25 ℃ for 60 d,and 37 ℃ for 30 d.The prepared armored virus-like particles AR-PRRSV1M and AR-PRRSV2M were deter-mined by digital quantitative PCR(ddPCR)after preliminary quantification by RT-qPCR.The 104 copies/μL of AR-PRRSV1M and AR-PRRSV2M ddPCR fixation was(1.33+0.50)× 104 cop-ies/μL.The above results indicates that the AR-PRRSVM can be used as the quality control of the whole detection process(nucleic acid extraction,reverse transcription and RT-qPCR).