Objective To explore the inhibitory effect of astragalus polysaccharide (APS) on the proliferation of human erythroleukemia K562 cells and its mechanisms.Methods After K562 cells (purchased from Shanghai cell bank of chinese academy of science) were treated with different concentrations (0 mg/L,100 mg/L,200 mg/L and 400 mg/L) of APS.The influences of APS on the growth rate,doubling time and cell cycle distribution of K562 cells were observed by methyl thiazolyl tetra-zolium assay (MTF) and flow cytometry,respectively.Furthermore,the reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting assay were used to detect the expressions of Cyclin A,Cyclin B,Cyclin E and p21 gene at the mRNA and protein levels,respectively.Results MTT assay findings showed that,compared to the control group (0 mg/L APS),growth rates of K562 cells treated with 100 mg/L,200 mg/L and 400 mg/L APS decreased significantly (all P ＜ 0.01),and the doubling times lengthened significantly (all P ＜ 0.01).Flow cytometry findings revealed that,compared to the control group,the G1 phase cells in K562 cells of APS group increased significantly (P ＜0.01),while the S and G2/M phase cells decreased significantly (all P ＜ 0.01).RT-PCR and Western blotting results indicated that Cyclin B and Cyclin E expression of K562 cells at the mRNA and protein levels in the APS group were significantly lower than those of the control group(all P ＜ 0.01),whereas p21 expression was significantly enhanced at mRNA and protein levels (P ＜ 0.01),and Cyclin A expression was not significantly different at mRNA and protein levels between the 2 groups (all P ＞ 0.05).Conclusions APS could inhibit the proliferation of human erythroleukemia K562 cells.APS could inhibit the proliferation of K562 cells by down-regulating the expression of Cyclin B and Cyclin E and up-regulating the expression of p21.

BACKGROUNDTo investigate the outgrowth inhibition of the HPV16-positive murine lung tumor induced by a modified HPV16 mE6Δ/mE7 recombinant fusion protein vaccine in vivo and provide a new clue for the further immunotherapy.

METHODSFor prophylactic experiments, C57BL/6 mice were immunized with mE6Δ/mE7 fusion protein, and then inoculated with the TC-1 tumor cell, expressing HPV16 E6 and E7 viral proteins. On day 33 after inoculation, the tumor-free mice were re-challenged with a larger dose of TC-1 tumor cells. For therapeutic experiments, mice were vaccinated with mE6Δ/mE7 on days 3 and 14 after tumor cell inoculation. On day 60, the tumor-free mice were re-challenged with a larger dose of tumor cells. Tumor incidence and tumor volume of each group were calculated. MTT method was used to determine the proliferation of lymphocyte.

RESULTSIn the prophylactic experiments, immunization with the mE6Δ/mE7 completely protected the mice against the tumor cell challenge and rechallenge, and all the mice remained tumor free during the 100 days' observation period. In contrast, all the mice in PBS and IFA-treated groups developed tumors within 6-12 days after the first tumor cell inoculation, and died of tumor burden within 30 days. In the therapeutic experiments, the tumor formation rates were 20%, 90% and 60% in vaccinated, PBS and IFA groups respectively. In the next larger dose of tumor cells rechallenge experiment, 87.5% of vaccinated mice still remained tumor free, but all the mice from either PBS or IFA group developed tumors with 4-6 days. In addition, the results of MTT indicated that the proliferation of lymphocytes from vaccinated mice was stronger than that from control group.

CONCLUSIONSThe modified mE6Δ/mE7 can efficiently inhibit the growth of lung cancer in the animal model, indicating that mE6Δ/mE7 protein-based vaccine might show promise for the future clinical application.

OBJECTIVE: To investigate the role and mechanism of the endoplasmic reticulum stress(ERS) pathway of apoptosis mediated by inositol-requiring enzyme-1(IRE1) in the intervention of silicosis fibrosis in rats using polyguanylic acid(PolyG).METHODS: The specific pathogen free adult male SD rats were randomly divided into control group(24rats),silicosis model group(24 rats),PolyG intervention group(16 rats) and PolyG treatment group(16 rats).The silicosis fibrosis rat model was constructed using the single inhalable intratracheal instillation method.The rats in the control group were injected with 1 mL of 0.9% sodium chloride solution.The other 3 groups were given 1 mL of silica suspension at 50.0 g/L mass concentration.The rats in PolyG intervention group on the day of model construction and rats in PolyG treatment group on the 28 th day after model construction were all given PolyG with 2.5 mg/kg body weight by one time tail vein intravenous injection.Eight rats in the PolyG intervention group and PolyG treatment group were sacrificed respectively on day 28 and day 56 after injection.The pathological changes of lung tissue in each group were observed.The expression of glucose regulated protein-78(GRP78),IRE1,CCAAT/enhancer-binding protein homologous protein(CHOP),Casepase-3,Casepase-12,type Ⅰ collagen and type Ⅲ collagen in lung tissue was detected by the Western blot.RESULTS: The histopathology examination results showed that the structure of lung tissue in control group was normal.The alveolar structure of the lung tissue of the silicosis model group was severe,and the fibrous nodules and a large amount of collagen deposition appeared.The silicosis nodules and collagen deposition in PolyG intervention group and PolyG treatment group were less than those in silicosis model group.The expression of GRP78,IRE1,CHOP,Casepase-3,Casepase-12,type Ⅰ collagen and type Ⅲ collagen in silicosis model group was higher than that of control group(P <0.05).The expression of the above 7 proteins in the PolyG intervention group and PolyG treatment group was lower than that of silicosis model group(P<0.05),higher than that of control group(P<0.05),except IRE1 and CHOP in PolyG intervention group.On day 56 after model construction,the expression of GRP78,IRE1,Casepase-3,Casepase-12,typeⅠ collagen and type Ⅲ collagen in PolyG intervention group were lower than that of PolyG treatment group(P<0.05).CONCLUSION: The unfolded protein response of ERS mediated by IRE1 may participate in the process of PolyG the intervention on silicosis fibrosis in rats.PolyG can effectively prevent and treat silicosis fibrosis.Prophylactic administration is recommended.

Purpose To investigate the expression and re-lationship of phosphatidic acid phosphatase 2 domain 1A(PPAPDC1A),also known as phospholipid phosphatase 4(PLPP4),in colorectal cancer(CRC)tissues and different colorectal cancer cells.Methods Immunohistochemical EnVi-sion method was applied to detect the expression of PPAPDC1A in 60 CRC tissues and paired paracancerous tissues.Stable over-expression and silencing cell lines of PPAPDC1A were success-fully constructed by gene transfection,and the effects of this gene on different colorectal cancer cell lines were investigated by CCK-8,Transwell,subcutaneous tumor formation in nude mice and tail vein injection in nude mice.Results PPAPDC1A ex-pression was upregulated in CRC tissues compared with paracan-cerous tissues,and the intensity of PPAPDC1A expression was negatively correlated with cell differentiation(P=0.011).PPAPDC1A stable overexpression and interference cell lines were successfully constructed.The results of in vitro and in vivo experiments showed that the growth rate(SW480-PPAPDC1A,RKO-PPAPDC1A groups:0.38±0.03,0.25±0.01),the number of cells crossing the compartment(SW480-PPAPDC1 A,RKO-PPAPDC1A groups:218.33±7.09,96.33±1.52),the number of clone formation(SW480-PPAPDC1 A,RKO-PPAP-DC1A groups:174.33±5.03,245.00±7.00),the in vivo tumor volume(4.16±0.91),and the number of lung metasta-sis in nude mice(5.1±3.84)were significantly higher in the PPAPDC1A stably overexpressing cell lines compared with the Vector group(P＜0.05).However,the growth rate(SW620-shPPAPDC1A,LOVO-shPPAPDC1A groups:0.14±0.02,0.16±0.05),number of cells crossing the chambers(SW620-shPPAPDC1A,LOVO-shPPAPDC1A groups:13.33±0.57,18.33±0.51),number of clone formation(SW620-shPPAP-DC1A,LOVO-shPPAPDC1A groups:28.33±1.52,8.67± 0.57),tumor volume(0.56±0.21),and number of lung me-tastasis in nude mice(1.2±1.03)were significantly lower(P＜0.05)in the PPAPDC1 A-silenced cell line compared with the NC group.Conclusion Down-regulation of PPAPDC1A expres-sion inhibits the proliferation,invasion,migration and metastatic ability of CRC cells.