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Blocking immune checkpoint programmed cell death receptor 1 (PD-1) or programmed death receptor-ligand 1 (PD-L1) can enhance anti-tumor activity of effector T cells. However, the lack of response in many patients to PD-1/PD-L1 therapy remains a question. Improving the immunosuppressive tumor microenvironment (TME) to enhance the efficacy of immune checkpoint inhibitors has become a promising cancer treatment strategy. We constructed a liposome system (PD-L1/siCXCL12-Lp) of CXCL12 siRNA and anti-PD-L1 peptide with matrix metalloproteinases (MMPs) responsiveness, which combined the TME regulation of siCXCL12 and the immune regulation of anti-PD-L1 peptide. All animal experiments were approved by the Biomedical Ethics Committee of Peking University. The authors found that PD-L1/siCXCL12-Lp directly down-regulated the expression of CXCL12 in vitro (33.8%) and in vivo (15.5%). It also effectively increased the ratio of CD8+/Treg by 20.0%, which helped the anti-PD-L1 peptide to better exert its immune effect. The combination therapy significantly inhibited tumor growth (52.08%) with great safety, which explored a new idea for cancer immunotherapy.
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OBJECTIVE:To provide reference for small interfering ribonucleic acid (SiRNA) R&D and registration in China. METHODS:The situation of SiRNA R&D at home and abroad were introduced,and problems encountered in the evaluation and approval process were summed up to put forward suggestions. RESULTS & CONCLUSIONS:SiRNA has developed slowly in Chi-na,with a gap of 5-10 years at least compared with foreign developed countries. The registration category of SiRNA is not clear;applicants lack of guidance documents;production workshop which meet requirement is in shortage;the efficiency of drug registra-tion allows of no optimism. It is recommended that pharmaceutical registration departments carry out the pilot reform for SiRNA registration,publish SiRNA registration guide,relax regulations for IND gradually,encourage applicants to participate in the inter-national multicenter clinical trials in order to improve the efficiency of SiRNA evaluation and approval efficiency.
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Objective To investigate the effects of vascular endothelial growth factor receptor?2 ( VEGFR?2) on proliferation, migration, invasion, and apoptosis after radiotherapy in lung cancer cell line Calu?1, and to explore the probable mechanisms. Methods Small interference RNA ( siRNA )?mediated silencing of VEGFR?2 gene was performed on Calu?1 cells, and the mRNA and protein expression of VEGFR?2 was determined by quantitative real?time PCR and Western blot, respectively. The cells were divided into control group, vascular endothelial growth factor ( VEGF ) group, VEGFR?2 specific siRNA (siKDR) group, and siKDR+VEGF group. The changes in proliferation, migration, and invasion were evaluated by the CCK8 assay, cell scratch wound?healing assay, and transwell migration assay, respectively. The protein expression of VEGFR?2 and proteins in the related downstream signaling pathway was measured by Western blot. Apoptosis in each group was determined after radiotherapy. Results After RNA interference?mediated silencing of VEGFR?2, the mRNA and protein expression of VEGFR?2 was significantly reduced ( P=0. 001,P=0. 000);the proliferation, migration, and invasion of Calu?1 cells were also significantly reduced ( P=0. 000,P=0. 000,P=0. 000);the phosphorylation levels of AKT, ERK 1/2, and p38 were significantly reduced in Calu?1 cells ( P=0. 336,P=0. 986,P=0. 553);the apoptosis in Calu?1 cells was significantly elevated ( P=0. 0012);the protein expression of HIF?1α was significantly inhibited ( P= 0. 016 ) . Conclusions The VEGFR?2 gene silencing significantly inhibits several physiological functions of Calu?1 cells and elevates the apoptosis rate after radiotherapy.
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Objective To investigate the effect of magnetic nanocomposites on proliferation ability of human hepatoma carcinoma (HCC)cells (HepG2 cell line).Methods Leucine-rich repeat-containing G protein-coupled receptor (LGR) 5-small interfering ribonucleic acid (siRNA ) was composited with polyethylenimine wrapped superparamagnetic iron oxide nanoparticle (PEI-SPIO)as the gene vector.PEI group was established by transfecting HepG2 cells when cell fusion reached 60% and SI group was established by transfecting HepG2 cells with equivalent simple LGR5-siRNA.Control (Ctrl)group was also established without transfecting.The efficiency of nanocomposites entering cells was scanned with MRI T2.The inhibition rate of cell proliferation was detected by (cell count kit,CCK)-8 assay.The expression level of messenger ribonucleic acid (mRNA)in LGR5 of cells was detected by reverse transcriptase polymerase chain reaction (RT-PCR)and the protein expressions of LGR5 and cyclin D1 were detected by western blotting.Results MRI T2 signal of HepG2 cells in PEI group decreased significantly.Compared with Ctrl group,the inhibition rate of cell proliferation of HepG2 cells in PEI group was significantly increased.The relative expression of LGR5 mRNA and the relative expression of LGR5 and cyclin D1 protein were both significantly decreased (all in P <0.05),while the corresponding indexes of the cells in SI group had no statistical significance (all in P>0.05 ).Conclusions Magnetic nanocomposites PEI-SPIO composited with LGR5-siRNA may effectively transfect HepG2 cells.Its mechanism may take effect through down-regulating the expression of cyclin D1 to inhibit the proliferation ability of hepatocellular carcinoma HepG2 cells.
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Objective To study the role of src-suppressed C kinase substrate (SSeCKS) in the secretion of tumor necrosis factor (TNF-α) in rat pulmonary micro-vascular endothelial cells (PMVEC) induced by lipopolysaccharide (LPS).Methods Wistar rat PMVEC cultured in vitro were randomly (random number) divided into several groups (n =4) as per exposure to given dosage of LPS for different lengths of time and to different dosages of LPS for given length of time.After PMVEC exposed to 10 mg/L LPS for 1 hour (h),3 h,6 h,12 h and 24 h or 0.1 mg/L,1 mg/L and 10 mg/L LPS for 24 h,the levels of TNF-αin the supernatant of culture medium were examined by the method of enzyme linked immunosorbent assay (ELISA).Another PMVEC was pre-treated by protein kinase C (PKC) inhibitor bis-indolylmaleimide (BIM) for 0.5 h or had the transfection of SSeCKS-specific small interfering RNA (siRNA) for 48 h before 10 mg/L LPS challenge for 24 h,and subsequently the supernatant was also examined by ELISA.One-way analysis of variance (ANOVA) was employed for statistical analysis by SPSS version 10.0 to compare values among all groups.A significant difference was presumed as a probability value ＜ 0.05.Results After PMVEC incubated with 0.1 mg/L,1 mg/L and 10 mg/L LPS for 24 hours,the levels of TNF-αsecreted were (253.70 ± 23.55),(327.88 ± 37.25),(403.20 ± 36.22),respectively,which were higher than that in un-stimulated PMVEC (82.28 ± 22.56,all P =0.000).After 10 mg/L LPS challenge for one hour,the level of TNF-αin the supernatant of PMVEC raised substantially (170.11 ±49.22),peaked at the time of 6 h (404.82 ± 13.78),then persisted at a higher level until 24 h (395.67 ± 36.23) than that in un-stimulated PMVEC (84.60 ± 23.61,P =0.001,0.000,0.000,respectively).After PMVEC pre-incubated with BIM,the level of LPS-induced TNF-αdecreased obviously (200.44 ± 27.39 vs.402.28 ± 31.07,P =0.000).Compared with LPS challenged PMVEC (407.28 ± 32.64),depletion of endogenous SSeCKS in PMVEC after inhibited by SSeCKS-siRNA significantly attenuated increase in the level of LPS-induced TNF-α (195.20 ± 13.28,P =0.000).Conclusions Down-activation of SSeCKS and PKC can inhibit the secretion of TNF-αin PMVEC induced by LPS,relieving the inflammatory response of PMVEC.
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Objective To explore the siRNA as a new antiviral therapy,evaluate the inhibition effect of siRNA based on vector on the HBV of HepG2.2.15 cell,and observe the side effect and toxicity of siRNA vector on cells and the off-target effect of siRNA.Methods Three pairs of siRNA duplexes targeting HBV C gene were designed as double strands,and the duplex were annealed and ligated into the p-Silencer-Cmv 4.1-hygro vector.The ligation products were used to transform JM109 cells.The clones with shRNA were obtained,and the vectors were purified.After the initial identification of the vector with agarose gel and the size of the inserted sequence got examined by native polyacrylamide gel electrophoresis,furthermore the sequencing was further carried out.The recombinant plasmids were purified with ultrapure Midipreps DNA Purification System.Then HepG2.2.15 cells were transfected with the plasmid mixed with siPort XP-1.The expression of HBsAg and HBeAg were detected by immunofluorescence and Western blot,and the HBV RNA was investigated by RT-PCR.Furthermore the real-time quantitive PCR was carried out to detect the changes of HBV DNA.In order to evaluate the toxicity of the shRNA,MTT was used to examine the growth rate and curve of cells.The ELISA was performed to detect the changes of interferon-? (IFN-?).Results The Western blot showed that the HBsAg and HBeAg protein were suppressed with (81.15?0.69)%,(88.12?0.92)% respectively by vector p-C2 on the third day of post-transfection.It had the similar result indicated by immunofluorescence.And the RT-PCR showed that the specific siRNA targeting HBV C gene could markedly suppress the expression of HBV mRNA and the HBV C gene mRNA was inhibited with 96.9%.The real-time quantitive PCR showed that the specific functional siRNA could markedly suppress HBV DNA copy with two orders of magnitude,while the siRNA vector had no effect on the growth of cell showed by MTT detection.Compared with the non-transfected group and p-NC group,the IFN-? level was almost the same with siRNA p-C1,p-C2,p-C3 groups.Conclusions The siRNA based on the expression vector can suppress the expression and replication of HBV in HepG2.2.15 cell.The inhibition effect was specific and had a certain dependency on siRNA concentration.No toxicity effect was found in the study.And the drug resistance wouldn′t happen because the silence was based on the split of gene.