ABSTRACT
BACKGROUND:Tumor necrosis factor-α-induced protein-8 like-2 (TIPE2), an anti-inflammatory protein, through the T cel receptor (TCR) and TOLL-like receptor signaling pathway, implements negative regulation of adaptive immunity and innate immunity, and thus effectively maintains the stable internal environment of the body. OBJECTIVE:To construct a recombinant adenovirus that can overexpress rat TIPE2 gene. METHODS:TIPE2 cDNA target gene was amplified from rat’s lymphocytes using RT-PCR, cloned into shuttle plasmid pShuttle-clontech, and then subcloned into artificial adenovirus vector AdC68. Hereafter, HEK 293 cel s were transfected to generate a recombinant adenovirus. HEK293A cel s were infected using this recombinant adenovirus, and then TIPE2 gene level was tested by western blot method. RESULTS AND CONCLUSION:Based on results of PCR, digestion identification and sequencing, the obtained cDNA was the coding sequence region of TIPE2. Western blot findings showed that the recombinant adenovirus could overexpress TIPE2 gene. These findings indicate that the recombinant adenovirus is constructed successful y and can express TIPE2 gene stably.
ABSTRACT
Background and purpose: Multidrug resistance (MDR) of tumor cell is the main reason for clinical chemotherapy failure as well as cancer recurrence and metastasis. This study was to construct a lentiveral vector of RNA interference of MDR1 gene and observe its inhibitive role on the expression of MDR1 in A549 and A549/DDP cells. Methods: Oligos of base pairs for hairpin RNA targeting MDR1 were chemically synthesized. Via annealing and inserting them into the down-stream of H1 promoter of linearized pSUPER, we obtained the siRNA constructs for MDR1, which were afterwards transfected into A549, a human lung cancer cell line expressing high level MDR1, the impact of constructs was observed on the expression and interference efficiency of siRNA against MDR1. The effective sequence of siRNA targeting MDR1 gene was confirmed. Both sense and antisence oligo DNA of the targeting sequence was designed, synthesized and cloned into the PTM vector, containing a promoter and a green fluorescent protein (GFP). The resulting lentiviral vector containing MDR1 siRNA was named PTM-siMDR1 and then transfected into A549 and A549/DDP cells after being confirmed by PCR and sequencing. Results: Restriction digestion and DNA sequencing showed that the siRNA constructs for MDR1 were successfully produced and the expressed siRNA could effectively down-regnlate the expression of MDRI. PCR demonstrated that the lentivirus RNAi vector of MDR1 producing PTM-siMDR1 was constructed successfully. The chemosensitivity of A549/DDP cells to cisplatin were enhanced obviously after trartsfection. Conclusion: The lentivirus RNAi vector of MDR1 can significantly revise the resistance ofA549/ DDP cells with eisplatin after infection.
ABSTRACT
BACKGROUND: A great quantity of cell loss in early stage following stem cell transplantation can significantly affect transplantation effect. Presently, it is confirmed that overexpression of AKT1 gene significantly inhibit cell apoptosis. OBJECTIVE: To explore whether AKT1 gene overexpression can block stem cell apoptosis under hypoxic condition following pig autologous bone marrow mesenchymal stem cell (BMSC) transplantation, and the effect of repairing damaged myocardium. DESIGN, TIME AND SETTING: The randomized controlled animal study was performed at the Soochow University from August 2005 to February 2007.MATERIALS: A total of 24 healthy male Meishan pigs were supplied by the Animal Experimental Center of Soochow University. METHODS: The CDS (regulation domin of AKT1) AKT1-cDNA fragment was amplified. Lentivector Packaging Kit was used to transfect BMSCs after synthesized with pCDH1-AKT1 shuttling plasmid. Following BrdU labeling, models of myocardial infarction were constructed by occluding the distal left anterior descending coronary artery in pigs with gelatin sponge. 4 weeks later, pigs were randomly divided into four groups: the model control group, the DMEM group, the BMSCs group, and the AKT-transfected group. In model control group, there was no other injection after occluding the left anterior descending coronary artery. In the DMEM group, 5 mL DMEM was injected into the coronary artery. 5 mL BMSCs (1×10~7 cells) were infused into the coronary artery in the BMSCs group. 5 mL BMSCs transfected with the AKT1 gene were injected in the AKT-transfected group MAIN OUTCOME MEASURES: Western blot analysis and real time RT-PCR were used to test the plasmid. The cardiac function was evaluated by magnetic resonance image. Histological characteristics of the myocardium were observed using immunohistochemistry. Serum vascular endothelial growth factor and transforming growth factor β1 levels were determined by ELISA. RESULTS: AKT1-cDNA was cloned into pCDH1-MCS1-EF1-copGFP and the sequence was confirmed in comparison with the published one. AKT mRNA expression could be detected distinctly 24 and 48 hours after transfecting cells. The expression of AKT1 intensity in MSCs remained strong 2 weeks later with detected by real time RT-PCR and Western blot analysis. AKT1-mRNA transcriptional levels were 120 times of primary cells. Before the cell implantation, the left ventricular end-diastolic dimension increased and the stroke volume decreased in the myocardial infarction hearts. The cardiac function was significantly improved after cell implantation, and the implanted MSCs prevented the infarct region from thinning and expanding, improved contraction and increased perfusion in all groups relative to the control hearts. The left ventricular chamber size was smaller in the hearts with being transplanted cells than that in the control hearts. Moreover, the improvement was even markedly greater in AKT-transfected group (P < 0.05). Hematoxylin-eosin staining results showed that fibering was significant in the model control group and DMEM group. Island-like myocardium was observed in the infarct zone of the BMSCs group and AKT-transfected group, and plenty of small vessels-shape structure was detected in the AKT-transfected group. Immunohistochemistry demonstrated that Von Willebrand Factor (vWF) and Cx-43 expression was determined in the myocardium in the BMSCs group and AKT-transfected group, and the proportion of BrdU and Cx-43-positive cells to BrdU-positive cells was significantly greater in the AKT-transfected group compared with the BMSCs group 4 weeks following transplantation (P < 0.05). Following cell transplantation, vascular endothelial growth factor levels were gradually increased, peaked at 1 week, gradually decreased, and reached a normal level at 4 weeks. Transforming growth factor p1 levels were gradually reduced, and significantly less than the model control group, DMEM group 4 weeks later (P < 0.05), and significantly lower than that pretransplantation (P < 0.05).CONCLUSION: Using lentiviral vector to construct with AKT1 gene could stably make BMSCs overexpress AKT1. The BMSCs engraftment in host myocardium might improve the left ventricle function by attenuating the contractile dysfunction and pathologic thinning in this model of left ventricular wall infarction. AKT1 overexpression can significantly improve cardiac function following infarction.