| Objective The study was designed to prove the inhibitive effect of APRIL siRNA on the human colorectal cancer in nude mice in vivo and the role of APRIL in the human colorectal cancer.Methods Human CRC model was established in nude mice with the CRC cell line SW480.And the nude mice were treated with APRIL siRNA by the means of intratumoral injection.The nude mice and the tumors were determined carefully.After the tumors were cut out, the tumors were weighted and the tumor inhibitory rate (IR) was estimated. APRIL mRNA expression was surveyed by PCR and APRIL protein expression was detected by immunohistochemistry.To measure the proliferation, the expressions of PCNA protein were detected via ELISA. The activity of metabasis were detected by the expressions of MMPs(MMP-2 and MMP-9). The activity of apoptosis was determined through the detections of bcl-2 and bcl-xl by IHC, and the method of TUNELwere also used to measure the apoptosis. Meanwhile the SW480 cells were stablely transfected with APRIL siRNA(sh637) or pGC-vectors, and then the cell which were transfected or untransfected were transplanted in to BALB/c nude mice s.c., the mude mice and the grafts were reviewed carefully. When the experiment was finished, the tumors were determined similar to the first study.Results The ratio APRIL siRNA compared with 18S were APRIL siRNA group (0.13±0.05)×10-3, the vector group (0.95±0.04)×10-3and the PBS group (0.96±0.05)×10-3, APRIL siRNA decreased the level of APRIL expression, P<0.05. Meanwhile the APRIL protein in APRIL siRNA group was (87.5±5.0) % less than that of the vector and PBS group, P<0.05. APRIL siRNA suppressed the grouth of SW480 tumor, the IR (inhibitve ratio) of APRIL siRNA group was (60.71±1.50) %. The expressions of PCNA and Ki67 in APRIL siRNA group was (78.58±2.50) % and (79.50±1.80) %less than the those of PBS group. Furthermore, the expression of anti-apoptosis proteins bcl-2 and bcl-xl of APRIL siRNA group were (82.6±4.5) % and (79.2±3.5) % less than those of the vector group and PBS group. TUNELsuggested that the apoptosis ratio of APRIL siRNA group was higherly improved than the PBS group. The results of second study suggested that, the time when the tumor of APRIL siRNA stablely transfected SW480 cells apeared was later than the untransfected SW480 cells.The factors (Ki67, PCNA, MMP-2, MMP-9, bcl-2 and bcl-xl) were depressed expressing in the tumors of APRIL siRNA stablely transfected SW480 cells than the untransfected SW480 cells. In a word, the two studies had a similar result that the SW480cells were significantly inhibited because of the APRIL siRNA.Conclusions APRIL targeting gentic silence therapy could gain significantly depression on tumor growth and improvement on apoptosis in human CRC. In a word, APRIL displays important role of human CRC, and it may be thought as one important targeting gene for gene therapy of human CRC. |
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