【Objective】To testify the silence efficiency of a lentivirus-mediated vector for RNA interference (RNAi) targeting clusterin (CLU) and the influence of proliferation and apoptosis in human renal cancer cell line 786-O. 【Methods】 Lentiviral vectors for different short hairpin RNAs targeting the coding region of human CLU mRNA (CLU-RNAi-LV) were constructed. The recombinant lentiviral vectors were harvested from 293T cells and were used to transfect human renal cancer cell lines 786-O. There were five groups: CLU-RNAi-LV1 (KD1)

CLU-RNAi-LV2 (KD2)

and CLU-RNAi-LV3 (KD3) were renal cancer cells with lentiviral infection targeting CLU gene

NC were renal cancer cells with negative lentiviral infection

and CON were renal cancer cells 786-O as blank control group. Expression of CLU mRNA and protein in the cells were detected by real time-PCR and Western blot

respectively. After that

MST-1

wound healing assay

flow cytometry were applied to examine the effect of CLU silence on the proliferation and apoptosis in 786-O cells.【Results】 The lentiviral vectors CLU-RNAi-LV were constructed and confirmed by DNA sequencing. CLU-RNAi-LV resulted in obviously reduced expression of CLU mRNA and protein in the human renal cancer cell line 786-O compared with the control vector. Real time-PCR showed that the CLU mRNA expression levels in KD1

KD2 and KD3 group after CLU-RNAi-LV infection by different MOI were down-regulated by 69.4%

58.7% ~ 96.5% and 0 respectively compared with NC group.Western blot showed that the CLU protein expression levels in KD1

KD2 and KD3 group decreased by 35.24%

46.26%

and 58.91%

respectively compared to CON group

and the expression of CLU gene in 786-O cells was significantly inhibited in KD3 group. The wound healing assay showed the cell migration distance in KD3(si-CLU) group (408.43 ± 25.92) was less than NC (101.35 ± 6.05) and CON group (68.13 ± 6.64)

with statistically significant differences among groups (P < 0.05). WST-1 assay showed cell growth rate at 72h after transfection was significantly decreased in KD3 (si-CLU) group compared to NC and CON group (P < 0.05) with statistically significant differences among groups (P < 0.05). FCM showed the apoptosis rate in KD3 (si-CLU)

NC and CON group was (6.23 ± 2.51)%

(1.05 ± 0.30)%

and (1.17 ± 0.29)%

respectively. The apoptosis rate in KD3 (si-CLU) group was increased compared to NC and CON group

with statistically significant differences among groups (P < 0.05). The proliferation and migration of 786-O cell line were suppressed and apoptosis of 786-O cell line was promoted. 【Conclusion】 siRNA sequences and renal cancer cell line 786-O cell with stable interference of CLU gene expression were filtered out. Lentivirus-mediated CLU RNAi can specifically inhibit endogenous CLU expression in human renal carcinoma cell line 786-O. CLU-RNAi-LV can also effectively inhibit proliferation and promote apoptosis in human renal carcinoma cell line 786-O.