小分子RNA干扰靶向巨噬细胞移动抑制因子对大肠癌影响的实验研究

目的 分析靶向巨噬细胞移动抑制因子的小分子干扰RNA(MIFsiRNA)对大肠癌生长与荷瘤小鼠生存质量的影响,并探讨其作用机制.方法 利用盲肠造疝原位接种瘤块法建立大肠癌动物模型.将成功建模后的BALB/C小鼠随机分为3组,每组10只,每周2次分别给予DEPC水、MIFsiRNA(0.15 nmol/g)和非特异性siRNA(0.15 nmol/g)瘤内注射,每天称量各组小鼠的饮水、饮食量和体重,每周测量1次肿瘤体积.4周后处死小鼠,称取肿瘤重量,用ELISA法和免疫组织化学法检测小鼠血清和组织中的MIF水平,分光光度法检测肿瘤组织中Caspase-3蛋白的表达,TUNEL法检测肿瘤组织中凋亡细胞数.结果 MIFsiRNA干预组小鼠血清中MIF表达比其他两组低[(22±6) ng/ml)比(32±8)ng/ml、(33±8) ng/ml,P＜0.01],组织中MIF阳性细胞数比其他两组少[(85±20)/500个比(423±23)/500个、(442±31)/500个,P＜0.01];干预后第3周与第4周MIFsiRNA干预组小鼠肿瘤体积均明显小于其他两组(P＜0.01).处死小鼠后肿瘤重量也明显轻于其他两组[(1.93±0.21)g比(4.40±0.30)g、(5.25±0.44)g,P＜0.01];建模后15～31 d饮水量较其他两组多(P＜0.01),建模后8～31 d饮食量也较其他两组多(P＜0.01),3组小鼠体重变化之间相比差异无统计学意义(P＞0.05);MIFsiRNA干预组小鼠肿瘤组织中Caspase-3蛋白表达比其他两组高[(0.74±0.06) μg比(0.57±0.08)μg、(0.56±0.02)μg,P＜0.01],凋亡细胞数较其他两组多[(12±2)/100个比0、0,P＜0.01].结论 敲低MIF基因表达可以抑制大肠癌的生长,提高荷瘤小鼠的生存质量,其可能的作用机制是激活Caspase-3促进细胞凋亡.

Abstract：

Objective To analyze the effect of siRNA targeting MIF( MIFsiRNA) on the growth of colorectal cancer xenografts and the life quality of tumor-bearing mice.Methods BALB/C mouse model carring colorectal cancer was established.Thirty mice were divided into three groups randomly and managed respectively with intratumor injection of DEPC water, MIFsiRNA(0.15 nmol/g) and non-specific siRNA (0.15 nmol/g), respectively twice a week for consecutively 4 weeks.Drinking water, fodder consumed and body weight was recorded daily, and tumor volume was measured once a week.Mice were sacrificed after four weeks.ELISA and immunohistochemistry were used to detect the expression of MIF in serum and in tumor tissues.Spectrophotometric detection was used to detect caspase-3 protein.TUNEL was used to detect apoptotic cells.Results MIF expression in serum in MIFsiRNA group was lower than the other two groups [(22 ± 6) ng/ml vs (32 ± 8) ng/ml and (33 ± 8) ng/ml, P ＜ 0.01]; MIF expression in tissues was less than the other two groups [(85 ± 20) /500 vs.(423 ± 23) /500 and (442 ± 31) /500, P ＜ 0.01]; Tumor was smaller than the other two groups at third and fourth week (P ＜ 0.01) ; Tumor weight was significantly less than the other two groups [(1.93 ±0.21) g vs (4.40 ±0.30) g and (5.25 ±0.44) g, P＜0.01]; Mice in MIFsiRNA group were healthier than the other two groups as judged by water and fodder consumption (P ＜ 0.01 ) , while weight change was not significantly different among the three groups ( P ＞ 0.05 ).Caspase-3 protein in tissues was higher than the other two groups [(0.74 ±0.06) μg vs (0.57 ±0.08) μg and (0.56 ±0.02) μg, P ＜0.01]; Apoptosis cells in tissues were higher than the other two groups [(12 ± 2)/ 100 个vs 0 and 0, P ＜ 0.01].Conclusions Knockdowning MIF gene expression inhibits the growth of colorectal cancer xenografts and improves life quality of tumor-bearing mice, possibly by a mechanism in which MIFsiRNA activates caspase-3 promoting cell apoptosis.

The effect of siRNA targeting MIF on the growth of colorectal cancer xenografts and the life quality of tumor-bearing mice

Objective To analyze the effect of siRNA targeting MIF( MIFsiRNA) on the growth of colorectal cancer xenografts and the life quality of tumor-bearing mice.Methods BALB/C mouse model carring colorectal cancer was established.Thirty mice were divided into three groups randomly and managed respectively with intratumor injection of DEPC water, MIFsiRNA(0.15 nmol/g) and non-specific siRNA (0.15 nmol/g), respectively twice a week for consecutively 4 weeks.Drinking water, fodder consumed and body weight was recorded daily, and tumor volume was measured once a week.Mice were sacrificed after four weeks.ELISA and immunohistochemistry were used to detect the expression of MIF in serum and in tumor tissues.Spectrophotometric detection was used to detect caspase-3 protein.TUNEL was used to detect apoptotic cells.Results MIF expression in serum in MIFsiRNA group was lower than the other two groups [(22 ± 6) ng/ml vs (32 ± 8) ng/ml and (33 ± 8) ng/ml, P ＜ 0.01]; MIF expression in tissues was less than the other two groups [(85 ± 20) /500 vs.(423 ± 23) /500 and (442 ± 31) /500, P ＜ 0.01]; Tumor was smaller than the other two groups at third and fourth week (P ＜ 0.01) ; Tumor weight was significantly less than the other two groups [(1.93 ±0.21) g vs (4.40 ±0.30) g and (5.25 ±0.44) g, P＜0.01]; Mice in MIFsiRNA group were healthier than the other two groups as judged by water and fodder consumption (P ＜ 0.01 ) , while weight change was not significantly different among the three groups ( P ＞ 0.05 ).Caspase-3 protein in tissues was higher than the other two groups [(0.74 ±0.06) μg vs (0.57 ±0.08) μg and (0.56 ±0.02) μg, P ＜0.01]; Apoptosis cells in tissues were higher than the other two groups [(12 ± 2)/ 100 个vs 0 and 0, P ＜ 0.01].Conclusions Knockdowning MIF gene expression inhibits the growth of colorectal cancer xenografts and improves life quality of tumor-bearing mice, possibly by a mechanism in which MIFsiRNA activates caspase-3 promoting cell apoptosis.