摘要目的 观察在体外实验中,Toll样受体4(TLR4)对人结直肠癌细胞HT29和SW480酰基辅酶A胆固醇酰基转移酶1(ACAT1)表达的影响及其癌细胞增殖、侵袭和迁移的影响.方法 通过反转录-聚合酶链反应(RT-PCR)和Western blot法检测TLR4和ACAT1在结直肠癌组织和细胞株中的表达水平.利用TLR4小干扰RNA(siRNA)特异性沉默TLR4后,采用细胞计数试剂盒(CCK-8)和Transwell小室检测并评估人结直肠癌细胞HT29和SW480的增殖、侵袭和迁移能力的变化.采用RT-PCR和Western blot法研究TLR4和ACAT1之间的关系.结果 相对于癌旁组织,结直肠癌组织TLR4和ACAT1 mRNA和蛋白表达明显增高(TLR4 mRNA:2.395 0±0.247 7比1.093 0 ±0.075 8,P=0.000;ACAT1 mRNA:2.1960 ±0.189 5比1.093 0±0.075 8,P=0.000);人结直肠癌细胞株HT29、SW480、Caco-2和DLD-1相对于正常人结直肠细胞株FHC TLR4和ACAT1表达也均表达上调.TLR4 siRNA抑制TLR4的表达,可抑制结直肠癌细胞的增殖、侵袭和迁移.同时,TLR4 siRNA在结直肠癌细胞HT29中可降低ACAT1的表达(mRNA:0.3500±0.1457比1.0170±0.1450,P=0.032;蛋白:0.523 3 ±0.052 1比1.1400±0.105 8,P=0.006),而利用ACAT1的慢病毒基因过表达载体pLV-Neo-ACAT1使ACAT1过表达后,可解除TLR4 siRNA对结直肠癌的这一抑制作用.结论 TLR4 siRNA在结直肠癌细胞中通过影响ACAT1的表达以抑制结直肠癌细胞的增殖、侵袭和迁移.

abstractsObjective Toll-like receptor 4 (TLR4) is involved in tumor development.Numerous studies have confirmed that TLR4 mediates processes in tumorigenesis,for example,inflammation,proliferation and invasion.However,the effects of TLR4 on colorectal cancer development have not been fully elucidated.The present study aimed to evaluate the effects and mechanisms of TLR4 on colorectal cancer development.Methods The expression of TLR4 and acyl coenzyme A cholesterol acyltransferase 1 (ACAT1) in colorectal cancer tissues and cell lines was detected using reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting.Cell counting kit-8 (CCK-8) and Transwell assays were used to evaluate the effects of TLR4 silencing on cell proliferation,migration and invasion in HT29 and SW480.RT-PCR and Western blotting were used to determine the regulation between TLR4 and ACAT1.Results Both TLR4 and ACAT1 were highly expressed in colorectal cancer tissues (TLR4 mRNA:2.395 0 ± 0.247 7 and 1.093 0 ± 0.075 8,P =0.000;ACAT1 mRNA:2.196 0 ± 0.189 5 and 1.093 0 ± 0.075 8,P =0.000) and cell lines.Inhibition of TLR4 suppressed cell proliferation,migration and invasion in HT29 and SW480.TLR4 small interfering RNA (siRNA) decreased ACAT1 expression in HT29 (mRNA:0.350 0 ± 0.145 7 and 1.017 0± 0.145 0,P =0.032;Protein:0.523 3 ± 0.052 1 and 1.140 0 ±0.105 8,P=0.006),and that overexpression of ACAT1 by pLV-Neo-ACAT1 abolished the effects of TLR4 siRNA on colorectal cancer cell lines.Conclusion TLR4 siRNA inhibits cell proliferation,migration and invasion by suppressing ACAT1 expression,suggesting that TLR4 may be a potential therapeutic target for the treatment of colorectal cancer.