长链非编码RNA DLEU1在骨肉瘤中的预后价值分析及机制研究

Prognostic value and mechanism of long non-coding RNA DLEU1 in osteosarcoma

目的:探讨长链非编码RNA(long non-coding RNAs,LncRNA)淋巴细胞白血病缺失基因1(deleted in lymphocytic leukemia 1,DLEU1)在骨肉瘤中的预后价值及机制。方法:回顾性收集2012年1月至2014年12月期间骨科收治的86例骨肉瘤根治术患者组织标本和临床资料,逆转录荧光定量PCR(quantitative reverse transcription-PCR,q RT-PCR)法检测癌组织中LncRNA DLEU1表达,并分成LncRNA DLEU1高低表达两组。将骨肉瘤细胞系HOS分成两组,即下调表达组(si-DLEU1组)及阴性对照组(si-NC),经Lipofectamine^(TM)3000分别转染LncRNA DLEU1 siRNA及阴性对照序列,卡方检验分析LncRNA DLEU1表达与骨肉瘤临床病理因素的关系,Kaplan-Meier法比较LncRNA DLEU1高低表达组骨肉瘤患者总生存率的差异,单因素和多因素分析影响骨肉瘤总生存率的风险因素。Transwell实验测定和比较两组侵袭细胞数。结果:LncRNA DLEU1在癌组织中表达量高于癌旁组织(P<0.001),人骨肉瘤细胞系(MG-63、U-2 OS及HOS)中LncRNA DLEU1表达量高于人成骨细胞系hFOB 1.19(P<0.001)。LncRNA DLEU1表达与Enneking分期(P<0.001)、远处转移(P=0.016)和组织学分级(P=0.028)显著相关。LncRNA DLEU1高表达组1年总生存率低于低表达组(60.5%vs 90.7%,P<0.001)。LncRNA DLEU1高表达组5年总生存率低于低表达组(11.6%vs 32.6%,P<0.001)。Enneking分期、肿瘤大小、远处转移、组织学分级及LncRNA DLEU1表达是影响总生存率的单因素,多因素分析示LncRNA DLEU1高表达[HR=1.948,95%CI(1.141,3.641),P=0.012]及远处转移[HR=4.108,95%CI(2.169,7.780),P<0.001]为影响骨肉瘤患者总生存率的独立风险因子。si-DLEU1组侵袭细胞数显著少于si-NC组,(139±13)vs(357±31),P<0.001。结论:LncRNA DLEU1高表达是影响骨肉瘤患者预后的分子标志物,下调LncRNA DLEU1可抑制骨肉瘤细胞侵袭。

Objective To investigate the prognostic value and mechanism of long non-coding RNA DLEU1(LncRNA DLEU1)in osteosarcoma.Methods The tissue samples and clinical data of 86 patients with osteosarcoma treated by orthopaedic surgery in our hospital from January 2012 to December 2014 were retrospectively collected.The expression of LncRNA DLEU1 in pathological tissues was detected by qRT-PCR,then the patients were divided into high and low expression of LncRNA DLEU1 groups.Osteosarcoma cell line HOS was divided into two groups,down-regulated expression group(si-DLEU1 group)and negative control group(si-NC group).LncRNA DLEU1 siRNA and negative control sequence were transfected by Lipofectamine^(TM) 3000.Chi-square test was used to analyze the relationship between the expression of LncRNA DLEU1 and the clinicopathological factors of osteosarcoma.Kaplan-Meier method was used to compare the difference of the overall survival rate of osteosarcoma patients between the high and low expression groups of LncRNA DLEU1.The risk factors affecting the overall survival rate of osteosarcoma were analyzed by single factor and multifactor analysis.The number of invasive cells in the two groups was determined and compared by Transwell assay.Results The expression of LncRNA DLEU1 in osteosarcoma tissue was higher than that in adjacent tissues(P<0.001).The expression of LncRNA DLEU1 in human osteosarcoma cell lines(MG-63,U-2 OS,and HOS)was significantly higher than that in human osteoblast line hFOB 1.19(P<0.001).The expression of LncRNA DLEU1 was significantly correlated with Enneking stage(P<0.001),distant metastasis(P=0.016),and histological grade(P=0.028).The 1-year overall survival rate of the LncRNA DLEU1 high expression group was significantly higher than that of the low expression group(90.7%vs 60.5%,P<0.001).The 5-year overall survival rate of the LncRNA DLEU1 high expression group was significantly higher than that of the low expression group(32.6%vs 11.6%,P<0.001).Univariate analysis showed that Enneking stage(P<0.001),tumor size(P=0.043),distant metastasis(P<0.001),histological grade(P<0.001),and expression of LncRNA DLEU1(P<0.001)were risk factors for overall survival of osteosarcoma patients.Multivariate analysis showed that high expression of LncRNA DLEU1[HR=1.948,95%CI(1.141,3.641),P=0.012]and distant metastasis[HR=4.108,95%CI(2.169,7.780),P<0.001]were independent risk factors for overall survival of osteosarcoma patients.The number of invasive cells in si-DLEU1 group was significantly lesser than that in si-NC group(139±13 vs 357±31,P<0.001).Conclusion High expression of LncRNA DLEU1 is a molecular marker affecting the prognosis of osteosarcoma patients.Downregulation of LncRNA DLEU1 can inhibit the invasion of osteosarcoma cells.