目的：探讨同源重组修复途径关键调控蛋白SPIDR在小细胞肺癌（small cell lung cancer，SCLC)中的作用与机制。方法：收集2013 年1 月至2015 年1 月上海肺科医院进行肿瘤手术切除、气管镜穿刺的SCLC患者癌组织标本60 例及正常人群肺组织标本44 例，qRT-PCR检测临床组织样本SPIDR mRNA表达水平；经稳定过表达SPIDR 改变NCI-H446 细胞表达水平后，采用MTT、小鼠荷瘤实验等实验方法，在体内、体外探究SPIDR 表达水平对SCLC细胞增殖等影响。结果：吸烟与患者SCLC的发生显著有关（P<0.01）；SPIDR mRNA在SCLC 组织样本中的表达显著低于正常肺组织（P<0.01）。人肺胚成纤维细胞株MRC-5 中SPIDR mRNA和蛋白表达水平明显高于SCLC细胞株NCI-H446（均P<0.05）。在10%胎牛血清常规培养体系中，过表达SPIDR对NCI-H446 细胞增值和化疗药物敏感性无明显影响（均P>0.05），但小鼠荷瘤实验从第9 天开始，过表达SPIDR组（pMSCV-SPIDR）的瘤体积与原始NCI-H446 组和空载体组（pMSCV）开始出现明显差异，第27 天pMSCV-SPIDR 组移植瘤平均体积分别比原始NCI-H446 组与空载体组缩小58.99%和61.84%（均P<0.01）。在含1%~3%胎牛血清的非常规培养体系中，过表达SPIDR 的NCI-H446 细胞增殖速度显著低于原始NCI-H446 组和空载体组（P<0.05 或P<0.01）。结论：SCLC组织中SPIDR表达水平明显低于正常肺组织，过表达SPIDR的NCI-H446 细胞体内及体外低血清含量培养（<3%）生长速度显著低于对照组，表明SPIDR以低血清浓度依赖方式影响SCLC细胞增殖。

Objective: The present study was aimed to explore the role and distinctive mechanism of SPIDR, the key regulatory protein of homologous recombination pathway, in progression of small cell lung cancer (SCLC). Methods: 60 SCLC specimens and 44 normal lung tissues were collected from the patients undergoing tumor resection and bronchoscopic puncture in Shanghai Pulmonary Hospital Affiliated to Tongji University from January 2013 to January 2015. The expression of SPIDR in clinical samples and NCIH446 (SCLC cell line) and MRC-5 (normal cell line) were assayed by Real-time PCR. The role of SPIDR in SCLC was investigated in vivo and in vitro by the expression of SPIDR were artificially modified in NCI-H446. Results: Smoking was significantly associated with the occurrence of SCLC (P<0.01). The expression of SPIDR mRNA in SCLC tissues was lower than that of normal lung tissues (P<0.01), and the SPIDR transcriptional and translational levels of NCI-H446 cells were also lower than that of MRC-5. Although there is no significant changes of cell growth rate and susceptibility to cisplatin and etoposide in the NCI-H446 cells overexpressing SPIDR.However, the volume of xenograft tumors of overexpressed SPIDR group decreased by 58.99% (P<0.01) and 61.84% (P<0.01) than that of the original NCI-H446 cells and the NCI-H446 cells transfected with vector (pMSCV) and the average tumor mass decreased by 61.70% (P<0.01) and 70.25% (P<0.01) respectively. When the fetal bovine serum content in the medium was reduced to 3%, the growth rate of NCI-H446 cells overexpressing SPIDR was 22.33% (P<0.01) and 20.24% (P<0.05) lower than that of the original NCIH446 cells and control group, the similar results were obtained from the 1% serum concentration experiment as well. Conclusion: The expression of SPIDR, the key regulatory protein in the DNA double strand break homologous recombination repair pathway, was significantly suppressed in SCLC tissues, which markedly accelerated the growth of NCI-H446 cells in vivo and reduced the reliance of NCIH446 cells to the serum. The detailed mechanism is worthy of further investigation.

国家自然科学基金委中日韩国际合作资助项目(No.21661140002)