非小细胞肺癌患者血浆可溶性TRAIL对循环ALDH1+肿瘤干细胞样细胞的影响及其机制研究

Lung cancer has become the highest malignant tumor incidence and mortality in China. Cancer stem cells-like cell plays a key role in the tumorigenesis and therapy of non small cell lung cancer (NSCLC). However, the roles of circulating cancer stem cells-like cell in the curative effect and prognosis of the patients with NSCLC remain unclear. Our previous work has successfully isolated aldehyde dehydrogenase 1 (ALDH1) positive circulating cancer cells from the peripheral blood of the patients with NSCLC. Furthermore, we found that the content of sTRAIL (soluble tumor necrosis factor-related apoptosis-inducing ligand, sTRAIL) was negatively correlated with the number of ALDH1+ tumor cells. And the result of MTT assay showed that sTRAIL could inhibit the proliferation of ALDH1+ tumor cells. Based on these findings, we hypothesized that sTRAIL may be applied in the treatment of ALDH1+ cancer stem cells-like cell. We will detect the roles of sTRAIL in ALDH1+ tumor cell by using cell experiments and nude mouse model, and explore the possibility of sTRAIL and ALDH1+ tumor cell are used as treatment and prognosis makers for the patients with NSCLC. This study has important significance to clarify the mechanism of sTRAIL in inhibiting cancer stem cells.

肺癌已成为我国发病率和死亡率最高的恶性肿瘤。肿瘤干细胞样细胞在非小细胞肺癌的发生和治疗过程中起关键作用，但循环肿瘤干细胞样细胞对非小细胞肺癌患者疗效和预后的影响尚不明确。我们前期工作成功地从非小细胞肺癌患者外周血中分离乙醛脱氢酶1 (ALDH1)阳性的循环肿瘤细胞，进一步研究发现可溶性肿瘤坏死因子相关的凋亡诱导配体(sTRAIL)含量与ALDH1+肿瘤细胞数量呈负相关，MTT实验显示sTRAIL能够抑制ALDH1+肿瘤细胞增殖。由此我们提出sTRAIL可能应用于肺癌ALDH1+肿瘤干细胞样细胞治疗这一科学命题。在本项目中，我们将利用细胞实验和裸鼠荷瘤模型进行sTRAIL对ALDH1+肿瘤细胞作用的研究，探索sTRAIL和ALDH1+肿瘤细胞作为非小细胞肺癌患者疗效和预后标志物的可行性。本研究对阐明sTRAIL抑制肿瘤干细胞的分子机制具有重要意义。

循环肿瘤细胞（CTC）对非小细胞肺癌（NSCLC）的诊断和预后有重要意义。醛脱氢酶1（ALDH1）是一种肿瘤干细胞标志物，已用于多种肿瘤，包括NSCLC。肿瘤坏死因子相关凋亡诱导配体（TRAIL）为基础的治疗已被用于许多人类癌症。然而，一些肿瘤对TRAIL诱导的细胞死亡具有耐药性。. 本研究以ALDH1为潜在标记物，从NSCLC患者中分离出循环ALDH1+肿瘤细胞。采用集落形成试验、AnnexinV/PI双染和PI染色检测TRAIL对ALDH1+NSCLC细胞增殖、凋亡和细胞周期的影响。此外，我们建立了异种移植小鼠模型，以确定TRAIL在体内的抗肿瘤作用。最后，利用基因芯片和蛋白质印迹技术检测ALDH1+NSCLC细胞对TRAIL的敏感性。. 与正常对照组相比，NSCLC患者血液中ALDH1+肿瘤细胞的百分比更高。通过Kaplan-Meier分析，ALDH1+细胞与患者的不良预后相关。此外，我们证实TRAIL可以抑制ALDH1+NSCLC细胞的增殖，诱导细胞凋亡和G1阻滞。因此，TRAIL与ALDH1+细胞建立异种移植小鼠模型时肿瘤体积的减小和有利的存活率有关。ALDH1通过激活MEK/ERK信号通路增加ALDH1+NSCLC细胞死亡受体(DR)4和DR5的表达。. 体外和体内实验均表明ALDH1能促进NSCLC细胞的增殖。循环ALDH1+细胞可作为NSCLC的预后指标。ALDH1蛋白通过3’UTR诱导MEK-1mRNA的稳定性并促进其翻译。