目的·研究海绵来源的倍半萜胺醌类化合物smenospongine（SME）对非小细胞肺癌（non-small cell lung cancer，NSCLC）细胞A549及其顺铂耐药株A549/DDP的抗肿瘤活性及作用机制。方法·利用2种细胞（母本细胞A549和顺铂耐药细胞A549/DDP）作为研究模型，采用CCK-8实验检测2株细胞对一线化学治疗药物的半抑制浓度（half maximum inhibitory concentration，IC₅₀）以验证A549/DDP多药耐药的情况；通过克隆形成实验检测SME对母本及耐药细胞增殖的影响，同时采用Transwell侵袭实验以及蛋白质印迹法（Western blotting）检测SME对A549/DDP上皮间质转化（epithelial to mesenchymal transition，EMT）的影响；应用Western blotting和实时荧光定量PCR（quantitative real-time PCR，qRT-PCR）检测2株细胞中受到SME调节的多药耐药基因的蛋白和mRNA表达水平，探讨其耐药分子机制；进一步采用Western blotting检测SME对多药耐药蛋白ATP结合盒蛋白G超家族成员2（ATP-binding cassette superfamily G member 2，ABCG2）上游蛋白的影响；通过流式细胞技术检测SME对母本细胞和顺铂耐药株细胞周期的影响，同时应用TUNEL（TdT-mediated dUTP Nick-end labeling）染色以及Western blotting检测SME对2株细胞凋亡的影响。结果·与母本细胞相比，顺铂耐药株A549/DDP细胞对顺铂表现出显著耐药性，同时对多种临床一线肺癌化学治疗药物表现出多药耐药的特征；SME显著抑制A549和A549/DDP的增殖、克隆形成，同时抑制耐药株的EMT；通过筛选多药耐药蛋白发现，SME显著下调ABCG2的蛋白以及mRNA表达；SME可抑制ABCG2上游的表皮生长因子受体（epidermal growth factor receptor，EGFR）/丝氨酸苏氨酸蛋白激酶（serine/threonine kinase，Akt）信号通路，进而下调ABCG2，并上调FoxO1；SME诱导母本细胞和耐药株细胞周期阻滞在G0/G1期，同时诱导2株细胞凋亡。结论·SME作为抑制NSCLC耐药的新小分子化合物通过抑制EGFR-Akt信号通路，下调ABCG2蛋白、上调FoxO1蛋白，进而抑制A549和A549/DDP的细胞活力，抑制耐药株的EMT，最终促进细胞凋亡。

Objective ·To explore the antitumor activities and mechanisms of the sesquiterpene amine quinone compound smenospongine (SME) in non-small cell lung cancer (NSCLC) cell line A549 and cisplatin-resistant cell line A549/DDP. Methods ·Parental cell A549 and its cisplatin-resistant cell A549/DDP were used as research models. CCK-8 assay was used to detect the half maximum inhibitory concentration (IC₅₀) of the two cell lines treated with first-line chemotherapeutic drugs, in order to verify the multidrug resistance of A549/DDP. Colony formation assay was used to detect the effect of SME on the proliferation of parental and drug-resistant cells. Transwell invasion assay and Western blotting were used to detect the effect of SME on epithelial to mesenchymal transformation (EMT) of A549/DDP; Western blotting and quantitative real-time PCR (qRT-PCR) were used to detect the protein and mRNA expression levels of multidrug resistance genes regulated by SME in two cell lines and the molecular mechanism of drug resistance. Furthermore, Western blotting was used to detect the effect of SME on the upstream protein of multidrug resistance protein, ATP-binding cassette superfamily G member 2 (ABCG2), and flow cytometry was used to detect the effect of SME on the cell cycle of parental and cisplatin-resistant cells. TdT-mediated dUTP Nick-end labeling (TUNEL) and Western blotting were used to detect the effect of SME on apoptosis of the two cell lines. Results ·Compared with parental cells, cisplatin-resistant A549/DDP cells showed significant resistance to cisplatin and showed multidrug resistance to the first-line chemotherapy drugs used on lung cancer. SME markedly inhibited the proliferation and clone formation of A549 and A549/DDP as well as the EMT of drug-resistant cell. SME notably down-regulated the expression of ABCG2 protein and mRNA, and inhibited the epidermal growth factor receptor (EGFR)-serine/threonine kinase (Akt) signal pathway upstream of ABCG2, which thereby down-regulated ABCG2, and positively regulated FoxO1. SME induced G0/G1 arrest and induced apoptosis of both cells. Conclusion ·As a new small molecular compound in overcoming the drug resistance of NSCLC, SME inhibits the cell viability of A549 and A549/DDP by restraining EGFR-Akt signal pathway which thereby down-regulates ABCG2, positively regulates FoxO1 and inhibits EMT of A549/DDP, which finally leads to apoptosis.