目的 探究土贝母苷乙（tubeimoside Ⅱ，TUB-Ⅱ）抑制结直肠癌生长和转移的作用机制。方法 以人结直肠癌细胞系RKO和SW620为研究对象，检测TUB-Ⅱ对RKO和SW620细胞活力的影响；克隆形成实验检测细胞增殖能力；划痕实验检测细胞迁移能力；Western blotting检测TUB-Ⅱ对RKO和SW620细胞中致死性（2）巨型幼虫同源蛋白2[lethal (2) giant larvae homolog 2，LLGL2]以及上皮-间充质转化（epithelial-mesenchymal transition，EMT）相关蛋白表达的影响；采用免疫共沉淀检测TUB-Ⅱ对LLGL2泛素化的影响。体内构建小鼠皮下瘤模型和结直肠癌肺转移模型，考察TUB-Ⅱ对肿瘤生长和肺转移的影响。结果 TUB-II显著抑制结直肠癌体内外的增殖和转移（P＜0.05、0.01、0.001）。TUB-II显著上调LLGL2的表达（P＜0.05、0.01、0.001），并且抑制磷脂酰肌醇3-激酶（phosphatidylinositol 3-kinase，PI3K）/蛋白激酶B（protein kinase B，Akt）通路的活化（P＜0.05、0.01、0.001），从而抑制肿瘤细胞的增殖和转移。同时TUB-II抑制了双微体同源基因2（murine double minute 2，MDM2）与LLGL2的相互作用来抑制LLGL2的泛素化，从而稳定LLGL2的表达，发挥抗结直肠癌作用。结论 TUB-II抑制结直肠癌的发生发展，其作用机制可能与抑制LLGL2泛素化及PI3K/Akt信号通路相关。

Objective To explore the mechanism of tubeimoside II (TUB-II) in inhibiting the growth and metastasis of colorectal cancer. Methods Human colorectal cancer cell lines RKO and SW620 were used as research subjects, the effect of TUB-II on viability of RKO and SW620 cells was detected. The cell proliferation ability was detected by colony formation assay. The cell migration ability was detected by scratch assay. Western blotting was used to detect the effect of TUB-II on expressions of lethal (2) giant larvae homolog 2 (LLGL2) and epithelial-mesenchymal transition (EMT)-related proteins in RKO and SW620 cells. Co-immunoprecipitation was used to detect the effect of TUB-II on ubiquitination of LLGL2. Subcutaneous tumor model and colorectal cancer lung metastasis model in vivo were constructed to investigate the effect of TUB-II on tumor growth and lung metastasis. Results TUB-II significantly inhibited the proliferation and metastasis of colorectal cancer both in vitro and in vivo (P < 0.05, 0.01, 0.001). TUB-II significantly upregulated the expression of LLGL2 (P < 0.05, 0.01, 0.001) and inhibited the activation of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway (P < 0.05, 0.01, 0.001), thereby suppressing tumor cell proliferation and metastasis. At the same time, TUB-II inhibited the interaction between murine double minute 2 (MDM2) and LLGL2 to suppress the ubiquitination of LLGL2, thereby stabilizing its expression and exerting an anti-colorectal cancer effect. Conclusion TUB-II inhibits the occurrence and development of colorectal cancer, and its mechanism may be related to the inhibition of LLGL2 ubiquitination and PI3K/Akt signaling pathway.

R285.5

天津市自然科学基金资助项目（23JCJQJC00040）