Li Tianxiao, Yuan Gang, Zhang Lin, Ye Lijun, Li Shuxia, Fan Yuhua, Sun Jian
Department of Clinical Research, Sun Yat‑sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060, P.R. China.
Department of Geriatrics, The First Affiliated Hospital, Sun Yat‑sen University, Guangzhou, Guangdong 510080, P.R. China.
Mol Med Rep. 2015 Nov;12(5):6976-84. doi: 10.3892/mmr.2015.4299. Epub 2015 Sep 8.
Colorectal cancer (CRC) is a worldwide malignancy of high incidence and mortality. At present, there is a lack of effective drugs against CRC. The B‑cell leukemia/lymphoma 2 (Bcl‑2) protein family members are considered to be closely associated with tumorigenesis and the chemoresistance of CRC. As a novel gossypol derivative targeting antiapoptotic proteins of the Bcl‑2 family, apogossypolone (ApoG2) exhibits antitumor properties in various cancer types, although its effects against CRC remain to be fully elucidated. In the present study, the cytotoxicity of ApoG2 in vitro on CRC cells was investigated, with the aim of elucidating the underlying mechanism. Using an MTT assay, ApoG2 was revealed to inhibit the growth of the HT29, SW480 and HCT116 CRC cell lines in a dose‑ and a time‑dependent manner. Hoechst staining revealed that ApoG2 induced CRC cell apoptosis, marked by morphological changes, including cell shrinkage and nuclear fragmentation. Flow cytometric analysis also detected a higher apoptotic ratio following treatment with ApoG2. The ratio was dependent upon the concentration of ApoG2, which the cells were exposed to, and the duration of the exposure. Western blot analysis and immunoprecipitation experiments revealed that ApoG2 treatment led to the downregulation of the protein expression of Mcl‑1, and the interruption of the binding of Mcl‑1 to the protein Bax. Furthermore, treatment with ApoG2 led to the release of cytochrome c into the cytoplasm and the activation of caspases 3 and 7. The present study revealed that ApoG2 inhibited the proliferation of the CRC cell lines through mitochondrial signaling pathway‑dependent apoptosis, which may be associated with the disruption of the function of the Mcl‑1 protein by ApoG2.
结直肠癌(CRC)是一种在全球范围内发病率和死亡率都很高的恶性肿瘤。目前,缺乏有效的抗CRC药物。B细胞淋巴瘤/白血病-2(Bcl-2)蛋白家族成员被认为与CRC的肿瘤发生和化疗耐药密切相关。作为一种靶向Bcl-2家族抗凋亡蛋白的新型棉酚衍生物,脱甲基棉酚(ApoG2)在多种癌症类型中均表现出抗肿瘤特性,尽管其对CRC的作用仍有待充分阐明。在本研究中,研究了ApoG2在体外对CRC细胞的细胞毒性,旨在阐明其潜在机制。使用MTT法检测发现,ApoG2以剂量和时间依赖性方式抑制HT29、SW480和HCT116 CRC细胞系的生长。Hoechst染色显示,ApoG2诱导CRC细胞凋亡,其形态学变化包括细胞收缩和核碎片化。流式细胞术分析也检测到ApoG2处理后凋亡率更高。该比率取决于细胞所接触的ApoG2浓度以及接触持续时间。蛋白质印迹分析和免疫沉淀实验表明,ApoG2处理导致Mcl-1蛋白表达下调,并中断Mcl-1与蛋白Bax的结合。此外,ApoG2处理导致细胞色素c释放到细胞质中,并激活半胱天冬酶3和7。本研究表明,ApoG2通过线粒体信号通路依赖性凋亡抑制CRC细胞系的增殖,这可能与ApoG2破坏Mcl-1蛋白的功能有关。