Woo Chern Chiuh, Hsu Annie, Kumar Alan Prem, Sethi Gautam, Tan Kwong Huat Benny
Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
PLoS One. 2013 Oct 2;8(10):e75356. doi: 10.1371/journal.pone.0075356. eCollection 2013.
Due to narrow therapeutic window of cancer therapeutic agents and the development of resistance against these agents, there is a need to discover novel agents to treat breast cancer. The antitumor activities of thymoquinone (TQ), a compound isolated from Nigella sativa oil, were investigated in breast carcinoma in vitro and in vivo. Cell responses after TQ treatment were assessed by using different assays including MTT assay, annexin V-propidium iodide staining, Mitosox staining and Western blot. The antitumor effect was studied by breast tumor xenograft mouse model, and the tumor tissues were examined by histology and immunohistochemistry. The level of anti-oxidant enzymes/molecules in mouse liver tissues was measured by commercial kits. Here, we show that TQ induced p38 phosphorylation and ROS production in breast cancer cells. These inductions were found to be responsible for TQ's anti-proliferative and pro-apoptotic effects. Moreover, TQ-induced ROS production regulated p38 phosphorylation but not vice versa. TQ treatment was found to suppress the tumor growth and this effect was further enhanced by combination with doxorubicin. TQ also inhibited the protein expression of anti-apoptotic genes, such as XIAP, survivin, Bcl-xL and Bcl-2, in breast cancer cells and breast tumor xenograft. Reduced Ki67 and increased TUNEL staining were observed in TQ-treated tumors. TQ was also found to increase the level of catalase, superoxide dismutase and glutathione in mouse liver tissues. Overall, our results demonstrated that the anti-proliferative and pro-apoptotic effects of TQ in breast cancer are mediated through p38 phosphorylation via ROS generation.
由于癌症治疗药物的治疗窗口狭窄以及对这些药物产生的耐药性，需要发现新型药物来治疗乳腺癌。对从黑种草油中分离出的化合物百里醌（TQ）的抗肿瘤活性进行了体外和体内乳腺癌研究。通过使用包括MTT法、膜联蛋白V-碘化丙啶染色、Mitosox染色和蛋白质印迹等不同检测方法评估TQ处理后的细胞反应。通过乳腺癌异种移植小鼠模型研究抗肿瘤作用，并通过组织学和免疫组织化学检查肿瘤组织。使用商业试剂盒测量小鼠肝脏组织中抗氧化酶/分子的水平。在此，我们表明TQ诱导乳腺癌细胞中的p38磷酸化和活性氧（ROS）产生。发现这些诱导作用是TQ抗增殖和促凋亡作用的原因。此外，TQ诱导的ROS产生调节p38磷酸化，但反之则不然。发现TQ治疗可抑制肿瘤生长，并且与阿霉素联合使用可进一步增强这种作用。TQ还抑制乳腺癌细胞和乳腺癌异种移植中抗凋亡基因如XIAP、生存素、Bcl-xL和Bcl-2的蛋白表达。在TQ处理的肿瘤中观察到Ki67降低和TUNEL染色增加。还发现TQ可提高小鼠肝脏组织中过氧化氢酶、超氧化物歧化酶和谷胱甘肽的水平。总体而言，我们的结果表明，TQ在乳腺癌中的抗增殖和促凋亡作用是通过ROS生成介导的p38磷酸化实现的。
