Department of Medical Oncology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Cancer Biol Ther. 2012 Feb 1;13(3):156-63. doi: 10.4161/cbt.13.3.18697.
Nlp (ninein-like protein), an important molecule involved in centrosome maturation and spindle formation, plays an important role in tumorigenesis and its abnormal expression was recently observed in human breast and lung cancers. In this study, the correlation between overexpression of Nlp and paclitaxel chemosensitivity was investigated to explore the mechanisms of resistance to paclitaxel and to understand the effect of Nlp upon apoptosis induced by chemotherapeutic agents. Nlp expression vector was stably transfected into breast cancer MCF-7 cells. With Nlp overexpression, the survival rates, cell cycle distributions and apoptosis were analyzed in transfected MCF-7 cells by MTT test and FCM approach. The immunofluorescent assay was employed to detect the changes of microtubule after paclitaxel treatment. Immunoblotting analysis was used to examine expression of centrosomal proteins and apoptosis associated proteins. Subsequently, Nlp expression was retrospectively examined with 55 breast cancer samples derived from paclitaxel treated patients. Interestingly, the survival rates of MCF-7 cells with Nlp overexpressing were higher than that of control after paclitaxel treatment. Nlp overexpression promoted G2-M arrest and attenuated apoptosis induced by paclitaxel, which was coupled with elevated Bcl-2 protein. Nlp expression significantly lessened the microtubule polymerization and bundling elicited by paclitaxel attributing to alteration on the structure or dynamics of β-tubulin but not on its expression. The breast cancer patients with high expression of Nlp were likely resistant to the treatment of paclitaxel, as the response rate in Nlp negative patients was 62.5%, whereas was 58.3 and 15.8% in Nlp (+) and Nlp (++) patients respectively (p = 0.015). Nlp expression was positive correlated with those of Plk1 and PCNA. These findings provide insights into more rational chemotherapeutic regimens in clinical practice, and more effective approaches might be developed through targeting Nlp to increase chemotherapeutic sensitivity.
Nlp（九蛋白样蛋白）是一种参与中心体成熟和纺锤体形成的重要分子，在肿瘤发生中发挥重要作用，其异常表达最近在人乳腺癌和肺癌中观察到。在这项研究中，研究了 Nlp 过表达与紫杉醇化疗敏感性之间的相关性，以探讨紫杉醇耐药的机制，并了解 Nlp 对化疗药物诱导的细胞凋亡的影响。稳定转染 Nlp 表达载体至乳腺癌 MCF-7 细胞。通过 MTT 试验和 FCM 方法分析转染 MCF-7 细胞中 Nlp 过表达时的存活率、细胞周期分布和凋亡。免疫荧光法检测紫杉醇处理后微管的变化。免疫印迹分析检测中心体蛋白和凋亡相关蛋白的表达。随后，用 55 例紫杉醇治疗的乳腺癌样本进行 Nlp 表达的回顾性检查。有趣的是，紫杉醇处理后 Nlp 过表达的 MCF-7 细胞的存活率高于对照细胞。Nlp 过表达促进 G2-M 期阻滞，并减弱紫杉醇诱导的凋亡，这与 Bcl-2 蛋白的升高有关。Nlp 表达显著减轻紫杉醇引起的微管聚合和束状，这归因于β-微管蛋白结构或动力学的改变，而不是其表达的改变。Nlp 高表达的乳腺癌患者可能对紫杉醇治疗有耐药性，因为 Nlp 阴性患者的反应率为 62.5%，而 Nlp(+)和 Nlp(++)患者的反应率分别为 58.3%和 15.8%（p=0.015）。Nlp 表达与 Plk1 和 PCNA 的表达呈正相关。这些发现为临床实践中更合理的化疗方案提供了思路，并可能通过靶向 Nlp 来提高化疗敏感性开发更有效的方法。
