Secretion of annexin A3 from ovarian cancer cells and its association with platinum resistance in ovarian cancer patients

Early detection of resistance to platinum-based therapy is critical for improving the treatment of ovarian cancers. We have previously found that increased expression of annexin A3 is a mechanism for platinum resistance in ovarian cancer cells. Here we demonstrate that annexin A3 can be detected in the culture medium of ovarian cancer cells, particularly these cells that express high levels of annexin A3. Levels of annexin A3 were then determined in sera from ovarian cancer patients using an enzyme-linked immunosorbent assay. Compared with those from normal donors, sera from ovarian cancer patients contain significantly higher levels of annexin A3. Furthermore, serum levels of annexin A3 were significantly higher in platinum-resistant patients than in platinum-sensitive patients. To gain insight into the mechanism of secretion, the ovarian cancer cell lines were examined using both transmission electron microscopy and immunoelectron microscopy. Compared with parent cells, there are significantly more vesicles in the cytoplasm of ovarian cancer cells that express high levels of annexin A3, and at least some vesicles are annexin A3-positive. Moreover, some vesicles appear to be fused with the cell membrane, suggesting that annexin A3 secretion may be associated with exocytosis and the release of exosomes. This is supported by our observation that ovarian cancer cells expressing higher levels of annexin A3 released increased numbers of exosomes. Furthermore, annexin A3 can be detected in exosomes released from cisplatin-resistant cells (SKOV3/Cis) by immunoblotting and immunoelectron microscopy.     

生物体内多胺对蛋白质影响的研究进展

多胺是普遍存在于生物体中的一种脂肪族阳离子胺。多胺通过离子键和氢键的形式与生物大分子结合,调节生物大分子的生物学活性,调控细胞的生长和发育。多胺对核酸的作用一直是关注热点,而针对蛋白质的影响目前研究较少。本文主要针对多胺调控代谢相关酶、通道蛋白质和其他功能性蛋白质以及相关规律和机制进行综述,并从蛋白质结构和功能角度探讨了多胺与蛋白质之间的相互作用关系,同时总结了多胺与蛋白质相互作用研究在疾病治疗中的应用前景和面临的问题。     

Mitochondrial comparative proteomics of human ovarian cancer cells and their platinum-resistant sublines

Resistance to platinum-based chemotherapy is the major obstacle to successful treatment of ovarian cancer. It is evident that mitochondrial defects and the dysfunctions of oxidative phosphorylation and energy production in ovarian cancer cells were directly related to their resistance to platinum drugs. Using 2-D DIGE, we compared mitochondrial proteins from two platinum-sensitive human ovarian cancer cell lines (SKOV3 and A2780) with that of four platinum-resistant sublines (SKOV3/CDDP, SKOV3/CBP, A2780/CDDP, and A2780/CBP). Among the 236 differentially expressed spots, five mitochondrial proteins (ATP-α, PRDX3, PHB, ETF, and ALDH) that participate in the electron transport respiratory chain were identified through mass spectrometry. All of them are downregulated in one or two of the platinum-resistant cell lines. Three proteins (ATP-α, PRDX3, and PHB) were validated by using western blot and immunohistochemistry. There is a significant decrease of PHB in tumor tissues from ovarian cancer patients who were resistant to platinum-based chemotherapies. This is the first direct mitochondrial proteomic comparison between platinum-sensitive and resistant ovarian cancer cells. These studies demonstrated that 2-D DIGE-based proteomic analysis could be a powerful tool to investigate limited mitochondrial proteins, and the association of PHB expression with platinum resistance indicates that mitochondria defects may contribute to platinum resistance in ovarian cancer cells.     

台湾生物多样性资料整合之经验与策略

台湾生物多样性数据库之整合从2001年开始, 是因为数位典藏计划、生物多样性推动方案, 及台湾加入全球生物多样性信息网络(Global Biodiversity Information Facility, GBIF), 均在这一年启动。2002年“中研院”开始建置台湾物种名录数据库(TaiBNET), GBIF之台湾入口网TaiBIF则是在2004年时建置, 用来整合台湾生物多样性的资料并与国际接轨。所采用之方法及格式均依循GBIF所发展的交换标准, 一来可以整合台湾的数据, 二来可及时与国际交换数据。虽然TaiBNET及TaiBIF已突破智慧财产权(知识产权)的障碍, 可搜集整合数位典藏各子计划逐年累积的资料, 但跨部门间及非数位典藏计划所产生的数据, 仍因各单位及个人的本位主义而难以整合分享, 特别是生态分布原始数据。因此2008年在“中研院”成立了跨主管部门的委员会, 制订可行之资料搜集、整合与公开的政策, 并要求各主管部门在委办合约中纳入。无人否认数据库整合的重要, 但在现行对研究人员考评制度下, 研究人员大多不愿投入数据库建置的学术服务工作, 所获得的人力与经费亦日益短缺而难以永续经营。亟需相关部门的重视与支持。TaiBIF在过去6年来的推动成果虽未臻理想, 但所获的经验和心得仍有可供外界参考与借镜之处。