Department of Molecular Medicine & Pathology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
Cancer Cell Int. 2010 Oct 1;10:36. doi: 10.1186/1475-2867-10-36.
Survivin is a member of the inhibitor-of-apoptosis (IAP) family which is widely expressed by many different cancers. Overexpression of survivin is associated with drug resistance in cancer cells, and reduced patient survival after chemotherapy and radiotherapy. Agents that antagonize the function of survivin hold promise for treating many forms of cancer. The purpose of this study was to investigate whether a cell-permeable dominant-negative survivin protein would demonstrate bioactivity against prostate and cervical cancer cells grown in three dimensional culture.
A dominant-negative survivin (C84A) protein fused to the cell penetrating peptide poly-arginine (R9) was expressed in E. coli and purified by affinity chromatography. Western blot analysis revealed that dNSurR9-C84A penetrated into 3D-cultured HeLa and DU145 cancer cells, and a cell viability assay revealed it induced cancer cell death. It increased the activities of caspase-9 and caspase-3, and rendered DU145 cells sensitive to TNF-α via by a mechanism involving activation of caspase-8.
The results demonstrate that antagonism of survivin function triggers the apoptosis of prostate and cervical cancer cells grown in 3D culture. It renders cancer cells sensitive to the proapoptotic affects of TNF-α, suggesting that survivin blocks the extrinsic pathway of apoptosis. Combination of the biologically active dNSurR9-C84A protein or other survivin antagonists with TNF-α therapy warrants consideration as an approach to cancer therapy.
Survivin 是凋亡抑制因子（IAP）家族的一员，在许多不同的癌症中广泛表达。Survivin 的过表达与癌细胞的耐药性有关，并与化疗和放疗后患者的生存率降低有关。拮抗 survivin 功能的药物有望治疗多种形式的癌症。本研究旨在探讨穿透细胞的显性负性 survivin 蛋白是否对三维培养的前列腺癌和宫颈癌细胞具有生物活性。
与穿透肽多聚精氨酸（R9）融合的显性负性 survivin（C84A）蛋白在大肠杆菌中表达，并通过亲和层析进行纯化。Western blot 分析显示 dNSurR9-C84A 穿透到 3D 培养的 HeLa 和 DU145 癌细胞中，细胞活力测定显示它诱导癌细胞死亡。它增加了 caspase-9 和 caspase-3 的活性，并通过涉及 caspase-8 激活的机制使 DU145 细胞对 TNF-α敏感。
结果表明，拮抗 survivin 功能可触发三维培养的前列腺癌和宫颈癌细胞的凋亡。它使癌细胞对 TNF-α的促凋亡作用敏感，表明 survivin 阻断了细胞凋亡的外在途径。将具有生物活性的 dNSurR9-C84A 蛋白或其他 survivin 拮抗剂与 TNF-α治疗联合使用，值得考虑作为癌症治疗的一种方法。
