国家高技术(863)计划资助项目(2001AA217101),国家杰出青年科学基金(39925036)和军队杰出青年科学基金(98J009)资助项目.
This work was supported by grants from State 863 High Technology R&D Project of China (2001AA217101), National Outstanding Youth Scientific Fund (39925036) and Outstanding Youth Scientific Fund of PLA (98J009).
通过稳定转染人宫颈癌HeLa细胞,建立了野生型caspase-3(wt-casp3),大小亚基序列颠倒的重组caspase-3 (r-casp3),和N端融合绿脓杆菌外毒素(PE)转膜肽段的嵌合重组caspase-3 (cr-casp3)的诱导表达细胞系.蜕皮素诱导后细胞中检测到目的基因的表达,MTT检测和细胞计数结果表明,r-casp3和cr-casp3诱导表达后有效地导致HeLa细胞死亡,通过测定细胞中caspase-3活性,以及细胞周期检测、DNA梯状电泳条带检测(DNA ladder)、电镜观察等证实r-casp3和cr-casp3诱导表达后细胞发生了凋亡,且二者的促凋亡活性相当,而wt-casp3诱导表达细胞并未出现上述效应.结果表明,与野生型caspase-3活化需要上游分子的切割不同,重组caspase-3具有自发的促凋亡活性,而N端PE肽段的融合不影响这种活性,因此PE转膜结构域和重组caspase-3有望参与构建能转膜进入细胞内部,并杀伤细胞的新型肿瘤治疗分子.
Human cervix HeLa cells were stably transfected to establish cell lines that inducibly expressed 3 types of caspase-3 constructs, respectively. These constructs involved wild-type caspase-3 (wt-casp3), recombinant caspase-3 (r-casp3) in which the order of the small and large subunits was reversed in contrast to the original protein, and chimeric recombinant (cr-casp3) in which a Pseudomonas exotoxin A (PE)-derived peptide was fused to N-terminus of r-casp3. The expression of the interest genes was detected upon induction with ponasterone. The genes of r-casp3 and cr-casp3 were demonstrated to effectively cause cell death by MTT assay and cell counting. Cells that expressed r-casp3 or cr-casp3, but not wt-casp3, underwent apoptosis in a comparable level as determined by cell cycle analysis, genomic DNA ladders, and electronic microscopy. These results prove that unlike wild-type caspase-3 which is inactive unless proteolytically processed by upstream caspase, both recombinant caspase-3s are naturally active, and the N-terminal fusion of PE translocation domain does not interfere with the natural caspase-3 activity, suggesting their applications on the construction of novel tumor therapeutics that efficiently translocate to the cytosol of tumor cells and cause cell death.
贾林涛,张立红,于翠娟,纪宗玲,曹云新,王成济,杨安钢.嵌合重组caspase-3诱导表达促进肿瘤细胞凋亡[J].生物化学与生物物理进展,2003,30(2):272-277
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