人骨骼肌肌钙蛋白C在大肠杆菌中的表达及其抗肿瘤作用

为了探索重组人骨骼肌型肌钙蛋白C(rhTnC)的抗肿瘤作用,采用PCR技术,从人乳腺cDNA文库中获得编码TnC的cDNA序列,在大肠杆菌中进行了表达.经镍柱亲和层析纯化后,分别检测其在体外对人脐静脉内皮细胞生长的抑制作用与对小鼠异位移植肿瘤(S-180)生长的抑制作用.结果表明,rhTnC在大肠杆菌中呈可溶性表达.分离纯化后的rhTnC在体外对人脐静脉内皮细胞生长呈剂量依赖性抑制(IC50为7.5μg/ml);对小鼠异位移植肿瘤的生长也有明显的抑制作用,在20mg/(kg·d)剂量下对S-180的抑制率为64.4%.以上结果说明,rhTnC可抑制血管内皮细胞生长,并具有抗肿瘤作用.

Human TnC Expressed in E.coli and Its Effect on Anti-tumor

Troponin C(TnC) is a Ca 2+-binding protein that in a complex with troponin I and troponin T on the actin-tropomyosin thin filament is required for Ca 2+-dependent regulation of striated muscle contraction. Since troponin I has been proved to have anti-angiogenesis effect on tumor growth,the anticancer effect of recombinant human troponin C (rhTnC) was explored.An expression plasmid vector pLysS/pET3b-TnC was constructed,following transfection into E.coli. SDS-PAGE analysis showed that the expression protein was soluble and displayed single band of native TnC (18 kD) after purified by Ni-affinity chromatogramphy.Treatment of cultured human umbilical vein epithelial cell (HUV-EC) with recombinant TnC showed that rhTnC significantly suppressed HUV-EC proliferation in a dose-dependent manner (IC_ 50 =7^5 μg/ml).The inhibitory effect was also observed on mouse xenograft tumor,being effective at dose of 5 mg/kg,reaching maximal inhibition 64^4% at dose of 20 mg/kg. These data suggestd that rhTnC was capable of inhibiting endothelial cell-derived cancer proliferation and had the potenital as anti-tumor agent.