抗Ⅳ型胶原酶胞内抗体对人巨细胞肺癌PG细胞侵袭的抑制作用

目的探讨内质网滞留型胞内抗体对Ⅳ型胶原酶分泌及其对人巨细胞肺癌PG细胞侵袭的抑制作用。方法构建了编码胞浆和内质网滞留型抗Ⅳ型胶原酶抗体的表达载体pcDNA3．1-CP．scFv和pcDNA3．1-ER．scFv。对人巨细胞肺癌PG细胞系进行基因转染。以Western blot检测pcDNA3．1-CP．scFv和pcDNA3．1-ER．scFv的表达,明胶酶谱检测PG细胞Ⅳ型胶原酶分泌情况,Matrigel实验检测细胞侵袭。结果CP．scFv和ER．scFv胞内抗体在PG细胞内表达,ER．scFv对Ⅳ型胶原酶分泌具有显著的抑制作用,对基质金属蛋白酶-9和基质金属蛋白酶-2的抑制率分别为85．7％和51．2％;而CP．scFv对Ⅳ型胶原酶分泌无抑制作用。ER．scFv编码基因转染的PG细胞与野生型和空白质粒组比较,对体外侵袭有明显的抑制,抑制率为76．3％;而CP．scFv编码基因转染的PG细胞未显示出有抑制作用。结论内质网滞留型胞内抗体技术可以在蛋白加工、分泌通路中抑制Ⅳ型胶原酶的活性,进而抑制肿瘤侵袭,可能在肿瘤基因治疗中具有重要的应用前景。

Inhibitory effect of anti-type IV collagenase intrabody on invasiveness of human pulmonary giant cell carcinoma PG cells in vitro

OBJECTIVE: To explore the inhibitory effects of endoplasmic reticulum-retained intrabody on the secretion of type IV collagenase and the invasion of human pulmonary giant cell carcinoma PG cells in vitro. METHODS: Two expression plasmids were constructed, pcDNA3.1-CP.scFv and pcDNA3.1-ER.scFv encoding cytoplasm-retained and endoplasmic reticulum-retained single chain antibodies against the type IV collagenase, respectively. The intracellular antibody genes were transfected into the human pulmonary giant cell carcinoma PG cells. Western blot was performed to detect the expression of pcDNA3.1-CP.scFv and pcDNA3.1-ER.scFv. Gelatin zymography was performed to detect seretion of type IV collagenase in PG cells and Matrigel assay was employed for determination of the cell invasiveness. RESULTS: Both of cytoplasm-retained and endoplasmic reticulum-retained introbodies, CP.scFv and ER.scFv, were expressed in PG cells. ER.scFv, significantly inhibited the secretion of type IV collegenase. As shown, matrix metalloproteinase 9 and matrix metalloproteinase 2 were inhibited by 85.7% and by 51.2%, respectively. However, CP.scFv did not show such inhibitory effect. The ER.scFv encoding gene-transfected PG cells were much less invasive than parental or vector control cells, the inhibition rate was 76.3% (P < 0.05), whereas CP.scFv encoding gene-transfected PG cells showed no reduction in invasiveness. CONCLUSION: Those findings demonstrate that endoplasmic reticulum (ER)-retained intracellular antibody technology may selectively abrogate the activity of type IV collagenase in the protein trafficking and secretory pathway and effectively inhibit tumor cell invasion in vitro. Anti-type IV collagenase intrabody may be further used in cancer gene therapy.