Objective To investigate the effects of anti-HPV16E6-ribozyme (HRz) on phenotype and gene expression of a cervical cancer cell line.Methods HRz was designed by computer programs. HRz's activity was identified by cleavage experiments in vitro. HRz and empty eukaryotic plasmids were transfected into CaSKi cells with lipofectin, then renamed CaSKi-R and CaSKi-P, respectively. The expression of ribozyme in transfected cells was observed by RNA dot blot. The amounts of E6 mRNA in three kinds of cells lines were detected by Northern blot. Cell growth curves and soft agar forming ability were studied. The ability of each cell line to form tumors was assessed in nude mice. Apoptosis rates a nd expression of c-myc, bcl-2, p53 and Fas were detected by flow cytometry (FC M). Antigens of tumor cells, HLA-1, HLA-2, B7-1 and B7-2 were also detected. NK, LAK, and CD3AK cells were induced. Their cytotoxicities were detected in CaSKi-R, CaSKi-P, and CaSKi cells.Results In vitro cleavage reaction demonstrated that HRz could cleave HPV16E6 mRNA in a site-specific manner. HRz could be expressed stably in transfected CaSKi cells . Northern blot analysis showed that E6 mRNA levels were lower in CaSKi-R than in CaSKi. The growth rate of CaSKi-R was slower than those of CaSKi and CaSKi-P. The soft agar-forming rate of CaSKi-R was lower compared with those of C aSKi and CaSKi-P cells. The ability of CaSKi-R to form tumors in nude mice wa s also poor. The apoptosis rate of CaSKi-R cells was much higher than those of CaSKi and CaSKi-P. HRz could reduce the expression of E6, c-myc and bcl-2 p roteins, and increase the expression of p53 as well. HRz could increase the expression of HLA-2, B7-1 and B7-2 antigens. The cytotoxicity of NK, LAK and CD 3AK cells was much higher in CaSKi-R than in CaSKi-P and CaSKi cells. Conclusion HRz not only reverses the malignant phenotype of CaSKi cells partially, but also induces apoptosis in the cells, and increases sensitivity of CaSKi cells to imm une cells.%目的研究特异性抗HPV16E6核酶对宫颈癌细胞表型和基因表达的影响.方法应用计算机软件设计抗HPV16E6核酶,并以体外切割实验验证其效率.以脂质体法将抗HPV16 E6核酶、空载体质粒分别导入CaSKi细胞,命名为CaSKi-R、CaSKi-P细胞.点杂交检测核酶在细胞中的表达,Northern杂交检测细胞中E6基因的表达.测定三种细胞的生长曲线和软琼脂克隆形成率,检测其在裸鼠体内的成瘤能力.流式细胞仪检测三种细胞的凋亡率,并测定c-myc、bcl-2、p53、fas蛋白的表达.检测三种细胞表面抗原的表达,包括HLA-1、HL A-2、B7-1、B7-2.诱导NK、LAK、CD3AK细胞,测定它们对三种宫颈癌细胞的杀伤作用. 结果体外切割实验证实抗HPV16E6核酶能特异性切割靶基因,点杂交证明核酶能在CaSKi-R细胞中稳定表达,Northern杂交显示CaSKi-R中表达E6较CaSKi-P、CaSKi明显降低.与CaSKi细胞相比,CaSKi-R细胞生长速度、软琼脂克隆形成率明显降低,在裸鼠体内的成瘤性降低, 凋亡率明显增高.而CaSKi-P细胞无此改变.核酶的导入使CaSKi-R细胞表达HPV16E6、c- myc、bcl-2蛋白明显减少,而表达p53明显增高.CaSKi-R细胞中HLA-2、B7-1、B7-2抗原表达增高.NK、LAK、CD3AK细胞对CaSKi-R的杀伤作用明显高于对CaSKi细胞.结论抗HPV16E6核酶不但能部分逆转宫颈癌CaSKi细胞的恶性表型,而且能诱导CaSKi细胞凋亡, 提高其对免疫细胞的敏感性.
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