MicroRNAs （miRNAs） are a class of naturally occurring small non-coding RNAs that target protein-coding mRNAs at the post-transcriptional level. Our previous studies suggest that mir-21 functions as an oncogene and h...MicroRNAs （miRNAs） are a class of naturally occurring small non-coding RNAs that target protein-coding mRNAs at the post-transcriptional level. Our previous studies suggest that mir-21 functions as an oncogene and has a role in tumorigenesis, in part through regulation of the tumor suppressor gene tropomyosin 1 （TPM1）. Given that TPM1 has been implicated in cell migration, in this study we further investigated the role of mir-21 in cell invasion and tumor metastasis. We found that suppression of mir-21 in metastatic breast cancer MDA-MB-231 cells significantly reduced invasion and lung metastasis. Consistent with this, ectopic expression of TPM1 remarkably reduced cell invasion. Furthermore, we identified two additional direct mir-21 targets, programmed cell death 4 （PDCD4） and maspin, both of which have been implicated in invasion and metastasis. Like TPM1, PDCD4 and maspin also reduced invasiveness of MDA-MB-231 cells. Finally, the expression of PDCD4 and maspin inversely correlated with mir-21 expression in human breast tumor specimens, indicating the potential regulation of PDCD4 and maspin by mir-21 in these tumors. Taken together, the results suggest that, as an oncogenic miRNA, mir-21 has a role not only in tumor growth but also in invasion and tumor metastasis by targeting multiple tumor/metastasis suppressor genes. Therefore, suppression of mir-21 may provide a novel approach for the treatment of advanced cancers.展开更多
将牛分枝杆菌哺乳动物细胞侵入蛋白4A(Mammalian cell-entry protein 4A,Mce4A)基因克隆至原核表达载体pET30a(+)中,得到重组表达载体pET30-mce4A,转入宿主菌BL21(DE3)中,获得大量表达,表达量占菌体蛋白总量的52%,大小约为43 Ku。经Ni-...将牛分枝杆菌哺乳动物细胞侵入蛋白4A(Mammalian cell-entry protein 4A,Mce4A)基因克隆至原核表达载体pET30a(+)中,得到重组表达载体pET30-mce4A,转入宿主菌BL21(DE3)中,获得大量表达,表达量占菌体蛋白总量的52%,大小约为43 Ku。经Ni-NTA琼脂糖亲和层析获得Mce4A重组蛋白;圆二色谱(CD)测定结果表明,Mce4A重组蛋白α螺旋含量为31.1%,β-折叠含量为0%,无规卷曲含量为61.0%,转角含量为7.9%。为进一步开展牛分枝杆菌致病机理的研究和寻找新的药物作用靶位点奠定了基础。展开更多
文摘MicroRNAs （miRNAs） are a class of naturally occurring small non-coding RNAs that target protein-coding mRNAs at the post-transcriptional level. Our previous studies suggest that mir-21 functions as an oncogene and has a role in tumorigenesis, in part through regulation of the tumor suppressor gene tropomyosin 1 （TPM1）. Given that TPM1 has been implicated in cell migration, in this study we further investigated the role of mir-21 in cell invasion and tumor metastasis. We found that suppression of mir-21 in metastatic breast cancer MDA-MB-231 cells significantly reduced invasion and lung metastasis. Consistent with this, ectopic expression of TPM1 remarkably reduced cell invasion. Furthermore, we identified two additional direct mir-21 targets, programmed cell death 4 （PDCD4） and maspin, both of which have been implicated in invasion and metastasis. Like TPM1, PDCD4 and maspin also reduced invasiveness of MDA-MB-231 cells. Finally, the expression of PDCD4 and maspin inversely correlated with mir-21 expression in human breast tumor specimens, indicating the potential regulation of PDCD4 and maspin by mir-21 in these tumors. Taken together, the results suggest that, as an oncogenic miRNA, mir-21 has a role not only in tumor growth but also in invasion and tumor metastasis by targeting multiple tumor/metastasis suppressor genes. Therefore, suppression of mir-21 may provide a novel approach for the treatment of advanced cancers.
文摘将牛分枝杆菌哺乳动物细胞侵入蛋白4A(Mammalian cell-entry protein 4A,Mce4A)基因克隆至原核表达载体pET30a(+)中,得到重组表达载体pET30-mce4A,转入宿主菌BL21(DE3)中,获得大量表达,表达量占菌体蛋白总量的52%,大小约为43 Ku。经Ni-NTA琼脂糖亲和层析获得Mce4A重组蛋白;圆二色谱(CD)测定结果表明,Mce4A重组蛋白α螺旋含量为31.1%,β-折叠含量为0%,无规卷曲含量为61.0%,转角含量为7.9%。为进一步开展牛分枝杆菌致病机理的研究和寻找新的药物作用靶位点奠定了基础。
