MicroRNAs （miRNAs）, which are small noncoding RNA molecules, play important roles in the post-transcriptional regulation process. The microRNA-21 gene （miR-21） has been reported to be highly expressed in various s...MicroRNAs （miRNAs）, which are small noncoding RNA molecules, play important roles in the post-transcriptional regulation process. The microRNA-21 gene （miR-21） has been reported to be highly expressed in various solid tumors, including breast cancer. Bone morphogenetic protein-6 （BMP-6） has been identified as an inhibitor of breast cancer epithelial-mesenchymal transition （EMT） through rescuing E-cadherin expression. We initiated experi- ments to identify the relationships between miR-21 and BMP-6 in breast cancer progression. Real-time PCR analysis showed that miR-21 expression was very high in MDA-MB-231 cells that expressed little BMP-6. A reverse correla- tion between BMP-6 and miR-21 was also determined in breast cancer tissue samples. Moreover, BMP-6 inhibited miR-21 transcription in MDA-MB-231 cells. In order to investigate how BMP-6 inhibited the miR-21 promoter （miPPR-21）, we constructed a series of miPPR-21 reporters. Luciferase assay results indicated that BMP-6 inhibited miPPR-21 activity through the E2-box and AP-l-binding sites. We also demonstrated that both δEF1 and TPA in- duced miR-21 expression. Using site-directed mutation and CHIP assay, we found that δEF1 induced miPPR-21 ac- tivity by binding to the E2-box on miPPR-21. Moreover, TPA triggered miPPR-21 activity through the AP-I binding sites. BMP-6 treatment significantly reduced the binding of these factors to miPPR-21 by decreasing the expression of δEF1 and c-Fos/c-Jun. We also demonstrated that BMP-6-induced downregulation of miR-21 modified the activ- ity of PDCD4 3＇UTR and inhibited MDA-MB-231 cell invasion. δEF1 overexpression and TPA induction blocked this inhibitory effect of BMP-6. In conclusion, BMP-6-induced inhibition of miR-21 suggests that BMP-6 may function as an anti-metastasis factor by a mechanism involving transcriptional repression of miR-21 in breast cancer.展开更多
目的:观察亮氨酸拉链EF-hand结构域跨膜蛋白1(leucine zipper/EF-hand-containing transmembrane protein 1,LETM1)在结肠癌中的表达情况,探讨LETM1蛋白是否能够成为判断结肠癌患者预后的新的生物学指标.方法:利用免疫组织化学法检测73...目的:观察亮氨酸拉链EF-hand结构域跨膜蛋白1(leucine zipper/EF-hand-containing transmembrane protein 1,LETM1)在结肠癌中的表达情况,探讨LETM1蛋白是否能够成为判断结肠癌患者预后的新的生物学指标.方法:利用免疫组织化学法检测73例结肠癌患者组织中LETM1蛋白的表达水平和蛋白激酶B(protein kinase B,PKB)/Akt的丝氨酸473(Ser473)、苏氨酸308(Thr308)两个磷酸化位点及葡萄糖合成激酶3β(glycogen synthase k i n a s e 3β,G S K3β)的磷酸化水平,并根据LETM1蛋白表达水平进行高表达和低表达分组;采用Kaplan-Meier法分析各组无疾病生存期;采用χ2检验进行组间单因素分析.结果:在结肠癌患者中LETM1蛋白高表达率为54.8%,LETM1蛋白在结肠癌浸润深度、分化及淋巴结转移中低表达和高表达率分别为27.3%/72.7%、38.3%/61.7%和22.7%/77.3%,其差异均有统计学意义(P<0.05),而与年龄、性别、肿瘤大小未见统计学意义(P>0.05).LETM1蛋白在结肠癌组织中可以激活磷脂酰肌醇3激酶(phosphatidylinositol 3 kinase,PI-3K)/A k t信号传导通路.L ETM1高表达患者无疾病生存期显著低于LETM1低表达患者(P<0.05).结论:LETM1蛋白在结肠癌中高表达,可能参与结肠癌的发生、发展与复发.LETM1蛋白可以作为预测结肠癌患者预后的新的生物学指标.展开更多
文摘MicroRNAs （miRNAs）, which are small noncoding RNA molecules, play important roles in the post-transcriptional regulation process. The microRNA-21 gene （miR-21） has been reported to be highly expressed in various solid tumors, including breast cancer. Bone morphogenetic protein-6 （BMP-6） has been identified as an inhibitor of breast cancer epithelial-mesenchymal transition （EMT） through rescuing E-cadherin expression. We initiated experi- ments to identify the relationships between miR-21 and BMP-6 in breast cancer progression. Real-time PCR analysis showed that miR-21 expression was very high in MDA-MB-231 cells that expressed little BMP-6. A reverse correla- tion between BMP-6 and miR-21 was also determined in breast cancer tissue samples. Moreover, BMP-6 inhibited miR-21 transcription in MDA-MB-231 cells. In order to investigate how BMP-6 inhibited the miR-21 promoter （miPPR-21）, we constructed a series of miPPR-21 reporters. Luciferase assay results indicated that BMP-6 inhibited miPPR-21 activity through the E2-box and AP-l-binding sites. We also demonstrated that both δEF1 and TPA in- duced miR-21 expression. Using site-directed mutation and CHIP assay, we found that δEF1 induced miPPR-21 ac- tivity by binding to the E2-box on miPPR-21. Moreover, TPA triggered miPPR-21 activity through the AP-I binding sites. BMP-6 treatment significantly reduced the binding of these factors to miPPR-21 by decreasing the expression of δEF1 and c-Fos/c-Jun. We also demonstrated that BMP-6-induced downregulation of miR-21 modified the activ- ity of PDCD4 3＇UTR and inhibited MDA-MB-231 cell invasion. δEF1 overexpression and TPA induction blocked this inhibitory effect of BMP-6. In conclusion, BMP-6-induced inhibition of miR-21 suggests that BMP-6 may function as an anti-metastasis factor by a mechanism involving transcriptional repression of miR-21 in breast cancer.
文摘目的:观察亮氨酸拉链EF-hand结构域跨膜蛋白1(leucine zipper/EF-hand-containing transmembrane protein 1,LETM1)在结肠癌中的表达情况,探讨LETM1蛋白是否能够成为判断结肠癌患者预后的新的生物学指标.方法:利用免疫组织化学法检测73例结肠癌患者组织中LETM1蛋白的表达水平和蛋白激酶B(protein kinase B,PKB)/Akt的丝氨酸473(Ser473)、苏氨酸308(Thr308)两个磷酸化位点及葡萄糖合成激酶3β(glycogen synthase k i n a s e 3β,G S K3β)的磷酸化水平,并根据LETM1蛋白表达水平进行高表达和低表达分组;采用Kaplan-Meier法分析各组无疾病生存期;采用χ2检验进行组间单因素分析.结果:在结肠癌患者中LETM1蛋白高表达率为54.8%,LETM1蛋白在结肠癌浸润深度、分化及淋巴结转移中低表达和高表达率分别为27.3%/72.7%、38.3%/61.7%和22.7%/77.3%,其差异均有统计学意义(P<0.05),而与年龄、性别、肿瘤大小未见统计学意义(P>0.05).LETM1蛋白在结肠癌组织中可以激活磷脂酰肌醇3激酶(phosphatidylinositol 3 kinase,PI-3K)/A k t信号传导通路.L ETM1高表达患者无疾病生存期显著低于LETM1低表达患者(P<0.05).结论:LETM1蛋白在结肠癌中高表达,可能参与结肠癌的发生、发展与复发.LETM1蛋白可以作为预测结肠癌患者预后的新的生物学指标.
