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
Endometrial cancer （EC） is the most common and lethal gynaecological cancer type in Europe and in North America. Frequently EC arises more in the corpus proper and manifests as round, polypoid expansile masses, but ...Endometrial cancer （EC） is the most common and lethal gynaecological cancer type in Europe and in North America. Frequently EC arises more in the corpus proper and manifests as round, polypoid expansile masses, but it may also originate in the lower uterine segment or spread in endometrium with necrosis and hemorrhage. The analysis was performed using a custom panel containing all DNA sequences loci coding pre-miRNAs and genes related to biogenesis and regulation of sncRNAs in normal and tumor tissues extracted from 6 unrelated patients with endometrial carcinoma. The identified variations were correlated with mature miRNAs differentially expressed in the same normal and tumor endometrial tissues. The comparison analysis confirmed the high degree of cellular and genetic intratumoral heterogeneity with a temporal and spatial miRNA expression distribution in association with genomic variants identified. The classification of specific DNA mutations, onto the loci identified, should be suitable to characterize possible instability genome regions and help classification of tumors to ameliorate the clinical management of patients affected by endometrial carcinoma.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Endometrial cancer （EC） is the most common and lethal gynaecological cancer type in Europe and in North America. Frequently EC arises more in the corpus proper and manifests as round, polypoid expansile masses, but it may also originate in the lower uterine segment or spread in endometrium with necrosis and hemorrhage. The analysis was performed using a custom panel containing all DNA sequences loci coding pre-miRNAs and genes related to biogenesis and regulation of sncRNAs in normal and tumor tissues extracted from 6 unrelated patients with endometrial carcinoma. The identified variations were correlated with mature miRNAs differentially expressed in the same normal and tumor endometrial tissues. The comparison analysis confirmed the high degree of cellular and genetic intratumoral heterogeneity with a temporal and spatial miRNA expression distribution in association with genomic variants identified. The classification of specific DNA mutations, onto the loci identified, should be suitable to characterize possible instability genome regions and help classification of tumors to ameliorate the clinical management of patients affected by endometrial carcinoma.
