Project description:To determine miRNAs regulated by TTF-1 in SCLC cell lines, miRNA array analyses were carried out in NCI-H209 cells following TTF-1 knockdown
Project description:To investigate genes possibly regulated by TTF-1 in small cell lung cancer cell lines, we compared gene expression profiles of NCI-H209 and Lu139 cell lines electroporated with control and TTF-1 siRNAs.
Project description:Thyroid transcription factor-1 (TTF-1), also known as NKX2-1, plays a role as a lineage-survival oncogene in lung adenocarcinoma with double-edged sword characteristics. Although previous studies steadily accumulated evidence for roles of TTF-1 in the transcriptional regulation of protein-coding genes, very little is known about its regulatory relationship with miRNAs. In this study, we have identified miR-532-5p as a novel transcriptional target of TTF-1 by an integrative approach, which was designed to extract maximal information from expression profiles of both patient tumors in vivo and TTF-1-inducible cell lines in vitro. Consequently, we have found that miR-532-5p is directly regulated by TTF-1 through its binding to a genomic region 8 kb upstream of miR-532-5p, which appeared to impose transcriptional regulation independent of that of CLCN5, a protein-coding gene harboring miR-532-5p in its intron 3. Further, we have also identified KRAS and MKL2 as novel direct targets of miR-532-5p. Introduction of miR-532-5p mimics markedly induced apoptosis in KRAS-mutant as well as KRAS wildtype lung adenocarcinoma cell lines. Interestingly, miR-532-5p affected the MEK-ERK pathway signaling specifically in cell lines sensitive to siKRAS treatment, while the miR-532-5p-mediated effects were clearly phenocopied by repressing expression or inhibiting function of MKL2 regardless of KRAS mutation status. In summary, our findings demonstrate that miR-532-5p is as novel transcriptional target of TTF-1 and plays a tumor suppressive role by targeting KRAS and MKL2 in lung adenocarcinoma. Novel therapeutic strategies using miR-532-5p or an MKL2 inhibitor may prove effective against this hard-to-cure cancer irrespective of the dependence on KRAS-mediated signaling.
Project description:Although Thyroid transcription factor-1 (TTF-1, encoded by NKX2-1 gene) is highly expressed in small cell lung carcinoma (SCLC) and lung adenocarcinoma (LADC), difference in the functional roles of TTF-1 between SCLC and LADC remains to be elucidated. The aim of this study was to clarify the differences in the TTF-1 binding regions and functional roles in SCLC and LADC. Employing chromatin immunoprecipitation-sequencing (ChIP-seq) , here we compared the genome-wide TTF-1-binding profiles and the TTF-1-mediated transcriptional programs in a SCLC and a LADC cell lines. We also investigated ASCL1 binding regions in SCLC cells.
Project description:Thyroid transcription factor-1 (TTF-1), also known as NKX2-1, plays a role as a lineage-survival oncogene in lung adenocarcinoma with double-edged sword characteristics. Although previous studies steadily accumulated evidence for roles of TTF-1 in the transcriptional regulation of protein-coding genes, very little is known about its regulatory relationship with miRNAs. In this study, we have identified miR-532-5p as a novel transcriptional target of TTF-1 by an integrative approach, which was designed to extract maximal information from expression profiles of both patient tumors in vivo and TTF-1-inducible cell lines in vitro. Consequently, we have found that miR-532-5p is directly regulated by TTF-1 through its binding to a genomic region 8 kb upstream of miR-532-5p, which appeared to impose transcriptional regulation independent of that of CLCN5, a protein-coding gene harboring miR-532-5p in its intron 3. Further, we have also identified KRAS and MKL2 as novel direct targets of miR-532-5p. Introduction of miR-532-5p mimics markedly induced apoptosis in KRAS-mutant as well as KRAS wildtype lung adenocarcinoma cell lines. Interestingly, miR-532-5p affected the MEK-ERK pathway signaling specifically in cell lines sensitive to siKRAS treatment, while the miR-532-5p-mediated effects were clearly phenocopied by repressing expression or inhibiting function of MKL2 regardless of KRAS mutation status. In summary, our findings demonstrate that miR-532-5p is as novel transcriptional target of TTF-1 and plays a tumor suppressive role by targeting KRAS and MKL2 in lung adenocarcinoma. Novel therapeutic strategies using miR-532-5p or an MKL2 inhibitor may prove effective against this hard-to-cure cancer irrespective of the dependence on KRAS-mediated signaling.
Project description:Thyroid transcription factor-1 (TTF-1), also known as NKX2-1, plays a role as a lineage-survival oncogene in lung adenocarcinoma with double-edged sword characteristics. Although previous studies steadily accumulated evidence for roles of TTF-1 in the transcriptional regulation of protein-coding genes, very little is known about its regulatory relationship with miRNAs. In this study, we have identified miR-532-5p as a novel transcriptional target of TTF-1 by an integrative approach, which was designed to extract maximal information from expression profiles of both patient tumors in vivo and TTF-1-inducible cell lines in vitro. Consequently, we have found that miR-532-5p is directly regulated by TTF-1 through its binding to a genomic region 8 kb upstream of miR-532-5p, which appeared to impose transcriptional regulation independent of that of CLCN5, a protein-coding gene harboring miR-532-5p in its intron 3. Further, we have also identified KRAS and MKL2 as novel direct targets of miR-532-5p. Introduction of miR-532-5p mimics markedly induced apoptosis in KRAS-mutant as well as KRAS wildtype lung adenocarcinoma cell lines. Interestingly, miR-532-5p affected the MEK-ERK pathway signaling specifically in cell lines sensitive to siKRAS treatment, while the miR-532-5p-mediated effects were clearly phenocopied by repressing expression or inhibiting function of MKL2 regardless of KRAS mutation status. In summary, our findings demonstrate that miR-532-5p is as novel transcriptional target of TTF-1 and plays a tumor suppressive role by targeting KRAS and MKL2 in lung adenocarcinoma. Novel therapeutic strategies using miR-532-5p or an MKL2 inhibitor may prove effective against this hard-to-cure cancer irrespective of the dependence on KRAS-mediated signaling.
Project description:We evaluated the role of TTF-1/NKX2-1 on Smad3 and Smad4 binding in lung cancer cell lines. Smad3 binding sites in A549 cells and Smad3, Smad4, and TTF-1/NKX2-1 binding sites in H441 cells were determined by ChIP-seq.