ABSTRACT: Expression of miR-200c in claudin-low breast cancer alters stem cell functionality, enhances chemosensitivity and reduces metastatic potential
Project description:Claudin-low tumors are a highly aggressive breast cancer subtype with no targeted treatments and a clinically documented resistance to chemotherapy. They are significantly enriched in cancer stem cells (CSCs), which makes claudin-low tumor models particularly attractive for studying CSC behavior and developing novel approaches to minimize CSC therapy resistance. One proposed mechanism by which CSCs arise is via an epithelial-mesenchymal transition (EMT), and reversal of this process may provide a potential therapeutic approach for increasing tumor chemosensitivity. Therefore, we investigated the role of the miR-200 family of microRNAs in regulating the epithelial state, stem-like properties, and therapeutic response in an in vivo primary, syngeneic p53null claudin-low tumor model that is normally deficient in miR-200 expression. Using an inducible lentiviral approach, we expressed the miR-200c cluster in this claudin-low model and found that it changed the epithelial state, and consequently, impeded CSC behavior in these mesenchymal tumors. Moreover, these state changes were accompanied by a decrease in proliferation and an increase in the differentiation status. MiR-200c expression also forced a significant reorganization of tumor architecture, affecting important cellular processes involved in cell-cell contact, cell adhesion, and motility. Accordingly, induced miR200c expression also significantly enhanced the chemosensitivity and decreased the metastatic potential of this p53null claudin-low tumor model. Collectively, our data suggest that miR-200c expression in claudin-low tumors offers a potential therapeutic application to disrupt the EMT program on multiple fronts in this mesenchymal tumor subtype, by altering tumor growth, chemosensitivity, and metastatic potential in vivo. reference x sample
Project description:Claudin-low tumors are a highly aggressive breast cancer subtype with no targeted treatments and a clinically documented resistance to chemotherapy. They are significantly enriched in cancer stem cells (CSCs), which makes claudin-low tumor models particularly attractive for studying CSC behavior and developing novel approaches to minimize CSC therapy resistance. One proposed mechanism by which CSCs arise is via an epithelial-mesenchymal transition (EMT), and reversal of this process may provide a potential therapeutic approach for increasing tumor chemosensitivity. Therefore, we investigated the role of the miR-200 family of microRNAs in regulating the epithelial state, stem-like properties, and therapeutic response in an in vivo primary, syngeneic p53null claudin-low tumor model that is normally deficient in miR-200 expression. Using an inducible lentiviral approach, we expressed the miR-200c cluster in this claudin-low model and found that it changed the epithelial state, and consequently, impeded CSC behavior in these mesenchymal tumors. Moreover, these state changes were accompanied by a decrease in proliferation and an increase in the differentiation status. MiR-200c expression also forced a significant reorganization of tumor architecture, affecting important cellular processes involved in cell-cell contact, cell adhesion, and motility. Accordingly, induced miR200c expression also significantly enhanced the chemosensitivity and decreased the metastatic potential of this p53null claudin-low tumor model. Collectively, our data suggest that miR-200c expression in claudin-low tumors offers a potential therapeutic application to disrupt the EMT program on multiple fronts in this mesenchymal tumor subtype, by altering tumor growth, chemosensitivity, and metastatic potential in vivo.
Project description:Background: MicroRNAs are noncoding RNA molecules of ~22 nucleotides with diagnostic and therapeutic action, affecting the expression of mRNAs involved in invasion, migration, and development. miR-200c is part of the miR-200c/141 cluster on chromosome 12p13. Its mechanism of action when encapsulated is critical in lung cancer when patients express changes in miRNAs. miR-200c be a potential biomarkers for various lung diseases. As a potential therapy, miR-200c can impact lives as target lung cancer is a leading cause of death with about 234,000 cases annually, high heterogeneity, complex screening, and a 5-year survival rate of 16%. Encapsulated miR-200c efficiently enhances bioavailability, pharmacokinetics of therapeutics and targeting to cells, improves efficacy and provides potential cure. Methods: The functions of miR-200c were determined in non-metastatic KW-634 and metastatic 821-T4 and 821-LN mouse lung cancer cell lines after various nano vehicle treatments. Viability and cytotoxicity were determined by cell cycle and quantitative real-time PCR analyses were used to quantify levels of miR-200c and its target genes. In situ hybridization was used to visualize patterns of expression of miR-200c and others in the lung and many organs. Next-generation sequencing, invasion and migration assays using transwell chambers, and ActivSignal were used to elucidate the activation and inhibition profiles and perform direct expression measurements and modification of cellular components.
Project description:The miR-200 family of microRNAs consisting of miR-141, miR-200a, miR-200b, miR-200c and miR-429 are key regulators of breast cancer progression. The miR200 family maintains mammary epithelial identity and downregulation of miR-200 expression drives the epithelial-to-mesenchymal transition. Re-expression of one or more miR-200 family members in tumor cells with mesenchymal characteristics may restore the epithelial phenotype and alter growth and metastatic potential. To test this, the miR-200b/200a/429 cluster was re-expressed in a murine claudin-low mammary tumor cell line, RJ423
Project description:Proteomic analysis of differentially expressed proteins in MDA-MB-231 and MCF-10A cell lines when miR-200c and miR-203 were transiently expressed or inhibited, respectively.
Project description:Macrophages constitute a major part of the tumor-infiltrating immune cells and within the tumor microenvironment acquire an alternatively activated, tumor-supporting phenotype. Factors released by tumor cells are crucial for the recruitment of tumor-associated macrophages. In the present project, we aimed to understand the role of miR-200c in the interplay between tumor cells and macrophages. To this end, we employed a coculture system of MCF7 breast tumor cells and primary human macrophages and observed a substantial transfer of miR-200c from apoptotic tumor cells to macrophages, which required intact CD36 receptor in macrophages. We further comprehensively determined miR-200c targets in macrophages by mRNA-sequencing and found numerous migration-associated mRNAs to be downregulated by miR-200c. Consequently, miR-200c attenuated macrophage infiltration into 3-dimensional tumor spheroids. The miR-200c-mediated reduction of infiltration further correlated well with a miR-200c migration signature comprised of four miR-200c-repressed targets (PPM1F, RAB11FIB2, RDX, MSN).
Project description:MircoRNAs are small RNAs which regulate a pleiotropy of cellular processes and are also involved in tumorigenesis, cancer progression and therapy resistance. We investigated the influence of miRNA-200c on chemoresistance of tumor cells. A proteomic approach identified glutathione S-transferases to be differentially expressed when miR-200c was knocked out and cells were treated with the chemotherapeutic drug doxorubicin.
Project description:The mouse incisor is a remarkable tooth that grows throughout the animal’s lifetime. This continuous renewal is fueled by epithelial stem cells that give rise to ameloblasts, which generate enamel, and little is known about the function of specific miRNAs in this process. Here we describe the role of a novel Pitx2:miR-200c/141:Noggin regulatory pathway in dental epithelial cell differentiation. miR-200c repressed noggin, an antagonist of Bmp signaling. Pitx2 expression caused an up-regulation of miR-200c and chromatin immunoprecipitation (ChIP) assays revealed endogenous Pitx2 binding to the miR-200c/141 promoter. A positive feedback loop was discovered between miR-200c and Bmp signaling. miR-200c/141 induced expression of E-cadherin and the dental epithelial cell differentiation marker, amelogenin. In addition, miR-203 expression was activated by endogenous Pitx2 and targeted the Bmp antagonist Bmper to further regulate Bmp signaling. miR-200c/141 knockout mice showed defects in enamel formation with decreased E-cadherin and amelogenin expression and increased noggin expression. Our in vivo and in vitro studies reveal a multistep transcriptional program involving the Pitx2:miR-200c/141:Noggin regulatory pathway that is important in epithelial cell differentiation and tooth development.