Project description:P21-activated kinase 1 (Pak1) is a key oncogenic kinase and a lot of work about the mechanism of Pak1 action in cancer have been reported, while it remains unknown whether Pak1 could potentially regulate the biology of regulatory miRNAs by new interacting substrate. Here, we identified that Pak1 modulated the miR-132 expression in gastric cancer cells. Pak1 interacted with and phosphorylated activating transcription factor-2 (ATF2) on Serine 62 (Ser62), which blocked ATF2 translocation into cell nucleus. We further demonstrated that ATF2 induced miR-132 transcription via binding to the miR-132 promoter in the -30 to -39 region. Moreover, overexpression of miR-132 in gastric cancer cells significantly reduced cell adhesion, migration and invasion in vitro and hematogenous metastasis in vivo. MiR-132 targeted CD44 and fibronectin (FN) and promoted lymphocytes to gather around gastric cancer cells and kill them. More importantly, downregulation of miR-132 in gastric cancer was specifically associated with hematogenous metastasis, instead of lymph node or implantation metastasis. Taken together, miR-132 is a key negative regulator in the hematogenous metastasis of gastric cancer. A novel cell signaling pathway Pak1-ATF2-miR-132-CD44/FN is established and may be a new therapeutic target for hematogenous metastasis of gastric caner.
Project description:microRNA regulates cellular responses to ionizing radiation (IR) through the translational control of target genes. We analyzed time-series changes in microRNA expressions upon γ-irradiation in H1299 lung cancer cell lines using microarray. Significantly changed microRNAs were selected based on ANOVA analysis, target genes of which were enriched to MAPK signaling pathway. Concurrent analysis of mRNA and microRNA uncovered that the expression of miR-26b and its target ATF2 mRNA were inversely correlated in γ-irradiated H1299 cells. The overexpression of miR-26b induced the suppression of ATF2 in γ-irradiated cells. When we inhibit the MAPK signaling pathway using SP600125, JNK inhibitor, the expression of miR-26b was induced even in γ-irradiated H1299 cells. From these results, we concluded that the expression of miR-26b was coordinated regulated by MAPK signaling pathway upon ionizing radiation, and MAPK signaling pathway was regulated by miR-26b in turn. We analyzed the time-series miRNA profiles of radioresistant H1299 cells in response to 2 Gy of ionizing radiation (IR) by performing quadratic regression (QR) analysis to identify genes associated with radioresistance
Project description:Ovarian cancer has a clear predilection for metastasis to the omentum, but the underlying mechanisms involved in ovarian cancer spread are not well understood. Here, we used a parabiosis model that demonstrates preferential hematogenous metastasis of ovarian cancer to the omentum. Our studies revealed that the ErbB3-neuregulin1 (NRG1) axis is a dominant pathway responsible for hematogenous omental metastasis. Elevated levels of ErbB3 in ovarian cancer cells and NRG1 in the omentum allowed for tumor cell localization and growth in the omentum. Depletion of ErbB3 in ovarian cancer substantially impaired omental metastasis. Our results highlight hematogenous metastasis as a previously under-recognized mode of ovarian cancer metastasis. These findings have implications for designing new strategies aimed at preventing and treating ovarian cancer metastasis.
Project description:microRNA regulates cellular responses to ionizing radiation (IR) through the translational control of target genes. We analyzed time-series changes in microRNA expressions upon γ-irradiation in H1299 lung cancer cell lines using microarray. Significantly changed microRNAs were selected based on ANOVA analysis, target genes of which were enriched to MAPK signaling pathway. Concurrent analysis of mRNA and microRNA uncovered that the expression of miR-26b and its target ATF2 mRNA were inversely correlated in γ-irradiated H1299 cells. The overexpression of miR-26b induced the suppression of ATF2 in γ-irradiated cells. When we inhibit the MAPK signaling pathway using SP600125, JNK inhibitor, the expression of miR-26b was induced even in γ-irradiated H1299 cells. From these results, we concluded that the expression of miR-26b was coordinated regulated by MAPK signaling pathway upon ionizing radiation, and MAPK signaling pathway was regulated by miR-26b in turn.
Project description:MicroRNAs have emerged as key regulators of B cell fate decisions and immune function. Deregulation of several microRNAs in B cells leads to the development of autoimmune disease and cancer in mice. We demonstrate that the microRNA-212/132 cluster (miR-212/132) is induced in B cells in response to B cell receptor signaling. Enforced expression of miR-132 results in a block in early B cell development at the pre-pro-B cell to pro-B cell transition and induces apoptosis in primary bone marrow B cells. Importantly, loss of miR-212/132 results in increased B cell output under non-homeostatic conditions. We find that miR-212/132 regulates B lymphopoiesis by targeting the transcription factor SOX4. Co-expression of SOX4 with miR-132 rescues the defect in B cell development from over-expression of miR-132 alone. In addition, we show that the expression of miR-132 in cells that are prone to spontaneous B cell cancers can have a protective effect on cancer development. We have thus uncovered a novel regulator of B cell lineage specification that may potential applications in B cell cancer therapy RNA-seq of wild-type and microRNA-212/132 knock-out B-cells after IgM stimulation
Project description:The colonization of distant organs by metastatic carcinoma cells underpins most human cancer-related deaths, including those from head and neck squamous cell carcinoma (HNSCC). We report that miR-203, a miRNA that promotes keratinocyte differentiation, is necessary and sufficient to inhibit multiple post-extravasation events during HNSCC lung metastasis, including initial survival/engraftment, escape from metastatic dormancy, and overt colonization in vivo. Restoration of miR-203 expression in established lung metastases reduces overall metastatic burden. Instead of promoting differentiation, miR-203 controls lung metastasis through direct targeting of genes involved in cytoskeletal dynamics (LASP1), ECM remodeling (SPARC), and cell metabolism (NUAK1). Expression of miR-203 and its downstream targets correlates with HNSCC overall survival outcomes, suggesting the therapeutic potential of targeting this signaling axis. Total RNA (including small RNAs) was isolated from cultured cells stably infected in biological duplicate with either a scrambled control hairpin or miR-203. Samples were harvested in technical duplicate.
Project description:MicroRNAs have emerged as key regulators of B cell fate decisions and immune function. Deregulation of several microRNAs in B cells leads to the development of autoimmune disease and cancer in mice. We demonstrate that the microRNA-212/132 cluster (miR-212/132) is induced in B cells in response to B cell receptor signaling. Enforced expression of miR-132 results in a block in early B cell development at the pre-pro-B cell to pro-B cell transition and induces apoptosis in primary bone marrow B cells. Importantly, loss of miR-212/132 results in increased B cell output under non-homeostatic conditions. We find that miR-212/132 regulates B lymphopoiesis by targeting the transcription factor SOX4. Co-expression of SOX4 with miR-132 rescues the defect in B cell development from over-expression of miR-132 alone. In addition, we show that the expression of miR-132 in cells that are prone to spontaneous B cell cancers can have a protective effect on cancer development. We have thus uncovered a novel regulator of B cell lineage specification that may potential applications in B cell cancer therapy
Project description:The process of generating new neurons at the hippocampal neurogenic niche, also referred to as adult hippocampal neurogenesis (AHN), is impaired in Alzheimer’s disease (AD). MicroRNA-132 (miR-132), the most consistently downregulated microRNA (miRNA) in AD, was recently identified as a potent regulator of AHN, exerting multilayered proneurogenic effects in adult neural stem cells (NSCs) and their progeny. Supplementing miR-132 in AD mouse brain restores AHN and relevant memory deficits, yet the exact mechanisms involved are still unknown. Here, we identify NACC2 as a novel miR-132 target implicated in both AHN and AD. miR-132 deficiency in mouse hippocampus induces Nacc2 expression and inflammatory signaling in adult NSCs. We show that miR-132-dependent regulation of NACC2 is involved in the initial stages of human NSC differentiation towards astrocytes and neurons. Later, NACC2 function in astrocytic maturation becomes uncoupled from miR-132. We demonstrate that NACC2 is present in reactive astrocytes surrounding amyloid plaques in mouse and human AD hippocampus, and that there is an anticorrelation between miR-132 and NACC2 levels in AD and upon induction of inflammation. Unraveling the molecular mechanisms by which miR-132 regulates neurogenesis and cellular reactivity in AD, will provide valuable insights towards its possible application as a therapeutic target.
Project description:The colonization of distant organs by metastatic carcinoma cells underpins most human cancer-related deaths, including those from head and neck squamous cell carcinoma (HNSCC). We report that miR-203, a miRNA that promotes keratinocyte differentiation, is necessary and sufficient to inhibit multiple post-extravasation events during HNSCC lung metastasis, including initial survival/engraftment, escape from metastatic dormancy, and overt colonization in vivo. Restoration of miR-203 expression in established lung metastases reduces overall metastatic burden. Instead of promoting differentiation, miR-203 controls lung metastasis through direct targeting of genes involved in cytoskeletal dynamics (LASP1), ECM remodeling (SPARC), and cell metabolism (NUAK1). Expression of miR-203 and its downstream targets correlates with HNSCC overall survival outcomes, suggesting the therapeutic potential of targeting this signaling axis.