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2.
Exp Cell Res ; 350(1): 199-209, 2017 Jan 01.
Article in English | MEDLINE | ID: mdl-27908592

ABSTRACT

Previously, we reported that GPR30 activation by the receptor-specific, non-estrogenic ligand G-1 inhibited in vitro and in vivo growth of prostate cancer (PCa) cells via sustained Erk1/2 activation. Mechanism underlying the sustained Erk1/2 activation for PCa cell growth inhibition remains unclear. Here we report that G-1, through GPR30, activated Gαi1 proteins to sustain Erk1/2 activation but failed to activate adenylyl cyclase (AC) for cAMP production in PCa cells. The chemical-induced activation of AC-cAMP-PKA signaling attenuated Erk1/2 activity and blocked the cell growth inhibitory effects of G-1. Furthermore, PCa predominantly expressed Gαi1 proteins. Silencing of Gαi1 expression blocked the inhibitory effects of G-1 on PCa cell growth. By gene expression profiling, GPR30 activation by G-1 interfered expression of cell cycle regulators and machinery elements to modulate PCa cell growth and the RACGAP1 interactome to control metastatic properties. In this regard, we demonstrated that G-1 inhibited PCa cell migration and invasion with reduced formations of filopodia and stress fibers through a GPR30-dependent pathway. Taken together, our findings revealed the underlying mechanism for sustaining Erk1/2 activation upon GPR30 activation by G-1 in PCa cells and the GPR30-mediated pathways in controlling PCa cell growth and metastatic properties.


Subject(s)
GTP-Binding Protein alpha Subunits, Gi-Go/metabolism , MAP Kinase Signaling System/physiology , Receptors, Estrogen/metabolism , Receptors, G-Protein-Coupled/metabolism , Adenylyl Cyclases/metabolism , Cell Cycle/physiology , Cell Proliferation/physiology , Estrogens/metabolism , Humans , Male , Mitogen-Activated Protein Kinase 1/metabolism , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/pathology
3.
Neuropathol Appl Neurobiol ; 41(2): 145-64, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25041637

ABSTRACT

AIMS: MicroRNAs (miRNAs) are an abundant group of small non-coding RNAs that have been implicated in tumorigenesis. They regulate expression of target genes by complementary base pairing. The purposes of this study were to delineate miR-106b expression in medulloblastoma (MB) and to explore its functional contributions to MB pathogenesis. METHODS: We analysed expression of miR-106b in 32 MB samples by quantitative RT-PCR. We applied gain- and loss-of-function strategies to delineate the functional roles of miR-106b in MB. Luciferase reporter assay was conducted to confirm target gene of miR-106b. RESULTS: Expression of miR-106b was overexpressed in MB, and was significantly associated with its host gene MCM7 (P = 0.020). Transfection of miR-106b inhibitor in MB cell lines markedly reduced cell proliferation, migration and invasion potential, and tumour sphere formation. Cell cycle analysis indicated that miR-106b inhibition induced G1 arrest and apoptosis. The cell cycle regulators, p21 and cyclin D1, and apoptotic marker cleaved PARP were differentially expressed in miR-106b inhibitor-transfected cells. PTEN was identified as a direct target gene of miR-106b. Luciferase reporter assay confirmed miR-106b directly interacted with the 3' UTR of PTEN. We found miR-106b directly targeted PTEN at transcriptional and translational levels. Immunohistochemistry revealed a trend between PTEN and miR-106b in MB tumours (P = 0.07). CONCLUSIONS: These data suggested the upregulation of miR-106b in MB and the involvement of miR-106b in MB biology.


Subject(s)
Cerebellar Neoplasms/genetics , Gene Expression Regulation, Neoplastic/genetics , Medulloblastoma/genetics , MicroRNAs/biosynthesis , PTEN Phosphohydrolase/metabolism , Adolescent , Adult , Blotting, Western , Cell Line, Tumor , Cerebellar Neoplasms/metabolism , Child , Female , Humans , Immunohistochemistry , Male , Medulloblastoma/metabolism , MicroRNAs/analysis , Real-Time Polymerase Chain Reaction , Transfection , Up-Regulation , Young Adult
4.
PLoS One ; 9(5): e98037, 2014.
Article in English | MEDLINE | ID: mdl-24837491

ABSTRACT

Fulvestrant (ICI-182,780) has recently been shown to effectively suppress prostate cancer cell growth in vitro and in vivo. But it is unclear whether microRNAs play a role in regulating oncogene expression in fulvestrant-treated prostate cancer. Here, this study reports hsa-miR-765 as the first fulvestrant-driven, ERß-regulated miRNA exhibiting significant tumor suppressor activities like fulvestrant, against prostate cancer cell growth via blockage of cell-cycle progression at the G2/M transition, and cell migration and invasion possibly via reduction of filopodia/intense stress-fiber formation. Fulvestrant was shown to upregulate hsa-miR-765 expression through recruitment of ERß to the 5'-regulatory-region of hsa-miR-765. HMGA1, an oncogenic protein in prostate cancer, was identified as a downstream target of hsa-miR-765 and fulvestrant in cell-based experiments and a clinical study. Both the antiestrogen and the hsa-miR-765 mimic suppressed HMGA1 protein expression. In a neo-adjuvant study, levels of hsa-miR-765 were increased and HMGA1 expression was almost completely lost in prostate cancer specimens from patients treated with a single dose (250 mg) of fulvestrant 28 days before prostatectomy. These findings reveal a novel fulvestrant signaling cascade involving ERß-mediated transcriptional upregulation of hsa-miR-765 that suppresses HMGA1 protein expression as part of the mechanism underlying the tumor suppressor action of fulvestrant in prostate cancer.


Subject(s)
Antineoplastic Agents, Hormonal/pharmacology , Cell Movement , Cell Proliferation , Estradiol/analogs & derivatives , Estrogen Receptor Antagonists/pharmacology , MicroRNAs/metabolism , Prostatic Neoplasms/metabolism , Antineoplastic Agents, Hormonal/therapeutic use , Cell Line, Tumor , Estradiol/pharmacology , Estradiol/therapeutic use , Estrogen Receptor Antagonists/therapeutic use , Estrogen Receptor beta/antagonists & inhibitors , Estrogen Receptor beta/metabolism , Fulvestrant , HMGA Proteins/genetics , HMGA Proteins/metabolism , Humans , Male , MicroRNAs/genetics , Neoplasm Invasiveness , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/pathology , Up-Regulation
5.
Acta Neuropathol ; 123(4): 553-71, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22249617

ABSTRACT

Overexpression of high mobility group AT-hook 1 (HMGA1) is common in human cancers. Little is known about the mechanisms underlying its deregulation and downstream targets, and information about its clinical and biological significance in medulloblastoma (MB) is lacking. Here, we demonstrated frequent genomic gain at 6p21.33-6p21.31 with copy number increase leading to overexpression of HMGA1 in MB. The overexpression correlated with a high proliferation index and poor prognosis. Moreover, we found that hsa-miR-124a targeted 3'UTR of HMGA1 and negatively modulated the expression in MB cells, indicating that loss/downregulation of hsa-miR-124a reported in our previous study could contribute to the overexpression. Regarding the biological significance of HMGA1, siRNA knockdown and ectopic expression studies revealed the crucial roles of HMGA1 in controlling MB cell growth and migration/invasion through modulation of apoptosis and formation of filopodia and stress fibers, respectively. Furthermore, we identified cdc25A as a target of HMGA1 and showed that physical interaction between HMGA1 and the cdc25A promoter is required for transcriptional upregulation. In clinical samples, HMGA1 and cdc25A were concordantly overexpressed. Functionally, cdc25A is involved in the HMGA1-mediated control of MB cell growth. Finally, netropsin, which competes with HMGA1 in DNA binding, reduced the expression of cdc25A by suppression of its promoter activity and inhibited in vitro and in vivo intracranial MB cell growth. In conclusion, our results delineate the mechanisms underlying the deregulation and reveal the functional significance of HMGA1 in controlling MB cell growth and migration/invasion. Importantly, the results highlight the therapeutic potential of targeting HMGA1 in MB patients.


Subject(s)
Cell Movement/genetics , Cell Proliferation , Cerebellar Neoplasms/metabolism , Gene Expression Regulation, Neoplastic/genetics , HMGA1a Protein/metabolism , Medulloblastoma/metabolism , cdc25 Phosphatases/metabolism , Actin Cytoskeleton/metabolism , Animals , Antiviral Agents/pharmacology , Cell Line, Tumor , Cell Movement/drug effects , Cell Proliferation/drug effects , Cerebellar Neoplasms/genetics , Cerebellar Neoplasms/mortality , Cerebellar Neoplasms/pathology , Chromatin Immunoprecipitation , Chromosome Aberrations , Chromosomes, Human, Pair 17 , Chromosomes, Human, Pair 6 , Dose-Response Relationship, Drug , Electrophoretic Mobility Shift Assay , Female , Flow Cytometry , Gene Expression Profiling , Gene Expression Regulation, Neoplastic/drug effects , Gene Knockout Techniques , HMGA1a Protein/genetics , Humans , Male , Medulloblastoma/genetics , Medulloblastoma/mortality , Medulloblastoma/pathology , Mice , Mice, Nude , Neoplasm Invasiveness/pathology , Netropsin/pharmacology , Oligonucleotide Array Sequence Analysis , RNA, Messenger/metabolism , RNA, Small Interfering/genetics , RNA, Small Interfering/metabolism , Signal Transduction/drug effects , Signal Transduction/genetics , Survival Analysis , Time Factors , Xenograft Model Antitumor Assays , cdc25 Phosphatases/genetics
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