ABSTRACT
The bioengineered luciferase reporter has been widely used for monitoring of a variety of molecular events in living cells because of their ability to provide highly sensitive quantitation with broad linearity. In the present study, we made a cyclin A2-luciferase (CYCA-Luc) fusion protein and examined the utility of this optical reporter for monitoring G2-phase cell cycle arrest in living animals. In vitro luciferase assay and in vivo bioluminescence imaging assay showed that the lithium chloride (LiCl), G2-phase-specific drug, induced G2-phase arrest of cell cycle and increased the activity of this reporter under in vitro or in vivo conditions, and this reporter can also be potentially used in high-throughput screening efforts aimed at discovering novel anti-cancer drugs that will cause cell cycle arrest at the G2-phase in cultivated cell lines and animal models.
Subject(s)
Cyclin A2/genetics , G2 Phase Cell Cycle Checkpoints , Genes, Reporter , Luciferases/genetics , Optical Imaging , Uterine Cervical Neoplasms/pathology , Animals , Cyclin A2/biosynthesis , Female , G2 Phase Cell Cycle Checkpoints/drug effects , HeLa Cells , High-Throughput Screening Assays , Humans , Lithium Chloride/pharmacology , Luciferases/biosynthesis , Luminescent Measurements , Mice, Inbred BALB C , Mice, Nude , Recombinant Fusion Proteins/biosynthesis , Recombinant Fusion Proteins/genetics , Uterine Cervical Neoplasms/drug therapy , Uterine Cervical Neoplasms/genetics , Uterine Cervical Neoplasms/metabolism , Xenograft Model Antitumor AssaysABSTRACT
Accumulating evidence indicates that epithelial splicing regulatory protein 1 (ESRP1) can inhibit the epithelial-to-mesenchymal transition (EMT), thus playing a central role in regulating the metastatic progression of tumors. However, it is still not clear whether ESRP1 directly influences the cell cycle, or what the possible underlying molecular mechanisms are. In this study, we showed that ESRP1 protein levels were significantly correlated with the Ki-67 proliferative index (r = -0.521; p < 0.01), and that ESRP1 overexpression can significantly inhibit cervical carcinoma cell proliferation and induced G1-phase arrest by downregulating cyclin A2 expression. Importantly, ESRP1 can bind to GGUGGU sequence in the 3'UTR of the cyclin A2 mRNA, and ESRP1 overexpression significantly decreases the stability of the cyclin A2 mRNA. In addition, our experimental results confirm that ESRP1 overexpression results in enhanced CDC20 expression, which is known to be responsible for cyclin A2 degradation. This study provides the first evidence that ESRP1 overexpression induces G1-phase cell cycle arrest via reducing the stability of the cyclin A2 mRNA, and inhibits cervical carcinoma cell proliferation. The findings suggest that the ESRP1/cyclin A2 regulatory axis may be essential as a regulator of cell proliferation, and may thus represent an attractive target for cervical cancer prevention and treatment.
