Lentivirus-mediated RNA interference targeting the H19 gene inhibits cell proliferation and apoptosis in human choriocarcinoma cell line JAR.

BACKGROUND: H19 is a paternally imprinted gene that has been shown to be highly expressed in the trophoblast tissue. Results from previous studies have initiated a debate as to whether noncoding RNA H19 acts as a tumor suppressor or as a tumor promotor in trophoblast tissue. In the present study, we developed lentiviral vectors expressing H19-specific small interfering RNA (siRNA) to specifically block the expression of H19 in the human choriocarcinoma cell line JAR. Using this approach, we investigated the impact of the H19 gene on the proliferation, invasion and apoptosis of JAR cells. Moreover, we examined the effect of H19 knockdown on the expression of insulin-like growth factor 2 (IGF2), hairy and enhancer of split homologue-1 (HES-1) and dual-specific phosphatase 5 (DUSP5) genes. RESULTS: H19 knockdown inhibited apoptosis and proliferation of JAR cells, but had no significant impact on cell invasion. In addition, H19 knockdown resulted in significant upregulation of HES-1 and DUSP5 expression, but not IGF2 expression in JAR cells. CONCLUSIONS: The finding that H19 downregulation could simultaneously inhibit proliferation and apoptosis of JAR cells highlights a putative dual function for H19 in choriocarcinoma and may explain the debate on whether H19 acts as a tumor suppressor or a tumor promotor in trophoblast tissue. Furthermore, upregulation of HES-1 and DUSP5 may mediate H19 downregulation-induced suppression of proliferation and apoptosis of JAR cells.

The expression pattern of ADP-ribosyltransferase 3 in rat traumatic brain injury.

Mammalian ecto ADP-ribosyltransferases (ARTs) can regulate the biological functions of various types of cells by catalyzing the transfer of single ADP-ribose moiety from NAD+ to a specific amino acid in a target protein. ART3 is a member of the known ART family which is involved in cell division, DNA-repair and the regulation of the inflammatory response. To elucidate the expression, cellular localization and possible functions of ART3 in central nervous system (CNS) lesion and repair, we performed an acute traumatic brain injury model in adult rats. Western blot analysis showed that the expression of ART3 in ipsilateral brain cortex increased, then reached a peak at day 3 after traumatic brain injury (TBI), and gradually declined during the following days. But in the contralateral brain cortex, no obvious alterations were observed. Immunohistochemistry revealed the highly significant accumulation of ART3 at the ipsilateral brain in comparison to contralateral cerebral cortex. Double immunofluorescence labeling suggested that ART3 was localized mainly in the plasmalemma of neurons, but not in astrocytes or microglias within 3 mm from the lesion site at day 3 post-injury. In addition, we detected the expression profiles of caspase-3 and growth associated protein 43 (GAP-43) whose changes were correlated with the expression profiles of ART3 in this TBI model. Besides, co-localization of ART3/active caspase-3 and ART3/GAP43 were detected in NeuN-positive cells, respectively. Moreover, Pheochromocytoma (PC12) cells were treated with H2O2 to establish an apoptosis model. The results showed that the expression of ART3 was increased in the concentration and time dependence way. To further examine the involvement of ART3 in apoptosis of PC12, 3-Methoxybenzamide was used in flow cytometry analysis of apoptotic cells stained with Annexin V and PI. The experimental group in which 3-Methoxybenzamide used had a relative low level of apoptotic index compared with the untreated group. Together with previous reports, we hypothesize that ART3 may play important roles in CNS pathophysiology after TBI and further research is needed to have a good understanding of its function and mechanism.