Long noncoding RNA RP4 functions as a competing endogenous RNA through miR-7-5p sponge activity in colorectal cancer

AIM To investigate the role of long noncoding RNA(lnc RNA) RP4 in colorectal cancer.METHODS Lentivirus-mediated lnc RNA RP4 overexpression and knockdown were performed in the colorectal cancer cell line SW480. Cell proliferation, tumor growth, and early apoptosis were evaluated by a cell counting kit-8 assay, an in vivo xenograft tumor model, and annexin V/propidium iodide staining, respectively. Analysis of the lnc RNA RP4 mechanism involved assessment of the association of its expression with mi R-7-5 p and the SH3 GLB1 gene. Western blot analysis was also performed to assess the effect of lnc RNA RP4 on the autophagy-mediated cell death pathway and phosphatidylinositol-3-kinase(PI3 K)/Akt signaling.RESULTS Cell proliferation, tumor growth, and early apoptosis in SW480 cells were negatively regulated by lnc RNA RP4. Functional experiments indicated that lnc RNA RP4 directly upregulated SH3 GLB1 expression by acting as a competing endogenous RNA(ce RNA) for mi R-7-5 p. This interaction led to activation of the autophagy-mediated cell death pathway and de-repression of PI3 K and Akt phosphorylation in colorectal cancer cells in vivo.CONCLUSION Our results demonstrated that lnc RNA RP4 is a ce RNA that plays an important role in the pathogenesis of colorectal cancer, and could be a potential therapeutic target for colorectal cancer treatment.

On the weak Lyα emission line of BL Lacertae objects

Recent studies reveal that weak Lyα emission line may be a ubiquitous feature of nearby BL Laceratae objects(BL Lacs). We present a survey of the Lyα emission lines in BL Lacs, with a focus on data obtained by the Cosmic Origins Spectrograph onboard the Hubble Space Telescope. Among the11 selected targets, seven show a clear detection of the intrinsic Lyα emission line, while one manifests a marginal detection. Two of these intrinsic Lyα lines are newly detected in this work(FBQS J1217+3007 and3 C 66 A). Most selected BL Lacs are either high or intermediate-frequency peaked BL Lacs, with the only exception being one low-frequency peaked BL Lac. A strong anti-correlation between the line equivalent width and the continuum luminosity was found. The possible sources of ionizing photons that are responsible for production of the Lyα emission line are studied based on a widely accepted detailed accretion-jet model. It is found that the clouds of the broad line region are unlikely to be located in the jet cone region with an inclination angle of less than 10 degrees. Contributions from the jet and disk to the emission lines are found to be comparable. Additionally, a possible way to constrain the accretion rate from the emission line is proposed.