AXIN1-related CSRNP1 mRNA expression and its transcriptional regulation in TGF-β1-induced tumor cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate AXIN1-related CSRNP1 gene expression and the mechanism of its transcriptional regulation in TGF-β1-induced tumor cells.</p><p><b>METHODS</b>Human lung carcinoma A549 cells or human prostate cancer PC3 cells were treated with TGF-β1 at different doses (0, 20, 40, and 80 ng/ml) or at 20 ng/ml for 0, 8, 12, or 24 h, and the dose and time effect of TGF-β1 on CSRNP1 mRNA expression in the tumor cells were evaluated with real-time RT-PCR. A549 cells were also treated with TGF-β1 and cycloheximide to clarify whether CSRNP1 expression induced by TGF-β1 required de novo protein synthesis. A549 cells transfected with pcDNA3.1, flag-SMAD3, or flag-SMAD3-mu, after serum starvation, were treated with or without TGF-β1 (20 ng/mL) for 24 h, and the overexpression of wild-type SMAD3 and dominant negative SMAD3-mu mutant were confirmed by Western blotting. The effect of SMAD3 or SMAD3-mu overexpression on CSRNP1 mRNA expression was also measured by real-time RT-PCR.</p><p><b>RESULTS</b>In both A549 and PC3 cells, TGF-β1 dose- and time-dependently stimulated CSRNP1 expression, which required de novo protein synthesis in A549 cells. Overexpression of wild-type SMAD3 significantly increased the expression of CSRNP1 mRNA induced by TGF-β1, while overexpression of dominant negative SMAD3 mutant remarkably reduced CSRNP1 mRNA expression in response to TGF-β1 in A549 cells.</p><p><b>CONCLUSION</b>TGF-β1 may contribute to CSRNP1 expression through SMAD3 activation and downstream signaling in tumor cells.</p>

Functional role of protein kinase D1 in Aspergillus fumigatus-induced activation of nuclear factor-κB signal pathway and transcription / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the functional role of protein kinase D1 (PKD1) in the activation of nuclear factor-κB (NF-κB) signal pathway and NF-κB transcription mediated by Aspergillus fumigatus.</p><p><b>METHODS</b>A549 cells and HEK293 cells were transfected with green fluorescence protein (GFP) or GFP-PKD1 followed by treatment with 1×10(5) CFU/ml Aspergillus fumigatus conidia for different time lengths. The phosphorylation levels of PKD1, IκB and p65 (pS276) in the transfected cells were measured by Western blotting. A549 cells were transfected with GFP-PKD1 or siRNA-PKD1, and the phosphorylation of IκB and p65 (pS276) was examined. Finally, NF-κB-luc and renilla luciferase reporter pRL-SV40 were cotransfected into GFP- or GFP-PKD1-transfected A549 cells before exposure of the cells to Aspergillus fumigatus conidia for 24 h, and NF-κB transcriptional activity in the cells was determined using dual-luciferase reporter assay.</p><p><b>RESULTS</b>Overexpression of PKD1 significantly increased Aspergillus fumigatus conidia-stimulated phosphorylation of PKD1, IκB and p65 (pS276), whereas PKD1 knockdown by siRNA-PKD1 suppressed IκB and p65 (pS276) phosphorylation. Dual luciferase assay demonstrated that PKD1 overexpression markedly enhanced Aspergillus fumigatus-induced NF-κB transcription in A549 cells.</p><p><b>CONCLUSION</b>PKD1 may contribute to the activation of NF-κB signal pathway and NF-κB transcription induced by Aspergillus fumigatus.</p>