ABSTRACT
Background: Anti-tumor effects of N-myc Downstream Regulated Gene2 (NDRG2) have been demonstrated in many tumors. In the present study, NDRG2 was specifically overexpressed in lung cancer cell line using Survivin Promoter (Sur-P). Then, the effects of NDRG2 overexpression on viability, apoptosis, migration, and invasion of A549 cells were evaluated. Methods: Recombinant pAdenoVator-Sur-P-NDRG2-IRES-GFP plasmid harboring NDRG2 gene under transcriptional control of Sur-P and mock plasmid were constructed. A549 lung tumor cells and LX-2 cells (non-tumor cell line) were transfected with pAdenoVator-Sur-P-NDRG2-IRES-GFP, pAdenoVator-CMV-NDRG2-IRES-GFP, or mock plasmids. Tumor specificity of Sur-P was evaluated using fluorescent microscopy for GFP expression. The effects of NDRG2 overexpression on cell viability, apoptosis, and migration of A549 cells were measured using MTT, annexinV/7-AAD flow cytometry, and transwell migration assay, respectively. NDRG2 and matrix metalloproteinase-2 (MMP-2) expression were measured using real time-PCR. Results: pAdenoVator-Sur-P-NDRG2-IRES-GFP transfection resulted in a huge GFP expression in A549 cells, but not in LX-2 cells. The results of real time-PCR analysis also showed that pAdenoVator-Sur-P-NDRG2-IRES-GFP transfection led to an abundant NDRG2 expression in A549 cells. NDRG2 overexpression decreased A549 cell viability through increasing cell apoptosis. In addition, migration, invasion, and MMP-2 expression decreased following NDRG2 overexpression in A549 cells. Conclusion: The findings indicate that the targeted overexpression of NDRG2 using Sur-P can reduce the viability and invasiveness of A549 cells, suggesting possible benefits of this approach in lung cancer therapy.
ABSTRACT
BACKGROUND: Despite the ease of conventional splicing by overlap-extension (SOEing) PCR technique in theory, when splicing more than two fragments, and especially if one of the complementary sequences is A-T rich, the attachment of the fragments would be challenging. A new rapid and highly efficient SOEing PCR assay was developed for simultaneous splicing of multiple DNA fragments and induction of site-directed mutagenesis in a single tube. METHODS: The method was adapted for splicing human beta-globin UTRs to OCT4, SOX2, KLF4, C-MYC, LIN28A, and destabilized GFP for the construction of chimeric DNA fragments for in vitro transcription. In addition, the native Kozak sequence of beta-globin (K1) was replaced by the strongest Kozak sequence (K2) using site-directed mutagenesis to enhance the expression of target genes. RESULTS: ChimericGFPd2/K1, GFPd2/K2, OCT4, and KLF4 were created by the optimized conventional SOEing PCR. The single tube method was able to create the chimeric SOX2, C-MYC, and LIN28A in high quality and quantity in comparison with the conventional SOEing PCR. Moreover, using single tube SOEing PCR, the reaction time and materials that are required in the conventional SOEing PCR were significantly reduced. Fluorescent microscopy and flow cytometry examinations indicated highly efficient translation of K2 sequence in comparison with the K1sequence. CONCLUSION: Single tube SOEing PCR is a valuable method to construct more multiple fragments with high yield. The method can successfully be applied for construction of various kinds of complex chimeric genes.
ABSTRACT
Metastasis to lymph nodes and distant organs is the main challenge in the treatment of papillary thyroid cancer. In the current investigation, we aimed to evaluate the synergistic effects of celecoxib (CX) and sodium valproate (VPA) against cell survival, invasiveness properties, and expression of metalloproteinase-2 and -9 (MMP-2 and MMP-9) in papillary thyroid cancer cell line, B-CPAP cells. The effect of CX and VPA on B-CPAP cells viability and apoptosis were investigated using MTT assay and annexin V/7-AAD flowcytometry, respectively. The effects of the drugs on invasiveness properties of B-CPAP cells and expression of MMP-2 and MMP-9 were evaluated using transwell assay and real time PCR, respectively. MTT assay showed that CX and VPA decreased viability of B-CPAP cells dose dependently (IC50 32.4µM and 6.8 mM, respectively). Combination of CX (5 µM) and VPA (2.5 and 5 mM) increased apoptosis, and reduced cell migration and invasion of B-CPAP cell, synergistically. Real time PCR results showed that both CX (5 µM) and VPA (2.5 and 5 mM) reduced MMP-2 expression (P < 0.05) but had no significant effects on the expression of MMP-9. Our findings suggest that CX and VPA synergistically increase apoptosis and suppress migration and invasion of B-CPAP cells through inhibition of MMP-2 expression.
