| Background:Lung cancer is a malignant tumor which severely threatens the human health. Epidemiological data show that lung cancer leads all other cancers in both incidence and mortality. Although there are some treatments for non-small cell lung cancer (NSCLC) by the chemotherapy, radiotherapy, nutrition support and so on, the overall survival rate of lung cancer in five-year is still less than 15%. Therefore, exploring the new methods for lung cancer cure is of great significance.Nuclear transcription factorκB (NF-κB) is a transcript factor existing ubiquitously in the biosphere. It is a convergence point of a variety of signal transduction pathway. NF-κB is capable of regulating immunity, inflammation, cell proliferation and differentiation. In recent years, studies have shown that NF-κB is associated with the regulation of apoptosis, tumor occurrence, development, invasion, metastasis and chemo-/-radio resistance. Analysis of the COX-2 and CylinDl genes sequence revealed that there were two NF-κB binding sites on the COX-2 and CyclinD1 gene promoter. The inhibition of protein expression of NF-κB binding sites could reduce the expression of COX-2 and cyclinD1. It indicated that NF-κB may play an important role in the process of induction COX-2 and CyclinDl gene transcription and protein expression.Decoy oligodeoxynucleotides technology has been reported to be a powerful tool for studying gene regulation in vitro and in vivo. Decoy oligodeoxynucleotides could bind competitively with transcription factor specific consistent sequences to weaken the binding of transcription factor and target gene promoter, thus down regulating the target gene expression.Objective:To provide evidence for clinical application, we investigated the effects and mechanisms of nuclear factor-KB decoy oligodeoxynucleotides and DDP on lung cancer cells A549.Methods:1. The treatments of lung cancer cells A549 were divided into four groups:blank control group, liposome control group, decoy ODNs group and scramble decoy ODNs group, the expression of NF-κBp65 proteins were examined by immunohistochemistry 48 hours after treatment of A549 lung cancer cell.2. The treatments of lung cancer cells A549 were divided into four groups:blank control group, decoy ODNs group, cisplatin group and decoy ODNs plus cisplatin group,48 hours after treatment of A549 lung cancer cell, the level of expression of CyclinD1mRNA was examined by semiquantitative reverse transcription polymerase chain reaction (RT-PCR). The expression of COX-2 protein was examined by immunohistochemistry. Cell cycle was examined by Flow Cytometer. Results:1. After decoy ODNs transfection, the expression of NF-κB P65 protein was examined by immunohistochemistry, it showed that the expressions of NF-κB p65 protein in the control group, liposome control group and scramble decoy ODNs group was significantly higher compared with decoy ODNs group (P<0.05). There was no statistical significant difference among three groups (P>0.05).2. The level of expression of cyclindlmRNA was examined by semi-quantitative RT-PCR. Compared with the control group, the expression of CyclinDl was reduced in decoy ODNs plus cisplatin group, cis-platinum group and decoy ODNs group (P<0.05). Compared with cis-platinum group and decoy ODNs group, the expression of cyclindlmRNA in decoy ODNs plus cisplatin group was significantly reduced, the difference was statistically significant (P<0.05). Compared with decoy ODNs group, the expression of cyclindlmRNA was significantly reduced in cisplatin group, the difference was statistically significant (P<0.05).3. The expression of COX-2 protein were examined by immunohistochemistry, Compared with the control group, the expression of COX-2 was reduced in decoy ODNs plus cisplatin group, cis-platinum group and decoy ODNs group(P<0.05).Compared with cis-platinum group and decoy ODNs group, the expression of COX-2 was significantly reduced in decoy ODNs plus cisplatin group, the difference was statistically significant (P<0.05). Compared with decoy ODNs group, the expression of COX-2 was significantly reduced in cisplatin group, the difference was statistically significant (P<0.05).4. Cell cycle was examined by Flow Cytometer.Compared with the control group, the proportion of S phase cells was gradually increased in the decoy ODNs group, cis-platinum group and decoy ODNs plus cisplatin group, the difference was statistically significant (P<0.05). Compared with cis-platinum group and decoy ODNs group, the proportion of S phase cells was significantly increased in decoy ODNs plus cisplatin group, the difference was statistically significant (P<0.05). Compared with decoy ODNs group, the proportion of S phase cells was significantly increased in cisplatin group, the difference was statistically significant (P<0.05).Conclusion:1. NF-κB decoy ODNs had a significant inhibition on the expression of NF-KBp65 proteins in A549 lung cancer cell, suggesting that NF-kB decoy ODNs inhibited the expression of NF-κB.2. NF-κB decoy ODNs and cisplatin can inhibit the expression of CyclinDl and COX-2. After combination, the effect of the inhibition on the expression of CyclinDl and COX-2 was significantly enhanced, which suggests this effect was synergistic or additive.3. NF-κB decoy ODNs and cis-platinum can cause S-phase arrest in A549 cell. Decoy ODNs can enhance the effect of S phase arrest cause by cis-splatinum. It indicates that the NF-κB decoy ODNs can increased the A549 cells'sensitivity to cis-platinum.
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