ABSTRACT
BACKGROUND: Lung cancer is one of the important health threats worldwide, of which 5-year survival rate is less than 15%. Non-small-cell lung cancer (NSCLC) accounts for about 80% of all lung cancer with high metastasis and mortality. METHODS: Cisplatin loaded multiwalled carbon nanotubes (Pt-MWNTS) were synthesized and used to evaluate the anticancer effect in our study. The NSCLC cell lines A549 (cisplatin sensitive) and A549/DDP (cisplatin resistant) were used in our in vitro assays. MTT was used to determine Cancer cells viability and invasion were measured by MTT assay and Transwell assay, respectively. Apoptosis and epithelial-mesenchymal transition related marker proteins were measured by western blot. The in vivo anti-cancer effect of Pt-MWNTs were performed in male BALB/c nude mice (4-week old). RESULTS: Pt-MWNTS were synthesized and characterized by X-ray diffraction, Raman, FT-IR spectroscopy and scan electron microscopy. No significant cytotoxicity of MWNTS was detected in both A549/DDP and A549 cell lines. However, Pt-MWNTS showed a stronger inhibition effect on cell growth than free cisplatin, especially on A549/DDP. We found Pt-MWNTS showed higher intracellular accumulation of cisplatin in A549/DDP cells than free cisplatin and resulted in enhanced the percent of apoptotic cells. Western blot showed that application of Pt-MWNTS can significantly upregulate the expression level of Bax, Bim, Bid, Caspase-3 and Caspase-9 while downregulate the expression level of Bcl-2, compared with free cisplatin. Moreover, the expression level of mesenchymal markers like Vimentin and N-cadherin was more efficiently reduced by Pt-MWNTS treatment in A549/DDP cells than free cisplatin. In vivo study in nude mice proved that Pt-MWNTS more effectively inhibited tumorigenesis compared with cisplatin, although both of them had no significant effect on body weight. CONCLUSION: Pt-MWNT reverses the drug resistance in the A549/DDP cell line, underlying its possibility of treating NSCLC with cisplatin resistance.
ABSTRACT
The present study identified that fibroblast growth factor receptor 3 (FGFR3) was significantly upregulated in bone metastasis of lung adenocarcinoma. RNA interference (RNAi) is a powerful approach for treating a wide range of human diseases, including cancer, through downregulating the expression of selected genes. In the present study, the invasiveness of A549 cells cultured in vitro was altered by small interfering (si)RNA targeting FGFR3, and the regulatory effect of silencing FGFR3 on the expression levels of E-cadherin and matrix metalloproteinase (MMP)9 was investigated. Human lung adenocarcinoma A549 cells were transfected with synthetic specific siRNAs targeting a fragment of the FGFR3 gene (namely, siRNA-855, siRNA-1447 and siRNA-2076) or with negative control (NC) siRNA. Cells were divided into five groups (A, siRNA-855 group; B, siRNA-1447 group; C, siRNA-2076 group; D, NC-siRNA group; and E, blank control group). The effect of the above siRNAs targeting FGFR3 on the invasion capacity of A549 cells was detected by Transwell assay. siRNAs against FGFR3 were transfected into A549 cells with by Lipofectamine® 2000, and the expression levels of FGFR3, E-cadherin and MMP9 were measured by reverse transcription-quantitative polymerase chain reaction and western blot assay. The experimental findings indicated that the expression levels of FGFR3 and MMP9 were significantly reduced in the siRNA-FGFR3-transfected groups (A-C groups), compared with those in the D and E groups (P<0.01). In addition, the expression levels of E-cadherin were markedly elevated in the A-C groups, compared with those in the D and E groups (P<0.01). There was no significant difference in E-cadherin expression between the A-C groups, or between the D and E groups (P>0.05). These results indicated that siRNA-FGFR3 was able to decrease the invasiveness of A549 cells, inhibit the expression of MMP9 and increase the expression of E-cadherin by downregulating the expression of FGFR3. Taken together, the results of the present study indicated that the upregulation of E-cadherin expression and the downregulation of MMP9 expression are able to inhibit the migration of A549 cells, and siRNA silencing FGFR3 acts as a tumor suppressor in these cells.
