Niflumic acid (NFA) was known to inhibit cell proliferation or migration in several types of cancer. However, the function of NFA in human nasopharyngeal carcinoma (NPC) cells was not clarified. The proliferation of NPC cell line CNE-2Z cells with NFA treatment was detected using the cell counting kit-8 method and transwell assay was employed to assess the effect of NFA on the CNE-2Z cell migration and invasion. The activity of MMP2 and MMP9 was detected by Gelatin Zymography. Cell cycle distribution and apoptosis were detected using flow cytometry. In vitro pull-down assay, western blot, and computational technique were applied to investigate the NFA regulating signaling pathway. Our results indicated that the growth capacity and colony formation potential of CNE-2Z cells in soft agar were significantly suppressed by treatment with NFA. NFA inhibited the proliferation of CNE-2Z cells in a concentration and time-dependent manner. NFA exerted an S phase arrest on the CNE-2Z cells in a concentration-dependent manner, while promoting apoptosis in a dose-dependent manner. Migration and invasion potential of CNE-2Z cells were decreased by NFA treatment in vitro. In vitro pull-down assay and molecular modeling indicated that NFA directly bound with early respond kinase 1 (ERK1). Finally, the anti-tumor effect of NFA was suggested to be mediated by inhibiting early respond kinases (ERK) expression and the MMP2 and MMP9 activities. NFA has proliferation-inhibiting, invasion-suppressing, cell cycle-blocking and apoptosis-promoting effects on CNE-2Z cells through regulation of ERK/MAPK and our results indicates that NFA may serve as a candidate of anticancer drug for NPC.
Keywords: MAPK/ERK; MMP2; MMP9; Niflumic acid (NFA); molecular modeling; nasopharyngeal carcinoma.