Inhibition of Nemo-like Kinase Increases Taxol Sensitivity in Laryngeal Cancer

Abstract

Several studies have shown that nemo-like kinase (NLK) plays a vital role in apoptosis of cancer cells. Thepresent research concerned effects and mechanisms of Taxol on NLK knockdown human laryngeal cancerHep-2cell lines in vitro. Using RNAi, methyl-thiazoltetrazolium (MTT) assays, real-time RT-PCR, Western blotting andflow cytometry analysis, growth and the cell cycle progression of NLK knockdown Hep-2 cells and expression ofdownstream molecules were observed. Cell growth was obviously suppressed in the Taxol treated group (P<0.001,48 hours). Cell numbers of combined Taxol-based chemotherapy with lentivirus mediated RNAi treatmentgroup (Lv-shNLK+Taxol goup) were significantly different from NLK-specific siRNA lentivirus infected group(Lv-shNLK group) (p<0.001). Flow cytometry analysis revealed that Lv-shNLK+Taxol caused the G0/G1-phaseDNA content to decrease from 44.1 to 3.33% (p<0.001) and the S-phase DNA content to increase from 38.4 to82.0% (p<0.001), in comparison with the Lv-shNLK+Taxol group. Immunoblot analysis showed that knockdownof NLK led to significant reduction in the levels of cyclin D1, PCNA and PARP, whereas cyclin B1 was elevatedin. Cell growth was also obviously suppressed in the Hep-2 cell line, knockdown of NLK making them moresensitive to Taxol treatment. NLK is expected to become a target of new laryngeal cancer gene therapies.