The influence of kinesin light chain-2 on the radiosensitivity of non-small cell lung cancer cells and the underlying mechanisms.

e14512 Background: Our previous study found upregulated kinesin light chain-2 (KLC2) in non-small cell lung cancer (NSCLC) cell lines and tissues, which is associated with a poor prognosis. KLC2 promotes the migration ability of lung cancer cells. However, the influence of KLC2 on radiosensitivity of NSCLC has not yet been reported. Methods: Sensitivity of lung cancer cells to radiation was analyzed by colony formation, γH2AX immunofluorescent staining assay and neutral comet assay in vitro and a xenograft tumor model in vivo. Gene set enrichment analysis (GSEA), qRT-PCR and western blot assay were performed to predict and validate the potential target genes of KLC2. Results: We found that down-regulation of KLC2 could significantly improve the radio-sensitivity of lung cancer cells, while the overexpression of KLC2 had the opposite effect. GSEA identified p53 signal pathway as differentially enriched with high KLC2 expression, which was validated by western blot assay. Using data from TCGA, we found a positive correlation between the mRNA level of KLC2 and that of HuR. The expression of KLC2 mRNA and protein in lung cancer cells was significantly reduced when downregulating HuR. Interestingly, the overexpression of KLC2 could also significantly decrease the expression of HuR. Conclusions: The above results indicated that HuR could upregulate the expression of KLC2, which might decrease the phosphorylation of p53 and thereby weakened the radio-sensitivity of NSCLC cells. KLC2 could also positively regulate the expression of HuR as a positive feedback. Support: 81572279, 2016J004, LC2016PY016, 2018CR033