The potential markers of NK-92 associated to cytotoxicity against K562 cells

Markers associated to NK cytolytic activity are in a great need to regulate NK cell immunotherapy products. We assume that biomarkers which response to cytolysis will change their transcription, expression or secretion. To find NK-92 indicator to cytolytic activity, we have evaluated the potential markers by quantifying the expression of well-known cytotoxicity functional molecules (cytokine IFN-γ, Granzyme B, perforin, CD69 and CD107a), and explored candidate markers by a sweeping transcription picture of NK-92 using a direct cytolysis model (incubation with K562). We found that IFN-γ secretion was highly correlated to cytotoxicity of NK-92, neither Granzyme B, perforin secretion, nor CD69, CD107a positive population were upregulated by K562 stimulation. RNAseq revealed 432 genes expression changed during cytolysis, several genes (BIRC3, CSF2, VCAM1 and TNFRSF9) mRNA expression were validated by real time RT-PCR under K562 being killed or protected from being killed conditions. Results suggested IFN-γ secretion, BIRC3 and TNFRSF9 transcription in NK-92 were responsive to K562 cytolysis. In a word, our results confirmed one marker and reveal an array of novel candidate markers associated with NK-92 cytotoxicity. Further studies are greatly needed to determine the roles these new makers play in NK-92 cytolysis process.