Objective To study the effect of tubulin tyrosine ligase like 12 (TTLL12) and nitrotyrosine on the growth of prostate cancer cells. MethodsTTLL12 and α-tubulin nitrotyrosination (N-tubulin) were detected by Western blotting analysis in normal prostate epithelial cell lines PWR1E and RWPE1, and prostate cancer cell line DU145; the proliferation of cells was observed by MTT assay. ResultsThe expression of N-tubulin was significantly lower in DU145 cells than those in PWR1E and RWPE1 cells after treatment with nitrotyrosine (P＜0.05). The proliferation of PWR1E and RWPE1 cells treated with nitrotyrosine (cultured with 800 μmol/L nitrotyrosine) were significantly inhibited compared with the control (cultured with 800 μmol/L hydrochloric acid, P<0.05), while there was no visible change in the proliferation of DU145 cells. N-tubulin level was significantly higher in the experimental group (transfected with siTTLL-12) than the control group (transfected with siControl) after effective silence of TTLL12 (P＜0.05); the proliferation of DU145 cells treated with nitrotyrosine in the experimental group was significantly inhibited (P<0.05),while there was no visible change in cell proliferation in the control group (P>0.05). ConclusionTTLL12 allows an escape of prostate cancer cells from the treatment of nitrotyrosine,leading to the escape of prostate cancer cells from the body’s surveillance system and acquirement of their abnormal proliferation.