To investigate the effect of sestrin 2 (SESN2) on JS-1 cell activation through unc-51-like kinase 1 (ULK1) and its mechanism.

The JS-1 cells were divided into seven groups: the control group (cultured under normal conditions), si-NC group (transfected with si-NC), the si-SESN2 group (transfected with si-SESN2), model group (cultured in medium containing 5 μg·L^-1 transforming growth factor-β1 for 24 h), model + oe-SESN2 group (transfected with oe-SESN2 on the basis of the model group), model + si-SESN2 group (transfected with si-SESN2 on the basis of the model group), and model+si-SESN2 + oe-ULK1 group (co-transfected with si-SESN2 and oe-ULK1 on the basis of the model group). The levels of fibrous actin (F-actin) was detected by immunofluorescence. Quantitative real time polymerase chain reaction was used to detect the ULK1 mRNA level. The relevtive expression levels of SESN2, light chain 3 Ⅱ/Ⅰ (LC3Ⅱ/Ⅰ), connective tissue growth factor (CTGF), collagen type I α1 (Col1a1), phospho-c-Jun N-terminal kinase (p-JNK), c-Jun N-terminal kinase (JNK), c-Jun and activating transcription factor 2 (ATF2) were detected by Western Blot. Cell proliferation rate was detected by cell counting kit-8. Transwell assesses the ability of cells to invade.

The relative expression levels of SESN2 protein in the control group, model group, model+oe-SESN2 group, and model+si-SESN2 group were 1.00±0.19, 2.57±0.49, 3.61±0.68, and 1.66±0.31, respectively; the relative fluorescence intensity of F-actin was 1.00±0.18, 4.57±0.92, 6.33±1.19, and 2.81±0.57, respectively; the relative expression levels of ULK1 mRNA were 1.00±0.15, 2.67±0.48, 3.52±0.66, and 1.95±0.37, respectively. The relative expression levels of LC3Ⅱ/Ⅰ protein in the control group, model group, model+oe-SESN2 group, model+si-SESN2 group, and model+si-SESN2+oe-ULK1 group were 1.00±0.20, 2.79±0.53, 3.57±0.68, 1.88±0.35, and 2.51±0.48, respectively; the cell proliferation rates were (100.00±2.23)%, (141.31±4.17)%, (156.52±8.84)%, (109.49±7.35)%, and (127.08±8.16)%, respectively; the number of cell invasions was 66.04±11.45, 137.84±21.73, 215.19±35.28, 75.46±13.51, and 124.27±19.50, respectively; the relative expression levels of CTGF protein were 1.00±0.17, 2.65±0.51, 3.77±0.72, 1.51±0.29, and 2.53±0.51, respectively; the relative expression levels of Col1a1 protein were 1.00±0.15, 2.93±0.57, 3.88±0.75, 1.61±0.31, and 2.72±0.52, respectively; the relative phosphorylation levels of JNK protein were 1.00±0.16, 2.21±0.42, 3.08±0.59, 1.46±0.29, and 2.04±0.37, respectively. Compared with the control group, the above indicators of the model group showed statistically significant differences; compared with the model group, the above indicators of the model+oe-SESN2 group or model+si-SESN2 group showed statistically significant differences; compared with the model+si-SESN2 group, the above indicators of the model+si-SESN2+oe-ULK1 group all showed statistically significant differences (P<0.05, P<0.01, P<0.001).

SESN2 activates ULK1, promotes JS-1 cell activation, promotes cell proliferation and invasion, and regulates cell homeostasis, possibly through the activation of JNK signaling pathway.