To investigate the effects and mechanism of naringenin inhibiting the non-receptor tyrosine kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway on the proliferation and apoptosis of esophageal cancer cells.

The effects of different doses of naringenin on KYSE150 cell viability was screened using cell counting kit-8 (CCK-8), and naringenin concentration was selected. KYSE150 cells were sequentially divided into control group (conventional culture), low-dose experimental group (10 μmol·L^-1 naringenin), high-dose experimental group (40 μmol·L^-1 naringenin), JAK2/STAT3 pathway inhibitor group (20 μmol·L^-1 AG490) and JAK2/STAT3 pathway activator group (40 μmol·L^-1 naringenin and 10 μmol·L^-1 coumermycin A1). The 5-bromo-2 ’- deoxyuridine (Brdu) positive cell rate was detected using the Brdu staining method, the number of cell clones formed was detected using the clone formation assay, the expression of proliferation and apoptosis related genes was detected using reverse transcription real-time fluorescence quantitative polymerase chain reaction (RT-qPCR), the apoptosis rate was detected using flow cytometry, the terminal deoxynucleotide transferase mediated 2’-deoxyuridine-5’- triphosphate notch end labeling (TUNEL) positive rate was detected using the TUNEL staining method, the expression of JAK2/STAT3 pathway related proteins was detected using Western blot, and the effect of naringenin on the growth of KYSE150 xenograft tumors Ki-67 nuclear antigen (Ki67) and tumor tissues growth in nude mice was detected using immunohistochemistry.

The half maximal inhibitory concentration of naringenin on KYSE150 cell viability is close to 40 μmol·L^-1. The Brdu positivity rates of KYSE150 cells in control group, low-dose experimental group, high-dose experimental group, JAK2/STAT3 pathway inhibitor group and JAK2/STAT3 pathway activator group were (58.64±5.23)%, (46.23±4.05)%, (21.05±3.04)%, (23.62±3.15)% and (35.98±3.21)%, respectively; the clone formation numbers were (102.36±10.25), (78.64±7.21), (50.05±4.32), (52.39±5.03) and (61.55±5.12) cells, respectively; the relative expression levels of CyclinB1 messenger ribonucleic aeid (mRNA) were 1.02±0.11, 0.74±0.05, 0.45±0.04, 0.48±0.05 and 0.62±0.06, respectively; the relative expression levels of cyclin dependent kinase 1 (CDK1) mRNA were 1.03±0.07, 0.62±0.05, 0.27±0.03, 0.30±0.04 and 0.51±0.04, respectively; the apoptosis rates were (4.15±0.42)%, (15.62±1.02)%, (29.65±2.03)%, (27.84±1.98)% and (19.66±1.20)%, respectively; the positive rates of TUNEL were (8.65±0.82)%, (20.64±2.03)%, (37.68±3.05)%, (35.62±2.16)% and (28.14±2.01)%, respectively; the relative expression levels of Bcl-xl mRNA were 1.02±0.07, 0.72±0.06, 0.41±0.04, 0.44±0.05 and 0.59±0.05, respectively; the relative expression levels of Bcl-2 mRNA were 1.01±0.05, 0.59±0.04, 0.36±0.03, 0.39±0.04 and 0.50±0.03, respectively. Compared control group with low-dose experimental group, high-dose experimental group and JAK2/STAT3 pathway inhibitor group, compared low-dose experimental group with high-dose experimental group and JAK2/STAT3 pathway inhibitor group, compared high-dose experimental group with JAK2/STAT3 pathway activator group, the above indicators all showed statistically significant differences (all P<0.05). In nude mouse experiments, the tumor volumes of animal control group, animal low-dose experimental group and animal high-dose experimental group were (1 287.65±98.54), (821.22±71.65) and (425.39±37.69) mm³, respectively; the tumor masses were (1.85±0.12), (1.20±0.09) and (0.73±0.05) g, respectively; the Ki67 positivity rates in tumor tissues were (69.52±5.36)%, (44.35±3.12)% and (20.06±2.85)%, respectively. The above indicators of the animal low and high-dose experimental groups were statistically significantly different from those of animal control group, and the above indicators of the animal high-dose experimental group were statistically significantly different from those of animal low-dose experimental group (all P<0.05).

Naringenin clearly inhibits the proliferation and promotes apoptosis of esophageal cancer KYSE150 cells by suppressing the JAK2/STAT3 signaling pathway.