ABSTRACT
Objective:To investigate the radiosensitizing effect and underlying mechanism of STING agonist (c-di-AMP) on cutaneous melanoma cells.Methods:Human cutaneous melanoma cells (A375) were divided into four groups: the control group, 10 μmol/L c-di-AMP group, X-ray irradiation group and X-ray irradiation combined with c-di-AMP group. The radiosensitizing effect of c-di-AMP on A375 cells was detected by CCK-8-based viability assay, lactate dehydrogenase (LDH) release assay, flow cytometry-based apoptosis assay, and colony formation assay. Western blot analysis was used to determine the expressions of cell death-related proteins.Results:In combination with 10 Gy X-ray irradiation, 10 μmol/L c-di-AMP showed significant radiosensitization effect in A375 cells, which was evidenced by decreased cell activity ( t=5.11, P<0.05), increased cytotoxicity ( t=10.15, P<0.05) and cell apoptosis ( t=4.41, P<0.05) and reduced clone viability( t=6.30, 3.55, 5.45, 3.55, P<0.05). The calculated radiosensitization ratio of c-di-AMP to A375 cells was 1.88. Moreover, 10 μmol/L c-di-AMP further increased the expressions of cell death-related proteins induced by radiation in A375 cells. Conclusions:The STING agonist c-di-AMP can be used as a radiosensitizer for cutaneous melanoma, which may provide a novel strategy for radiotherapy.
ABSTRACT
Objective To detect mRNA expression of stimulator of interferon genes(STING)and type Ⅰ interferons(IFN-α and IFN-β)in peripheral blood mononuclear cells(PBMCs)of patients with chronic hepatitis B(CHB), and evaluate its correlation with hepatitis B virus load.Methods 88 untreated CHB patients(CHB group)and 74 healthy persons(control group)who performed physical examination were chosen from Renmin Hospital of Wuhan University during the same period between February 2016 and February 2017.Expressions of mRNA of STING, IFN-α, and IFN-βwere detected by quantitative real-time polymerase chain reaction(PCR), their relative expression values were obtained by 2-ΔΔCT method, results were statistically analyzed.Results The expression of STING, IFN-α, and IFN-βmRNA in peripheral blood of CHB patients were 2.95, 3.14, and2.01folds of healthy controls respectively, differences were statistically significant(t=-4.72, -3.41, -2.31, respectively, all P＜0.05).STING relative expression in patients with HBV DNA load≤104 IU/mL was 2.98, 3.76, and 3.97 folds of patients with HBV DNA load 104-105 IU/mL, 105-106 IU/mL, and＞106 IU/mL, respectively(P＜0.05).mRNA expressions of STING in CHB patients were positively correlated with that of IFN-αand IFN-βmRNA (r=0.475, 0.503, respectively, both P＜0.05).Conclusion The expression of STING increased in patients with CHB, high expression of STING impacted the replication of HBV.