Curcumin suppresses proliferation of pancreatic carcinoma cells by inhibiting the STAT3 signal pathway

AIM: To investigate whether the signal transducer and activator of transcription 3 (STAT3) signal pathway is involved in the effect of curcumin on cell proliferation in pancreatic carcinoma cell line SW1990.

METHODS: SW1990 cells were incubated with different concentrations (20, 40, 60, 80, 100 mmol/L) of curcumin for different durations (0, 4, 12, 24, 48, 32 h). MTT assay was used to measure the proliferation of SW1990 cells. The protein expression of STAT3 and phosphorylated STAT3 (p-STAT3) in SW1990 cells was detected by Western blotting. Semi-quantitative RT-PCR was used to determine the mRNA expression of bcl-2, bax, survivin and bak in SW1990 cells.

RESULTS: Curcumin inhibited SW1990 cell proliferation in a time- and dose-dependent manner (P<0.05). Western blot analysis revealed that curcumin reduced the level of p-STAT3 protein expression (F = 36.157, P<0.05) in a dose-dependent manner, but had no significant impact on STAT3 level (F = 8.29, P>0.05). Moreover, curcumin inhibited mRNA expression levels of bcl-2, bak and survivin (F = 75.690, 62.301, 52.73; P<0.01, 0.01, 0.05) in a dose-dependent manner and up-regulated bax mRNA expression (F = 65.93, P<0.05).

CONCLUSION: Curcumin inhibits the proliferation of pancreatic carcinoma cells perhaps by inhibiting STAT3 phosphorylation and thereby reducing bcl-2, bak and survivin expression.