Signal transducer and activators of transcription 3 regulates cryptotanshinone‑induced apoptosis in human mucoepidermoid carcinoma cells

Background: Cryptotanshinone (CT) is a biologically active compound from the root of Salvia miltiorrhiza that has been reported to induce apoptosis in various cancer cell lines; but, it has not yet been fully explored in human mucoepidermoid carcinoma (MEC). Objective: Here, we demonstrated the apoptotic effects and its related mechanism in MC‑3 and YD‑15 human MEC cell lines. Materials and Methods: The effects of CT on apoptotic activity were evaluated by cell proliferation assay, Western blotting, 4’‑6‑diamidino‑2‑phenylindole staining, reverse transcription‑polymerase chain reaction, and luciferase assay. Results: Our data show that CT treatment of MC‑3 cells results in anti‑proliferative and apoptotic activities in MC‑3 and it is accompanied by a decrease in phosphorylation and dimerization of signal transducer and activators of transcription 3 (STAT3). CT decreased the expression levels of myeloid cell leukemia‑1 (Mcl‑1) and surviving, whereas Bcl‑xL expression was not changed. CT clearly regulates survivin protein at a transcriptional level and alters Mcl‑1 through proteasome‑dependent protein degradation. In addition, CT‑induced apoptotic cell death in YD‑15, another human MEC cell line, was associated with the inhibition of STAT3 phosphorylation. Conclusion: These data suggest that CT could be a good apoptotic inducer through modification of STAT3 signaling in human MEC cell lines.