Tung Min-Che, Chang Ge-Man, Dai Wen-Chyi, Hsu Chen-Hsuan, Chang Hsiang-Chun, Yang Wei-Ting, Ho Yann-Jen, Lu Chien-Hsing, Chen Yi-Hsin, Chang Chia-Che
Division of Urology, Department of Surgery, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan.
Graduate Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan.
Environ Toxicol. 2025 Apr;40(4):624-635. doi: 10.1002/tox.24446. Epub 2024 Nov 27.
Bladder cancer is one of the most common human malignancies worldwide. Aberrant activation of signal transducer and activator of transcription 3 (STAT3) is crucial to driving malignant progression and predicting poor prognosis of multiple human cancers, including bladder cancer, making STAT3 a promising target of cancer therapeutics. Cryptotanshinone (CTS) is an anticancer ingredient of Danshen ( Salvia miltiorrhiza ), a top-graded Chinese medicinal herb. However, whether CTS targets STAT3 to exert its cytotoxic effect on human bladder cancer remains unknown. Herein, we demonstrated that CTS is cytotoxic to multiple human urinary bladder transitional cell carcinoma (TCC) cell lines while sparing normal human urothelial cells. CTS provoked apoptosis-dependent bladder TCC cytotoxicity, as apoptosis blockage by z-VAD-fmk markedly rescued the clonogenicity of CTS-treated cells. Besides, CTS was found to suppress constitutive and interleukin 6-inducible activation of STAT3, evidenced by the downregulation of STAT3 tyrosine 705 phosphorylation and BCL2, a recognized STAT3 transcriptional target. Notably, ectopic expression of a dominant-active STAT3 mutant (STAT3-C) or BCL-2 alleviated CTS-induced apoptosis and clonogenicity inhibition, thus confirming STAT3 blockade as a pivotal mechanism of CTS's cytotoxic action on bladder TCC cells. Lastly, immunoblotting revealed that CTS lowered the levels of active JAK2, an upstream kinase that mediates STAT3 tyrosine 705 phosphorylation. Altogether, we conclude that the blockade of the JAK2/STAT3/BCL-2 antiapoptotic signaling axis is a vital mechanism whereby CTS provokes bladder cancer cytotoxicity. The current evidence implicates CTS's potential to be translated into a bladder cancer therapeutic agent.
膀胱癌是全球最常见的人类恶性肿瘤之一。信号转导和转录激活因子3（STAT3）的异常激活对于推动多种人类癌症（包括膀胱癌）的恶性进展和预测不良预后至关重要，这使得STAT3成为有前景的癌症治疗靶点。隐丹参酮（CTS）是顶级中药材丹参（Salvia miltiorrhiza）的一种抗癌成分。然而，CTS是否靶向STAT3以对人膀胱癌发挥其细胞毒性作用仍不清楚。在此，我们证明CTS对多种人膀胱移行细胞癌（TCC）细胞系具有细胞毒性，而对正常人尿路上皮细胞无损害。CTS引发依赖凋亡的膀胱TCC细胞毒性，因为z-VAD-fmk对凋亡的阻断显著挽救了CTS处理细胞的克隆形成能力。此外，发现CTS可抑制STAT3的组成性激活以及白细胞介素6诱导的激活，STAT3酪氨酸705磷酸化和公认的STAT3转录靶标BCL2的下调证明了这一点。值得注意的是，显性活性STAT3突变体（STAT3-C）或BCL-2的异位表达减轻了CTS诱导的凋亡和克隆形成抑制，从而证实STAT3阻断是CTS对膀胱TCC细胞发挥细胞毒性作用的关键机制。最后，免疫印迹显示CTS降低了活性JAK2的水平，JAK2是介导STAT3酪氨酸705磷酸化的上游激酶。总之，我们得出结论，JAK2/STAT3/BCL-2抗凋亡信号轴的阻断是CTS引发膀胱癌毒性的重要机制。目前的证据表明CTS有潜力转化为膀胱癌治疗药物。
