Related Experiment Video
Updated: Aug 15, 2025
Induction of Invasive Transitional Cell Bladder Carcinoma in Immune Intact Human MUC1 Transgenic Mice: A Model for Immunotherapy Development
Published on: October 30, 2013
Hispolon Methyl Ether, a Hispolon Analog, Suppresses the SRC/STAT3/Survivin Signaling Axis to Induce Cytotoxicity in
Min-Yung Kuo1,2, Wei-Ting Yang3, Yann-Jen Ho3
1Pediatric Surgery Division, Department of Surgery, Tungs' Taichung MetroHarbor Hospital, Taichung 402202, Taiwan.
Abstract:
Bladder cancer is a leading human malignancy worldwide. Signal transducer and activator of transcription (STAT) 3 is an oncogenic transcription factor commonly hyperactivated in most human cancers, including bladder cancer. Notably, preclinical evidence has validated STAT3 blockade as a promising therapeutic strategy for bladder cancer. Hispolon Methyl Ether (HME) is a structural analog of hispolon, an anticancer component of the medicinal mushroom Phellinus linteus. Thus far, HME's anticancer activity and mechanisms remain largely unknown. We herein report HME was cytotoxic, more potent than cisplatin, and proapoptotic to various human bladder transitional carcinoma cell lines. Of note, HME blocked STAT3 activation, evidenced by HME-elicited reduction in tyrosine 705-phosphorylated STAT3 levels constitutively expressed or induced by interleukin-6. Significantly, HME-induced cytotoxicity was abrogated in cells expressing a dominant-active STAT3 mutant (STAT3-C), confirming STAT3 blockage as a pivotal mechanism of HME's cytotoxic action. We further revealed that survivin was downregulated by HME, while its levels were rescued in STAT3-C-expressing cells. Moreover, survivin overexpression abolished HME-induced cytotoxicity, illustrating survivin as a central downstream mediator of STAT3 targeted by HME. Lastly, HME was shown to lower tyrosine 416-phosphorylated SRC levels, suggesting that HME inhibits STAT3 by repressing the activation of SRC, a STAT3 upstream kinase. In conclusion, we present the first evidence of HME's anti-bladder cancer effect, likely proceeding by evoking apoptosis through suppression of the antiapoptotic SRC/STAT3/survivin signaling axis.
Insights
Hispolon Methyl Ether (HME) effectively combats bladder cancer by inducing apoptosis. This compound blocks Signal Transducer and Activator of Transcription 3 (STAT3) activation, a key factor in cancer growth, offering a promising new therapeutic avenue.
Area of Science:
- Oncology
- Pharmacology
- Molecular Biology
Background:
- Bladder cancer is a significant global health concern.
- Signal transducer and activator of transcription 3 (STAT3) is frequently hyperactivated in bladder cancer, presenting a therapeutic target.
- Hispolon Methyl Ether (HME), derived from *Phellinus linteus*, is a potential anticancer agent with largely unknown mechanisms.
Purpose of the Study:
- To investigate the anticancer activity of HME against human bladder transitional carcinoma cells.
- To elucidate the molecular mechanisms underlying HME's cytotoxic effects, focusing on STAT3 signaling.
Main Methods:
- Cytotoxicity assays were performed on human bladder transitional carcinoma cell lines treated with HME and cisplatin.
- STAT3 activation was assessed by measuring phosphorylated STAT3 (p-STAT3) levels.
- The role of STAT3 in HME's action was confirmed using cells expressing a dominant-active STAT3 mutant (STAT3-C).
- Downstream targets, including survivin and SRC kinase, were analyzed.
Main Results:
- HME demonstrated potent cytotoxic and proapoptotic effects on bladder cancer cell lines, exceeding cisplatin's efficacy.
- HME significantly inhibited STAT3 activation, evidenced by reduced p-STAT3 levels.
- HME-induced cytotoxicity was dependent on STAT3 inhibition, as it was abrogated in STAT3-C expressing cells.
- HME downregulated survivin expression and inhibited SRC kinase activation, key components of the SRC/STAT3/survivin axis.
Conclusions:
- HME exhibits significant anti-bladder cancer activity through the induction of apoptosis.
- HME exerts its effects by suppressing the antiapoptotic SRC/STAT3/survivin signaling pathway.
- HME represents a promising novel therapeutic agent for bladder cancer treatment.
