Timosaponin A-III Induces ROS-mediated Apoptosis and Triggers Protective Autophagy via the AMPK/mTOR Pathway in
Jianjian Wu1,2, Juntao Li1,2, Qiang Guo1,2
1Department of Urology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510655, China.
Introduction:
Timosaponin A-III (TAIII) is an effective anti-tumor ingredient extracted from the rhizomes of Anemarrhena asphodeloides. However, the effect of TAIII on prostate cancer cells (PCa) and its underlying mechanisms is rarely investigated. The current study aimed to investigate the anti-tumor effect and potential mechanisms of TAIII in PCa cells.
Methods:
The effect of TAIII on the cell proliferation of PCa was evaluated by CCK-8 assay, colony formation assay, and EDU assay. Cell apoptosis and reactive oxygen species (ROS) production were evaluated by flow cytometry. The puncta of LC3 were detected by immunofluorescence analysis. The protein levels of apoptosis, autophagy, and AMPK/mTOR pathway were assessed by western blot. Finally, a PC3 xenograft nude mouse model was constructed to determine the effect of TAIII combined with chloroquine (CQ) in vivo.
Results:
Our data showed that TAIII inhibited the proliferation of PCa cells and induced ROS-dependent apoptosis. TAIII treatment dramatically promoted the formation of LC3-positive puncta, and increased the expression of LC3B-II and P62 protein. Moreover, the combination of TAIII with CQ significantly enhanced the pro-apoptosis effect of TAIII in PCa cells and the PC3 xenograft model. In addition, the activation of the AMPK/mTOR pathway and the induction of autophagy induced by TAIII were reversed by Compound C. Suppressing AMPK with Compound C enhanced the apoptosis induced by TAIII in PCa cells.
Discussion:
This study establishes TAIII as a potent anti-prostate-cancer agent that kills tumor cells via ROSdriven apoptosis while simultaneously triggering cytoprotective autophagy through the AMPK-mTOR axis. However, TAIII's clinical potential awaits pharmacokinetic, bioavailability, and toxicity evaluation.
Conclusion:
TAIII induced ROS-mediated cell apoptosis and promoted cytoprotective autophagy via the AMPK/mTOR pathway in PCa. These findings may provide a new strategy for combining TAIII with CQ together for PCa treatment.
Insights
Timosaponin A-III (TAIII) effectively inhibits prostate cancer (PCa) cell growth by inducing reactive oxygen species (ROS)-dependent apoptosis and activating autophagy via the AMPK/mTOR pathway. Combining TAIII with chloroquine (CQ) enhances its anti-cancer effects in vivo.
Area of Science:
- Oncology
- Pharmacology
- Cell Biology
Background:
- Timosaponin A-III (TAIII), derived from Anemarrhena asphodeloides, shows anti-tumor potential.
- Limited research exists on TAIII's effects and mechanisms in prostate cancer (PCa).
Purpose of the Study:
- To investigate the anti-tumor effects of TAIII on PCa cells.
- To elucidate the underlying mechanisms of TAIII's action in PCa.
Main Methods:
- Cell proliferation assessed via CCK-8, colony formation, and EDU assays.
- Apoptosis and reactive oxygen species (ROS) production measured by flow cytometry.
- Autophagy markers (LC3, P62) and AMPK/mTOR pathway proteins analyzed by western blot and immunofluorescence.
- In vivo efficacy evaluated using a PC3 xenograft nude mouse model, with and without chloroquine (CQ).
Main Results:
- TAIII significantly inhibited PCa cell proliferation and induced ROS-dependent apoptosis.
- TAIII treatment increased autophagosome formation (LC3 puncta) and altered LC3B-II/P62 levels.
- Combination therapy with TAIII and CQ enhanced anti-prostate cancer effects in vitro and in vivo.
- TAIII-induced autophagy activation via AMPK/mTOR was confirmed and modulated by Compound C.
Conclusions:
- TAIII exhibits potent anti-prostate cancer activity by inducing apoptosis and autophagy through the AMPK-mTOR pathway.
- TAIII's mechanism involves ROS generation, apoptosis induction, and autophagy modulation.
- Combination of TAIII with CQ presents a potential therapeutic strategy for PCa.
- Further evaluation of TAIII's pharmacokinetics, bioavailability, and toxicity is necessary for clinical application.
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