A visualizable mitochondrial-targeted Chlorambucil prodrug for enhancing anti-hepatoma efficacy
Liyuan Lin1,2, Guojun Pan1, Ying Zhi1
1Department of Clinical Pharmacy, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, School of Pharmaceutical Sciences & Institute of Materia Medical, Shandong First Medical University & Shandong Academy of Medical Sciences, School of Life Sciences, Medical Science and Technology Innovation Center, Department of Oncology, School of Clinical and Basic Medical Sciences, Jinan City, Shandong, 250117, China.
Abstract:
Mitochondria play essential roles in tumor biology, influencing apoptosis, redox homeostasis, ion balance, and genetic stability; disruptions in these processes often dictate the balance between tumor progression and suppression. Consequently, mitochondria-targeted cancer therapy has emerged as a promising strategy for improving therapeutic selectivity. Chlorambucil (CLB), a bifunctional alkylating agent, is clinically limited by its lack of tumor specificity and substantial toxicity to normal tissues, including the risk of inducing secondary malignancies. To overcome these limitations, we designed a structurally derivatized CLB prodrug-BPA-CLB that incorporates fluorescence for visualization and a mitochondrial-targeting moiety to enhance intratumoral selectivity. It was constructed by modifying the 1,8-naphthalimide scaffold to improve delocalization and lipophilicity and subsequently conjugating it to CLB. This design leverages organelle-specific distribution and real-time imaging to enable precise drug delivery at the subcellular level. Using advanced confocal imaging and LC-MS analysis, we confirmed that BPA-CLB accumulates selectively in mitochondria. In vitro and in vivo evaluations demonstrated that BPA-CLB markedly reduces toxicity to normal cells while maintaining potent antitumor activity. Mechanistically, BPA-CLB disrupts mitochondrial morphology and function, increases reactive oxygen species (ROS) production, induces apoptosis, and suppresses tumor-cell migration. This process is related to the combination of VDAC2. In conclusion, BPA-CLB provides a visually traceable and mitochondria-specific delivery strategy that minimizes off-target interactions and enhances CLB's therapeutic selectivity. By precisely perturbing mitochondrial function, BPA-CLB significantly improves antitumor efficacy against hepatocellular carcinoma, highlighting its potential as a new class of subcellularly targeted chemotherapeutics.
Insights
A novel mitochondria-targeted cancer drug, BPA-CLB, enhances chlorambucil (CLB) efficacy by selectively targeting tumor cells. This approach minimizes toxicity to healthy tissues and improves antitumor activity, particularly in hepatocellular carcinoma.
Area of Science:
- Mitochondrial biology and cancer therapeutics.
- Drug delivery and nanomedicine.
Background:
- Mitochondria are crucial in tumor progression, making them a target for cancer therapy.
- Current chemotherapy agents like chlorambucil (CLB) lack tumor specificity and cause significant toxicity.
- Developing targeted drug delivery systems can improve therapeutic selectivity and reduce side effects.
Purpose of the Study:
- To design and evaluate a novel mitochondria-targeted chlorambucil (CLB) prodrug, BPA-CLB, for enhanced cancer therapy.
- To improve the tumor specificity and reduce the toxicity of CLB through subcellular targeting.
- To visualize and confirm the selective accumulation of the prodrug in mitochondria.
Main Methods:
- Synthesis of a novel CLB prodrug (BPA-CLB) incorporating a fluorescent tag and mitochondrial-targeting moiety.
- Confocal imaging and liquid chromatography-mass spectrometry (LC-MS) to confirm mitochondrial localization.
- In vitro and in vivo studies to assess cytotoxicity, antitumor activity, and mechanism of action.
Main Results:
- BPA-CLB demonstrated selective accumulation in mitochondria.
- The prodrug significantly reduced toxicity to normal cells while maintaining potent antitumor effects.
- BPA-CLB disrupted mitochondrial morphology and function, increased reactive oxygen species (ROS), induced apoptosis, and suppressed tumor cell migration.
- The mechanism involves interaction with VDAC2.
Conclusions:
- BPA-CLB offers a visually traceable and mitochondria-specific delivery strategy for CLB.
- This approach minimizes off-target effects and enhances therapeutic selectivity.
- Targeting mitochondrial function with BPA-CLB shows significant potential for treating hepatocellular carcinoma and represents a new class of chemotherapeutics.
