Liposome-Encapsulated Bacillus Calmette-Guérin Cell Wall Skeleton Enhances Antitumor Efficiency for Bladder Cancer In Vitro and In Vivo via Induction of AMP-Activated Protein Kinase

• Published in: Cancers 2020-12, Vol.12 (12), p.3679
• Main Authors: Whang, Young Mi, Yoon, Da Hyeon, Hwang, Gwang Yong, Yoon, Hoyub, Park, Serk In, Choi, Young Wook, Chang, In Ho
• Format: Article
• Language: English
• Subjects: AMP; AMP-activated protein kinase; Antitumor activity; Apoptosis; Autophagy; Bacillus; Bacillus Calmette-Guerin vaccine; BCG; Bladder cancer; c-Jun protein; Cell growth; Cell proliferation; Cell walls; Colorectal cancer; Dichloromethane; Efficiency; Endocytosis; Endoplasmic reticulum; Immunotherapy; Internalization; JNK protein; Kinases; Liposomes; Nanoparticles; Phosphorylation; Rapamycin; Reactive oxygen species; TOR protein; Transcription factors; Urothelial carcinoma
• ISSN: 2072-6694; 2072-6694
• DOI: 10.3390/cancers12123679

The Bacillus Calmette-Guérin cell wall skeleton (BCG-CWS), the main immune active center of BCG, is a potent candidate non-infectious immunotherapeutic drug and an alternative to live BCG for use against urothelial carcinoma. However, its application in anticancer therapy is limited, as BCG-CWS tends to aggregate in both aqueous and non-aqueous solvents. To improve the internalization of BCG-CWS into bladder cancer cells without aggregation, BCG-CWS was nanoparticulated at a 180 nm size in methylene chloride and subsequently encapsulated with conventional liposomes (CWS-Nano-CL) using an emulsified lipid (LEEL) method. In vitro cell proliferation assays showed that CWS-Nano-CL was more effective at suppressing bladder cancer cell growth compared to nonenveloped BCG-CWS. In an orthotopic implantation model of luciferase-tagged MBT2 bladder cancer cells, encapsulated BCG-CWS nanoparticles could enhance the delivery of BCG-CWS into the bladder and suppress tumor growth. Treatment with CWS-Nano-CL induced the inhibition of the mammalian target of rapamycin (mTOR) pathway and the activation of AMP-activated protein kinase (AMPK) phosphorylation, leading to apoptosis, both in vitro and in vivo. Furthermore, the antitumor activity of CWS-Nano-CL was mediated predominantly by reactive oxygen species (ROS) generation and AMPK activation, which induced endoplasmic reticulum (ER) stress, followed by c-Jun N-terminal kinase (JNK) signaling-mediated apoptosis. Therefore, our data suggest that the intravesical instillation of liposome-encapsulated BCG-CWS nanoparticles can facilitate BCG-CW cellular endocytosis and provide a promising drug-delivery system as a therapeutic strategy for BCG-mediated bladder cancer treatment.