Enhanced Intracellular Delivery of BCG Cell Wall Skeleton into Bladder Cancer Cells Using Liposomes Functionalized with Folic Acid and Pep-1 Peptide.

Ho Yub Yoon,Gwang Yong Hwang,Chang Hyun Kim,In Ho Chang,Yoon Tae Goo,Young Wook Choi,Young Mi Whang,Hee Mang Yang

doi:10.3390/pharmaceutics11120652

Ho Yub Yoon, Gwang Yong Hwang + Show 6 more

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https://doi.org/10.3390/pharmaceutics11120652

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Abstract

Although bacillus Calmette–Guérin cell wall skeleton (BCG-CWS) might function as a potential substitute for live BCG, its use in the treatment of bladder cancer remains limited owing to issues such as insolubility and micrometer-size following exposure to an aqueous environment. Thus, to develop a novel nanoparticulate system for efficient BCG-CWS delivery, liposomal encapsulation was carried out using a modified emulsification-solvent evaporation method (targets: Size, <200 nm; encapsulation efficiency, ~60%). Further, the liposomal surface was functionalized with specific ligands, folic acid (FA), and Pep-1 peptide (Pep1), as targeting and cell-penetrating moieties, respectively. Functionalized liposomes greatly increased the intracellular uptake of BCG-CWS in the bladder cancer cell lines, 5637 and MBT2. The immunoactivity was verified through elevated cytokine production and a THP-1 migration assay. In vivo antitumor efficacy revealed that the BCG-CWS-loaded liposomes effectively inhibited tumor growth in mice bearing MBT2 tumors. Dual ligand-functionalized liposome was also superior to single ligand-functionalized liposomes. Immunohistochemistry supported the enhanced antitumor effect of BCG-CWS, with IL-6 production and CD4 infiltration. Thus, we conclude that FA- and Pep1-modified liposomes encapsulating BCG-CWS might be a good candidate for bladder cancer treatment with high target selectivity.

Highlights

Bladder cancer is the most common malignancy of the urinary tract and results from the uncontrolled growth of cells that line the bladder wall
bacillus Calmette–Guérin (BCG) cell wall skeleton (BCG-CWS), a subunit derived from BCG, is an insoluble fraction of the cell wall consisting of mycolic acids and neutral sugars such as arabinose, galactose, and peptidoglycans
The conformational features were characterized by determining the number of folic acid (FA) and Pep-1 peptide (Pep1) molecules located at the liposomal surface, based on the earlier reports [9,12,14]

Summary

Introduction

Bladder cancer is the most common malignancy of the urinary tract and results from the uncontrolled growth of cells that line the bladder wall. Bladder cancer is common in both men and women, with approximately 75% of patients presenting non-muscle invasive bladder cancer at the time of diagnosis [1]. This type of bladder cancer can be surgically treated by transurethral resection of the tumor, enabling a high survival rate (88–98%), extensive follow-up is still required as surgical resection is associated with a high recurrence rate of up to 70% [2]. BCG-CWS has been introduced as a highly effective immune activator for bladder cancer immunotherapy [5]

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