The Use of a Liposomal Formulation Incorporating an Antimicrobial Peptide from Tilapia as a New Adjuvant to Epirubicin in Human Squamous Cell Carcinoma and Pluripotent Testicular Embryonic Carcinoma Cells.

Yu-Li Lo,Wei-Chen Tu,Hsin-Pin Lee

doi:10.3390/ijms160922711

Yu-Li Lo, Wei-Chen Tu + Show 1 more

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https://doi.org/10.3390/ijms160922711

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Abstract

This study aims to explore the effects and mechanisms of hepcidin, a potential antimicrobial peptide from Tilapia, and epirubicin (Epi), an antineoplastic agent, on the generation of reactive oxygen species (ROS) and link the ROS levels to the reversal mechanisms of multidrug resistance (MDR) by epirubicin and hepcidin in human squamous cell carcinoma SCC15 and human embryonal carcinoma NT2D1 cells. The cells, pretreated with hepcidin, epirubicin, or a combination of these compounds in PEGylated liposomes, were used to validate the molecular mechanisms involved in inhibiting efflux transporters and inducing apoptosis as evaluated by cytotoxicity, intracellular accumulation, mRNA levels, cell cycle distribution, and caspase activity of this combination. We found that hepcidin significantly enhanced the cytotoxicity of epirubicin in liposomes. The co-incubation of epirubicin with hepcidin in liposomes intensified the ROS production, including hydrogen peroxide and superoxide free radicals. Hepcidin significantly increased epirubicin intracellular uptake into NT2D1 and SCC15 cells, as supported by the diminished mRNA expressions of MDR1, MDR-associated protein (MRP) 1, and MRP2. Hepcidin and/or epirubicin in liposomes triggered apoptosis, as verified by the reduced mitochondrial membrane potential, increased sub-G1 phase of cell cycle, incremental populations of apoptosis using annexin V/PI assay, and chromatin condensation. As far as we know, this is the first example showing that PEGylated liposomal TH1-5 and epirubicin gives rise to cell death in human squamous carcinoma and testicular embryonic carcinoma cells through the reduced epirubicin efflux via ROS-mediated suppression of P-gp and MRPs and concomitant initiation of mitochondrial apoptosis pathway. Hence, hepcidin in PEGylated liposomes may function as an adjuvant to anticancer drugs, thus demonstrating a novel strategy for reversing MDR.

Highlights

Cationic antimicrobial peptides (AMPs) can be found from prokaryotes to humans mainly in the innate immune system [1]
PEGylated liposomal preparations with or without TH1-5 and/or Epi were well-dispersed nanoparticles with sizes ranging from 93.12 ± 5.31 nm for Lip to 108.1 ± 4.67 nm for Lip-Epi+TH1-5, with a homogeneous polydispersity index about 0.1 (Table 1)
As Epi was enclosed into liposomes, the zeta potential of Lip-Epi was marginally increased due to the cationic characteristic of Epi

Summary

Introduction

Cationic antimicrobial peptides (AMPs) can be found from prokaryotes to humans mainly in the innate immune system [1]. They demonstrate activities against diverse pathogens, including bacteria, viruses, fungi, mycoplasma, and parasites [2,3]. The fundamental mechanisms for AMP-mediated membrane collapse and tumor-specific cytotoxicity are poorly understood at present. Because of their size and cationic properties, AMPs are less vulnerable to proteolysis in serum and urine, making them prospective candidates for the treatment of intravesical tumor [6]. Cecropins A and B have exhibited good therapeutic potential for the management of invasive bladder cancer with the benefit of restricted cytotoxicity to normal cells [7]

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