Combination Chemotherapy with Cisplatin and Chloroquine: Effect of Encapsulation in Micelles Formed by Self-Assembling Hybrid Dendritic-Linear-Dendritic Block Copolymers.

Rebeca González-Pastor,Violeta Morcuende-Ventura,Teresa Sierra,Alexandre Lancelot,Pilar Martin-Duque,José L Serrano,María San Anselmo

doi:10.3390/ijms22105223

Abstract

Clinical outcomes of conventional drug combinations are not ideal due to high toxicity to healthy tissues. Cisplatin (CDDP) is the standard component for many cancer treatments, yet its principal dose-limiting side effect is nephrotoxicity. Thus, CDDP is commonly used in combination with other drugs, such as the autophagy inhibitor chloroquine (CQ), to enhance tumor cell killing efficacy and prevent the development of chemoresistance. In addition, nanocarrier-based drug delivery systems can overcome chemotherapy limitations, decreasing side effects and increasing tumor accumulation. The aim of this study was to evaluate the toxicity of CQ and CDDP against tumor and non-tumor cells when used in a combined treatment. For this purpose, two types of micelles based on Pluronic® F127 hybrid dendritic–linear–dendritic block copolymers (HDLDBCs) modified with polyester or poly(esteramide) dendrons derived from 2,2′-bis(hydroxymethyl)propionic acid (HDLDBC-bMPA) or 2,2′-bis(glycyloxymethyl)propionic acid (HDLDBC-bGMPA) were explored as delivery nanocarriers. Our results indicated that the combined treatment with HDLDBC-bMPA(CQ) or HDLDBC-bGMPA(CQ) and CDDP increased cytotoxicity in tumor cells compared to the single treatment with CDDP. Encapsulations demonstrated less short-term cytotoxicity individually or when used in combination compared to the free drugs. However, and more importantly, a low degree of cytotoxicity against non-tumor cells was maintained, even when drugs were given simultaneously.

Highlights

Combination chemotherapy has emerged as a more superior approach for cancer treatment than single-drug therapy, being able to achieve additive, potentiation or synergistic therapeutic effect and to overcome drug resistance [1,2]
Nanocarriers allow the co-delivery of multiple therapeutics to the same site, limiting the variability in the biodistribution and dosage of each drug compared with the administration of two separate treatments [36,37,38,39,40]. Based on these considerations and the excellent results achieved with Pluronic® F-127 and chemotherapeutics in previous studies [41,42], in this work, we used two dendritic–linear–dendritic hybrid block copolymers (HDLDBCs) based on Pluronic® F-127, which was functionalized at both termini with bis-MPA (2,2 -bis(hydromethyl)propionic acid) (HDLDBC-bMPA) or bis-GMPA (2,2 -bis(glycyloxymethyl)propionic acid) dendrons (HDLDBC-bGMPA) as drug encapsulation carriers for combination chemotherapy with CDDP and CQ (Figure 1)
MPA(CDDP) growethreintwhiobitoionthirneeA-f5o4ld9 cheilglshefor lilnowHeedlaa cseimllsilanr dpaattelrena,stCtCw5o0-fvoallduehsigwheerrein A549 cells higher (Table c3o),mwpiathrecdetllopthroelivfaelruaetisoonbdtaeicnredaswinigthafrtere 4C8D–7D2Ph(Ttraebaltem3e).nt with 10 μM of free CQ or 50 μM oTfhHesDeLrDesBuClt-sbMinPdAic(aCteQt)hoart HenDcLapDsBuCla-btiGonMoPfAC(CQQa)n. d CDDP in hybrid dendritic–linear–dendritic block copolymers (HDLDBCs)-bMPA or HDLDBC-bGMPA decreased cytotoxicity against HeLa and A549 cells, and the CC50 values were higher compared to the values of the free drugs

Summary

Introduction

Combination chemotherapy has emerged as a more superior approach for cancer treatment than single-drug therapy, being able to achieve additive, potentiation or synergistic therapeutic effect and to overcome drug resistance [1,2]. Nanocarriers allow the co-delivery of multiple therapeutics to the same site, limiting the variability in the biodistribution and dosage of each drug compared with the administration of two separate treatments [36,37,38,39,40] Based on these considerations and the excellent results achieved with Pluronic® F-127 and chemotherapeutics in previous studies [41,42], in this work, we used two dendritic–linear–dendritic hybrid block copolymers (HDLDBCs) based on Pluronic® F-127, which was functionalized at both termini with bis-MPA (2,2 -bis(hydromethyl)propionic acid) (HDLDBC-bMPA) or bis-GMPA (2,2 -bis(glycyloxymethyl)propionic acid) dendrons (HDLDBC-bGMPA) as drug encapsulation carriers for combination chemotherapy with CDDP and CQ (Figure 1). We show promising results in terms of the reduction in side-effects of the combination treatment with CQ encapsulated in HDLDBC-bMPA or HDLDBC-bGMPA and free CDDP compared to the treatment with free CQ and free CDDP, based on the cytotoxicity against tumor cells and high degree of biocompatibility towards non-tumor cells

Results

Cell Internalization of HDLDBC Micelles

Reagents

Cell Lines and Cell Culture

Cell Viability Determination Based on Proliferation Assay and Flow Cytometry

Statistical Analysis