Arginine, glycine, aspartic acid peptide-modified paclitaxel and curcumin co-loaded liposome for the treatment of lung cancer: in vitro/vivo evaluation

Abstract

Purpose: In this study, a novel arginine, glycine, aspartic acid peptide (RGD)-modified paclitaxel and curcumin co-loaded liposomes were developed to evaluate their antitumor activity in vitro and in vivo.

Materials and methods: Co-loaded liposomes were prepared using the solvent evaporation method. The particles had spherical shapes under electron microscopy with sizes <130 nm.

Results: By comparison with the free drug, RGD-modified paclitaxel and curcumin co-loaded liposomes and paclitaxel and curcumin co-loaded liposomes have sustained-release properties in vitro. In vivo, there was no significant difference in pharmacokinetic parameters between the RGD-modified paclitaxel and curcumin co-loaded liposomes and paclitaxel and curcumin co-loaded liposomes. A strong green fluorescence was observed in the cytoplasmic region after incubation of RGD-modified paclitaxel and curcumin co-loaded liposomes for 2 h. RGD-modified paclitaxel and curcumin co-loaded liposomes showed a superior antiproliferative effect on A549 cells with a possible mechanism that suppressed the multidrug resistance phenomenon and exhibited a clear synergistic effect.

Conclusion: The results indicate that RGD-modified paclitaxel and curcumin co-loaded liposomes had a better antitumor effect in vivo than the non-modified LPs. These results indicate that RGD-modified co-loaded liposomes are a promising candidate for antitumor drug delivery.

Keywords: arginine; aspartic acid peptide; cell uptake; curcumin; cytotoxicity study; glycine; in vivo anti-tumor study; liposome; paclitaxel.

Figure 1

The microstructural schematic diagram of RGD-PTX-CUR LPs. Abbreviations: DSPE-PEG, distearoyl-l-a-phosphatidylethanolamine; PTX, paclitaxel; CUR, curcumin; LPs, liposomes; RGD, arginine, glycine, aspartic acid peptide.

Figure 2

Transmission electron microscope photograph of PTX and CUR co-loaded LPs. Note: (A) Not RGD modified, (B) RGD modified (magnification ×97,000). Abbreviations: PTX, paclitaxel; CUR, curcumin; LPs, liposomes; RGD, arginine, glycine, aspartic acid peptide.

Figure 3

The release profile of free PTX, free CUR, PTX-CUR LPs and RGD-PTX-CUR LPs from release medium (50%, v/v, of ethanol) at 37°C in a shaking water bath at 75 rpm (n=6). Abbreviations: PTX, paclitaxel; CUR, curcumin; LPs, liposomes; RGD, arginine, glycine, aspartic acid peptide.

Figure 4

Plasma concentration-time profiles. Note: (A) PTX and (B) CUR after iv administration of different formulations to rats (n=10). Abbreviations: PTX, paclitaxel; CUR, curcumin; LPs, liposomes; RGD, arginine, glycine, aspartic acid peptide.

Figure 5

Confocal images of cellular uptake. Notes: (A) Free PTX/CUR, (B) PTX/CUR LPs, and (C) RGD-PTX/CUR LPs by 549 cells. Incubation time was 2 h. Abbreviations: PTX, paclitaxel; CUR, curcumin; LPs, liposomes; RGD, arginine, glycine, aspartic acid peptide.

Figure 6

In vitro cytotoxicity analysis of free PTX/CUR, PTX/CUR LPs and RGD-PTX/CUR LPs on A549 cell lines. Notes: (A) 24 hours, or (B) 48 hours. Cell viability assay was performed by MTT assay. *p<0.05 RGD-PTX/CUR LPs vs PTX/CUR LPs. Abbreviations: PTX, paclitaxel; CUR, curcumin; LPs, liposomes; RGD, arginine, glycine, aspartic acid peptide.

Figure 7

The tumor volume in nude mice transplanted with a human adenocarcinoma (A549) cell line on day 16. Note: (A) Control group, (B) free PTX/CUR, (C) PTX/CUR LPs and (D) RGD-PTX/CUR LPs. Abbreviations: PTX, paclitaxel; CUR, curcumin; LPs, liposomes; RGD, arginine, glycine, aspartic acid peptide.