Inhalation treatment of primary lung cancer using liposomal curcumin dry powder inhalers

Abstract

Lung cancer is the leading cause of cancer-related deaths. Traditional chemotherapy causes serious toxicity due to the wide bodily distribution of these drugs. Curcumin is a potential anticancer agent but its low water solubility, poor bioavailability and rapid metabolism significantly limits clinical applications. Here we developed a liposomal curcumin dry powder inhaler (LCD) for inhalation treatment of primary lung cancer. LCDs were obtained from curcumin liposomes after freeze-drying. The LCDs had a mass mean aerodynamic diameter of 5.81 μm and a fine particle fraction of 46.71%, suitable for pulmonary delivery. The uptake of curcumin liposomes by human lung cancer A549 cells was markedly greater and faster than that of free curcumin. The high cytotoxicity on A549 cells and the low cytotoxicity of curcumin liposomes on normal human bronchial BEAS-2B epithelial cells yielded a high selection index partly due to increased cell apoptosis. Curcumin powders, LCDs and gemcitabine were directly sprayed into the lungs of rats with lung cancer through the trachea. LCDs showed higher anticancer effects than the other two medications with regard to pathology and the expression of many cancer-related markers including VEGF, malondialdehyde, TNF-α, caspase-3 and BCL-2. LCDs are a promising medication for inhalation treatment of lung cancer with high therapeutic efficiency.

Keywords: BALF, lung bronchoalveolar lavage fluids; CP, curcumin powder; Curcumin; DMSO, dimethyl sulphoxide; DPI, dry powder inhaler; Dry powder inhaler; FPF, fine particle fraction; H&E, hematoxylin and eosin; HPLC, high performance liquid chromatography; LCD, liposomal curcumin dry powder inhaler; Liposome; MDA, malondialdehyde; MMAD, mass mean aerodynamic diameter; NSCLC, non-small cell lung cancer; Primary lung cancer; Pulmonary delivery; SEM, scanning electron microscopy; TEM, scanning electron microscopy; TNF-α, tumor necrosis factor-α; VEGF, vascular endothelial growth factor.

Graphical abstract

Figure 1

Appearances and morphologies of inhaled powders and curcumin liposomes. Appearances of curcumin liposomes (A) and LCDs (B). SEM images of CPs (C) and LCDs (D). TEM images of the initial curcumin liposomes (E) and the curcumin liposomes rehydrated from LCDs (F).

Figure 2

Viabilities of A549 (A, B) and BEAS-2B (C) cells after treatment with curcumin, curcumin liposomes and gemcitabine (n=4), and selection indexes (D) of these regimens. ^*P<0.05; ^**P<0.01.

Figure 3

CLSM images of the A549 cells incubated with CPs (A) and LCDs (B) at different incubation times. The scale bar indicates 25 μm.

Figure 4

Images of Hoechst-stained A549 cells after treatment with CPs (A) and LCDs (B), and flow cytometric graphs (C). The scale bar indicates 100 μm.

Figure 5

Appearances of lungs, and images of lung tissue sections (400 ×) and VEGF expression (400 ×) from the healthy rats (a); the lung cancer rats (b); the lung cancer rats treated with CPs (c); the lung cancer rats treated with LCDs (d); and the lung cancer rats treated with gemcitabine (e). The scale bars indicate 100 μm.

Figure 6

Effects of the medications on the oxidation indicator (MDA, A) pro-inflammatory cytokine (TNF-α, B), and apoptosis (caspase-3, C; BCL-2, D) (n=6). ^*P<0.05; ^**P<0.01. Protein expression by Western blot (BCL-2, pro-caspase3 and TNF-α, E). The meanings of (a)–(e) are described in Fig. 5.