Terpenes-Modified Lipid Nanosystems for Temozolomide, Improving Cytotoxicity against Glioblastoma Human Cancer Cells In Vitro

Abstract

Currently, increasing the efficiency of glioblastoma treatment is still an unsolved problem. In this study, a combination of promising approaches was proposed: (i) an application of nanotechnology approach to create a new terpene-modified lipid system (7% w/w), using soybean L-α-phosphatidylcholine, N-carbonyl-methoxypolyethylene glycol-2000)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine for delivery of the chemotherapy drug, temozolomide (TMZ, 1 mg/mL); (ii) use of TMZ associated with natural compounds-terpenes (1% w/w) abietic acid and Abies sibirica Ledeb. resin (A. sibirica). Different concentrations and combinations of terpene-lipid systems were employed to treat human cancer cell lines T 98G (glioblastoma), M-Hela (carcinoma of the cervix) and human liver cell lines (Chang liver). The terpene-lipid systems appeared to be unilamellar and of spherical shape under transmission electron microscopy (TEM). The creation of a TMZ-loaded terpene-lipid nanosystem was about 100 nm in diameter with a negative surface charge found by dynamic light scattering. The 74% encapsulation efficiency allowed the release time of TMZ to be prolonged. The modification by terpenes of TMZ-loaded lipid nanoparticles improved by four times the cytotoxicity against human cancer T 98G cells and decreased the cytotoxicity against human normal liver cells. Terpene-modified delivery lipid systems are of potential interest as a combination therapy.

Keywords: Abies sibirica Ledeb. resin; abietic acid; lipid nanoparticles; temozolomide; terpenes.

Figure 1

GC-MS chromatograms of Abies sibirica resin for identification of components using Methods A (a) and B (b).

Figure 2

TEM imaging of TMZ-loaded abietic acid (a) and A. sibirica (b) PC/DSPE–PEG₂₀₀₀/Ch lipid nanosystems, C_PC = 0.58 μg/mL, mQ water, 25 °C. Scale bar is 2 μm and 200 nm are in insert (a) and (b), respectively.

Figure 3

FTIR spectra of PC in ethanol (1, red), mixture of Ph and abietic acid in ethanol (2, olive), mixture of Ph and abietic acid and TMZ in ethanol (3, Royal blue) and ethanol (black).

Figure 4

Size distribution using intensity (a) and number (b) parameters of TMZ-loaded lipid nanosystems (1), A. sibirica–lipid nanosystems (2) and TMZ-loaded abietic acid–lipid nanosystems (3), and monitoring the stability in vitro conditions in Tris buffer (10 mM, pH = 7.4) within 24 h and human plasma within 2 h at 37 °C.

Figure 5

HPLC chromatogram showing TMZ peak at 326 nm (blue) and metabolite peak at 272 nm (red) after (a) initial; (b) 12 h; (c) 24 h in phosphate buffer (0.025 M) at pH = 7.4.

Figure 6

In vitro TMZ release, free solution (1), lipid nanosystems (2), abietic acid–lipid nanosystems (3), A. sibirica–lipid nanosystems (4) using the dialysis bag method (n = 3, experiments were replicated in triplicate), acetate buffer (0.01 M), pH = 4, 37 °C.