Synergistic apoptotic effects of apigenin TPGS liposomes and tyroservatide: implications for effective treatment of lung cancer

Abstract

To develop an alternative treatment for lung cancer, a combination of two potent chemotherapeutic agents - liposomal apigenin and tyroservatide - was developed. The therapeutic potential of this combination was investigated using A549 cells. Apigenin and tocopherol derivative-containing D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) liposomes might improve the delivery of apigenin to tumor cells, both in vitro and in vivo. Importantly, compared to either agent alone, the combination of apigenin TPGS liposomes and tyroservatide exhibited superior cytotoxicity, induced stronger G2 arrest, and suppressed A549 cancer cell invasion at a lower dose. The proapoptotic synergistic effects were also observed in A549 cells using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, flow cytometry, and Western blot analysis. More importantly, in vivo results showed that the combination of apigenin TPGS liposomes and tyroservatide exhibited tumor-growth inhibitory effects in A549 cell-bearing mice. In conclusion, our study showed that this combination therapy could serve as a promising synergistic therapeutic approach to improve outcomes in patients with lung cancer.

Keywords: TPGS liposomes; apigenin; apoptosis; synergistic antitumor; tyroservatide.

Figure 1

The average size (A), zeta potential (B), and morphology (C) of apigenin-loaded TPGS liposomes (n=3). Abbreviation: TPGS, D-alpha-tocopheryl polyethylene glycol 1000 succinate.

Figure 2

Cellular uptake (A), intracellular distribution (B), and in vivo imaging (C) of TPGS liposomes (n=3). Abbreviation: TPGS, D-alpha-tocopheryl polyethylene glycol 1000 succinate.

Figure 3

MTT assay of apigenin (A), YSV (B) monotherapy, and a Chou–Talalay plot of the combination effect (C) in A549 cells (n=5). Abbreviations: CI, cooperativity index; Fa, fraction affected.

Figure 4

Synergistic effects of apigenin-loaded TPGS liposomes and YSV on cell cycle (A) and invasion (B) in A549 cells (n=3). Abbreviation: TPGS, D-alpha-tocopheryl polyethylene glycol 1000 succinate.

Figure 5

TUNEL (A), Annexin V-FITC apoptosis detection (B), and Western blot analysis (C) of apigenin-loaded TPGS liposomes and YSV in vitro in A549 cells (n=3). Abbreviations: FITC, fluorescein isothiocyanate; TPGS, D-alpha-tocopheryl polyethylene glycol 1000 succinate.

Figure 6

Curves of tumor volumes (A), morphology (B), and typical H&E-stained images (C) (‘N’ represents necrosis area, ‘T’ represents tumor mass) on day 15 after injection of the indicated formulations into the tail vein (n=5).

Figure 6

Curves of tumor volumes (A), morphology (B), and typical H&E-stained images (C) (‘N’ represents necrosis area, ‘T’ represents tumor mass) on day 15 after injection of the indicated formulations into the tail vein (n=5).