A Nano Drug Delivery System Based on Angelica sinensis Polysaccharide for Combination of Chemotherapy and Immunotherapy

Abstract

Combination of chemotherapy and immunotherapy has been a promising strategy in cancer treatment. Polysaccharides from Angelica sinensis (AP), a well-known Chinese herbal medicine, have been proved to have good immunomodulatory activity. In the present study, an enzyme-sensitive tumor-targeting nano drug delivery system (AP-PP-DOX (doxorubicin), PP stood for peptide) was constructed. In this system, Angelica polysaccharides act as not only carriers to targeted delivery of drugs to tumor tissue but also effectors to improve tumor microenvironment and enhance immune function, resulting in synergistic antitumor effect with chemotherapy drugs. The structure of this conjugate was confirmed by FI-IR and ¹H-NMR. The particle size and zeta potential of the nanoparticles were 129.00 ± 3.32 nm and -28.45 ± 0.22 mV, respectively. Doxorubicin (DOX) and AP could be quickly released from the AP-PP-DOX under the presence of matrix metalloproteinase 2 (MMP2). The released DOX showed good antitumor efficacy in vitro. The treatment of released AP moiety increased the expression of IL-2, while that of IL-10 was decreased, showing potential in restoring Th1/Th2 immune balance in tumor microenvironment. In a word, this drug delivery system, with specific tissue targeting and tumor microenvironment improvement, will open a new avenue for combination treatment of cancer.

Keywords: Angelica sinensis polysaccharide; doxorubicin; enzymes sensitive drug delivery; synergistic therapy.

Figure 1

Proposed schematic diagram of AP-PP-DOX (Angelica polysaccharide-peptide-doxorubicin) nanoparticles for antitumor drug delivery.

Figure 2

Synthetic scheme of AP-PP-DOX conjugates.

Figure 3

(a) FT-IR spectrum of AP and AP-maleic anhydride (MA). (b) ¹H-NMR spectrum of AP, AP-MA, and AP-PP. (c) FT-IR spectrum of DOX, 3-(Maleimido) propionic acid N-hydroxysuccinimide ester (SMP), and DOX-SMP. (d) ¹H-NMR spectrum of AP-PP-DOX.

Figure 4

The size (a), zeta potential (b), and TEM image (c) of AP-PP-DOX nanoparticles.

Figure 5

In vitro drug release profile of the nanoparticles. The AP-PP-DOX nanoparticles were incubated with PBS (d) or matrix metalloproteinase 2 (MMP2) at 10 nM (c), 20 nM (b), and 40 nM (a). Data were expressed as the mean ± SD.

Figure 6

Cellular uptake of the nanoparticles after 2 h of incubation with the A549 cells, determined by LSCM (a) and FACS (b). a, Free DOX; b, AP-PP-DOX without MMP2 preincubation; c, AP-PP-DOX with MMP2 preincubation.

Figure 7

Cytotoxicity of AP-PP-DOX nanoparticles in cancer cells. (a) A549 (b) MCF-7. The cell viability assay was performed after 48 h with/without MMP2. Data were expressed as the mean ± SD. (n = 6, * p < 0.05, ** p < 0.01 vs. AP-PP-DOX).

Figure 8

Effect of AP moiety (AP-GPLG) on proliferation of mouse spleen cells (a), IL-2 secretion (b), and IL-10 secretion (c). Data were expressed as the mean ± SD. (n = 6 in A, n = 3 in B and C, * p <0.05, ** p < 0.01 vs. control).