Versatile ginsenoside Rg3 liposomes inhibit tumor metastasis by capturing circulating tumor cells and destroying metastatic niches

Abstract

Limited circulating tumor cells (CTCs) capturing efficiency and lack of regulation capability on CTC-supportive metastatic niches (MNs) are two main obstacles hampering the clinical translation of conventional liposomes for the treatment of metastatic breast cancers. Traditional delivery strategies, such as ligand modification and immune modulator co-encapsulation for nanocarriers, are inefficient and laborious. Here, a multifunctional Rg3 liposome loading with docetaxel (Rg3-Lp/DTX) was developed, in which Rg3 was proved to intersperse in the phospholipid bilayer and exposed its glycosyl on the liposome surface. Therefore, it exhibited much higher CTC-capturing efficiency via interaction with glucose transporter 1 (Glut1) overexpressed on CTCs. After reaching the lungs with CTCs, Rg3 inhibited the formation of MNs by reversing the immunosuppressive microenvironment. Together, Rg3-Lp/DTX exhibited excellent metastasis inhibition capacity by CTC (“seeds”) neutralization and MN (“soil”) inhibition. The strategy has great clinical translation prospects for antimetastasis treatment with enhanced therapeutic efficacy and simple preparation process.

Targeting therapy and tumor microenvironment remodeling of triple-negative breast cancer by ginsenoside Rg3 based liposomes

“…The fluorescence intensity ratio of pyrene I1/I3 can reflect the polarity of the environment, which is related to the arrangement of acyl groups. 32 A decrease in I1/I3 value implies a higher binding affinity between the membrane regulator and the phospholipid molecules, resulting in lower micro-polarity between the lipid bilayers. The tight connection is favorable for improving the membrane stability and encapsulation efficiency of hydrophobic drugs.…”

“…Immunofluorescence staining of α-SMA 1 × 10 5 3T3 cells were incubated in a 6-well plate per well and treated overnight with TGF-β (20 ng/ml), TGF-β (20 ng/ml) plus SB-431542 (MCE, USA), a kind of TGFβ inhibitor, different 4T1 cultured medium after treatment with PBS (4T1-CM), DTX (4T1-CM@DTX), C-Lp/ DTX (4T1-CM@C-Lp/DTX), Nanoxel-PM (4T1-CM@ Nanoxel-PM), Rg3 (4T1-CM@Rg3), Rg3-Lp (4T1-CM@ Rg3-Lp), Rg3/DTX (4T1-CM@Rg3/DTX) or Rg3-Lp/ DTX (4T1-CM@Rg3-Lp/DTX) (DTX concentration, 0.5 μg/mL), respectively. 4T1-conditioned medium after different treatment was obtained for Enzyme-linked immunosorbent assay (ELISA assay) after 24 h. The 3T3 cells after different treatment were then IF stained and imaged with primary anti-α-SMA (ab124964, Abcam) and Cy3-labeled fluorescent secondary antibody (33108ES60, Yeasen) according to the procedure as described before [32].…”

“…3T3 cells were incubated in a 6-well plate at a density of 1 × 10 5 cells per well and treated overnight with TGFβ (20 ng/ml), TGF-β (20 ng/ml) plus SB-431542 (MCE, USA), a kind of TGF-β inhibitor, different 4T1 cultured medium after treatment with PBS (4T1-CM), DTX (4T1@DTX), C-Lp/DTX (4T1@C-Lp/DTX), Nanoxel-PM (4T1@Nanoxel-PM), Rg3 (4T1@Rg3), Rg3-Lp (4T1@ Rg3-Lp), Rg3/DTX (4T1@Rg3/DTX) or Rg3-Lp/DTX (4T1@Rg3-Lp/DTX) (DTX 0.5 μg/mL). The protein of the cells was then harvested according to the procedures described previously [32]. 50 mg of protein per lane were loaded on the polyacrylamide gel and then transferred onto a PVDF membrane.…”

“…Total RNAs were extracted with Trizol from tumor tissues obtained following the protocol of Quantification of tumorinfiltrating lymphocyte. Quantitative real-time PCR analysis were performed according to the procedures described before [32]. The mouse α-SMA primer pairs were 5′-ACA CGG CAT CAT CAC CAA CTG -3′ and 5′-TTG GCC TTA GGG TTC AGT GGT GTC -3′, The mouse GAPDH primer pairs were 5'-CCT CGT CCC GTA GAC AAA ATG-3′ and 5′-TGA GGT CAA TGA AGG GGT CGT-3′.…”

“…As a cholesterol analogue, it has the potential as a liposomal membrane stabilizer [29,31]. Simultaneously, its glycosyls in hydrophilic part can theoretically stick out of the liposome surface, making it a perfect substrate for Glut1 overexpressed on tumor cells [32,33]. Consequently, Rg3 can act as a liposomal membrane stabilizer, an adjuvant agent and an active tumor targeting ligand without additional chemical modifications.…”